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1

Properties of duplex stainless steels made by powder metallurgy  

Microsoft Academic Search

Purpose: of this paper was to examine the mechanical properties of duplex stainless steels. Design\\/methodology\\/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, martensitic base powders by controlled addition of alloying elements, such as Cr, Ni, Mo and Cu. In the studies behind the preparation of mixes, Schaeffler's diagram was taken into consideration. Prepared

L. A. Dobrzaski; Z. Brytan; M. Actis Grande; M. Rosso

2

Enhance hydration properties of steel slag using grinding aids by mechanochemical effect  

Microsoft Academic Search

Basic oxygen furnace steel slag is a kind of cementitious material with low activity and hard for grinding. The objective of this work was to validate specious grinding aids F1 made in lab which was effective for the grinding of steel slag, thus enhancing the hydration properties. By using 0.05% F1, the Blaine value of steel slag was added up

Xi Zhu; Haobo Hou; Xuquan Huang; Min Zhou; Weixin Wang

3

Pressure vessel steel embrittlement monitoring by magnetic properties measurements  

Microsoft Academic Search

The magnetic properties of specimens of one heat of A533B nuclear pressure vessel grade steel have been examined in the as-received condition and after neutron irradiation to various fluence levels up to 4 [times] 10[sup 18] cm[sup [minus]2] (E > 0.1 MeV) in the University of Illinois Advanced TRIGA reactor core at two temperatures, approximately 120 and 260[degrees]C. The effect

J. F. Stubbins; W. J. Shong; M. Giacobbe; A. M. Ougouag; J. G. Williams

1992-01-01

4

Pressure vessel steel embrittlement monitoring by magnetic properties measurements  

Microsoft Academic Search

The magnetic properties of specimens of one heat of A533B nuclear pressure vessel grade steel have been examined in the as-received condition and after neutron irradiation to various fluence levels up to 4 10¹⁸ cm⁻² (E > 0.1 MeV) in the University of Illinois Advanced TRIGA reactor core at two temperatures, approximately 120 and 260°C. The effect of some

J. F. Stubbins; W. J. Shong; M. Giacobbe; A. M. Ougouag; J. G. Williams

1992-01-01

5

Local magnetic properties in grain-oriented electrical steel measured by the modified needle probe method  

NASA Astrophysics Data System (ADS)

Distribution of local magnetic properties in grain-oriented electrical steel was investigated using the needle probe method. The spatial nonuniformity of flux density was found to be affected by magentic poles on grain boundaries which mainly depend on the ? angles between neighbouring grains and on the direction of grain boundaries.

Senda, K.; Kurosawa, M.; Ishida, M.; Komatsubara, M.; Yamaguchi, T.

2000-06-01

6

Ultrafine Grained Steels Fabricated by Novel Processes Microstructure Evolution & Mechanical Properties  

Microsoft Academic Search

Ultrafine grained (UFG) steels whose mean grain sizes are smaller than 1 ?m have been energetically studied in this 5 years. It is expected that ultra-grain refinement would enable us to have the advanced steels with superior properties in simple chemical compositions. Severe plastic deformation (SPD) and ultimate thermomechanical processing have realized the UFG steels at least in laboratory levels.

Nobuhiro Tsuji

2002-01-01

7

Effect of charging energy on droplet diameters and properties of high-carbon steel coatings sprayed by wire explosion spraying  

Microsoft Academic Search

The purpose of this study is to investigate the effect of charging energy on droplet diameters and the properties of high-carbon steel coatings sprayed by wire explosion spraying. With different charging energies, droplets were collected when high-carbon steel wire explosion occurred, and the coatings were sprayed on aluminum alloy substrates. Droplet diameter distributions were obtained by using a Laser Particle

Qing Li; Qiu-zhi Song; Jian-zhong Wang; Ying-xian Duo

2011-01-01

8

Surface properties of low alloy steel treated by plasma nitrocarburizing prior to laser quenching process  

NASA Astrophysics Data System (ADS)

Laser quenching (LQ) technique is used as a part of duplex treatments to improve the thickness and hardness of the surface layers of steels. The present study is to investigate the surface properties of low alloy steel treated by plasma nitrocarburizing (PNC) prior to a laser quenching process (PNC+LQ). The microstructure and properties of PNC+LQ layer determined are compared with those obtained by PNC and LQ processes. OM, XRD, SEM and EDS analyses are utilized for microstructure observation, phases identification, morphology observation and chemical composition detection, respectively. Microhardness tester and pin-on-disc tribometer are used to investigate the mechanical properties of the modified layers. Laser quenching of plasma nitrocarburized (PNC+LQ) steel results in much improved thickness and hardness of the modified layer in comparison with the PNC or LQ treated specimens. The mechanism is that the introduction of trace of nitrogen decreases the eutectoid point, that is, the transformation hardened region is enlarged under the same temperature distribution. Moreover, the layer treated by PNC+LQ process exhibits enhanced wear resistance, due to the lubrication effect and optimized impact toughness, which is contributed to the formation of oxide film consisting of low nitrogen compound (FeN0.076) and iron oxidation (mainly of Fe3O4).

Wang, Y. X.; Yan, M. F.; Li, B.; Guo, L. X.; Zhang, C. S.; Zhang, Y. X.; Bai, B.; Chen, L.; Long, Z.; Li, R. W.

2015-04-01

9

Antibacterial properties and corrosion resistance of AISI 420 stainless steels implanted by silver and copper ions  

NASA Astrophysics Data System (ADS)

Silver or copper ions are often chosen as antibacterial agents. But a few reports are concerned with these two antibacterial agents for preparation of antibacterial stainless steel (SS). The antibacterial properties and corrosion resistance of AISI 420 stainless steel implanted by silver and copper ions were investigated. Due to the cooperative antibacterial effect of silver and copper ions, the Ag/Cu implanted SS showed excellent antibacterial activities against both Gram-negative Escherichia coli ( E. coli) and Gram-positive Staphylococcus aureus ( S. aureus) at a total implantation dose of 21017 ions/cm2. Electrochemical polarization curves revealed that the corrosion resistance of Ag/Cu implanted SS was slightly enhanced as compared with that of un-implanted SS. The implanted layer was characterized by X-ray photoelectron spectroscopy (XPS). Core level XPS spectra indicate that the implanted silver and copper ions exist in metallic state in the implanted layer.

Ni, Hong-wei; Zhang, Han-shuang; Chen, Rong-sheng; Zhan, Wei-ting; Huo, Kai-fu; Zuo, Zhen-yu

2012-04-01

10

Effect of Posttreatment on Microstructure and Magnetic Properties of Si Steel Strips Prepared by Twin-Roll Continuous Casting Process  

NASA Astrophysics Data System (ADS)

On the basis of early works, Si-steel strips with 3.0 wt pct Si content were prepared by twin-roll continuous casting (TRCC); posttreatment of double cold-rolling with different annealing temperature was completed, and accordingly, optimum parameters were ascertained. The microstructure and magnetic properties of the strips before and after posttreatment were investigated. The results indicated that Si steel strips could be successfully prepared by TRCC, and the best annealing conditions for posttreatment were 1223 K (950 C) 3 minutes in the Ar. Si steel strips exhibited the best magnetic properties after optimum posttreatment: core loss of 4.31 W/Kg and magnetic induction intensity of 1.69T. Moreover, proper posttreatment resulted in ordering of Fe3Si of the Si steel strips, and this ordering was a key factor on improvement of magnetic properties.

Yi, Yu; Zhou, Zehua; Wang, Zehua; Jiang, Shaoqun; Huang, Weidong

2012-10-01

11

Impact Tensile Properties of YAG Laser Welded Butt Joints Made by Different Steel Sheets for Vehicles  

NASA Astrophysics Data System (ADS)

The tensile properties of YAG laser welded butt joints using different high strength steel sheets with a tensile strength of 270 MPa, 590 MPa and 980 MPa (denoted HR270, HR590 and HR980, respectively) were investigated at static and dynamic rates, together with the three kinds of laser welded joints made by the same steel sheets. The impact tensile tests were performed by using the vertical type of split Hopkinson tension bar apparatus, while the static tensile tests were carried out using a universal testing machine INSTRON5586. The impact tensile strengths were significantly increased in comparison with the static ones due to the effect of strain rate, which might be the contribution of the part of HR270 base metal. And in both of static and impact tests, the fracture strains of HR270-HR590 joint, HR270-HR980 joint and HR590-HR980 joint were about one half of the fracture strains observed in the same steel welded joints of HR270-HR270, HR270-HR270 and HR590-HR590, respectively.

Takahashi, Y.; Daimaruya, M.; Kobayashi, H.; Tsuda, H.; Fujiki, H.

12

Improvement of mechanical properties on metastable stainless steels by reversion heat treatments  

NASA Astrophysics Data System (ADS)

AISI 301LN is a metastable austenitic stainless steel that offers an excellent combination of high strength and ductility. This stainless grade is currently used in applications where severe forming operations are required, such as automotive bodies. When these metastable steels are plastically deformed at room temperature, for example by cold rolling, austenite transforms to martensite and, as a result, yield strength increases but ductility is reduced. Grain refinement is the only method that allows improving strength and ductility simultaneously. Several researchers have demonstrated that fine grain AISI 301LN can be obtained by heat treatment after cold rolling. This heat treatment is called reversion because it provokes the reversion of strain induced martensite to austenite. In the present work, sheets of AISI 301LN previously subjected to 20% of cold rolling reduction were treated and a refined grain austenitic microstructure was obtained. Mechanical properties, including fatigue limit, were determined and compared with those corresponding to the steel both before and after the cold rolling.

Mateo, A.; Zapata, A.; Fargas, G.

2013-12-01

13

Optimizing the mechanical properties of M50NiL steel by plasma nitrocarburizing  

NASA Astrophysics Data System (ADS)

In this study, plasma nitrocarburizing at various temperatures in the range of 460-540 C were carried out on M50NiL steel in order to improve wear properties. The nitrocarburizing temperature was optimized to obtain the best wear properties. The phase composition, microstucture and microhardness profiles of nitrocarburized layers of M50NiL steel were characterized by XRD, optical microscope and Vickers microhardness measurements, respectively. Pin-on-disc tribometer and SEM equipped with EDS were applied to measure friction and wear properties and analyze wear mechanisms involved. XRD results show that the amount of ?-Fe2-3(N,C) phase increased as the nitrocarburizing temperature rose form 460 C to 500 C and then decreased at 540 C, while the amount of ??-Fe4(N,C) phase increased as the treatment temperature rose. The hardness of the nitrocarburized layers showed an obvious improvement accompanied with the increasing nitrocarburizing temperature, and obtained the maximum surface hardness of 1287 HV at 540 C. The results of wear tests carried out at various sliding speeds indicated that the wear mechanism depends on sliding speed rather than the nitrocarburizing temperature. With the increase of the sliding speed, the wear mechanism transfers from oxidation mode to abrasive mode. The gradually deceased wear rate of the specimen nitrocarburized at 500 C with the increase of the sliding speed indicated the excellent wear resistance under high sliding speed condition. Therefore, 500 C can be selected as an optimized nitrocarburizing temperature for M50NiL steel.

Zhang, C. S.; Yan, M. F.; Sun, Z.; Wang, Y. X.; You, Y.; Bai, B.; Chen, L.; Long, Z.; Li, R. W.

2014-10-01

14

Fatigue properties of a biomedical 316L steel processed by surface mechanical attrition  

NASA Astrophysics Data System (ADS)

This work deals with the influence of surface mechanical attrition treatment (SMAT) on fatigue properties of a medical grade 316L stainless steel. Metallurgical parameters governed by SMAT such as micro-hardness and nanocrystalline layer are characterized using different techniques. Low cycle fatigue tests are performed to investigate the fatigue properties of untreated and SMAT-processed samples. The results show that the stress amplitude of SMAT- processed samples with two different treatment intensities is significantly enhanced compared to untreated samples, while the fatigue strength represented by the number of cycles to failure is not improved in the investigated strain range. The enhancement in the stress amplitude of treated samples can be attributed to the influence of the SMAT affected layer.

Sun, Z.; Chemkhi, M.; Kanoute, P.; Retraint, D.

2014-08-01

15

The effect of ultrasonics on the strength properties of carbon steel processed by cold plastic deformation  

NASA Technical Reports Server (NTRS)

A study was made of the influence of ultrasounds on the mechanical properties of OLT 35 carbon steel tubes cold-drawn on a plug ultrasonically activated by longitudinal waves. Experimental results indicate that: 1. The reduction in the values of the flow limit and tensile strength is proportional to the increase in acoustic energy introduced into the material subjected to deformation. 2. The diminution in influence of ultrasounds on tensile strength and flow rate that is due to an increased degree of deformation is explained by a reduction in specific density of the acoustic energy at the focus of deformation. 3. The relations calculated on the basis of the variation in the flow limit and tensile strength as a function of acoustic energy intensity was verified experimentally.

Atanasiu, N.; Dragan, O.; Atanasiu, Z.

1974-01-01

16

Detection of the weak magnetic properties change of stainless-steel welding parts by low frequency magnetic imaging  

NASA Astrophysics Data System (ADS)

Differences in weld quality resulting from variations in welding conditions were detected via low frequency magnetic imaging. This magnetic imaging was obtained using a recently developed measurement system, consisting of an exposure coil, a magnetoresistive (MR) sensor, and a lock-in amplifier. A wide area of stainless-steel sample was exposed to the magnetic field via an induction coil, and the MR sensor measured the generated magnetic field from the sample. The frequency of the magnetic field ranged from 20Hzto1kHz. A cylindrical stainless-steel sample was fabricated by rolling a stainless-steel sheet and welding each edge by an arc welder with argon gas, while the welding condition was changed by controlling the argon gas flow. The magnitude and phase shift of the generated magnetic field from the sample was measured by scanning the MR sensor on the sample surface. The change in magnetic properties caused by the welding condition change was successfully imaged.

Hayashi, Takayuki; Yamada, Hironobu; Kiwa, Toshihiko; Tsukada, Keiji; Tamazumi, Masaji

2008-04-01

17

Relationship between binder contents and mechanical properties of 17-4 ph stainless steel fabricated by PIM process and sintering  

Microsoft Academic Search

Mechanical properties and microstructures of 17-4 ph stainless steel parts produced using different binder contents (powder\\u000a loading) of powder injection molding (PIM) feedstock have been studied. The tensile and wear properties have been evaluated.\\u000a Wear tests were conducted by a pin-on-disk tribometer, without lubricant, at different loads and sliding distance. SEM examination\\u000a of the fracture sufaces revealed good particle bonding

K. A. Khalil; Sug Won Kim

2006-01-01

18

Mechanical Properties of Bulk Nanocrystalline Austenitic Stainless Steels Produced by Equal Channel Angular Pressing  

E-print Network

Bulk nanocrystalline 304L and 316 L austenitic stainless steels (SS) were produced by equal channel angular pressing(ECAP) at elevated temperature. The average grain size achieved in 316 L and 304 L SS is ~ 100 nm, and grain refinement occurs more...

Gonzalez, Jeremy

2012-10-19

19

Stainless Steel Microstructure and Mechanical Properties Evaluation  

SciTech Connect

A nitrogen strengthened 21-6-9 stainless steel plate was spinformed into hemispherical test shapes. A battery of laboratory tests was used to characterize the hemispheres. The laboratory tests show that near the pole (axis) of a spinformed hemisphere the yield strength is the lowest because this area endures the least cold-work strengthening, i.e., the least deformation. The characterization indicated that stress-relief annealing spinformed stainless steel hemispheres does not degrade mechanical properties. Stress-relief annealing reduces residual stresses while maintaining relatively high mechanical properties. Full annealing completely eliminates residual stresses, but reduces yield strength by about 30%.

Switzner, Nathan T

2010-06-01

20

Tensile properties of modified 9Cr1Mo steel by shear punch testing and correlation with microstructures  

Microsoft Academic Search

Modified 9Cr-1Mo ferritic steel (P91) is subjected to a series of heat treatments consisting of soaking for 5min at the selected temperatures in the range 973K1623K (below Ac1 to above Ac4) followed by oil quenching and tempering at 1033K for 1h to obtain different microstructural conditions. The tensile properties of the different microstructural conditions are evaluated from small volumes of

V. Karthik; K. Laha; P. Parameswaran; K. S. Chandravathi; K. V. Kasiviswanathan; T. Jayakumar; Baldev Raj

2011-01-01

21

Properties of a new family of stainless steels without nickel  

Microsoft Academic Search

Many applications in which stainless steels are employed call for good corrosion resistance and, at the same time, for good\\u000a weldability. The new family of stainless steels which we propose to describe is related by its structure to the steels of\\u000a the ferritic group and by its properties,i.e., the ductility of its welds and its corrosion resistance, to the steels

J. Lefevre; R. Tricot; A. Gueussier; R. Castro

1974-01-01

22

The mechanical properties of H13 die steel repaired by a biomimetic laser technique  

NASA Astrophysics Data System (ADS)

The H13 steel specimens with cracks were repaired by pulsed laser welding with filler wire and the laser parameters were analyzed to obtain the weld without defects. Strengthening units with different spacing were fabricated to improve the tensile strength and thermal fatigue resistance of the weld by laser technique on the surfaces of specimens, that is, PS-1, PS-2 and PS-3 for tensile specimens and PS for thermal fatigue specimen. The results indicated that the units have a beneficial effect on improving the tensile strength and thermal fatigue resistance of welded components of H13 steel. The improvement can be attributed to the microstructure characteristics within the units and the spacing of adjacent units is a key factor which affects the strength of weld by biomimetic treatment.

Cong, Dalong; Zhou, Hong; Yang, Miaoqiang; Zhang, Zhihui; Zhang, Peng; Meng, Chao; Wang, Chuanwei

2013-12-01

23

Characterization of a boron alloyed 9Cr3W3CoVNbBN steel and further improvement of its high-temperature mechanical properties by thermomechanical treatments  

NASA Astrophysics Data System (ADS)

In the framework of the development of Generation IV nuclear reactors and fusion nuclear reactors, materials with an improved high temperature (?650 C) mechanical strength are required for specific components. The 9-12% Cr martensitic steels are candidate for these applications. Previous works showed that the application of a thermomechanical treatment, including warm-rolling in metastable austenitic phase, to the commercial Grade 91 martensitic steel, allowed refining its microstructure, improving its precipitation state and its mechanical properties (hardness, tensile and creep properties). In the present paper, experimental steel called NPM, designed for good high-temperature creep resistance, is evaluated in terms of microstructure and mechanical properties, and compared to the G91 steel. Then the developed thermomechanical treatment is applied to this steel. Its microstructure is refined and its hardness and tensile properties are much better than the as-received NPM and therefore than the G91 steel. The cyclic softening effect still occurs for the optimized NPM, but this material once softened by cyclic loadings, still presents better creep properties than the as-received NPM steel, and even more than the commercial G91 steel.

Hollner, S.; Piozin, E.; Mayr, P.; Cas, C.; Tourni, I.; Pineau, A.; Fournier, B.

2013-10-01

24

Effect of Mo substitution by W on impact property of heat affected zone in duplex stainless steels  

Microsoft Academic Search

The duplex stainless steels are characterized by two phase structures composed of a mixture of austenite and ferrite phases. They offer high toughness, good weldability, satisfactory corrosion protection, excellent stress corrosion cracking resistance and high strength. Because of these characteristics, these steels have been widely used in various applications such as oil, gas, and chemical industries. Duplex stainless steels generally

Mann Joo Huh; Sang Beom Kim; Kyung Wook Paik; Young Gil Kim

1997-01-01

25

Magnetic properties of stainless steels at room and cryogenic temperatures  

NASA Astrophysics Data System (ADS)

The magnetic properties of ten types of ferritic and martensitic stainless steels have been measured at room temperature and at 77 K. The steel samples studied were in the annealed state as received from the manufacturer. Our room temperature measurements indicate significantly harder magnetic properties than those quoted in the ASM International Handbook, which studied fully annealed stainless steel samples. Despite having harder magnetic properties than fully annealed steels some of the as-received steels still display soft magnetic properties adequate for magnetic applications. The carbon content of the steels was found to affect the permeability and coercive force, with lower-carbon steels displaying significantly higher permeability and lower coercive force. The decrease in coercive force with reduced carbon content is attributed to fewer carbide inclusions which inhibit domain wall motion. Cooling to 77 K resulted in harder magnetic properties. Averaged over the ten steels tested the maximum permeability decreased by 8%, the coercive force increased by 14%, and the residual and saturation flux densities increased by 4% and 3%, respectively. The change in coercive force when cooled is comparable to the theoretical prediction for iron, based on a model of domain wall motion inhibited by inclusions. The modest changes of the magnetic properties indicate that the stainless steels can still be used in magnetic applications at very low temperatures.

Oxley, Paul; Goodell, Jennifer; Molt, Robert

2009-07-01

26

Effect of hardening by grinding on the structure and properties of steel 45  

Microsoft Academic Search

al specimens 60 mm in diameter made of steel 45 normalized from 850C with an initial ferritepearlite structure were used. A grinding wheel 25A40S26K5 was used. Grinding speed was 35 m\\/sec, cutting depth was 0.25-1.5 mm, and the part rotation rate (circular feed) was 3-9 mm\\/sec. Temperature was determined by a Chromel--Alumel thermocouple KhA02 with 0.2-mm electrode diameter. Metallographic studies

I. S. Kozlovskii; Ya. M. Naerman

1982-01-01

27

Surface property enhancement by RE-borosulphurizing on high-carbon steel  

NASA Astrophysics Data System (ADS)

Pack boronizing and rare-earth (RE)-borosulphurizing of high-carbon steel (T8) were conducted at 950 ?C for 6 h. Characterizations of the layers formed on the surface of the high carbon steel were carried out by metallographic techniques, scanning electron microscopy, Auger electron spectroscopy and wear and corrosion resistance tests. It has been revealed that the diffusion front of the boride layer (BL) has a sawtooth shape, while that of the RE-borosulfide layer (RBSL) is flat. Different from the BL layer, the RBSL layer is compact, continuous and flat. The formation of FeS, Fe2B and FeB phases on the substrates was confirmed by Auger electron spectroscopy analysis. The wear resistance test indicated that within a certain range, the abrasion resistance of the RBSL layer is better than that of the BL layer, especially under high-load conditions. The corrosion resistance test using the weight loss method has shown that the corrosion resistance of the RBSL layer is better but decreases faster with time extension than that of the BL layer.

Wang, Dong; Zhang, Xiu-li; Zhao, Han-yu; Li, Yun-dong

2013-10-01

28

Properties of bacterial corrosion of stainless steel and its inhibition by protamine coating.  

PubMed

We investigated characteristics of the corrosion of stainless steel specimens by bacteria and the effects of using antimicrobial coating on the surface for inhibiting corrosion. Bacillus sp. 2-A and Staphylococcus sp. 2-1 cells adhered tightly to a stainless steel SUS304 specimen, formed a microcolony or biofilm, and had highly corrosive activities. Microbially influenced corrosion (MC) was observed under or around adhering cells. However, dead cells were markedly less active than viable cells not only in corroding the specimen but also in adhering to its surface. The culture supernatant was not able to induce the corrosion of SUS304 effectively. A protamine coating on the specimen killed bacterial cells only on its surface, interfered with cell adhesion, and inhibited MC. From these results, adhesion of viable cells to the surface of a SUS304 specimen led to the outbreak of MC. Protamine was also found to be an effective substance tested for protecting the specimen from both cell adhesion and surface MC. We suggest that a protamine coating can be applied as a convenient and inexpensive corrosion prevention method. PMID:17408005

Matsumura, Yoshinobu; Yamada, Kaoru; Takahashi, Mitsuo; Kikuchi, Yasushi; Tsuchido, Tetsuaki

2007-03-01

29

A comparative study of the mechanical properties and the behavior of carbon and boron in stainless steel cladding tubes fabricated by PM HIP and traditional technologies  

NASA Astrophysics Data System (ADS)

The ring tensile test method was optimized and successfully used to obtain precise data for specimens of the cladding tubes of AISI type 316 austenitic stainless steels and ferritic-martensitic stainless steel. The positive modifications in the tensile properties of the stainless steel cladding tubes fabricated by powder metallurgy and hot isostatic pressing of melt atomized powders (PM HIP) when compared with the cladding tubes produced by traditional technology were found. Presently, PM HIP is also used in the fabrication of oxide dispersion strengthened (ODS) ferritic-martensitic steels. The high degree of homogeneity of the distribution of carbon and boron as well the high dispersivity of the phase-structure elements in the specimens manufactured via PM HIP were determined by direct autoradiography methods. These results correlate well with the increase of the tensile properties of the specimens produced by PM HIP technology.

Shulga, A. V.

2013-03-01

30

Advances in chemical and physical properties of electric arc furnace carbon steel slag by hot stage processing and mineral mixing.  

PubMed

Slags are recognised as a highly efficient, cost effective tool in the metal processing industry, by minimising heat losses, reducing metal oxidation through contact with air, removing metal impurities and protecting refractories and graphite electrodes. When compared to natural aggregates for use in the construction industry, slags have higher specific weight that acts as an economic deterrent. A method of altering the specific weight of EAFC slag by hot stage processing and mineral mixing, during steel production is presented in this article. The method has minimal interference with the production process of steel, even by limited additions of appropriate minerals at high temperatures. Five minerals are examined, namely perlite, ladle furnace slag, bauxite, diatomite and olivine. Measurements of specific weight are accompanied by X-ray diffraction (XRD) and fluorescence (XRF) analysis and scanning electron microscopy spectral images. It is also shown how altering the chemical composition is expected to affect the furnace refractory lining. Additionally, the process has been repeated for the most suitable mix in gas furnace and physical properties (FI, SI, LA, PSV, AAV, volume stability) examined. Alteration of the specific weight can result in tailoring slag properties for specific applications in the construction sector. PMID:25261762

Liapis, Ioannis; Papayianni, Ioanna

2015-02-11

31

Estimation of mechanical properties of irradiated nuclear pressure vessel steel by use of subsized CT specimen and small punch specimen  

Microsoft Academic Search

This paper reports on the 2-1\\/4 Cr-1M steel that has been selected as the material for the reactor pressure vessel (RPV) of a multipurpose experimental high temperature gas cooled reactor designed by JAERI. The 2-1\\/4 Cr-1M steel has successful records for high temperature pressure vessels in the petrochemical industries and the ASME Code Case authorizes the use of the steel

X. Mao; H. Takahashi; T. Kodaira

1991-01-01

32

Interfacial mechanical properties of TiN coating on steels by indentation  

Microsoft Academic Search

The elastic theory of indentation on nitride films\\/steel systems showed distribution of stresses (shear stress, radial stress\\u000a and circumferential stress) near the interface and in the film. The difference in values for each stress along the distance\\u000a to the load center increased with increasing Poissons ratios of steels. The shear stresses (?rz) had the maximum value at a distance to

Shi-Yung Chiou; Dershin Gan

2007-01-01

33

Iron and Steel- Properties and Applications  

NSDL National Science Digital Library

This document provides a learning module on iron and steel for use in materials education. The lesson examines the basic properties of iron and steel and includes discussions, demonstrations and suggested optional classroom activities. The materials can be covered in one to two class periods.

Stoebe, Thomas G.

34

The mechansims by which solute nitrogen affects phase transformations and mechanical properties of automotive dual-phase sheet steel  

NASA Astrophysics Data System (ADS)

Dual-phase steels have seen increased use in automotive applications in recent years, in order to meet the goals of weight reduction and occupant safety. Variations in nitrogen content that may be encountered in steel sourced from a basic oxygen furnace process compared to an electric arc furnace process require that dual-phase steel producers understand the ways that nitrogen affects processing and properties. In the current work, the distribution of nitrogen was investigated in a dual-phase steel with a base chemistry of 0.1 C, 2.0 Mn, 0.2 Cr, 0.2 Mo (wt pct) across a range of nitrogen contents (30-159 ppm) with Al (0.2 and 0.08 wt pct), and Ti (0.02 wt pct) additions used for precipitation control of nitrogen amounts. The distribution of nitrogen amongst trapping sites, including precipitates, grain boundaries, dislocations, and interstitial sites (away from other types of defects) was determined from a combination of electrolytic dissolution, internal friction, and three-dimensional atom probe tomography experiments. Various mechanisms by which different amounts and locations of nitrogen affect phase transformations and mechanical properties were identified from quantitative metallography, dilatometric measurement of phase transformations, tensile testing, and nanoindentation hardness testing. Results indicate nitrogen that is not precipitated with Ti or Al (free nitrogen) partitions to austenite (and thus martensite) during typical intercritical annealing treatments, and is mostly contained in Cottrell atmospheres in martensite. Due to the austenite stabilizing effect of nitrogen, the presence of free nitrogen during intercritical annealing leads to a higher austenite fraction in certain conditions. Thus, the presence of free nitrogen in a dual-phase microstructure will lead to an increase in tensile and yield strengths from both an increase in martensite fraction, and an increase in martensite hardness due to solid solution strengthening. Despite the presence of free nitrogen, no yield point elongation was detected in tensile stress-strain results, including after 80 C aging treatments. This was likely due to the partitioning of nitrogen, such that the ferritic regions of the microstructure contained less nitrogen than is required to saturate the high dislocation density in ferrite. Measured tensile and yield strength sensitivities to free nitrogen content range between 7 and 13 GPa/wt pct N.

Brown, Tyson W.

35

Effect of heat treatments on tensile properties of F82H steel irradiated by neutrons  

NASA Astrophysics Data System (ADS)

The dependence of irradiation hardening of F82H steel on tempering conditions was examined by JMTR and HFIR irradiation experiments. The JMTR and HFIR irradiations were performed to 2 dpa at 250 C and 5 dpa at 300 C, respectively. Irradiation hardening measured at 25-400 C depended strongly on tempering conditions, and it basically increased with temperature and time of tempering. The increment of yield stress due to irradiation was negligible at 500 C in the specimens tempered at 750 C for 0.5-10 h, but was measured to be 130-200 MPa in the specimens tempered at 780 and 800 C for 0.5 h. Irradiation hardening of F82H that was heat treated to produce a weld-like material was also examine. The weld-like material was annealed at 800, 860 and 920 C for 0.5 h, and then continuously annealed at 700 C. The level of irradiation hardening depended on the heat treatment conditions. From these results, it is suggested that the control of heat treatments such as tempering is useful to resist irradiation hardening and embrittlement.

Wakai, E.; Ando, M.; Sawai, T.; Tanigawa, H.; Taguchi, T.; Stoller, R. E.; Yamamoto, T.; Kato, Y.; Takada, F.

2007-08-01

36

Determining the shear fracture properties of HIP joints of reduced-activation ferritic/martensitic steel by a torsion test  

NASA Astrophysics Data System (ADS)

Hot isostatic pressing (HIP) is a key technology used to fabricate a first wall with cooling channels for the fusion blanket system utilizing a reduced-activation ferritic/martensitic steel. To qualify the HIPped components, small specimen test techniques are beneficial not only to evaluate the thin-wall cooling channels containing the HIP joint but also to use in neutron irradiation studies. This study aims to develop the torsion test method with special emphasis on providing a reasonable and comprehensive method to determine interfacial shear properties of HIP joints during the torsional fracture process. Torsion test results identified that the torsion process shows yield of the base metal followed by non-elastic deformation due to work hardening of the base metal. By considering this work hardening issue, we propose a reasonable and realistic solution to determine the torsional yield shear stress and the ultimate torsional shear strength of the HIPped interface. Finally, a representative torsion fracture process was identified.

Nozawa, Takashi; Noh, Sanghoon; Tanigawa, Hiroyasu

2012-08-01

37

Wear and corrosion properties of a low carbon steel processed by means of SMAT followed by lower temperature chromizing treatment  

Microsoft Academic Search

A duplex lower temperature chromizing treatment at 600C for 120min followed by 860C for 90min was performed on a low carbon steel plate with a nanostructured surface layer, induced by surface mechanical attrition treatment (SMAT) [Z.B. Wang, J. Lu, K. Lu, Acta Mater. 53 (2005) 2081]. Microhardness, wear and corrosion resistances of the chromized SMAT sample were measured, in comparison

Z. B. Wang; J. Lu; K. Lu

2006-01-01

38

Material property evaluations of bimetallic welds, stainless steel saw fusion lines, and materials affected by dynamic strain aging  

SciTech Connect

Pipe fracture analyses can often reasonably predict the behavior of flawed piping. However, there are material applications with uncertainties in fracture behavior. This paper summarizes work on three such cases. First, the fracture behavior of bimetallic welds are discussed. The purpose of the study was to determine if current fracture analyses can predict the response of pipe with flaws in bimetallic welds. The weld joined sections of A516 Grade 70 carbon steel to F316 stainless steel. The crack was along the carbon steel base metal to Inconel 182 weld metal fusion line. Material properties from tensile and C(T) specimens were used to predict large pipe response. The major conclusion from the work is that fracture behavior of the weld could be evaluated with reasonable accuracy using properties of the carbon steel pipe and conventional J-estimation analyses. However, results may not be generally true for all bimetallic welds. Second, the toughness of austenitic steel submerged-arc weld (SAW) fusion lines is discussed. During large-scale pipe tests with flaws in the center of the SAW, the crack tended to grow into the fusion line. The fracture toughness of the base metal, the SAW, and the fusion line were determined and compared. The major conclusion reached is that although the fusion line had a higher initiation toughness than the weld metal, the fusion-line J-R curve reached a steady-state value while the SAW J-R curve increased. Last, carbon steel fracture experiments containing circumferential flaws with periods of unstable crack jumps during steady ductile tearing are discussed. These instabilities are believed to be due to dynamic strain aging (DSA). The paper discusses DSA, a screening criteria developed to predict DSA, and the ability of the current J-based methodologies to assess the effect of these crack instabilities. The effect of loading rate on the strength and toughness of several different carbon steel pipes at LWR temperatures is also discussed.

Rudland, D.; Scott, P.; Marschall, C.; Wilkowski, G. [Battelle Memorial Institute, Columbus, OH (United States)

1997-04-01

39

Complex Mechanical Properties of Steel  

E-print Network

Whereas considerable progress has been reported on the quantitative estimation of the microstructure of steels as a function of most of the important determining variables, it remains the case that it is impossible to calculate all but the simplest...

Dimitriu, Radu

40

Domains of Steels with Identical Properties  

Microsoft Academic Search

There have been many attempts in the past to reduce the variety of steels produced without compromising the range of properties available. The objective in doing so is to reduce costs. These attempts have largely focused on experiments in which thermomechanical processing parameters are varied in order to obtain a range of properties without changing the chemical composition.We have approached

Minsung Joo; Joohyun Ryu; H. K. D. H. Bhadeshia

2008-01-01

41

Thermophysical property sensitivity effects in steel solidification  

NASA Technical Reports Server (NTRS)

The simulation of advanced solidification processes via digital computer techniques has gained widespread acceptance during the last decade or so. Models today can predict transient temperature fields, fluid flow fields, important microstructural parameters, and potential defects in castings. However, the lack of accurate thermophysical property data on important industrial alloys threatens to limit the ability of manufacturers to fully capitalize on the technology's benefits. A study of the sensitivity of one such numerical model of a steel plate casting to imposed variations in the data utilized for the thermal conductivity, specific heat, density, and heat of fusion is described. The sensitivity of the data's variability is characterized by its effects on the net solidification time of various points along the centerline of the plate casting. Recommendations for property measurements are given and the implications of data uncertainty for modelers are discussed.

Overfelt, Tony

1993-01-01

42

Improvement of mechanical and tribological properties in steel surfaces by using titanium-aluminum/titanium-aluminum nitride multilayered system  

NASA Astrophysics Data System (ADS)

Improvement of mechanical and tribological properties on AISI D3 steel surfaces coated with [Ti-Al/Ti-Al-N]n multilayer systems deposited in various bilayer periods (?) via magnetron co-sputtering pulsed d.c. method, from a metallic binary target; has been studied in this work exhaustively. The multilayer coatings were characterized in terms of structural, chemical, morphological, mechanical and tribological properties by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy, nanoindentation, pin-on-disc and scratch tests, respectively. The failure mode mechanisms were studied by optical microscopy. Results from X-ray diffraction analysis revealed that the crystal structure of TiAl/TiAlN multilayer coatings has a tetragonal and FCC NaCl-type lattice structures for Ti-Al and Ti-Al-N, respectively, i.e., it was found to be non-isostructural multilayers. An enhancement of both hardness and elastic modulus up to 29 GPa and 260 GPa, respectively, was observed as the bilayer periods (?) in the coatings were decreased. The sample with a bilayer period (?) of 25 nm and bilayer number n = 100 showed the lowest friction coefficient (?0.28) and the highest critical load (45 N), corresponding to 2.7 and 1.5 times better than those values for the coating deposited with n = 1, respectively. These results indicate an enhancement of mechanical, tribological and adhesion properties, comparing to the [Ti-Al/Ti-Al-N]n multilayer systems with 1 bilayer at 26%, 63% and 33%, respectively. This enhancement in hardness and toughness for multilayer coatings could be attributed to the different mechanisms for layer formation with nanometric thickness such as the novel Ti-Al/Ti-Al-N effect and the number of interfaces that act as obstacles for the crack deflection and dissipation of crack energy.

Ipaz, L.; Caicedo, J. C.; Esteve, J.; Espinoza-Beltran, F. J.; Zambrano, G.

2012-02-01

43

Properties of cryogenically worked metals. [stainless steels  

NASA Technical Reports Server (NTRS)

A program was conducted to determine whether the mechanical properties of cryogenically worked 17-7PH stainless steel are suitable for service from ambient to cryogenic temperatures. It was determined that the stress corrosion resistance of the cryo-worked material is quite adequate for structural service. The tensile properties and fracture toughness at room temperature were comparable to titanium alloy 6Al-4V. However, at cryogenic temperatures, the properties were not sufficient to recommend consideration for structural service.

Schwartzberg, F. R.; Kiefer, T. F.

1975-01-01

44

Experimental study on mechanical properties of three steels  

NASA Astrophysics Data System (ADS)

Tensile properties of three steels named A, B, and C were investigated. The quasi-static experiments were carried out by using WDW-100D computer control testing machine while the high strain-rate experiments were testing by using the Split Hopkinson Tensile Bars (SHTB). The stress-strain curves of the materials were obtained, tensile strength, elongation, and energy dissipated were acquired. From the experimental results, the Jonson-Cook constitutive model was use to describe the behaviours of materials. The results showed that steel B had highest tensile strength and lowest elongation than steel A and B. The Jonson-Cook constitutive model fit followed the experimental data very well.

Qin, J. G.; Lin, Y. L.; Lu, F. Y.; Wen, X. J.

2012-08-01

45

Evaluation of the Joint-Interface Properties of SCM440-S45C Steels Joined by Friction Welding  

NASA Astrophysics Data System (ADS)

The purpose of this study is to investigate experimentally the hardness distributions and micro-structural properties of the dissimilar joints using chrome molybdenum steel (SCM440) to carbon steel (S45C) parts. The experiments were carried out using a beforehand designed and constructed experimental friction welding set-up, constructed as a continuous-drive brake type. The pilot dissimilar welding experiments under different friction pressure and friction time were carried out to obtain optimum welding parameters using visual examination and tensile tests. Vicker's hardness distributions and microstructures in the interfaces of the dissimilar joints for PWHT were also obtained and examined. The obtained results were compared with those of the previous study.

Kim, Seon-Jin; Kong, Yu-Sik; Yoon, Han-Ki; Jung, Won-Taek; Choi, Sung-Woong

46

Tensile Properties of Austenitic Stainless Steel  

E-print Network

the nonlinear trends of steel strength, attention was diverted to neural networks, which can allow to be in good agreement with the literature and the use of contour plots demonstrated the ability to capture nonlinear to optimise the properties. The data are generally analysed using linear regression models [1,2] to reveal

Cambridge, University of

47

Weld overlay cladding of high strength low alloy steel with austenitic stainless steel Structure and properties  

Microsoft Academic Search

The present work aims at studying structureproperty correlations in a weld overlay clad high strength low alloy steel with austenitic stainless steel of American Institute for Steel and Iron (AISI) 347 grade. Optical microscopy studies revealed that the interface between the two steels was nearly flat. The base plate had ferrite plus bainite microstructure adjacent to the interface and tempered

N. Venkateswara Rao; G. Madhusudhan Reddy; S. Nagarjuna

2011-01-01

48

X-ray attenuation properties of stainless steel (u)  

SciTech Connect

Stainless steel vessels are used to enclose solid materials for studying x-ray radiolysis that involves gas release from the materials. Commercially available stainless steel components are easily adapted to form a static or a dynamic condition to monitor the gas evolved from the solid materials during and after the x-ray irradiation. Experimental data published on the x-ray attenuation properties of stainless steel, however, are very scarce, especially over a wide range of x-ray energies. The objective of this work was to obtain experimental data that will be used to determine how a poly-energetic x-ray beam is attenuated by the stainless steel container wall. The data will also be used in conjunction with MCNP (Monte Carlos Nuclear Particle) modeling to develop an accurate method for determining energy absorbed in known solid samples contained in stainless steel vessels. In this study, experiments to measure the attenuation properties of stainless steel were performed for a range of bremsstrahlung x-ray beams with a maximum energy ranging from 150 keV to 10 MeV. Bremsstrahlung x-ray beams of these energies are commonly used in radiography of engineering and weapon components. The weapon surveillance community has a great interest in understanding how the x-rays in radiography affect short-term and long-term properties of weapon materials.

Wang, Lily L [Los Alamos National Laboratory; Berry, Phillip C [Los Alamos National Laboratory

2009-01-01

49

Tensile elastic properties of 18:8 chromium-nickel steel as affected by plastic deformation  

NASA Technical Reports Server (NTRS)

The relationship between stress and strain, and between stress and permanent set, for 18:8 alloy as affected by prior plastic deformation is discussed. Hysteresis and creep and their effects on the stress-strain and stress-set curves are also considered, as well as the influence of duration of the rest interval after cold work and the influence of plastic deformation on proof stresses, on the modulus of elasticity at zero stress, and on the curvature of the stress-strain line. A constant (c sub 1) is suggested to represent the variation of the modulus of elasticity with stress.

Mcadam, D J; Mebs, R W

1939-01-01

50

Magnetic properties of stainless steels at room and cryogenic temperatures  

Microsoft Academic Search

The magnetic properties of ten types of ferritic and martensitic stainless steels have been measured at room temperature and at 77K. The steel samples studied were in the annealed state as received from the manufacturer. Our room temperature measurements indicate significantly harder magnetic properties than those quoted in the ASM International Handbook, which studied fully annealed stainless steel samples. Despite

Paul Oxley; Jennifer Goodell; Robert Molt

2009-01-01

51

Tensile-property characterization of thermally aged cast stainless steels  

SciTech Connect

The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components.

Michaud, W.F.; Toben, P.T.; Soppet, W.K.; Chopra, O.K. [Argonne National Lab., IL (United States)

1994-02-01

52

Aging degradation of cast stainless steels: Effects on mechanical properties  

SciTech Connect

A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water operating conditions. Mechanical property data are presented from Charpy-impact, tensile, and J-R curve tests for several heats of cast stainless steel aged up to 10,000 h at 450, 400, 350, 320, and 290/sup 0/C. The results indicate that thermal aging increases the tensile strength and decreases the impact energy, J/sub IC/, and tearing modulus of the steels. Also, the ductile-to-brittle transition curve shifts to higher temperatures. The fracture toughness results are consistent with the Charpy-impact data, i.e., the relative reduction in J/sub IC/ is similar to the relative decrease in impact energy. The ferrite content and concentration of C in the steel have a strong effect on the overall process of low-temperature embrittlement. The low-carbon CF-3 steels are the most resistant and Mo-containing CF-8M steels are most susceptible to embrittlement. Weakening of the ferrite/austenite phase boundaries by carbide precipitates has a significant effect on the kinetics and extent of embrittlement of the high-carbon CF-8 and CF-8M steels, particularly after aging at temperatures greater than or equal to400/sup 0/C. The influence of N content and distribution of ferrite on loss of toughness are discussed. The data also indicate that existing correlations do not accurately represent the embrittlement behavior over the temperature range 280 to 450/sup 0/C, i.e., extrapolation of high-temperature data to reactor temperatures may not be valid for some compositions of cast stainless steel.

Chopra, O.K.; Chung, H.M.

1987-06-01

53

Effect of sintering temperature on properties of MgB 2 wire sheathed by low carbon steel tube  

NASA Astrophysics Data System (ADS)

MgB 2 wire was fabricated through the in situ powder-in-tube method in flowing argon by using low carbon steel (LCS) tube as sheath material. Effects of sintering temperature on the phase composition, microstructure features and critical current density ( Jc) are investigated by using X-ray diffractometer, scanning electron microscopy with an energy dispersive spectrometer and the standard DC four-probe technique. The result indicates that the highest Jc values have been achieved in the sample sintered at 700 C, while Jc decreases with increasing sintering temperature. It is found that microstructure features in all samples, e.g. the thickness of interface layer, the phase composition and the size of MgB 2 grain are responsible for the difference of Jc values.

Xu, H. L.; Feng, Y.; Xu, Z.; Li, C. S.; Yan, G.; Mossang, E.; Sulpice, A.

2005-03-01

54

Microstructural Characterization and Properties Evaluation of Ni-Based Hardfaced Coating on AISI 304 Stainless Steel by High Velocity Oxyfuel Coating Technique  

NASA Astrophysics Data System (ADS)

The present study concerns a detailed investigation of microstructural evolution of nickel based hardfaced coating on AISI 304 stainless steel by high velocity oxy-fuel (HVOF) deposition technique. The work has also been extended to study the effect of coating on microhardness, wear resistance and corrosion resistance of the surface. Deposition has been conducted on sand blasted AISI 304 stainless steel by HVOF spraying technique using nickel (Ni)-based alloy [Ni: 68.4 wt pct, chromium (Cr): 17 wt pct, boron (B): 3.9 wt pct, silicon (Si): 4.9 wt pct and iron (Fe): 5.8 wt pct] of particle size 45 to 60 ?m as precursor powder. Under the optimum process parameters, deposition leads to development of nano-borides (of chromium, Cr2B and nickel, Ni3B) dispersion in metastable and partly amorphous gamma nickel (?-Ni) matrix. The microhardness of the coating was significantly enhanced to 935 VHN as compared to 215 VHN of as-received substrate due to dispersion of nano-borides in grain refined and partly amorphous nickel matrix. Wear resistance property under fretting wear condition against WC indenter was improved in as-deposited layer (wear rate of 4.65 10-7 mm3/mm) as compared to as-received substrate (wear rate of 20.81 10-7 mm3/mm). The corrosion resistance property in a 3.56 wt pct NaCl solution was also improved.

Sharma, Prashant; Majumdar, Jyotsna Dutta

2013-01-01

55

Fatigue Properties of DLC-Coated Stainless Steel  

NASA Astrophysics Data System (ADS)

This study was conducted to investigate the effect of DLC (diamond-like carbon) coating on fatigue properties of austenitic stainless steel SUS304. For the DLC coating, UBMS (unbalanced magnetron sputtering) equipment was used. The generated surface layer of about 2 ?m thickness was composed of both the DLC layer possessing high hardness and a very thin intermediate layer to improve adhesion force between the DLC layer and the substrate. DLC coating, which was carried out at a relatively low temperature, had no influence on the microstructure so that the mechanical properties of the stainless steel were unchanged by the coating. The results of the plane-bending fatigue test showed that the DLC coating improved fatigue strength by 18%. From the results of detailed observation conducted on the fatigue fracture surface, it was suggested that the improvement in fatigue strength resulted from the suppression of fatigue crack initiation due to the surface layer, which had high adhesion force and strength.

Morita, Tatsuro; Tomita, Kouta; Kagaya, Chuji; Kumakiri, Tadashi; Ikenaga, Masaru

56

Magnetic properties of single crystalline expanded austenite obtained by plasma nitriding of austenitic stainless steel single crystals.  

PubMed

Ferromagnetic single crystalline [100], [110], and [111]-oriented expanded austenite is obtained by plasma nitriding of paramagnetic 316L austenitic stainless steel single crystals at either 300 or 400 C. After nitriding at 400 C, the [100] direction appears to constitute the magnetic easy axis due to the interplay between a large lattice expansion and the expected decomposition of the expanded austenite, which results in Fe- and Ni-enriched areas. However, a complex combination of uniaxial (i.e., twofold) and biaxial (i.e., fourfold) in-plane magnetic anisotropies is encountered. It is suggested that the former is related to residual stress-induced effects while the latter is associated to the in-plane projections of the cubic lattice symmetry. Increasing the processing temperature strengthens the biaxial in-plane anisotropy in detriment of the uniaxial contribution, in agreement with a more homogeneous structure of expanded austenite with lower residual stresses. In contrast to polycrystalline expanded austenite, single crystalline expanded austenite exhibits its magnetic easy axes along basic directions. PMID:24028676

Menndez, Enric; Templier, Claude; Garcia-Ramirez, Pablo; Santiso, Jos; Vantomme, Andr; Temst, Kristiaan; Nogus, Josep

2013-10-23

57

Improved life of die casting dies of H13 steel by attaining improved mechanical properties and distortion control during heat treatment. Year 1 report, October 1994--September 1995  

SciTech Connect

Optimum heat treatment of dies (quenching) is critical in ensuring satisfactory service performance: rapid cooling rates increase the thermal fatigue/heat checking resistance of the steel, although very fast cooling rates can also lead to distortion and lower fracture toughness, increasing the danger of catastrophic fracture. Goal of this project is to increase die life by using fast enough quenching rates (> 30 F/min ave cooling rate from 1750 to 550 F, 1/2 in. below working surfaces) to obtain good toughness and fatigue resistance in Premium grade H-13 steel dies. An iterative approach of computer modeling validated by experiment was taken. Cooling curves during gas quenching of H-13 blocks and die shapes were measured under 2, 5, and 7.5 bar N2 and 4 bar Ar. Resulting dimensional changes and residual stresses were determined. To facilitate the computer modeling work, a database of H-13 mechanical and physical properties was compiled. Finite element analysis of the heat treated shapes was conducted. Good fit of modeled vs measured quenched rates was demonstrated for simple die shapes. The models predict well the phase transformation products from the quench. There is good fit between predicted and measured distortion contours; however magnitude of predicted distortion and residual stresses does not match well the measured values. Further fine tuning of the model is required.

Wallace, J.F.; Schwam, D. [Case Western Reserve Univ., Cleveland, OH (United States)

1995-03-01

58

Steel Microstructure Effect on Mechanical Properties and Corrosion Behavior of High Strength Low Carbon Steel  

NASA Astrophysics Data System (ADS)

Different thermomechanical treatments were applied to a high strength low carbon steel with a novel chemical composition. As a result, three different microstructures were produced with dissimilar mechanical and corrosion properties. Subsequently, a tempering heat treatment was applied to redistribute the phases in the steel. Microstructure A with 56 pct martensite and 32 pct bainite presented high strength but medium ductility; microstructure C with 95 pct ferrite and 3 pct martensite/austenite resulted in low strength and high ductility, and finally microstructure B with 98 pct bainite and 2 pct martensite/austenite resulted in high strength and ductility. Alternatively the corrosion behavior obtained by polarization curves was characterized in 0.1 M H2SO4, 3 M H2SO4, 3.5 wt pct NaCl, and NS4 solutions resulting in similar magnitudes, while the corrosion behavior acquired by electrochemical impedance spectroscopy had slightly differences in 3 M H2SO4.

Barraza-Fierro, Jesus Israel; Campillo-Illanes, Bernardo; Li, Ximing; Castaneda, Homero

2014-08-01

59

Evolution of Microstructure and Mechanical Properties of Thermomechanically Processed Ultrahigh-Strength Steel  

Microsoft Academic Search

In the present study, low carbon microalloyed ultrahigh-strength steel was manufactured on a pilot scale. Transformation of\\u000a the aforesaid steel during continuous cooling was assessed. The steel sample was thermomechanically processed followed by\\u000a air cooling and water quenching. Variation in microstructure and mechanical properties at different finish rolling temperatures\\u000a (FRTs) was studied. A mixture of granular bainite and bainitic ferrite

P. S. Bandyopadhyay; S. K. Ghosh; S. Kundu; S. Chatterjee

2011-01-01

60

Friction Properties of Molybdenum Alloyed Steel at Elevated Temperatures  

SciTech Connect

The high-temperature properties of steel surface can be improved by molybdenum surface alloying. Molybdenzing was carried out on carbon steel in the multi-function double glow plasma surface alloying furnace. The friction and wear tests were conducted on a high temperature ball-on-disk tribometer under the temperature of 25 deg. C{approx}600 deg. C. The contents of alloy element varied with alloyed layer were detected by SEM attached with EDS. The molybdenized layer is composed of the deposited layer and diffused layer. The micro-hardness of alloyed layer decreases from HV650 on the top layer to HV240. The friction coefficient of molybdenized layer decreases from 0.5{approx}0.6 to 0.2{approx}0.3 and wear rate decreases by 20% at elevated temperature after molybdenizing.

