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1

INVESTIGATION TOWARD OBTAINING SIGNIFICANTLY HIGHER MECHANICAL PROPERTIES OF AS-WELDED JOINTS IN HIGH-STRENGTH, HEAT TREATABLE ALUMINUM ALLOYS  

Microsoft Academic Search

Welding techniques, filler metal-parent metal selection, and moderate ; temperature post-weld thermal treatments are described which were employed to ; achieve tensile strengths up to 72,000 pounds per square inch (psi) in welded ; heat treatable aluminum alloy sheet. The aluminum-zinc-magnesium-copper (Al - ; Zn - Mg -Cu) alloys 7075 and 7178 welded Al-Mg or Al-Mg-Zn filler metals gave ;

1961-01-01

2

Microstructure and Properties Analysis of Laser Welding and Laser Weld Bonding Mg to Al Joints  

NASA Astrophysics Data System (ADS)

Laser welding and laser weld bonding (LWB) Mg to Al joints were obtained in different welding parameters. The penetrations and microstructures of these kinds of joints changed with the increasing of pulse laser power density. Both laser welding and LWB Mg to Al joints with the best properties were obtained in conductive welding mode. In laser welding Mg to Al joint, several intermetallics formed at the bottom of the fusion zone, where some cracks were generated. In laser weld bonding Mg to Al joint, the decomposition of the adhesive caused a baffle effect on the diffusion between the Mg and the Al. The intermetallics formed in the middle of the fusion zone, and the thickness of Mg17Al12 layer was approximately 10 to 20 ?m and the Mg2Al3 layer was less than 5 ?m, which influenced the property of the joint less.

Liu, Liming; Wang, Hongyang

2011-04-01

3

Obtaining weld pool vision information during aluminium alloy TIG welding  

Microsoft Academic Search

An image sensing system for the TIG (tungsten inert-gas arc) welding process of aluminium alloy was established. The relationships between the image sensing system and the characteristic of welding current were discussed in detail. Front and back images of the weld pool were obtained with different welding parameters. In order to process the image, the characteristics of an aluminium alloy

J. J. Wang; T. Lin; S. B. Chen

2005-01-01

4

DYNAMIC FRACTURE OF WELDED JOINTS  

Microsoft Academic Search

This paper presents an experimental and analytical investigation of dynamic fracture of T-shaped welded joints (stiffener on a plate) in a high strength steel. A fracture test was designed in which strain rates of several thousand per second can be reached in the weldment region by loading the specimen with tamped explosive. Test conditions can be reliably controlled by adjusting

J. H. GIOVANOLA; R. W. KLOPP; S. W. KIRKPATRICK; W. W. McDONALD

1991-01-01

5

Joint tracking and adaptive robotic welding using vision sensing of the weld joint geometry  

SciTech Connect

An approach to the vision-guidance of welding robots and the in-process adjustment of welding conditions is presented. The implementation of a complete vision-guided adaptive robotic welding system is described. The vision-guided adaptive welding system described here has been used to track and weld a wide variety of test and production parts ranging in size from 1.6-mm (1/16-in.) sheet steel to 19.1-mm (3/4-in.) steel plate. Both conventional joint types, including square butt, lap, and V-groove, and special types, such as a multipass square butt submerged arc weld with pre-welded root passes or the axle joints were welded. Various welding procedures, such as GMA welding with a variety of shielding gases and submerged arc welding, have also been used.

Agapakis, J.E.; Katz, J.M.; Koifman, M.; Epstein, G.N.; Friedman, J.M.; Eyring, D.O.; Rutishauser, H.J.

1986-11-01

6

Hydrogen damage in friction welded copper joints  

Microsoft Academic Search

The occurrence of hydrogen attack in electrolytic copper and in copper deoxidized with phosphorous, during model heating in oil and in friction welded specimens was investigated. Dissimilar-metal joints, i.e. copper\\/TZM (titanium–zirconium–molybdenum based alloy) joints and copper\\/austenitic steel joints, were subjected to microstructural examinations and tensile strength tests.Microcracks near the weld surface, caused by hydrogen attack, were found to occur in

Andrzej Ambroziak

2010-01-01

7

Comparative studies on stresses in weld-bonded, spot-welded and adhesive-bonded joints  

Microsoft Academic Search

A numerical analysis on the distribution of stresses in weld-bonded joints is carried out using a three-dimensional elastoplastic finite-element method. A comparison is made of the stresses distribution in weld-bonded joints, spot-welded joints and adhesive-bonded joints. The results show that the stresses in the lap zone of weld-bonded joints are distributed uniformly, no high-stress zone being found in weld-bonded joints.

Baohua Chang; Yaowu Shi; Shijie Dong

1999-01-01

8

Improving fatigue strength of welded joints  

NASA Astrophysics Data System (ADS)

One series of fatigue tests was carried out on coverplated bridge girders with small fatigue cracks that had been treated in 1976. The treatment and preconditions were reported in NCHRP Report 206. The Category E' coverplated. beams that were removed from the Yellow Mill Pond Bridge in 1997 had been retrofitted in 1976 by either air hammer peening or GTA remelting the weld toe. Most of the details had small fatigue cracks at the time the retrofit was carried out. No detectable fatigue cracking was observed at the treated coverplate ends after 20 years of service on I-95 and an estimated 56 million truck passages. All beams were tested at a stress range of 69 MPa (10 ksi). Cracks eventually developed from the root of the transverse end welds and propagated through the weld throat and from there into the beam flange via the longitudinal welds. The fatigue resistance of the treated weld toe details was improved to Category C. The one GTA remelted detail that recracked at the weld toe exceeded Category D. The second series of tests was carried out on large scale HPS-485W steel plate girders with as-welded and ultrasonic impact treated (UIT) details. The UIT treatment was applied to the weld toe of transverse stiffeners welded to the web and flanges (Category C details) and to coverplated ends (Category E' details). The as-welded details cracked as expected at their corresponding fatigue resistance. All UIT treated details were improved. The treated transverse stiffeners achieved Category B fatigue resistance. The treated coverplated details achieved Category C. The third series of tests was conducted on large scale HPS-485W steel plate girders with undermatched groove welded details at flange transition. The objectives of using undermatched weld materials compared to the base material is to reduce the potentiality of hydrogen cracking at flange groove welds and to improve the fatigue strength of the welded joints. Fatigue strength of undermatched welded joints was approximately the same as that resulted from conventionally welded joints. The undermatched groove welded joints achieved Category B fatigue resistance.

Takamori, Hiroyuki

9

Effects of friction welding conditions on the mechanical properties of friction welded joints in 7075 aluminium alloy  

Microsoft Academic Search

Friction welding was carried out under various welding conditions using high strength 7075 aluminium alloy; an investigation into the structure and the mechanical properties of joints thus obtained leads to the following conclusions: The fibrous structure at the heat affected zone changed to align in the direction of flash expulsion and the fibrous structure at the weld zone disappeared and

H. Fuwana; K. Katoh; H. Tokisue

1997-01-01

10

Toughness evaluation of a shielded metal arc carbon-manganese steel welded joint subjected to multiple post weld heat treatment  

Microsoft Academic Search

This study was part of a program to investigate the influence of multiple post weld heat treatment (PWHT) on the fracture\\u000a toughness and defect tolerance of a welded joint. The present work reports base metal data obtained for a quenched and tempered\\u000a BS7191 Grade 450EM steel (0.10wt%C–1.08wt%Mn), weld metal data for a ferritic multipass weld obtained by shielded metal arc

I. de S. Bott; J. C. G. Teixeira

1999-01-01

11

Fatigue Strength Assessment of the Fillet Welded Cruciform Joints  

Microsoft Academic Search

In this study, fatigue tests to obtain S-N curves and FE analyses to obtain structural stress concentration factors were conducted for two types of fillet welded cruciform joints, that is, load-carrying and non load-carrying types. The obtained S-N curve of the load-carrying joint was changed to that based on hot-spot stress. As a result, the S-N curve of the load-carrying

Dae-Jin Kim; Chang-Sung Seok; Jae-Mean Koo

2006-01-01

12

Diagnostic test systems canister weld joint analysis  

Microsoft Academic Search

The Test Systems Section of the Nuclear Test Engineering Division has been developing standard components for its family of canisters. One area of concern in the design has been the weld joints between the main canister channels and the canister endplates. The Solid Mechanics Group of Engineering Mechanics performed numerical calculations on this joint with the SAP4 finite element code

1981-01-01

13

Fatigue Strength Assessment of the Fillet Welded Cruciform Joints  

NASA Astrophysics Data System (ADS)

In this study, fatigue tests to obtain S-N curves and FE analyses to obtain structural stress concentration factors were conducted for two types of fillet welded cruciform joints, that is, load-carrying and non load-carrying types. The obtained S-N curve of the load-carrying joint was changed to that based on hot-spot stress. As a result, the S-N curve of the load-carrying joint based on hot-spot stress almost coincided with that of the non load-carrying joint based on nominal stress. The fatigue strength of a welded joint which has a different geometry from that of the non load-carrying cruciform joint but the same bead profile as that of the non load-carrying cruciform joint could be estimated by using both the structural stress concentration factor at the weld toe position obtained from FEM and the nominal S-N curve of the non load-carrying cruciform joint from experiment.

Kim, Dae-Jin; Seok, Chang-Sung; Koo, Jae-Mean

14

Stress corrosion cracking susceptibility of dissimilar stainless steels welded joints  

Microsoft Academic Search

Purpose: The aim of the current study is to reveal the influence of welding conditions on structure and stress corrosion cracking resistance of dissimilar stainless steels butt welded joints. Design\\/methodology\\/approach: Butt joints between duplex 2205 and austenitic 316L steels were performed with the use of submerged arc welding (SAW) method. The plates 15 mm in thickness were welded with heat

J. ?abanowski

15

Extending ITER materials design to welded joints  

NASA Astrophysics Data System (ADS)

This paper extends the ITER materials properties documentation to weld metals and incorporates the needs of Test Blanket Modules for higher temperature materials properties. Since the main structural material selected for ITER is type 316L(N)-IG, the paper is focused on weld metals and joining techniques for this steel. Materials properties data are analysed according to the French design and construction rules for nuclear components (RCC-MR) and design allowables are equally derived using the same rules. Particular attention is paid to the type of weld metal, to the type and position of welding and their influence on the materials properties data and design allowables. The primary goal of this work, starting with 19-12-2 weld metal, is to produce comprehensive materials properties documentations that when combined with codification and inspection documents would satisfy ITER licensing needs. As a result, structural stability and capability of welded joints during manufacturing of ITER components and their subsequent service, including the effects of irradiation and eventual incidental or accidental situations, are also covered.

Tavassoli, A.-A. F.

2007-08-01

16

The effect of controlled shot peening on fusion welded joints  

Microsoft Academic Search

This work examines the effect of controlled shot peening (CSP) treatment on the fatigue strength of an ASTM A516 grade 70 carbon steel welded joint. Metallurgical modifications, hardness, elemental compositions, and internal discontinuities, such as porosity, inclusions, lack of penetration, and undercut found in treated and untreated fusion welded joints, were characterized. The fatigue results of as-welded and peened skimmed

Nur Azida Che Lah; Aidy Ali; Napsiah Ismail; Lim Poon Chai; Abdul Aziz Mohamed

2010-01-01

17

An analysis of fatigue cracks in fillet welded joints  

Microsoft Academic Search

In most of the lower fatigue strength welded joints failure occurs by the propagation of a semi-elliptical surface crack which initiates at the weld toe. In order to analyse the progress of these cracks using fracture mechanics techniques, the solution for the stress intensity factor, K, is required. Fatigue cracks in most welded joints adopt shapes which give low a\\/2c

S. J. Maddox

1975-01-01

18

Effect of welding speed on butt joint quality of Ti–6Al–4V alloy welded using a high-power Nd:YAG laser  

Microsoft Academic Search

Annealed Ti–6Al–4V alloy sheets with 1 and 2mm thickness are welded using a 4kW Nd:YAG laser system. The effects of welding speed on surface morphology and shape, welding defects, microstructure, hardness and tensile properties are investigated. Weld joints without or with minor cracks, porosity and shape defects were obtained indicating that high-power Nd:YAG laser welding is a suitable method for

X. Cao; M. Jahazi

2009-01-01

19

Effect of welding parameters on mechanical and microstructural properties of AA6056 joints produced by Friction Stir Welding  

Microsoft Academic Search

The effect of processing parameters on mechanical and microstructural properties of AA6056 joints produced by Friction Stir Welding was analysed in the present study. Different samples obtained by employing rotating speeds of 500, 800 and 1000rpm and welding speeds of 40, 56 and 80mm\\/min were produced. The mechanical properties of the joints were evaluated by means of microhardness (HV) and

P. Cavaliere; G. Campanile; F. Panella; A. Squillace

2006-01-01

20

Effect of weld geometry on the fatigue life of non-load-carrying fillet welded cruciform joints  

Microsoft Academic Search

In the present study, the effect of weld geometry on the fatigue life of non-load-carrying fillet welded cruciform joints was experimentally investigated. The weld geometry of the cruciform specimens was intentionally varied, and fatigue tests were carried out on various weld geometry configurations. The configurations included weld flank angle, weld toe radius and weld throat thickness. Constant amplitude fatigue tests

Chin-Hyung Lee; Kyong-Ho Chang; Gab-Chul Jang; Chan-Young Lee

2009-01-01

21

Adaptive tracking of weld joints using active contour model in arc-welding processes  

NASA Astrophysics Data System (ADS)

12 This paper presents a vision processing scheme to automatic weld joint tracking in robotic arc welding process. Particular attention is concentrated on its robustness against various optical disturbances, such as arc glares and weld spatters radiating from the melted weld pool. Underlying the developed vision processing is a kind of model-based pattern searching, which is necessarily accompanied by two separate stages of modeling and tracking. In the modeling stage, a syntactic approach is adopted to identify unknown weld joint structure. The joint profile identified in the modeling stage is used as a starting point for successive tracking of variations in the geometry of weld joint during welding, which is automatically achieved by an active contour model technology following feature- based template matching. The performance of the developed scheme is investigated through a series of practical welding experiments.

Kim, Jaeseon; Koh, Kyoungchul; Cho, Hyung S.

2001-02-01

22

ADAPTIVE HEALTH MONITORING CONCEPTS FOR SPOT-WELDED AND WELD-BONDED STRUCTURAL JOINTS  

Microsoft Academic Search

The health monitoring of structural joints is a major concern of the engineering community and needs to be addressed with the proper consideration. Among joining techniques, the spot welding and weld-bonding (spot weld + adhesive bonding) methods are of great interest in a number of industries. Spot welding is the traditional assembly method for steel-based automotive structures, while weld-bonding is

Victor Giurgiutiu; Craig A. Rogers; Yuh Jin Chao; Michael A. Sutton; Xiaomin Deng

1997-01-01

23

Virtual Welded - Joint Design Integrating Advanced Materials and Processing Technology  

SciTech Connect

Virtual Welede-Joint Design, a systematic modeling approach, has been developed in this project to predict the relationship of welding process, microstructure, properties, residual stress, and the ultimate weld fatique strength. This systematic modeling approach was applied in the welding of high strength steel. A special welding wire was developed in this project to introduce compressive residual stress at weld toe. The results from both modeling and experiments demonstrated that more than 10x fatique life improvement can be acheived in high strength steel welds by the combination of compressive residual stress from the special welding wire and the desired weld bead shape from a unique welding process. The results indicate a technology breakthrough in the design of lightweight and high fatique performance welded structures using high strength steels.

Yang, Zhishang; Ludewig, Howard W.; Babu, S. Suresh

2005-06-30

24

Seam-Tracking for Friction Stir Welded Lap Joints  

NASA Astrophysics Data System (ADS)

This article presents a method for automatic seam-tracking in friction stir welding (FSW) of lap joints. In this method, tracking is accomplished by weaving the FSW tool back-and-forth perpendicular to the direction of travel during welding and monitoring force and torque signals. Research demonstrates the ability of this method to automatically track weld seam positions. Additionally, tensile and S-bend test result comparisons demonstrate that weaving most likely does not reduce weld quality. Finally, benefits of this weave-based method to FSW of lap joints are discussed and methods for incorporating it into existing friction stir welding control algorithms (such as axial load control) are examined.

Fleming, Paul A.; Hendricks, Christopher E.; Cook, George E.; Wilkes, D. M.; Strauss, Alvin M.; Lammlein, David H.

2010-11-01

25

Effect of Friction Welding Condition on Joining Phenomena and Tensile Strength of Friction Welded joint between Pure Copper and Low Carbon Steel  

NASA Astrophysics Data System (ADS)

This paper describes the effect of the friction welding condition on the joining phenomena and tensile strength of friction welded joint between pure copper (OFC) and low carbon steel (LCS). When the joint was made at friction pressure of 30 MPa with friction speed of 27.5 s-1, OFC transferred to the half radius region of the weld interface on the LCS side, and then transferred toward the entire weld interface. The temperatures at the centerline, half radius and periphery portions on the weld interface of the LCS side were almost the same after the initial peak. When the joint was made at a friction time of 2.4 s, i.e. the friction torque was close to the initial peak, that had obtained approximately 40% joint efficiency and fractured from the weld interface with a little OFC adhering to the weld interface on the LCS side. The joint efficiency increased with increasing forge pressure, and it reached approximately 80% at a forge pressure of 180 MPa. This joint fractured at the softened OFC region adjacent to the weld interface. On the other hand, OFC transferred to the peripheral region of the weld interface on the LCS side when the joint was made at friction pressure of 90 MPa with friction speed of 27.5 s-1. However, OFC transfer was not obtained at the central region because the temperature at the periphery portion was higher than that of the other portions. The joint efficiency increased with increasing friction time, and it obtained approximately 74% at a friction time of 1.2 s. Moreover, all joints fractured between the OFC side and the weld interface, although the joints were made with higher forge pressure. To obtain higher joint efficiency and fracture in the OFC side, the joint should be made with low friction pressure and high forge pressure, and with the friction time at which the friction torque reaches the initial peak.

Kimura, Masaaki; Kusaka, Masahiro; Kaizu, Koichi; Fuji, Akiyoshi

26

Low cycle fatigue strength assessment of cruciform welded joints  

Microsoft Academic Search

This paper presents the results of an experimental study on the low cycle fatigue strength of cruciform welded joints. Tests were performed on 22 specimens of three different categories, namely full-penetration, partial-penetration and fillet welded cruciform joints. These tests consisted basically of imposing on each specimen a constant amplitude cyclic displacement history in the plastic range of the material behaviour.

João Ferreira; Carlo A Castiglioni; Luis Calado; M Rosaria Agatino

1998-01-01

27

Comparison of Post Weld Treatment of High Strength Steel Welded Joints in Medium Cycle Fatigue  

Microsoft Academic Search

This paper presents a comparison of three post weld treatments for fatigue life improvement of welded joints. The objective is to determine the most suitable post weld treatment for implementation in mass production of certain crane components manufactured from very high strength steel. The processes investigated are; burr grinding, TIG dressing and ultrasonic impact treatment. The focus of this investigation

M. M. Pedersen; O. Ø. Mouritsen; M. R. Hansen; J. G. Andersen; J. Wenderby

28

Improving Fatigue Life for Aluminum Cruciform Joints by Weld Toe Grinding  

Microsoft Academic Search

Fatigue improvement by weld toe grinding for aluminum welded joints has been investigated in this paper. Fatigue tests were performed for a number of as- welded and toe-ground non-load carrying cruciform joints. Finite element analyses were carried out to further study the influence of the variation of the main weld parameters such as the weld toe angle, weld toe radius

Naiquan Ye; Torgeir Moan

29

Fatigue and Damage Tolerance of Friction Stir Welded Joints for Aerospace Applications  

Microsoft Academic Search

Friction stir welding is a young welding process with high potential to replace riveted joints in aerospace structures like the fuselage. Friction stir welding is a robust process and capable of welding high strength aluminum alloys. Therefore it can lead to both costs and weight savings. To substitute riveted joints by friction stir welded joints, it must be shown that

H. J. K. Lemmen

2010-01-01

30

Residual stress relief in MAG welded joints of dissimilar steels  

Microsoft Academic Search

This paper addresses the relief of residual stress in welded joints between austenitic and non-alloyed ferritic–pearlitic steels. A series of similar and dissimilar steel joints based on the 18G2A (ferritic–pearlitic) and 1H18N10T (austenitic) steels were produced, some of which were stress relieved by annealing and some by mechanical prestressing. For the as-welded and stress relieved test joints the residual stresses

P Sedek; J. Brózda; L. Wang; P. J. Withers

2003-01-01

31

Tensile and Impact Toughness Properties of Gas Tungsten Arc Welded and Friction Stir Welded Interstitial Free Steel Joints  

NASA Astrophysics Data System (ADS)

Welded regions of interstitial free (IF) steel grades in the vicinity of weld center exhibits larger grains because of the prevailing thermal conditions during weld metal solidification. This often causes inferior weld mechanical properties. In the present study, tensile properties, charpy impact toughness, microhardness, microstructure, lowest hardness distribution profile, and fracture surface morphology of the gas tungsten arc welded (GTAW) and friction stir welded joints were evaluated, and the results are compared. From this investigation, it is found that friction stir welded joint of IF steel showed superior tensile and impact properties compared with GTAW joint, and this is mainly due to the formation of very fine, equiaxed microstructure in the weld zone.

Lakshminarayanan, A. K.; Balasubramanian, V.

2011-02-01

32

Stress concentration factor analysis for notched welded tubular T-joints  

Microsoft Academic Search

In this study, the finite element method (FEM) is applied on a welded tubular T-joint, in order to analyse stress distribution in the vicinity of the weld fillet. The weld has been modelled all around the joint. A notch is to be simulated in the weld element, all around the joint as well. Using symmetry, the tubular T-joint is submitted

A. N’Diaye; S. Hariri; G. Pluvinage; Z. Azari

2007-01-01

33

Numerical and Experimental Determination of Strain (Stress) Concentration Factors of Welded Joints between Square Hollow Sections  

Microsoft Academic Search

This article presents methods of approach for finite element modelling of joints made of rectangular hollow steel sections where the brace members are welded to the face of the chord, to obtain strain (stress) concentration factors, SNCF (SCF). X, T and K type joints are considered. Simple modelling methods are applied for practical reasons, so that straight-forward use in large

R. S. Puthli; J. Wardenier; C. H. M. De Koning; A. M. Van Wingerde; F. J. Van Dooren

1988-01-01

34

Resistance welding of thermoplastic composites skin\\/stringer joints  

Microsoft Academic Search

An experimental investigation of resistance welding of APC-2\\/AS4 PEEK\\/carbon fibre composite using a stainless steel mesh heating element is presented. A special specimen geometry, the skin\\/stringer configuration, was used to represent a typical reinforced aerospace structural joint. The specimens consisted of a flange, representing a stringer or frame, welded onto a skin laminate. The effects of the welding parameters such

M. Dubé; P. Hubert; A. Yousefpour; J. Denault

2007-01-01

35

An inelastic analysis of a welded aluminum joint  

SciTech Connect

Butt weld joints are most commonly designed into pressure vessels by using weld material properties that are determined from a tensile test. These properties are provided to the stress analyst in the form of a stress vs strain diagram. Variations in properties through the thickness of the weld and along the width of the weld have been suspect but not explored because of inaccessibility and cost. The purpose of this study is to investigate analytical and computational methods used for analysis of multiple pass aluminum 2219-T87 butt welds. The weld specimens are analyzed using classical plasticity theory to provide a basis for modeling the inelastic properties in a finite element solution. The results of the analysis are compared to experimental data to determine the weld behavior and the accuracy of currently available numerical prediction methods.

Vaughan, R.E. [Marshall Space Flight Center, Huntsville, AL (United States). Structures and Dynamics Lab.; Schonberg, W.P. [Univ. of Alabama, Huntsville, AL (United States). Civil and Environmental Engineering Dept.

1995-12-01

36

Automatic Evaluation of Welded Joints Using Image Processing on Radiographs  

Microsoft Academic Search

Radiography is frequently used to detect discontinuities in welded joints (porosity, cracks, lack of penetration). Perfect knowledge of the geometry of these defects is an important step which is essential to appreciate the quality of the weld. Because of this, an action improving the interpretation of radiographs by image processing has been undertaken. The principle consists in making a radiograph

Ch. Schwartz

2003-01-01

37

MECHANICAL AND MICROSTRUCTURAL PROPERTIES OF AL 6056 FRICTION STIR WELDED JOINTS  

Microsoft Academic Search

In the present paper, the effects of rotating and welding speed on the mechanical and microstructural properties of Al 6056 butt joints produced by Friction Stir Welding have been analysed. Different welding trials with variable rotating speed of the tool and different welding velocity have been done. The mechanical properties of the welded joints have been evaluated through microhardness measurements

P. Cavaliere; F. W. Panella; A. Squillace

38

Apparatus for maintaining alignment of a shrinking weld joint in an electron-beam welding operation  

DOEpatents

The present invention is directed to an apparatus for automatically maintaining a shrinking weld joint in alignment with an electron beam during an electron-beam multipass-welding operation. The apparatus utilizes a biasing device for continually urging a workpiece-supporting face plate away from a carriage mounted base that rotatably supports the face plate. The extent of displacement of the face plate away from the base is indicative of the shrinkage occuring in the weld joint area. This displacement is measured and is used to move the base on the carriage a distance equal to one-half the displacement for aligning the weld joint with the electron beam during each welding pass.

Trent, Jett B. (Knoxville, TN); Murphy, Jimmy L. (Oak Ridge, TN)

1981-01-01

39

Apparatus for maintaining aligment of a shrinking weld joint in an electron-beam welding operation  

DOEpatents

The invention is directed to an apparatus for automatically maintaining a shrinking weld joint in alignement with an electron beam during an electron-beam multipass-welding operation. The apparatus utilizes a bias means for continually urging a workpiece-supporting face plate away from a carriage mounted base that rotatably supports the face plate. The extent of displacement of the face plate away from the base in indicative of the shrinkage occuring in the weld joint area. This displacement is measured and is used to move the base on the carriage a distance equal to one-half the displacement for aligning the weld joint with the electron beam during each welding pass.

Trent, J.B.; Murphy, J.L.

1980-01-03

40

Effects of Welding Processes and Post-Weld Aging Treatment on Fatigue Behavior of AA2219 Aluminium Alloy Joints  

NASA Astrophysics Data System (ADS)

AA2219 aluminium alloy square butt joints without filler metal addition were fabricated using gas tungsten arc welding (GTAW), electron beam welding (EBW), and friction stir welding (FSW) processes. The fabricated joints were post-weld aged at 175 °C for 12 h. The effect of three welding processes and post-weld aging (PWA) treatment on the fatigue properties is reported. Transverse tensile properties of the welded joints were evaluated. Microstructure analysis was also carried out using optical and electron microscopes. It was found that the post-weld aged FSW joints showed superior fatigue performance compared to EBW and GTAW joints. This was mainly due to the formation of very fine, dynamically recrystallized grains and uniform distribution of fine precipitates in the weld region.

Malarvizhi, S.; Balasubramanian, V.

2011-04-01

41

Crack resistance of the near-weld region of welded joints of titanium and aluminum alloys  

Microsoft Academic Search

We studied the crack resistance Kc (KIc) of the near-weld region of welded joints of VT3-1 and VT14 titanium alloys and AMg6NPP, 12401, and 1420 high-strength aluminum\\u000a alloys under fatigue and static loading. By the methods of fracture mechanics and according to the results of testing cylindrical\\u000a specimens with external circular cracks initiated in the weld metal, fusion zone, zone

N. M. Lebid’; M. S. Kohut

1998-01-01

42

Impact properties of the weld interface in SCM415\\/SCM415 friction welded butt joints  

Microsoft Academic Search

Instrumented Charpy impact testing was carried out at various temperatures from ?196 °C to 200 °C in order to clarify the absorbed energies, impact values, transition temperatures and fracture behaviour at the weld interface of SCM415\\/SCM415 friction welded joints; the results were examined and compared with the impact properties of the base metal. The results may be summarised as follows:1.

C. Kagaya; Y. Kawaguchi; M. Kato

1997-01-01

43

Influence of weld size on fatigue crack growth characteristics of flux cored arc welded cruciform joints  

Microsoft Academic Search

The influence of weld size (L\\/Tp) on fatigue crack growth characteristics of flux cored arc welded (FCAW) cruciform joints, containing lack of penetration (LOP) defect, has been studied. Quenched and tempered (Q&T) steel of ASTM 517 ‘F’ grade has been used as the base material. Fatigue crack growth experiments were carried out in a vertical pulsar under constant amplitude loading

V. Balasubramanian; B. Guha

1999-01-01

44

The influence of welding heat input on submerged arc welded duplex steel joints imperfections  

Microsoft Academic Search

The influence of the heat input submerged arc welding (SAW) of duplex steel UNS S31803 on kind and quantity of welded butt joints defects has been determined. Defects were identified by a radiographic method. For the defectiveness rate in the ratio of quantity negative test results RN to complete radiographic test RC were taken. Radiograms have been classified on the

Jerzy Nowacki; Pawe? Rybicki

2005-01-01

45

Modeling and design of energy concentrating laser weld joints  

SciTech Connect

The application of lasers for welding and joining has increased steadily over the past decade with the advent of high powered industrial laser systems. Attributes such as high energy density and precise focusing allow high speed processing of precision assemblies. Other characteristics of the process such as poor coupling of energy due to highly reflective materials and instabilities associated with deep penetration keyhole mode welding remain as process limitations and challenges to be overcome. Reflective loss of laser energy impinging on metal surfaces can in some cases exceed ninety five percent, thus making the process extremely inefficient. Enhanced coupling of the laser beam can occur when high energy densities approach the vaporization point of the materials and form a keyhole feature which can trap laser energy and enhance melting and process efficiency. The extreme temperature, pressure and fluid flow dynamics of the keyhole make control of the process difficult in this melting regime. The authors design and model weld joints which through reflective propagation and concentration of the laser beam energy significantly enhance the melting process and weld morphology. A three dimensional computer based geometric optical model is used to describe the key laser parameters and joint geometry. Ray tracing is used to compute the location and intensity of energy absorption within the weld joint. Comparison with experimentation shows good correlation of energy concentration within the model to actual weld profiles. The effect of energy concentration within various joint geometry is described. This method for extending the design of the laser system to include the weld joint allows the evaluation and selection of laser parameters such as lens and focal position for process optimization. The design of narrow gap joints which function as energy concentrators is described. The enhanced laser welding of aluminum without keyhole formation has been demonstrated.

Milewski, J.O. [Los Alamos National Lab., NM (United States); Sklar, E. [OptiCad Corp., Santa Fe, NM (United States)

1997-04-01

46

Selection of optimal welding condition for GTA pulse welding in root-pass of V-groove butt joint  

Microsoft Academic Search

In the manufacture of high-quality welds or pipeline, a full-penetration weld has to be made along the weld joint. Therefore,\\u000a root-pass welding is very important, and its conditions have to be selected carefully. In this study, an experimental method\\u000a for the selection of optimal welding conditions is proposed for gas tungsten arc (GTA) pulse welding in the root pass which

Seok-Chul Yun; Jae-Woong Kim

2010-01-01

47

Fatigue classification of welded joints in orthotropic steel bridge decks  

Microsoft Academic Search

This dissertation presents the research into fatigue classifications of welded joints in orthotropic steel bridge decks. These classifications are needed to calculate the fatigue life of these joints and should be included in the design codes. For years bridge design was mainly based on static loading. Due to the development of modern light weight steel structures and extremely increasing traffic

M. H. Kolstein

2007-01-01

48

Correlation of Microstructure and Toughness of the Welded Joint of Pipeline Steel X65  

Microsoft Academic Search

The integrity and the performance of the welded joint of pipelines depend on the microstructure and associated properties.\\u000a The welded joint of steel pipes produced by two-pass double sided submerged arc welding (SAW) consisted of the weld metal\\u000a (WM), heat affected zone (HAZ) and base metal (BM) and as a result the welded joint is characterized by a wide range

Rrahim Maksuti; Hamit Mehmeti; Hartmut Baum; Mursel Rama; Nexhat Çerkini

49

Analysis of martensite transformation behaviour in welded joints of low transformation-temperature materials  

Microsoft Academic Search

In order to improve fatigue strength in welded joints, low transformation-temperature welding wire has been developed in which residual tensile stress can be reduced. In application of the low transformation-temperature welding wire, the prevention of cold cracking without preheating in high strength steel welded joints is expected and examined from the control of residual tensile stress. However, it is expected

Junji Yamamoto; Susumu Meguro; Yoshiki Muramatsu; Naoya Hayakawa; Kazuo Hiraoka

2009-01-01

50

Fatigue of high strength steel joints welded with low temperature transformation consumables  

Microsoft Academic Search

In the present paper constant (CA) and variable amplitude (VA) fatigue testing have been carried out on out-of plane gusset fillet welded high strength steel joints. The joints were welded with conventional weld filler material and martensitic low transformation temperature weld filler, LTT, in order to study the influence of the residual stress on the fatigue strength. Residual stress measurements

Z. Barsoum; M. Gustafsson

2009-01-01

51

Effect of welding processes on AA2219 aluminium alloy joint properties  

Microsoft Academic Search

AA2219 aluminium alloy square butt joints without filler metal addition were fabricated using gas tungsten arc welding (GTAW), electron beam welding (EBW) and friction stir welding (FSW) processes. The effects of three welding processes on the tensile, fatigue and corrosion behaviour were studied. Microstructure analysis was carried out using optical and electron microscopes. The results show that the FSW joints

S. MALARVIZHI; V. BALASUBRAMANIAN

2011-01-01

52

Fatigue crack initiation point in load carrying fillet-welded cruciform joints  

Microsoft Academic Search

Load carrying fillet-welded cruciform joints have two fatigue crack initiation points. They are located in the weld toes and weld roots where high stress concentrations occur. Which of the two serves as the initiation point depends on the weld leg length, plate thickness, and weld penetration, and the mechanism concerned is easily understood. Some experimental results indicate that the fatigue

T. Mori; M. Ichimiya

1999-01-01

53

A study on fatigue crack initiation point of load-carrying fillet welded cruciform joints  

Microsoft Academic Search

Load-carrying fillet welded cruciform joints have two fatigue crack initiating points. These are located at the weld toes and weld roots, where high stress concentrations occur. The location of the fatigue crack initiation depends on the weld size, plate thickness and weld penetration. These mechanisms are easily understood. Previous experimental results have indicated that the fatigue crack originating point is

Shigenobu Kainuma; Takeshi Mori

2008-01-01

54

The effect of weld bead dimensions on the fatigue strength of cruciform joints  

Microsoft Academic Search

The choice of weld bead size in the case of welded cruciform joints can be problematic, especially when the sheets forming the joint are of differing thickness. Technological standards generally recommend a weld bead thickness less than the minimum thickness of the sheets to be joined, whereas structural standards do not envisage any dependency between joint static and fatigue strength

B. Atzori; G. Demelio; B. Rossi

2012-01-01

55

The effect of weld bead dimensions on the fatigue strength of cruciform joints  

Microsoft Academic Search

The choice of weld bead size in the case of welded cruciform joints can be problematic, especially when the sheets forming the joint are of differing thickness. Technological standards generally recommend a weld bead thickness less than the minimum thickness of the sheets to be joined, whereas structural standards do not envisage any dependency between joint static and fatigue strength

B. Atzori; G. Demelio; B. Rossi

2011-01-01

56

Influence of residual stress on stress concentration factor for high strength steel welded joints  

Microsoft Academic Search

In this study, a set of plate-to-plate T and Y joints specimens made from high strength steel plates with yield stress equal to 690MPa is investigated. The joints are fabricated by SMAW welding procedure. Two groups of specimens with different welding procedures are included: one group is composed by the joints with welding completed at ambient temperature and the other

Jin Jiang; Mingshan Zhao

57

A study of mechanical properties of friction welded mild steel to stainless steel joints  

Microsoft Academic Search

The aim of this work is to study mechanical property variation under different friction welding conditions for mild steel stainless steel joints. Yield strength, ultimate tensile strength, percentage elongation of the welded joints and hardness variations across the weld interface have been reported. The integrity of the joints have been investigated using optical microcopy and scanning electron microscopy.

D. Ananthapadmanaban; V. Seshagiri Rao; Nikhil Abraham; K. Prasad Rao

2009-01-01

58

A new fracture mechanics method to predict the fatigue life of welded cruciform joints  

Microsoft Academic Search

The fatigue life of MIG welded cruciform joint failing from root (LOP) region was successfully predicted using new fracture mechanics equations. These equations were developed by combining Paris' law and ?Ki-endurance equation and incorporating an integral factor (Ip) obtained by integrating Paris' equation. In the numerical formulation of the equation, the initiation life (Ni) and propagation life (Np) of the

Bimalendu Guha

1995-01-01

59

Research on fatigue behavior evaluation and fatigue fracture mechanisms of cruciform welded joints  

Microsoft Academic Search

The applications of infrared thermographic method and the relationship between the microstructures and mechanical properties of materials were reviewed. Experimental tests, using the thermographic method, have been carried out in order to evaluate the fatigue behavior of cruciform welded joints subjected to a high mean stress. A good agreement was achieved between the predicted values and those obtained by the

J. L. Fan; X. L. Guo; C. W. Wu; Y. G. Zhao

2011-01-01

60

18. DETAIL VIEW OF A TYPICAL WELDED JOINT BETWEEN THE ...  

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

18. DETAIL VIEW OF A TYPICAL WELDED JOINT BETWEEN THE MAIN GIRDER AND THE FLOOR BEAM, SHOWING THE ATTACHMENT OF A LATERAL BRACING MEMBER AT THIS POINT, SOUTH GIRDER, PANEL 5, LOOKING SOUTH-SOUTHWEST Ryan & Wieskamp - Benton Street Bridge, Spanning Iowa River at Benton Street, Iowa City, Johnson County, IA

61

Low cycle fatigue of welded joints: new experimental approach  

Microsoft Academic Search

To take into account the reduced fatigue strength of welded joints, a reduction life factor applied on fatigue curves (Jf value) was introduced into the RCC-MR [Design and Construction Rules for Mechanical Components of FBR Nuclear Islands, AFCEN, 1993], for the design and construction of fast breeder reactors. To better assess this factor, previous work showed that mechanical behavior of

Yazid Madi; Philippe Matheron; Naman Recho; Philippe Mongabure

2004-01-01

62

Pitting corrosion on weld joints of offshore structure jackets  

SciTech Connect

During underwater inspection, pitting corrosion was observed on weld joints of offshore structure jackets. A detailed investigation was carried out to find the cause of the pitting. Pitting and galvanic corrosion studies and cathodic protection experiments were carried out in synthetic seawater and in 3.5% sodium chloride (NaCl) solution. Field exposure studies also were carried out. Remedial measures are described.

Anto, P.F.

2000-04-01

63

Predicting the Durability of Welded Joints of Thermoplastic Films.  

National Technical Information Service (NTIS)

The investigations were conducted on films of crystalline low density polyethylene (PE n.p.) and amorphous polyvinyl chloride (PVC). The durability of welded joints was determined on a special device, at a temperature of from 20-70C. The tests were conduc...

M. G. Dodin S. B. Ratner

1973-01-01

64

Friction welding of dissimilar metal joints with intermediate layers  

Microsoft Academic Search

Purpose: Metals such as titanium, vanadium, zirconium, niobium, molybdenum and also tantalum and tungsten must be protected at elevated temperatures from the effects of oxygen, nitrogen and hydrogen. For this reason, it is of interest, both from the innovative and practical points of view, to investigate the possibility of using the process of friction welding to produce joints in these

A. Ambroziak; M. Korzeniowski; P. Kustro?

65

Monitoring of weld joint penetration based on weld pool geometrical appearance  

SciTech Connect

Weld joint penetration monitoring and control are fundamental issues in automated welding. A skilled human operator can determine the weld penetration from the geometrical appearance of the weld pool. To emulate this using machine vision, a high-shutter-speed camera assisted with pulsed laser illumination is used to capture the clear image of the weld pool.d The pool boundary is extracted by the developed real-time image processing algorithm. In order to emphasize the emulation of the human operator, general terms, i.e., size, shape and geometrical appearance, are used for the conceptual discussion, whereas more specific terms such as length, width, and rear angles are used in the detailed analysis. In particular, the size will be specified by the pool width and length, and the shape will be defined using the proposed rear angle of the weld pool. The geometrical appearance is described by a combination of the size and shape parameters. To investigate the relationships, which could be complicated, between the weld penetration and different parameters, neural networks are used because of their capability for modeling complicated nonlinear functions. Extensive experiments have been developed to measure the weld penetration from the captured image in 200 ms using the neural network and real-time image processing.

