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Sample records for welded shear-lab specimens

  1. 3D modelling of plug failure in resistance spot welded shear-lab specimens (DP600-steel)

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    2008-01-01

    are based on uni-axial tensile testing of the basis material, while the modelled tensile response of the shear-lab specimens is compared to experimental results for the case of a ductile failure near the heat affected zone (HAZ). A parametric study for a range of weld diameters is carried out, which makes......Ductile plug failure of resistance spot welded shear-lab specimens is studied by full 3D finite element analysis, using an elastic-viscoplastic constitutive relation that accounts for nucleation and growth of microvoids to coalescence (The Gurson model). Tensile properties and damage parameters...... it possible to numerically relate the weld diameter to the tensile shear force (TSF) and the associated displacement, u (TSF) , respectively. Main focus in the paper is on modelling the localization of plastic flow and the corresponding damage development in the vicinity of the spot weld, near the HAZ...

  2. Ultrasonic Evaluation of Two Dissimilar Metal Weld Overlay Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Susan L.; Cinson, Anthony D.; Prowant, Matthew S.; Moran, Traci L.; Anderson, Michael T.

    2012-06-30

    Two dissimilar metal weld (DMW) pipe-to-nozzle specimens were implanted with thermal fatigue cracks in the 13% to 90% through-wall depth range. The specimens were ultrasonically evaluated with phased-array probes having center frequencies of 0.8, 1.0, 1.5, and 2.0 megahertz (MHz). An Alloy 82/182 weld overlay (WOL) was applied and the specimens were ultrasonically re-evaluated for flaw detection and characterization. The Post-WOL flaw depths were approximately 10% to 56% through-wall. This study has shown the effectiveness of ultrasonic examinations of Alloy 82/182 overlaid DMW specimens. Phased-array probes with center frequency in the 0.8- to 1.0-MHz range provide a strong coherent signal but the greater ultrasonic wavelength and larger beam spot size prevent the reliable detection of small flaws. These small flaws had nominal through-wall depths of less than 15% and length in the 50-60 mm (2-2.4 in.) range. Flaws in the 19% and greater through-wall depth range were readily detected with all four probes. At the higher frequencies, the reflected signals are less coherent but still provide adequate signal for flaw detection and characterization. A single inspection at 2.0 MHz could provide adequate detection and sizing information but a supplemental inspection at 1.0 or 1.5 MHz is recommended.

  3. Characteristics of coated copper wire specimens using high frequency ultrasonic complex vibration welding equipments.

    Science.gov (United States)

    Tsujino, J; Ihara, S; Harada, Y; Kasahara, K; Sakamaki, N

    2004-04-01

    Welding characteristic of thin coated copper wires were studied using 40, 60, 100 kHz ultrasonic complex vibration welding equipments with elliptical to circular vibration locus. The complex vibration systems consisted of a longitudinal-torsional vibration converter and a driving longitudinal vibration system. Polyurethane coated copper wires of 0.036 mm outer diameter and copper plates of 0.3 mm thickness and the other dimension wires were used as welding specimens. The copper wire part is completely welded on the copper substrate and the insulated coating material is driven from welded area to outsides of the wire specimens by high frequency complex vibration.

  4. 3D analyses of the effect of weld orientation in Charpy specimens

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, A.

    2004-01-01

    of failure in the weld material, base material and heat affected zone (HAZ). For these rotated specimens the location where the notch crosses the thin layer of HAZ, i.e. whether this location is near the center of the specimen or near the free specimen edge, makes a large difference in the response. (C) 2004...

  5. Experimental investigation of the thickness effect for large as-welded SAW S355 steel specimens

    DEFF Research Database (Denmark)

    Ólafsson, Ólafur Magnús; Jensen, Jørgen Juncher; Berggreen, Christian

    2016-01-01

    The presented work aims to investigate and establish a pre-cise, thorough and detailed database from series of experi-mental testing of submerged arc welded (SAW) specimens of various thicknesses typically applied in ships and offshore structures and foundations. Welded structures of all sizes...

  6. Weld investigations by 3D analyses of Charpy V-notch specimens

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, Allan

    2005-01-01

    The Charpy impact test is a standard procedure for determining the ductile-brittle transition in welds. The predictions of such tests have been investigated by full three dimensional transient analyses of Charpy V-notch specimens. The material response is characterised by an elastic-viscoplastic ......The Charpy impact test is a standard procedure for determining the ductile-brittle transition in welds. The predictions of such tests have been investigated by full three dimensional transient analyses of Charpy V-notch specimens. The material response is characterised by an elastic...... parameters in the weld material differ from those in the base material, and the heat a®ected zone (HAZ) tends to be more brittle than the other material regions. The effect of weld strength undermatch or overmatch is an important issue. Some specimens, for which the notched surface is rotated relative...

  7. Experimental study on variations in Charpy impact energies of low carbon steel, depending on welding and specimen cutting method

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhaorui; Kang, Hansaem; Lee, Young Seog [Chung-Ang University, Seoul (Korea, Republic of)

    2016-05-15

    This paper presents an experimental study that examines variations of Charpy impact energy of a welded steel plate, depending upon the welding method and the method for obtaining the Charpy specimens. Flux cored arc welding (FCAW) and Gas tungsten arc welding (GTAW) were employed to weld an SA516 Gr. 70 steel plate. The methods of wire cutting and water-jet cutting were adopted to take samples from the welded plate. The samples were machined according to the recommendations of ASTM SEC. II SA370, in order to fit the specimen dimension that the Charpy impact test requires. An X-ray diffraction (XRD) method was used to measure the as-weld residual stress and its redistribution after the samples were cut. The Charpy impact energy of specimens was considerably dependent on the cutting methods and locations in the welded plate where the specimens were taken. The specimens that were cut by water jet followed by FCAW have the greatest resistance-to-fracture (Charpy impact energy). Regardless of which welding method was used, redistributed transverse residual stress becomes compressive when the specimens are prepared using water-jet cutting. Meanwhile, redistributed transverse residual stress becomes tensile when the specimens are prepared using wire cutting.

  8. Effect of Specimen Orientation on Fatigue Crack Growth Behavior in Friction Stir Welded Al7075-T651 Joints

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Yeui Han; Kim, Seon Jin [Pukyoung National University, Busan (Korea, Republic of)

    2014-12-15

    The aim of this paper is to investigate the effects of crack orientation on fatigue crack growth behavior in friction stir welded (FSWed) Al 7075-T651. Fatigue crack growth testing was conducted on compact tension (CT) specimens machined from the friction stir welds and the base metal under constant stress intensity factor range control. Tests were performed with the crack propagating nominally perpendicular to the weld line (termed the TL specimen) and the crack propagating in a parallel direction of the weld line (termed the LT specimen), and with three different constant stress intensity factor ranges. Both these specimen orientations were found to have a considerable effect on the fatigue crack growth behavior. Paris’s law was adopted for the analysis of experimental results; the exponent m of the WM-LT specimen was determined to be 3.56, which was the largest value in this experimental conditions.

  9. Automated Flaw Detection Scheme For Cast Austenitic Stainless Steel Weld Specimens Using Hilbert Huang Transform Of Ultrasonic Phased Array Data

    Energy Technology Data Exchange (ETDEWEB)

    Khan, T.; Majumdar, Shantanu; Udpa, L.; Ramuhalli, Pradeep; Crawford, Susan L.; Diaz, Aaron A.; Anderson, Michael T.

    2012-01-01

    The objective of this work is to develop processing algorithms to detect and localize the flaws using NDE ultrasonic data. Data was collected using cast austenitic stainless steel (CASS) weld specimens on-loan from the U.S. nuclear power industry’s Pressurized Water Reactor Owners Group (PWROG) specimen set. Each specimen consists of a centrifugally cast stainless steel (CCSS) pipe section welded to a statically cast (SCSS) or wrought (WRSS) section. The paper presents a novel automated flaw detection and localization scheme using low frequency ultrasonic phased array inspection signals in the weld and heat affected zone of the base materials. The major steps of the overall scheme are preprocessing and region of interest (ROI) detection followed by the Hilbert Huang transform (HHT) of A-scans in the detected ROIs. HHT offers time-frequency-energy distribution for each ROI. The accumulation of energy in a particular frequency band is used as a classification feature for the particular ROI.

  10. Evaluation on ductile tearing properties of girth weld pipelines using SE(T) and SE(B) specimens

    Energy Technology Data Exchange (ETDEWEB)

    Mathias, Leonardo Luiz Siqueira; Ruggieri, Claudio [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia Naval e Oceanica

    2012-07-01

    Predictive methodologies aimed at quantifying the impact of defects in oil and gas pipelines play a key role in safety assessment procedures of in-service facilities. Current methodologies for structural integrity assessments advocate the use of geometry dependent resistance curves so that crack-tip constraint in the test specimen closely matches the crack tip constraint for the structural component. Testing standards now under development to measure fracture resistance of pipeline steels (J and CTOD) most often employ single edge notched specimens under tension (SENT) to match a postulated defect in the structural component. This paper presents an investigation of the ductile tearing properties for a girth weld of an API 5L X80 pipeline steel using experimentally measured crack growth resistance curves (J-R curves). Testing of the girth weld pipeline steels employed side-grooved, clamped SE(T) specimen with center-crack weld and side-grooved, three-point bending SE(B) (or SENB) specimens to determine the J-R curves. The methods were compared in terms of geometry, relative crack size and crack-tip constraint, and the results were applied to a case study, to evaluate the degree of conservativeness in defect acceptance criteria. The tests involving SE(B) specimens are usually considered conservative, however, the comparison between this two methods may point an accurate alternative for girth weld assessments, since adequate geometry is adopted to describe accurately the structure's behavior. (author)

  11. Evaluation on ductile tearing properties of girth weld pipelines using SE(T) and SE(B) specimens

    Energy Technology Data Exchange (ETDEWEB)

    Mathias, Leonardo Luiz Siqueira; Ruggieri, Claudio [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia Naval e Oceanica

    2012-07-01

    Predictive methodologies aimed at quantifying the impact of defects in oil and gas pipelines play a key role in safety assessment procedures of in-service facilities. Current methodologies for structural integrity assessments advocate the use of geometry dependent resistance curves so that crack-tip constraint in the test specimen closely matches the crack tip constraint for the structural component. Testing standards now under development to measure fracture resistance of pipeline steels (J and CTOD) most often employ single edge notched specimens under tension (SENT) to match a postulated defect in the structural component. This paper presents an investigation of the ductile tearing properties for a girth weld of an API 5L X80 pipeline steel using experimentally measured crack growth resistance curves (J-R curves). Testing of the girth weld pipeline steels employed side-grooved, clamped SE(T) specimen with center-crack weld and side-grooved, three-point bending SE(B) (or SENB) specimens to determine the J-R curves. The methods were compared in terms of geometry, relative crack size and crack-tip constraint, and the results were applied to a case study, to evaluate the degree of conservativeness in defect acceptance criteria. The tests involving SE(B) specimens are usually considered conservative, however, the comparison between this two methods may point an accurate alternative for girth weld assessments, since adequate geometry is adopted to describe accurately the structure's behavior. (author)

  12. Influence of heat input on weld bead geometry using duplex stainless steel wire electrode on low alloy steel specimens

    Directory of Open Access Journals (Sweden)

    Ajit Mondal

    2016-12-01

    Full Text Available Gas metal arc welding cladding becomes a popular surfacing technique in many modern industries as it enhances effectively corrosion resistance property and wear resistance property of structural members. Quality of weld cladding may be enhanced by controlling process parameters. If bead formation is found acceptable, cladding is also expected to be good. Weld bead characteristics are often assessed by bead geometry, and it is mainly influenced by heat input. In this paper, duplex stainless steel E2209 T01 is deposited on E250 low alloy steel specimens with 100% CO2 gas as shielding medium with different heats. Weld bead width, height of reinforcement and depth of penetration are measured. Regression analysis is done on the basis of experimental data. Results reveal that within the range of bead-on-plate welding experiments done, parameters of welding geometry are on the whole linearly related with heat input. A condition corresponding to 0.744 kJ/mm heat input is recommended to be used for weld cladding in practice.

  13. Numerical Simulation and Experimental Verification of CMOD in SENT Specimen: Application on FCGR of Welded Tool Steel

    Institute of Scientific and Technical Information of China (English)

    Amir SULTAN; Riffat Asim PASHA; Mifrah ALI; Muhammad Zubair KHAN; Muhammad Afzal KHAN; Naeem Ullah DAR; Masood SHAH

    2013-01-01

    Single-edged notched tension (SENT) specimen is used to study the fatigue crack growth rate (FCGR) behavior of AISI 50100 steel using MTS 810.Calibration tests are run to get plots of crack mouth opening displacement (CMOD) vs.load and CMOD vs.crack length-to-width ratio with the known crack lengths.Numerical simulation is also done to try to establish a relation between crack length and CMOD.FCGR of welded and un-welded specimens are plotted against stress intensity factor range to show the effect of welding on fatigue crack growth rate of AISI 50100 steel.The experimentally obtained CMOD values are compared with values obtained by numerical simulation using ABAQUS/StandardTM software package.Results show that numerical values are in good agreement with experimental data for small crack lengths and lower values of applied load.

  14. Technique for the residual life assessment of high temperature components based on creep-rupture testing on welded miniature specimens

    Energy Technology Data Exchange (ETDEWEB)

    Garzillo, A.; Guardamagna, C.; Moscotti, L.; Ranzani, L. [Ente Nazionale per l`Energia Elettrica, Milan (Italy)

    1995-06-01

    Following the present trend in the development of advanced methodologies for residual life assessment of high temperature components operating in power plants, particularly in non destructive methods, a testing technique has been set up at ENEL-CRAM based on creep-rupture testa in an argon on welded miniature specimens. Five experimental systems for creep-rupture tests in an argon atmosphere have been set up which include high accuracy systems, vacuum chambers and exrwnsometer devices. With the aim of establishing and validating the suitability of the experimental methodology, creep-rupture and interrupted creep testing programmes have been performed on miniature specimens (2 mm diameter and 10 mm gauge lenght). On the basis of experience gathered by various European research laboratories, a miniature specimen construction procedure has been developed using a laser welding technique for joining threaded heads to sample material. Low alloy ferritic steels, such as virgin 2.25CrlMo, 0.5Cr 0.5Mo 0.25V, and IN 738 superalloy miniature specimens have been investigated and the results, compared with those from standard specimens, show a regular trend in deformation vs time. Additional efforts to provide guidelines for material sampling from each plant component will be required in order to reduce uncertainties in residual life prediction.

  15. Specimen Test of Large-Heat-Input Fusion Welding Method for Use of SM570TMCP

    Directory of Open Access Journals (Sweden)

    Dongkyu Lee

    2015-01-01

    Full Text Available In this research, the large-heat-input welding conditions optimized to use the rear plate and the high-performance steel of SM570TMCP, a new kind of steel suitable for the requirements of prospective customers, are proposed. The goal of this research is to contribute to securing the welding fabrication optimized to use the high-strength steel and rear steel plates in the field of construction industry in the future. This research is judged to contribute to securing the welding fabrication optimized to use the high-strength steel and rear steel plates in the field of construction industry in the future.

  16. Numerical Analysis of Crack Progress in Different Areas of a Friction Stir Welded Bead for an 5251 H14 Aluminum Alloy Specimen

    Directory of Open Access Journals (Sweden)

    Y. Kambouz

    2014-02-01

    Full Text Available The assemblies welded by Friction Stir Welding have a major advantage which is the absence of a metal filler. This process contributes to the welding of materials that are known to be difficult to weld using the conventional techniques often employed in the field of transport, for example in the automobile body by applying a spot welding. The numerical modeling of this type of process is complex, not only in terms of the variety of physical phenomena which must be considered, but also because of the experimental procedure that must be followed in order to verify and validate numerical predictions. In this work, a finite element model is proposed in order to simulate the crack propagation under monotonic loading in different areas of the weld seam of a strain hardening CT-50 aluminum alloy 5251H14 specimen.

  17. PVRC/MPC Round Robin Tests for the Low Toughness High-Copper 72W Weld Using Master Curve Methodology of PCVN Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bong-Sang; Hong, Jun Hwa; Yang, Won Jon

    2000-06-01

    This report summarizes the results obtained from the Korean contribution the PVRC/MPC cooperative program on {sup R}ound Robin Tests for Low Toughness High-Copper 72W Weld Using Master Curve Methodology of PCVN Specimens. The mandatory part of this program is to perform fracture toughness (K{sub jc}) tests on the low toughness 72W weld at three different temperatures using pre-cracked Charpy specimens. The purpose of the tests is to verify the specimen size requirements in the ASTM E 1921, 'Standard test method for determination of reference temperature, T{sub o}, for ferritic steels in the transition range'.

  18. Measurement and prediction of residual stress in a bead-on-plate weld benchmark specimen

    Energy Technology Data Exchange (ETDEWEB)

    Ficquet, X.; Smith, D.J. [Department of Mechanical Engineering, University of Bristol, Queen' s Building, University Walk, Bristol BS8 1TR (United Kingdom); Truman, C.E. [Department of Mechanical Engineering, University of Bristol, Queen' s Building, University Walk, Bristol BS8 1TR (United Kingdom)], E-mail: c.e.truman@bristol.ac.uk; Kingston, E.J. [Veqter Ltd, University Gate East, Park Row, Bristol BS1 5UB (United Kingdom); Dennis, R.J. [Frazer-Nash Consultancy Limited, 1 Trinity Street, College Green, Bristol BS1 5TE (United Kingdom)

    2009-01-15

    This paper presents measurements and predictions of the residual stresses generated by laying a single weld bead on a flat, austenitic stainless steel plate. The residual stress field that is created is strongly three-dimensional and is considered representative of that found in a repair weld. Through-thickness measurements are made using the deep hole drilling technique, and near-surface measurements are made using incremental centre hole drilling. Measurements are compared to predictions at the same locations made using finite element analysis incorporating an advanced, non-linear kinematic hardening model. The work was conducted as part of an European round robin exercise, coordinated as part of the NeT network. Overall, there was broad agreement between measurements and predictions, but there were notable differences.

  19. Impact energy analysis of HSLA specimens after simulated welding thermal cycle

    Directory of Open Access Journals (Sweden)

    Samarždić, I.

    2008-04-01

    Full Text Available This paper presents impact energy results of specimens made from high strength fine grained steel TStE 420 after thermal cycle simulation. These results are obtained by examining Charpy specimens. Metallographic analysis is performed, hardness is measured and total impact energy is divided into ductile and brittle components.

  20. Ductile shear failure or plug failure of spot welds modelled by modified Gurson model

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Tvergaard, Viggo

    2010-01-01

    For resistance spot welded shear-lab specimens, interfacial failure under ductile shearing or ductile plug failure are analyzed numerically, using a shear modified Gurson model. The interfacial shear failure occurs under very low stress triaxiality, where the original Gurson model would predict...... void nucleation and very limited void growth. Void coalescence would therefore be largely postponed. However, using the shear modification of the Gurson model, recently introduced by Nahshon and Hutchinson (2008) [1], failure prediction is possible at zero or even negative mean stress. Since......, this shear modification has too large effect in some cases where the stress triaxiality is rather high, an extension is proposed in the present study to better represent the damage development at moderate to high stress triaxiality, which is known to be well described by the Gurson model. Failure prediction...

  1. Predicting failure response of spot welded joints using recent extensions to the Gurson model

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    2010-01-01

    The plug failure modes of resistance spot welded shear-lab and cross-tension test specimens are studied, using recent extensions to the Gurson model. A comparison of the predicted mechanical response is presented when using either: (i) the Gurson-Tvergaard-Needleman model (GTN-model), (ii......) the shear-modified GTN-model by Nahshon and Hutchinson that also describes damage development at low triaxiality (NH-model) or (iii) the Gologanu-Leblond-Devaux model (GLD-model) accounting for non-spherical void growth. The failure responses predicted by the various models are discussed in relation...... to their approximate description of the nucleation, growth and coalescence of microvoids. Using the void shape factor of the GLD-model, a simple approach for approximating void nucleation by either particle fracture or particle-matrix decohesion is applied and a study of the subsequent void shape evolution...

  2. Weld examination on tube test specimen using TOFD; Untersuchungen mit TOFD an geschweissten Laengsnahtproben

    Energy Technology Data Exchange (ETDEWEB)

    Brekow, G.; Erhard, A. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany). Labor fuer Ultraschallverfahren

    2000-07-01

    In contrast to the pulse echo technique, which is based on the sound field reflection at the flaw surface, the Time of Flight Diffraction (TOFD) technique uses the diffraction of the sound field at the flaw tips. For this purpose two angle beam probes for longitudinal waves are used in a pitch and catch arrangement. The transducers are positioned at both sides of the welding seam and are moved parallel to it during the measurement. The diffraction at the flaw tips causes different time of flight values with respect to the upper and lower flaw tip. Time dependent signals are stored in a series of A-scan pictures, which can finally be represented in a B-picture, which has to be interpreted. As investigations show there are additional useful information concerning defect size which can be given by TOFD, but pulse echo techniques with additional radiographic testing cannot be substituted by TOFD. (orig.) [German] Im Gegensatz zur Impuls-Echo-Technik, die im Wesentlichen auf der Reflexion am Fehler basiert, wird bei der Time-Of-Flight Diffraction Technique (TOFD-Technik) die Beugung der Schallwellen am Fehler zum Nachweis genutzt. Zwei Winkelpruefkoepfe fuer Longitudinalwellen sind in V-Durchschallung angeordnet. Die Pruefkoepfe befinden sich jeweils auf einer Seite der Schweissnaht und werden bei der Messung parallel zur Schweissnaht verschoben. Das ausgesandte Schallbuendel trifft auf Fehlerraender, an denen gebeugte Wellenanteile entstehen, die je nach Entstehungsort mit unterschiedlichen Schallaufzeiten empfangen, in hochfrequenten A-Bildern abgespeichert und fuer die Auswertung in B-Bildern dargestellt werden. Die Untersuchungen zeigen, dass die TOFD-Technik Beitraege zur Fehlergroessenabschaetzung liefert, aber keinesfalls die Impuls-Echo-Technik mit nachgeschalteter Roentgenpruefung ersetzen kann. (orig.)

  3. Mechanical Behavior of Lithium-Ion Batteries and Fatigue Behavior of Ultrasonic Weld-Bonded Lap-Shear Specimens of Dissimilar Magnesium and Steel Sheets

    Science.gov (United States)

    Lai, Wei-Jen

    The mechanical behaviors of LiFePO4 battery cell and module specimens under in-plane constrained compression were investigated for simulations of battery cells, modules and packs under crush conditions. The experimental stress-strain curves were correlated to the deformation patterns of battery cell and module specimens. Analytical solutions were developed to estimate the buckling stresses and to provide a theoretical basis for future design of representative volume element cell and module specimens. A physical kinematics model for formation of kinks and shear bands in battery cells was developed to explain the deformation mechanism for layered battery cells under in-plane constrained compression. A small-scale module constrained punch indentation test was also conducted to benchmark the computational results. The computational results indicate that macro homogenized material models can be used to simulate battery modules under crush conditions. Fatigue behavior and failure modes of ultrasonic spot welds in lap-shear specimens of magnesium and steel sheets with and without adhesive were investigated. For ultrasonic spot welded lap-shear specimens, the failure mode changes from the partial nugget pullout mode under low-cycle loading conditions to the kinked crack failure mode under high-cycle loading conditions. For adhesive-bonded and weld-bonded lap-shear specimens, the test results show the near interface cohesive failure mode and the kinked crack failure mode under low-cycle and high-cycle loading conditions, respectively. Next, the analytical effective stress intensity factor solutions for main cracks in lap-shear specimens of three dissimilar sheets under plane strain conditions were developed and the solutions agreed well with the computational results. The analytical effective stress intensity factor solutions for kinked cracks were compared with the computational results at small kink lengths. The results indicate that the computational results approach to

  4. Status Report on Irradiation Capsules Containing Welded FeCrAl Specimens for Radiation Tolerance Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-02-26

    This status report provides the background and current status of a series of irradiation capsules, or “rabbits”, that were designed and built to test the contributions of microstructure, composition, damage dose, and irradiation temperature on the radiation tolerance of candidate FeCrAl alloys being developed to have enhanced weldability and radiation tolerance. These rabbits will also test the validity of using an ultra-miniature tensile specimen to assess the mechanical properties of irradiated FeCrAl base metal and weldments. All rabbits are to be irradiated in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) to damage doses up to ≥15 dpa at temperatures between 200-550°C.

  5. Welding.

    Science.gov (United States)

    Cowan, Earl; And Others

    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…

  6. Influence of heat input on weld bead geometry using duplex stainless steel wire electrode on low alloy steel specimens

    OpenAIRE

    Ajit Mondal; Manas Kumar Saha; Ritesh Hazra; Santanu Das

    2016-01-01

    Gas metal arc welding cladding becomes a popular surfacing technique in many modern industries as it enhances effectively corrosion resistance property and wear resistance property of structural members. Quality of weld cladding may be enhanced by controlling process parameters. If bead formation is found acceptable, cladding is also expected to be good. Weld bead characteristics are often assessed by bead geometry, and it is mainly influenced by heat input. In this paper, duplex stainless st...

  7. Spatial Randomness of Fatigue Crack Growth Rate in Friction Stir Welded 7075-T111 Aluminum Alloy Welded Joints (Case of L T Orientation Specimen)

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Yeui Han; Kim, Seon Jin [Pukyong Nat' l Univ., Busan (Korea, Republic of)

    2013-09-15

    This study aims to investigate the spatial randomness of fatigue crack growth rate for the friction stir welded (FSWed) 7075-T111 aluminum alloy joints. Our previous fatigue crack growth test data are adopted in this investigation. To clearly understand the spatial randomness of fatigue crack growth rate, fatigue crack growth tests were conducted under constant stress intensity factor range (SEFOR) control testing. The experimental data were analyzed for two different materials-base metal (BM) and weld metal (WM)-to investigate the effects of spatial randomness of fatigue crack growth rate and material properties, the friction stir welded (FSWed) 7075-T111 aluminum alloy joints, namely weld metal (WM) and base metal (BM). The results showed that the variability, as evaluated by Wobble statistical analysis, of the WM is higher than that of the BM.

  8. Experimental Investigation of Fatigue Crack Growth Behavior in Friction Stir Welded 7075-T111 Aluminum Alloy Joints under Constant Stress Intensity Factor Range Control Testing (For L T Orientation Specimen)

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Yeui Han; Kim, Seon Jin [Pukyong Nat' l Univ., Busan (Korea, Republic of)

    2013-06-15

    In this study, as a series of studies aimed at investigating the spatial randomness of fatigue crack growth for friction stir welded (FSWed) 7075-T111 aluminum alloy joints, the fatigue crack growth behavior of FSWed 7075-T111 aluminum alloy joints was investigated for L T orientation specimens. Fatigue crack growth tests were conducted under constant stress intensity factor range (SEFOR) control for 5 specimens of the FSWed 7075-T111 aluminum alloy, including base metal (B M), heat affected zone (Haz), and weld metal (W M) specimens. The mean fatigue crack growth rate of W M specimens was found to be the highest, whereas that of Haz and W M specimens was the lowest. Furthermore, the variability of fatigue crack growth rate was found to be the highest in W M specimens and lowest in B M specimens.

  9. Modelling of damage development and ductile failure in welded joints

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    This thesis focuses on numerical analysis of damage development and ductile failure in welded joints. Two types of welds are investigated here. First, a study of the localization of plastic flow and failure in aluminum sheets, welded by the relatively new Friction Stir (FS) Welding method, has been...... conducted ([P1], [P2], [P7]-[P9]). The focus in the thesis is on FS-welded 2xxx and 6xxx series of aluminum alloys, which are attractive, for example, to the aerospace industry, since the 2024 aluminum in particular, is typically classified as un-weldable by conventional fusion welding techniques. Secondly......, a study of the damage development in Resistance SpotWelded joints, when subject to the commonly used static shear-lab or cross-tension testing techniques, has been carried out ([P3]-[P6]). The focus in thesis is on the Advanced High Strength Steels, Dual-Phase 600, which is used in for example...

  10. Impact energy analysis of quenched and tempered fine grain structural steel specimens after weld thermal cycle simulation

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2014-10-01

    Full Text Available The paper presents impact energy results of thermal cycle simulated specimens of quenched and tempered fine grain structural steel S960QL. These results are obtained by examining notched Charpy specimens. Upon performed metallographic analysis and measured hardness, total impact energy is separated into ductile and brittle components.

  11. Influence of heat treatments for laser welded semi solid metal cast A356 alloy on the fracture mode of tensile specimens

    CSIR Research Space (South Africa)

    Kunene, G

    2008-09-01

    Full Text Available . Sample Si Fe Cu Mn Mg Zn Ti Cr Sr Al A356 Literature Spec10 6.5 - 7.5 0.2 max. 0.20 max. 0.10 max. 0.25 - 0.45 0.10 max. 0.20 max. - - 0.30 max Bal. Virgin material 7.33 0.13 0.01 0.01 0... for Laser Welded Semi Solid Metal Cast A356 Alloy on the Fracture Mode of Tensile Specimens G. Kunene1, a, G. Govender1,b, L. Ivanchev1,c, R. Knutsen2,d and H. Burger3,e 1CSIR: Materials Science and Manufacturing, P.O. Box 395, Pretoria, 0001 South...

  12. Laser welding in space

    Science.gov (United States)

    Kaukler, W. F.; Workman, G. L.

    1991-01-01

    Autogenous welds in 304 stainless steel were performed by Nd-YAG laser heating in a simulated space environment. Simulation consists of welding on the NASA KC-135 aircraft to produce the microgravity and by containing the specimen in a vacuum chamber. Experimental results show that the microgravity welds are stronger, harder in the fusion zone, have deeper penetration and have a rougher surface rippling of the weld pool than one-g welds. To perform laser welding in space, a solar-pumped laser concept that significantly increases the laser conversion efficiency and makes welding viable despite the limited power availability of spacecraft is proposed.

  13. Biaxial Creep Specimen Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    JL Bump; RF Luther

    2006-02-09

    This report documents the results of the weld development and abbreviated weld qualification efforts performed by Pacific Northwest National Laboratory (PNNL) for refractory metal and superalloy biaxial creep specimens. Biaxial creep specimens were to be assembled, electron beam welded, laser-seal welded, and pressurized at PNNL for both in-pile (JOYO reactor, O-arai, Japan) and out-of-pile creep testing. The objective of this test campaign was to evaluate the creep behavior of primary cladding and structural alloys under consideration for the Prometheus space reactor. PNNL successfully developed electron beam weld parameters for six of these materials prior to the termination of the Naval Reactors program effort to deliver a space reactor for Project Prometheus. These materials were FS-85, ASTAR-811C, T-111, Alloy 617, Haynes 230, and Nirnonic PE16. Early termination of the NR space program precluded the development of laser welding parameters for post-pressurization seal weldments.

  14. Phased Array Ultrasonic Examination of Reactor Coolant System (Carbon Steel-to-CASS) Dissimilar Metal Weld Mockup Specimen

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, S. L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cinson, A. D. [US Nuclear Regulatory Commission (NRC), Washington, DC (United States); Diaz, A. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Anderson, M. T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-11-23

    In the summer of 2009, Pacific Northwest National Laboratory (PNNL) staff traveled to the Electric Power Research Institute (EPRI) NDE Center in Charlotte, North Carolina, to conduct phased-array ultrasonic testing on a large bore, reactor coolant pump nozzle-to-safe-end mockup. This mockup was fabricated by FlawTech, Inc. and the configuration originated from the Port St. Lucie nuclear power plant. These plants are Combustion Engineering-designed reactors. This mockup consists of a carbon steel elbow with stainless steel cladding joined to a cast austenitic stainless steel (CASS) safe-end with a dissimilar metal weld and is owned by Florida Power & Light. The objective of this study, and the data acquisition exercise held at the EPRI NDE Center, were focused on evaluating the capabilities of advanced, low-frequency phased-array ultrasonic testing (PA-UT) examination techniques for detection and characterization of implanted circumferential flaws and machined reflectors in a thick-section CASS dissimilar metal weld component. This work was limited to PA-UT assessments using 500 kHz and 800 kHz probes on circumferential flaws only, and evaluated detection and characterization of these flaws and machined reflectors from the CASS safe-end side only. All data were obtained using spatially encoded, manual scanning techniques. The effects of such factors as line-scan versus raster-scan examination approaches were evaluated, and PA-UT detection and characterization performance as a function of inspection frequency/wavelength, were also assessed. A comparative assessment of the data is provided, using length-sizing root-mean-square-error and position/localization results (flaw start/stop information) as the key criteria for flaw characterization performance. In addition, flaw signal-to-noise ratio was identified as the key criterion for detection performance.

  15. The effect of welding fixtures on welding distortions

    OpenAIRE

    2007-01-01

    Purpose: of this paper is to examine the effect of welding fixture used to prevent the distortions duringcooling process utilizing a robot controlled gas metal arc welding method on cooling rate and distortions ofwelded structures.Design/methodology/approach: Using a specially designed welding fixture for a welded steel structure, sixdifferent types of AISI 1020 steel specimens are tested in three different welding speeds and two differentcooling conditions either at fixture or without using ...

  16. Manganese Content Control in Weld Metal During MAG Welding

    Science.gov (United States)

    Chinakhov, D. A.; Chinakhova, E. D.; Sapozhkov, A. S.

    2016-08-01

    The influence of the welding current and method of gas shielding in MAG welding on the content of manganese is considered in the paper. Results of study of the welded specimens of steels 45 when applying welding wire of different formulas and different types of gas shielding (traditional shielding and double-jet shielding) are given. It is found that in MAG welding the value of the welding current and the speed of the gas flow from the welding nozzle have a considerable impact on the chemical composition of the weld metal. The consumable electrode welding under double-jet gas shielding provides the directed gas-dynamics in the welding area and enables controlling the electrode metal transfer and the chemical composition of a weld.

  17. Influence of the Initial Fiber Orientation on the Weld Strength in Welding of Glass Fiber Reinforced Thermoplastics

    Directory of Open Access Journals (Sweden)

    Isabel Fiebig

    2016-01-01

    Full Text Available The welding factors are significantly lower in welding of fiber reinforced thermoplastics than in welding of unreinforced thermoplastics due to the fiber orientation in the weld. This paper presents results from investigations on the influence of the initial fiber orientation on the weld strength in hot plate and vibration welding for glass fiber reinforced polypropylene and polyamide 6. Injection molded specimens are compared to specimens with main initial fiber orientation being longitudinal and transverse to the joining direction. The results of CT analysis of the fiber orientation in the weld show the opportunity to achieve a higher weld strength by using specimens with fibers being initially oriented longitudinally to the joining direction. The influence of the initial fiber orientation in the parts to be welded on the weld strength in hot plate welding is more distinct than in vibration welding.

  18. Studies of welded joints

    Directory of Open Access Journals (Sweden)

    J. M. Krupa

    2010-07-01

    Full Text Available Studies of a welded joint were described. The joint was made as a result of the reconstruction of a truss and one of the possible means to make a repair. The studies were of a simulation character and were targeted at the detection of welding defects and imperfections thatshould be eliminated in a real structure. A model was designed and on this model the tests and examinations were carried out. The modelwas made under the same conditions as the conditions adopted for repair. It corresponded to the real object in shape and dimensions, and in the proposed technique of welding and welding parameters. The model was composed of five plates joined together with twelve beads.The destructive and non-destructive tests were carried out; the whole structure and the respective welds were also examined visually. Thedefects and imperfections in welds were detected by surface methods of inspection, penetration tests and magnetic particle flaw detection.The model of the welded joint was prepared by destructive methods, a technique that would never be permitted in the case of a realstructure. For the investigations it was necessary to cut out the specimens from the welded joint in direction transverse to the weld run. The specimens were subjected to metallographic examinations and hardness measurements. Additionally, the joint cross-section was examined by destructive testing methods to enable precise determination of the internal defects and imperfections. The surface methods were applied again, this time to determine the severity of welding defects. The analysis has proved that, fabricated under proper conditions and with parameters of the welding process duly observed, the welded joint has good properties and repairs of this type are possible in practice.

  19. Fatigue Performance and Fatigue Life Prediction of Aluminum Resistance Spot Welded Tensile Shear Specimen%铝合金点焊拉剪接头疲劳性能及寿命分析

    Institute of Scientific and Technical Information of China (English)

    石燕栋; 郭海丁

    2014-01-01

    Fatigue performance of spot welds of aluminum alloy AA5754 was investigated experi-mentally herein .Fatigue failure mode of spot welded tensile shear specimen was discussed and fatigue crack growth path was also explored .Theoretical crack growth angle was determined for tensile shear specimen ,which was under mix mode I/II loading ,and results were verified by measured angles of failed specimens .Local stress intensity factor at nugget circumference was derived ,modified by actual fatigue crack length in sheet thickness and treated as a fatigue parameter K(i) in fatigue data correla-tion .The proposed fatigue delete parameter is proven efficient in correlating fatigue data and can be used for fatigue life prediction of aluminum resistance spot welds .%研究了铝合金A A 5754点焊拉剪接头的疲劳性能,获得了不同厚度试件的载荷寿命曲线。研究了铝合金焊点的疲劳失效模式,讨论了焊点疲劳裂纹的扩展形式,并测量了裂纹扩展路径与点焊熔核界面之间的角度。分析了点焊拉剪试件在同时承受I型和II型载荷时,疲劳裂纹的扩展方向,并与测量值进行了比较。利用疲劳破坏后沿铝板厚度方向的实际裂纹长度修正了裂纹尖端的局部应力强度因子,提出了评价焊点寿命的疲劳参量 K (i),并对试验数据进行了分析比较。结果证明 K (i)可以有效关联试件尺寸效应和焊点疲劳寿命,能够用于预测焊点疲劳寿命。

  20. Fundamental Laser Welding Process Investigations

    DEFF Research Database (Denmark)

    Bagger, Claus; Olsen, Flemming Ove

    1998-01-01

    In a number of systematic laboratory investigations the fundamental behavior of the laser welding process was analyzed by the use of normal video (30 Hz), high speed video (100 and 400 Hz) and photo diodes. Sensors were positioned to monitor the welding process from both the top side and the rear...... side of the specimen.Special attention has been given to the dynamic nature of the laser welding process, especially during unstable welding conditions. In one series of experiments, the stability of the process has been varied by changing the gap distance in lap welding. In another series...

  1. Effect of weld schedule variation on the weldability and durability of AHSS spot weld joints

    Science.gov (United States)

    Weishaupt, Eric Raymond

    Tensile strength testing and high cycle fatigue testing of advanced high strength steel spot welded shear lap joints were performed for the various weld conditions. The materials used in this study were DP 980, DP 780 and TRIP 780. The microstructure and microhardness of the shear lap joints were examined in an effort to identify the effect of microstructural changes on the strength and fatigue durability of the spot weld specimens. The occurrence of interfacial failure was recorded for the differing weld processes. Several weld schedules were examined and used to produce shear lap spot weld joints, specifically varying the squeeze force and the average current. The weld force used to produce a spot weld does not have a significant effect on the fracture mode of the specimen given the average current is constant. The average current used to produce a spot weld has a significant effect on the fracture mode of the spot weld for several squeeze forces. Interfacial failure of spot welded TRIP 780 can be mitigated using a certain range of currents when welding. This appears to come as a tradeoff for sacrificing the strength of the joint. Higher values of weld strength were obtainable; however, welds that failed with higher strengths also experienced interfacial failure. A fracture mechanics approach to estimating the high cycle fatigue life of the shear lap specimen is also proposed and represents a conservative estimate of the shear lap specimen durability.

  2. FLUXES FOR MECHANIZED ELECTRIC WELDING,

    Science.gov (United States)

    WELDING FLUXES, WELDING ), (* WELDING , WELDING FLUXES), ARC WELDING , WELDS, STABILITY, POROSITY, WELDING RODS, STEEL, CERAMIC MATERIALS, FLUXES(FUSION), TITANIUM ALLOYS, ALUMINUM ALLOYS, COPPER ALLOYS, ELECTRODEPOSITION

  3. Effect of weld reinforcement on axial plastic buckling of welded steel cylindrical shells

    Institute of Scientific and Technical Information of China (English)

    Chu-lin YU; Zhi-ping CHEN; Ji WANG; Shun-juan YAN; Li-cai YANG

    2012-01-01

    The effect of weld reinforcement on axial plastic buckling of welded steel cylindrical shells is investigated through experimental and numerical buckling analysis using six welded steel cylindrical shell specimens.The relationship between the amplitude of weld reinforcement and the axial plastic buckling critical load is explored.The effect of the material yield strength and the number of circumferential welds on the axial plastic buckling is studied.Results show that circumferential weld reinforcement represents a severe imperfect form of axially compressed welded steel cylindrical shells and the axial plastic buckling critical load decreases with the increment of the mean amplitude of circumferential weld reinforcement.The material yield strength and the number of circumferential welds are found to have no significant effect on buckling waveforms; however,the axial plastic buckling critical load can be decreased to some extent with the increase of the number of circumferential welds.

  4. TIG-dressing of High Strength Butt Welded Connection. Part 2: Physical Testing and Modelling

    NARCIS (Netherlands)

    Van Es, S.H.J.; Kolstein, M.H.; Pijpers, R.J.M.; Bijlaard, F.S.K.

    2014-01-01

    Weld improvement techniques are aimed at reducing the notch effects of welds and generally focus on two aspects: a change of geometry of the weld toe and a change of the weld residual stresses. In this paper, fatigue tests are discussed, performed on butt welded specimens in steel grades ranging

  5. TIG-dressing of high strength butt welded connection - Part 2: physical testing and modelling

    NARCIS (Netherlands)

    Es, S.H.J. van; Kolstein, M.H.; Pijpers, R.J.M.; Bijlaard, F.S.K.

    2013-01-01

    Weld improvement techniques are aimed at reducing the notch effects of welds and generally focus on two aspects: a change of geometry of the weld toe and a change of the weld residual stresses. In this paper, fatigue tests are discussed, performed on butt welded specimens in steel grades ranging

  6. TIG-dressing of high strength butt welded connection - Part 2: physical testing and modelling

    NARCIS (Netherlands)

    Es, S.H.J. van; Kolstein, M.H.; Pijpers, R.J.M.; Bijlaard, F.S.K.

    2013-01-01

    Weld improvement techniques are aimed at reducing the notch effects of welds and generally focus on two aspects: a change of geometry of the weld toe and a change of the weld residual stresses. In this paper, fatigue tests are discussed, performed on butt welded specimens in steel grades ranging fro

  7. TIG-dressing of High Strength Butt Welded Connection. Part 2: Physical Testing and Modelling

    NARCIS (Netherlands)

    Van Es, S.H.J.; Kolstein, M.H.; Pijpers, R.J.M.; Bijlaard, F.S.K.

    2014-01-01

    Weld improvement techniques are aimed at reducing the notch effects of welds and generally focus on two aspects: a change of geometry of the weld toe and a change of the weld residual stresses. In this paper, fatigue tests are discussed, performed on butt welded specimens in steel grades ranging fro

  8. Fusion Welding Research.

    Science.gov (United States)

    1983-04-30

    of deep surface depresion due to vortex formation is being studied through a mathematical model. I Welding direction (a)e S (b) Figure 27: Schematic...each weldment. Specimens were cleaned in acetone and alcohol to remove grease and * dirt. They were finally cleaned ultrasonically in a detergent

  9. Welding Curriculum.

    Science.gov (United States)

    Alaska State Dept. of Education, Juneau. Div. of Adult and Vocational Education.

    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.…

  10. Laser Welding Test Results with Gas Atmospheres in Welding Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Chang-Young; Hong, Jin-Tae; Ahn, Sung-Ho; Heo, Sung-Ho; Jang, Seo-Yun; Yang, Tae-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The weld beads of specimens welded under identical conditions in the helium and argon gas were cleaner, more regular, and steadier than those in a vacuum. The penetration depth of the FZ in the vacuum was much deeper than those in the helium and argon gas. To measure the irradiation properties of nuclear fuel in a test reactor, a nuclear fuel test rod instrumented with various sensors must be fabricated with assembly processes. A laser welding system to assemble the nuclear fuel test rod was designed and fabricated to develop various welding technologies of the fuel test rods to joint between a cladding tube and end-caps. It is an air-cooling optical fiber type and its emission modes are a continuous (CW) mode of which the laser generates continuous emission, and pulse (QCW) mode in which the laser internally generates sequences of pulses. We considered the system welding a sample in a chamber that can weld a specimen in a vacuum and inert gas atmosphere, and the chamber was installed on the working plate of the laser welding system. In the chamber, the laser welding process should be conducted to have no defects on the sealing area between a cladding tube and an end-cap.

  11. Influence of weld structure on cross-weld creep behavior in P23 steel

    Energy Technology Data Exchange (ETDEWEB)

    Allen, D.J.; Degnan, C.C. [E.ON Engineering (United Kingdom); Brett, S.J. [RWE npower (United Kingdom); Buchanan, L.W. [Doosan Babcock (United Kingdom)

    2010-07-01

    A thick section pipe weld in low alloy steel P23 has been characterised by cross-weld creep rupture testing at a range of stresses, together with all-weld-metal and parent material testing, under the auspices of the UK High Temperature Power Plant Forum. The results generally show that the weld metal can be weak when tested in the transverse (cross-weld) orientation, and can fail with limited overall ductility by cracking in the zone of refined weld metal beneath the fusion boundary of the superposed weld bead. However, one specimen showed a much superior performance, which could be understood in terms of its locally more creep resistant weld macrostructure. The implications for P23 performance and weld manufacture are discussed. (orig.)

  12. Advanced Welding Concepts

    Science.gov (United States)

    Ding, Robert J.

    2010-01-01

    Four advanced welding techniques and their use in NASA are briefly reviewed in this poster presentation. The welding techniques reviewed are: Solid State Welding, Friction Stir Welding (FSW), Thermal Stir Welding (TSW) and Ultrasonic Stir Welding.