Li Jianliang; Xiong Dangsheng [Department of Material Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094 (China); Wu Hongyan [College of Math and Physics, Nanjing University of Information and Technology, Nanjing, 210044 (China)

2011-01-17

61

HYDROGEN EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF FORGED STAINLESS STEELS  

SciTech Connect

The effect of hydrogen on the fracture toughness properties of Types 304L, 316L and 21-6-9 forged stainless steels was investigated. Fracture toughness samples were fabricated from forward-extruded forgings. Samples were uniformly saturated with hydrogen after exposure to hydrogen gas at 34 MPa or 69 and 623 K prior to testing. The fracture toughness properties were characterized by measuring the J-R behavior at ambient temperature in air. The results show that the hydrogen-charged steels have fracture toughness values that were about 50-60% of the values measured for the unexposed steels. The reduction in fracture toughness was accompanied by a change in fracture appearance. Both uncharged and hydrogen-charged samples failed by microvoid nucleation and coalescence, but the fracture surfaces of the hydrogen-charged steels had smaller microvoids. Type 316L stainless steel had the highest fracture toughness properties and the greatest resistance to hydrogen degradation.

Morgan, M

2008-03-28

62

Estimation Model for Magnetic Properties of Stamped Electrical Steel Sheet  

NASA Astrophysics Data System (ADS)

Less deterioration in magnetic properties of electrical steel sheets in the process of stamping out iron-core are necessary in order to maintain its performance. First, the influence of plastic strain and stress on magnetic properties was studied by test pieces, in which plastic strain was added uniformly and residual stress was not induced. Because the influence of plastic strain was expressed by equivalent plastic strain, at each equivalent plastic strain state the influence of load stress was investigated. Secondly, elastic limit was determined about 60% of macroscopic yield point (MYP), and it was found to agree with stress limit inducing irreversible deterioration in magnetic properties. Therefore simulation models, where beyond elastic limit plastic deformation begins and magnetic properties are deteriorated steeply, are proposed. Besides considered points in the deformation analysis are strain-rate sensitivity of flow stress, anisotropy under deformation, and influence of stress triaxiality on fracture. Finally, proposed models have been shown to be valid, because magnetic properties of 5mm width rectangular sheets stamped out from non-oriented electrical steel sheet (35A250 JIS grade) can be estimated with good accuracy. It is concluded that the elastic limit must be taken into account in both stamping process simulation and magnetic field calculation.

Kashiwara, Yoshiyuki; Fujimura, Hiroshi; Okamura, Kazuo; Imanishi, Kenji; Yashiki, Hiroyoshi

63

Magnetic properties and internal friction of iron carbide powder steels  

Microsoft Academic Search

The effect of the carbon content and the density on the magnetic properties and internal friction of iron carbide baked powder steels is investigated. It is shown that for a separate determination of the carbon content and the density of baked steels one needs to use the coercive force and the velocity of propagation of oscillations or the natural resonance

A. V. Zagainov; E. S. Gorkunov

1995-01-01

64

Influence of sintering parameters on the properties of duplex stainless steel  

Microsoft Academic Search

Purpose: of this paper was to examine the influence of sintering parameters like time, temperature, atmosphere and gas pressure under cooling stage on the mechanical properties of duplex stainless steels. Design\\/methodology\\/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, martensitic base powders by controlled addition of alloying elements, such as Cr, Ni, Mo and

L. A. Dobrza?ski a; Z. Brytan; M. Actis Grande; M. Rosso

65

The mechanical properties of stainless maraging steels  

Microsoft Academic Search

1.Maraging Cr-Ni-Mo-Ti steels with around 1% Ti have good ductility and are not susceptible to cracks at high strength levels. These steels are not susceptible to slow fracture in water on prolonged application of static loads close to the ultimate strength and have a high resistance to low-cycle fatigue. In the quenched condition, with the strength ~100 kg\\/mm2, the steels

E. S. Kagan; Ya. M. Potak; V. V. Sachkov

1969-01-01

66

Influence of carbide and inclusion contents on the fatigue properties of high speed steels and tool steels  

Microsoft Academic Search

In this study the influence of carbide distribution, inclusion contents and the surface machining process on the fatigue properties of tool steels and high speed steels were investigated. Four different steels intended for cold work applications were included, of which three were powder metallurgically processed and one was conventionally ingot cast. One of the powder metallurgy steels was studied in

Fredrik Meurling; Arne Melander; Magnus Tidesten; Leif Westin

2001-01-01

67

Properties of formable high strength sheet steels for automotive use  

SciTech Connect

Metallurgical factors affecting the press formability of the newly developed high strength sheet steels have been discussed. Dual phase steels, CHLY (cold-rolled sheet steel) and HTP-D (as-hotrolled sheet steel), produced by control of cooling conditions after intercritical annealing or hot-rolling exhibit very low yield to tensile strength ratio and high n-value. Rephosphorized extralow carbon steel, CHRX, produced by continuous annealing with rapid cooling is characterized by its extremely high r-value and low yield strength. CHLY, HTP-D and CHRX have large bake hardenability. Precipitation hardened steel, HTP-F (hot-rolled sheel steel), produced by adjusting carbon equivalent and sulfur content is suitable for manufacturing wheel rims owing to its good formability after flash butt welding.

Satoh, S.; Kato, T.; Nishida, M.; Obara, T.; Shinozaki, M.; Tosaka, A.

1983-11-01

68

Spray forming high speed steelproperties and processing  

Microsoft Academic Search

The potential of spray forming (SF) for microstructural refining can be attractive to the production of high speed steels. The refined as-cast structure may lead to important improvements of material properties, compared to conventionally cast materials. The present work aimed to compare the properties of AISI M3:2 high speed steel produced through spray forming and conventional casting. Also, the processing

Rafael Agnelli Mesquita; Celso Antonio Barbosa

2004-01-01

69

Research Concerning The Mechanical And Structural Properties Of Warm Rolled Construction Carbon Steels  

SciTech Connect

Construction carbon steels represent an important steel class due to the large quantity in which it is produced. Generally, these steels are delivered in as-rolled or normalized condition heaving a ferrite-pearlite microstructure. For a given chemical composition, the mechanical characteristics of this microstructure are largely influenced by the grain size. Rolling is the deformation process which is most widely used for grain size refinement. Situated in the intermediate temperature range, warm-rolling presents certain advantages as compared to classical hot- or cold-working processes.The paper presents a study on the microstructure and mechanical properties of Ck15 carbon steel samples warm-rolled. After deformation, the microstructure was investigated by light microscopy. Hardness measurements were made on the section parallel to the rolling direction. The mechanical properties of the steel after warm-rolling were assessed by tensile and impact tests. Additional information concerning the fracture behavior of warm-rolled samples was obtained by examining the fracture surface by scanning electron microscopy. The microstructure of the steel proved to have good mechanical properties. By considering the technologic and energy aspects, the paper shows that warm-rolling can lead to the improvement of mechanical properties of construction carbon steels.

Medrea, C. [Technological Educational Institute of Piraeus, Depmartment of Physics, Chemistry and Materials Technology, 250 Thivon and P. Ralli Str, 12244, Aigaleo, Athens (Greece); Negrea, G.; Domsa, S. [Technical University of Cluj-Napoca, Faculty of Materials Science and Engineering, Cluj-Napoca (Romania)

2007-04-07

70

The effect of intercritical heat treatment on the mechanical properties of AISI 3115 steel  

Microsoft Academic Search

This paper presents the effect of intercritical heat treatment (IHT) on the mechanical properties of AISI 3115 alloy steel. The steel was intercritically heat-treated at a temperature range of 730830C followed by water quenching. The properties of tensile strength, fatigue, hardness and microstructure were evaluated from the mechanical tests and metallographic analysis, respectively. The experimental results showed that tensile strength

M. A. Maleque; Y. M. Poon; H. H. Masjuki

2004-01-01

71

Measurement of the dynamic mechanical properties of high-strength steel using wave propagation characteristics  

NASA Astrophysics Data System (ADS)

The dynamic mechanical properties of different high-strength steels were measured and compared based on their respective microstructures. Beam-shaped test specimens were excited using an electric shaker while vibration responses were measured using a non-contact laser sensor. Flexural wave propagation was analyzed to precisely determine material damping. Measured properties were compared to those of carbon steels. In addition, the effects of grain size determined by optical micrographs on the dynamic properties were investigated. The influence of the tensile strength on the measured properties was analyzed. The high-strength steels exhibited smaller damping with a similar Young's modulus compared to carbon steels, although the tensile strength was much greater.

Park, Jeongwon; Kim, Do-Hyung; Kim, Hak-Sung; Park, Junhong; Yoo, Ji Woo

2014-06-01

72

Dynamic nanomechanical properties of novel Si-rich intermetallic coatings growth on a medical 316 LVM steel by hot dipping in a hypereutectic Al-25Si alloy.  

PubMed

This aim of this study is to determine the elastoplastic properties of Ni-free Al3FeSi2 intermetallic coatings grown on medical stainless steel under different experimental conditions. Elastoplastic properties are defined by the plasticity index (PI), which correlates the hardness and the Young?s modulus. Special emphasis is devoted to correlate the PI with the wear resistance under sliding contact, determined by scratch testing, and fracture toughness, determined by using a novel method based on successive impacts with small loads. With regard to the substrate, the developed coatings are harder and exhibit a lower Young?s reduced modulus, irrespective of the experimental conditions. It has been shown that preheating of the samples prior to hot dipping and immersion influences the type and volume fraction of precipitates, which in turn also affect the nanomechanical properties. The higher the preheating temperature is, the greater the Young?s reduced modulus is. For a given preheating condition, an increase of the immersion time yields a decrease in hardness. Although apparent friction coefficients of coated specimens are smaller than those obtained on AISI 316 LVM, they increase when using preheating or higher immersion times during processing, which correlates with the PI. The presence of precipitates produces an increase in fracture toughness, with values greater than those presented by samples processed on melted AlSi alloys with lower Si content (12wt%). Therefore, these intermetallic coatings could be considered "hard but tough", suitable to enhance the wear resistance, especially when using short periods of immersion. PMID:25778350

Frutos, E; Gonzlez-Carrasco, J L

2015-06-01

73

Improvements in microstructure homogenization and mechanical properties of diffusion-alloyed steel compact by the addition of Cr-containing powders  

Microsoft Academic Search

The use of diffusion-alloyed powders for fabricating powder metal parts, despite alleviating the segregation problem of the\\u000a alloying elements while retaining good compressibility, still cannot attain homogeneous microstructure in as-sintered products.\\u000a The presence of soft Ni-rich areas and pores causes poor mechanical properties compared to those of wrought steel counterparts.\\u000a This study investigated the effects of adding 0.5 wt pct

M. W. Wu; K. S. Hwang; H. S. Huang; K. S. Narasimhan

2006-01-01

74

The influence of assist gas on magnetic properties of electrotechnical steel sheets cut with laser  

NASA Astrophysics Data System (ADS)

The paper presents the influence of assist gas (air and nitrogen) during laser cutting on magnetization, magnetic permeability and loss characteristics of non-oriented electrical steels. The research was made on an non-oriented M330-50A grade electrical steels by means of single sheet tester. In order to enhance the effect of cutting and the same degradation zone on magnetic properties, strips with different width were achieved. Measurements results indicate that application of air as assist gas has more destructive effect on magnetic properties of electrical steels than nitrogen one.

Gaworska-Koniarek, Dominika; Szubzda, Bronis?aw; Wilczy?ski, Wies?aw; Drosik, Jerzy; Kara?, Kazimierz

2011-07-01

75

Influence of original microstructure on the transformation behavior and mechanical properties of ultra-high-strength TRIP-aided steel  

NASA Astrophysics Data System (ADS)

The transformation behavior and tensile properties of an ultra-high-strength transformation-induced plasticity (TRIP) steel (0.2C-2.0Si-1.8Mn) were investigated by different heat treatments for automobile applications. The results show that F-TRIP steel, a traditional TRIP steel containing as-cold-rolled ferrite and pearlite as the original microstructure, consists of equiaxed grains of intercritical ferrite surrounded by discrete particles of M/RA and B. In contrast, M-TRIP steel, a modified TRIP-aided steel with martensite as the original microstructure, containing full martensite as the original microstructure is comprised of lath-shaped grains of ferrite separated by lath-shaped martensite/retained austenite and bainite. Most of the austenite in F-TRIP steel is granular, while the austenite in M-TRIP steel is lath-shaped. The volume fraction of the retained austenite as well as its carbon content is lower in F-TRIP steel than in M-TRIP steel, and austenite grains in M-TRIP steel are much finer than those in F-TRIP steel. Therefore, M-TRIP steel was concluded to have a higher austenite stability, resulting in a lower transformation rate and consequently contributing to a higher elongation compared to F-TRIP steel. Work hardening behavior is also discussed for both types of steel.

Yin, Hong-xiang; Zhao, Ai-min; Zhao, Zheng-zhi; Li, Xiao; Li, Shuang-jiao; Hu, Han-jiang; Xia, Wei-guang

2015-03-01

76

Hydrogen Effect on Nanomechanical Properties of the Nitrided Steel  

NASA Astrophysics Data System (ADS)

In situ electrochemical nanoindentation is used to examine the effect of electrochemically charged hydrogen on mechanical properties of the nitride layer on low-alloy 2.25Cr-1Mo martensitic structural steel. By application of this method, we were able to trace the changes in the mechanical properties due to the absorption of atomic hydrogen to different depths within the compound and diffusion layers. The results clearly show that the hydrogen charging of the nitriding layer can soften the layer and reduce the hardness within both the compound and the diffusion layers. The effect is completely reversible and by removal of the hydrogen, the hardness recovers to its original value. The reduction in hardness of the nitride layer does not correlate to the nitrogen concentration, but it seems to be influenced by the microstructure and residual stress within the compound and diffusion layers. Findings show that nitriding can be a promising way to control the hydrogen embrittlement of the tempered martensitic steels.

Barnoush, Afrooz; Asgari, Masoud; Johnsen, Roy; Hoel, Rune

2013-02-01

77

Recrystallization and magnetic properties of purified 3% silicon steels  

Microsoft Academic Search

The effect of impurities on the tertiary recrystallization and magnetic properties of the thin (10 to 100 ?m) silicon steels was investigated. For purification, the conventional grain oriented silicon steels, which were used as starting materials with a thickness of 0.30 mm were pre-annealed at 1200 C in a vacuum of 110?3 Pa before cold rolling. In sheets without pre-annealing,

K. Ishiyama; K. I. Arai; T. Honda

1991-01-01

78

Mechanical properties of structural amorphous steels: Intrinsic correlations, conflicts, and optimizing strategies  

NASA Astrophysics Data System (ADS)

Amorphous steels have demonstrated superior properties and great potentials for structural applications since their emergence, yet it still remains unclear about how and why their mechanical properties are correlated with other factors and how to achieve intended properties by designing their compositions. Here, the intrinsic interdependences among the mechanical, thermal, and elastic properties of various amorphous steels are systematically elucidated and a general trade-off relation is exposed between the strength and ductility/toughness. Encouragingly, a breakthrough is achievable that the strength and ductility/toughness can be simultaneously improved by tuning the compositions. The composition dependences of the properties and alloying effects are further analyzed thoroughly and interpreted from the fundamental plastic flow and atomic bonding characters. Most importantly, systematic strategies are outlined for optimizing the mechanical properties of the amorphous steels. The study may help establish the intrinsic correlations among the compositions, atomic structures, and properties of the amorphous steels, and provide useful guidance for their alloy design and property optimization. Thus, it is believed to have implications for the development and applications of the structural amorphous steels.

Liu, Z. Q.; Zhang, Z. F.

2013-12-01

79

Mechanical properties of structural amorphous steels: Intrinsic correlations, conflicts, and optimizing strategies  

SciTech Connect

Amorphous steels have demonstrated superior properties and great potentials for structural applications since their emergence, yet it still remains unclear about how and why their mechanical properties are correlated with other factors and how to achieve intended properties by designing their compositions. Here, the intrinsic interdependences among the mechanical, thermal, and elastic properties of various amorphous steels are systematically elucidated and a general trade-off relation is exposed between the strength and ductility/toughness. Encouragingly, a breakthrough is achievable that the strength and ductility/toughness can be simultaneously improved by tuning the compositions. The composition dependences of the properties and alloying effects are further analyzed thoroughly and interpreted from the fundamental plastic flow and atomic bonding characters. Most importantly, systematic strategies are outlined for optimizing the mechanical properties of the amorphous steels. The study may help establish the intrinsic correlations among the compositions, atomic structures, and properties of the amorphous steels, and provide useful guidance for their alloy design and property optimization. Thus, it is believed to have implications for the development and applications of the structural amorphous steels.

Liu, Z. Q., E-mail: liuzq@imr.ac.cn; Zhang, Z. F., E-mail: zhfzhang@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

2013-12-28

80

Improved Life of Die Casting Dies of H13 Steel by Attaining Improved Mechanical Properties and Distortion Control During Heat Treatment  

SciTech Connect

The ultimate goal of this project is to increase die casting die life by using fast enough quenching rates to obtain good toughness and fatigue resistance in premium grade H-13 steel dies. The main tasks of the project were to compile a database on physical and mechanical properties of H-13; conduct gas quenching experiments to determine cooling rates of dies in difference vacuum furnaces; measure the as-quenched distortion of dies and the residual stresses; generate finite element analysis models to predict cooling rates, distortion, and residual stress of gas quenched dies; and establish rules and create PC-based expert system for prediction of cooling rates, distortion, and residual stress in vacuum/gas quenched H-13 dies. Cooling curves during gas quenching of H-13 blocks and die shapes have been measured under a variety of gas pressure. Dimensional changes caused by the gas quenching processes have been determined by accurate mapping of all surfaces with coordinate measuring machines before and after the quench. Residual stresses were determined by the ASTM E837 hole-drilling strain gage method. To facilitate the computer modeling work, a comprehensive database of H-13 mechanical and physical properties has been compiled. Finite element analysis of the heat treated shapes has been conducted using the TRAST/ABAQUS codes. There is a good fit between the predicted and measured distortion contours. However, the magnitude of the predicted distortion and residual stresses does not match well the measured values. Further fine tuning of the model is required before it can be used to predict distortion and residual stress in a quantitative manner. This last step is a prerequisite to generating rules for a reliable expert system.

J. F. Wallace; D. Schwam

1998-10-01

81

Weld Properties of a Free Machining Stainless Steel  

SciTech Connect

The all weld metal tensile properties from gas tungsten arc and electron beam welds in free machining austenitic stainless steels have been determined. Ten heats with sulfur contents from 0.04 to 0.4 wt.% and a wide range in Creq/Nieq ratios were studied. Tensile properties of welds with both processes were related to alloy composition and solidification microstructure. The yield and ultimate tensile strengths increased with increasing Creq/Nieq ratios and ferrite content, whereas the ductility measured by RA at fracture decreased with sulfur content. Nevertheless, a range in alloy compositions was identified that provided a good combination of both strength and ductility. The solidification cracking response for the same large range of compositions are discussed, and compositions identified that would be expected to provide good performance in welded applications.

J. A. Brooks; S. H. Goods; C. V. Robino

2000-08-01

82

Structure and properties of high-temperature austenitic steels for superheater tubes  

NASA Astrophysics Data System (ADS)

The structure and properties of high-temperature austenitic steels intended for superheater tubes are analyzed. Widely used Kh18N10T (AISI 304) and Kh16N13M3 (AISI 316) steels are found not to ensure a stable austenitic structure and stable properties during long-term thermal holding under stresses. The hardening of austenitic steels by fine particles of vanadium and niobium carbides and nitrides and ?'-phase and Fe2W and Fe2Mo Laves phase intermetallics is considered. The role of Cr23C6 chromium carbides, the ? phase, and coarse precipitates of an M 3B2 phase and a boron-containing eutectic in decreasing the time to failure and the stress-rupture strength of austenitic steels is established. The mechanism of increasing the stress-rupture strength of steels by boron additions is described. The chemical compositions, mechanical properties, stress-rupture strength, and creep characteristics of Russian and foreign austenitic steels used or designed for superheater tubes intended for operation under stress conditions at temperatures above 600C are presented. The conditions are found for increasing the strength, plasticity, and thermodeformation stability of austenite in steels intended for superheater tubes operating at 700C under high stresses for a long time.

Blinov, V. M.

2009-12-01

83

Effects of elemental Sn on the properties and inclusions of the free-cutting steel  

NASA Astrophysics Data System (ADS)

A new environment-friendly free-cutting steel alloyed with elemental Sn (Y20Sn) was developed to meet the requirements of machinability and mechanical properties according to GB/T87311988. The machinability of the steel is enhanced by the segregation of elemental Sn at grain boundaries. The effect of Sn segregation on intergranular brittle fracture at normal cutting temperature from 250C to 400C is confirmed. The formation mechanism of main inclusions MnS is influenced by the presence of Sn and the attachment of Sn around MnS itself as a surfactant, and this mechanism also explains the improvement in machinability and mechanical properties of the steel. In the steel, the relevant inclusions are mainly spherical or axiolitic, and are uniformly distributed in small volume. Such inclusions improve the machinability of the steel and do not impair the mechanical properties as well. Experimental results demonstrate that the appropriate content of Sn in the steel is 0.03wt% to 0.08wt%, and the remaining composition is close to that of standard Y20 steel.

Chen, Shao-chun; Zhu, Rong; Xue, Li-qiu; Lin, Teng-chang; Li, Jing-she; Lin, Yang

2015-02-01

84

Influence of thermal aging on microstructure and mechanical properties of CLAM steel  

NASA Astrophysics Data System (ADS)

In order to investigate the influence of thermal aging on microstructure and mechanical properties of CLAM (China low activation martensitic) steel, a comparison study was made on the as-tempered and the aged steels. The tempered CLAM steels were subjected to aging treatment at 600 C for 1100 h and 3000 h, and at 650 C for 1100 h, respectively. The changes of microstructure were characterized by both transmission electron microscope (TEM) and scanning electron microscope (SEM). The mechanical properties were evaluated by Charpy impact, tensile and Vickers hardness tests. The upper shelf energy (USE) of the thermal aged CLAM steel decreased with the extension of aging time, while the yield strength changed slightly. After long-term thermal aging, the MX type precipitates remained stable. The coarsening of M23C6 and the formation of Laves phase were confirmed by scanning/transmission electron microscopes. The Laves phase was the main factor leading to the increase of DBTT.

Huang, Lixin; Hu, Xue; Yang, Chunguang; Yan, Wei; Xiao, Furen; Shan, Yiyin; Yang, Ke

2013-11-01

85

Influence of tensile stress on permeability properties of type 304 stainless steel  

NASA Astrophysics Data System (ADS)

The permeability properties of type SUS304 stainless steel (SUS304 steel) were evaluated under different values of tensile stress using the electromagnetic impedance method. The impedance-magnetic-field curve of SUS304 steel, which corresponds to the permeability-magnetic field-curve, was measured under tensile stresses of 0, 70, and 140 MPa for specimens subjected to prestrains of 5% to 40% to change the martensite fraction. The impedance curves were measured in the length (tensile) direction and the width direction. The results showed that the tensile direction was the magnetic hard axis of the martensite phase in SUS304 steel. The applied stress sensitivity of the permeability in SUS304 steel was affected by the volume fraction, residual stress, stress distribution according to the orientation angle of the martensite phase, and their interactions.

Kinoshita, K.

2015-05-01

86

Mechanical Properties of Structural Steels in Hydrogen  

E-print Network

of structural steels in hydrogen d/dt > 0 d/dt > 0 strength of materials: UTS, YS, f, RA H2HH H H2 H H2 H H2 H.01 strength ­ 96 ksi (662 MPa) in longitudinal orientation ­ 114 ksi Loading bolt Load cell 13 mm strain gage leads (Excitation and DAQ) Load(P) Po Ko PTH KTH incubation

87

The effect of equal channel angular extrusion on the microstructure and mechanical properties of AISI 1552, AISI 4340, and A2 tool steels  

E-print Network

In this investigation, Austenitized AISI 4340 and A2 tool steel were ausformed using ECAE as a sole deformation mechanism. In addition, AISI 1552 steel was deformed by ECAE. The effect of deformation on hardness, tensile properties...

Shadat, Mohammed Anower

1998-01-01

88

Effect of Heat Treatment on the Microstructure and Mechanical Properties of Stainless Steel 316L Coatings Produced by Cold Spray for Biomedical Applications  

NASA Astrophysics Data System (ADS)

In this study, the effects of heat treatment on the microstructure and mechanical properties of cold sprayed stainless steel 316L coatings using N2 and He as propellant gases were investigated. Powder and coating characterizations, including coating microhardness, coating porosity, and XRD phase analysis were performed. It was found that heat treatment reduced porosity, improved inter-particle bonding, and increased ductility. XRD results confirmed that no phase transformation occurred during deposition. Significant increase in UTS and ductility was observed for the annealed specimens obtained with nitrogen propellant, whereas little changes were observed for the helium propellant produced specimen.

AL-Mangour, Bandar; Vo, Phuong; Mongrain, Rosaire; Irissou, Eric; Yue, Stephen

2014-04-01

89

Steel Reoxidation by Gunning Mass and Tundish Slag  

NASA Astrophysics Data System (ADS)

Steel reoxidation in the tundish has a significant influence on the steel cleanliness and therefore on the mechanical properties of the final product. In the present work, the steel reoxidation by two types of gunning mass (GM), viz. magnesia- and alumina-based GM, and two types of tundish slag, viz. lime-alumina-silica and lime-alumina slags, has been investigated. The evolution of the steel composition during the test was analyzed and predicted based on thermodynamic and kinetic considerations. The calculated steel composition agrees well with measured values, when assuming the mass transfer in slag phase limits the reoxidation reactions. The oxidation capacity of the gunning mass and tundish slag is quantified by calculating the oxygen amount supplied from the GM and the slag to the steel phase. It was found that compared to alumina GM, magnesia GM exhibits a stronger oxidation capacity due to its higher content of reducible oxides (10 wt pct SiO2 + 6 wt pct FeO). Compared to lime-alumina-silica tundish slag, lime-alumina slag (with more FeO + MnO contents) provides more oxygen to the molten steel in the present experimental conditions and consequently shows a stronger oxidation capacity.

Yan, Pengcheng; Arnout, Sander; Van Ende, Marie-Aline; Zinngrebe, Enno; Jones, Tom; Blanpain, Bart; Guo, Muxing

2015-01-01

90

Cleavage fracture properties of high strength steel weldments  

SciTech Connect

The qualification of consumables and welding of steels in critical naval applications, including submarine construction, is dependent upon the achievement of high levels of toughness at low temperature. The principal technique employed is the Charpy impact test at temperatures down to {minus}115 C ({minus}175 F). In the investigation described here, low temperature toughness properties were investigated by breaking notched specimens in slow four point bending and measuring the critical tensile stress for cleavage initiation. Multi-pass Flux Cored Arc (FCA) welds joining 690 MPa (100 ksi) yield strength, quenched and tempered steel were tested to identify cleavage fracture micromechanisms and to investigate the role of microstructural features in the cleavage fracture process. Cleavage fracture stress values in the range 2,018 to 2,381 MPa were recorded in weld metal when testing at sub-zero temperatures. Detailed examination of fracture surfaces by scanning electron microscope (SEM) revealed that weld metal inclusions play a critical role in acting as cleavage initiation sites. Changing welding position from downhand to vertical-up resulted in a small number of widely spaced inclusions approaching or exceeding 10 {micro}m in diameter but these were not observed to act as cleavage initiation sites. The cleavage fracture resistance of multi-pass Manual Metal Arc (MMA) welds which are currently under investigation is compared with FCA weldments.

Hughes, R.K.; Ritter, J.C. [DSTO Aeronautical and Maritime Research Lab., Melbourne (Australia)

1996-12-31

91

Antibacterial properties, corrosion resistance and mechanical properties of Cu-modified SUS 304 stainless steel  

Microsoft Academic Search

This investigation studies the effects of Cu content and ageing treatment on the microstructural, mechanical, corrosion and antibacterial properties of SUS 304 austenitic stainless steel. Cu was added respectively to SUS 304 stainless steels in proportions of 1.5, 2.5, 3.5, 4.5 and 5.5wt.%. A vacuum arc remelting furnace was used to remelt SUS 304 stainless steel with various added Cu

I. T. Hong; C. H. Koo

2005-01-01

92

Steel casting by diffusion solidification  

Microsoft Academic Search

A new process for casting and welding carbon steels is described in which carbon diffuses isothermally or adiabatically within\\u000a an intimate mixture of solid low carbon steel and high carbon liquid iron to effect solidification and subsequent homogenization\\u000a with respect to carbon. Advantages over conventional casting processes and products result from 1) 150 to 200C lower casting\\u000a temperature; 2) reduced

George Langford; Robert E. Cunningham

1978-01-01

93

Tensile properties of welded helium charged 304L stainless steel  

NASA Astrophysics Data System (ADS)

The room-temperature tensile properties of helium-containing 304L stainless steel subjected to thermal cycles simulating fusion welding conditions have been measured. Helium was introduced into tensile specimens by tritium charging, and aged to generate 526 appm 3He by radioactive decay. The specimens were then vacuum annealed to remove the tritium. The helium-charged samples were subjected to transient thermal cycles simulating those occurring in the heat affected zone of a gas tungsten arc weld. Peak temperatures above 1073 K caused severe ductility losses, fracture mode changes (from ductile transgranular rupture to ductile intergranular fracture), and losses in ultimate tensile strength. These effects are attributed to helium redistribution and void growth on the grain boundary. Subsequently, grain boundary failure occurs during tensile testing because of the large quantity of trapped helium on the boundary.

Robinson, S. L.

1988-05-01

94

46 CFR 54.25-20 - Low temperature operation-ferritic steels with properties enhanced by heat treatment (modifies...  

Code of Federal Regulations, 2013 CFR

...specification and shall be suitable for the design stress levels adopted. The service temperature...and of fracture appearance in percentage shear, which are recorded for information...permitted by 54.05-30, the allowable stress values may not exceed those given...

2013-10-01

95

46 CFR 54.25-20 - Low temperature operation-ferritic steels with properties enhanced by heat treatment (modifies...  

Code of Federal Regulations, 2011 CFR

...specification and shall be suitable for the design stress levels adopted. The service temperature...and of fracture appearance in percentage shear, which are recorded for information...permitted by 54.05-30, the allowable stress values may not exceed those given...

2011-10-01

96

46 CFR 54.25-20 - Low temperature operation-ferritic steels with properties enhanced by heat treatment (modifies...  

Code of Federal Regulations, 2014 CFR

...specification and shall be suitable for the design stress levels adopted. The service temperature...and of fracture appearance in percentage shear, which are recorded for information...permitted by 54.05-30, the allowable stress values may not exceed those given...

2014-10-01

97

46 CFR 54.25-20 - Low temperature operation-ferritic steels with properties enhanced by heat treatment (modifies...  

Code of Federal Regulations, 2012 CFR

...specification and shall be suitable for the design stress levels adopted. The service temperature...and of fracture appearance in percentage shear, which are recorded for information...permitted by 54.05-30, the allowable stress values may not exceed those given...

2012-10-01

98

Microstructure and Corrosion Properties of AlCoCrFeNi High Entropy Alloy Coatings Deposited on AISI 1045 Steel by the Electrospark Process  

NASA Astrophysics Data System (ADS)

Electrospark deposition (ESD) was employed to clad the AlCoCrFeNi high-entropy alloy (HEA) on AISI 1045 carbon steel. The relationship between the microstructure and corrosion properties of the HEA-coated specimens was studied and compared with that of the copper-molded cast HEA material. Two major microstructural differences were found between the cast HEA material and the HEA coatings. First, the cast material comprises both columnar and equiaxed crystals with a columnar-to-equiaxed transition (CET), whereas the HEA coatings consist of an entirely columnar crystal structure. The CET phenomenon was analyzed based on Hunt's criterion. Second, unlike the cast HEA material, there was no obvious Cr-rich interdendritic segregation and nano-sized precipitate distributed within the dendrites of the HEA coating. With regard to corrosion properties, the corrosion current of the HEA-coated specimen was significantly lower than for the 1045 steel and the cast HEA material. This was attributed to the ESD specimen having a relatively high Cr oxide and Al oxide content at the surface. Moreover, for the ESD specimen, the absence of Cr-rich interdendritic phase and second-phase precipitation resulted in a relatively uniform corrosion attack, which is different from the severe galvanic corrosion attack that occurred in the cast specimen.

Li, Q. H.; Yue, T. M.; Guo, Z. N.; Lin, X.

2013-04-01

99

IRRADIATION CREEP AND MECHANICAL PROPERTIES OF TWO FERRITIC-MARTENSITIC STEELS IRRADIATED IN THE BN-350 FAST REACTOR  

SciTech Connect

Russian ferritic/martensitic steels EP-450 and EP-823 were irradiated to 20-60 dpa in the BN-350 fast reactor in the form of pressurized creep tubes and small rings used for mechanical property tests. Data derived from these steels serves to enhance our understanding of the general behavior of this class of steels. It appears that these steels exhibit behavior that is very consistent with that of Western steels. Swelling is relatively low at high neutron exposure and confined to temperatures less then 420 degrees C, but may be camouflaged somewhat by precipitation-related densification. The irradiation creep studies confirm that the creep compliance of F/M steels is about one-half that of austenitic steels, and that the loss of strength at test temperatures above 500 degrees C is a problem generic to all F/M steels. This conclusion is supported by post-irradiation measurement of short-term mechanical properties. At temperatures below 500 degrees C both steels retain their high strength (yield stress 0.2=550-600 MPa), but at higher test temperatures a sharp decrease of strength properties occurs. However, the irradiated steels still retain high post-irradiation ductility at test temperatures in the range of 20-700 degrees C.

Porollo, S. I.; Konobeev, Yu V.; Dvoriashin, A. M.; Budylkin, N. I.; Mironova, E. G.; Leontyeva-Smirnova, M. V.; Loltukhovsky, A. G.; Bochvar, A. A.; Garner, Francis A.

2002-09-01

100

MICROSTRUCTURE AND MECHANICAL PROPERTY PERFORMANCE OF COMMERCIAL GRADE API PIPELINE STEELS IN HIGH PRESSURE GASEOUS HYDROGEN  

SciTech Connect

The continued growth of the world s developing countries has placed an ever increasing demand on traditional fossil fuel energy sources. This development has lead to increasing research and development of alternative energy sources. Hydrogen gas is one of the potential alternative energy sources under development. Currently the most economical method of transporting large quantities of hydrogen gas is through steel pipelines. It is well known that hydrogen embrittlement has the potential to degrade steel s mechanical properties when hydrogen migrates into the steel matrix. Consequently, the current pipeline infrastructure used in hydrogen transport is typically operated in a conservative fashion. This operational practice is not conducive to economical movement of significant volumes of hydrogen gas as an alternative to fossil fuels. The degradation of the mechanical properties of steels in hydrogen service is known to depend on the microstructure of the steel. Understanding the levels of mechanical property degradation of a given microstructure when exposed to hydrogen gas under pressure can be used to evaluate the suitability of the existing pipeline infrastructure for hydrogen service and guide alloy and microstructure design for new hydrogen pipeline infrastructure. To this end, the 2 Copyright 2010 by ASME microstructures of relevant steels and their mechanical properties in relevant gaseous hydrogen environments must be fully characterized to establish suitability for transporting hydrogen. A project to evaluate four commercially available pipeline steels alloy/microstructure performance in the presences of gaseous hydrogen has been funded by the US Department of Energy along with the private sector. The microstructures of four pipeline steels were characterized and then tensile testing was conducted in gaseous hydrogen and helium at pressures of 800, 1600 and 3000 psi. Based on measurements of reduction of area, two of the four steels that performed the best across the pressure range were selected for evaluation of fracture and fatigue performance in gaseous hydrogen at 800 and 3000 psi. This paper will describe the work performed on four commercially available pipeline steels in the presence of gaseous hydrogen at pressures relevant for transport in pipelines. Microstructures and mechanical property performances will be compared. In addition, recommendations for future work related to gaining a better understanding of steel pipeline performance in hydrogen service will be discussed.

Stalheim, Mr. Douglas [DGS Metallurgical Solutions Inc; Boggess, Todd [Secat; San Marchi, Chris [Sandia National Laboratories (SNL); Jansto, Steven [Reference Metals Company; Somerday, Dr. B [Sandia National Laboratories (SNL); Muralidharan, Govindarajan [ORNL; Sofronis, Prof. Petros [University of Illinois

2010-01-01

101

Microstructure and mechanical properties of quenched and tempered 300M steel  

NASA Technical Reports Server (NTRS)

Type 300M steel, which is being used for the landing gear on the space shuttle orbiter, was subjected to a wide range of quenched and tempered heat treatments. The plane-strain fracture toughness and the tensile ultimate and yield strengths were evaluated. Cryogenic mechanical properties were obtained for conventionally heat-treated steel. The microstructure of all heat-treated test coupons was studied both optically and by transmission electron microscopy. Fracture surfaces were studied by means of scanning electron microscopy. Results indicate that substantial improvement in toughness with no loss in strength can be accomplished in quenched and tempered steel by austenitizing at 1255 K or higher. Low fracture toughness in conventionally austenitized 300M steel (1144 K) appears to be caused by undissolved precipitates, seen both in the submicrostructure and on the fracture surface, which promote failure by quasi-cleavage. The precipitates appeared to dissolve in the range 1200 to 1255 K.

Youngblood, J. L.; Raghavan, M.

1978-01-01

102

Effect of Alloying Elements on Tensile Properties, Microstructure, and Corrosion Resistance of Reinforcing Bar Steel  

NASA Astrophysics Data System (ADS)

The effect of copper, phosphorus, and chromium present in a semikilled reinforcing bar steel produced by in-line quenching [thermomechanical treatment (TMT)] process on the tensile properties, microstructure, and corrosion resistance of steel in simulated chloride environment has been investigated. The results have been compared with that of a semikilled C-Mn reinforcing bar steel without these alloying elements produced by the same process route. Though the amount of phosphorus (0.11 wt.%) was higher than that specified by ASTM A 706 standard, the Cu-P-Cr steel exhibited a composite microstructure, and good balance of yield stress, tensile stress, elongation, and ultimate tensile to yield stress ratio. Two conventional test methods, namely, the salt fog, and potentiodynamic polarization tests, were used for the corrosion test. The rust formed on Cu-P-Cr steel was adherent, and was of multiple colors, while the corrosion products formed on the C-Mn steel were weakly adherent and relatively darker blue. Also, the free corrosion potential of the Cu-P-Cr steel was nobler, and the corrosion current was markedly lower than that of a C-Mn rebar. The Cu-P-Cr steel did not develop any pits/deep grooves on its surface even after the prolonged exposure to salt fog. The improved corrosion resistance of the Cu-P-Cr steel has been attributed to the presence of copper, phosphorus, and small amount of chromium in the dense, adherent rust layer on the surface of reinforcing steel bar. A schematic mechanism of charge transfer has been proposed to explain the improved corrosion resistance of the Cu-P-Cr alloyed TMT rebar.

Panigrahi, B. K.; Srikanth, S.; Sahoo, G.

2009-11-01

103

Author's personal copy Magnetic properties of stainless steels at room and cryogenic temperatures  

E-print Network

: Magnetic measurement Ferromagnetic property Stainless steel Martensitic Ferritic a b s t r a c t The magnetic properties of ten types of ferritic and martensitic stainless steels have been measured at room soft magnetic properties adequate for magnetic applications. The carbon content of the steels was found

Oxley, Paul

104

Effects of Aging Structures and Humidity on Fatigue Properties of Maraging Steel  

NASA Astrophysics Data System (ADS)

Effects of aging structures and humidity on fatigue properties of 350 grade 18% Ni maraging steel were investigated under rotating bending in relative humidity of 25% and 85%. Aging conditions tested were a conventional single aging and a double one which was aged at low temperature after the conventional aging. In each aging, under and peak aged steels were prepared. Tensile strength was increased by the double aging without reduction of the ductility. Proportional relation between fatigue limit and Vickers hardness held until 750HV in low humidity. However fatigue strength was largely decreased by high humidity, especially in the peak aged steel at the single aging. The decrease in fatigue strength by high humidity was mainly caused by the acceleration of a crack initiation due to the anodic dissolution. The acceleration of a crack initiation was larger in the steel peak aged at the single aging with larger precipitated particles.

Hayashi, Kousuke; Nagano, Takanori; Moriyama, Michihiko; Wang, Xishu; Kawagoishi, Norio

105

Mechanical property variation within Inconel 82\\/182 dissimilar metal weld between low alloy steel and 316 stainless steel  

Microsoft Academic Search

In several locations of pressurized water reactors, dissimilar metal welds using Inconel welding wires are used to join the low alloy steel components to stainless-steel pipes. Because of the existence of different materials and chemistry variation within welds, mechanical properties, such as tensile and fracture properties, are expected to show spatial variation. For design and integrity assessment of the dissimilar

Changheui Jang; Jounghoon Lee; Jong Sung Kim; Tae Eun Jin

2008-01-01

106

Mechanical properties of low activating martensitic 8?10% CrWVTa steels of type OPTIFER  

NASA Astrophysics Data System (ADS)

A series of low activating steels (OPTIFER-Ia, Ib, II, III and IV) has been developed as materials for the first wall and blanket structures of a future fusion device. The steels have been characterized by metallurgical examinations and by tests of the mechanical properties using tensile, impact bending and creep rupture tests. In comparison with conventional martensitic 9-12% CrMoVNb steels (e.g., MANET and P91 steels) a strong improvement of upper shelf impact energy and a remarkable shift to lower DBTT = -118C was obtained, whereas other mechanical data are similar. Fracture toughness can be optimized by proper selection of austenitization temperature, quenching and tempering treatment with a preference of a lower austenitizing temperature.

Schfer, L.; Schirra, M.; Ehrlich, K.

1996-10-01

107

A Novel Ni-Containing Powder Metallurgy Steel with Ultrahigh Impact, Fatigue, and Tensile Properties  

NASA Astrophysics Data System (ADS)

The impact toughness of powder metallurgy (PM) steel is typically inferior, and it is further impaired when the microstructure is strengthened. To formulate a versatile PM steel with superior impact, fatigue, and tensile properties, the influences of various microstructures, including ferrite, pearlite, bainite, and Ni-rich areas, were identified. The correlations between impact toughness with other mechanical properties were also studied. The results demonstrated that ferrite provides more resistance to impact loading than Ni-rich martensite, followed by bainite and pearlite. However, Ni-rich martensite presents the highest transverse rupture strength (TRS), fatigue strength, tensile strength, and hardness, followed by bainite, pearlite, and ferrite. With 74 pct Ni-rich martensite and 14 pct bainite, Fe-3Cr-0.5Mo-4Ni-0.5C steel achieves the optimal combination of impact energy (39 J), TRS (2170 MPa), bending fatigue strength at 2 106 cycles (770 MPa), tensile strength (1323 MPa), and apparent hardness (38 HRC). The impact energy of Fe-3Cr-0.5Mo-4Ni-0.5C steel is twice as high as those of the ordinary high-strength PM steels. These findings demonstrate that a high-strength PM steel with high-toughness can be produced by optimized alloy design and microstructure.

Wu, Ming-Wei; Shu, Guo-Jiun; Chang, Shih-Ying; Lin, Bing-Hao

2014-08-01

108

Springback evaluation for TRIP 800 steel sheets by simple bending tests  

NASA Astrophysics Data System (ADS)

TRIP steels, or Transformed Induced Plasticity steels, have excellent mechanical properties if compared with conventional steels. Strain hardening is also greater, thus they offer a good combination of strength and formability properties that may be justified by the multiphase structure of these steels. The highlighted characteristic of these steels is that they modify the microstructure with the deformation process as part of the austenite transforms to martensite, with the consequent change of the material properties. One of the main problems of TRIP steels is strong elastic recovery, or springback, after forming. In this work, the springback phenomenon is evaluated by bending tests and the influence of the variables involved in it is determined. The factor found to affect material recovery the most was the bending angle. Experimental bending forces do not agree with theoretical predictions.

Avellaneda, F. J.; Miguel, V.; Coello, J.; Martnez, A.; Calatayud, A.

2012-04-01

109

Influence of delta ferrite and dendritic carbides on the impact and tensile properties of a martensitic chromium steel  

Microsoft Academic Search

Martensitic chrome steels with a high content of chromium incline to form delta ferrite frequently accompanied by massive dendritic carbide precipitations. Both phases mostly influence the mechanical properties of this steel in countercurrent manner. The relatively soft delta ferrite causes an increase of ductility and toughness, whilst the brittle dendritic carbides decreases both. Both phases mostly decrease the strength of

L. Schfer

1998-01-01

110

Effect of delta ferrite on impact properties of low carbon 13Cr4Ni martensitic stainless steel  

Microsoft Academic Search

The effect of delta ferrite on impact properties of low carbon 13Cr4Ni martensitic stainless steel was studied by instrumented Charpy impact, SEM fractographic analysis and EDS. The experimental results indicated the presence of delta ferrite did not change the upper and lower shelf energy of the steel apparently, while lowered the impact energy remarkably in the transition temperature range and

P. Wang; S. P. Lu; N. M. Xiao; D. Z. Li; Y. Y. Li

2010-01-01

111

Effects of Manganese Content on Solidification Structures, Thermal Properties, and Phase Transformation Characteristics in Fe-Mn-C Steels  

NASA Astrophysics Data System (ADS)

The solidification structures and the thermal properties of Fe-Mn-C steel ingots containing different manganese contents have been investigated and the phase transformation characteristics have been revealed by Thermo-Calc to assist development of the continuous casting technology of Fe-Mn-C steels. The results show that the thermal conductivity of the 0Mn steel is higher than that of the 3Mn steel. The thermal conductivity of the 6Mn steel is the lowest in the three kinds of steels below 1023 K (750 C) and the highest above 1173 K (900 C). The 0Mn steel has the highest value of the proportion of equiaxed grain zone area in the three kinds of steels, whereas the 3Mn steel has the lowest value of it in the steels. Manganese has the effect of promoting the coarsening of grains. The microstructure is martensite and a little retained austenite (3.8 mass pct) in the 6Mn steel, whereas the microstructure is bainite in the 3Mn steel. The 0Mn steel is characterized by ferrite and pearlite. The mean thermal expansion coefficients of the steels are in the range from 1.0 10-5 to 1.6 10-5 K-1, and the determinations of mold tapers of the 6Mn and 3Mn steels can refer to low-carbon steel. Using RA <60 pct as the criterion, the third brittle temperature region of the 6Mn steel is 873 K to 1073 K (600 C to 800 C), whereas those of the 3Mn steel and the 0Mn steel are 873 K to 1123 K (600 C to 850 C) and 873 K to 1173 K (600 C to 900 C), respectively. In the 6Mn and 3Mn steels, the deformation-induced ferrite (DIF) forms in sufficient quantities cause the recovery of the ductility at the low temperature end. However, since low strains are present when straightening, sufficient quantities of DIF cannot be formed. Thus, the ductility of the 6Mn and 3Mn steels cannot be improved during the continuous casting process. Manganese has the effect of enlarging the austenite phase region and reducing the ?-ferrite phase region and ?-ferrite phase region.

Yang, Jian; Wang, Yu-Nan; Ruan, Xiao-Ming; Wang, Rui-Zhi; Zhu, Kai; Fan, Zheng-Jie; Wang, Ying-Chun; Li, Cheng-Bin; Jiang, Xiao-Fang

2015-02-01

112

High Strength Stainless Steel Properties that Affect Resistance Welding  

SciTech Connect

This report discusses results of a study on selected high strength stainless steel alloy properties that affect resistance welding. The austenitic alloys A-286, JBK-75 (Modified A-286), 21-6-9, 22-13-5, 316 and 304L were investigated and compared. The former two are age hardenable, and the latter four obtain their strength through work hardening. Properties investigated include corrosion and its relationship to chemical cleaning, the effects of heat treatment on strength and surface condition, and the effect of mechanical properties on strength and weldability.

Kanne, W.R.

2001-08-01

113

Simulation of the Mechanical Performance of Cast Steel with Porosity: Static Properties  

E-print Network

Simulation of the Mechanical Performance of Cast Steel with Porosity: Static Properties R.A. Hardin As designers look to lighter-weight, thinner-walled steel castings, knowledge of the location, amount.A., and Beckermann, C., "Simulation of the Mechanical Performance of Cast Steel with Porosity: Static Properties

Beckermann, Christoph

114

Corrosion and mechanical properties of duplex-treated 301 stainless steel  

Microsoft Academic Search

Plasma nitriding is a widely used technique for increasing the surface hardness of stainless steels, and consequently, for improving their tribological properties. It is also used to create an interface between soft stainless steel substrates and hard coatings to improve adhesion. This paper reports on the mechanical and corrosion properties of AISI301 stainless steel (SS) after a duplex treatment consisting

M. Azzi; M. Benkahoul; J. E. Klemberg-Sapieha; L. Martinu

2010-01-01

115

Evaluation of Microstructure and Mechanical Properties in Dissimilar Austenitic/Super Duplex Stainless Steel Joint  

NASA Astrophysics Data System (ADS)

To study the effect of chemical composition on microstructural features and mechanical properties of dissimilar joints between super duplex and austenitic stainless steels, welding was attempted by gas tungsten arc welding process with a super duplex (ER2594) and an austenitic (ER309LMo) stainless steel filler metal. While the austenitic weld metal had vermicular delta ferrite within austenitic matrix, super duplex stainless steel was mainly comprised of allotriomorphic grain boundary and Widmansttten side plate austenite morphologies in the ferrite matrix. Also the heat-affected zone of austenitic base metal comprised of large austenite grains with little amounts of ferrite, whereas a coarse-grained ferritic region was observed in the heat-affected zone of super duplex base metal. Although both welded joints showed acceptable mechanical properties, the hardness and impact strength of the weld metal produced using super duplex filler metal were found to be better than that obtained by austenitic filler metal.

Rahmani, Mehdi; Eghlimi, Abbas; Shamanian, Morteza

2014-10-01

116

Ultrasonic investigations of cermets elastic properties in dependence on steel concentration and temperature of sintering  

NASA Astrophysics Data System (ADS)

Cermets is a ceramic-metal composite usually produced by sintering a precompacted mixture of the initial powders. These composite materials were created for industrial applications to produce engineering structures possessing a high strength, thermal stability and resistance to aggressive media. In the present work elastic properties of cermets samples, obtained by sintering of corundum (?-Al2O3) and stainless steel powders were investigated in dependence on steel concentration 5 - 35% wt. and on temperature of sintering in vacuum 1400-1700C. It was stated that values of elastic moduli are in complex dependence on concentration and temperature, reach maxima at steel concentration 15 - 20% wt. and increase with sintering temperature rise. In the work also the results of cermets microstructure researches and discussion of these results are presented. The results are discussed from stand view of ultrasound propagation through medium having grain boundaries which influence on the physical properties of composite.

Abramovich, A.

2012-12-01

117

Fatigue Properties of Steel Cord-Rubber Composite  

Microsoft Academic Search

The fatigue properties of [20] steel cord-rubber laminated composite under tension-tension (T-T) loading are studied in this paper. The results show that the variation of the cycle strain in the fatigue process under the constant cycle loading exhibits three stages which correspond to damage initiation, steady damage propagation and catastrophic failure. Two-step experiments demonstrate that the strain variation in step-2

Zhenhui Tian; Hongwei Song; Zhimin Wan; Xingwen Du

2001-01-01

118

Magnetic properties of maraging steels in relation to nickel concentration  

SciTech Connect

Magnetic properties of maraging steels have been investigated as a function of nickel concentration. The alloys nickel content varied from 12 to 24 wt pct, while other alloying constituents were kept at a level maintained in the 18Ni-2,400 MPA-grade maraging steel. The magnetic properties were determined following aging for 1 hour in the temperature range of 450 to 750 C. In every alloy investigated, the coercive field increased with aging temperature, reaching a maximum around 670 C {+-} 30 C. The saturation magnetization values were lowest around temperatures where maximum coercive field was observed. The coercive field increased from {approximately}55 to {approximately}175 Oe ({approximately}4,380 to {approximately} 13,900 amp/meter) and the corresponding saturation magnetization decreased from {approximately}18,500 to {approximately}4,000 G ({approximately}1.85 to {approximately}0.4 T) in the alloys containing 12 and 24 wt pct Ni, respectively. The reverted austenite increased from 25 vol pct at 12 wt pct Ni to 10 vol pct at 24 wt pct Ni. The hardness and Charpy impact strength of the alloys have also been determined. An attempt has been made to correlate magnetic properties with different phase transformations occurring in maraging steels.