Kovacevic, R.; Zhang, Y.M.; Li, L. [Univ. of Kentucky, Lexington, KY (United States)

1996-10-01

66

Microstructure and Properties of Friction Stir Welded Joints of Al-Mg-Sc Alloy Plates  

Microsoft Academic Search

The hot rolled and cold rolled-annealed plates of Al-Mg-Sc alloys were welded by friction stir welding. The hardness distribution and the tensile properties of welded joints were measured; the relationships between the microstructure and the properties of the welded joints were studied by means of optical microscopy and transmission electron microscopy. The results show that the welding coefficients of two

Peng Yongyi; Yin Zhimin; Lei Xuefeng; Pan Qinglin; He Zhenbo

2011-01-01

67

Analysis of residual stresses and distortions in T-joint fillet welds  

Microsoft Academic Search

T-joint fillet welds are extensively used in ship engineering and bridge structures. Localized heating from the welding process and subsequent rapid cooling induce tensile residual stress near the toe of the T-joint in fillet welds. Welding produces thermal stresses that cause structural distortions, which influence the buckling strength of the welded structures. This study describes the thermal elasto-plastic analysis using

Tso-Liang Teng; Chin-Ping Fung; Peng-Hsiang Chang; Wei-Chun Yang

2001-01-01

68

Reliability assessment and prediction of a fatigue design criterion for the gas-welded joints  

Microsoft Academic Search

Gas metal arc welding is a very important and useful technology in the fabrication of railroad cars and commercial vehicle\\u000a structures. However, since the fatigue strength of the joints welded by gas metal arc welding is considerably lower than that\\u000a of the parent material due to stress concentration and metallurgical changes at the weld, the fatigue-strength assessment\\u000a of welded joints

Seung Yeb Baek; Dong Ho Bae

2010-01-01

69

Hybrid laser-arc welding of galvanized high-strength steels in a gap-free lap-joint configuration  

NASA Astrophysics Data System (ADS)

In order to meet the industry demands for increased fuel efficiency and enhanced mechanical and structural performance of vehicles as well as provided excellent corrosion resistance, more and more galvanized advanced high-strength steels (AHSS) have been used to fabricate automobile parts such as panels, bumpers, and front rails. The automotive industry has shown tremendous interest in using laser welding to join galvanized dual phase steels because of lower heat input and higher welding speed. However, the laser welding process tends to become dramatically unstable in the presence of highly pressurized zinc vapor because of the low boiling point of zinc, around 906°C, compared to higher melting point of steel, over 1500°C. A large number of spatters are produced by expelling the liquid metal from the molten pool by the pressurized zinc vapor. Different weld defects such as blowholes and porosities appear in the welds. So far, limited information has been reported on welding of galvanized high strength dual-phase steels in a gap-free lap joint configuration. There is no open literature on the successful attainment of defect-free welds from the laser or hybrid welding of galvanized high-strength steels. To address the significant industry demand, in this study, different welding techniques and monitoring methods are used to study the features of the welding process of galvanized DP steels in a gap-free lap joint configuration. The current research covers: (i) a feasibility study on the welding of galvanized DP 980 steels in a lap joint configuration using gas tungsten arc welding (GTAW), laser welding, hybrid laser/arc welding with the common molten pool, laser welding with the assistance of GTAW preheating source and hybrid laser-variable polarity gas tungsten arc welding (Laser-VPGTAW) techniques (Chapter 2-4); (ii) a welding process monitoring of the welding techniques including the use of machine vision and acoustic emission technique (Chapter 5); (iii) Modeling of hybrid laser-GTAW as a preheating source welding process of galvanized steels in a gap-free lap joint configuration (Chapter 6). Experimental results demonstrated that completely defect-free lap joints in galvanized high strength steels can be obtained in a gap-free configuration by using the laser welding process with the GTAW torch preheating and hybrid laser-VPGTAW welding technique. Effects of the welding parameters on the weld quality are discussed. The mechanical properties of the welded joints are studied. A machine vision system and an acoustic emission (AE) signal acquisition system are employed to acquire the images of the molten pool and the emitted AE signals on-line. Furthermore, image processing and Short Time Fourier Transform (STFT) techniques are employed to analyze the acquired images of the molten pool and the collected AE signals. The acquisition attempts are composed of (1) monitoring the weld defects by machine vision; (2) monitoring the formation of spatters from the AE signals; (3) detecting the weld modes by the induced plume; and (4) monitoring the instability of the welding process by machine vision. In addition, the numerical results have been validated by the experimental data.

Yang, Shanglu

70

An evaluation of simplified finite element models for spot-welded joints  

Microsoft Academic Search

Spot-welded joints are widely used in automobile structures. Since a typical vehicle contains several thousands of spot welds, it is often not practical in a vehicle structural analysis to model each and every spot-welded joint in detail. As such, simplified structural models have been proposed in the literature for spot-welded joints in large-scale structural computations. To be adequate, a simplified

S. Xu; X. Deng

2004-01-01

71

Influence of the Strength Mismatch of a Narrow Gap Welded Joint of SA508 on the Plastic ? Factor  

NASA Astrophysics Data System (ADS)

In this article, the influence of the strength mismatch of a narrow gap welded joint of SA508 on the ? factor was evaluated. The ? factor is the principal parameter that determines the plastic portion of the J-integral. The specimens for tensile and hardness tests were collected from piping with narrow gap welding and the stress-strain curve and hardness were obtained from those. From these results, the Ramberg-Osgood (R-O) constant was obtained. Also, the finite element analysis was performed with variations in the strength mismatch and the weld width. The ? factor equation considering the strength mismatch and the weld width of a narrow gap welded joint was suggested.

Koo, J. M.; Huh, Y.; Seok, C. S.

2012-11-01

72

Heat and fluid flow in complex joints during gas metal arc welding-Part I: Numerical model of fillet welding  

Microsoft Academic Search

Gas metal arc (GMA) fillet welding is one of the most important processes for metal joining because of its high productivity and amiability to automation. This welding process is characterized by the complicated V-shaped joint geometry, a deformable weld pool surface, and the additions of hot metal droplets. In the present work, a three-dimensional numerical heat transfer and fluid flow

W. Zhang; C.-H. Kim; T. Debroy

2004-01-01

73

Thermal analysis for resistance welding of large-scale thermoplastic composite joints  

SciTech Connect

The need for effective and reliable joining methods continues to grow as the use of thermoplastic composites becomes widespread. It is now possible to join large-scale components with the development of an automated sequential resistance welding process. The thermal history generated by the heating element placed at the interface between adherends determines the quality and performance of the welded joint. This article presents a thermal analysis for the resistance welding of large-scale components that overcomes the limitations of previous models. To simulate welding of the interface, a heat generation term was incorporated that accounts for the Joule heating of graphite fibers in the heating element. A parametric study was conducted to investigate the influence of welding parameters and assess the uniformity of interface temperatures. Components were joined by the resistance welding process to obtain experimental verification. Regions of localized overheating where potential current leakage may occur were identified as a function of process parameters. Insights on promoting more uniform heating for the resistance welding process are discussed. 11 refs.

Holmes, S.T.; Gillespie, J.W. Jr. (Delaware Univ., Newark (United States))

1993-06-01

74

Thermal analysis for resistance welding of large-scale thermoplastic composite joints  

NASA Astrophysics Data System (ADS)

The need for effective and reliable joining methods continues to grow as the use of thermoplastic composites becomes widespread. It is now possible to join large-scale components with the development of an automated sequential resistance welding process. The thermal history generated by the heating element placed at the interface between adherends determines the quality and performance of the welded joint. This article presents a thermal analysis for the resistance welding of large-scale components that overcomes the limitations of previous models. To simulate welding of the interface, a heat generation term was incorporated that accounts for the Joule heating of graphite fibers in the heating element. A parametric study was conducted to investigate the influence of welding parameters and assess the uniformity of interface temperatures. Components were joined by the resistance welding process to obtain experimental verification. Regions of localized overheating where potential current leakage may occur were identified as a function of process parameters. Insights on promoting more uniform heating for the resistance welding process are discussed.

Holmes, Scott T.; Gillespie, John W., Jr.

1993-06-01

75

Thermoelasticity and CCD analysis of crack propagation in AA6082 friction stir welded joints  

Microsoft Academic Search

The advantages of friction stir welding (FSW) process compared to conventional fusion welding technologies have been clearly demonstrated in recent years. In the present study, AA6082 FSW joints were produced by employing different welding parameters. The principal aim of this work is to apply thermoelastic stress analysis (TSA) to study crack propagation characteristics of friction stir welded aluminum sheets, during

P. Cavaliere; A. De Santis; F. Panella; A. Squillace

2009-01-01

76

Effects of weld microstructure on static and impact performance of resistance spot welded joints in advanced high strength steels  

Microsoft Academic Search

Evaluating the impact performance of resistance spot welded joints in advanced high strength steels (AHSS) is critical for their continued integration into the automotive architecture. The effect of strain rate on the joint strength and failure mode is an important consideration in the design of welded structures. Recent results suggest that the failure mode is dependent upon the strength, chemistry,

M. I. Khan; M. L. Kuntz; Y. Zhou

2008-01-01

77

Fatigue life prediction of welded cruciform joints using strain energy density factor approach  

Microsoft Academic Search

The influences of two welding processes, namely, shielded metal arc welding (SMAW) and flux cored arc welding (FCAW), on fatigue life of cruciform joints containing lack of penetration (LOP) defects have been analyzed by using the strain energy density factor (SEDF) approach. Load carrying cruciform joints were fabricated from ASTM 517 ‘F’ grade steel. Fatigue crack growth experiments were carried

V Balasubramanian; B Guha

2000-01-01

78

A fatigue strength evaluation method for load-carrying fillet welded cruciform joints  

Microsoft Academic Search

Fatigue tests were carried out to investigate the fatigue strength of load-carrying fillet welded cruciform joints with weld root failures. Five different weld shapes were considered: an isosceles triangle, two types of scalene triangles, a concave curvature, and a convex curvature. Fatigue crack propagation analyses were also performed on the specimens and on 300 models of the joints with different

Shigenobu Kainuma; Takeshi Mori

2006-01-01

79

Fatigue behaviour of load-carrying, fillet-welded, cruciform joints with plates of different thickness  

Microsoft Academic Search

Large numbers of fillet-welded cruciform joints are extensively employed at the connection zones of steel structural members because of their superiority from consideration of ease of construction and economy. Where this welded cruciform joint becomes a load-carrying type, the fatigue fracture starting point will be either at the weld toe zone, the root zone or both, so the fatigue behaviour

S. Kainuma; Y. Kusumoto; N. Hosomi; I. Kim

2005-01-01

80

Virtual Welded-Joint Design Integrating Advanced Materials and Processing Technologies  

Microsoft Academic Search

The primary goal of this project is to increase the fatigue life of a welded-joint by 10 times and to reduce energy use by 25% through product performance and productivity improvements using an integrated modeling approach. The fatigue strength of a welded-joint is currently the bottleneck to design high performance and lightweight welded structures using advanced materials such as high

Z. Yang; P. Dong; S. Liu; S. Babu; G. Olson; T. DebRoy

2005-01-01

81

Effects of the toe shape of the flash on stress concentration factor in friction welded joints  

Microsoft Academic Search

The authors have previously reported that the fatigue strength of friction welded joints with a flash is markedly affected by the toe shape of the flash caused by friction welding conditions. Accordingly, in this report, the effects of the toe shape of the flash upon the stress concentration factor ? of friction welded joints were examined by means of the

M. Hasegawa; T. Ieda; T. Asada; N. Taki

1997-01-01

82

Mechanical properties evolution during post-welding-heat treatments of double-lap Friction Stir Welded joints  

Microsoft Academic Search

The present study focuses on double-lap Friction Stir Welded (FSW) joints in 2024T3 and 7075T6 aluminium alloys subjected to several post-welding-heat treatments at warm (typical aging) and high temperature (solution range) followed by room temperature deformation (tensile tests). The effect of post-welding-heat treatments on the microstructure and mechanical properties of double lap FSW joints were investigated. Polarized Optical Microscopy (POM)

E. Cerri; P. Leo

2011-01-01

83

Effect of welding parameters on mechanical and microstructural properties of AA6082 joints produced by friction stir welding  

Microsoft Academic Search

The effect of processing parameters on mechanical and microstructural properties of AA6082 joints produced by friction stir welding was analysed in the present study. Different welded specimens were produced by employing a fixed rotating speeds of 1600rpm and by varying welding speeds from 40 to 460mm\\/min. The joints mechanical properties were evaluated by means of tensile tests at room temperature.

P. Cavaliere; A. Squillace; F. Panella

2008-01-01

84

Ultrasonic examination and inservice inspection of LMFBR transition joint welds  

SciTech Connect

Ultrasonic examination and inservice inspection of transition joints between 2 1/4Cr-1Mo and Type 316 stainless steel is described for liquid metal fast breeder reactor applications. The detection of creep fatigue cracks as small as 0.5% of the pipe wall thickness in the 2 1/4Cr-1Mo heat affected zone was demonstrated. The detection of 3% artificial defects in the heat affected zone of the austenitic materials was demonstrated; 8-10% artificial defects in the weld metal were also detectable. These sensitivities required a weld shaved smooth (surface finish better than 250 microinches AA) on both surfaces and the use of signal processing in the austenitic weld metal. The inspection capabilities have been demonstrated in the laboratory and in the U.S. Department of Energy's transient test facility at the Energy Technology Engineering Center.

Day, R.A.

1983-01-01

85

GTAW penetration based on electrode tip location versus weld joint center line  

NASA Astrophysics Data System (ADS)

Gas Tungsten Arc Welding (GTAW) is often the chosen process for final enclosure welds of heat sensitive electrical and electronic product. GTAW is used to produce welds that satisfy design requirements (usually a penetration requirement) and not expose the product to such high heat that would cause unwanted damage. An important variable in the GTAW process is the location of the Electrode tip over the weld joint center line. This study shows the tolerance of positional location over a narrow scope. Using coupons which represent the W88 container weld joint geometry, penetration vs. electrode tip positional location (offset) is investigated. Results indicate a positional location tolerance of +/- 0.008 in. is acceptable. Several different major components (MC's) supporting various weapons programs require low heat input GTA welds. The electrode tip positional location tolerance is determined by each MC's weld joint tolerances and heat sensitivity. For this short study, the weld joint geometry of a container weld was used. These coupons were welded with the specified weld schedule and one additional weld schedule in order to show the relationship based on both travel speed and gap. Multiple coupon welds were made to eliminate error in the results. Within the scope of this research, a positional tolerance of +/- 0.008 in. of the electrode center over the weld joint center is required. For other MC's this tolerance may be tighter or more relaxed depending upon the specific considerations.

Daumeyer, G. J., III

1992-11-01

86

The joint-limits and singularity avoidance in robotic welding  

Microsoft Academic Search

Purpose – The aim of this paper is to develop a redundancy-resolution (RR) algorithm to optimize the joint space trajectory of the six-rotation-axis industrial robot as performing arc-welding tasks. Design\\/methodology\\/approach – The rotation of the tool around its symmetry axis is clearly irrelevant to the view of the task to be accomplished besides some exceptional situations. When performed with a

Liguo Huo; Luc Baron

2008-01-01

87

Effects of flux type of covered electrodes on the fatigue strength of one?pass fillet welded joints  

Microsoft Academic Search

It is generally recognised that the flux type of covered electrodes affects the profile and mechanical properties of welds and may well control the fatigue strength of fillet welded joints. Fillet welded joints, however, have seen few systematic investigations. The purpose of this investigation is to improve the fatigue strength of fillet welded joints through appropriate design of the covered

S. Ota; K. Asai; T. Wada; T. Asakawa

1996-01-01

88

Correlation Between Tensile Strength and Hardness of Electron Beam Welded TC4-DT Joints  

NASA Astrophysics Data System (ADS)

Correlation between tensile strength and hardness for damage-tolerant Ti-6Al-4V (TC4-DT) alloy and its electron beam welded joints was investigated. Yield strength (YS), ultimate tensile strength (UTS) and strain hardening coefficient of base metal and weld metal were obtained using uniaxial tensile tests. Microhardness of the base metal, heat affected zone, and weld metal was measured. Then, the linear correlations among the yield strength, tensile strength, and hardness were proposed. Moreover, correlation between strain hardening coefficient and the ratio of YS to UTS (YS/UTS) was established. The results indicate that microhardness can be used to predict the YS and UTS of the TC4-DT welded joint successfully. In addition, the strain hardening coefficient can be predicted by the YS/UTS. The prediction of strength and strain hardening coefficient is in agreement with the experiments. The correlations are applicable and valuable for the strength prediction of narrow welded fusion zone and heat affected zone based on the microhardness measurement.

Lu, Wei; Shi, Yaowu; Li, Xiaoyan; Lei, Yongping

2013-06-01

89

Effects of weld metal property and fraction on the toughness of welding joints of a 8%Ni 980 MPa high strength steel  

Microsoft Academic Search

This work investigated the variations of Charpy V toughness which was measured in various parts of welding joints of a 980MPa steel. The welding joints were composed of multi-pass weld metal, heat affected zones (HAZs) and base metal. Two types of weld metals, one with inferior toughness and the other with comparable toughness to the base metal, were used to

R. Cao; S. S. Zhu; W. Feng; Y. Peng; F. Jiang; W. S. DU; Z. L. Tian; J. H. Chen

2011-01-01

90

Some investigations on microstructure and mechanical properties of submerged arc welded HSLA steel joints  

Microsoft Academic Search

This paper investigates the influence of the submerged arc welding (SAW) process parameters (welding current and welding speed)\\u000a on the microstructure, hardness, and toughness of HSLA steel weld joints. Attempts have also been made to analyze the results\\u000a on the basis of the heat input. The SAW process was used for the welding of 16 mm thick HSLA steel plates. The

Keshav Prasad; D. K. Dwivedi

2008-01-01

91

Features of the deformation and failure of welded joints with pulsed loading  

Microsoft Academic Search

The kinetics of welded butt joint deformation with pulsed loading are studied by means of solving the dynamic elastoplastic problem. It is shown that under pulsed loading conditions free vibrations arise in a welded joint leading to marked variablesign deformation in the stress concentration zone, i.e. the junction of joint reinforcement with the basic metal. It is established that the

V. I. Kostylev; B. Z. Margolin

1993-01-01

92

Effect of post-weld aging treatment on mechanical properties of Tungsten Inert Gas welded low thickness 7075 aluminium alloy joints  

Microsoft Academic Search

This paper reports the influence of post-weld aging treatment on the microstructure, tensile strength, hardness and Charpy impact energy of weld joints low thickness 7075 T6 aluminium alloy welded by Tungsten Inert Gas (TIG). Hot cracking occurs in aluminium welds when high levels of thermal stress and solidification shrinkage are present while the weld is undergoing various degrees of solidification.

M. Temmar; M. Hadji; T. Sahraoui

2011-01-01

93

Analysis of residual stress on AH32 butt joint by hybrid CO 2 laser-GMA welding  

Microsoft Academic Search

This study has focused on the two-dimensional thermal elasto-plastic analysis to understand and clarify the mechanical phenomena of thermal elasto-plastic behavior on the hybrid welded butt joints. For this, the heat source model for simulation has been determined considering the hybrid welding characteristics. From the results obtained by thermal elasto-plastic analysis, thermal, residual stress characteristics and their production mechanism on

Hee Seon Bang; Han Sur Bang; You Chul Kim; Sung Min Joo

2010-01-01

94

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

95

High temperature low cycle fatigue properties of 316(N) weld metal and 316L(N)\\/316(N) weld joints  

Microsoft Academic Search

In the present paper, cyclic stress evolution and fracture behavior of 316(N) weld metal and 316L(N)\\/316(N) weld joints are reported under strain controlled low cycle fatigue tests. Axial total-strain controlled tests have been conducted at temperatures 773, 823 and 873K with strain amplitudes of ±0.4, ±0.6 and ±1.0%. Though weld metals have shown higher plastic strain accumulation, observed fatigue life

G. V. Prasad Reddy; R. Sandhya; M. Valsan; K. Bhanu Sankara Rao

2008-01-01

96

Literature Review of Stress Intensity Factor Solutions for a Weld Tow Crack in a Fillet Welded Joint.  

National Technical Information Service (NTIS)

A review of Stress Intensity Factor (SIF) solutions, available in the literature, has been carried out for a crack in a fillet welded joint. For two-dimensional weld toe cracks, methods for calculating the SIF solution are discussed. Hybrid techniques, em...

H. L. J. Pang

1991-01-01

97

Diagnostic inspections of butt joints in the oldest steel welded bridges in Poland  

Microsoft Academic Search

In this paper, the structures of 11 steel welded bridges in Poland are shown. These bridges were constructed between 1929 and 1939. In 7 of those bridges, 15 routine photographic X-ray tests of the butt joints were made. From 136 X-ray pictures, the bad condition of the butt welds and the occurrence of internal cracks in the welds were found.

Bernard Wichtowski; Ryszard Pakos

2012-01-01

98

Diagnostic inspections of butt joints in the oldest steel welded bridges in Poland  

Microsoft Academic Search

In this paper, the structures of 11 steel welded bridges in Poland are shown. These bridges were constructed between 1929 and 1939. In 7 of those bridges, 15 routine photographic X-ray tests of the butt joints were made. From 136 X-ray pictures, the bad condition of the butt welds and the occurrence of internal cracks in the welds were found.

Bernard Wichtowski; Ryszard Pakos

2011-01-01

99

Use of Photoelastic Methods to Study the Stressed States of Spot-Welded Joints (Abstract Only).  

National Technical Information Service (NTIS)

The stressed states of full scale visual models of spot welded joints and of an actual spot welded specimen were studied and compared to see whether a visual model can be utilized to analyze stress distribution in welded objects. A photoelastic coating us...

V. F. Kozhevnikov

1987-01-01

100

CRITICAL ANALYSIS OF CURRENT CODES ON FATIGUE DESIGN OF WELDED JOINTS  

Microsoft Academic Search

SUMMARY The aim of this paper is focused on the critical analysis of the recommendations, reported in some current codes, for the fatigue strength assessment of welded structures in ship. This paper collects a large amount of experimental data for fatigue assessment of welded joints, which differ for: base material (steel, aluminium alloys), yield stress, welding technique, geometry (i.e. butt,

Giuseppe Chiofalo; Vincenzo Crupi; Eugenio Guglielmino; Letterio Scibilia

101

FATIGUE BEHAVIOUR OF FRICTION STIR WELDED BUTT JOINTS IN AA6056 ALLOY FOR AIRFRAME APPLICATION  

Microsoft Academic Search

The main objective of the present study is to evaluate the fatigue behaviour of friction stir welded butt joints in 4 mm thick 6056-T4 alloy based on the parent material performance. Welded specimens were produced using the Friction Stir Welding process (FSW) emerged, in 1991, as a promising solid state joining technology. In order to explain the components fatigue behaviour;

S. Lomolino; R. Tovo; J. dos Santos

102

Improved Tig Weld Joint Strength in Aluminum Alloy 2219-T87 by Filler Metal Substitution.  

National Technical Information Service (NTIS)

The results of an investigation on weld joint characteristics of aluminum alloy 2219-T87 are given. Five different alloys were utilized as filler material. The mechanical properties of the joints were determined at ambient and cryogenic temperatures for w...

C. V. Lovoy R. M. Poorman

1972-01-01

103

Modeling and validation of multiple joint reflections for ultra- narrow gap laser welding  

SciTech Connect

The effects of multiple internal reflections within a laser weld joint as a function of joint geometry and processing conditions have been characterized. A computer model utilizing optical ray tracing is used to predict the reflective propagation of laser beam energy focused into the narrow gap of a metal joint for the purpose of predicting the location of melting and coalescence which form the weld. The model allows quantitative analysis of the effects of changes to joint geometry, laser design, materials and processing variables. This analysis method is proposed as a way to enhance process efficiency and design laser welds which display deep penetration and high depth to width aspect ratios, reduced occurrence of defects and enhanced melting. Of particular interest to laser welding is the enhancement of energy coupling to highly reflective materials. The weld joint is designed to act as an optical element which propagates and concentrates the laser energy deep within the joint to be welded. Experimentation has shown that it is possible to produce welds using multiple passes to achieve deep penetration and high depth to width aspect ratios without the use of filler material. The enhanced laser melting and welding of aluminum has been demonstrated. Optimization through modeling and experimental validation has resulted in the development of a laser welding process variant we refer to as Ultra-Narrow Gap Laser Welding.

Milewski, J.; Keel, G. [Los Alamos National Lab., NM (United States); Sklar, E. [Opticad Corp., Santa Fe, New Mexico (United States)

1995-12-01

104

Electron microscopy and microanalysis of steel weld joints after long time exposures at high temperatures  

NASA Astrophysics Data System (ADS)

The structural changes of three trial weld joints of creep resistant modified 9Cr-1Mo steels and low alloyed chromium steel after post-weld heat treatment and long-term creep tests were investigated. Smooth cross-weld specimens ruptured in different zones of the weld joints as a result of different structural changes taking place during creep exposures. The microstructure of the weld joint is heterogeneous and consequently microstructural development can be different in the weld metal, the heat affected zone, and the base material. Precipitation reactions, nucleation and growth of some particles and dissolution of others, affect the strengthening of the matrix, recovery at high temperatures, and the resulting creep resistance. Therefore, a detailed study of secondary phase's development in individual zones of weld joints can elucidate mechanism of cracks propagation in specific regions and the causes of creep failure. Type I and II fractures in the weld metal and Type IV fractures in the fine prior austenite grain heat affected zones occurred after creep tests at temperatures ranging from 525 to 625 °C and under stresses from 40 to 240 MPa. An extended metallographic study of the weld joints was carried out using scanning and transmission electron microscopy, energy-dispersive and wave-dispersive X-ray microanalysis. Carbon extraction replicas and thin foils were prepared from individual weld joint regions and quantitative evaluation of dislocation substructure and particles of secondary phases has been performed.

Jandová, D.; Kasl, J.; Rek, A.

2010-02-01

105

Joint properties of cast Fe-Pt magnetic alloy laser-welded to Co-Cr alloy.  

PubMed

This study investigated the joint properties of Fe-Pt alloy laser-welded to Co-Cr alloy. Cast plates (0.5 x 3.0 x 10 mm) were prepared with Fe-Pt and Co-Cr alloys. Fe-Pt plates were butted against Co-Cr plates and laser-welded using Nd:YAG laser. Control and homogeneously welded specimens were also prepared. Laser welding was performed with and without argon shielding. Tensile testing was conducted, and both fracture force (Ff: N) and elongation (El: %) were recorded. There were no differences in the Ff value between the specimens with and without argon shielding for the welded Fe-Pt/Co-Cr. Lower Ff value of the welded specimen was obtained in the order of Fe-Pt alloy < Fe-Pt/Co-Cr < Co-Cr alloy. The results indicated that Fe-Pt welded to Co-Cr had Ff values between the values of homogeneously welded Fe-Pt and Co-Cr alloys. Argon shielding, on the other hand, had no effect on the weld strength between Fe-Pt and Co-Cr alloys. PMID:16445017

Baba, Naoki; Watanabe, Ikuya; Tanaka, Yasuhiro; Hisatsune, Kunihiro; Atsuta, Mitsuru

2005-12-01

106

Characteristics of Laser Beam and Friction Stir Welded AISI 409M Ferritic Stainless Steel Joints  

NASA Astrophysics Data System (ADS)

This article presents the comparative evaluation of microstructural features and mechanical properties of friction stir welded (solid-state) and laser beam welded (high energy density fusion welding) AISI 409M grade ferritic stainless steel joints. Optical microscopy, microhardness testing, transverse tensile, and impact tests were performed. The coarse ferrite grains in the base material were changed to fine grains consisting duplex structure of ferrite and martensite due to the rapid cooling rate and high strain induced by severe plastic deformation caused by frictional stirring. On the other hand, columnar dendritic grain structure was observed in fusion zone of laser beam welded joints. Tensile testing indicates overmatching of the weld metal relative to the base metal irrespective of the welding processes used. The LBW joint exhibited superior impact toughness compared to the FSW joint.

Lakshminarayanan, A. K.; Balasubramanian, V.

2012-04-01

107

Predicting fatigue crack growth rate in a welded butt joint: The role of effective R ratio in accounting for residual stress effect  

Microsoft Academic Search

A simple and efficient method is presented in this paper for predicting fatigue crack growth rate in welded butt joints. Three well-known empirical crack growth laws are employed using the material constants that were obtained from the base material coupon tests. Based on the superposition rule of the linear elastic fracture mechanics, welding residual stress effect is accounted for by

G. Servetti; X. Zhang

2009-01-01

108

Investigation of the fatigue strength of the welded joints treated by TIG dressing  

Microsoft Academic Search

The fatigue fracture of structural details subjected to cyclic loads mostly occurs at a critical cross section with stress concentration. The welded joint is particularly dangerous location because of sinergetic harmful effects of stress concentration, tensile residual stresses, deffects, microstructural heterogeneity. Because of these reasons many methods for improving the fatigue resistance of welded joints are developed. Significant increase in

Zoran D. Perovi?

2007-01-01

109

A study on mechanical and microstructure characteristics of the STS304L butt joints using hybrid CO 2 laser-gas metal arc welding  

Microsoft Academic Search

In order to examine mechanical characteristics of the stainless steel (STS304L) hybrid welded butt joints, two-dimensional thermal elasto-plastic analysis has been carried out. To this end, a 2D simulation model has been developed considering hybrid welding features. Based on thermal history data obtained from this heat source model, the residual stress distribution in weld metal (WM), heat affected zone (HAZ)

Hee Seon Bang; Han Sur Bang; You Chul Kim; Ik Hyun Oh

2011-01-01

110

Numerical simulation of creep damage for low alloy steel welded joint considering as-welding residual stress  

Microsoft Academic Search

A model to calculate the welding temperature and residual stress was built using finite element code ABAQUS, and a subroutine of creep damage was also developed. Based on the coupling of welding residual stress and creep damage, the welding residual stress and creep damage of a tube made of Cr5Mo steel were simulated. This method can obtain the distributions of

Guodong Zhang; Changyu Zhou; Zhaoxi Wang; Fei Xue; Yanfen Zhao; Lu Zhang; Yan Liu

111

Type IV Creep Damage Behavior in Gr.91 Steel Welded Joints  

NASA Astrophysics Data System (ADS)

Modified 9Cr-1Mo steel (ASME Grade 91 steel) is used as a key structural material for boiler components in ultra-supercritical (USC) thermal power plants at approximately 873 K (600 °C). The creep strength of welded joints of this steel decreases as a result of Type IV creep cracking that forms in the heat-affected zone (HAZ) under long-term use at high temperatures. The current article aims to elucidate the damage processes and microstructural degradations that take place in the HAZ of these welded joints. Long-term creep tests for base metal, simulated HAZ, and welded joints were conducted at 823 K, 873 K, and 923 K (550 °C, 600 °C, and 650 °C). Furthermore, creep tests of thick welded joint specimens were interrupted at several time steps at 873 K (600 °C) and 90 MPa, after which the distribution and evolution of creep damage inside the plates were measured quantitatively. It was found that creep voids are initiated in the early stages (0.2 of life) of creep rupture life, which coalesce to form a crack at a later stage (0.8 of life). In a fine-grained HAZ, creep damage is concentrated chiefly in an area approximately 20 pct below the surface of the plate. The experimental creep damage distributions coincide closely with the computed results obtained by damage mechanics analysis using the creep properties of a simulated fine-grained HAZ. Both the concentration of creep strain and the high multiaxial stress conditions in the fine-grained HAZ influence the distribution of Type IV creep damage.

Hongo, Hiromichi; Tabuchi, Masaaki; Watanabe, Takashi

2012-04-01

112

Fatigue strength of welded joints in 6N01 aluminium alloy extrusions  

Microsoft Academic Search

In this paper, the fatigue strength of welded joints in 6N01 aluminium alloy extrusions is discussed. Low copper content (?0.02%) alloys were chosen, considering corrosion resistance in sea water. Two series of specimens were prepared. One had two longitudinal stiffeners welded on both sides of the main plate (L?TYPE), and the other a non?load carrying fillet welded cruciform joint (T?TYPE).

K. Matsuoka; S. Chiaki; T. Uemura; K. Kamata

1994-01-01

113

Comparison of the Stress Intensity Factor of Load-Carrying Cruciform Welded Joints with Different Geometries  

Microsoft Academic Search

The investigation of fatigue strength needs an accurate solution and reliable values of the stress intensity factor (SIF).\\u000a In this study, SIF of load-carrying cruciform welded joints has been evaluated using finite element method (FEM), and compared\\u000a with the available solutions from literature. Load-carrying cruciform welded joints with isosceles triangles and non-isosceles\\u000a triangle fillet weld shapes were considered and have

A. Al-Mukhtar; H. Biermann; S. Henkel; P. Hübner

2010-01-01

114

Fatigue strength improvement of MIG-welded joint by shot peening  

Microsoft Academic Search

In this study, the effect of controlled shot peening (CSP) treatment on the fatigue strength of an ASTM A516 grade 70 carbon steel MIG-welded joint has been studied quantitatively. Metallurgical modifications, hardness, elemental compositions, and internal discontinuities, such as porosity and inclusions found in treated and untreated fusion welded joints, were characterized. The fatigue results of as-welded and peened skimmed

Nur Azida Che Lah; Aidy Ali

2011-01-01

115

Corrosion behavior of welded joints of austenitic 06Kh18G9N5AB steel  

SciTech Connect

The corrosion behavior of homogeneous and heterogeneous (with 12Kh18N10T and St 3 steels) welded joints of 06Kh18G9N5AB steel in boiling chloride and alkali solutions and in NACE solution is investigated. The influence of welding methods and electrodes on the structure and distribution of alloying elements in the areas around the welded joints is demonstrated.

Melekhov, R.K.; Chumalo, G.V.; Pavlov, V.N.; Yurchak, A.V. [Karpenko Physicomechanical Institute, L`viv (Ukraine)

1994-03-01

116

Fatigue tests on welded tubular t-joints with equal brace and chord diameters  

SciTech Connect

This paper describes the results of fatigue tests which have been carried out on welded tubular T-joints with equal brace and chord diameters (BETA = 1) as part of the United Kingdom Offshore Steels Research Programme. Specimens with chord diameters of 168mm and 457mm have been tested. This geometry is not covered by the majority of parametric equations available for the prediction of stress concentration factors in tubular joints. The present results show that the SCF in these joints is dependent on the weld profile. The fatigue results show an influence of specimen size and are adequately covered by existing design curves. Of particular interest are the fatigue crack developments in the 457mm diameter joints, which show extensive weld inter-run cracking on many specimens in preference to weld toe cracking. This suggests that weld toe grinding alone may not be effective in improving fatigue strength for joints of this geometry.

Wylde, J.G.

1983-05-01

117

Mechanical and technological analysis of AISI 304 butt joints welded with capacitor discharge process  

Microsoft Academic Search

In the present work, the capacitor discharge welding process (CDW) applied on AISI 304 circular bars was studied. The CDW process is essentially an electrical resistance welding technology, realized through current pulses of high intensity and discharged by large capacitors; the process allows to reduce stress concentration effects at the weld toe, obtaining thin welds and achieve good material integrity.CDW

V. Dattoma; F. Palano; F. W. Panella

2010-01-01

118

Microstructural changes in welded joints of 316 SS by dual-ion irradiation  

NASA Astrophysics Data System (ADS)

As a part of the activity to establish joining methods to fabricate in-vessel components and to evaluate their performance under fusion environment, microstructural evolution was studied by means of the dual-ion irradiation method. The base material used in this study was solution annealed 316 stainless steel. Welded joints were made by the tungsten inert gas (TIG) welding method and electron beam (EB) welding method. For the prospective improvement of swelling in welded joints, modified TIG or EB welding procedures utilizing titanium or nickel foil insertions were investigated. TEM disk specimens from various positions of welded joints were irradiated to 25 dpa at 673, 773 and 873 K. He/dpa ratio in Ni/He dual-ion irradiation was 15 appm He/dpa. The present results indicate some concern about the microstructures which result in the fusion zone and heat affected zones.

Kohyama, A.; Kohno, Y.; Baba, K.; Katoh, Y.; Hishinuma, A.

1992-09-01

119

The Diagnostic Method of Inner Parts of Welded Joints at Nuclear Power Plant  

NASA Astrophysics Data System (ADS)

There is no possibility to check any inner part at real welded joint at nuclear power station (NPS) during operation because any destructive test cannot be used. In practice there is checked surface of weld. There are used four methodical instructions for the check of real welds: 1. The visual inspection, 2. The measurement of hardness, 3. The chemical composition checking and 4. The microstructure replica analysis. It is necessary to know how these information of weld surface are in accordance with characteristics of inner parts of weld. If there is not any difference between surface weld microstructure and internal weld microstructure of experimental weld it is supposed to that there is not any difference in other measured properties of welds. If is changed structural characteristics of microstructure, it is changed also hardness, chemical analysis etc. It was observed that the microstructure of real welds is almost the same with simulated weld and also the surface microstructure of experimental weld is in accordance with microstructure of inner parts of this weld. It can be supposed extension of lifetime of NPS if there is not any difference between replicas microstructure taken after six year operation of NPS and microstructure of inner parts of simulated weld is almost the same with surface microstructure.

Bednarova, O.; Janovec, J.

2010-06-01

120

Fatigue resistance of manual electric arc welding joints in high-strength 14Kh2GMR steel  

Microsoft Academic Search

The results are presented of testing the fatigue resistance of welded cruciform specimens with a symmetric cycle for 2·106 cycles. The results show that the endurance of welded joints produced with ANP-6P electrodes is 2.5–3 times longer than that of the welded joints produced with ANP-2 and UONI-13\\/45 electrodes. At high fatigue strength values of the welded joints produced with

L. I. Mikhodui; S. B. Kasatkin; V. D. Poznyakov; D. M. Kogut

1990-01-01

121

Heat and fluid flow in complex joints during gas metal arc welding-Part I: Numerical model of fillet welding  

NASA Astrophysics Data System (ADS)

Gas metal arc (GMA) fillet welding is one of the most important processes for metal joining because of its high productivity and amiability to automation. This welding process is characterized by the complicated V-shaped joint geometry, a deformable weld pool surface, and the additions of hot metal droplets. In the present work, a three-dimensional numerical heat transfer and fluid flow model was developed to examine the temperature profiles, velocity fields, weld pool shape and size, and the nature of the solidified weld bead geometry during GMA fillet welding. The model solved the equations of conservation of mass, momentum, and energy using a boundary fitted curvilinear coordinate system. Apart from the direct transport of heat from the welding arc, additional heat from the metal droplets was modeled considering a volumetric heat source. The deformation of the weld pool surface was calculated by minimizing the total surface energy. Part I of this article is focused on the details of the numerical model such as coordinate transformation and calculation of volumetric heat source and free surface profile. An application of the model to GMA fillet welding of mild steel is described in an accompanying article (W. Zhang, C.-H. Kim and T. DebRoy, J. Appl Phys. 95, 5220 (2004)).

Zhang, W.; Kim, C.-H.; Debroy, T.