  13. Micro-mechanical properties of 2219 welded joints with twin wire welding

    Institute of Scientific and Technical Information of China (English)

    Xu Wenli; Li Qingfen; Meng Qingguo; Fang Hongyuan; Gao Na

    2006-01-01

    Nanoindentation method was adopted to investigate the distribution regularities of micro-mechanical properties of 2219 twin wire welded joints, thus providing the necessary theoretical basis and guidance for joint strengthening and improvement of welding procedure.Experimental results show that in weld zone, micro-mechanical properties are seriously uneven.Both hardness and elastic modulus distribute as uneven sandwich layers, while micro-mechanical properties in bond area are much more uniform than weld zone;In heat-affected zone of 2219 twin wire welded joint, distribution regularity of hardness is similar to elastic modulus.The average hardness in quenching zone is higher than softening zone, and the average elastic modulus in solid solution zone is slightly higher than softening zone.As far as the whole welded joint is concerned,metal in weld possesses the lowest hardness.For welded specimens without reinforcement, fracture position is the weld when tensioning.While for welded specimens with reinforcement, bond area is the poorest position with joint strength coefficient of 61%.So, it is necessary to strengthen the poor positions-weld and bond area of 2219 twin wire welded joint in order to solve joint weakening of welding this kind of alloy.

  14. Mechanical properties and microstructure of F-82H welded joints using CO{sub 2} laser beam

    Energy Technology Data Exchange (ETDEWEB)

    Yamanouchi, N.; Shiba, K.

    1996-10-01

    The laser welding of F-82H was successfully conducted. The heat affected zone of the welding, was about 21 mm width. It was quite adequate to make small specimens, such as SS-3 type sheet tensile specimen.

  15. The effect of post-welding conditions in friction stir welds: From weld simulation to Ductile Failure

    DEFF Research Database (Denmark)

    Hattel, Jesper Henri; Nielsen, Kim Lau; Tutum, Cem Celal

    2012-01-01

    The post-welding stress state, strain history and material conditions of friction stir welded joints are often strongly idealized when used in subsequent modeling analyses, typically by neglecting one or more of the features above. But, it is obvious that the conditions after welding do influence...... software ANSYS, a thermo-mechanical model is employed to predict the thermally induced stresses and strains during welding, while an in-house finite element code is used to study the plastic flow localization and failure in a subsequent structural analysis. The coupling between the two models is made...... to plastic flow localization was observed, with a substantial influence on the specimen elongation at the onset of localization and thereby failure. This influence is, however, shown to be strongly affected by the applied boundary conditions. Specimens cut from the welded plate, transverse to the weld line...

  16. Reconstituted Charpy impact specimens. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Perrin, J.S.; Wullaert, R.A.; McConnell, P.; Server, W.L.; Fromm, E.O.

    1982-12-01

    The arc stud welding process was used to produce new, full size Charpy V-notch impact specimens from halves of Charpy specimens which had been previously tested. The apparatus was developed such that it could be used not only for unirradiated specimens, but also so that it could be adapted for in-cell use to produce new reconstituted specimens of irradiated material. The materials studied are of interest in nuclear applications. They include A533B, A36, A516-80, submerged arc weld metal (A508 base metal), HY80, cast duplex stainless steel, irradiated A533B, and irradiated submerged arc weld metal (A508 base metal). Both unirradiated and irradiated specimens were successfully produced and subsequently impact tested. In general, there was excellent agreement when comparing the original curves to the subsequent curves generated with reconstituted specimens. This program has shown that the arc stud welding process is well suited for producing reconstituted specimens at a reasonable cost using either unirradiated or irradiated material.

  17. Welding Technician

    Science.gov (United States)

    Smith, Ken

    2009-01-01

    About 95% of all manufactured goods in this country are welded or joined in some way. These welded products range in nature from bicycle handlebars and skyscrapers to bridges and race cars. The author discusses what students need to know about careers for welding technicians--wages, responsibilities, skills needed, career advancement…

  18. Welding characteristics of 27, 40 and 67 kHz ultrasonic plastic welding systems using fundamental- and higher-resonance frequencies.

    Science.gov (United States)

    Tsujino, Jiromaru; Hongoh, Misugi; Yoshikuni, Masafumi; Hashii, Hidekazu; Ueoka, Tetsugi

    2004-04-01

    The welding characteristics of 27, 40 and 67 kHz ultrasonic plastic welding systems that are driven at only the fundamental-resonance frequency vibration were compared, and also those of the welding systems that were driven at the fundamental and several higher resonance frequencies simultaneously were studied. At high frequency, welding characteristics can be improved due to the larger vibration loss of plastic materials. For welding of rather thin or small specimens, as the fundamental frequency of these welding systems is higher and the numbers of driven higher frequencies are driven simultaneously, larger welded area and weld strength were obtained.

  19. The impact of welding wire on the mechanical properties of welded joints

    Directory of Open Access Journals (Sweden)

    Magdalena Mazur

    2014-06-01

    Full Text Available This paper presents results of the mechanical properties of Hardox 450 steel welded joints. These welded joints were made in accordance with welding procedure specifications (WPS, which was prepared and  applied in the Wielton company. Fillers were provided by welding wires with two different diameters. The welding wire was G4Sil with diameter of 1.0 mm and 1.2 mm. The aim of this study was to examine whether the thickness of the welding wire has a direct effect on the properties of welded joints. Test specimens were made in similar parameters of the welding process. Then they were subjected to macroscopic research, tensile strength, impact strength and hardness

  20. Design of Friction Stir Spot Welding Tools by Using a Novel Thermal-Mechanical Approach

    Directory of Open Access Journals (Sweden)

    Zheng-Ming Su

    2016-08-01

    Full Text Available A simple thermal-mechanical model for friction stir spot welding (FSSW was developed to obtain similar weld performance for different weld tools. Use of the thermal-mechanical model and a combined approach enabled the design of weld tools for various sizes but similar qualities. Three weld tools for weld radii of 4, 5, and 6 mm were made to join 6061-T6 aluminum sheets. Performance evaluations of the three weld tools compared fracture behavior, microstructure, micro-hardness distribution, and welding temperature of welds in lap-shear specimens. For welds made by the three weld tools under identical processing conditions, failure loads were approximately proportional to tool size. Failure modes, microstructures, and micro-hardness distributions were similar. Welding temperatures correlated with frictional heat generation rate densities. Because the three weld tools sufficiently met all design objectives, the proposed approach is considered a simple and feasible guideline for preliminary tool design.

  1. Virtual Specimens

    Science.gov (United States)

    de Paor, D. G.

    2009-12-01

    Virtual Field Trips have been around almost as long as the Worldwide Web itself yet virtual explorers do not generally return to their desktops with folders full of virtual hand specimens. Collection of real specimens on fields trips for later analysis in the lab (or at least in the pub) has been an important part of classical field geoscience education and research for generations but concern for the landscape and for preservation of key outcrops from wanton destruction has lead to many restrictions. One of the author’s favorite outcrops was recently vandalized presumably by a geologist who felt the need to bash some of the world’s most spectacular buckle folds with a rock sledge. It is not surprising, therefore, that geologists sometimes leave fragile localities out of field trip itineraries. Once analyzed, most specimens repose in drawers or bins, never to be seen again. Some end up in teaching collections but recent pedagogical research shows that undergraduate students have difficulty relating specimens both to their collection location and ultimate provenance in the lithosphere. Virtual specimens can be created using 3D modeling software and imported into virtual globes such as Google Earth (GE) where, they may be linked to virtual field trip stops or restored to their source localities on the paleo-globe. Sensitive localities may be protected by placemark approximation. The GE application program interface (API) has a distinct advantage over the stand-alone GE application when it comes to viewing and manipulating virtual specimens. When instances of the virtual globe are embedded in web pages using the GE plug-in, Collada models of specimens can be manipulated with javascript controls residing in the enclosing HTML, permitting specimens to be magnified, rotated in 3D, and sliced. Associated analytical data may be linked into javascript and localities for comparison at various points on the globe referenced by ‘fetching’ KML. Virtual specimens open up

  2. Resistance welding

    DEFF Research Database (Denmark)

    Bay, Niels; Zhang, Wenqi; Rasmussen, Mogens H.

    2003-01-01

    Resistance welding comprises not only the well known spot welding process but also more complex projection welding operations, where excessive plastic deformation of the weld point may occur. This enables the production of complex geometries and material combinations, which are often not possible...... to weld by traditional spot welding operations. Such joining processes are, however, not simple to develop due to the large number of parameters involved. Development has traditionally been carried out by large experimental investigations, but the development of a numerical programme system has changed...... this enabling prediction of the welding performance in details. The paper describes the programme in short and gives examples on industrial applications. Finally investigations of causes for failure in a complex industrial joint of two dissimilar metals are carried out combining numerical modelling...

  3. Resistance welding

    DEFF Research Database (Denmark)

    Bay, Niels; Zhang, Wenqi; Rasmussen, Mogens H.

    2003-01-01

    this enabling prediction of the welding performance in details. The paper describes the programme in short and gives examples on industrial applications. Finally investigations of causes for failure in a complex industrial joint of two dissimilar metals are carried out combining numerical modelling......Resistance welding comprises not only the well known spot welding process but also more complex projection welding operations, where excessive plastic deformation of the weld point may occur. This enables the production of complex geometries and material combinations, which are often not possible...... to weld by traditional spot welding operations. Such joining processes are, however, not simple to develop due to the large number of parameters involved. Development has traditionally been carried out by large experimental investigations, but the development of a numerical programme system has changed...

  4. Soldadura (Welding). Spanish Translations for Welding.

    Science.gov (United States)

    Hohhertz, Durwin

    Thirty transparency masters with Spanish subtitles for key words are provided for a welding/general mechanical repair course. The transparency masters are on such topics as oxyacetylene welding; oxyacetylene welding equipment; welding safety; different types of welds; braze welding; cutting torches; cutting with a torch; protective equipment; arc…

  5. Assisting Gas Optimization in CO2 Laser Welding

    DEFF Research Database (Denmark)

    Gong, Hui; Olsen, Flemming Ove

    1996-01-01

    High quality laser welding is achieved under the condition of optimizing all process parameters. Assisting gas plays an important role for sound welds. In the conventional welding process assisting gas is used as a shielding gas to prevent that the weld seam oxidates. In the laser welding process...... assisting gas is also needed to control the laser induced plasma.Assisting gas is one of the most important parameters in the laser welding process. It is responsible for obtaining a quality weld which is characterized by deep penetration, no interior imperfections, i.e. porosity, no crack, homogeneous seam...... are applied with three different flow rates for each of the gases. A number of systematic laboratory experiments is carried out by employing various experimental designs, 33 and 32 Factorial Design. In the experiments a CO2 laser is used to weld thin sheets of mild steel. The welding specimens are evaluated...

  6. New development in welding thin-shell aluminum alloy structures with high strength

    Institute of Scientific and Technical Information of China (English)

    徐文立; 范成磊; 方洪渊; 田锡唐

    2004-01-01

    From the viewpoint of welding mechanics, two new welding methods-welding with trailing peening and welding with trailing impactive rolling were introduced. For aluminum alloy thin-shell structures with high strength, welding will lead to hot cracking, poor joint and distortion. In order to solve them, trailing impactive device was used behind welding torch to impact the different positions of welded joints, thus realizing the welding with free-hot cracking, low distortion and joint strengthening. By use of impactive rolling wheels instead of peening heads, the outlook of welded specimen can be improved and stress concentration at weld toes can be reduced. Equipment of this technology is simple and portable. It can used to weld sheets, longitudinal and ring-like beams of tube-like structures, as well as the thin-shell structures with closed welds such as flanges and hatches. So the technology has the wide application foreground in the fields of aviation and aerospace.

  7. WELDING TORCH

    Science.gov (United States)

    Correy, T.B.

    1961-10-01

    A welding torch into which water and inert gas are piped separately for cooling and for providing a suitable gaseous atmosphere is described. A welding electrode is clamped in the torch by a removable collet sleeve and a removable collet head. Replacement of the sleeve and head with larger or smaller sleeve and head permits a larger or smaller welding electrode to be substituted on the torch. (AEC)

  8. Study on fatigue experiment for transverse butt welds under 2G and 3G weld positions

    Directory of Open Access Journals (Sweden)

    Kang Sung-Wook

    2015-09-01

    Full Text Available Although the transverse butt weld method with ceramic backing strip has been widely used in various industrial fields for its fabricational convenience, it is rarely used in offshore industries since the fatigue strength of the weld joint has not been proved sufficiently. This study conducted fatigue tests for series of butt weld specimens with horizontal (2G and vertical (3G welding positions in order to verify the fatigue strength compared to S-N curve by DNV (Det Norske Veritas, IIW (International Institute of Welding and Eurocode 3. The difference of the 2G specimens and the 3G specimens are investigated in terms of angular distortion and the effect on the fatigue strength are analyzed.

  9. Models for selecting GMA Welding Parameters for Improving Mechanical Properties of Weld Joints

    Science.gov (United States)

    Srinivasa Rao, P.; Ramachandran, Pragash; Jebaraj, S.

    2016-02-01

    During the process of Gas Metal Arc (GMAW) welding, the weld joints mechanical properties are influenced by the welding parameters such as welding current and arc voltage. These parameters directly will influence the quality of the weld in terms of mechanical properties. Even small variation in any of the cited parameters may have an important effect on depth of penetration and on joint strength. In this study, S45C Constructional Steel is taken as the base metal to be tested using the parameters wire feed rate, voltage and type of shielding gas. Physical properties considered in the present study are tensile strength and hardness. The testing of weld specimen is carried out as per ASTM Standards. Mathematical models to predict the tensile strength and depth of penetration of weld joint have been developed by regression analysis using the experimental results.

  10. The fatigue life of a cobalt-chromium alloy after laser welding.

    Science.gov (United States)

    Al-Bayaa, Nabil Jalal Ahmad; Clark, Robert K F; Juszczyk, Andrzej S; Radford, David R

    2011-03-01

    The aim of this study was to investigate the fatigue life of laser welded joints in a commercially available cast cobalt-chromium alloy. Twenty rod shaped specimens (40 mm x 1.5 mm) were cast and sand blasted. Ten specimens were used as controls and the remaining ten were sectioned and repaired using a pulsed Nd: YAG laser welder. All specimens were subjected to fatigue testing (30N - 2Hz) in a controlled environment. A statistically significant difference in median fatigue life was found between as-cast and laser welded specimens (p welded specimens despite 70% penetration of the weld.

  11. Improved design bases of welded joints in seawater

    DEFF Research Database (Denmark)

    Ólafsson, Ólafur Magnús

    The presented work aims to investigate and establish a precise, thorough and detailed database from series of experimental testing of submerged arc welded, SAW, specimens of various thicknesses typically applied in offshore structures and foundations. Additionally, the testing was performed in two...... welded joints were thereafter compared directly to the traditional SAW specimens in order to investigate the two different welding techniques. The laser hybrid welding technique offers great potential in lowering the cost of energy associated with offshore structures....... therefore received much attention from universities, research institutions along with industry as it is of significant practical importance for all fatigue loaded structures, such as e.g. marine structures. As-welded SAW specimens of three different thicknesses, manufactured by Lindoe Welding Technology A...

  12. TIG-dressing of High Strength Butt Welded Connection. Part 2: Physical Testing and Modelling

    OpenAIRE

    Van Es, S.H.J.; Kolstein, M.H.; Pijpers, R.J.M.; Bijlaard, F.S.K.

    2014-01-01

    Weld improvement techniques are aimed at reducing the notch effects of welds and generally focus on two aspects: a change of geometry of the weld toe and a change of the weld residual stresses. In this paper, fatigue tests are discussed, performed on butt welded specimens in steel grades ranging from S460 to S1100 in the TIG-dressed condition. The test results are compared with modelled fatigue strength according to the notch stress theory and similar specimens in the as-welded condition. The...

  13. Joining characteristics of titanium-based orthodontic wires connected by laser and electrical welding methods.

    Science.gov (United States)

    Matsunaga, Junko; Watanabe, Ikuya; Nakao, Noriko; Watanabe, Etsuko; Elshahawy, Waleed; Yoshida, Noriaki

    2015-01-01

    This study investigated the possibility of electrical and laser welding to connect titanium-based alloy (beta-titanium and nickel-titanium) wires and stainless-steel or cobalt-chromium alloy wires for fabrication of combination arch-wires. Four kinds of straight orthodontic rectangular wires (0.017 × 0.025 inch) were used: stainless-steel (S-S), cobalt-chromium (Co-Cr), beta-titanium alloy (β-Ti), and nickel-titanium (Ni-Ti). Homogeneous and heterogeneous end-to-end joints (15 mm long each) were made by electrical welding and laser welding. Non-welded wires (30 mm long) were also used as a control. Maximum loads at fracture (N) and elongation (%) were measured by conducting tensile test. The data (n = 10) were statistically analyzed using analysis of variance/Tukey test (P welding and those of the S-S/S-S and Co-Cr/Co-Cr specimens welded by laser. On the other hand, the laser-welded Ni-Ti/Ni-Ti and β-Ti/β-Ti specimens exhibited higher values of the ML and EL compared to those of the corresponding specimens welded by electrical method. In the heterogeneously welded combinations, the electrically welded Ni-Ti/S-S, β-Ti/S-S and β-Ti/Co-Cr specimens showed significantly (P welded by laser. Electrical welding exhibited the higher values of maximum load at fracture and elongation for heterogeneously welded combinations than laser-welding.

  14. Mechanical Properties of Welded Deformed Reinforcing Steel Bars

    Directory of Open Access Journals (Sweden)

    Ghafur H. Ahmed

    2015-05-01

    Full Text Available Reinforcement strength, ductility and bendability properties are important components in design of reinforced concrete members, as the strength of any member comes mainly from reinforcement. Strain compatibility and plastic behaviors are mainly depending on reinforcement ductility. In construction practice, often welding of the bars is required. Welding of reinforcement is an instant solution in many cases, whereas welding is not a routine connection process. Welding will cause deficiencies in reinforcement bars, metallurgical changes and re-crystallization of microstructure of particles. Weld metal toughness is extremely sensitive to the welding heat input that decreases both of its strength and ductility. For determining the effects of welding in reinforcement properties, 48 specimens were tested with 5 different bar diameters, divided into six groups. Investigated parameters were: properties of un-welded bars; strength, ductility and density of weld metal; strength and ductility reduction due to heat input for bundled bars and transverse bars; welding effect on bars’ bending properties; behavior of different joint types; properties of three weld groove shapes also the locations and types of failures sections. Results show that, strength and elongation of the welded bars decreased by (10-40% and (30-60% respectively. Cold bending of welded bars and groove welds shall be prevented.

  15. Weld Bead Size, Microstructure and Corrosion Behavior of Zirconium Alloys Joints Welded by Pulsed Laser Spot Welding

    Science.gov (United States)

    Cai, Chuang; Li, Liqun; Tao, Wang; Peng, Genchen; Wang, Xian

    2016-09-01

    Pulsed laser spot welding of intersection points of zirconium alloys straps was performed. Weld bead size, microstructure and the corrosion behavior of weld bead were investigated. With the increasing laser peak power or number of shots, the weld width of the beads increased, the protrusion decreased and the dimple increased with further increase in heat input. The fusion zone consisted of a mixture of αZr and residual βZr phases. After annealing treatment, βNb and Zr(Fe, Nb)2 second phase particles were precipitated inter- and intragranular of αZr grains adequately. The oxide thickness of annealed weld bead was about 3.90 μm, decreased by about 18.1% relative to the 4.76 μm of as-welded specimen corroded at 400 °C and 10.3 MPa for 20 days. The corrosion resistance of annealed specimen was better than that of as-welded specimen, since the second phase particles exerted better corrosion resistance, and the content of Nb in βZr and the fraction of βZr decreased after the annealing treatment.

  16. Development of simplified finite element models for welded joints

    Energy Technology Data Exchange (ETDEWEB)

    Song, Seong Il; Ahn, Sung Wook; Kim, Young Geul; Kim, Hyun Gyu [Dept. of Mechanical and Automotive Engineering, Seoul National University of Science and Technology, Seoul (Korea, Republic of)

    2015-11-15

    In this paper, we develop simplified finite element (FE) models for butt-, lap- and T-welded joints by performing numerical and experimental experiments. Three-point bending tests of butt- and lap-welded specimens are performed to obtain the stiffness of the specimens and the strains at points near the welding beads. Similarly the stiffness and strains of T-welded specimen are measured by applying a point load at the end of the specimen. To develop simplified FE models, we consider the shape parameters of width, thickness and the angle of weld elements in the numerical simulations. The shape parameters of the simplified FE models are determined by building linear regression models for the experimental data sets.

  17. Development of Simplified Finite Element Models for Welded Joints

    Energy Technology Data Exchange (ETDEWEB)

    Song, Seong Il; Ahn, Sung Wook; Kim, Young Geul; Kim, Hyun Gyu [Seoul National Univ. of Sci. and Tech., Seoul (Korea, Republic of)

    2015-11-15

    In this paper, we develop simplified finite element (FE) models for butt-, lap- and T-welded joints by performing numerical and experimental experiments. Three-point bending tests of butt- and lap-welded specimens are performed to obtain the stiffness of the specimens and the strains at points near the welding beads. Similarly the stiffness and strains of T-welded specimen are measured by applying a point load at the end of the specimen. To develop simplified FE models, we consider the shape parameters of width, thickness and the angle of weld elements in the numerical simulations. The shape parameters of the simplified FE models are determined by building linear regression models for the experimental data sets.

  18. Laser Welding of Large Scale Stainless Steel Aircraft Structures

    Science.gov (United States)

    Reitemeyer, D.; Schultz, V.; Syassen, F.; Seefeld, T.; Vollertsen, F.

    In this paper a welding process for large scale stainless steel structures is presented. The process was developed according to the requirements of an aircraft application. Therefore, stringers are welded on a skin sheet in a t-joint configuration. The 0.6 mm thickness parts are welded with a thin disc laser, seam length up to 1920 mm are demonstrated. The welding process causes angular distortions of the skin sheet which are compensated by a subsequent laser straightening process. Based on a model straightening process parameters matching the induced welding distortion are predicted. The process combination is successfully applied to stringer stiffened specimens.

  19. Galvanic Corrosion Behavior of Microwave Welded and Post-weld Heat-Treated Inconel-718 Joints

    Science.gov (United States)

    Bansal, Amit; Sharma, Apurbba Kumar; Kumar, Pradeep

    2017-05-01

    In the present study, corrosion behavior of microwave welded Inconel-718 at various conditions was investigated. Welding of Inconel-718 in 980 °C solution-treated condition was performed using microwave hybrid heating technique. The microwave welds were subjected to post-heat treatment for improving its microstructure and mechanical properties by solubilizing the Nb-enriched Laves phase. The microstructural features of the fabricated welds at various conditions were investigated through scanning electron microscopy. The electrochemical testing results revealed that Inconel-718 welds were galvanic corroded when they were anodically polarized in 3.5 wt.% NaCl solution at 28 °C. The difference in the corrosion potentials between the base metal (BM) and fusion zone (FZ) in an Inconel-718 weld was the main factor for galvanic corrosion. The highest corrosion was occurred in the as-welded/aged weldments, followed by 980 °C solution-treated and aged weldments, as-welded specimen, and 1080 °C solution-treated and aged (1080STA) weldments. The least galvanic corrosion was occurred in the 1080STA specimens due to almost uniform microstructure developed in the weldment after the treatment. Thus, it was possible to minimize the galvanic corrosion in the microwave welded Inconel-718 by 1080STA treatment which resulted in reducing the difference in corrosion potentials between the BM and the FZ.

  20. Behavior of a crack within a Dissimilar Metal Weld Part by using an Overlay Weld

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kang Soo; Lee, Ho Jin; Lee, Bong Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-05-15

    In recent years, the dissimilar metal welds, Alloy 82/182 welds, used to connect the stainless steel piping and low alloy steel or carbon steel components in a nuclear reactor piping system have experienced a cracking due to a primary water stress corrosion (PWSCC).It is well known that one reason for the cracking is the residual stress by the weld. But, it is difficult to estimate the weld residual stress exactly due to the many parameters for the welding process. In this paper, a Butt model weld specimen was manufactured and the residual stresses of the weld specimen were measured by the X-Ray method and a Hole Drilling Technique. These results were compared with the results of the Butt FEM Model to confirm the confidence of the FEM input. Also, an analysis of the Crack FEM models made by the ABAQUS Code was performed to estimate the behavior of a crack within a Dissimilar Metal Weld Part (DMWP) when an overlay weld on the DMWP was done.

  1. ELECTRIC WELDING EQUIPMENT AND AUTOMATION OF WELDING IN CONSTRUCTION,

    Science.gov (United States)

    WELDING , *ARC WELDING , AUTOMATION, CONSTRUCTION, INDUSTRIES, POWER EQUIPMENT, GENERATORS, POWER TRANSFORMERS, RESISTANCE WELDING , SPOT WELDING , MACHINES, AUTOMATIC, STRUCTURES, WIRING DIAGRAMS, USSR.

  2. Syllabus in Trade Welding.

    Science.gov (United States)

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    The syllabus outlines material for a course two academic years in length (minimum two and one-half hours daily experience) leading to entry-level occupational ability in several welding trade areas. Fourteen units covering are welding, gas welding, oxyacetylene welding, cutting, nonfusion processes, inert gas shielded-arc welding, welding cast…

  3. The study on the properties of AISI 4140 and AISI 1040 steel rods welded by friction welding

    OpenAIRE

    Thanee Toomprasen; Chawalit Thinvongpituk; Sukangkana Talangkun

    2014-01-01

    This paper is aimed to investigate the properties of joint between AISI 4140 and AISI 1040 welded by friction welding. The specimens were prepared in round shape of 13 mm diameter and 100 mm long. They were welded by friction welding method under the following conditions; friction pressure of 183 MPa, friction time of 12 sec, upset pressure of 428 MPa, upset time of 7 sec. and rotational speed of 1400 rpm. The strength and hardness were tested on the welded area. The result showed finer grain...

  4. A new method for welding aluminum alloy LY12CZ sheet with high strength

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    From the viewpoint of welding mechanics, a new welding technology-trailing peening was applied firstly to weld aluminum alloy LY12CZ sheet with high susceptibility to hot cracking. Trailing peening can exert a transverse extrusion strain on the metal in brittle temperature region (BTR) which can compensate for the tensioning strain during the cooling procedure post welding. So, welding hot cracking of LY12CZ sheet can be controlled effectively on the special jig for hot cracking experiment, and the phenomenon of hot cracking can't be found in specimens with large dimensions finally. At the same time, welding with trailing peening can decrease welding distortion caused by longitudinal and transverse shrinkage of weld obviously. Due to strengthening the poor position-weld toe during the process of welding, the residual stress distribution of welded joint is more reasonable. Contrast with conventional welding, mechanical properties such as tensile strength, prolongation ratio and cold-bending angle of welded joint with trailing peening can be improved obviously, and rupture position of welded joint transits from weld toe at conventional welding to weld metal at trailing peening. So, welding with trailing peening can be regarded as a dynamic welding method with low stress, little distortion and hot cracking-free really. As far as theoretical analysis is concerned, the technology of trailing peening can be used to weld the materials with high susceptibility to hot cracking such as LY12CZ and LD10, and solve the welding distortion of thin plate-shell welded structures which contain closed welds such as flange. In addition, the technology of trailing peening has many advantages: simple device, high efficiency, low cost and flexible application which make the welding method have widely applied foreground in the field of aeronautics and aerospace.

  5. The reliability of untempered end plug welds on HT9-clad IFR fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, D C; Porter, D L

    1987-02-01

    Welding generally leaves residual stresses in transformed weld zones, which can initiate cracks from flaws already present in the weld zones. When HT9 cools from welding temperatures, a martensite phase forms in the weld fusion zone and heat-affected zone. Because this martensite phase is hard and brittle, it is particularly susceptible to cracking aggravated by residual stresses. This causes concern over the use of untempered welds on HT9-clad fuel elements. To determine if residual stresses present in end-plug weld zones would affect fuel pin performance, HT9 capsules with prototypic TIG- and CD-welded end plugs (in the tempered and as-welded conditions) were pressurized to failure at room temperature, 550{sup 0}C, and 600{sup 0}C. None of the capsules failed in a weld zone. To determine the effects of reactor operating temperatures on untempered welds, prototypic TIG welds were tempered at reactor bulk sodium temperature and an expected sodium outlet temperature for various lengths of time. Subsequent tensile and burst tests of these specimens proved that any embrittling effects that may have been induced in these welds were of no consequence. Hardness tests on longitudinal sections of welds indicated the amount of tempering a weld will receive inreactor after relatively short lengths of time. The pressure burst tests proved that untemperted welds on HT9-clad fuel elements are as reliable as tempered welds; any residual stresses in untempered weld zones were of no consequence. The tempering test showed that welds used in the as-welded condition will sufficiently temper in 7 days at 550{sup 0}C, but will not, sufficiently temper in 7 days at bulk sodium temperature. A comparison of the structure of laser welds to those of CD and TIG welds indicated that untempered laser welds will perform and temper in a manner similar to the TIG welds tested in this effort.

  6. Distribution Characteristics of Weld Residual Stress on Butt Welded Dissimilar Metal Plate

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyoung Soo; Park, Chi Yong [KEPCO Research Institute, Daejeon (Korea, Republic of); Kim, Maan Won [Korea Hydro and Nuclear Power Co., Seoul (Korea, Republic of); Park, Jai Hak [Chungbuk National University, Cheongju (Korea, Republic of)

    2010-09-15

    In this study, the weld residual stress distribution at a dissimilar-metal welded plate of low alloy carbon steel and stainless steel, which are widely used in nuclear power plants, was characterized. A plate mock-up with butt welding was fabricated using SA 508 low alloy steel and Type 304 stainless steel plates and the residual stresses were measured by the X-ray diffraction method after electrolytic polishing of the plate specimen. Finite element analysis was carried out in order to simulate the butt welding of dissimilar metal plate, and the calculated weld residual stress distribution was compared with that obtained from the measured data. The characteristics of the three-dimensional residual stress distribution in a butt weld of dissimilar metal plates were investigated by comparing the measured and calculated residual stress data.

  7. Evaluation of anodic behavior of commercially pure titanium in tungsten inert gas and laser welds.

    Science.gov (United States)

    Orsi, Iara Augusta; Raimundo, Larica B; Bezzon, Osvaldo Luiz; Nóbilo, Mauro Antonio de Arruda; Kuri, Sebastião E; Rovere, Carlos Alberto D; Pagnano, Valeria Oliveira

    2011-12-01

    This study evaluated the resistance to corrosion in welds made with Tungsten Inert Gas (TIG) in specimens made of commercially pure titanium (cp Ti) in comparison with laser welds. A total of 15 circular specimens (10-mm diameter, 2-mm thick) were fabricated and divided into two groups: control group-cp Ti specimens (n = 5); experimental group-cp Ti specimens welded with TIG (n = 5) and with laser (n = 5). They were polished mechanically, washed with isopropyl alcohol, and dried with a drier. In the anodic potentiodynamic polarization assay, measurements were taken using a potentiostat/galvanostat in addition to CorrWare software for data acquisition and CorrView for data visualization and treatment. Three curves were made for each working electrode. Corrosion potential values were statistically analyzed by the Student's t-test. Statistical analysis showed that corrosion potentials and passive current densities of specimens welded with TIG are similar to those of the control group, and had lower values than laser welding. TIG welding provided higher resistance to corrosion than laser welding. Control specimens welded with TIG were more resistant to local corrosion initiation and propagation than those with laser welding, indicating a higher rate of formation and growth of passive film thickness on the surfaces of these alloys than on specimens welded with laser, making it more difficult for corrosion to occur. © 2011 by the American College of Prosthodontists.

  8. Welded Kimberlite?

    Science.gov (United States)

    van Straaten, B. I.; Kopylova, M. G.; Russell, J. K.; Scott Smith, B. H.

    2009-05-01

    Welding of pyroclastic deposits generally involves the sintering of hot glassy vesicular particles and requires the presence of a load and/or high temperatures. Welding can occur on various scales as observed in large welded pyroclastic flows, in small-volume agglutinated spatter rims, or as in coalesced clastogenic lava flows. In all these examples welding occurs mainly by reduction or elimination of porosity within the vesicular clasts and/or inter-clast pore space. The end result of welding in pyroclastic deposits is to produce dense, massive, coherent deposits. Here, we present a possible new end-member of the welding process: welding of non- vesicular pyroclasts in intra-crater kimberlite deposits. Kimberlite melt is a low-viscosity liquid carrying abundant crystals. Because of this, kimberlite eruptions generally produce non-vesicular pyroclasts. During welding, these pyroclast cannot deform by volume reduction to form typical fiamme. As a result, welding and compaction in kimberlites proceeds via the reduction of inter-clast pore space alone. The lack of porous pyroclasts limits the maximum amount of volumetric strain within pyroclastic kimberlite deposits to about 30%. This value is substantially lower than the limiting values for welding of more common felsic pyroclastic flows. The lower limit for volumetric strain in welded kimberlite deposits severely restricts the development of a fabric. In addition, pyroclastic kimberlite deposits commonly feature equant-shaped pyroclasts, and equant-shaped crystals. This, in turn, limits the visibility of the results of compaction and pore space reduction, as there are few deformable markers and elongate rigid markers that are able to record the strain during compaction. These features, together with the low viscosity of kimberlite magma and the stratigraphic position of these kimberlite deposits within the upper reaches of the volcanic conduit, call for careful interpretation of coherent-looking rocks in these

  9. CHARACTERISATION OF SPOT WELD GROWTH ON DISSIMILAR JOINTS WITH DIFFERENT THICKNESSES

    Directory of Open Access Journals (Sweden)

    Nachimani Charde

    2012-06-01

    Full Text Available A sound weld from spot welding is what most manufacturers desire and prefer for mechanical assemblies in their systems. The robustness is mainly attributed to the joining mechanism of mechanical parts. This paper focuses on the effect of parametric changes for dissimilar joints using 304 austenitic stainless steel and carbon steel of two different thicknesses. A pneumatic-based spot welder was used to accomplish the entire welding process. The parameters varied during the experiments are the welding current and welding time, while the electrode pressing force and electrode tip size are kept constant. The welding process began from a poor weld and moved on to a better weld by increasing the process parameters. However, this study is limited to the basic parametric variation to find the optimum parametric setup for 1 and 2 mm base metals. The welded specimens are subjected to tensile, hardness and metallurgical tests to characterise the spot weld growth for both thicknesses.

  10. Effects of Post-Weld Heat Treatment on the Mechanical Properties of Similar- and Dissimilar-Alloy Friction Stir Welded Blanks

    Science.gov (United States)

    Zadpoor, Amir Abbas; Sinke, Jos

    2011-01-01

    Friction stir welding is a solid state joining process with relatively low welding temperatures. Nevertheless, the mechanical properties of friction stir welded blanks are degraded after welding. Indeed, both strength and ductility of the welds are decreased after welding. Often, the resulting friction stir welded blanks need to be formed to their final structural shape. Therefore, the formability of friction stir welded blanks is of primary importance in the manufacturing of structural parts. This paper studies how the mechanical properties and particularly formability of friction stir welded blanks can be improved by applying a post weld heat treatment. Two aluminum alloys from 2000 and 7000 series, namely 2024-T3 and 7075-T6, are selected for the study. The sheet thickness of both materials is 2,0 mm. The selected alloys are welded in three configurations: 2024-T3 and 2024-T3, 7075-T6 and 7075-T6, and 2024-T3 and 7075-T6. The resulting welds are naturally aged for a few months. Three sets of standard dog bone shape tensile test specimens are then machined from the welds. The first set of the specimens is tested without any heat treatment. The second set of the specimens is solution heat treated and quenched before testing. The third set of the specimens is solution heat treated, quenched, and naturally aged for a week before testing. The mechanical properties of the three different sets of specimens are compared with each other. It is shown that careful selection of post weld heat-treatment can greatly improve the formability of friction stir welded blanks.

  11. Laser Welding of TC-1 Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    Hanbin DU; Lunji HU; Xiyuan HU; Jianhua LIU

    2003-01-01

    The technology of CO2 laser welding and joint properties of titanium alloy were investigated. The problem of moltenpool protection was resolved by designing a shielding trailer and a special clamp. Joints with silvery appearance wereobtained, which have no pore and crack. In addition, the welding speed could reach 3 m/min for the plate of 1.5 mmthickness being penetrated. The reason of the porosity formation in partial penetration joints is that the keyholescan be easily cut apart in the radial direction, which makes the gas enclosed in the molten pool. The surface oxideof specimens can not affect the porosity formation in welds directly.

  12. FATIGUE WELDING JOINT RESISTANCE OF MINING DUMP TRUCK BEARING CONSTRUCTIONS

    Directory of Open Access Journals (Sweden)

    A. A. Rakitsky

    2010-01-01

    Full Text Available The paper investigates a possibility to apply European norms on designing of welded constructions for frames of heavy-load mining dump trucks. Comparison of results concerning tests of welding joint specimen made of local steel with recommended standards of fatigue curves is executed in the paper. The paper reveals that while forecasting resource of automotive constructions with the accepted practical accuracy it is possible to use generalized fatigue resistance characteristics of standard welding joints. 

  13. Weldability prediction of high strength steel S960QL after weld thermal cycle simulation

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2014-10-01

    Full Text Available This paper presents weld thermal cycle simulation of high strength steel S960QL, and describes influence of cooling time t8/5 on hardness and impact toughness of weld thermal cycle simulated specimens. Furthermore, it presents analysis of characteristic fractions done by electron scanning microscope which can contribute to determination of welding parameters for S960QL steel.

  14. The mechanical measuring method of welding heat source efficiency

    Institute of Scientific and Technical Information of China (English)

    Zhang Jianqiang; Zhang Guodong; He Jie; Wang Chengquan; Chen Bingquan

    2007-01-01

    Based on the principle of residual deformation induced by superposition of the welding residual stress and working stress, the welding heat source efficiency has been determined by measuring displacement changes of specimens under loading and unloading in tensile tests, and combining with calculating welding parameters. Meanwhile, the welding heat source efficiencies obtained are compared with those of the measuring-calculating method. The research results show that the welding heat source efficiencies are almost the same as those obtained by the measuring-calculating method. Therefore, the welding heat source efficiency can be determined accurately by this method, and a new determining method of the heat source efficiency for the welding heat process calculating has been provided.

  15. Welding Curtains

    Science.gov (United States)

    1984-01-01

    Concept of transparent welding curtains made of heavy duty vinyl originated with David F. Wilson, President of Wilson Sales Company. In 1968, Wilson's curtains reduced glare of welding arc and blocked ultraviolet radiation. When later research uncovered blue light hazards, Wilson sought improvement of his products. He contracted Dr. Charles G. Miller and James B. Stephens, both of Jet Propulsion Laboratory (JPL), and they agreed to undertake development of a curtain capable of filtering out harmful irradiance, including ultraviolet and blue light and provide protection over a broad range of welding operation. Working on their own time, the JPL pair spent 3 years developing a patented formula that includes light filtering dyes and small particles of zinc oxide. The result was the Wilson Spectra Curtain.

  16. Microstructure And Weld Cracking In Inconel 718(R)

    Science.gov (United States)

    Thompson, R. G.

    1988-01-01

    Theories on relationship between metallurgy and microfissuring confirmed. Report describes research on effects of microstructure on cracking of heat-affected zones of welds in Inconel 718(R) alloy. In experimental studies, specimens subjected to various combinations of time-varying thermal and mechanical stresses to simulate welding conditions and to identify physical and chemical effects causing microfissuring.

  17. Microstructure And Weld Cracking In Inconel 718(R)

    Science.gov (United States)

    Thompson, R. G.

    1988-01-01

    Theories on relationship between metallurgy and microfissuring confirmed. Report describes research on effects of microstructure on cracking of heat-affected zones of welds in Inconel 718(R) alloy. In experimental studies, specimens subjected to various combinations of time-varying thermal and mechanical stresses to simulate welding conditions and to identify physical and chemical effects causing microfissuring.

  18. Weld repair of helium degraded reactor vessel material

    Energy Technology Data Exchange (ETDEWEB)

    Kanne, W.R. Jr.; Lohmeier, D.A.; Louthan, M.R. Jr.; Rankin, D.T.; Franco-Ferreira, E.A. (Westinghouse Savannah River Co., Aiken, SC (United States)); Bruck, G.J.; Madeyski, A.; Shogan, R.P.; Lessmann, G.G. (Westinghouse Electric Corp., Pittsburgh, PA (United States). Science and Technology Center)

    1990-01-01

    Welding methods for modification or repair of irradiated nuclear reactor vessels are being evaluated at the Savannah River Site. A low-penetration weld overlay technique has been developed to minimize the adverse effects of irradiation induced helium on the weldability of metals and alloys. This technique was successfully applied to Type 304 stainless steel test plates that contained 3 to 220 appm helium from tritium decay. Conventional welding practices caused significant cracking and degradation in the test plates. Optical microscopy of weld surfaces and cross sections showed that large surface toe cracks formed around conventional welds in the test plates but did not form around overlay welds. Scattered incipient underbead cracks (grain boundary separations) were associated with both conventional and overlay test welds. Tensile and bend tests were used to assess the effect of base metal helium content on the mechanical integrity of the low-penetration overlay welds. The axis of tensile specimens was perpendicular to the weld-base metal interface. Tensile specimens were machined after studs were resistance welded to overlay surfaces.

  19. Weld repair of helium degraded reactor vessel material

    Energy Technology Data Exchange (ETDEWEB)

    Kanne, W.R. Jr.; Lohmeier, D.A.; Louthan, M.R. Jr.; Rankin, D.T.; Franco-Ferreira, E.A. [Westinghouse Savannah River Co., Aiken, SC (United States); Bruck, G.J.; Madeyski, A.; Shogan, R.P.; Lessmann, G.G. [Westinghouse Electric Corp., Pittsburgh, PA (United States). Science and Technology Center

    1990-12-31

    Welding methods for modification or repair of irradiated nuclear reactor vessels are being evaluated at the Savannah River Site. A low-penetration weld overlay technique has been developed to minimize the adverse effects of irradiation induced helium on the weldability of metals and alloys. This technique was successfully applied to Type 304 stainless steel test plates that contained 3 to 220 appm helium from tritium decay. Conventional welding practices caused significant cracking and degradation in the test plates. Optical microscopy of weld surfaces and cross sections showed that large surface toe cracks formed around conventional welds in the test plates but did not form around overlay welds. Scattered incipient underbead cracks (grain boundary separations) were associated with both conventional and overlay test welds. Tensile and bend tests were used to assess the effect of base metal helium content on the mechanical integrity of the low-penetration overlay welds. The axis of tensile specimens was perpendicular to the weld-base metal interface. Tensile specimens were machined after studs were resistance welded to overlay surfaces.

  20. Sturdy on Orbital TIG Welding Properties for Nuclear Fuel Test Rod

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Changyoung; Hong, Jintae; Kim, Kahye; Huh, Sungho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    We developed a precision TIG welding system that is able to weld the seam between end-caps and a fuel cladding tube for the nuclear fuel test rod and rig. This system can be mainly classified into an orbital TIG welder (AMI, M-207A) and a pressure chamber. The orbital TIG welder can be independently used, and it consists of a power supply unit, a microprocessor, water cooling unit, a gas supply unit and an orbital weld head. In this welder, the power supply unit mainly supplies GTAW power for a welding specimen and controls an arc starting of high frequency, supping of purge gas, arc rotation through the orbital TIG welding head, and automatic timing functions. In addition, the pressure chamber is used to make the welded surface of the cladding specimen clean with the inert gas filled inside the chamber. To precisely weld the cladding tube, a welding process needs to establish a schedule program for an orbital TIG welding. Therefore, the weld tests were performed on a cladding tube and dummy rods under various conditions. This paper describes not only test results on parameters of the purge gas flow rates and the chamber gas pressures for the orbital TIG welding, but also test results on the program establishment of an orbital TIG welding system to weld the fuel test rods. Various welding tests were performed to develop the orbital TIG welding techniques for the nuclear fuel test rod. The width of HAZ of a cladding specimen welded with the identical power during an orbital TIG welding cycle was continuously increased from a welded start-point to a weld end-point because of heat accumulation. The welding effect of the PGFR and CGP shows a relatively large difference for FSS and LSS. Each hole on the cladding specimens was formed in the 1bar CGP with the 20L/min PGFR but not made in the case of the PGFR of 10L/min in the CGP of 2bar. The optimum schedule program of the orbital TIG welding system to weld the nuclear fuel test rod was established through the program

  1. ARc Welding (Industrial Processing Series).

    Science.gov (United States)

    ARC WELDING , *BIBLIOGRAPHIES), (*ARC WELDS, BIBLIOGRAPHIES), ALUMINUM ALLOYS, TITANIUM ALLOYS, CHROMIUM ALLOYS, METAL PLATES, SPOT WELDING , STEEL...INERT GAS WELDING , MARAGING STEELS, MICROSTRUCTURE, HEAT RESISTANT ALLOYS, HEAT RESISTANT METALS, WELDABILITY, MECHANICAL PROPERTIES, MOLYBDENUM ALLOYS, NICKEL ALLOYS, RESISTANCE WELDING

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

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Changheui [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)], E-mail: chjang@kaist.ac.kr; Lee, Jounghoon [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Sung Kim, Jong; Eun Jin, Tae [Korea Power Engineering Company, 360-9 Mabuk-ri, Guseong-eup, Yongin-si, Gyeonggi-do 449-713 (Korea, Republic of)

    2008-09-15

    In several locations of pressurized water reactors, dissimilar metal welds using Inconel welding wires are used to join the low alloy steel components to stainless-steel pipes. Because of the existence of different materials and chemistry variation within welds, mechanical properties, such as tensile and fracture properties, are expected to show spatial variation. For design and integrity assessment of the dissimilar welds, these variations should be evaluated. In this study, dissimilar metal welds composed of low alloy steel, Inconel 82/182 weld, and stainless steel were prepared by gas tungsten arc welding and shielded metal arc welding techniques. Microstructures were observed using optical and electron microscopes. Typical dendrite structures were observed in Inconel 82/182 welds. Tensile tests using standard and mini-sized specimens and micro-hardness tests were conducted to measure the variation in strength along the thickness of the weld as well as across the weld. In addition, fracture toughness specimens were taken at the bottom, middle, and top of the welds and tested to evaluate the spatial variation along the thickness. It was found that while the strength is about 50-70 MPa greater at the bottom of the weld than at the top of the weld, fracture toughness values at the top of the weld are about 70% greater than those at the bottom of the weld.