Ahmed, M.; Nasim, I.; Ayub, H. [Dr. A.Q. Khan Research Labs., Rawalpindi (Pakistan); Hasnain, K. [Quaid-i-Azam Univ., Islamabad (Pakistan)

1995-07-01

119

Stabilization of small deformations of maraging steels by stress relaxation  

SciTech Connect

The possibility of increasing the forming accuracy with small degrees of deformation of maraging steel by aging of it under stress after deformation was investigated. Aging under stress of water hardened VNS-2 maraging steel was done in the elastic area and after deformation to epsilon = 6% at 450/degree/: No. 12, (Dec 1987)C, a temperature corresponding to the maximum degree of dispersion hardening. The influence of the degree of deformation on the mechanical properties of the steel, the residual deformation, and stabilization of the ratio of the residual to the total deformations were determined. The structural condition of the martensite and the degree of solid solution decomposition were studied by x-ray diffraction analysis. The proposed treatment led to complete stabilization of the specified deformations with simultaneous strengthening and made it possible to obtain high accuracy in production of small curvature parts.

Alekseeva, L.E.; Koritskaya, G.I.; Talalakina, E.I.

1988-05-01

120

Mechanical and tribological properties of AISI 304 stainless steel nitrided by glow discharge compared to ion implantation and plasma immersion ion implantation  

NASA Astrophysics Data System (ADS)

Results about mechanical and tribological behavior of AISI 304 stainless steel nitrided by three different ion beam processes - glow discharge (GD), ion implantation (II) and plasma immersion ion implantation (PI3) are reported. Expanded austenite ? N and nitrides phases (Fe 2+ xN, ?'-Fe 4N and Cr-N) were identified as a function of nitriding conditions. Hardness (H) and elastic modulus (E) profiles were obtained by instrumented penetration. The hardness reached values as high as 21 GPa by PI3. Tribological behavior was studied by reciprocating sliding tests with a WC (Co) ball at room temperature (RT) in dry condition. Different wear regimes were identified in the friction coefficient profiles. The profile form and the running-in distance are strongly dependent on the nitriding process. Adhesive and abrasive wear components can be inferred from these friction profiles. Hardness and tribological performance, after the nitriding processes, are discussed in terms of surface microstructure.

Foerster, C. E.; Serbena, F. C.; da Silva, S. L. R.; Lepienski, C. M.; Siqueira, C. J. de M.; Ueda, M.

2007-04-01

121

Electric arc deposition of carbon steel coatings with improved mechanical properties  

NASA Astrophysics Data System (ADS)

To achieve high deposition rate and efficiency, electric arc spraying has been routinely used to deposit carbon steel coatings. Although retention of carbon in these coatings is poor due to the use of compressed air during spraying, the coatings are sufficiently hardened by brittle iron oxide inclusions to be suitable for hardfacing mechanical components used in mild adhesive and abrasive wear environments. However, carbon steel coatings can be employed for hardfacing mechanical components used in more aggressive wear environments, provided they are hardened by the carbon retention rather than by iron oxide inclu-sions. Therefore, to increase retention of carbon, reduce inclusion of iron oxides, and improve hardness and wear properties of carbon steel coatings, deposition experiments were carried out using an inexpen-sive nitrogen, which is produced on-site by a pressure swing adsorption or a membrane separation sys-tem, instead of compressed air during spraying.

Zurecki, Z.; Garg, D.; Bowe, D.

1997-12-01

122

Influence of banded structure on the mechanical properties of a high-strength maraging steel  

SciTech Connect

Chemical inhomogeneity results in the formation of banded structure in high-strength maraging steels. Segregation of titanium and molybdenum was found to be the primary cause of banded structure formation. When the concentrations of these elements increased beyond certain critical levels, bands comprising different grain sizes formed. The inclusions existed preferentially along the interface of the bands. A high-temperature homogenization treatment substantially reduced or eliminated the banded structure. The large grain size resulting from the homogenization treatment was subsequently reduced by a grain refinement treatment. The mechanical properties of the steel substantially improved following homogenization and grain refinement.

Ahmed, M.; Salam, I.; Hashmi, F.H.; Khan, A.Q. [Dr. A.Q. Khan Research Labs., Rawalpindi (Pakistan). Metallurgy Div.

1997-04-01

123

Microstructural Developments and Tensile Properties of Lean Fe-Mn-Al-C Lightweight Steels  

NASA Astrophysics Data System (ADS)

Concepts of Fe-Al-Mn-C-based lightweight steels are fairly simple, but primary metallurgical issues are complicated. In this study, recent studies on lean-composition lightweight steels were reviewed, summarized, and emphasized by their microstructural development and mechanical properties. The lightweight steels containing a low-density element of Al were designed by thermodynamic calculation and were manufactured by conventional industrial processes. Their microstructures consisted of various secondary phases as ?-carbide, martensite, and austenite in the ferrite matrix according to manufacturing and annealing procedures. The solidification microstructure containing segregations of C, Mn, and Al produced a banded structure during the hot rolling. The (ferrite + austenite) duplex microstructure was formed after the annealing, and the austenite was retained at room temperature. It was because the thermal stability of austenite nucleated from fine ?-carbide was quite high due to fine grain size of austenite. Because these lightweight steels have outstanding properties of strength and ductility as well as reduced density, they give a promise for automotive applications requiring excellent properties.

Sohn, S. S.; Lee, S.; Lee, B.-J.; Kwak, J.-H.

2014-09-01

124

Effect of manganese and niobium on the properties of low-alloy steels  

Microsoft Academic Search

The strength and ductility characteristics, toughness parameters, and structure of low-alloy steels after thermomechanical\\u000a treatment are studied. Analysis of the properties of steels with various manganese-to-niobium ratios is performed. An optimum\\u000a chemical composition for sheet steel subjected to thermomechanical treatment is suggested.

S. V. Aleksandrov; K. Hulka; A. M. Stepashin; Yu. D. Morozov

2005-01-01

125

Influence of C, Mn and Ni Contents on Microstructure and Properties of Strong Steel  

E-print Network

Influence of C, Mn and Ni Contents on Microstructure and Properties of Strong Steel Weld Metals. % were investigated in high strength steel weld metals with 2 wt. % manganese. It was found that nickel. Introduction High strength steel with yield strength greater than 690 MPa (100 ksi) has been welded

Cambridge, University of

126

A SURVEY OF THE STRUCTURAL PROPERTIES OF SOME HIGH STRENGTH SHEET STEELS  

Microsoft Academic Search

Presented at the Fifth Meeting of the Structures and Materials Panel, ; Apr. 24 to 27, 1957, in Oslo, Norway. This paper deals primarily with the ; structural properties of the sheet steels; however, a brief strength-weight ; evaluation of steel, titanium, and aluminum is made for purposes of orientation. ; The heat-treatable stainless steels which are specifically covered are

Melcon

1957-01-01

127

Deformation behavior of high speed steel/low Carbon steel composite with harmonic structure by MM/SPS process  

NASA Astrophysics Data System (ADS)

The harmonic-structured composite that consists of a network fine grain region with a high speed steel and a dispersed coarse grain region with a low carbon steel was fabricated prepared using a mechanical milling, which is one of the severe plastic deformation method, and spark plasma sintering process. The microstructure and mechanical properties harmonic- structured composite compact were evaluated by a scaning electron microscope and a tensile test, respectively. The harmonic-structured composite exhibited high strength and enough ductility compared with a conventional particle-dispersed composite with the same weight ratio of high speed steel/low carbon steel. The microstructure observation of harmonic-structured composite revieals that the superior elongation of the harmonic-structured composite is attributed to the plastic deformation around the cracks which initiate at the network area.

Tsuzuki, Y.; Fujiwara, H.; Miyamoto, H.; Ameyama, K.

2014-08-01

128

Correlation of Mechanical Properties with Fracture Surface Features in a Newly Developed Dual-Phase Steel  

NASA Astrophysics Data System (ADS)

Dual-phase (DP) steels were produced by a newly developed method utilizing simple cold-rolling and subsequent short intercritical annealing of a martensite-ferrite duplex starting structure. Tensile testing revealed an excellent strength-elongation balance (UTS UE ? 110-150 J/cm3) for the DP steels in comparison with the commercially used high strength steels. Fracture surfaces of the tensile specimens were studied by scanning electron microscopy analysis and image processing. Mechanical properties were correlated with fracture surface features. It was found that the variation of the total elongation and strength-elongation balance with the martensite volume fraction could be well correlated with the variation of the average dimple area. The variation of the yield strength and dimple areal density with the martensite volume fraction followed the same trend.

Mazaheri, Y.; Saeidi, N.; Kermanpur, A.; Najafizadeh, A.

2015-04-01

129

Correlation of Mechanical Properties with Fracture Surface Features in a Newly Developed Dual-Phase Steel  

NASA Astrophysics Data System (ADS)

Dual-phase (DP) steels were produced by a newly developed method utilizing simple cold-rolling and subsequent short intercritical annealing of a martensite-ferrite duplex starting structure. Tensile testing revealed an excellent strength-elongation balance (UTS UE ? 110-150 J/cm3) for the DP steels in comparison with the commercially used high strength steels. Fracture surfaces of the tensile specimens were studied by scanning electron microscopy analysis and image processing. Mechanical properties were correlated with fracture surface features. It was found that the variation of the total elongation and strength-elongation balance with the martensite volume fraction could be well correlated with the variation of the average dimple area. The variation of the yield strength and dimple areal density with the martensite volume fraction followed the same trend.

Mazaheri, Y.; Saeidi, N.; Kermanpur, A.; Najafizadeh, A.

2015-02-01

130

Fracture properties evaluation of stainless steel piping for LBB applications  

SciTech Connect

The objective of this paper is to evaluate the material properties of SA312 TP316 and SA312 TP304 stainless steels and their associated welds manufactured for shutdown cooling line and safety injection line of nuclear generating stations. A total of 82 tensile tests and 58 fracture toughness tests on specimens taken from actual pipes were performed and the effect of various parameters such as the pipe size, the specimen orientation, the test temperature and the welding procedure on the material properties are discussed. Test results show that the effect of the test temperature on the fracture toughness was significant while the effects of the pipe size and the specimen orientation on the fracture toughness were negligible. The material properties of the GTAW weld metal was in general higher than those of the base metal.

Kim, Y.J.; Seok, C.S.; Chang, Y.S. [Sung Kyun Kwan Univ., Suwon (Korea, Republic of)

1997-04-01

131

The dependence of magnetic properties on fatigue in A533B nuclear pressure vessel steels  

SciTech Connect

Cyclic loading causes cumulative microstructural changes in materials. The magnetic properties of A533B steel are determined by both initial microstructures and microstructural changes induced by fatigue damage. From the results of a series of strain-controlled fatigue tests, the magnetic properties were found to change systematically with fatigue damage throughout the fatigue life. A linear relationship between magnetic remanence and mechanical modulus was observed. The fatigue lifetimes were also dependent on the initial microstructure, and a relationship between these lifetimes and pre-fatigue magnetic properties such as coercivity was observed. Therefore this study has demonstrated that magnetic measurements can be exploited to evaluate the progress of fatigue damage in steel.

Bi, Y.; Govindaraju, M.R.; Jiles, D.C. [Iowa State Univ., Ames, IA (United States). Center for NDE] [Iowa State Univ., Ames, IA (United States). Center for NDE

1997-09-01

132

Effect of welding process on the microstructure and properties of dissimilar weld joints between low alloy steel and duplex stainless steel  

NASA Astrophysics Data System (ADS)

To obtain high-quality dissimilar weld joints, the processes of metal inert gas (MIG) welding and tungsten inert gas (TIG) welding for duplex stainless steel (DSS) and low alloy steel were compared in this paper. The microstructure and corrosion morphology of dissimilar weld joints were observed by scanning electron microscopy (SEM); the chemical compositions in different zones were detected by energy-dispersive spectroscopy (EDS); the mechanical properties were measured by microhardness test, tensile test, and impact test; the corrosion behavior was evaluated by polarization curves. Obvious concentration gradients of Ni and Cr exist between the fusion boundary and the type II boundary, where the hardness is much higher. The impact toughness of weld metal by MIG welding is higher than that by TIG welding. The corrosion current density of TIG weld metal is higher than that of MIG weld metal in a 3.5wt% NaCl solution. Galvanic corrosion happens between low alloy steel and weld metal, revealing the weakness of low alloy steel in industrial service. The quality of joints produced by MIG welding is better than that by TIG welding in mechanical performance and corrosion resistance. MIG welding with the filler metal ER2009 is the suitable welding process for dissimilar metals jointing between UNS S31803 duplex stainless steel and low alloy steel in practical application.

Wang, Jing; Lu, Min-xu; Zhang, Lei; Chang, Wei; Xu, Li-ning; Hu, Li-hua

2012-06-01

133

Microstructures and Mechanical Properties of High-Mn TRIP Steel Based on Warm Deformation of Martensite  

NASA Astrophysics Data System (ADS)

High-Mn TRIP steel with about 5 wt pct Mn was prepared by a thermo-mechanical treatment based on warm deformation of martensite and subsequent short-time annealing in the intercritical region. The microstructural evolution and the mechanical properties of the used steel during such treatment were investigated. The results indicate that during warm deformation of martensite in the intercritical region, the decomposition of martensite was accelerated by warm deformation and the occurrence of dynamic recrystallization of ferrite led to the formation of equiaxed ferrite grains. Meanwhile, the reverse transformation of austenite was accelerated by warm deformation to some extent. During subsequent annealing in the intercritical region, static recrystallization of ferrite led to the increase in the fraction of equiaxed ferrite grains, and the formation of the reversed austenite was accelerated by the addition of the deformation-stored energy, while the stability of the reversed austenite was improved by the accelerated diffusions of C atoms and Mn atoms. As a whole, the mechanical properties of the used steel by the thermo-mechanical treatment based on warm deformation of martensite and subsequent short-time annealing in the intercritical region were comparable to the steels with similar compositions subjected to intercritical annealing for hours after cold rolling of martensite.

Guo, Zhikai; Li, Longfei; Yang, Wangyue; Sun, Zuqing

2015-01-01

134

Microstructures and Mechanical Properties of High-Mn TRIP Steel Based on Warm Deformation of Martensite  

NASA Astrophysics Data System (ADS)

High-Mn TRIP steel with about 5 wt pct Mn was prepared by a thermo-mechanical treatment based on warm deformation of martensite and subsequent short-time annealing in the intercritical region. The microstructural evolution and the mechanical properties of the used steel during such treatment were investigated. The results indicate that during warm deformation of martensite in the intercritical region, the decomposition of martensite was accelerated by warm deformation and the occurrence of dynamic recrystallization of ferrite led to the formation of equiaxed ferrite grains. Meanwhile, the reverse transformation of austenite was accelerated by warm deformation to some extent. During subsequent annealing in the intercritical region, static recrystallization of ferrite led to the increase in the fraction of equiaxed ferrite grains, and the formation of the reversed austenite was accelerated by the addition of the deformation-stored energy, while the stability of the reversed austenite was improved by the accelerated diffusions of C atoms and Mn atoms. As a whole, the mechanical properties of the used steel by the thermo-mechanical treatment based on warm deformation of martensite and subsequent short-time annealing in the intercritical region were comparable to the steels with similar compositions subjected to intercritical annealing for hours after cold rolling of martensite.

Guo, Zhikai; Li, Longfei; Yang, Wangyue; Sun, Zuqing

2015-04-01

135

Characterization of Properties in Friction Welded Stainless Steel and Copper Materials  

NASA Astrophysics Data System (ADS)

The aim of this study is to investigate the metallurgical and mechanical properties of friction welded stainless steel-copper joints. One of the manufacturing methods used to produce parts made from different materials is the friction welding method. Application of classical welding techniques to such materials is difficult because of they have different thermal properties. Stainless steel-copper joints are inevitable for certain applications due to unique performances such as higher electric conductivity, heat conductivity, corrosion resistance, and mechanical properties. In the present study, austenitic stainless steel and copper parts were joined by friction welding. Tensile, fatigue, and notch-impact tests were applied to friction welded specimens, and the results were compared with those for the original materials. Microstructure, energy dispersive x-ray, and x-ray diffraction (XRD) analysis and hardness variations were conducted on the joints. Results showed that various intermetallic phases such as FeCu4 and Cu2NiZn occurred at the interface. It was found from the microstructure and XRD analysis that intermetallic phases formed in the interface which further caused a decrease in the strength of the joints. However, hardness of the copper increased slightly, whereas the hardness of steel decreases slightly on the horizontal distance from the center.

Sahin, Mumin; ?l, Ender; Misirli, Cenk

2013-03-01

136

Mechanical properties and fracture toughness of rail steels and thermite welds at low temperature  

NASA Astrophysics Data System (ADS)

Brittle fracture occurs frequently in rails and thermite welded joints, which intimidates the security and reliability of railway service. Railways in cold regions, such as Qinghai-Tibet Railway, make the problem of brittle fracture in rails even worse. A series of tests such as uniaxial tensile tests, Charpy impact tests, and three-point bending tests were carried out at low temperature to investigate the mechanical properties and fracture toughness of U71Mn and U75V rail steels and their thermite welds. Fracture micromechanisms were analyzed by scanning electron microscopy (SEM) on the fracture surfaces of the tested specimens. The ductility indices (percentage elongation after fracture and percentage reduction of area) and the toughness indices (Charpy impact energy A k and plane-strain fracture toughness K IC) of the two kinds of rail steels and the corresponding thermite welds all decrease as the temperature decreases. The thermite welds are more critical to fracture than the rail steel base metals, as indicated by a higher yield-to-ultimate ratio and a much lower Charpy impact energy. U71Mn rail steel is relatively higher in toughness than U75V, as demonstrated by larger A k and K IC values. Therefore, U71Mn rail steel and the corresponding thermite weld are recommended in railway construction and maintenance in cold regions.

Wang, Yuan-qing; Zhou, Hui; Shi, Yong-jiu; Feng, Bao-rui

2012-05-01

137

Effect of microstructure on static and dynamic mechanical properties of high strength steels  

NASA Astrophysics Data System (ADS)

The high speed deformation behavior of a commercially available dual phase (DP) steel was studied by means of split Hopkinson bar apparatus in shear punch (25m/s) and tension (1000s-1) modes with an emphasis on the influence of microstructure. The cold rolled sheet material was subjected to a variety of heat treatment conditions to produce several different microstructures, namely ferrite plus pearlite, ferrite plus bainite and/or acicular ferrite, ferrite plus bainite and martensite, and ferrite plus different fractions of martensite. Static properties (0.01mm/s for shear punch and 0.001s -1 for tension) of all the microstructures were also measured by an MTS hydraulic machine and compared to the dynamic properties. The effects of low temperature tempering and bake hardening were investigated for some ferrite plus martensite microstructures. In addition, two other materials, composition designed as high strength low alloy (HSLA) steel and transformation induced plasticity (TRIP) steel, were heat treated and tested to study the effect of alloy chemistry on the microstructure and property relationship. A strong effect of microstructure on both static and dynamic properties and on the relationship between static and dynamic properties was observed. According to the variation of dynamic factor with static strength, three groups of microstructures with three distinct behaviors were identified, i.e. classic dual phase (ferrite plus less than 50% martensite), martensite-matrix dual phase (ferrite plus more than 50% martensite), and non-dual phase (ferrite plus non-martensite). Under the same static strength level, the dual phase microstructure was found to absorb more dynamic energy than other microstructures. It was also observed that the general dependence of microstructure on static and dynamic property relationship was not strongly influenced by chemical composition, except the ferrite plus martensite microstructures generated by the TRIP chemistry, which exhibited much better dynamic factor values. This may suggest that solid solution strengthening should be more utilized in the design of crashworthy dual phase steels.

Qu, Jinbo

138

Impurity release and deuterium retention properties of a ferritic steel wall in JFT-2M  

NASA Astrophysics Data System (ADS)

Impurity release and the deuterium retention properties of the low activation ferritic steel, which is a candidate material for a demo-reactor, have been studied in the JFT-2M and in the laboratory. In the case when the inside vacuum vessel wall is fully covered by ferritic steel plates, enhancement of the oxygen influx and the emission of iron ion lines were not observed. This means that the impurity release from the ferritic steel has no deleterious effect on JFT-2M. From irradiation experiments, the retained amount of deuterium in the sample with an oxide layer was one order of magnitude larger than that of the mechanically polished sample for the low fluence case. However it became comparable at the high fluence case, and was roughly the same as that of SUS-316L. Retained amount of deuterium in the sample exposed to JFT-2M plasmas was similar to that exposed to the deuterium ion beam.

Ogawa, H.; Yamauchi, Y.; Tsuzuki, K.; Kawashima, H.; Sato, M.; Shinohara, K.; Kamiya, K.; Kasai, S.; Kusama, Y.; Yamaguchi, K.; Hirohata, Y.; Hashiba, M.; Hino, T.

2004-08-01

139

Effect of microstructure on low cycle fatigue properties of ODS steels  

NASA Astrophysics Data System (ADS)

Low cycle fatigue properties at room temperature, 650 C and 750 C of three high chromium steels (9%Cr ferritic-martensitic and two 14%Cr ferritic steels) strengthened by oxide dispersion were studied and compared. Cyclic softening/hardening curves, cyclic deformation curves, S-N curves and Coffin-Manson curves are presented together with microstructural observations. Differences in cyclic response, stress level and fatigue life are attributed to differences in the matrix microstructure. The oxide particles stabilize the cyclic response, even if cyclic softening is detected for some experimental conditions. The strength of these steels is discussed in terms of strengthening mechanisms such as grain size effect, particle-dislocations interaction and dislocation density. Comparing three different ODS steels offers an opportunity to tests the contribution of individual mechanisms to the cyclic strength. The reduction of fatigue life in one of the ferritic steels is explained by the presence of large grains, facilitating the fatigue crack nucleation and the early growth.

Kubena, Ivo; Fournier, Benjamin; Kruml, Tomas

2012-05-01

140

Correlations between Nanoindentation Hardness and Macroscopic Mechanical Properties in DP980 Steels  

SciTech Connect

Multiphase advanced high strength steels (AHSS) are being increasingly used in the automotive industry due to their low cost, good availability and excellent combination of strength and ductility. There is a keen interest from the automotive and steel industry for more fundamental understandings on the key microstructure features influencing the macroscopic properties, i.e., tensile properties, hole-expansion ratio and localized formability of AHSS. In this study, the micro- and macro-level properties for eight commercial DP980 steels are first characterized and quantified with various experimental methods. Correlations between macroscopic-level properties and relationships between various micro- and macro- properties for these steels are then established based on the experimental measurements. It is found that, despite their differences in their chemistry, processing parameters and sheet thickness, the eight DP980 steels do have common microstructural level properties governing their specific macroscopic properties in terms of strength, elongation and hole expansion performance.

Taylor, Mark D.; Choi, Kyoo Sil; Sun, Xin; Matlock, David K.; Packard, Corrine; Xu, Le; Barlat, Frederic

2014-03-01

141

Improved mechanical properties of A 508 class 3 steel for nuclear pressure vessel through steelmaking  

SciTech Connect

The present work is concerned with the steelmaking practices which improve the mechanical properties of the A 508 class 3 steel for reactor pressure vessel. Three kinds of steelmaking practices were applied to manufacture the forged heavy wall shell for reactor pressure vessel, that is, the vacuum carbon deoxidation (VCD), modified VCD containing aluminum and silicon-killing. The segregation of the chemical elements through the thickness was quite small so that the variations of the tensile properties at room temperature were small and the anisotropy of the impact properties was hardly observed regardless of the steelmaking practices. The Charpy V-notch impact properties and the reference nil-ductile transition temperature by drop weight test were significantly improved by the modified VCD and silicon-killing as compared with those of the steel by VCD. Moreover, the plane strain fracture toughness values of the materials by modified VCD and silicon-killing practices was much higher than those of the steel by VCD. These were resulted from the fining of austenite grain size. It was observed that the grain size was below 20 {micro}m (ASTM No. 8.5) when using the modified VCD and silicon-killing, compared to 50 {micro}m (ASTM No. 7.0) when using VCD.

Kim, J.T.; Kwon, H.K.; Kim, K.C.; Kim, J.M. [Korea Heavy Industries and Construction Co., Ltd., Changwon (Korea, Republic of)

1997-12-31

142

Effect of prior cold work on creep properties of a titanium modified austenitic stainless steel  

NASA Astrophysics Data System (ADS)

Prior cold worked (PCW) titanium-modified 14Cr-15Ni austenitic stainless steel (SS) is used as a core-structural material in fast breeder reactor because of its superior creep strength and resistance to void swelling. In this study, the influence of PCW in the range of 16-24% on creep properties of IFAC-1 SS, a titanium modified 14Cr-15Ni austenitic SS, at 923 K and 973 K has been investigated. It was found that PCW has no appreciable effect on the creep deformation rate of the steel at both the test temperatures; creep rupture life increased with PCW at 923 K and remained rather unaffected at 973 K. The dislocation structure along with precipitation in the PCW steel was found to change appreciably depending on creep testing conditions. A well-defined dislocation substructure was observed on creep testing at 923 K; a well-annealed microstructure with evidences of recrystallization was observed on creep testing at 973 K. Creep rupture life of the steel increased with the increase in PCW at 923 K. This has been attributed to the partial retention of prior cold work induced dislocations which facilitated the extensive precipitation of secondary Ti(C,N) particles on the stable dislocation substructure. Creep rupture life of the steel did not vary with PCW at 973 K due to softening by recrystallization and absence of secondary Ti(C,N).

Vijayanand, V. D.; Parameswaran, P.; Nandagopal, M.; Panneer Selvi, S.; Laha, K.; Mathew, M. D.

2013-07-01

143

Superior Charpy impact properties of ODS ferritic steel irradiated in JOYO  

NASA Astrophysics Data System (ADS)

The effect of neutron irradiation on Charpy impact properties of an ODS ferritic steel developed by PNC was studied. The miniaturized Charpy V-notch (MCVN) specimens (1.5 1.5 20 mm) of two orientations (longitudinal, called 1DS-L, and transverse, 1DS-T) were irradiated to fluence levels of (0.3-3.8) 10 26 n/m 2 ( E n > 0.1 MeV) between 646 and 845 K in JOYO. MCVN specimens before and after the irradiation were subjected to instrumented Charpy impact tests. The test results and fracture surface observations showed that in the unirradiated state the steel showed no ductile-to-brittle transition behavior until 153 K regardless of orientation and the upper shelf energy of the steel was as high as that of a high-strength ferritic steel without dispersed oxide. Such excellent impact properties were essentially maintained after the irradiation although an appreciable decrease in absorbed energy occurred by higher temperature irradiations at and above 793 K.

Kuwabara, T.; Kurishita, H.; Ukai, S.; Narui, M.; Mizuta, S.; Yamazaki, M.; Kayano, H.

1998-10-01

144

Effect of rust on the wettability of steel by water  

SciTech Connect

Rust, as formed on steel by immersion of low-carbon steel in water, was found to improve the wettability of steel by water. The advancing contact angle decreased from 87{degree} to 32{degree}, and the receding contact angle decreased from 81{degree} to 29{degree}. Cleansing of steel by acetone also helped improve the wettability, but the advancing angle only decreased from 87{degree} to 73{degree}, and the receding angle only decreased from 81{degree} to 41{degree}.

Lu, W.; Chung, D.D.L. [State Univ. of New York, Buffalo, NY (United States). Composite Materials Research Lab.] [State Univ. of New York, Buffalo, NY (United States). Composite Materials Research Lab.

1998-04-01

145

Effect of Carbon Content on Mechanical Properties and Weather Resistance of High Performance Bridge Steels  

Microsoft Academic Search

The influence of carbon content on the mechanical properties of high yield strength bridge steel has been investigated. The results show that the excellent mechanical properties and corrosion resistance are obtained for the steel with carbon content of 0.03% 0.05% (mass percent). According to the results, a new weathering bridge steel plate with carbon content of 0.045% (mass percent)

Jia GUO; Cheng-jia SHANG; Shan-wu YANG; Ying WANG; Lian-wei WANG; Xin-lai HE

2009-01-01

146

The effects of hydrogen on the fracture toughness properties of upset welded stainless steel  

Microsoft Academic Search

The effects of hydrogen on the fracture toughness properties of upset welded Type 304L stainless steel were measured and compared to those measured previously for as-received and as-welded steels. The results showed that the upset welded steels had good fracture toughness properties, but values were lower than the as-received material. The fracture toughness value of the base material was 6420

1995-01-01

147

Characterization of thermal aging of duplex stainless steel by SQUID  

SciTech Connect

Thermal aging is a growing concern for long-term-aged duplex stainless steel piping in nuclear power plants. Superconducting QUantum Interference Device (SQUID) was used for the detection of thermal aging of SUS329 rolled duplex stainless steel and SCS16 cast duplex stainless steel. It was found that the SQUID output signal pattern in the presence of AC magnetic field applied to the specimen was sensitive to the changes in electromagnetic properties due to thermal aging.

Isobe, Y.; Kamimura, A.; Aoki, K.; Nakayasu, F. [Nuclear Fuel Industries, Ltd., Osaka (Japan)

1995-08-01

148

Report on thermal aging effects on tensile properties of ferritic-martensitic steels.  

SciTech Connect

This report provides an update on the evaluation of thermal-aging induced degradation of tensile properties of advanced ferritic-martensitic steels. The report is the first deliverable (level 3) in FY11 (M3A11AN04030103), under the Work Package A-11AN040301, 'Advanced Alloy Testing' performed by Argonne National Laboratory, as part of Advanced Structural Materials Program for the Advanced Reactor Concepts. This work package supports the advanced structural materials development by providing tensile data on aged alloys and a mechanistic model, validated by experiments, with a predictive capability on long-term performance. The scope of work is to evaluate the effect of thermal aging on the tensile properties of advanced alloys such as ferritic-martensitic steels, mod.9Cr-1Mo, NF616, and advanced austenitic stainless steel, HT-UPS. The aging experiments have been conducted over a temperature of 550-750 C for various time periods to simulate the microstructural changes in the alloys as a function of time at temperature. In addition, a mechanistic model based on thermodynamics and kinetics has been used to address the changes in microstructure of the alloys as a function of time and temperature, which is developed in the companion work package at ANL. The focus of this project is advanced alloy testing and understanding the effects of long-term thermal aging on the tensile properties. Advanced materials examined in this project include ferritic-martensitic steels mod.9Cr-1Mo and NF616, and austenitic steel, HT-UPS. The report summarizes the tensile testing results of thermally-aged mod.9Cr-1Mo, NF616 H1 and NF616 H2 ferritic-martensitic steels. NF616 H1 and NF616 H2 experienced different thermal-mechanical treatments before thermal aging experiments. NF616 H1 was normalized and tempered, and NF616 H2 was normalized and tempered and cold-rolled. By examining these two heats, we evaluated the effects of thermal-mechanical treatments on material microstructures and associated mechanical properties during long-term aging at elevated temperatures. Thermal aging experiments at different temperatures and periods of time have been completed: 550 C for up to 5000 h, 600 C for up to 7500 h, and 650 C for more than 10,000 h. Tensile properties were measured on thermally aged specimens and aging effect on tensile behavior was assessed. Effects of thermal aging on deformation and failure mechanisms were investigated by using in-situ straining technique with simultaneous synchrotron XRD measurements.

Li, M.; Soppet, W.K.; Rink, D.L.; Listwan, J.T.; Natesan, K. (Nuclear Engineering Division)

2012-05-10

149

Structure and properties of plasma-nitrided stainless steel  

Microsoft Academic Search

A series of plasma-nitriding experiments has been conducted on AISI 304L austenitic stainless steel at temperatures ranging from 400 to 600 C using a pulsed d.c. plasma with various pulse duration\\/repetition ratios in an N2?H2 gas mixture. The structure and composition of the plasma-nitrided surface layer were analysed by means of X-ray diffraction (XRD), scanning electron microscopy, X-ray photoelectron spectroscopy

E. Menthe; K.-T. Rie; J. W. Schultze; S. Simson

1995-01-01

150

Microstructure and mechanical properties of Selective Laser Melted 18Ni-300 steel  

NASA Astrophysics Data System (ADS)

Selective Laser Melting (SLM) is an Additive Manufacturing process in which a part is built in a layer by layer manner. A laser source selectively scans the powder bed according to the CAD data of the part to be produced. The high intensity laser beam makes it possible to completely melt the metal powder particles to obtain almost fully dense parts. In this work, the influence of process parameters in SLM (e.g. scan speed and layer thickness) and various age hardening treatments on the microstructure and mechanical properties of 18Ni-300 steel is investigated. It is shown that almost fully dense parts with mechanical properties comparable to those of conventionally produced maraging steel 300 can be produced by SLM.

Kempen, K.; Yasa, E.; Thijs, L.; Kruth, J.-P.; Van Humbeeck, J.

151

Correlating microstructural features and mechanical properties with abrasion resistance of a high strength low alloy steel  

Microsoft Academic Search

A study towards the examination of the abrasive wear behaviour and other characteristics, viz. microstructure, tensile properties and hardness of a high strength low alloy steel has been carried out in order to establish a correlation amongst the parameters and to optimize the microstructural features and mechanical properties for superior wear performance. The steel was subjected to various heat treatment

A. K. Jha; B. K. Prasad; O. P. Modi; S. Das; A. H. Yegneswaran

2003-01-01

152

Effect of nitrogen alloying and the electroslag refining process on the properties of AISI M41 steel  

NASA Astrophysics Data System (ADS)

Nitrogen produces very beneficial effects in high-speed steel and can therefore be regarded as a significant alloying element in ferrous materials. In order to attain the goal of this study, to investigate the effect of nitrogen alloying and the electroslag refining (ESR) process on the properties of AISI M41 steel, two high-speed steels were melted in an air induction furnace (IF). The first one is a standard AISI M41 high-speed steel. The second one is nitrogen-alloyed M41. The produced ingots were used as consumable electrodes in ESR under three different CaF2-based fluxes. The steel produced from the IF and ESR was heat treated. Hardness, secondary hardness, and microstructure were also studied. It was concluded that both ESR and nitrogen alloying improve the hardness profile of the quenched-tempered high-speed steels. The highest secondary hardness and highest softening resistance were attained by ESR of high-nitrogen high-speed steel (M41N) under CaF2/CaO/Al2O3: 55/30/15 slag. The ESR improves the shape, size, and distribution of precipitates in the produced ingot. Quenching and tempering treatment conditions the retained austenite that is present in the as-cast steel by precipitation of carbide and forming martensite on cooling to room temperature.

Mattar, Taha; El Fawakhry, Kamal; Halfa, Hossam; El Demerdash, Mahmoud

2006-12-01

153

Effect of annealing prior to cold rolling on magnetic and mechanical properties of low carbon non-oriented electrical steels  

Microsoft Academic Search

The effects of annealing prior to cold rolling on the microstructure, magnetic and mechanical properties of low-C grain non-oriented (GNO) electrical steels have been investigated. The grain structure of hot-rolled electrical steel strips is modified by annealing at temperatures between 700 and 1050C. Annealing at temperatures less than the ferrite to austenite+ferrite transformation temperature on heating (Ac1) causes a marginal

E. J. Gutirrez-Castaeda; A. Salinas-Rodrguez

2011-01-01

154

Effect of high-temperature thermomechanical treatment on the mechanical properties of nitrogen-containing constructional steel  

Microsoft Academic Search

The effect of thermomechanical treatment on the structure and mechanical properties of the constructional steels (35 50)KhNMAF\\u000a micro-alloyed with nitrogen is studied. Tensile and impact tests are conducted, the HV hardness is measured, and the structure of the steel is investigated by means of light microscopy and X-diffraction analysis.\\u000a The regimes of thermal and thermomechanical treatment that make it

L. M. Kaputkina; V. G. Prokoshkina; A. G. Svyazhin; D. V. Kremyanskii; M. G. Medvedev; G. E. Khadeev

2010-01-01

155

Effect of continuous-cooling transformation structure on mechanical properties of 0.4C-Cr-Mo-Ni steel  

Microsoft Academic Search

Commercially available 0.4C-Cr-Mo-Ni steel was studied to determine the effects on its mechanical properties of various microstructures produced by continuous-cooling transformation after austenitization. A good combination of strength and notch toughness was obtained independently of test temperatures (293 and 193 K) when the steel was austenitized at 1173 K and then continuously cooled at an average rate of ~ 3.1

Yoshiyuki Tomita

1994-01-01

156

Microstructure and mechanical properties of weld fusion zones in modified 9Cr-1Mo steel  

NASA Astrophysics Data System (ADS)

Modified 9Cr-1Mo steel finds increasing application in power plant construction because of its excellent high-temperature properties. While it has been shown to be weldable and resistant to all types of cracking in the weld metal and heat-affected zone (HAZ), the achievement of optimum weld metal properties has often caused concern. The design of appropriate welding consumables is important in this regard. In the present work, plates of modified 9Cr-1Mo steel were welded with three different filler materials: standard 9Cr-1Mo steel, modified 9Cr-1Mo, and nickel-base alloy Inconel 182. Post-weld heat treatment (PWHT) was carried out at 730 and 760 C for periods of 2 and 6 h. The joints were characterized in detail by metallography. Hardness, tensile properties, and Charpy toughness were evaluated. Among the three filler materials used, although Inconel 182 resulted in high weld metal toughness, the strength properties were too low. Between modified and standard 9Cr-1Mo, the former led to superior hardness and strength in all conditions. However, with modified 9Cr-1Mo, fusion zone toughness was low and an acceptable value could be obtained only after PWHT for 6 h at 760 C. The relatively poor toughness was correlated to the occurrence of local regions of untransformed ferrite in the microstructure.

Sireesha, M.; Sundaresan, S.; Albert, Shaju K.

2001-06-01

157

Low-Density Steels: The Effect of Al Addition on Microstructure and Properties  

NASA Astrophysics Data System (ADS)

Density reduction of automotive steels is needed to reduce fuel consumption, thereby reducing greenhouse gas emissions. Aluminum addition has been found to be effective in making steels lighter. Such an addition does not change the crystal structure of the material. Steels modified with aluminum possess higher strength with very little compromise in ductility. In this work, different compositions of Fe-Al systems have been studied so that the desired properties of the material remain within the limit. A density reduction of approximately 10% has been achieved. The specific strength of optimal Fe-Al alloys is higher than conventional steels such as ultra-low-carbon steels.

Pramanik, Sudipta; Suwas, Satyam

2014-09-01

158

Influence of delta ferrite and dendritic carbides on the impact and tensile properties of a martensitic chromium steel  

NASA Astrophysics Data System (ADS)

Martensitic chrome steels with a high content of chromium incline to form delta ferrite frequently accompanied by massive dendritic carbide precipitations. Both phases mostly influence the mechanical properties of this steel in countercurrent manner. The relatively soft delta ferrite causes an increase of ductility and toughness, whilst the brittle dendritic carbides decreases both. Both phases mostly decrease the strength of the steel. One or the other influence will be dominant in dependence of the quantitative relation of the two phases. This is the cause for very different statements in the literature. The dendritic carbides should be avoided using a cooling rate of more than 10 3 K/min after the austenitization, because this phase mostly impairs the mechanical properties of the steel. However, the delta ferrite without dendritic carbides can be tolerated mostly.

Schfer, L.

1998-10-01

159

Effects of finishing rolling temperatures and reduction on the mechanical properties of hot rolled multiphase steel  

Microsoft Academic Search

Effects of finishing rolling temperatures and reduction on the mechanical properties of hot rolled multiphase steel were investigated.\\u000a Thermo-mechanical control processing (TMCP) was conducted by using a laboratory hot rolling mill, in which three different\\u000a kinds of finishing rolling temperatures and reduction and various austempering times were applied. The results showed that\\u000a polygonal ferrite, granular bainite and larger amount of

Zhuang Li; Di Wu

2007-01-01

160

Clay and DOPA containing polyelectrolyte multilayer film for imparting anticorrosion properties to galvanized steel.  

PubMed

A facile and green approach is developed to impart remarkable protection against corrosion to galvanized steel. A protecting multilayer film is formed by alternating the deposition of a polycation bearing catechol groups, used as corrosion inhibitors, with clay that induces barrier properties. This coating does not affect the esthetical aspect of the surface and does not release any toxic molecules in the environment. PMID:22200075

Faure, Emilie; Halusiak, Emilie; Farina, Fabrice; Giamblanco, Nicoletta; Motte, Ccile; Poelman, Mireille; Archambeau, Catherine; Van de Weerdt, Ccile; Martial, Joseph; Jrme, Christine; Duwez, Anne-Sophie; Detrembleur, Christophe

2012-02-01

161

Effects of aging at 475 C on corrosion properties of tungsten-containing duplex stainless steels  

Microsoft Academic Search

Effects of aging at 475 C on the corrosion and mechanical properties of Fe25Cr7Ni0.25NxMoyW (x=03, y=06) duplex stainless steels were investigated by an anodic polarization test in HCl solution, a modified double-loop electrochemical potentiodynamic reactivation (DL-EPR) test, and an impact test. Corrosion resistance of the alloys was degraded with aging at 475 C due to the depletion of Cr around

Chan-Jin Park; Hyuk-Sang Kwon

2002-01-01

162

Composition, microstructure, hardness, and wear properties of high-speed steel rolls  

Microsoft Academic Search

The effects of alloying elements on the microstructural factors, hardness, and wear properties of four high-speed steel (HSS)\\u000a rolls fabricated by centrifugal casting were investigated. A hot-rolling simulation test was carried out using a high-temperature\\u000a wear tester capable of controlling speed, load, and temperature. The test results revealed that the HSS roll containing a\\u000a larger amount of vanadium showed the

Joon Wook Park; Huo Choon Lee; Sunghak Lee

1999-01-01

163

Computational prediction of influence of ausforming on enhancement of mechanical properties of trip steels  

SciTech Connect

Transformation-induced plasticity (TRIP) steels possess such favorable mechanical properties as good work-hardening characteristics, tenacity and strength. The strain-induced martensitic transformation, however, strongly depends on the temperature, stress state and strain rate imposed, and the desired improvement of mechanical properties is realized only under fairly restricted circumstances. To elucidate the required mechanical properties, a constitutive model which can suitably predict the deformation behavior, including transformation, under wide ranges of deformation rate and temperature has been developed by generalizing the model by Stringfellow et al. to take into account strain rate sensitivity. Here, we focused on the prediction of the influence of ausforming on the mechanical characteristics of TRIP steels. To this end, we performed the computational simulation of the deformation behavior of a SUS304(18-8) cylinder under different environmental temperatures with different strain rates, by the thermocoupled finite element method, accounting for the latent heat induced by martensitic transformation. It has been clarified that preforming has the possibility of substantially increasing ductility and strength of TRIP steels deformed in a low temperature range. Since, the decrease of elongation at onset of instability {Epsilon}{sup 0n(max)} relative to that for the initial volume fraction of martensite {line_integral}{sup 0m}=0 decreases with environmental temperature, {line_integral}{sup 0m} due to cooling may contribute to the improvement of tensile strength {sigma}{sub B} during TRIP process in a low temperature range, without serious loss of ductility.

Tomita, Y.; Iwamoto, T. [Kobe Univ., Nada (Japan)

1995-12-31

164

Mechanical properties of 1950's vintage Type 304 stainless steel weldment components  

SciTech Connect

The primary coolant piping systems of the nuclear production reactors constructed in the 1950's at Savannah River Site are comprised of Type 304 stainless steel. A program has been completed which assessed the material properties of archival large diameter piping having approximately six years of service at temperatures between 25 and 125{degree}C. An extensive database of mechanical properties was produced for examination of material variability and to provide properties for engineering analysis, including piping fracture resistance assessment. Tensile properties, Charpy-V notch ductility, and elastic-plastic fracture toughness were established for base metal, weld metal and weld heat-affected-zone (HAZ) materials. A total of 375 mechanical specimens representing ASTM L-C and C-L orientations were tested at temperatures of 25 or 125{degree}C. The effect of dynamic loading on tensile and fracture toughness properties was also explored. The time-to-specimen maximum load ({approx}80 milliseconds) was chosen to simulate a seismic loading event. The mechanical properties of the vintage piping material were found typical of those of recently-produced commercial melts of Type 304 stainless steel piping and are consistent with ASME Code Section II design values. The toughness properties of welds fabricated by the Metal Inert Gas (MIG) welding process (multipass, Type 308 stainless steel filler), were found similar to the base materials, yielding a high fracture resistance. Practical applications of the mechanical properties database in piping fracture assessments are illustrated with the methodology for an elastic-plastic analysis. 10 refs., 9 figs., 8 tabs.

Stoner, K.J.; Sindelar, R.L.; Awadalla, N.G. (Westinghouse Savannah River Co., Aiken, SC (USA)); Hawthorne, J.R.; Hiser, A.L.; Cullen, W.H. (Materials Engineering Associates, Inc., Lanham, MD (USA))

1990-01-01

165

Molybdate adsorption from steel slag eluates by subsoils.  

PubMed

Steel slags are industrial by-products which are generated in large amounts worldwide, e.g. 150-23010(6) Mg in 2012, and which are partly used for construction. Molybdenum (Mo) can be added during steel processing in order to harden the steel. The objective of this study was to evaluate the adsorption behaviour of molybdate (MoO4(2-)) from slag eluates in subsoils. Molybdate batch adsorption experiments were carried out with eluates obtained from two different kinds of steel slags (i) LD slag (Linz-Donawitz operation, LDS) and (ii) electric arc furnace slag (EAF) to assess the risk that may arise from the contamination of groundwater by the leaching of molybdate. Six different subsoils were chosen in order to provide a wide range of chemical properties (pH 4.0-7.6; dithionite-extractable Fe 0.73-14.7 g kg(-1)). Molybdate adsorption experiments were carried out at the pH of the steel slag eluates (pH 11-12) as well as at pH values adjusted to the soil pH. The data were evaluated with the Freundlich equation. Molybdate adsorption exhibited a maximum near pH 4 for steel slag eluates adjusted to the soil pH, and decreased rapidly with increasing pH until adsorption was virtually zero at pH>11. Adsorption was greater for soils with high amounts of dithionite-extractable Fe oxides. The extent and behaviour of molybdate adsorption from both eluates was similar. After a reaction time of 24h, the pH of the EAF slag eluate was lower than that of the LD steel slag eluate, which was caused by different acid buffer capacities. Some soils were able to decrease the pH of the EAF slag eluates by about 4 pH units, enhancing the adsorption of molybdate. Transport simulations indicated that molybdate discharge is low in acidic soils. PMID:23973286

Matern, K; Rennert, T; Mansfeldt, T

2013-11-01

166

1D subsurface electromagnetic fields excited by energized steel casing  

E-print Network

1D subsurface electromagnetic fields excited by energized steel casing Wei Yang1 , Carlos Torres the possibility of enabling steel-cased wells as galvanic sources to detect and quantify spatial variations of electrical conductivity in the subsurface. The study assumes a vertical steel-cased well that penetrates

Torres-Verdn, Carlos

167

Microstructure-Mechanical Property Relationships for a Fe/Mn/Cr Rock Bolt Reinforcing Steel  

NASA Astrophysics Data System (ADS)

The influence of low chromium additions to a 0.25C-1.5Mn semikilled steel on microstructure, and tensile and impact behaviors of high strength rock bolt reinforcing bars has been investigated. Although chromium imparted adequate tensile properties at ambient temperature (yield stress: 624 MPa; ultimate tensile stress: 819 MPa; elongation: 12.5%) by forming transformation products such as tempered martensite, lower and upper bainite, and small amounts of acicular ferrite, it increased the ductile-to-brittle transition temperature due to coarser upper bainite in the core region of bar having larger unit crack paths. The synthesized steel is considered to be effective in realizing the desired tensile properties, and suitable for application in rock bolt, as well as other reinforced concrete structures.

Panigrahi, B. K.

2010-08-01

168

Elevated temperature mechanical properties of a reactor pressure vessel steel  

NASA Astrophysics Data System (ADS)

A testing program is in progress to define the tensile and creep properties of SA533 Grade B Class 1 steel at temperatures from 371 to 538 C. The overall objective is to provide the data necessary to obtain ASME Code approval for use of this material for the Modular High-Temperature Gas-Cooled Reactor (MHTGR) vessel during short-term temperature excursions above 371 C. Testing and evaluation involve three heats of base metal, two submerged arc welds, and a shielded metal arc weld. The creep strengths of the base metal heats and the weldments were found to be equivalent; the weld metal itself is slightly stronger. The data obtained indicate that stress to produce 1% strain will likely be the controlling factor in setting the allowable stresses for design.

McCoy, H. E.; Rittenhouse, P. L.

1990-04-01

169

EFFECT OF POROSITY ON MECHANICAL PROPERTIES OF 8630 CAST STEEL  

E-print Network

of steel castings. Likewise there are no guidelines relating non-destructive testing or non- destructive examination (NDT or NDE) methods such as radiography to the performance of cast steel components. Unless

Beckermann, Christoph

170

Mechanical properties and microstructure evolution of CLAM Steel in tube fabrication and test blanket module assembly  

NASA Astrophysics Data System (ADS)

The first wall of the China dual functional lithium lead-test blanket module (DFLL-TBM) will be assembled with China low activation martensitic (CLAM) steel rectangular tubes and plates by hot isostatic pressing (HIP) - diffusion welding. The objective of this study is to evaluate CLAM rectangular tubes and investigate mechanical property and microstructure evolution of CLAM steel in tube fabrication and TBM assembly. In this work, CLAM rectangular tubes with lengths of 1500 mm were fabricated, and the dimensional accuracy met the requirement for HIP joining. In the tube fabrication process, the CLAM steel was annealed to improve its ductility. In addition, the anisotropy in mechanical properties and microstructure introduced by tube rolling was eliminated according to the simulation of HIP heat treatment in TBM preparation. The tensile strength of the CLAM tubes with final heat treatment was slightly higher than that of CLAM steel with the published standard heat treatment, while the total elongation was reduced. This revealed that a post-HIP heat treatment was required before the final heat treatment. An annealing treatment at 1253 K transformed martensite to ferrite, decreased the tensile strength, and increase the ductility; Rolling deformation introduced microstructural anisotropy, increased the Vickers hardness, and created an inhomogeneous hardness distribution; A simulated HIP heat treatment schedule removed these differences in hardness and tensile strength due to the anisotropy; The tensile strength of CLAM tube material given the published standard heat treatment (with the simulated HIP heat treatment) was higher than that of previously published CLAM steel results and the elongation was reduced. Therefore, a post-HIP heat treatment for CLAM tube material appears to be required before applying a final heat treatment based on the prior standard heat treatment in order to preserve the overall tensile elongation.

Huang, Bo; Huang, Qunying; Li, Yanfen; Li, Chunjing; Wu, Qingsheng; FDS Team

2013-11-01

171

Properties of Galvanized and Galvannealed Advanced High Strength Hot Rolled Steels  

SciTech Connect

The objectives of the project were (i) to develop the coating process information to achieve good quality coatings on 3 advanced high strength hot rolled steels while retaining target mechanical properties, (ii) to obtain precise knowledge of the behavior of these steels in the various forming operations and (iii) to establish accurate user property data in the coated conditions. Three steel substrates (HSLA, DP, TRIP) with compositions providing yield strengths in the range of 400-620 MPa were selected. Only HSLA steel was found to be suitable for galnaizing and galvannealing in the hot rolled condition.

V.Y. Guertsman; E. Essadiqi; S. Dionne; O. Dremmailova; R. Bouchard; B. Voyzelle; J. McDermid; R. Fourmentin

2008-04-01

172

Fatigue Properties of Carburized Extra-fine Ni Steels  

Microsoft Academic Search

High compressibility Ni-Mo steels are leading candidate materials for high density PM steel gears. Recently developed admixed Ni-Mo steels containing extra-fine Ni powder limit the formation of soft Ni-rich austenitic phases thought to be detrimental for contact fatigue performance of PM steels. FLN2-4405 mixes containing both standard (STD Ni) and extra-fine Ni (XF Ni) powder were compacted into Charpy bars

T. F. Stephenson

173

Induction Steel: Inclusion Content and Mechanical Properties of Reinforcing Bars Produced from Pencil Ingots and Continuously Cast Billets  

NASA Astrophysics Data System (ADS)

In Bangladesh, most of the reinforcing bars are produced by rolling steel produced by melting scrap in induction furnaces. In many plants the molten steel is directly cast in vertical moulds into what are usually called `pencil ingots'. In some plants the molten steel is tapped into large ladles, taken to continuous casting machines and cast into continuous billets. In some cases the molten steel is refined in ladles (purged with nitrogen or argon) before casting into continuous billets. This investigation aims at a comparison of the inclusion content and resultant mechanical properties of reinforcing bars produced through these different routes. The samples for this study were collected from the process streams of a steel plant. The inclusion content was determined by direct measurement of inclusions on metallographic specimens and the mechanical properties were determined by using a universal tensile testing machine. Reinforcing bars produced by rolling ladle refined continuously cast billets have the lowest content of inclusion and the best mechanical (yield strength, ultimate tensile strength, percentage elongation, etc.) properties. The highest inclusion content and the worst properties were obtained in the pencil ingots.