2004-05-01

122

Microstructure and Tensile Properties of Submerged Arc Welded 1.25Cr0.5Mo Steel Joints  

Microsoft Academic Search

This article describes the effect of heat input (controlled by welding current and welding speed) on the microstructure and tensile properties of high strength low alloy (HSLA) steel weldments produced by submerged arc welding (SAW). The SAW process was used for welding of 16 mm thick 1.25Cr-0.5Mo steel (ASTM A387 gr-11) plates. The weld joints were prepared by varying the welding

Keshav Prasad; D. K. Dwivedi

2008-01-01

123

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

124

Modeling and validation of multiple joint reflections for ultra- narrow gap laser welding  

Microsoft Academic Search

The effects of multiple internal reflections within a laser weld joint as a function of joint geometry and processing conditions have been characterized. A computer model utilizing optical ray tracing is used to predict the reflective propagation of laser beam energy focused into the narrow gap of a metal joint for the purpose of predicting the location of melting and

J. Milewski; G. Keel; E. Sklar

1995-01-01

125

Modelling the fatigue crack growth in friction stir welded joint of 2024-T351 Al alloy  

Microsoft Academic Search

In this work the fatigue crack propagation within the friction stir welded (FSW) joint of 2024-T351 Al alloy is studied as well as fatigue lifetime of the joint using Walker and Nicholls models. The FSW joint is characterised in terms of the residual stress (using the hole drilling technique), material, and cyclic properties. The material surface is polished in order

A. F. Golestaneh; Aidy Ali; M. Zadeh

2009-01-01

126

A Finite Element Calculation of Stress Intensity Factors of Cruciform and Butt Welded Joints for Some Geometrical Parameters  

Microsoft Academic Search

With welded joints, stress concentrations occur at the weld toe and at the weld root, which make these regions the points from which fatigue cracks may initiate. To calculate the fatigue life of welded structures and to analyze the progress of these cracks using fracture mechanics technique requires an accurate calculation of the stress intensity factor SIF. The existing SIFs

A. M. Al-Mukhtar; S. Henkel; H. Biermann; P. Hübner; M. S. Samhouri; A. Al-Ghandoor; R. H. Fouad; M. A. Ali; J. Chebil; G. Noel; M. Mesbah; M. Deriche; A. Omran; M. Bayoumi; A Kassem; G. El-Bayoumi

2009-01-01

127

Mechanical properties of duplex steel welded joints in large-size constructions  

Microsoft Academic Search

Thick panels measuring 9.5, 14.5, and 18.5 mm made of UNS S31803 duplex steel were tested for welding with the use of powder wire. The target task consisted in determination of the impact of the welding process with an increased root gap on the mechanical properties of joints, as compared with the properties achieved by welding with a 6-mm threshold distance

Jerzy Nowacki; Piotr Zaj?c

2011-01-01

128

Mechanical properties of duplex steel welded joints in large-size constructions  

Microsoft Academic Search

Thick panels measuring 9.5, 14.5, and 18.5 mm made of UNS S31803 duplex steel were tested for welding with the use of powder wire. The target task consisted in determination of the impact of the welding process with an increased root gap on the mechanical properties of joints, as compared with the properties achieved by welding with a 6-mm threshold distance

Jerzy Nowacki; Piotr Zaj?c

2012-01-01

129

Fatigue Behavior of Welded Joints in a Ferritic Stainless Steel SUS444  

Microsoft Academic Search

Fatigue behavior was studied on welded joints of a ferritic stainless steel, SUS444. Push-pull fatigue tests were conducted using plate specimens with the weld zone at the center of gauge section. Fatigue crack propagation (FCP) tests were also conducted using two types of CT-specimens with a starter notch in the heat-affected zone (HAZ) and in the weld metal. The fatigue

Masaki NAKAJIMA; Masayuki AKITA; Keiro TOKAJI; Yousuke TAKAI

130

Fatigue failure characterisation of resistance-welded thermoplastic composites skin\\/stringer joints  

Microsoft Academic Search

An experimental investigation characterising the fatigue failure mechanisms of resistance-welded thermoplastic composites skin\\/stringer joints is presented. Unidirectional (UD) and quasi-isotropic adherends were welded using stainless steel meshes as heating elements. The specimen geometry consisted of a flange laminate, representing a stringer, welded onto a skin laminate. In order to avoid current leakage to the electrically conductive adherends, a ceramic-coated heating

M. Dubé; P. Hubert; A. Yousefpour; J. Denault

2009-01-01

131

Microstructural zones and tensile characteristics of friction stir welded joint of TC4 titanium alloy  

Microsoft Academic Search

TC4 titanium alloy was friction stir welded using a W-Re pin tool, and the defect-free weld was produced with proper welding parameters. The joint consists of stir zone, heat affected zone and base material. The stir zone is characterized by equiaxed dynamically recrystallized a phases and transformed ? phases with fine a+? lamellar microstructure. The microstructure of the heat-affected zone

Hui-jie LIU; Li ZHOU

2010-01-01

132

Influences of welding processes on fatigue life of cruciform joints of pressure vessel grade steels containing LOP defects  

Microsoft Academic Search

The influences of two welding processes, namely, shielded metal arc welding (SMAW) and flux cored arc welding (FCAW), on fatigue life of cruciform joints, containing lack of penetration (LOP) defects, have been studied. Load carrying cruciform joints were fabricated from high strength, quenched and tempered steels of pressure vessel (ASTM 517 ‘F’) grade. Fatigue crack growth experiments were carried out

V Balasubramanian; B Guha

2000-01-01

133

A simplified fatigue assessment method for high quality welded cruciform joints  

Microsoft Academic Search

The primary goal of this study was to develop an equation relating the geometric parameters to fatigue strength which can be used is routine design assessment. To attain this, the influence of local geometrical weld variations on the fatigue strength of non-load-carrying cruciform fillet welded joints were systematically studied using plane strain linear elastic fracture mechanics (LEFM). The effects of

T. Nykänen; G. Marquis; T. Björk

2009-01-01

134

Analysis of non-loading carrying fillet welds joint using SGBEM  

Microsoft Academic Search

Fatigue failure is probably the most common type of failure in welded construction. It is usually initiates at a stress concentration area within the structure. The fatigue behavior of non-load carrying cruciform fillet welded joint has been studied extensively using boundary element method. The symmetric boundary element method for multiple cracks problem is derived using Betti's reciprocal theorem in auxiliary

Xu Kai; Lu Yong; S. T. Lie

2004-01-01

135

Comparison of fatigue life for T and cruciform welded joints with different combinations of geometrical parameters  

Microsoft Academic Search

The fatigue life for T and cruciform welded joints containing different extents of lack of root penetration was calculated for different combinations of geometrical parameters, including thicknesses up to 45 mm, by integration of the Paris law and use of stress intensity factor solutions calculated previously. The effect of attachment and main plate thickness, weld leg length and initial lack

A. Khodadad Motarjemi; A. H Kokabi; F. M Burdekin

2000-01-01

136

Fatigue life improvement of AISI 304L cruciform welded joints by cryogenic treatment  

Microsoft Academic Search

Existing theories and reported practical experience show that cryogenic processing greatly increases abrasion resistance and contact fatigue resistance of some metals and alloys. In the present work, an attempt has been made to investigate the effect of cryogenic treatment on the axial fatigue performance of fillet welded cruciform joints of AISI 304L stainless steel, which failed in the weld metal.

P Johan Singh; B Guha; D. R. G Achar

2003-01-01

137

Microstructures and mechanical properties of resistance spot welded magnesium alloy joints  

Microsoft Academic Search

The resistance spot welded magnesium alloy joints consist mainly of weld nugget and heat-affected zone (HAZ). The nugget contains two different structures, the cellular-dendritic structure at the edge of the nugget and the equiaxed dendritic structure in the center of the nugget. The structure transition is attributed to the changes of solidification conditions. In HAZ, the grain boundary melting occurred

D. Q. Sun; B. Lang; D. X. Sun; J. B. Li

2007-01-01

138

TEM study of microstructure in explosive welded joints between Zircaloy-4 and stainless steel.  

National Technical Information Service (NTIS)

The microstructure of explosive welded joints between Zircaloy-4 and 18/8 stainless steel has been investigated by transmission electron microscopy (TEM). The metallurgical bonding was achieved by combining effect of diffusion and local melting when the e...

Zhou Hairong Zhou Bangxin

1996-01-01

139

Crack propagation analysis of welded thin-walled joints using boundary element method  

Microsoft Academic Search

Tube-to-plate nodal joints under cyclic bending are widely used in the road transport and agricultural industry. The square\\u000a hollow sections (SHS) used in these constructions are thin-walled and cold formed, and they have thicknesses of less than\\u000a 4?mm. Some fatigue failures have been observed. The weld undercut may affect the fatigue life of welded tubular joints especially\\u000a for thin-walled sections.

F. R. Mashiri; Xiao-Ling Zhao; P. Grundy

2000-01-01

140

Fatigue analysis of non-load-carrying fillet welded cruciform joints  

Microsoft Academic Search

The goal of this investigation was to study the effect of local geometrical variations of the weld on the fatigue strength. Therefore the fatigue behaviour of non-load-carrying cruciform fillet welded joint under tensile loading has been studied parametrically. Several two-dimensional (2D) finite element models of the joint were analysed using plane strain linear elastic fracture mechanics (LEFM) calculations in order

T. Nykänen; G. Marquis; T. Björk

2007-01-01

141

A simple estimating method for reduction of welding residual stresses in thick welded joint from stress-relief annealing. Part 2: The characteristics of reduction of welding residual stresses in very thick joints during SR treatment  

Microsoft Academic Search

Stress-relief annealing (SR treatment) is often applied to relieve welding residual stresses in the fabrication process of pressure vessels, etc. This study aims at development of an efficient method as simple as hand calculation to estimate reduction of residual stresses of very thick welded joint by SR treatment. In the first report, an estimating method was developed for relaxation tests,

K. Nakacho; Y. Ueda

1999-01-01

142

Effect of External Geometry on Fatigue Behavior of Welded Joints.  

National Technical Information Service (NTIS)

Fatigue tests were conducted on simulated butt-welded specimens of ordinary structural grade steel with the simulated 'weld reinforcement' machined from base metal. The profile of the weld reinforcement was controlled by varying the radius at the toe of t...

W. W. Sanders A. T. Derecho W. H. Munse

1964-01-01

143

The joint properties of brass plates by friction stir welding  

Microsoft Academic Search

Brass materials widely used as engineering materials in industry because of their high strength, high corrosion resistance, high electrical and thermal conductivity. They are easily shaped and they possess nice appearance. However, it is difficult to fusion welding of brasses. The main problem of these alloys in fusion welding is the evaporation of the zinc during the welding process. After

Cemal Meran

2006-01-01

144

Structure and mechanical properties of the welded joints of large-diameter pipes  

NASA Astrophysics Data System (ADS)

The structure and mechanical properties of the technological welded joints of large-diameter pipes of strength class K60 produced by two companies are studied. Along with standard mechanical properties (?0.2, ?u, ?, ?), specific work of deformation a (tensile toughness) and true rupture strength S f are estimated from an analysis of the stress-strain diagrams constructed in true coordinates. The mechanical behavior is found to be different for samples cut from different zones of a welded joint (central weld, heat-affected zone, and base metal). The mutual correlation between parameters a, S f, and impact toughness KCV is considered.

Khotinov, V. A.; Arabei, A. B.; Pyshmintsev, I. Yu.; Farber, V. M.

2013-05-01

145

Study on electron beam weld joints between pure vanadium and SUS316L stainless steel  

NASA Astrophysics Data System (ADS)

The mechanical and metallographical properties of the electron beam weld joints between pure vanadium (V) and SUS316L austenitic stainless steel and the effect of post-welding heat treatment (PWHT) at 873 and 1273 K for 1 h on these properties were investigated. The electron beam was shifted by 0.2 mm (EB02S), 0.4 mm (EB04S), and 0.6 mm (EB06S) on the SUS316L side. No significant defects (e.g., pores, macro-cracks, or micro-cracks) were observed in the as-welded EB02S and EB04S joints, whereas a non-welded region was formed in the as-welded EB06S joint. Much higher hardness was observed in the weld metal (WM) of the as-welded EB02S and EB04S joints than in the base metals (BMs), which might be attributed to solution hardening. A significant increment in the hardness of the WM of EB02S joint occurred due to the PWHT at 873 and 1273 K, which might be attributed to solution hardening and formation of Ni2V3 and NiV3 precipitates. Almost no change in the hardness due to the PWHT at 873 and 1273 K occurred in the WM of the EB04S joint. The interlayer was formed at the edge of the WM of the V side only in the post-welding heat-treated EB04S joint. The interlayer showed much higher hardness than the BMs and WM, which might be attributable to solution hardening, formation of ? phase of the Fe-V system, and formation of Ni2V3 and NiV3 precipitates.

Nogami, Shuhei; Miyazaki, Jumpei; Hasegawa, Akira; Nagasaka, Takuya; Muroga, Takeo

2013-11-01

146

Fatigue strength of cruciform and other fillet welded joints in aluminum alloys  

NASA Astrophysics Data System (ADS)

ESDU 92017 presents the results extracted from the literature of nearly 850 constant amplitude loading fatigue tests. Joints were load-carrying and non load-carrying transverse cruciform, load-carrying and non load-carrying transverse and longitudinal cover plate, and single- and double-fillet lap under axial loading. Data are included on fillet welded attachments under axial loading and tee fillet welded joints under either axial or bending loading. The effect of mean stress is shown for cruciform and cover plate joints, and the effect of post-weld treatments (shot peening and tungsten-inert-gas dressing) is shown for some cover plate joints. The joints were in twelve alloys in the 5000, 6000, or 7000 series with fillers in the 5000 series. All welding process variables and geometries are detailed and the location of failure is indicated. A table summarizes fatigue strengths at lives of a million and 10 million cycles for stress ratios of zero and -1. Summary graphs compare the scatter bands for all joint types in all materials and also mean fatigue strength curves for all types in alloy 5083. A graph also shows the influence of parent alloy tensile strength on welded joint fatigue strength.

1992-08-01

147

Details of the ElectroMechanical (E\\/M) Impedance Health Monitoring of Spot-Welded Structural Joints  

Microsoft Academic Search

Health monitoring of structural joints is a major concern of the engineering community. Among joining techniques, spot- welding play a major role. Spot welding is the traditional method of assembly for steel-based automotive structures, while spot-welding of aluminum is being considered for future vehicular structures. Though spot welding of steel is well researched and understood, the spot-welding of aluminum still

Victor Giurgiutiu; Anthony Reynolds; Craig A. Rogers

148

Evaluation of friction welded joint performance by recognition of burr shape (in the case of A5056 aluminum alloy)  

Microsoft Academic Search

A strong correlation is believed to exist between the burr shape and friction welded joint performance. The possibility of evaluating welded joint performance from burr shape, which is a non-destructive inspection method, will lead to its application in evaluating joint performance. Thus, in this study burr shape data is fed into an image processing equipment and a precise measurement of

K. Ogawa; G. Kawai; K. Sakurai; H. Yamaguchi; Y. Takashima

1995-01-01

149

Analysing the influences of weld size on fatigue life prediction of FCAW cruciform joints by strain energy concept  

Microsoft Academic Search

The effect of weld size on fatigue life of flux cored arc welded (FCAW) cruciform joints containing lack of penetration (LOP) defect has been analysed by using the strain energy density factor (SEDF) concept. Moreover, new fracture mechanics equations have been developed to predict the fatigue life of the cruciform joints. Load carrying cruciform joints were fabricated from ASTM 517

V Balasubramanian; B Guha

1999-01-01

150

Comparison of the stress intensity factor of T and cruciform welded joints with different main and attachment plate thickness  

Microsoft Academic Search

The present study compares the stress intensity factor of T and cruciform welded joints containing Lack of Penetration defects and gives new results in the form of parametric equation coefficients for the T joint case. Cruciform and T welded joints with equal and unequal attachment and main plate thickness have been analysed by the finite element method. For the T

A. Khodadad Motarjemi; A. H. Kokabi; A. A. Ziaie; S. Manteghi; F. M. Burdekin

2000-01-01

151

Fatigue life assessment of load-carrying fillet-welded cruciform joints inclined to uniaxial cyclic loading  

Microsoft Academic Search

This study examines, the relationship between the direction of an applied stress cycle and the fatigue behaviour of load-carrying fillet-welded cruciform joints with weld root cracks, and presents the fatigue life assessment of the joints. Fatigue tests were performed on four sets of cruciform joints inclined at an angle of 0, 15, 30, or 45° to the normal direction of

In-Tae Kim; Shigenobu Kainuma

2005-01-01

152

Resistance of Welded Joints in High Temperature Hastelloy N-Type Nickel Alloy to Hot Crack Formation (Abstract Only),  

National Technical Information Service (NTIS)

The topography and morphology of hot cracks in welded joints of a high temperature nickel alloy in the nickel chromium molybdenum system was refined. The crack resistance of welded joints in an experimental Hastelloy N alloy was studied. Butt joints of ri...

K. A. Yushchenko V. N. Lipodayev M. V. Belchuk G. N. Gordan O. V. Novichkova

1987-01-01

153

A Study of Microstructure and Mechanical Properties of Grade 91 Steel A-TIG Weld Joint  

NASA Astrophysics Data System (ADS)

In the present study, A-TIG welding was carried out on grade 91 steel plates of size 220 × 110 × 10 mm using the in-house developed activated flux to produce butt-joints. The room-temperature impact toughness of the A-TIG as-welded joint was low due to the presence of untempered martensite matrix despite the low microinclusion density caused by activated flux and also low ?-ferrite (<0.5 %) content. Toughness after postweld heat treatment (PWHT) at 760 °C-2 h was 20 J as against the required value of 47 J as per the specification EN: 1557:1997. However, there was a significant improvement in impact toughness after PWHT at 760 °C for 3 h. The improvement in toughness was attributed to softening of martensite matrix caused by precipitation of carbides due to tempering reactions. The precipitates are of type M23C6, and they are observed at grain boundary as well as within the grains. The A-TIG-processed grade 91 steel weld joint was found to meet the toughness requirements after PWHT at 760 °C-3 h. Observations of fracture surfaces using SEM revealed that the as-welded joint failed by brittle fracture, whereas post-weld heat-treated weld joints failed by decohesive rupture mode.

Arivazhagan, B.; Vasudevan, M.

2013-09-01

154

Design of a welded joint for robotic, on-orbit assembly of space trusses  

NASA Astrophysics Data System (ADS)

In the future, some spacecraft will be so large that they must be assembled on-orbit. These spacecraft will be used for such tasks as manned missions to Mars or used as orbiting platforms for monitoring the Earth or observing the universe. Some large spacecraft will probably consist of planar truss structures to which will be attached special purpose, self-contained modules. The modules will most likely be taken to orbit fully outfitted and ready for use in heavy-lift launch vehicles. The truss members will also similarly be taken to orbit, but most unassembled. The truss structures will need to be assembled robotically because of the high costs and risks of extra-vehicular activities. Some missions will involve very large loads. To date, very few structures of any kind have been constructed in space. Two relatively simple trusses were assembled in the Space Shuttle bay in late 1985. Here the development of a design of a welded joint for on-orbit, robotic truss assembly is described. Mechanical joints for this application have been considered previously. Welded joints have the advantage of allowing the truss members to carry fluids for active cooling or other purposes. In addition, welded joints can be made more efficient structurally than mechanical joints. Also, welded joints require little maintenance (will not shake loose), and have no slop which would cause the structure to shudder under load reversal. The disadvantages of welded joints are that a more sophisticated assembly robot is required, weld flaws may be difficult to detect on-orbit, the welding process is hazardous, and welding introduces contamination to the environment. In addition, welded joints provide less structural damping than do mechanical joints. Welding on-orbit was first investigated aboard a Soyuz-6 mission in 1969 and then during a Skylab electron beam welding experiment in 1973. A hand held electron beam welding apparatus is currently being prepared for use on the MIR space station. welding. &A low gravity environment has been found to have very minor effects on the welding processes appropriate for this application. This is based on tests run on-orbit as well as low gravity environments achieved by flying aircraft in parabolic trajectories. It appears that a modified form of gas tungsten arc welding (GTAW) will be most appropriate for welding together structures on-oribt. *The process has been modified to work in a vacuum by providing gas to the arc zone by means of a hollow tungsten electrode with special shielding. -A commercial tube welding head has been successfully modified for use on-orbit with a gas leakage rate of approximately 2.5 liters/min. To develop as realistic a joint as possible, a specific truss structure was selected on which to base the design. The structure considered was based on the 120 foot diameter aerobrake tetrahedral truss structure. %The truss members were assumed to consist of graphite/epoxy tubes. Also, it was assumed that the nodes were constructed of 2219-T87 aluminum alloy. The magnitude of the member load assumed for design purposes was 100 kips.

Rule, William K.

1992-12-01

155

Welded Joint Analysis for Pressure Vessels with Medium and Large Diameters  

Microsoft Academic Search

Welded seal joints are recommended for applications where leak proof conditions are necessary and also when the disassembly of the closure parts is not required. Normally, for pressure vessels of medium and large diameters, the relative movements between parts of the joint is considerable due to the different movements of the individual parts or different thermal expansion coefficients. The use

E. Gómez; Equipos Nucleares

156

A portable ultrasonic phased array device for tabular joint weld inspection of offshore platform structures  

NASA Astrophysics Data System (ADS)

To meet the inspection need for complex tabular joints weld of offshore platform structures, a portable ultrasonic phased array inspection device is developed. The integrated device is small and portable. As designed, the device can implement different algorithm of the ultrasonic phased array inspection technology. With proposed inspection plan, the experiment of Y tubular joint model was performed in lab. Experiment results indicate that the possible ultrasonic phased array inspection device can detect and visualize the flaws on Y tubular joint weld, which are nearly consistent with the actual condition.

Shan, Baohua; Li, Jingan; Duan, Zhongdong; Ou, Jinping; Shen, Wei

2012-05-01

157

Investigation of Weld Joint Detection Capabilities of a Coaxial Weld Vision System.  

National Technical Information Service (NTIS)

This report describes the second phase of a series of evaluations of a vision-based welding control sensor for the Space shuttle Main Engine Robotic Welding System. The robotic welding system is presently under development at the Marshall Space Flight Cen...

K. J. Gangl J. L. Weeks

1985-01-01

158

Dual beam Nd:YAG laser welding: influence of lubricants to lap joint welding of steel sheets  

NASA Astrophysics Data System (ADS)

Laser welding is applied in large-volume production since the late eighties and has revolutionized the possibilities of designing and engineering products. Nevertheless, problems appear during application because the operational conditions in industrial environments fluctuate and can influence the welding process negatively. Contaminations, like lubricants and organic solids, are an example of changing conditions in laser beam welding. If a lap joint is welded, these materials have to be removed from the sheets, otherwise pores and surface failures may appear due to keyhole instabilities induced by uncontrolled outgassing. One possibility for solving this problem is the use of two separate laser beams. For producing these two beams several systems are available for all different kind of lasers. A bifocal optic is such a solution for an Nd:YAG laser. By using this system, the laser beam is divided after collimation with a prism. Afterwards the two beams are focussed with a lens to the surface of the sheet and two single spots are produced. If the distance between the two spots is low, one common, elliptical keyhole is created. With this system two different welding strategies are possible. The spots can be oriented parallel or normal to the feed direction. For stabilizing the laser welding of contaminated steel sheets the parallel arrangement is better, because the amount of contamination is nearly the same as in single spot welding but the total volume of the keyhole is greater and so pressure variations due to uncontrolled evaporation of contaminations are lower. In order to prove this theory and to determine the exact effects some investigations were made at the Chair of Manufacturing Technology of the University of Erlangen-Nuremberg. A 4 kW Nd:YAG laser with a beam parameter product of 25 mm*mrad and a focal distance of 200 mm was used to weld two 1 mm DC04 steel sheets together with a lap joint. Between the sheets a deep drawing lubricant, Castrol FST 6, was used to simulate the contaminations. The sheets were welded with mono- and bifocal optic, whereas with bifocal the power distribution between the two beams was varied. After welding, the seams were qualified by analyzing surface defects and mechanical properties. The results of the investigations show that the adoption of a bifocal optic can increase the stability of the welding process. The distribution between the two single spots has an essential influence on the welding result. In order to get a higher penetration and failure free seams, a 30 % to 70 % distribution between the two spots is better. Furthermore the blade angle has another slight impact on the welding result. For monofocus and bifocus a towing angle between the sheets and the beam produces better welding results. Considering these results it can be resumed that the application of a bifocal optic is a possibility to increase the quality and the stability of lap joint welding but the parameter settings for good results can only be varied in a tight tolerance zone.

Geiger, M.; Merklein, M.; Otto, A.; Blankl, A.

2007-05-01

159

Effect of Activated Flux on the Microstructure, Mechanical Properties, and Residual Stresses of Modified 9Cr-1Mo Steel Weld Joints  

NASA Astrophysics Data System (ADS)

A novel variant of tungsten inert gas (TIG) welding called activated-TIG (A-TIG) welding, which uses a thin layer of activated flux coating applied on the joint area prior to welding, is known to enhance the depth of penetration during autogenous TIG welding and overcomes the limitation associated with TIG welding of modified 9Cr-1Mo steels. Therefore, it is necessary to develop a specific activated flux for enhancing the depth of penetration during autogeneous TIG welding of modified 9Cr-1Mo steel. In the current work, activated flux composition is optimized to achieve 6 mm depth of penetration in single-pass TIG welding at minimum heat input possible. Then square butt weld joints are made for 6-mm-thick and 10-mm-thick plates using the optimized flux. The effect of flux on the microstructure, mechanical properties, and residual stresses of the A-TIG weld joint is studied by comparing it with that of the weld joints made by conventional multipass TIG welding process using matching filler wire. Welded microstructure in the A-TIG weld joint is coarser because of the higher peak temperature in A-TIG welding process compared with that of multipass TIG weld joint made by a conventional TIG welding process. Transverse strength properties of the modified 9Cr-1Mo steel weld produced by A-TIG welding exceeded the minimum specified strength values of the base materials. The average toughness values of A-TIG weld joints are lower compared with that of the base metal and multipass weld joints due to the presence of ?-ferrite and inclusions in the weld metal caused by the flux. Compressive residual stresses are observed in the fusion zone of A-TIG weld joint, whereas tensile residual stresses are observed in the multipass TIG weld joint.

Maduraimuthu, V.; Vasudevan, M.; Muthupandi, V.; Bhaduri, A. K.; Jayakumar, T.

2012-02-01

160

Evaluation of joint interface of friction stir welding between dissimilar metals using HTS-SQUID gradiometer  

NASA Astrophysics Data System (ADS)

In this study, we investigated conductive properties of joint interfaces of friction stir welding (FSW) between dissimilar metals, stainless steel SUS304 and aluminum A6063, using a SQUID nondestructive evaluation (NDE) system. With current injection method, the current maps above the FSW specimens jointed under various conditions were measured by a HTS-SQUID gradiometer. The conductivities of the joint interfaces, which were estimated from the current maps, differed between the joint conditions. By destructive tests using optical microscope, large voids were observed on the joint interfaces with low welding speed that generated excess heating. In case of one specimen, which was welded with welding speed of 500 and 200 mm/min, the conductivity of the former was higher than that of the latter, although the inside voids in the respective regions were not much different. From these results, it is suggested that the current maps were influenced not only by the conductivity of the joint interface but also by inside voids. By hardness test on the SUS boards near the interfaces, only the SUS jointed with 200 mm/min was about half softer than its matrix.

Mashiko, Y.; Hatsukade, Y.; Yasui, T.; Takenaka, H.; Todaka, Y.; Fukumoto, M.; Tanaka, S.

2010-11-01

161

46 CFR 56.30-5 - Welded joints.  

Code of Federal Regulations, 2010 CFR

...the pipe and backing off slightly before tacking. (2) Socket welds must not be used where severe erosion or crevice corrosion is expected to occur. Restrictions on the use of socket welds appear in § 56.70-15(d)(3) of this...

2009-10-01

162

46 CFR 56.30-5 - Welded joints.  

Code of Federal Regulations, 2010 CFR

...the pipe and backing off slightly before tacking. (2) Socket welds must not be used where severe erosion or crevice corrosion is expected to occur. Restrictions on the use of socket welds appear in § 56.70-15(d)(3) of this...

2010-10-01

163

Fatigue assessment of large-size welded joints based on the effective notch stress approach  

Microsoft Academic Search

In this paper the applicability of the effective notch stress approach to fatigue assessment of existing large-size specimens for cruciform joints, diaphragm joints and out-of-plane gusset joints has been investigated, by considering fatigue crack initiation points, stress distributions and fatigue strengths. By using the maximum principal stress, it is possible to distinguish whether fatigue cracks will initiate at the weld

Chitoshi Miki

2008-01-01

164

Effects of tool rotation and pin diameter on fatigue properties of friction stir welded lap joints  

Microsoft Academic Search

The objective of this study was to determine the effects of the tool pin diameter and tool rotation on the fatigue behaviour\\u000a of friction stir welded (FSW) lap joints. FSW lap joints of AA 5754 aluminium alloy plates were produced by means of a conventional\\u000a semiautomatic milling machine. Consequently, defect free FSW lap joints were produced on alloy plates at

Mustafa Kemal Kulekci; Aydin ?ik; Erdinç Kaluç

2008-01-01

165

High temperature low-cycle fatigue of friction welded joints - type 304-304 stainless steel and alloy 718-718 nickel base superalloy  

SciTech Connect

This paper assesses the high-temperature low-cycle fatigue of the Type 304 stainless steel and Alloy 718 superalloy friction-welded joints. Strain controlled low-cycle fatigue tests for 304-304 and 718-718 friction-welded specimens were carried out at 923 K in air to obtain the fatigue strength of the joints. These materials were selected as the cyclic hardening and softening materials, respectively. The 304-304 welded specimens showed inferior fatigue strength in comparison with the base metal while the 718-718 specimens exhibited fatigue strength equivalent to that of the base metal. The difference in the fatigue strength between the two materials is discussed from the viewpoint of the cyclic deformation behavior and strain reduction at weld interface.

Wakai, T. (Power Reactor and Nuclear Fuel Development Corp., Ibaraki (Japan). Oarai Engineering Center); Sakane, M.; Ohnami, M. (Ritsumeikan Univ., Kyoto (Japan). Dept. of Mechanical Engineering); Okita, K. (Hyogo Prefectural Inst. of Industrial Research, Miki (Japan). Technical Center for Machinery and Metals); Fukuchi, Y. (Hyogo Prefectural Inst. of Industrial Research, Kobe (Japan))

1993-01-01

166

Selection of welding process to fabricate butt joints of high strength aluminium alloys using analytic hierarchic process  

Microsoft Academic Search

Selection of welding process is an unstructured decision problem involving multiple attributes (factors). To provide decision support for the welding or design engineer, an all encompassing analysis of multiple attributes is necessary. The present paper reports a new procedure using an analytic hierarchic process (AHP) for the selection of a welding process to fabricate butt joints of high strength aluminium

V. Ravisankar; V. Balasubramanian; C. Muralidharan

2006-01-01

167

Impact Tensile Properties of Friction Welded Butt Joints between 6061 Aluminum Alloy and Type 304 Stainless Steel  

Microsoft Academic Search

The tensile strength and energy absorption for dissimilar metal friction welds between 6061 Al alloy and Type 304 stainless steel at high rates of loading are determined using the split Hopkinson bar. Cylindrical tensile specimens machined from as-welded butt joints of 13 mm in diameter are used in both static and impact tests. Friction welding is conducted using a brake

Takashi Yokoyama

2003-01-01

168

Effect of Activated Flux on the Microstructure and Mechanical Properties of 9Cr1Mo Steel Weld Joint  

Microsoft Academic Search

Tungsten Inert Gas (TIG) welding process is generally used to produce high quality weld joints of 9Cr – 1Mo steel. However, there is limitation associated with the depth of penetration achievable in single pass autogenous welding. Specific activated flux has been developed in the present work to enhance the depth of penetration up to 6 mm in single pass by A-

V. Arunkumar; M. Vasudevan; V. Maduraimuthu; V. Muthupandi

2011-01-01

169

Interfacial microstructure and strength of steel\\/aluminum alloy lap joint fabricated by magnetic pressure seam welding  

Microsoft Academic Search

Lap joining of low carbon steel (SPCC)\\/A6111 aluminum alloy was carried out using the magnetic pressure seam welding method. Interfacial microstructure, in particular, an intermediate layer formed at the weld interface was precisely examined using TEM. Tensile tests were also performed for the lap joints. Lap joining was successfully attained in several microseconds with no temperature increase. Weld interface of

Kwang-Jin Lee; Shinji Kumai; Takashi Arai; Tomokatsu Aizawa

2007-01-01

170

Microstructure evolution of electron beam welded Ti{sub 3}Al-Nb joint  

SciTech Connect

The microstructure evolution characterization in high containing Nb, low Al titanium aluminide alloy of electron beam welded joints was investigated by means of OM, SEM, XRD, TEM and microhardness analysis. The results indicated that the microstructure of the weld metal made with electron beam under the welding conditions employed in this work was predominantly metastable, retaining ordered {beta} phase (namely B2 phase), and was independent of the welding parameters but independent of the size and the orientation of the weld solidification structures. As the heat input is decreased, the cellular structure zone is significantly reduced, and then the crystallizing morphology of fusion zone presented dendritically columnar structure. There existed grain growth coarsening in heat affected zone (HAZ) for insufficient polygonization. Both fusion zone (FZ) and the HAZ had higher microhardness than the base metal.

Feng Jicai [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, Heilongjiang Province (China); Wu Huiqiang [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, Heilongjiang Province (China)]. E-mail: huiqiang_wu@hit.edu.cn; He Jingshan [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, Heilongjiang Province (China); Zhang Bingang [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, Heilongjiang Province (China)

2005-02-15

171

Fatigue strength of tungsten inert gas-repaired weld joints in airplane critical structures  

Microsoft Academic Search

In this work the effect of Gas Tungsten Arc Welding (GTAW) repairs on the axial fatigue strength of an AISI 4130 steel welded joint used in airframe critical to the flight-safety was investigated. Fatigue tests were performed at room temperature on 0.89mm thick hot-rolled plates with constant amplitude and load ratio of R=0.1, at 20Hz frequency. Monotonic tensile tests, optical

Marcelino P. Nascimento; Herman J. C. Voorwald; João da C. Payão Filho

2011-01-01

172

Prediction of welding buckling distortion in a thin wall aluminum T joint  

Microsoft Academic Search

In this paper, local and global welding buckling distortion of a thin wall aluminum T joint is investigated. A thermo-elastic–viscoplastic model is employed to determine longitudinal residual stresses; analysis of thermal model and elastic–viscoplastic (Anand) model are uncoupled. Molten puddle motion (speed of welding) is modeled by using time dependent birth and death element method. Three dimensional nonlinear-transient heat flow

M. Asle Zaeem; M. R. Nami; M. H. Kadivar

2007-01-01

173

Study on Corrosion Resistance of 316L Stainless Steel Welded Joint  

Microsoft Academic Search

The morphology, phase, pitting corrosion behaviors and galvanic corrosion resistance behavior of the welded joint of 316L stainless steel and Ti(TA2) clad plate were studied by scanning electron microcopy (SEM), X-ray diffraction (XRD), zero-internal resistance ammeter and potentiodynamic polarization technique. The results show that the welded 316L presents severe deformation and has intermetallic phase; moreover, more ?-ferrite phase emerges at

Han Liqing; Lin Guobiao; Wang Zidong; Zhang Hong; Li Feng; You Long

2010-01-01

174

The Effect of Strength MisMatch on Mechanical Performance of Weld Joints  

Microsoft Academic Search

This paper presents numerical studies on strength mis-match effects in welded joints. Crack growth in a mis-matched single\\u000a edge notched specimen under pure bending, with a crack lying at the center line of the weld metal, is simulated via a two-dimensional\\u000a plane strain finite element analysis (FEA). The fracture process is modeled using a cohesive zone model (CZM). The work

G. Lin; X.-G. Meng; A. Cornec; K.-H. Schwalbe

1999-01-01

175

Static and impact crack properties of a high-strength steel welded joint  

Microsoft Academic Search

In order to gain the benefits of weldable high-strength steels in pressurized equipment applications, satisfactory toughness and crack properties of the welded joint, both in the weld metal and the heat-affected –zone (HAZ), are required. Experimental investigations of toughness and crack resistance parameters through static and impact tests of a high-strength, low-alloy steel (HSLA) with a nominal yield strength of

M. Zrilic; V. Grabulov; Z. Burzic; M. Arsic; S. Sedmak

2007-01-01

176

Real-time monitoring of laser welding of galvanized high strength steel in lap joint configuration  

NASA Astrophysics Data System (ADS)

Two different cases regarding the zinc coating at the lap joint faying surface are selected for studying the influence of zinc vapor on the keyhole dynamics of the weld pool and the final welding quality. One case has the zinc coating fully removed at the faying surface; while the other case retains the zinc coating on the faying surface. It is found that removal of the zinc coating at the faying surface produces a significantly better weld quality as exemplified by a lack of spatters whereas intense spatters are present when the zinc coating is present at the faying surface. Spectroscopy is used to detect the optical spectra emitted from a laser generated plasma plume during the laser welding of galvanized high strength DP980 steel in a lap-joint configuration. A correlation between the electron temperature and defects within the weld bead is identified by using the Boltzmann plot method. The laser weld pool keyhole dynamic behavior affected by a high-pressure zinc vapor generated at the faying surface of galvanized steel lap-joint is monitored in real-time by a high speed charge-coupled device (CCD) camera assisted with a green laser as an illumination source.

Kong, Fanrong; Ma, Junjie; Carlson, Blair; Kovacevic, Radovan

2012-10-01

177

Fatigue testing welded joints for P/M Al-matrix composites  

NASA Astrophysics Data System (ADS)

To meet their need for high stiffness, many bicycles currently rely on aluminum-matrix composites. The highest strength and highest stiffness form of these material, 6092/B4C/15p, is produced by powder metallurgy techniques. The bicycles are tungsten inert-gas welded and fully heat treated after welding. A test technique has been developed to assess the static and fatigue properties of welded joints. This test technique has revealed the increased stiffness and strength of a 6092/B4C/15p-T6P composite tube joint as compared with a 6061-T6 aluminum one. This test technique is currently being used to identify fatigue properties for both tube joints.

Harrigan, William C.

1994-07-01

178

The effects of tack welding and increasing surface area on the tensile strength of silver electric and flame soldered stainless steel joints.  

PubMed

The purposes of this study were: 1) to compare silver solder joint strength using flame and electric soldering techniques, and 2) to determine the effect of tack welding and increasing metal-to-metal contact area prior to tack welding, on the tensile strength of silver solder joints. Six methods: (flame soldered; tack welded and flame soldered; increased contact area, tack welded, and flame soldered; electrosoldered; tack welded and electrosoldered; and increased contact area, tack welded, and electrosoldered) were used to produce 15 solder joints in each group. The tensile strength of the joints were tested with Instron Universal Testing Machine. Flame soldering resulted in joints with significantly higher tensile strength (P < or = 0.001). Tack welding had no significant effect on the tensile strength of the joints. Increasing the contact area had no significant effect on the tensile strength of tack welded electric soldered joints, but significantly weakened the flame soldered joints (P < or = 0.05). PMID:8784912

Gawlik, J A; Mathieu, G P; Hondrum, S

179

Type IV Cracking Susceptibility in Weld Joints of Different Grades of Cr-Mo Ferritic Steel  

NASA Astrophysics Data System (ADS)

Relative type-IV cracking susceptibility in 2.25Cr-1Mo, 9Cr-1Mo, and 9Cr-1MoVNb ferritic steel weld joint has been assessed. The type-IV cracking was manifested as preferential accumulation of creep deformation and cavitation in the relatively soft intercritical region of heat affected zone of the weld joint. The type-IV cracking susceptibility has been defined as the reduction in creep-rupture strength of weld joint compared to its base metal. The 2.25Cr-1Mo steel exhibited more susceptibility to type-IV cracking at relatively lower temperatures; whereas, at higher temperatures, 9Cr-1MoVNb steel was more susceptible. The relative susceptibility to type-IV cracking in the weld joint of the Cr-Mo steels has been rationalized on the basis of creep-strengthening mechanisms operating in the steels and their venerability to change on intercritical heating during weld thermal cycle, subsequent postweld heat treatment, and creep exposure.

Laha, K.; Chandravathi, K. S.; Parameswaran, P.; Bhanu Sankara Rao, K.

2009-02-01

180

Effect of Postweld Aging Treatment on Fatigue Behavior of Pulsed Current Welded AA7075 Aluminum Alloy Joints  

NASA Astrophysics Data System (ADS)

This article reports the effect of postweld aging treatment on fatigue behavior of pulsed current welded AA 7075 aluminum alloy joints. AA7075 aluminum alloy (Al-Zn-Mg-Cu alloy) has gathered wide acceptance in the fabrication of light weight structures requiring high strength-to weight ratio, such as transportable bridge girders, military vehicles, road tankers, and railway transport systems. The preferred welding processes of AA7075 aluminum alloy are frequently gas tungsten arc welding (GTAW) process and gas metal arc welding (GMAW) process due to their comparatively easier applicability and better economy. Weld fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification. This often results inferior weld mechanical properties and poor resistance to hot cracking. In this investigation, an attempt has been made to refine the fusion zone grains by applying pulsed current welding technique. Rolled plates of 10 mm thickness have been used as the base material for preparing multipass welded joints. Single V butt joint configuration has been prepared for joining the plates. The filler metal used for joining the plates is AA 5356 (Al-5Mg (wt.%)) grade aluminum alloy. Four different welding techniques have been used to fabricate the joints and they are: (i) continuous current GTAW (CCGTAW), (ii) pulsed current GTAW (PCGTAW), (iii) continuous current GMAW (CCGMAW), and (iv) pulsed current GMAW (PCGMAW) processes. Argon (99.99% pure) has been used as the shielding gas. Rotary bending fatigue testing machine has been used to evaluate fatigue behavior of the welded joints. Current pulsing leads to relatively finer and more equi-axed grain structure in GTA and GMA welds. Grain refinement is accompanied by an increase in fatigue life and endurance limit. Simple postweld aging treatment applied to the joints is found to be beneficial to enhance the fatigue performance of the welded joints.

Balasubramanian, V.; Ravisankar, V.; Madhusudhan Reddy, G.

2008-04-01

181

Effects of joint configuration for the arc welding of cast Ti6Al4V alloy rods in argon  

Microsoft Academic Search

Statement of problem. Titanium and its alloys are more commonly used in prosthodontics and welding has become the most common modality for their joining. Studies on the welding of titanium and its alloys have not quantified this value, though its importance has been suggested.Purpose. This study compared the strength and properties of the joint achieved at various butt joint gaps

James C. Taylor; Steven O. Hondrum; Arun Prasad; Craig A. Brodersen

1998-01-01

182

Evaluation of fatigue strength of friction stir butt-welded aluminum alloy joints inclined to applied cyclic stress  

Microsoft Academic Search

Recently, fatigue tests have been performed to investigate the fatigue behavior of friction stir butt-welded aluminum alloy joints. However, the joints of more than 10mm thick plates have rarely been tested, nor has the effect of the inclined angle of the friction stir welding line to the applied stress been studied. In this research, fatigue tests were carried out on

Shigenobu Kainuma; Hiroto Katsuki; Ichiro Iwai; Masaki Kumagai

2008-01-01

183

Fatigue strength of steel and aluminium welded joints based on generalised stress intensity factors and local strain energy values  

Microsoft Academic Search

Weld bead geometry cannot, by its nature, be precisely defined. Parameters such as bead shape and toe radius vary from joint to joint even in well-controlled manufacturing operations. In the present paper the weld toe region is modelled as a sharp, zero radius, V-shaped notch and the intensity of asymptotic stress distributions obeying Williams’ solution are quantified by means of

P. Livieri; P. Lazzarin

2005-01-01

184

Characterization of lap joints laser beam welding of thin AA 2024 sheets with Yb:YAG disk-laser  

NASA Astrophysics Data System (ADS)

Lap joints obtained by overlapping two plates are widely diffused in aerospace industry. Nevertheless, because of natural aging, adhesively bonded and riveted aircraft lap joints may be affected by cracks from rivets, voids or corrosion. Friction stir welding has been proposed as a valid alternative, although large heat affected zones are produced both in the top and the bottom plate due to the pin diameter. Interest has therefore been shown in studying laser lap welding as the laser beam has been proved to be competitive since it allows to concentrate the thermal input and increases productivity and quality. Some challenges arise as a consequence of aluminum low absorptance and high thermal conductivity; furthermore, issues are due to metallurgical challenges such as both micro and macro porosity formation and softening in the fused zone. Welding of AA 2024 thin sheets in a lap joint configuration is discussed in this paper: tests are carried out using a recently developed Trumpf TruDisk 2002 Yb:YAG disk-laser with high beam quality which allows to produce beads with low plates distortion and better penetration. The influence of the processing parameters is discussed considering the fused zone extent and the bead shape. The porosity content as well as the morphological features of the beads have been examined.