  3. Prediction of Welding Deformation and Residual Stresses in Fillet Welds Using Indirect Couple Field FE Method

    Directory of Open Access Journals (Sweden)

    Asifa Khurram

    2013-03-01

    Full Text Available Fillet welds are extensively used in shipbuilding, automobile and other industries. Heat concentrated at a small area during welding induces distortions and residual stresses, affecting the structural strength. In this study, indirect coupled-field method is used to predict welding residual stresses and deformation in a fillet joint due to welding on both sides. 3-D nonlinear thermal finite element analysis is performed in ANSYS software followed by a structural analysis. Symmetrical boundary conditions are applied on half of the model for simplification. Results of FE structure analysis predict residual stresses in the specimen. A comparison of simulation results with experimental values proves the authenticity of the technique. The present study can be extended for complex structures and welding techniques.

  4. Initiation and growth of microcracks in high strength steel butt welds

    Science.gov (United States)

    Olsen, Edward

    1993-05-01

    Early tests such as the explosion bulge test created a preference for overmatched welds (welds which are stronger than the base metal) which eventually became codified for many structural applications. While an overmatched system offers advantages such as the shedding of strain to the base plate, it requires the use of expensive fabrication procedures to avoid cracking. Undermatched welding of some high strength steels may offer reductions in welding costs with little sacrifice in weld performance or low cycle fatigue integrity. An experimental study was carried out to observe microcrack initiation and growth of overmatched and undermatched butt welded high strength steel samples using globally elastic low cycle fatigue testing. First, 1 inch thick HY-80 and HY-100 base plates were multipass, spray gas metal arc welded (GMAW) with overmatching and undermatching filler metal using a semiautomatic welding machine. Second, 1/4 inch thick MIL-A-46100 high hardness armor plates (HHA) were manually, two pass spray GMAW welded with two grades of undermatching consumables. Weld reinforcements were removed from all HY specimens and six HHA specimens. All specimens had a crack initiator slit machined in the test section. The specimens were fatigue tested by transverse tensile loading with a 12 to 13 Hz tension-tension profile. The loading range was from 10% to 85% of the tensile strength of the HY steel base plate and HHA weld metal respectively. Crack initiation and propagation was observed in situ using a confocal scanning laser microscope.

  5. Inspection of thick welded joints using laser-ultrasonic SAFT.

    Science.gov (United States)

    Lévesque, D; Asaumi, Y; Lord, M; Bescond, C; Hatanaka, H; Tagami, M; Monchalin, J-P

    2016-07-01

    The detection of defects in thick butt joints in the early phase of multi-pass arc welding would be very valuable to reduce cost and time in the necessity of reworking. As a non-contact method, the laser-ultrasonic technique (LUT) has the potential for the automated inspection of welds, ultimately online during manufacturing. In this study, testing has been carried out using LUT combined with the synthetic aperture focusing technique (SAFT) on 25 and 50mm thick butt welded joints of steel both completed and partially welded. EDM slits of 2 or 3mm height were inserted at different depths in the multi-pass welding process to simulate a lack of fusion. Line scans transverse to the weld are performed with the generation and detection laser spots superimposed directly on the surface of the weld bead. A CCD line camera is used to simultaneously acquire the surface profile for correction in the SAFT processing. All artificial defects but also real defects are visualized in the investigated thick butt weld specimens, either completed or partially welded after a given number of passes. The results obtained clearly show the potential of using the LUT with SAFT for the automated inspection of arc welds or hybrid laser-arc welds during manufacturing.

  6. MODELLING AND CHARACTERIZATION OF LASER WELDED INCOLOY 800 HT JOINTS

    Directory of Open Access Journals (Sweden)

    Sathiya Paulraj

    2016-06-01

    Full Text Available This study aims at finding the effect of laser welding speed on incoloy 800 HT. This alloy is one of the potential materials for Generation IV nuclear plants. Laser welding has several advantages over arc welding such as low fusion zone, low heat input and concentrated heat intensity. Three different welding speeds were chosen and CO2 laser welding was performed. 2D modeling and simulation were done using ANSYS 15 to find out the temperature distribution at different welding speeds and it was found that an increase in the welding speed decreased the temperature. Mechanical properties such as tensile strength, toughness and hardness were evaluated. The effect of welding speed on metallurgical characteristics was studied using optical microscopy (OM, Scanning Electron Microscopy (SEM with EDS, X-Ray Diffraction (XRD technique and fractographic analysis. From the results it was found that high welding speed (1400 mm/min decreased the joint strength. The M23C6 and Ni3Ti carbides were formed in a discrete chain and in a globular form along the grain boundaries of the weld region which increased the strength of the grain boundaries. Fractographic evaluations of the tested specimens for welding speed (1000 and 1200 mm/min showed deep and wide dimples indicating ductile failures.

  7. Mechanical properties of thin films of laser-welded titanium and their associated welding defects.

    Science.gov (United States)

    Wu, Yulu; Xin, Haitao; Zhang, Chunbao; Tang, Zhongbin; Zhang, Zhiyuan; Wang, Weifeng

    2014-11-01

    The aim of this study was to evaluate the mechanical properties of thin films of laser-welded cast titanium using an interference strain/displacement gauge (ISDG) and to analyze factors that affect laser welding. Dog-bone-shaped small specimens of cast titanium were prepared by wire cutting after they were laser-welded. The specimens were divided into three groups according to the gap distance of the laser weld; the control was non-welded titanium. Small specimens without cast defects detected by X-ray screening were measured by a tensile test machine using ISDG, and stress-strain curves were drawn. Finally, the fracture texture was analyzed. The ultimate tensile strengths (UTSs) of specimens with a gap distance of 0.00, 0.25, and 0.50 mm were 492.16 ± 33.19, 488.09 ± 43.18, and 558.45 ± 10.80 MPa, respectively. There were no significant differences in UTS between the test groups and the control group (p > 0.05). However, the plastic deformation and the percent elongation increased as the gap distance increased. Incomplete penetration defects appeared in groups that had small gap distances, which may have affected the properties of the laser-welded titanium. However, the welding material was still pure titanium. These results suggest that an appropriate gap distance should be maintained to improve the application of dental laser welding.

  8. Residual stress analysis of an Overlay weld and a repair weld on the dissimilar Butt weld

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kang Soo, E-mail: kskim5@kaeri.re.k [Korea Atomic Energy Research Institute, 150, Dukjin-dong, Daejeon 305-353 (Korea, Republic of); Lee, Ho Jin; Lee, Bong Sang [Korea Atomic Energy Research Institute, 150, Dukjin-dong, Daejeon 305-353 (Korea, Republic of); Jung, In Chul; Park, Kwang Soo [Doosan Heavy Industries and Construction Co., 555 Gwigok Dong, Changwon 641-792 (Korea, Republic of)

    2009-12-15

    Both the experiment and FE analysis were performed to estimate the residual stresses at the parts of the dissimilar metal welds. The specimen of the dissimilar Butt welds was manufactured, and the residual stresses of this specimen were measured by the X-ray method and a Hole Drilling Technique. The values measured by two experimental methods showed a big deviation at the SUS 316L plate. Consequently, the experimental methods to estimate the residual stresses are not a superior method. The Butt FEM Model on this specimen was developed and analyzed by the ABAQUS Code. The results of the FE analysis were compared with those of the experimental methods. As a whole, the values of the Butt FEM Model showed a trend which was in agreement with the experimental values and the values of FE analysis were found reasonable. The Repair FEM Model and the Overlay FEM Model were developed and analyzed by the ABAQUS Code. The values of these results were also found reasonable data even if the experimental methods be not performed. Therefore, the residual stresses for the dissimilar metal welds can be estimated by an analysis with an appropriate FEM Model without the experimental methods.

  9. Application of Taguchi approach to optimize friction stir welding parameters of polyethylene

    Directory of Open Access Journals (Sweden)

    Bejaoui S.

    2010-06-01

    Full Text Available This paper presents experimental and numerical results of butt friction stir welding of high density polyethylene. The FSW designed tool insulates the welded samples and preserves the heat gained from friction thus avoiding the appearance of blisters and splits after welding. The experimental tests, conducted according to combinations of process factors such as rotation speed, welding speed, pin diameter and hold time at beginning welding, were carried out according the Taguchi orthogonal table L27 in randomized way. Temperatures in the joint during the welding operation and flow stresses from the tensile tests of welded samples were measured and variances were analyzed. Identified models were used to simulate, by finite elements, the tensile tests performed on specimens having a weld cordon in their active area. The results show coherence between the numerical predictions and experimental observations in different cases of weld cordon mechanical behaviour.

  10. Application of Taguchi approach to optimize friction stir welding parameters of polyethylene

    Science.gov (United States)

    Rezgui, M. A.; Ayadi, M.; Cherouat, A.; Hamrouni, K.; Zghal, A.; Bejaoui, S.

    2010-06-01

    This paper presents experimental and numerical results of butt friction stir welding of high density polyethylene. The FSW designed tool insulates the welded samples and preserves the heat gained from friction thus avoiding the appearance of blisters and splits after welding. The experimental tests, conducted according to combinations of process factors such as rotation speed, welding speed, pin diameter and hold time at beginning welding, were carried out according the Taguchi orthogonal table L27 in randomized way. Temperatures in the joint during the welding operation and flow stresses from the tensile tests of welded samples were measured and variances were analyzed. Identified models were used to simulate, by finite elements, the tensile tests performed on specimens having a weld cordon in their active area. The results show coherence between the numerical predictions and experimental observations in different cases of weld cordon mechanical behaviour.

  11. Welding processes handbook

    CERN Document Server

    Weman, Klas

    2011-01-01

    Offers an introduction to the range of available welding technologies. This title includes chapters on individual techniques that cover principles, equipment, consumables and key quality issues. It includes material on such topics as the basics of electricity in welding, arc physics, and distortion, and the weldability of particular metals.$bThe first edition of Welding processes handbook established itself as a standard introduction and guide to the main welding technologies and their applications. This new edition has been substantially revised and extended to reflect the latest developments. After an initial introduction, the book first reviews gas welding before discussing the fundamentals of arc welding, including arc physics and power sources. It then discusses the range of arc welding techniques including TIG, plasma, MIG/MAG, MMA and submerged arc welding. Further chapters cover a range of other important welding technologies such as resistance and laser welding, as well as the use of welding techniqu...

  12. Friction Stir Welding

    Science.gov (United States)

    Nunes, Arthur C., Jr.

    2008-01-01

    Friction stir welding (FSW) is a solid state welding process invented in 1991 at The Welding Institute in the United Kingdom. A weld is made in the FSW process by translating a rotating pin along a weld seam so as to stir the sides of the seam together. FSW avoids deleterious effects inherent in melting and promises to be an important welding process for any industries where welds of optimal quality are demanded. This article provides an introduction to the FSW process. The chief concern is the physical effect of the tool on the weld metal: how weld seam bonding takes place, what kind of weld structure is generated, potential problems, possible defects for example, and implications for process parameters and tool design. Weld properties are determined by structure, and the structure of friction stir welds is determined by the weld metal flow field in the vicinity of the weld tool. Metal flow in the vicinity of the weld tool is explained through a simple kinematic flow model that decomposes the flow field into three basic component flows: a uniform translation, a rotating solid cylinder, and a ring vortex encircling the tool. The flow components, superposed to construct the flow model, can be related to particular aspects of weld process parameters and tool design; they provide a bridge to an understanding of a complex-at-first-glance weld structure. Torques and forces are also discussed. Some simple mathematical models of structural aspects, torques, and forces are included.

  13. The influence of the weld toe grinding and wig remelting weld toe rehabilitation techniques, on variable stresses, in case of cross fillet welds, reinforced with additional welding rows

    Directory of Open Access Journals (Sweden)

    Babis Claudiu

    2017-01-01

    Full Text Available Variable stresses where the load value varies between a maximum and a minimum value, or varies the position in time, cause after accumulating a large number of load cycles in those structures, the emergence of drug fatigue. Fatigue is characterized by failure on values of the applied stress from the load cycles, below the material flow, values which in case of static stress would not have caused problems. Knowing that the variable stressed structures are sensitive to stress concentrators, the paper aims to highlight the influence of two techniques to reduce stress concentrator weld toe grinding and WIG remelting weld toe, on the behavior of variable tensile test of cross corner welded specimens, reinforced with additional welding rows.

  14. The ultrasonic testing of the spot welded different steel sheets

    Directory of Open Access Journals (Sweden)

    M. Vural

    2006-08-01

    Full Text Available Purpose: Purpose of this paper is to investigate the applicability of spot welded different steel sheets toultrasonic testing, because resistance spot welding of the steel sheets is widely used in the car bodies andtransport fields and ultrasonic testing is a good way to evaluate the fatique life of the spot welds.Design/methodology/approach: Methodology of this paper is that two different steel sheets (AISI 304 typeaustenitic stainless steel sheet and Galvanized steel sheet were welded to each other by using resistance spotwelding. Some pre-welding tests were made to obtain suitable and optimum weld nugget diameter; and thewelding current vs. nugget diameter curve were obtained. By using this curve and kepting constant weldingparameters such as current, electrode pressure, weld time, etch., fully identical four spot welded specimenshaving 5 mm (±0.2 nugget diameter were obtained. The specimens and nugget diameters were tested by usinga special ultrasonic test apparatus which is designed for spot welded joints.Findings: Findings are that after the first ultrasonic tests, the four identical spot welded sheets which have AISI304 – Galvanized steel sheet combination were subjected to the fatigue test in four different number of cycles.There is no any rupture or fracture in spot welded joints after fatigue tests. The spot welded specimens subjectedto fatigue test were tested in ultrasonic test apparatus to observe the variation in the weld nugget and joint. Theultrasonic test results before fatigue and after fatigue were compared with each other; and the decreasing of theweld nugget diameter were observed while increasing the number of cycles. The results were shown in figuresand discussed.Research limitations/implications: Spot welding of different steel sheets forms different microstructures whichrespond different values to ultrasonic testing. Evaluation of these responses are quiet difficult.Practical implications: Only a few spot welds can be

  15. Fatigue Analysis of Load-Carrying Fillet Welds

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Tychsen, Jesper; Andersen, Jens Ulfkjær

    2006-01-01

    is a doubler plate connection, which is often applied in connection with modifications of offshore structures. As a part of the present work, fatigue tests have been performed with test specimens fabricated by the current industry standard for welded offshore steel structures. The fatigue tests show......The fatigue strength of load-carrying fillet welds is, in most codes of practice, performed neglecting the influence of bending in the weld throat section. However, some commonly applied structural details give rise to significant bending in the weld throat section. An example of such a detail...... that the degree of bending (DOB) has an influence on the fatigue lifetime. The fatigue lifetime decreases significantly when increasing the bending stress. In order to take into account the effect of the bending, a new fatigue stress definition applicable for fillet welds failing through the weld is presented...

  16. Urine culture - catheterized specimen

    Science.gov (United States)

    Culture - urine - catheterized specimen; Urine culture - catheterization; Catheterized urine specimen culture ... urinary tract infections may be found in the culture. This is called a contaminant. You may not ...

  17. Distortion Control during Welding

    NARCIS (Netherlands)

    Akbari Pazooki, A.M.

    2014-01-01

    The local material expansion and contraction involved in welding result in permanent deformations or instability i.e., welding distortion. Considerable efforts have been made in controlling welding distortion prior to, during or after welding. Thermal Tensioning (TT) describes a group of in-situ met

  18. Introduction to Welding.

    Science.gov (United States)

    Fortney, Clarence; Gregory, Mike

    This curriculum guide provides six units of instruction on basic welding. Addressed in the individual units of instruction are the following topics: employment opportunities for welders, welding safety and first aid, welding tools and equipment, basic metals and metallurgy, basic math and measuring, and procedures for applying for a welding job.…

  19. Development of Alternative Technology to PWHT in Site Welding

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Jin; Lee, B. S.; Jang, J. S.; Kim, K. H.; Park, S. D.; Yoon, J. H.; Kim, M. C.; Kim, K. B.; Sung, K. W

    2007-04-15

    ASME Section IX added requirements for qualification when using temper bead welding in the 2004 edition. The temper bead welding techniques which can satisfy the requirements of the Code are needed to use them in the site repair welding. The optimized welding parameters can be obtained when controlling the process to supercritically-reheat and to subcritically-reheat the coarse grain region sequently. The microstructures of SCFGCG obtained from the Gleegle simulated specimens and those of post weld heat treated coarse grain region are compared. The obtained both microstructures showed almost similar patterns. mid bead deposition technique Suggested in this study has a technical concept that the mid beads are deposited between the deposited initial beads repeatedly in a bead layer, which gives a lot of reheating effects on brittle microstructure in HAZ. This newly suggested technique is considered to have more effective tempering effect than the conventional temper bead technique which has concept to deposit one type of beads in a bead layer. The suggested modeling in this study can simulate well the SMAW process. Hence this modeling was used in analyzing the more complicated welding process of multi-layer welding. The modeling was used to analyze the tempering effect on the microstructures of HAZ by considering the patterns of overlapping of the reheating regions under the consequently deposited beads. When considering the crack path in the ever-matched weld metal condition, the interface may have a resistance against the crack propagation. A182 filler and A625 filler were used to make the weld specimens which have different weld metal conditions. The crack directed toward the under-matched weld metal may propagate across the fusion line easier than that of the even-matched weld metal condition.

  20. Nucleus geometry and mechanical properties of resistance spot welded coated–uncoated DP automotive steels

    Indian Academy of Sciences (India)

    Ibrahim Sevim; Fatih Hayat; Mustafa Kemal Kulekci

    2013-11-01

    In this study, mechanical properties of resistance spot welding of DP450 and DP600, galvanized and ungalvanized automotive sheets have been investigated. The specimens have been joined by resistance spot welding at different weld currents and times. Welded specimens have been examined for their mechanical, macrostructure and microstructure properties. Depending on the weld current and time, effects of zinc coating on tensile properties, microhardness values as well as microstructure nugget geometry and nucleus size ratio have been investigated. X-ray diffraction analysis has been used to investigate the phase that formed at the joint interface. Result of the experiment show that nugget diameter, indentation depth and tensile load-bearing capacity are affected by weld parameters. Coating prevents full joining at low parameters. Microhardness increased in heat-affected zone and weld metal.

  1. Welding Characteristics of Ultrasonic Wire Bonding Using High-Frequency Vibration Systems

    Science.gov (United States)

    Tsujino, Jiromaru; Mori, Takahiro; Hasegawa, Koichi

    1994-05-01

    Welding characteristics of ultrasonic wire bonding using 60 kHz, 90 kHz and 120 kHz complex vibration as well as 190 kHz linear vibration welding systems are studied. The locus shapes of the complex vibration welding tip are controlled from linear to elliptical or circular. Aluminum wire specimens of 0.1 mm diameter are welded successfully using complex and high-frequency welding equipment. The required vibration amplitudes of these complex vibration systems are about one-half to one-third and required weld time is shorter than those of a conventional system of linear vibration. The required vibration velocity of a high-frequency system is lower than that of a low-frequency system. The deformations of the welded specimens under adequate welding conditions are almost the same, even if the welding tip vibration locus is altered from linear to elliptical or circular, or the vibration frequency used is changed from 60 kHz to 190 kHz in the case where the same wire specimens are used. Using these methods, the weld strength of wire bonding becomes independent of the difference in the directions of the welding tip vibration and wire length.

  2. Joint performance of CO2 laser beam welding 5083-H321 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Qi Junfeng; Zhang Dongyun; Xiao Rongshi; Chen Kai; Zuo Tiechuan

    2007-01-01

    Laser beam welding of aluminum alloys is expected to offer good mechanical properties of welded joints. In this experimental work reported, CO2 laser beam autogenous welding and wire feed welding are conducted on 4mm thick 5083-H321 aluminum alloy sheets at different welding variables. The mechanical properties and microstructure characteristics of the welds are evaluated through tensile tests, micro-hardness tests, optical microscopy and scanning electron microscopy (SEM). Experimental results indicate that both the tensile strength and hardness of laser beam welds are affected by the constitution of filler material, except the yield strength. The soften region of laser beam welds is not in the heat-affected zone (HAZ). The tensile fracture of laser beam welded specimens takes place in the weld zone and close to the weld boundary because of different filler materials. Some pores are found on the fracture face, including hydrogen porosities and blow holes, but these pores have no influence on the tensile strength of laser beam welds. Tensile strength values of laser beam welds with filler wire are up to 345.57MPa, 93% of base material values, and yield strengths of laser beam welds are equivalent to those of base metal (264.50MPa).

  3. MICROSTRUCTURE AND FATIGUE PROPERTIES OF DISSIMILAR SPOT WELDED JOINTS OF AISI 304 AND AISI 1008

    Directory of Open Access Journals (Sweden)

    Nachimani Charde

    2013-06-01

    Full Text Available Carbon steel and stainless steel composites are being more frequently used for applications requiring a corrosion resistant and attractive exterior surface and a high strength structural substrate. Spot welding is a potentially useful and efficient jointing process for the production of components consisting of these two materials. The spot welding characteristics of weld joints between these two materials are discussed in this paper. The experiment was conducted on dissimilar weld joints using carbon steel and 304L (2B austenitic stainless steel by varying the welding currents and electrode pressing forces. Throughout the welding process; the electrical signals from the strain sensor, current transducer and terminal voltage clippers are measured in order to understand each and every millisecond of the welding process. In doing so, the dynamic resistances, heat distributions and forging forces are computed for various currents and force levels within the good welds’ regions. The other process controlling parameters, particularly the electrode tip and weld time, remained constant throughout the experiment. The weld growth was noted for the welding current increment, but in the electrode force increment it causes an adverse reaction to weld growth. Moreover, the effect of heat imbalance was clearly noted during the welding process due to the different electrical and chemical properties. The welded specimens finally underwent tensile, hardness and metallurgical testing to characterise the weld growth.

  4. Microhardness Testing of Aluminum Alloy Welds

    Science.gov (United States)

    Bohanon, Catherine

    2009-01-01

    A weld is made when two pieces of metal are united or fused together using heat or pressure, and sometimes both. There are several different types of welds, each having their own unique properties and microstructure. Strength is a property normally used in deciding which kind of weld is suitable for a certain metal or joint. Depending on the weld process used and the heat required for that process, the weld and the heat-affected zone undergo microstructural changes resulting in stronger or weaker areas. The heat-affected zone (HAZ) is the region that has experienced enough heat to cause solid-state microstructural changes, but not enough to melt the material. This area is located between the parent material and the weld, with the grain structure growing as it progresses respectively. The optimal weld would have a short HAZ and a small fluctuation in strength from parent metal to weld. To determine the strength of the weld and decide whether it is suitable for the specific joint certain properties are looked at, among these are ultimate tensile strength, 0.2% offset yield strength and hardness. Ultimate tensile strength gives the maximum load the metal can stand while the offset yield strength gives the amount of stress the metal can take before it is 0.2% longer than it was originally. Both of these are good tests, but they both require breaking or deforming the sample in some way. Hardness testing, however, provides an objective evaluation of weld strengths, and also the difference or variation in strength across the weld and HAZ which is difficult to do with tensile testing. Hardness is the resistance to permanent or plastic deformation and can be taken at any desired point on the specimen. With hardness testing, it is possible to test from parent metal to weld and see the difference in strength as you progress from parent material to weld. Hardness around grain boundaries and flaws in the material will show how these affect the strength of the metal while still

  5. Advanced Welding Applications

    Science.gov (United States)

    Ding, Robert J.

    2010-01-01

    Some of the applications of advanced welding techniques are shown in this poster presentation. Included are brief explanations of the use on the Ares I and Ares V launch vehicle and on the Space Shuttle Launch vehicle. Also included are microstructural views from four advanced welding techniques: Variable Polarity Plasma Arc (VPPA) weld (fusion), self-reacting friction stir welding (SR-FSW), conventional FSW, and Tube Socket Weld (TSW) on aluminum.

  6. Influence of Friction Stir Welding (FSW) on Mechanical and Corrosion Properties of AW-7020M and Aw-7020 Alloys

    OpenAIRE

    Dudzik Krzysztof; Jurczak Wojciech

    2016-01-01

    Friction welding associated with mixing the weld material (FSW - Friction Stir Welding ) is an alternative to MIG and TIG welding techniques for Al-alloys. This paper presents experimental results obtained from static tension tests on specimens made of AW-7020M and AW-7020 alloys and their joints welded by using FSW method carried out on flat specimens, according to Polish standards : PN-EN ISO 4136:2011 and PN-EN ISO 6892-1:2010. Results of corrosion resistance tests are also presented. The ...

  7. Residual Stress and Fatigue Strength of Hybrid Laser-MIG-Welded A7N01P-T4

    Science.gov (United States)

    Wang, Qiuying; Chen, Hui; Qiu, Peixian; Zhu, Zongtao

    2017-02-01

    A7N01P-T4 aluminum alloy is widely used in some important welded components of high-speed trains. The hybrid laser-metal inert gas (MIG) welding process was studied to solve problems associated with the MIG welding process, such as low welding efficiency, high residual stress and deformation, and serious loss of strength. A high-speed camera, a voltage and current collection system, and NI DAQ were used to acquire arc profiles, welding voltage, and welding current simultaneously. Thermal cycle tests were carried out. Residual stresses induced by the welding process and fatigue strength of the joint were investigated. Large-size fatigue specimens were used in fatigue tests. The results show that the energy of the hybrid welding process is focused, and the power density of hybrid welding process is intense. The heat input per unit of the hybrid welding process is only half of that of the MIG welding process. Compared with the MIG welded joint, the overall residual stress level of the hybrid-welded joint is lower. The peak longitudinal stress of the hybrid-welded joint is reduced by 20 pct. The fatigue strength of hybrid joints is 14 pct higher than that of MIG-welded joints. Narrow weld and HAZ, weak softening behavior, and low residual stress level are the causes of the improvement of fatigue strength.

  8. Residual Stress and Fatigue Strength of Hybrid Laser-MIG-Welded A7N01P-T4

    Science.gov (United States)

    Wang, Qiuying; Chen, Hui; Qiu, Peixian; Zhu, Zongtao

    2016-09-01

    A7N01P-T4 aluminum alloy is widely used in some important welded components of high-speed trains. The hybrid laser-metal inert gas (MIG) welding process was studied to solve problems associated with the MIG welding process, such as low welding efficiency, high residual stress and deformation, and serious loss of strength. A high-speed camera, a voltage and current collection system, and NI DAQ were used to acquire arc profiles, welding voltage, and welding current simultaneously. Thermal cycle tests were carried out. Residual stresses induced by the welding process and fatigue strength of the joint were investigated. Large-size fatigue specimens were used in fatigue tests. The results show that the energy of the hybrid welding process is focused, and the power density of hybrid welding process is intense. The heat input per unit of the hybrid welding process is only half of that of the MIG welding process. Compared with the MIG welded joint, the overall residual stress level of the hybrid-welded joint is lower. The peak longitudinal stress of the hybrid-welded joint is reduced by 20 pct. The fatigue strength of hybrid joints is 14 pct higher than that of MIG-welded joints. Narrow weld and HAZ, weak softening behavior, and low residual stress level are the causes of the improvement of fatigue strength.

  9. Comparative study of TIG and SMAW root welding passes on ductile iron cast weldability

    Directory of Open Access Journals (Sweden)

    J. Cárcel-Carrasco

    2017-01-01

    Full Text Available This work compares the weldability of ductile iron when: (I a root weld is applied with a tungsten inert gas (TIG process using an Inconel 625 source rod and filler welds are subsequently applied using coated electrodes with 97,6%Ni; and (II welds on ductile iron exclusively made using the manual shielded metal arc welding technique (SMAW. Both types of welds are performed on ductile iron specimen test plates that are subjected to preheat and post-weld annealing treatments. Samples with TIG root-welding pass shown higher hardness but slightly lower ductility and strength. Both types of welding achieved better ductile and strength properties than ones found in literature.

  10. Evaluation of the AISI 904L Alloy Weld Overlays Obtained by GMAW and Electro-Slag Welding Processes

    Science.gov (United States)

    Jorge, Jorge C. F.; Meira, O. G.; Madalena, F. C. A.; de Souza, L. F. G.; Araujo, L. S.; Mendes, M. C.

    2017-03-01

    findings, the hardness results for ESW were lower than those usually observed for other electric arc welding processes. In addition, specimens subject to bending tests performed in accordance with the current standards used for qualification of welding procedures were approved. These evidences allow the conclusion that the ESW process can provide deposits with high quality despite the high welding energy levels, in order to achieve the desired productivity, being an interesting alternative for AISI 904L weld overlays.

  11. Evaluation of the AISI 904L Alloy Weld Overlays Obtained by GMAW and Electro-Slag Welding Processes

    Science.gov (United States)

    Jorge, Jorge C. F.; Meira, O. G.; Madalena, F. C. A.; de Souza, L. F. G.; Araujo, L. S.; Mendes, M. C.

    2017-05-01

    findings, the hardness results for ESW were lower than those usually observed for other electric arc welding processes. In addition, specimens subject to bending tests performed in accordance with the current standards used for qualification of welding procedures were approved. These evidences allow the conclusion that the ESW process can provide deposits with high quality despite the high welding energy levels, in order to achieve the desired productivity, being an interesting alternative for AISI 904L weld overlays.

  12. Deflection load characteristics of laser-welded orthodontic wires.

    Science.gov (United States)

    Watanabe, Etsuko; Stigall, Garrett; Elshahawy, Waleed; Watanabe, Ikuya

    2012-07-01

    To compare the deflection load characteristics of homogeneous and heterogeneous joints made by laser welding using various types of orthodontic wires. Four kinds of straight orthodontic rectangular wires (0.017 inch × 0.025 inch) were used: stainless-steel (SS), cobalt-chromium-nickel (Co-Cr-Ni), beta-titanium alloy (β-Ti), and nickel-titanium (Ni-Ti). Homogeneous and heterogeneous end-to-end joints (12 mm long each) were made by Nd:YAG laser welding. Two types of welding methods were used: two-point welding and four-point welding. Nonwelded wires were also used as a control. Deflection load (N) was measured by conducting the three-point bending test. The data (n  =  5) were statistically analyzed using analysis of variance/Tukey test (P welded specimens showed lower deflection loads compared to corresponding control wires and exhibited higher deflection loads compared to heterogeneously welded combinations. For homogeneous combinations, Co-Cr-Ni/Co-Cr-Ni showed a significantly (P welded groups. In heterogeneous combinations, SS/Co-Cr-Ni and β-Ti/Ni-Ti showed higher deflection loads than those of the remaining heterogeneously welded combinations (significantly higher for SS/Co-Cr-Ni). Significance (P welding method). However, no significant difference in deflection load was found between four-point and two-point welding in each homogeneous or heterogeneous combination. Heterogeneously laser-welded SS/Co-Cr-Ni and β-Ti/Ni-Ti wires provide a deflection load that is comparable to that of homogeneously welded orthodontic wires.

  13. Joining characteristics of orthodontic wires with laser welding.

    Science.gov (United States)

    Iijima, Masahiro; Brantley, William A; Yuasa, Toshihiro; Muguruma, Takeshi; Kawashima, Isao; Mizoguchi, Itaru

    2008-01-01

    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 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.

  14. Welded solar cell interconnection

    Science.gov (United States)

    Stofel, E. J.; Browne, E. R.; Meese, R. A.; Vendura, G. J.

    1982-01-01

    The efficiency of the welding of solar-cell interconnects is compared with the efficiency of soldering such interconnects, and the cases in which welding may be superior are examined. Emphasis is placed on ultrasonic welding; attention is given to the solar-cell welding machine, the application of the welding process to different solar-cell configurations, producibility, and long-life performance of welded interconnects. Much of the present work has been directed toward providing increased confidence in the reliability of welding using conditions approximating those that would occur with large-scale array production. It is concluded that there is as yet insufficient data to determine which of three methods (soldering, parallel gap welding, and ultrasonic welding) provides the longest-duration solar panel life.

  15. Numerical aspects for efficient welding computational mechanics

    Directory of Open Access Journals (Sweden)

    Aburuga Tarek Kh.S.

    2014-01-01

    Full Text Available The effect of the residual stresses and strains is one of the most important parameter in the structure integrity assessment. A finite element model is constructed in order to simulate the multi passes mismatched submerged arc welding SAW which used in the welded tensile test specimen. Sequentially coupled thermal mechanical analysis is done by using ABAQUS software for calculating the residual stresses and distortion due to welding. In this work, three main issues were studied in order to reduce the time consuming during welding simulation which is the major problem in the computational welding mechanics (CWM. The first issue is dimensionality of the problem. Both two- and three-dimensional models are constructed for the same analysis type, shell element for two dimension simulation shows good performance comparing with brick element. The conventional method to calculate residual stress is by using implicit scheme that because of the welding and cooling time is relatively high. In this work, the author shows that it could use the explicit scheme with the mass scaling technique, and time consuming during the analysis will be reduced very efficiently. By using this new technique, it will be possible to simulate relatively large three dimensional structures.

  16. Optimal welding of beta titanium orthodontic wires.

    Science.gov (United States)

    Nelson, K R; Burstone, C J; Goldberg, A J

    1987-09-01

    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.

  17. Electrochemical Testing of Gas Tungsten ARC Welded and Reduced Pressure Electron Beam Welded Alloy 22

    Energy Technology Data Exchange (ETDEWEB)

    S. Daniel Day; Frank M.G. Wong; Steven R. Gordon; Lana L. Wong; Raul B. Rebak

    2006-05-08

    Alloy 22 (N06022) is the material selected for the fabrication of the outer shell of the nuclear waste containers for the Yucca Mountain high-level nuclear waste repository site. A key technical issue in the waste package program has been the integrity of the container weld joints. The currently selected welding process for fabricating and sealing the containers is the traditional gas tungsten arc welding (GTAW) or TIC method. An appealing faster alternative technique is reduced pressure electron beam (RPEB) welding. It was of interest to compare the corrosion properties of specimens prepared using both types of welding techniques. Standard electrochemical tests were carried on GTAW and RPEB welds as well as on base metal (non-welded) to determine their relative corrosion behavior in simulated concentrated water (SCW) at 90 C (alkaline), 1 M HCI at 60 C (acidic) and 1 M NaCl at 90 C (neutral) solutions. Results show that for all practical purposes, the three tested materials had the same electrochemical behavior in the three tested electrolytes.

  18. Handbook of Plastic Welding

    DEFF Research Database (Denmark)

    Islam, Aminul

    The purpose of this document is to summarize the information about the laser welding of plastic. Laser welding is a matured process nevertheless laser welding of micro dimensional plastic parts is still a big challenge. This report collects the latest information about the laser welding of plasti...... as a knowledge handbook for laser welding of plastic components. This document should provide the information for all aspects of plastic laser welding and help the design engineers to take all critical issues into consideration from the very beginning of the design phase....

  19. An investigation of the microstructures and properties of metal inert gas and friction stir welds in aluminum alloy 5083

    Indian Academy of Sciences (India)

    A R Yazdipour; A Shafiei M; H Jamshidi Aval

    2011-08-01

    Two different types of welds, Metal Inert Gas (MIG) and Friction Stir Welding (FSW), have been used to weld aluminum alloy 5083. The microstructure of the welds, including the nugget zone and heat affected zone, has been compared in these two methods using optical microscopy. The mechanical properties of the weld have been also investigated using the hardness and tensile tests. The results show that both the methods could successfully be used to weld such alloy. The strength of the joints is comparable to the strength of the base metal in both cases. However, FSWed samples have shown higher strength in comparison to the MIG samples. The results also show that the extension of the heat affected zone is higher in the MIG method in comparison to the FSW method. The weld metal microstructure of MIG welded specimen contains equiaxed dendrites as a result of solidification process during MIG welding while FSWed samples have wrought microstructures.

  20. Hydrogen Cracking in Gas Tungsten Arc Welding of an AISI Type 321 Stainless Steel

    Science.gov (United States)

    Rozenak, P.; Unigovski, Ya.; Shneck, R.

    The effects of in situ cathodic charging on the tensile properties and susceptibility to cracking of an AISI type 321 stainless steel, welded by the gas tungsten arc welding (GTAW) process, was studied by various treatments. Appearance of delta-ferrite phase in the as-welded steels in our tested conditions was observed with discontinuous grain boundaries (M23C6) and a dense distribution of metal carbides MC ((Ti, Nb)C), which precipitated in the matrix. Shielding gas rates changes the mechanical properties of the welds. Ultimate tensile strength and ductility are increases with the resistance to the environments related the increase of the supplied shielding inert gas rates. Charged specimens, caused mainly in decreases in the ductility of welded specimens. However, more severe decrease in ductility was obtained after post weld heat treatment (PWHT). The fracture of sensitized specimens was predominantly intergranular, whereas the as-welded specimens exhibited massive transgranular regions. Both types of specimen demonstrated narrow brittle zones at the sides of the fracture surface and ductile micro-void coalescences in the middle. Ferrite δ was form after welding with high density of dislocation structures and stacking faults formation and the thin stacking fault plates with e-martensite phase were typically found in the austenitic matrix after the cathodical charging process.

  1. Modeling cast IN-738 superalloy gas tungsten arc welds

    Energy Technology Data Exchange (ETDEWEB)

    Bonifaz, E.A. [Department of Mechanical and Manufacturing Engineering, University of Manitoba, E2-327F EITC, Winnipeg, Man., R3T 5V6 (Canada); Universidad San Francisco de Quito, Casilla Postal: 17-12-841 Circulo de Cumbaya, Quito (Ecuador)], E-mail: bonifaz@cc.umanitoba.ca; Richards, N.L. [Department of Mechanical and Manufacturing Engineering, University of Manitoba, E2-327F EITC, Winnipeg, Man., R3T 5V6 (Canada)], E-mail: nrichar@cc.umanitoba.ca

    2009-04-15

    A three-dimensional finite-element thermal model has been developed to generate weld profiles, and to analyze transient heat flow, thermal gradients and thermal cycles in cast IN-738 superalloy gas tungsten arc welds. Outputs of the model (cooling rates, the thermal gradient G and the growth rate R) were used to describe solidification structures found around the weld pool for three different welding speeds at constant heat input. Calculations around the weld pool indicate that the cooling rate increases from the fusion line to the centerline at all welding speeds. It was also observed that the cooling rate (G x R) and the ratio G/R fall with welding speed. For instance, as the welding speed is increased, the cooling rates at the centerline, fusion line and penetration depth decrease. Moreover, it was observed that as the power and welding speed both increase (but keeping the heat input constant), the weld pool becomes wider and more elongated, shifting from circular to elliptical shaped. The calculations were performed using ABAQUS FE code on the basis of a time-increment Lagrangian formulation. The heat source represented by a moving Gaussian power density distribution is applied over the top surface of the specimen during a period of time that depends on the welding speed. Temperature-dependent material properties and the effect of forced convection due to the flow of the shielding gas are included in the model. Numerically predicted sizes of the melt-pool zone and dendrite secondary arm spacing induced by the gas tungsten arc welding process are also given.

  2. Corrosion Resistance of Synergistic Welding Process of Aluminium Alloy 6061 T6 in Sea Water

    Directory of Open Access Journals (Sweden)

    Kharia Salman Hassan

    2014-12-01

    Full Text Available This work involves studying corrosion resistance of AA 6061T6 butt welded joints using Two different welding processes, tungsten inert gas (TIG and a solid state welding process known as friction stir welding, TIG welding process carried out by using Rolled sheet of thickness6mm to obtain a weld joint with dimension of (100, 50, 5 mm using ER4043 DE (Al Si5 as filler metal and argon as shielding gas, while Friction stir welding process carried out using CNC milling machine with a tool of rotational speed 1000 rpm and welding speed of 50mm/min to obtain the same butt joint dimensions. Also one of weld joint in the same dimensions subjected to synergistic weld process TIG and FSW weld process at the same previous weld conditions. All welded joints were tested by X-ray radiography and Faulty pieces were excluded. The joints without defects used to prepare many specimens for Corrosion test by the dimensions of (15*15*3 mm according to ASTM G71-31. Specimens subjected to micro hardness and microstructure test. Corrosion test was achieved by potential at scan rate( +1000 ,-1000mv/sec to estimate corrosion parameters by extrapolator Tafle method after polarized ±100 mv around open circuit potential,in seawater (3.5%NaCl at a temperature of 25°C. From result which obtained by Tafel equation. It was found that corrosion rate for TIG weld joint was higher than the others but synergistic weld process contributed in improving TIG corrosion resistance by a percentage of 14.3%. and FSW give the lest corrosion rate comparing with base metal.

  3. Plasma spot welding of ferritic stainless steels

    Directory of Open Access Journals (Sweden)

    Lešnjak, A.

    2002-06-01

    Full Text Available Plasma spot welding of ferritic stainless steels is studied. The study was focused on welding parameters, plasma and shielding gases and the optimum welding equipment. Plasma-spot welded overlap joints on a 0.8 mm thick ferritic stainless steel sheet were subjected to a visual examination and mechanical testing in terms of tension-shear strength. Several macro specimens were prepared. Plasma spot welding is suitable to use the same gas as shielding gas and as plasma gas, i.e., a 98 % Ar/2 % H 2 gas mixture. Tension-shear strength of plasma-spot welded joints was compared to that of resistance-spot welded joints. It was found that the resistance welded joints withstand a somewhat stronger load than the plasma welded joints due to a larger weld spot diameter of the former. Strength of both types of welded joints is approximately the same.

    El artículo describe el proceso de soldeo de aceros inoxidables ferríticos por puntos con plasma. La investigación se centró en el establecimiento de los parámetros óptimos de la soldadura, la definición del gas de plasma y de protección más adecuado, así como del equipo óptimo para la realización de la soldadura. Las uniones de láminas de aceros inoxidables ferríticos de 0,8 mm de espesor, soldadas a solape por puntos con plasma, se inspeccionaron visualmente y se ensayaron mecánicamente mediante el ensayo de cizalladura por tracción. Se realizaron macro pulidos. Los resultados de la investigación demostraron que la solución más adecuada para el soldeo por puntos con plasma es elegir el mismo gas de plasma que de protección. Es decir, una mezcla de 98 % de argón y 2 % de hidrógeno. La resistencia a la cizalladura por tracción de las uniones soldadas por puntos con plasma fue comparada con la resistencia de las uniones soldadas por resistencia por puntos. Se llegó a la conclusión de que las uniones soldadas por resistencia soportan una carga algo mayor que la uniones

  4. Ultrasonic seam welding technologies of copper plate and tube for collecting solar energy

    Institute of Scientific and Technical Information of China (English)

    汤勇; 万珍平; 刘亚俊; 刘树道

    2003-01-01

    The ultrasonic welding is applied more and more extensively due to its advantages such as environmental protection, cleaning and energy saving. By researching the mechanism on ultrasonic seam welding of copper plates and tubes for collecting solar energy, it is put forward that the ultrasonic metal welding process can be divided into two stages, and two factors make functions jointly to join the welded metal specimens. In order to successfully join the welding, three basic conditions must be satisfied, that is, there should be high frequency friction vibration in the contact interface; pressure must be imposed on the plate specimen during friction vibration; the time of friction vibration and pressure imposed should be proper. Furthermore, how to select the hardness of copper plate and tube and ultrasonic seam welding parameters is analyzed by experiments.

  5. Comparing Laser Welding Technologies with Friction Stir Welding for Production of Aluminum Tailor-Welded Blanks

    Energy Technology Data Exchange (ETDEWEB)

    Hovanski, Yuri; Carsley, John; Carlson, Blair; Hartfield-Wunsch, Susan; Pilli, Siva Prasad

    2014-01-15

    A comparison of welding techniques was performed to determine the most effective method for producing aluminum tailor-welded blanks for high volume automotive applications. Aluminum sheet was joined with an emphasis on post weld formability, surface quality and weld speed. Comparative results from several laser based welding techniques along with friction stir welding are presented. The results of this study demonstrate a quantitative comparison of weld methodologies in preparing tailor-welded aluminum stampings for high volume production in the automotive industry. Evaluation of nearly a dozen welding variations ultimately led to down selecting a single process based on post-weld quality and performance.

  6. Coil Welding Aid

    Science.gov (United States)

    Wiesenbach, W. T.; Clark, M. C.

    1983-01-01

    Positioner holds coil inside cylinder during tack welding. Welding aid spaces turns of coil inside cylinder and applies contact pressure while coil is tack-welded to cylinder. Device facilitates fabrication of heat exchangers and other structures by eliminating hand-positioning and clamping of individual coil turns.

  7. Variable polarity arc welding

    Science.gov (United States)

    Bayless, E. O., Jr.

    1991-01-01

    Technological advances generate within themselves dissatisfactions that lead to further advances in a process. A series of advances in welding technology which culminated in the Variable Polarity Plasma Arc (VPPA) Welding Process and an advance instituted to overcome the latest dissatisfactions with the process: automated VPPA welding are described briefly.

  8. Welding Course Curriculum.

    Science.gov (United States)

    Genits, Joseph C.

    This guide is intended for use in helping students gain a fundamental background on the major aspects of the welding trade. The course emphasis is on mastery of the manipulative skills necessary to develop successful welding techniques and on acquisition of an understanding of the specialized tools and equipment used in welding. The first part…

  9. Instructional Guidelines. Welding.

    Science.gov (United States)

    Fordyce, H. L.; Doshier, Dale

    Using the standards of the American Welding Society and the American Society of Mechanical Engineers, this welding instructional guidelines manual presents a course of study in accordance with the current practices in industry. Intended for use in welding programs now practiced within the Federal Prison System, the phases of the program are…

  10. Effect of Post-Weld Heat Treatment on Mechanical and Electrochemical Properties of Gas Metal Arc-Welded 316L (X2CrNiMo 17-13-2) Stainless Steel

    Science.gov (United States)

    Muhammad, F.; Ahmad, A.; Farooq, A.; Haider, W.