Hossain, A.; Kurny, A. S. W.

2012-04-01

174

Adsorption properties and inhibition of mild steel corrosion in 15% HCl by 3-((1H-indol-3-yl)(4-methoxyphenyl)methyl)-1H-indole:electrochemical study  

NASA Astrophysics Data System (ADS)

The inhibiting effect of 3-((1H-indol-3-yl)(4-methoxyphenyl)methyl)-1H-indole (IMMI) on the corrosion of mild steel (MS) in 15% HCl solution has been studied by using potentiodynamic polarization technique. The polarization data revealed that IMMI acts as a mixed type inhibitor for mild steel in acid solution.. The adsorption of the inhibitors on the mild steel surface was found to obey Langmuir's adsorption isotherm. Inhibition efficiency was found to be greater than 95% and inhibition is governed by both physical adsorption and chemisorption mechanism.

Behera, Debasis; Kumar, Sushil; Sinha, Rajesh Ranjan; Yadav, Mahendra

2014-04-01

175

TRITIUM AGING EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF STAINLESS STEEL BASE METAL AND WELDS  

SciTech Connect

Tritium reservoirs are constructed from welded stainless steel forgings. While these steels are highly resistant to the embrittling effects of hydrogen isotopes and helium from tritium decay; they are not immune. Tritium embrittlement is an enhanced form of hydrogen embrittlement because of the presence of helium-3 from tritium decay which nucleates as nanometer-sized bubbles on dislocations, grain boundaries, and other microstructural defects. Steels with decay helium bubble microstructures are hardened and less able to deform plastically and become more susceptible to embrittlement by hydrogen and its isotopes. Ductility, elongation-to-failure, and fracture toughness are reduced by exposures to tritium and the reductions increase with time as helium-3 builds into the material from tritium permeation and radioactive decay. Material and forging specifications have been developed for optimal material compatibility with tritium. These specifications cover composition, mechanical properties, and select microstructural characteristics like grain size, flow-line orientation, inclusion content, and ferrite distribution. For many years, the forming process of choice for reservoir manufacturing was high-energy-rate forging (HERF), principally because the DOE forging facility owned only HERF hammers. Today, some reservoir forgings are being made that use a conventional, more common process known as press forging (PF or CF). One of the chief differences between the two forging processes is strain rate: Conventional hydraulic or mechanical forging presses deform the metal at 4-8 ft/s, about ten-fold slower than the HERF process. The material specifications continue to provide successful stockpile performance by ensuring that the two forging processes produce similar reservoir microstructures. While long-term life storage tests have demonstrated the general tritium compatibility of tritium reservoirs, fracture-toughness properties of both conventionally forged and high-energy-rate forged are needed for designing and establishing longer tritium-reservoir lifetimes, ranking materials, and, potentially, for qualifying new forging vendors or processes. Measurements on the effects of tritium and decay helium on the fracture toughness properties of CF stainless steels having similar composition, grain size, and mechanical properties to previously studied HERF steels are needed and have not been conducted until now. The compatibility of stainless steel welds with tritium represents another concern for long-term reservoir performance. Weldments have not been well-characterized with respect to tritium embrittlement, although a recent study was completed on the effect of tritium and decay helium on the fracture toughness properties of Type 304L weldments. This study expands the characterization of weldments through measurements of tritium and decay helium effects on the fracture toughness properties of Type 21-6-9 stainless steel. The purpose of this study was to measure and compare the fracture toughness properties of Type 21-6-9 stainless steel for conventional forgings and weldments in the non-charged, hydrogen-charged and tritium-charged-and-aged conditions.

Morgan, M.

2009-07-30

176

Change in structure and properties of carbon steels bombarded by a 10 ?5 to 10 ?4 second high-energy electron beam  

Microsoft Academic Search

We consider the hardening characteristics and features of the structural and phase transformations in carbon steel (0.7% C) quenched from the melt using an electron beam with electron energy 130180 keV, pulse duration 10200 msec and power density 106 to 107 W\\/cm2. We have observed that maximum hardening is achieved for pulse duration ?40 msec. The nonmonotonic character of the

Yu. F. Ivanov; I. S. Kashinskaya; S. V. Lykov; A. B. Markov; E. M. Oks; V. P. Potshtein

1995-01-01

177

Change in structure and properties of carbon steels bombarded by a 10-5 to 10-4 second high-energy electron beam  

Microsoft Academic Search

We consider the hardening characteristics and features of the structural and phase transformations in carbon steel (0.7% C) quenched from the melt using an electron beam with electron energy 130 180 keV, pulse duration 10 200 msec and power density 106 to 107 W\\/cm2. We have observed that maximum hardening is achieved for pulse duration ⋍40 msec. The nonmonotonic character

Yu. F. Ivanov; I. S. Kashinskaya; S. V. Lykov; A. B. Markov; E. M. Oks; V. P. Potshtein

1995-01-01

178

Nondestructive detection of embrittlement by copper in steel  

NASA Astrophysics Data System (ADS)

Copper can be used as an alloying element to increase the strength and hardness of steel. However, it can also act as an embrittling agent under certain circumstances. In particular, the decrease in fracture toughness of reactor pressure vessels following long term exposure to neutrons has been blamed on the formation of very small copper rich precipitates (CRPs) in the iron lattice. In order to develop a nondestructive technique for detecting these CRPs and for predicting the onset of embrittlement, several ultrasonic and magnetic properties have been measured on a high strength, low alloy steel containing 1.1 mass % copper in which the CRPs could be formed by proper heat treatments. The particular properties measured were the longitudinal and shear wave velocities and their associated internal frictions as well as the acoustic nonlinearity parameter, ?. The magnetic properties were the coercive force, the saturation magnetization, a dynamic permeability, ??, and the magnetostrictive coefficient, ?. Small angle neutron scattering studies confirmed that CRPs were formed during the heat treatments used and that their presence could be correlated with observed changes in hardness. These hardness changes could then be correlated with some of the physical properties that were measured.

Alers, G.; Balzar, D.; Hurley, D.; Igarashi, B.; Fickett, F.; Kim, S.; Ledbetter, H.; Purtscher, P.

1999-12-01

179

Thermophysical Properties of a Hot-Work Tool-Steel with High Thermal Conductivity  

NASA Astrophysics Data System (ADS)

In the highly productive permanent mold-casting process, the released enthalpy of the solidifying metal has to be transported through the surrounding hot-work tool-steel to the cooling system. For that reason, the thermal conductivity is a key property of the employed tool-steel. Recently, a new type of steel (Rovalma HTCS 130) has been developed and superior thermal properties have been claimed. In this study, measurements of the thermal diffusivity, heat capacity, and thermal expansion as a function of temperature are described for this steel and results of the computed thermal conductivity are reported. There is quite a discrepancy between the specification of the steel supplier and the results of this study; however, an improvement of the thermal conductivity for this type of steel can be confirmed.

Kaschnitz, E.; Hofer, P.; Funk, W.

2013-05-01

180

The effect of carbon concentration and plastic deformation on ultrasonic higher order elastic properties of steel  

NASA Technical Reports Server (NTRS)

The behavior of higher order elastic properties, which are much more sensitive to material state than are second order properties, has been studied for steel alloys AISI 1016, 1045, 1095, and 8620 by measuring the stress derivative of the acoustic natural velocity to determine the stress acoustic constants (SAC's). Results of these tests show a 20 percent linear variation of SAC's with carbon content as well as even larger variations with prestrain (plastic deformation). The use of higher order elastic characterization permits quantitative evaluation of solids and may prove useful in studies of fatigue and fracture.

Heyman, J. S.; Allison, S. G.; Salama, K.

1985-01-01

181

Effect of thermal cycling on the mechanical properties of 350-grade maraging steel  

SciTech Connect

The effects of retained austenite produced by thermal cycling on the mechanical properties of a precipitation-hardened 350-grade commercial maraging steel were examined. The presence of retained austenite caused decreases in the yield strength (YS) and ultimate tensile strength (UTS) and effected a significant increase in the tensile ductility. Increased impact toughness was also produced by this treatment. The mechanical stability of retained austenite was evaluated by tension and impact tests at subambient temperatures. A deformation-induced transformation of the austenite was manifested as load drops on the load-elongation plots at subzero temperatures. This transformation imparts excellent low-temperature ductility to the material. A wide range of strength, ductility, and toughness can be obtained by subjecting the steel to thermal cycling before the precipitation-hardening treatment.

Viswanathan, U.K.; Kishore, R. [Bhabha Atomic Research Centre, Bombay (India); Asundi, M.K. [Vibha, Bombay (India)

1996-03-01

182

The Effects of Martensite Content on the Mechanical Properties of Quenched and Tempered 0.2%C-Ni-Cr-Mo Steels  

Microsoft Academic Search

Three martensite contents (approximately 35, 50, and 100%) were obtained in a SAE8822 steel by altering the quenching media and section size. Another variation in martensite content (approximately 80 versus 97%) was achieved by quenching a SAE8622 steel in the same section size. The impact toughness and fatigue properties were determined after tempering to various levels of monotonic strength. Toughness

John M. Tartaglia

2010-01-01

183

Evaluation of Microstructural, Mechanical Properties and Corrosion Behavior of AISI Type 316LN Stainless Steel and Modified 9Cr-1Mo Steel Exposed in a Dynamic Bimetallic Sodium Loop at 798 K (525 C) for 16,000 Hours  

NASA Astrophysics Data System (ADS)

Changes occurring in the chemical composition, microstructure, mechanical properties, and carburization behavior of type 316LN stainless steel and modified 9Cr-1Mo steel on exposure to flowing sodium at 798 K (525 C) for 16,000 hours in a bimetallic loop are discussed in this article. Type 316LN stainless steel revealed a degraded layer of approximately 5 ?m depth. No significant microstructural changes were observed in the case of modified 9Cr-1Mo steel exposed to sodium. The carburization depth in type 316LN stainless steel was approximately 100 ?m and the surface carbon concentration was 0.374 wt pct. In the case of modified 9Cr-1Mo steel, the carbon concentration at the surface was approximately 3.50 wt pct and the depth of carburization was nearly 75 ?m. The concentration of nickel and chromium decreased from the bulk to the surface of type 316LN stainless steel, leading to the formation of a ferrite layer. The concentration of these two elements reached the original matrix concentration at around 30 ?m. Sodium-exposed material indicated an increase in yield strength by 10 pct and reduction in ductility by 34 pct vis--vis annealed material. No such changes in strength and ductility were observed in the case of modified 9Cr-1Mo steel. A decrease in impact energy was noticed for sodium-exposed type 316LN stainless steel and modified 9Cr-1Mo steel vis--vis as-received material.

Sivai Bharasi, N.; Thyagarajan, K.; Shaikh, H.; Radhika, M.; Balamurugan, A. K.; Venugopal, S.; Moitra, A.; Kalavathy, S.; Chandramouli, S.; Tyagi, A. K.; Dayal, R. K.; Rajan, K. K.

2012-02-01

184

Structure and properties of steel R6M5 after thermomechanical treatment  

Microsoft Academic Search

A positive effect of low-temperature thermomechanical treatment (LTMT) on the strength, hardness, resistance to cold abrasion, fatigue strength, and cutting properties of high-speed steels was found in [4-7]. However, this method is not used in industry due to the low ductility of high-speed steels in the LTMT temperature range (400-600C). High-temperature thermomechanical treatment (HTMT) is not used for high-speed steels

I. K. Kupalova

1980-01-01

185

Influence of thermomechanical treatment on microstructure and mechanical properties of Nb bearing weather resistant steel  

Microsoft Academic Search

The influence of thermomechanical treatment on the structure and properties of a Nb bearing weather resistant steel has been studied. The steel contains 0.11% C, 0.024% Nb, 0.3% Ni and 0.45% Cr and Cu each. It has been found that the YS, UTS and hardness of rolled steel increase with increasing soaking temperature. However, increasing the rolling deformation results in

S. N. Prasad; D. S. Sarma

2005-01-01

186

The influence of Cr content on the mechanical properties of ODS ferritic steels  

NASA Astrophysics Data System (ADS)

The present investigation aimed at researching the mechanical properties of the oxide dispersion strengthened (ODS) ferritic steels with different Cr content, which were fabricated through a consolidation of mechanical alloyed (MA) powders of 0.35 wt.% nano Y2O3 dispersed Fe-12.0Cr-0.5Ti-1.0W (alloy A), Fe-16.0Cr-0.5Ti-1.0W (alloy B), and Fe-18.0Cr-0.5Ti-1.0W (alloy C) alloys (all in wt.%) by hot isostatic pressing (HIP) with 100 MPa pressure at 1150 C for 3 h. The mechanical properties, including the tensile strength, hardness, and impact fracture toughness were tested by universal testers, while Young's modulus was determined by ultrasonic wave non-destructive tester. It was found that the relationship between Cr content and the strength of ODS ferritic steels was not a proportional relationship. However, too high a Cr content will cause the precipitation of Cr-enriched segregation phase, which is detrimental to the ductility of ODS ferritic steels.

Li, Shaofu; Zhou, Zhangjian; Jang, Jinsung; Wang, Man; Hu, Helong; Sun, Hongying; Zou, Lei; Zhang, Guangming; Zhang, Liwei

2014-12-01

187

Effect of long-term thermal aging on magnetic property in reactor pressure vessel steels  

NASA Astrophysics Data System (ADS)

Effect of long-term thermal aging at 290 and 500 C on magnetic hysteresis property in reactor pressure vessel steels and simple model alloys have been investigated for times up to 8800 h. While Vickers hardness is insensitive to thermal aging at both temperatures, coercivity generally exhibits a slight decrease after aging at 290 C. In particular, at a higher temperature of 500 C a steady increase of coercivity was observed for reactor pressure vessel steels, whereas coercivity for simple model alloys exhibits an abrupt drop just after aging and the decrease was 20-30% of that before aging. The results were interpreted by the thermally-assisted formation of Cu-rich precipitates and recovery, but the latter has the dominant effect for simple model alloys because of their ferritic microstructure. The possible effect of relaxation of lattice strain created by dissolved interstitial atoms during neutron irradiation is proposed.

Kobayashi, S.; Sato, H.; Iwawaki, T.; Yamamoto, T.; Klingensmith, D.; Odette, G. R.; Kikuchi, H.; Kamada, Y.

2013-08-01

188

TRITIUM AGING EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF FORGED STAINLESS STEEL  

SciTech Connect

The fracture toughness properties of Type 21-6-9 stainless steel were measured for forgings in the unexposed, hydrogen-exposed, and tritium-exposed-and-aged conditions. Fracture toughness samples were cut from conventionally-forged and high-energy-rate-forged forward-extruded cylinders and mechanically tested at room temperature using ASTM fracture-toughness testing procedures. Some of the samples were exposed to either hydrogen or tritium gas (340 MPa, 623 K) prior to testing. Tritium-exposed samples were aged for up to seven years and tested periodically in order to measure the effect on fracture toughness of {sup 3}He from radioactive tritium decay. The results show that hydrogen-exposed and tritium-exposed samples had lower fracture- toughness values than unexposed samples and that fracture toughness decreased with increasing decay {sup 3}He content. Forged steels were more resistant to the embrittling effects of tritium and decay {sup 3}He than annealed steels, although their fracture-toughness properties depended on the degree of sensitization that occurred during processing. The fracture process was dominated by microvoid nucleation, growth and coalescence; however, the size and spacing of microvoids on the fracture surfaces were affected by hydrogen and tritium with the lowest-toughness samples having the smallest microvoids and finest spacing.

Morgan, M

2008-04-14

189

Stochastic Modeling of Soft Magnetic Properties of Electrical Steels: Application to Stators of Electrical Machines  

E-print Network

1 Stochastic Modeling of Soft Magnetic Properties of Electrical Steels: Application to Stators of the electrical steel sheet depends on the mechanical stress and the direction of the magnetic field excitation of Electrical Machines R.Ramarotafika1,2 , A.Benabou2 , S.Clnet1 1 L2EP/Arts et Mtiers ParisTech, Centre de

Paris-Sud XI, Universit de

190

Influence of carbon, manganese and nickel on microstructure and properties of strong steel  

E-print Network

Influence of carbon, manganese and nickel on microstructure and properties of strong steel weld strength steel weld metal with 7 wt-% nickel and 0.5 wt-% manganese could be increased significantly metal, Nickel, Manganese, Strength, Impact toughness, Carbon, Bainite, Martensite, Microstructure

Cambridge, University of

191

Understanding Mechanical Properties of Novel High Strength Steel Weld Metals Through High-Resolution Microstructural Investigations  

E-print Network

Understanding Mechanical Properties of Novel High Strength Steel Weld Metals Through High such steels must be joined with care with particular attention placed on welding parameters, if both strength) with a compatible experimental composition was also investigated. Experimental procedures Welded joints were made

Cambridge, University of

192

Effects of carbon on microstructures and properties of high vanadium high-speed steel  

Microsoft Academic Search

The effects of carbon content on the microstructures, mechanical properties and wear behavior of high vanadium (10%) high speed steel were studied systemically. The results show that the carbides in high vanadium high speed steel are composed of the vanadium carbide, small amount of Cr composite carbide and Mo composite carbide. With the increase of the carbon content, the amount

Shizhong Wei; Zhu Jinhua; Xu Liujie; Long Rui

2006-01-01

193

Characterization of microstructures and mechanical properties of Inconel 617\\/310 stainless steel dissimilar welds  

Microsoft Academic Search

The microstructure and mechanical properties of Inconel 617\\/310 austenitic stainless steel dissimilar welds were investigated in this work. Three types of filler materials, Inconel 617, Inconel 82 and 310 austenitic stainless steels were used to obtain dissimilar joint using the gas tungsten arc welding process. Microstructural observations showed that there was no evidence of any possible cracking in the weldments

H. Shah Hosseini; M. Shamanian; A. Kermanpur

2011-01-01

194

Factors Affecting on Mechanical Properties of Soft Martensitic Stainless Steel Castings  

Microsoft Academic Search

This paper details the factors affecting mechanical properties of soft martensitic stainless steel castings that have lower carbon contents and increased nickel contents of up to 6% compared with normal martensitic stainless steel castings. The effect of alloying elements and impurities on the microstructural features and tempering characteristics was considered in detail, with special reference to reverted austenite and temper

Yoshitaka Iwabuchi

2003-01-01

195

Mechanical property and irradiation damage of China Low Activation Martensitic (CLAM) steel  

NASA Astrophysics Data System (ADS)

China Low Activation Martensitic (CLAM) steel is being studied to develop the structural materials for a fusion reactor, which has been designed based on the well-known 9Cr1.5WVTa steel. The effect of tempering temperature on hardness and microstructure of CLAM steel was studied. The strength of CLAM steel increased by adding silicon, and the ductility remained constant. Conversely, while CLAM steel maintained good ductility with the addition of yttrium, its tensile strengths were greatly degraded. Behaviors under electron irradiation of CLAM steel were examined using the high voltage electron microscope. Electron irradiation at 450C formed many voids in CLAM steel with basic composition, whereas CLAM with silicon steel did not change the microstructure significantly.

Zhu, YanYong; Wan, FaRong; Gao, Jin; Han, WenTuo; Huang, YiNa; Jiang, ShaoNing; Qiao, JianSheng; Zhao, Fei; Yang, ShanWu; Ohnuki, Somei; Hashimoto, Naoyuki

2012-11-01

196

THE EFFECTS OF HYDROGEN, TRITIUM, AND HEAT TREATMENT ON THE DEFORMATION AND FRACTURE TOUGHNESS PROPERTIES OF STAINLESS STEEL  

SciTech Connect

The deformation and fracture toughness properties of forged stainless steels pre-charged with tritium were compared to the deformation and fracture toughness properties of the same steels heat treated at 773 K or 873 K and precharged with hydrogen. Forged stainless steels pre-charged with tritium exhibit an aging effect: Fracture toughness values decrease with aging time after precharging because of the increase in concentration of helium from tritium decay. This study shows that forged stainless steels given a prior heat treatment and then pre-charged with hydrogen also exhibit an aging effect: Fracture toughness values decrease with increasing time at temperature. A microstructural analysis showed that the fracture toughness reduction in the heat-treated steels was due to patches of recrystallized grains that form within the forged matrix during the heat treatment. The combination of hydrogen and the patches of recrystallized grains resulted in more deformation twinning. Heavy deformation twinning on multiple slip planes was typical for the hydrogen-charged samples; whereas, in the non-charged samples, less twinning was observed and was generally limited to one slip plane. Similar effects occur in tritium pre-charged steels, but the deformation twinning is brought on by the hardening associated with decay helium bubbles in the microstructure.

Morgan, M.; Tosten, M.; Chapman, G.

2013-09-06

197

Electromagnetic method for analyzing the property of steel casing  

SciTech Connect

It has been shown that electromagnetic (EM) imaging, in particular in borehole applications, can be effective in characterizing and monitoring subsurface processes involved in improved oil recovery operations and production management. In this report the authors present an innovative EM method for extracting information about a steel casing in terms of its electrical conductivity, magnetic permeability, and the casing thickness. The method is based on accurate evaluation of magnetic fields near the transmitting loop in a steel-cased borehole, and the least squares inversion of thus measured data. The need to make measurements close to the source stems from the two related considerations. One reason is that by making measurements close to the transmitter one can keep the formation response from entering the measurement to a minimum. The other reason concerns with the practical consideration involved in fabricating a borehole tool. The measurement accuracy in terms of PPM to the primary field can best be achieved when the transmitter and receiver are close to each other. To facilitate this requirement one can consider a single loop acting as the source and the receiver operating in time domain, or a closely coupled frequency-domain system with the source-receiver separation of just a few inches apart. Results are discussed.

Lee, K.H.; Kim, H.J.; Song, Y.

1998-02-01

198

Influence of nickel and molybdenum on the phase stability and mechanical properties of maraging steels  

SciTech Connect

The effect of nickel and molybdenum concentrations on the phase transformation and mechanical properties of conventional 10Ni(350) maraging steel has been investigated. Both of these elements act as strong austenite stabilizers. When the concentration of molybdenum or nickel is greater than 7.5 or 24 wt%, respectively, the austenite phase remains stable up to room temperature. In both molybdenum- and nickel-alloyed steels, the austenite phase could be transformed to martensite by either dipping the material in liquid nitrogen or subjecting it to cold working. When 7.5 wt% Mo and 24 wt% Ni were added in combination, however, the austenite phase obtained at room temperature did not transform to martensite when liquid-nitrogen quenched or even when cold rolled to greater than 95% reduction. The aging response of these materials has also been investigated using optical, scanning electron, and scanning transmission electron microscopy.

Ahmed, M.; Nasim, I.; Husain, S.W. (Dr. A.Q. Khan Research Labs., Rawalpindi (Pakistan))

1994-04-01

199

Corrosion properties of S-phase layers formed on medical grade austenitic stainless steel.  

PubMed

The corrosion properties of S-phase surface layers formed in AISI 316LVM (ASTM F138) and High-N (ASTM F1586) medical grade austenitic stainless steels by plasma surface alloying with nitrogen (at 430C), carbon (at 500C) and both carbon and nitrogen (at 430C) has been investigated. The corrosion behaviour of the S-phase layers in Ringer's solutions was evaluated using potentiodynamic and immersion corrosion tests. The corrosion damage was evaluated using microscopy, hardness testing, inductive coupled plasma mass spectroscopy and X-ray diffraction. The experimental results have demonstrated that low-temperature nitriding, carburising and carbonitriding can improve the localised corrosion resistance of both industrial and medical grade austenitic stainless steels as long as the threshold sensitisation temperature is not reached. Carburising at 500C has proved to be the best hardening treatment with the least effect on the corrosion resistance of the parent alloy. PMID:22160745

Buhagiar, Joseph; Dong, Hanshan

2012-02-01

200

Effect of Welding Current on the Structure and Properties of Resistance Spot Welded Dissimilar (Austenitic Stainless Steel and Low Carbon Steel) Metal Joints  

NASA Astrophysics Data System (ADS)

1.5 mm thick sheet metal coupons of austenitic stainless steel and plain low carbon steel were welded by resistance spot welding technique. The effects of welding current in the range 3-9 kA on the structure and mechanical properties of welded joint were investigated. The structure was studied by macroscopic, microscopic and scanning electron microscopy techniques. Mechanical properties were determined by tensile testing and microhardness measurements. Asymmetrical shape weld nugget was found to have formed in the welded joint which increased in size with an increase in welding current. The fusion zone showed cast structure with coarse columnar grain and dendritic with excess delta ferrite in austenitic matrix. Microhardness of the weld nugget was maximum because of martensite formation. An increase in welding current also increased tensile strength of the weld coupon. An attempt has also been made to relate the mode of fracture with the welding current.

Shawon, M. R. A.; Gulshan, F.; Kurny, A. S. W.

2015-04-01

201

Microstructural Characterization and Mechanical Performance of Hot Work Tool Steel Processed by Selective Laser Melting  

NASA Astrophysics Data System (ADS)

Microstructural characterization of hot work tool steel processed by selective laser melting was carried out. The findings shed light on the interrelationship between processing parameters and the microstructural evolution. It was found that the microstructure after layer-wise processing partially consists of metastable-retained austenite which transforms to martensite in a subsequent tensile test. This improves the mechanical properties of the hot work tool steel enabling direct application.

Holzweissig, Martin Joachim; Taube, Alexander; Brenne, Florian; Schaper, Mirko; Niendorf, Thomas

2015-01-01

202

Control of intermetallic compound layers at interface between steel and aluminum by diffusion-treatment  

Microsoft Academic Search

The toughening of FeAl intermetallic compound coating formed by aluminizing of carbon steel was investigated. The growth mechanism, morphology and mechanical properties of FeAl intermetallic compound layers on the surface of carbon steel were systematically evaluated for specimens diffused at temperatures ranging from 873 to 1323 K after hot dip aluminizing. Fe2Al5 was mainly formed on the specimen surfaces at

Shigeaki Kobayashi; Takao Yakou

2002-01-01

203

Corrosion resistance of sintered duplex stainless steel evaluated by electrochemical method  

Microsoft Academic Search

Purpose: of this paper was to examine the corrosion resistance of duplex stainless steels using electrochemical methods in 1M NaCl solution. The influence of powder mixes preparation and cooling cycle after sintering on corrosion properties was evaluated. Design\\/methodology\\/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, martensitic base powders by controlled addition of alloying

L. A. Dobrza?ski a; Z. Brytan; M. Actis Grande; M. Rosso

204

Influence of Martensite Mechanical Properties on Failure Mode and Ductility of Dual-Phase Steels  

NASA Astrophysics Data System (ADS)

The effects of the mechanical properties of the martensite phase on the failure mode and ductility of dual-phase (DP) steels are investigated using a micromechanics-based finite element method. Actual microstructures of DP steels obtained from scanning electron microscopy (SEM) are used as representative volume elements (RVEs) in the finite element calculations. Ductile failure of the RVE is predicted as plastic strain localization during the deformation process. Systematic computations are conducted on the RVE to quantitatively evaluate the influence of the martensite mechanical properties and volume fraction on the macroscopic mechanical properties of DP steels. These properties include the ultimate tensile strength (UTS), ultimate ductility, and failure modes. The computational results show that, as the strength and volume fraction of the martensite phase increase, the UTS of DP steels increases, but the UTS strain and failure strain decrease. In addition, shear-dominant failure modes usually develop for DP steels with lower martensite strengths, whereas split failure modes typically develop for DP steels with higher martensite strengths. The methodology and data presented in this article can be used to tailor DP steel design for its intended purposes and desired properties.

Choi, K. S.; Liu, W. N.; Sun, X.; Khaleel, M. A.

2009-04-01

205

Influence of Prior Fatigue Damage on Tensile Properties of 316L(N) Stainless Steel and Modified 9Cr-1Mo Steel  

NASA Astrophysics Data System (ADS)

In the current study, the effect of prior low-cycle fatigue (LCF) damage on the tensile properties of 316L(N) stainless steel (SS) and modified 9Cr-1Mo steel were systematically investigated. The LCF tests were interrupted at 5, 10, 30, and 50 pct of the total fatigue life followed by tensile tests on the same specimens at the same strain rate (3 10-3 s-1) and temperatures of 300 K, 823 K, and 873 K (27 C, 550 C, and 600 C). Prior strain cycling at elevated temperatures had remarkable effect on the tensile properties of both cyclically hardening and cyclically softening materials. An exponential relationship between the yield stress and the amount of pre-strain cycles is obtained for both the materials. The initial drastic change in the yield strength values up to 10 pct of fatigue life may be due to the microstructural changes that lead to hardening or softening in 316L(N) SS and modified 9Cr-1Mo steel, respectively. Saturation in the yield strength values beyond 10 pct of fatigue life has practical importance for remnant fatigue life assessment. Evolution of fatigue damage in both the 316L(N) SS and modified 9Cr-1Mo steel was analyzed using the surface replica technique.

Mariappan, K.; Shankar, Vani; Sandhya, R.; Mathew, M. D.; Bhaduri, A. K.

2015-02-01

206

Phase transformation and impact properties in the experimentally simulated weld heat-affected zone of a reduced activation ferritic/martensitic steel  

NASA Astrophysics Data System (ADS)

In this work, the phase transformation and impact properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic (RAFM) steel are investigated. The HAZs were experimentally simulated using a Gleeble simulator. The base steel consisted of tempered martensite through normalizing at 1000 C and tempering at 750 C, while the HAZs consisted of martensite, ?-ferrite and a small volume of autotempered martensite. The impact properties using a Charpy V-notch impact test revealed that the HAZs showed poor impact properties due to the formation of martensite and ?-ferrite as compared with the base steel. In addition, the impact properties of the HAZs further deteriorated with an increase in the ?-ferrite fraction caused by increasing the peak temperature. The impact properties of the HAZs could be improved through the formation of tempered martensite after post weld heat treatment (PWHT), but they remained lower than that of the base steel because the ?-ferrite remained in the tempered HAZs.

Moon, Joonoh; Lee, Chang-Hoon; Lee, Tae-Ho; Jang, Min-Ho; Park, Min-Gu; Han, Heung Nam

2014-12-01

207

Influence of Martensite Mechanical Properties on Failure Mode and Ductility of Dual Phase Steels  

SciTech Connect

In this paper, the effects of the mechanical properties of the martensite phase on the failure mode and ductility of dual phase (DP) steels are investigated using a micromechanics-based finite element method. Actual microstructures of DP sheet steels obtained from scanning electron microscopy are used as representative volume element (RVE) in two-dimensional plane-stress finite element calculations. Failure is predicted as plastic strain localization in the RVE during deformation. The mechanical properties of the ferrite and martensite phases in a commercial DP 980 steel are obtained based on the in-situ X-ray diffraction measurements of a uniaxial tensile test. Computations are then conducted on the RVE in order to investigate the influence of the martensite mechanical properties and volume fraction on the macroscopic behavior and failure mode of DP steels. The computations show that, as the strength and volume fraction of the martensite phase increase, the ultimate tensile strength (UTS) of DP steels increases but the UTS strain and failure strain decrease. These results agree well with the general experimental observations on DP steels. Additionally, shear dominant failure modes usually develop for DP steels with lower martensite strengths, whereas split failure modes typically develop for DP steels with higher martensite strengths.

Choi, Kyoo Sil; Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.

2009-04-01

208

Effects of manufacturing process on impact properties and microstructures of ODS steels  

NASA Astrophysics Data System (ADS)

Oxide dispersion strengthened (ODS) steels are notable advanced alloys with durability to a high-temperature and high-dose neutron irradiation environment because of their good swelling resistance and mechanical properties under neutron irradiation. 9-12Cr-ODS martensite steels have been developed in the Japan Atomic Energy Agency as the primary candidate material for the fast reactor fuel cladding tubes. They would also be good candidates for the fusion reactor blanket material which is exposed to high-dose neutron irradiation. In this work, modification of the manufacturing process of 11Cr-ODS steel was carried out to improve its impact property. Two types of 11Cr-ODS steels were manufactured: pre-mix and full pre-alloy ODS steels. Miniature Charpy impact tests and metallurgical observations were carried out on these steels. The impact properties of full pre-alloy ODS steels were shown to be superior to those of pre-mix ODS steels. It was demonstrated that the full pre-alloy process noticeably improved the microstructure homogeneity (i.e. reduction of inclusions and pores).

Tanno, Takashi; Ohtsuka, Satoshi; Yano, Yasuhide; Kaito, Takeji; Tanaka, Kenya

2014-12-01

209

Processing and properties of extruded tungsten-hafnium and tungsten-steel composites  

SciTech Connect

The purpose of this study was to evaluate the processing behavior and properties of tungsten-hafnium (W-Hf) and W-steel composites produced by hot extrusion of canned powders. The W-Hf composite was consolidated by extrusion of blended powders with preheat temperatures over the temperature range of 1100 to 1400{degrees}C. All extrusions produced fully dense material which exhibits elongation of the tungsten phase within the hafnium matrix. The flow stress, as characterized by the extrusion constant, decreases with increasing temperature up to 1300{degrees}C and increases substantially at 1400{degrees}C as significant quantities of intermetallic phase are formed during preheating. The room-temperature (RT) hardness and compressive yield stress increase modestly with increased extrusion ratio and are not affected by extrusion temperature in the range 1100 to 1300{degrees}C. The microstructures are essentially fully recrystallized at the 1300{degrees}C preheat temperature and partially recrystallized at lower temperatures. Additionally, a mixture of tungsten and steel powder was consolidated to full density by hot extrusion at a 1000{degrees}C preheat temperature and a reduction ratio of 4.2. Increased reduction of the W-steel composite results in increased RT hardness.

Ohriner, E.K.; Sikka, V.K. [Oak Ridge National Lab., TN (United States); Kapoor, D. [Army Armament Research and Development Engineering Center, Dover, NJ (United States)

1995-02-01

210

Tribological properties of nitrogen implanted and boron implanted steels  

SciTech Connect

Samples of a steel with high chrome content was implanted separately with 75 keV nitrogen ions and with 75 keV boron ions. Implanted doses of each ion species were 2-, 4-, and 8 {times} 10{sup 17}/cm{sup 2}. Retained doses were measured using resonant non-Rutherford Backscattering Spectrometry. Tribological properties were determined using a pin-on-disk test with a 6-mm diameter ruby pin with a velocity of 0.94 m/min. Testing was done at 10% humidity with a load of 377 g. Wear rate and coefficient of friction were determined from these tests. While reduction in the wear rate for nitrogen implanted materials was observed, greater reduction (more than an order of magnitude) was observed for boron implanted materials. In addition, reduction in the coefficient of friction for high-dose boron implanted materials was observed. Nano-indentation revealed a hardened layer near the surface of the material. Results from grazing incidence x-ray diffraction suggest the formation of Fe{sub 2}N and Fe{sub 3}N in the nitrogen implanted materials and Fe{sub 3}B in the boron implanted materials. Results from transmission electron microscopy will be presented.

Kern, K.T. [Norfolk State Univ., VA (United States). Center for Materials Research; Walter, K.C.; Griffin, A.J. Jr.; Kung, H.; Lu, Y.; Nastasi, M.; Tesmer, J.R. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.; Fayeulle, S. [Ecole Centrale De Lyon, Ecully (France)

1996-06-01

211

Creation of superhydrophobic stainless steel surfaces by acid treatments and hydrophobic film deposition.  

PubMed

In this work, we present a method to render stainless steel surfaces superhydrophobic while maintaining their corrosion resistance. Creation of surface roughness on 304 and 316 grade stainless steels was performed using a hydrofluoric acid bath. New insight into the etch process is developed through a detailed analysis of the chemical and physical changes that occur on the stainless steel surfaces. As a result of intergranular corrosion, along with metallic oxide and fluoride redeposition, surface roughness was generated on the nano- and microscales. Differences in alloy composition between 304 and 316 grades of stainless steel led to variations in etch rate and different levels of surface roughness for similar etch times. After fluorocarbon film deposition to lower the surface energy, etched samples of 304 and 316 stainless steel displayed maximum static water contact angles of 159.9 and 146.6, respectively. However, etching in HF also caused both grades of stainless steel to be susceptible to corrosion. By passivating the HF-etched samples in a nitric acid bath, the corrosion resistant properties of stainless steels were recovered. When a three step process was used, consisting of etching, passivation and fluorocarbon deposition, 304 and 316 stainless steel samples exhibited maximum contact angles of 157.3 and 134.9, respectively, while maintaining corrosion resistance. PMID:22913317

Li, Lester; Breedveld, Victor; Hess, Dennis W

2012-09-26

212

Structure and properties of Ni-Cr-Mo-V-rotor steels  

Microsoft Academic Search

on the structure and mechanical properties of rotor steels of the types 25KhN3MFA, 35KhN3MFA, and 12KhN3MFA (Table i). Cobalt, whose addition promotes an increase in steel magnetic induction which is important for turbogenerator rotors, was added to melt E with the aim of studying its effect on mechanical properties. Studies were performed on specimens 70 70 400 mm

I. A. Borisov; A. M. Shkatova; S. B. Vikhriev

1989-01-01

213

Effect of superrapid crystallization on the structure and properties of maraging steels  

SciTech Connect

Results are presented for a study of the features of the structure and properties of industrial maraging steel 01N17K12M5T prepared with superrapid crystallization of the melt. It is shown that superrapid crystallization of melts for maraging steels has a considerable effect on the nature of their phase transformation, structures, and properties. Depending on solidification rate and subsequent cooling it is possible to form in the steel, structures of the following types: entirely martensitic; entirely ferritic; a mixture of martensitic and austenitic components.

Chernysheva, T.A.; Lyul'kina, T.V.; Kalita, V.I.; Kobylkin, A.N.; Revyakina, O.K.

1988-07-01

214

Atomic force microscopy of induction- and furnace-heating-tempered prestressed steels with different delayed fracture properties  

Microsoft Academic Search

Quantitative microstructure analyses by atomic force microscope and delayed fracture tests were performed for two types of prestressed steel with a tensile strength of 1470 MPa; an induction-heated-tempered specimen, and a furnace-heated-tempered specimen. Size distributions of cementite particles were measured to characterize the relationship between microstructures and delayed fracture properties.

M Hayakawa; S Matsuoka; K Tsuzaki; H Hanada; M Sugisaki

2002-01-01

215

Helium effects on creep properties of Fe-14CrWTi ODS steel at 650 C  

NASA Astrophysics Data System (ADS)

In the present paper, the effects of helium on creep properties of Fe-14CrWTi ODS steel were studied by in-beam and post He-implantation creep tests. In-situ creep was performed in an in-beam creep device under uniaxial tensile stresses from 350 to 370 MPa during homogeneous helium implantation. Helium ions of energies varying from 0 to 25 MeV were implanted at a rate of 6 10-3 appm/s (corresponding to a displacement dose rate of 1.5 10-6 dpa/s). The average temperature was controlled to 650 C within 2 C. In addition, post He-implantation creep tests were conducted at 650 C as well. Subsequently, fracture surfaces and helium bubble evolution were studied in detail by SEM and TEM observations, respectively. Preliminary creep results show that helium slightly shortens the creep life time of ODS steel at 650 C. Fracture surfaces of reference as well as implanted specimens, show areas with various grades of deformation. Areas of highest deformation can be interpreted as necking, while areas of low deformation show in helium implanted specimens a more granular structure. The results are discussed in terms of possible embrittlement of ODS steels by helium.

Chen, J.; Jung, P.; Rebac, T.; Duval, F.; Sauvage, T.; de Carlan, Y.; Barthe, M. F.

2014-10-01

216

Measurement of the magnetic properties of P9 and T22 steel taken from service in power station  

NASA Astrophysics Data System (ADS)

With the UK's aging power generation network, life-extension of steel plant components is a critical issue. However, in order to evaluate the likelihood of component failure, techniques must be developed to properly assess the level of degradation in power station steels. Electromagnetic inspection has the potential to quantify the level of degradation through in-situ measurements at elevated temperatures. This paper reports the results of tests carried out on thermally treated P9 and T22 steel samples with different microstructural states using major and minor B-H loop measurements and magnetic Barkhausen noise measurements. The results show that by careful selection of minor loop parameters, specific to the material under inspection and the material change under consideration, correlations can established between EM properties and material properties such as Vickers hardness. These results will be used as a basis for the further development of a fully field deployable device.

Wilson, J. W.; Karimian, N.; Liu, J.; Yin, W.; Davis, C. L.; Peyton, A. J.

2014-06-01

217

Creep-fatigue interaction and related structure property correlations of EUROFER97 steel at 550 C by decoupling creep and fatigue load  

NASA Astrophysics Data System (ADS)

Mechanical tests have been performed at 550 C under vacuum on the ferritic-martensitic steel EUROFER97. These experiments included fatigue tests, creep tests and combined creep-fatigue tests. The latter showed significant cyclic softening in the fatigue stage and a remarkable break-down of creep strength in the creep stage. The cyclic softening behaviour was almost identical for all tests and therefore insensitive to the different strain amplitudes. SEM of the specimen's fracture surfaces and free surfaces revealed that networks of coagulated surface cracks formed during creep-fatigue were not failure relevant. TEM imaging displayed a drastic drop in dislocation density, and a considerable formation of precipitates and subgrain-structures in all tests. Pure fatigue led to the strongest reduction of dislocation density, whereas creep-fatigue induced the most pronounced formation of precipitates. Obviously, the internal softening due to prior cycling led to accelerated creep. Hence, a modified damage model for creep-fatigue load cases was proposed.

Vorpahl, C.; Mslang, A.; Rieth, M.

2011-10-01

218

Microstructure and Mechanical Properties of 316L Stainless Steel Filling Friction Stir-Welded Joints  

NASA Astrophysics Data System (ADS)

Keyhole left at 316L stainless steel friction stir welding/friction stir processing seam was repaired by filling friction stir welding (FFSW). Both metallurgical and mechanical bonding characteristics were obtained by the combined plastic deformation and flow between the consumable filling tool and the wall of the keyhole. Two ways based on the original conical and modified spherical keyholes, together with corresponding filling tools and process parameters were investigated. Microstructure and mechanical properties of 316L stainless steel FFSW joints were evaluated. The results showed that void defects existed at the bottom of the refilled original conical keyhole, while excellent bonding interface was obtained on the refilled modified spherical keyhole. The FFSW joint with defect-free interface obtained on the modified spherical keyhole fractured at the base metal side during the tensile test due to microstructural refinement and hardness increase in the refilled keyhole. Moreover, no ? phase but few Cr carbides were formed in the refilled zone, which would not result in obvious corrosion resistance degradation of 316L stainless steel.

Zhou, L.; Nakata, K.; Tsumura, T.; Fujii, H.; Ikeuchi, K.; Michishita, Y.; Fujiya, Y.; Morimoto, M.

2014-10-01

219

Studies of Evaluation of Hydrogen Embrittlement Property of High-Strength Steels with Consideration of the Effect of Atmospheric Corrosion  

NASA Astrophysics Data System (ADS)

Hydrogen embrittlement of high-strength steels was investigated by using slow strain rate test (SSRT) of circumferentially notched round bar specimens after hydrogen precharging. On top of that, cyclic corrosion tests (CCT) and outdoor exposure tests were conducted prior to SSRT to take into account the effect of hydrogen uptake under atmospheric corrosion for the evaluation of the susceptibility of high-strength steels. Our studies of hydrogen embrittle properties of high-strength steels with 1100 to 1500 MPa of tensile strength and a prototype ultrahigh-strength steel with 1760 MPa containing hydrogen traps using those methods are reviewed in this article. A power law relationship between notch tensile strength of hydrogen-precharged specimens and diffusible hydrogen content has been found. It has also been found that the local stress and the local hydrogen concentration are controlling factors of fracture. The results obtained by using SSRT after CCT and outdoor exposure test were in good agreement with the hydrogen embrittlement fracture property obtained by means of long-term exposure tests of bolts made of the high-strength steels.

Akiyama, Eiji; Wang, Maoqiu; Li, Songjie; Zhang, Zuogui; Kimura, Yuuji; Uno, Nobuyoshi; Tsuzaki, Kaneaki

2013-03-01

220

LITERATURE SURVEY OF GASEOUS HYDROGEN EFFECTS ON THE MECHANICAL PROPERTIES OF CARBON AND LOW ALLOY STEELS  

SciTech Connect

Literature survey has been performed for a compendium of mechanical properties of carbon and low alloy steels following hydrogen exposure. The property sets include yield strength, ultimate tensile strength, uniform elongation, reduction of area, threshold stress intensity factor, fracture toughness, and fatigue crack growth. These properties are drawn from literature sources under a variety of test methods and conditions. However, the collection of literature data is by no means complete, but the diversity of data and dependency of results in test method is sufficient to warrant a design and implementation of a thorough test program. The program would be needed to enable a defensible demonstration of structural integrity of a pressurized hydrogen system. It is essential that the environmental variables be well-defined (e.g., the applicable hydrogen gas pressure range and the test strain rate) and the specimen preparation be realistically consistent (such as the techniques to charge hydrogen and to maintain the hydrogen concentration in the specimens).

Lam, P; Robert Sindelar, R; Thad Adams, T

2007-04-18

221

LITERATURE SURVEY OF GASEOUS HYDROGEN EFFECTS ON THE MECHANICAL PROPERTIES OF CARBON AND LOW ALLOY STEELS  

SciTech Connect

Literature survey has been performed for a compendium of mechanical properties of carbon and low alloy steels following hydrogen exposure. The property sets include yield strength, ultimate tensile strength, uniform elongation, reduction of area, threshold stress intensity factor, fracture toughness, and fatigue crack growth. These properties are drawn from literature sources under a variety of test methods and conditions. However, the collection of literature data is by no means complete, but the diversity of data and dependency of results in test method is sufficient to warrant a design and implementation of a thorough test program. The program would be needed to enable a defensible demonstration of structural integrity of a pressurized hydrogen system. It is essential that the environmental variables be well-defined (e.g., the applicable hydrogen gas pressure range and the test strain rate) and the specimen preparation be realistically consistent (such as the techniques to charge hydrogen and to maintain the hydrogen concentration in the specimens).

Lam, P; Andrew Duncan, A; Robert Sindelar, R; Thad Adams, T

2009-04-27

222

Characterization of microstructures and mechanical properties of Inconel 617/310 stainless steel dissimilar welds  

SciTech Connect

The microstructure and mechanical properties of Inconel 617/310 austenitic stainless steel dissimilar welds were investigated in this work. Three types of filler materials, Inconel 617, Inconel 82 and 310 austenitic stainless steels were used to obtain dissimilar joint using the gas tungsten arc welding process. Microstructural observations showed that there was no evidence of any possible cracking in the weldments achieved by the nickel-base filler materials. The welds produced by 617 and 310 filler materials displayed the highest and the lowest ultimate tensile strength and total elongation, respectively. The impact test results indicated that all specimens exhibited ductile fracture. Among the fillers, Inconel 617 exhibited superlative fracture toughness (205 J). The mechanical properties of the Inconel 617 filler material were much better than those of other fillers. - Research Highlights: {yields} A fine dendritic structure was seen for the Inconel 617 weld metal. {yields} A number of cracks were initiated when the 310 SS filler metal was used. {yields} All welded samples showed ductile fracture. {yields} The Inconel 617 filler material presents the optimum mechanical properties.

Shah Hosseini, H., E-mail: h.shahhosseini@ma.iut.ac.ir; Shamanian, M.; Kermanpur, A.

2011-04-15

223

Influence of heat treatment on mechanical properties of 300M Steel  

NASA Technical Reports Server (NTRS)

The plane strain fracture toughness and tensile strength response of 300M Steel to a wide variety of austenitizing and tempering temperatures were investigated. The results make it possible for one to select heat treatments which provide an optimum combination of strength and toughness for a variety of structural applications. In particular, improvements in toughness on the order of 20% were found possible with no loss in tensile properties by increasing the austenitizing temperature from the currently employed 1144 K to 1255 K or higher, and this change in heat treatment therefore appears worthy of general implementation.

Youngblood, J. L.; Raghavan, M. R.

1975-01-01

224

Effect of Impurity Tin on the Creep Properties of a P91 Heat-Resistant Steel  

NASA Astrophysics Data System (ADS)

The creep properties of P91 steel specimens undoped and doped with 0.058 wt pct tin, which was normalized from 1328 K (1055 C) and tempered at 1033 K (760 C), were examined under different engineering stresses (150 to 210 MPa) and temperatures [873 K to 923 K (600 C to 650 C)]. The creep behavior followed the temperature-compensated power law and Monkman-Grant equations. In the temperature-compensated power law equation, the apparent activation energy and stress exponent for creep were approximately 541 kJ/mol and 12 for the undoped steel and 527 kJ/mol and 11 for the Sn-doped one, respectively. In the Monkman-Grant relation, the values of constants m and C were around 1.062 and 0.0672 for the undoped steel, and 1.012 and 0.0650 for the Sn-doped one, respectively. The 100 MPa stress creep lifetime at 873 K (600 C) was estimated as 100641 hours for the undoped steel and 35290 hours for the Sn-doped steel, respectively. These indicated that Sn substantially deteriorated the creep properties of the steel. It was found that grain or subgrain boundary segregation of Sn could promote the nucleation of cavities or microcracks, thereby leading to the deterioration of the steel creep properties.

Song, S.-H.; Xu, Y.-W.; Yang, H.-F.

2014-09-01

225

Morphology and properties of hot dip ZnMg and ZnMgAl alloy coatings on steel sheet  

Microsoft Academic Search

Hot dip coating on low carbon steel sheet samples by binary ZnMg alloy with low and high Mg and a ternary ZnMgAl alloy, and their characterization and property evaluation have been described in this article. A good quality coating with respect to surface quality, coating structure and anti-corrosion properties was achieved at a lower bath temperature than in conventional galvanizing.

Monojit Dutta; Arup Kumar Halder; Shiv Brat Singh

2010-01-01

226

Microstructures and mechanical properties of injection molded 17-4PH stainless steel powder with nickel boride additions  

Microsoft Academic Search

This paper describes the sintering of an injection molded 17-4 PH stainless steel with additions of nickel boride (NiB), with the aim of producing high mechanical properties. Boron is evaluated as the best sintering enhancing element in terms of densifying the iron-based materials by formation the liquid phase. Sintered density and mechanical properties were increased with the increased amount of

H. . Glsoy; S. Salman

2005-01-01

227

Joining of aluminum alloy to steel by friction stir welding  

Microsoft Academic Search

The authors tried to butt-weld an aluminum alloy plate to a mild steel plate by friction stir welding, and investigated the effects of a pin rotation speed, the position for the pin axis to be inserted on the tensile strength and the microstructure of the joint. The behavior of the oxide film on the faying surface of the steel during

Takehiko Watanabe; Hirofumi Takayama; Atsushi Yanagisawa

2006-01-01

228

Phosphorus Removal in Sewage by Mixed Steel Slag Fillings  

Microsoft Academic Search

The purpose of the paper is purifying phosphorus by column experiment and researching phosphorus removal theory of substrates including steel slag, natural sand and limestone. The winch is composed of the following main parts: experiment method and procedure, results and discussion and conclusion. The results indicated: Pure steel slag is not suitable as filling in wastewater land treating. Mixing natural

Huang Ling; Su Yongqiang

2009-01-01

229

Structure and mechanical properties of the 03Kh14GNF steel after deformation and annealing  

NASA Astrophysics Data System (ADS)

It has been shown that the annealing of cold-worked 03Kh14GNF steel is accompanied by several strengthening and softening processes that take place in different temperature intervals. Therefore, the temperature dependence of its hardness has a complicated form; i.e., it contains several maxima and minima. The following processes should be noted: recovery and recrystallization of ? ferrite, precipitation of M 2(CN) carbonitrides and M 23C6 carbides from the ? martensite, their dissolution in the ? phase, the formation of austenite with different stability, polygonization of the ? martensite, etc. Tempering for 30 h can produce the level of mechanical properties required according to technical specifications for two processing regimes. These regimes are the annealing at 680C and at 600C, but in the second case the high plasticity is probably caused by the formation of a highly stable austenite that is retained down to room temperature. However, the degree of plasticity of this ? phase at room and lower temperatures is unknown. After annealing at 660C, the steel does not achieve the level of ultimate strength of 480 N/mm2, which is required by the technical specifications. However, since the relative elongation of 35% exceeds the required magnitude, the required level of mechanical properties can apparently be produced by a decrease in the duration of annealing to 20-25 h.