Caiazzo, Fabrizia; Alfieri, Vittorio; Cardaropoli, Francesco; Sergi, Vincenzo

2012-05-01

185

Hydrogen permeability over the joint weld of the steel parts of fusion reactor with magnet confinement of plasma  

Microsoft Academic Search

Hydrogen and its isotopes diffusion and permeability over the laser joint weld of low-activation 10Cr9WVA ferritic steels have been studied. Welding of steel sheets were produced with the help of Russian gas laser TL-5M type (l=10.6 mm, P=2.5 kW) in He atmosphere with the rate of 66 mm\\/s. Hydrogen diffusion over the joint welds was detected by the conventional method

V. V. Fedorov; E. V. Dyomina; T. M. Zasadny; L. I. Ivanov; M. D. Prusakova; N. A. Vinogradova; A. M. Zabelin

2002-01-01

186

Charpy impact test of Ti-6Al-4V joints diffusion welded at low temperature  

SciTech Connect

The Diffusion Welding (DW) of two or more sheets of Ti-6Al-4V alloy is particularly interesting for aerospace parts manufacturing. In some cases, DW can be carried out together with Superplastic Forming (SPF), because they can share a single facility and the same processing parameters, such as temperature, pressure, time, surface condition and vacuum. The overall manufacturing process is known as SPF/DW, by which it is possible to obtain honeycomb structures in a range of designs. Temperature requirements for industrial SPF of Ti-6Al-4V are very restrictive and a temperature of 1,023 K is needed. However, temperature is not so critical for DW, and the bond can be produced at lower temperatures, when other DW parameters, mainly pressure and time, are changed in a suitable way. The DW parameters for this research were chosen in order to produce DW joints below 1,023 K. The differences between DW at SPF temperatures and other lower temperatures would thus be revealed. Mechanical tests were used as a tool to check DW joints obtained at the temperatures used in the research (1,123 K and 1,023 K), and were complemented with metallographic studies. The results obtained form shear and peel tests have been already discussed. In the present work the results of impact energy tests are also presented.

Salazar, J.M.G. de; Urena, A. [Complutense Univ. of Madrid (Spain); Carrion, J.G. [National Inst. of Aeroespatial Technologies, Madrid (Spain). Materials and Structures Div.

1996-08-15

187

Modeling and analysis of novel laser weld joint designs using optical ray tracing.  

SciTech Connect

Reflection of laser energy presents challenges in material processing that can lead to process inefficiency or process instability. Understanding the fundamentals of non-imaging optics and the reflective propagation of laser energy can allow process and weld joint designs to take advantage of these reflections to enhance process efficiency or mitigate detrimental effects. Optical ray tracing may be used within a 3D computer model to evaluate novel joint and fixture designs for laser welding that take advantage of the reflective propagation of laser energy. This modeling work extends that of previous studies by the author and provides comparison with experimental studies performed on highly reflective metals. Practical examples are discussed.

Milewski, J. O. (John O.)

2002-01-01

188

NEW WELDING TECHOLOGY - THE COLD WELDING ON COGGED SURFACES  

Microsoft Academic Search

Welding by cold pressing on cogged surfaces, produces the joint of a component made from an easy deformable metal by pressing on the cogged surface of a harder metal component. Different welds between aluminium (the easy deformable component) and copper, brass, steel, stainless steel (harder component, cogged on the contact surface) can be obtained. The weld is obtained only by

Bogdan GEORGESCU; Valeriu GEORGESCU

189

A simple estimating method for reduction of welding residual stresses in thick welded joint from stress-relief annealing. Part 2: The characteristics of reduction of welding residual stresses in very thick joints during SR treatment  

SciTech Connect

Stress-relief annealing (SR treatment) is often applied to relieve welding residual stresses in the fabrication process of pressure vessels, etc. This study aims at development of an efficient method as simple as hand calculation to estimate reduction of residual stresses of very thick welded joint by SR treatment. In the first report, an estimating method was developed for relaxation tests, in uniaxial stress state, at changing and constant temperatures because the stress relaxation phenomenon is considerably similar to that observed in the SR treatment of a joint. In this report, the stresses relaxed by SR treatment in a very thick welded joint are analyzed accurately by the finite element method based on thermal elastic-plastic-creep theory. The characteristics of the changes of the welding residual stresses in multiaxial stress state are studied in detail for further development of the estimating method to SR treatment of a very thick welded joint, of which the stress state and boundary condition are very complex.

Nakacho, K.; Ueda, Y. [Osaka Univ., Ibaraki, Osaka (Japan). Joining and Welding Research Inst.

1999-02-01

190

Effects of electron beam local post-weld heat-treatment on the microstructure and properties of 30CrMnSiNi2A steel welded joints  

Microsoft Academic Search

To improve the microstructure and properties of electron beam welded joints, vacuum or furnace whole post-weld heat-treatment (FWPWHT) should usually be carried out. Electron beam local post-weld heat-treatment (EBLPWHT) is a quite new heat-treatment procedure that provides the advantages of high precision, flexibility and efficiency, energy saving, and higher productivity. In this paper, the microstructure, mechanical properties, fracture toughness and

F. R. Chen; L. X. Huo; Y. F. Zhang; L. Zhang; F. J. Liu; G. Chen

2002-01-01

191

Endurance of cruciform welded joints in 13KhGMRB high-strength steel produced by mechanized submerged-arc and gas shielded welding  

Microsoft Academic Search

Investigations were carried out into the fatigue failure resistance of welded joints in 13KhGMRB high-strength steel in relation to the methods and technological processes of welding. Bend tests were carried out on cruciform specimens welded in CO2, in a Ar + CO2 mixture, as well as under a flux with and without preheating, with a symmetric load cycle. The results

S. B. Kasatkin; L. I. Mikhodui; D. M. Kogut

1991-01-01

192

A comparative evaluation of low-cycle fatigue behavior of type 316LN base metal, 316 weld metal, and 316LN\\/316 weld joint  

Microsoft Academic Search

A comparative evaluation of the low-cycle fatigue (LCF) behavior of type 316LN base metal, 316 weld metal, and 316LN\\/316 weld\\u000a joints was carried out at 773 and 873 K. Total strain-controlled LCF tests were conducted at a constant strain rate of 3 ×\\u000a 10?3 s?1 with strain amplitudes in the range ±0.20 to ±1.0 pct. Weld pads with single V

M. Valsan; D. Sundararaman; K. Bhanu Sankara Rao; S. L. Mannan

1995-01-01

193

Effects of defect size in root region on fatigue strength of fillet welded joints—root failure of non?load?carrying cruciform fillet welded joints due to toe treatment (2 report)  

Microsoft Academic Search

This paper describes an investigation of the effects of the defect size in the root region on the fatigue strength of non?load?carrying cruciform fillet welded joints by FEM analysis, fatigue tests, and hardness tests. The results may be summarised as follows. 1. Through TIG dressing of the toe region of fillet welded joints, joints have a fatigue limit of 1.4?2.5

S. Ohta; H. Kitamura

1994-01-01

194

Fatigue behaviour of Al2024-T3 friction stir welded lap joints  

Microsoft Academic Search

The aim of this work is the characterization of the fatigue behaviour of AA2024-T3 friction stir welded overlap joints produced at German Aerospace Center (DLR) of Cologne (D). In these joints, two crack-like unwelded zones are present at overlap ends. The stress intensity factor at the crack tip and the fatigue crack path have been studied using the FE code

D. Fersini; A. Pirondi

2007-01-01

195

Fatigue Life Improvement for Cruciform Welded Joint by Mechanical Surface Treatment using Hammer Peening and UNSM  

NASA Astrophysics Data System (ADS)

For the improvement of fatigue strength of welded structures, mechanical post treatments have been applied in various industrial fields and have in most cases been founded to give substantial increases in their fatigue lives. These methods, generally, consist of the modification of weld toe geometry and the introduction of compressive residual stresses. In mechanical surface treatments, e.g. PHP (pneumatic hammer peening) and UNSM (ultrasonic nano-crystal surface modification), the weld profile is modified due to remove or reduce minute crack-like flaws, and compressive residual stresses are also induced. In this study, a pneumatic hammer peening procedure and a UNSM device were introduced, and a quantitative measure of fatigue strength improvement was performed. The fatigue strength at 2 × 106 cycles of hammer-peened and UNSM treated on a non-load carrying cruciform welded joint shows 220 and 260MPa, respectively, which are more than two times higher than that of as-welded specimen. Especially, the surface layer in the vicinity weld toe treated by the UNSM provides nano-crystal structure created by an ultrasonic cold forging and introduces very high welding residual stress in compression.

Han, Seung-Ho; Han, Jeong-Woo; Nam, Yong-Yun; Cho, In-Ho

196

Stress concentration factor analysis for welded, notched tubular T-joints under combined axial, bending and dynamic loading  

Microsoft Academic Search

The finite element analysis will be used in this study to predict the location of hot-spot stresses in a welded tubular T-joint. The fillet weld has been modeled all around the joint. Using symmetry, the tubular T-joint is submitted to axial, in-plane bending (IPB) and out-of-plane bending (OPB) loadings. The finite element method analysis shows that stresses are very high

A. N’Diaye; S. Hariri; G. Pluvinage; Z. Azari

2009-01-01

197

A fracture mechanics based fatigue life prediction for welded joints of square tubes  

Microsoft Academic Search

Square tubes of mild and low alloy steels are extensively used in vehicle structures and offshore platforms. Despite this fact the fatigue behaviour of welded nodes of these tubes is not sufficiently known, especially in thin sections.The paper presents the results of fatigue life predictions based on fracture mechanics, in non-load carrying T and also load carrying cruciform joints. The

J. M. Ferreira; A. H. Pereira; C. M. Branco

1995-01-01

198

A boundary element analysis of misaligned load-carrying cruciform welded joints  

Microsoft Academic Search

Although it has been found that misalignment of the welded joints can reduce fatigue strength significantly, further studies are still required for comprehensive investigation, including varying geometry variables. In this study, boundary element technique and hypersingular boundary integral equation (HBIE) are employed to calculated the notch stress concentration factors and then predict the fatigue life as this method can lead

S. T Lie; S Lan

1998-01-01

199

Assessment of some factors affecting fatigue endurance of welded cruciform joints using statistical techniques  

Microsoft Academic Search

Three statistical techniques have been used to optimise some of the factors affecting fatigue life of Flux Cored Arc Welded (FCAW) cruciform joints containing Lack of Penetration (LOP) defects. High strength, quenched and tempered steel (ASTM 517 ‘F’ Grade) has been used as the base material throughout the investigation. Design of Experiments (DoE) concept has been used to optimise the

V. Balasubramanian; B. Guha

1999-01-01

200

Experimental study on the fatigue behaviour of welded tubular K-joints for bridges  

Microsoft Academic Search

Fatigue tests were carried out on welded circular hollow section K-joints typical to bridges. The tests specimens were large-scale (approximately 9 m long and 2 m high) trusses loaded in the plane of the truss. Measured member stresses showed that a significant proportion of the load in a truss member may be due to bending, underlining the importance of considering

Ann Schumacher; Alain Nussbaumer

2006-01-01

201

The effect of seismic loading on the fatigue strength of welded joints  

Microsoft Academic Search

Earthquakes sometimes damage steel structures. Structures which are not seriously damaged are still used after earthquakes but their fatigue strength may have been reduced by the large cyclic loadings imposed by the earthquakes. In order to clarify the effect of seismic loading on the fatigue strength of welded joints, high cycle fatigue and variable amplitude fatigue tests after a number

Y. Kondo; K. Okuya

2007-01-01

202

EXECUTIVE SUMMARY Type IV Cracking in Modified 9Cr1Mo Steel Weld Joint  

Microsoft Academic Search

The steam generator of the Prototype Fast Breeder (PFBR) is being fabricated out of modified 9Cr-1Mo steel. Type IV cracking in the heat affected zone (HAZ) of weld joint limits the life of the component. Detailed investigations have been carried out to understand the cracking so as to mitigate or minimize the problem. Creep tests performed on the steel and

203

Modelling of crack coalescence in 2024-T351 Al alloy friction stir welded joints  

Microsoft Academic Search

In the present work, FSW of 2024-T351 Al alloy is characterised in terms of weld residual stress and cyclic properties. A fatigue endurance of the FSW joint was also investigated and discussed. Critical areas for natural fatigue crack initiation in FSW are pinpointed. The fatigue mechanism in FSW is identified to follow a multiple crack coalescence nature. The numbers of

Aidy Ali; M. W. Brown; C. A. Rodopoulos

2008-01-01

204

Determination of optimum heating zones in strengthening of longitudinal welded joints in cylindrical shells  

Microsoft Academic Search

In the solution of the problem it is assumed that the residual stresses acting in the direction of the axis of the longitudinal welded joint in the cylindrical shell are of the tensile type and are the dominant type of stress. To reduce the magnitude of these stresses~ the heating regions are distributed in such a manner as to ensure

V. N. Maksimovich; E. N. Novosad; G. V. Plyatsko

1982-01-01

205

Stress indices for girth welded joints, including radial weld shrinkage, mismatch and tapered-wall transitions  

Microsoft Academic Search

A review is presented of B, C and K stress indices used in the ASME Nuclear Power Plant Code for girth butt welds and girth fillet welds. Theoretical stresses are presented to aid in evaluating C-indices. Fatigue test data are presented to aid in evaluating K-indices and CK-products. A limit load theory is presented to aid in evaluating B-indices. As

E. C. Rodabaugh; S. E. Moore

1978-01-01

206

Microstructure and Properties of TIG/FSW Welded Joints of a New Al-Zn-Mg-Sc-Zr Alloy  

NASA Astrophysics Data System (ADS)

A new Al-Zn-Mg-Sc-Zr alloy with low Sc content was welded by tungsten inert gas (TIG) and friction stir welding (FSW) techniques. The microstructure and properties of those two welded joints were investigated by property tests and microstructural observations. The results show that the new Al-Zn-Mg-Sc-Zr alloy has desirable welding property. The ultimate tensile strength and welding coefficient of the TIG joint reach 405 MPa and 76.7%, respectively, and in FSW joint those property values reach 490 MPa and 92.6%, respectively. The studied base metal has a deformed fibrous subgrains structure, many nano-scaled Al3(Sc,Zr) particles, and very fine aging precipitates. In the TIG joint, the fusion zone consists of coarsened dendritic grains and the heat-affected zone (HAZ) has fibrous micro-scaled subgrains. The FSW welded joint is characterized by a weld nugget zone, thermo-mechanically affected zone (TMAZ), and HAZ. Due to plastic deformation around the rotating pin and anti-recrystallized effectiveness of Al3(Sc,Zr) particles, the weld nugget zone has a very fine subgrain structure. The TMAZ experiences some dissolution of aging precipitates. Coarsening of aging precipitates was observed in the HAZ. The better mechanical properties of the FSW joint are derived from a fine subgrain structure and homogeneous chemical compositions.

Lei, Xuefeng; Deng, Ying; Peng, Yongyi; Yin, Zhimin; Xu, Guofu

2013-09-01

207

Modeling and design of energy concentrating laser weld joints  

Microsoft Academic Search

The application of lasers for welding and joining has increased steadily over the past decade with the advent of high powered industrial laser systems. Attributes such as high energy density and precise focusing allow high speed processing of precision assemblies. Other characteristics of the process such as poor coupling of energy due to highly reflective materials and instabilities associated with

J. O. Milewski; E. Sklar

1997-01-01

208

T-joints of Ti alloys with hybrid laser-MIG welding: macro-graphic and micro-hardness analyses  

NASA Astrophysics Data System (ADS)

Titanium alloys are characterized by high mechanical properties and elevated corrosion resistance. The combination of laser welding with MIG/GMAW has proven to improve beneficial effects of both processes (keyhole, gap-bridging ability) while limiting their drawbacks (high thermal gradient, low mechanical resistance) In this paper, the hybrid Laser-GMAW welding of Ti-6Al-4V 3-mm thick sheets is investigated using a specific designed trailing shield. The joint geometry was the double fillet welded T-joint. Bead morphologies, microstructures and mechanical properties (micro-hardness) of welds were evaluated and compared to those achieved for the base metals.

Spina, R.; Sorgente, D.; Palumbo, G.; Scintilla, L. D.; Brandizzi, M.; Satriano, A. A.; Tricarico, L.

2012-02-01

209

CHEMICAL AND STRUCTURAL CHANGES FOR BIMETALLIC MATERIALS OBTAINED BY THE WELDING PROCESS  

Microsoft Academic Search

This paper presents the transformations which take place during the obtaining process of bimetallic materials. As a plating process was used the welding. The added material was a bronze with aluminum complex alloyed with iron, nickel. The based material was the steel. EDAX analyses and microstructures analyses were done in order to explain the metallurgical processes which take place during

Felicia Bratu

210

Microstructure and corrosion behavior of shielded metal arc-welded dissimilar joints comprising duplex stainless steel and low alloy steel  

NASA Astrophysics Data System (ADS)

This work describes the results of an investigation on a dissimilar weld joint comprising a boiler-grade low alloy steel and duplex stainless steel (DSS). Welds produced by shielded metal arc-welding with two different electrodes (an austenitic and a duplex grade) were examined for their microstructural features and properties. The welds were found to have overmatching mechanical properties. Although the general corrosion resistance of the weld metals was good, their pitting resistance was found to be inferior when compared with the DSS base material.

Srinivasan, P. Bala; Muthupandi, V.; Sivan, V.; Srinivasan, P. Bala; Dietzel, W.

2006-12-01

211

Robotic gas metal arc welding of small diameter saddle type joints using multi-stripe structured light  

NASA Astrophysics Data System (ADS)

Single-stripe structured light sensors are widely used in conjunction with arc welding robots for seam-tracking purposes. The interaction of the projected light with the weld joint and component surfaces produces characteristic line shapes with feature points that can be recognized at high speed by an underlying vision system. Unfortunately they are suitable only for the major classes of weld joint typically encountered within industry--long, straight, or gently curving fillet or butt joints. We present a multistripe structured light sensor that detects and measures the position of the saddle type weld joint formed by two small (< 50-mm)-diameter intersecting tubes. The underlying image processing algorithms detect the weld feature points from each stripe along with four calibration points to generate the entire weld path in the robot workcell base coordinate system before welding commences. The system is validated within an existing welding application; detecting 93% of the weld feature points within +/- 0.4 mm when used on 30-mm-diam tubes.

Bonser, Gary R.; Parker, Graham A.

1999-11-01

212

Synchrotron X-ray CT characterization of friction-welded joints in tial turbocharger components  

NASA Astrophysics Data System (ADS)

Titanium aluminide (TiAl) is an advanced intermetallic material and is being investigated for application in turbocharger components for diesel engines. A TiAl turbocharger rotor consists of a cast TiAl turbine wheel and a Ti-alloy shaft that are joined by friction welding. Although friction welding is an established industrial process, it is still challenging to join dissimilar materials especially for brittle intermetallics. These joints are therefore required to be inspected using a nondestructive evaluation (NDE) method. In this study, synchrotron X-ray computed tomography (CT) developed at the Advanced Photon Source at Argonne National Laboratory was used for NDE characterization of friction-welded joint in three TiAl turbocharger rotors. The filtered synchrotron X-ray source has high peak energies to penetrate thick metallic materials, and the detector (imager) has high spatial resolutions to resolve small flaws. The CT inspections revealed detailed 3D crack distributions within poorly welded joints. The crack detection sensitivity and resolution was calibrated and found to be correlated well with destructive examination.

Sun, J. G.; Kropf, A. J.; Vissers, D. R.; Sun, W. M.; Katsoudas, J.; Yang, N.; Fei, D.

2012-05-01

213

Effect of Vibrations with Different Frequencies on Reduction of Residual Stress of Welded Joint  

NASA Astrophysics Data System (ADS)

Welding is widely used for construction of many structures. It is well known that residual stress is generated near the bead because base metal is heated near the bead. Tensile residual stress on the surface degrades fatigue strength. Some reduction methods of residual stress are practically used, for example, heat treatment and shot peening. The authors developed a new method for reduction of residual stress using vibration during welding. In this method, single vibration was used. The effectiveness of the method was demonstrated. In this paper, the effect of vibrations with different frequencies on reduction of residual stress is examined. The effect is examined experimentally by butt-welding of thin plates. First, two thin plates are butt-welded using ultrasonic vibrations with different frequencies on each plate. Some plates are welded using single ultrasonic vibration and without ultrasonic vibration for comparison. When thin plates are welded using vibrations with different frequencies, tensile residual stresses are reduced and reduction rate is largest compared with other conditions. Second, two thin plates are butt-welded using ultrasonic vibration and vibration with low frequency. Some plates are welded using single vibration and without vibration for comparison. In this case, tensile residual stresses are reduced and reduction rate is largest compared with other conditions. Obtained results are examined by analytical method.

Aoki, Shugeru; Nishimura, Tadashi; Hiroi, Tetsumaro; Hirai, Seiji

214

Mechanical properties and fatigue strength of high-manganese non-magnetic steel\\/carbon steel welded joints  

Microsoft Academic Search

This paper describes performance tests of dissimilar material welded joints produced from carbon steel and a new type of high-manganese non-magnetic steel with improved machinability. The basic mechanical properties of these joints are first described. Fatigue tests are then conducted for purposes of fatigue strength design of the joints within the context of an evaluation of their suitability for application

E. Nakaji; S. Ikeda; Y. C. Kim; Y. Nakatsuji; K. Horikawa

1998-01-01

215

Assessment of stress intensity factors for load-carrying fillet welded cruciform joints using a digital camera  

Microsoft Academic Search

This paper presents an experimental method to determine the stress intensity factors (SIFs) of load-carrying fillet welded cruciform joints. This experimental method measured the crack opening displacements (CODs) of the cruciform joint detail by a common digital camera, and utilized the acquired COD data to derive the SIF for the joint detail by a suggested least-squares procedure. A total of

H. Y. Chung; S. H. Liu; R. S. Lin; S. H. Ju

2008-01-01

216

Effect of Zinc Coatings on Joint Properties and Interfacial Reactions in Aluminum to Steel Ultrasonic Spot Welding  

NASA Astrophysics Data System (ADS)

Dissimilar joining of aluminum to steel sheet in multimaterial automotive structures is an important potential application of ultrasonic spot welding (USW). Here, the weldability of different zinc-coated steels with aluminum is discussed, using a 2.5-kW USW welder. Results show that soft hot-dipped zinc (DX56-Z)-coated steel results in better weld performance than hard (galv-annealed) zinc coatings (DX53-ZF). For Al to hard galv-annealed-coated steel welds, lap shear strengths reached a maximum of ~80% of the strength of an Al-Al joint after a 1.0 s welding time. In comparison, welds between Al6111-T4 and hot dipped soft zinc-coated steel took longer to achieve the same maximum strength, but nearly matched the Al-Al joint properties. The reasons for these different behaviors are discussed in terms of the interfacial reactions between the weld members.

Haddadi, F.; Strong, D.; Prangnell, P. B.

2012-03-01

217

Effects of weld profile and undercut on fatigue crack propagation life of thin-walled cruciform joint  

Microsoft Academic Search

Fatigue may occur in undercarriages and support systems of trailers, haymakers, graders and swing-ploughs made up of thin-walled tubular sections with wall thicknesses less than 4 mm. Little research has been done on the fatigue of thin-walled tubular sections below 4 mm thickness. The weld profile and weld undercut may affect the fatigue crack propagation life of welded joints especially

F. R. Mashiri; X. L. Zhao; P. Grundy

2001-01-01

218

Microstructure characteristics and mechanical property of aluminum alloy\\/stainless steel lap joints fabricated by MIG welding–brazing process  

Microsoft Academic Search

Lap joints of aluminum alloy 2B50 and stainless steel 1Cr18Ni9Ti were welded by MIG welding–brazing method with 4043 Al–Si filler metal. The effect of aluminizing coating and galvanized zinc coating on fusion metal spreadability were studied. The aluminized coating had limited effect to promote weld surface appearance and obvious micro-cracks were found between the compound layer and the steel side.

Hongtao Zhang; Jiakun Liu

2011-01-01

219

Stress and strain concentration factors of welded multiplanar joints between square hollow sections  

NASA Astrophysics Data System (ADS)

The results of an experimental and numerical investigation on the fatigue behavior of uniplanar and multiplanar joints made of square hollow sections are presented in this work. This work has been carried out within the framework of the research program DCT80-1457 sponsored by the Netherlands Technical Foundation (STW). After calibration of the numerical models of the joints with the experimental results, a numerical investigation for the joint parameters for the determination of stress concentration factors (SCF's) and strain concentration factors (SNCF's) was conducted. The software 'HOTSHS' is developed which uses the data base of this parameter study to calculate the hot spot stresses at the weld toes in the various joint types investigated for a given load combination, within the range of the parameters studied. The aim of this research program is to provide stress concentration factors for the fatigue design of uniplanar and multiplanar joints in square hollow sections.

Panjehshahi, E.

220

Welding.  

ERIC Educational Resources Information Center

|This curriculum guide is designed for use by South Carolina vocational education teachers as a continuing set of lesson plans for a two-year course on welding. Covered in the individual sections of the guide are the following topics: an orientation to welding, oxyacetylene welding, advanced oxyacetylene welding, shielded metal arc welding, TIG…

South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

221

Two-dimensional and three-dimensional magnification factors, M k, for non-load-carrying fillet welds cruciform joints  

Microsoft Academic Search

Two-dimensional Mk factors at the weld toe of non-load-carrying transverse welded attachments are derived indirectly using the principle of superposition and stresses obtained from boundary element analysis. The results are in good agreement with that obtained by Maddox and Andrews [1] for different ratios of l\\/T, where l is the weld toe to weld toe distance, and T is the

S. T. Lie; Z. Zhao; S. H. Yan

2000-01-01

222

Development of Laser Beam Delivery and Welding Head for the Inner and Outer Diameter Joints of the AGT 1500 Recuperator.  

National Technical Information Service (NTIS)

The purpose of this TACOM project was to develop and demonstrate a production suitable laser welding head, which could successfully join the plate edges of the inner and outer joints of the AFT 1500 recuperator. This project investigated the laser welding...

M. B. Vollaro

1986-01-01

223

Effect of welding processes and consumables on high cycle fatigue life of high strength, quenched and tempered steel joints  

Microsoft Academic Search

Austenitic stainless steel (ASS) welding consumables are traditionally used for welding quenched and tempered steels as they have higher solubility for hydrogen in austenitic phase. An attempt was made in this investigation to explore an alternate consumable to replace expensive ASS consumables. Austenitic stainless steel and low hydrogen ferritic steel were used to fabricate the joints by shielded metal arc

G. Magudeeswaran; V. Balasubramanian; G. Madhusudhan Reddy

2008-01-01

224

Fatigue strength evaluation of load-carrying cruciform fillet-welded joints made with mild steel plates of different thickness  

Microsoft Academic Search

This study examined the fatigue behavior of load-carrying cruciform fillet-welded joints made with mild steel plates of different thickness. Fatigue tests were carried out on four types of welded joint, made from two 6-, 9-, 14-, or 25-mm thick main plates and one 6- or 14-mm thick cross plate. The fatigue strength was also analyzed using linear elastic fracture mechanics

Shigenobu Kainuma; In-Tae Kim

2005-01-01

225

‘Tailored blanks’ for automotive components. Evaluation of mechanical and metallurgical properties and corrosion resistance of laser-welded joints  

Microsoft Academic Search

The main aim of this research is to investigate the suitability of ‘tailored blanks’, fabricated with laser welding technology, prior to forming. It is also a review of their fatigue and corrosion behaviour.During the experiments, laser-welded joints were performed using different steel\\/thickness combinations, most commonly used in today's automobile industry. Joints were assessed by metallographic examination, as well as by

R. Aristotile; M. Fersini

1999-01-01

226

Influence of preheating on API 5LX80 pipeline joint welding with self-shielded flux-cored wire  

Microsoft Academic Search

The present work refers to the characterization of the mechanical properties of API 5L-X80 pipeline joints welded with self-shielded flux-cored wire. This process was evaluated under preheating conditions, with a uniform and steady heat input. All joints were welded in a flat position (IG), with the pipe turning and the torch still. Tube dimensions were 762 mm in external diameter

R. Cooper; J. H. F. Silva; R. E. Trevisan

2005-01-01

227

Evaluation of creep damage in heat affected zone of thick welded joint for Mod.9Cr–1Mo steel  

Microsoft Academic Search

Mod.9Cr–1Mo steel has been used for boiler components in ultra-supercritical (USC) thermal power plants. The creep strength of welded joint of this steel decreases due to the formation of Type IV cracking in heat affected zone (HAZ) at higher temperatures. The present paper aims to clarify the damage processes and mechanisms of the welded joint for Mod.9Cr–1Mo steel. Long-term creep

Yongkui Li; Hiromichi Hongo; Masaaki Tabuchi; Yukio Takahashi; Yoshio Monma

2009-01-01

228

Effect of abnormal grain growth on tensile strength of Al–Cu–Mg alloy friction stir welded joints  

Microsoft Academic Search

An Al-4.5%Cu-1.5%Mg aluminum alloy with a T4 temper was friction stir welded, and the effect of the abnormal grain growth\\u000a on the tensile strength of joints was investigated. Abnormal grain growth usually happens during post weld heat treatment.\\u000a It is found that the tensile strength and elongation of the heat-treated joint will increase significantly if this phenomenon\\u000a completely happens in

M. A. Safarkhanian; M. Goodarzi; S. M. A. Boutorabi

2009-01-01

229

Numerical Simulation on Weld Joint Offset for Tailor-Welded Blank in MultiPoint Forming  

Microsoft Academic Search

Multi-point forming (MPF) is a novel manufacturing technique for three-dimensional sheet metal. It employs two reconfigurable element groups to approximate the continuous upper and lower solid dies. With the technique, rapid fabrication of 3D sheet metal part is realized. In this paper, to investigate the feasibility of the multi-point forming for the tailor-welded blank (TWB), the explicit finite element model

Wei Liu; Mingzhe Li

2009-01-01

230

High Temperature Plasticity of Bimetallic Magnesium and Aluminum Friction Stir Welded Joints  

NASA Astrophysics Data System (ADS)

The high temperature deformation of a bimetallic AZ31/AA6061 Friction Stir Welded joint was investigated in the present study by constant load creep experiments carried out at 473 K (200 °C). The microstructural analysis revealed the strongly inhomogeneous nature of the weld, which was characterized by an extremely fine grain size in the magnesium-rich zones and by the extensive presence of intermetallic phases. In the high stress regime, the creep strain was concentrated in the refined and particle-rich microstructure of the weld zone, while the AA6061 base metal remained undeformed. In the low stress regime, deformation became more homogeneously distributed between the AZ31 base metal and the weld zone. The creep behavior of the weld was found to obey the constitutive equation describing the minimum creep rate dependence on applied stress for the base AZ31, slightly modified to take into account the finer microstructure and the role of secondary phase particles, i.e., the retardation of grain growth and the obstruction of grain boundary sliding.

Regev, Michael; El Mehtedi, Mohamad; Cabibbo, Marcello; Quercetti, Giovanni; Ciccarelli, Daniele; Spigarelli, Stefano

2013-10-01

231

Effect of residual stresses on fatigue crack initiation life for butt-welded joints  

Microsoft Academic Search

This investigation performs a thermal elasto-plastic analysis using finite element techniques to analyse thermomechanical behaviour and evaluate residual stresses in weldments, and develops an effective procedure by combining the finite element, strain-life methods and considerations of the residual stress effect to predict fatigue crack initiation (FCI) life in weldments. Herein, the FCI lives of butt-welded joints are forecast using the

Tso-Liang Teng; Peng-Hsiang Chang

2004-01-01

232

Effect of fatigue damage on the dynamic response frequency of spot-welded joints  

Microsoft Academic Search

The effect of fatigue damage on the dynamic natural frequency response was studied over the entire fatigue life process for tensile-shear spot-welded joints. The results of the experimental study showed that the changes to the specimens’ natural frequency varied non-linearly with the cycle ratio or damage fraction, and that relatively large changes in the natural frequency could be measured near

De-Guang Shang; Mark E. Barkey; Yi Wang; Teik C. Lim

2003-01-01

233

Effect of weld metal microstructure on the monotonic and cyclic mechanical behavior of tig welded 2091 Al–Li alloy joints  

Microsoft Academic Search

The effect of TIG welding on the mechanical behavior of Al–Li alloy 2091-T851 has been investigated by means of tensile and fatigue testing. Compared to the base alloy, as-welded joints were found to display significant reductions in both tensile and fatigue strengths and to suffer a drastic degradation in ductility. Such behavior is primarily related to the presence of large

I. G Solórzano; F. A Darwish; M. C de Macedo; S. O de Menezes

2003-01-01

234

Fatigue crack growth in 2024-T351 friction stir welded joints: Longitudinal residual stress and microstructural effects  

Microsoft Academic Search

The role of longitudinal residual stress on propagation of fatigue cracks was examined in friction stir welds produced in 2024-T351 aluminum alloy. Fatigue crack growth rate was obtained through constant ?KIapp tests for notches at different distances from the weld centerline. Subsequently, crack growth was correlated to weld residual stress measured by the cut-compliance method. It was found that residual

L. Fratini; S. Pasta; A. P. Reynolds

2009-01-01

235

Investigation of the mechanical properties of friction-welded joints between AISI 304L and AISI 4340 steel as a function rotational speed  

Microsoft Academic Search

In this study, standard AISI 304L austenitic stainless steel and AISI 4340 steel couple were welded by friction welding process using five different rotational speeds. The joining performances of AISI 304L\\/AISI 4340 friction-welded joints were studied and the influences of rotational speed on the microstructure and mechanical properties of the welded joints were also estimated. The microstructural properties of heat

N. Özdemir

2005-01-01

236

Ultrasonic examination and inservice inspection of LMFBR transition joint welds  

Microsoft Academic Search

Ultrasonic examination and inservice inspection of transition joints between 2 1\\/4Cr-1Mo and Type 316 stainless steel is described for liquid metal fast breeder reactor applications. The detection of creep fatigue cracks as small as 0.5% of the pipe wall thickness in the 2 1\\/4Cr-1Mo heat affected zone was demonstrated. The detection of 3% artificial defects in the heat affected zone

Day

1983-01-01

237

Effect of Activated Flux on the Microstructure, Mechanical Properties, and Residual Stresses of Modified 9Cr1Mo Steel Weld Joints  

Microsoft Academic Search

A novel variant of tungsten inert gas (TIG) welding called activated-TIG (A-TIG) welding, which uses a thin layer of activated flux coating applied on the joint area prior to welding, is known to enhance the depth of penetration during autogenous TIG welding and overcomes the limitation associated with TIG welding of modified 9Cr-1Mo steels. Therefore, it is necessary to develop

V. Maduraimuthu; M. Vasudevan; V. Muthupandi; A. K. Bhaduri; T. Jayakumar

2011-01-01

238

Electrical, Corrosion, and Mechanical Properties of Aluminum-Copper Joints Produced by Explosive Welding  

NASA Astrophysics Data System (ADS)

This study investigates the microstructure, electrical, corrosion, and mechanical properties of plate-shaped aluminum-copper couple produced using the explosive welding method. Mechanical tests, including hardness, tensile, tensile-shear, and impact test, concluded that the Al-Cu bimetal had an acceptable joint resistance. In this study, local intermetallic regions formed on the interface of the joint of the aluminum-copper bimetal, produced using the explosive welding technique. However, the formed intermetallic regions had no significant effect on the mechanical properties of the joint, except for increasing its hardness. According to electrical conductivity tests, the Al-Cu bimetal had an average electrical conductivity in comparison to the electrical conductivity of aluminum and copper, which were the original materials forming the joint. According to the results of electro-chemical corrosion test, during which galvanic corrosion formed, the Al side of the Al-Cu bimetal was more anodic due to its high electronegativity; as a result, it was exposed to more corrosion in comparison to the copper side.

Acarer, Mustafa

2012-11-01

239

A robust method for vision-based seam tracking in robotic arc welding  

Microsoft Academic Search

This paper presents a robotic seam tracking system which is aimed at achieving robustness against some welding noises such as arc glares, welding spatters, fumes etc. In particularly, a syntactic analysis is used to improve the extraction reliability of the joint features. The joint features thus obtained are used to extract the 3-dimensional information of the weld joint and then

Jae Seon Kim; Young Tak Son; Hyung Suck Cho; Kwang Il Koh

1995-01-01

240

Effect of weld size on fatigue crack growth behaviour of cruciform joints by strain energy density factor approach  

Microsoft Academic Search

The effect of weld size on fatigue crack growth behaviour of cruciform joints containing lack of penetration defect has been analysed by using the strain energy density factor concept. Load carrying cruciform joints were fabricated from ASTM 517`F' grade steel. Fatigue crack growth experiments were carried out in a mechanical resonance vertical pulsator (SCHENCK 200 kN capacity) with a frequency

V. Balasubramanian; B. Guha

1999-01-01

241

The Peak Stress Method applied to fatigue assessments of steel tubular welded joints subject to mode-I loading  

Microsoft Academic Search

The paper presents the practical aspects involved in structural design of tubular joints mainly employed in roller coasters manufacturing. Different design standards, commonly adopted in fatigue assessments, are considered and compared. Then some constant amplitude fatigue test results concerning typical tubular welded joints are presented. Finally the experimental results and additional test data taken from the literature are compared with

Giovanni Meneghetti; Bruno Atzori; Giampiero Manara

2010-01-01

242

A comparative evaluation of low-cycle fatigue behavior of type 316LN base metal, 316 weld metal, and 316LN/316 weld joint  

SciTech Connect

A comparative evaluation of the low-cycle fatigue (LCF) behavior of type 316LN base metal, carried out at 773 and 873 K. Total strain-controlled LCF tests were conducted at a constant strain rate of 3 {times} 10{sup {minus}3} s{sup {minus}1} with strain amplitudes in the range {+-}0.20 to {+-}1.0 pct. Weld pads with single V and double V configuration were prepared by the shielded metal-arc welding (SMAW) process using 316 electrodes for weld-metal and weld-joint specimens. Optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) of the untested and tested samples were carried out to elucidate the deformation and the fracture behavior. The cyclic stress response of the base metal shows a very rapid hardening to a maximum stress followed by a saturated stress response. Weld metal undergoes a relatively short initial hardening followed by a gradual softening regime. Weld joints exhibit an initial hardening and a subsequent softening regime at all strain amplitudes, except at low strain amplitudes where a saturation regime is noticed. The initial hardening observed in base metal has been attributed to interaction between dislocations and solute atoms/complexes and cyclic saturation to saturation in the number density of slip bands. The 18-8 group of austenitic stainless steels, such as AISI type 316, 304, and their modified grades, finds applications as structural material for various components of the liquid-metal-cooled fast breeder reactor (LMFBR).

Valsan, M.; Sundararaman, D.; Sankara Rao, K.B.; Mannan, S.L. [Indira Gandhi Centre for Atomic Research, Tamil Nadu (India)

1995-05-01

243

Impact of tool wear on joint strength in friction stir spot welding of DP 980 steel  

SciTech Connect

Friction stir spot welding has been shown to be a viable method of joining ultra high strength steel (UHSS), both in terms of joint strength and process cycle time. However, the cost of tooling must be reasonable in order for this method to be adopted as an industrial process. Recently a new tool alloy has been developed, using a blend of PCBN and tungsten rhenium (W-Re) in order to improve the toughness of the tool. Wear testing results are presented for two of these alloys: one with a composition of 60% PCBN and 40% W-Re, and one with 70% PCBN and 30% W-Re. The sheet material used for all wear testing was 1.4 mm DP 980. Lap shear testing was used to show the relationship between tool wear and joint strength. The Q70 tool provided the best combination of wear resistance and joint strength.

Miles, Michael; Ridges, Chris; Hovanski, Yuri; Peterson, Jeremy; Santella, M. L.; Steel, Russel

2011-09-14

244

Tensile properties of friction stir welded and friction stir welded-superplastically formed Ti–6Al–4V butt joints  

Microsoft Academic Search

A University and Industry collaborative research project was undertaken to evaluate the performance of as friction stir welded (FSW) and friction stir welded-superplastically formed Ti–6Al–4V alloy sheets. The purpose of this particular effort was to evaluate the tensile properties of friction stir welded and superplastically formed friction stir welded Ti–6Al–4V. Welds were produced out of both standard grain and fine

M. Ramulu; P. D. Edwards; D. G. Sanders; A. P. Reynolds; T. Trapp

2010-01-01

245

Study of the fatigue behavior in welded joints of stainless steels treated by weld toe grinding and subjected to salt water corrosion  

Microsoft Academic Search

This paper presents the fatigue results obtained in two types of stainless steels: Duplex S31803 and Austenitic 304L. The main objective was to compare the fatigue behavior in terms of environment (air and 3% NaCl) and weld toe treatment (as welded and toe grinding). The tests were carried out in tension on cruciform specimens with a constant amplitude fatigue cycle

R. Baptista; V. Infante; C. M. Branco

2008-01-01

246

EFFECT OF TOOL FEATURE ON THE JOINT STRENGTH OF DISSIMILAR FRICTION STIR LAP WELDS  

SciTech Connect

Several variations of friction stir tools were used to investigate the effects on the joint strengths of dissimilar friction stir lap welds. In the present lap weld configuration the top sheet was a 2.32 mm thick Mg (AZ 31) alloy. The bottom sheet consisted of two different steels, a (i) 0.8 mm thick electro-galvanized (EG) mild steel, or a (ii) 1.5 mm thick hot dip galvanized (HDG) high strength low alloy (HSLA) steel. Initially the tool shape was modified to accommodate the material, at which point the tool geometry was fixed. With a fixed tool geometry an additional feature was added to the pin bottom on one of the tools by incorporating a short hard insert, which would act as a stronger bottom sheet cutter. The effects of such modification on the unguided lap shear strength, and associated microstructural changes are discussed in this study.