    2016-10-01

    In the present research work, corrosion behavior of post-weld heat-treated (PWHT) AISI 316L (X2CrNiMo 17-13-2) specimens joined by gas metal arc welding is compared with as-welded samples by using potentiodynamic polarization technique. Welded samples were PWHT at 1323 K for 480 s and quenched. Mechanical properties, corrosion behavior and microstructures of as-welded and PWHT specimens were investigated. Microstructural studies have shown grain size refinement after PWHT. Ultimate tensile strength and yield strength were found maximum for PWHT samples. Bend test have shown that PWHT imparted ductility in welded sample. Fractographic analysis has evidenced ductile behavior for samples. Potentiodynamic polarization test was carried out in a solution composed of 1 M H2SO4 and 1 N NaCl. Corrosion rate of weld region was 127.6 mpy, but after PWHT, it was decreased to 13.12 mpy.

  11. The Cracking Induced by Oxidation-Hydriding in Welding Joints of Zircaloy-4 Plates

    Institute of Scientific and Technical Information of China (English)

    周邦新; 姚美意; 苗志; 李强; 刘文庆

    2003-01-01

    The welding joints of Zircaloy-4 plates obtained by diffusion welding at 800℃ under pressure in vacuum were cracked during autoclave tests at 400℃ superheated steam after exposure longer than 150 days. The section of specimens was examined by optical microscopy and the composition at the tips of cracking was analyzed by electron microprobe. The result shows that the combination of oxidation and hydriding induced cracking is responsible for this failure of the welding joints.

  12. Comparing Properties of Adhesive Bonding, Resistance Spot Welding, and Adhesive Weld Bonding of Coated and Uncoated DP 600 Steel%Comparing Properties of Adhesive Bonding, Resistance Spot Welding, and Adhesive Weld Bonding of Coated and Uncoated DP 600 Steel

    Institute of Scientific and Technical Information of China (English)

    Fatih Hayat

    2011-01-01

    Zinc coated dual phase 600 steel (DP 600 grade) was investigated, utilisation of which has gradually increased with each passing day in the automotive industry. The adhesive bonding (AB), resistance spot welding (RSW), and adhesive weld bonding (AWB) ioints of the zinc coated DP 600 steel were investigated. Additionally, the zinc coating was removed using HCL acid in order to investigate the effect of the coating. The microstructure, tensile shear strengths, and fracture properties of adhesive bonding (AB), resistance spot welding (RSW), and adhesive weld bonding (AWB) joints of the coated and uncoated DP 600 steel were compared. In addition, a mechani cal-electrical-thermal coupled model in a finite element analysis environment was utilised. The thermal profile phe nomenon was calculated by simulating this process. The results of the tensile shear test indicated that the tensile load bearing capacity (TLBC) values of the coated specimens among the three welding methods were higher than those of the uncoated specimens. Additionally, the tensile strength of the AWB joints of the coated and uncoated specimens was higher than that of the AB and RSW joints. It was determined that the fracture behaviours and the deformation caused were different for the three welding methods.

  13. Fracture mechanics characterisation of the WWER-440 reactor pressure vessel beltline welding seam of Greifswald unit 8

    Energy Technology Data Exchange (ETDEWEB)

    Viehrig, Hans-Werner; Schuhknecht, Jan [Forschungszentrum Dresden-Rossendorf (Germany)

    2008-07-01

    WWER-440 second generation (V-213) reactor pressure vessels (RPV) were produced by IZHORA in Russia and by SKODA in the former Czechoslovakia. The surveillance Charpy-V and fracture mechanics SE(B) specimens of both producers have different orientations. The main difference is the crack extension direction which is through the RPV thickness and circumferential for ISHORA and SKODA RPV, respectively. In particular for the investigation of weld metal from multilayer submerged welding seams the crack extension direction is of importance. Depending on the crack extension direction in the specimen there are different welding beads or a uniform structure along the crack front. The specimen orientation becomes more important when the fracture toughness of the weld metal is directly determined on surveillance specimens according to the Master Curve (MC) approach as standardised in the ASTM Standard Test Method E1921. This approach was applied on weld metal of the RPV beltline welding seam of Greifswald Unit 8 RPV. Charpy size SE(B) specimens from 13 locations equally spaced over the thickness of the welding seam were tested. The specimens are in TL and TS orientation. The fracture toughness values measured on the SE(B) specimens with both orientations follow the course of the MC. Nearly all values lie within the fracture toughness curves for 5% and 95% fracture probability. There is a strong variation of the reference temperature T{sub 0} though the thickness of the welding seam, which can be explained with structural differences. The scatter is more pronounced for the TS SE(B) specimens. It can be shown that specimens with TS and TL orientation in the welding seam have a differentiating and integrating behaviour, respectively. The statistical assumptions behind the MC approach are valid for both specimen orientations even if the structure is not uniform along the crack front. By comparison crack extension, JR, curves measured on SE(B) specimens with TL and TS orientation

  14. Effect of Welding Parameters on Microstructure and Mechanical Properties of Cast Fe-40Al Alloy

    Directory of Open Access Journals (Sweden)

    Osman Torun

    2016-09-01

    Full Text Available Friction welding of cast Fe-40Al alloy was carried out at 1000 rmp for various friction times, friction pressures, and forging pressures. The microstructures of the interface of welded samples were analyzed by optical and scanning electron microscopy (SEM. Micrographs demonstrated that excellent welding formed continuously along the interface, except for samples welded for 3 s. Chemical compositions of the interface of the friction welded samples and of the fractured surface of all the specimens were determined using energy dispersive spectroscopy (EDS. After the welding process, shear tests were applied to the welded samples to determine the shear strength of joints. Test results indicated that the maximum shear strength was 469.5 MPa.

  15. Application of artificial neural network to predict Vickers microhardness of AA6061 friction stir welded sheets

    Institute of Scientific and Technical Information of China (English)

    Vahid Moosabeiki Dehabadi; Saeede Ghorbanpour; Ghasem Azimi

    2016-01-01

    The application of friction stir welding (FSW) is growing owing to the omission of difficulties in traditional welding processes. In the current investigation, artificial neural network (ANN) technique was employed to predict the microhardness of AA6061 friction stir welded plates. Specimens were welded employing triangular and tapered cylindrical pins. The effects of thread and conical shoulder of each pin profile on the microhardness of welded zone were studied using tow ANNs through the different distances from weld centerline. It is observed that using conical shoulder tools enhances the quality of welded area. Besides, in both pin profiles threaded pins and conical shoulders increase yield strength and ultimate tensile strength. Mean absolute percentage error (MAPE) for train and test data sets did not exceed 5.4% and 7.48%, respectively. Considering the accurate results and acceptable errors in the models’ responses, the ANN method can be used to economize material and time.

  16. Effect of welding parameters of Gas Metal Arc welding on weld bead geometry: A Review

    Directory of Open Access Journals (Sweden)

    Pushp Kumar Baghel

    2012-07-01

    Full Text Available Weld quality comprises bead geometry and its microstructure, which influence the mechanical properties of the weld. This brief review illustrates the effect of pulse parameters on weld quality. The responsefactors, namely bead penetration, weld width, reinforcement height, weld penetration shape factor and weld reinforcement form factor as affected by arc voltage, wire feed rate, welding speed, gas flow rate and nozzle-toplate distance has also been analysed

  17. Optically controlled welding system

    Science.gov (United States)

    Gordon, Stephen S. (Inventor)

    1989-01-01

    An optically controlled welding system (10) wherein a welding torch (12) having through-the-torch viewing capabilities is provided with an optical beam splitter (56) to create a transmitted view and a reflective view of a welding operation. These views are converted to digital signals which are then processed and utilized by a computerized robotic welder (15) to make the welding torch responsive thereto. Other features includes an actively cooled electrode holder (26) which minimizes a blocked portion of the view by virtue of being constructed of a single spoke or arm (28) and a weld pool contour detector (14) comprising a laser beam directed onto the weld pool with the position of specular radiation reflected therefrom being characteristic of a penetrated or unpenetrated condition of the weld pool.

  18. Modification of creep and low cycle fatigue behaviour induced by welding

    Directory of Open Access Journals (Sweden)

    A. Carofalo

    2014-10-01

    Full Text Available In this work, the mechanical properties of Waspaloy superalloy have been evaluated in case of welded repaired material and compared to base material. Test program considered flat specimens on base and TIG welded material subjected to static, low-cycle fatigue and creep test at different temperatures. Results of uniaxial tensile tests showed that the presence of welded material in the gage length specimen does not have a relevant influence on yield strength and UTS. However, elongation at failure of TIG material was reduced with respect to the base material. Moreover, low-cycle fatigue properties have been determined carrying out tests at different temperature (room temperature RT and 538°C in both base and TIG welded material. Welded material showed an increase of the data scatter and lower fatigue strength, which was anyway not excessive in comparison with base material. During test, all the hysteresis cycles were recorded in order to evaluate the trend of elastic modulus and hysteresis area against the number of cycles. A clear correlation between hysteresis and fatigue life was found. Finally, creep test carried out on a limited number of specimens allowed establishing some changes about the creep rate and time to failure of base and welded material. TIG welded specimen showed a lower time to reach a fixed strain or failure when a low stress level is applied. In all cases, creep behaviour of welded material is characterized by the absence of the tertiary creep.

  19. Weld overlay cladding with iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, G.M. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    The author has established a range of compositions for these alloys within which hot cracking resistance is very good, and within which cold cracking can be avoided in many instances by careful control of welding conditions, particularly preheat and postweld heat treatment. For example, crack-free butt welds have been produced for the first time in 12-mm thick wrought Fe{sub 3}Al plate. Cold cracking, however, still remains an issue in many cases. The author has developed a commercial source for composite weld filler metals spanning a wide range of achievable aluminum levels, and are pursuing the application of these filler metals in a variety of industrial environments. Welding techniques have been developed for both the gas tungsten arc and gas metal arc processes, and preliminary work has been done to utilize the wire arc process for coating of boiler tubes. Clad specimens have been prepared for environmental testing in-house, and a number of components have been modified and placed in service in operating kraft recovery boilers. In collaboration with a commercial producer of spiral weld overlay tubing, the author is attempting to utilize the new filler metals for this novel application.

  20. Weld defect formation in FSWed coppers

    Science.gov (United States)

    Gheisari, Yousof; Pashazadeh, Hamed; Teimournezhad, Jamal; Masoumi, Abolfazl

    2014-06-01

    This work was undertaken to explore the formation of weld defects in FSWed copper metals via both numerical and experimental approaches. The 4 mm-thick copper sheets were friction stir welded at a tool rotational speed of 710 rpm and tool translational speed of 40 mm/min. Microstructural evaluations were performed on the welded specimens. Also a 3D arbitrary Lagrangian Eulerian numerical model was developed to obtain temperature and material velocity profiles. To this aim, DEFORM-3D was implemented for developing the numerical simulation. Numerical results for temperature values showed good agreement with the recorded experimental data. They also suggest that on the advancing side (AS) of the trailing side, the pin velocity has the minimum amount (zero), and this is the main reason for the formation of tunneling cavity. Experimental results show that a force is created between the reminder of material at the joint and the rim of AS. This force causes a prong of surface material from the AS rim to penetrate into lower parts of weld. It seems that the inadequate pressure (low values of the plunge depth), inadequate surface materials, and the trapped air are the main causes for the formation of the weld defects.

  1. Closeout of JOYO-1 Specimen Fabrication Efforts

    Energy Technology Data Exchange (ETDEWEB)

    ME Petrichek; JL Bump; RF Luther

    2005-10-31

    Fabrication was well under way for the JOYO biaxial creep and tensile specimens when the NR Space program was canceled. Tubes of FS-85, ASTAR-811C, and T-111 for biaxial creep specimens had been drawn at True Tube (Paso Robles, CA), while tubes of Mo-47.5 Re were being drawn at Rhenium Alloys (Cleveland, OH). The Mo-47.5 Re tubes are now approximately 95% complete. Their fabrication and the quantities produced will be documented at a later date. End cap material for FS-85, ASTAR-811C, and T-111 had been swaged at Pittsburgh Materials Technology, Inc. (PMTI) (Large, PA) and machined at Vangura (Clairton, PA). Cutting of tubes, pickling, annealing, and laser engraving were in process at PMTI. Several biaxial creep specimen sets of FS-85, ASTAR-811C, and T-111 had already been sent to Pacific Northwest National Laboratory (PNNL) for weld development. In addition, tensile specimens of FS-85, ASTAR-811C, T-111, and Mo-47.5 Re had been machined at Kin-Tech (North Huntington, PA). Actual machining of the other specimen types had not been initiated. Flowcharts 1-3 detail the major processing steps each piece of material has experienced. A more detailed description of processing will be provided in a separate document [B-MT(SRME)-51]. Table 1 lists the in-process materials and finished specimens. Also included are current metallurgical condition of these materials and specimens. The available chemical analyses for these alloys at various points in the process are provided in Table 2.

  2. The study on the properties of AISI 4140 and AISI 1040 steel rods welded by friction welding

    Directory of Open Access Journals (Sweden)

    Thanee Toomprasen

    2014-06-01

    Full Text Available This paper is aimed to investigate the properties of joint between AISI 4140 and AISI 1040 welded by friction welding. The specimens were prepared in round shape of 13 mm diameter and 100 mm long. They were welded by friction welding method under the following conditions; friction pressure of 183 MPa, friction time of 12 sec, upset pressure of 428 MPa, upset time of 7 sec. and rotational speed of 1400 rpm. The strength and hardness were tested on the welded area. The result showed finer grains. in the welded area. This is the result of friction pressure and upset pressure in the welding process. In addition, the observation result indicated some changes of Ferrite and Pearlite in welded zone. This phase change resulted in the increment of hardness in AISI 4140 at the contact area and adjacent. In part of AISI 1040, the portion of Pearlite and Ferrite are not significantly changed, therefore the value of hardness is almost constant.

  3. Radiation and annealing response of WWER 440 beltline welding seams

    Science.gov (United States)

    Viehrig, Hans-Werner; Houska, Mario; Altstadt, Eberhard

    2015-01-01

    The focus of this paper is on the irradiation response and the effect of thermal annealing in weld materials extracted from decommissioned WWER 440 reactor pressure vessels of the nuclear power plant Greifswald. The characterisation is based on the measurement of the hardness, the yield stress, the Master Curve reference temperature, T0, and the Charpy-V transition temperature through the thickness of multi-layer beltline welding seams in the irradiated and the thermally annealed condition. Additionally, the weld bead structure was characterised by light microscopic studies. We observed a large variation in the through thickness T0 values in the irradiated as well as in thermally annealed condition. The T0 values measured with the T-S-oriented Charpy size SE(B) specimens cut from different thickness locations of the multilayer welding seams strongly depend on the intrinsic weld bead structure along the crack tip. The Master Curve, T0, and Charpy-V, TT47J, based ductile-to-brittle transition temperature progressions through the thickness of the multi-layer welding seam do not correspond to the forecast according to the Russian code. In general, the fracture toughness values at cleavage failure, KJc, measured on SE(B) specimens from the irradiated and large-scale thermally annealed beltline welding seams follow the Master Curve description, but more than the expected number lie outside the curves for 2% and 98% fracture probability. In this case the test standard ASTM E1921 indicates the investigated multi-layer weld metal as not uniform. The multi modal Master Curve based approach describes the temperature dependence of the specimen size adjusted KJc-1T values well. Thermal annealing at 475 °C for 152 h results in the expected decrease of the hardness and tensile strength and the shift of Master Curve and Charpy-V based ductile-to-brittle transition temperatures to lower values.

  4. Welding arc plasma physics

    Science.gov (United States)

    Cain, Bruce L.

    1990-01-01

    The problems of weld quality control and weld process dependability continue to be relevant issues in modern metal welding technology. These become especially important for NASA missions which may require the assembly or repair of larger orbiting platforms using automatic welding techniques. To extend present welding technologies for such applications, NASA/MSFC's Materials and Processes Lab is developing physical models of the arc welding process with the goal of providing both a basis for improved design of weld control systems, and a better understanding of how arc welding variables influence final weld properties. The physics of the plasma arc discharge is reasonably well established in terms of transport processes occurring in the arc column itself, although recourse to sophisticated numerical treatments is normally required to obtain quantitative results. Unfortunately the rigor of these numerical computations often obscures the physics of the underlying model due to its inherent complexity. In contrast, this work has focused on a relatively simple physical model of the arc discharge to describe the gross features observed in welding arcs. Emphasis was placed of deriving analytic expressions for the voltage along the arc axis as a function of known or measurable arc parameters. The model retains the essential physics for a straight polarity, diffusion dominated free burning arc in argon, with major simplifications of collisionless sheaths and simple energy balances at the electrodes.

  5. VPPA weld model evaluation

    Science.gov (United States)

    McCutcheon, Kimble D.; Gordon, Stephen S.; Thompson, Paul A.

    1992-07-01

    NASA uses the Variable Polarity Plasma Arc Welding (VPPAW) process extensively for fabrication of Space Shuttle External Tanks. This welding process has been in use at NASA since the late 1970's but the physics of the process have never been satisfactorily modeled and understood. In an attempt to advance the level of understanding of VPPAW, Dr. Arthur C. Nunes, Jr., (NASA) has developed a mathematical model of the process. The work described in this report evaluated and used two versions (level-0 and level-1) of Dr. Nunes' model, and a model derived by the University of Alabama at Huntsville (UAH) from Dr. Nunes' level-1 model. Two series of VPPAW experiments were done, using over 400 different combinations of welding parameters. Observations were made of VPPAW process behavior as a function of specific welding parameter changes. Data from these weld experiments was used to evaluate and suggest improvements to Dr. Nunes' model. Experimental data and correlations with the model were used to develop a multi-variable control algorithm for use with a future VPPAW controller. This algorithm is designed to control weld widths (both on the crown and root of the weld) based upon the weld parameters, base metal properties, and real-time observation of the crown width. The algorithm exhibited accuracy comparable to that of the weld width measurements for both aluminum and mild steel welds.

  6. 37 CFR 2.59 - Filing substitute specimen(s).

    Science.gov (United States)

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Filing substitute specimen(s..., DEPARTMENT OF COMMERCE RULES OF PRACTICE IN TRADEMARK CASES Drawing § 2.59 Filing substitute specimen(s). (a... specimen(s), the applicant must: (1) For an amendment to allege use under § 2.76, verify by affidavit...

  7. HIP experiments on the first wall and cooling plate specimens for the EU HCPB blanket

    Energy Technology Data Exchange (ETDEWEB)

    Norajitra, P. E-mail: prachai.norajitra@imf.fzk.de; Reimann, G.; Ruprecht, R.; Schaefer, L

    2002-12-01

    First wall and cooling plates are considered the most important structural parts of the EU HCPB blanket concept which is based on the use of ferritic-martensitic steel as structural material, Li{sub 4}SiO{sub 4} pebbles as breeder material, beryllium pebbles as neutron multiplier, and 8 MPa helium as coolant. Both the first wall and cooling plates contain complex arrays of internal He coolant channels. The favourite manufacturing technology is diffusion welding of two halves of plates applying the hot isostatic pressure (HIP) welding method that allows uniform distribution of the pressure acting on the outer surfaces of the welding objects. The HIP experiment was started with small MANET specimens with internal coolant channels. The objective of this work is to investigate the appropriate HIP technique, boundary conditions, and parameters in order to achieve good mechanical properties of the welding joints as well as to achieve a transition to test specimens of larger dimensions.

  8. Neutron diffraction analysis of residual strain/stress distribution in the vicinity of high strength welds

    Directory of Open Access Journals (Sweden)

    Hamák I.

    2010-06-01

    Full Text Available Residual stresses resulting from non homogeneous heat distribution during welding process belong to most significant factor influencing behavior of welded structures. These stresses are responsible for defect occurrence during welding and they are also responsible for crack initiation and propagation at the either static or dynamic load. The significant effect of weld metal chemical composition as well as the effect of fatigue load and local plastic deformation on residual stress distribution and fatigue life have been recognized for high strength steels welds. The changes in residual stress distribution have then positive effect on cold cracking behavior and also on fatigue properties of the welds [1-3]. Several experimental methods, both destructive and non-destructive, such as hole drilling method, X-ray diffraction, neutron diffraction and others, have been used to examine residual stress distribution in all three significant orientations in the vicinity of the welds. The present contribution summarizes the results of neutron diffraction measurements of residual stress distribution in the vicinity of single-pass high-strength-steel welds having different chemical composition as well as the influence of fatigue load and local plastic deformation. It has been observed that the chemical composition of the weld metal has a significant influence on the stress distribution around the weld. Similarly, by aplying both cyclic load or pre-stress load on the specimens, stress relaxation was observed even in the region of approximately 40 mm far from the weld toe.

  9. Fatigue Properties of Welded Butt Joint and Base Metal of MB8 Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    Ying-xia YU

    2016-09-01

    Full Text Available The fatigue properties of welded butt joint and base metal of MB8 magnesium alloy were investigated. The comparative fatigue tests were carried out using EHF-EM200K2-070-1A fatigue testing machine for both welded butt joint and base metal specimens with the same size and shape. The fatigue fractures were observed and analyzed by a scanning electron microscope of 6360 LA type. The experimental results show that the fatigue performance of the welded butt joint of MB8 magnesium alloy is sharply decreased. The conditional fatigue limit (1×107 of base metal and welded butt joint is about 69.41 and 32.76 MPa, respectively. The conditional fatigue limit (1×107 of the welded butt joint is 47.2 % of that of base metal. The main reasons are that the welding can lead to stress concentration in the weld toe area, tensile welding residual stress in the welded joint, as well as grain coarsening in the welding seam. The cleavage steps or quasi-cleavage patterns present on the fatigue fracture surface, indicating the fracture type of the welded butt joint belongs to a brittle fracture.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.9132

  10. Experimental Evaluation and Characterization of Electron Beam Welding of 2219 AL-Alloy

    Directory of Open Access Journals (Sweden)

    Mohamed Sobih

    2016-01-01

    Full Text Available Aiming to reduce the weight of components, thus allowing a profit in terms of energy saving, automotive industry as well as aircraft industry extensively uses aluminum alloys. The most widely used joining technology in aircraft industry is riveting, while welding seems to be used in the car industry in the case of aluminum alloys. However, welding technology is characterized by many defects, such as gas porosity; oxide inclusions; solidification cracking (hot tearing; and reduced strength in both the weld and the heat affected zones which could limit its development. Many techniques are used for aluminum alloys welding, among them is electron beam welding (EBW, which has unique advantages over other traditional fusion welding methods due to high-energy density, deep penetration, large depth-to-width ratio, and small heat affected zone. The welding parameters that yield to optimal weld joint have been previously obtained. These optimal parameters were validated by welding a specimen using these parameters. To evaluate this optimal weld joint, complete, microstructural observations and characterization have been carried out using scanning electron microscopy, optical microscopy, and energy dispersive X-ray analysis. This evaluation leads to description and quantification of the solidification process within this weld joint.

  11. Feasibility study of flexible phased array ultrasonic technology using irregular surface specimen

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Pyo; Moon, Yong Sik; Jung, Nam Du [NDE Performance Demonstration Team, Korea Hydro and Nuclear Power, Central Research Institute, Daejeon (Korea, Republic of)

    2015-02-15

    Nuclear power plant contain many dissimilar metal welds that connect carbon steel components with stainless steel pipes using alloy 600 welding materials. Primary water stress corrosion cracks at dissimilar metal welds have been continuously reported around the world. In periodic integrity evaluations, dissimilar metal welds are examined using a generic ultrasonic testing procedure, KPD-UT-10. In this procedure, the gap between the probe and examination surface is limited to 1/32 inch (0.8 mm). It is not easy to test some dissimilar metal welds in Korean plants applying ordinary technology because of their tapered shapes and irregular surface conditions. This paper introduces a method for applying a flexible phased array technology to improve the reliability of ultrasonic testing results for various shapes and surface conditions. The artificial flaws in specimens with irregular surfaces were completely detected using the flexible phased array ultrasonic technology. Therefore, it can be said that the technology is applicable to field examination.

  12. Dual wire welding torch and method

    Science.gov (United States)

    Diez, Fernando Martinez; Stump, Kevin S.; Ludewig, Howard W.; Kilty, Alan L.; Robinson, Matthew M.; Egland, Keith M.

    2009-04-28

    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.

  13. Influence of irradiation conditions on the deformation of pure titanium frames in laser welding.

    Science.gov (United States)

    Shimakura, Michio; Yamada, Satoshi; Takeuchi, Misao; Miura, Koki; Ikeyama, Joji

    2009-03-01

    Due to its ease of use in connecting metal frames, laser welding is now applied in dentistry. However, to achieve precise laser welding, several problems remain to be resolved. One such problem is the influence of irradiation conditions on the deformation of titanium frameworks during laser welding, which this study sought to investigate. Board-shaped pure titanium specimens were prepared with two different joint types. Two specimens were abutted against each other to form a welding block with gypsum. For welding, three different laser waveforms were used. Deformation of the specimen caused by laser welding was measured as a rise from the gypsum surface at the opposite, free end of the specimen. It was observed that specimens with a beveled edge registered a smaller deformation than specimens with a square edge. In addition, a double laser pulse waveform--whereby a supplementary laser pulse was delivered immediately after the main pulse--resulted in a smaller deformation than with a single laser pulse waveform.

  14. Effect of Welding Parameters and Aging Process on the Mechanical Properties of Friction Stir-Welded 6063-T4 Al Alloy

    Science.gov (United States)

    Toktaş, Alaaddin; Toktaş, Gülcan

    2012-06-01

    6063-T4 Al alloy was friction stir welded at various tool rotations (800, 1120, and 1600 rpm) and welding speeds (200 and 315 mm/min) using a specially manufactured tool with a height-adjustable and right-hand-threaded pin. The postweld aging process (at 185 °C for 7 h) was applied to a group of the welded plates. In this study, the effects of the welding parameters and the postweld aging treatment on the microstructural and mechanical properties of 6063-T4 Al alloy were studied. The maximum weld temperatures during the welding process were recorded, and the fracture surfaces of tensile specimens were examined using a scanning electron microscope. The homogeneous hardness profiles were obtained for all the weldings with no trace of softening regions. It was observed that the ultimate tensile strengths (UTS) increased slightly (on average by approx. 8%) and the percent elongations decreased (on average by approx. 33%) by the postweld aging treatment. The maximum bending forces ( F max) of all the welds were less than that of the base metal. It was observed that the F max values increased after the postweld aging process at the welding speed of 315 mm/min and decreased at the welding speed of 200 mm/min.

  15. Effect of Stress Relief Annealing on Microstructure & Mechanical Properties of Welded Joints Between Low Alloy Carbon Steel and Stainless Steel

    Science.gov (United States)

    Nivas, R.; Das, G.; Das, S. K.; Mahato, B.; Kumar, S.; Sivaprasad, K.; Singh, P. K.; Ghosh, M.

    2017-01-01

    Two types of welded joints were prepared using low alloy carbon steel and austenitic stainless steel as base materials. In one variety, buttering material and weld metal were Inconel 82. In another type, buttering material and weld metal were Inconel 182. In case of Inconel 82, method of welding was GTAW. For Inconel 182, welding was done by SMAW technique. For one set of each joints after buttering, stress relief annealing was done at 923 K (650 °C) for 90 minutes before further joining with weld metal. Microstructural investigation and sub-size in situ tensile testing in scanning electron microscope were carried out for buttered-welded and buttered-stress relieved-welded specimens. Adjacent to fusion boundary, heat-affected zone of low alloy steel consisted of ferrite-pearlite phase combination. Immediately after fusion boundary in low alloy steel side, there was increase in matrix grain size. Same trend was observed in the region of austenitic stainless steel that was close to fusion boundary between weld metal-stainless steel. Close to interface between low alloy steel-buttering material, the region contained martensite, Type-I boundary and Type-II boundary. Peak hardness was obtained close to fusion boundary between low alloy steel and buttering material. In this respect, a minimum hardness was observed within buttering material. The peak hardness was shifted toward buttering material after stress relief annealing. During tensile testing no deformation occurred within low alloy steel and failure was completely through buttering material. Crack initiated near fusion boundary between low alloy steel-buttering material for welded specimens and the same shifted away from fusion boundary for stress relieved annealed specimens. This observation was at par with the characteristics of microhardness profile. In as welded condition, joints fabricated with Inconel 82 exhibited superior bond strength than the weld produced with Inconel 182. Stress relief annealing

  16. Comparison of joint designs for laser welding of cast metal plates and wrought wires.

    Science.gov (United States)

    Takayama, Yasuko; Nomoto, Rie; Nakajima, Hiroyuki; Ohkubo, Chikahiro

    2013-01-01

    The purpose of the present study was to compare joint designs for the laser welding of cast metal plates and wrought wire, and to evaluate the welded area internally using X-ray micro-focus computerized tomography (micro-CT). Cast metal plates (Ti, Co-Cr) and wrought wires (Ti, Co-Cr) were welded using similar metals. The specimens were welded using four joint designs in which the wrought wires and the parent metals were welded directly (two designs) or the wrought wires were welded to the groove of the parent metal from one or both sides (n = 5). The porosity and gap in the welded area were evaluated by micro-CT, and the maximum tensile load of the welded specimens was measured with a universal testing machine. An element analysis was conducted using an electron probe X-ray microanalyzer. The statistical analysis of the results was performed using Bonferroni's multiple comparisons (α = 0.05). The results included that all the specimens fractured at the wrought wire when subjected to tensile testing, although there were specimens that exhibited gaps due to the joint design. The wrought wires were affected by laser irradiation and observed to melt together and onto the filler metal. Both Mo and Sn elements found in the wrought wire were detected in the filler metal of the Ti specimens, and Ni was detected in the filler metal of the Co-Cr specimens. The four joint designs simulating the designs used clinically were confirmed to have adequate joint strength provided by laser welding.

  17. Challenges to Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

    This report originates from the compulsory defense during my Ph.D. study at the Technical University of Denmark. Resistance welding is an old and well-proven technology. Yet the emergence of more and more new materials, new designs, invention off new joining techniques, and more stringent...... requirement in quality have imposed challenges to the resistance welding. More some research and development have to be done to adapt the old technology to the manufacturing industry of the 21st century. In the 1st part of the report, the challenging factors to the resistance welding are reviewed. Numerical...... simulation of resistance welding has been under development for many years. Yet it is no easy to make simulation results reliable and accurate because of the complexity of resistance welding process. In the 2nd part of the report numerical modeling of resistance welding is reviewed, some critical factors...

  18. Ultrasonic Stir Welding

    Science.gov (United States)

    Nabors, Sammy

    2015-01-01

    NASA Marshall Space Flight Center (MSFC) developed Ultrasonic Stir Welding (USW) to join large pieces of very high-strength metals such as titanium and Inconel. USW, a solid-state weld process, improves current thermal stir welding processes by adding high-power ultrasonic (HPU) energy at 20 kHz frequency. The addition of ultrasonic energy significantly reduces axial, frictional, and shear forces; increases travel rates; and reduces wear on the stir rod, which results in extended stir rod life. The USW process decouples the heating, stirring, and forging elements found in the friction stir welding process allowing for independent control of each process element and, ultimately, greater process control and repeatability. Because of the independent control of USW process elements, closed-loop temperature control can be integrated into the system so that a constant weld nugget temperature can be maintained during welding.

  19. Challenges to Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

    This report originates from the compulsory defense during my Ph.D. study at the Technical University of Denmark. Resistance welding is an old and well-proven technology. Yet the emergence of more and more new materials, new designs, invention off new joining techniques, and more stringent...... requirement in quality have imposed challenges to the resistance welding. More some research and development have to be done to adapt the old technology to the manufacturing industry of the 21st century. In the 1st part of the report, the challenging factors to the resistance welding are reviewed. Numerical...... simulation of resistance welding has been under development for many years. Yet it is no easy to make simulation results reliable and accurate because of the complexity of resistance welding process. In the 2nd part of the report numerical modeling of resistance welding is reviewed, some critical factors...

  20. Explosive welding method for manufacturing ITER-grade 316L(N)/CuCrZr hollow structural member

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Rui, E-mail: mr9980@163.com [PLA University of Science and Technology, Nanjing 210007 (China); Wang, Yaohua [PLA University of Science and Technology, Nanjing 210007 (China); Wu, Jihong [Southwestern Institute of Physics, Chengdu 610041 (China); Duan, Mianjun [PLA University of Science and Technology, Nanjing 210007 (China)

    2014-12-15

    Highlights: • Develop a new explosive welding method to fabricate the cooling channel of FW. • Utilize effective energy model to accurately calculate optimal welding parameters. • Provide an efficient way for manufacturing high-ductility hollow structural member. - Abstract: In this study, a new explosive welding method provided an effective way for manufacturing ITER-grade 316L(N)/CuCrZr hollow structural member. The welding parameters (stand-off distance and explosion rate) were calculated respectively using equivalent frontal collision wave model and effective energy model. The welded samples were subject to two step heat treatment cycles (solution annealing and aging). Optical microscopy (OM) and scanning electron microscopy (SEM) were utilized to analyze the microstructure of bonding interface. The mechanical properties of the welded samples were evaluated through microhardness test and tensile test. Moreover, the sealing property of the welded specimens was measured through helium leak test. Microstructural analysis showed that the welded sample using effective energy model had an ideal wavy interface. The results of microhardness test revealed an increase in hardness for both sides near to the bonding interface. And the hardening phenomenon of interface region disappeared after the solution annealing. SEM observation indicated that the samples with the post heat treatments exhibited a ductile fracture with dimple features after tensile test. After the specimens undergo aging strengthening, there was an obvious increase in the strength for all specimens. The helium leak test results have proven that the welded specimens are soundness.

  1. Effect of Gas Tungsten Arc Welding Parameters on Hydrogen-Assisted Cracking of Type 321 Stainless Steel

    Science.gov (United States)

    Rozenak, Paul; Unigovski, Yaakov; Shneck, Roni

    2016-05-01

    The susceptibility of AISI type 321 stainless steel welded by the gas tungsten arc welding (GTAW) process to hydrogen-assisted cracking (HAC) was studied in a tensile test combined with in situ cathodic charging. Specimen charging causes a decrease in ductility of both the as-received and welded specimens. The mechanical properties of welds depend on welding parameters. For example, the ultimate tensile strength and ductility increase with growing shielding gas (argon) rate. More severe decrease in the ductility was obtained after post-weld heat treatment (PWHT). In welded steels, in addition to discontinuous grain boundary carbides (M23C6) and dense distribution of metal carbides MC ((Ti, Nb)C) precipitated in the matrix, the appearance of delta-ferrite phase was observed. The fracture of sensitized specimens was predominantly intergranular, whereas the as-welded specimens exhibited mainly transgranular regions. High-dislocation density regions and stacking faults were found in delta-ferrite formed after welding. Besides, thin stacking fault plates and epsilon-martensite were found in the austenitic matrix after the cathodic charging.

  2. Influence of Spot Welding on Welding Fatigue Properties of CR340 Steel Joints

    Institute of Scientific and Technical Information of China (English)

    Rui-bin GOU; Wen-jiao DAN; Wei-gang ZHANG

    2016-01-01

    Total 72 lapped specimens including six different kinds of CR340 steel structures were prepared to study the influence of the spot welding technology on their fatigue characteristics.Fatigue test and group method were em-ployed and performed on each sample to obtain the fatigue experimental data of each structure under four stress lev-els.The results show that the spot welding technology had a notable impact on the fatigue performance of both the shear and tensile joints.It can significantly improve the fatigue strength of the structure,the consistency and repeat-ability of experimental data,as well as the stability and reliability of the structure under dynamic load environment. The shear spot welding structure demonstrates the best fatigue performance which is very important for wide appli-cation in engineering of this method.

  3. Explosive Welding of Pipes

    Science.gov (United States)

    Drennov, Oleg; Drennov, Andrey; Burtseva, Olga

    2013-06-01

    For connection by welding it is suggested to use the explosive welding method. This method is rather new. Nevertheless, it has become commonly used among the technological developments. This method can be advantageous (saving material and physical resources) comparing to its statical analogs (electron-beam welding, argon-arc welding, plasma welding, gas welding, etc.), in particular, in hard-to-reach areas due to their geographic and climatic conditions. Explosive welding of cylindrical surfaces is performed by launching of welded layer along longitudinal axis of construction. During this procedure, it is required to provide reliable resistance against radial convergent strains. The traditional method is application of fillers of pipe cavity, which are dense cylindrical objects having special designs. However, when connecting pipes consecutively in pipelines by explosive welding, removal of the fillers becomes difficult and sometimes impossible. The suggestion is to use water as filler. The principle of non-compressibility of liquid under quasi-dynamic loading is used. In one-dimensional gasdynamic and elastic-plastic calculations we determined non-deformed mass of water (perturbations, which are moving in the axial direction with sound velocity, should not reach the layer end boundaries for 5-7 circulations of shock waves in the radial direction). Linear dimension of the water layer from the zone of pipe coupling along axis in each direction is >= 2R, where R is the internal radius of pipe.

  4. Explosive welding of pipes

    Energy Technology Data Exchange (ETDEWEB)

    Drennov, O.; Burtseva, O.; Kitin, A. [Russian Federal Nuclear Center, Sarov (Russian Federation)

    2006-08-15

    Arrangement of pipelines for the transportation of oil and gas is a complicated problem. In this paper it is suggested to use the explosive welding method to weld pipes together. This method is rather new. This method can be advantageous (saving material and physical resources) comparing to its static analogs (electron-beam welding, argon-arc welding, plasma welding, gas welding, etc.), in particular, in hard-to-reach areas due to their geographic and climatic conditions. We suggest to perform explosive welding according to the following scheme: the ends of the 2 pipes are connected, the external surfaces are kept at a similar level. A cylindrical steel layer of diameter larger than the pipe diameter is set around the pipe joint and an explosive charge is placed on its external surface. The basic problem is the elimination of strains and reduction of pipe diameter in the area of the dynamic effect. The suggestion is to use water as filler: the volume of pipes in the area adjacent to the zone of explosive welding is totally filled with water. The principle of non-compressibility of liquid under quasi-dynamic loading is used. In one-dimensional gas dynamic and elastic-plastic calculations we determined non-deformed mass of water. Model experiments with pipes having radii R = 57 mm confirmed results of the calculations and the possibility in principle to weld pipes by explosion with use of water as filler.

  5. Influence of induction hardening parameters on the GS30Mn5 weld properties

    Directory of Open Access Journals (Sweden)

    V. Marušić

    2016-10-01

    Full Text Available This study examines parameters of post-weld heat treatment on the test specimens made of cast steel GS30Mn5. The welding is performed with shielded metal arc welding (SMAW process. The aim is to obtain the surface without illicit cracks, with hardness ranging from 320 up to 400 HB. After induction heating, the specimens are cooled alternately with air and water. Decreased speed of quenching results in avoiding the occurrence of illicit splashes, while the hardness is maintained within the prescribed limits.

  6. Low Cycle Fatigue behavior of SMAW welded Alloy28 superaustenitic stainless steel at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kchaou, Y., E-mail: yacinekchaou@yahoo.fr [Institut Pprime, Département Physique et Mécanique des Matériaux, UPR 3346 CNRS ISAE-ENSMA Université de Poitiers, Téléport 2, 1, avenue Clément Ader, BP 40109, F – 86961 Futuroscope Chasseneuil Cedex (France); Laboratoire de Génie des Matériaux et Environnement (LGME), ENIS, BPW 1173, Sfax (Tunisia); Pelosin, V.; Hénaff, G. [Institut Pprime, Département Physique et Mécanique des Matériaux, UPR 3346 CNRS ISAE-ENSMA Université de Poitiers, Téléport 2, 1, avenue Clément Ader, BP 40109, F – 86961 Futuroscope Chasseneuil Cedex (France); Haddar, N.; Elleuch, K. [Laboratoire de Génie des Matériaux et Environnement (LGME), ENIS, BPW 1173, Sfax (Tunisia)

    2016-01-10

    This paper focused on the study of Low Cycle Fatigue of welded joints of superaustenitic (Alloy28) stainless steels. Chemical composition and microstructure investigation of Base Metal (BM) and Weld Metal (WM) were identified. The results showed that both of composition is fully austenitic with a dendritic microstructure in the WM. Low cycle fatigue tests at different strain levels were performed on Base Metal (BM) and Welded Joint (WJ) specimens with a strain ratio R{sub ε}=−1. The results indicated that the fatigue life of welded joints is lower than the base metal. This is mainly due to the low ductility of the Welded Metal (WM) and the presence of welding defects. Simultaneously, Scanning Electron Microscope (SEM) observations of fractured specimens show that WJ have brittle behavior compared to BM with the presence of several welding defects especially in the crack initiation site. An estimation of the crack growth rate during LCF tests of BM and WJ was performed using distance between striations. The results showed that the crack initiation stage is shorter in the case of WJ compared to BM because of the presence of welding defects in WJ specimens.

  7. Controlled Environment Specimen Transfer

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Zandbergen, Henny W.; Hansen, Thomas Willum

    2014-01-01

    Specimen transfer under controlled environment conditions, such as temperature, pressure, and gas composition, is necessary to conduct successive complementary in situ characterization of materials sensitive to ambient conditions. The in situ transfer concept is introduced by linking an environme...

  8. Application of welding simulation to block joints in shipbuilding and assessment of welding-induced residual stresses and distortions

    Directory of Open Access Journals (Sweden)

    Fricke Wolfgang

    2014-06-01

    Full Text Available During ship design, welding-induced distortions are roughly estimated as a function of the size of the component as well as the welding process and residual stresses are assumed to be locally in the range of the yield stress. Existing welding simulation methods are very complex and time-consuming and therefore not applicable to large structures like ships. Simplified methods for the estimation of welding effects were and still are subject of several research projects, but mostly concerning smaller structures. The main goal of this paper is the application of a multi-layer welding simulation to the block joint of a ship structure. When welding block joints, high constraints occur due to the ship structure which are assumed to result in accordingly high residual stresses. Constraints measured during construction were realized in a test plant for small-scale welding specimens in order to investigate their and other effects on the residual stresses. Associated welding simulations were successfully performed with fine-mesh finite element models. Further analyses showed that a courser mesh was also able to reproduce the welding-induced reaction forces and hence the residual stresses after some calibration. Based on the coarse modeling it was possible to perform the welding simulation at a block joint in order to investigate the influence of the resulting residual stresses on the behavior of the real structure, showing quite interesting stress distributions. Finally it is discussed whether smaller and idealized models of definite areas of the block joint can be used to achieve the same results offering possibilities to consider residual stresses in the design process.

  9. Investigation of Using Waste Welded Tuff Material as Mineral Filler in Asphalt Concrete

    Directory of Open Access Journals (Sweden)

    Sebnem KARAHANCER

    2016-08-01

    Full Text Available In this paper, the welded tuff waste- known as koyke in Isparta region - was used in the hot mix asphalt (HMA as mineral filler for reduction of the moisture susceptibility of HMA. Optimum binder content was assessed with Marshall Design Method. First of all, welded tuff was substituted as filler with limestone filler in proportion of 50% and 100%. After that Marshall Stability test was performed on specimens. The results showed that the 50% substitution was more effective than the 100% substitution. Therefore, welded tuff was substituted with limestone filler in proportion of 25%, 50%, 65% and 75%. Next, Indirect Tensile Strength test was practiced on the fabricated specimens and the results were assessed. According to the Indirect Tensile Strength results, welded tuff with 65% was given higher strength than the limestone filler. As a result, it has come up that welded tuff can be used as mineral filler in the hot mix asphalt.

  10. Mechanical Characteristics of 9% Ni Steel Welded Joint for Lng Storage Tank at Cryogenic

    Science.gov (United States)

    Yoon, Yong-Keun; Kim, Jae-Hoon; Shim, Kyu-Taek; Kim, Young-Kyun

    To confirm the safety performance of LNG storage tank, the change in fatigue crack growth rate and fracture toughness within X-grooved weld heat-affected zone (HAZ) of newly developed 9% Ni steel, which was SMAW welded, was investigated. These materials were produced by QT (quenching, tempering) heat treatment. The weld metal specimens were prepared by taking the same weld procedure applied in actual inner shell of LNG storage tank. All tests were performed in the temperature ranging from R.T. and -162°C. The fatigue crack growth behavior was carried out using CT specimen. Investigation has been carried out to study the influence of temperature and weld effect on fatigue crack growth behavior. Also, Fracture surfaces after tests were observe by scanning electron microscope (SEM).

  11. Mechanical properties of friction stir welded aluminum alloys 5083 and 5383

    Directory of Open Access Journals (Sweden)

    Jeom Kee Paik

    2009-09-01

    Full Text Available The use of high-strength aluminum alloys is increasing in shipbuilding industry, particularly for the design and construction of war ships, littoral surface craft and combat ships, and fast passenger ships. While various welding methods are used today to fabricate aluminum ship structures, namely gas metallic arc welding (GMAW, laser welding and friction stir welding (FSW, FSW technology has been recognized to have many advantages for the construction of aluminum structures, as it is a low-cost welding process. In the present study, mechanical properties of friction stir welded aluminum alloys are examined experimentally. Tensile testing is undertaken on dog-bone type test specimen for aluminum alloys 5083 and 5383. The test specimen includes friction stir welded material between identical alloys and also dissimilar alloys, as well as unwelded (base alloys. Mechanical properties of fusion welded aluminum alloys are also tested and compared with those of friction stir welded alloys. The insights developed from the present study are documented together with details of the test database. Part of the present study was obtained from the Ship Structure Committee project SR-1454 (Paik, 2009, jointly funded by its member agencies.