Shaburov, D. V.; Valitov, V. G.; Mirzaev, D. A.; Yakovleva, I. L.; Kirpichnikov, M. S.; Vetoshkina, T. Yu.

2009-04-01

230

An internal friction peak caused by hydrogen in maraging steel  

SciTech Connect

Internal friction in hydrogen-charged iron and steel has so far been studied by a large number of investigators. For pure iron, a well-defined peak of internal friction has been observed under the cold-worked and hydrogen-charged conditions. This is called the hydrogen cold-work peak, or the Snoek-Koester relaxation, which originates from the hydrogen-dislocation interaction. In the present study, a high-strength maraging steel (Fe-18Ni-9Co-5Mo) was chosen as another high-alloy steel which is known to be very susceptible to hydrogen embrittlement. The purpose of this paper is to show a new internal friction peak caused by hydrogen in the maraging steel and to compare it with those found in stainless steels which have so far been studied as typical engineering high-alloy materials.

Usui, Makoto [Aichi Steel Works, Ltd., Tokai (Japan)] [Aichi Steel Works, Ltd., Tokai (Japan); Asano, Shigeru [Nagoya Inst. of Tech. (Japan)] [Nagoya Inst. of Tech. (Japan)

1996-01-01

231

Effects of Manufacturing Processes and In-Service Temperature Variations on the Properties of TRIP Steels  

SciTech Connect

This paper examines key aspects of the manufacturing process that Transformation Induced Plasticity (TRIP) steels would be exposed to, and systematically evaluate how the forming and thermal histories affect final strength and ductility of the material. The paper evaluates in-service temperature variations, such as under hood and hot/cold cyclic conditions, to determine whether these conditions influence final strength, ductility and energy absorption characteristics of several available TRIP steel grades. As part of the manufacturing thermal environment evaluations, stamping process thermal histories are included in the studies. As part of the in-service conditions, different pre-straining levels are also included. Materials from four steel suppliers world wide are examined. The material properties are established over a full range of expected thermal histories and selected loading modes. Establishing these relationships will allow OEM designers to select TRIP steels for proper vehicle applications, and to specify manufacturing process conditions that yield reliable final material property levels.

Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

2007-04-30

232

Microstructure and mechanical properties of friction stir processed ODS ferritic steels  

NASA Astrophysics Data System (ADS)

Oxide dispersion strengthened (ODS) steels are considered to be one of the candidate structural materials for advanced blanket systems because of its excellent properties in fusion environments. For more applications of the ODS steels to fusion systems with a huge and complex structure, development of joining technologies is a key issue to be solved. To reserve nano-oxide particles in the matrix homogeneously, the friction stir welding (FSW) is a suitable way to get good welding characteristics as a solid-state processing technique. In this research, effects of friction stir processing (FSP) on microstructure and mechanical properties of a ODS steel were studied to apply FSW process to ODS steels. The microstructure of FSPed ODS steel consists of stirred zone (SZ) and base metal (BM), as reported for other ferritic steels. Although equiaxed grain coarsening occurred through dynamic recrystallization during FSP, the nano-oxide particles in SZ showed fewer change in the size distribution. This resulted that FSP is effective to suppress the anisotropy and minimize the change of nano-oxide particles dispersion morphologies of ODS steel.

Noh, Sanghoon; Kasada, Ryuta; Kimura, Akihiko; Park, Seung Hwan C.; Hirano, Satoshi

2011-10-01

233

Experimental and analytical analysis of the high-temperature mechanical properties of steel under continuous casting conditions  

Microsoft Academic Search

The modelling of thermo-mechanical aspects of the continuous casting of steel demands knowledge of the constitutive material equations which describe the complex relationships between stress, strain and time at temperatures up to the melting point. The mechanical properties of steel at higher temperatures depend not only on the composition and temperature of the steel, but also on the microstructure, which,

R. Pierer; C. Bernhard; C. Chimani

234

Effect of Ti addition on the microstructure and mechanical properties of a cast Fe-Ni-Mo-Mn maraging steel  

NASA Astrophysics Data System (ADS)

To study the effect of Ti on the age hardening behavior of Fe-Ni-Mn maraging steels, a Fe-Ni-Mo-Mn steel was alloyed with Ti then mechanical properties and aging behavior of two cast steels were investigated. In this regard, two heats of nominal compositions of Fe-10Ni-6Mo-3Mn and Fe-lONi-6Mo-3Mn-0. 7Ti were induction melted in air and vacuum respectively and cast in iron mold. After homogenizing at 1473K for 21.6ks and water quenching, solution annealing was performed at 1223K for 3.6ks followed by air cooling. Age hardening behavior at 773Kin the range of 0.36-172. 8 ks was determined. Tensile properties and Charpy impact toughness were measured in the solution annealed and peak-aged conditions. Fractographic features were studied by scanning electron microscope equipped with EDX microanalyses. Tensile properties of the alloys in the peakaged condition were in the range of grade 200 standard maraging steel. It has been found that Ti addition resulted in increasing of hardness and strength in aged condition and decreasing of Charpy impact toughness in both solution annealed and aged conditions. Ti addition also changes type and morphology of inclusions and fracture mechanism from semi-ductile intergranular mode to semi-ductile transgranular one.

Nejad, S. Hossein; Nili Ahmadabadi, M.

2003-10-01

235

Magnetic properties of Cr-Mn austenitic stainless steels  

NASA Astrophysics Data System (ADS)

The magnetic susceptibility x of three Cr-Mn austenitic stainless steels was measured as a function of temperature in the range 5-400 K. All specimens showed a characteristic susceptibility maximum. The temperature of the maximum and especially the curve shape depend strongly on specimen composition and metallurgical conditions (as-quenched, deformed). Because no significant field dependence appeared, the susceptibility maximum was identified as the antiferromagnetic Nel temperature. x;( T) measurements above TN were fitted to a modified Curie-Weiss equation. Comparison between measurements and generalized-molecular-field-theory predictions allowed us to identify the magnetic structure as that of a first-type antiferromagnet with fcc crystal structure. The atomic magnetic moment and the molecular-field coefficients depend strongly not only on composition, but also on metallurgical prehistory, that is, on the degree of the applied mechanical deformation and heat treatment. Mainly, manganese affected the antiferromagnetic interactions, while chromium affected the ferromagnetic. Mn and Fe contributed the most to the effective atomic moment. Measurements on mechanically deformed specimens show a structure sensitivity of the molecular-field constants. This could be interpreted consistently in terms of lattice-parameter changes. The apparent structure sensitivity of the effective atomic moment can be attributed to changes in matrix composition caused by precipitation.

Fldeki, Maria; Ledbetter, Hassel; Uggowitzer, Peter

1992-04-01

236

Study of TRIP-Aided Bainitic Ferritic Steels Produced by Hot Press Forming  

NASA Astrophysics Data System (ADS)

A study is reported to produce high strength ductile steels by controlled cooling following hot press forming, instead of quenching, as is practiced in the traditional press hardened steels. Heat treatments of several specially designed low carbon steels were carried out by interrupting the fast cooling from the austenization temperature at temperatures between T 0 and Ms and then cooling in controlled rates to room temperature. The effect of the interrupt temperature and the cooling rate afterward on the microstructures and tensile properties was studied. The microstructures were characterized using dilatometry, optical microscopy, X-ray diffraction, and TEM. A multi-phase microstructure including bainite, martensite, and retained austenite was obtained in the simulated hot press forming process. Volume fraction bainite was found to increase with an increase in interrupt temperature and a decrease in cooling rate. Structure-property correlations of the studied steels heat treated at different conditions were developed. Improved tensile properties were obtained by controlling the interrupt temperature and cooling rate which produced an optimum bainite content of 60 to 75 pct and retained austenite. Unfortunately, the bainite in the simulated samples was not completely carbide free even though the steels contained about 1.6 wt pct of Si.

Chen, Shangping; Rana, Radhakanta; Lahaije, Chris

2014-04-01

237

Service properties of Cr-Mo-V steels in different structural conditions  

SciTech Connect

The authors study the influence on heat-treatment cycles on the service properties of 12Kh1MF steel. Variations in heat analysis within specification limits do not have a marked influence on the stress-rupture strength of 15Kh1M1F steel in the investigated temperature-time interval but do significantly influence its long-term plasticity. The higher the stress-rupture strength of the material, the stronger this influence.

Mints, I.I.; Shul'gina, N.G.; Smirnova, A.P.

1986-05-01

238

Corrosion properties of active screen plasma nitrided 316 austenitic stainless steel  

Microsoft Academic Search

AISI 316 austenitic stainless steel has been plasma nitrided using the active screen plasma nitriding (ASPN) technique. Corrosion properties of the untreated and AS plasma nitrided 316 steel have been evaluated using various techniques, including qualitative evaluation after etching in 50%HCl+25%HNO3+25%H2O, weight loss measurement after immersion in 10% HCl, and anodic polarisation tests in 3.5% NaCl solution. The results showed

C. X Li; T Bell

2004-01-01

239

Structure and properties of the gradient tool materials of unalloyed steel matrix reinforced with HS6-5-2 high-speed steel  

Microsoft Academic Search

Purpose: The goal of this work is to obtain the gradient materials based on the non-alloyed steel reinforced high- speed steel using the pressureless formed method. Design\\/methodology\\/approach: The non-alloyed steel was fabricated by mixing iron powders with graphite. The unalloyed steel contains 0.5% carbon. The pressureless powder forming was used for manufacturing the materials. Findings: It was found out, basing

L. A. Dobrzaski; A. Kloc-Ptaszna; G. Matul; J. M. Torralba

240

Study of Ph Curves on Nanomechanical Properties of Steel Fiber Reinforced Mortar  

Microsoft Academic Search

Steel fiber reinforced mortars with w\\/b 0.3 and 0.5 with and without 10% silica fume by cement weight were investigated using\\u000a a Hysitron Triboindenter with Berkovich tip, indenting in the interfacial transition zone (ITZ) between steel fiber and matrix, and also on the steel\\u000a fiber and aggregate using 5mN maximum force to obtain P-h (Load-Displacement) curves for elastic modulus and

S. F. Lee; J. Y. He; X. H. Wang; Z. L. Zhang; S. Jacobsen

241

Effect of rolling at sub-zero temperatures on mechanical properties of austenitic steels  

Microsoft Academic Search

1.Cold rolling of austenitic steels to increase their tensile characteristics is most effective at sub-zero temperatures. Tensile and yield strengths are increased by up to 2030% over those after rolling at ordinary temperature, without impairing the ductility.2.At low temperatures, austenitic steels have high reduction of area and elongation, irrespective of the previous strain hardening at ordinary temperatures.3.Austenitic steel components for

N. N. Lyulicheva; N. V. Pisareva

1959-01-01

242

Stress corrosion cracking properties of 15-5PH steel  

NASA Technical Reports Server (NTRS)

Unexpected occurrence of failures, due to stress corrosion cracking (SCC) of structural components, indicate a need for improved characterization of materials and more advanced analytical procedures for reliably predicting structures performance. Accordingly, the purpose of this study was to determine the stress corrosion susceptibility of 15-5PH steel over a wide range of applied strain rates in a highly corrosive environment. The selected environment for this investigation was a highly acidified sodium chloride (NaCl) aqueous solution. The selected alloy for the study was a 15-5PH steel in the H900 condition. The slow strain rate technique was selected to test the metals specimens.

Rosa, Ferdinand

1993-01-01

243

Effect of annealing prior to cold rolling on magnetic and mechanical properties of low carbon non-oriented electrical steels  

NASA Astrophysics Data System (ADS)

The effects of annealing prior to cold rolling on the microstructure, magnetic and mechanical properties of low-C grain non-oriented (GNO) electrical steels have been investigated. The grain structure of hot-rolled electrical steel strips is modified by annealing at temperatures between 700 and 1050 C. Annealing at temperatures less than the ferrite to austenite+ferrite transformation temperature on heating (Ac 1) causes a marginal effect on the grain size. However, annealing in the intercritical region at temperatures between Ac 1 and Ac 3 (the ferrite+austenite to austenite transformation temperature on heating) causes rapid decarburization and development of large columnar ferrite grains free of carbide particles. This microstructure leads, after cold rolling and a fast annealing treatment, to carbide free, large ferrite grain microstructures with magnetic and mechanical properties superior to those observed typically in the same steel in the industrially fully processed condition. These results are attributed to the increment in grain size and to the {1 0 0} fiber texture developed during the final annealing at temperatures up to 850 C. Annealing at higher temperatures, T>Ac 3, results in a strong {1 1 1} fiber texture and an increase of the quantity of second phase particles present in the microstructure, which lead to a negative effect on the final properties. The results suggest that annealing prior to cold rolling offers an attractive alternative processing route for the manufacture of fully processed low C GNO electrical steels strips.

Gutirrez-Castaeda, E. J.; Salinas-Rodrguez, A.

2011-10-01

244

Difference between helium retention properties in 316L and 304 stainless steels  

NASA Astrophysics Data System (ADS)

The difference between helium behavior in type 316L and 304 stainless steels at high temperature was examined. Thermal desorption experiments were performed to obtain fundamental knowledge on the retention properties of helium atoms and in situ TEM observation was also carried out to examine the related dynamic behavior of helium bubbles. The desorption properties indicated that SUS316L has strong retention up to high temperatures. In SUS316L, a large desorption peak was present at temperatures above 1200 K, whereas most of the retained helium was desorbed at comparatively low temperatures in SUS304. In situ TEM observation consistently showed rather lower mobility of bubbles in SUS316L compared with SUS304. The suppression of bubble motion could be caused by Mo atoms, the additive in SUS316L.

Miyamoto, Mitsutaka; Ono, Kotaro; Mori, Yusuke; Shitabou, Daigo

2009-04-01

245

Physical and mechanical properties of cast 17-4 PH stainless steel  

SciTech Connect

The physical and mechanical properties of an overaged 17-4 PH stainless steel casting have been examined. The tensile and compressive properties of cast 17-4 PH are only influenced to a slight degree by changing test temperature and strain rate. However, both the Charpy impact energy and dynamic fracture toughness exhibit a tough-to-brittle transition with decreasing temperature - this transition being related to a change in fracture mode from ductile, dimple to cleavage-like. Finally, although the overaged 17-4 PH casting had a relatively low room temperature Charpy impact energy when compared to wrought 17-4 PH, its fracture toughness was at least comparable to that of wrought 17-4 PH. This observation suggests that prior correlations between Charpy impact energies and fracture toughness, as derived from wrought materials, must be approached with caution when applied to cast alloys.

Rack, H. J.

1981-02-01

246

Oxidation resistance in LBE and air and tensile properties of ODS ferritic steels containing Al/Zr elements  

NASA Astrophysics Data System (ADS)

The effects of Al and Zr addition on improvement of oxidation resistance in lead-bismuth eutectic (LBE) and in air as well as the tensile properties were investigated for the oxide dispersion strengthened (ODS) steels. The 16Cr-4Al-0.8Zr-ODS steel samples were fabricated by a sol-gel method combining with spark plasma sintering technique. The tests in LBE at 600 C for 1000 h indicate the good oxidation resistance comparing with the specimens without Zr/Al elements. The samples also exhibit superior oxidation resistance in air due to formation of dense and continuous aluminum oxide film. Minor Zr addition prevents the Al element induced coarsening of the oxide particles in ODS steels and significantly improves the ultimate tensile stress and total elongation of the samples.

Gao, R.; Xia, L. L.; Zhang, T.; Wang, X. P.; Fang, Q. F.; Liu, C. S.

2014-12-01

247

Microstructure and mechanical properties in TIG welding of CLAM steel  

Microsoft Academic Search

Tungsten insert gas (TIG) welding on China low activation martensitic (CLAM) steel under identical conditions was performed. Microhardness test, tensile test, Charpy impact test and microstructure measurements were carried out on TIG welded joints after post weld heat-treatment. Hardening at WM and softening in HAZ is detected in the TIG weld joint. Microhardness in WM decreased when the temperature of

Qiang Zhu; Yu-cheng Lei; Xi-zhang Chen; Wen-jie Ren; Xin Ju; Yi-min Ye

2011-01-01

248

MODELING STRESS DEPENDENCE OF MAGNETIC PROPERTIES FOR NDE OF STEELS  

Microsoft Academic Search

Application of the Sablik-Jiles magnetomechanical theory to various NDE techniques for measuring stress in steels is reviewed. Among the techniques discussed are (1) differential anhysteretic susceptibility, (2) higher order harmonic amplitudes of the hysteretic magnetic flux density, (3) magabsorption, which involves measurement of the rf impedance of a coil coupled to a ferromagnetic material, and (4) Barkhausen measurements.

M. J. SABLIK

1989-01-01

249

Effect of Partial Replacement of Si with Al on the Microstructures and Mechanical Properties of 1000 MPa TRIP Steels  

NASA Astrophysics Data System (ADS)

Two newly synthesized C-Mn-Si-Mo-Nb transformation-induced plasticity (TRIP) steels with and without Al addition were designed in order to achieve significant improvements in the mechanical properties. The effect of substitution of Si by Al on tensile properties and the microstructure of cold-rolled C-Mn-Si TRIP steel was investigated under different heat treatments. It was shown that a complex ultrafine microstructure composed of different phases was formed and two types of morphology for ferrite were detected (equiaxial and polygonal). The distribution of alloying elements was observed by using electron probe microanalysis. It was clear that C was concentrated in the retained austenite (RA) and small M/A (austenite/martensite) islands. The Al addition facilitated the formation of polygonal ferrite and increased the stability of the RA. The strain-hardening behavior was studied in detail. All the investigated specimens showed a very high strain-hardening exponent (instantaneous n) but their strain dependence was different. For the C-Mn-Si-Mo-Nb TRIP steel, the maximum n value was achieved when the strain was only about 0.04, while the n value of the Al substituted TRIP steel increased gradually until strains in the range of 0.07-0.10 were reached and the maximum value was achieved. As a result, the elongations of the steel with Al addition increased considerably without obvious deterioration of strength. It was the first time to find microtwinned martensite located between ferrite and bainitic ferrite after tensile deformation in the low alloy TRIP steel with Al.

Wang, Chao; Ding, Hua; Zhang, Jun; Di, Huafang

2014-11-01

250

The protective properties of thin alumina films deposited by metal organic chemical vapour deposition against high-temperature corrosion of stainless steels  

Microsoft Academic Search

Coatings of Al2O3 were deposited on Incoloy 800H and AISI 304 by means of metal organic chemical vapour deposition. Diffusion limitation was the rate-determining step above 420 C. Below this temperature, the activation energy of the reaction appeared to be 30 kJ mol?1. Coating with Al2O3 increases the sulphidation resistance by at least 410 times. The sulphidation resistance is influenced

R. W. J. Morssinkhof; T. Fransen; M. M. D. Heusinkveld; P. J. Gellings

1989-01-01

251

Effect of boron addition on injection molded 316L stainless steel: mechanical, corrosion properties and in vitro bioactivity.  

PubMed

The research was investigated the effect of boron additions on sintering characteristics, mechanical, corrosion properties and biocompatibility of injection molded austenitic grade 316L stainless steel. Addition of boron is promoted to get high density of sintered 316L stainless steels. The amount of boron plays a role in determining the sintered microstructure and all properties. In this study, 316L stainless steel powders have been used with the elemental NiB powders. A feedstock containing 62.5 wt% powders loading was molded at different injection molded temperature. The binders were completely removed from molded components by solvent and thermal debinding at different temperature. The debinded samples were sintered at different temperature for 60 min. Mechanical property, microstructural characterization and electrochemical property of the sintered samples were performed using tensile testing, hardness, optical, scanning electron microscopy and electrochemical corrosion experiments. Sintered samples were immersed in a simulated body fluid (SBF) with elemental concentrations that were comparable to those of human blood plasma for a total period of 15 days. Both materials were implanted in fibroblast culture for biocompatibility evaluations were carried out. Results of study showed that sintered 316L and 316L with NiB addition samples exhibited high mechanical and corrosion properties in a physiological environment. Especially, 316L with NiB addition can be used in some bioapplications. PMID:23114463

Bayraktaroglu, Esra; Gulsoy, H Ozkan; Gulsoy, Nagihan; Er, Ozay; Kilic, Hasan

2012-01-01

252

High Temperature Straining Behaviour Of High FeSi Electrical Steel By Torsion Tests  

Microsoft Academic Search

Steel with an increased Si-content has better magnetic properties in electrical applications in terms of high electrical resistivity, reduced energy losses and low magnetostriction. Nevertheless, the oxygen affinity of this element at high working temperatures and the poor ductility observed at room temperature caused by order structures make the thermomechanical processing of these alloys rather difficult. Since these materials do

P. R. Calvillo; N. Lasa Garca; Y. Houbaert

2007-01-01

253

Surface enhancement of cold work tool steels by friction stir processing with a pinless tool  

NASA Astrophysics Data System (ADS)

The microstructure and mechanical properties of enhanced tool steel (AISI D2) surfaces produced using a friction stir welding (FSW) related procedure, called friction stir processing (FSP), are analysed in this work. The surface of the tool steel samples was processed using a WC-Co pinless tool and varying processing conditions. Microstructural analysis revealed that meanwhile the original substrate structure consisted of a heterogeneous distribution of coarse carbides in a ferritic matrix, the transformed surfaces consisted of very small carbides, homogenously distributed in a ferrite- bainite- martensite matrix. The morphology of the surfaces, as well as its mechanical properties, evaluated by hardness and tensile testing, were found to vary with increasing tool rotation speed. Surface hardness was drastically increased, relative to the initial hardness of bulk steel. This was attributed to ferrite and carbide refinement, as well as to martensite formation during solid state processing. At the highest rotation rates, tool sliding during processing deeply compromised the characteristics of the processed surfaces.

Costa, M. I.; Verdera, D.; Vieira, M. T.; Rodrigues, D. M.

2014-03-01

254

The Effects of Martensite Content on the Mechanical Properties of Quenched and Tempered 0.2%C-Ni-Cr-Mo Steels  

Microsoft Academic Search

Three martensite contents (approximately 35, 50, and 100%) were obtained in a SAE8822 steel by altering the quenching media\\u000a and section size. Another variation in martensite content (approximately 80 versus 97%) was achieved by quenching a SAE8622\\u000a steel in the same section size. The impact toughness and fatigue properties were determined after tempering to various levels\\u000a of monotonic strength. Toughness

John M. Tartaglia

2010-01-01

255

Correlations between mechanical properties and cavitation erosion resistance for stainless steels with 12% Chromium and variable contents of Nickel  

NASA Astrophysics Data System (ADS)

The running time of hydraulic machineries in cavitation conditions, especially blades and runners, depend on both chemical composition and mechanical properties of the used steels. The researches of the present paper have as goal to obtain new materials with improved behavior and reduced costs. There are given cavitation erosion results upon eight cast steels with martensite as principal structural constituent. The chromium content was maintained constant at approximate 12% but the nickel content was largely modified. The change of chemical content resulted in various proportions of austenite, martensite and ferrite and also in different cavitation erosion behavior. From the eight tested steels four have greater carbon content (approximately 0.1%) and the other four less carbon content (approximate 0.036%). All steels were tested separately in two laboratory facilities: T1 with magnetostrictive nickel tube (vibration amplitude 94 ?m, vibration frequency 7000 3% Hz, specimen diameter 14 mm and generator power 500 W) and T2 is respecting the ASTM G32-2010 Standard (vibration amplitude 50?m, vibration frequency 20000 1% Hz, specimen diameter 15.8 mm and generator power 500 W). Analyzing the results it can be seen that the cavitation erosion is correlated with the mechanical properties in the way shown in 1960 by Hammitt and Garcia but is influenced by the structural constituents.

Bordeasu, I.; Popoviciu, M. O.; Mitelea, I.; Ghiban, B.; Ghiban, N.; Sava, M.; Duma, S. T.; Badarau, R.

2014-03-01

256

10. DETAIL, SOUTHEAST SPAN THROUGH CANAL, VIEW BLOCKED BY STEEL, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. DETAIL, SOUTHEAST SPAN THROUGH CANAL, VIEW BLOCKED BY STEEL, CLAD COUNTER WEIGHT, WATER SPAN RAISED OUT OF VIEW - Cape Cod Canal Lift Bridge, Spanning Cape Cod Canal, Buzzards Bay, Barnstable County, MA

257

Stainless-steel elbows formed by spin forging  

NASA Technical Reports Server (NTRS)

Large seamless austenitic stainless steel elbows are fabricated by spin forging /rotary shear forming/. A specially designed spin forging tool for mounting on a hydrospin machine has been built for this purpose.

1964-01-01

258

Machinability of a Stainless Steel by Electrochemical Discharge Microdrilling  

SciTech Connect

Due to the chemical elements included in their structure for ensuring an increased resistance to the environment action, the stainless steels are characterized by a low machinability when classical machining methods are applied. For this reason, sometimes non-traditional machining methods are applied, one of these being the electrochemical discharge machining. To obtain microholes and to evaluate the machinability by electrochemical discharge microdrilling, test pieces of stainless steel were used for experimental research. The electrolyte was an aqueous solution of sodium silicate with different densities. A complete factorial plan was designed to highlight the influence of some input variables on the sizes of the considered machinability indexes (electrode tool wear, material removal rate, depth of the machined hole). By mathematically processing of experimental data, empirical functions were established both for stainless steel and carbon steel. Graphical representations were used to obtain more suggestive vision concerning the influence exerted by the considered input variables on the size of the machinability indexes.

Coteata, Margareta; Pop, Nicolae; Slatineanu, Laurentiu ['Gheorghe Asachi' Technical University of Iasi, Department of Machine Manufacturing Technology, Blvd. D Mangeron 59A, 700050 Iasi (Romania); Schulze, Hans-Peter [Otto-von-Guericke-University Magdeburg, Institute of Fundamental Electrical Engineering and EMC Universitaetsplatz 2, D-39106 Magdeburg (Germany); Besliu, Irina [University 'Stefan cel Mare' of Suceava, Department of Technologies and Management, Str. Universitatii, 13, 720 229 Suceava (Romania)

2011-05-04

259

Anisotropic magnetic properties and domain structure in Fe-3%Si (110) steel sheet  

NASA Astrophysics Data System (ADS)

The understanding of the anisotropic magnetization mechanism in 3%Si steel is relevant to both the design of the electrotechnical applications of 3%Si steel and the fundamental materials science of soft magnetic materials. In the present study, the relation between the anisotropic magnetic properties and the magnetization curves of 3%Si-Fe (110) steel sheet for various directions of axial magnetization was studied taking into account the domain structure. The magnetic loss of the (110) steel sheet were measured in an applied field at an angle ? to the [001] axis. The angle ? was varied from 0 to 90, in steps of 15. In off-[001] directions, the magnetization resulted in a highly structured domain pattern and domain wall displacements, which could be related to the shape of the magnetization curves. The magnetization curves could be divided in four segments, with each segment related to a specific domain structure.

Shin, Sunmi; Schaefer, Rudolf; DeCooman, B. C.

2011-04-01

260

Magnetic Properties and Domain Structure of Non-oriented Electrical Steel Under Stress  

NASA Astrophysics Data System (ADS)

The influence of stresses on the magnetic properties of non-oriented electrical steels was studied. The dependence of iron loss on compressive stress was affected by grain size. The magnetic polarization J at high magnetic fields such as 5000A/m and 10000A/m increased by compressive stresses and decreased by tensile stresses in samples with low Si contents. Using Kerr-effect domain observation, it was found that the reduction in J caused by tensile stresses was attributable to residual striped domains. Magnetostriction measurements at high magnetic fields indicated that the increase in J under compressive stresses originated from the Villari-effect due to negative magnetostriction in low Si materials.

Senda, Kunihiro; Fujita, Akira; Honda, Atsuhito; Kuroki, Naoki; Yagi, Masaaki

261

Tribological properties of silicon nitride ceramics coated with DLC and DLC-Si against 316L stainless steel  

Microsoft Academic Search

Diamond-like carbon (DLC) is an adequate coating on a large variety of materials for tribological purposes, namely against iron alloys in automotive parts, bearings and forming tools. Herein, the tribological properties of DLC-stainless steel couples were assessed by unlubricated pin-on-disc experiments. Plasma enhanced chemical vapour deposition (PECVD) of DLC-Si or pure DLC coatings were performed, respectively, by conventional rf glow

J. R. Gomes; S CAMARGOJR; R. A. Simo; J. M. Carrapichano; C. A. Achete; R. F. Silva

2007-01-01

262

Hydrogen pumping by austenitic stainless steel  

NASA Astrophysics Data System (ADS)

In the present study, hydrogen sorption and desorption kinetics close to equilibrium were investigated in a pinched-off AISI 316 steel cell by a sensitive pressure-rise method. The pressure was monitored with a spinning rotor gauge (SRG) just before the pinch-off and after it for 6 months at two stabilized temperatures: 25 C and 55 C. The preprocessing of the cell (of uniform wall thickness 0.15 mm volume 125 cm3, and inner surface 460 cm2) consisted of baking at 200 C for 109 h with several evacuation cycles to ultrahigh vacuum (UHV). The quantity of released hydrogen during the bake-out procedure equaled the average concentration change ?C=2.81017 at. H cm-3. After the pinch-off intentionally done in the high vacuum range where hydrogen represented the residual atmosphere, surprisingly the hydrogen pressure slowly declined from the initial p(328 K)=3.710-4 mbar, with an initial rate dp/dt=-5.510-11 mbar/s and later attained a stable value, which could be termed the equilibrium. In similar reported experiments, where valving-off began in the UHV, the dp/dt was always positive and constant over several orders of magnitude in pressure. During 6 months of measurements, a sudden temperature jump from 25 C to 55 C or back was applied a few times to investigate the stability of the equilibrium or the impact on the pressure course. The most plausible explanation of the results is given along with discussion whether hydrogen permeated through the cell wall or if it was absorbed in the cell wall.

Zajec, Bojan; Nemani?, Vincenc

2005-03-01

263

Magnetic properties of Cr-Mn austenitic stainless steels  

Microsoft Academic Search

The magnetic susceptibility x of three Cr-Mn austenitic stainless steels was measured as a function of temperature in the range 5-400 K. All specimens showed a characteristic susceptibility maximum. The temperature of the maximum and especially the curve shape depend strongly on specimen composition and metallurgical conditions (as-quenched, deformed). Because no significant field dependence appeared, the susceptibility maximum was identified

Maria Fldeki; Hassel Ledbetter; Peter Uggowitzer

1992-01-01

264

Effects of Heat Treatment on Microstructure and Tensile Properties of a Fe-27Mn-12Al-0.8C Low-Density Steel  

NASA Astrophysics Data System (ADS)

A low-density duplex steel of Fe-27Mn-12Al-0.8C (density 6.53 g/cm3) was directly quenched to room temperature and ordering treated at 500C and 700C after solution treatment. The heat-treated microstructures and corresponding room-temperature tensile properties were investigated. The ? phase precipitated in austenite in all the cases such that its size became coarser with increasing ordering temperature. Ferrite of the as-quenched steel consisted of the B2 domains and disordered ferrite with uniformly distributed nanosized D03 particles. Ferrite of the 700C ordering steel exhibited basically identical features to the as-quenched steel, but with the coarser B2 domains, finer D03 particles, and less disordered ferrite. By contrast, the D03 domains were mainly observed in ferrite of the 500C ordering steel. The yield strength of the 500C ordering steel was higher than other two steels, which showed the similar yield strengths. The elongation of the as-quenched steel was higher than two ordering-treated steels. Deformation of austenite was manifested by the ? phase shearing by planar gliding dislocations. Intensive interactions of superdislocations were mainly observed in ferrite, depending on the type of the ordered phase. Factors influencing the strength and deformation behavior of the low-density duplex steel were discussed based on observation of deformed microstructure. Overall, the high-Mn/Al duplex steels with the ordered phases exhibit the high specific strength, the low density, and the moderate strain hardening that are suitable for the structural use requiring high strength and light weight.

Park, Kyung-Tae; Hwang, Si Woo; Son, Chang Young; Lee, Jae-Kon

2014-09-01

265

Microstructures and Mechanical Properties of Nano/Ultrafine-Grained N-Bearing, Low-Ni Austenitic Stainless Steels  

NASA Astrophysics Data System (ADS)

The nitrogen (N)-bearing austenitic stainless steels are new materials with interesting mechanical properties such as high strength and ductility, desirable toughness and work hardening, and good corrosion resistance. This work attempted to investigate the effect of N addition from 0.08 to 0.35 wt.% on grain refinement of the 201L austenitic stainless steel using the martensite thermomechanical process. This process was composed of cold rolling up to the thickness reduction of 90 % followed by reversion annealing at 800 C for 60 and 1800 s. It was found that increasing N content resulted in an increase in the austenite grain size for short annealing duration (e.g. 60 s), but caused a decrease in the austenite grain size for long annealing duration (e.g. 1800 s). The smallest austenite grain size of about 150 nm was achieved for the 201L steel containing 0.08 wt.% N after reversion annealing at 800 C for 60 s. The mechanical properties of the reversion-annealed N-bearing steels were enhanced due to both N alloying and grain refinement.

Saeedipour, S.; Kermanpur, A.; Najafizadeh, A.; Abbasi, M.

2015-02-01

266

Electro-mechanical coupling of semiconductor film grown on stainless steel by oxidation  

NASA Astrophysics Data System (ADS)

Electro-mechanical coupling phenomenon in oxidation film on stainless steel has been discovered by using current-sensing atomic force microscopy, along with the I-V curves measurements. The oxidation films exhibit either ohmic, n-type, or p-type semiconductor properties, according to the obtained I-V curves. This technique allows characterizing oxidation films with high spatial resolution. Semiconductor properties of oxidation films must be considered as additional stress corrosion cracking mechanisms.

Lin, M. C.; Wang, G.; Guo, L. Q.; Qiao, L. J.; Volinsky, Alex A.

2013-09-01

267

Galvanised steel to aluminium joining by laser and GTAW processes  

SciTech Connect

A new means of assembling galvanised steel to aluminium involving a reaction between solid steel and liquid aluminium was developed, using laser and gas tungsten arc welding (GTAW) processes. A direct aluminium melting strategy was investigated with the laser process, whereas an aluminium-induced melting by steel heating and heat conduction through the steel was carried out with the GTAW process. The interfaces generated during the interaction were mainly composed of a 2-40 {mu}m thick intermetallic reaction layers. The linear strength of the assemblies can be as high as 250 N/mm and 190 N/mm for the assemblies produced respectively by laser and GTAW processes. The corresponding failures were located in the fusion zone of aluminium (laser assemblies), or in the reaction layer (GTAW assemblies)

Sierra, G. [CEA/DRT/DTEN/LITEN/UTIAC, Groupement d'Etudes et de Recherche pour l'Application Industrielle des Lasers de Puissance (GERAILP), Arcueil, 94114 (France); Universite Montpellier 2, Laboratoire de Mecanique et Genie Civil, UMR 5508 CNRS, Montpellier, 34095 (France); Peyre, P. [GIP-GERAILP, Laboratoire pour l'Application des Lasers de Puissance, UPR 1578 CNRS, Arcueil, 94114 (France); Deschaux Beaume, F. [Universite Montpellier 2, Laboratoire de Mecanique et Genie Civil, UMR 5508 CNRS, Montpellier, 34095 (France)], E-mail: deschaux@iut-nimes.fr; Stuart, D. [GIP-GERAILP, Laboratoire pour l'Application des Lasers de Puissance, UPR 1578 CNRS, Arcueil, 94114 (France); Fras, G. [Universite Montpellier 2, Laboratoire de Mecanique et Genie Civil, UMR 5508 CNRS, Montpellier, 34095 (France)

2008-12-15

268

Response of Phase Transformation Inducing Heat Treatments on Microstructure and Mechanical Properties of Reduced Activation Ferritic-Martensitic Steels of Varying Tungsten Contents  

NASA Astrophysics Data System (ADS)

Microstructure and mechanical properties of 9Cr-W-0.06Ta Reduced Activation Ferritic-Martensitic (RAFM) steels having various tungsten contents ranging from 1 to 2 wt pct have been investigated on subjecting the steels to isothermal heat treatments for 5 minutes at temperatures ranging from 973 K to 1473 K (700 C to 1200 C) (below Ac1 to above Ac3) followed by oil quenching and tempering at 1033 K (760 C) for 60 minutes. The steels possessed tempered martensite structure at all the heat-treated conditions. Prior-austenitic grain size of the steels was found to decrease on heating in the intercritical temperature range (between Ac1 and Ac3) and at temperatures just above the Ac3 followed by increase at higher heating temperatures. All the steels suffered significant reduction in hardness, tensile, and creep strength on heating in the intercritical temperature range, and the reduction was less for steel having higher tungsten content. Strength of the steels increased on heating above Ac3 and was higher for higher tungsten content. Transmission Electron Microscopy (TEM) investigations of the steels revealed coarsening of martensitic substructure and precipitates on heating in the intercritical temperature range, and the coarsening was relatively less for higher tungsten content steel, resulting in less reduction in tensile and creep strength on intercritical heating. Tensile and creep strengths of the steels at different microstructural conditions have been rationalized based on the estimated inter-barrier spacing to dislocation motion. The study revealed the uniqueness of inter-barrier spacing to dislocation motion in determining the strength of tempered martensitic steels subjected to different heat treatments.

Chandravathi, K. S.; Laha, Kinkar; Sasmal, C. S.; Parameswaran, P.; Nandagopal, M.; Tailor, H. M.; Mathew, M. D.; Jayakumar, T.; Rajendra Kumar, E.

2014-09-01

269

Aging behavior and mechanical properties of maraging steels in the presence of submicrocrystalline Laves phase particles  

SciTech Connect

Cold rolling and annealing of homogenized Fe-Ni-Mn-Mo-Ti-Cr maraging steels resulted in the formation of submicrocrystalline Fe{sub 2}(Mo,Ti) Laves phase particles. Optical and scanning electron microscopy, X-ray diffraction, tensile and hardness tests were used to study the microstructure, aging behavior and mechanical properties of the annealed steels. The annealed microstructures showed age hardenability during subsequent isothermal aging at 753 K. Ultrahigh fracture stress but poor tensile ductility was obtained after substantial age hardening in the specimens with 2% and 4% chromium. Increasing chromium addition up to 6% toughened the aged microstructure at the expense of the fracture stress by increasing the volume fraction of retained austenite. The Laves phase particles acted as crack nucleation sites during tensile deformation. - Highlights: {yields} Laves phases dispersed in a BCC iron matrix by annealing of cold rolled samples. {yields} The samples showed age hardenability during subsequent isothermal aging at 753 K. {yields} Ultrahigh fracture stress but poor ductility was obtained after age hardening. {yields} Increasing chromium addition toughened the aged microstructure. {yields} Laves phase particles acting as crack nucleation sites during tensile deformation.

Mahmoudi, A., E-mail: abbasm1363@gmail.com [Young Researchers Club, Ahar Branch, Islamic Azad University, P.O. Box 54516, Ahar (Iran, Islamic Republic of); Ghavidel, M.R. Zamanzad [Young Researchers Club, Ahar Branch, Islamic Azad University, P.O. Box 54516, Ahar (Iran, Islamic Republic of); Nedjad, S. Hossein [Faculty of Materials Engineering, Sahand University of Technology, P. O. Box: 51335-1996, Tabriz (Iran, Islamic Republic of); Heidarzadeh, A. [Young Researchers Club, Ahar Branch, Islamic Azad University, P.O. Box 54516, Ahar (Iran, Islamic Republic of); Ahmadabadi, M. Nili [School of Metallurgy and Materials Engineering, University of Tehran, P. O. Box: 14395-731, Tehran (Iran, Islamic Republic of)

2011-10-15

270

Mechanically Robust Superhydrophobic Steel Surface with Anti-Icing, UV-Durability, and Corrosion Resistance Properties.  

PubMed

A superhydrophobic steel surface was prepared through a facile method: combining hydrogen peroxide and an acid (hydrochloric acid or nitric acid) to obtain hierarchical structures on steel, followed by a surface modification treatment. Empirical grid maps based on different volumes of H2O2/acid were presented, revealing a wettability gradient from "hydrophobic" to "rose effect" and finally to "lotus effect". Surface grafting has been demonstrated to be realized only on the oxidized area. As-prepared superhydrophobic surfaces exhibited excellent anti-icing properties according to the water-dripping test under overcooled conditions and the artificial "steam-freezing" (from 50 C with 90% humidity to the -20 C condition) test. In addition, the surfaces could withstand peeling with 3M adhesive tape at least 70 times with an applied pressure of 31.2 kPa, abrasion by 400 grid SiC sandpaper for 110 cm under 16 kPa, or water impacting for 3 h without losing superhydrophobicity, suggesting superior mechanical durability. Moreover, outstanding corrosion resistance and UV-durability were obtained on the prepared surface. This successful fabrication of a robust, anti-icing, UV-durable, and anticorrosion superhydrophobic surface could yield a prospective candidate for various practical applications. PMID:25749123

Wang, Nan; Xiong, Dangsheng; Deng, Yaling; Shi, Yan; Wang, Kun

2015-03-25

271

Influence of temperature, chloride ions and chromium element on the electronic property of passive film formed on carbon steel in bicarbonate\\/carbonate buffer solution  

Microsoft Academic Search

The influences of temperature, chloride ions and chromium element on the electronic property of passive film formed on carbon steel in NaHCO3\\/Na2CO3 buffer solution are investigated by capacitance measurement and electrochemical impedance spectroscopy (EIS). The results show that the passive film appears n-type semiconductive character; with increasing the solution temperature, the addition of chromium into carbon steel and increasing the

D. G. Li; Y. R. Feng; Z. Q. Bai; J. W. Zhu; M. S. Zheng

2007-01-01

272

Effect of yttrium addition on the microstructure and mechanical properties of ODS RAF steels  

NASA Astrophysics Data System (ADS)

An oxide dispersion strengthened (ODS) alloy with nominal composition Fe-14Cr-2W-0.3Ti-0.24Y (wt.%) was produced by mechanical alloying using elemental powders, and subsequent hot isostatic pressing. The microstructure of the material and characteristics of the oxide particle dispersion were investigated by electron microscopy. The effect of heat treatments on the microhardness and tensile properties at room temperature was also studied. The results show that a fine dispersion of Y-O-rich nanoparticles is achieved, together with larger (Cr, Ti)-rich precipitates. The absence of Ti is apparent in the majority of these nanoparticles, in contrast with reported results for ODS Ti-modified steels processed with Y2O3 addition.

Auger, M. A.; de Castro, V.; Leguey, T.; Tarcsio-Costa, J.; Monge, M. A.; Muoz, A.; Pareja, R.

2014-12-01

273

Sigma phase precipitation and properties of super-duplex stainless steel UNS S32750 aged at the nose temperature  

Microsoft Academic Search

The nose temperature for ?-phase precipitation in super-duplex stainless steel (SDSS) UNS S32750 was evaluated by hardness method. Color-optical microscopy,\\u000a scanning electron microscopy, energy spectrum analysis, impact and corrosion testing were carried out to investigate characteristics\\u000a of microstructure and properties of the SDSS aged at the nose temperature. The experimental results indicate that the nose\\u000a temperature of precipitation is 920

Dening Zou; Ying Han; Wei Zhang; Junhui Yu

2011-01-01

274

Heat treatment effects on the microstructure and mechanical properties of a medium manganese steel (0.2C-5Mn)  

Microsoft Academic Search

Microstructures and mechanical properties of 0.2C-5Mn steel processed under different heat treatment conditions were examined by scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and x-rays diffraction (XRD). It was found that high temperature austenization (above Ac3) resulted in a full martensite structure after quenching, which gradually transformed into the ferrite\\/austenite duplex structure during the following annealing process. However, austenization

H. F. Xu; J. Zhao; W. Q. Cao; J. Shi; C. Y. Wang; J. Li; H. Dong

275

Mechanical properties of a CrNiMoAlTi maraging steel in the process of martensitic transformation  

Microsoft Academic Search

Mechanical properties of a CrNiMoAlTi maraging steel are studied experimentally in the process of martensitic transformation. The transformation-start and -finish temperatures are determined from the dilatometric curves under a tensile, compressive or shear hold stress. An anomalous temperature-dependence of the yield stress is investigated. By checking the closing of the dilatometric loop in a full heatingannealingcooling thermal cycle under the

K Nagayama; T Terasaki; K Tanaka; F. D Fischer; T Antretter; G Cailletaud; F Azzouz

2001-01-01

276

Investigation on Mechanical Properties of 9%Cr/CrMoV Dissimilar Steels Welded Joint  

NASA Astrophysics Data System (ADS)

Advanced 9%Cr steel with good heat resistance and CrMoV with good toughness were chosen as candidate materials to fabricate combined rotor for steam turbine operating at over 620 C. But the great difference in base metals properties presents a challenge in achieving sound defect-free joint with optimal properties in dissimilar welded rotor. In this paper, appropriate selection of filler metal, welding parameters, and post-weld heat treatment was combined to successfully weld 1100-mm-diameter 9%Cr/CrMoV dissimilar experimental rotor through ultra-narrow gap submerge arc welding. Some properties such as hardness, low-cycle fatigue (LCF), and high-cycle fatigue (HCF) combined with microstructural characterization qualify the integrity of the weld. Microstructural analysis indicated the presence of high-temperature tempered martensite as the phase responsible for the improved properties obtained in the weld. The Coffin-Manson parameters were obtained by fitting the data in LCF test, while the conditional fatigue strength was derived from the HCF test based on S-N curve. Analysis of hardness profile showed that the lowest value occurred at heat-affected zone adjacent to base metal which represents the appropriate location of fracture for the samples after LCF and HCF tests.

Liu, Xia; Lu, Fenggui; Yang, Renjie; Wang, Peng; Xu, Xiaojin; Huo, Xin

2015-04-01

277

Investigation on Mechanical Properties of 9%Cr/CrMoV Dissimilar Steels Welded Joint  

NASA Astrophysics Data System (ADS)

Advanced 9%Cr steel with good heat resistance and CrMoV with good toughness were chosen as candidate materials to fabricate combined rotor for steam turbine operating at over 620 C. But the great difference in base metals properties presents a challenge in achieving sound defect-free joint with optimal properties in dissimilar welded rotor. In this paper, appropriate selection of filler metal, welding parameters, and post-weld heat treatment was combined to successfully weld 1100-mm-diameter 9%Cr/CrMoV dissimilar experimental rotor through ultra-narrow gap submerge arc welding. Some properties such as hardness, low-cycle fatigue (LCF), and high-cycle fatigue (HCF) combined with microstructural characterization qualify the integrity of the weld. Microstructural analysis indicated the presence of high-temperature tempered martensite as the phase responsible for the improved properties obtained in the weld. The Coffin-Manson parameters were obtained by fitting the data in LCF test, while the conditional fatigue strength was derived from the HCF test based on S-N curve. Analysis of hardness profile showed that the lowest value occurred at heat-affected zone adjacent to base metal which represents the appropriate location of fracture for the samples after LCF and HCF tests.

Liu, Xia; Lu, Fenggui; Yang, Renjie; Wang, Peng; Xu, Xiaojin; Huo, Xin

2015-02-01

278

An Ultra-low Carbon, Thermomechanically Controlled Processed Microalloyed Steel: Microstructure and Mechanical Properties  

NASA Astrophysics Data System (ADS)

In the current study, a novel ultra-low carbon, high-molybdenum-bearing microalloyed steel has been thermomechanically processed. Transformation of this steel during continuous cooling has been assessed. Variation in the microstructure and mechanical properties at different finish rolling temperatures has been studied. The average grain size, misorientation of grain boundary, and distribution of ferrite grains have been analyzed by using electron backscatter diffraction. The lower yield strength (251 to 377 MPa) with moderate tensile strength (406 to 506 MPa) along with high ductility (30 to 47 pct) has been achieved in the selected range of finish rolling temperatures. Superior impact toughness value in the range of 153 to 162 J is obtained in the subsize specimen even at subzero temperatures (233 K [-40 C]), which is attributed to fine average ferrite grain size. The acicular ferrite dominated microstructure obtained at the 1023 K (750 C) finish rolling temperature is the most attractive microstructure for pipeline applications due to its excellent combination of strength and toughness.

Shukla, R.; Das, S. K.; Ravi Kumar, B.; Ghosh, S. K.; Kundu, S.; Chatterjee, S.

2012-12-01

279

Tensile Properties and Work Hardening Behavior of Laser-Welded Dual-Phase Steel Joints  

NASA Astrophysics Data System (ADS)

The aim of this investigation was to evaluate the microstructural change after laser welding and its effect on the tensile properties and strain hardening behavior of DP600 and DP980 dual-phase steels. Laser welding led to the formation of martensite and significant hardness rise in the fusion zone because of the fast cooling, but the presence of a soft zone in the heat-affected zone was caused by partial vanishing and tempering of the pre-existing martensite. The extent of softening was much larger in the DP980-welded joints than in the DP600-welded joints. Despite the reduction in ductility, the ultimate tensile strength (UTS) remained almost unchanged, and the yield strength (YS) indeed increased stemming from the appearance of yield point phenomena after welding in the DP600 steel. The DP980-welded joints showed lower YS and UTS than the base metal owing to the appearance of severe soft zone. The YS, UTS, and strain hardening exponent increased slightly with increasing strain rate. While the base metals had multi-stage strain hardening, the welded joints showed only stage III hardening. All the welded joints failed in the soft zone, and the fracture surfaces exhibited characteristic dimple fracture.

Farabi, N.; Chen, D. L.; Zhou, Y.

2012-02-01

280

Seismic damage control of steel bridge piers by adding low-yield-point steel (LYPS) plates  

NASA Astrophysics Data System (ADS)

Bridge piers with steel hollow box sections are widely used in Japan for highway bridges. Unlike the steel columns in buildings, these piers are designed with high width-thickness ratios of component plates. This makes them susceptible to damage during severe earthquakes. In order to improve the seismic performance, an energy absorption strategy which localizes damage in structural systems is proposed: concentrating damage in specially designed weak structural elements, with which energy is absorbed during earthquake. Here, Low yield point steel (LYPS) plates attached to steel pier are employed as the weak elements. LYPS is a new kind of material which has low yield stress (around 100 MPa), large ductility and adequate fatigue life. In case of earthquake events, LYPS plates yield to absorb energy and keep the main structure always elastic. In this way, damage is concentrated in LYPS plates which can be easily replaced after earthquake. The paper starts with construction of constitutive model of LYPS with verification by experiment. The energy absorption performance of LYPS plates is studied by 3-dimensional finite element analysis (3DFEM), and optimal design method is proposed.

Zheng, Yi; Abe, Masato; Fujino, Yozo; Wilde, Krzystof

1998-06-01

281

Phosphorus removal by electric arc furnace steel slag and serpentinite.  

PubMed

Electric arc furnace (EAF) steel slag and serpentinite were tested in columns either alone or mixed with limestone to determine their capacity to remove phosphorus (P) from a solution containing initially 20mg P/L (for 114 days) than 400mg P/L (for 21 days). EAF steel slag was nearly 100% efficient due to specific P adsorption onto metal hydroxides and precipitation of hydroxyapatite. Serpentinite also showed a good performance that decreased with time, adsorption appearing to be the dominant mechanism for P removal. Mixing limestone with these two materials did not improve their performance and in the case of serpentinite, it actually even decreased it. In 114 days of experimentation, serpentinite alone and the mixture of serpentinite and limestone removed 1.0mg P/g while in 180 days of experimentation, EAF steel slag and the mixture of slag and limestone removed an average of 2.2mg P/g, without attaining their maximum P removal potential. The void hydraulic retention time (HRTv) was a key factor for growing hydroxyapatite crystals and had a significant effect on P removal efficiency by EAF steel slag. A temporary increase in HRTv caused by clogging resulted in an increase in EAF steel slag efficiency (from 80% to almost 100%) towards the end of investigation. Results from this study indicate that the use of EAF steel slag in constructed wetlands or filter beds is a promising solution for P removal via adsorption and precipitation mechanisms. PMID:16564560

Drizo, Aleksandra; Forget, Christiane; Chapuis, Robert P; Comeau, Yves

2006-05-01

282

Formation of highly corrosion resistant stainless steel surface alloys for marine environments by laser surface alloying  

SciTech Connect

Austenitic stainless steels (SS) such as UNS S30403 are being used for numerous industrial applications due to their goad mechanical properties and weldability. However in aggressive marine environments such as seawater, they suffer from localized corrosion. Even though newly developed highly alloyed SS`s possess very high pitting resistance, they are susceptible to the formation of secondary phases. In the present study, a laser surface alloying technique was employed for the formation of highly alloyed austenitic stainless steel surfaces on conventional 304 SS substrate. Microstructural characterization by optical and SEM revealed finer cells of austenitic phase in the laser alloyed zones with molybdenum contents in the range of 3 to 15 wt%. The pitting corrosion resistance of the surface alloys were ascertained by immersion and potentiodynamic polarization tests and the repassivation behavior by cyclic polarization tests. Also the influence of microstructural features on pitting behavior of highly alloyed and laser surface alloyed steels is studied.