Jana, Saumyadeep; Hovanski, Yuri; Grant, Glenn J.; Mattlin, Karl F.

2011-04-25

247

Evaluation of crack nucleation site and mechanical properties for friction stir welded butt joint in 2024-T3 aluminum alloy  

Microsoft Academic Search

In this paper, metallographic observations, hardness measurement, and static and fatigue tests were conducted to investigate\\u000a the discontinuity states which become crack nucleation sites in friction stir welded butt joints in 2-mm-thick 2024-T3 aluminum\\u000a alloy and static and fatigue properties of the joint. Because different types of surface finish can be used depending on the\\u000a application of the joint, several

Takao Okada; Masako Suzuki; Haruka Miyake; Toshiya Nakamura; Shigeru Machida; Motoo Asakawa

2010-01-01

248

Welding.  

ERIC Educational Resources Information Center

|This curriculum guide provides materials for a 12-unit secondary course in welding. Purpose stated for the flexible entry and exit course is to help students master manipulative skills to develop successful welding techniques and to gain an understanding of the specialized tools and equipment used in the welding field. Units cover oxyacetylene…

Lehigh County Area Vocational-Technical School, Schnecksville, PA.

249

A simple estimating method for reduction of welding residual stresses in thick welded joint from stress-relief annealing. Part 1: Development of the analytical method for relaxation tests and its applicability  

SciTech Connect

Stress-relief annealing (SR treatment) is often applied to relieve welding residual stresses in the fabrication process of pressure vessels etc. This study aims at development of an efficient method as simple as hand calculation to estimate reduction of residual stresses of very thick welded joint by SR treatment. In this first report, an estimating method is developed for relaxation tests, in uniaxial stress state, at changing and constant temperatures because the stress relaxation phenomenon is very similar to that observed in the SR treatment of a joint. Using the various relations between stress and strains in the relaxation tests, estimating equations are formulated in order to simply calculate the change of the stress. The results obtained by applying the equations are compared with the highly accurate analytical result based on the finite element method. Both results show such a good coincidence that the appropriateness of the adopted method is confirmed. In the next report, this method is extended to SR treatment of a very thick welded joint, of which the stress state and boundary condition are very complex.

Nakacho, K.; Ueda, Y. [Osaka Univ., Ibaraki, Osaka (Japan). Joint and Welding Research Inst.

1996-08-01

250

A Comparison of Creep Rupture Strength of Ferritic/Austenitic Dissimilar Weld Joints of Different Grades of Cr-Mo Ferritic Steels  

NASA Astrophysics Data System (ADS)

Evaluations of creep rupture properties of dissimilar weld joints of 2.25Cr-1Mo, 9Cr-1Mo, and 9Cr-1MoVNb steels with Alloy 800 at 823 K were carried out. The joints were fabricated by a fusion welding process employing an INCONEL 182 weld electrode. All the joints displayed lower creep rupture strength than their respective ferritic steel base metals, and the strength reduction was greater in the 2.25Cr-1Mo steel joint and less in the 9Cr-1Mo steel joint. Failure location in the joints was found to shift from the ferritic steel base metal to the intercritical region of the heat-affected zone (HAZ) of the ferritic steel (type IV cracking) with the decrease in stress. At still lower stresses, the failure in the joints occurred at the ferritic/austenitic weld interface. The stress-life variation of the joints showed two-slope behavior and the slope change coincided with the occurrence of ferritic/austenitic weld interface cracking. Preferential creep cavitation in the soft intercritical HAZ induced type IV failure, whereas creep cavitation at the interfacial particles induced ferritic/austenitic weld interface cracking. Micromechanisms of the type IV failure and the ferritic/austenitic interface cracking in the dissimilar weld joint of the ferritic steels and relative cracking susceptibility of the joints are discussed based on microstructural investigation, mechanical testing, and finite element analysis (FEA) of the stress state across the joint.

Laha, K.; Chandravathi, K. S.; Parameswaran, P.; Goyal, Sunil; Mathew, M. D.

2012-04-01

251

Azides and nitrides in joints welded by laser using N2 as covering gas  

NASA Astrophysics Data System (ADS)

A large amount of metals and alloys are successfully penetration welded by pulsed or cw laser. The laser welding process requires a gas flow (covering gas) to ensure adequate protection of the melt against atmospheric oxidation. The gas can be supplied in a variety of ways but in many cases the coaxial gas-laser geometry is used. This work is concerned with technological and structural investigations (using SEM and A.E.S. microanalysis) aimed at identifying any particular differences in the welds obtained using N2 instead of He as the covering gas. The investigations conducted on INCONEL 600 and stainless steel appear to provide conclusive evidence that N2 may be readily used as an alternative to He. Very recent works have studied some peculiarities (blanketing, transmission, and process efficiency) of N2 as a covering gas, when used in 2 kW CO2 laser welding. The influence of the covering gas in welding two stainless steels (AISI 304 and 430) and of a nickel alloy (INCONEL 600) using a 2 kW CO2 laser is examined.

Daurelio, Giuseppe; Dionoro, G.; Memola Capece Minutolo, F.; Panagopoulos, C.

1993-05-01

252

Fatigue life prediction of GTA welded AISI 304L cruciform joints with lack of penetration using local-stress approach  

Microsoft Academic Search

The influence of welding procedure on fatigue properties of gas tungsten arc welded (GTAW) AISI 304L load carrying cruciform joints, containing lack of penetration (LOP) has been studied using a crack initiation–propagation (I-P) method. The crack process normally comprises two major phases: (1) the crack initiation life (NI): and (2) the crack propagation life (Np). The local stress-life approach is

P Johan Singh; B Guha; D. R. G Achar

2003-01-01

253

Multiaxial fatigue of welded joints under in-phase and out-of-phase local strains and stresses  

Microsoft Academic Search

Welded cruciform-type specimens from fine-grained steel StE 290 and flange-tube as well as tube-tube joints from fine-grained steel StE 460 with unmachined and machined welds were investigated under biaxial constant-amplitude loading in the range 103 to 5 × 106 cycles to crack initiation and breakthrough respectively. In order not to interfere with residual stresses they were relieved by heat treatment.

C. M. Sonsino

1995-01-01

254

Creep damage evaluation of 9Cr–1Mo–V–Nb steel welded joints showing Type IV fracture  

Microsoft Academic Search

By conducting long-term creep rupture tests for 9Cr–1Mo–V–Nb (P91) steel welded joints, creep rupture properties and microstructures were examined. Creep rupture tests were conducted at three temperatures of 823, 873 and 923K, under applied stresses of 160–230, 80–130, and 40–80MPa, respectively. The rupture locations were found to shift from the weld metal at the higher stress condition to the fine-grained

Takashi Watanabe; Masaaki Tabuchi; Masayoshi Yamazaki; Hiromichi Hongo; Tatsuhiko Tanabe

2006-01-01

255

Joint strength prediction in a pulsed MIG welding process using hybrid neuro ant colony-optimized model  

Microsoft Academic Search

In this work, a pulsed metal inert gas welding (PMIGW) process is modeled by using a hybrid soft computing technique. Ant\\u000a colony optimization (ACO) and back-propagation neural network (BPNN) models are combined to predict the ultimate tensile strength\\u000a of butt-welded joints. A large number of experiments have been conducted, and comparative study shows that the hybrid neuro\\u000a ant colony-optimized model

N. Raghavendra; Rakshit Koranne; Sukhomay Pal; Surjya K. Pal; Arun K. Samantaray

2009-01-01

256

Elastic–plastic stress\\/strain response of friction stir-welded titanium butt joints using moiré interferometry  

Microsoft Academic Search

An experimental investigation is conducted to examine, evaluate, and characterize the fundamental elastic–plastic stress\\/strain response of friction stir-welded butt joints in thin-sheet, fine grain Ti–6Al–4V titanium alloy under normal tensile loading using the full-field optical strain analysis technique of moiré interferometry. It was found that the overall strength of friction stir-welded Ti–6Al–4V is comparable to the accepted values for pure

M. Ramulu; P. Labossiere; T. Greenwell

2010-01-01

257

Fatigue crack growth performance of peened friction stir welded 2195 aluminum alloy joints at elevated and cryogenic temperatures  

Microsoft Academic Search

The effects of various surface treatments on fatigue crack growth and residual stress distributions in friction stir welded 2195 aluminum alloy joints were investigated. The objective was to understand the degree to which residual stress treatments can reduce fatigue crack growth rates, and enhance fatigue life of friction stir welded components. Specimens were fabricated from 12.5mm thick 2195-T8 aluminum plate,

Omar Hatamleh; Michael Hill; Scott Forth; Daniel Garcia

2009-01-01

258

Enhancement of the durability of structural steels and their welded joints by plastic deformation  

Microsoft Academic Search

Conclusions  The fatigue and corrosion-fatigue resistance of low-alloy steels increases as degree of plastic prestraining increases to\\u000a 29%. The resistance of the 08kp steel prestrained and hardened by surface plastic deformation and its welded joints to fatigue\\u000a and corrosion-fatigue fracture is higher than for the 08GSYuT alloyed steel. The procedures of pneumatic shot blasting and\\u000a shot blasting prove to be efficient

M. P. Berezhnyts’ka; H. P. Huslyakova; V. I. Tkachov

2000-01-01

259

Formation of intermetallic phases in diffusion-welded joints of aluminium and magnesium alloys  

Microsoft Academic Search

Basic research has been done on diffusion-welded joints with the overall aim of an adjusted interface design. The phase formation\\u000a of aluminium alloy\\/magnesium alloy bonds has been revealed by X-ray diffraction, energy-dispersive spectroscopy and electron\\u000a back-scatter diffraction. The presence of Al12Mg17 and Al3Mg2 phases in a bi-layer has been confirmed. The distribution and microstructure of the formed intermetallics and the

D. Dietrich; D. Nickel; M. Krause; T. Lampke; M. P. Coleman; V. Randle

2011-01-01

260

Experimental study on fatigue performance and damage model of aluminum alloy welding joints for high-speed train car body  

NASA Astrophysics Data System (ADS)

In order to realize lightweight, security and comfort, the aluminum alloy profile becomes the first choice of the high speed train carbody. The fatigue experiments are carried on the typical welding joins such as butt, fillet, cruciform and lap joins. The fatigue limits and P-S-N curves are obtained. The non-linearity cumulative damage model is proposed taking loading sequences for consideration and the two-level loading experiments on butt and fillet joints are studied to verify the feasibility of the damage model. The fatigue life of carbody is predicted based on the proposed damage model and the online dynamic stress test results. The results show that the fatigue life calculated by non-linearity damage model is close to that by modified Miner law and 22% less than that by Miner law.

Wang, Wenjing; Li, Qiang; Liu, Zhiming; Wang, Binjie

2009-12-01

261

Evaluations of mixed-mode stress intensity factors for load-carrying fillet welded cruciform joints using the least-squares method  

Microsoft Academic Search

This study presents the numerical and experimental applications of using the least-squares method (LSM) to evaluate the mixed-mode stress intensity factors (SIFs) of load-carrying fillet welded cruciform joints. In the numerical application, fillet welded cruciform joints of different combinations of geometric parameters (including weld leg size, initial lack of penetration size, and plate thickness) were systematically studied using the finite

Hsin-Yang Chung; Rong-Shiuan Lin; Kun-Jhen Lin

2011-01-01

262

Microstructural characteristics and mechanical properties of friction stir welded joints of Ti–6Al–4V titanium alloy  

Microsoft Academic Search

The ?+? titanium alloy, Ti–6Al–4V, was friction stir welded at a constant tool rotation speed of 400rpm. Defect-free welds were successfully obtained with welding speeds ranging from 25 to 100mm\\/min. The base material was mill annealed with an initial microstructure composed of elongated primary ? and transformed ?. A bimodal microstructure was developed in the stir zone during friction stir

H. J. Liu; L. Zhou; Q. W. Liu

2010-01-01

263

The effect of process parameters and tool geometry on mechanical properties of friction stir welded aluminum butt joints  

Microsoft Academic Search

In Friction Stir Welding (FSW), process parameters and tool geometry play a fundamental role in obtaining desirable mechanical\\u000a properties and microstructures in the welded zone. The results of experimental activity on friction stir welding of aluminum\\u000a alloys, focused on the above mentioned aspects, are reported in the present paper. The experimental campaign was performed\\u000a on sheets 5 mm thick of

G. D’Urso; E. Ceretti; C. Giardini; G. Maccarini

2009-01-01

264

Re-weldability of neutron-irradiated stainless steels studied by multi-pass TIG welding  

Microsoft Academic Search

Weldability of neutron-irradiated stainless steel (SS) has been studied by multi-pass bead-on-plate and build-up tungsten inert gas (TIG) welding, simulating the repair-welding of reactor components. Specimens were submerged arc welding (SAW) joint of Type 304 SS containing 0.5 appm helium (1.8 appm in the SAW weld metal). Sound welding could be obtained by one- to three-pass welding on the plates

K. Nakata; M. Oishi; M. Koshiishi; T. Hashimoto; H. Anzai; Y. Saito; W. Kono

2002-01-01

265

Characterization of Microstructures across the Heat-Affected Zone of the Modified 9Cr-1Mo Weld Joint to Understand Its Role in Promoting Type IV Cracking  

NASA Astrophysics Data System (ADS)

In the postweld heat-treated (PWHT) fusion welded modified 9Cr-1Mo steel joint, a soft zone was identified at the outer edge of the heat-affected zone (HAZ) of the base metal adjacent to the deposited weld metal. Hardness and tensile tests were performed on the base metal subjected to soaking for 5 minutes at temperatures below Ac1 to above Ac3 and tempering at the PWHT condition. These tests indicated that the soft zone in the weld joint corresponds to the intercritical region of HAZ. Creep tests were conducted on the base metal and cross weld joint. At relatively lower stresses and higher test temperatures, the weld joint possessed lower creep rupture life than the base metal, and the difference in creep rupture life increased with the decrease in stress and increase in temperature. Preferential accumulation of creep deformation coupled with extensive creep cavitation in the intercritical region of HAZ led to the premature failure of the weld joint in the intercritical region of the HAZ, commonly known as type IV cracking. The microstructures across the HAZ of the weld joint have been characterized to understand the role of microstructure in promoting type IV cracking. Strength reduction in the intercritical HAZ of the joint resulted from the combined effects of coarsening of dislocation substructures and precipitates. Constrained deformation of the soft intercritical HAZ sandwich between relatively stronger constitutes of the joint induced creep cavitation in the soft zone resulting in premature failure.

Laha, K.; Chandravathi, K. S.; Parameswaran, P.; Rao, K. Bhanu Sankara; Mannan, S. L.

2007-01-01

266

Formation mechanism of linear friction welded Ti-6Al-4V alloy joint based on microstructure observation  

SciTech Connect

The microstructure of the linear friction welded Ti-6Al-4V titanium alloy joint was investigated by optical microscope, scanning electronic microscope and transmission electron microscope. Results show that the dynamic recovery and recrystallization resulting from the intensive plastic deformation and fast heating and cooling processes during linear friction welding account for the superfine {alpha} + {beta} grains in the weld center. Fine {alpha} grains distribute in the {beta} matrix or at the boundaries of {beta} grains. A mass of dislocations networks and metastructures present within the {alpha} and {beta} grains. - Research Highlights: {yields} TEM is employed in the analysis. {yields} The dynamic recovery is the main mechanism in thermal deformation of TC4. {yields} Superfine grains in the weld result from dynamic recovery and dynamic recrystallizaion, but the recrystallization is inadequate.

Ma Tiejun; Chen Tao, E-mail: ctwc-13@163.com; Li Wenya; Wang Shiwei; Yang Siqian

2011-01-15

267

Numerical study of local PWHT condition for EB welded joint between first and side walls in ITER-TBM  

NASA Astrophysics Data System (ADS)

The stress relaxation behavior of post-weld heat treatment (PWHT) F82H was examined to determine the appropriate PWHT condition for electron beam welded joints between the first and side walls of the International Thermonuclear Experimental Reactor (ITER) test blanket module. Thermal elastic-plastic creep finite element analyses were conducted assuming Norton creep law. Uniform heat treatment and four types of local heating near the weld line were studied. Numerical analyses concluded that the welding residual stress could be reduced by a local heat treatment near the penetration from both the first and side walls, where the cooling area and rate could be controlled. In addition, the stress on the channel surface in the first wall was found to decrease to less than 50 MPa with the appropriate local PWHT.

Serizawa, Hisashi; Nakamura, Shinichiro; Tanigawa, Hiroyasu; Ogiwara, Hiroyuki; Murakawa, Hidekazu

2013-11-01

268

An investigation of the residual stress characterization and relaxation in peened friction stir welded aluminum–lithium alloy joints  

Microsoft Academic Search

In this investigation the residual stresses generated from friction stir welded (FSW) 2195 aluminum–lithium alloy joints were characterized. The results derived from this research revealed significant levels of tensile residual stresses at the surface and throughout the thickness of the FSW samples. Furthermore, residual stress relaxation at the surface and throughout the thickness of the samples was assessed for laser

Omar Hatamleh; Iris V. Rivero; Shayla E. Swain

2009-01-01

269

Optimising the shielded metal arc welded cruciform joint dimensions of ASTM 517 F grade steels containing LOP defects  

Microsoft Academic Search

A new method was developed to optimise the dimensions of shielded metal arc welded (SMAW) cruciform joints, containing lack of penetration (LOP) defects, to attain maximum fatigue lives. High strength, quenched and tempered steel (ASTM 517 F grade) was used as the base material throughout the investigation. Design of experiments (DoE) concept was used to optimise the required number of

V. Balasubramanian; B. Guha

1999-01-01

270

Fatigue life prediction of shielded metal arc welded cruciform joints containing LOP defects by a mathematical model  

Microsoft Academic Search

A new mathematical model is developed to predict the fatigue life of Shielded Metal Arc Welded (SMAW) cruciform joints containing Lack of Penetration (LOP) defect. High strength, quenched and tempered steel (ASTM 517 ‘F’ Grade) is used as the base material throughout the investigation. Four factors, five level, central composite, rotatable design matrix is used to optimise the required number

V. Balasubramanian; B. Guha

1999-01-01

271

Influences of shielded metal arc welded cruciform joint dimensions on toe crack failures of pressure vessel grade steels  

Microsoft Academic Search

A mathematical model has been developed to predict the fatigue life of Shielded Metal Arc Welded (SMAW) cruciform joints failing from toe region. High strength, quenched and tempered steel (ASTM 517 ‘F’ Grade) has been used as the base material throughout the investigation. Design of Experiments (DoE) concept has been used to optimise the required number of experiments. Fatigue experiments

V Balasubramanian; B Guha; A. S. J Swamidas; R Seshadri

2000-01-01

272

Fatigue life prediction of gas metal arc welded crucifrom joints of AA7075 aluminium alloy failing from root region  

Microsoft Academic Search

Empirical relationship was developed to predict the fatigue life of gas metal arc welded (GMAW) cruciform joints failing from root region. High strength, age hardenable aluminium alloy of AA7075-T6 grade was used as the base material. The design of experiments concept was used to optimize the required number of fatigue testing experiments. Fatigue experiment was conducted in a servo hydraulic

B. RAVINDRA; T. SENTHIL KUMAR; V. BALASUBRAMANIAN

2011-01-01

273

C-ring stress corrosion test for Inconel 600 and Inconel 690 sleeve joint welded by Nd:YAG laser  

Microsoft Academic Search

C-ring stress corrosion test for Inconel 600 and Inconel 690 sleeve joint welded by Nd:YAG laser were carried out to evaluate the applicability of the technique in the repair of heat exchanger tube of nuclear power plant. Corrosion test were carried out mainly in caustic solution. The applied stresses range between 207 and 414 MPa at 348 °C and the

Jae-Do Kim; Ju-Hong Moon

2004-01-01

274

Changes to the microstructure of joints of welded iron superalloys IN 519 and H39WM during operation  

Microsoft Academic Search

Steam reforming is one method of producing hydrogen. The endothermic decomposition process of mixtures consisting of methane and water vapour under pressures of up to 4.0 MPa is conducted at a temperature of up to 780°C in austenite pipes cast centrifugally and filled with nickel catalytic agent. The results of microstructure tests on the welded joints of centrifugally cast catalytic pipes,

Walenty Jasi?ski; Pawe? Zawada

2011-01-01

275

Effect of welding parameters on mechanical and microstructural properties of dissimilar AA6082–AA2024 joints produced by friction stir welding  

Microsoft Academic Search

The effect of processing parameters on the mechanical and microstructural properties of dissimilar AA6082–AA2024 joints produced by friction stir welding was analysed in this study. Different samples were produced by varying the advancing speeds of the tool as 80 and 115mm\\/min and by varying the alloy positioned on the advancing side of the tool. In all the experiments the rotating

P. Cavaliere; A. De Santis; F. Panella; A. Squillace

2009-01-01

276

Laser welding of metals  

Microsoft Academic Search

The physical processes associated with laser welding and the existing laser welding techniques are reviewed. Attention is given to the characteristics of joint formation during the welding by pulsed and continuous-wave lasers; the principal welding parameters and their effect on the melting characteristics and weld quality; and the principal types of equipment used for laser welding. The discussion also covers

Aleksandr G. Grigor'iants; Igor'n. Shiganov

1988-01-01

277

Multiscale characterization of deformation mechanisms in the weld joint of a nickel-based superalloy  

SciTech Connect

Multiscale plastic deformation in the heat affected zone (HAZ) of a Ni-based single crystal superalloy has been characterized using white microbeam synchrotron diffraction measurements together with OIM imaging, electron and optical microscopy. Characteristic length scales on the macro, meso and nano scale are determined. Dissolution of the gamma' - phase particles during heating and secondary precipitation of gamma' during cooling is found, as well as formation and multiplication of dislocations. This process is more intense as one approaches the fusion line (FL). In the regions immediately neighboring the FL, gamma' - phase particles dissolve completely and re-precipitate from the solid solution in the form of very small (10-20nm) particles. In the immediate vicinity of the FL, the temperature gradient and the rate of it's change reaches maximal values and causes the formation of large amounts of dislocations. Dislocations are concentrated in the gamma matrix of the single crystal superalloy. X-ray Laue diffraction (both conventional and microbeam) and electron microscopy show that alternating dislocations slip systems dominate in the HAZ with Burgers vector b=[110] and dislocation lines [1-12] and [1-1-2] ; or b=[-110], dislocation lines [112] and [11-2] . Each of these two dislocation groups forms two Z-shaped dislocation lines fluctuating around two cubic directions [100] and [010]. Local lattice rotations in different zones of the weld joint are linking with the microslip events in different zones of the weld.

Barabash, Oleg M [ORNL; Horton Jr, Joe A [ORNL; Babu, Sudarsanam S [ORNL; Vitek, John Michael [ORNL; David, Stan A [ORNL; Ice, Gene E [ORNL; Barabash, Rozaliya [ORNL

2005-01-01

278

Stress Corrosion Cracking Behavior of Peened Friction Stir Welded 2195 Aluminum Alloy Joints  

NASA Astrophysics Data System (ADS)

The surface treatment techniques of laser and shot peening were used to investigate their effect on stress corrosion cracking (SCC) in friction stir welded (FSW) 2195 aluminum alloy joints. The investigation consisted of two parts: the first part explored the peening effects on slow strain rate testing (SSRT) in a 3.5% NaCl solution, while the second part investigated the effects of peening on corrosion while submerged in a 3.5% NaCl solution with no external loads applied. For the SSRT, the laser-peened samples demonstrated superior properties to the other samples, but no signs of corrosion pitting or SCC were evident on any of the samples. For the second part of the study, the FSW plates were inspected periodically for signs of corrosion. After 60 days there were signs of corrosion pitting, but no stress corrosion cracking was noticed in any of the peened and unpeened samples.

Hatamleh, Omar; Singh, Preet M.; Garmestani, Hamid

2009-06-01

279

Fatigue Assessment and LEFM Analysis of Cruciform Joints Fabricated with Different Welding Processes  

Microsoft Academic Search

In this study fatigue testing and defect assessment were carried out on specimens welded with robotic and manual welding using flux cored (FCAW) and metal cored (MCAW) filler materials in order to study the effect of the welding method on the fatigue strength and weld quality. Thirteen different batches were investigated of which two was shot peened before fatigue testing.

Z. Barsoum; B. Jonsson

280

A simple estimating method for reduction of welding residual stresses in thick welded joint from stress-relief annealing. Part 1: Development of the analytical method for relaxation tests and its applicability  

Microsoft Academic Search

Stress-relief annealing (SR treatment) is often applied to relieve welding residual stresses in the fabrication process of pressure vessels etc. This study aims at development of an efficient method as simple as hand calculation to estimate reduction of residual stresses of very thick welded joint by SR treatment. In this first report, an estimating method is developed for relaxation tests,

K. Nakacho; Y. Ueda

1996-01-01

281

Effect of welding processes on tensile properties of AA6061 aluminium alloy joints  

Microsoft Academic Search

The present investigation is aimed at to study the effect of welding processes such as GTAW, GMAW and FSW on mechanical properties\\u000a of AA6061 aluminium alloy. The preferred welding processes of these alloys are frequently gas tungsten arc welding (GTAW)\\u000a and gas metal arc welding (GMAW) due to their comparatively easier applicability and better economy. In this alloy, the weld

A. K. Lakshminarayanan; V. Balasubramanian; K. Elangovan

2009-01-01

282

Weld penetration and defect control  

SciTech Connect

Highly engineered designs increasingly require the use of improved materials and sophisticated manufacturing techniques. To obtain optimal performance from these engineered products, improved weld properties and joint reliability are a necessarily. This requirement for improved weld performance and reliability has led to the development of high-performance welding systems in which pre-programmed parameters are specified before any welding takes place. These automated systems however lack the ability to compensate for perturbations which arise during the welding process. Hence the need for systems which monitor and control the in-process status of the welding process. This report discusses work carried out on weld penetration indicators and the feasibility of using these indicators for on-line penetration control.

Chin, B.A.

1992-05-15

283

Effect of Welding Consumables on Fatigue Performance of Shielded Metal Arc Welded High Strength, Q&T Steel Joints  

Microsoft Academic Search

Quenched and Tempered (Q&T) steels are widely used in the construction of military vehicles due to their high strength-to-weight\\u000a ratio and high hardness. These steels are prone to hydrogen-induced cracking in the heat affected zone (HAZ) after welding.\\u000a The use of austenitic stainless steel consumables to weld the above steel was the only remedy because of higher solubility\\u000a for hydrogen

G. Magudeeswaran; V. Balasubramanian; G. Madhusudhan Reddy

2009-01-01

284

Parametric Analysis of the Stresses in a Cruciform Axially Loaded Welded Joint Analisi Parametrica Delle Sollecitazioni in UN Giunto Saldato a Croce Sollecitato Assialmente.  

National Technical Information Service (NTIS)

The influence of the geometry on the stresses present in a cruciform welded joint axially loaded was investigated. Complete penetration was assumed for the analysis and the state of stress at the surface of the main plate, especially at the weld-toe, was ...

B. Atzori V. Dattoma

1976-01-01

285

The structure of the superheated region of the heat-affected zone of the welded joint in heat-resisting pearlitic steels  

Microsoft Academic Search

Investigations were carried out into the formation of Widmanstatten ferrite in the structure of the section of incomplete recrystallization of the heat-affected zone of welded joints in heat-resisting pearlitic steels in the conditions of heating during welding.

V. V. Dmitrik; E. D. Grinchenko; T. O. Syrenko

2011-01-01

286

A comprehensive investigation on the effects of laser and shot peening on fatigue crack growth in friction stir welded AA 2195 joints  

Microsoft Academic Search

The effects of various surface treatment techniques on the fatigue crack growth performance of friction stir welded 2195 aluminum alloy were investigated. The objective was to reduce fatigue crack growth rates and enhance the fatigue life of welded joints. The crack growth rates were assessed and characterized for different peening conditions at a stress ratio (R) of 0.1, and 0.7.

Omar Hatamleh

2009-01-01

287

The Influence Exerted by Weld Seam Throat and Plate Thickness on the Fatigue Strength of Weld Joints Made by Means of Fillet Welds.  

National Technical Information Service (NTIS)

An investigation was carried out to determine the influence exerted by weld seam throat and plate thickness on the fatigue strength of the transition areas of fillet welds. The statistical test program covered angular test pieces made from grade MRSt 37-2...

E. Haibach R. Olivier W. Ritter

1978-01-01

288

On the occurrence of Portevin-Le Chatelier effect in fusion welded 2091 Al-Li based alloy joints  

SciTech Connect

Al-Li based alloys are characterized by their lower density and higher stiffness, in comparison with conventional aluminum alloys. This makes the former very attractive for replacing the latter in structural and cryogenic applications, particularly in aeronautic and aerospace industries. The potential use of lithium-bearing also has stimulated studies on the weldability of these alloys as well as on the mechanical properties of the resulting welded joints. Al-Li-Cu-Mg alloy systems studied by Gomiero were found to exhibit serrations in their stress-strain curves, indicating the occurrence of Portevin-Le Chatelier (PLC) effects during plastic flow in these systems. The present study was therefore undertaken to determine the effect of fusion welding on the uniaxial tensile behavior of a 2091 (Al-Li-Cu-Mg-Zr) alloy. Microstructural aspects pertinent to the PLC effect are to be emphasized and the influence of post-weld heat treatment is to be presented and discussed.

Vidal, A.C.; Darwish, F.A.; Solorzano, I.G. [Catholic Univ., Rio de Janeiro (Brazil)

1995-09-01

289

Comparative study of high-strength steel weld metals obtained by the SMAW and FCAW processes for offshore applications and mooring chains  

Microsoft Academic Search

A comparative study of the clad electrode and tubular wire processes was carried out, looking at the mechanical and micro-structural properties of weld metals of high-resistance steel, in the ‘as-welded’ and ‘stress-relief heat treatment’ (PWHT) conditions. The results show that the procedures adopted for welding with tubular wire and clad electrodes allow satisfactory levels of mechanical resistance to be obtained,

Humberto N. Farneze; Jorge Carlos F. Jorge; Luís Felipe G. de Souza; Ivaní de S. Bott

2010-01-01

290

Welding.  

ERIC Educational Resources Information Center

|This curriculum guide is intended to assist vocational instructors in preparing students for entry-level employment as welders and preparing them for advanced training in the workplace. The package contains an overview of new and emerging welding technologies, a competency/skill and task list, an instructor's guide, and an annotated bibliography.…

Baldwin, Harold; Whitney, Gregory

291

Welding.  

ERIC Educational Resources Information Center

|The curriculum guide for welding instruction contains 16 units presented in six sections. Each unit is divided into the following areas, each of which is color coded: terminal objectives, specific objectives, suggested activities, and instructional materials; information sheet; transparency masters; assignment sheet; test; and test answers. The…

Cowan, Earl; And Others

292

Stress corrosion cracking susceptibility of friction stir welded AA7075–AA6056 dissimilar joint  

Microsoft Academic Search

Two aluminium alloys, AA7075 and AA6056, were friction stir welded, with the AA7075 alloy placed on the advancing side of the welding tool. Microstructural observations revealed the development of a recrystallised fine-grained weld nugget, with two different grain sizes, resulting from the two different base materials. Slow strain rate tensile (SSRT) tests in air have shown that the weld nugget

P. Bala Srinivasan; W. Dietzel; R. Zettler; J. F. dos Santos; V. Sivan

2005-01-01

293

Development of Residual Stress Improvement for Nuclear Pressure Vessel Instrumentation Nozzle Weld Joint (P-43+P-8) by Means of Induction Heating  

SciTech Connect

As a counter measurement of intergranular stress corrosion cracking (IGSCC) in boiling water reactors, the induction heating stress improvement (IHSI) has been developed as a method to improve the stress factor, especially residual stresses in affected areas of pipe joint welds. In this method, a pipe is heated from the outside by an induction coil and cooled from the inside with water simultaneously. By thermal stresses to produce a temperature differential between the inner and outer pipe surfaces, the residual stress inside the pipe is improved compression. IHSI had been applied to weld joints of austenitic stainless steel pipes (P-8+P-8). However IHSI had not been applied to weld joints of nickel-chromium-iron alloy (P-43) and austenitic stainless steel (P-8). This weld joint (P-43+P-8) is used for instrumentation nozzles in nuclear power plants' reactor pressure vessels. Therefore for the purpose of applying IHSI to this one, we studied the following: Investigation of IHSI conditions (Essential Variables); Residual stresses after IHSI; Mechanical properties after IHSI. This paper explains that IHSI is sufficiently effective in improvement of the residual stresses for this weld joint (P-43+P-8), and that IHSI does not cause negative effects by results of mechanical properties, and IHSI is verified concerning applying it to this kind of weld joint. (authors)

Takuro Terajima; Takashi Hirano [Ishikawajima-Harima Heavy Industies Co., Ltd (Japan)

2006-07-01

294

Robotic welding  

SciTech Connect

The purpose of this book is to provide the reader with the latest up-to-date information on robotic welding, associated components, and systems. This information has been compiled on automatic robotic arc welding systems which are presently employed and being worked on for future applications along with various adaptive control techniques and welt joint seam,-tracking systems being investigated for continuous robotic arc welding. In addition to arc welding, robotic resistance welding and laser welding systems and applications are presented with the idea of illustrating detailed knowledge on the most established and the newest robotic integrated systems, respectively.

Lane, J.D.

1986-01-01

295

A PARAMETRIC STUDY ON FATIGUE LIFE BEHAVIOR OF SPOT WELDED JOINTS  

Microsoft Academic Search

Despite the availability of other joining methods such as laser beam welding, bolted, riveted, and adhesive bonding, resistance spot welding (RSW) remains the primary method to join panels especially in automotive, railroad, and airplane structures, which contain hundreds, even thousands of spot welds. In service, mechanical components usually experience cyclic loading. This makes fatigue failure prevention the foremost design requirement.

Ahmet Hanifi ERTAS; Fazil Onder SONMEZ

296

Influence of Control Parameters on the Joint Tracking Performance of a Coaxial Weld Vision System.  

National Technical Information Service (NTIS)

The first phase of a series of evaluations of a vision-based welding control sensor for the Space Shuttle Main Engine Robotic Welding System is described. The robotic welding system is presently under development at the Marshall Space Flight Center. This ...

K. J. Gangl J. L. Weeks

1985-01-01

297

Predicting weld toe stress concentration factors for T and skewed T-joint plate connections  

Microsoft Academic Search

The results of linear elastic finite element analyses of stress concentration factors (SCFs) of 80 weld toe T-butt plate geometries are presented in parametric form for tension and pure bending loading. The closed form solutions describe the stress state of the two-dimensional plane stress models studied in terms of weldment angle, weld root radius, weld attachment width and plate thickness.

F. P. Brennan; P. Peleties; A. K. Hellier

2000-01-01

298

Influence of flux cored arc welded cruciform joint dimensions on fatigue life of ASTM 517 `F' grade steels  

Microsoft Academic Search

A mathematical model has been developed to predict the fatigue life of flux-cored arc-welded (FCAW) cruciform joints containing lack of penetration (LOP) defects. High strength, quenched and tempered steel (ASTM 517 `F' grade) has been used as the base material throughout the investigation. The design of experiments (DoE) concept has been used to optimize the required number of experiments. Fatigue

V Balasubramanian; B Guha

1998-01-01

299

Fatigue life prediction of gas tungsten arc welded AISI 304L cruciform joints with different LOP sizes  

Microsoft Academic Search

Fatigue life evaluations have been carried out on gas tungsten arc welded (GTAW) load-carrying cruciform joints of AISI 304L stainless steel with lack of penetration (LOP) using conventional S-N and crack initiation-propagation (I-P) methods. The crack process normally comprises two major phases: (1) the crack initiation life (Ni): and (2) the crack propagation life (Np). The local stress-life approach is

P. Johan Singh; D. R. G Achar; B Guha; Hans Nordberg

2003-01-01

300

A new model to predict the fatigue life of flux cored arc welded cruciform joints containing LOP defects  

Microsoft Academic Search

A mathematical model has been developed to predict the fatigue life of Flux Cored Arc Welded (FCAW) cruciform joints containing\\u000a Lack of Penetration (LOP) defect. High strength, Quenched and Tempered steel ASTM 517 ‘F’ Grade has been used as the base\\u000a material throughout the investigation. Two level, full factorial technique has been applied to design the experiments. The\\u000a model has

V. Balasubramanian; B. Guha

1998-01-01

301

Tensile, creep and fatigue properties of low-fluence neutron-irradiated welded joints DIN 1. 4948  

Microsoft Academic Search

Welded joints of stainless steel DIN 1.4948, which is similar to AISI Type 304, have been irradiated at 723 and 823 K up to fluences of 1 X 10²³ neutrons (n) X m⁻² and 5 X 10²⁴ n X m⁻² (E>0.1 MeV). Tension and creep tests show considerable irradiation embrittlement, depending on fluence, test temperature, and strain rate. Creep strain

M. I. de Vries; B. van der Schaaf

1981-01-01

302

Stress-corrosion cracking behavior of laser-welded aluminum-lithium sheet joints in salt solution  

Microsoft Academic Search

Stress-corrosion cracking (SCC) of laser welded Al-Li alloy joints was investigated at ambient temperature in an aqueous solution of 3.5 wt pct NaCl. Fracture mechanics was used to study the environmentally enhanced crack growth at the highly stress concentrated tip area of fatigue precracked specimens. The results show that SCC occurred at a potential of -0.725 volts. The accepted relationship

Lin

1989-01-01

303

Effect of prior microstructure on microstructure and mechanical properties of modified 9Cr–1Mo steel weld joints  

Microsoft Academic Search

Strength of modified 9Cr–lMo steel, which is used in the normalized and tempered condition, increases with increase in solutionising temperature with a corresponding reduction in percentage elongation. There is an increase in the prior-austenite grain size with increase in solutionising temperature. The heat-affected zone (HAZ) of the weld joints prepared from this material that has been subjected to solutionising at

C. R. Das; S. K. Albert; A. K. Bhaduri; G. Srinivasan; B. S. Murty

2008-01-01

304

Numerical simulation of mechanical controlling parameters for Type IV cracking on the welding joints of martensitic heat-resistant steel  

Microsoft Academic Search

The maximum principal stress, von Mises equivalent stress and equivalent creep strain in the welding joint of martensitic\\u000a heat-resistant steel (9Cr1MoVNb) are simulated by finite-element method (FEM) under the condition of 600°C and applied stress\\u000a of 80 MPa. The results show that the maximum principal stress and von Mises equivalent stress are high on the curved points\\u000a of two sides

Jian-Qiang Zhang; Bing-Yin Yao; Tai-Jiang Li; Fu-Guang Liu; Ying-Lin Zhang

2010-01-01

305

Laser net shape welding  

Microsoft Academic Search

Over the last 40 years of laser welding practice, weld bead geometry always experiences a section of the weld bead slightly above or below the parent material surface. In this paper, a new concept – net shape welding is introduced, whereby the weld joint fusion zone is flat to the parent material surface. Experimental work was carried out to demonstrate

Lin Li; Ramadan Eghlio; Sundar Marimuthu

2011-01-01

306

Optimization of pulsed GTA welding process parameters for the welding of AISI 304L stainless steel sheets  

Microsoft Academic Search

Optimization of pulsed gas tungsten arc welding (pulsed GTAW) process parameters was carried out to obtain optimum weld bead\\u000a geometry with full penetration in welding of stainless steel (304L) sheets of 3 mm thickness. Autogenuous welding with square\\u000a butt joint was employed. Design of experiments based on central composite rotatable design was employed for the development\\u000a of a mathematical model correlating

P. K. Giridharan; N. Murugan

2009-01-01

307

An experimental study on friction welding of medium carbon and austenitic stainless steel components  

Microsoft Academic Search

In the presented study, AISI 1040 medium carbon steel and AISI 304 austenitic stainless steel parts were joined by friction welding. The welding process was carried out under optimized conditions using statistical approach. Tension tests were applied to welded parts to obtain the strength of the joints. Fatigue properties were additionally obtained experimentally under fluctuated tensile loads. Finally, notch impact

Mümin Sahin; H. Erol Akata

2004-01-01

308

The influence of hydrogen charging on the notch tensile properties and fracture behaviour of dissimilar weld joints of advanced Cr–Mo–V and Cr–Ni–Mo creep-resistant steels  

Microsoft Academic Search

The influence of hydrogen charging on the room-temperature tensile properties and fracture behaviour of two dissimilar weld joints has been investigated. The weld joints were either ferritic\\/ferritic (T91\\/STN15128) or ferritic\\/austenitic (T91\\/TP316H). The tensile tests were carried out using the samples with a circumferential notch. The position of notch was individually located in different weld joint regions, either in the heat-affected

J. Blach; L. Falat; P. Ševc

2011-01-01

309

Thermal modeling and adaptive control of scan welding  

SciTech Connect

This article introduces scan welding as a redesign of classical joining methods, employing automation technology to ensure the overall geometric, material and mechanical integrity of the joint. This is obtained by real-time control of the welding temperature field by a proper dynamic heat input distribution on the weld surface. This distribution is implemented in scan welding by a single torch, sweeping the joint surface by a controlled reciprocating motion, and power adjusted by feedback of infrared temperature measurements in-process. An off-line numerical simulation of the thermal field in scan welding is established, as well as a linearized multivariable model with real-time parameter identification. An adaptive thermal control scheme is thus implemented and validated--both computationally and experimentally on a robotic plasma arc welding (PAW) station. The resulting thermal features related to the generated material structure and properties of the joint are finally analyzed in scan welding tests and simulations.