  12. Microstructure and Mechanical Properties of Laser Beam Welds of 15CDV6 Steel

    Directory of Open Access Journals (Sweden)

    M.V.L Ramesh

    2015-07-01

    Full Text Available The present study is concerned with laser beam welding of 15CDV6 steel, that is in the hardened (quenched and tempered condition before welding. Autogenously butt-welded joints are made using carbon dioxide laser with a maximum output of 3.5 kw in the continuous wave mode. Weld microstructure, microhardness measurement across the weldment, transverse tensile properties, and room temperature impact properties of the weldment have been evaluated. The fusion zone exhibits a epitaxial grain growth. The microstrutural features of heat-affected zone and fusion zone vary, due to different thermal cycles for which these were subjected during welding. The average weld metal hardness was 480 Hv. The observed hardness distribution across the welds were correlated with the microstructures. The welds exhibited lower toughness of 50 joules as compared to parent metal of 55 joules and the tensile strength values of the welded specimens are close to that obtained for sheet specimens.Defence Science Journal, Vol. 65, No. 4, July 2015, pp. 339-342, DOI: http://dx.doi.org/10.14429/dsj.65.8749

  13. Development of Fabrication Procedure and Welding Performance Test for ITER HCCR TBM

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J. S.; Lee, E. H.; Kim, S. K.; Lee, D. W.; Shin, K. I.; Jin, H. G. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, S. [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Korea has developed and plans to test a Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) in the ITER. The HCCR TBM is composed of four sub-modules and a back manipulator (BM). Each sub-module is composed of a first wall (FW), a breeding box with a seven-layer breeding zone (BZ), and side walls (SW) with a cooling path. The front surface of the sub-module is 231 mm in width and 835 mm in height. The test specimens of the ARAA were prepared to test the weldability for tungsten inert gas (TIG) welding and electron beam (EB) welding. To establish and optimize the welding procedure in an EB weld from ARRA material, the variation in the bead width and penetration depth according to the welding current and welding speed were investigated. To verify the weldability and fabrication procedure for a complex structure such as the breeding zone, a small box with a cooling channel is being fabricated using the ARAA steel under development. A fabrication procedure of a HCCR TBM submodule was designed for a first wall, breeding zone including the side wall, and assembled sub-module by welding the first wall and breeding zone box. A plate for the test specimen to evaluate the welding characteristics was fabricated based on the optimized E-beam welding results.

  14. Microstructural observations of HFIR-irratiated austenitic stainless steels including welds from JP9-16

    Energy Technology Data Exchange (ETDEWEB)

    Sawai, T.; Shiba, K.; Hishinuma, A.

    1996-04-01

    Austenitic stainless steels, including specimens taken from various electron beam (EB) welds, have been irradiated in HFIR Phase II capsules, JP9-16. Fifteen specimens irradiated at 300, 400, and 500{degrees}C up to 17 dpa are so far examined by a transmission electron microscope (TEM). In 300{degrees}C irradiation, cavities were smaller than 2nm and different specimens showed little difference in cavity microstructure. At 400{degrees}C, cavity size was larger, but still very small (<8 nm). At 500{degrees}C, cavity size reached 30 nm in weld metal specimens of JPCA, while cold worked JPCA contained a small (<5 nm) cavities. Inhomogeneous microstructural evolution was clearly observed in weld-metal specimens irradiated at 500{degrees}C.

  15. Improved diffusion welding and roll welding of titanium alloys

    Science.gov (United States)

    Holko, K. H.

    1973-01-01

    Auto-vacuum cleaning technique was applied to titanium parts prior to welding. This provides oxide-free welding surfaces. Diffusion welding can be accomplished in as little as five minutes of hot pressing. Roll welding can be accomplished with only ten percent deformation.

  16. A Review: Welding Of Dissimilar Metal Alloys by Laser Beam Welding & Friction Stir Welding Techniques

    Directory of Open Access Journals (Sweden)

    Ms. Deepika Harwani

    2014-12-01

    Full Text Available Welding of dissimilar metals has attracted attention of the researchers worldwide, owing to its many advantages and challenges. There is no denial in the fact that dissimilar welded joints offer more flexibility in the design and production of the commercial and industrial components. Many welding techniques have been analyzed to join dissimilar metal combinations. The objective of this paper is to review two such techniques – Laser welding and Friction stir welding. Laser beam welding, a high power density and low energy-input process, employs a laser beam to produce welds of dissimilar materials. Friction stir welding, a solid-state joining process, is also successfully used in dissimilar welding applications like aerospace and ship building industries. This paper summarizes the trends and advances of these two welding processes in the field of dissimilar welding. Future aspects of the study are also discussed.

  17. Laser-welded V-Cr-Ti alloys: Microstructure and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.; Smith, D.L.; Xu, Z.; Leong, K.H. [Argonne National Lab., IL (United States)

    1998-09-01

    A systematic study has been in progress at Argonne National Laboratory to examine the use of YaG or CO{sub 2} lasers to weld sheet materials of V-Cr-Ti alloys and to characterize the microstructural and mechanical properties of the laser-welded materials. In addition, several postwelding heat treatments are being applied to the welded samples to evaluate their benefits, if any, to the structure and properties of the weldments. Hardness measurements are made across the welded regions of different samples to evaluate differences in the characteristics of various weldments. Several weldments were used to fabricate specimens for four-point bend tests. Several additional weldments were made with a YaG laser; here, the emphasis was on determining the optimal weld parameters to achieve deep penetration in the welds. A preliminary assessment was then made of the weldments on the basis of microstructure, hardness profiles, and defects.

  18. Improving fatigue performance of welded joints of X65 pipeline steel by UIT

    Institute of Scientific and Technical Information of China (English)

    Liu Jinming; Chen Tong; Zhang Yufeng

    2005-01-01

    Treating weld toes properly can improve the fatigue performance. Ultrasonic impact treatment (UIT) is a more effective and convenient method to enhance the fatigue strength of welded joints and suchlike structures. Fatigue tests were conducted on the specimens made of X65 pipeline steel. The test specimens were investigated on the fatigue strength and the fatigue life at the same stress range level by comparing the ones peened by UIT with the others without the treatment: the fatigue strength of the specimens as UIT, 90% of the fatigue strength of the base mental, is increased by 38% compared with that of as welded only; the fatigue life of the ones as UIT is prolonged by 11 multiples of the ones as welded only.

  19. Fine welding with lasers.

    Science.gov (United States)

    MacLellan, D

    2008-01-01

    The need for micro joining metallic alloys for surgical instruments, implants and advanced medical devices is driving a rapid increase in the implementation of laser welding technology in research, development and volume production. This article discusses the advantages of this welding method and the types of lasers used in the process.

  20. Simulation of welding

    Institute of Scientific and Technical Information of China (English)

    Chuan-Song WU; Michael RETHMEIER; Christopher SCHWENK

    2011-01-01

    @@ Welding has become the most important materials processing technology in manufacturing, and has critical effects on the quality, reliability and life of products as well as production cost, efficiency and response speed to market.As various kinds of high performance metallic materials are widely used in engineering, there are more demands in manufacturing industry for advanced welding technology.

  1. Does pattern-welding make Anglo-Saxon swords stronger?

    DEFF Research Database (Denmark)

    Birch, Thomas

    2013-01-01

    to assess whether the technique affects mechanical properties, this experimental study compared pattern-welded and plain forged blanks in a series of material tests. Specimens were subject to tensile, Charpy and Vickers diamond hardness testing. This was to investigate the relative strength, ductility...

  2. Fracture mechanics characterisation of the WWER-440 reactor pressure vessel beltline welding seam

    Energy Technology Data Exchange (ETDEWEB)

    Viehrig, Hans-Werner [Forschungszentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany)], E-mail: H.W.Viehrig@fzd.de; Schuhknecht, Jan [Forschungszentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany)

    2009-04-15

    The master curve (MC) approach as standardised in the ASTM Standard Test Method E1921 was applied to weld metal of the reactor pressure vessel (RPV) beltline welding seam of Greifswald unit 8 RPV. Charpy size SE(B) specimens from 13 locations equally spaced over the thickness of the welding seam were tested. The orientation of the specimens within the welding seam is TL and TS according to ASTM E399. The fracture toughness values measured on the SE(B) specimens with both orientations follow the course of the master curve. Nearly all values lie within the fracture toughness curves for 2% and 98% fracture probability. There is a strong variation of the reference temperature T{sub 0} through the thickness of the welding seam, which can be explained by microstructural differences. The scatter is more pronounced for the TS SE(B) specimens. It can be shown that specimens with TL and TS orientation in the welding seam have a differentiating and integrating behaviour, respectively.

  3. Notched Tensile and Impact Fracture of Ti-15-3 Laser Welds

    Science.gov (United States)

    Tsay, Leu-Wen; Wu, Yan-Jie; Chen, Chun

    2011-12-01

    The notched tensile strength (NTS) and impact toughness of Ti-15V-3Cr-3Sn-3Al ( β-type titanium alloy Ti-15-3) laser welds aged at temperatures ranging from 590 K to 866 K (317 °C to 593 °C) were determined, and the results were compared to those of unwelded Ti-15-3 plates aged at the same temperature. At a given aging temperature, α precipitates in welded specimens were finer and exhibited higher hardness than those in unwelded specimens. Among the tested specimens, the weld aged at 644 K (371 °C) was most susceptible to notch sensitivity. In those welds aged at or above 755 K (482 °C), the coarse columnar structure was prone to interdendritic fracture during notched tensile tests, which reduced the NTS of the weld relative to that of the unwelded plate aged at an equivalent temperature. Of the tested specimens, the weld that was not subjected to the postweld aging treatment possessed the highest impact toughness among the specimens.

  4. Vacuum Gas Tungsten Arc Welding

    Science.gov (United States)

    Weeks, J. L.; Todd, D. T.; Wooten, J. R.

    1997-01-01

    A two-year program investigated vacuum gas tungsten arc welding (VGTAW) as a method to modify or improve the weldability of normally difficult-to-weld materials. After a vacuum chamber and GTAW power supply were modified, several difficult-to-weld materials were studied and key parameters developed. Finally, Incoloy 903 weld overlays were produced without microfissures.

  5. Alternating-Polarity Arc Welding

    Science.gov (United States)

    Schwinghamer, R. J.

    1987-01-01

    Brief reversing polarity of welding current greatly improves quality of welds. NASA technical memorandum recounts progress in art of variable-polarity plasma-arc (VPPA) welding, with emphasis on welding of aluminum-alloy tanks. VPPA welders offer important advantages over conventional single-polarity gas/tungsten arc welders.

  6. High Strain Rate Testing of Welded DOP-26 Iridium

    Energy Technology Data Exchange (ETDEWEB)

    Schneibel, J. H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Miller, R. G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Carmichael, C. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fox, E. E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ulrich, G. B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); George, E. P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    The iridium alloy DOP-26 is used to produce Clad Vent Set cups that protect the radioactive fuel in radioisotope thermoelectric generators (RTGs) which provide electric power for spacecraft and rovers. In a previous study, the tensile properties of DOP-26 were measured over a wide range of strain rates and temperatures and reported in ORNL/TM-2007/81. While that study established the properties of the base material, the fabrication of the heat sources requires welding, and the mechanical properties of welded DOP-26 have not been extensively characterized in the past. Therefore, this study was undertaken to determine the mechanical properties of DOP-26 specimens containing a transverse weld in the center of their gage sections. Tensile tests were performed at room temperature, 750, 900, and 1090°C and engineering strain rates of 1×10-3 and 10 s-1. Room temperature testing was performed in air, while testing at elevated temperatures was performed in a vacuum better than 1×10-4 Torr. The welded specimens had a significantly higher yield stress, by up to a factor of ~2, than the non-welded base material. The yield stress did not depend on the strain rate except at 1090°C, where it was slightly higher for the faster strain rate. The ultimate tensile stress, on the other hand, was significantly higher for the faster strain rate at temperatures of 750°C and above. At 750°C and above, the specimens deformed at 1×10-3 s-1 showed pronounced necking resulting sometimes in perfect chisel-edge fracture. The specimens deformed at 10 s-1 exhibited this fracture behavior only at the highest test temperature, 1090°C. Fracture occurred usually in the fusion zone of the weld and was, in most cases, primarily intergranular.

  7. Multispot fiber laser welding

    DEFF Research Database (Denmark)

    Schutt Hansen, Klaus

    This dissertation presents work and results achieved in the field of multi beam fiber laser welding. The project has had a practical approach, in which simulations and modelling have been kept at a minimum. Different methods to produce spot patterns with high power single mode fiber lasers have...... been possible to control the welding width in incremental steps by adding more beams in a row. The laser power was used to independently control the keyhole and consequently the depth of fusion. An example of inline repair of a laser weld in butt joint configuration was examined. Zinc powder was placed...... in the weld causing expulsion of the melt pool. Trailing beams were applied to melt additional material and ensure a melt pool. The method showed good results for increasing tolerances to impurities and reduction of scrapped parts from blowouts during laser welding....

  8. Rheomorphism of welded tuffs

    Science.gov (United States)

    Wolff, J. A.; Wright, J. V.

    1981-05-01

    Peralkaline welded tuffs from the islands of Gran Canaria, Canary Islands, and Pantelleria, Italy, show abundant evidence for post-depositional flow. It is demonstrated that rheomorphism, or secondary mass flowage, can occur in welded tuffs of ignimbrite and air-fall origin. The presence of a linear fabric is taken as the diagnostic criterion for the recognition of the process. Deposition on a slope is an essential condition for the development of rheomorphism after compaction and welding. Internal structures produced during rheomorphic flow can be studied by the methods of structural geology and show similar dispositions to comparable features in sedimentary slump sheets. It is shown that secondary flowage can occur in welded tuffs emplaced on gentle slopes, provided that the apparent viscosity of the magma is sufficiently low. Compositional factors favor the development of rheomorphism in densely welded tuffs of peralkaline type.

  9. Mechanical properties of 9Cr–1W reduced activation ferritic martensitic steel weldment prepared by electron beam welding process

    Energy Technology Data Exchange (ETDEWEB)

    Das, C.R., E-mail: chitta@igcar.gov.in [Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Albert, S.K. [Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Sam, Shiju [Institute for Plasma Research, Gandhinagar (India); Mastanaiah, P. [Defense Research and Development Laboratory, Hyderabad (India); Chaitanya, G.M.S.K.; Bhaduri, A.K.; Jayakumar, T. [Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Murthy, C.V.S. [Defense Research and Development Laboratory, Hyderabad (India); Kumar, E. Rajendra [Institute for Plasma Research, Gandhinagar (India)

    2014-11-15

    Highlights: • Width of HAZ is smaller in the 9Cr–1W RAFM weldment prepared by EB process compared to that reported for TIG weldments in literature. • Weld joint is stronger than that of the base metal. • Toughness of weld metal prepared by EB welding process is comparable to that (in PWHT condition) prepared by TIG process. • DBTT of as-welded 9Cr–1W RAFM weldment prepared by EB process is comparable to that reported for TIG weld metal in PWHT condition. - Abstract: Microstructure and mechanical properties of the weldments prepared from 9Cr–1W reduced activation ferritic martensitic (RAFM) steel using electron beam welding (EBW) process were studied. Microstructure consists of tempered lath martensite where precipitates decorating the boundaries in post weld heat treated (PWHT) condition. Lath and precipitate sizes were found to be finer in the weld metal than in base metal. Accordingly, hardness of the weld metal was found to be higher than the base metal. Tensile strength of the cross weldment specimen was 684 MPa, which was comparable with the base metal tensile strength of 670 MPa. On the other hand, DBTT of 9Cr–1W weld metal in as-welded condition is similar to that reported for TIG weld metal in PWHT condition.

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

    Science.gov (United States)

    Jandová, D.; Kasl, J.; Rek, A.

    2010-02-01

    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.

  11. Microstructure and high temperature properties of the dissimilar weld between ferritic stainless steel and carbon steel

    Science.gov (United States)

    Kim, Jeong Kil; Hong, Seung Gab; Kang, Ki Bong; Kang, Chung Yun

    2009-10-01

    Dissimilar joints between STS441, a ferritic stainless steel, and SS400, a carbon steel, were welded by GMAW (Gas Metal Arc Welding) using STS430LNb as a welding wire. The fracture behavior of the dissimilar weld was analyzed by a microstructural observation and thermo-mechanical tests. Martensite was formed at the region between SS400 and the weld metal because the Cr and Nb content in this region decreased due to the dilution of SS400 carbon steel during welding. According to results from a high temperature tensile test with a specimen aged at 900 °C, it was found that the tensile strength of the dissimilar weld at high temperature was equal to that of STS441 base metal and the formation of martensite had little influence on tensile strength of the dissimilar weld at high temperature. However, in the case of thermal fatigue resistance, the dissimilar weld had an inferior thermal fatigue life to STS441 because of the presence of martensite and the softened region around the interface between the dissimilar weld metal and SS400.

  12. Friction Stir Welding of Steel: Heat Input, Microstructure, and Mechanical Property Co-relation

    Science.gov (United States)

    Husain, Md. M.; Sarkar, R.; Pal, T. K.; Prabhu, N.; Ghosh, M.

    2015-09-01

    Friction stir welding was performed to join carbon steel plates at tool rotational rate of 800-1400 rpm. Microstructure and microhardness of welded specimens were evaluated across weld centerline. Torque base index, peak temperature, cooling rate, strain, strain rate, volumetric material flow rate, and width of extruded zone at weld nugget were calculated. Peak temperature at weld nugget was ~1300-1360 K. At this temperature, ferrite transformed to austenite during welding. Austenite was decomposed in to ferrite and bainite at cooling rate of ~4-7.5 K/s. The presence of bainite was endorsed by increment in microhardness with respect to base material. Ferrite grain size at weld nugget was finer in comparison to as-received alloy. With the increment in tool rotational rate strain, strain rate, total heat input, and peak temperature at weld nugget were increased. High temperature at weld nugget promoted increment in ferrite grain size and reduction in area fraction of bainite. Heat-affected zone also experienced phase transformation and exhibited enhancement in ferrite grain size in comparison to base alloy at all welding parameters with marginal drop in microhardness. Maximum joint strength was obtained at the tool rotational rate of 1000 rpm. Increment in tool rational rate reduced the joint efficiency owing to increment in ferrite grain size and reduction in pearlite area fraction at heat-affected zone.

  13. The influences of precrack orientations in welded joint of Ti-6Al-4V on fatigue crack growth

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xuedong, E-mail: wxue2004@yeah.net [Key Laboratory for Advanced Materials Processing Technology of Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Shi Qingyu; Wang Xin; Zhang Zenglei [Key Laboratory for Advanced Materials Processing Technology of Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)

    2010-02-15

    Ti-6Al-4V lamella microstructure obtained by {beta} annealing, which had slow fatigue crack propagation rate and high propagation resistance, was used as base metal and welded by tungsten-inert-gas welding (TIG). Three kinds of orientations were designed to study the influences of precrack orientations and locations on fatigue crack growth rate in as-weld welded joints. In comparison, the classical total-life fatigue performances of the joints were also studied. The results showed that, no matter the precrack was initiated in the center of the weld, near the fusion-line or in HAZ, the fatigue crack propagation rates in the initial stage were all slower than that of the base metal. The fatigue crack in the central region of the weld seam propagated by striation mechanism in the initial propagation stage, and the weld metal exhibited lower fatigue crack propagation rate and higher threshold stress intensity than the base metal and the other joint specimens.

  14. Tensile strength and corrosion resistance of brazed and laser-welded cobalt-chromium alloy joints.

    Science.gov (United States)

    Zupancic, Rok; Legat, Andraz; Funduk, Nenad

    2006-10-01

    The longevity of prosthodontic restorations is often limited due to the mechanical or corrosive failure occurring at the sites where segments of a metal framework are joined together. The purpose of this study was to determine which joining method offers the best properties to cobalt-chromium alloy frameworks. Brazed and 2 types of laser-welded joints were compared for their mechanical and corrosion characteristics. Sixty-eight cylindrical cobalt-chromium dental alloy specimens, 35 mm long and 2 mm in diameter, were cast. Sixteen specimens were selected for electrochemical measurements in an artificial saliva solution and divided into 4 groups (n=4). In the intact group, the specimens were left as cast. The specimens of the remaining 3 groups were sectioned at the center, perpendicular to the long-axis, and were subsequently rejoined by brazing (brazing group) or laser welding using an X- or I-shaped joint design (X laser and I laser groups, respectively). Another 16 specimens were selected for electrochemical measurements in a more acidic artificial saliva solution. These specimens were also divided into 4 groups (n=4) as described above. Electrochemical impedance spectroscopy and potentiodynamic polarization were used to assess corrosion potentials, breakdown potentials, corrosion current densities, total impedances at lowest frequency, and polarization charge-transfer resistances. The remaining 36 specimens were used for tensile testing. They were divided into 3 groups in which specimen pairs (n=6) were joined by brazing or laser welding to form 70-mm-long cylindrical rods. The tensile strength (MPa) was measured using a universal testing machine. Differences between groups were analyzed using 1-way analysis of variance (alpha=.05). The fracture surfaces and corrosion defects were examined with a scanning electron microscope. The average tensile strength of brazed joints was 792 MPa and was significantly greater (P<.05) than the tensile strength of both types of

  15. Radiation and annealing response of WWER 440 beltline welding seams

    Energy Technology Data Exchange (ETDEWEB)

    Viehrig, Hans-Werner, E-mail: h.w.viehrig@hzdr.de; Houska, Mario; Altstadt, Eberhard

    2015-01-15

    Highlights: • Investigation of the beltline welding seam from decommissioned reactor pressure vessels. • The Master Curve based reference temperature varies strongly through the thickness. • This variation is mainly caused by the intrinsic weld bead structure. • The Charpy-V based ductile-to-brittle temperature shift does not correspond to the prediction. • The mitigation of the irradiation induced embrittlement by annealing has been confirmed. - Abstract: The focus of this paper is on the irradiation response and the effect of thermal annealing in weld materials extracted from decommissioned WWER 440 reactor pressure vessels of the nuclear power plant Greifswald. The characterisation is based on the measurement of the hardness, the yield stress, the Master Curve reference temperature, T{sub 0}, and the Charpy-V transition temperature through the thickness of multi-layer beltline welding seams in the irradiated and the thermally annealed condition. Additionally, the weld bead structure was characterised by light microscopic studies. We observed a large variation in the through thickness T{sub 0} values in the irradiated as well as in thermally annealed condition. The T{sub 0} values measured with the T–S-oriented Charpy size SE(B) specimens cut from different thickness locations of the multilayer welding seams strongly depend on the intrinsic weld bead structure along the crack tip. The Master Curve, T{sub 0}, and Charpy-V, TT{sub 47J}, based ductile-to-brittle transition temperature progressions through the thickness of the multi-layer welding seam do not correspond to the forecast according to the Russian code. In general, the fracture toughness values at cleavage failure, K{sub Jc}, measured on SE(B) specimens from the irradiated and large-scale thermally annealed beltline welding seams follow the Master Curve description, but more than the expected number lie outside the curves for 2% and 98% fracture probability. In this case the test standard ASTM

  16. A Combined Experimental/Computational Analysis of the Butt-Friction-Stir-Welded AA2139-T8 Joints

    Science.gov (United States)

    Grujicic, M.; Snipes, J. S.; Ramaswami, S.; Yen, C.-F.

    2016-07-01

    Combined experimental and computational investigations are carried out of the mechanical properties of materials residing in different weld zones of friction stir-welded (FSW) joints of thick plates of AA2139-T8. The experimental portion of the work comprised (a) identification of the weld zones within the FSW joints, through the use of optical-microscopy characterization of a transverse section; (b) validation of the weld zones identified in (a) via the generation of a micro-hardness field over the same transverse section; (c) extracting and subsequently testing miniature tensile specimens from different weld zones; and (d) extracting and testing a larger-size tensile specimen spanning transversely the FSW weld. The computational portion of the work comprised (i) validation of the mechanical properties, as determined experimentally using the miniature tensile specimens, of the material residing within different zones of the FSW joint; and (ii) clarification of the benefits yielded by the knowledge of the local material properties within the FSW joint. These benefits arise from the fact that (a) joint mechanical properties are generally inferior to those of the base metal; (b) the width of the weld in thick metallic-armor is often comparable to the armor thickness, and therefore may represent a significant portion of the armor exposed-surface area; and (c) modeling of the weld-material structural response under loading requires the availability of high-fidelity/validated material constitutive models, and the development of such models requires knowledge of the local weld-material mechanical properties.

  17. Micro–macro-characterisation and modelling of mechanical properties of gas metal arc welded (GMAW) DP600 steel

    Energy Technology Data Exchange (ETDEWEB)

    Ramazani, A., E-mail: ali.ramazani@iehk.rwth-aachen.de [Department of Ferrous Metallurgy, RWTH Aachen University, D-52072 Aachen (Germany); Mukherjee, K. [Department of Ferrous Metallurgy, RWTH Aachen University, D-52072 Aachen (Germany); Abdurakhmanov, A. [Welding and Joining Institute, RWTH Aachen University, D-52072 Aachen (Germany); Prahl, U. [Department of Ferrous Metallurgy, RWTH Aachen University, D-52072 Aachen (Germany); Schleser, M.; Reisgen, U. [Welding and Joining Institute, RWTH Aachen University, D-52072 Aachen (Germany); Bleck, W. [Department of Ferrous Metallurgy, RWTH Aachen University, D-52072 Aachen (Germany)

    2014-01-01

    Dual-phase (DP) steels show combined high strength and adequate formability. However, during welding, their microstructural feature of dispersion of hard martensite islands in the soft ferrite matrix is lost and the properties deteriorate. The current research aims to study the mechanical properties of the welded joint, taking into account the effect of features of all regions, such as microstructure, chemical composition and the area fraction, on the macroscopic mechanical properties of the welded joint. Hot rolled DP 600 steel was gas metal arc welded (GMAW) and tensile specimens were made with a welded joint. In the heat-affected zone (HAZ), the microstructure varied from bainite to coarse grained ferrite and tempered martensite. Chemical composition of every quantified region in the welded specimen was also identified using electron probe microanalysis (EPMA). Macromechanical FE modelling was employed to simulate the mechanical properties of the welded tensile specimen. 2D representative volume elements (RVE) for different parts of the welded region were constructed from real microstructure. 2D simulated flow curves were corrected to 3Ds using a developed correlation factor. Finally, the tensile test of welded material with inhomogeneous morphology was simulated and good agreement between experimental and predicted flow curve was achieved.

  18. Behavior of welds in liquid lead containing 10{sup −6} wt% and 10{sup −8} wt% oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Heinzel, A., E-mail: Annette.heinzel@kit.edu [Karlsruher Insitute of Technologie, Institute for Pulsed Power and Microwave Technology, P.O. Box 3640, D-76021 Karlsruhe (Germany); Müller, G.; Weisenburger, A. [Karlsruher Insitute of Technologie, Institute for Pulsed Power and Microwave Technology, P.O. Box 3640, D-76021 Karlsruhe (Germany)

    2013-06-15

    Specimens with welded joints of P91 TIG (tungsten inert gas welding), P91 EB (electron beam welding) and frictions stir welding, with P92 (EB), PM2000 (EB) and combination of P91-PM2000 EB were tested 2000 h in stagnant liquid Pb at 550 °C with an oxygen concentration of 10{sup −6} wt% and 10{sup −8} wt%. After exposure at 10{sup −6} wt% all specimens showed an oxide layer on the surface. If the grain size of the welds varies strongly from that of the bulk material like in the friction stir welds, a change in oxide thickness could be observed. Also precipitations which pin the oxide formers or reduce the diffusion rate can lead to thicker oxide layers or a stronger dissolution attack like it was observed on the dissimilar weld P91/PM2000 EB. The specimens have similar microstructures in all regions (weld, heat affected zone and bulk material) and due to a post-weld heat treatment show everywhere the same behavior.

  19. Welding method, and welding device for use therein, and method of analysis for evaluating welds

    NARCIS (Netherlands)

    Aendenroomer, A.J.; Den Ouden, G.; Xiao, Y.H.; Brabander, W.A.J.

    1995-01-01

    Described is a method of automatically welding pipes, comprising welding with a pulsation welding current and monitoring, by means of a sensor, the variations occurring in the arc voltage caused by weld pool oscillations. The occurrence of voltage variations with only frequency components below 100

  20. Thermoplastic welding apparatus and method

    Energy Technology Data Exchange (ETDEWEB)

    Matsen, Marc R.; Negley, Mark A.; Geren, William Preston; Miller, Robert James

    2017-03-07

    A thermoplastic welding apparatus includes a thermoplastic welding tool, at least one tooling surface in the thermoplastic welding tool, a magnetic induction coil in the thermoplastic welding tool and generally encircling the at least one tooling surface and at least one smart susceptor in the thermoplastic welding tool at the at least one tooling surface. The magnetic induction coil is adapted to generate a magnetic flux field oriented generally parallel to a plane of the at least one smart susceptor.

  1. Laser forming and welding processes

    CERN Document Server

    Yilbas, Bekir Sami; Shuja, Shahzada Zaman

    2013-01-01

    This book introduces model studies and experimental results associated with laser forming and welding such as laser induced bending, welding of sheet metals, and related practical applications. The book provides insight into the physical processes involved with laser forming and welding. The analytical study covers the formulation of laser induced bending while the model study demonstrates the simulation of bending and welding processes using the finite element method. Analytical and numerical solutions for laser forming and welding problems are provided.

  2. Guidelines for Friction Stir Welding

    Science.gov (United States)

    2011-03-29

    in a large void at the termination point of the weld, the effects the exit hole will have on structural integrity must be considered. The...3.6 Cavity. A void -type discontinuity within a solid-state weld. See Figure 3.4. 3.7 Complex weld joint. A continuous weld...except as affected by corner radii. 3.61 Underfill . A depression resulting when the weld face is below the adjacent parent material surface. See

  3. Effect of solution annealing on properties of used reformer centrifugally casted tubes prior to repair by welding

    Directory of Open Access Journals (Sweden)

    B. Mateša

    2014-01-01

    Full Text Available The specimens of damaged tubes, ASTM A297 HK 40, are repaired by welding. Before repairing, solution annealing is used as a procedure for properties restitution. This paper explores the influence of used solution annealing procedure (1 050 şC / 2h on mechanical and micro-structural properties. The emphasis is put on specific procedures at repair by welding.

  4. Elucidation of laser welding phenomena and factors affecting weld penetration and welding defects

    Science.gov (United States)

    Katayama, Seiji; Kawahito, Yousuke; Mizutani, Masami

    The behavior and effect of a plasma plume on the weld penetration are greatly different between CO2 laser welding and YAG, disk or fiber laser welding. The effects of the power and the power density on the weld penetration are elucidated. Spattering leading to the formation of underfilled weld beads is controlled by inclining the laser beam. Porosity is formed from bubbles generated from the tip of the keyhole at low welding speed or from the middle part of the keyhole at high laser power density. Cracking easily occurs in pulsed spot welding of aluminum alloys.

  5. Genomics and museum specimens.

    Science.gov (United States)

    Nachman, Michael W

    2013-12-01

    Nearly 25 years ago, Allan Wilson and colleagues isolated DNA sequences from museum specimens of kangaroo rats (Dipodomys panamintinus) and compared these sequences with those from freshly collected animals (Thomas et al. 1990). The museum specimens had been collected up to 78 years earlier, so the two samples provided a direct temporal comparison of patterns of genetic variation. This was not the first time DNA sequences had been isolated from preserved material, but it was the first time it had been carried out with a population sample. Population geneticists often try to make inferences about the influence of historical processes such as selection, drift, mutation and migration on patterns of genetic variation in the present. The work of Wilson and colleagues was important in part because it suggested a way in which population geneticists could actually study genetic change in natural populations through time, much the same way that experimentalists can do with artificial populations in the laboratory. Indeed, the work of Thomas et al. (1990) spawned dozens of studies in which museum specimens were used to compare historical and present-day genetic diversity (reviewed in Wandeler et al. 2007). All of these studies, however, were limited by the same fundamental problem: old DNA is degraded into short fragments. As a consequence, these studies mostly involved PCR amplification of short templates, usually short stretches of mitochondrial DNA or microsatellites. In this issue, Bi et al. (2013) report a breakthrough that should open the door to studies of genomic variation in museum specimens. They used target enrichment (exon capture) and next-generation (Illumina) sequencing to compare patterns of genetic variation in historic and present-day population samples of alpine chipmunks (Tamias alpinus) (Fig. 1). The historic samples came from specimens collected in 1915, so the temporal span of this comparison is nearly 100 years.

  6. Model of Layered Weld Formation Under Narrow Gap Pulse Welding

    Science.gov (United States)

    Krampit, A. G.

    2016-04-01

    The model parameters of narrow gap pulse welding can be divided into input, internal and output ones. The breadth of gap, that is, clearance breadth between upright edges is one of key parameters securing high quality of a weld joint. The paper presents theoretical outcomes for the model of layered weld formation under narrow gap pulse welding. Based on these studies is developed model of processes, which occur in the weld pool under pulse grove welding. It comprises the scheme of liquid metal motion in the weld pool, scheme of fusion with the side edge and in the bottom part, and the scheme of welding current impulse effect on the structure of a weld joint.

  7. Welding processes handbook

    CERN Document Server

    Weman, Klas

    2003-01-01

    Deals with the main commercially significant and commonly used welding processes. This title takes the student or novice welder through the individual steps involved in each process in an easily understood way. It covers many of the requirements referred to in European Standards including EN719, EN 729, EN 729 and EN 287.$bWelding processes handbook is a concise, explanatory guide to the main commercially significant and commonly-used welding processes. It takes the novice welder or student through the individual steps involved in each process in a clear and easily understood way. It is intended to provide an up-to-date reference to the major applications of welding as they are used in industry. The contents have been arranged so that it can be used as a textbook for European welding courses in accordance with guidelines from the European Welding Federation. Welding processes and equipment necessary for each process are described so that they can be applied to all instruction levels required by the EWF and th...

  8. Application of explosive welding to heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, G.

    1983-10-01

    The subject is discussed under the headings: advantages of explosive welding; principle of explosive welding; explosive welding of tubes; metallurgy of explosive welds (micrographs; microhardness); tubular heat exchangers; plugging; sleeving; retubing; construction of new heat exchangers; thermal sleeves.

  9. Failure Behaviors Depending on the Notch Location of the Impact Test Specimens on the HAZ

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yun Chan; Kim, Dong Wook; Lee, Young Suk [Chungang Univ., Seoul (Korea, Republic of); Hong, Jae Keun; Park, Ji Hong [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2007-07-01

    Numerical studies were performed to examine the effects of notch location of impact specimens on the failure behavior of HAZ (Heat Affected Zone) when Charpy V-notch impact test were made at a low temperature (1 .deg. C). Carbon steel plate (SA-516 Gr. 70) with thickness of 25mm for pressure vessel was welded by SMAW (Shielded Metal-Arc Welding) and specimens were fabricated from the welded plate. Charpy tests were then performed with specimens having different notch positions of specimens varying from the fusion line through HAZ to base metal. A series of finite element analysis which simulates the Charpy test and crack propagation initiating at the tip of V-notch was carried out as well. The finite element analysis takes into account the irregular fusion line and non-homogenous material properties due to the notch location of the specimen in HAZ. Results reveals that the energies absorbed during impact test depend significantly on the notch location and direction of specimen. Finite element analysis also demonstrates that the notch location of specimens, to a great extent, influences the reliability and consistency of the test.

  10. Mechanical properties and long-range behaviour of TZM-welding joints

    Energy Technology Data Exchange (ETDEWEB)

    Jakobeit, W.; Bulla, W.; Eck, R.; Ullrich, G.

    1987-05-01

    In order to utilize the known excellent high temperature properties of TZM (Mo-0,5Ti-0,08Zr) for construction of components with thick sections (sheets of 8 mm wall thickness, bars of 25 mm diameter) the testing of suitable joining techniques was necessary. Based on the present state of the art the EB- and TIG-welding as well as the friction welding seemed to be the qualified methods. The investigations of the welded specimens covered non-destructive tests and metallographic evaluations as well as tensile tests, long term creep rupture tests at 850/sup 0/C and fatigue tests unter tension-compression stresses at room temperature and 850/sup 0/C. EB- and TIG-weldments showed coarse grained weld and heat affected zones. Due to higher gas contents, the EB-welded specimens produced by P/M process were interspersed with pores while the joints of the ARC-cast TZM material were uniform. However, TIG-welds of both variants were affected with porosity and cracks. The friction welds were almost perfect. In the tensile tests, all the joints containing recrystallized microstructure zones ruptured in the welds at strength values equivalent to recrystallized TZM. The strength of friction welds exhibited significant higher values. At room temperature the tensile ductility of all weldments was inadequate, the friction welded specimens showed the lowest values. At 850/sup 0/C the tensile ductility was adequate in all variants. The creep rupture tests at 850/sup 0/C exhibit up to 10,000 h that the strength of the friction weldments exceed those of the EB-weldments. (orig./IHOE).

  11. Thermal stir welding apparatus

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2011-01-01

    A welding method and apparatus are provided for forming a weld joint between first and second elements of a workpiece. The method includes heating the first and second elements to form an interface of material in a plasticized or melted state interface between the elements. The interface material is then allowed to cool to a plasticized state if previously in a melted state. The interface material, while in the plasticized state, is then mixed, for example, using a grinding/extruding process, to remove any dendritic-type weld microstructures introduced into the interface material during the heating process.

  12. Thermal stir welding process

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2012-01-01

    A welding method is provided for forming a weld joint between first and second elements of a workpiece. The method includes heating the first and second elements to form an interface of material in a plasticized or melted state interface between the elements. The interface material is then allowed to cool to a plasticized state if previously in a melted state. The interface material, while in the plasticized state, is then mixed, for example, using a grinding/extruding process, to remove any dendritic-type weld microstructures introduced into the interface material during the heating process.

  13. Fusion Welding Research.

    Science.gov (United States)

    2014-09-26

    RD-AlSO 253 FUSION WELDING RESEARCH(U) MASSACHUSETTS INST OF TECH L/I CAMBRIDGE DEPT OF MATERIALS SCIENCE AND ENGINEERING T W EAGAR ET AL. 30 RPR 85...NUMBER 12. GOV’ ACCESSION NO. 3. RECICIE-S CATALOG NUMBER 4. T TL V nd Subtitle) S. P OFRPR PERIOD COVERED 5t h A~nnual Technical Report Fusion Welding ...research S on welding processes. Studies include metal vapors in the arc, development of a high speed infrared temperature monitor, digital signal

  14. Review of Welding Terminology

    Directory of Open Access Journals (Sweden)

    Angelika Petrėtienė

    2011-04-01

    Full Text Available The paper discusses welding terms in accordance with the Lithuanian standard LST EN 1792 „Welding. The multilingual list of welding terms and similar processes”, „The Russian–Lithuanian dictionary of the terms of mechanical engineering technology and welding“ and the examples from postgraduates‘ final works. It analyses the infringement of lexical, word-building and morphological rules. First-year students should already be familiar with the standardized terms of their speciality. More active propagation of the terms should help to avoid terminology mistakes in various scientific spheres.

  15. Hybrid laser-arc welding

    DEFF Research Database (Denmark)

    Hybrid laser-arc welding (HLAW) is a combination of laser welding with arc welding that overcomes many of the shortfalls of both processes. This important book gives a comprehensive account of hybrid laser-arc welding technology and applications. The first part of the book reviews...... the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

  16. [Blood Count Specimen].

    Science.gov (United States)

    Tamura, Takako

    2015-12-01

    The circulating blood volume accounts for 8% of the body weight, of which 45% comprises cellular components (blood cells) and 55% liquid components. We can measure the number and morphological features of blood cells (leukocytes, red blood cells, platelets), or count the amount of hemoglobin in a complete blood count: (CBC). Blood counts are often used to detect inflammatory diseases such as infection, anemia, a bleeding tendency, and abnormal cell screening of blood disease. This count is widely used as a basic data item of health examination. In recent years, clinical tests before consultation have become common among outpatient clinics, and the influence of laboratory values on consultation has grown. CBC, which is intended to count the number of raw cells and to check morphological features, is easily influenced by the environment, techniques, etc., during specimen collection procedures and transportation. Therefore, special attention is necessary to read laboratory data. Providing correct test values that accurately reflect a patient's condition from the laboratory to clinical side is crucial. Inappropriate medical treatment caused by erroneous values resulting from altered specimens should be avoided. In order to provide correct test values, the daily management of devices is a matter of course, and comprehending data variables and positively providing information to the clinical side are important. In this chapter, concerning sampling collection, blood collection tubes, dealing with specimens, transportation, and storage, I will discuss their effects on CBC, along with management or handling methods.

  17. Friction stir welding tool

    Science.gov (United States)

    Tolle; Charles R. , Clark; Denis E. , Barnes; Timothy A.

    2008-04-15

    A friction stir welding tool is described and which includes a shank portion; a shoulder portion which is releasably engageable with the shank portion; and a pin which is releasably engageable with the shoulder portion.

  18. Magnetic Pulse Welding Technology

    Directory of Open Access Journals (Sweden)

    Ahmad K. Jassim

    2011-12-01

    Full Text Available In this paper, the benefits of using Magnetic Pulse machine which is belong to Non-conventional machine instead of conventional machine. Magnetic Pulse Technology is used for joining dissimilar metals, and for forming and cutting metals. It is a non contact technique. Magnetic field is used to generate impact magnetic pressure for welding and forming the work piece by converted the electrical energy to mechanical energy. It is enable us to design previously not possible by welding dissimilar materials and allowing to welds light and stronger materials together. It can be used to weld metallic with non metallic materials to created mechanical lock on ceramics, polymers, rubbers and composites. It is green process; there is no heat, no radiation, no gas, no smoke and sparks, therefore the emissions are negligible.

  19. Parametric studies on tensile strength in joining AA6061- T6 and AA7075-T6 by gas metal arc welding process

    Science.gov (United States)

    Ishak, M.; Noordin, N. F. M.; Shah, L. H.

    2015-12-01

    Proper selection of the welding parameters can result in better joining. In this study, the effects of various welding parameters on tensile strength in joining dissimilar aluminum alloys AA6061-T6 and AA7075-T6 were investigated. 2 mm thick samples of both base metals were welded by semi-automatic gas metal arc welding (GMAW) using filler wire ER5356. The welding current, arc voltage and welding speed were chosen as variables parameters. The strength of each specimen after the welding operations were tested and the effects of these parameters on tensile strength were identified by using Taguchi method. The range of parameter for welding current were chosen from 100 to 115 A, arc voltage from 17 to 20 V and welding speed from 2 to 5 mm/s. L16 orthogonal array was used to obtained 16 runs of experiments. It was found that the highest tensile strength (194.34 MPa) was obtained with the combination of a welding current of 115 A, welding voltage of 18 V and welding speed of 4 mm/s. Through analysis of variance (ANOVA), the welding voltage was the most effected parameter on tensile strength with percentage of contribution at 41.30%.

  20. Contact Modelling in Resistance Welding, Part II: Experimental Validation

    DEFF Research Database (Denmark)

    Song, Quanfeng; Zhang, Wenqi; Bay, Niels

    2006-01-01

    Contact algorithms in resistance welding presented in the previous paper are experimentally validated in the present paper. In order to verify the mechanical contact algorithm, two types of experiments, i.e. sandwich upsetting of circular, cylindrical specimens and compression tests of discs...... with a solid ring projection towards a flat ring, are carried out at room temperature. The complete algorithm, involving not only the mechanical model but also the thermal and electrical models, is validated by projection welding experiments. The experimental results are in satisfactory agreement...

  1. Modeling the damage of welded steel, using the GTN model

    Directory of Open Access Journals (Sweden)

    El-Ahmar Kadi

    2014-11-01

    Full Text Available The aim of our work is the modeling of the damage in the weld metal according to the finite element method and the concepts of fracture mechanics based on local approaches using the code ABAQUS calculates. The use of the Gurson-Tvergaard-Needleman model axisymmetric specimens AE type to three different zones (Base metal, molten metal and heat affected Zone with four levels of triaxiality (AE2, AE4, AE10 and AE80, we have used to model the behavior of damage to welded steel, which is described as being due to the growth and coalescence of cavities with high rates of triaxiality

  2. Explosive Welding with Nitroguanidine.

    Science.gov (United States)

    Sadwin, L D

    1964-03-13

    By using the explosive nitroguanidine, continuous welds can be made between similar and dissimilar metals. Since low detonation pressures are attainable, pressure transfer media are not required between the explosive and the metal surface. The need for either a space or an angle between the metals is eliminated, and very low atmospheric pressures are not required. Successful welds have been made between tantalum and 4140 steel, 3003H14 aluminum and 4140 steel, and 304 stainless steel and 3003H14 aluminum.

  3. Laser Impact Welding

    OpenAIRE

    Daehn, Glenn S.; Lippold, John; Liu, Deijan; Taber, Geoff; Wang, Huimin

    2012-01-01

    Laser impact welding is a solid-state, collision-based welding process. In this process, laser-generated optical energy is converted to kinetic energy through the ablation at the surface and confinement of the gas generated between a flyer and backing plate. The launch of the flyer can be affected by many factors, for example, backing material, ablative layer, and flyer thickness. In this paper, the effect of three backing materials: glass, polycarbonate and cellophane tape, we...

  4. Welding of solid wood

    OpenAIRE

    Ivica Župčić; Goran Mihulja; Andrija Bogner; Ivica Grbac; Ivica @up~i}, Goran Mihulja, Andrija Bogner, Ivica Grbac,; Božidar Hrovat

    2008-01-01

    This paper presents the up-to-date knowledge and results of the application of wood welding techniques at the Faculty of Forestry University of Zagreb. Wood welding technologies have been developed as a new way of bonding timber by using high temperature generatedby friction and pressure. Timber is assembled without any adhesives. During the process the surface layer of timber (lignin), which is in direct contact with its counterpart, melts due to high pressure and temperature, which is usual...

  5. The effect of electron beam welding on the creep rupture properties of a Nb-Zr-C alloy

    Science.gov (United States)

    Moore, T. J.; Titran, R. H.; Grobstein, T. L.

    1986-01-01

    Creep rupture tests of electron beam welded PWC-11 sheet were conducted at 1350 K. Full penetration, single pass welds were oriented transverse to the testing direction in 1 mm thick sheet. With this orientation, stress was imposed equally on the base metal, weld metal, and heat-affected zone. Tests were conducted in both the postweld annealed and aged conditions. Unwelded specimens with similar heat treatments were tested for comparative purposes. It was found that the weld region is stronger than the base metal for both the annealed and aged conditions and that the PWC-11 material is stronger in the annealed condition than in the aged condition.