Sridhar, K.; Deshmukh, M.B. [Naval Materials Research Lab., Bombay (India); Khanna, A.S. [Indian Inst. of Tech., Bombay (India); Wissenbach, K. [Fraunhofer Institut fuer Laser Technik, Aachen (Germany)

1998-12-31

283

Obtaining an Acicular Microstructure by Thermomechanical Sequences in X-80 Steel  

NASA Astrophysics Data System (ADS)

Microstructural modification is one of the routes to increase strength and toughness in high-strength low-alloy (HSLA) steels. Considering the good mechanical properties of acicular ferrite, thermomechanical sequences, with continuous cooling or isothermal treatment, were applied in an X-80 HSLA steel to obtain dominant acicular microstructure. Electron microscopy and electron back-scattered diffraction (EBDS) analyses were performed to identify and quantify microstructural changes. It was possible to correlate the misorientation boundaries profile with the occurrence of acicular microstructure, which was characterized by a high quantity of substructured and deformed units. Thermomechanical sequences with continuous cooling were more effective for obtaining acicular microstructure than sequences of isothermal treatments.

de Castro, Renato Soares; Pedrosa, Igor Rafael Vilarouco; Yadava, Yogendra Prasad; Ferreira, Ricardo Artur Sanguinetti

2014-09-01

284

Influence of explosive density on mechanical properties of high manganese steel explosion hardened  

NASA Astrophysics Data System (ADS)

The explosion hardening tests of high manganese steel were carried out by using two kinds of explosives of the same composition but different density, respectively. The detonation velocities were tested and the relevant mechanical properties were studied. The results show that the stronger single impulse acting on the specimen, the more hardness of surface increases and the more impact toughness decreases. Compared with the explosive of 1.48 g/cm3 density, the hardness, elongation rate, and impact toughness of the sample for triple explosion with explosive of 1.38 g/cm3 density are larger at the same hardening depth. In addition, the tensile strength of the sample for triple explosion with density of 1.38 g/cm3 is higher from the surface to 15 mm below the surface hardened.

Hu, Xiaoyan; Shen, Zhaowu; Liu, Yingbin; Liu, Tiansheng; Wang, Fengying

2013-12-01

285

Optical properties of plasma species absorbed during diamond deposition on steel  

NASA Astrophysics Data System (ADS)

Diamond thin films have been deposited directly on stainless steel substrates at low pressure and low temperature conditions over the range of methane (CH4) to hydrogen (H2) ratios of 4% to 9% using electron-cyclotron-resonance microwave plasma-assisted chemical vapor deposition (PACVD) technique. In situ Fourier transform infrared spectroscopy, employed in a reflection-absorption geometry (FTIRRAS), and optical emission spectroscopy have been used to study the plasma species adsorbed on the substrate surfaces as well as the species above the substrates surfaces both before and during the nucleation and film growth. It is demonstrated that these techniques can provide useful information on the early stages of diamond growth. When correlated with film properties measured by Raman spectroscopy and scanning electron microscopy, the results from FTIRRAS indicate that the absorption of the graphitic and diamond phases are related to the ratio of CH4 to H2 and can be identified at the early stages of film growth.

Shahedipour, F.; Conner, B. P.; White, H. W.

2000-09-01

286

Low cycle fatigue properties of 8Cr 2WVTa ferritic steel at elevated temperatures  

NASA Astrophysics Data System (ADS)

The effects of test temperature and tension holding on the fatigue properties of reduced activation ferritic/martensitic 8Cr-2WVTa (F-82H) steel were investigated by conducting low cycle fatigue tests at temperatures ranging from RT to 650C under the axial strain-controlled condition with strains ranging from 0.5% to 2.0%. Fatigue life data were formulated as strain-life equations. A large reduction in the fatigue life was recognized at temperatures above 600C. Softening without showing a saturated region was observed in the fatigue softening curves at temperatures above 600C. Tension holding during fatigue tests reduced the fatigue life at 400C, 500C and 600C. The microstructural examination showed that the large softening during cycle was associated with carbide (M 23C 6) coarsening and Laves phase (Fe 2W) precipitation at 600C.

Ishii, T.; Fukaya, K.; Nishiyama, Y.; Suzuki, M.; Eto, M.

1998-10-01

287

Influence of carbon, manganese and nickel on microstructure and properties of strong steel  

E-print Network

Influence of carbon, manganese and nickel on microstructure and properties of strong steel weld with 2 wt-% manganese. Nickel additions were beneficial to strength but detrimental to impact toughness. Significant segregation of nickel and manganese to interdendritic regions was observed at the two higher

Cambridge, University of

288

Influence of carbon, manganese and nickel on microstructure and properties of strong steel  

E-print Network

Influence of carbon, manganese and nickel on microstructure and properties of strong steel weld metals Part 2 ­ Impact toughness gain resulting from manganese reductions E. Keehan*1 , L. Karlsson2 , H with 7 wt-% nickel and either 2 or 0.5 wt-% manganese. Neural network predictions that it is advantageous

Cambridge, University of

289

Flexural properties of steel fiber-reinforced concretes at low temperatures  

Microsoft Academic Search

The mechanical properties of steel fiber-reinforced concrete (SFRC) at low temperatures were determined using the standard ASTM C1018 flexure test. The tests were performed at normal room temperature (20 C) at ?10 C and at ?30 C. In addition to the temperature, the variables investigated were the type of cement (both normal Portland cement and silica fume cement were used),

M. Pigeon; R. Cantin

1998-01-01

290

Enhanced Mechanical Properties of a Hot-Stamped Advanced High-Strength Steel via Tempering Treatment  

NASA Astrophysics Data System (ADS)

The hot stamping process has an extensive range of applications due to its advantages over the traditionally used stamping techniques developed in the past. To enhance the mechanical properties of the indirectly hot-stamped parts, the quenching and partitioning (Q&P) process has been recently applied on boron-alloyed steel. In the current research, it was observed that the tempering treatment on the directly hot-stamped boron steel resulted in better mechanical properties and higher formability index compared with the reported results using the Q&P process. The nano-carbide formation and the dislocation annihilation during the tempering treatment were suggested as the evident reasons for the occurrence of the mentioned robust properties. The ease of the practical implementation of the tempering route together with the markedly enhanced mechanical properties of the tempered parts make the suggested method privileged. Additionally, the variations in the yield strength before and after tempering were quantitatively evaluated.

Naderi, M.; Abbasi, M.; Saeed-Akbari, A.

2013-04-01

291

Quantitative study of multi-phases in TRIP-aided steels by means of neutron diffraction: a review  

NASA Astrophysics Data System (ADS)

The retained austenite and solute carbon in C-Si-Mn TRIP steels were quantitatively analyzed by neutron diffractometry, and their effects on the mechanical properties of the steels were studied. The decreasing of austempering temperature increased the volume fraction of retained austenite as well as the solute carbon in an austenite phase. However, the samples containing lower silicon showed a large variation in the amount of retained austenite and solute carbon in austenite with austempering temperature. The amount of retained austenite was proportional to the solute carbon in austenite. The elongation in TRIP steel was affected by both the volume fraction of retained austenite and the solute carbon in austenite.

Seong, B. S.; Maneewong, A.; Shin, E.; Lee, K. H.

2014-12-01

292

A mechanical property and stress corrosion evaluation of Custom 455 stainless steel alloy  

NASA Technical Reports Server (NTRS)

The mechanical and stress corrosion properties are presented of vacuum melted Custom 455 stainless steel alloy bar (1.0-inch diameter) and sheet (0.083-inch thick) material aged at 950 F, 1000 F, and 1050 F. Low temperature mechanical properties were determined at temperatures of 80 F, 0 F, -100 F, and -200 F. For all three aging treatments, the ultimate tensile and 0.2 percent offset yield strengths increased with decreasing test temperatures while the elongation held fairly constant down to -100 F and decreased at -200 F. Reduction in Area decreased moderately with decreasing temperature for the longitudinal round (0.250-inch diameter) specimens. Notched tensile strength and charpy V-notched impact strength decreased with decreasing test temperature. For all three aging treatments, no failures were observed in the unstressed specimens or the specimens stressed to 50, 75, and 100 percent of their yield strengths for 180 days of alternate immersion testing in a 3.5 percent NaCl solution. As indicated by the results of tensile tests performed after alternate immersion testing, the mechanical properties of Custom 455 alloy were not affected by stress or exposure under the conditions of the evaluation.

Montano, J. W.

1972-01-01

293

Correlation of microstructure and thermal-fatigue properties of centrifugally cast high-speed steel rolls  

NASA Astrophysics Data System (ADS)

This is a study of thermal-fatigue properties in centrifugally cast high-speed steel (HSS) rolls. The thermal-fatigue mechanism was investigated, with special focus on the roll microstructure and the increase in tensile stress which led the specimens to fracture when it reached the tensile strength. The thermal-fatigue test results indicated that the thermal-fatigue life decreased with increasing maximum temperature of the thermal-fatigue cycle. The results were then interpreted based on the amount of carbides and the cyclic-softening phenomenon associated with the exposed time to elevated temperatures. The coarse intercellular carbides on the specimen surface acted as fatigue-crack initiation sites as they cleaved at a low stress level to form cracks. The roll having the lowest matrix hardness and the smallest amount of intercellular carbides, thus, showed better thermal fatigue properties than the other rolls. For the improvement of the thermal-fatigue properties of the rolls, this study suggests a homogeneous distribution of carbides by reducing the carbide segregation formed along the solidification cell boundary and by optimizing the roll compositions.

Kim, Chang Kyu; Park, Jong Il; Ryu, Jae Hwa; Lee, Sunghak

2004-02-01

294

Tribological properties and surface structures of ion implanted 9Cr18Mo stainless steels  

NASA Astrophysics Data System (ADS)

The polished quenched-and-tempered 9Cr18Mo steels were implanted with N ions and Ti ions respectively at a fluence of 2 1017 ions/cm2. The mechanical properties of the samples were investigated by using nanoindenter and tribometer. The results showed that the ion implantations would improve the nanohardness and tribological property, especially N ion implantation. The surface analysis of the implanted samples was carried out by using XRD, XPS and AES. It indicated that the surface exhibits graded layers after ion implantation. For N ion implantation, the surface about 20 nm thickness is mainly composed of supersaturated interstitial N solid solution, oxynitrides, CrxCy phase and metal nitrides. In the subsurface region, the metal nitrides dominate and the other phases disappear. For Ti ion implantation, the surface of about 20 nm thickness is mainly composed of titanium oxides and carbon amorphous phase, the interstitial solid solution of Ti in Fe is abundant in the subsurface region. The surface components and structures have significant contributions to the improved mechanical properties.

Fengbin, Liu; Guohao, Fu; Yan, Cui; Qiguo, Sun; Min, Qu; Yi, Sun

2013-07-01

295

Microstructure, Texture, and Mechanical Property Analysis of Gas Metal Arc Welded AISI 304 Austenitic Stainless Steel  

NASA Astrophysics Data System (ADS)

The present study elaborately explains the effect of welding parameters on the microstructure, texture, and mechanical properties of gas metal arc welded AISI 304 austenitic stainless steel sheet (as received) of 4 mm thickness. The welded joints were prepared by varying welding speed (WS) and current simultaneously at a fixed heat input level using a 1.2-mm-diameter austenitic filler metal (AISI 316L). The overall purpose of this study is to investigate the effect of the variation of welding conditions on: (i) Microstructural constituents using optical microscope and transmission electron microscope; (ii) Micro-texture evolution, misorientation distributions, and grain boundaries at welded regions by measuring the orientation data from electron back scattered diffraction; and (iii) Mechanical properties such as hardness and tensile strength, and their correlation with the microstructure and texture. It has been observed that the higher WS along with the higher welding current (weld metal W1) can enhance weld metal mechanical properties through alternation in microstructure and texture of the weld metal. Higher ?-ferrite formation and high-angle boundaries along with the <101> + <001> grain growth direction of the weld metal W1 were responsible for dislocation pile-ups, SFs, deformation twinning, and the induced martensite with consequent strain hardening during tensile deformation. Also, fusion boundary being the weakest link in the welded structure, failure took place mainly at this region.

Saha, Saptarshi; Mukherjee, Manidipto; Pal, Tapan Kumar

2014-12-01

296

Microstructure, Texture, and Mechanical Property Analysis of Gas Metal Arc Welded AISI 304 Austenitic Stainless Steel  

NASA Astrophysics Data System (ADS)

The present study elaborately explains the effect of welding parameters on the microstructure, texture, and mechanical properties of gas metal arc welded AISI 304 austenitic stainless steel sheet (as received) of 4 mm thickness. The welded joints were prepared by varying welding speed (WS) and current simultaneously at a fixed heat input level using a 1.2-mm-diameter austenitic filler metal (AISI 316L). The overall purpose of this study is to investigate the effect of the variation of welding conditions on: (i) Microstructural constituents using optical microscope and transmission electron microscope; (ii) Micro-texture evolution, misorientation distributions, and grain boundaries at welded regions by measuring the orientation data from electron back scattered diffraction; and (iii) Mechanical properties such as hardness and tensile strength, and their correlation with the microstructure and texture. It has been observed that the higher WS along with the higher welding current (weld metal W1) can enhance weld metal mechanical properties through alternation in microstructure and texture of the weld metal. Higher ?-ferrite formation and high-angle boundaries along with the <101> + <001> grain growth direction of the weld metal W1 were responsible for dislocation pile-ups, SFs, deformation twinning, and the induced martensite with consequent strain hardening during tensile deformation. Also, fusion boundary being the weakest link in the welded structure, failure took place mainly at this region.

Saha, Saptarshi; Mukherjee, Manidipto; Pal, Tapan Kumar

2015-03-01

297

Microstructure and mechanical properties of weld fusion zones in modified 9Cr1Mo steel  

Microsoft Academic Search

Modified 9Cr-1Mo steel finds increasing application in power plant construction because of its excellent high-temperature\\u000a properties. While it has been shown to be weldable and resistant to all types of cracking in the weld metal and heat-affected\\u000a zone (HAZ), the achievement of optimum weld metal properties has often caused concern. The design of appropriate welding consumables\\u000a is important in this

M. Sireesha; S. Sundaresan; Shaju K. Albert

2001-01-01

298

Nitriding of austenitic stainless steel by plasma immersion ion implantation  

Microsoft Academic Search

Plasma immersion ion implantation (PI3), in which the diffusion of nitrogen from a low pressure r.f. plasma is combined with the implantation of nitrogen ions at energies up to 45 kV, is an effective means of nitriding austenitic stainless steel. At temperatures up to 450 C, tribological properties can be improved without loss of corrosion resistance. In common with other

G. A. Collins; R. Hutchings; K. T. Short; J. Tendys; X. Li; M. Samandi

1995-01-01

299

The aging behavior of types 308 and 308CRE stainless steels and its effect on mechanical properties  

SciTech Connect

Aging of 308 and 308CRE SS was studied at 475 to 850/sup 0/C for aging times up to 10,000 hours. Above 550/sup 0/C, aging of 308 steel resulted in precipitation of carbides and the transformation of ferrite to sigma phase or the formation of sigma phase in initially ferrite-free material. The elevated-temperature aging of 308CRE steel resulted in the precipitation of titanium-rich carbides, nitrides, and sulfides, and the transformation of ferrite to sigma phase. The distribution of precipitates was affected by the initial condition of the materials. The elevated-temperature creep properties, and in particular the improved properties of 308CRE, were related to the precipitate distribution. Below 550/sup 0/C, aging of welded type 308 steel, precipitation of G-phase within the ferrite was observed, as well as the decomposition of ferrite into alpha and alpha prime. With the help of a novel mechanical properties microprobe, which was capable of determining the hardness of the minor constituent ferrite phase, the hardness behavior as a function of aging could be related to the microstructures. These results are interpreted in terms of the potential susceptibility of these alloys to 475/sup 0/C embrittlement.

Vitek, J.M.; David, S.A.

1987-01-01

300

Effects of sour crude oil on fatigue properties of steel plates for shipbuilding  

SciTech Connect

The concentration of diffusible hydrogen introduced into steel was measured, and fatigue crack growth tests and fatigue life tests were carried out in sour crude oil containing a high concentration of hydrogen sulfide and under electrolytic hydrogen-charging conditions in neutral solution, using a high strength steel produced by the thermo-mechanical control process (TMCP) and a mild steel which are steels for hull plates. Comparison of the results demonstrated that a very small amount of hydrogen such as that introduced into steel from sour crude oil under atmospheric pressure accelerated the fatigue crack growth in the high {Delta}K regime and shortened the fatigue life in the high stress range region, but did not shorten the fatigue life in the low stress region. The electrolytic hydrogen-charging condition appeared to be appropriate as a fatigue-crack-growth test environment to simulate sour crude oil. The deterioration of fatigue characteristics of the TMCP high strength steel was similar with that of the mild steel.

Ouchi, H.; Kobayashi, J. [Nippon Steel Corp., Chiba (Japan). Steel Research Labs.; Ishikawa, T.; Takezawa, H. [Nippon Steel Corp., Oita (Japan). Oita Research and Development Division; Ebara, R.; Yamada, Y. [Mitsubishi Heavy Industries, Ltd., Hiroshima (Japan). Hiroshima Research and Development Center

1994-12-31

301

Evolution of mechanical properties of M50 bearing steel due to rolling contact fatigue  

NASA Astrophysics Data System (ADS)

Current bearing life models significantly under predict the life of bearings made of modern ultra-clean steels. New life models that include the constitutive response of the material are needed. However, the constitutive response of bearing steel is known to change during bearing operation. In the current study, the evolution of the mechanical properties of M50 bearing steel due to rolling contact fatigue (RCF) was investigated. A combination of M50 balls and rods were subjected to RCF testing under various conditions (e.g. number of RCF cycles, applied Hertzian stress, and interacting material). Additionally, some of the balls tested went through a proprietary mechanical process to induce compressive residual stresses over the first several hundred microns into the depth of the ball prior to RCF testing. After RCF testing, the specimens were subjected to a number of tests. First, the residual stresses within the subsurface RCF affected region were measured via x-ray diffraction. The residual stresses within the mechanically processed (MP) balls were found to not significantly change due to RCF, while a linear relationship was found between the maximum residual stress with the RCF affected zone and the Hertzian stress for the unprocessed balls. Then, the specimens were sectioned, polished, and chemically etched to study the evolution of the microstructure due to RCF. A similar relationship was found between the size of the dark etching region (DER) and the Hertzian stress. Formation of a light etching region (LER) is demonstrated to not correlate with a decrease in material strength and hardness, but it does serve as a predictor for failure due to spall. Micro-indentation was performed within subsurface to estimate the local yield stress. Micro-indentation is not able to provide information about the stress-strain response, only the yield strength. Hence, a novel method to extract and test miniature compression specimens from within the RCF affected regions of balls after RCF was developed. Using this method, it is possible to determine the full stress-strain response of material after material that has undergone RCF. The micro-hardness of the material within the RCF affected region was found to increase by nearly 10% and yield strength increased 13% when high contact stress levels were employed in fatigue experiments. It was demonstrated that the number of cycles does contribute to hardness increase, but the applied Hertzian stress is the dominant factor. Mechanical processing was found to significantly retard the rate of mechanical property evolution, implying that it would also significantly improve the life. Similarly, it was observed that the rate of hardening is slower when silicon nitride is used to interact with the M50 specimen than another M50 component. This supports the idea that hybrid bearings last longer than more traditional all-steel bearings. Finally, an empirical model of the evolution of the constitutive response of the bearing material within the RCF affected region was developed based on the results of these analyses. This model can be used to predict the constitutive response of the material within the RCF affected region of an M50 steel ball, given the initial hardness, number of RCF cycles, and applied Hertzian stress. Further, it is now possible to solve the local yield strength as a function of depth within the RCF affected region given these same parameters.

Allison, Bryan D.

302

Effects of mechanical alloying time on microstructure and properties of 9Cr-ODS steels  

NASA Astrophysics Data System (ADS)

Pre-alloyed powders of oxide dispersion strengthened (ODS) steels were produced by atomization. The atomized powders without mechanical alloying (MA) and with short-time MA were consolidated by hot isostatic pressing (HIP). The morphology and microstructure of the atomized and the MA powders were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The microstructure of 9Cr-ODS steels with different MA time was characterized by high-resolution transmission electron microscopy (HRTEM), electron backscatter diffraction (EBSD) and atom probe tomography (APT). The results showed that high-density of nanosized precipitates and ultrafine grains are formed in the ODS steels using the processing route, which remarkably reduce MA time. The yield strength and ultimate tensile strength of ODS steels are improved with the increase of MA time.

Xie, Rui; Lu, Zheng; Lu, Chenyang; Liu, Chunming

2014-12-01

303

Formation of Wear Resistant Steel Surfaces by Plasma Immersion Ion Implantation  

SciTech Connect

Plasma immersion ion implantation (PIII) is a versatile and fast method for implanting energetic ions into large and complex shaped three-dimensional objects where the ions are accelerated by applying negative high voltage pulses to a substrate immersed in a plasma. As the line-of-sight restrictions of conventional implanters are circumvented, it results in a fast and cost-effective technology. Implantation of nitrogen at 30 - 40 keV at moderate temperatures of 200 - 400 deg. C into steel circumvents the diminishing thermal nitrogen activation encountered, e.g., in plasma nitriding in this temperature regime, thus enabling nitriding of additional steel grades. Nitride formation and improvement of the mechanical properties after PIII are presented for several steel grades, including AISI 316Ti (food industry), AISI D2 (used for bending tools) and AISI 1095 (with applications in the textile industry)

Maendl, S.; Rauschenbach, B. [Institute fuer Oberflaechenmodifizierung, 04303 Leipzig (Germany)

2003-08-26

304

GASEOUS HYDROGEN EFFECTS ON THE MECHANICAL PROPERTIES OF CARBON AND LOW ALLOY STEELS (U)  

SciTech Connect

This report is a compendium of sets of mechanical properties of carbon and low alloy steels following the short-term effects of hydrogen exposure. The property sets include the following: Yield Strength; Ultimate Tensile Strength; Uniform Elongation; Reduction of Area; Threshold Cracking, K{sub H} or K{sub th}; Fracture Toughness (K{sub IC}, J{sub IC}, and/or J-R Curve); and Fatigue Crack Growth (da/dN). These properties are drawn from literature sources under a variety of test methods and conditions. However, the collection of literature data is by no means complete, but the diversity of data and dependency of results in test method is sufficient to warrant a design and implementation of a thorough test program. The program would be needed to enable a defensible demonstration of structural integrity of a pressurized hydrogen system. It is essential that the environmental variables be well-defined (e.g., the applicable hydrogen gas pressure range and the test strain rate) and the specimen preparation be realistically consistent (such as the techniques to charge hydrogen and to maintain the hydrogen concentration in the specimens).

Lam, P

2006-06-08

305

Predictions of the Mechanical Properties and Microstructure Evolution of High Strength Steel in Hot Stamping  

NASA Astrophysics Data System (ADS)

Hot stamping is an innovative operation in metal-forming processes which virtually avoids the cracking and wrinkling of high strength steel (HSS) sheets. Examining the phase transformation and mechanical properties of HSS by means of experiments is challenging. In this article, a numerical model of the hot stamping process including forming, quenching, and air cooling was developed to reveal the microstructure evolution and to predict the final mechanical properties of hot-stamped components after multi-process cycles. The effects of the number of process cycles and the holding times on the temperature of HSS were examined using the model. The microstructure evolution of HSS under variable holding times is illustrated. The mechanical properties, particularly hardness and tensile strength, were predicted. It was found that the martensitic content increased with increasing holding time, and the martensitic content of the formed component at the flange and end was higher than for the sidewall, and lowest for the bottom. The hardness trend was consistent with the martensitic content. After six process cycles, the predictive errors of the model for hardness and tensile strength were acceptable for practical applications in engineering. Comparison between the predicted results and the experiment results showed that the developed model was reliable.

Cui, Junjia; Lei, Chengxi; Xing, Zhongwen; Li, Chunfeng; Ma, Shumei

2012-11-01

306

Basic properties of steel plant dust and technological properties of direct reduction  

NASA Astrophysics Data System (ADS)

Basic physicochemical properties of the dust from Laiwu Iron and Steel Co. Ltd. were studied. It is found that C, Zn, K, Na, etc. exist in the fabric filter dust, off gas (OG) sludge, fine ash in converter, and electrical field dust in sinter. Among these, OG sludge gives the finest particle, more than 90% of which is less than 2.51 ?m. The dust can lead to a serious negative influence on the production of sintering and blast furnaces (BF) if it is recycled in sintering. The briquette and reduction experimental results showed that the qualified strength could be obtained in the case of 8wt% molasses or 4wt% QT-10 added as binders. Also, more than 75% of metallization ratio, more than 95% of dezincing ratio, as well as more than 80% of K and Na removal rates were achieved for the briquettes kept at 1250C for 15 min during the direct reduction process. SEM observation indicated that the rates of indirect reduction and carbonization became dominating when the briquettes were kept at 1250C for 6 min.

She, Xue-Feng; Wang, Jing-Song; Xue, Qing-Guo; Ding, Yin-Gui; Zhang, Sheng-Sheng; Dong, Jie-Ji; Zeng, Hui

2011-06-01

307

Comparison of properties of steel slag and crushed limestone aggregate concretes  

Microsoft Academic Search

Steel slag is produced as a by-product during the oxidation of steel pellets in an electric arc furnace. This by-product that mainly consists of calcium carbonate is broken down to smaller sizes to be used as aggregates in asphalt and concrete. They are particularly useful in areas where good-quality aggregate is scarce. This research study was conducted to evaluate the

M Maslehuddin; Alfarabi M Sharif; M Shameem; M Ibrahim; M. S Barry

2003-01-01

308

Acceleration of irradiation hardening of low-copper reactor pressure vessel steel observed by means of SANS and tensile testing  

Microsoft Academic Search

Neutron irradiation of low-copper reactor pressure vessel steels containing manganese and nickel gives rise to microstructural changes and a deterioration of mechanical properties. This deterioration apparently progresses slower than in steels containing more than ?0.1 wt% Cu. An acceleration of this process after the accumulation of a threshold fluence caused by the so-called late blooming phases is a matter of

F. Bergner; A. Ulbricht; H.-W. Viehrig

2009-01-01

309

Effect of Inclusions and Microstructural Characteristics on the Mechanical Properties and Fracture Behavior of a High- Strength Low- Alloy Steel  

NASA Astrophysics Data System (ADS)

The strength and toughness properties of hot- rolled plates from three commercial heats of a highstrength low-alloy steel were investigated with respect to their intrinsic microstructural and inclusion characteristics. One heat was argon purged and contained relatively higher carbon and sulfur, whereas the other two heats, with lower carbon and sulfur levels, were sulfide shape controlled. The study revealed that although yield and tensile strengths specific to a heat were unaffected by testing direction, the anisotropy in tensile ductility was greater in steels with stringered sulfides. Despite similar grain sizes in all the steels, Charpy shelf energy and impact transition temperature were significantly affected by pearlite content and sulfide morphology and to a lesser extent by pearlite banding. The modification of stringer sulfides to tiny lenticular/globular oxysulfides resulted in considerably higher shelf energies, lowering of impact transition temperatures, and minimal anisotropy of impact properties. The macroscopic appearance of splitting on the fracture surfaces of transverse Charpy specimens associated with low impact energies confirmed failure by a low- energy mode. The presence of pancake- shaped ferrite grains and fractographic evidence of inclusion stringers inside furrows identified their role in accentuating the splitting phenomenon.

Ray, A.; Paul, S. K.; Jha, S.

1995-12-01

310

Effect of Vanadium Nitride Precipitation on Martensitic Transformation and Mechanical Properties of CrMnNi Cast Austenitic Steels  

NASA Astrophysics Data System (ADS)

The microstructural evolution and mechanical properties of two cast Fe-15Cr-6Mn-3Ni-0.5Si-0.2N-0.1C (concentrations in wt pct) steels containing no vanadium and 0.65 wt pct vanadium were investigated under uniaxial tensile loading for room temperature (RT) and 373 K (100 C). The alloy development was focused on the formation of nanosized vanadium nitride precipitates in the austenite to serve as obstacles to dislocation motion. The austenitic steels exhibited transformation- and twinning-induced plasticity (TRIP/TWIP) effects and the planar glide of dislocations in the austenite. The triggering stress for the RT strain-induced ? ???' formation increased by 190 MPa, and the transformation occurred at higher strain levels due to the presence of VN precipitates. The occurrence of the TWIP effect during tensile testing at 373 K (100 C) of both steels resulted in engineering strains above 50 pct. The yield strength (YS) of the VN-containing steel was 420 MPa at RT, 52 MPa higher than the vanadium-free alloy. The difference increased to 59 MPa at 373 K (100 C) with the VN-containing alloy exhibiting a YS of 311 MPa.

Wendler, Marco; Reichel, Benedikt; Eckner, Ralf; Fabrichnaya, Olga; Krger, Lutz; Wei, Andreas; Mola, Javad

2014-12-01

311

Mechanical properties of thermally aged cast stainless steels from shippingport reactor components.  

SciTech Connect

Thermal embrittlement of static-cast CF-8 stainless steel components from the decommissioned Shippingport reactor has been characterized. Cast stainless steel materials were obtained from four cold-leg check valves, three hot-leg main shutoff valves, and two pump volutes. The actual time-at-temperature for the materials was {approx}13 y at {approx}281 C (538 F) for the hot-leg components and {approx}264 C (507 F) for the cold-leg components. Baseline mechanical properties for as-cast material were determined from tests on either recovery-annealed material, i.e., annealed for 1 h at 550 C and then water quenched, or material from the cooler region of the component. The Shippingport materials show modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength because of relatively low service temperatures and ferrite content of the steel. The procedure and correlations developed at Argonne National Laboratory for estimating mechanical properties of cast stainless steels predict accurate or slightly lower values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and JIC of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predicted the mechanical properties of the Ringhals 2 reactor hot- and crossover-leg elbows (CF-8M steel) after service of {approx}15 y and the KRB reactor pump cover plate (CF-8) after {approx}8 y of service.

Chopra, O. K.; Shack, W. J.; Energy Technology

1995-06-07

312

Mechanical properties of thermally aged cast stainless steels from Shippingport reactor components  

SciTech Connect

Thermal embrittlement of static-cast CF-8 stainless steel components from the decommissioned Shippingport reactor has been characterized. Cast stainless steel materials were obtained from four cold-leg check valves, three hot-leg main shutoff valves, and two pump volutes. The actual time-at-temperature for the materials was {approximately}13 y at {approximately}281 C (538 F) for the hot-leg components and {approximately}264 C (507 F) for the cold-leg components. Baseline mechanical properties for as-cast material were determined from tests on either recovery-annealed material, i.e., annealed for 1 h at 550 C and then water quenched, or material from the cooler region of the component. The Shippingport materials show modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength because of relatively low service temperatures and ferrite content of the steel. The procedure and correlations developed at Argonne National Laboratory for estimating mechanical properties of cast stainless steels predict accurate or slightly lower values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and J{sub IC} of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predicted the mechanical properties of the Ringhals 2 reactor hot and crossover-leg elbows (CF-8M steel) after service of {approximately} 15 y and the KRB reactor pump cover plate (CF-8) after {approximately} 8 y of service.

Chopra, O.K.; Shack, W.J. [Argonne National Lab., IL (United States)

1995-04-01

313

Evaluation of fatigue properties of 316FR stainless steel welded joints at elevated temperature  

SciTech Connect

316FR is an improved version of type 316 stainless steel for elevated temperature use with lower carbon content than conventional type 316 stainless steel. Fatigue properties of GTAW joints of 316FR stainless steel have been investigated. Heat affected zone (HAZ) of 316FR becomes harder than base metal. A method based on the stress-strain relationship of three elements, which are base metal, HAZ and weld portions, has been proposed and applied to the evaluations of fatigue tests. The tri-metal analysis model gives good agreements between experimental results and predicted fatigue lives of the 316FR welded joints. This material is to be used in the DFBR reactor in Japan.

Kaguchi, Hitoshi; Koto, Hiroyuki [Mitsubishi Heavy Industries, Ltd., Kobe (Japan); Fujioka, Terutaka [Japan Atomic Power Co., Tokyo (Japan); Taguchi, Kosei [Toshiba Corp., Yokohama (Japan); Sukekawa, Masayuki [Hitachi Ltd. (Japan)

1996-12-01

314

Study on the mechanical properties evolution of A508-3 steel under proton irradiation  

NASA Astrophysics Data System (ADS)

In an effort to study the effect of irradiation on the hardening behavior of reactor pressure vessel (RPV) steel, nanoindentation was employed to investigate the mechanical properties of A508-3 steel after an irradiation with 190 keV proton to the dose range of 0.054-0.271 displacement per atom (dpa) at room temperature. The results show that the relationship between the nanohardness and indent depth is in accordance with the Nix-Gao model. The nanohardness of A508-3 steel increases notably with the dose. In addition, the contribution of the irradiation-induced microstructural defects including matrix damage and nano clusters to the irradiation hardening is discussed.

Lei, Jing; Ding, Hui; Shu, Guo-gang; Wan, Qiang-mao

2014-11-01

315

Creep Rupture Properties of Welded Joints of Heat Resistant Steels  

NASA Astrophysics Data System (ADS)

In this study, the high-temperature mechanical and creep rupture properties of Grade 91/Grade 91 (Mod. 9Cr-Mo) similar welded joints and Grade 91/Inconel 82/SUS304 dissimilar welded joints were examined. The effects of temperature and stress on the failure location in the joints were also investigated. Creep rupture tests were conducted at 823, 873, and 923 K; the applied stress ranges were 160-240, 80-160, and 40-80 MPa, respectively. The creep rupture strengths of the specimens with welded joints were lower than those of the specimens of the base metal at all temperature levels; in addition, these differences in creep strength increased with temperature. After being subjected to long-term creep rupture tests, the fracture type exhibited by the dissimilar welded joints was transformed from Types V and VII to Type IV. It was estimated that the fracture type exhibited by the dissimilar welded joints after 100,000-h rupture strength tests at 823 K and 873 K was Type IV fracture.

Yamazaki, Masayoshi; Watanabe, Takashi; Hongo, Hiromichi; Tabuchi, Masaaki

316

Effect of crystallographic texture on the bulk magnetic properties of non-oriented electrical steels  

NASA Astrophysics Data System (ADS)

Quantitative physical models for non-oriented electrical steels require precise knowledge of chemical and microstructural parameters for the material, with crystallographic texture being one of the most important. Describing the structure-property relationships in these materials is made difficult in that all of the parameters have an effect on magnetic properties. In the present study, a set of non-oriented electrical steel specimens are examined, where chemistry and grain size are kept similar from sample to sample, but texture is varied. A new texture parameter called Magnetic Texture Factor is introduced which is defined as the ratio of the volume fractions of <100> direction to <111> direction along magnetization vector. It was found that this Magnetic Texture Factor was a better parameter for identifying trends of magnetic properties with crystallographic texture than the often used Texture Factor, which is described as the ratio of the volume fractions of {100} planes to {111} planes.

Ghosh, Pampa; Chromik, Richard R.; Vaseghi, Babak; Knight, Andrew M.

2014-09-01

317

Factors Affecting on Mechanical Properties of Soft Martensitic Stainless Steel Castings  

NASA Astrophysics Data System (ADS)

This paper details the factors affecting mechanical properties of soft martensitic stainless steel castings that have lower carbon contents and increased nickel contents of up to 6% compared with normal martensitic stainless steel castings. The effect of alloying elements and impurities on the microstructural features and tempering characteristics was considered in detail, with special reference to reverted austenite and temper embrittlement. The mechanical properties were also investigated, and it was shown that the best combination of strength and toughness is obtained when tempered at around 900K. Addition of Mo was shown to improve toughness degradation due to slow cooling from the tempering temperature. Lowering P and S contents leads to superior toughness and fatigue properties. The threshold stress intensity range was shown to decrease with increasing stress ratio, depending on P content.

Iwabuchi, Yoshitaka

318

Effects of Mn Addition on Tensile and Charpy Impact Properties in Austenitic Fe-Mn-C-Al-Based Steels for Cryogenic Applications  

NASA Astrophysics Data System (ADS)

Effects of Mn addition (17, 19, and 22 wt pct) on tensile and Charpy impact properties in three austenitic Fe-Mn-C-Al-based steels were investigated at room and cryogenic temperatures in relation with deformation mechanisms. Tensile strength and elongation were not varied much with Mn content at room temperature, but abruptly decreased with decreasing Mn content at 77 K (-196 C). Charpy impact energies at 273 K (0 C) were higher than 200 J in the three steels, but rapidly dropped to 44 J at 77 K (-196 C) in the 17Mn steel, while they were higher than 120 J in the 19Mn and 22Mn steels. Although the cryogenic-temperature stacking fault energies (SFEs) were lower by 30 to 50 pct than the room-temperature SFEs, the SFE of the 22Mn steel was situated in the TWinning-induced plasticity regime. In the 17Mn and 19Mn steels, however, ?'-martensites were formed by the TRansformation-induced plasticity mechanism because of the low SFEs. EBSD analyses along with interrupted tensile tests at cryogenic temperature showed that the austenite was sufficiently deformed in the 19Mn steel even after the formation of ?'-martensite, thereby leading to the high impact energy over 120 J.

Lee, Junghoon; Sohn, Seok Su; Hong, Seokmin; Suh, Byeong-Chan; Kim, Sung-Kyu; Lee, Byeong-Joo; Kim, Nack J.; Lee, Sunghak

2014-11-01

319

Influence of the PM-Processing Route and Nitrogen Content on the Properties of Ni-Free Austenitic Stainless Steel  

NASA Astrophysics Data System (ADS)

Ni-free austenitic steels alloyed with Cr and Mn are an alternative to conventional Ni-containing steels. Nitrogen alloying of these steel grades is beneficial for several reasons such as increased strength and corrosion resistance. Low solubility in liquid and ?-ferrite restricts the maximal N-content that can be achieved via conventional metallurgy. Higher contents can be alloyed by powder-metallurgical (PM) production via gas-solid interaction. The performance of sintered parts is determined by appropriate sintering parameters. Three major PM-processing routes, hot isostatic pressing, supersolidus liquid phase sintering (SLPS), and solid-state sintering, were performed to study the influence of PM-processing route and N-content on densification, fracture, and mechanical properties. Sintering routes are designed with the assistance of thermodynamic calculations, differential thermal analysis, and residual gas analysis. Fracture surfaces were studied by X-ray photoelectron spectroscopy, secondary electron microscopy, and energy dispersive X-ray spectroscopy. Tensile tests and X-ray diffraction were performed to study mechanical properties and austenite stability. This study demonstrates that SLPS process reaches high densification of the high-Mn-containing powder material while the desired N-contents were successfully alloyed via gas-solid interaction. Produced specimens show tensile strengths >1000 MPa combined with strain to fracture of 60 pct and thus overcome the other tested production routes as well as conventional stainless austenitic or martensitic grades.

Lefor, Kathrin; Walter, M.; Weddeling, A.; Hryha, E.; Huth, S.; Weber, S.; Nyborg, L.; Theisen, W.

2015-03-01

320

Surface modification of low alloy steel by laser melting  

Microsoft Academic Search

Surface modification of low alloy steel (LAS) has been achieved by laser melting and Ni alloying. Specimens of LAS were coated with Ni by PVD and electro-deposition techniques followed by laser beam melting. The Ni coating produced by PVD technique could not produce the requisite alloying during the laser melting. In case of LAS specimens coated electrochemically, the ironnickel binary

K. A. Qureshi; N. Hussain; J. I. Akhter; N. Khan; A. Hussain

2005-01-01

321

Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components  

SciTech Connect

The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950`s are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials and irradiation conditions has been produced for reactor tank structural analyses and to quantify the effects of radiation-induced materials degradation for evaluating reactor service life. The data has been collected from the SRL Reactor Materials Program (RMP) irradiations and testing of archival stainless steel weldment components and from previous SRL programs to measure properties of irradiated reactor Thermal Shield weldments and reactor tank (R-tank) sidewall material. Irradiation programs of the RMP are designed to quantify mechanical properties at tank operating temperatures following irradiation to present and future tank wall maximum exposure conditions. The exposure conditions are characterized in terms of fast neutron fluence (E{sub n} > 0.1 MeV) and displacements per atom (dpa){sup 3}. Tensile properties, Charpy-V notch toughness, and elastic-plastic fracture toughness were measured for base, weld, and weld heat-affected zone (HAZ) weldment components from archival piping specimens following a Screening Irradiation in the University of Buffalo Reactor (UBR) and following a Full-Term Irradiation in the High Flux Isotope Reactor (HFIR).

Sindelar, R.L.; Caskey, G.R. Jr.

1991-12-01

322

Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components  

SciTech Connect

The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950's are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials and irradiation conditions has been produced for reactor tank structural analyses and to quantify the effects of radiation-induced materials degradation for evaluating reactor service life. The data has been collected from the SRL Reactor Materials Program (RMP) irradiations and testing of archival stainless steel weldment components and from previous SRL programs to measure properties of irradiated reactor Thermal Shield weldments and reactor tank (R-tank) sidewall material. Irradiation programs of the RMP are designed to quantify mechanical properties at tank operating temperatures following irradiation to present and future tank wall maximum exposure conditions. The exposure conditions are characterized in terms of fast neutron fluence (E{sub n} > 0.1 MeV) and displacements per atom (dpa){sup 3}. Tensile properties, Charpy-V notch toughness, and elastic-plastic fracture toughness were measured for base, weld, and weld heat-affected zone (HAZ) weldment components from archival piping specimens following a Screening Irradiation in the University of Buffalo Reactor (UBR) and following a Full-Term Irradiation in the High Flux Isotope Reactor (HFIR).

Sindelar, R.L.; Caskey, G.R. Jr.

1991-12-01

323

Effect of Annealing Temperature on Microstructure and Mechanical Properties of Bulk 316L Stainless Steel with Nano- and Micro-crystalline Dual Phases  

NASA Astrophysics Data System (ADS)

Microstructures and mechanical properties of 316L stainless steels with dual phases austenite prepared by an aluminothermic reaction casting were explored. It is found that the steels consist of nano- and micro-crystalline austenite phases, a little ? ferrite and contaminations. Before and after annealing at 1073 K and 1273 K (800 C and 1000 C), average grain sizes of the nanocrystalline austenite phase are about 32, 31, 38 nm, respectively. Tensile strength increases first from 371 to 640 MPa and then decreases to 454 MPa. However, elongation ratio increases gradually from 16 to 23 and then 31 pct after annealing. The results illustrate that the steel after annealing at 1073 K (800 C) has better properties, also indicating that combination of dual nano- and micro-crystalline austenite phase is conductive to improving tensile properties of materials.

La, Peiqing; Wei, Fuan; Lu, Xuefeng; Chu, Chenggang; Wei, Yupeng; Wang, Hongding

2014-10-01

324

Tensile and Charpy impact properties of irradiated reduced-activation ferritic steels  

SciTech Connect

Tensile tests were conducted on 8 reduced-activation Cr-W steels after irradiation to 15-17 and 26-29 dpa, and Charpy impact tests were conducted on steels irradiated to 26-29 dpa. Irradiation was in Fast Flux Test Facility at 365 C on steels containing 2.25-12% Cr, varying amounts of W, V, and Ta, and 0.1%C. Previously, tensile specimens were irradiated to 6-8 dpa and Charpy specimens to 6-8, 15- 17, and 20-24 dpa. Tensile and Charpy specimens were also thermally aged to 20,000 h at 365 C. Thermal aging had little effect on tensile properties or ductile-brittle transition temperature (DBTT), but several steels showed a slight increase in upper-shelf energy (USE). After 7 dpa, strength increased (hardened) and then remained relatively unchanged through 26-29 dpa (ie, strength saturated with fluence). Post-irradiation Charpy impact tests after 26-29 dpa showed that the loss of impact toughness (increased DBTT, decreased USE) remained relatively unchanged from the values after 20-24 dpa, which had been relatively unchanged from the earlier irradiations. As before, the two 9Cr steels had the most irradiation resistance.

Klueh, R.L.; Alexander, D.J.

1996-10-01

325

Long-term aging of cast stainless steels: Mechanisms and resulting properties  

SciTech Connect

Mechanical property data are presented from Charpy-impact, tensile, and J-R curve tests for several heats of cast stainless steel aged up to 10,000 h at 450, 400, 350, 320, and 290/sup 0/C. The results indicate that thermal aging increases the tensile strength and decreases the impactenergy, J/sub IC/ and tearing modulus of the steels. Also, the ductile-to-brittle transition curve shifts to higher temperatures. The low-carbon CF-3 steels were the most resistant and the molybdenum-containing high-carbon CF-8M steels were the most susceptible to low-temperature embrittlement. The influence of nitrogen content and distribution of ferrite on loss of toughness are discussed. Data also indicate that existing correlations do not accurately represent the embrittlement behavior over the temperature range 280 to 450/sup 0/C, i.e., extrapolation of high-temperature data to reactor temperatures may not be valid for some compositions of cast stainless steels. 13 refs., 13 figs., 2 tabs.

Chopra, O.K.; Chung, H.M.

1987-09-01

326

The effect of preheat on the material properties of copper and steel in a lens process  

NASA Astrophysics Data System (ADS)

Working with pure copper powder deposited on a steel substrate is difficult in a laser additive manufacturing process due to the relatively high thermal conductivity and reflectivity of copper. In addition to these properties, the difference in thermal conductivity between the copper and steel presents an environment where cracking and porosity is present in the copper-steel transition. One application is the creation of steel-copper die casts for improved thermal management. Removing cracks and limiting porosity is of the utmost importance to this application. Through recent research at NIU, it has been observed that adding preheat while depositing copper and steel in a LAM process all but eliminates this transitional zone along with the cracking and porosity associated with it. This thesis will explore the effects of preheat, laser power, powder feed rate, and laser travel speed on the size of the transitional layer, the presence of cracks, porosity within the deposit, hardness, and all of the parameters effects on the bead and heat affected zone geometry.

Styrcula, Matt

327

Radiation attenuation and nuclear properties of high density concrete made with steel aggregates  

Microsoft Academic Search

The fast neutron and gamma ray spectra measured behind different thickness of steel scrap concrete with density of 4 g\\/cm3 have been studied. The mix proportions by weight of this type of concrete were 1 cement: 6.89 steel scrap: 2.9 sand and 0.5 Water. Comparison with a standard ordinary concrete of density 2.3 g\\/cm3 have been carried out. The measurements

I. I. Bashter

1997-01-01

328

Microstructures and mechanical properties of C-Mn-Cr-Nb and C-Mn-Si-Nb ultra-high strength dual-phase steels  

NASA Astrophysics Data System (ADS)

The microstructures and mechanical properties of C-Mn-Cr-Nb and C-Mn-Si-Nb ultra-high strength dual-phase steels were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and tensile test. The results show that Si can promote the transformation of austenite (?) to ferrite (?), enlarge the (?+?) region, and increase the aging stability of martensite by inhibiting carbide precipitation. Adding Cr leads to the formation of retained austenite and martensite/austenite (M/A) constituents, as well as the decomposition of martensite during the overaging stage. Both of the steels show higher initial strain-hardening rates and two-stage strain-hardening characteristics. The C-Mn-Si-Nb steel shows the higher strain-hardening rate than the C-Mn-Cr-Nb steel in the first stage; however, there is no significant difference in the second stage. Although the tensile strength and elongation of the two steels both exceed 1000 MPa and 15%, respectively, the comprehensive mechanical properties of the C-Mn-Si-Nb steel are superior.

Wang, Zhi-gang; Zhao, Ai-min; Zhao, Zheng-zhi; Ye, Jie-yun; Tang, Di; Zhu, Guo-sen

2012-10-01

329

Fast parallel computation algorithm in application to simulation of semi-solid steel rolling and inverse analysis of its properties  

NASA Astrophysics Data System (ADS)

The contribution deals with the problem of development of a fast computation system allowing for correct interpretation of results of experiments concerning mechanical properties of semi-solid steel. Accurate computer simulation of steel deformation at very high temperature requires information about plastic properties of the material. One of the most important properties of steel subjected to deformation is the stress-strain relationship - yield stress curve. Unlike low temperature tests, deformation of steel samples in temperatures over 1400C causes strain, stress and temperature fields that are strongly inhomogeneous from the physical point of view. Correct interpretation of such experimental results requires inverse analysis based on numerical models providing accurate and fast computation. Similar requirements apply to simulation of the integrated casting and rolling process of semi-solid steel in a sequence of passes. This problem is the main subject of the current paper. Some globally unique example results of the analysis are presented, as well.

G?owacki, Miros?aw; Debi?ski, Tomasz; Olejarczyk-Wo?e?ska, Izabela

2013-10-01

330

Effect of constituent phase on mechanical properties of 9Cr-1WVTa reduced activation ferritic-martensitic steels  

NASA Astrophysics Data System (ADS)

Influence of the formation of ferrite and accompanying carbides in martensite matrix on the tensile and Charpy impact properties was investigated for reduced activation ferritic-martensitic (RAFM) 9Cr-1WVTa steel. As the fractions of ferrite and carbide adjacent to the ferrite grain boundary increase, both tensile and Charpy impact properties deteriorated in as-normalized condition. In particular, the tensile strength and elongation decreased simultaneously, which is believed to be led by the localized deformation in ferrite which is softer than martensite, promoting the formation and growth of voids. In addition, the formation of ferrite was also detrimental to the Charpy impact properties regarding to the absorbed energy because the precipitation of carbides around ferrite were vulnerable to the nucleation and propagation of cleavage cracks. The degradation of tensile properties can be recovered by tempering, but the DBTT temperature still increases with presence of ferrite.

Lee, Chang-Hoon; Moon, Joonoh; Park, Min-Gu; Lee, Tae-Ho; Jang, Min-Ho; Kim, Hyoung Chan; Suh, Dong-Woo

2014-12-01

331

Comparison of the tribological properties at 25 C of seven different polyimide films bonded to 301 stainless steel  

NASA Technical Reports Server (NTRS)

A pin-on-disk type of friction and wear apparatus was used to study the tribological properties of seven different polyimide films bonded to AISI 301 stainless steel disks at 25 C. It was found that the substrate material was extremely influential in determining the lubricating ability of the polyimide films. All seven films spalled in less than 1000 cycles of sliding. This was believed to be caused by poor adherence to the 301 stainless steel or the inability of the films to withstand the high localized tensile stresses imparted by the deformation of the soft substrate under sliding conditions. The friction coefficients obtained for six of the polyimides varied between 0.21 to 0.32 while one varied between 0.32 to 0.39.

Fusaro, R. L.

1980-01-01

332

Influence of inclusion characteristics on the formability and toughness properties of a hot-rolled deep-drawing quality steel  

NASA Astrophysics Data System (ADS)

In industrial practice, variations in the steelmaking process may cause significant change in inclusion characteristics. During hot rolling of flat steel products, manganese sulfides, which are plastic at elevated temperatures, are elongated in the rolling direction. These elongated inclusions affect the formability properties, such as ductility, strain hardening exponent, average plastic strain ratio, critical strain represented by the forming limit diagram, and Charpy V- notch (CVN) impact energy as well as fracture behavior. The inclusion characteristics and microstructural features of three commercially produced hot- rolled deep- drawing quality steels were evaluated and their effects on formability and impact properties were investigated. All three heats were made in a basic oxygen furnace. Two heats were teemed into ingots while the other heat was argon purged and continuous cast. These heats were then processed into 3.10 mm thick strips with identical processing parameters. Manganese sulfide stringers were found to reduce the transverse ductility, whereas yield and tensile strengths remained virtually the same in all directions. The formability parameters were not significantly affected by small variations in inclusion characteristics. However, CVN impact energy and impact transition temperature data were observed to improve with steel cleanliness. The sulfide stringers were also found to adversely affect the impact energy, transition temperature, and fracture behavior in the transverse direction.

Paul, S. K.; Ray, A.