Doumanidis, C.C. [Tufts Univ., Medford, MA (United States). Dept. of Mechanical Engineering

1998-11-01

310

Effect of welding speed on mechanical strength of friction welded joint of YSZ–alumina composite and 6061 aluminum alloy  

Microsoft Academic Search

Successful application of ceramics in many devices and structures requires some type of ceramic metal joining. All applications require a high-strength metal–ceramic bond. Even successful joint formation does not guarantee mechanical soundness of the joint. The inherent differences in physical properties between the ceramic and the metal make it extremely difficult to find an effective joining process that maintains the

M. B. Uday; M. N. Ahmad Fauzi; H. Zuhailawati; A. B. Ismail

2011-01-01

311

The influence of output current on the tensile strength of laser-welded titanium joints  

Microsoft Academic Search

The objective of this study was to examine the influences of the laser output current on the tensile strength of laser-welded\\u000a titanium bar. Titanium bars of 3 mm in diameter were perpendicularly cut to 30 mm in length for the laser welding. Two bars\\u000a were fixed to each other with a jig and welded vertically with the light of a

Dae Hee Won; Tae Sung Bae; Shoji Ohkawa; Fumio Watari

2003-01-01

312

Mechanical properties of laser-welded cast titanium joints under different conditions  

Microsoft Academic Search

Statement of the problem. Data on optimal conditions for laser welding commercial pure cast titanium used in dental restorations are sparse and not well established.Purpose. The mechanical properties of laser-welded cast commercially pure titanium under different laser welding conditions were evaluated to find the optimal parameters in terms of duration and voltage (energy level).Material and methods. Fifty-seven cast pure titanium

Tsongi Chai; Chia Kai Chou

1998-01-01

313

Effect of vibratory weld conditioning on welded valve properties  

Microsoft Academic Search

The approach to improve the quality of full welded valve by the application of vibratory weld conditioning (VWC) was investigated in this paper. The effect of VWC on the welded joint properties was studied. Cylinders with different thicknesses were welded by submerged arc welding (SAW). The experiment results show that the vibration applied during welding generally reduces the residual deformation

Lu Qinghua; Chen Ligong; Ni Chunzhen

2008-01-01

314

Features of misoriented structures in a copper-copper bilayer plate obtained by explosive welding  

NASA Astrophysics Data System (ADS)

Structures induced by deformation in the narrow zone of a contact between two copper plates that is prepared by explosive welding are systematically investigated at the micro-, meso-, and macrolevels. Plastic jets, regions of metal plastic flow anomalous localization, are discovered in areas adjacent to the contact surface. The defect structure of the plastic jets is examined by transmission electron microscopy and electron backscatter diffraction. It is shown that at the mesolevel the plastic jets are regions with a heavily fragmented structure. The statistics of the fragment distribution over misorientations and transverse sizes is studied.

Rybin, V. V.; Ushanova, E. A.; Zolotorevskii, N. Yu.

2013-09-01

315

Fatigue Life Improvement for Cruciform Welded Joint by Mechanical Surface Treatment using Hammer Peening and UNSM  

Microsoft Academic Search

For the improvement of fatigue strength of welded structures, mechanical post treatments have been applied in various industrial fields and have in most cases been founded to give substantial increases in their fatigue lives. These methods, generally, consist of the modification of weld toe geometry and the introduction of compressive residual stresses. In mechanical surface treatments, e.g. PHP (pneumatic hammer

Seung-Ho Han; Jeong-Woo Han; Yong-Yun Nam; In-Ho Cho

2009-01-01

316

Reduction method for residual stress of welded joint using harmonic vibrational load  

Microsoft Academic Search

Welding is widely used for construction of many structures. Since welding is a process using locally given heat, residual stress is generated near the bead. Tensile residual stress degrades fatigue strength. Some reduction methods of residual stress have been presented and, for example, heat treatment and shot peening are practically used. However, those methods need special tools and are time

Shigeru Aoki; Tadashi Nishimura; Tetsumaro Hiroi; Seiji Hirai

2007-01-01

317

Modeling of temperature distribution in ultrasonic welding of thermoplastics for various joint designs  

Microsoft Academic Search

Use of engineering plastics in structural and non-structural applications is rapidly increasing. As the demand for plastics increases so does the requirements for joining. Of the many techniques that are available for joining of thermoplastics, ultrasonic welding is one of the preferred processes. Thermoplastic polymers are categorized according to their molecular structure as amorphous and semi-crystalline. Ultrasonic welding of these

K. S. Suresh; M. Roopa Rani; K. Prakasan; R. Rudramoorthy

2007-01-01

318

Predicting the fatigue life of pristine and pre-corroded friction stir welded joints  

Microsoft Academic Search

Purpose – Friction stir welding (FSW) is simple, clean and cost effective joining technology which allows high-quality joining of materials that have been traditionally troublesome to weld conventionally without distortion, cracks or voids such as high-strength aluminium alloys. Since FSW has been identified as “key technology” for primary aerospace structures, the recent FAR regulations for damage tolerance and fatigue evaluations

T. Ghidini; C. Dalle Donne; U. Alfaro Mercado

2011-01-01

319

Effect of Thermal Cycle on the Formation of Intermetallic Compounds in Laser Welding of Aluminum-Steel Overlap Joints  

Microsoft Academic Search

The intermetallic compound (IMC) (or intermetallic phase layer) has a significant influence on the mechanical properties ofjoints between dissimilar metals obtained by thermal processes such as laser welding. Its formation is basically affected by thermal cycles in the joining or contact zone, where the IMC is formed. Within this study, the influence of the thermal cycle on the formation of

J. Fan; C. Thomy; F. Vollertsen

2011-01-01

320

Effects of TiO 2 coating on the microstructures and mechanical properties of tungsten inert gas welded AZ31 magnesium alloy joints  

Microsoft Academic Search

The effects of TiO2 coating on the macro-morphologies, microstructures and mechanical properties of tungsten inert gas (TIG) welded AZ31 magnesium alloy joints were investigated by microstructural observations, microhardness tests and tensile tests. The results showed that an increase in the amount of the TiO2 coating resulted in an increase in the weld penetration and the depth\\/width (D\\/W) ratio of the

Linzhi Wang; Jun Shen; Nan Xu

2011-01-01

321

Fatigue strength improvement of 5083 H11 Al-alloy T-welded joints by shot peening: experimental characterization and predictive approach  

Microsoft Academic Search

Shot peening improvement of high cycle fatigue (HCF) behavior of metal inert gas (MIG) welded T-joints made from 5083 H11 Al-alloy plates using 5183 Al-alloy welding wires was evaluated by means of four-point bending fatigue tests. The enhancement of the fatigue limits at 2×106 cycles were 135 and 59% for the stress ratios R1=0.1 and R2=0.5, respectively. The properties of

N. Sidhom; A. Laamouri; R. Fathallah; C. Braham; H. P. Lieurade

2005-01-01

322

Stress concentration factors and fatigue behaviour of welded thin-walled CHS–SHS T-joints under in-plane bending  

Microsoft Academic Search

Fatigue tests were carried out on welded thin-walled (t<4 mm) T-joints made of circular hollow section (CHS) braces welded onto square hollow section (SHS) chords, under the loading conditions of “in-plane bending in the brace”. Stress distributions were measured at different hot spot locations around the chord–brace junction, where cracks were observed to initiate and grow causing fatigue failure. The

Fidelis Rutendo Mashiri; Xiao-Ling Zhao; Paul Grundy

2004-01-01

323

Prediction and Optimization of Pulsed Current Gas Tungsten Arc Welding Process Parameters to Obtain Sound Weld Pool Geometry in Titanium Alloy Using Lexicographic Method  

Microsoft Academic Search

Abstact  In this article the weld pool geometry of pulsed current gas tungsten arc (GTA)-welded titanium alloy was analyzed. Increase\\u000a in use of pulsed current process creates dependancy on the use of mathematical equations to predict the weld pool geometry.\\u000a Hence, the development of mathematical models using four factors, five levels, central composite design was attempted. The\\u000a developed models were checked

M. Balasubramanian; V. Jayabalan; V. Balasubramanian

2009-01-01

324

Effects of CaF2 Coating on the Microstructures and Mechanical Properties of Tungsten Inert Gas Welded AZ31 Magnesium Alloy Joints  

NASA Astrophysics Data System (ADS)

The effects of CaF2 coating on the macromorphologies of the welded seams were studied by morphological analysis. Microstructures and mechanical properties of butt joints welded with different amounts of CaF2 coatings were investigated using optical microscopy and tensile tests. The welding defects formed in the welded seams and the fracture surfaces were analyzed by scanning electron microscopy. An increase in the amount of CaF2 coating deteriorated the appearances of the welded seams but it improved the weld penetration depth and the depth/width ( D/ W) ratio of the tungsten inert gas (TIG) welded joints. The ?-Mg grains and Mg17(Al,Zn)12 intermetallic compound (IMC) were coarser in the case of a higher amount of CaF2 coating. The increase in the amount of CaF2 coating reduced the porosities and total length of solidification cracks in the fusion zone (FZ). The ultimate tensile strength (UTS) value and elongation increased at first and then decreased sharply.

Shen, Jun; Wang, Linzhi; Peng, Dong; Wang, Dan

2012-11-01

325

Weld penetration and defect control. Final report  

SciTech Connect

Highly engineered designs increasingly require the use of improved materials and sophisticated manufacturing techniques. To obtain optimal performance from these engineered products, improved weld properties and joint reliability are a necessarily. This requirement for improved weld performance and reliability has led to the development of high-performance welding systems in which pre-programmed parameters are specified before any welding takes place. These automated systems however lack the ability to compensate for perturbations which arise during the welding process. Hence the need for systems which monitor and control the in-process status of the welding process. This report discusses work carried out on weld penetration indicators and the feasibility of using these indicators for on-line penetration control.

Chin, B.A.

1992-05-15

326

Polishing-assisted galvanic corrosion in the dissimilar friction stir welded joint of AZ31 magnesium alloy to 2024 aluminum alloy  

SciTech Connect

Galvanic corrosion of a dissimilar friction stir welded 2024-T3 Al/AZ31B-H24 Mg joint prepared using a water-based and a non-water-based polishing solution was characterized. Microstructure and the distribution of chemical elements were analyzed using optical microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. The stir zone polished using water-based solution was observed to be much more susceptible to galvanic corrosion attack than that obtained using non-water-based polishing solution. The location of corrosion attack was observed in the narrow regions of AZ31 Mg alloy adjacent to Al2024 regions in the stir zone. The occurrence of galvanic corrosion was due to the formation of Mg/Al galvanic couples with a small ratio of anode-to-cathode surface area. The corrosion product was primarily the porous magnesium hydroxide with characteristic microcracks and exhibited a low microhardness value.

Liu, C. [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada); Chen, D.L. [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada)], E-mail: dchen@ryerson.ca; Bhole, S. [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada); Cao, X.; Jahazi, M. [Aerospace Manufacturing Technology Centre, Institute For Aerospace Research, National Research Council Canada, 5145 Decelles Avenue, Montreal, Quebec H3T 2B2 (Canada)

2009-05-15

327

A Statistical Procedure for Re-Analysing Fatigue-Test-Results, Applied to Welded Joints in Al Zn Mg1, Al Zn4 Mg1 and Al Mg Si.  

National Technical Information Service (NTIS)

A new procedure for analyzing experimental fatigue results for welded joints was applied to several kinds of aluminum alloys. The same scatter-band computed in a previous work for welded joints in Al Mg5 was found to be valid for all the considered alumin...

B. Atzori A. Trentadue

1976-01-01

328

Optimizing friction stir welding parameters to maximize tensile strength of AA2219 aluminum alloy joints  

Microsoft Academic Search

AA2219 aluminium alloy (Al-Cu-Mn alloy) has gathered wide acceptance in the fabrication of lightweight structures requiring\\u000a a high strength-to-weight ratio and good corrosion resistance. In contrast to the fusion welding processes that are routinely\\u000a used for joining structural aluminium alloys, the friction stir welding (FSW) process is an emerging solid state joining process\\u000a in which the material that is being

S. Babu; K. Elangovan; V. Balasubramanian; M. Balasubramanian

2009-01-01

329

Properties of Friction Stir Welded Joints: A Review of the Literature  

Microsoft Academic Search

The solid-state process of friction stir welding (FSW) was invented in 1991 by TWI (1), and its emergence as a commercial joining technique is partly due to the ease with which the more difficult-to-weld high strength aluminium alloys can be joined. Whilst the process was developed initially for aluminium alloys, over the past decade the number of materials found to

D. Harris; A. F. Norman

330

Effect of 0.5 wt.% hydrogen addition on microstructural evolution of Ti–6Al–4V alloy in the friction stir welding and post-weld dehydrogenation process  

Microsoft Academic Search

The ?+? titanium alloy, Ti–6Al–4V, was thermohydrogen processed with 0.5wt.% hydrogen and friction stir welded using a W–Re pin tool. Defect-free joints were obtained with proper parameters. Hydrogen was removed from the joint through a post-weld dehydrogenation process. The microstructures of the as-welded and dehydrogenated joints were examined. The effect of 0.5wt.% hydrogen addition on microstructural evolution of Ti–6Al–4V alloy

L. Zhou; H. J. Liu

2011-01-01

331

Prediction and comparison of the area of the heat-affected zone for the bead-on-plate and bead-on-joint in submerged arc welding of pipes  

Microsoft Academic Search

The effect of controllable process variables on the heat input and the area of the heat-affected zone (HAZ) for bead-on-plate and bead-on-joint welding were calculated and analyzed using mathematical models developed for the submerged arc welding of pipes (SAW). A comparative study of the area of the heat-effected zone between bead-on-plate and bead-on-joint welding was carried out.This comparative study reveals

V Gunaraj; N Murugan

1999-01-01

332

Fatigue design of welded joints from the wrought magnesium alloy AZ31 by the local stress concept with the fictitious notch radii of r f = 1.0 and 0.05 mm  

Microsoft Academic Search

Investigations were carried out with three different types of MIG- and TIG-welded joints of the magnesium alloy AZ31(ISO-MgAl3Zn1): fully or partially penetrated butt welds, transversal stiffeners. The evaluation of the results showed that the local stress concept using the fictitious notch radius of rf=1.0 mm can be applied to magnesium welded joints from plates with thicknesses t?5 mm independently of

Ö. Karakas; C. Morgenstern; C. M. Sonsino

2008-01-01

333

Influences of pulsed current welding and post weld aging treatment on fatigue crack growth behaviour of AA7075 aluminium alloy joints  

Microsoft Academic Search

This paper reports the influences of pulsed current welding and post weld aging treatment on fatigue crack growth behaviour of AA7075 aluminium alloy (Al–Zn–Mg–Cu alloy). The preferred welding processes for this alloy are frequently gas tungsten arc welding (GTAW) process and gas metal arc welding (GMAW) process due to their comparatively easier applicability and better economy. In this alloy, the

V. Balasubramanian; V. Ravisankar; G. Madhusudhan Reddy

2008-01-01

334

Weld joint concepts for on-orbit repair of Space Station Freedom fluid system tube assemblies  

NASA Astrophysics Data System (ADS)

Because Space Station Freedom (SSF) is an independent satellite, not depending upon another spacecraft for power, attitude control, or thermal regulation, it has a variety of tubular, fluid-carrying assemblies on-board. The systems of interest in this analysis provide breathing air (oxygen and nitrogen), a working fluid (two-phase anhydrous ammonia) for thermal control, and a monopropellant (hydrazine) for station reboost. The tube assemblies run both internally and externally with respect to the habitats. They are found in up to 50 ft. continuous lengths constructed of mostly AISI 316L stainless steel tubing, but also including some Inconel 625 nickel-iron and Monel 400 nickel-copper alloy tubing. The outer diameters (OD) of the tubes range from 0.25-1.25 inches, and the wall thickness between 0.028-.095 inches. The system operational pressures range from 377 psi (for the thermal control system) to 3400 psi (for the high pressure oxygen and nitrogen supply lines in the ECLSS). SSF is designed for a fifteen to thirty year mission. It is likely that the tubular assemblies (TA's) will sustain damage or fail during this lifetime such that they require repair or replacement. The nature of the damage will be combinations of punctures, chips, scratches, and creases and may be cosmetic or actually leaking. The causes of these hypothetical problems are postulated to be: (1) faulty or fatigued fluid joints--both QD's and butt-welds; (2) micro-meteoroid impacts; (3) collison with another man-made object; and (4) over-pressure strain or burst (system origin). While the current NASA baseline may be to temporarily patch the lines by clamping metal c-sections over the defect, and then perform high pressure injection of a sealing compound, it is clear that permanent repair of the line(s) is necessary. This permanent repair could be to replace the entire TA in the segment, or perhaps the segment itself, both alternatives being extremely expensive and risky. The former would likely require extensive EVA to release TA clamps and pose great risk to other engineering subsystems, and the latter would require major de-servicing of the Station.

Jolly, Steven D.

1993-11-01

335

Electroslag Welding on Hydraulic Machinery.  

National Technical Information Service (NTIS)

The use of consumable guide electroslag welding process with components for hydraulic machinery having curved and profiled seams is described. Tests were carried out to optimize the welding parameters and the mechanical properties of welding joints with c...

E. Schorer F. J. Edel A. Borontschuk

1983-01-01

336

A Comparative Analysis of the Impact of Tool Design to Fatigue Behavior of Single-Sided and Double-Sided Welded Butt Joints of EN AW 6082-T6 Alloy  

NASA Astrophysics Data System (ADS)

In this paper, the results of fatigue behavior on friction stir welded joints of aluminum alloy EN AW 6082-T6 are reported. In particular, the study presents the influence of the geometry of a welding tool on fatigue strengths and tensile strengths. The test joints were prepared as single side welded and double side welded by FSW. The welding was performed at various linear welding speeds (224, 560, and 900 mm/min) and one rotational speed of 710 rev./min using three different tool shapes. The results of macro examination and tensile test led to the selection of a single set of tool movement parameters at which the test joints for fatigue test were made. Samples were tested in two states of surface condition, i.e., "as-welded" and with mechanically removed marks left by rotating and moving tool during FSW process. Studies have shown that fatigue behavior of FSW joints depends on the tool shape used in the welding process as well as the surface condition of welded joints and manner of joint production.

Krasnowski, K.; Dymek, S.

2013-09-01

337

Effect of Weld Penetration on the Stress Concentration Factor for Cruciform Welded Joints Effetto Della Mancanza di Penetrazi One Sulfattore di Effetto di Intaglio Per Giunti Saldati a Croce.  

National Technical Information Service (NTIS)

The influence of the lack of penetration on the elastic stress concentration factor of a cruciform welded joint loaded by axial of bending forces was investigated k sub t. The analysis was performed using finite element techniques with an isoparametric qu...

B. Atzori C. Pappalettere

1978-01-01

338

Experimental and calculated evaluation of the supporting capacity of steel 13KhGMF welded joints in the low endurance region  

SciTech Connect

In recent years thermally-hardened low-alloy steel 13KhGMF, which exhibits high mechanical properties and good weldability, has found use in hydrotechnical structures. In this work, besides studying static and cyclic properties of individual zones of butt joints in steel 13KhGMF, consideration is given to regularities of deformation and failure for welded joints made by the methods indicated with measurement of the geometric parameters of the joints, and a calculated evaluation is also given for their supporting capacity in the region of loading cycles not exceeding 10/sup 5/. The results show that the mechanical properties of the different zones of joints made by manual and electroslag welding differ markedly. The metal resistance of different joints to low-cycle failure is presented. A comparison is shown of experimental and calculated curves for the development of a fatigue crack in welded joints of steel 13KhGMF. The effect of nonuniformity in mechanical properties on the supporting capacity of joints in steel 13KhGMF is shown to be most marked in the quasistatic failure region.

Yakubovskii, V.V.

1987-03-01

339

Macro\\/micro mechanical level characterization of friction stir welded joints in aluminum alloys using combined experimental\\/numerical approaches  

Microsoft Academic Search

Friction stir welding (FSW) is a solid state joining process having key benefits such as low energy consumption, greater environmental friendliness and increased versatility, when compared with the conventional welding processes such as gas metal arc welding or tungsten inert-gas welding. The FSW process has been used successfully to weld high strength aluminum alloys that are used in the aerospace

Srinivasa Deshikan Thoppul

2008-01-01

340

Study on the preciseness of hot spot stress of web-stiffened cruciform welded joints derived from shell finite element analyses  

Microsoft Academic Search

A new simple and accurate shell FE-based structural Hot Spot Stress (HSS) determination method for web-stiffened cruciform joints has been proposed. Local stress of welded joints in full-scale bulk carrier (BC)’s lower stool models subject to bending and pressure loadings are examined. HSSs determined by the proposed method are compared with those derived by Lotsberg’s method and the conventional 0.5t–1.5t

N. Osawa; N. Yamamoto; T. Fukuoka; J. Sawamura; H. Nagai; S. Maeda

2011-01-01

341

Effect of Mean Stress on Fatigue-Crack Growth in Cruciform-Welded Joints Under Non-Stationary Narrow-Band Random Loading.  

National Technical Information Service (NTIS)

Some fatigue tests were carried out in room temperature air at zero and high mean-stress on unstress-relieved cruciform-welded steel joints. The load history used consisted of four different levels of stationary narrow-band random loading arranged in risi...

L. P. Pook

1983-01-01

342

Automated evaluation of the quality of butt welded joint in magnetographic flaw inspection. II. Examination of the operation efficiency of an algorithm for suppressing the bead signal  

SciTech Connect

A model of a surface dipole is used to examine by numerical modeling the efficiency of the algorithm of suppressing signal of the bead of a butt welded joint in magnetographic flaw inspection. The results show that the defects can be automatically evaluated on the basis of the characteristics of the resultant signal.

Mikhailov, S.P.; Scherbinin, V.E.

1994-12-01

343

Tensile Properties of LE-7 Engine Material with Welded Joints. 3rd Report. Influence of Solution Treatment Conditions upon Micro Structures and Tensile Properties.  

National Technical Information Service (NTIS)

The authors studied the tensile properties of the GTA welded joint with solution treated at 1228 K and 1338 K in a previous report. This report shows the effects of solution treatment condition (time and temperature) ranging from 1228 K to 1338 K on the m...

M. Yoshida T. Hashimoto Y. Watanabe

1996-01-01

344

Fatigue Resistance of Welded Joints in Almg5 Subjected to Bending Resistenza a Fatica di Giunti Saldati in Almg5 Sollecitati a Flessione.  

National Technical Information Service (NTIS)

The bending behavior of several types of welded joints was investigated in order to determine their fatigue resistance characteristics. The materials examined were alloys of aluminum and magnesium with percentages of Mg between 3 and 5.5. A comparison was...

B. Atzori

1976-01-01

345

Micromechanism of failure in off-centre tensile loading of fusion welded joints in 1422 high-strength aluminium–lithium alloy  

Microsoft Academic Search

The results of the investigation of the micromechanisms of failure and special features of the morphology of fracture of various sections of fusion welded joints in 1422 aluminium–lithium alloy in relation to the position of the stress concentrator with respect to applied load in off-centre tensile loading are presented.

T. M. Labur; A. Ya. Ishchenko; T. G. Taranova; G. M. Grigorenko; V. A. Kostin; A. A. Chaika

2011-01-01

346

Micromechanism of failure in off-centre tensile loading of fusion welded joints in 1422 high-strength aluminium–lithium alloy  

Microsoft Academic Search

The results of the investigation of the micromechanisms of failure and special features of the morphology of fracture of various sections of fusion welded joints in 1422 aluminium–lithium alloy in relation to the position of the stress concentrator with respect to applied load in off-centre tensile loading are presented.

T. M. Labur; A. Ya. Ishchenko; T. G. Taranova; G. M. Grigorenko; V. A. Kostin; A. A. Chaika

2012-01-01

347

Analysis of residual stress in stainless steel pipe weld subject to mechanical axial tension loading  

Microsoft Academic Search

This paper presents the characteristics of welding residual stresses in circumferentially butt-welded stainless steel pipe\\u000a by utilizing three-dimensional (3-D) uncoupled thermo-mechanical finite element (FE) analysis method. Moreover, stress variations\\u000a in welded joints of the pipe under superimposed mechanical axial tension loading are further investigated employing the welding\\u000a residual stresses and plastic strains obtained from the thermo-mechanical FE analysis as an

Kyong-Ho Chang; Chin-Hyung Lee; Ki-Tae Park; Young-Jun You; Bong-Chul Joo; Gab-Chul Jang

2010-01-01

348

Laser welding of NiTi shape memory alloy: Comparison of the similar and dissimilar joints to AISI 304 stainless steel  

NASA Astrophysics Data System (ADS)

The unique properties of NiTi alloy, such as its shape memory effect, super-elasticity and biocompatibility, make it ideal material for various applications such as aerospace, micro-electronics and medical device. In order to meet the requirement of increasing applications, great attention has been given to joining of this material to itself and to other materials during past few years. Laser welding has been known as a suitable joining technique for NiTi shape memory alloy. Hence, in this work, a comparative study on laser welding of NiTi wire to itself and to AISI 304 austenitic stainless steel wire has been made. Microstructures, mechanical properties and fracture morphologies of the laser joints were investigated using optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction analysis (XRD), Vickers microhardness (HV0.2) and tensile testing techniques. The results showed that the NiTi-NiTi laser joint reached about 63% of the ultimate tensile strength of the as-received NiTi wire (i.e. 835 MPa) with rupture strain of about 16%. This joint also enabled the possibility to benefit from the pseudo-elastic properties of the NiTi component. However, tensile strength and ductility decreased significantly after dissimilar laser welding of NiTi to stainless steel due to the formation of brittle intermetallic compounds in the weld zone during laser welding. Therefore, a suitable modification process is required for improvement of the joint properties of the dissimilar welded wires.

Mirshekari, G. R.; Saatchi, A.; Kermanpur, A.; Sadrnezhaad, S. K.

2013-12-01

349

Model of Process and Calculation of Energy for a Heat Generation of a Welded Joint at Ultrasonic Welding Polymeric Thermoplastic Materials  

Microsoft Academic Search

In article results calculation of energy the ultrasonic vibrations disseminated in a welding zone of thermoplastic materials in view of reflecting and passing properties of borders welded materials, support and the working tool of oscillatory system are presented. Dependence of time necessary for bonding of materials, in view of properties, thickness, amplitude, frequency of ultrasonic welding is certain. The found

Vladimir N. Khmelev; Alexey N. Slivin; Alexey D. Abramov

2007-01-01

350

Fatigue of Iron Base Alloys HY-80 Steel Cast Tees Butt Welded to Rolled Section Single and Double Weld Joint Design.  

National Technical Information Service (NTIS)

The average fatigue life of 1 5/8 in. thick cast tee butt welded to rolled plate is approximately the same as that of cast plate butt welded to rolled plate and rolled plate butt welded to rolled plate. At 80,000 psi nominal stress range the fatigue life ...

1964-01-01

351

FATIGUE ANALYSIS METHODS: THEIR PERFORMANCE EVALUATION FOR A CLASS OF PRESSURE VESSELS WITH WELDED JOINTS  

Microsoft Academic Search

This paper provides a basis for evaluating the performance of a fatigue analysis method for a selected class of welded pressure vessels. After the allowable number of cycles that the method permits for a member of the class is calculated, the question is addressed whether that number of cycles can be regarded as conservative or unconservative. To answer that question,

Arturs Kalnins

2009-01-01

352

Low Cycle Fatigue (LCF) of Solar Cell Welding Joints Made of Silver.  

National Technical Information Service (NTIS)

To improve solar cell modules for low Earth orbit missions of greater than 10 yr, low cycle fatigue investigations on silver interconnectors welded on silverized silicon solar cells were conducted. Experiments on 20 and 35 micron thick Ag-foil interconnec...

S. Reul

1986-01-01

353

Microstructure and hardness of friction stir welded 7075 aluminium alloy joints  

Microsoft Academic Search

Friction stir welding (FSW) is a process which induces a reduction in flow stress owing to friction heat generated by pressing a protruded object into a solid material and rotating it at high speed. It induces part of the material to have plastic flow owing to friction force in order to join materials together. The FSW method was developed for

T. Shibayanagi; M. Maeda

2005-01-01

354

Dual wire welding torch and method  

DOEpatents

A welding torch includes a nozzle with a first welding wire guide configured to orient a first welding wire in a first welding wire orientation, and a second welding wire guide configured to orient a second welding wire in a second welding wire orientation that is non-coplanar and divergent with respect to the first welding wire orientation. A method of welding includes moving a welding torch with respect to a workpiece joint to be welded. During moving the welding torch, a first welding wire is fed through a first welding wire guide defining a first welding wire orientation and a second welding wire is fed through a second welding wire guide defining a second welding wire orientation that is divergent and non-coplanar with respect to the first welding wire orientation.

Diez, Fernando Martinez (Peoria, IL); Stump, Kevin S. (Sherman, IL); Ludewig, Howard W. (Groveland, IL); Kilty, Alan L. (Peoria, IL); Robinson, Matthew M. (Peoria, IL); Egland, Keith M. (Peoria, IL)

2009-04-28

355

Heat and fluid flow in complex joints during gas metal arc welding-Part II: Application to fillet welding of mild steel  

NASA Astrophysics Data System (ADS)

A numerical model described in part I [W. Zhang, C.-H. Kim, and T. DebRoy, J. Appl. Phys. 95, 5210 (2004)] was used to investigate the heat transfer and free surface flow during gas metal arc fillet welding of mild steel. Dimensional analysis was used to understand the importance of heat transfer by conduction and convection and the role of various driving forces on convection in the liquid weld pool. The calculated shape and size, finger penetration characteristic and solidified surface profile of the fillet welds were in fair agreement with the experimental results for various welding conditions. The calculated cooling rates were also in good agreement with independent experimental data. The effect of welding parameters on important weld bead characteristics was quantitatively studied using the numerical model. The results reported here indicate a significant promise for understanding and control of gas metal arc fillet welding processes based on fundamental principles of transport phenomena.

Zhang, W.; Kim, C.-H.; Debroy, T.

2004-05-01

356

Improving fatigue performance of rail thermite welds  

NASA Astrophysics Data System (ADS)

Rail transport development offers economic and ecological interests. Nevertheless, it requires heavy investments in rolling material and infrastructure. To be competitive, this transportation means must rely on safe and reliable infrastructure, which requires optimization of all implemented techniques and structure. Rail thermite (or aluminothermic) welding is widely used within the railway industry for in-track welding during re-rail and defect replacement. The process provides numerous advantages against other welding technology commonly used. Obviously, future demands on train traffic are heavier axle loads, higher train speeds and increased traffic density. Thus, a new enhanced weld should be developed to prevent accidents due to fracture of welds and to lower maintenance costs. In order to improve such assembly process, a detailed metallurgical study coupled to a thermomechanical modelling of the phenomena involved in the thermite welding process is carried out. Obtained data enables us to develop a new improved thermite weld (type A). This joint is made by modifying the routinely specified procedure (type B) used in a railway rail by a standard gap alumino-thermic weld. Joints of type A and B are tested and compared. Based on experimental temperature measurements, a finite element analysis is used to calculate the thermal residual stresses induced. In the vicinity of the weld, the residual stress patterns depend on the thermal conditions during welding as it also shown by litterature [1, 2]. In parallel, X-Ray diffraction has been used to map the residual stress field that is generated in welded rail of types A and B. Their effect on fatigue crack growth in rail welds is studied. An experimental study based on fatigue tests of rails welded by conventional and improved processes adjudicates on the new advances and results will be shown.

Jezzini-Aouad, M.; Flahaut, P.; Hariri, S.; Winiar, L.

2010-06-01

357

Wind load resistance tests of heat-welded joints between roofing felt and sheet metal flashings  

Microsoft Academic Search

The wind load resistance of joints between roofing felt and sheet metal has been measured in a wind uplift chamber. Both bituminous and polymeric roofing felts have been used. The sheet metal has been PVC-coated galvanised steel sheets and the bituminous roofing felts have been of both SBS and APP modified type. All the joints have been made by heat

Fredrik Gränne; Folke Björk; Knut Noreng

2003-01-01

358

Fatigue crack initiation life prediction in high strength structural steel welded joints  

NASA Astrophysics Data System (ADS)

The local approach method is used to calculate the fatigue crack initiation/early crack growth lives (N(i)) in high strength structural steel weldments. Weld-toe geometries, welding residual stresses and HAZ (heat affected zone) cyclic mechanical properties are taken into account in the N(i) estimation procedure. Fatigue crack initiation lives are calculated from either a Basquin type or a Manson-Coffin type equation. The local (HAZ) stress and strain amplitudes and the local mean stress are determined from an analysis based on the Neuber rule and the Molski-Glinka energy approach. The accuracy of the different methods is evaluated and discussed. Finally the previous methods are used with HAZ cyclic mechanical properties estimated from hardness measurements.

Tricoteaux, A.; Fardoun, F.; Degallaix, S.; Sauvage, F.

1995-02-01

359

Fatigue behaviour of T welded joints rehabilitated by tungsten inert gas and plasma dressing  

Microsoft Academic Search

This paper concerns a fatigue study on the effect of tungsten inert gas (TIG) and plasma dressing in non-load-carrying fillet welds of structural steel with medium strength. The fatigue tests were performed in three point bending at the main plate under constant amplitude loading, with a stress ratio of R=0.05 and a frequency of 7Hz.Fatigue results are presented in the

Armando L. Ramalho; José A. M. Ferreira; Carlos A. G. M. Branco

2011-01-01

360

The use of the J V parameter in welded joints: Stress analysis and fatigue assessment  

Microsoft Academic Search

This paper investigates the use of the JV parameter, a path-independent integral, for the evaluation of the elastic local stress parameters in welded details and for the estimation of their fatigue life.First, the stress intensity factors (SIF) of an embedded crack lying along the bisector of a sharp V-notch is calculated by means of the JV without modelling the crack

Paolo Livieri; Roberto Tovo

2009-01-01

361

Visualization of local electrochemical activity and local nickel ion release on laser-welded NiTi/steel joints using combined alternating current mode and stripping mode SECM.  

PubMed

Smoothly polished cross-sections of laser-fabricated welds between NiTi shape memory alloy and stainless steel (SS) microwires of approximately the same diameter and, for comparison, between identical stainless steel or NiTi wires have been subjected to local chemical activity and nickel release measurements using scanning electrochemical microscopy (SECM). In the alternating current mode (AC-SECM), the measurements detected clear differences in the local interfacial chemical activity of the passivated weld and the base metals only for the heterogeneous joints of the type NiTi-SS. In this case the local electrochemical acvtivity was lower above the weld material. Subjecting cross-sections of NiTi-SS to stripping mode SECM (SM-SECM), higher Ni(2+) concentrations were measured above the regions of the parental NiTi wire, which correlates well with the results from AC-SECM imaging which showed this region as being less passivated. An energy-dispersive elemental analysis of the specimen in a scanning electron microscope revealed the coexistence of Ti and Cr in the weld mass. Possibly, a joint action of these two metals in terms of protective oxide formation is better for passivation of the weld region than the individual action of one or the other element for passivating the original wires. Better passivation of course led to decreased electrochemical activity of the weld surface. Apparently, AC- and SM-mode SECM imaging were sufficiently sensitive to detect and visualize the impact of the changed surface passivation upon laser welding. PMID:19082072

Ruhlig, D; Gugel, H; Schulte, A; Theisen, W; Schuhmann, W

2008-09-23

362

Quantitative ultrasonic testing of acoustically anisotropic materials with verification on austenitic and dissimilar weld joints  

NASA Astrophysics Data System (ADS)

Austenitic stainless steel materials are widely used in a variety of industry sectors. In particular, the material is qualified to meet the design criteria of high quality in safety related applications. For example, the primary loop of the most of the nuclear power plants in the world, due to high durability and corrosion resistance, is made of this material. Certain operating conditions may cause a range of changes in the integrity of the component, and therefore require nondestructive testing at reasonable intervals. These in-service inspections are often performed using ultrasonic techniques, in particular when cracking is of specific concern. However, the coarse, dendritic grain structure of the weld material, formed during the welding process, is extreme and unpredictably anisotropic. Such structure is no longer direction-independent to the ultrasonic wave propagation; therefore, the ultrasonic beam deflects and redirects and the wave front becomes distorted. Thus, the use of conventional ultrasonic testing techniques using fixed beam angles is very limited and the application of ultrasonic Phased Array techniques becomes desirable. The "Sampling Phased Array" technique, invented and developed by Fraunhofer IZFP, allows the acquisition of time signals (A-scans) for each individual transducer element of the array along with fast image reconstruction techniques based on synthetic focusing algorithms. The reconstruction considers the sound propagation from each image pixel to the individual sensor element. For anisotropic media, where the sound beam is deflected and the sound path is not known a-priori, a novel phase adjustment technique called "Reverse Phase Matching" is implemented. By taking into account the anisotropy and inhomogeneity of the weld structure, a ray tracing algorithm for modeling the acoustic wave propagation and calculating the sound propagation time is applied. This technique can be utilized for 2D and 3D real time image reconstruction. The "Gradient Constant Descent Method" (GECDM), an iterative algorithm, is implemented, which is essential for examination of inhomogeneous anisotropic media having unknown properties (elastic constants). The Sampling Phased Array technique with Reverse Phase Matching extended by GECDM-technique determines unknown elastic constants and provides reliable and efficient quantitative flaw detection in the austenitic welds. The validation of ray-tracing algorithm and GECDM-method is performed by number of experiments on test specimens with artificial as well as natural material flaws. A mechanized system for ultrasonic testing of stainless steel and dissimilar welds is developed. The system works on both conventional and Sampling Phased Array techniques. The new frontend ultrasonic unit with optical data link allows the 3D visualization of the inspection results in real time.

Boller, C.; Pudovikov, S.; Bulavinov, A.

2012-05-01

363

Influence of welding consumables on high cycle fatigue life of flux cored Arc welded high strength, quenched and tempered steel joints  

Microsoft Academic Search

Quenched and tempered (Q&T) steels are prone to hydrogen induced cracking after welding. Austenitic stainless steel (ASS)\\u000a welding consumables are traditionally used for welding of high hardness, Q&T steels as they have higher solubility for hydrogen\\u000a in the austenitic phase. The use of stainless steel consumables for a non stainless steel base metal is not economical. Hence,\\u000a in the present

Govindaraj Magudeeswaran; Visvalingam Balasubramanian; Gankidi Madhusudhan Reddy

2008-01-01

364

Effect of alloying armco iron on the properties of composite joints  

Microsoft Academic Search

In order to obtain high-quality welded joints between aluminum and its alloys and various types of steel, we resort to the preliminary coating of the steel with zinc, aluminum, or other metal. Ryabov [1] has shown how the various forms of zinc coating affect the properties and thickness of the diffusion zone which determines the strength of the welded joints.

V. R. Ryabov; V. I. Yumatova; A. P. Butnik

1973-01-01

365

The effect of upsetting conditions on flash weld toughness. Study on toughness improvement of flash welded joints in high strength steel  

Microsoft Academic Search

An investigation was carried out of the factors influencing the toughness of flash welded high strength steel plate. It was explained that the major factors for toughness degradation can be summarised by the following: there is an inclusion factor, that is oxides which remain at the weld interface and act as the starting point for fracture and the inclusions within

Y. Ichiyama; M. Ichikawa; T. Saito

2004-01-01

366

Local mechanical properties of Alloy 82/182 dissimilar weld joint between SA508 Gr.1a and F316 SS at RT and 320C  

SciTech Connect

This paper presents the variations of local mechanical and microstructural properties in dissimilar metal weld joints consisting of the SA508 Gr.1a ferritic steel, Alloy 82/182 filler metal, and F316 austenitic stainless steel. Flat or round tensile specimens and transmission electron microscopy disks were taken from the base metals, welds, and heat-affected zones (HAZ) of the joints and tested at room temperature (RT) and/or at 320 C. The tensile test results indicated that the mechanical property was relatively uniform within each material zone, but varied considerably between different zones. Further, significant variations were observed both in the austenitic HAZ of F316 SS and in the ferritic HAZ of SA508 Gr.1a. The yield stress (YS) of the weld metal was under-matched with respect to the HAZs of SA508 Gr.1a and F316 SS by 0.78 to 0.92, although the YS was over-matched with respect to both base metals. The minimum ductility occurred in the HAZ of SA508 Gr.1 at both test temperatures. The plastic instability stress also varied considerably in the weld joints, with minimum values occurring in the SA508 Gr.1a base metal at RT and in the HAZ of F316 SS at 320 C, suggesting that the probability of ductile failure caused by a unstable deformation at the Alloy 82/182 buttering layer is low. Within the HAZ of SA508 Gr.1a, the gradient of the YS and ultimate tensile strength (UTS) was significant, primarily because of the different microstructures produced by the phase transformation during the welding process. The increment of YS was unexpectedly high in the HAZ of F316 SS, which was explained by the strain hardening induced by a strain mismatch between the weldment and the base metal. This was confirmed by the transmission electron micrographs showing high dislocation density in the HAZ.