  6. Effects of stop-start features on residual stresses in a multipass austenitic stainless steel weld

    Energy Technology Data Exchange (ETDEWEB)

    Turski, M., E-mail: Mark.Turski@magnesium-elektron.com [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Francis, J.A. [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom)] [Materials Engineering, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Hurrell, P.R. [Rolls-Royce Plc., Raynesway, Derby DE21 7XX (United Kingdom); Bate, S.K. [Serco Technical Services, Birchwood Park, Warrington, Cheshire WA3 6GA (United Kingdom); Hiller, S. [Materials Engineering, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Withers, P.J. [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom)

    2012-01-15

    In this article we describe experiments that characterise and quantify the localised perturbations in residual stress associated with both ramped and abrupt stop-start features in a multipass weld. Residual stress distributions in AISI Grade 304L/308L stainless steel groove-welded specimens, containing weld interruptions that were introduced in a controlled manner, have been characterised using both neutron diffraction and the incremental deep hole drilling method. The extent to which the localised stresses associated with the interruptions were annealed by overlayed passes was also assessed. The results suggest that, regardless of the type of interruption, there can be significant localised increases in residual stress if the stop-start feature is left exposed. If further weld passes are deposited, then the localised increases in stress are likely to persist if the interruption was abrupt, whereas for a ramped interruption they may be dissipated. - Highlights: Black-Right-Pointing-Pointer In this study the residual stress-field surrounding weld interruptions was measured. Black-Right-Pointing-Pointer Localised stresses were found to increase at weld interruptions. Black-Right-Pointing-Pointer Both ramped and abrupt weld interruptions were investigated. Black-Right-Pointing-Pointer After subsequent weld passes, localised stresses persisted for abrupt interruptions. Black-Right-Pointing-Pointer After subsequent weld passes, localised stresses dissipated for ramped interruptions.

  7. Friction Stir-Welded Titanium Alloy Ti-6Al-4V: Microstructure, Mechanical and Fracture Properties

    Science.gov (United States)

    Sanders, D. G.; Edwards, P.; Cantrell, A. M.; Gangwar, K.; Ramulu, M.

    2015-05-01

    Friction stir welding (FSW) has been refined to create butt welds from two sheets of Ti-6Al-4V alloy to have an ultra-fine grain size. Weld specimen testing was completed for three different FSW process conditions: As welded, stress relieved, stress relieved and machined, and for the un-welded base material. The investigation includes macrostructure, microstructure, microhardness, tensile property testing, notched bar impact testing, and fracture toughness evaluations. All experiments were conducted in accordance with industry standard testing specifications. The microstructure in the weld nugget was found to consist of refined and distorted grains of alpha in a matrix of transformed beta containing acicular alpha. The enhanced fracture toughness of the welds is a result of increased hardness, which is attributed to an increase in alpha phase, increase in transformed beta in acicular alpha, and grain refinement during the weld process. The noted general trend in mechanical properties from as welded, to stress relieved, to stress relieved and machined conditions exhibited a decrease in ultimate tensile strength, and yield strength with a small increase in ductility and a significant increase in fracture toughness.

  8. Specimen Holder For Flammability Tests

    Science.gov (United States)

    Rucker, Michelle A.

    1992-01-01

    Fixture holds sheet specimens for flammability tests. Frame and clamps designed to minimize local overstress on specimen. Heat capacity of fixture low, interfering less with interpretation of results of test by drawing less heat away from specimen. Accepts films, fabrics, foams, and other sheets, rigid or flexible. Specimens thin or thick, or of variable thickness. Bent to accommodate curved rigid specimens. Also used for such other tests as particle-impact tests.

  9. An Analysis of the Weldability of Ductile Cast Iron Using Inconel 625 for the Root Weld and Electrodes Coated in 97.6% Nickel for the Filler Welds

    Directory of Open Access Journals (Sweden)

    Francisco-Javier Cárcel-Carrasco

    2016-11-01

    Full Text Available This article examines the weldability of ductile cast iron when the root weld is applied with a tungsten inert gas (TIG welding process employing an Inconel 625 source rod, and when the filler welds are applied with electrodes coated with 97.6% Ni. The welds were performed on ductile cast iron specimen test plates sized 300 mm × 90 mm × 10 mm with edges tapered at angles of 60°. The plates were subjected to two heat treatments. This article analyzes the influence on weldability of the various types of electrodes and the effect of preheat treatments. Finally, a microstructure analysis is made of the material next to the weld in the metal-weld interface and in the weld itself. The microstructure produced is correlated with the strength of the welds. We treat an alloy with 97.6% Ni, which prevents the formation of carbides. With a heat treatment at 900 °C and 97.6% Ni, there is a dissolution of all carbides, forming nodules in ferritic matrix graphite.

  10. Laser Peening and Shot Peening Effects on Fatigue Life and Surface Roughness of Friction Stir Welded 7075-T7351 Aluminum

    Science.gov (United States)

    Hatamleh, Omar; Lyons, Jed; Forman, Royce

    2006-01-01

    The effects of laser peening, shot peening, and a combination of both on the fatigue life of Friction Stir Welds (FSW) was investigated. The fatigue samples consisted of dog bone specimens and the loading was applied in a direction perpendicular to the weld direction. Several laser peening conditions with different intensities, durations, and peening order were tested to obtain the optimum peening parameters. The surface roughness resulting from various peening techniques was assessed and characterized. The results indicate a significant increase in fatigue life using laser peening compared to shot peened versus their native welded specimens.

  11. NASA Biological Specimen Repository

    Science.gov (United States)

    McMonigal, K. A.; Pietrzyk, R. A.; Sams, C. F.; Johnson, M. A.

    2010-01-01

    The NASA Biological Specimen Repository (NBSR) was established in 2006 to collect, process, preserve and distribute spaceflight-related biological specimens from long duration ISS astronauts. This repository provides unique opportunities to study longitudinal changes in human physiology spanning may missions. The NBSR collects blood and urine samples from all participating ISS crewmembers who have provided informed consent. These biological samples are collected once before flight, during flight scheduled on flight days 15, 30, 60, 120 and within 2 weeks of landing. Postflight sessions are conducted 3 and 30 days after landing. The number of in-flight sessions is dependent on the duration of the mission. Specimens are maintained under optimal storage conditions in a manner that will maximize their integrity and viability for future research The repository operates under the authority of the NASA/JSC Committee for the Protection of Human Subjects to support scientific discovery that contributes to our fundamental knowledge in the area of human physiological changes and adaptation to a microgravity environment. The NBSR will institute guidelines for the solicitation, review and sample distribution process through establishment of the NBSR Advisory Board. The Advisory Board will be composed of representatives of all participating space agencies to evaluate each request from investigators for use of the samples. This process will be consistent with ethical principles, protection of crewmember confidentiality, prevailing laws and regulations, intellectual property policies, and consent form language. Operations supporting the NBSR are scheduled to continue until the end of U.S. presence on the ISS. Sample distribution is proposed to begin with selections on investigations beginning in 2017. The availability of the NBSR will contribute to the body of knowledge about the diverse factors of spaceflight on human physiology.

  12. Modelling of Specimen Fracture

    Science.gov (United States)

    2013-09-23

    the plate center. An end load of 1.0 MPa was applied. 1 2 3 Modelling of Specimen Fracture – Final Report 11 TR-13-47 Figure 2.5: Crack Geometry Figure...Christopher Bayley DRDC Atlantic Dockyard Laboratory Pacific CFB Esquimalt, Building 199 PO Box 17000, Station Forces Victoria, British Columbia Canada...q The weighting function, q , can be any arbitrary function within the J-integral domain, and must be zero on the domain boundary . An easy function

  13. Labeling of Patient Specimens

    Science.gov (United States)

    2011-01-26

    noted during the event that the actu.al number of near miss incidmts reported monthly was low due to laboratory personnel performing rounds each...specimens never leaves label and if moved it is labeled), All orders in system and all near misses and errors reported to patient safety Purchase/Install...Meeting 14 Aug 09, 1400 in lab break room thru out Develop TICK sheet to track near misses .JDI Ms. Clark Clinics will provide toPS 1st working day of

  14. Certification of a weld produced by friction stir welding

    Science.gov (United States)

    Obaditch, Chris; Grant, Glenn J

    2013-10-01

    Methods, devices, and systems for providing certification of friction stir welds are disclosed. A sensor is used to collect information related to a friction stir weld. Data from the sensor is compared to threshold values provided by an extrinsic standard setting organizations using a certification engine. The certification engine subsequently produces a report on the certification status of the weld.

  15. Welding state of art for Eurofer 97 application to Tritium Blanket Module for ITER Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, P. [CEA Saclay, Dept. Modelisation de Systemes et Structures (DEN/DANS/DM2S/DIR), 91 - Gif sur Yvette (France); Janin, F. [CEA Saclay, Dept. Modelisation de Systemes et Structures (DEN/DANS/DPC/SCP/Gerailp), 91 - Gif sur Yvette (France)

    2007-07-01

    stage. For TIG and laser processes, no metallurgical defect or damage has been observed. HAZ and Fusion Zones are larger in TIG welds compared with laser welds. Six TIG welding passes are necessary, compared to the two passes for laser process. For laser and Hybrid (MIG/Laser) welding process, joint coefficient can be considered as 1. All tensile specimens have broken outside the welds, and in the parent base material. For laser welds, tempering Post Welding Heat Treatment has markedly reduced the hardening level in fusion zone, to acceptable values in the range of 300 HV 10. Impact tests have shown good results. Welding simulation has been carried out, and numerical martensitic weld width is close to real one. (authors)

  16. Experimental investigation of explosive welding of cp-titanium/AISI 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Akbari Mousavi, S.A.A. [School of Metallurgy and Materials Engineering, University College of Engineering, University of Tehran, P.O. Box 11365-4563, Tehran (Iran, Islamic Republic of)], E-mail: akbarimusavi@ut.ac.ir; Farhadi Sartangi, P. [School of Metallurgy and Materials Engineering, University College of Engineering, University of Tehran, P.O. Box 11365-4563, Tehran (Iran, Islamic Republic of)], E-mail: farhadi_pezhman@engmail.ut.ac.ir

    2009-03-15

    In explosive welding process, the controlled energy of explosives is used to create a metallurgical bond between two similar or dissimilar materials. This paper presents the analytical calculation for determination of weldability domain or welding window. The analytical calculations are in good agreement with experimental results. The welding conditions are tailored through parallel geometry route with different explosive loads. The study was also conducted to consider the effects of explosive loading on the bonding interface and the characterization of explosive welding experiments carried out under different conditions. Optical microscopy studies show that a transition from a smooth interface to a wavy one occurs with increase in explosive load. Scanning electron microscopy studies show that the interface was outlined by characteristic sharp transition between two materials, but local melted zones were also encountered in the front slope of waves in the interface at high explosive loads. XRD studies detected no intermetallic phases for specimen welded at low explosive load.

  17. Welding sequence effects on residual stress distribution in offshore wind monopile structures

    Directory of Open Access Journals (Sweden)

    Ali Mehmanparast

    2016-01-01

    Full Text Available Residual stresses are often inevitably introduced into the material during the fabrication processes, such as welding, and are known to have significant effects on the subsequent fatigue crack growth behavior of welded structures. In this paper, the importance of welding sequence on residual stress distribution in engineering components has been reviewed. In addition, the findings available in the literature have been used to provide an accurate interpretation of the fatigue crack growth data on specimens extracted from the welded plates employed in offshore wind monopile structures. The results have been discussed in terms of the role of welding sequence in damage inspection and structural integrity assessment of offshore renewable energy structures.

  18. Laser Deep Penetration Welding of an Aluminum Alloy with Simultaneously Applied Vibrations

    Science.gov (United States)

    Woizeschke, Peer; Radel, Tim; Nicolay, Paul; Vollertsen, Frank

    2016-12-01

    In aluminum welding, the grain structure of produced seams is an essential factor with respect to the seam properties. In the casting technology the effect of mechanical vibrations on the grain growth during the solidification of liquid metals is known as a refinement method. In this paper, the transferability of this approach from comparatively long-time processes in the field of casting to the short-time process of laser deep penetration welding is investigated. Therefore, specimens were sinusoidal vibrated with frequencies up to 4 kHz during bead-on-plate full-penetration welding experiments. The resulting grain size was determined by applying the circular intercept procedure on the center of a cross-section micrograph of each weld. The results show that grain refinement is in general achievable by mechanical vibrations in the audible frequency range during laser full penetration keyhole welding of the aluminum alloy EN AW-5083.

  19. Self-Reacting Friction Stir Welding for Aluminum Alloy Circumferential Weld Applications

    Science.gov (United States)

    Bjorkman, Gerry; Cantrell, Mark; Carter, Robert

    2003-01-01

    Friction stir welding is an innovative weld process that continues to grow in use, in the commercial, defense, and space sectors. It produces high quality and high strength welds in aluminum alloys. The process consists of a rotating weld pin tool that plasticizes material through friction. The plasticized material is welded by applying a high weld forge force through the weld pin tool against the material during pin tool rotation. The high weld forge force is reacted against an anvil and a stout tool structure. A variation of friction stir welding currently being evaluated is self-reacting friction stir welding. Self-reacting friction stir welding incorporates two opposing shoulders on the crown and root sides of the weld joint. In self-reacting friction stir welding, the weld forge force is reacted against the crown shoulder portion of the weld pin tool by the root shoulder. This eliminates the need for a stout tooling structure to react the high weld forge force required in the typical friction stir weld process. Therefore, the self-reacting feature reduces tooling requirements and, therefore, process implementation costs. This makes the process attractive for aluminum alloy circumferential weld applications. To evaluate the application of self-reacting friction stir welding for aluminum alloy circumferential welding, a feasibility study was performed. The study consisted of performing a fourteen-foot diameter aluminum alloy circumferential demonstration weld using typical fusion weld tooling. To accomplish the demonstration weld, weld and tack weld development were performed and fourteen-foot diameter rings were fabricated. Weld development consisted of weld pin tool selection and the generation of a process map and envelope. Tack weld development evaluated gas tungsten arc welding and friction stir welding for tack welding rings together for circumferential welding. As a result of the study, a successful circumferential demonstration weld was produced leading

  20. Welding defects at friction stir welding

    Directory of Open Access Journals (Sweden)

    P. Podržaj

    2015-04-01

    Full Text Available The paper presents an overview of different types of defects at friction stir welding. In order to explain the reasons for their occurrence a short theoretical background of the process is given first. The main emphasis is on the parameters that influence the process. An energy supply based division of defects into three disjoint groups was used. The occurring defects are demonstrated on various materials.

  1. Composite Aluminum-Copper Sheet Material by Friction Stir Welding and Cold Rolling

    OpenAIRE

    Kahl, S; Osikowicz, W

    2013-01-01

    An aluminum alloy and a pure copper material were butt-joined by friction stir welding and subsequently cold rolled. The cold-rolling operation proved to be very advantageous because small voids present after friction stir welding were closed, the interface area per material thickness was enlarged, a thin intermetallic layer was partitioned, and the joint was strengthened by strain hardening. Tensile test specimens fractured in the heat-affected zone in the aluminum material; tensile strength...

  2. The influence of the heat treatment on delta ferrite transformation in austenitic stainless steel welds

    Directory of Open Access Journals (Sweden)

    B. Mateša

    2012-04-01

    Full Text Available Shielded metal arc (SMAW welded specimens using austenitic consumable materials with different amount of delta-ferrite are annealed in range 650-750 °C through 2-10 hours. Factorial plan 33 with influenced factors regression analyze of measured delta-ferrite values is used. The transformation i.e. decomposition of delta ferrite during annealing was analyzed regarding on weld cracking resistance using metallographic examination and WRC-1992 diagram.

  3. Re-analysis of fatigue data for welded joints using the notch stress approach

    DEFF Research Database (Denmark)

    Pedersen, Mikkel Melters; Mouritsen, Ole Ø.; Hansen, Michael Rygaard

    2010-01-01

    Experimental fatigue data for welded joints have been collected and subjected to re-analysis using the notch stress approach according to IIW recommendations. This leads to an overview regarding the reliability of the approach, based on a large number of results (767 specimens). Evidently......-welded joints agree quite well with the FAT 225 curve; however a reduction to FAT 200 is suggested in order to achieve approximately the same safety as observed in the nominal stress approach....

  4. Study of Radiographic Linear Indications and Subsequent Microstructural Features in Gas Tungsten Arc Welds of Inconel 718

    Science.gov (United States)

    Walley, J. L.; Nunes, A. C.; Clounch, J. L.; Russell, C. K.

    2007-01-01

    This study presents examples and considerations for differentiating linear radiographic indications produced by gas tungsten arc welds in a 0.05-in-thick sheet of Inconel 718. A series of welds with different structural features, including the enigma indications and other defect indications such as lack of fusion and penetration, were produced, radiographed, and examined metallographically. The enigma indications were produced by a large columnar grain running along the center of the weld nugget occurring when the weld speed was reduced sufficiently below nominal. Examples of respective indications, including the effect of changing the x-ray source location, are presented as an aid to differentiation. Enigma, nominal, and hot-weld specimens were tensile tested to demonstrate the harmlessness of the enigma indication. Statistical analysis showed that there is no difference between the strengths of these three weld conditions.

  5. Welding. Performance Objectives. Intermediate Course.

    Science.gov (United States)

    Vincent, Kenneth

    Several intermediate performance objectives and corresponding criterion measures are listed for each of nine terminal objectives for an intermediate welding course. The materials were developed for a 36-week (3 hours daily) course designed to prepare the student for employment in the field of welding. Electric welding and specialized (TIG & MIG)…

  6. Welding. Performance Objectives. Basic Course.

    Science.gov (United States)

    Vincent, Kenneth

    Several intermediate performance objectives and corresponding criterion measures are listed for each of eight terminal objectives for a basic welding course. The materials were developed for a 36-week (2 hours daily) course developed to teach the fundamentals of welding shop work, to become familiar with the operation of the welding shop…

  7. Designing aluminium friction stir welded joints against multiaxial fatigue

    Directory of Open Access Journals (Sweden)

    L. Susmel

    2016-07-01

    Full Text Available The present paper investigates the accuracy of the Modified Wöhler Curve Method (MWCM in estimating multiaxial fatigue strength of aluminium friction stir (FS welded joints. Having developed a bespoke joining technology, circumferentially FS welded tubular specimens of Al 6082-T6 were tested under proportional and non-proportional tension and torsion, the effect of non-zero mean stresses being also investigated. The validation exercise carried out using the experimental results have demonstrated that the MWCM applied in terms of nominal stresses, notch stresses, and also the Point Method is accurate in predicting the fatigue lifetime of the tested FS welded joints, with its use resulting in life estimates that fall within the uniaxial and torsional calibration scatter bands.

  8. Multiaxial fatigue of aluminium friction stir welded joints: preliminary results

    Directory of Open Access Journals (Sweden)

    D. G. Hattingh

    2015-07-01

    Full Text Available The aim of the present research is to check the accuracy of the Modified Wöhler Curve Method (MWCM in estimating the fatigue strength of friction stir (FS welded tubular joints of Al 6082-T6 subjected to in-phase and out-of-phase multiaxial fatigue loading. The welded samples being investigated were manufactured by equipping an MTS I-STIR process development system with a retracting tool that was specifically designed and optimised for this purpose. These specimens were tested under proportional and non-proportional tension and torsion, the effect of non-zero mean stresses being also investigated. The validation exercise carried out by using the generated experimental results allowed us to prove that the MWCM (applied in terms of nominal stresses is highly accurate in predicting the fatigue strength of the tested FS welded joints, its usage resulting in estimates falling with the uniaxial and torsional calibration scatter bands.

  9. ON INTELLIGENTIZED TECHNOLOGIES FOR MODERN WELDING MANUFACTURING

    Institute of Scientific and Technical Information of China (English)

    Chen Shanben; Qiu Tao; Lin Tao; Wu Yixiong

    2003-01-01

    A short survey on researching and developing status of intelligent technologies in modem welding manufacturing is given. According to the developing trend of advanced manufacturing technology, a concept on intelligentized welding manufacturing engineering (IWME), is presented for systematization of researching and developing domains on welding automation, intelligentized welding,robotic and flexible welding and advanced welding manufacturing technologies. And key technologies of welding intelligent manufacturing and its developing trend in the future are investigated.

  10. Friction stir welding tool and process for welding dissimilar materials

    Science.gov (United States)

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

    2013-05-07

    A friction stir welding tool and process for lap welding dissimilar materials are detailed. The invention includes a cutter scribe that penetrates and extrudes a first material of a lap weld stack to a preselected depth and further cuts a second material to provide a beneficial geometry defined by a plurality of mechanically interlocking features. The tool backfills the interlocking features generating a lap weld across the length of the interface between the dissimilar materials that enhances the shear strength of the lap weld.

  11. Mechanical Properties and Fracture Behaviour of LMD Produced 2.4682 and Wrought 2.4630 Dissimilar Welds

    Science.gov (United States)

    Dahmen, Martin; Göbel, Marco

    A bearing made of Stellite 31 (2.4682) has to be welded onto a housing of Nimonic 75 (2.4630) by autogenous laser beam welding. The bearing part is produced by laser metal deposition (LMD), the housing consists of wrought sheet metal. An investigation is undertaken in order to study the effect of the anisotropy of the LMD part on the weld quality. Tensile specimens were produced and tested under varying load directions and test temperatures, and application of different weld heat treatments. The fractured specimens were analysed by metallography and fractography. Tensile tests at room temperature show a dependency of the fracture location and the mode of failure on the load direction with respect to the layer direction in conjunction with the heat treatment. At elevated temperature of 750° all specimens broke in the base material of 2.4630 in ductile fracture mode. Strength measured supersedes the values of either of the base materials.

  12. The interfacial structure of plated copper alloy resistance spot welded joint

    Science.gov (United States)

    Wu, Jingwei; Zhai, Guofu; Chen, Qing; Wang, Jianqi; Ren, Gang

    2008-09-01

    Plated copper alloys are widely used in electron industry. The plating lay caused the farther decreasing of the welding property of copper alloys, whose intrinsic weldability was poor. In this paper, the bronze and brass specimens with nickel-tin double plating layer were joined by resistance spot welding method. The microstructure and peel strength of the joints were investigated. The experiment results show that a sandwich-like structure was obtained in the faying surface after welding, and the nickel plating layer thickness had severe effect on the reliability of the joints.

  13. The interfacial structure of plated copper alloy resistance spot welded joint

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jingwei [Xiamen Hongfa Electroacoustic Co., Ltd, 361021 Xiamen (China); Harbin Institute of Technology, 150001 Harbin (China)], E-mail: jingweiwu.hit@gmail.com; Zhai Guofu [Harbin Institute of Technology, 150001 Harbin (China); Chen Qing; Wang Jianqi; Ren Gang [Xiamen Hongfa Electroacoustic Co., Ltd, 361021 Xiamen (China)

    2008-09-15

    Plated copper alloys are widely used in electron industry. The plating lay caused the farther decreasing of the welding property of copper alloys, whose intrinsic weldability was poor. In this paper, the bronze and brass specimens with nickel-tin double plating layer were joined by resistance spot welding method. The microstructure and peel strength of the joints were investigated. The experiment results show that a sandwich-like structure was obtained in the faying surface after welding, and the nickel plating layer thickness had severe effect on the reliability of the joints.

  14. The reliability of the repair weld joints of aged high temperature components in fossil power boilers

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, Hiroyuki [Science Univ. of Tokyo (Japan); Ohtani, Ryuichi [Kyoto Univ. (Japan); Fujii, Kazuya [Japan Power Engineering and Inspection Corp., Tokyo (Japan); Yokoyama, Tomomitsu; Nishimura, Nobuhiko [Mitsubishi Heavy Industries Ltd., Tokyo (Japan); Suzuki, Komei [Japan Steel Works Ltd., Tokyo (Japan)

    1998-11-01

    It is of fundamental engineering importance to be able to give reliable assessments of the effective service life of the critical components used within fossil power plants, particularly for those operating for prolonged periods. It is common practice for such assessments to have been estimated using destructive tests, typically the stress rupture test, this having been recognized as one of the most reliable evaluation methods available. Its only drawback is that it often does not permit the component to be in use following the sampling of the test specimen without repairing. The current piece of work focuses on the reliability of the repair welds of components for specimens taken from fossil power plants, having been in service for prolonged periods. Several such repairs to welds have been made to an old power boiler, in particular to a superheater header which is fabricated from 2.25Cr-1Mo steel. Under close examination the repairs to the girth weldment showed susceptibilities of weld cracking, similar to that observed in as-manufactured material. Within the repaired region of the welded joint the microstructure, tensile properties and toughness seemed to be unaffected. The hardness attained its minimum value within the heat affected zone, HAZ of the repair weld, overlapping that of original girth weld HAZ. Furthermore, the stress rupture strength achieved its minimum value at the same position taking on the same value as the strength associated with the aged girth welded joint. (orig.)

  15. FEM Analysis and Measurement of Residual Stress by Neutron Diffraction on the Dissimilar Overlay Weld Pipe

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kang Soo; Lee, Ho Jin; Woo, Wan Chuck; Seong, Baek Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Byeon, Jin Gwi; Park, Kwang Soo; Jung, In Chul [Doosan Heavy Industries and Construction Co., Changwon (Korea, Republic of)

    2010-10-15

    Much research has been done to estimate the residual stress on a dissimilar metal weld. There are many methods to estimate the weld residual stress and FEM (Finite Element Method) is generally used due to the advantage of the parametric study. And the X-ray method and a Hole Drilling technique for an experimental method are also usually used. The aim of this paper is to develop the appropriate FEM model to estimate the residual stresses of the dissimilar overlay weld pipe. For this, firstly, the specimen of the dissimilar overlay weld pipe was manufactured. The SA 508 Gr3 nozzle, the SA 182 safe end and SA376 pipe were welded by the Alloy 182. And the overlay weld by the Alloy 52M was performed. The residual stress of this specimen was measured by using the Neutron Diffraction device in the HANARO (High-flux Advanced Neutron Application ReactOr) research reactor, KAERI (Korea Atomic Energy Research Institute). Secondly, FEM Model on the dissimilar overlay weld pipe was made and analyzed by the ABAQUS Code (ABAQUS, 2004). Thermal analysis and stress analysis were performed, and the residual stress was calculated. Thirdly, the results of the FEM analysis were compared with those of the experimental methods

  16. Failure Analysis of Electron Beam Weld Joints for 18Ni Co-free Maraging Steels

    Institute of Scientific and Technical Information of China (English)

    莫德锋; HU; Zheng-fei; WANG; Chun-xu; HE; Guo-qiu

    2007-01-01

    Microstructure of two different 18Ni Co-free maraging specimens and their electron beam weld joints were investigated comparatively by optical microscopy and SEM. It is showing that both of the steels are typical lath martensite, however, one grain size is about three times as another one, and XRD reveals that the amount of the retained austenitic phase in the former is less then the latter. The austenite distributes in plate form along granular and lath boundaries while some in fine particle within the matrix. The microstructural difference between two specimens led to diverse behaviors in electron beam welding. The first specimen is weldable well but the second shows obvious welding defects of pits and burn-through holes in weld face. The welding microstructure exhibits a typical dendritic morphology, and the grains in the heat-affected zone recrystallized and grew up obviously for high temperature heated by welding electron beam. The weldablity is relative to the thermal conduction performance of the base materials,which is contributed greatly for grain size and austenite content.

  17. Mechanical and microstructural characterization of single and double pass Aluminum AA6061 friction stir weld joints

    Science.gov (United States)

    Othman, N. H.; Shah, L. H.; Ishak, M.

    2015-12-01

    This study focuses on the effect of single pass (SP), double sided pass (DSP) and normal double pass (NDP) method on friction stir welding of aluminum AA6061. Two pieces of AA6061 alloy with thickness of 6 mm were friction stir welded by using conventional milling machine. The rotational speeds that were used in this study were 800 rpm, 1000 rpm and 1200 rpm, respectively. The welding speed is fixed to 100 mm/min. Microstructure observation of welded area was studied by using optical microscope. Tensile test and Vickers hardness test were used to evaluate the mechanical properties of this specimen. Mechanical property analysis results indicate that at low rotational speeds, defects such as surface lack of fill and tunneling in the welded area can be observed. Vickers hardness of specimens however did not vary much when rotational speed is varied. Welded specimens using single pass method shows higher tensile strength and hardness value compared to both double pass methods up to 180.61 MPa. Moreover, DSP showed better tensile test and hardness test compared to NDP method. The optimum parameters were found to be single pass method with 1200 rpm of rotational speed. Therefore economically sound to only perform SP method to obtain maximum tensile strength for AA6061 FSW with thickness of 6 mm.

  18. Weld Nugget Temperature Control in Thermal Stir Welding

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2014-01-01

    A control system for a thermal stir welding system is provided. The control system includes a sensor and a controller. The sensor is coupled to the welding system's containment plate assembly and generates signals indicative of temperature of a region adjacent and parallel to the welding system's stir rod. The controller is coupled to the sensor and generates at least one control signal using the sensor signals indicative of temperature. The controller is also coupled to the welding system such that at least one of rotational speed of the stir rod, heat supplied by the welding system's induction heater, and feed speed of the welding system's weld material feeder are controlled based on the control signal(s).

  19. Weld pool image sensor for pulsed MIG welding

    Institute of Scientific and Technical Information of China (English)

    Liu Pengfei; Sun Zhenguo; Huang Cao; Chen Qiang

    2008-01-01

    Visual image sensor is developed to detect the weld pool images in pulsed MIG welding. An exposure controller, which is composed of the modules of the voltage transforming, the exposure parameters presetting, the complex programmable logic device (CPLD) based logic controlling, exposure signal processing, the arc state detecting, the mechanical iris driving and so on, is designed at first. Then, a visual image sensor consists of an ordinary CCD camera, optical system and exposure controller is established. The exposure synchronic control logic is described with very-high-speed integrated circuit hardware description language (VHDL) and programmed with CPLD, to detect weld pool images at the stage of base current in pulsed MIG welding. Finally, both bead on plate welding and V groove filled welding are carried out, clear and consistent weld pool images are acquired.

  20. Procedure for Computing Residual Stresses from Neutron Diffraction Data and its Application to Multi-Pass Dissimilar Weld

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei [ORNL; Feng, Zhili [ORNL; Crooker, Paul [Electric Power Research Institute (EPRI)

    2011-01-01

    Neutron diffraction is a powerful tool for non-destructive measurement of internal residual stresses of welded structures. The conventional approach for determination of residual stresses requires the knowledge of stress-free lattice spacing a priori. For multiple-pass dissimilar metal welds common to nuclear reactor pipeline systems, the stress-free lattice parameter is a complex function of position due to the chemistry inhomogeneity in the weld region and can be challenging to determine experimentally. This paper presents a new approach to calculate the residual stress field in dissimilar welds without the use of stress-free lattice parameter. The theoretical basis takes advantage of the fact that the normal component of welding residual stresses is typically small for thin plate or pipe welds. The applicability of the new approach is examined and justified in a multi-pass dissimilar metal weld consisting of a stainless steel plate and a nickel alloy filler metal. The level of uncertainties associated with this new approach is assessed. Neutron diffraction experiment is carried out to measure the lattice spacing at various locations in the dissimilar weld. A comb-shaped specimen, electro-discharge machined from a companion weld, is used to determine the stress-free lattice spacing. The calculated results from the new approach are consistent with those from the conventional approach. The new approach is found to be a practical method for determining the two in-plane residual stress components in thin plate or pipe dissimilar metal welds.

  1. Investigation of residual stresses in welded joints of heat-resistant magnesium alloy ML10 after electrodynamic treatment

    Directory of Open Access Journals (Sweden)

    L.M. Lobanov

    2016-06-01

    Full Text Available In repair of aircraft structures of magnesium alloy ML10, the argon arc non-consumable electrode welding is used. In this case, the residual welding stresses occur in repair welds, being one of the causes for reducing the service characteristics of the restored products. Residual stresses arise as a result of welding. Post-weld heat treatment is used to reduce the residual stresses. The heat treatment, which occurs after welding, increases the cost of repair. This leads to the search for alternative methods to control the stressed state of welded joints, one of which is electrodynamic treatment, which reduces the level of residual stresses in repair welds, and as a consequence, the cost of the welding repair in restoring aircraft structures. It was found from the results of experiments carried out, that the electrodynamic treatment allows reduces the initial level of stresses in welded joints, reaching 120 MPa, to 30 MPa, and at definite geometric characteristics of the specimens forming the field of compressive stresses, the values of which are equal to –50 MPa. It is shown that the optimum distance between the zones of treatment, being 5 mm, provides the guaranteed covering the zones of electrodynamic effect and, as a consequence, the maximum efficiency of the electric dynamic treatment.

  2. Type specimen studies in Pleurotus

    NARCIS (Netherlands)

    Petersen, Ronald H.; Krisai-Greilhuber, Irmgard

    1999-01-01

    An epitype specimen is designated for Pleurotus cornucopiae. Morphological examination of Mexican material and the type specimen of P. opuntiae showed that the distribution of this species includes North Africa and the highlands of Mexico. The type specimen of Lentinus (Pleurotus) eugrammus reveals

  3. Spot Welding of Honeycomb Structures

    Science.gov (United States)

    Cohal, V.

    2017-08-01

    Honeycomb structures are used to prepare meals water jet cutting machines for textile. These honeycomb structures are made of stainless steel sheet thickness of 0.1-0.2 mm. Corrugated sheet metal strips are between two gears with special tooth profile. Hexagonal cells for obtaining these strips are welded points between them. Spot welding device is three electrodes in the upper part, which carries three welding points across the width of the strip of corrugated sheet metal. Spot welding device filled with press and advance mechanisms. The paper presents the values of the regime for spot welding.

  4. Hybrid laser-arc welding

    DEFF Research Database (Denmark)

    the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

  5. Numerical simulation of welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær; Thorborg, Jesper

    Aim of project:To analyse and model the transient thermal field from arc welding (SMAW, V-shaped buttweld in 15mm plate) and to some extend the mechanical response due to the thermal field. - To implement this model in a general purpose finite element program such as ABAQUS.The simulation...... stress is also taken into account.Work carried out:With few means it is possible to define a thermal model which describes the thermal field from the welding process in reasonable agreement with reality. Identical results are found with ABAQUS and Rosenthal’s analytical solution of the governing heat...... transfer equation under same conditions. It is relative easy tointroduce boundary conditions such as convection and radiation where not surprisingly the radiation has the greatest influence especially from the high temperature regions in the weld pool and the heat affected zone.Due to the large temperature...

  6. Milestones in welding technology

    Science.gov (United States)

    Dolby, Richard E.

    2013-09-01

    Sir Alan's PhD thesis describes his research into cracking during arc welding of armour steels. Throughout his career, he had a strong interest in defects of all types, how they formed in metallic structures and how the larger ones could be detected and sized by non-destructive techniques. He was also vitally concerned with how defects impacted on the engineering integrity of welded structures, particularly the risk of fracture in nuclear plant. This study presents a view of some of the major milestones in global welding technology that took place over the 60 or more years of Sir Alan's career and highlights those where he had a personal and direct involvement.

  7. Development of automated welding processes for field fabrication of thick-walled pressure vessels: electron beam method. Eighth quarterly report, 1 July-30 September 1979. [8-inch SA387 Grade 22 Class 2 (2 1/4 Cr-1Mo)

    Energy Technology Data Exchange (ETDEWEB)

    Weber, C.M.

    1979-01-01

    Objective is to develop and demonstrate an electron beam welding procedure for welding 8-inch thick SA 387 Grade 22 Class (2-1/4 Cr-1 Mo) steel. A total of 469 experimental welds have been made to date. Efforts to develop welding procedures which produce defect-free welds have been successfully completed. Techniques for acceptably starting and stopping electron beam welds were developed. Work on developing an EB repair technique is in progress. It has been learned that re-welding of holes, without metal additions, is unacceptable. Work to define the joint fit-up requirements is nearly complete. A considerable amount of joint mismatch can be readily welded and a joint gap opening in excess of 0.100 inch can be welded without alteration of the welding procedure. Another large test plate was welded using equipment with a modified drive. The weld was unacceptable due to porosity. It appears that poor base metal quality is adversely affecting weld quality. Specimens for testing the as-welded mechanical properties have been machined and are being tested.

  8. Recent Corrosion Research Trends in Weld Joints

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hwan Tae; Kil, Sang Cheol [Korea Institute of Science and Technology Information, Seoul (Korea, Republic of); Hwang, Woon Suk [Inha University, Incheon (Korea, Republic of)

    2007-04-15

    The increasing interest in the corrosion properties of weld joints in the corrosive environment is placing stringent demands on the manufacturing techniques and performance requirements, and the manufacture employs the high quality and efficiency welding process to produce welds. Welding plays an important role in the fabrication of chemical plants, nuclear power plant, ship construction, and this has led to an increasing attention to the corrosion resistant weld joints. This paper covers recent technical trends of welding technologies for corrosion resistance properties including the COMPENDEX DB analysis of welding materials, welding process, and welding fabrications

  9. Effects of welding wire composition and welding process on the weld metal toughness of submerged arc welded pipeline steel

    Institute of Scientific and Technical Information of China (English)

    De-liang Ren; Fu-ren Xiao; Peng Tian; Xu Wang; Bo Liao

    2009-01-01

    The effects of alloying elements in welding wires and submerged arc welding process on the microstructures and low-temperature impact toughness of weld metals have been investigated.The results indicate that the optimal contents of alloying elements in welding wires can improve the low-temperature impact toughness of weld metals because the proentectoid ferrite and bainite formations can be suppressed,and the fraction of acicular ferrite increases.However,the contents of alloying elements need to vary along with the welding heat input.With the increase in welding heat input,the contents of alloying elements in welding wires need to be increased accordingly.The microstructures mainly consisting of acicular ferrite can be obtained in weld metals after four-wire submerged arc welding using the wires with a low carbon content and appropriate contents of Mn,Mo,Ti-B,Cu,Ni,and RE,resulting in the high low-temperature impact toughness of weld metals.

  10. Friction Stir Welding of Al 5052 with Al 6061 Alloys

    Directory of Open Access Journals (Sweden)

    N. T. Kumbhar

    2012-01-01

    Full Text Available Friction stir welding (FSW, a solid-state joining technique, is being extensively used in similar as well as dissimilar joining of Al, Mg, Cu, Ti, and their alloys. In the present study, friction stir welding of two aluminium alloys—AA6061 and AA5052—was carried out at various combinations of tool rotation speeds and tool traverse speeds. The transverse cross-section of the weld was used for optical as well as electron microscopy observations. The microstructural studies were used to get an indication of the extent of material mixing both at the macro- and microscales. It was observed that, at the interface region, both materials exhibited similar texture despite the nonrigorous mixing of the materials in the nugget. The extent of interdiffusion of alloying elements at the interface was studied using electron probe microanalysis. The tensile testing evaluation of these specimens showed good mechanical properties. The interdiffusion of alloying elements and development of similar orientations in the nugget could have contributed to the better tensile properties of the friction-stir-welded AA5052-AA6061 specimens.

  11. Effects of argon gas flow rate on laser-welding.

    Science.gov (United States)

    Takayama, Yasuko; Nomoto, Rie; Nakajima, Hiroyuki; Ohkubo, Chikahiro

    2012-01-01

    The purpose of this study was to evaluate the effects of the rate of argon gas flow on joint strength in the laser-welding of cast metal plates and to measure the porosity. Two cast plates (Ti and Co-Cr alloy) of the same metal were abutted and welded together. The rates of argon gas flow were 0, 5 and 10 L/min for the Co-Cr alloy, and 5 and 10 L/min for the Ti. There was a significant difference in the ratio of porosity according to the rate of argon gas flow in the welded area. Argon shielding had no significant effect on the tensile strength of Co-Cr alloy. The 5 L/min specimens showed greater tensile strength than the 10 L/min specimens for Ti. Laser welding of the Co-Cr alloy was influenced very little by argon shielding. When the rate of argon gas flow was high, joint strength decreased for Ti.

  12. Weld penetration and defect control

    Energy Technology Data Exchange (ETDEWEB)

    Chin, B.A.

    1992-05-15

    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.

  13. Friction welding of a nickel free high nitrogen steel: influence of forge force on microstructure, mechanical properties and pitting corrosion resistance

    Directory of Open Access Journals (Sweden)

    Mrityunjoy Hazra

    2014-01-01

    Full Text Available In the present work, nickel free high nitrogen austenitic stainless steel specimens were joined by continuous drive friction welding process by varying the amount of forge (upsetting force and keeping other friction welding parameters such as friction force, burn-off, upset time and speed of rotation as constant at appropriate levels. The joint characterization studies include microstructural examination and evaluation of mechanical (micro-hardness, impact toughness and tensile and pitting corrosion behaviour. The integrity of the joint, as determined by the optical microscopy was very high and no crack and area of incomplete bonding were observed. Welds exhibited poor Charpy impact toughness than the parent material. Toughness for friction weld specimens decreased with increase in forge force. The tensile properties of all the welds were almost the same (irrespective of the value of the applied forge force and inferior to those of the parent material. The joints failed in the weld region for all the weld specimens. Weldments exhibited lower pitting corrosion resistance than the parent material and the corrosion resistance of the weld specimens was found to decrease with increase in forge force.

  14. An Investigation on the Influence of Root Defects on the Fatigue Life of the Welded Structure of a Large Two-Stroke Diesel Engine

    DEFF Research Database (Denmark)

    Hansen, Anders V.; Olesen, John Forbes; Agerskov, Henning

    2004-01-01

    -models of the welded joints, are described and the results presented. In addition, large-scale test specimens with controlled lack-of-fusion weld root geometry were manufactured and fatigue tested to develop S-N curves and determine threshold stress intensity factor range values. These were established for opening...

  15. Stress corrosion crack initiation of alloy 182 weld metal in primary coolant - Influence of chemical composition

    Energy Technology Data Exchange (ETDEWEB)

    Calonne, O.; Foucault, M.; Steltzlen, F. [AREVA (France); Amzallag, C. [EDF SEPTEN (France)

    2011-07-01

    Nickel-base alloys 182 and 82 have been used extensively for dissimilar metal welds. Typical applications are the J-groove welds of alloy 600 vessel head penetrations, pressurizer penetrations, heater sleeves and bottom mounted instrumented nozzles as well as some safe end butt welds. While the overall performance of these weld metals has been good, during the last decade, an increasing number of cases of stress corrosion cracking of Alloy 182 weld metal have been reported in PWRs. In this context, the role of weld defects has to be examined. Their contribution in the crack initiation mechanism requires laboratory investigations with small scale characterizations. In this study, the influence of both alloy composition and weld defects on PWSCC (Stress Corrosion Cracking in Primary Water) initiation was investigated using U-bend specimens in simulated primary water at 320 C. The main results are the following: -) the chemical compositions of the weld deposits leading to a large propensity to hot cracking are not the most susceptible to PWSCC initiation, -) macroscopically, superficial defects did not evolve during successive exposures. They can be included in large corrosion cracks but their role as 'precursors' is not yet established. (authors)

  16. Subtask 12B2: Development of laser welding techniques for vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Strain, R.V.; Leong, K.H.; Keppler, E.E.; Smith, D.L. [Argonne National Laboratory, IL (United States)

    1995-03-01

    The development of techniques for joining vanadium alloys will be required for the construction of fusion devices utilizing the desirable properties of these alloys. The primary objective of this program is to develop of laser welding techniques for vanadium alloys, particularly for the manufacture of welded materials testing specimens. Laser welding is potentially advantageous because of its flexibility and the reduced amount of material effected by the weld. Lasers do not require a vacuum (as does electron beam welders) and the welds they produce have large depth-to-width ratios. Results of scoping tests using a small, pulsed laser (50 joule, YAG laser) indicated that lasers could produce successful welds in vanadium alloy (V-5%Cr-5%Ti) sheet (1-mm thick) when the fusion zone was isolated from air. The pulsed laser required an isolating chamber filled with inert gas to produce welds that did not contain cracks and showed only minor hardness increases. Successful bead-on-plate welds have been made to depths of about 4-mm using a 6 kW continuous CO{sub 2} laser with argon purging. 2 figs.

  17. Laser welding study for further development in essential power plant part repairs

    Directory of Open Access Journals (Sweden)

    Isarawit Chaopanich

    2015-06-01

    Full Text Available The objective of this research work was to study the effects of laser welding when compared with shield metal arc welding (SMAW process on the heat input, welded deposit rate, residual stress, distortion, microstructure and micro hardness. The martensitic stainless steel grade 431 specimens were overlay welded with the stainless steel filler metals. From the results, the heat input of 0.26 kJ/mm in laser welding calculated was significantly lower than that of 1.66 kJ/mm in SMAW, and contributed to low level residual stress, minimal distortion, very small penetration depth and heat affected zone (HAZ of less than 100 µm. The micro hardness results indicated that the maximum value from laser welding in the HAZ was 370.2 HV lower than the value from SMAW of 525.5 HV. The welded deposit rate for laser welding was with 26.5 mm3 /min remarkably lower than the rate for SMAW of 1,800 mm3 /min.

  18. Residual stress analysis of aluminium welds with high energy synchrotron radiation at the HARWI II beamline

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Torben; Martins, Rene V.; Schreyer, Andreas [GKSS Research Centre, Geesthacht (Germany)

    2008-07-01

    In civil aircraft production advanced welding techniques, like laser beam welding or friction stir welding, are used to reduce weight and production costs. By the welding process residual stresses are introduced in the weld zone and the surrounding area. These stresses may depend on diverse factors and can have disadvantageous influence on the service performance of the weld. For strain scanning GKSS research centre built up the high energy materials science beamline HARWI II at HASYLAB. The use of high energetic photons from about 80 keV-120 keV enables diffraction experiments in transmission geometry, which provides the information about the macroscopic stresses. A large sample-detector-distance ensures a high angular resolution for the peak position determination. The heavy load diffractometer allows making use of massive sample environments. For example laser beam welded t- and butt-joints were investigated with high spatial resolution. The large grain size of the specimen makes the measurements with high spatial resolution more difficult due to the poor grain statistics. The influences of the gauge volume size and grain statistics on the strain measurements were systematically investigated. For the t-joint configuration two dimensional stress maps were calculated from the data. For the near future an in-situ FSW experiment is planed to investigate the metallophysical processes during the welding.