1997-02-01

333

Nondestructive evaluation of low carbon steel by magnetic adaptive testing  

Microsoft Academic Search

Three series of low carbon steel samples, plastically deformed by cold rolling to five consecutive stages of deformation, were investigated by the method of magnetic adaptive testing (MAT), typical by its low required magnetisation of samples. Samples in one series were magnetically closed; those in the other two series were magnetically open. Results of the nondestructive magnetic tests were compared

Gabor Vertesy; Ivan Tomas; Satoru Kobayashi

2010-01-01

334

Nanoscale precipitation in a maraging steel studied by APFIM.  

PubMed

This article summarizes findings from our previous investigations and recent studies concerning precipitation in a maraging steel of type 13Cr-9Ni-2Mo-2Cu (at.%) with small additions of Ti (1 at.%) and Al (0.7 at.%). The material was investigated after aging at 475 degrees C up to 400 h using both conventional and three-dimensional atom-probe analyses. The process of phase decomposition in the steel proved to be complicated. It consisted of precipitation of several phases with different chemistry. A Cu-rich phase was first to precipitate and Mo was last in the precipitation sequence. The influence of the complex precipitation path on the material properties is discussed. The investigation clearly demonstrated the usefulness of the applied techniques for investigation of nanoscale precipitation. It is also shown that, complementary methods (such as TEM and EFTEM) giving structural and chemical information on a larger scale must be applied to explain the good properties of the steel after prolonged aging. PMID:15233852

Stiller, Krystyna; Httestrand, Mats

2004-06-01

335

Nanoscale Precipitation in a Maraging Steel Studied by APFIM  

NASA Astrophysics Data System (ADS)

This article summarizes findings from our previous investigations and recent studies concerning precipitation in a maraging steel of type 13Cr-9Ni-2Mo-2Cu (at.%) with small additions of Ti (1 at.%) and Al (0.7 at.%). The material was investigated after aging at 475C up to 400 h using both conventional and three-dimensional atom-probe analyses. The process of phase decomposition in the steel proved to be complicated. It consisted of precipitation of several phases with different chemistry. A Cu-rich phase was first to precipitate and Mo was last in the precipitation sequence. The influence of the complex precipitation path on the material properties is discussed. The investigation clearly demonstrated the usefulness of the applied techniques for investigation of nanoscale precipitation. It is also shown that, complementary methods (such as TEM and EFTEM) giving structural and chemical information on a larger scale must be applied to explain the good properties of the steel after prolonged aging.

Stiller, Krystyna; Httestrand, Mats

2004-06-01

336

The improvement of weathering resistance by increasing P contents in cast strips of low carbon steels  

Microsoft Academic Search

Cast strips of low carbon steels with different P contents (0.08, 0.15, and 0.26wt%) were fabricated by using a pilot twin roll strip caster, whose mechanical properties were measured to be as good as those of the conventional counterparts. The weathering resistance of cast strips was assessed by the dry and wet cyclic accelerated corrosion test with the corrosive reagent

G. P. Zhou; Z. Y. Liu; Y. Q. Qiu; G. D. Wang

2009-01-01

337

Structure formation in a nitrogen-bearing steel under thermodeformation conditions and its relation to the mechanical properties  

NASA Astrophysics Data System (ADS)

The results of modeling thermomechanical treatment regimes for a nitrogen-containing austenitic steel using a Gleeble-3800 plastometer are presented. These results are used to recommend technological regimes for commercial implementation. The structure formed during thermomechanical treatment and the mechanical properties of a nitrogen-containing sheet steel are analyzed.

Malyshevskii, V. A.; Kalinin, G. Yu.; Fomina, O. V.; Vikhareva, T. V.; Kruglova, A. A.

2014-12-01

338

Influence of the plastic-deformation temperature on the structure and properties of low-carbon pipe steel  

Microsoft Academic Search

21 Controlled rolling is widely used to strengthen flat sheet made of lowarbon pipe steel. The structure and hence the properties depend not only on the tem? perature and deformation in rolling but also on the cooling after deformation (1, 2). In the case of air cooling, the pipe steel will predominantly contain the products of diffusional transformation of supercooled

I. Yu. Pyshmintsev; A. N. Boryakova; M. A. Smirnov; V. I. Krainov

2010-01-01

339

Perfluorocarbon thin films and polymer brushes on stainless steel 316L for control of interfacial properties  

PubMed Central

Perfluorocarbon thin films and polymer brushes were formed on stainless steel 316L (SS316L) to control the surface properties of the metal oxide. Substrates modified with the films were characterized using diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), contact angle analysis, atomic force microscopy (AFM), and cyclic voltammetry (CV). Perfluorooctadecanoic acid (PFOA) was used to form thin films by self-assembly on the surface of SS316L. Polypentafluorostyrene (PFS) polymer brushes were formed by surface initiated polymerization using SAMs of 16-phosphonohexadecanoic acid (COOH-PA) as the base. PFOA and PFS were effective in significantly reducing the surface energy and thus the interfacial wetting properties of SS316L. The SS316L control exhibited a surface energy of 38 mN/m compared to PFOA and PFS modifications, which had surface energies of 22 and 24 mN/m, respectively. PFOA thin films were more effective in reducing the surface energy of the SS316L compared to PFS polymer brushes. This is attributed to the ordered PFOA film presenting aligned CF3 terminal groups. However, PFS polymer brushes were more effective in providing corrosion protection. These low energy surfaces could be used to provide a hydrophobic barrier that inhibits corrosion of the SS316L metal oxide surface. PMID:21631123

Kruszewski, Kristen M.

2011-01-01

340

Microstructure and Properties of SAE 2205 Stainless Steel After Salt Bath Nitrocarburizing at 450 C  

NASA Astrophysics Data System (ADS)

Nitrocarburizing of the type SAE 2205 duplex stainless steel was conducted at 450 C, using a type of salt bath chemical surface treatment, and the microstructure and properties of the nitrided surface were systematically researched. Experimental results revealed that a modified layer transformed on the surface of samples with the thickness ranging from 3 to 28 ?m changed with the treatment time. After 2205 duplex stainless steel was subjected to salt bath nitriding at 450 C for time less than 8 h, the preexisting ferrite zone in the surface transformed into austenite by active nitrogen diffusion. The main phase of the nitrided layer was the expanded austenite. When the treatment time was extended to 16 h, the preexisting ferrite zone in the expanded austenite was decomposed and transformed partially into ?-nitride precipitate. When the treatment time extended to 40 h, the preexisting ferrite zone in the expanded austenite was transformed into ?-nitride and CrN precipitate. Further, a large amount of nitride precipitated from preexisting austenite zone. The nitrided layer depth thickness changed intensively with the increasing nitriding time. The growth of the nitride layer takes place mainly by nitrogen diffusion according to the expected parabolic rate law. The salt bath nitriding can effectively improve the surface hardness. The maximum values measured from the treated surface are observed to be approximately 1400 HV0.1 after 8 h, which is about 3.5 times as hard as the untreated material (396 HV0.1). Low-temperature nitriding can improve the erosion/corrosion resistance. After nitriding for 4 h, the sample has the best corrosion resistance.

Yan, Jing; Wang, Jun; Lin, Yuanhua; Gu, Tan; Zeng, Dezhi; Huang, Runbo; Ji, Xiong; Fan, Hongyuan

2014-04-01

341

Corrosion protection by sonoelectrodeposited organic films on zinc coated steel.  

PubMed

A variety of coatings based on electrosynthesized polypyrrole were deposited on zinc coated steel in presence or absence of ultrasound, and studied in terms of corrosion protection. Cr III and Cr VI commercial passivation were used as references. Depth profiling showed a homogeneous deposit for Cr III, while SEM imaging revealed good surface homogeneity for Cr VI layers. These chromium-based passivations ensured good protection against corrosion. Polypyrrole (PPy) was also electrochemically deposited on zinc coated steel with and without high frequency ultrasound irradiation in aqueous sodium tartrate-molybdate solution. Such PPy coatings act as a physical barrier against corrosive species. PPy electrosynthesized in silent conditions exhibits similar properties to Cr VI passivation with respect to corrosion protection. Ultrasound leads to more compact and more homogeneous surface structures for PPy, as well as to more homogeneous distribution of doping molybdate anions within the film. Far better corrosion protection is exhibited for such sonicated films. PMID:22516111

Et Taouil, Abdeslam; Mahmoud, Mahmoud Mourad; Lallemand, Fabrice; Lallemand, Sverine; Gigandet, Marie-Pierre; Hihn, Jean-Yves

2012-11-01

342

On the influence of surfactant over friction properties of steel  

NASA Astrophysics Data System (ADS)

Surfactant wetting properties are important for any tribological system. In order to explore these properties the influence of four surfactant i.e. sodium hexametaphosphate (SHMP); zinc dithiodiphosphate (ZDDP); sodium dodecyl sulphate (SDS); and cetrimonium bromide (C-TAB); on the friction behaviour of physical vapour deposition (PVD) coated surfaces were studied using pin on disk tribometer. Anionic, cationic and non-ionic surfactants are dispersed in oil/water medium. Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and X-ray diffraction (XRD) analysis was performed to obtain the surface morphology, chemical composition and structure of the material.

Upadhyay, R. K.; Kumaraswamidhas, L. A.

2014-07-01

343

The effect of high pressure torsion on structural refinement and mechanical properties of an austenitic stainless steel.  

PubMed

In the present study, the high pressure torsion (HPT) was used to refine the grain structure down to the nanometer scale in an austenitic stainless steel. The principles of HPT lay on torsional deformation under simultaneous high pressure of the specimen, which results in substantial reduction in the grain size. Disks of the 316LVM austenitic stainless steel of 10 mm in diameter were subjected to equivalent strains epsilon of 32 at RT and 450 degrees C under the pressure of 4 GPa. Furthermore, two-stage HPT processes, i.e., deformation at room temperature followed by deformation at 450 degrees C, were performed. The resulting microstructures were investigated in TEM observations. The mechanical properties were measured in terms of the microhardness and in tensile tests. HPT performed at two-stage conditions (firstly at RT next at 450 degrees C) gives similar values of microhardness to the ones obtained after deforming only at 450 degrees C but performed to higher values of the overall equivalent strain epsilon. The effect of high pressure torsion on structural refinement and mechanical properties of an austenitic stainless steel was evaluated. PMID:23858838

Krawczynska, Agnieszka Teresa; Lewandowska, Malgorzata; Pippan, Reinhard; Kurzydlowski, Krzysztof Jan

2013-05-01

344

Titanium Nitride Coatings Prepared by Reactive Sputtering on Steel  

NASA Astrophysics Data System (ADS)

Titanium nitride is used as coating on cutting tools because of their excellent mechanical properties such as high hardness and high wear resistance. Its chemical inertness gives rise to its application as corrosion protective coating. It's an excellent barrier material with good electrical conductivity in various metallization structures of advanced microelectronic devices. Finally, the golden glance of TiN established its use as decorative coating in the fashion jewellery and in architecture. The deposition process studied, in this work, use RF sputtering of a pure titanium target in a reactive nitrogen/ argon gas mixture, at various conditions. The substrates are steel. The main variables investigated are the composition of the Ar/N2 gas mixture, the total pressure, the deposition time and the discharge power. The aim of this work is to evaluate the performances of a local-made RF plasma reactor. The attention was given to the study of the structure, the composition of titanium nitride deposits, which have a considerable influence on their hardness. The deposited coatings were characterized by X-ray diffraction, energy dispersive spectroscopy (EDS) and micro-indentation.

Nadia, Saoula; Karim, Henda; Rafika, Kesri

2007-10-01

345

Comparative studies on shielding properties of some steel alloys using Geant4, MCNP, WinXCOM and experimental results  

NASA Astrophysics Data System (ADS)

The mass attenuation coefficients, ?/? and effective atomic numbers, Zeff of some carbon steel and stainless steel alloys have been calculated by using Geant4, MCNP simulation codes for different gamma ray energies, 279.1 keV, 661.6 keV, 662 keV, 1115.5 keV, 1173 keV and 1332 keV. The simulation results of Zeff using Geant4 and MCNP codes have been compared with possible available experimental results and theoretical WinXcom, and good agreement has been observed. The simulated ?/? and Zeff values using Geant4 and MCNP code signifies that both the simulation process can be followed to determine the gamma ray interaction properties of the alloys for energies wherever analogous experimental results may not be available. This kind of studies can be used for various applications such as for radiation dosimetry, medical and radiation shielding.

Singh, Vishwanath P.; Medhat, M. E.; Shirmardi, S. P.

2015-01-01

346

Effect of heat treatment on the mechanical properties of modified 9Cr-1Mo steel  

SciTech Connect

The modified 9Cr-1Mo steel (Grade 91) is a material of choice in fossil-fuel-fired power plants with increased efficiency, service life, and reduction in emission of greenhouse gases. It is also considered a prospective material for the Next Generation Nuclear Power Plant for application in reactor pressure vessels at temperatures up to 650C. In this paper, heat treatment of the modified 9Cr-1Mo steel was studied by normalizing and tempering the steel at various temperatures and times, with the ultimate goal of improving its creep resistance and optimizing material hardness. The microstructural evolution of the heat treated steels was correlated with the differential scanning calorimetric results. Optical microscopy, scanning and transmission electron microscopy in conjunction with microhardness profiles and calorimetric plots were used to understand the evolution of microstructure including precipitate structures in modified 9Cr-1Mo steel and relate it to the mechanical behavior of the steel. Thermo- CalcTM calculations were used to support experimental work and provide guidance in terms of the precipitate stability and microstructural evolution. Furthermore, the carbon isopleth and temperature dependencies of the volume fraction of different precipitates were constructed. The predicted and experimentally observed results were found to be in good agreement.

Sultan F. Alsagabi; Triratna Shrestha; Indrajit Charit; Gabriel P. Potirniche; Michael V. Glazoff

2014-09-01

347

Thermal and Tribological Analysis of the Dry Sliding Steel-steel Couple Traversed by an Electrical Current  

NASA Astrophysics Data System (ADS)

This study concerns a thermal and tribological analysis of the dry sliding steel-steel couple traversed by an electrical current. The tests were carried out by using a tribometer pin-disc under ambient air environment. The dry friction and wear of this contact are studied with different parameters such as normal load, electrical current and sliding speed (maintained constant V = 0.5 m/s). The test duration is 20 mn. The experimental results obtained show that these parameters have a more or less significant effect on the tribological behavior of the couple. Indeed, the oxidation phenomenon, the particles of wear resulting from this oxidation, their composition, their morphology and their thermal-mechanical properties, under certain conditions, play an important role and determine the life service of this couple. To highlight the effect of these parameters, theoretical calculations based on the theories of Archard and Holm have been done. These calculations allowed us to evaluate the order of magnitude of the mechanical, geometrical, thermal and electrical parameters. The discussion of the results is mainly based on these calculations, optical and SEM observations as well as other phenomena resulting from the friction process.

Boubechou, C.; Bouchoucha, A.; Zaidi, H.; Mouadji, Y.

348

First principles modeling of structure and properties of multi-component amorphous steels  

NASA Astrophysics Data System (ADS)

Amorphous steels (iron based metallic glasses) exhibit unique physical properties that have opened the venue to new commercial applications as well as renewed the interest in this field. To provide a realistic description of the three dimensional structures and associate the coordinated environment of atoms to physical properties, first principles quantum mechanical molecular dynamics (MD) simulations along with the pair density function (PDF) analysis of neutron and X-ray diffraction data were used by way of considering chemical effects, ionic size ratio and concentration. Direct comparison of the simulated atomic structures obtained from MD with the local atomic structures determined experimentally show a very good agreement between the two, indicating that this theoretical approach can be applied towards simulating multi-component alloys. The atomic coordinates were used to develop the building blocks of cluster-like structures that give rise to the short-range order. The diffusion rates of different atom species were modeled at several temperatures that allowed us to describe the quenching process. In addition, the bulk moduli as a function of chemical composition were simulated and showed a very good agreement with the ones obtained experimentally.

Kazimirov, Viatcheslav; Louca, Despina; Widom, Michael

2008-03-01

349

Evaluation of microstructure and mechanical properties in friction stir processed SKD61 tool steel  

SciTech Connect

A SKD61 tool steel was friction stir processed using a polycrystalline cubic boron nitride tool. Microstructure, tensile properties and wear characteristic were evaluated. Fine grains with a martensite structure were produced in the friction stir processed zone, which led to the increase of the microindentation hardness. The grains became finer when the heat input was lowered. The transverse tensile strength of the friction stir processed zone was equal to that of base metal and all the tensile specimens fractured at base metal zone. The wear width and depth of the friction stir processed zone at the load of 1.96 N were 339 {mu}m and 6 {mu}m, as compared to 888 {mu}m and 42 {mu}m of the base metal, decreased by 62% and 86%. Findings of the present study suggest that low heat input is an effective method to produce a friction stir processed zone composed of relatively fine grain martensitic structure with good tensile properties and wear characteristic.

Chen, Y.C., E-mail: armstrong@hit.edu.cn [Joining and Welding Research Institute, Osaka University, Osaka 567-0047 (Japan); Nakata, K. [Joining and Welding Research Institute, Osaka University, Osaka 567-0047 (Japan)

2009-12-15

350

Easy-to-clean property and durability of superhydrophobic flaky ?-alumina coating on stainless steel in field test at a paper machine  

NASA Astrophysics Data System (ADS)

Superhydrophobic flaky ?-alumina coating was prepared on AISI 316 2B stainless steel and was field-tested near size roll at a paper machine in a paper mill for 6 weeks consisting of two running periods of machine to check the easy-to-clean property and durability, as compared to an uncoated reference stainless steel. In the end of the field test, both the superhydrophobic and the reference stainless steel were fully covered with substances from the testing environment. Major part of the collected substances on the superhydrophobic stainless steel can be washed away by pressurized water; however, the collected substances remained on the reference stainless steel after washing. The field-tested samples were characterized visually and by stereomicroscopy, field emission scanning electron microscopy, laser profilometry and contact angle tester. The field test revealed the easy-to-clean property of the superhydrophobic surface and the superhydrophobic coating survived rather well after the first running period of 16 days in the field test. The resistance and durability of the superhydrophobic surface still needs to be further improved for longer term application in paper industry. Nanoindentation was used to further study the mechanical properties of the ?-alumina coating. It was found that the ?-alumina coating became much softer after transforming from flat to flaky form. In addition, the flaky ?-alumina coating demonstrated a phenomenon of time-dependent plasticity and some flexibility.

Zhang, Xiaoxue; Liu, Xuwen; Laakso, Jarmo; Levnen, Erkki; Mntyl, Tapio

2012-01-01

351

Interaction of Benzimidazoles and Benzotriazole: Its Corrosion Protection Properties on Mild Steel in Hydrochloric Acid  

NASA Astrophysics Data System (ADS)

Synergistic hydrogen-bonded interaction of alkyl benzimidazoles and 1,2,3-benzotrizole and its corrosion protection properties on mild steel in hydrochloric acid at different temperatures have been studied using polarization, EIS, adsorption, surface studies, and computational methods. The extent of synergistic interaction increases with temperature. Quantum chemical approach is used to calculate some electronic properties of the molecules and to ascertain the synergistic interaction, inhibitive effect, and molecular structures. The corrosion inhibition efficiencies and the global chemical reactivity relate to some parameters, such as total energy, E HOMO, E LUMO, and gap energy (? E). 1,2,3-Benzotrizole interacts with benzimidazoles derivatives up to a bond length of approximately 1.99 . This interaction represents the formation of a hydrogen bond between the 1,2,3-benzotrizole and benzimidazoles. This synergistic interaction of 1,2,3-benzotrizole and benzimidazole derivatives offers extended inhibition efficiency toward mild steel in hydrochloric acid.

Ramya, K.; Mohan, Revathi; Joseph, Abraham

2014-11-01

352

Surface modification of superaustenitic and maraging stainless steels by low-temperature gas-phase carburization  

Microsoft Academic Search

Low-temperature gas-phase carburization of 316L austenitic stainless steel was developed in recent years by the Swagelok company. This process generates great mechanical and electrochemical surface properties. Hardness, wear resistance, fatigue behavior, and corrosion resistance are dramatically improved, while the formation of carbides is effectively suppressed. This new technique is of technical, economical, but especially of scientific interest because the surface

Johannes Gentil

2008-01-01

353

Improvement of the forgability of 17-4 precipitation hardening stainless steel by ausforming  

Microsoft Academic Search

The ausforming process for 17-4 precipitation hardening (17-4PH) stainless steel is compared with the conventional warm-forging process, from the point of both the forgeability and the properties of the forged material. The forgeability is evaluated by upsetting, forward rod extrusion and backward can extrusion. The forging force required in ausforming is about half that required in conventional warm-forging: it especially

Sachihiro Isogawa; Hiroaki Yoshida; Yuzo Hosoi; Yasuhisa Tozawa

1998-01-01

354

Effect of heat treatment on the structure and properties of cast steel shot  

Microsoft Academic Search

The structure and properties of steel shot in cast and heat-treated (quenching and tempering) states are investigated. Shot\\u000a of three size groups (fine, medium, and course with a mean size of 0.5, 2.0, and 3.6 mm, respectively) is studied. Metallographic\\u000a analysis and compressive strength tests with determination of the value of the breaking load are performed. The microhardness\\u000a of the

S. V. Grachev; L. A. Maltseva; O. V. Zhuikov; V. P. Gvozdovskii; S. N. Shlyapnikov; A. F. Emelyanov

2006-01-01

355

Tensile properties of 0.05 to 0.20 Pct C TRIP steels  

Microsoft Academic Search

The uniaxial tensile properties of a series of TRIP steels of varying carbon contents and processing histories were determined\\u000a over a wide range of test temperatures. The yield strengths at room temperature varied both with the deformation temperature\\u000a (over the range 250 to 550C) and with the carbon content (0.05 to 0.20 pct). Possible reasons for these variations are advanced.

G. R. Chanani; V. F. Zackay; Earl R. Parker

1971-01-01

356

Correlation of microstructure and thermal-fatigue properties of centrifugally cast high-speed steel rolls  

Microsoft Academic Search

This is a study of thermal-fatigue properties in centrifugally cast high-speed steel (HSS) rolls. The thermal-fatigue mechanism\\u000a was investigated, with special focus on the roll microstructure and the increase in tensile stress which led the specimens\\u000a to fracture when it reached the tensile strength. The thermal-fatigue test results indicated that the thermal-fatigue life\\u000a decreased with increasing maximum temperature of the

Chang Kyu Kim; Jong Il Park; Jae Hwa Ryu; Sunghak Lee

2004-01-01

357

Microstructure and mechanical properties of the TIG welded joints of fusion CLAM steel  

Microsoft Academic Search

The CLAM steel plates were butt-welded through manual tungsten inert gas welding (TIG) process, and the following post-welding heat treatment (PWHT) at 740C for 1h. The microstructure and mechanical properties of the welded joints were measured. The results show that both hardening and softening occur in the weld joints before PWHT, but the hardening is not removed completely in the

Zhizhong Jiang; Litian Ren; Jihua Huang; Xin Ju; Huibin Wu; Qunying Huang; Yican Wu

2010-01-01

358

Tensile and fatigue properties of 17-4 PH stainless steel at high temperatures  

Microsoft Academic Search

The tensile and high-cycle fatigue properties for 17-4 PH* stainless steels in three different conditions were investigated\\u000a at temperatures ranging from room temperature to 400 C. Results indicated that the yield strength and fatigue strength for\\u000a the three conditions at a given temperature took the following order: condition H900 > condition A> condition H1150. The yield\\u000a strength of each condition

Jui-Hung Wu; Chih-Kuang Lin

2002-01-01

359

Tensile Properties and Work Hardening Behavior of Laser-Welded Dual-Phase Steel Joints  

Microsoft Academic Search

The aim of this investigation was to evaluate the microstructural change after laser welding and its effect on the tensile\\u000a properties and strain hardening behavior of DP600 and DP980 dual-phase steels. Laser welding led to the formation of martensite\\u000a and significant hardness rise in the fusion zone because of the fast cooling, but the presence of a soft zone in

N. Farabi; D. L. Chen; Y. Zhou

2011-01-01

360

Structure and properties of high-strength corrosion-resistant silicon-alloyed sheet steel  

Microsoft Academic Search

1.In order to ensure suitability for industrial processes in production of sheet metal and sheet constructions of steel of the martensitic class and the required combination of mechanical properties and resistance to corrosion action, it is necessary to regulate the phase composition (s-Fe content in the weld and castings 38%, amount of residual austenite 820%) upon alloying the carbon-free Cr-Ni

A. G. Bratukhin; A. F. Petrakov; G. S. Krivonogov; L. Ya. Gurvich

1993-01-01

361

Weld microstructure development and properties of precipitation-strengthened martensitic stainless steels  

Microsoft Academic Search

The weld microstructural evolution, mechanical properties and solidification cracking susceptibility of three precipitation-strengthened martensitic stainless steels--PH 13-8 Mo, Custom 450 and 15-5 PH--were investigated. Liquid tin quenching of gas tungsten arc welds revealed that all three welds solidified as single-phase ferrite with a high degree of microsegregation. However, during further solidification and cooling almost complete homogenization occurred as a result

J. A. Brooks; W. R. Jr. Garrison

1999-01-01

362

Effects of laser power density on static and dynamic mechanical properties of dissimilar stainless steel welded joints  

NASA Astrophysics Data System (ADS)

The mechanical properties of laser welded joints under impact loadings such as explosion and car crash etc. are critical for the engineering designs. The hardness, static and dynamic mechanical properties of AISI304 and AISI316 L dissimilar stainless steel welded joints by CO2 laser were experimentally studied. The dynamic strain-stress curves at the strain rate around 103 s-1 were obtained by the split Hopkinson tensile bar (SHTB). The static mechanical properties of the welded joints have little changes with the laser power density and all fracture occurs at 316 L side. However, the strain rate sensitivity has a strong dependence on laser power density. The value of strain rate factor decreases with the increase of laser power density. The welded joint which may be applied for the impact loading can be obtained by reducing the laser power density in the case of welding quality assurance.

Wei, Yan-Peng; Li, Mao-Hui; Yu, Gang; Wu, Xian-Qian; Huang, Chen-Guang; Duan, Zhu-Ping

2012-10-01

363

A critical assessment of the hardening of steel by martempering  

Microsoft Academic Search

Martempering is well established as a method by which the stresses and strains generated during the quenching of a steel component may be controlled. In this process the component is held at an intermediate temperature in a salt bath subsequent to the initial cooling from the austenitization temperature, but prior to the final quench to ambient. This allows sufficient time

F. ABBASI; A. J. FLETCHER; A. B. SOOMRO

1987-01-01

364

Particles into 410L Stainless Steel by a Powder Metallurgy Route  

NASA Astrophysics Data System (ADS)

Addition of yttria to steels has been proposed for the fabrication of oxide-dispersion-strengthened materials for nuclear power applications. We have investigated materials prepared from 12 Cr martensitic stainless steel, AISI 410L, produced by powder metallurgy. Materials were produced with and without yttria addition, and two different sizes of yttria were used, 0.9 m and 50 nm. Tensile and mini-creep tests were performed to determine mechanical properties. Optical microscopy, SEM, TEM, and EDX analysis were used to investigate the microstructures and deformation mechanisms and to obtain information about non-metallic inclusion particles. SiO2, MnS, and Y2Si2O7 inclusion particles were observed. An SiO2 and Y2O3 interaction was seen to have occurred during the ball milling, which impaired the final mechanical properties. Small-angle neutron scattering experiments showed that the matrix chemistry prevented effective dissolution of the yttria.

Zeybek, A.; Barroso, S. Pirfo; Chong, K. B.; Edwards, L.; Fitzpatrick, M. E.

2014-06-01

365

Effect of Grain Refinement on the Mechanical Properties of a Nickel- and Manganese-Free High Nitrogen Austenitic Stainless Steel  

NASA Astrophysics Data System (ADS)

Grain coarsening due to the high temperature exposure deteriorates mechanical properties of the high nitrogen austenitic stainless steels (HNASSs) produced by solution nitriding. To improve mechanical properties, the grains of nickel and manganese-free Fe-23Cr-2.4Mo-1.2N HNASS plates fabricated by pressurized solution nitriding were refined using a two-stage heat treatment process. Structural and mechanical properties were investigated using X-ray diffraction, optical microscopy, scanning and transmission electron microscopy, hardness and tensile testing and compared with that of the conventional AISI 316L steel. The results show that the as-produced HNASS exhibits uniform deformation up to failure without necking and brittle inter-granular fracture. By grain refinement, the yield and tensile strengths as well as the elongation to failure are increased by 17.8, 21.2, and 108.3 pct, respectively, as compared to the as-produced HNASS. However, despite more than a double increase in tensile toughness and elongation to failure, the brittle inter-granular fracture is not suppressed. The HNASSs plastically deform through formation of straight slip bands. TEM observations indicate development of planar arrays of dislocations in tensile-deformed HNASSs. The enhancement in tensile strength and toughness by grain refinement is discussed on the basis of straight slip bands formation, number of dislocations in pile-ups, and incompatibility strain developed between adjacent grains.

Akbari, Alireza; Mohammadzadeh, Roghayeh

2015-04-01

366

Effect of Grain Refinement on the Mechanical Properties of a Nickel- and Manganese-Free High Nitrogen Austenitic Stainless Steel  

NASA Astrophysics Data System (ADS)

Grain coarsening due to the high temperature exposure deteriorates mechanical properties of the high nitrogen austenitic stainless steels (HNASSs) produced by solution nitriding. To improve mechanical properties, the grains of nickel and manganese-free Fe-23Cr-2.4Mo-1.2N HNASS plates fabricated by pressurized solution nitriding were refined using a two-stage heat treatment process. Structural and mechanical properties were investigated using X-ray diffraction, optical microscopy, scanning and transmission electron microscopy, hardness and tensile testing and compared with that of the conventional AISI 316L steel. The results show that the as-produced HNASS exhibits uniform deformation up to failure without necking and brittle inter-granular fracture. By grain refinement, the yield and tensile strengths as well as the elongation to failure are increased by 17.8, 21.2, and 108.3 pct, respectively, as compared to the as-produced HNASS. However, despite more than a double increase in tensile toughness and elongation to failure, the brittle inter-granular fracture is not suppressed. The HNASSs plastically deform through formation of straight slip bands. TEM observations indicate development of planar arrays of dislocations in tensile-deformed HNASSs. The enhancement in tensile strength and toughness by grain refinement is discussed on the basis of straight slip bands formation, number of dislocations in pile-ups, and incompatibility strain developed between adjacent grains.

Akbari, Alireza; Mohammadzadeh, Roghayeh

2015-01-01

367

Weldability, microstructure and properties of precipitation strenghtened martensitic stainless steels. [Custom 450; PH 13-8 Mo  

SciTech Connect

We have investigated the influence of welding on the mechanical properties and corrosion resistance of two precipitation strengthened martensitic stainless steels: Custom 450 and PH 13-8 Mo. The two alloys exhibited very good weld cracking resistance, although the formation of a low melting NbC eutectic constituent did cause some solidification cracking in Custom 450. The effects of aging temperature on tensile and impact properties were similar in the base metal and Gas-Tungsten-Arc (GTA) weldment for both alloys. The similarity of weld and base metal properties is attributed to the uniform precipitate distribution throughout the weld, as shown by Transmission Electron Microscopy (TEM) and electron microprobe analyses. The susceptibility to pitting corrosion was not impaired by aging or by welding, with the possible exception of a narrow band in the heat-affected zone (HAZ), and both materials were more resistant than 304 stainless steel. The narrow band is identified by electrochemical reactivation testing as a region of increased matrix activity likely caused by localized Cr and/or Mo depletion.

Brooks, J.A.; Cieslak, W.R.; Garrison, W.M. Jr.

1986-01-01

368

Natural and synthetic rubber coatings for steel: Properties and compositions. (Latest citations from World Surface Coatings abstracts). Published Search  

SciTech Connect

The bibliography contains citations concerning the application of compositions containing natural and synthetic rubbers to steel. Polyurethane elastomers, chlorinated rubber coatings, and rubber containing acrylic adhesives are among the coatings discussed. Studies of the degradation of rubber coatings applied to steel are included. Bonding properties, adhesion strength, weathering, and anticorrosive properties are discussed. Additional information on anticorrosive coatings may be found in other bibliographies. (Contains a minimum of 180 citations and includes a subject term index and title list.)

Not Available

1994-04-01

369

Development of low-temperature high-strength integral steel castings for offshore construction by casting process engineering  

NASA Astrophysics Data System (ADS)

In casting steels for offshore construction, manufacturing integral casted structures to prevent fatigue cracks in the stress raisers is superior to using welded structures. Here, mold design and casting analysis were conducted for integral casting steel. The laminar flow of molten metal was analyzed and distributions of hot spots and porosities were studied. A prototype was subsequently produced, and air vents were designed to improve the surface defects caused by the release of gas. A radiographic test revealed no internal defects inside the casted steel. Evaluating the chemical and mechanical properties of specimens sampled from the product revealed that target values were quantitatively satisfied. To assess weldability in consideration of repair welding, the product was machined with grooves and welded, after which the mechanical properties of hardness as well as tensile, impact, and bending strengths were evaluated. No substantive differences were found in the mechanical properties before and after welding.

Lim, Sang-Sub; Mun, Jae-Chul; Kim, Tae-Won; Kang, Chung-Gil

2014-12-01

370

Prior thermo-mechanical processing to modify structure and properties of severely deformed low carbon steel  

NASA Astrophysics Data System (ADS)

The article focuses on the severe plastic deformation (SPD) of low carbon steel AISI 1010 performed at increased temperature. The grain refinement of ferrite structure is monitored and described with respect to different initial steel structure modified by thermal and thermomechanical (TM) treatment (TM) prior severe plastic deformation. The refinement of coarse initial ferrite structure with grain size in range of 30 - 50 gm resulted from solutioning was conducted then in two steps. Preliminary structure refinement has been achieved due to multistep open die forging process and quite uniform ferrite structure with grain size of the order of gm was obtained. The further grain refinement steel structure was then accomplished during warm Equal Channel Angular Pressing (ECAP phi = 120) at 300C, introducing different strain in range of ?ef = 2.6 -4. The change of microstructure in dependence of the effective strain was evaluated by SEM and TEM study of thin foils. The high straining of steel resulted in extensive deformation of ferrite grains and formation of mixture of submicron grains structure in banded deformed structure with dense dislocation network and subgrains. The dynamic polygonization process, due to increased ECAP temperature, modified the submicrocrystalline structure formation. There was only indistinctive difference observed in structure refinement when considering different initial structure of steel. The tensile behaviour was characterized by strength increase followed by softening. None work hardening phenomenon appeared at tensile deformation of deformed bars.

Zrnik, J.; Lapovok, R.; Raab, G. I.

2014-08-01

371

Niobium-alloyed high speed steel by powder metallurgy  

SciTech Connect

A philosophy for the use of strong carbide formers like niobium in high speed steels is described. It follows the concept of independently optimizing the compositions of the matrix (for maximum secondary hardening potential) and the volume fraction of the blocky carbides (for protection against abrasive wear). Normally, the two are interdependent through the action of the solidification equilibria, but separate control becomes possible when the blocky carbides are formed by a strong carbide former such as niobium. During normal ingot solidification, such strong carbide formers would produce very large primary carbides. This can be avoided by atomization and powder metallurgical processing. In this way, a steel has been produced whose matrix composition is similar to that of AISI M2, and whose primary carbides are all of NbC type. Its composition is 1.3C, 2W, 3Mo, 1.6V, 3.2Nb (wt pct). Because of its high stability, NbC is a much more effective obstacle to grain growth than the normal high speed steel carbides, and this allows substantially higher austenitization temperatures to be used. Despite its leaner composition, the Nb-alloyed steel matches the cutting performance of AISI M2, and its secondary hardening seems to be more persistent at high temperatures.

Karagoz, S.; Fischmeister, H.F.

1988-06-01

372

Effect of Casting Defect on Mechanical Properties of 17-4PH Stainless Steel  

NASA Astrophysics Data System (ADS)

Damage and integrity evaluation techniques should be developed steadily in order to ensure the reliability and the economic efficiency of gas turbine engines. Casting defects may exist in most casting components of gas turbine engines, and the defects could give serious effect on mechanical properties and fracture toughness. Therefore, it is very important to understand the effect of casting defects on the above properties in order to predict the safety and life of components. In this study, specimens with internal casting defects, made from 17-4PH stainless steel, were prepared and evaluated and characterized based on the volume fraction of defects. The relation between mechanical properties such as tensile, low cycle fatigue and fracture toughness and volume fraction of defect has been investigated. As a result of the analysis, the mechanical properties of 17-4PH decreased as the defect volume fraction increased with very good linearity. The mechanical properties also showed an inversely proportional relationship to electrical resistivity.

Kim, Jong-Yup; Lee, Joon-Hyun; Nahm, Seung-Hoon

373

Mechanical Properties of Laser Heat Treated 6 mm Thick UHSS-Steel  

SciTech Connect

In this work abrasion resistant (AR) steel with a sheet thickness of 6 mm was heat treated by a 4 kW Nd:YAG and a 4 kW Yb:Yag-laser, followed by self-quenching. In the delivered condition, test material blank (B27S) is water quenched from 920 deg. C. In this condition, fully martensitic microstructure provides excellent hardness of over 500 HB. The test material is referred to AR500 from now onwards. Laser heat treatment was carried out only on top surface of the AR500 sheet: the achieved maximum temperature in the cross-section varies as a function of the depth. Consequently, the microstructure and mechanical properties differ between the surfaces and the centre of the cross-section (layered microstructure). For better understanding, all layers were tested in tensile tests. For a wide heat treatment track, the laser beam was moved by scanning. Temperatures were measured using thermographic camera and thermocouples. Laser heat treated AR500 samples were tested in hardness tests and by air bending using a press brake machine. Microstructures were studied using a light microscope and FE-SEM/SEM-EBSD. At least three kind of microstructure layers were observed: 1) Dual-Phase ferritic/martensitic (T = A{sub C1}-A{sub C3}), 2) ferritic (T{approx}A{sub C3}) and 3) bainitic/martensitic (T>A{sub C3}).

Jaervenpaeae, Antti; Maentyjaervi, Kari; Maeaettae, Antti; Hietala, Mikko [University of Oulu, Oulu Southern Institute, Pajatie 5, FIN-85500 Nivala (Finland); Merklein, Marion [University of Erlangen-Nuremberg, Chair of Manufacturing Technology (Germany); Karjalainen, Jussi [University of Oulu, Department of Mechanical Engineering, P.O. BOX 4200, FIN-90014 (Finland)

2011-05-04

374

Radiation Effects in Stainless Steel and Tungsten for use in the ADS Spallation Neutron Source System  

Microsoft Academic Search

Radiation effects have been studied in modified 316L stainless steel and commercially available stainless steel and tungsten by the heavy ion irradiation simulation and positron lifetime techniques. The experimental results show that the radiation resistant property of stainless steel is much better than that of tungsten, and the modified 316L stainless steel is the best among them. The stainless steel

Yongjun Xu; Zhiqiang Wang; Jiazheng Zhu; T. Minamisono; K. Matsuta; Yongnan Zheng; Dongmei Zhou; Guoji Xu; Enpeng Du; Youlin Fu; M. Fukuda; M. Mihara; Shengyun Zhu

2003-01-01

375

The Effects of Cooling Mode on Precipitation and Mechanical Properties of a Ti-Nb Microalloyed Steel  

NASA Astrophysics Data System (ADS)

Laboratory experiments of a high-strength Ti-Nb microalloyed steel were conducted with two cooling modes, i.e., a large (35 C s-1) cooling rate in the initial stage followed by slow (8.5 C s-1) cooling rate (termed as FFC) and a slow (8.5 C s-1) cooling rate in the initial stage followed by large (35 C s-1) cooling rate (LFC) during cooling process. Based on the results of laboratory experiments, an industrial trial was performed with similar steel on a continuous hot strip production mill. The grain size in LFC sample (2.83 ?m) is smaller than that in FFC sample (3.80 ?m), and the volume fraction of precipitates in LFC sample (1.04%) is more than that in FFC sample (0.81%). Both results of laboratory experiments and industrial tests confirm that the strengthening effect of the LFC mode is much better than that of the FFC mode from the viewpoints of both fine-grain strengthening and precipitation strengthening. The present study provides a new approach to improve the property of microalloyed steels produced by continuous hot rolling technology.

Hu, Zhangwei; Xu, Guang; Yang, Hailin; Zhang, Chen; Yu, Ru

2014-12-01

376

Effect of Nb and Cu on the high temperature creep properties of a high MnN austenitic stainless steel  

SciTech Connect

The effect of Nb and Cu addition on the creep properties of a high MnN austenitic stainless steel was investigated at 600 and 650 C. In the original high MnN steel, which was initially precipitate-free, the precipitation of M{sub 23}C{sub 6} (M = Cr, Fe) and Cr{sub 2}N took place mostly on grain boudaries during creep deformation. On the other hand, the minor addition of Nb resulted in high number density of Z-phases (CrNbN) and MX (M = Nb; X = C, N) carbonitrides inside grains by combining with a high content of N, while suppressing the formation of Cr{sub 2}N. The addition of Cu gave rise to the independent precipitation of nanometer-sized metallic Cu particles. The combination of the different precipitate-forming mechanisms associated with Z-phase, MX and Cu-rich precipitates turned out to improve the creep-resistance significantly. The thermodynamics and kinetics of the precipitation were discussed using thermo-kinetic simulations. - Highlights: The creep rupture life was improved by Nb and Cu addition. The creep resistance of the steel A2 in this study was comparable to that of TP347HFG. The size of Z-phase and MX carbonitride did not change significantly after creep test. The nanometer sized Cu-rich precipitate was observed after creep. The predicted size of precipitates by MatCalc agreed well with measured size.

Lee, Kyu-Ho, E-mail: kyuhos@korea.ac.kr [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Suh, Jin-Yoo, E-mail: jinyoo@kist.re.kr [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Huh, Joo-Youl, E-mail: jyhuh@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Park, Dae-Bum, E-mail: parkdaebum@gmail.com [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Hong, Sung-Min, E-mail: magerit84@gmail.com [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Shim, Jae-Hyeok, E-mail: jhshim@kist.re.kr [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Jung, Woo-Sang, E-mail: wsjung@kist.re.kr [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)

2013-09-15

377

Microstructure and property examination of the weld HAZ in Grade 100 microalloyed steel  

NASA Astrophysics Data System (ADS)

The microstructure and mechanical property variations across different regions of the heat-affected zone (HAZ) of a Grade 100 microalloyed steel were examined for a range of heat inputs from 0.5 to 2.5 kJ/mm. Autogenous gas tungsten arc welding was performed on plates of Grade 100 steel to create the HAZ. The weld thermal cycles were recorded by embedding thermocouples at different locations in the plates. Examination of precipitate alterations (dissolution, coarsening and reprecipitation) was carried out theoretically and/or experimentally using transmission electron microscopy (TEM). Iron matrix phase transformations and grain size changes were examined with optical microscopy as well as TEM (both thin foils and carbon replicas). Hardness measurements (macro-, micro- and nano-hardness) were mainly used for examination of mechanical properties across the HAZ. Hardness measurements across the HAZ showed hardening in 0.5 kJ/mm weld samples and softening in the 1.5 and 2.5 kJ/mm weld samples. This was mainly due to the difference in cooling rates, since fast cooling results in microstructures with finer structures (especially grain size) and higher levels of solutes and sub-structure in the matrix. The coarse-grained HAZ (CGHAZ) had a higher hardness relative to the fine-grained HAZ (FGHAZ), regardless of the heat input, due to the formation of bainitic and martensitic fine structures (laths/plates) inside large prior austenite grains. The CGHAZ-0.5 kJ/mm consisted of packets of untempered lath martensite and coarse regions of autotempered martensite or aged massive ferrite. Increasing the heat input to 1.5 and 2.5 kJ/mm resulted in mainly bainitic microstructures (e.g., granular bainite) with some acicular ferrite and grain-boundary ferrite in the CGHAZ. The FGHAZ was mainly made up of polygonal ferrite, with considerable amounts of bainitic ferrite in the case of the 0.5 kJ/mm weld sample. Nb-rich carbides mostly survived the thermal cycles experienced in FGHAZ, but were dissolved in the CGHAZ due to exposure to higher temperatures. Ti-rich nitrides mostly survived even in the CGHAZ, but they had limited contribution to grain growth control due to their coarse distribution in the base metal. Transformation twins were observed in some regions across the HAZ. Their formation is believed to relieve high thermal, solidification-induced and transformation-induced stresses, at places where deformation by slipping was not achievable.

Poorhaydari-Anaraki, Kioumars

378

Microstructure properties of tempered D6ac steel  

NASA Astrophysics Data System (ADS)

The aim of this study was to determine the microstructure and surface mechanical properties of tempered D6ac. The obtained microstructures exhibited a number of misfit dislocations from work hardening, with the degree of disorder dislocation decreasing gradually upon increasing the temperature at 650 C. XRD spectra observed that the residual austenite and/or mixed structures of ferrite with the precipitation of carbides at 650 C will result in a softer state than that of the room temperature specimen. In addition, the forming process has a high microhardness of martensite phase at surface layer, subjected to heat treatment until a stable state is achieved. The content of ferrite atoms decreased and that of carbon and chromium elements increased upon increasing the tempering temperature.

Lian, Derming

2013-01-01

379

Rhenium Uptake as Analogue 96Tc by Steel Corrosion Products  

SciTech Connect

Static batch experiments were used to examine the sorption of dissolved perrhenate [Re(VII)], as a surrogate for pertechnetate [Tc(VII)], on corrosion products of A-516 carbon steel coupons contacted with synthetic groundwater or dilute water. After 109 days of contact time, the concentration of dissolved Re(VII) in the synthetic groundwater matrix decreased by approximately 26%; the dilute water matrix experienced a 99% decrease in dissolved Re(VII) over the same time period. Bulk x-ray diffraction (XRD) results for the corroded steel coupons showed that the corrosion products consisted primarily of maghemite, lepidocrocite, and goethite. Analyses of the coupons by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) indicated that Re was present with the morphologically complex assemblages of Fe oxide/hydroxide corrosion products for samples spiked with the highest dissolved Re(VII) concentration (1.0 mmol/L) used for these experiments. Analyses of corroded steel coupons contacted with solutions containing 1.0 mmol/L Re(VII) by synchrotron-based methods confirmed the presence of Re sorbed with the corrosion product on the steel coupons. Analyses showed that the Re sorbed on these corroded coupons was in the +7 oxidation state, suggesting that the Re(VII) uptake mechanism did not involve reduction of Re to a lower oxidation state, such as +4. The results of our studies using Re(VII) as an analogue for {sup 99}Tc(VII) suggest that {sup 99}Tc(VII) would also be sorbed with steel corrosion products and that the inventory of {sup 99}Tc(VII) released from breached waste packages would be lower than what is now conservatively estimated.

K.M. Krupka, C.F. Brown, H. Todd Schaef, S. M. Heald, M. M. Valenta, B. W. Arey

2006-04-30

380

Magnetic properties of maraging steel in relation to deformation and structural phase transformations  

SciTech Connect

Magnetic properties in annealed and cold rolled conditions have been investigated for maraging steel grade 18%Ni-2,400. The austenite content, coercive field, saturation magnetization and remanence were determined after aging for 1 h in the temperature range from 400 to 800 C. The results show that the degree of deformation imparted to martensite influences both the amount of reverted austenite and the magnetic properties obtained following aging. Transmission electron microscopy was carried out in order to investigate the structural changes taking place during reversion of austenite.

Ahmed, M.; Ali, A.; Hashmi, F.; Khan, A.Q. (Dr. A.Q. Khan, Research Labs., Rawalpindi (Pakistan)); Hasnain, S.K. (Quaid-e-Azam Univ., Islamabad (Pakistan). Dept. of Physics)

1994-03-01

381

Tensile properties of explosively formed 316L(N)-IG stainless steel with and without an electron beam weld  

NASA Astrophysics Data System (ADS)

The mechanical properties of two explosively formed saddle shaped 60 mm thick plates of 316L(N)-IG steel with and without an electron beam weld have been investigated. Two different conditions have been characterized: (1) Reference condition and (2) ITER relevant condition. The reference material exhibits consistent results for both plates, mechanical properties of reference material are similar to the properties previously observed for 316L(N)-IG steels. No significant difference in mechanical properties and microstructure between different positions in the 60 mm plate is observed. Tensile properties for ITER relevant materials are found to comply both with the RCC-MR code qualified data for 316L(N) steel used for the structural design and with ITER Materials Properties Handbook. As expected total elongation and uniform elongation for weld material are lower than the average curves obtained for the base material.

Hegeman, J. B. J.; Luzginova, N. V.; Jong, M.; Groeneveld, H. D.; Borsboom, A.; Stuivinga, M. E. C.; van der Laan, J. G.

2011-10-01

382

Effect of Cyclic Aging on Mechanical Properties and Microstructure of Maraging Steel 250  

NASA Astrophysics Data System (ADS)

The effects of thermal cyclic aging on mechanical properties and microstructure of maraging steel 250 were studied using hardness tester, tensile testing machine, impact tester, optical, scanning electron, and stereo microscopy. Samples were solution annealed at 1093 K for 1 h followed by air cooling to form bcc martensite. Cyclic aging treatments were carried out at 753 and 773 K for varying time periods. Increase in hardness and strength with corresponding decrease in ductility and impact strength was observed with increasing aging cycles. Reverted austenite was detected by x-ray diffraction technique formed as a result of cyclic aging. The presence of reverted ? was also confirmed by EDX-SEM analysis and attributed to the formation of Mo- and Ni-rich regions which transformed to ? on cooling. Heterogeneity in composition and amount of reverted ? was found to increase with increase in aging cycles and aging time. Fractography reveals the change in fracture mode from ductile dimple-like to brittle cleavage with increase in hardness and strength due to cyclic aging.

Tariq, Fawad; Naz, Nausheen; Baloch, Rasheed Ahmed

2010-10-01

383

Secondary recrystallization behavior and magnetic properties of grain oriented 2.2% Si-1.5% Mn steel  

NASA Astrophysics Data System (ADS)

The secondary recrystallization behavior and magnetic properties in ultralow carbon 2.2% Si-1.5% Mn steel containing 0.008% sol.Al was investigated. It was found that the atmosphere of final annealing plays an important role on the secondary recrystallization in this steel. In the case of annealing in N2 containing gas, good magnetic properties equivalent to those of conventional grain-oriented electrical steel were obtained. However, annealing in 100% H2 gas resulted in poor magnetic properties. Annealing in N2 containing gas can be considered as causing a sharp {110}<001? texture due to the strengthened inhibition resulting from an increase in fine nitrides. These results suggest the possibility of a new simple processing of grain-oriented electrical steel.

Yashiki, H.; Kaneko, T.

1993-05-01

384

Weld microstructure development and properties of precipitation-strengthened martensitic stainless steels  

SciTech Connect

Precipitation-strengthened martensitic stainless steels provide excellent strength (170--220 ksi Y.S.) with high corrosion resistance. However, upon aging, a large reduction in toughness may also occur. The gas tungsten arc (GTA) cold wire feed process was used to weld half inch thick plates of PH 13-8 Mo and Custom 450 from which both tensile and Charpy specimens were machined. A fundamental understanding of the details of weld microstructural evolution was developed by liquid tin quenching GTA welds in which the solidification behavior, primary phase of solidification, microsegregation, and solid-state transformations could be followed. For both alloys studied, the as-welded yield strengths were similar to those of the unaged base material, 130 ksi. Weld properties were very similar to those of the base materials for both alloy systems. Weld strength increases significantly upon aging and achieves a maximum at intermediate aging temperatures. The increase in strength is accompanied by a large decrease in Charpy impact energy; however, the minimum in toughness occurs at aging temperatures slightly less than those resulting in peak strengths. The evolution of the weld microstructure was found to support predictions of microstructural modeling. Although a high degree of alloying partitioning occurs during solidification, a large degree of homogenization occurs upon further solidification and cooling as a result of solid-state diffusion.

Brooks, J.