Byun, Thak Sang [ORNL; Kim, Jin Weon [ORNL

2009-01-01

367

Efficient weld seam detection for robotic welding based on local image processing  

Microsoft Academic Search

Purpose – The weld seam detection is required for a welding robot to preplan the weld seam track before the actual welding. The purpose of this paper is to investigate this subject in natural lighting conditions. Design\\/methodology\\/approach – This paper presents an efficient algorithm of weld seam detection for butt joint welding from a single image. The basic idea of

Fanhuai Shi; Tao Lin; Shanben Chen

2009-01-01

368

Regression modeling to predict the geometrical features of Ti6Al4V thin sheets butt joints welded by disk laser  

NASA Astrophysics Data System (ADS)

The aim of this work is to investigate the effects of power, welding speed, defocusing on geometric features and on defects of 1 mm Ti6Al4V laser welded butt joints by a new generation disk laser with 2 kW of maximum power. Them active gain is a Yb:YAG disk instead of traditional Nd:YAG rods. Disk geometry allows to keep the nominal beam quality also at high power because there is no thermal lensing effect, typical of rod geometry. A three level Box-Behnken experimental design with three repetitions is carried out for a total of 45 tests. Linear and quadratic regression equations are developed to relate the input factors to the output variables in order to predict the geometric features of butt joints.

Caiazzo, Fabrizia; Mastrocinque, Ernesto; Corrado, Gaetano; Sergi, Vincenzo

2012-05-01

369

Residual Stress Estimation of Welded Tubular K-joints under Fatigue Loads  

Microsoft Academic Search

In tubular joints, the hot spot stress concept is used to characterize the stress field at potential fatigue crack locations. The combination of determining stresses using the hot spot concept, with a reduction factor on fatigue strength is however not a satisfactory solution. In this paper, an overview of a on-going research project in which the overall phenomenon, including geometrical

C. Acevedo; A. Nussbaumer

370

Effect of a post-weld heat treatment on the mechanical and microstructure properties of AA6061 joints welded by the gas metal arc welding cold metal transfer method  

Microsoft Academic Search

This work studies the effect of a post-weld heat treatment (PWHT) on the mechanical and microstructure properties of an AA6061 sample welded using the gas metal arc welding (GMAW) cold metal transfer (CMT) method. The CMT method was used because the method provides spatter-free welding, outstanding gap bridging properties, low heat input and a high degree of process flexibility. The

R. Ahmad; M. A. Bakar

2011-01-01

371

Microstructure of the interface in magnesium alloy to aluminium alloy dissimilar joints produced by friction stir welding  

Microsoft Academic Search

Friction stir welding (FSW) is a process that was developed by the UK Welding Institute (TWI) in 1991. Because of its status as a solid-phase joining process operating at a temperature below the melting point of the materials being joined, FSW usually generates less residual stress than fusion welding, being also advantageously free from fume, porosity, and solidification cracking. The

S. Hirano; K. Okamoto; M. Doi; O. Kamura; M. Inagaki; Y. Aono

2004-01-01

372

Comparison of RSM with ANN in predicting tensile strength of friction stir welded AA7039 aluminium alloy joints  

Microsoft Academic Search

Friction stir welding(FSW) is an innovative solid state joining technique and has been employed in aerospace, rail, automotive and marine industries for joining aluminium, magnesium, zinc and copper alloys. The FSW process parameters such as tool rotational speed, welding speed, axial force, play a major role in deciding the weld quality. Two methods, response surface methodology and artificial neural network

A. K. LAKSHMINARAYANAN; V. BALASUBRAMANIAN

2009-01-01

373

Effect of cast-to-cast variations on the quality of thin section nickel alloy welded joints.  

National Technical Information Service (NTIS)

The welding behaviour of 26 commercial casts of Alloy 800 has been quantified for mechanised, autogenous, full penetration, bead-on-strip tungsten inert gas welding tests. Weld front and back widths have been measured and correlated with minor element var...

J. A. Lambert

1989-01-01

374

Joints  

NSDL National Science Digital Library

Hinge joints move only in one direction, ball-and-socket joints are free to rotate in all directions, and gliding joints are able to move forward, backward, and side to side, but do not rotate freely.

Olivia Worland (Purdue University;Biological Sciences)

2008-06-06

375

Materials Science Aspects of Weld Corrosion.  

National Technical Information Service (NTIS)

Corrosion is an environmentally assisted damage that professionals face daily, particularly with welded structures. Fusion welds result from solidification and solid-state transformations induced by well-localized thermal cycles. A fusion weld joint inher...

D. L. Olson A. N. Lasseigne M. Marya B. Mishra G. Castro

2003-01-01

376

Double-Sided Single-Pass Submerged Arc Welding for 2205 Duplex Stainless Steel  

NASA Astrophysics Data System (ADS)

The duplex stainless steel (DSS), which combines the characteristics of ferritic steel and austenitic steel, is used widely. The submerged arc welding (SAW) method is usually applied to join thick plates of DSS. However, an effective welding procedure is needed in order to obtain ideal DSS welds with an appropriate proportion of ferrite (?) and austenite (?) in the weld zone, particularly in the melted zone and heat-affected zone. This study evaluated the effectiveness of a high efficiency double-sided single-pass (DSSP) SAW joining method for thick DSS plates. The effectiveness of the converse welding procedure, characterizations of weld zone, and mechanical properties of welded joint are analyzed. The results show an increasing appearance and continuous distribution feature of the ? phase in the fusion zone of the leading welded seam. The converse welding procedure promotes the ? phase to precipitate in the fusion zone of leading welded side. The microhardness appears to significantly increase in the center of leading welded side. Ductile fracture mode is observed in the weld zone. A mixture fracture feature appears with a shear lip and tears in the fusion zone near the fusion line. The ductility, plasticity, and microhardness of the joints have a significant relationship with ? phase and heat treatment effect influenced by the converse welding step. An available heat input controlling technology of the DSSP formation method is discussed for SAW of thick DSS plates.

Luo, Jian; Yuan, Yi; Wang, Xiaoming; Yao, Zongxiang

2013-09-01

377

Modelling of fatigue crack growth in flat plate weldments and tubular welded joints  

NASA Astrophysics Data System (ADS)

Modeling of fatigue crack growth in T-butt plate weldments and tubular joints is discussed. Some of the available stress infinity factor solutions based on the finite element method and the weight function approach are analyzed. It is shown that simultaneous modeling of the fatigue growth of several multiple cracks provides a better simulation of crack shape development than do single crack models; single crack models may be unconservative. The results show that in the case of tubular joints it was necessary to supplement the methodology developed for plate weldments by an additional effect called 'load shedding'. It is believed that the load shedding effect arises due to varying boundary conditions caused by the growing crack.

Glinka, Grzegorz; Lambert, S.

1992-07-01

378

Monitoring of Welds by Acoustic Emission. Bibliographical Study of Results Obtained During Multipass Submerged Arc Welding Controle du Soudage Par Emission Acoustique. Etude Bibliographique des Resultats Obtenus Lors du Soudage Multipasses Sous Arc Submerge.  

National Technical Information Service (NTIS)

Different methods of solid flux welding are reviewed and the possibility of monitoring weld quality by acoustic emission is discussed. Phenomena which account for acoustic emission during welding are identified. Characterization of acoustic emission with ...

M. Nogues

1982-01-01

379

Development of Laser Welding of Ni based Superalloys for Aeronautic Engine Applications (Experimental Process and Obtained Properties)  

Microsoft Academic Search

Superalloys are designed for service at temperatures above 540°C. Due to their properties at high temperatures, this family of materials is used in different aircraft engine components. Aeronautic components demand reliable joining technologies. The laser welding of three different superalloys have been performed and analysed. Due to reduced extension of the heat affected zone (HAZ), and high quality and ratio

Fidel Zapirain; Fidel Zubiri; Fermín Garciandía; Itziar Tolosa; Samuel Chueca; Aimar Goiria

2011-01-01

380

A Study of the Effect of Tool Pin Profiles on Tensile Strength of Welded Joints Produced Using Friction Stir Welding Process  

Microsoft Academic Search

Friction Stir Welding (FSW) has evolved into a process focused on joining of arc-weldable (5xxx and 6xxx) and which are difficult to weld (2xxx and 7xxx) aluminium alloys. The method described in this paper for the prediction of tensile properties and optimization can eliminate the need for performing experiments on the basis of conventional trial and error method. The present

C. N. Suresha; B. M. Rajaprakash; Sarala Upadhya

2011-01-01

381

Joint sampling programme--verification of data obtained in environmental monitoring.  

PubMed

The objective of the Environmental Radiological Monitoring Control programme carried out by the Institute of Radiation Protection and Dosimetry (IRD) in Brazil is to verify the licensee's compliance with the requirements for environmental monitoring of Brazilian facilities. The Joint Sampling Programme (JSP) is just one part of the control programme. In order to verify that the data reported by the licensees is representative and legitimate, this programme verifies sampling procedures, accuracy and precision of the data and the changes in the environmental conditions. This paper discusses the main findings of this programme that allowed IRD to optimize its available resources to control the monitoring of the eight facilities in Brazil. PMID:18502139

Lauria, D C; Martins, N S F; Vasconcellos, M L H; Zenaro, R; Peres, S S; Pires do Rio, M A

2008-04-11

382

Study of friction stir welding of 01420 aluminum–lithium alloy  

Microsoft Academic Search

The 01420 Al–Li alloy plates were friction stir welded at different welding parameters. The effect of welding parameters on the quality of the 01420 Al–Li friction stir welded joints was investigated. As a result, the optimized combinations of various welding parameters (pin rotation speed, welding speed and welding pressure) were identified. By comparison of the heat inputs during welding process

Shitong Wei; Chuanyong Hao; Jichun Chen

2007-01-01

383

Virtual restoration of anatomic jaw relationship to obtain a precise 3D model for total joint prosthesis construction for treatment of TMJ ankylosis with open bite  

Microsoft Academic Search

Temporomandibular joint (TMJ) reconstruction with a TMJ Concepts total joint prosthesis (TMJ Concepts, Ventura, USA) requires a precise 3D model of the jaws in centric occlusion. The authors present a virtual procedure for repositioning the lower jaw in centric occlusion to obtain a precise stereolithographic model for TMJ reconstruction using a custom-made total joint prosthesis in a case of TMJ

C. Zizelmann; P. Bucher; D. Rohner; N.-C. Gellrich; H. Kokemueller; B. Hammer

2010-01-01

384

Optimal welding of beta titanium orthodontic wires.  

PubMed

Today the orthodontist is confronted by an array of new orthodontic wire materials that, when applied to appliance design, can vastly increase the flexibility and versatility of therapy. Welded joints, especially for the newer titanium alloy wires, provide a means to extend the useful applications of these materials. The purpose of this study was to determine the optimum settings for electrical resistance welding of various configurations of titanium-molybdenum (TMA) wires. Specimens were of a t-joint configuration and were mechanically tested in torsion to simulate the failure mode most often observed in clinical practice. Variables included wire size, wire orientation, and welding voltage. Results indicated that excellent welds can be obtained with very little loss of strength and ductility in the area of the weld joint. Torsional loads at failure were at least 90% of the unwelded base material. Although a wide range of voltage settings resulted in high-strength welds, typically a narrow range of voltages yielded optimal ductility. PMID:2888304

Nelson, K R; Burstone, C J; Goldberg, A J

1987-09-01

385

COMPORTAMENTO A FATICA DI GIUNTI A T FRICTION STIR WELDED IN LEGA DI ALLUMINIO  

Microsoft Academic Search

One of the most innovative joining processes is the friction stir welding (FSW). FSW is obtained without using any external heat supplier since the temperature is generated by a proper tool that rota tes and move along the welding centreline. The main interest in literature is focused on the f atigue strength of FSW butt joints. However this process is

L. Fratini; S. Pasta

386

An application of the implicit gradient method to welded structures under multiaxial fatigue loadings  

Microsoft Academic Search

This paper deals with the problem of fatigue strength assessment of welded joints subjected to multiaxial loading. Three-dimensional solid modelling and linear elastic stress analysis, by means of numerical methods, are used to investigate the local stress field at weld toes and roots, geometrically regarded as sharp notches. Starting from the stress field obtained from a linear elastic analysis and

A. Cristofori; P. Livieri; R. Tovo

2009-01-01

387

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

388

Thermomechanical treatments of Sc and Mg-modified Al–Cu alloy welds  

Microsoft Academic Search

High-strength heat-treatable aluminum alloy AA2219 finds application in aerospace industries. Though it has good weldability,\\u000a with alternating current–tungsten inert gas welding, the joint efficiency obtained is only 40%, particularly in thicker plates.\\u000a In the present study, an attempt has been made to improve the weld metal properties by modifying the chemistry of fusion zone\\u000a and post-weld thermo-mechanical treatments. Fillers were

S. R. Koteswara Rao; B. Kamsala Devi; K. Sreenivasa Rao; K. Prasad Rao

2009-01-01

389

Design of the friction stir welding tool using the continuum based FEM model  

Microsoft Academic Search

In friction stir welding (FSW), the welding tool geometry plays a fundamental role in obtaining desirable microstructures in the weld and the heat-affected zones, and consequently improving strength and fatigue resistance of the joint. In this paper, a FSW process with varying pin geometries (cylindrical and conical) and advancing speeds is numerically modeled, and a thermo-mechanically coupled, rigid-viscoplastic, fully 3D

G. Buffa; J. Hua; R. Shivpuri; L. Fratini

2006-01-01

390

Effect of Welding Processes and Consumables on Tensile and Impact Properties of High Strength Quenched and Tempered Steel Joints  

Microsoft Academic Search

Quenched and tempered steels are prone to hydrogen induced cracking in the heat affected zone after welding. The use of austenitic stainless steel consumables to weld the above steel was the only available remedy because of higher solubility for hydrogen in austenitic phase. In this investigation, an attempt was made to determine a suitable consumable to replace expensive austenitic consumables.

G Magudeeswaran; V Balasubramanian; G Madhusudhan Reddy; T S Balasubramanian

2008-01-01

391

Double-sided fiber laser beam welding process of T-joints for aluminum aircraft fuselage panels: Filler wire melting behavior, process stability, and their effects on porosity defects  

NASA Astrophysics Data System (ADS)

Aluminum alloy T-joints for aircraft fuselage panels were fabricated by double-sided fiber laser beam welding with filler wire, and the influence of the wire feeding posture on the welding process stability was investigated. A CMOS high speed video system was used to observe the wire melting behavior and the weld pool dynamics in real time during the welding process by using a bandpass red laser with an emission wavelength of 808 nm as backlight source to illuminate the welding zone. The weld porosity defects were analyzed by X-ray radiography. The effects of wire feeding posture on the wire melting behavior, process stability, and porosity defects were investigated. The experimental results indicated that three distinct filler material transfer modes were identified under different wire feeding positions: liquid bridge transfer mode, droplet transfer mode, and spreading transfer mode. The liquid bridge transfer mode could guarantee a stable welding process, and result in the lowest porosity. Compared with wire feeding in the leading direction, the process was not stable and porosity increased when wire feeding in the trailing direction. Increased in the wire feeding angle was disadvantage for pores to escape from the weld molten pool, meanwhile, it made the welding process window smaller due to increasing the centering precision requirement for adjusting the filler wire.

Tao, Wang; Yang, Zhibin; Chen, Yanbin; Li, Liqun; Jiang, Zhenguo; Zhang, Yunlong

2013-11-01

392

Heat and fluid flow in complex joints during gas metal arc welding-Part II: Application to fillet welding of mild steel  

Microsoft Academic Search

A numerical model described in part I [W. Zhang, C.-H. Kim, and T. DebRoy, J. Appl. Phys. 95, 5210 (2004)] was used to investigate the heat transfer and free surface flow during gas metal arc fillet welding of mild steel. Dimensional analysis was used to understand the importance of heat transfer by conduction and convection and the role of various

W. Zhang; C.-H. Kim; T. Debroy

2004-01-01

393

Direct welding with arc discharging to joint quart optical fiber to multicomponent glass mold lens (small factor fiber collimator with new push-pull welding method)  

NASA Astrophysics Data System (ADS)

In this paper, a new direct splicing method called push-pull welding is described. Direct coupling based on direct fusion splicing, which makes an optical fiber joining a multicomponent glass lens, gives not only a high optical performance but also high reliability and easy alignment.

Koishi, Musubu; Nishizawa, Koichi; Kawai, Shigeru

2011-03-01

394

A robust visual seam tracking system for robotic arc welding  

Microsoft Academic Search

A robotic seam tracking system is developed to achieve robustness against optical noises such as arc glares, welding spatters, fume, and other unexpected brightness sources. The profile data of a weld joint to be welded are reliably extracted using two separate vision processing algorithms: the first is for joint modeling before welding starts, while the second is for joint feature

Jae Seon Kim; Young Tak Son; Hyung Suck Cho; Kwang Il Koh

1996-01-01

395

Method for welding beryllium  

DOEpatents

A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon.

Dixon, Raymond D. (Los Alamos, NM); Smith, Frank M. (Espanola, NM); O' Leary, Richard F. (Los Alamos, NM)

1997-01-01

396

Comparative and Joint Analysis of Two Metagenomic Datasets from a Biogas Fermenter Obtained by 454-Pyrosequencing  

PubMed Central

Biogas production from renewable resources is attracting increased attention as an alternative energy source due to the limited availability of traditional fossil fuels. Many countries are promoting the use of alternative energy sources for sustainable energy production. In this study, a metagenome from a production-scale biogas fermenter was analysed employing Roche's GS FLX Titanium technology and compared to a previous dataset obtained from the same community DNA sample that was sequenced on the GS FLX platform. Taxonomic profiling based on 16S rRNA-specific sequences and an Environmental Gene Tag (EGT) analysis employing CARMA demonstrated that both approaches benefit from the longer read lengths obtained on the Titanium platform. Results confirmed Clostridia as the most prevalent taxonomic class, whereas species of the order Methanomicrobiales are dominant among methanogenic Archaea. However, the analyses also identified additional taxa that were missed by the previous study, including members of the genera Streptococcus, Acetivibrio, Garciella, Tissierella, and Gelria, which might also play a role in the fermentation process leading to the formation of methane. Taking advantage of the CARMA feature to correlate taxonomic information of sequences with their assigned functions, it appeared that Firmicutes, followed by Bacteroidetes and Proteobacteria, dominate within the functional context of polysaccharide degradation whereas Methanomicrobiales represent the most abundant taxonomic group responsible for methane production. Clostridia is the most important class involved in the reductive CoA pathway (Wood-Ljungdahl pathway) that is characteristic for acetogenesis. Based on binning of 16S rRNA-specific sequences allocated to the dominant genus Methanoculleus, it could be shown that this genus is represented by several different species. Phylogenetic analysis of these sequences placed them in close proximity to the hydrogenotrophic methanogen Methanoculleus bourgensis. While rarefaction analyses still indicate incomplete coverage, examination of the GS FLX Titanium dataset resulted in the identification of additional genera and functional elements, providing a far more complete coverage of the community involved in anaerobic fermentative pathways leading to methane formation.

Jaenicke, Sebastian; Ander, Christina; Bekel, Thomas; Bisdorf, Regina; Droge, Marcus; Gartemann, Karl-Heinz; Junemann, Sebastian; Kaiser, Olaf; Krause, Lutz; Tille, Felix; Zakrzewski, Martha; Puhler, Alfred

2011-01-01

397

Research on Narrow Gap Welding Parameters Optimization  

Microsoft Academic Search

The effects of welding voltage, welding current and weld heat input on the A105 steel weld formation quality using submerged-arc welding (SAW) with small diameter welding wire were experimentally researched. Through lots of experiments of surface overlaying on flat plates, the optimal parameters were obtained sequentially using numerical regression analysis. The calculated results were compared with experimental data to verify

Qinghua Lu; Zhishui Yu; Guoxiang Xu; Jianping He

2009-01-01

398

Autonomous Mobile Robot System for Monitoring and Control of Penetration during Fixed Pipes Welding  

NASA Astrophysics Data System (ADS)

In order to obtain sound welded joints in the welding of horizontal fixed pipes, it is important to control the back bead width in the first pass. However, it is difficult to obtain optimum back bead width, because the proper welding conditions change with welding position. In this paper, in order to fully automatize the welding of fixed pipes, a new method is developed to control the back bead width with monitoring the shape and dimensions of the molten pool from the reverse side by autonomous mobile robot system. This robot has spherical shape so as to move in a complex route including curved pipe, elbow joint and so on. It has also a camera to observe inner surface of pipe and recognize a route in which the robot moves. The robot moves to welding point in the pipe, and monitors the reverse side shape of molten pool during welding. The host computer processes the images of molten pool acquired by the robot vision system, and calculates the optimum welding conditions to realize adaptive control of welding. As a result of the welding control experiments, the effectiveness of this system for the penetration control of fixed pipes is demonstrated.

Muramatsu, Masahiro; Suga, Yasuo; Mori, Kazuhiro

399

Joining characteristics of orthodontic wires with laser welding.  

PubMed

Laser welding 0.016 x 0.022 in. beta-Ti, Ni-Ti, and Co-Cr-Ni orthodontic wires was investigated by measuring joint tensile strength, measuring laser penetration depth, determining metallurgical phases using micro X-ray diffraction (micro-XRD), and examining microstructures with an scanning electron microscope (SEM). Welding was performed from 150 to 230 V. Mean tensile strength for Ni-Ti groups was significantly lower (p < 0.05) than for most other groups of laser-welded specimens. Although mean tensile strength for beta-Ti and Co-Cr-Ni was significantly lower than for control specimens joined by silver soldering, it was sufficient for clinical use. The beta-Ti orthodontic wire showed deeper penetration depth from laser welding than the Ni-Ti and Co-Cr-Ni orthodontic wires. Micro-XRD patterns of laser-welded beta-Ti and Ni-Ti obtained 2 mm from the boundary were similar to as-received specimens, indicating that original microstructures were maintained. When output voltages of 190 V and higher were used, most peaks from joint areas disappeared or were much weaker, perhaps because of a directional solidification effect, evidenced by SEM observation of fine striations in welded beta-Ti. Laser welding beta-Ti and Co-Cr-Ni wires may be acceptable clinically, since joints had sufficient strength and metallurgical phases in the original wires were not greatly altered. PMID:17514661

Iijima, Masahiro; Brantley, William A; Yuasa, Toshihiro; Muguruma, Takeshi; Kawashima, Isao; Mizoguchi, Itaru

2008-01-01

400

Effects of process time and thread on tensile shear strength of Al alloy lap joint produced by friction stir spot welding  

Microsoft Academic Search

In automotive applications, friction stir spot welding (FSSW) has been practically used in the construction of aluminium car bodies. In this study, the weld strength and factors governing the weld strength in the friction stir spot welded aluminium alloy 6061-T6 were examined. The weld strength increased with the process time during FSSW up to 3 s, beyond which it decreased. The

Mitsuo Fujimoto; Daisuke Watanabe; Natsumi Abe; Sato S. Yutaka; Hiroyuki Kokawa

2010-01-01

401

Diffusion Weld Test Fixture.  

National Technical Information Service (NTIS)

A weld joint test fixture for testing the strength of a weld joining several members forming a test specimen is provided. The fixture includes a base which supports the test specimen and an attachment for applying a testing force to the test specimen whil...

W. Maciejewski R. Tyron G. Kavarnos E. McLaughlin K. Janecek

1994-01-01

402

Fusion Welding of Irradiated AISI 304L Stainless Steel Tubings.  

National Technical Information Service (NTIS)

Fast reactor irradiated AISI 304L stainless steel tubing was fusion-welded using conventional inert gas-tungsten arc welding (GTAW) procedures which were adapted for remote operation. Metallographic examination of weld joints sometimes revealed porosity i...

M. M. Hall A. G. Hins J. R. Summers D. E. Walker

1978-01-01

403

Effects of residual stress, weld toe notch and weld defects on fatigue of welded steel structures  

Microsoft Academic Search

In studying the fatigue behavior of fillet welded railroad tank car shell structures, the effects of welding residual stress, weld toe notch, and weld defects on the fatigue of fillet welded A515 steel specimens were evaluated. Both hole-drilling and sectioning measurement techniques were used to obtain residual stress information. Pad-on-plate weld specimens were designed to simulate the tank car structure

Wenyu Shen

1992-01-01

404

COD\\/Kcv correlations in weld deposits in butt joints produced by the MMA, MIG and SAW processes in an HSLA steel with a yield strength of 480 N\\/mm  

Microsoft Academic Search

Using the Okazaki method, relationships were obtained between the experimental COD values and the COD values calculated from the yield strength, ductile\\/brittle transition temperature and impact energy values for weld deposits made by manual metal arc with coated electrodes, MIG and SAW in the as?welded state and with intermediate and final heat treatments. Average values for these relationships in the

M. A. Roman; E. Ayala

1993-01-01

405

Modified Wöhler curve method, theory of critical distances and Eurocode 3: A novel engineering procedure to predict the lifetime of steel welded joints subjected to both uniaxial and multiaxial fatigue loading  

Microsoft Academic Search

In order to propose a procedure suitable for assessing steel welded joints by post-processing simple linear-elastic finite element (FE) models, this paper summarises an attempt to formalise a novel approach based on the use of the modified Wöhler curve method (MWCM) applied along with the theory of critical distances (TCD). This engineering procedure was initially calibrated by using the standard

L. Susmel

2008-01-01

406

Development of the main requirements for contemporary systems of radiographic testing including digital image processing taking into account specific features of inspection of welded joints of oil and gas pipelines (a review)  

Microsoft Academic Search

Contemporary radiographic systems with digital image processing for testing welded joints of oil and gas pipelines are analyzed.\\u000a The main requirements for systems for computer interpretation and archiving of radiographic images and personnel interpreting\\u000a radiograms are formulated.

E. A. Alekhnovich; N. E. Van’kova; V. I. Kapustin; A. I. Karpenko; T. N. Maksimova

2008-01-01

407

Comparison of creep crack growth rate in heat affected zone of welded joint for 9%Cr ferritic heat resistant steel based on C ?, d ?\\/d t, K and Q ? parameters  

Microsoft Academic Search

Creep crack growth behavior is very sensitive to the materials’ micro-structures such as the heat affected zone of a weld joint. This is a main issue to be clarified for 9%Cr ferritic heat resistant steel for their application in structural components. In this paper, high temperature creep crack growth tests were conducted on CT specimens with cracks in the heat

R. Sugiura; A YOKOBORIJR; M. Tabuchi; T. Yokobori

2007-01-01

408

Data on the Fatigue Resistance of Welded Joints AlMgG5, Volume 1 Raccolta di Dati Sulla Resistenza a Fatica Dei Giunti Saldati in Al Mg5.  

National Technical Information Service (NTIS)

A collection of S-N curves for welded joints in aluminum alloys containing from 3% to 5.5% of magnesium is presented. The series of experimental results taken from the literature are reported in tables and diagrams in a unified manner. The data are reanal...

B. Atzori R. Bufano

1976-01-01

409

Effects of plastic restraint on strain at the crack tip in the ductile fracture process: Study on evaluation of stable crack growth resistance of mismatched welded joints (2nd Report)  

Microsoft Academic Search

The previous paper has shown that strength mismatch significantly affects stable crack growth resistance, warranting extensive experimental and theoretical work to be done to establish a method for evaluation of defects in heterogeneous materials, such as welded joints.This paper describes an investigation of the effect of the strength mismatch and plastic restraint on equivalent plastic strain at the stable crack

K. Michiba; H. Hiramatsu; H. Hasegawa; H. Matsumura; M. Toyoda

1997-01-01

410

Development of an intelligent system for cooling rate and fill control in GMAW. [Gas Metal Arc Welding (GMAW)  

SciTech Connect

A control strategy for gas metal arc welding (GMAW) is developed in which the welding system detects certain existing conditions and adjusts the process in accordance to pre-specified rules. This strategy is used to control the reinforcement and weld bead centerline cooling rate during welding. Relationships between heat and mass transfer rates to the base metal and the required electrode speed and welding speed for specific open circuit voltages are taught to a artificial neural network. Control rules are programmed into a fuzzy logic system. TRADITOINAL CONTROL OF THE GMAW PROCESS is based on the use of explicit welding procedures detailing allowable parameter ranges on a pass by pass basis for a given weld. The present work is an exploration of a completely different approach to welding control. In this work the objectives are to produce welds having desired weld bead reinforcements while maintaining the weld bead centerline cooling rate at preselected values. The need for this specific control is related to fabrication requirements for specific types of pressure vessels. The control strategy involves measuring weld joint transverse cross-sectional area ahead of the welding torch and the weld bead centerline cooling rate behind the weld pool, both by means of video (2), calculating the required process parameters necessary to obtain the needed heat and mass transfer rates (in appropriate dimensions) by means of an artificial neural network, and controlling the heat transfer rate by means of a fuzzy logic controller (3). The result is a welding machine that senses the welding conditions and responds to those conditions on the basis of logical rules, as opposed to producing a weld based on a specific procedure.

Einerson, C.J.; Smartt, H.B.; Johnson, J.A.; Taylor, P.L. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Moore, K.L. (Idaho State Univ., Pocatello, ID (United States))

1992-01-01

411

Effect of welding parameters on microstructure in the stir zone of FSW joints of aluminum die casting alloy  

Microsoft Academic Search

The effect of the welding speed and the rotation speed on the microstructure in the stir zone has been investigated by measuring the Si particle distribution in the ADC12 alloy. The stir zone has fine recrystallized grains without dendritic structures, and the eutectic Si was uniformly dispersed in the stir zone. The size of the Si particles was statistically determined

Y. G. Kim; H. Fujii; T. Tsumura; T. Komazaki; K. Nakata

2006-01-01

412

Comparison of the Measured and Calculated Creep Strains Occurring in Internally Pressurized Cylindrical Butt-Welded Joints.  

National Technical Information Service (NTIS)

The report outlines the work undertaken to produce two pressure vessels, based on 1/2Cr1/2Mo1/4V main steampipe and containing mild steel, 1CrMo, 2CrMo and 1/2CrMoV weld metals, and their testing at 565 C and 455 bar internal steam pressure. The experimen...

D. J. Walters M. C. Coleman

1989-01-01

413

Laser and shot peening effects on fatigue crack growth in friction stir welded 7075-T7351 aluminum alloy joints  

Microsoft Academic Search

The influence of shot and laser peening on the fatigue crack growth behavior of friction stir welded (FSW) aluminum alloy (AA) 7075-T7351 sheets was investigated. The alterations resulting from this surface modification on the fatigue crack growth of FSW were characterized and evaluated for two different crack configurations. A systematic investigation of the various peening effects indicated a significant decrease

Omar Hatamleh; Jed Lyons; Royce Forman

2007-01-01

414

Experimental investigation on mechanical behavior of friction welded AL7075  

Microsoft Academic Search

Friction welding is widely used as a mass production method in various industries. In friction welding, the joints are formed in the solid state by utilizing the heat generated by friction. Friction welding can be used to join different types of ferrous metals and non-ferrous metals that cannot be welded by traditional welding processes. The process parameters such s friction

M Rajendran

2012-01-01

415

General Mechanical Repair. Welding. Volume 2. Teacher's Guide.  

ERIC Educational Resources Information Center

|Five units on welding are presented in this teacher's guide. The units are the following: introduction to oxyacetylene welding, oxyacetylene welding positions and applications, use of the cutting torch, introduction to shielded metal arc welding, and welding joints and positions. Each instructional unit generally contains eight components:…

East Texas State Univ., Commerce. Occupational Curriculum Lab.

416

Pattern recognition of super-alloy friction welding joint defect by wavelet packet and wavelet neural network  

Microsoft Academic Search

Detecting the super-alloy friction welding specimens of GH4169 by using the UltraPAC system, aiming at the characteristic of defects, the method of analyzing and extracting the defect eigenvalue by using wavelet packet analysis and pattern recognition by making use of the wavelet neural network is discussed. This method can realize to extract the interrelated information which can reflect defect characteristic

Xin Yin; Zhen Zhang; Ai-Min Liu; Qi-Lin Li

2007-01-01

417

Influence of plate thickness on the mechanical properties of welded joints subjected to long-term postweld heat treatments  

Microsoft Academic Search

During their service lives, storage spheres, pressure vessels, and other welded structures are subjected frequently to postweld\\u000a heat treatments (PWHT). Repeated treatments may result, in some cases, in a reduction in mechanical strength and fracture\\u000a toughness of the weldments such that their mechanical properties may not meet the code specifications after those treatments.\\u000a Steel ASTM-A-516 Gr 70 is used frequently

G. Pimenta; F. Bastian

2002-01-01

418

Low cycle fatigue properties of modified 9Cr1Mo ferritic martensitic steel weld joints in sodium environment  

Microsoft Academic Search

Mod.9Cr-1Mo ferritic-martensitic steel is the material chosen for the steam generator of the Prototype Fast Breeder Reactor\\u000a being built at Kalpakkam, India. The use of sodium as a heat transfer medium for Liquid Metal Fast Breeder Reactors (LMFBRs)\\u000a necessitates a comprehensive understanding of the effects of dynamic sodium on the Low Cycle Fatigue (LCF) behaviour of structural\\u000a components. Moreover welds

R. Sandhya; R. Kannan; V. Ganesan; M. Valsan; K. Bhanu Sankara Rao

2010-01-01

419

Microstructure and mechanical properties of an inertia friction welded INCOLOY alloy 909–INCONEL alloy 718 joint for rotating applications  

Microsoft Academic Search

Inertia welding is a common practice to join axially symmetrical parts for aero-engine applications. The shaft for a new advanced high-pressure compressor will be produced ed by joining the high strength superalloys INCOLOY® alloy 909 (Incoloy909) and INCONEL® alloy 718 (IN718). IN718 is the work-horse nickel-iron-chromium alloy for a variety of parts for aero-engine applications due to a good combination

O. Roder; J. Albrecht; G. Lütjering

2006-01-01

420

Parametric Studies Of Weld Quality Of Tungsten Inert Gas Arc Welding Of Stainless Steel  

Microsoft Academic Search

Effect of current and gas flow rate on quality of weld in tungsten inter gas arc welding of austenitic stainless steel has been studied in the present work through experiments and analyses. Butt welded joints have been made by using several levels of current and gas flow rate. The quality of the weld has been evaluated in terms of ultimate

Pradip Kumar Pal; Goutam Nandi; Nabendu Ghosh

2011-01-01

421

WELDING PROCESS  

DOEpatents

A method of joining metal parts for the preparation of relatively long, thin fuel element cores of uranium or alloys thereof for nuclear reactors is described. The process includes the steps of cleaning the surfaces to be jointed, placing the sunfaces together, and providing between and in contact with them, a layer of a compound in finely divided form that is decomposable to metal by heat. The fuel element members are then heated at the contact zone and maintained under pressure during the heating to decompose the compound to metal and sinter the members and reduced metal together producing a weld. The preferred class of decomposable compounds are the metal hydrides such as uranium hydride, which release hydrogen thus providing a reducing atmosphere in the vicinity of the welding operation.

Zambrow, J.; Hausner, H.

1957-09-24

422

Welding of Duplex Stainless Steel Composite Plate: Influence on Microstructural Development  

Microsoft Academic Search

In the present study, the duplex stainless steel (DSS) composite plate (SAF2205\\/16MnR) was welded by shielded metal arc welding, and the appropriate joint design and welding procedure were carried out. After welding, the mechanical behaviors and microstructure of welded joint were analyzed by using SEM and TEM. Results show that the tensile strength of welded joint satisfied the requirement, and

Shao-Gang Wang; Gui-Ping Dong; Qi-Hui Ma

2009-01-01

423

Research on laser welding of aluminum matrix composite SiCw\\/6061  

Microsoft Academic Search

Effects of laser welding parameters on strength of welded joint were studied. Mechanism of loss of joint strength was analyzed. It was pointed out that an important factor affecting joint strength is the reaction between matrix and reinforced phase. On the basis of this, the concept of critical Si activity was proposed. In appropriate welding parameters and Si activity, welded

Jitai Niu; Longxiu Pan; Muzhen Wang; Chengbin Fu; Xiaodong Meng

2006-01-01

424

Modeling and optimization of tensile shear strength of Titanium\\/Aluminum dissimilar welded component  

Microsoft Academic Search

Titanium was successfully welded to Aluminum using laser welding. Laser welding parameters ranges combinations were experimentally determined using Taguchi approach with the objective of producing welded joint with acceptable welding profile and maximizing the tensile shear strength. Tensile shear strength of dissimilar Al\\/Ti was evaluated as a response function of the selected laser welding parameters and statistical model was developed

E. M. Anawa; A. G. Olabi; F. A. Elshukri

2009-01-01

425

Welding Study of Electroslag Remelted Steel Armor.  

National Technical Information Service (NTIS)

The purpose of the project was to study welding of electroslag remelted (ESR) steel with high strength filler wires. This report gives a detailed description of welding techniques developed, and a metallurgical and ballistic evaluation of the welds obtain...

L. L. Lanier R. E. Musante W. C. Schultz

1974-01-01

426

Fractured welds stir not debate  

SciTech Connect

This article reviews the growing discussion regarding the failures of welded joints in a number of beam-to-column connections. In the Northridge Earthquake of 1994, there were a large number of such failures, and weld material E70T-4 was the common element in each failure. This weld material is utilized with FCAW, a semiautomatic welding process that allows a higher deposition rate. The manufacturer of the weld material argues that many of the welds were improperly performed, while others argue that the fracture toughness of the weld material is very low. With a minor defect, this would lead to brittle fracture under the cyclic loading that would occur during a seismic event. Use of the manual SMAW process using weld material E7018 is recommended.

Rosenbaum, D.B.; Stocker, L.J.P.

1996-05-06

427

Joint Variability of Airborne Passive Microwave and Ground-based Radar Observations Obtained in the TRMM Kwajalein Experiment  

NASA Astrophysics Data System (ADS)

The Tropical Rainfall Measuring Mission (TRMM) Kwajalein Experiment (KWAJEX) held July-September 1999 in the west Pacific was designed to obtain an empirical physical characterization of precipitating convective clouds over the tropical ocean. The majority of the precipitation was from mixed-phase clouds. Coordinated data sets were obtained from aircraft and ground-based sensors including passive microwave measurements by the Advanced Microwave Precipitation Radiometer (AMPR) instrument on the NASA DC-8 aircraft and S-band volumetric radar data by the KPOL radar. The AMPR and KPOL data sets were processed to yield a set of 25,049 matching observations at ~ 2 km x 2 km horizontal spatial resolution and within 6 min. The TRMM satellite Microwave Imager (TMI) has a similar set of channels to AMPR but coarser spatial resolution (19 GHz: 35 km, 85 GHz: 7.7 km). During KWAJEX, the 0 deg C level height was nearly constant at ~ 4800 m. Hence, two potential sources of uncertainty in relating passive microwave brightness temperatures (Tbs) to surface precipitation, inhomogeneous beam filling and variations in depth of the rain layer are much smaller sources of error in the KWAJEX data set than for TMI. TRMM was originally designed to yield monthly rainfall estimates over 5 deg x 5 deg grid boxes. The use of these data to yield instantaneous rainrate products at smaller spatial scales is more sensitive to the detailed characteristics of the joint distributions of passive microwave Tbs versus rain rate. KWAJEX data sets reveal poor correlations, very wide scatter, and weak modes in these distributions. The spread of emission Tb values for a given rain-layer reflectivity (e.g., 75 K at 30 dBZ for 19 GHz) is similar or larger within convective compared to stratiform precipitation regions. This result implies that the enhancement in emission Tbs associated with partially melted ice particles can occur whether the particles are concentrated within a thin layer in stratiform regions or are more dispersed in the column in convective regions. There is little information in either ice-layer radar reflectivity or scattering (85 GHz) Tbs on the underlying quantitative surface rain rates at the spatial scale examined.

Yuter, S. E.; Kingsmill, D. E.

2007-12-01

428

Bond Strength of Gold Alloys Laser Welded to Cobalt-Chromium Alloy  

PubMed Central

The objective of this study was to investigate the joint properties between cast gold alloys and Co-Cr alloy laser-welded by Nd:YAG laser. Cast plates were fabricated from three types of gold alloys (Type IV, Type II and low-gold) and a Co-Cr alloy. Each gold alloy was laser-welded to Co-Cr using a dental laser-welding machine. Homogeneously-welded and non-welded control specimens were also prepared. Tensile testing was conducted and data were statistically analyzed using ANOVA. The homogeneously-welded groups showed inferior fracture load compared to corresponding control groups, except for Co-Cr. In the specimens welded heterogeneously to Co-Cr, Type IV was the greatest, followed by low-gold and Type II. There was no statistical difference (P<0.05) in fracture load between Type II control and that welded to Co-Cr. Higher elongations were obtained for Type II in all conditions, whereas the lowest elongation occurred for low-gold welded to Co-Cr. This study indicated that, of the three gold alloys tested, the Type IV gold alloy was the most suitable alloy for laser-welding to Co-Cr.