  19. Fracture strength of different soldered and welded orthodontic joining configurations with and without filling material.

    Science.gov (United States)

    Bock, Jens Johannes; Bailly, Jacqueline; Gernhardt, Christian Ralf; Fuhrmann, Robert Andreas Werner

    2008-01-01

    The aim of this study was to compare the mechanical strength of different joints made by conventional brazing, TIG and laser welding with and without filling material. Five standardized joining configurations of orthodontic wire in spring hard quality were used: round, cross, 3 mm length, 9 mm length and 7 mm to orthodontic band. The joints were made by five different methods: brazing, tungsten inert gas (TIG) and laser welding with and without filling material. For the original orthodontic wire and for each kind of joint configuration or connecting method 10 specimens were carefully produced, totalizing 240. The fracture strengths were measured with a universal testing machine (Zwick 005). Data were analyzed by ANOVA (p=0.05) and Bonferroni post hoc test (p=0.05). In all cases, brazing joints were ruptured on a low level of fracture strength (186-407 N). Significant differences between brazing and TIG or laser welding (pfracture strength means were observed for laser welding with filling material and 3 mm joint length (998 N). Using filling materials, there was a clear tendency to higher mean values of fracture strength in TIG and laser welding. However, statistically significant differences were found only in the 9-mm long joints (pfracture strength of welded joints was positively influenced by the additional use of filling material. TIG welding was comparable to laser welding except for the impossibility of joining orthodontic wire with orthodontic band.

  20. Quantitative metal magnetic memory reliability modeling for welded joints

    Science.gov (United States)

    Xing, Haiyan; Dang, Yongbin; Wang, Ben; Leng, Jiancheng

    2016-03-01

    Metal magnetic memory(MMM) testing has been widely used to detect welded joints. However, load levels, environmental magnetic field, and measurement noises make the MMM data dispersive and bring difficulty to quantitative evaluation. In order to promote the development of quantitative MMM reliability assessment, a new MMM model is presented for welded joints. Steel Q235 welded specimens are tested along the longitudinal and horizontal lines by TSC-2M-8 instrument in the tensile fatigue experiments. The X-ray testing is carried out synchronously to verify the MMM results. It is found that MMM testing can detect the hidden crack earlier than X-ray testing. Moreover, the MMM gradient vector sum K vs is sensitive to the damage degree, especially at early and hidden damage stages. Considering the dispersion of MMM data, the K vs statistical law is investigated, which shows that K vs obeys Gaussian distribution. So K vs is the suitable MMM parameter to establish reliability model of welded joints. At last, the original quantitative MMM reliability model is first presented based on the improved stress strength interference theory. It is shown that the reliability degree R gradually decreases with the decreasing of the residual life ratio T, and the maximal error between prediction reliability degree R 1 and verification reliability degree R 2 is 9.15%. This presented method provides a novel tool of reliability testing and evaluating in practical engineering for welded joints.

  1. Integrated sensors for robotic laser welding

    NARCIS (Netherlands)

    Iakovou, D.; Aarts, Ronald G.K.M.; Meijer, J.; Beyer, E.; Dausinger, F; Ostendorf, A; Otto, A.

    2005-01-01

    A welding head is under development with integrated sensory systems for robotic laser welding applications. Robotic laser welding requires sensory systems that are capable to accurately guide the welding head over a seam in three-dimensional space and provide information about the welding process as

  2. Infrared-Controlled Welding of Solar Cells

    Science.gov (United States)

    Paulson, R.; Finnell, S. E.; Decker, H. J.; Hodor, J. R.

    1982-01-01

    Proposed apparatus for welding large arrays of solar cells to flexible circuit substrates would sense infrared emission from welding spot. Emission would provide feedback for control of welding heat. Welding platform containing optical fibers moves upward through slots in movable holding fixture to contact solar cells. Fibers pick up infrared radiation from weld area.

  3. Sensor integration for robotic laser welding processes

    NARCIS (Netherlands)

    Iakovou, Dimitrios; Aarts, Ronald; Meijer, Johan

    2005-01-01

    The use of robotic laser welding is increasing among industrial applications, because of its ability to weld objects in three dimensions. Robotic laser welding involves three sub-processes: seam detection and tracking, welding process control, and weld seam inspection. Usually, for each sub-process,

  4. A study on welded joint toughness of X-60 steel

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Charpy impact test and COD test were performed on the specimens subjected to simulated welded thermal cycle and the specimens taken from welded joint. The optical microscope, TEM, SEM, EDAX and XRD analysis have been used to investigate the behaviors of second phase particles and the effects of microstructure on toughness separately. The results are as follows. The dispersed second phase particles can effectively retard the growth of austenite grain in the coarse-grained HAZ (CGHAZ), and improve the toughness. When t8/5 is different, the behaviors of the particles are also different in dissolving, coarsening and re-precipitating. The ability of retarding the growth of austenite grain will be affected. When t8/5 increases from 10 s to 70 s, the microstructure of CGHAZ will transform from upper bainite and granular bainite to granular bainite, and the size of austenite grain will grow a little, thus the toughness of the materials decreases slightly.

  5. Repair welding process of friction stir welding groove defect

    Institute of Scientific and Technical Information of China (English)

    LIU Hui-jie; ZHANG Hui-jie

    2009-01-01

    The groove defect formed in the friction stir welding dramatically deteriorates weld appearances and mechanical properties of the joints owing to its larger size and penetration. Therefore, the friction stir repair welding was utilized to remove such a groove defect, and the focus was placed on the mechanical properties and microstructural characteristics of the repair joints so as to obtain an optimum repair welding process. The experimental results indicate that the groove defect can be removed by friction stir repair welding, and the offset repair welding process is superior to the symmetrical repair welding process. In the symmetrical repair welding process, a large number of fine cavity defects and an obvious aggregation of hard-brittle phase Al2Cu occur, accordingly the mechanical properties of the repair joint are weakened, and the fracture feature of repair joint is partially brittle and partially plastic. A good-quality repair joint can be obtained by the offset repair welding process, and the repair joint is fractured near the interface between the weld nugget zone and thermal-mechanically affected zone.

  6. Deconvoluting the Friction Stir Weld Process for Optimizing Welds

    Science.gov (United States)

    Schneider, Judy; Nunes, Arthur C.

    2008-01-01

    In the friction stir welding process, the rotating surfaces of the pin and shoulder contact the weld metal and force a rotational flow within the weld metal. Heat, generated by the metal deformation as well as frictional slippage with the contact surface, softens the metal and makes it easier to deform. As in any thermo-mechanical processing of metal, the flow conditions are critical to the quality of the weld. For example, extrusion of metal from under the shoulder of an excessively hot weld may relax local pressure and result in wormhole defects. The trace of the weld joint in the wake of the weld may vary geometrically depending upon the flow streamlines around the tool with some geometry more vulnerable to loss of strength from joint contamination than others. The material flow path around the tool cannot be seen in real time during the weld. By using analytical "tools" based upon the principles of mathematics and physics, a weld model can be created to compute features that can be observed. By comparing the computed observations with actual data, the weld model can be validated or adjusted to get better agreement. Inputs to the model to predict weld structures and properties include: hot working properties ofthe metal, pin tool geometry, travel rate, rotation and plunge force. Since metals record their prior hot working history, the hot working conditions imparted during FSW can be quantified by interpreting the final microstructure. Variations in texture and grain size result from variations in the strain accommodated at a given strain rate and temperature. Microstructural data from a variety of FSWs has been correlated with prior marker studies to contribute to our understanding of the FSW process. Once this stage is reached, the weld modeling process can save significant development costs by reducing costly trial-and-error approaches to obtaining quality welds.

  7. Effect of weld microstructure on weld properties in A-TIG welding of titanium alloy

    Institute of Scientific and Technical Information of China (English)

    刘凤尧; 杨春利; 林三宝; 吴林; 苏生

    2003-01-01

    Conventional TIG welding is known as its low productivity and limited weld depth in a single pass. Activating TIG welding (A-TIG) can greatly improve the penetration when compared with the conventional TIG welding. The effects of five kinds of activating fluxes with single component (NaF, CaF2, AlF3, NaCl or CaCl2) on penetration, microstructure and weld mechanical properties during the TIG welding of titanium alloy Ti-6Al-4V were studied. Compared with the conventional TIG welding, the experimental results show that the fluxes can greatly improve the penetration at the same welding specifications. This is because of the constriction of anode spots and the change of surface tension grads. Among them the effect of flux NaF is the best in the weld tensile strength, and the effect of flux CaF2 on the weld bend intension is the best. The appearance of inferior crystal grains and the structure of trident crystal grains are the main reasons that the performance of weld with fluoride is improved. These experimental results can be used as an aid for selecting suitable activating flux for titanium alloy.

  8. Development of Temper Bead Welding Process for Weld Overlay of Dissimilar Welds

    Energy Technology Data Exchange (ETDEWEB)

    Byeon, J. G.; Park, K. S.; Kim, Y. J. [Doosan Heavy Industries and Construction Co., Ltd., Seoul (Korea, Republic of)

    2008-10-15

    In recent years, the dissimilar weld metal used to connect stainless steel piping and low alloy steel or carbon steel components have experienced cracking in nuclear reactor piping systems. The cracking has been observed in several Pressurized Water Reactors in overseas. In Several cases, the cracking was repaired using structural weld overlays, a repair technique that has been in use in the U.S. in Boiling Water Reactors for over twenty years. Although weld overlays have been used primarily as a repair for flawed piping, they can also be applied at locations that have not yet exhibited any cracking, but are considered susceptible to cracking. The purpose of this research is to develop the temper bead weld process for the weld overlay of the dissimilar weld pipe. We developed equipment for the overlay system, applied Procedure Qualification(PQ) for the temper bead welding process.

  9. Standard Guide for Reconstitution of Irradiated Charpy-Sized Specimens

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This guide covers procedures for the reconstitution of ferritic pressure boundary steels used in nuclear power plant applications, Type A Charpy (Test Methods E 23) specimens and specimens suitable for testing in three point bending in accordance with Test Methods E 1921 or E 1820. Materials from irradiation programs (principally broken specimens) are reconstituted by welding end tabs of similar material onto remachined specimen sections that were unaffected by the initial test. Guidelines are given for the selection of suitable specimen halves and end tab materials, for dimensional control, and for avoidance of overheating the notch area. A comprehensive overview of the reconstitution methodologies can be found in Ref (1). 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard...

  10. Effect of Welding Parameters on Microstructure, Thermal, and Mechanical Properties of Friction-Stir Welded Joints of AA7075-T6 Aluminum Alloy

    Science.gov (United States)

    Lotfi, Amir Hossein; Nourouzi, Salman

    2014-06-01

    A high-strength Al-Zn-Mg-Cu alloy AA7075-T6 was friction-stir welded with various process parameter combinations incorporating the design of the experiment to investigate the effect of welding parameters on the microstructure and mechanical properties. A three-factors, five-level central composition design (CCD) has been used to minimize the number of experimental conditions. The friction-stir welding parameters have significant influence on the heat input and temperature profile, which in turn regulates the microstructural and mechanical properties of the joints. The weld thermal cycles and transverse distribution of microhardness of the weld joints were measured, and the tensile properties were tested. The fracture surfaces of tensile specimens were observed by a scanning electron microscope (SEM), and the formation of friction-stir processing zone has been analyzed macroscopically. Also, an equation was derived to predict the final microhardness and tensile properties of the joints, and statistical tools are used to develop the relationships. The results show that the peak temperature during welding of all the joints was up to 713 K (440 °C), which indicates the key role of the tool shoulder diameter in deciding the maximum temperature. From this investigation, it was found that the joint fabricated at a rotational speed of 1050 rpm, welding speed of 100 mm/min, and shoulder diameter of 14 mm exhibited higher mechanical properties compared to the other fabricated joints.

  11. Fracture toughness master curve characterization of Linde 1092 weld metal for Beaver valley 1 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bong Sang; Yang, Won Jon; Hong, Jun Hwa

    2000-12-01

    This report summarizes the test results obtained from the Korean contribution to the integrity assessment of low toughness Beaver Valley reactor vessel by characterizing the fracture toughness of Linde 1092 (No. 305414) weld metal. 10 PCVN specimens and 10 1T-CT specimens were tested in accordance with the ASTM E 1921-97 standard, 'Standard test method for determination of reference temperature, T{sub o}, for ferritic steels in the transition range'. This results can also be useful for assessment of Linde 80 low toughness welds of Kori-1.

  12. Effects of post-weld heat treatment on dissimilar metal joint between aluminum alloy and stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Dong Honggang, E-mail: donghg@dlut.edu.cn [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116085 (China); Liao Chuanqing; Yang Liqun [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116085 (China); Dong Chuang [Key Lab of Materials Modification, Dalian University of Technology, Ministry of Education, Dalian 116085 (China)

    2012-07-30

    Highlights: Black-Right-Pointing-Pointer Al alloy was joined to stainless steel with Zn-15Al flux-cored filler wire. Black-Right-Pointing-Pointer Effects of post-weld heat treatment on joint performance were investigated. Black-Right-Pointing-Pointer The distribution of Zn-rich phases in the weld changed with PWHT conditions. Black-Right-Pointing-Pointer Fine Zn-rich phases uniformly distributed in the weld enhanced the joint strength. Black-Right-Pointing-Pointer Fractured surfaces of the specimens after tensile testing were examined. - Abstract: Lap joining of 5A02 aluminum alloy to 304 stainless steel sheets was conducted by gas tungsten arc welding with Zn-15%Al flux-cored filler wire, and the effects of the temperature and duration time during post-weld heat treatment on the microstructure and mechanical properties of the resultant joints were investigated. The experimental results show that the concentration and size of the Zn-rich phases in the weld, especially along the weld/steel interface, changed with different temperature and duration time, and consequently affected the joint strength. The fine Zn-rich phases uniformly distributed in the weld could enhance the joint strength; however, the coarse Zn-rich phases along the interfacial layer would degrade the bonding strength of the interfacial layer. The fractured surfaces of the specimens after tensile testing were also examined.

  13. Influence of pin geometry on mechanical and structural properties of butt friction stir welded 2024-T351 aluminum alloy

    Directory of Open Access Journals (Sweden)

    Radisavljević Igor Z.

    2015-01-01

    Full Text Available The aim of this work was to investigate the combined effect of small difference in pin geometry, together with rotation and welding speed on the weldability, mechanical and structural properties of FSW 2024-T351 Al plates. The only difference in tool pin design was the shape of thread: regular and rounded. Specimens were welded using rotation rate of 750 rev/min and welding speeds of 73 and 93 mm/min. In all four cases, specimens were defect free, with good or acceptable weld surface. Modification in pin design showed strong influence on macro structure and hardness distribution. Weak places are identified as low hardness zone, close to the nugget zone and are in good agreement with fracture location in tensile testing. Weld efficiency, as a measure of weld quality, are better in case of 310 tool, while UTS values can differ up to 13% for the equal welding parameters. Therefore, it can be assumed that small modification in tool design, particularly in pin geometry, can have great influence on weld formation and mechanical properties.

  14. 46 CFR 57.04-1 - Test specimen requirements and definition of ranges (modifies QW 202, QW 210, QW 451, and QB 202).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Test specimen requirements and definition of ranges (modifies QW 202, QW 210, QW 451, and QB 202). 57.04-1 Section 57.04-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING WELDING AND BRAZING Procedure Qualification Range § 57.04-1 Test specimen requirements...

  15. Thermal Stresses in Welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær

    1998-01-01

    Studies of the transient temperature fields and the hereby induced deformations and stressses in a butt-welded mild steel plate modelledrespectively in 2D plane stress state (as well as plane strain state) and in full 3D have been done. The model has been implemented in the generalpurpose FE...

  16. Welding. Student Learning Guide.

    Science.gov (United States)

    Palm Beach County Board of Public Instruction, West Palm Beach, FL.

    This student learning guide contains 30 modules for completing a course in welding. It is designed especially for use in secondary schools in Palm Beach County, Florida. Each module covers one task, and consists of a purpose, performance objective, enabling objectives, learning activities keyed to resources, information sheets, student self-check…

  17. SHADOW: a new welding technique

    Science.gov (United States)

    Kramer, Thorsten; Olowinsky, Alexander M.; Durand, Friedrich

    2002-06-01

    The new welding technique 'SHADOW ' is introduced. SHADOW means the use of a single pulse to generate a quasi continuous weld of several millimeters in length. HET processing time is defined by the pulse duration of the pulsed laser. At present, a state-of-the-art laser is capable of a maximum pulse duration of 20 ms. The variation of the laser power depend on time is a vital capability of the pulsed laser to adapt the energy deposition into the workpiece. Laser beam welds of several watch components were successfully performed. Similar metals like crowns and axes made out of stainless steel have been welded using pulsed laser radiation. Applying a series of about 130 single pulses for the crown-axis combination the total energy accumulates to 19.5 J. The use of the SHADOW welding technique reduces the energy to 2.5 J. While welding dissimilar metals like stainless steel and bras, the SHADOW welding reduces drastically the contamination as well as the distortion. Laser beam welding of copper has a low process reliability due to the high reflection and the high thermal conductivity. SHADOW welds of 3.6 mm length were performed on 250 micrometers thick copper plates with very high reproducibility. As a result, a pilot plant for laser beam welding of copper plates has been set up. The work to be presented has partly been funded by the European Commission in a project under the contract BRPR-CT-0634.

  18. Welding, Bonding and Fastening, 1984

    Science.gov (United States)

    Buckley, J. D. (Editor); Stein, B. A. (Editor)

    1985-01-01

    A compilation of papers presented in a joint NASA, American Society for Metals, The George Washington University, American Welding Soceity, and Society of Manufacturing Engineers conference on Welding, Bonding, and Fastening at Langley Research Center, Hampton, VA, on October 23 to 25, 1984 is given. Papers were presented on technology developed in current research programs relevant to welding, bonding, and fastening of structural materials required in fabricating structures and mechanical systems used in the aerospace, hydrospace, and automotive industries. Topics covered in the conference included equipment, hardware and materials used when welding, brazing, and soldering, mechanical fastening, explosive welding, use of unique selected joining techniques, adhesives bonding, and nondestructive evaluation. A concept of the factory of the future was presented, followed by advanced welding techniques, automated equipment for welding, welding in a cryogenic atmosphere, blind fastening, stress corrosion resistant fasteners, fastening equipment, explosive welding of different configurations and materials, solid-state bonding, electron beam welding, new adhesives, effects of cryogenics on adhesives, and new techniques and equipment for adhesive bonding.

  19. Small-scale explosive welding of aluminum

    Science.gov (United States)

    Bement, L. J.

    1972-01-01

    Welding technique uses very small quantities of explosive ribbon to accomplish small-scale lap-welding of aluminum plates. Technique can perform small controlled welding with no length limitations and requires minimal protective shielding.

  20. Comparison of Welding Residual Stresses of Hybrid Laser-Arc Welding and Submerged Arc Welding in Offshore Steel Structures

    DEFF Research Database (Denmark)

    Andreassen, Michael Joachim; Yu, Zhenzhen; Liu, Stephen

    2016-01-01

    induced residual stresses. It is also investigated whether the assumption of residual stresses up to yield strength magnitude are present in welded structures as stated in the design guidelines. The fatigue strength for welded joints is based on this assumption. The two welding methods investigated...... are hybrid laser-arc welding (HLAW) and submerged arc welding (SAW). Both welding methods are applied for a full penetration butt-weld of 10 mm thick plates made of thermomechanically hot-rolled, low-carbon, fine-grain S355ML grade steel used in offshore steel structures. The welding residual stress state...

  1. Ti–6Al–4V welded joints via electron beam welding: Microstructure, fatigue properties, and fracture behavior

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaoguang [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China); Co-Innovation Center for Advanced Aero-Engine, Beijing 100191 (China); Li, Shaolin [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China); Qi, Hongyu, E-mail: qhy@buaa.edu.cn [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China); Co-Innovation Center for Advanced Aero-Engine, Beijing 100191 (China)

    2014-03-01

    The effect of microstructural characteristics on the fatigue properties of electron beam-welded joints of forged Ti–6Al–4V and its fracture behavior were investigated. Tensile tests and fatigue tests were conducted at room temperature in air atmosphere. The test data were analyzed in relation to microstructure, high-cycle fatigue properties, low-cycle fatigue properties, and fatigue crack propagation properties. The high-cycle fatigue test results indicated that the fatigue strength of the joint welded via electron beam welding was higher than that of the base metal because the former had a high yield strength and all high-cycle fatigue specimens were fractured in the base metal. Although the joint specimens had a lower low-cycle fatigue life than the base metal, they mainly ruptured at the fusion zone of the joint specimen and their crack initiation mechanism is load-dependent. The fatigue crack propagation test results show that the joint had a slower crack propagation rate than the base metal, which can be attributed to the larger grain in the fusion zone.

  2. Distribution of mechanical properties in Alloy 82/182 dissimilar weld joint between SA508 Gr.3 nozzle and F316L safe-end

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Weon [Chosun Univ., Gwangju (Korea, Republic of)

    2009-07-01

    This paper presents the distribution of tensile properties and fracture toughness in Alloy 82/182 dissimilar weld joint between SA508 Gr.3 nozzle and F316L SS safe-end at ambient temperature. Tensile and J-R tests were conducted using the specimens extracted form both base metals, Heat Affected Zones (HAZs), buttering, and various regions of weld metal. It showed that root region of weld exhibits higher strengths than upper region. The yield and tensile strengths considerably varied within root region of weld, the lowest strengths appeared at buttering region and gradually increased with approaching boundary with F316L stainless steel, whereas the variation of strengths within the weld was insignificant at upper region of weld. It was also indicated that fracture toughness of Alloy 82/182 weld metal was lower than that of both base metals and both HAZs. Within the Alloy 82/182 weld, the center of weld showed slightly lower fracture toughness than weld boundary and buttering, and the root region showed higher toughness than upper region of weld.

  3. Dynamics of space welding impact and corresponding safety welding study.

    Science.gov (United States)

    Fragomeni, James M; Nunes, Arthur C

    2004-03-01

    This study was undertaken in order to be sure that no hazard would exist from impingement of hot molten metal particle detachments upon an astronauts space suit during any future electron beam welding exercises or experiments. The conditions under which molten metal detachments might occur in a space welding environment were analyzed. The safety issue is important during welding with regards to potential molten metal detachments from the weld pool and cold filler wire during electron beam welding in space. Theoretical models were developed to predict the possibility and size of the molten metal detachment hazards during the electron beam welding exercises at low earth orbit. Some possible ways of obtaining molten metal drop detachments would include an impulse force, or bump, to the weld sample, cut surface, or filler wire. Theoretical models were determined for these detachment concerns from principles of impact and kinetic energies, surface tension, drop geometry, surface energies, and particle dynamics. A weld pool detachment parameter for specifying the conditions for metal weld pool detachment by impact was derived and correlated to the experimental results. The experimental results were for the most part consistent with the theoretical analysis and predictions.

  4. Industrial laser welding evaluation study

    Science.gov (United States)

    Hella, R.; Locke, E.; Ream, S.

    1974-01-01

    High power laser welding was evaluated for fabricating space vehicle boosters. This evaluation was made for 1/4 in. and 1/2 in. aluminum (2219) and 1/4 in. and 1/2 in. D6AC steel. The Avco HPL 10 kW industrial laser was used to perform the evaluation. The objective has been achieved through the completion of the following technical tasks: (1) parameter study to optimize welding and material parameters; (2) preparation of welded panels for MSFC evaluation; and (3) demonstration of the repeatability of laser welding equipment. In addition, the design concept for a laser welding system capable of welding large space vehicle boosters has been developed.

  5. Effects of soldering and laser welding on bond strength of ceramic to metal.

    Science.gov (United States)

    Aladağ, Akin; Cömlekoğlu, M Erhan; Dündar, Mine; Güngör, M Ali; Artunç, Celal

    2011-01-01

    Welding or soldering of metal frameworks negatively affects the overall bond strength between the veneering ceramic and metal. The purpose of this study was to evaluate the effect of soldering and laser-welding procedures on the bond strength between ceramic and metal. Thirty Ni-based metal specimens (Wiron 99) (8 × 4 × 4 mm) were fabricated and divided into 3 groups; soldered (S), laser welded (L), and control (untreated cast alloy) (n=10). In S and L specimens, a notch (1 × 1.5 mm) was prepared longitudinally on the surface of each specimen and filled with compatible alloy (Wiron soldering rods and Wiroweld NC, respectively). Vickers hardness measurements were made after polishing the surfaces with a metallographic polishing kit. A veneering ceramic (VITA VMK 95) was vibrated, condensed in a mold, and fired on the metal frameworks. The specimens were sectioned in 2 axes to obtain nontrimmed bar specimens with a bonding area of approximately 1 mm². Forty bars per block were obtained. Each bar was subjected to microtensile bond strength (μTBS) testing with a crosshead speed of 1 mm/min. The μTBS data (MPa) were recorded, and SEM was used for failure analysis of the tested bars. The measurements were statistically analyzed using a 1-way ANOVA and Tamhane tests (α=.05). The mean differences in μTBS of veneering ceramic to soldered (10.4 ±2.4 MPa) and laser-welded (11.7 ±1.3 MPa) metal surfaces were not significantly different and were significantly lower than that of the cast alloy (25.4 ±3.6 MPa) (Plaser-welded groups (129 ±11 HV) (Plaser welding significantly decreased the μTBS of a veneering ceramic to a base metal alloy. Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  6. SRμCT study of crack propagation within laser-welded aluminum-alloy T-joints

    Science.gov (United States)

    Herzen, J.; Beckmann, F.; Riekehr, S.; Bayraktar, F. S.; Haibel, A.; Staron, P.; Donath, T.; Utcke, S.; Kocak, M.; Schreyer, A.

    2008-08-01

    Using laser welding in fabrication of metallic airframes reduces the weight and hence fuel consumption. Currently only limited parts of the airframes are welded. To increase laser beam welded parts, there is the need for a better understanding of crack propagation and crack-pore interaction within the welds. Laser beam welded Al-alloys may contain isolated small process pores and their role and interaction with growing crack need to be investigated. The present paper presents the first results of a crack propagation study in laser beam welded (LBW) Al-alloy T-joints using synchrotron radiation based micro computed tomography (SRμCT). A region-of-interest technique was used, since the specimens exceeded the field of view of the X-ray detector. As imaging with high density resolution at high photon energies is very challenging, a feasibility measurement on a small laser weld, cut cylindrically from the welded region of a T-joint, was done before starting the crack-propagation study. This measurement was performed at the beamline HARWI-II at DESY to demonstrate the potential of the SRμCT as non-destructive testing method. The result has shown a high density resolution, hence, the different Al alloys used in the T-joint and the weld itself were clearly separated. The quantitative image analysis of the 3D data sets allows visualizing non-destructively and calculating the pore size distribution.

  7. Spot Welding Parameter Optimization to Improve Weld Characteristics for Dissimilar Metals

    OpenAIRE

    Aravinthan Arumugam; MohdAmizi Nor

    2015-01-01

    Abstract Resistance spot welding is a process which is widely used in the automotive industry to join steel parts of various thicknesses and types. The current practice in the automotive industry in determining the welding schedule which will be used in the welding process is based on welding table or experiences. This however may not be the optimum welding schedule that will give the best spot weld quality. This work concentrates on the parameter optimization when spot welding steels with di...

  8. Pulsed ultrasonic stir welding system

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

    An ultrasonic stir welding system includes a welding head assembly having a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. During a welding operation, ultrasonic pulses are applied to the rod as it rotates about its longitudinal axis. The ultrasonic pulses are applied in such a way that they propagate parallel to the longitudinal axis of the rod.

  9. Viewing Welds By Computer Tomography

    Science.gov (United States)

    Pascua, Antonio G.; Roy, Jagatjit

    1990-01-01

    Computer tomography system used to inspect welds for root penetration. Source illuminates rotating welded part with fan-shaped beam of x rays or gamma rays. Detectors in circular array on opposite side of part intercept beam and convert it into electrical signals. Computer processes signals into image of cross section of weld. Image displayed on video monitor. System offers only nondestructive way to check penetration from outside when inner surfaces inaccessible.

  10. Jointed Holder For Welding Electrodes

    Science.gov (United States)

    Gilbert, Jeffrey L.

    1991-01-01

    Adjustable-angle holder enables use of standard straight electrode with custom-fabricated bent gas cup for welding in difficult-to-reach places. Electrode replaced easily, without removing cup, with aid of tool loosening miniature collet nut on holder. Consumes fewer electrodes for given amount of welding. Angle of holder continuously adjustable to fit angle of gas cup or geometry of part welded. Holder made double-jointed to accommodate gas cup having compound angles.

  11. Effect of laser welding on the titanium ceramic tensile bond strength.

    Science.gov (United States)

    Galo, Rodrigo; Ribeiro, Ricardo Faria; Rodrigues, Renata Cristina Silveira; Pagnano, Valéria de Oliveira; Mattos, Maria da Glória Chiarello de

    2011-08-01

    Titanium reacts strongly with elements, mainly oxygen at high temperature. The high temperature of titanium laser welding modifies the surface, and may interfere on the metal-ceramic tensile bond strength. The influence of laser welding on the titanium-ceramic bonding has not yet been established. The purpose of this in vitro study was to analyze the influence of laser welding applied to commercially pure titanium (CpTi) substructure on the bond strength of commercial ceramic. The influence of airborne particle abrasion (Al2O3) conditions was also studied. Forty CpTi cylindrical rods (3 mm x 60 mm) were cast and divided into 2 groups: with laser welding (L) and without laser welding (WL). Each group was divided in 4 subgroups, according to the size of the particles used in airborne particle abrasion: A - Al2O3 (250 µm); B - Al2O3 (180 µm); C - Al2O3 (110 µm); D - Al2O3 (50 µm). Ceramic rings were fused around the CpTi rods. Specimens were invested and their tensile strength was measured at fracture with a universal testing machine at a crosshead speed of 2.0 mm/min and 200 kgf load cell. Statistical analysis was carried out with analysis of variance and compared using the independent t test (plaser-welded specimens, i.e. the metal-ceramic tensile bond strength was lower.

  12. Reconditioning medical prostheses by welding

    Science.gov (United States)

    Rontescu, C.; Cicic, D. T.; Vasile, I. M.; Bogatu, A. M.; Amza, C. G.

    2017-08-01

    After the technological process of making, some of the medical prostheses may contain imperfections, which can lead to framing the product in the spoilage category. This paper treats the possibility of reconditioning by welding of the prosthesis made of titanium alloys. The paper presents the obtained results after the reconditioning by welding, using the GTAW process, of a intramedullary rod type prosthesis in which was found a crack after the non-destructive examination. The obtained result analysis, after the micrographic examination of the welded joint areas, highlighted that the process of reconditioning by welding can be applied successfully in such situations.

  13. Pulsed ultrasonic stir welding method

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

    A method of performing ultrasonic stir welding uses a welding head assembly to include a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. In the method, the rod is rotated about its longitudinal axis during a welding operation. During the welding operation, a series of on-off ultrasonic pulses are applied to the rod such that they propagate parallel to the rod's longitudinal axis. At least a pulse rate associated with the on-off ultrasonic pulses is controlled.

  14. Effect of laser welding on the titanium composite tensile bond strength.

    Science.gov (United States)

    Galo, Rodrigo; Ribeiro, Ricardo Faria; Rodrigues, Renata Cristina Silveira; Pagnano, Valéria de Oliveira; de Mattos, Maria da Glória Chiarello

    2009-01-01

    The aim of this study was to analyze the shear bond strength between commercially pure titanium, with and without laser welding, after airbone-particle abrasion (Al(2)O(3)) and 2 indirect composites. Sixty-four specimens were cast and divided into 2 groups with and without laser welding. Each group was divided in 4 subgroups, related to Al(2)O(3) grain size: A - 250 microm; B - 180 microm; C- 110 microm; and D - 50 microm. Composite rings were formed around the rods and light polymerized using UniXS unit. Specimens were invested and their shear bond strength at failure was measured with a universal testing machine at a crosshead speed of 2.0 mm/min. Statistical analysis was carried out with ANOVA and Tukey's test (alpha=0.05). The highest bond strength means were recorded in 250 microm group without laser welding. The lowest shear bond strength means were recorded in 50 microm group with laser welding. Statistically significant differences (plaser welded specimens.

  15. Explosive welding underwater

    Energy Technology Data Exchange (ETDEWEB)

    Sim, T.; Allen, K.; Lowes, J.M.

    1980-06-11

    Explosive welding underwater is described. First and second underwater tubular members are assembled together so that the outer surface of the first tubular member and the inner surface of the second tubular member are spaced apart to form an annular cavity. The cavity is closed by seals accommodated in portions of the second tubular member, and is then cleaned and dried and filled with a gas at a pressure greater than the surrounding water pressure. The pressure in the cavity is reduced prior to detonating an explosive charge within the first tubular member to weld the members together. The second tubular member may include portions for receiving further seals so as to subdivide the cavity into a number of zones. The pressures in the zones then can be separately adjusted so as to be able to control the pressure difference a cross each seal. 9 claims.

  16. Numerical simulation of welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær; Thorborg, Jesper

    Aim of project:To analyse and model the transient thermal field from arc welding (SMAW, V-shaped buttweld in 15mm plate) and to some extend the mechanical response due to the thermal field. - To implement this model in a general purpose finite element program such as ABAQUS.The simulation...... is limited to 2D and as regards the thermal model we assume plain cross section when comparing with experiments and analytical solutions.Stresses and deformations based on the thermal model is mainly described qualitatively in relation to the mechanical model in ABAQUS. As regards the mechanical model, plain...... stress is also taken into account.Work carried out:With few means it is possible to define a thermal model which describes the thermal field from the welding process in reasonable agreement with reality. Identical results are found with ABAQUS and Rosenthal’s analytical solution of the governing heat...

  17. Numerical study of the Notch Location of the Impact Test Specimens on the HAZ of SA516 Steels

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yun Chan; Kim, Dong Wook; Lee, Young Seog [Chungang Univ., Seoul (Korea, Republic of); Hong, Jae Keun; Park, Ji Hong [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2007-07-01

    Experimental and numerical studies were performed to examine the effects of notch position on the failure behavior and energy absorption when the Charpy V-notch impact test is made at 1 .deg. C. For this purpose, carbon steel plate (SA-516 Gr. 70) with thickness of 25mm usually used for pressure vessel was welded by SMAW (Shielded Metal-Arc Welding) method and specimens were fabricated from the welded plate. The Charpy impact tests were then performed with specimens having different notch positions varying within HAZ. A series of three-dimensional FE analysis which simulates the Charpy test and crack propagation are carried out as well to examine the reproducibility of test results. The FE analysis takes into account the heterogeneous mechanical properties with complex microstructures in HAZ. Results reveal that the absorbed energies during impact test depend significantly on the notch position.

  18. Application of Factorial Design for Gas Parameter Optimization in CO2 Laser Welding

    DEFF Research Database (Denmark)

    Gong, Hui; Dragsted, Birgitte; Olsen, Flemming Ove

    1997-01-01

    The effect of different gas process parameters involved in CO2 laser welding has been studied by applying two-set of three-level complete factorial designs. In this work 5 gas parameters, gas type, gas flow rate, gas blowing angle, gas nozzle diameter, gas blowing point-offset, are optimized...... to be a very useful tool for parameter optimi-zation in laser welding process. Keywords: CO2 laser welding, gas parameters, factorial design, Analysis of Variance........ The bead-on-plate welding specimens are evaluated by a number of quality char-acteristics, such as the penetration depth and the seam width. The significance of the gas pa-rameters and their interactions are based on the data found by the Analysis of Variance-ANOVA. This statistic methodology is proven...

  19. Microstructure evolution and fracture behaviour for electron beam welding of Ti–6Al–4V

    Indian Academy of Sciences (India)

    Wu Huiqiang; Feng Jicai; He Jingshan

    2004-08-01

    The effect of microstructural characteristics on fracture behaviour mechanism for electron beam welding of Ti–6Al–4V was investigated. The results indicated that the welded microstructure composed of coarse needle + phases presenting disordered and multidirectional short needle morphology to make fracture mechanism complex. The coarse grains in weld seam with microhardness 536 HV were easy to be fractured in the region where welding heat input was ≥ 68.8 kJ/m. There exists flat curves of Ti, Al and V, Fe concentration distribution fluctuation to cause microstructural amplitude-modulated decomposition to increase the joint ductility and cleavage strength. The uneven distribution of the partial micropores located at the interior of the specimen acting as crack initiation sites lead to non-linear branch propagating path. The + interlaced structure results in the fracture location near / interface. The existence of stacking fault structure caused pile-up of dislocation to produce micropores to be new fracture initiation sites.

  20. Prediction of residual stresses in electron beam welded Ti-6Al-4V plates

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Lianyong; Ge, Keke; Jing, Hongyang; Zhao, Lei; Lv, Xiaoqing [Tianjin Univ. (China); Han, Yongdian [Tianjin Univ. (China). Key Lab. of Advanced Joining Technology

    2017-05-01

    A thermo-metallurgical procedure based on the SYSWELD code was developed to predict welding temperature field, microstructure and residual stress in butt-welded Ti-6Al-4V plate taking into account phase transformation. The formation of martensite was confirmed by the CCT diagram and microstructure in the weld joint, which significantly affects the magnitude of residual stress. The hole drilling procedure was utilized to measure the values of residual stress at the top surface of the specimen, which are in well agreement with the numerical results. Both simulated and test results show that the magnitude and distribution of residual stress on the surface of the plate present a large gradient feature from the weld joint to the base metal. Moreover, the distribution law of residual stresses in the plate thickness was further analyzed for better understanding of its generation and evolution.

  1. Study on fracture characteristic of welded high-density polyethylene pipe

    Institute of Scientific and Technical Information of China (English)

    齐芳娟; 霍立兴; 张玉凤; 荆洪阳; 杨新岐

    2002-01-01

    Crack opening displacement(COD) was applied to characterize the fracture initiation of the tough high density polyethylene. Normal single side notched three-point bend specimens and silica rubber replica techniques were used to study the characteristic COD of high-density polyethylene pipe and its butt-fusion joints including the weld fusion zone and heat affected zone at different temperature from -78℃ to 20℃ . Testing results show that the characteristic COD appears to depend on the structural features that are determined by welding process and the testing temperature. As the temperature is lowered, the characteristic COD of all zones studied decreases. Because the welding process significantly changes some structural feature of the material, characteristic COD of the weld fusion zone is the smallest one among those of the three zones. The results can be used for the engineering design and failure analysis of HDPE pipe.

  2. Experimental and Numerical Study on the Strength of Aluminum Extrusion Welding

    Directory of Open Access Journals (Sweden)

    Sedat Bingöl

    2015-07-01

    Full Text Available The quality of extrusion welding in the extruded hollow shapes is influenced significantly by the pressure and effective stress under which the material is being joined inside the welding chamber. However, extrusion welding was not accounted for in the past by the developers of finite element software packages. In this study, the strength of hollow extrusion profile with seam weld produced at different ram speeds was investigated experimentally and numerically. The experiments were performed on an extruded hollow aluminum profile which was suitable to obtain the tensile tests specimens from its seam weld’s region at both parallel to extrusion direction and perpendicular to extrusion direction. A new numerical modeling approach, which was recently proposed in literature, was used for numerical analyses of the study. The simulation results performed at different ram speeds were compared with the experimental results, and a good agreement was obtained.

  3. Influence of the Strength Mismatch of a Narrow Gap Welded Joint of SA508 on the Plastic η Factor

    Science.gov (United States)

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

    2012-11-01

    In this article, the influence of the strength mismatch of a narrow gap welded joint of SA508 on the η factor was evaluated. The η 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 η factor equation considering the strength mismatch and the weld width of a narrow gap welded joint was suggested.

  4. Assessment of The Cracking Properties of Stainless Steel Alloys and their Usability for Laser Welding in Production

    DEFF Research Database (Denmark)

    Juhl, Thomas Winther

    2001-01-01

    Methods to assess stainless steel alloys’ cracking properties and usability for laser welding has been studied. Also tests to assess alloys’ susceptibility to hot cracking has been conducted. Among these is the so-called Weeter test which assesses the alloy by executing a number of spot welds...... to provoke cracking in the alloy. In this work the Weeter test has been modified and changed in order to develop a faster and easier test also applicable to small specimens. The new test, called a Groove test differs from the Weeter test by its procedure in which linear seam welds are conducted instead...... of spot welds. The Groove test has the advantage of an easier microscopy and analysis in the welds. Results from crack tests was partly confirmed by predictions made on the basis of the alloy’s constituents and solidification growth rate....

  5. NEW EXPLOSIVE WELDING TECHNIQUES

    OpenAIRE

    Lotous, V.; Dragobetskii, V.

    2015-01-01

    Purpose - analysis of the variety of factors of the physical phenomena accompanying the process of the power explosive effect for development of new processes of metal treatment: explosive film coating of hardening and updating of a superficial layer of an item. Industrial approbation of cladding techniques by explosion of item surfaces of complex configuration and determination of parameters of the process of the explosive welding of high-strength pig-iron (graphite of the spherical form) wi...

  6. Characterization on strength and toughness of welded joint for Q550 steel

    Indian Academy of Sciences (India)

    Jiang Qinglei; Li Yajiang; Wang Juan; Zhang Lei

    2011-02-01

    Q550 high strength steel was welded using gas shielded arc welding and three different welding wires without pre- or post-heat treatments. The paper investigates the influence of welding wire on the microstructure, tensile strength and impact toughness of Q550 steel weld joints. Results showed that the microstructure of the weld metal of joints produced using ER50-6 wire was a mixture of acicular ferrite and grain boundary ferrite including pro-eutectoid ferrite and ferrite side plate. Acicular ferrite was mainly obtained in the weld metal of the joints produced using MK.G60-1 wire. Pro-eutectoid ferrite was present along the boundary of prior austenite. Crack initiation occurred easily at pro-eutectoid ferrite when the joint was subjected to tensile. Tensile strength and impact toughness were promoted with increasing acicular ferrite. Tensile strength of the joint fabricated using MK.G60-1 wire was close to that of base metal. And tensile samples fractured at location of the fusion zone, which had lower toughness and thus became the weak region in the joint. Impact absorbing energy was the highest in the heat affected zone. Fibrous region in fracture surfaces of impact specimens was characterized as transgranular fracture with the mechanism of micro-void coalescence. Acicular ferrite microstructure region corresponded to relatively large dimples while boundary ferrite microstructure corresponded to small dimples.

  7. Fatigue crack initiation for Al-Zn-Mg alloy welded joint

    Institute of Scientific and Technical Information of China (English)

    Liang ZHANG; Xuesong LIU; Linsen WANG; Ping WANG; Hongyuan FANG

    2012-01-01

    To investigate fatigue crack initiation characteristics of A1-Zn-Mg alloy welded joint,notched specimens were used in fatigue test for the base metal,welding bead and heat affected zone (HAZ).The fatigue fracture surface near the fatigue crack initiation site was observed by scanning electron microscope (SEM).The results show that the differences of fatigue crack initiation life among base metal,welding bead and HAZ are not obvious.Inhomogeneity in microstructure and mechanical performance of HAZ influences the fatigue crack initiation life.The ratio of fatigue crack initiation life (Ni) to fatigue failure life (Nf) for the base metal,welding bead and HAZ of A7N01 aluminium alloy welded joint are 26.32%,40.21% and 60.67%,respectively.Fatigue crack initiation life can be predicted using a uniform model.Observation of fatigue fracture surfaces shows that for the welding bead a fatigue crack initiates from the smooth surface due to the welding process,the blowhole in HAZ causes fatigue crack and the crushed second phase particles play an important role in fatigue crack initiation for the base metal.

  8. Numerical simulation of full-penetration laser beam welding of thick aluminium plates with inductive support

    Science.gov (United States)

    Bachmann, Marcel; Avilov, Vjaceslav; Gumenyuk, Andrey; Rethmeier, Michael

    2012-01-01

    A three-dimensional laminar steady-state numerical model was developed to investigate the influence of an alternating current (ac) magnetic field during high-power full-penetration laser welding on the weld pool dynamics and weld cross section of a 20 mm thick aluminium plate in flat position. Three-dimensional heat transfer, fluid dynamics including phase transition and electromagnetic field partial differential equations were solved iteratively with the commercial finite element software COMSOL Multiphysics using temperature-dependent material properties up to evaporation temperature. Thermocapillary convection at the weld pool surfaces, natural convection and latent heat of solid-liquid phase transition were taken into account in this model. Solidification was modelled by the Carman-Kozeny equation for porous media morphology. The ac magnet was mounted on the root side of the weld specimen. The magnetic field was aligned perpendicular to the welding direction. The flow pattern in the melt and thus also the temperature distribution were significantly changed by the application of oscillating magnetic fields. It was shown that the application of an ac magnetic field to laser beam welding allows for a prevention of the gravity drop-out. The simulation results are in good qualitative agreement with the experimental observations.

  9. Microstructure and Mechanical Properties of Hybrid Welded Joints with Laser and CO2-Shielded Arc

    Science.gov (United States)

    Wahba, M.; Mizutani, M.; Katayama, S.

    2016-07-01

    With the objective of reducing the operating costs, argon-rich shielding gas was replaced by 100% CO2 gas in hybrid laser-arc welding of shipbuilding steel. The welding parameters were optimized to obtain buried-arc transfer in order to mitigate spatter formation. Sound butt joints could be successfully produced for plates of 14 and 17 mm thickness in one welding pass. Subsequently, the welded joints were subjected to different tests to evaluate the influence of CO2 shielding gas on the mechanical properties of the welded joints. All tensile-tested specimens failed in the base material, indicating the higher strength of the welded joints. The impact toughness of the welded joints, measured at -20 °C, reached approximately 76% of that of the base material, which was well above the limit set by the relevant standard. The microstructure of the fusion zone consisted of grain boundary ferrite and acicular ferrite uniformly over the plate thickness except for the joint root where the microstructure was chiefly ferrite with an aligned second phase. This resulted in higher hardness in the root region compared with the top and middle parts of the fusion zone.