1994-12-31

385

Inactivation of murine norovirus by chemical biocides on stainless steel  

PubMed Central

Background Human norovirus (NoV) causes more than 80% of nonbacterial gastroenteritis in Europe and the United States. NoV transmission via contaminated surfaces may be significant for the spread of viruses. Therefore, measures for prevention and control, such as surface disinfection, are necessary to interrupt the dissemination of human NoV. Murine norovirus (MNV) as a surrogate for human NoV was used to study the efficacy of active ingredients of chemical disinfectants for virus inactivation on inanimate surfaces. Methods The inactivating properties of different chemical biocides were tested in a quantitative carrier test with stainless steel discs without mechanical action. Vacuum-dried MNV was exposed to different concentrations of alcohols, peracetic acid (PAA) or glutaraldehyde (GDA) for 5 minutes exposure time. Detection of residual virus was determined by endpoint-titration on RAW 264.7 cells. Results PAA [1000 ppm], GDA [2500 ppm], ethanol [50% (v/v)] and 1-propanol [30% (v/v)] were able to inactivate MNV under clean conditions (0.03% BSA) on the carriers by ? 4 log10 within 5 minutes exposure time, whereas 2-propanol showed a reduced effectiveness even at 60% (v/v). Furthermore, there were no significant differences in virus reduction whatever interfering substances were used. When testing with ethanol, 1- and 2-propanol, results under clean conditions were nearly the same as in the presence of dirty conditions (0.3% BSA plus 0.3% erythrocytes). Conclusion Products based upon PAA, GDA, ethanol and 1-propanol should be used for NoV inactivation on inanimate surfaces. Our data provide valuable information for the development of strategies to control NoV transmission via surfaces. PMID:19583832

2009-01-01

386

Electrochemical behaviour enhancement of stainless steels by a SiO 2 PACVD coating  

Microsoft Academic Search

Amorphous silica coatings have been deposited by plasma assisted chemical vapor deposition (PACVD) process on M2 steel and 304 stainless steel substrates. The chemical inertia of the coating has been established by resonant quartz crystal microbalance (RQCM), and no porosity has been observed at the AFM scale. The barrier effect has been evaluated on M2 steel by applying the concept

David Pech; Philippe Steyer; Jean-Pierre Millet

2008-01-01

387

Adsorption Removal of Phosphorus from Aqueous Solution by Steel Slag Columns  

Microsoft Academic Search

Removal of phosphorus from aqueous solution by steel slag column and the effects of the addition of boiler slag, furnace ash and quartz sand were investigated. After the adsorption treatment by the steel slag column, the residual phosphorus concentration was less than 0.5 mg\\/L. The adsorption performance of the steel slag column could be enhanced by the addition of quartz

Hua Zhang; Xuehong Zhang; Shaoyuan Bai; Yinian Zhu; Yuzhou Gong

2010-01-01

388

46 CFR 42.15-30 - Hatchways closed by weathertight covers of steel or other equivalent material fitted with gaskets...  

Code of Federal Regulations, 2012 CFR

...Hatchways closed by weathertight covers of steel or other equivalent material fitted with...Hatchways closed by weathertight covers of steel or other equivalent material fitted with...fitted with weathertight hatch covers of steel or other equivalent material...

2012-10-01

389

46 CFR 42.15-30 - Hatchways closed by weathertight covers of steel or other equivalent material fitted with gaskets...  

Code of Federal Regulations, 2010 CFR

...Hatchways closed by weathertight covers of steel or other equivalent material fitted with...Hatchways closed by weathertight covers of steel or other equivalent material fitted with...fitted with weathertight hatch covers of steel or other equivalent material...

2010-10-01

390

46 CFR 42.15-30 - Hatchways closed by weathertight covers of steel or other equivalent material fitted with gaskets...  

Code of Federal Regulations, 2014 CFR

...Hatchways closed by weathertight covers of steel or other equivalent material fitted with...Hatchways closed by weathertight covers of steel or other equivalent material fitted with...fitted with weathertight hatch covers of steel or other equivalent material...

2014-10-01

391

46 CFR 42.15-30 - Hatchways closed by weathertight covers of steel or other equivalent material fitted with gaskets...  

Code of Federal Regulations, 2013 CFR

...Hatchways closed by weathertight covers of steel or other equivalent material fitted with...Hatchways closed by weathertight covers of steel or other equivalent material fitted with...fitted with weathertight hatch covers of steel or other equivalent material...

2013-10-01

392

46 CFR 42.15-30 - Hatchways closed by weathertight covers of steel or other equivalent material fitted with gaskets...  

Code of Federal Regulations, 2011 CFR

...Hatchways closed by weathertight covers of steel or other equivalent material fitted with...Hatchways closed by weathertight covers of steel or other equivalent material fitted with...fitted with weathertight hatch covers of steel or other equivalent material...

2011-10-01

393

A New Approach to Argument by Analogy: Extrapolation and Chain Graphs Daniel Steel  

E-print Network

A New Approach to Argument by Analogy: Extrapolation and Chain Graphs Daniel Steel Department of Philosophy 503 S Kedzie Hall East Lansing, MI 48824-1032 steel@msu.edu #12;1. Introduction. In order to make

Steel, Daniel

394

Heat treatment for improvement in lower temperature mechanical properties of 0.40 pct C-Cr-Mo ultrahigh strength steel  

NASA Astrophysics Data System (ADS)

In the previous paper, it was reported that isothermal heat treatment of a commercial Japanese 0.40 pct C-Ni-Cr-Mo ultrahigh strength steel (AISI 4340 type) at 593 K for a short time followed by water quenching, in which a mixed structure of 25 vol pct lower bainite and 75 vol pct martensite is produced, results in the improvement of low temperature mechanical properties (287 to 123 K). The purpose of this paper is to study whether above new heat treatment will still be effective in commercial practice for improving low temperature mechanical properties of the ultrahigh strength steel when applied to a commercial Japanese 0.40 pct C-Cr-Mo ultrahigh strength steel which is economical because it lacks the expensive nickel component (AISI 4140 type). At and above 203 K this new heat treatment, as compared with the conventional 1133 K direct water quenching treatment, significantly improved the strength, tensile ductility, and notch toughness of the 0.40 pct C-Cr-Mo ultrahigh strength steel. At and above 203 K the new heat treatment also produced superior fracture ductility and notch toughness results at similar strength levels as compared to those obtained by using ? ?' repetitive heat treatment for the same steel. However, the new heat treatment remarkably decreased fracture ductility and notch toughness of the 0.40 pct C-Cr-Mo ultrahigh strength steel below 203 K, and thus no significant improvement in the mechanical properties was noticeable as compared with the properties produced by the conventional 1133 K direct water quenching treatment and the ? ?' repetitive heat treatment. This contrasts with the fact that the new heat treatment, as compared with the conventional 1133 K direct water quenching treatment and the ? ?' repetitive heat treatment, dramatically improved the notch toughness of the 0.40 pct C-Ni-Cr-Mo ultrahigh strength steel, providing a better combination of strength and ductility throughout the 287 to 123 K temperature range. The difference in the observed mechanical properties between the above two ultrahigh strength steels is discussed on the basis of the effect of nickel content, fracture profile, and so forth.

Tomita, Yoshiyuki; Okabayashi, Kunio

1983-11-01

395

Experimental Investigation of the Effect of Burnishing Force on Service Properties of AISI 1010 Steel Plates  

NASA Astrophysics Data System (ADS)

This paper presents the results obtained with a new ball burnishing tool developed for the mechanical treatment of large flat surfaces. Several parameters can affect the mechanical behavior and fatigue of workpiece. Our study focused on the effect of the burnishing force on the surface quality and on the service properties (mechanical behavior, fatigue) of AISI 1010 steel hot-rolled plates. Experimental results assert that burnishing force not exceeding 300 N causes an increase in the ductility. In addition, results indicated that the effect of the burnishing force on the residual surface stress was greater in the direction of advance than in the cross-feed direction. Furthermore, the flat burnishing surfaces did not improve the fatigue strength of AISI 1010 steel flat specimens.

Gharbi, F.; Sghaier, S.; Morel, F.; Benameur, T.

2015-02-01

396

Mechanical properties and oxidation and corrosion resistance of reduced-chromium 304 stainless steel alloys  

NASA Technical Reports Server (NTRS)

An experimental program was undertaken to identify effective substitutes for part of the Cr in 304 stainless steel as a method of conserving the strategic element Cr. Although special emphasis was placed on tensile properties, oxidation and corrosion resistance were also examined. Results indicate that over the temperature range of -196 C to 540 C the yield stress of experimental austenitic alloys with only 12 percent Cr compare favorably with the 18 percent Cr in 304 stainless steel. Oxidation resistance and in most cases corrosion resistance for the experimental alloys were comparable to the commercial alloy. Effective substitutes for Cr included Al, Mo, Si, Ti, and V, while Ni and Mn contents were increased to maintain an austenitic structure.

Stephens, J. R.; Barrett, C. A.; Gyorgak, C. A.

1979-01-01

397

Tensile Properties of Under-Matched Weld Joints for 950 MPa Steel.  

NASA Astrophysics Data System (ADS)

In welding of 950 MPa-class high tensile strength steel, preheating is crucial in order to avoid cold cracks, which, however, eventually increases welding deformations. One way to decrease welding deformations is lowering preheating temperature by using under-matched weld metal. Toyota and others clarify that although breaking elongation can decrease due to plastic constraint effect under certain conditions, static tensile of under-matched weld joints is comparable to that of base metal. However, there has still been no report about joint static tensile of under-matched weld joints applied to 950 MPa-class high tensile strength steel. In this study, we aim to research tensile strength and fatigue strength of under-matched weld joints applied to 950 MPa-class high tensile steel.

Yamamoto, Kouji; Arakawa, Toshiaki; Akazawa, Nobuki; Yamamoto, Kousei; Matsuo, Hiroki; Nakagara, Kiyoyuki; Suita, Yoshikazu

398

Shape control of alloy steel rolled by sendzimir mill  

Microsoft Academic Search

In order to improve quarter waves occurred in the wide and thin gauged alloy steel rolled by 20-high sendzimir mill, a computer\\u000a simulation based on the divided element method and an actual cold rolling experiment were carried out. Quarter waves were\\u000a simulated by elastic deformation analysis of rolls considering bending deformation of back up rolls and the effect of control

J. T. Kim; J. J. Yi; S. Y. Han

1996-01-01

399

Fatigue Properties of SUS304 Stainless Steel after Ultrasonic Nanocrystal Surface Modification (unsm)  

NASA Astrophysics Data System (ADS)

The changing of materials surface properties method always was taken into improving the fatigue strength. In this paper, an ultrasonic nanocrystal surface modification(UNSM) technique was used on the SUS 304 stainless steel to form a nanostructured surface layer with different static load(70N, 90N, 110N, 130N) and the vibration strike number was about 20,000times/mm2. The untreated and different condition specimens fatigue strength was all tested by a dual-spindle rotating bending fatigue test machine. SPring-8(a large synchrotron radiation facility) was used to test the surface nanocrystallization components. The X-ray diffraction (XRD), the scanning electron microscopy (SEM), optical microscope and a micro-Vickers hardness tester (MVK-E3, Akashi) were separately used to get the surface residual stresses, fracture surface after fatigue testing, metallographic structure and the microhardness of the nanostructured surface layer. The result showed that martensite transformation took place on the surface of specimens, the surface residual stresses had only a small increase and some cracks occurred between the martensite layer and the austenite layer, but the fatigue strength of 90N improved 81%.

Zhang, K. Y.; Pyoun, Y. S.; Cao, X. J.; Wu, B.; Murakami, R.

400

Microstructure and Properties of Cast B-Bearing High Speed Steel  

NASA Astrophysics Data System (ADS)

Microstructure, mechanical properties, and wear resistance of B-bearing high-speed steel (HSS) roll material containing 0.90-1.00% C, 1.3-1.5% B, 0.8-1.5% W, 0.8-1.5% Mo, 4.6-5.0% Cr, 1.0-1.2% V, and 0.15-0.20% Ti were studied by means of the optical microscopy (OM), the scanning electron microscopy (SEM), x-ray diffraction (XRD), hardness, impact toughness, and pin-on-disk abrasion tests. The results showed that as-cast structure of B-bearing HSS consisted of ?-Fe-, M23(B,C)6-, M3(B0.7C0.3)-, and M2(B,C)-type borocarbides, a small quantity of retained austenite, and a small amount of TiC. The hardness and impact toughness values of as-cast B-bearing HSS reached 65-67 HRC and 80-85 kJ/cm2, respectively. There were many M23(B,C)6-precipitated phases in the matrix after tempering, and then, with increasing temperature, the amount of precipitated phases increased considerably. Hardness of B-bearing HSS gradually decreased with the increasing tempering temperature, and the change of tempering temperature had no obvious effect on impact toughness. B-bearing HSS tempered at 500 C has excellent wear resistance, which can be attributed to the effect of boron.

Fu, Hanguang; Ma, Shengqiang; Hou, Jianqiang; Lei, Yongping; Xing, Jiandong

2013-04-01

401

The effects of novel surface treatments on the wear and fatigue properties of steel and chilled cast iron  

NASA Astrophysics Data System (ADS)

Contact fatigue driven wear is a principal design concern for gear and camshaft engineering of power systems. To better understand how to engineer contact fatigue resistant surfaces, the effects of electroless nickel and hydrogenated diamond-like-carbon (DLC) coatings on the fatigue life at 108 cycles of SAE 52100 steel were studied using ultrasonic fatigue methods. The addition of DLC and electroless nickel coatings to SAE 52100 bearing steel had no effect on the fatigue life. Different inclusion types were found to affect the stress intensity value beyond just the inclusion size, as theorized by Murakami. The difference in stress intensity values necessary to propagate a crack for Ti (C,N) and alumina inclusions was due to the higher driving force for crack extension at the Ti (C,N) inclusions and was attributed to differences in the shape of the inclusion: rhombohedral for the Ti (C,N) versus spherical for the oxides. A correction factor was added to the Murakami equation to account for inclusion type. The wear properties of DLC coated SAE 52100 and chilled cast iron were studied using pin-on-disk tribometry and very high cycle ultrasonic tribometry. A wear model that includes sliding thermal effects as well as thermodynamics consistent with the wear mechanism for DLCs was developed based on empirical results from ultrasonic wear testing to 108 cycles. The model fit both ultrasonic and classic tribometer data for wear of DLCs. Finally, the wear properties of laser hardened steels - SAE 8620, 4140, and 52100 - were studied at high contact pressures and low numbers of cycles. A design of experiments was conducted to understand how the laser processing parameters of power, speed, and beam size, as well as carbon content of the steel, affected surface hardness. A hardness maximum was found at approximately 0.7 wt% carbon most likely resulting from increased amounts of retained austenite. The ratcheting contact fatigue model of Kapoor was found to be useful in predicting the wear results. The empirical model of Clayton and Su and extended by Afferente and Ciavarella, also provided reasonable semi-quantitative contact fatigue life models for these steels.

Carroll, Jason William

402

Det&rmlrvatton af AuetenH vs. a-ferrlt Hi Steel by Neutron  

E-print Network

Det&rmlrvatton af AuetenH© vs. a-ferrlté Hi Steel by Neutron and X-ray Oif fraction Bltv Nitl-FERRITE IN STEEL BY NEUTRON AND X-RAY DIFFRACTION J. Als-Nielsen and K. Clausen Physics Department Abstract-ferrite) phases in steel samples are reported. In addition to determine the relative content of phases

403

Corrosion of stainless steels and carbon steel by molten mixtures of commercial nitrate salts  

Microsoft Academic Search

The isothermal corrosion behavior of two stainless steels and a carbon (C) steel in mixtures of NaNO3 and KNO3 was evaluated to determine if the impurities found in commodity grades of alkali nitrates aggravate corrosivity as applicable\\u000a to an advanced solar thermal energy system. Corrosion tests were conducted for approximately 7000 hours with Types 304 and\\u000a 316 stainless steels at

S. H. Goods; R. W. Bradshaw

2004-01-01

404

Tribological properties of novel imidazolium ionic liquids bearing benzotriazole group as the antiwear/anticorrosion additive in poly(ethylene glycol) and polyurea grease for steel/steel contacts.  

PubMed

The imidazolium ionic liquids (ILs) bearing benzotriazole group were synthesized and evaluated as antiwear (AW) and anticorrosion additive in poly(ethylene glycol) (PEG) and polyurea grease for steel/steel contacts at room temperature and 150 C. The physical properties of the synthetic ILs and PEG with the additive were measured. The anticorrosion property of the synthetic ILs was assessed via the accelerated corrosion test and copper strip corrosion test, which reveals the excellent anticorrosion properties in comparison with pure PEG and the selected conventional ILs having no benzotriazole group. Tribological results indicated that these ILs as the additives could effectively reduce friction and wear of sliding pairs in PEG and also in polyurea grease. The tribological properties were generally better than the normally used zincdialkyldithiophosphate-based additive package (T204) in polyurea grease. The wear mechanisms are tentatively discussed according to the morphology observation of worn surfaces of steel discs by scanning electron microscope (SEM) and the surface composition analysis by X-ray photoelectron spectroscopy (XPS). PMID:22026637

Cai, Meirong; Liang, Yongmin; Zhou, Feng; Liu, Weimin

2011-12-01

405

Microstructure and Mechanical Properties of Laser Clad and Post-cladding Tempered AISI H13 Tool Steel  

NASA Astrophysics Data System (ADS)

This study reports a detailed investigation of the microstructure and mechanical properties (wear resistance and tensile strength) of hardened and tempered AISI H13 tool steel substrate following laser cladding with AISI H13 tool steel powder in as-clad and after post-cladding conventional bulk isothermal tempering [at 823 K (550 C) for 2 hours] heat treatment. Laser cladding was carried out on AISI H13 tool steel substrate using a 6 kW continuous wave diode laser coupled with fiber delivering an energy density of 133 J/mm2 and equipped with a co-axial powder feeding nozzle capable of feeding powder at the rate of 13.3 10-3 g/mm2. Laser clad zone comprises martensite, retained austenite, and carbides, and measures an average hardness of 600 to 650 VHN. Subsequent isothermal tempering converted the microstructure into one with tempered martensite and uniform dispersion of carbides with a hardness of 550 to 650 VHN. Interestingly, laser cladding introduced residual compressive stress of 670 15 MPa, which reduces to 580 20 MPa following isothermal tempering. Micro-tensile testing with specimens machined from the clad zone across or transverse to cladding direction showed high strength but failure in brittle mode. On the other hand, similar testing with samples sectioned from the clad zone parallel or longitudinal to the direction of laser cladding prior to and after post-cladding tempering recorded lower strength but ductile failure with 4.7 and 8 pct elongation, respectively. Wear resistance of the laser surface clad and post-cladding tempered samples (evaluated by fretting wear testing) registered superior performance as compared to that of conventional hardened and tempered AISI H13 tool steel.

Telasang, Gururaj; Dutta Majumdar, Jyotsna; Wasekar, Nitin; Padmanabham, G.; Manna, Indranil

2015-02-01

406

Mechanical Properties of Steel Surfaces Coated with HfN/VN Superlattices  

NASA Astrophysics Data System (ADS)

Mechanical and tribological evolution on 4140 steel surfaces coated with hafnium nitride/vanadium nitride [HfN/VN] n multilayer systems deposited in various bilayer periods (?) via magnetron sputtering has been exhaustively studied in this work. The coatings were characterized in terms of structural, chemical, morphological, mechanical, and tribological properties by x-ray diffraction (XRD), x-ray photo electron spectroscopy (XPS), atomic force microscopy, scanning and transmission electron microscopy, nanoindentation, pin-on-disk, and scratch tests. Moreover, the failure mode mechanisms were observed via scanning electron microscopy. The XRD results showed preferential growth in the face-centered cubic (111) crystal structure for [HfN/VN] n multilayered coatings. The best enhancement of the mechanical behavior was obtained when the bilayer period (?) 15 nm (n = 80), yielding the highest hardness (37 GPa), and elastic modulus (351 GPa). The values for the hardness and elastic modulus were 1.48 and 1.32 times greater than the coating with n = 1, respectively, as well the lowest friction coefficient (~0.15) and the highest critical load (72 N). These results indicated significant enhancements in mechanical, tribological, and adhesion properties, compared to HfN/VN multilayered systems with bilayer period (?) of 1200 nm (n = 1). This hardness and toughness enhancement in the multilayered coatings could be attributed to the different mechanisms that produce the layer formation with nanometric thickness due to the number of interfaces acting as obstacles for crack deflection and dissipation of crack energy. Due to the emergent characteristics of the synthesized multilayered, the developed adaptive coating could be considered as higher ordered tool machining systems, capable of sustaining extreme operating conditions for industrial applications.

Escobar, C.; Villarreal, M.; Caicedo, J. C.; Aperador, W.; Prieto, P.

2014-09-01

407

Mechanical Properties of Steel Surfaces Coated with HfN/VN Superlattices  

NASA Astrophysics Data System (ADS)

Mechanical and tribological evolution on 4140 steel surfaces coated with hafnium nitride/vanadium nitride [HfN/VN] n multilayer systems deposited in various bilayer periods (?) via magnetron sputtering has been exhaustively studied in this work. The coatings were characterized in terms of structural, chemical, morphological, mechanical, and tribological properties by x-ray diffraction (XRD), x-ray photo electron spectroscopy (XPS), atomic force microscopy, scanning and transmission electron microscopy, nanoindentation, pin-on-disk, and scratch tests. Moreover, the failure mode mechanisms were observed via scanning electron microscopy. The XRD results showed preferential growth in the face-centered cubic (111) crystal structure for [HfN/VN] n multilayered coatings. The best enhancement of the mechanical behavior was obtained when the bilayer period (?) 15 nm ( n = 80), yielding the highest hardness (37 GPa), and elastic modulus (351 GPa). The values for the hardness and elastic modulus were 1.48 and 1.32 times greater than the coating with n = 1, respectively, as well the lowest friction coefficient (~0.15) and the highest critical load (72 N). These results indicated significant enhancements in mechanical, tribological, and adhesion properties, compared to HfN/VN multilayered systems with bilayer period (?) of 1200 nm ( n = 1). This hardness and toughness enhancement in the multilayered coatings could be attributed to the different mechanisms that produce the layer formation with nanometric thickness due to the number of interfaces acting as obstacles for crack deflection and dissipation of crack energy. Due to the emergent characteristics of the synthesized multilayered, the developed adaptive coating could be considered as higher ordered tool machining systems, capable of sustaining extreme operating conditions for industrial applications.

Escobar, C.; Villarreal, M.; Caicedo, J. C.; Aperador, W.; Prieto, P.

2014-11-01

408

Use of REM-Based Modifying Agents for Improving the Structure and Properties of Cast Tungsten-Molybdenum High-Speed Steels  

Microsoft Academic Search

Special features of the structure and properties of cast high-speed steels R6M5K5 and R6M5 modified by REM-based additives, i.e., ferrocerium in a design amount of 0.1, 0.3, 0.6, and 1.2% and silicomishmetal and alumoyttrium in a design amount of 0.1, 0.3, and 0.6% are studied. Results of metallographic, x-ray diffraction, fracture surface, and microscopic x-ray spectral analyses of the steels

A. S. Chaus

2004-01-01

409

Damping caused by microplasticity in porous 316L steels  

Microsoft Academic Search

Damping in porous structures is enhanced by localized stresses in comparison with corresponding dense materials. An analytical model for mechanical damping in porous materials is suggested for the microplastic range of deformation on the basis of the statistical mechanics of micro-heterogeneous materials. Two types of heterogeneity are considered: one-level porosity (directly sintered powder steels) and two-level porosity (larger pores in

I. K. Arhipov; I. S. Golovin; S. A. Golovin; H.-R. Sinning

2005-01-01

410

Optimization of chemical compositions in low-carbon Al-killed enamel steel produced by ultra-fast continuous annealing  

SciTech Connect

The influence of Mn,S and B contents on microstructural characteristics, mechanical properties and hydrogen trapping ability of low-carbon Al-killed enamel steel was investigated. The materials were produced and processed in a laboratory and the ultra-fast continuous annealing processing was performed using a continuous annealing simulator. It was found that increasing Mn,S contents in steel can improve its hydrogen trapping ability which is attributed by refined ferrite grains, more dispersed cementite and added MnS inclusions. Nevertheless, it deteriorates mechanical properties of steel sheet. Addition of trace boron results in both good mechanical properties and significantly improved hydrogen trapping ability. The boron combined with nitrogen segregating at grain boundaries, cementite and MnS inclusions, provides higher amount of attractive hydrogen trapping sites and raises the activation energy for hydrogen desorption from them. - Highlights: We study microstructures and properties in low-carbon Al-killed enamel steel. Hydrogen diffusion coefficients are measured to reflect fish-scale resistance. Manganese improves hydrogen trapping ability but decrease deep-drawing ability. Boron improves both hydrogen trapping ability and deep-drawing ability. Both excellent mechanical properties and fish-scale resistance can be matched.

Dong, Futao, E-mail: dongft@sina.com [The State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Du, Linxiu; Liu, Xianghua [The State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Xue, Fei [College of Electrical Engineering, Hebei United University, Tangshan 063000 (China)

2013-10-15

411

Effects of alloying elements on microstructure and fracture properties of cast high speed steel rolls  

Microsoft Academic Search

A study was made of the effects of alloying elements on microstructural factors of six high speed steel (HSS) rolls manufactured by centrifugal casting method. Particular emphasis was placed on the role of hard carbides located along solidification cell boundary and the type of the martensite matrix. Microstructural observation, X-ray diffraction analysis, and hardness measurement were conducted on the rolls

Keun Chul Hwang; Sunghak Lee; Hui Choon Lee

1998-01-01

412

Effect of contact conditions on embrittlement of T91 steel by leadbismuth  

Microsoft Academic Search

The T91 martensitic steel is a candidate structural material for the liquid leadbismuth eutectic (LBE) MEGAPIE spallation target. This paper first reviews some results on Liquid Metal Embrittlement (LME) of martensitic steels by liquid metals. It appears that LME of steels can occur provided a few criteria are fulfilled simultaneously. Intimate contact between liquid metal and solid metal is the

T. Auger; G. Lorang; S. Guerin; J.-L. Pastol; D. Gorse

2004-01-01

413

Microstructure and wear properties of Fe-VC-Cr{sub 7}C{sub 3} composite coating on surface of cast steel  

SciTech Connect

An Fe-VC-Cr{sub 7}C{sub 3} composite coating on the surface of cast steel was produced by a novel metal-coated casting technique. The microstructure and wear properties of the product were studied by means of X-ray diffraction, electron beam probe, scanning electron microscopy, and wear testing. The results show that the composite coating consisted of VC and Cr{sub 7}C{sub 3} as the reinforcing phases and {alpha}-Fe as the matrix. The composite coating was metallurgically bonded to the cast steel substrate. The quantity of VC and Cr{sub 7}C{sub 3} carbides decreased gradually from the top surface of the composite coating to the cast steel substrate. The Fe-VC-Cr{sub 7}C{sub 3} composite coating displayed excellent wear-resistance under dry sliding wear test conditions.

Cheng Fengjun [School of Manufacturing Science and Engineering, Sichuan University, Sichuan Chengdu 610065 (China)], E-mail: insephse@163.com; Wang Yisan; Yang Tinggui [School of Manufacturing Science and Engineering, Sichuan University, Sichuan Chengdu 610065 (China)

2008-04-15

414

Weld microstructure development and properties of precipitation-strengthened martensitic stainless steels  

SciTech Connect

The weld microstructural evolution, mechanical properties and solidification cracking susceptibility of three precipitation-strengthened martensitic stainless steels--PH 13-8 Mo, Custom 450 and 15-5 PH--were investigated. Liquid tin quenching of gas tungsten arc welds revealed that all three welds solidified as single-phase ferrite with a high degree of microsegregation. However, during further solidification and cooling almost complete homogenization occurred as a result of solid-state diffusion. The welds in all three alloys exhibited good resistance to solidification cracking and generally exhibited tensile and impact properties similar to those of the base metal. However, in almost all cases, the weld Charpy impact energies were somewhat less than those of the base metals. The cracking behavior and mechanical properties are discussed in terms of microstructural evolution.

Brooks, J.A. (Sandia National Labs., Livermore, CA (United States)); Garrison, W.R. Jr. (Carnegie-Mellon Univ., Pittsburgh, PA (United States))

1999-08-01

415

Quantitative nondestructive electronic and magnetic property assessment of heat treated grade p91 steel  

NASA Astrophysics Data System (ADS)

Structural steels experience aging from fatigue, creep and corrosion. Prolonged high temperature service accelerates creep and stress-corrosion cracking. Microstructural degradation of structural steels is a serious problem that limits the integrity of high-temperature parts in power plants. Some power plants that utilize fossil fuels have experienced lifecycle issues with heat-treated steel alloys that have experienced progressive damage over time. A nondestructive technique for the evaluation of the microstructure of key structural materials and the prediction of lifecycle has been the focus of extensive research for many years. Advanced nondestructive wave assessment techniques are being developed using electronic and magnetic perturbation analysis. These methods are applied to ferrous materials to determine whether a designed heat-treatment provides an acceptable microstructure offering specific set of required properties for the full service life of the component. The methods used in this research include impedance spectroscopy and hysteresis measurement as preliminary assessment methods and hysteresis frequency analysis and Barkhausen noise measurement as secondary assessment methods.

Meir, Shai Shmuel

416

Natural and synthetic rubber coatings for steel: Properties and compositions. (Latest citations from World Surface Coatings abstracts). Published Search  

SciTech Connect

The bibliography contains citations concerning the development and fabrication of natural and synthetic rubbers for use in coatings on steel. Coating materials include polyurethane elastomers, chlorinated rubber, and rubber-containing acrylic adhesives. References to bonding properties, mechanical strength, steel-wire reinforced rubbers, anticorrosion, and weather-resistance are covered. (Contains 50-250 citations and includes a subject term index and title list.)

NONE

1995-07-01

417

Evaluation of impact properties of weld joint of reactor pressure vessel steels with the use of miniaturized specimens  

Microsoft Academic Search

The effects of specimen size and location of V-notch on the Charpy impact properties were investigated with different sizes of specimens, standard, CVN-1\\/2, CVN-1\\/3, and CVN-1.5mm, for A533B steel, low Mn, high Cu, high phosphorus (P), and high Cu\\/P steel weld joint. A part of the specimens was irradiated with neutron at 563K up to 8נ10 n\\/cm. The heat affected

Byung Jun Kim; Hideaki Mitsui; Ryuta Kasada; Akihiko Kimura

2012-01-01

418

Experimental research on fatigue property of steel rubber vibration isolator for offshore jacket platform in cold environment  

Microsoft Academic Search

Jacket platform is the most widely used offshore platform. Steel rubber vibration isolator and damping isolation system are often used to reduce or isolate the ice-induced and seismic-induced vibrations. The previous experimental and theoretical studies concern mostly with dynamic properties, vibration isolation schemes and vibration-reduction effectiveness analysis. In this paper, the experiments on steel rubber vibration isolator were carried out

Yongjun Xu; Yubiao Liu; Changzhen Kan; Zhonghan Shen; Zhongmin Shi

2009-01-01

419

Corrosion resistance properties of glow-discharge nitrided AISI 316L austenitic stainless steel in NaCl solutions  

Microsoft Academic Search

Glow-discharge nitriding treatments can modify the hardness and the corrosion resistance properties of austenitic stainless steels. The modified layer characteristics mainly depend on the treatment temperature. In the present paper the results relative to glow-discharge nitriding treatments carried out on AISI 316L austenitic stainless steel samples at temperatures ranging from 673 to 773K are reported. Treated and untreated samples were

A. Fossati; F. Borgioli; E. Galvanetto; T. Bacci

2006-01-01

420

Microstructure and mechanical properties of laser welded dissimilar DP600\\/DP980 dual-phase steel joints  

Microsoft Academic Search

The use of dual phase (DP) steels in the automobile industry unavoidably involves welding and dynamic loading. The aim of this investigation was to evaluate the microstructural change and mechanical properties of laser welded dissimilar DP600\\/DP980 steel joints. The dissimilar joints showed a significant microstructural change from nearly full martensite in the fusion zone (FZ) to the unchanged ferritemartensite dual-phase

N. Farabi; D. L. Chen; Y. Zhou

2011-01-01

421

Microstructure and Mechanical Behavior of 17-4 Precipitation Hardenable Steel Processed by Selective Laser Melting  

NASA Astrophysics Data System (ADS)

The mechanical behavior and the microstructural evolution of 17-4 precipitation hardenable (PH) stainless steel processed using selective laser melting have been studied. Test coupons were produced from 17-4 PH stainless steel powder in argon and nitrogen atmospheres. Characterization studies were carried out using mechanical testing, optical microscopy, scanning electron microscopy, and x-ray diffraction. The results show that post-process heat treatment is required to obtain typically desired tensile properties. Columnar grains of smaller diameters (<2 m) emerged within the melt pool with a mixture of martensite and retained austenite phases. It was found that the phase content of the samples is greatly influenced by the powder chemistry, processing environment, and grain diameter.

Rafi, H. Khalid; Pal, Deepankar; Patil, Nachiket; Starr, Thomas L.; Stucker, Brent E.

2014-09-01

422

Microstructure and Mechanical Behavior of 17-4 Precipitation Hardenable Steel Processed by Selective Laser Melting  

NASA Astrophysics Data System (ADS)

The mechanical behavior and the microstructural evolution of 17-4 precipitation hardenable (PH) stainless steel processed using selective laser melting have been studied. Test coupons were produced from 17-4 PH stainless steel powder in argon and nitrogen atmospheres. Characterization studies were carried out using mechanical testing, optical microscopy, scanning electron microscopy, and x-ray diffraction. The results show that post-process heat treatment is required to obtain typically desired tensile properties. Columnar grains of smaller diameters (<2 m) emerged within the melt pool with a mixture of martensite and retained austenite phases. It was found that the phase content of the samples is greatly influenced by the powder chemistry, processing environment, and grain diameter.

Rafi, H. Khalid; Pal, Deepankar; Patil, Nachiket; Starr, Thomas L.; Stucker, Brent E.

2014-12-01

423

Microstructure, mechanical and fretting wear properties of TiC-stainless steel composites  

SciTech Connect

This study deals with the processing, microstructure, and wear behavior of TiC-reinforced stainless steel matrix composites, containing 50 to 70 wt.% TiC. Powder technology was used to successfully fabricate the composites. The microstructure of the composite was characterized by scanning electron microscopy. The microstructural study revealed that the TiC particles were distributed uniformly in the steel matrix phase. Interface debonding and microcracks were not observed in the composite. The composite hardness increased with TiC content. The fretting wear resistance of the composites was studied against high speed steel. The wear mechanisms are discussed by means of microscopical observations on the worn surfaces. The wear was severe at higher wear loads and lower TiC content. Microplowing of the stainless steel matrix was found to be the dominant wear mechanism. Heavy microplowing and rapid removal of material from the wear surface was observed at high wear load. The variation of wear loss with volume fraction and mean free path of the binder phase is also reported.

Akhtar, F. [Institute of Powder Metallurgy, School of Materials Science, University of Science and Technology Beijing, 30 Xue Yuan Road, 100083, Beijing (China); Department of Metallurgical and Materials Engineering, University of Engineering and Technology, Lahore (Pakistan)], E-mail: faridmet22@hotmail.com; Guo, S.J. [Institute of Powder Metallurgy, School of Materials Science, University of Science and Technology Beijing, 30 Xue Yuan Road, 100083, Beijing (China)

2008-01-15

424

Cyclic deformation property and microstructure study of HT-9 ferritic steel at elevated temperatures  

NASA Astrophysics Data System (ADS)

In this study, cyclic deformation tests were carried out on HT-9 steel at room temperature, 300, 400, 500 and 600C with a diametral strain range of 0.5%, 0.25% respectively. Transmission electron microscopy was presented to describe the micromechanisms of HT-9 steel under cyclic straining. The mechanical test results showed that cyclic softening behavior was observed at each testing temperature. The softening was attributed to the rearrangement of the high dislocation density structure into subgrain. In cyclically strained HT-9 specimens, carbides distributed along the subgrain boundaries. These carbides were considered to be the barriers against the subgrain to grow. The resistance of dislocation slip by carbides decreased to a less or extent at higher testing temperatures. The sharp subgrain boundaries observed in the specimens tested at higher temperatures showed a large decreasing rate in internal stress during cycling. HT-9 steel cyclically softened rapidly at testing temperatures higher than 500C. In the case of HT-9 steel cyclically deformed at lower strain range, cyclic plastic strain was essentially accommodated by the ferrite region and strain cycling did not have obvious effects on the substructure of lath martensite.

Han-Jou, Chang; Ji-Jung, Kai; Chuen-Horng, Tsai

1994-09-01

425

Structure and properties of a high-temperature austenitic steel at high temperatures  

NASA Astrophysics Data System (ADS)

The structure of a high-temperature austenitic 12Kh15N16M2TR steel, which is promising for manufacturing steam superheater tubes, is studied after long-term thermal holding under stress. The type, morphology, and matrix arrangement of excess-phase particles that form during thermal holding are found. The structure of the alloy correlates with its high-temperature strength, and the mechanical properties obtained during short-time tensile tests in the temperature range 20-730C are compared to the results of high-temperature strength tests.

Kostina, M. V.; Skorobogatykh, V. N.; Tykochinskaya, T. V.; Nakhabina, M. S.; Nemov, V. V.; Bannykh, I. O.; Korneev, A. E.

2010-11-01

426

Evolution of the structure and properties of silicon steels in the austenite-bainite phase transition  

NASA Astrophysics Data System (ADS)

The specific features of the structure of low-alloy silicon steels have been studied after the phase transition in the temperature range of the bainite transformation. It has been shown that the bainite transformation exhibits a pronounced two-stage character. At the first stage, the completely carbide-free bainite is formed, which contains up to 45% of residual austenite that is stable during deep cooling. The mechanical properties are studied as functions of the morphology and the carbon inhomogeneity of phases formed during the isothermal transformation in the bainite region.

Kaletin, A. Yu.; Kaletina, Yu. V.

2015-01-01

427

Magnetic properties of grain oriented electrical steel in model transformer under direct current-biased magnetization  

NASA Astrophysics Data System (ADS)

Iron losses and acoustic noises of the model transformer under DC-biased magnetization were empirically investigated. To clarify the influence of magnetic properties of transformer core materials, two types of grain oriented electrical steelshigh permeability grade (HGO) and conventional grade (CGO)were used as core materials. Iron losses increased with superimposing DC-bias magnetic field (HDC) in both materials, and the iron loss increment in HGO was larger than that in CGO. Acoustic noises increased with increasing HDC in both materials; however, noises emitted from the core of HGO were smaller than those of CGO.

Inoue, Hirotaka; Okabe, Seiji

2014-05-01

428

Interfacial debonding in steel beams strengthened by externally bonded CFRP  

NASA Astrophysics Data System (ADS)

The interfacial debonding at the plate ends is the most common failure mode in a carbon fibre reinforced polymer (CFRP) strengthened steel beam due to the high stress concentration there. This paper presents the results of a theoretical and experimental study on the interfacial debonding of the steel beams reinforced with CFRP plates. An analytical solution was developed to calculate the interfacial shear stress between the steel beam and the CFRP plate. The shear stress-slip relation of the bonding layer was simulated by a bilinear model. Three specimens were tested under threepoint bending. Two strain gauges were mounted at the ends of the plate bottom. If the effect of the spew fillet and the normal stress are ignored, the curves of strain recorded from the tests can be simplified to a bilinear model as well, which validates the theoretical results. When the strain is close to zero, the interfacial debonding initiated at the end of the plate. The agreement between the debonding loads obtained from the analytical solutions and the tests is good, which demonstrate that the presented analytical solution can predicate the debonding load correctly.

Deng, Jun; Lee, Marcus M. K.; Xie, Jian-he; Huang, Pei-yan

2008-11-01

429

Variation in Mechanical Properties and Heterogeneity in Microstructure of High-Strength Ferritic Steel During Mill Trial  

NASA Astrophysics Data System (ADS)

HS600 and HS800 are two new generation, high-strength advanced ferritic steels that find widespread application in automobiles. During commercial production of the same grades with different thicknesses, it has been found that mechanical properties like tensile strength and stretchability varied widely and became inconsistent. In the current endeavor, two different thicknesses have been chosen from a mill trial sample of HS600 and HS800. An in-depth structural characterization was carried out for all four alloys to explain the variation in their respective mechanical and shear punch properties. The carbon content was smaller and Ti + Mo quantity was higher in case of HS800 with respect to HS600. The microstructure of both steels consisted of the dispersion of (Ti,Mo)C in a ferrite matrix. The grain size of HS800 was little larger than HS600 due to an increased coiling temperature (CT) of the former in comparison to the latter. It was found that in case of same grade of steel with a different thickness, a variation in microstructure occurred due to change in strain, CT, and cooling rate. The strength and stretch formability of these two alloys were predominantly governed by a microalloyed carbide. In this respect, carbides with a size range above 5 nm were responsible for loosing coherency with ferrite matrix. In case of HS600, both ?5 and >5-nm size (Ti,Mo)C precipitates shared a nearly equal fraction of microalloyed precipitates. However, for HS800, >5-nm size (Ti,Mo)C carbide was substantially higher than ?5-nm size alloy carbides. The ultimate tensile strength and yield strength of HS800 was superior to that of HS600 owing to a higher quantity of microalloyed carbide with a decreased column width and interparticle distance. A higher degree of in-coherency of HS800 made the alloy prone to crack formation with low stretchability.

Ghosh, M.; Barat, K.; Das, S. K.; Ravi Kumar, B.; Pramanick, A. K.; Chakraborty, J.; Das, G.; Hadas, S.; Bharathy, S.; Ray, S. K.

2014-06-01

430

Elevated-temperature tensile and creep properties of several ferritic stainless steels  

NASA Technical Reports Server (NTRS)

The elevated-temperature mechanical properties of several ferritic stainless steels were determined. The alloys evaluated included Armco 18SR, GE 1541, and NASA-18T-A. Tensile and creep strength properties at 1073 and 1273 K and residual room temperature tensile properties after creep testing were measured. In addition, 1273 K tensile and creep tests and residual property testing were conducted with Armco 18SR and GE 1541 which were exposed for 200 hours to a severe oxidizing environment in automotive thermal reactors. Aside from the residual tensile properties for Armco 18SR, prior exposure did not affect the mechanical properties of either alloy. The 1273 K creep strength parallel to the sheet-rolling direction was similar for all three alloys. At 1073 K, NASA-18T-A had better creep strength than either Armco 18SR or GE 1541. NASA-18T-A possesses better residual properties after creep testing than either Armco 18SR or Ge 1541.

Whittenberger, J. D.

1977-01-01

431

Effect of deformation and annealing on the microstructure and magnetic properties of grain-oriented electrical steels  

NASA Astrophysics Data System (ADS)

The effect of plastic deformation and subsequent annealing on the magnetic properties and microstructure of a grain-oriented (GO) electrical steel has been studied. True strain (?) from 0.002 to 0.23 was applied by rolling in two directions, rolling (RD) and transverse (TD). The deterioration of power losses varies according to the direction of deformation. Annealing the strained materialat 800 C/2 hleads to a recrystallization and restored magnetic properties. The main components of annealed-textures are around 15-35 from those of deformed-textures for both RD and TD. Rolling along {1 1 0} <0 0 1> direction leads to the development of deformation twins.

Castro, Nicolau A.; de Campos, Marcos F.; Landgraf, Fernando J. G.

2006-09-01

432

Exploration of surface hydrophilic properties on AISI 304 stainless steel and silicon wafer against aging after atmospheric pressure plasma treatment  

NASA Astrophysics Data System (ADS)

The aim of this work is to seek the enhanced surface hydrophilic properties on AISI 304 stainless steel and silicon wafer after atmospheric pressure plasma treatment using a specifically designed atmospheric pressure plasma jet. The aging tendency of surface hydrophilic property under air is highlighted. It is concluded that both of the silicon wafer and stainless steel treated with plasma generated from supply gas of argon 15 slm mixed with oxygen 40 sccm shows a better tendency on remaining high water contact angle as compared to that with pure argon and nitrogen addition. Additional peaks of O I (777, 844 nm), O II (408 nm) are detected by optical emission spectroscope indicating the presence of the oxygen radicals and ionic species, which interact with surfaces and thus contribute to low water contact angle (WCA) surfaces. Moreover, the result acquired from X-ray photoelectron spectroscopy (XPS) indicates that the increase in the oxygen-related bonding exhibits a better contribution on remaining high surface energy over a period of time.

Chuang, Shang-I.; Duh, Jenq-Gong

2014-11-01

433

Effect of ultrasonic nanocrystal surface modification on surface and fatigue properties of quenching and tempering S45C steel  

NASA Astrophysics Data System (ADS)

Ultrasonic nanocrystal surface modification (USNM) utilizing ultrasonic vibration energy is a method which induces severe plastic deformation to a material's surface and an enhanced surface layer in order to produce a nano-structured surface. In this paper, USNM was performed to enhance the surface properties of quenched and tempered S45C steel by producing a nanostructured surface layer. Various processing parameters, such as static loading (50 N, 60 N and 70 N) and processing density (34,000 mm-2 and 68,000 mm-2), were applied in the surface treatment. The microstructure, hardness and residual stress of the material were analyzed. A rotating bending fatigue test was used to investigate the fatigue properties of the enhanced surface layer. A maximum static load of about 50 N was found for S45C steel process. As the strike number increased, a deeper refined grain layer and higher compressive residual stress was produced on the material's surface. The fatigue strength can be improved from 464 Mpa to about 550 Mpa through this process. Surface cracks, formed due to a heightened processing density of 68,000 mm-2, were found on the top surface layer of the material and large processing density was the reason of the formation of cracks.

Wu, Bo; Zhang, Jianxun; Zhang, Linjie; Pyoun, Young-Shik; Murakami, Ri-ichi

2014-12-01

434

Influence of repair welding of aged 18Ni 250 maraging steel weldments on tensile and fracture properties  

SciTech Connect

The effects of repair welding on tensile strength and fracture toughness of aged weldments of 18 Ni 250-grade maraging steel have been studied. It has been established that aged weldments in the steel can be repaired and approximately 95% of the tensile strength of the initial welds could be achieved by postrepair aging treatment. Also, the repairs had practically no effect on the fracture toughness (K[sub IC]) of the weldment. These results have been discussed in terms of microstructural conditions in the various affected and unaffected zones of the initial weld. One important inference that emerges from the mechanical properties-microstructural correlation in the study is that (K[sub IC]) of the weld is independent of the gross microstructural features of the dendritic size and shapes in the ranges observed in this study. It has, however, been cautioned that the above statement is not valid in cases in which heavy segregation occurs along the interdendritic boundaries resulting in heavily banded microstructure. This can result from faulty weld parameters such as excessive heat input. A second aging to recover the mechanical properties of the repaired zone has additional beneficial effects on tensile strengths and helps in maintaining fracture toughness to the original level of the initial weld.

Sinha, P.P.; Arumugham, S.; Nagarajan, K.V. (Vikram Sarabhai Space Center, Trivandrum (India). Materials and Metallurgy Group)

1993-08-01

435

Effect of Hydrogen on Mechanical Properties of 23Co14Ni12Cr3Mo Ultrahigh Strength Steel  

NASA Astrophysics Data System (ADS)

In order to evaluate the effect of hydrogen on mechanical properties of 23Co14Ni12Cr3Mo ultrahigh strength steel, the specimens were electrochemically hydrogen charged for different times. The tensile property, fatigue fracture behavior, fatigue crack growth (FCG) behavior, and threshold stress intensity (? K th) of the samples were studied. The fracture morphology was characterized by scanning electron microscopy. It was shown that tensile strength decreases from 2300 to 2000 MPa, critical fatigue stress from 577 to 482 MPa, and ? K th from 27.4 to 14.3 MPam0.5 with the increasing hydrogen contents from 0.0001 to 0.0008 wt.%. Hydrogen enhances the FCG rate from 2.4 10-3 to 3.6 10-3 mm/cycle at ? K = 80 MPam0.5 in the hydrogen-charging range. Microscopic observation showed that the tensile fracture is a combination of overload microvoids and some intergranular regions for 0 h, and isolated areas of transgranular (TG) fracture are observed with brittle cleavage for 24-72 h. The fatigue fracture is ductile for the uncharged specimens, while the hydrogen-charged specimens show mainly brittle TG fracture. These results suggest that hydrogen degrades the fracture behavior of 23Co14Ni12Cr3Mo ultrahigh strength steel.

Liu, Jianhua; Wen, Chen; Yu, Mei; Li, Songmei

2013-12-01

436

Effect of Nitrogen Content on Grain Refinement and Mechanical Properties of a Reversion-Treated Ni-Free 18Cr-12Mn Austenitic Stainless Steel  

NASA Astrophysics Data System (ADS)

Martensite reversion treatment was utilized to obtain ultrafine grain size in Fe-18Cr-12Mn-N stainless steels containing 0 to 0.44 wt pct N. This was achieved by cold rolling to 80 pct reduction followed by reversion annealing at temperatures between 973 K and 1173 K (700 C and 900 C) for 1 to 104 seconds. The microstructural evolution was characterized using both transmission and scanning electron microscopes, and mechanical properties were evaluated using hardness and tensile tests. The steel without nitrogen had a duplex ferritic-austenitic structure and the grain size refinement remained inefficient. The finest austenitic microstructure was achieved in the steels with 0.25 and 0.36 wt pct N following annealing at 1173 K (900 C) for 100 seconds, resulting in average grain sizes of about 0.240 0.117 and 0.217 0.73 m, respectively. Nano-size Cr2N precipitates observed in the microstructure were responsible for retarding the grain growth. The reversion mechanism was found to be diffusion controlled in the N-free steel and shear controlled in the N-containing steels. Due to a low fraction of strain-induced martensite in cold rolled condition, the 0.44 wt pct N steel displayed relatively non-uniform, micron-scale grain structure after the same reversion treatment, but it still exhibited superior mechanical properties with a yield strength of 1324 MPa, tensile strength of 1467 MPa, and total elongation of 17 pct. While the high yield strength can be attributed to strengthening by nitrogen alloying, dislocation hardening, and slight grain refinement, the moderate strain-induced martensitic transformation taking place during tensile straining was responsible for enhancement in tensile strength and elongation.

Behjati, P.; Kermanpur, A.; Najafizadeh, A.; Samaei Baghbadorani, H.; Karjalainen, L. P.; Jung, J.-G.; Lee, Y.-K.

2014-12-01

437

Improvement of Electrochemical Surface Properties in Steel Substrates Using a Nanostructured CrN/AlN Multilayer Coating  

NASA Astrophysics Data System (ADS)

Improvement of corrosion properties on AISI D3 steel surfaces coated with [CrN/AlN] n multilayered system deposited for various periods (?) via magnetron sputtering has been studied in this work exhaustively. For practical effects compared were the latter properties with CrN and AlN single layers deposited with the same conditions as the multilayered systems. The coatings were characterized in terms of crystal phase; chemical composition, micro-structural, and electrochemical properties by x-ray diffractometry, energy dispersive x-ray, Fourier transforming infrared spectroscopy, atomic force microscopy, scanning electron microscopy, Tafel polarization curves, and electrochemical impedance spectroscopy. Corrosion evolution was observed via optical microscopy. Results from x-ray diffractometry analysis revealed that the crystal structure of [CrN/AlN] n multilayered coatings has an NaCl-type lattice structure and hexagonal structure (wurtzite-type) for CrN and AlN, respectively, i.e., it was made non-isostructural multilayered. The best behavior was obtained by the multilayered period: ? = 60 nm (50 bilayers), showing the maximum corrosion resistance (polarization resistance of 1.18 K?, and corrosion rate of 1.02 mpy). Those results indicated an improvement of anticorrosive properties, compared to the CrN/AlN multilayer system with 1 bilayer at 98 and 80%, respectively. Furthermore, the corrosion resistance of steel AISI D3 is improved beyond 90%. These improvement effects in multilayered coatings could be attributed to the number of interfaces that act as obstacles for the inward and outward diffusions of ion species, generating an increment in the energy or potential required for translating the corrosive ions across the coating/substrate interface. Moreover, the interface systems affect the means free path on the ions toward the metallic substrate, due to the decreasing of the defects presented in the multilayered coatings.

Cabrera, G.; Torres, F.; Caicedo, J. C.; Aperador, W.; Amaya, C.; Prieto, P.

2012-01-01

438

Influence of surface roughness on the semiconducting properties of oxide films formed on 304 stainless steel  

Microsoft Academic Search

Oxide films were formed at 350C in borate buffer solution on AISI 304 stainless steel priory abraded with wet SiC paper\\u000a of different grit size. The films were characterised by Atomic Force Microscopy (AFM) and studied by capacitance, impedance,\\u000a and photocurrent measurements. The images obtained by AFM microscopy show the evolution of the surface roughness of the films\\u000a with increasing

N. E. Hakiki

2008-01-01

439

Basic properties of sintering dust from iron and steel plant and potassium recovery.  

PubMed

With the production of crude steel, China produces several million tons of sintering dusts which contain a great deal of valuable metals such as, K, Na,