Watanabe, Ikuya; Wallace, Cameron

2008-01-01

429

Efficient Weld Seam Detection for Robotic Welding from a Single Image  

Microsoft Academic Search

The weld seam recognition is a key technology in robotic welding. This paper presents an efficient algorithm of weld seam\\u000a detection for butt joint welding from a single image. The basic idea of our approach is to find a pair of weld seam edges\\u000a in the local area first. Then, starting from the two endpoints of each edge, search for

Fanhuai Shi; Lv Zhou; Tao Lin; Shanben Chen

430

EXPERIMENTAL STUDY ON THE EFFECT OF ROTATIONAL SPEED AND TOOL PIN PROFILE ON AA2024 ALUMINIUM FRICTION STIR WELDED BUTT JOINTS  

Microsoft Academic Search

Friction stir welding (FSW) is a novel solid state welding process for joining metallic alloys and has been employed in several industries such as aerospace and automotive for joining aluminium, magnesium and copper alloys. The various parameters such as rotational speed, longitudinal speed, axial force and attack angle play vital roles in FSW process in order to analyse the weld

P. Bahemmat; A. Rahbari; M. Haghpanahi; M. K. Besharati

431

3-D finite element analysis of stress concentration factor in spot-welded joints of steel: The effect of process-induced porosity  

Microsoft Academic Search

The work presented in this paper utilises a numerical analysis for the computation of stress concentration factor generated by the presence in the weld nugget of a pore formed during the welding process. Welded structure containing porosity is subjected to uniaxial tensile stress. The effects of geometrical parameters of the pore and the interaction pore-defect on the stress concentration factor

Farida Bouafia; Serier Boualem; Mecirdi Mohamed El Amin; Boutabout Benali

2011-01-01

432

Effect of post?weld heat treatment on properties of commercially pure titanium\\/pure aluminium friction welds. Study of friction welding of titanium\\/aluminium (1st report)  

Microsoft Academic Search

This paper describes a fundamental investigation of the friction welding conditions for commercially pure titanium\\/pure aluminium joints and the effect of post?weld heat treatment (PWHT) on the mechanical and metallurgical properties of friction welds. The investigation also clarifies the range of friction welding conditions able to ensure production of fracture?free welded joints having more than 100% joint efficiency in tensile

A. Fuji; K. Ameyama; M. Futamata; Y. Shimaki

1994-01-01

433

Method for welding beryllium  

DOEpatents

A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon. 9 figs.

Dixon, R.D.; Smith, F.M.; O`Leary, R.F.

1997-04-01

434

Weld braze technique  

SciTech Connect

High-strength metal joints are formed by a combined weld-braze technique. A hollow cylindrical metal member is forced into an undersized counterbore in another metal member with a suitable braze metal disposed along the bottom of the counterbore. Force and current applied to the members in an evacuated chamber results in the concurrent formation of the weld along the sides of the counterbore and a braze along the bottom of the counterbore in one continuous operation.

Alexander, R.J.; Kanne, W.R.; Kelker, J.W.

1982-04-20

435

Joining of stainless-steel and aluminium materials by friction welding  

Microsoft Academic Search

The joining of dissimilar materials is of great importance in industry. Especially, if it is used as the lightest part of\\u000a the machine parts, materials such as aluminium and magnesium can be joined with different steels. Therefore, in this study,\\u000a austenitic stainless-steel and aluminium materials were welded using the friction welding method. Optimum parameters for joints\\u000a were obtained by using

Mumin Sahin

2009-01-01

436

Temperature Criterion of Laser Welding for Joining Aluminum Alloy with Low-Carbon Steel  

Microsoft Academic Search

Aluminum alloy and low-carbon steel are dissimilar metals. In order to obtain a reciprocal comprehensive property in a joint component of aluminum alloy and low-carbon steel, laser welding was used as a novel joining process. Based on the experimental results, the temperature criterion of laser welding for joining of aluminum alloy and low-carbon steel is discussed in this paper.

J. J. Ding; H. J. Huang; P. Peyre; R. Fabbro

2006-01-01

437

Weld features that differentiate weld and plate corrosion  

Microsoft Academic Search

Corrosion is an environmentally assisted damage that professionals face daily, particularly with welded structures. Fusion\\u000a welds result from solidification and solid-state transformations induced by well-localized thermal cycles. A fusion weld joint\\u000a inherently exhibits an irregular surface as well as gradients in chemical composition, microstructure, properties, and residual\\u000a stress, depending on process parameters and part geometry. This article analyzes the roles

D. L. Olson; A. N. Lasseigne; M. Marya; B. Mishra

2003-01-01

438

The influence of process parameters and tool geometry on mechanical properties of friction stir welded aluminum lap joints  

Microsoft Academic Search

The results of an experimental investigation on the lap joining of AA6022-T4 aluminum alloy blanks by FSW are reported in\\u000a the present paper; in particular, the joints strength was investigated. The experimental campaign was performed on sheets\\u000a having a thickness of 1.2 mm, lap joined by means of a CNC machine tool. Several tests were carried out by varying process

G. D’Urso; C. Giardini

2010-01-01

439

Post-earthquake fire and seismic performance of welded steel–concrete composite beam-to-column joints  

Microsoft Academic Search

The performance of steel–concrete composite full strength joints endowed with concrete filled tubes, designed with a multi-objective methodology dealing with seismic actions followed by fire is presented in this paper. In detail, instead of a traditional single-objective design where fire safety and seismic safety are independently achieved and the sequence of seismic and fire loading are not taken into account,

R. Pucinotti; O. S. Bursi; J. F. Demonceau

2011-01-01

440

Cadcam welding in steel bridge panel fabrication  

Microsoft Academic Search

Describes the use of welding robots for making bridge panels. The system uses a total of 14 sets of High Speed Rotating Arc welding robots and newly-developed arc sensor techniques are used with both joint end and bead end sensors. A teaching-less direct CADCAM system was developed to control the robots. The welding robot system is now in commercial operation

Yuji Sugitani; Yoshihiro Kanjo; Masatoshi Murayama

1994-01-01

441

Welding Copper to Itself and to Steel.  

National Technical Information Service (NTIS)

Five applications have been described in which oxygen-free copper was joined either to itself or to steel. Braze welding and the use of transition welds were utilized on dissimilar metal joints. Welding was performed with either the gas tungsten-arc proce...

D. Gillespie L. C. Watson P. W. Turner R. L. Mcllwain W. C. Collins

1976-01-01

442

Nd:YAG laser welding aluminum alloys.  

National Technical Information Service (NTIS)

Autogenous Nd:YAG laser welding wrought 4047, 1100, 3003, 2219, 5052, 5086, 5456, and 6061 and cast A356 aluminum alloys to cast A356 aluminum alloy in restrained annular weld joints was investigated. The welds were 12.7 mm (0.375 in.) and 9.5 mm (0.375 i...

E. Jimenez

1992-01-01

443

Advances in welding science - a perspective.  

National Technical Information Service (NTIS)

The ultimate goal of welding technology is to improve the joint integrity and increase productivity. Over the years, welding has been more of an art than a science, but in the last few decades major advances have taken place in welding science and technol...

S. A. David J. M. Vitek S. S. Babu T. DebRoy

1995-01-01

444

Numerical Simulation on Joining of Ceramics with Metal by Friction Welding Technique  

NASA Astrophysics Data System (ADS)

The joining of ceramic and metals can be done by different techniques such as ultrasonic joining, brazing, transient liquid phase diffusion bonding, and friction welding. Friction Welding is a solid state joining process that generates heat through mechanical friction between a moving workpiece and a stationary component. In this article, numerical simulation on thermal analysis of friction welded ceramic/metal joint has been carried out by using Finite Element Analysis (FEA) software. The finite element analysis helps in better understanding of the friction welding process of joining ceramics with metals and it is important to calculate temperature and stress fields during the welding process. Based on the obtained temperature distribution the graphs were plotted between the lengths of the joint corresponding to the temperatures. To increase the wettability, aluminium sheet was used as an interlayer. Hence, numerical simulation of friction welding process is done by varying the interlayer sheet thickness. Transient thermal analysis had been carried out for each cases and temperature distribution was studied. From the simulation studies, it is found that the increase in interlayer thickness reduces the heat affected zone and eventually improves the joint efficiency of alumina/aluminum alloy joints.

Jesudoss Hynes, N. Rajesh; Nagaraj, P.; Basil, S. Joshua

445

Laser welding of thermoplastic materials.  

PubMed

The capabilities of the three main types of laser are compared and a new technique is introduced, which laser welds plastics using an infrared absorber to create a joint that is almost invisible to the human eye. PMID:11488201

Chipperfield, F A; Jones, I A

2001-06-01

446

Comparative investigation of tungsten inert gas and friction stir welding characteristics of Al–Mg–Sc alloy plates  

Microsoft Academic Search

Al–Mg–Sc alloy plates were welded by FSW and TIG welding. The effect of welding processes on mechanical properties of Al–Mg–Sc welded joints was analyzed based on optical microscopy, transmission electron microscopy, tensile testing and Vickers microhardness measurements. The results show that the mechanical properties of FSW welded joint are much better than those of TIG welded joint; the strength coefficient

Juan Zhao; Feng Jiang; Haigen Jian; Kang Wen; Long Jiang; Xiaobo Chen

2010-01-01

447

Friction Stir Spot Welding of DP780 Carbon Steel  

SciTech Connect

Friction stir spot welds were made in uncoated and galvannealed DP780 sheets using polycrystalline boron nitride stir tools. The tools were plunged at either a single continuous rate or in two segments consisting of a relatively high rate followed by a slower rate of shorter depth. Welding times ranged from 1 to 10 s. Increasing tool rotation speed from 800 to 1600 rev min{sup -1} increased strength values. The 2-segment welding procedures also produced higher strength joints. Average lap shear strengths exceeding 10 {center_dot} 3 kN were consistently obtained in 4 s on both the uncoated and the galvannealed DP780. The likelihood of diffusion and mechanical interlocking contributing to bond formation was supported by metallographic examinations. A cost analysis based on spot welding in automobile assembly showed that for friction stir spot welding to be economically competitive with resistance spot welding the cost of stir tools must approach that of resistance spot welding electrode tips.

Santella, Michael L [ORNL; Hovanski, Yuri [ORNL; Frederick, David Alan [ORNL; Grant, Glenn J [ORNL; Dahl, Michael E [ORNL

2010-01-01

448

Laser welding of bone: Successful in vitro experiments  

SciTech Connect

A method for ``welding`` bones is being developed. Tensile joint strengths of chicken bones welded in vitro have exceeded one kilogram. Welding was performed with either a Nd:YAG (1064 nm) or a diode laser (820 nm). Light was delivered with an optical fiber held a few millimeters from the bone surface. A solder was developed to assist in the welding process.

Mourant, J.R.; Anderson, G.D.; Bigio, I.J.; Johnson, T.M.

1994-02-01

449

Simulation of Impulse Resistance Welding for Thermoplastic Matrix Composites  

Microsoft Academic Search

The impulse resistance welding (IRW) process is modelled using a three-dimensional transient finite element model (FEM) featuring heat transfer and consolidation. The welding of single lap joints is simulated for APC-2 laminates, with additional PEEK film inserted at the welding interface. The effects of the power signal on (a) temperature uniformity in the welding interface and (b) processing times are

Christophe Ageorges; Lin Ye

2001-01-01

450

Structural evaluation of a butt-welded elbow end: a simplified procedure  

SciTech Connect

Explicit piping design procedures are not provided in the ASME Code for structural evaluation of ovalization and fabrication effects at the butt-welded end of an elbow. This paper presents a conservative semi-analytical procedure that can be used with elastic as well as inelastic analysis to evaluate an elbow cross section welded to a straight pipe. The concept of carry-over factors is used to obtained ovalization stresses strains at the elbow end. The stresses introduced by material and geometric nonuniformities in the fabrication process are then added to the ovalization stresses to complete structural evaluation of the girth butt-welded elbow joint.

Dhalla, A.K.

1984-08-01

451

Restraint effects in laser welding of an aluminum MMC  

Microsoft Academic Search

Laser beam welding (LBW) of an aluminium metal matrix composite (alloy A40) with a low coefficient of thermal expansion has been investigated. It was found that the cracking propensity of this alloy when laser welded is affected considerably by the restraint conditions at the weld joint. A low restraint joint geometry was chosen that resulted in the completion of crack

P. W. Fuerschbach; M. J. Cieslak

1994-01-01

452

Effects of friction stir welding on microstructure of 7075 aluminum  

Microsoft Academic Search

Friction stir welding is a relatively new technique developed by The Welding Institute (TWI) for the joining of aluminum alloys. The technique, based on friction heating at the faying surfaces of two pieces to be joined, results in a joint created by interface deformation, heat, and solid-state diffusion. In evaluating friction stir welding, critical issues (beyond a sound joint) include

C. G. Rhodes; M. W. Mahoney; W. H. Bingel; R. A. Spurling; C. C. Bampton

1997-01-01

453

Real-time sensing and monitoring in robotic gas metal arc welding  

NASA Astrophysics Data System (ADS)

A real-time monitoring system is developed for detecting abnormal conditions in robotic gas metal arc welding. The butt-joint test pieces with simulated large gaps are used to intentionally introduce step disturbance of welding conditions. During the welding process, the welding voltage and current signals are sampled and processed on-line to extract the characteristic information reflecting the process quality. After the first statistical processing, it is found that seven statistical parameters (the mean, standard deviation, coefficient of variance and kurtosis of welding voltage; the mean, coefficient of variance and kurtosis of welding current) show variations during the step disturbance. Through the second statistical processing of the means of the welding voltage for subgroups of continuous measurement, the statistical control chart is obtained, and an SPC (statistical process control)-based on-line identifying method is developed. Ten robotic welding experiments are conducted to verify the real-time monitoring system. It is found that the correct identification rates for normal and abnormal welding conditions are 100% and 95%, respectively.

Wu, C. S.; Gao, J. Q.; Hu, J. K.

2007-01-01

454

On-line weld position control for fusion reactor welding  

NASA Astrophysics Data System (ADS)

Infrared sensing techniques were investigated to assist remote welding systems to identify and correct weld-joint offsets in real time. During the welding process, the temperature distribution along a line normal to the joint and ahead of the arc was measured. A distinct drop in the measured temperature distribution was observed to coincide with a gap in the joints. In the temperature gradient profile, the gap was characterized by three changes in sign. The second change in sign of the temperature gradient profile was found to correspond to the gap center. The first and third changes in sign were found to coincide with the edges of the joint. These unique changes were used to successfully track curved contours of joints with a gap.

Nagarajan, S.; Wikle, H. C.; Chin, B. A.

1992-09-01

455

Human bones obtained from routine joint replacement surgery as a tool for studies of plutonium, americium and 90Sr body-burden in general public  

Microsoft Academic Search

The paper presents a new sampling method for studying in-body radioactive contamination by bone-seeking radionuclides such as 90Sr, 239+240Pu, 238Pu, 241Am and selected gamma-emitters, in human bones. The presented results were obtained for samples retrieved from routine surgeries, namely knee or hip joints replacements with implants, performed on individuals from Southern Poland. This allowed to collect representative sets of general

Jerzy W. Mietelski; Edward B. Golec; Ewa Tomankiewicz; Joanna Golec; Sebastian Nowak; El?bieta Szczygiel; Kamil Brudecki

2011-01-01

456

Thermal Bonding of Thermoplastic Composites: Influence of Matrix and Interlayer on the Weld Fracture Toughness.  

National Technical Information Service (NTIS)

The various factors influencing the toughness of welded joints in thermoplastic composites are investigated. Three factors are identified as having a positive influence on weld quality. The use of an interlayer which creates fiber migration in the joint z...

B. Goffaux I. Verpoest

1990-01-01

457

MODELLING OF THERMAL PROCESSES IN A DISSYMMETRICAL WELDED CAST ALUMINIUM DESIGNS  

Microsoft Academic Search

Number of constructions, produced from eutectic silumins are continually increasing, therefore problem of their welding became very actual. Eutectic aluminium - silicon alloys are sensitive to changes of a welding thermal cycle. These cast aluminium alloys constructions after welding have large residual stresses, and mechanical properties of welded joint deteriorate. It is difficult to define welding regime in case of

N. Višniakov; D. Š?ekaturovien?; O. ?ernaš?jus

458

Sensitivity analysis for process parameters influencing weld quality in robotic GMA welding process  

Microsoft Academic Search

Generally, the quality of a weld joint is strongly influenced by process parameters during the welding process. In order to achieve high quality welds, mathematical models that can predict the bead geometry to accomplish the desired mechanical properties of the weldment should be developed. This paper focuses on development of mathematical models for the selection of process parameters and the

I. S. Kim; Y. J. Jeong; I. J. Son; I. J. Kim; J. Y. Kim; I. K. Kim; Prasad K. D. V. Yaragada

2003-01-01

459

FRICTION-STIR-LAP-WELDS OF AA6111 ALUMINUM ALLOY  

SciTech Connect

Lap joints of 1 mm thick AA6111 aluminum sheets were made by friction stir welding, using robotic and conventional machines. Welds were made for advancing as well as retreating side loading. Thinning in welds was quantified. Lap shear test of welds was conducted in as-welded and paint-baked conditions. Conventional machine welds showed less thinning and better strength than robotic machine welds. Process forces in conventional machine welding were higher. Paint bake treatment improved the weld strength; but the improvement varied with process parameters. Advancing side loaded welds achieved higher strength than the retreating side loaded welds. Fracture location was found to occur on the loaded side of the weld and along the thinning defect.

Yadava, Manasij; Mishra, Rajiv S.; Chen, Y. L.; Gayden, X.; Grant, Glenn J.

2007-01-09

460

Fatique Resistant, Energy Efficient Welding Program, Final Technical Report  

SciTech Connect

The program scope was to affect the heat input and the resultant weld bead geometry by synchronizing robotic weave cycles with desired pulsed waveform shapes to develop process parameters relationships and optimized pulsed gas metal arc welding processes for welding fatique-critical structures of steel, high strength steel, and aluminum. Quality would be addressed by developing intelligent methods of weld measurement that accurately predict weld bead geometry from process information. This program was severely underfunded, and eventually terminated. The scope was redirected to investigate tandem narrow groove welding of steel butt joints during the one year of partial funding. A torch was designed and configured to perform a design of experiments of steel butt weld joints that validated the feasability of the process. An initial cost model estimated a 60% cost savings over conventional groove welding by eliminating the joint preparation and reducing the weld volume needed.

Egland, Keith; Ludewig, Howard

2006-05-25

461

Laser-roll welding of a dissimilar metal joint of low carbon steel to aluminium alloy using 2 kW fibre laser  

Microsoft Academic Search

Recently, lightening, speed-up and decreasing vibration of the transport vehicles have been discussed for improving of environmental problems. As one solution, the material hybrid concept using aluminum alloys and high strength steels has been proposed. Therefore, new welding processes by which these dissimilar materials can be joined in high reliability and productivity are demanded. Laser roll welding was developed for

Hitoshi Ozaki; Muneharu Kutsuna

2009-01-01

462

Welding of titanium alloy by Disk laser  

NASA Astrophysics Data System (ADS)

The following article describes results of investigations on influence of laser welding parameters on the weld shape, quality and mechanical properties of 2.0 mm thick butt joints of titanium alloy Ti6Al4V (Grade 5 according to ASTM B265) welded with a new generation disk laser TRUMPF TRUDISK 3302, emitting at 1030 nm, with maximum output power 3300 W at circular laser beam spot, characterized by laser beam divergence 8.0 mm•mrad. The test butt joints of Ti6Al4V titanium alloy sheets were prepared as single square groove (I-type joint) and one-side laser welded without an additional material, at a flat position, using a specially designed system for shielding gas (purity 99.999%). The investigations at the initial stage were focused on detailed analysis of influence of the basic laser welding parameters such as laser power and welding speed on the shape and quality of single bead produced during bead-on-plate welding. Then the optimal parameters were chosen for laser welding of 2.0 mm thick butt joints of the titanium alloy Ti6Al4V. Edges of the titanium alloy sheets were melted in argon atmosphere by the laser beam focused on the top surface of butt joints. The test welded joints were investigated by visual inspection, metallographic examinations, hardness and micro-hardness measurements and mechanical tests such as tensile tests and bending tests. It was found that the welding mode is a keyhole welding and providing high quality of joints requires a special techniques and conditions of laser welding, as well as special gas shielding nozzles is required.

Lisiecki, Aleksander

2013-01-01

463

Fiber laser welding of nickel based superalloy Inconel 625  

NASA Astrophysics Data System (ADS)

The paper describes the application of single mode high power fiber laser (HPFL) for the welding of nickel based superalloy Inconel 625. Butt joints of Inconel 625 sheets 0,8 mm thick were laser welded without an additional material. The influence of laser welding parameters on weld quality and mechanical properties of test joints was studied. The quality and mechanical properties of the joints were determined by means of tensile and bending tests, and micro hardness tests, and also metallographic examinations. The results showed that a proper selection of laser welding parameters provides non-porous, fully-penetrated welds with the aspect ratio up to 2.0. The minimum heat input required to achieve full penetration butt welded joints with no defect was found to be 6 J/mm. The yield strength and ultimate tensile strength of the joints are essentially equivalent to that for the base material.

Janicki, Damian M.

2013-01-01

464

Joint Variability of Airborne Passive Microwave and Ground-based Radar Observations Obtained in the TRMM Kwajalein Experiment  

Microsoft Academic Search

The Tropical Rainfall Measuring Mission (TRMM) Kwajalein Experiment (KWAJEX) held July-September 1999 in the west Pacific was designed to obtain an empirical physical characterization of precipitating convective clouds over the tropical ocean. The majority of the precipitation was from mixed-phase clouds. Coordinated data sets were obtained from aircraft and ground-based sensors including passive microwave measurements by the Advanced Microwave Precipitation

S. E. Yuter; D. E. Kingsmill

2007-01-01

465

Preventing weld hot cracking by synchronous rolling during welding  

SciTech Connect

Based on the mechanical point of view of hot cracking in weldments, a new method, accomplished by synchronous rolling during welding (SRDW) along both sides of the weld at a suitable distance behind the welding arc, has been developed for preventing weld hot cracking. The theory behind this method was also examined. Three-dimensional simulative computations of displacement and strain fields produced by SRDW were carried out by means of the finite element method to reveal the mechanism of the new method and provide a theoretical basis for parameter choice. With a specially developed equipment for welding and synchronous rolling, experiments were performed to investigate the effectiveness and feasibility of this method in preventing weld hot cracking in high-strength aluminum alloy 2024-T4. Results show that weld hot cracking in 2024-Al alloy can be effectively prevented and the mechanical properties of welded joints can also be improved by the new method. It is an important new solution to weld hot cracking in welding of sheet metals.

Liu, W. [Dalian Railway Inst. (China). Dept. of Materials Science and Engineering; Tian, X.; Zhang, X. [School of Materials Science and Engineering, Harbin (China)

1996-09-01

466

Effects of conventional welding and laser welding on the tensile strength, ultimate tensile strength and surface characteristics of two cobalt-chromium alloys: a comparative study.  

PubMed

The purpose of this study was to evaluate the efficacy of laser welding and conventional welding on the tensile strength and ultimate tensile strength of the cobalt-chromium alloy. Samples were prepared with two commercially available cobalt-chromium alloys (Wironium plus and Diadur alloy). The samples were sectioned and the broken fragments were joined using Conventional and Laser welding techniques. The welded joints were subjected to tensile and ultimate tensile strength testing; and scanning electron microscope to evaluate the surface characteristics at the welded site. Both on laser welding as well as on conventional welding technique, Diadur alloy samples showed lesser values when tested for tensile and ultimate tensile strength when compared to Wironium alloy samples. Under the scanning electron microscope, the laser welded joints show uniform welding and continuous molt pool all over the surface with less porosity than the conventionally welded joints. Laser welding is an advantageous method of connecting or repairing cast metal prosthetic frameworks. PMID:23858281

Madhan Kumar, Seenivasan; Sethumadhava, Jayesh Raghavendra; Anand Kumar, Vaidyanathan; Manita, Grover

2012-04-18

467

Welding IV.  

ERIC Educational Resources Information Center

|Instructional objectives and performance requirements are outlined in this course guide for Welding IV, a competency-based course in advanced arc welding offered at the Community College of Allegheny County to provide students with proficiency in: (1) single vee groove welding using code specifications established by the American Welding Society…

Allegheny County Community Coll., Pittsburgh, PA.

468

Welding Curriculum.  

ERIC Educational Resources Information Center

|This competency-based curriculum guide is a handbook for the development of welding trade programs. Based on a survey of Alaskan welding employers, it includes all competencies a student should acquire in such a welding program. The handbook stresses the importance of understanding the principles associated with the various elements of welding

Alaska State Dept. of Education, Juneau. Div. of Adult and Vocational Education.

469

Analysis Method of Friction Torque and Weld Interface Temperature during Friction Process of Steel Friction Welding  

NASA Astrophysics Data System (ADS)

This paper describes an analysis method of the friction torque and weld interface temperature during the friction process for steel friction welding. The joining mechanism model of the friction welding for the wear and seizure stages was constructed from the actual joining phenomena that were obtained by the experiment. The non-steady two-dimensional heat transfer analysis for the friction process was carried out by calculation with FEM code ANSYS. The contact pressure, heat generation quantity, and friction torque during the wear stage were calculated using the coefficient of friction, which was considered as the constant value. The thermal stress was included in the contact pressure. On the other hand, those values during the seizure stage were calculated by introducing the coefficient of seizure, which depended on the seizure temperature. The relationship between the seizure temperature and the relative speed at the weld interface in the seizure stage was determined using the experimental results. In addition, the contact pressure and heat generation quantity, which depended on the relative speed of the weld interface, were solved by taking the friction pressure, the relative speed and the yield strength of the base material into the computational conditions. The calculated friction torque and weld interface temperatures of a low carbon steel joint were equal to the experimental results when friction pressures were 30 and 90 MPa, friction speed was 27.5 s-1, and weld interface diameter was 12 mm. The calculation results of the initial peak torque and the elapsed time for initial peak torque were also equal to the experimental results under the same conditions. Furthermore, the calculation results of the initial peak torque and the elapsed time for initial peak torque at various friction pressures were equal to the experimental results.

Kimura, Masaaki; Inoue, Haruo; Kusaka, Masahiro; Kaizu, Koichi; Fuji, Akiyoshi

470

Robotic Arc Welding: Research in Sensory Feedback Control  

Microsoft Academic Search

Robotic arc welding and its dependence on sensory feed-back control for successful application is discussed. Problems unique to arc weld sensing are identified and sensor requirements are categorized as a function of welding design requirements, joint imperfections, weld shape deviations, and process characteristics. The two most prevalent approaches of weld sensing, i.e., optical and through-the arc sensing, are covered.

George E. Cook

1983-01-01

471

Fatigue life of friction stir welded Al-Mg alloys  

Microsoft Academic Search

The following alloys EN- AW 5058 H321 and EN-AW 5059 H321 (Alustar) were welded by FSW (friction stir welding) method. The FSW welds showed better properties in comparison to the joints welded by the MIG method. The low-cycle fatigue life test was carried out in the symmetric cycle: in air and in 3.5% NaCl. Fatigue life of 5083 alloy welded

M. Czechowski

472

Study of a hybrid joining method using TIG welding: Aluminium alloy (Report 2)  

Microsoft Academic Search

The hybrid joining method has been proposed as a joining method which can be applied to the high precision assembly of thin sheet products. It has been confirmed that good joining results with 2–6 mm thick steel can be obtained consistently using this joining method.In this report, the plug joint and the hybrid joint welding of 1–6 mm thick aluminium

K. Yasuda; Y. Ishizawa; I. Kitaura

1998-01-01

473

kinITC: a new method for obtaining joint thermodynamic and kinetic data by isothermal titration calorimetry.  

PubMed

Isothermal titration calorimetry (ITC) is the method of choice for obtaining thermodynamic data on a great variety of systems. Here we show that modern ITC apparatus and new processing methods allow researchers to obtain a complete kinetic description of systems more diverse than previously thought, ranging from simple ligand binding to complex RNA folding. We illustrate these new features with a simple case (HIV-1 reverse transcriptase/inhibitor interaction) and with the more complex case of the folding of a riboswitch triggered by the binding of its ligand. The originality of the new kinITC method lies in its ability to dissect, both thermodynamically and kinetically, the two components: primary ligand binding and subsequent RNA folding. We are not aware of another single method that can yield, in a simple way, such deep insight into a composite process. Our study also rationalizes common observations from daily ITC use. PMID:22126339

Burnouf, Dominique; Ennifar, Eric; Guedich, Sondes; Puffer, Barbara; Hoffmann, Guillaume; Bec, Guillaume; Disdier, François; Baltzinger, Mireille; Dumas, Philippe

2011-12-16

474

Diode laser welding of aluminum to steel  

NASA Astrophysics Data System (ADS)

Laser welding of dissimilar materials was carried out by using a high power diode laser to join aluminum to steel in a butt-joint configuration. During testing, the laser scan rate was changed as well as the laser power: at low values of fluence (i.e. the ratio between laser power and scan rate), poor joining was observed; instead at high values of fluence, an excess in the material melting affected the joint integrity. Between these limiting values, a good aesthetics was obtained; further investigations were carried out by means of tensile tests and SEM analyses. Unfortunately, a brittle behavior was observed for all the joints and a maximum rupture stress about 40 MPa was measured. Apart from the formation of intermeltallic phases, poor mechanical performances also depended on the chosen joining configuration, particularly because of the thickness reduction of the seam in comparison with the base material.

Santo, Loredana; Quadrini, Fabrizio; Trovalusci, Federica

2011-05-01

475

Human bones obtained from routine joint replacement surgery as a tool for studies of plutonium, americium and ??Sr body-burden in general public.  

PubMed

The paper presents a new sampling method for studying in-body radioactive contamination by bone-seeking radionuclides such as (90)Sr, (239+240)Pu, (238)Pu, (241)Am and selected gamma-emitters, in human bones. The presented results were obtained for samples retrieved from routine surgeries, namely knee or hip joints replacements with implants, performed on individuals from Southern Poland. This allowed to collect representative sets of general public samples. The applied analytical radiochemical procedure for bone matrix is described in details. Due to low concentrations of (238)Pu the ratio of Pu isotopes which might be used for Pu source identification is obtained only as upper limits other then global fallout (for example Chernobyl) origin of Pu. Calculated concentrations of radioisotopes are comparable to the existing data from post-mortem studies on human bones retrieved from autopsy or exhumations. Human bones removed during knee or hip joint surgery provide a simple and ethical way for obtaining samples for plutonium, americium and (90)Sr in-body contamination studies in general public. PMID:21420209

Mietelski, Jerzy W; Golec, Edward B; Tomankiewicz, Ewa; Golec, Joanna; Nowak, Sebastian; Szczygiel, El?bieta; Brudecki, Kamil

2011-03-21

476

Stress analysis of a crack in the residual stress field by welding and its application to the fatigue crack propagation  

NASA Astrophysics Data System (ADS)

Structural failures often originate from weld joints. This is mainly due to metallurgical deterioration by heating, high likelihood of defects and residual stress by welding. In such a situation, it seems to be very important to study the behavior of a crack around the welded joint. In this paper, an analytical study of a crack perpendicular to the welding bead subjected to the residual stress was carried out using a stress function. At first, the conditions which should be satisfied for the residual stress by welding were examined. Then the simulation function satisfying these conditions was proposed. Next, the stress intensity factors of an arbitrary crack perpendicular to the butt weld, which was subjected to the effect of residual stress most severely, were derived by using the proposed function. The redistribution form of the residual stress near the crack was also evaluated and compared with the testing results obtained by Kanazawa, et al. Finally, the following effective stress intensity factor range delta K(sub eff), instead of the conventional delta K, was proposed to evaluate the effect of residual stress on the fatigue crack propagation of a crack. Delta K(sub eff) = delta K(1 plus K(sub res) divided by delta K) where, K(sub res) is the stress intensity factor induced by residual stress by welding. The effectiveness of delta K(sub eff) was proved by examining the experimental fatigue crack propagation data obtained by Glinka.

Terada, Hiroyuki

1994-09-01

477

Stress analysis of a crack in the residual stress field by welding and its application to the fatigue crack propagation  

NASA Astrophysics Data System (ADS)

Structural failures often originate from weld joints. This is mainly due to metallurgical deterioration by heating, high feasibility of defects and residual stress by welding. In such a situation, it seems to be very important to study the behavior of a crack around the welded joint. In this paper, an analytical study of a crack perpendicular to the welding bead subjected to the residual stress was carried out using a stress function. At first, the conditions which should be satisfied for the residual stress by welding were examined. Then the simulation function satisfying these conditions was proposed. Next, the stress intensity factors of an arbitrary crack perpendicular to the butt weld, which was subjected to the effect of residual stress, were derived by using the proposed function. The redistribution form of the residual stress near the crack was also evaluated and compared with the testing results obtained by Kanazawa, et al. Finally, the following effective stress intensity factor range delta K(sub eff), instead of conventional delta K, was proposed to evaluate the effect of residual stress on the fatigue crack propagation of a crack. Delta K(sub eff) = delta K(1 + (K(sub res)/delta K)), where, K(sub res) is the stress intensity factor induced by residual stress of welding. The effectiveness of delta K(sub eff) was proven by examining the experimental fatigue crack propagation data obtained by Glinka.

Terada, Hiroyuki

1994-09-01

478

Advances in welding science - a perspective  

SciTech Connect

The ultimate goal of welding technology is to improve the joint integrity and increase productivity. Over the years, welding has been more of an art than a science, but in the last few decades major advances have taken place in welding science and technology. With the development of new methodologies at the crossroads of basic and applied sciences, enormous opportunities and potential exist to develop a science-based tailoring of composition, structure, and properties of welds with intelligent control and automation of the welding processes.

David, S.A.; Vitek, J.M. [Oak Ridge National Lab., TN (United States); Babu, S.S.; DebRoy, T. [Pennsylvania State Univ., University Park, PA (United States)

1995-02-01

479

Optimization of weld bead geometry in laser welding with filler wire process using Taguchi’s approach  

NASA Astrophysics Data System (ADS)

In the present work, laser welding with filler wire was successfully applied to joining a new-type Al-Mg alloy. Welding parameters of laser power, welding speed and wire feed rate were carefully selected with the objective of producing a weld joint with the minimum weld bead width and the fusion zone area. Taguchi approach was used as a statistical design of experimental technique for optimizing the selected welding parameters. From the experimental results, it is found that the effect of welding parameters on the welding quality decreased in the order of welding speed, wire feed rate, and laser power. The optimal combination of welding parameters is the laser power of 2.4 kW, welding speed of 3 m/min and the wire feed rate of 2 m/min. Verification experiments have also been conducted to validate the optimized parameters.

dongxia, Yang; xiaoyan, Li; dingyong, He; zuoren, Nie; hui, Huang

2012-10-01

480

Effect of welding parameters on high-power diode laser welding on thin sheet  

NASA Astrophysics Data System (ADS)

High power diode laser (HPDL) is the newest laser tool for industrial manufacturing. The most promising areas of application of HPDL are thin sheet welding and hardening. The HPDL has several advantages and disadvantages compared to lasers CO2 and Nd:YAG lasers currently used for welding. There is quite a few industrial applications in which diode laser is the most suitable laser. A typical industrial installation consists of a HPDL, an industrial robot, work piece manipulation and safety enclosures. The HPDL welding process is at this moment conduction limited and has therefore different parameters than the keyhole welding. In this study the basic HPDL welding parameters and the effect of the parameters on the welding process, weld quality and efficiency are examined. Joint types tested are butt joint and fillet lap joint. The parameters tested are beam intensity, welding speed, spot size, beam impingement angle. The materials tested are common carbon steel and stainless steel. By the experiments carried out it can be seen that all of these parameters have an effect on the weld quality and the absorption of the laser power during welding. The higher the beam intensity is the shorter also the throughput time is. However, in case of fillet joint the maximum welding speed and best visual out look are achieved with totally different set of parameters. Based on these experiments it can, however, be seen that reliable welding parameters can be established for the welding of various industrial products. The beam quality of the diode laser is not optimum for high speed keyhole welding but it is a flexible tool to be used for different joint types.

Salminen, Antti; Jansson, Anssi; Kujanpää, Veli

2003-06-01

481

Laser welding of titanium in dentistry.  

PubMed

Unalloyed titanium of the quality used for osseointegrated implants by the method of Brånemark is also sometimes used for the metallic part of the prosthetic superstructure placed on the fixtures and for crowns and bridges of conventional type. Forty bars of titanium, 8 of ASTM B 348 grade-1 quality and 32 of ASTM B 348 grade-2 quality, were laser-welded, using dissimilar laser joint variables. Tensile strength, 0.2% proof stress, and percentage elongation of the welded bars were measured and compared with the corresponding values for the titanium bars as delivered and with those of brazed type-3 gold alloy bars of similar dimensions. The type of fracture was evaluated from fractographs. The results showed that the use of certain defined laser joint variables during welding produced values for the mechanical properties studied which were more favorable than those obtained from the brazed gold bars. The fracture of the titanium specimens was ductile, with dimples occurring at the fracture surfaces. PMID:2903608

Sjögren, G; Andersson, M; Bergman, M

1988-08-01

482

Role of welding parameters in determining the geometrical appearance of weld pool  

Microsoft Academic Search

A three-dimensional numerical model is developed to describe the fluid flow and heat transfer in weld pools. Both full penetration and free deformation of the top and bottom weld pool surfaces are considered. Temperature distribution and fluid flow field are obtained. In order to analyze the influence of welding parameters on the geometrical appearance of weld pools, a normalized model

R. Kovacevic; Z. N. Cao; Y. M. Zhang

1996-01-01

483

Sensing and control of weld pool by fuzzy-neural network in robotic welding system  

Microsoft Academic Search

It is important to control the penetration depth of the weld pool during welding, so as to obtain a good-quality weld, but it may be difficult to detect the penetration depth directly by using a visual sensor. In order to detect the penetration depth, the authors propose a penetration depth model based on a neural network. During welding, a fuzzy

A. Hirai; Y. Kaneko; T. Hosoda; S. Yamane; K. Oshima

2001-01-01

484

A Study on the Welding Characteristics of Tailor Welded Blank Metal Sheets Using GTAW and Laser Welding  

NASA Astrophysics Data System (ADS)

In this study, a computational and experimental effort was carried out to qualitatively understand the weld pool shape, distortion and residual stress for continuous laser welding and manual pulsed gas metal arc welding. For all the welding simulations given in this dissertation, a welding specific finite element package, SYSWELD, is used. This research focuses on the welding behavior observed in light-weight metal structures known as the tailor-welded blanks, TWBs. They are a combination of two or more metal sheets with different thickness and/or different materials that are welded together in a single plane prior to forming, e.g., stamping. They made from the low carbon steel. As laser welding experiment results show, the weld pool shape at the top and bottom surface, is strongly influenced by surface tension, giving it a characteristic hourglass shape. In order to simulate the hourglass shape, a new volumetric heat source model was developed to predict the transient temperature profile and weld pool shape, including the effect of surface tension. Tailor welded blanks with different thicknesses were examined in the laser welding process. All major physical phenomena such as thermal conduction, heat radiation and convection heat losses are taken into account in the model development as well as temperature-dependant thermal and mechanical material properties. The model is validated for the case of butt joint welding of cold rolled steel sheets. The results of the numerical simulations provide temperature distributions representing the shape of the molten pool, distortion and residual stress with varying laser beam power and welding speed. It is demonstrated that the finite element simulation results are in good agreement with the experiment results. This includes the weld pool shape and sheet metal distortion. While there is no experimental data to compare directly with residual stress results, the distorted shape provides an indirect measure of the welding residual stresses. The welding details such as clamping, butt joint configuration, material, sample thickness are similar for both the laser welding process and the manual pulsed GTAW process. Also as same metallurgical investigation, the weld pool shape displays wider full penetration without the effect of surface tension. The double ellipsoid volumetric heat source is applied in the finite element simulation to determine the temperature distribution, distortion and residual stress. The simulation results are compared with the experimental results and show good agreement. In addition, the results from the laser welding process are compared to the equivalent results from the GTAW process in the order to better understand the fundamental differences between these two welding processes.

Thasanaraphan, Pornsak

485

MATERIAL AND STRUCTURAL BEHAVIOUR OF MIG BUTT WELDS IN 6000 SERIES ALUMINIUM ALLOY EXTRUSIONS FOR RAIL VEHICLES  

Microsoft Academic Search

The welding of 6000 series aluminium alloys can have potentially adverse effects on the material and structural behaviour of the welded joints. In recent accidents involving welded aluminium rail vehicles, some of the longitudinal welds fractured for some metres beyond the zones of severe damage. MIG welding is the main process employed today in the UK and Europe for joining

W Xu; M F Gittos

486

Low-cycle fatigue of friction stir welded Al–Mg alloys  

Microsoft Academic Search

The following alloys EN-AW 5058 H321 and EN-AW 5059 H321 (Alustar) were welded by FSW (friction stir welding) method. The FSW welds showed better properties in comparison to the joints welded by the MIG method. The test of microstructure proved the proper structure of the weld which consisted of following: welded nugget, thermo-mechanically affected zone (TMAZ), heat affected zone (HAZ)

M. Czechowski

2005-01-01

487

Simplified inelastic analysis procedure to evaluate a butt-welded elbow end  

SciTech Connect

In a thin-walled piping network, the end of an elbow welded to a straignt pipe constitutes one of the highly stressed cross-sections that require structural evaluation. Explicit rules are not provided in the ASME Code for structural evaluation of the elbow ovalization and fabrication effects at the welded end. This paper presents a conservative semi-analytical procedure that can be used with simplified inelastic analysis to evaluate the elbow cross section welded to the straight pipe. The concept of carry-over factors is used to obtain ovalization stresses or strains at the elbow end. The stresses introduced by material and geometric nonuniformities in the fabrication process are then added to the ovalization stresses to complete structural evluation of the girth butt-welded elbow joint.

Dhalla, A.K.

1981-01-01

488

The synchronized tandem wire welding process applied to the welding of structural plates  

Microsoft Academic Search

As part of a European research project, partially funded by the Steel Research Fund (RFS-CR-03049), the potential benefits derived from the use of synchronized tandem wire welding (STW) technology applied to structural plates, in place of the currently used arc techniques, have been evaluated.In particular, two welded joint types have been investigated: T joints and butt joints in S355 grade

V. Fersini; S. Matera

2009-01-01

489