  10. Experimental determination of the critical welding speed in high speed MAG welding

    Institute of Scientific and Technical Information of China (English)

    Hu Zhikun; Wu Chuansong

    2008-01-01

    In high speed MAG welding process, some weld formation defects may be encountered. To get good weld quality, the critical welding speed beyond which humping or undercutting weld bead can occur must be known for different conditions. In this research, high speed MAG welding tests were carried out to check out the effects of different factors on the critical welding speed. Through observing the weld bead profiles and the macrographs of the transverse sections of MAG welds, the occurrence tendency of humping weld was analyzed, and the values of critical welding speed were determined under different levels of welding current or voltage, and the effect of shielding gas compositions on the critical welding speed was also investigated.

  11. Gas Metal Arc Welding. Welding Module 5. Instructor's Guide.

    Science.gov (United States)

    Missouri Univ., Columbia. Instructional Materials Lab.

    This guide is intended to assist vocational educators in teaching an eight-unit module in gas metal arc welding. The module is part of a welding curriculum that has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The following topics are covered in the module: safety and testing, gas metal arc…

  12. Shielded Metal Arc Welding. Welding Module 4. Instructor's Guide.

    Science.gov (United States)

    Missouri Univ., Columbia. Instructional Materials Lab.

    This guide is intended to assist vocational educators in teaching an eight-unit module in shielded metal arc welding. The module is part of a welding curriculum that has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The following topics are covered in the module: safety; theory, power sources, and…

  13. Gas Tungsten Arc Welding. Welding Module 6. Instructor's Guide.

    Science.gov (United States)

    Missouri Univ., Columbia. Instructional Materials Lab.

    This guide is intended to assist vocational educators in teaching a three-unit module in gas tungsten arc welding. The module has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The basic principles involved in gas tungsten arc welding, supplies, and applications are covered. The materials included…

  14. Effects of Fusion Tack Welds on Self-Reacting Friction Stir Welds

    Science.gov (United States)

    Nunes, A. C., Jr.; Pendleton, M. L.; Brooke, S. A.; Russell, C. K.

    2012-01-01

    In order to know whether fusion tack welds would affect the strength of self-reacting friction stir seam welds in 2195-T87 aluminum alloy, the fracture stresses of 144 tensile test coupons cut from 24 welded panels containing segments of friction stir welds were measured. Each of the panels was welded under unique processing conditions. A measure of the effect of the tack welds for each panel was devised. An analysis of the measures of the tack weld effect supported the hypothesis that fusion tack welds do not affect the strength of self-reacting friction stir welds to a 5% level of confidence.

  15. Boundary effects in welded steel moment connections

    Science.gov (United States)

    Lee, Kyoung-Hyeog

    Unprecedented widespread failure of welded moment connections in steel frames caused by the 1994 Northridge and the 1995 Kobe earthquakes have alarmed the engineering communities throughout the world. Welded moment connections in steel frames have been traditionally designed by using the classical beam theory which leads to assumptions that the flanges transfer moment while the web connection primarily resists the shear force. However, this study shows that the magnitude and direction of the principal stresses in the connection region are better approximated by using truss analogy rather than the classical beam theory. Accordingly, both the bending moment and the shear force are transferred across the connection near the beam flanges through diagonal strut action. Thus, the beam flange region of the traditionally designed connection is overloaded. This conclusion explains, to a large extent, the recently observed steel moment connection failures. In this study, detailed finite element analyses were carried out for a representative beam-to-column subassemblage with fully welded connection. The stress distribution in the beam web and flanges in the vicinity of the connection were closely studied. The factors responsible for stress redistribution and concentration were identified by using fundamental principles of mechanics. It was concluded that peak resultant stresses can exceed the values used in simple design calculations by large margins. Using the finite element analysis results and the truss analogy to establish a realistic load path in the connection, a practical and more rational analysis and design procedure was developed. The proposed design procedure and the new connection details were successfully validated through cyclic load testing of a nearly full size specimen. The truss model represented the force transmission around the beam-to-column moment connection region very well. Results of the finite element analyses and the laboratory testing showed

  16. Vision-based detection of MAG weld pool

    Institute of Scientific and Technical Information of China (English)

    Gao Jinqiang; Wu Chuansong; Zhang Min; Zhao Yanhua

    2007-01-01

    Weld pool contains significant information about the welding process. The weld pool images of MAG welding are detected by LaserStrobe system. An algorithm for extracting weld pool edge is proposed according to the characteristics of MAG weld pool images. The maximum weld pool length and width are calculated. The measurement data can be used to verify the results of welding process simulation and to provide a good foundation for automatic control of MAG welding process.

  17. Modeling Stress-Strain State in Butt-Welded Joints after TIG Welding

    Directory of Open Access Journals (Sweden)

    V. Atroshenko

    2015-09-01

    Full Text Available In this paper mathematical model was developed for definition of thermal-welding cycle influence on welding deformations distribution in flat samples of austenitic steels after TIG welding and developed recommendations to reduce the welding deformation on o the machinery for welding with a copper backing.

  18. Reproducibility of pop-ins in laboratory testing of welded joints

    Directory of Open Access Journals (Sweden)

    Berejnoi C.

    2000-01-01

    Full Text Available The pop-in phenomenon, quite common in fracture mechanics tests of welded joints, corresponds to a brittle crack initiation grown from a local brittle zone (LBZ that is arrested in reaching the higher toughness material that surrounds this LBZ. A methodology to obtain a high percentage of pop-in occurrence in laboratory testing is necessary to study the pop-in significance. Such a method is introduced in this work and includes the consumable combination and welding procedures for the SMAW welding process to generate artificial LBZ. In order to find out the influence of the loading state upon the pop-in phenomenon, laboratory CTOD tests were performed using two specimen configurations: some single edge-notched specimens were loaded on a three-point bending (SE(B fixture while others were tested in tensile load (SE(T. A higher frequency of pop-in occurrence was observed in the SE(B geometry.

  19. Microstructure and anisotropic mechanical behavior of friction stir welded AA2024 alloy sheets

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhihan [State Key Laboratory of Solidification Processing, Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi' an 710072, Shaanxi (China); Li, Wenya, E-mail: liwy@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi' an 710072, Shaanxi (China); Li, Jinglong [State Key Laboratory of Solidification Processing, Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi' an 710072, Shaanxi (China); Chao, Y.J. [Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208 (United States); Vairis, A. [Mechanical Engineering Department, TEI of Crete, Heraklion, Crete 71004 (Greece)

    2015-09-15

    The anisotropic mechanical properties of friction stir welded (FSW) AA2024-T3 alloy joints were investigated based on the uniaxial tensile tests. The joint microstructure was examined by using electron back-scattered diffraction and transmission electron microscope. Results show that the evident anisotropic failure and yielding are present in the FSW joints. With the increase of loading angle from 0° to 90° the ultimate tensile strength and elongation of the specimens consistently decrease, or at first decrease and then increase, depending on the FSW process parameters. The specimen cut from the weld direction, i.e. a loading angle of 0°, exhibits the highest strength and elongation. - Highlights: • Microstructure and anisotropy of friction stir welded joints were studied. • The evident anisotropic failure and yielding are present in joints. • The lowest yield stress and UTS are at 45° and 60° loadings, respectively. • Rotation speed heavily impact on the anisotropy of joints.

  20. [New welding processes and health effects of welding].

    Science.gov (United States)

    La Vecchia, G Marina; Maestrelli, Piero

    2011-01-01

    This paper describes some of the recent developments in the control technology to enhance capability of Pulse Gas Metal Arc Welding. Friction Stir Welding (FSW) processing has been also considered. FSW is a new solid-state joining technique. Heat generated by friction at the rotating tool softens the material being welded. FSW can be considered a green and energy-efficient technique without deleterious fumes, gas, radiation, and noise. Application of new welding processes is limited and studies on health effects in exposed workers are lacking. Acute and chronic health effects of conventional welding have been described. Metal fume fever and cross-shift decline of lung function are the main acute respiratory effects. Skin and eyes may be affected by heat, electricity and UV radiations. Chronic effects on respiratory system include chronic bronchitis, a benign pneumoconiosis (siderosis), asthma, and a possible increase in the incidence of lung cancer. Pulmonary infections are increased in terms of severity, duration, and frequency among welders.

  1. The Effect of Constant and Pulsed Current Gas Tungsten Arc Welding on Joint Properties of 2205 Duplex Stainless Steel to 316L Austenitic Stainless Steel

    Science.gov (United States)

    Neissi, R.; Shamanian, M.; Hajihashemi, M.

    2016-05-01

    In this study, dissimilar 316L austenitic stainless steel/2205 duplex stainless steel (DSS) joints were fabricated by constant and pulsed current gas tungsten arc welding process using ER2209 DSS as a filler metal. Microstructures and joint properties were characterized using optical and electron scanning microscopy, tensile, Charpy V-notch impact and micro-hardness tests, and cyclic polarization measurements. Microstructural observations confirmed the presence of chromium nitride and delta ferrite in the heat-affected zone of DSS and 316L, respectively. In addition, there was some deviation in the austenite/ferrite ratio of the surface welding pass in comparison to the root welding pass. Besides having lower pitting potential, welded joints produced by constant current gas tungsten arc welding process, consisted of some brittle sigma phase precipitates, which resulted in some impact energy reduction. The tensile tests showed high tensile strength for the weld joints in which all the specimens were broken in 316L base metal.

  2. Finite element modelling and updating of friction stir welding (FSW joint for vibration analysis

    Directory of Open Access Journals (Sweden)

    Zahari Siti Norazila

    2017-01-01

    Full Text Available Friction stir welding of aluminium alloys widely used in automotive and aerospace application due to its advanced and lightweight properties. The behaviour of FSW joints plays a significant role in the dynamic characteristic of the structure due to its complexities and uncertainties therefore the representation of an accurate finite element model of these joints become a research issue. In this paper, various finite elements (FE modelling technique for prediction of dynamic properties of sheet metal jointed by friction stir welding will be presented. Firstly, nine set of flat plate with different series of aluminium alloy; AA7075 and AA6061 joined by FSW are used. Nine set of specimen was fabricated using various types of welding parameters. In order to find the most optimum set of FSW plate, the finite element model using equivalence technique was developed and the model validated using experimental modal analysis (EMA on nine set of specimen and finite element analysis (FEA. Three types of modelling were engaged in this study; rigid body element Type 2 (RBE2, bar element (CBAR and spot weld element connector (CWELD. CBAR element was chosen to represent weld model for FSW joints due to its accurate prediction of mode shapes and contains an updating parameter for weld modelling compare to other weld modelling. Model updating was performed to improve correlation between EMA and FEA and before proceeds to updating, sensitivity analysis was done to select the most sensitive updating parameter. After perform model updating, total error of the natural frequencies for CBAR model is improved significantly. Therefore, CBAR element was selected as the most reliable element in FE to represent FSW weld joint.

  3. A Comparison of Residual Stress Development in Inertia Friction Welded Fine Grain and Coarse Grain Nickel-Base Superalloy

    Science.gov (United States)

    Iqbal, N.; Rolph, J.; Moat, R.; Hughes, D.; Hofmann, M.; Kelleher, J.; Baxter, G.; Withers, P. J.; Preuss, M.

    2011-12-01

    The effect of the base material microstructure on the development of residual stresses across the weld line in inertia friction welds (IFWs) of high-strength nickel-base superalloy RR1000 was studied using neutron diffraction. A comparison was carried out between tubular IFW specimens generated from RR1000 heat treated below (fine grain (FG) structure) and above (coarse grain (CG) structure) the γ'-solvus. Residual stresses were mapped in the as-welded (AW) condition and, after a postweld heat treatment (PWHT), optimized for maximum alloy strength. The highest tensile stresses were generally found in the hoop direction at the weld line near the inner diameter of the tubular-shaped specimens. A comparison between the residual stresses generated in FG and CG RR1000 suggests that the starting microstructure has little influence on the maximum residual stresses generated in the weld even though different levels of energy must be input to achieve a successful weld in each case. The residual stresses in the postweld heat treated samples were about 35 pct less than for the AW condition. Despite the fact that the high-temperature properties of the two parent microstructures are different, no significant differences in terms of stress relief were found between the FG and CG RR1000 IFWs. Since the actual weld microstructures of FG and CG RR1000 inertia welds are very similar, the results suggest that it is the weld microstructure and its associated high-temperature properties rather than the parent material that affects the overall weld stress distribution and its subsequent stress relief.

  4. The Effect of Temperature on the Breakdown and Repassivation Potentials of Welded Alloy 22 In 5 M CACI2

    Energy Technology Data Exchange (ETDEWEB)

    G.O. IIevbare

    2006-07-05

    The study of the electrochemical behavior of wrought and welded Alloy 22 was carried out in 5 M CaCl{sub 2} as a function of temperatures between 45 and 120 C with Multiple Crevice Assembly (MCA) specimens. The susceptibility to corrosion was found to increase with increase in electrolyte temperature in both the wrought (in the mill annealed condition) and the welded forms of the alloy. The weld metal was found to be less susceptible to localized corrosion under the conditions tested.

  5. Effect of a shear modified Gurson model on damage development in a FSW tensile specimen

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Tvergaard, Viggo

    2009-01-01

    For a friction stir welded aluminum plate the resistance to ductile failure is studied by analyzing tensile test specimens cut out across the weldline. As the stress triaxiality is rather low in these tests, the Gurson material model is not expected to give a very accurate description of the void...... growth to coalescence. A recently proposed modified version of the Gurson model is used, in which an extra term in the damage evolution law allows for the prediction of failure even at zero or negative values of the mean stress. This modification of the Gurson model is purely phenomenological......, such that the damage parameter does not really represent the void volume fraction. Various amounts of the additional damage evolution are compared with predictions of the original Gurson model. The analyses are carried out for different yield stress profiles transverse to the weld and for different specimen widths...

  6. Parametric Optimization Of Gas Metal Arc Welding Process By Using Grey Based Taguchi Method On Aisi 409 Ferritic Stainless Steel

    Science.gov (United States)

    Ghosh, Nabendu; Kumar, Pradip; Nandi, Goutam

    2016-10-01

    Welding input process parameters play a very significant role in determining the quality of the welded joint. Only by properly controlling every element of the process can product quality be controlled. For better quality of MIG welding of Ferritic stainless steel AISI 409, precise control of process parameters, parametric optimization of the process parameters, prediction and control of the desired responses (quality indices) etc., continued and elaborate experiments, analysis and modeling are needed. A data of knowledge - base may thus be generated which may be utilized by the practicing engineers and technicians to produce good quality weld more precisely, reliably and predictively. In the present work, X-ray radiographic test has been conducted in order to detect surface and sub-surface defects of weld specimens made of Ferritic stainless steel. The quality of the weld has been evaluated in terms of yield strength, ultimate tensile strength and percentage of elongation of the welded specimens. The observed data have been interpreted, discussed and analyzed by considering ultimate tensile strength ,yield strength and percentage elongation combined with use of Grey-Taguchi methodology.

  7. New explosive seam welding concepts

    Science.gov (United States)

    Bement, L. J.

    1973-01-01

    Recently developed techniques provide totally-confined linear explosive seam welding and produce scarf joint with linear explosive seam welding. Linear ribbon explosives are utilized in making narrow, continuous, airtight joints in variety of aluminum alloys, titanium, copper, brass, and stainless steel.

  8. Shedding Light on Laser Welding

    NARCIS (Netherlands)

    Aalderink, B.J.; Aalderink, Benno; Aarts, Ronald G.K.M.; Jonker, Jan B.; Meijer, J.

    2005-01-01

    Nd:YAG laser welding is often used in industry to obtain high quality joints. This however does not mean that monitoring or control of this process is common practice. A few commercial products are available but none of these systems can be used for monitoring the laser welding process of aluminium.

  9. Plasticity Theory of Fillet Welds

    DEFF Research Database (Denmark)

    Hansen, Thomas

    2005-01-01

    This paper deals with simple methods for calculation of fillet welds based on the theory of plasticity. In developing the solutions the lower-bound theorem is used. The welding material and parts of the base material are subdivided into triangular regions with homogeneous stress fields; thereby...

  10. Numerical simulation of linear fiction welding (LFW) processes

    Science.gov (United States)

    Fratini, L.; La Spisa, D.

    2011-05-01

    Solid state welding processes are becoming increasingly important due to a large number of advantages related to joining "unweldable" materials and in particular light weight alloys. Linear friction welding (LFW) has been used successfully to bond non-axisymmetric components of a range of materials including titanium alloys, steels, aluminum alloys, nickel, copper, and also dissimilar material combinations. The technique is useful in the research of quality of the joints and in reducing costs of components and parts of the aeronautic and automotive industries. LFW involves parts to be welded through the relative reciprocating motion of two components under an axial force. In such process the heat source is given by the frictional forces work decaying into heat determining a local softening of the material and proper bonding conditions due to both the temperature increase and the local pressure of the two edges to be welded. This paper is a comparative test between the numerical model in two dimensions, i.e. in plane strain conditions, and in three dimensions of a LFW process of AISI1045 steel specimens. It must be observed that the 3D model assures a faithful simulation of the actual threedimensional material flow, even if the two-dimensional simulation computational times are very short, a few hours instead of several ones as the 3D model. The obtained results were compared with experimental values found out in the scientific literature.

  11. Butt-welding Residual Stress of Heat Treatable Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    C.M. Cheng

    2007-01-01

    This study, taking three types of aluminum alloys 2024-T351, 6061-T6 and 7075-T6 as experimental materials, conducted single V-groove GTAW (gas tungsten arc welding) butt-welding to analyze and compare the magnitude and differences of residual stress in the three aluminum alloys at different single V-groove angles and in restrained or unrestrained conditions. The results show that the larger the grooving angle of butt joint, the higher the residual tensile stress. Too small grooving angle will lead to dramatic differences due to the amount of welding bead filler metal and pre-set joint geometry. Therefore, only an appropriate grooving angle can reduce residual stress. While welding, weldment in restrained condition will lead to a larger residual stress. Also, a residual stress will arise from the restraint position. The ultimate residual stress of weldment is determined by material yield strength at equilibrium temperature. The higher the yield strength at equilibrium temperature, the higher the material residual stress. Because of its larger thermal conductivity, aluminum alloy test specimens have small temperature differential. Therefore, the residual tensile stress of all materials is lower than their yield strength.

  12. TRANSMISSION ELECTRON MICROSCOPY STUDY OF HELIUM BEARING FUSION WELDS

    Energy Technology Data Exchange (ETDEWEB)

    Tosten, M; Michael Morgan, M

    2008-12-12

    A transmission electron microscopy (TEM) study was conducted to characterize the helium bubble distributions in tritium-charged-and-aged 304L and 21Cr-6Ni-9Mn stainless steel fusion welds containing approximately 150 appm helium-3. TEM foils were prepared from C-shaped fracture toughness test specimens containing {delta} ferrite levels ranging from 4 to 33 volume percent. The weld microstructures in the low ferrite welds consisted mostly of austenite and discontinuous, skeletal {delta} ferrite. In welds with higher levels of {delta} ferrite, the ferrite was more continuous and, in some areas of the 33 volume percent sample, was the matrix/majority phase. The helium bubble microstructures observed were similar in all samples. Bubbles were found in the austenite but not in the {delta} ferrite. In the austenite, bubbles had nucleated homogeneously in the grain interiors and heterogeneously on dislocations. Bubbles were not found on any austenite/austenite grain boundaries or at the austenite/{delta} ferrite interphase interfaces. Bubbles were not observed in the {delta} ferrite because of the combined effects of the low solubility and rapid diffusion of tritium through the {delta} ferrite which limited the amount of helium present to form visible bubbles.

  13. 49 CFR 179.300-9 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.300-9 Section 179.300-9... Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-9 Welding. (a) Longitudinal... fusion welded on class DOT-110A tanks. Welding procedures, welders and fabricators must be approved...

  14. METHOD AND SYSTEM FOR LASER WELDING

    DEFF Research Database (Denmark)

    2008-01-01

    The invention relates to laser welding of at least two adjacent, abutting or overlapping work pieces in a welding direction using multiple laser beams guided to a welding region, wherein at least two of the multiple laser beams are coupled into the welding region so as to form a melt and at least...

  15. Image Control In Automatic Welding Vision System

    Science.gov (United States)

    Richardson, Richard W.

    1988-01-01

    Orientation and brightness varied to suit welding conditions. Commands from vision-system computer drive servomotors on iris and Dove prism, providing proper light level and image orientation. Optical-fiber bundle carries view of weld area as viewed along axis of welding electrode. Image processing described in companion article, "Processing Welding Images for Robot Control" (MFS-26036).

  16. Friction Stir Welding of Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    FU Zhi-hong; HE Di-qiu; WANG Hong

    2004-01-01

    Friction stir welding(FSW), a new solid-state welding technology invited in the early 1990s,enables us weld aluminum alloys and titanium alloys etc. The processing of FSW, the microstructure in FSW alloysand the factors influencing weld quality are introduced. The complex factors affecting the properties are researched.

  17. Image Control In Automatic Welding Vision System

    Science.gov (United States)

    Richardson, Richard W.

    1988-01-01

    Orientation and brightness varied to suit welding conditions. Commands from vision-system computer drive servomotors on iris and Dove prism, providing proper light level and image orientation. Optical-fiber bundle carries view of weld area as viewed along axis of welding electrode. Image processing described in companion article, "Processing Welding Images for Robot Control" (MFS-26036).

  18. Towards a Map of Solidification Cracking Risk in Laser Welding of Austenitic Stainless Steels

    Science.gov (United States)

    Bermejo, María-Asunción Valiente; DebRoy, Tarasankar; Hurtig, Kjell; Karlsson, Leif; Svensson, Lars-Erik

    In this work, two series of specimens with Hammar and Svensson's Cr- and Ni-equivalents (Creq+Nieq) = 35 and 45 wt% were used to cover a wide range of austenitic grades. These were laser welded with different energy inputs achieving cooling rates in the range of 103 °C/s to 104 °C/s. As high cooling rates and rapid solidification conditions could favour fully austenitic solidification and therefore raise susceptibility to solidification cracking, the solidification modes of the laser welded specimens were compared to the ones experienced by the same alloys under arc welding conditions. It was found that high cooling rates experienced in laser welding promoted fully austenitic solidification for a wider range of compositions, for example specimens with (Creq+Nieq) = 35% under arc welding cooling conditions at 10 °C/s showed fully austenitic solidification up to Creq/Nieq = 1.30, whilst the same specimens laser cooled at 103 °C/s showed fully austenitic solidification up to Creq/Nieq = 1.50 and those cooled at 104 °C/s showed it up to Creq/Nieq = 1.68. Therefore, high cooling rates extended the solidification cracking risk to a wider range of Creq/Nieq values. This work also compares the cooling rates experimentally determined by thermocouples to the computed cooling rates calculated by a highly-advanced computational model. The distance between the thermocouple's wires and the thermal resistance of thermocouples together with the small size of the weld pools proved to be practical limitations in the experimental determination of cooling rates. However, an excellent agreement was found between computed and experimental solidus isotherms at high energy input settings. For low energy input settings cooling rate was in the order of magnitude of 104 °C/s, whilst for high energy input settings cooling rate was found to be in the order of magnitude of 103 °C/s.

  19. Effects of Heat Treatment on Interface Microstructure and Mechanical Properties of Explosively Welded Ck60/St37 Plates

    Science.gov (United States)

    Yazdani, Majid; Toroghinejad, Mohammad Reza; Hashemi, Seyyed Mohammad

    2016-12-01

    This study explores the effects of heat treatment on the microstructure and mechanical properties of explosively welded Ck60 steel/St37 steel. The objective is to find an economical way for manufacturing bimetallic plates that can be used in the rolling stand of hot rolling mill units. The explosive ratio and stand-off distance are set at 1.7 and 1.5 t ( t = flyer thickness), respectively. Since explosive welding is accompanied by such undesirable metallurgical effects as remarkable hardening, severe plastic deformation, and even formation of local melted zones near the interface, heat treatment is required to overcome or alleviate these adverse effects. For this purpose, the composites are subjected to heat treatment in a temperature range of 600-700 °C at a rate of 90 °C/h for 1 h. Results demonstrate well-bonded composite plates with a wavy interface. In the as-welded case, vortex zones are formed along the interface; however, they are transformed into fine grains upon heat treatment. Microhardness is also observed to be maximum near the interface in the welded case before it decreases with increasing temperature. Shear strength is the highest in the as-welded specimen, which later decreases as a result of heat treatment. Moreover, the energy absorbed by the heat-treated specimens is observed to increase with increasing temperature so that the lowest value of absorbed energy belongs to the as-welded specimen. Finally, fractography is carried out using the scanning electron microscope to examine the specimens subjected to shear and impact tests. As a result of heat treatment, fracture surfaces exhibit dimpled ruptures and fail in the mixed mode, while failure in the as-welded specimens predominantly occurs in the brittle mode.

  20. Corrosion in artificial saliva of a Ni-Cr-based dental alloy joined by TIG welding and conventional brazing.

    Science.gov (United States)

    Matos, Irma C; Bastos, Ivan N; Diniz, Marília G; de Miranda, Mauro S

    2015-08-01

    Fixed prosthesis and partial dental prosthesis frameworks are usually made from welded Ni-Cr-based alloys. These structures can corrode in saliva and have to be investigated to establish their safety. The purpose of this study was to evaluate the corrosion behavior of joints joined by tungsten inert gas (TIG) welding and conventional brazing in specimens made of commercial Ni-Cr alloy in Fusayama artificial saliva at 37°C (pH 2.5 and 5.5). Eighteen Ni-Cr base metal specimens were cast and welded by brazing or tungsten inert gas methods. The specimens were divided into 3 groups (base metal, 2 welded specimens), and the composition and microstructure were qualitatively evaluated. The results of potential corrosion and corrosion current density were analyzed with a 1-way analysis of variance and the Tukey test for pairwise comparisons (α=.05). Base metal and tungsten inert gas welded material showed equivalent results in electrochemical corrosion tests, while the air-torched specimens exhibited low corrosion resistance. The performance was worst at pH 2.5. These results suggest that tungsten inert gas is a suitable welding process for use in dentistry, because the final microstructure does not reduce the corrosion resistance in artificial saliva at 37°C, even in a corrosion-testing medium that facilitates galvanic corrosion processes. Moreover, the corrosion current density of brazed Ni-Cr alloy joints was significantly higher (P<.001) than the base metal and tungsten inert gas welded joints. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  1. Explosive welding finds uses offshore

    Energy Technology Data Exchange (ETDEWEB)

    1984-02-01

    This article discusses an explosive welding procedure for pipeline repair. Unlike fusion welding, explosive welding does not leave a brittle area behind and will stop axial or longitudinal cracking of a pipeline. The metals are joined by cold impact pressure, which actually liquifies the metal at the point of impact. In explosive welding, the force of the circular explosion drives the two metals together with such an impact that a bonded wave pattern is set up. All surface defects and oxides are pushed ahead of the collision front, resulting in a metal-to-metal seal. Two techniques are reviewed: the Exploweld method and the Norabel method. Both methods do not reduce or expand the internal diameter of the welded surface.

  2. 2003 Dead Bald Eagle Specimen

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The specimen report states the Bald Eagle was found along the side of the I-95 by a motorist who contacted Santee National Wildlife Refuge. The Bald Eagle was taken...

  3. Reduction of Biomechanical and Welding Fume Exposures in Stud Welding.

    Science.gov (United States)

    Fethke, Nathan B; Peters, Thomas M; Leonard, Stephanie; Metwali, Mahmoud; Mudunkotuwa, Imali A

    2016-04-01

    The welding of shear stud connectors to structural steel in construction requires a prolonged stooped posture that exposes ironworkers to biomechanical and welding fume hazards. In this study, biomechanical and welding fume exposures during stud welding using conventional methods were compared to exposures associated with use of a prototype system that allowed participants to weld from an upright position. The effect of base material (i.e. bare structural beam versus galvanized decking) on welding fume concentration (particle number and mass), particle size distribution, and particle composition was also explored. Thirty participants completed a series of stud welding simulations in a local apprenticeship training facility. Use of the upright system was associated with substantial reductions in trunk inclination and the activity levels of several muscle groups. Inhalable mass concentrations of welding fume (averaged over ~18 min) when using conventional methods were high (18.2 mg m(-3) for bare beam; 65.7 mg m(-3) for through deck), with estimated mass concentrations of iron (7.8 mg m(-3) for bare beam; 15.8 mg m(-3) for through deck), zinc (0.2 mg m(-3) for bare beam; 15.8 mg m(-3) for through deck), and manganese (0.9 mg m(-3) for bare beam; 1.5 mg m(-3) for through deck) often exceeding the American Conference of Governmental Industrial Hygienists Threshold Limit Values (TLVs). Number and mass concentrations were substantially reduced when using the upright system, although the total inhalable mass concentration remained above the TLV when welding through decking. The average diameters of the welding fume particles for both bare beam (31±17 nm) through deck conditions (34±34 nm) and the chemical composition of the particles indicated the presence of metallic nanoparticles. Stud welding exposes ironworkers to potentially high levels of biomechanical loading (primarily to the low back) and welding fume. The upright system used in this study improved exposure

  4. Reheat cracking susceptibility of P23 (7CrWVMoNb9-6) steel welds made using matching and mis-matching filler metals

    Energy Technology Data Exchange (ETDEWEB)

    Nevasmaa, Pekka; Salonen, Jorma; Auerkari, Pertti; Rantala, Juhani; Holmstroem, Stefan [VTT Technical Research Centre of Finland, Espoo (Finland)

    2010-07-01

    Reheat cracking sensitivity of 7CrWVMoNb9-6 (P23) thick-section multipass welds has been investigated by Gleeble simulation, mechanical testing, fractography and metallography. The results demonstrate that the experimental weld metal made using a high-Nb-W-Ti-B type filler metal was sensitive to reheat cracking, with a reduction of area no more than 2-3% in the BWI reheat cracking (RC) test. Welds made using a high-W -low-Ti type filler metal with Nb content similar to the parent steel, as well as welds make using a Ni-Nb-Ti-free-(W-free) type filler metal with the chemical composition closer to P24 grade material, were more ductile and crack-resistant, though with reduced cross-weld creep strength. Fractography of RC test specimens showed evidence of pronounced localisation of damage at the prior austenite grain boundaries of the thermally reheated, experimental P23 weld metal. The reheat cracking susceptibility of the less ductile weld metal was apparently related both to the chemical composition (higher B, Nb and Ti content) and sub-structural features of the coarse-grained reheated weld metal microstructure. Appropriate single- and multi-cycle thermal Gleeble simulations to produce representative HAY and reheated weld metal microstructures (as function of peak temperature), in conjunction with the BWI RC test were successfully applied to characterise the reheat cracking sensitivity of the candidate weld metals and parent steel HAZ. (orig.)

  5. Electrophoretic mobility patterns of collagen following laser welding

    Science.gov (United States)

    Bass, Lawrence S.; Moazami, Nader; Pocsidio, Joanne O.; Oz, Mehmet C.; LoGerfo, Paul; Treat, Michael R.

    1991-06-01

    Clinical application of laser vascular anastomosis in inhibited by a lack of understanding of its mechanism. Whether tissue fusion results from covalent or non-covalent bonding of collagen and other structural proteins is unknown. We compared electrophoretic mobility of collagen in laser treated and untreated specimens of rat tail tendon (>90% type I collagen) and rabbit aorta. Welding was performed, using tissue shrinkage as the clinical endpoint, using the 808 nm diode laser (power density 14 watts/cm2) and topical indocyanine green dye (max absorption 805 nm). Collagen was extracted with 8 M urea (denaturing), 0.5 M acetic acid (non-denaturing) and acetic acid/pepsin (cleaves non- helical protein). Mobility patterns on gel electrophoresis (SDS-PAGE) after urea or acetic acid extraction were identical in the lasered and control tendon and vessel (confirmed by optical densitometry), revealing no evidence of formation of novel covalent bonds. Alpha and beta band intensity was diminished in pepsin incubated lasered specimens compared with controls (optical density ratio 0.00 +/- 9 tendon, 0.65 +/- 0.12 aorta), indicating the presence of denatured collagen. With the laser parameters used, collagen is denatured without formation of covalent bonds, suggesting that non-covalent interaction between denatured collagen molecules may be responsible for the weld. Based on this mechanism, welding parameters can be chosen which produce collagen denaturation without cell death.

  6. Manufacturing of Plutonium Tensile Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, Cameron M [Los Alamos National Laboratory

    2012-08-01

    Details workflow conducted to manufacture high density alpha Plutonium tensile specimens to support Los Alamos National Laboratory's science campaigns. Introduces topics including the metallurgical challenge of Plutonium and the use of high performance super-computing to drive design. Addresses the utilization of Abaqus finite element analysis, programmable computer numerical controlled (CNC) machining, as well as glove box ergonomics and safety in order to design a process that will yield high quality Plutonium tensile specimens.

  7. Spot Welding Parameter Optimization to Improve Weld Characteristics for Dissimilar Metals

    Directory of Open Access Journals (Sweden)

    Aravinthan Arumugam

    2015-01-01

    Full Text Available Abstract Resistance spot welding is a process which is widely used in the automotive industry to join steel parts of various thicknesses and types. The current practice in the automotive industry in determining the welding schedule which will be used in the welding process is based on welding table or experiences. This however may not be the optimum welding schedule that will give the best spot weld quality. This work concentrates on the parameter optimization when spot welding steels with dissimilar thickness and type using Grey Based Taguchi Method. The experimentation in this work used a L9 orthogonal array with three factors with each factor having three levels. The three factors used are welding current weld time and electrode force. The three weld characteristics that were optimized are weld strength weld nugget diameter and weld indentation. The analysis of variance ANOVA that was carried out showed that welding current gave the most significant contribution in the optimum welding schedule. The comparison test that was carried out to compare the current welding schedule and the optimum welding schedule showed distinct improvement in the increase of weld diameter and weld strengthas well as decrease in electrode indentation.

  8. Friction stir welding of copper alloys

    Institute of Scientific and Technical Information of China (English)

    Liu Shuhua; Liu Meng; Wang Deqing; Xu Zhenyue

    2007-01-01

    Copper plates,brass plates and copper/brass plates were friction stir welded with various parameters. Experimental results show that the microstructure of the weld is characterized by its much finer grains as contrasted with the coarse grains of parent materials and the heat-affected zones are very narrow. The microhardness of the copper weld is a little higher than that of parent plate. The microhardness of brass weld is about 25% higher than that of parent material. The tensile strength of copper joints increases with increasing welding speed in the test range. The range of parameters to obtain good welds for copper is much wider than that for brass. When different materials were welded, the position of copper plate before welding affected the quality of FSW joints. If the copper plate was put on the advancing side of weld, the good quality of weld could be got under proper parameters.

  9. Interface morphology and mechanical properties of Al-Cu-Al laminated composites fabricated by explosive welding and subsequent rolling process

    Science.gov (United States)

    Hoseini-Athar, M. M.; Tolaminejad, B.

    2016-07-01

    Explosive welding is a well-known solid state method for joining similar and dissimilar materials. In the present study, tri-layered Al-Cu-Al laminated composites with different interface morphologies were fabricated by explosive welding and subsequent rolling. Effects of explosive ratio and rolling thickness reduction on the morphology of interface and mechanical properties were evaluated through optical/scanning electron microscopy, micro-hardness, tensile and tensile-shear tests. Results showed that by increasing the thickness reduction, bonding strength of specimens including straight and wavy interfaces increases. However, bonding strength of the specimens with melted layer interface decreases up to a threshold thickness reduction, then rapidly increases by raising the reduction. Hardness Values of welded specimens were higher than those of original material especially near the interface and a more uniform hardness profile was obtained after rolling process.

  10. The effect of post-weld heat treatment on the microstructure and notched tensile fracture of Ti–15V–3Cr–3Al–3Sn to Ti–6Al–4V dissimilar laser welds

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, C.T.; Shiue, R.K. [Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan, ROC (China); Huang, R.-T. [Institute of Materials Engineering, National Taiwan Ocean University, Keelung 202, Taiwan, ROC (China); Tsay, L.W., E-mail: b0186@mail.ntou.edu.tw [Institute of Materials Engineering, National Taiwan Ocean University, Keelung 202, Taiwan, ROC (China)

    2016-01-20

    A CO{sub 2} laser was applied for dissimilar welding of Ti–15V–3Cr–3Al–3Sn (Ti–15–3) to Ti–6Al–4V (Ti–6–4) alloys. The microstructures and notched tensile strength (NTS) of the dissimilar welds were investigated in the as-welded and post-weld heat treatment (PWHT) conditions, and the results were compared with Ti–6–4 and Ti–15–3 homogeneous laser welds with the same PWHT. The results indicated that predominant α″ with a few α and β phases was formed in the as-welded fusion zone (FZ). Furthermore, the FZ hardness was susceptible to the PWHT and showed a plateau for the specimens aged in the temperature range from 426 to 482 °C/4 h. In comparison with the homogeneous Ti–15–3 weld under the same PWHT conditions, the dilution of Ti–15–3 with Ti–6–4 caused a slight increase in the Al equivalent (Al{sub EQ}) of the FZ, resulting in a further rise in FZ hardness. With the PWHT at/below 538 °C, the dissimilar welds were associated with low NTS or high notch brittleness.

  11. DETECTION AND ANALYSIS OF WELD POOL SHAPE FOR CO2 SHORT CIRCUITING ARC WELDING

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A general industrial CCD(ICCD) camera is redesigned to detect the weld pool without arc at the period of short circuiting,so that the interference of arc and spatter during CO2 short circuiting arc welding is eliminated. Through the analysis of weld pool image, both size parameters (such as weld pool area A, weld pool length L1, L2 and weld pool breadth b) and contour parameters (bi which describe the curves of weld pool boundany) ,which could indicate the shape features of weld pool, had been defined to express weld pool information quantitatively. The investigation of the relationships between weld pool shape parameters and welding process parameters may be beneficial to the quality control of CO2 welding.

  12. Weld Metal Cooling Rate Indicator System.

    Science.gov (United States)

    rate of change of weld temperature at the predetermined weld temperature. A range of...provided so that the rate of change of weld temperatures at the predetermined weld temperature can be compared with this range. A device is then provided...which is responsive to the comparing information for indicating whether the rate of change of weld temperature is within, above, or below the range

  13. Corrosion Properties of Laser Welded Stainless Steel

    DEFF Research Database (Denmark)

    Weldingh, Jakob; Olsen, Flemmming Ove

    1997-01-01

    In this paper the corrosion properties of laser welded AISI 316L stainless steel are examined. A number of different welds has been performed to test the influence of the weld parameters of the resulting corrosion properties. It has been chosen to use the potential independent critical pitting...... temperature (CPT) test as corrosion test. The following welding parameters are varied: Welding speed, lsser power, focus point position and laser operation mode (CW or pulsed)....

  14. Versatile Friction Stir Welding/Friction Plug Welding System

    Science.gov (United States)

    Carter, Robert

    2006-01-01

    A proposed system of tooling, machinery, and control equipment would be capable of performing any of several friction stir welding (FSW) and friction plug welding (FPW) operations. These operations would include the following: Basic FSW; FSW with automated manipulation of the length of the pin tool in real time [the so-called auto-adjustable pin-tool (APT) capability]; Self-reacting FSW (SRFSW); SR-FSW with APT capability and/or real-time adjustment of the distance between the front and back shoulders; and Friction plug welding (FPW) [more specifically, friction push plug welding] or friction pull plug welding (FPPW) to close out the keyhole of, or to repair, an FSW or SR-FSW weld. Prior FSW and FPW systems have been capable of performing one or two of these operations, but none has thus far been capable of performing all of them. The proposed system would include a common tool that would have APT capability for both basic FSW and SR-FSW. Such a tool was described in Tool for Two Types of Friction Stir Welding (MFS- 31647-1), NASA Tech Briefs, Vol. 30, No. 10 (October 2006), page 70. Going beyond what was reported in the cited previous article, the common tool could be used in conjunction with a plug welding head to perform FPW or FPPW. Alternatively, the plug welding head could be integrated, along with the common tool, into a FSW head that would be capable of all of the aforementioned FSW and FPW operations. Any FSW or FPW operation could be performed under any combination of position and/or force control.

  15. Study of gas tungsten arc welding procedures for tantalum alloy T-111 (Ta-8 W-2Hf) plate

    Science.gov (United States)

    Gold, R. E.; Kesterson, R. L.

    1973-01-01

    Methods of eliminating or reducing underbread cracking in multipass GTA welds in thick T-111 plate were studied. Single V butt welds prepared using experimental filler metal compositions and standard weld procedures resulted in only moderate success in reducing underbread cracking. Subsequent procedural changes incorporating manual welding, slower weld speeds, and three or fewer fill passes resulted in crack-free single V welds only when the filler metal was free of hafnium. The double V joint design with successive fill passes on opposite sides of the joint produced excellent welds. The quality of each weld was determined metallographically since the cracking, when present, was very slight and undetectable using standard NDT techniques. Tensile and bend tests were performed on selected weldments. The inherent filler metal strength and the joint geometry determined the strength of the weldment. Hardness and electron beam microprobe traverses were made on selected specimens with the result that significant filler metal-base metal dilution as well as hafnium segregation was detected. A tentative explanation of T-111 plate underbread cracking is presented based on the intrinsic effects of hafnium in the weldment.

  16. Changes in Precipitate Distributions and the Microstructural Evolution of P24/P91 Dissimilar Metal Welds During PWHT

    Science.gov (United States)

    Dawson, Karl E.; Tatlock, Gordon J.; Chi, Kuangnan; Barnard, Peter

    2013-11-01

    The effect of post-weld heat treatments (PWHTs) on the evolution of precipitate phases in dissimilar metal welds made between 9 pct Cr P91 alloy and 2.25 pct Cr T/P24-type weld metal has been investigated. Sections of multi-pass fusion welds were analyzed in their as welded condition and after PWHTs of 2 and 8 hour duration at 1003 K (730 °C). Thin foil specimens and carbon extraction replicas have been examined in transmission electron microscopes in order to identify precipitate phases and substantiate their distributions in close proximity to the fusion line. The findings of these studies confirm that a carbon-depleted region develops in the lower alloyed weld material, adjacent to the weld interface, during thermal processing. A corresponding carbon enriched region is formed, simultaneously, in the coarse grain heat affected zone of the P91 parent alloy. It has been demonstrated that carbon depletion from the weld alloy results in the dissolution of M7C3 and M23C6 chromium carbides. However, micro-alloying additions of vanadium and niobium which are made to both the P24 and P91 alloys facilitate the precipitation of stable, nano-scale, MX carbonitride particles. This work demonstrates that these particles, which are of key importance to the strength of ferritic creep resistant alloys, are retained in carbon-depleted regions. The microstructural stability which is conferred by their retention means that the pernicious effects of recrystallization are largely avoided.

  17. Rheology of welding: Field constraints

    Science.gov (United States)

    Russell, K.; Quane, S.

    2003-04-01

    Pyroclastic deposits emplaced at high temperature and having sufficient thickness become welded via sintering, compaction and flattening of hot glassy particles. The welding process is attended by pronounced changes in the physical properties of the deposit and welding intensity can be tracked by measuring the density, porosity, fabric or strength of samples. Ultimately, the intensity of welding reflects the aggregate effects of load and residence time at temperatures above the glass transition temperature (Tg). This results in welding intensity varying with stratigraphic depth; vertical sections through welded ignimbrite deposits commonly show maximum (e.g., density) or minimum (porosity) values in physical properties in the lower half (30--40% above the base) of the unit. Here we explore the extent to which these data, serving as proxies for strain, can be used constrain the rheological properties of the pyroclastic deposit during the welding process. Our data include measurements of density, porosity, fabric and rock strength as a function of stratigraphic position for 4 sections through the Bandelier tuff, New Mexico. These profiles record changes in physical properties and, thus, map the cumulative strain associated with welding as a function of depth (load). We have used simple conductive heat transfer models to estimate cooling curves for each sample. Essentially, these curves provide the residence time within the "welding window" for each sample. The curves are dependent on sample position, thickness of ignimbrite, emplacement temperature and the glass transition temperature of the material. The unknowns in the problem are a number of physical constants in a generalized power-law relationship between strain-rate (ɛ') and stress (σ) for steady-state creep at constant load: ɛ' = A σ^n e[-Q/R T]. Specifically, we adopt an inverse-model approach whereby the observations on the natural material are used to constrain the pre-exponential constant (A), stress

  18. Mechanical properties of full austenitic welding joint at cryogenic temperature for the ITER toroidal field coil structure

    Energy Technology Data Exchange (ETDEWEB)

    Iguchi, M., E-mail: iguchi.masahide@jaea.go.jp [Japan Atomic Energy Agency, ITER Superconducting Magnet Technology Group, 801-1 Mukoyama, Naka, Ibaraki 311-0193 Japan (Japan); Saito, T.; Kawano, K.; Chida, Y.; Nakajima, H. [Japan Atomic Energy Agency, ITER Superconducting Magnet Technology Group, 801-1 Mukoyama, Naka, Ibaraki 311-0193 Japan (Japan); Ogawa, T.; Katayama, Y.; Ogata, H.; Minemura, T. [Toshiba Cooperation, Power Systems Company, 2-4, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 2300-0045 (Japan); Tokai, D.; Niimi, K. [Kawasaki Heavy Industries, LTD., Plant and Infrastructure Company, Production Center, 8, Niijima, Harima-cho, Kako-gun, Hyogo 675-0180 (Japan)

    2013-10-15

    Highlights: • No significant distribution of tensile strengths at 4 K, 77 K and room temperature along welding thickness of 200 mm manufactured by one side narrow gap TIG welding with FMYJJ1. • Tensile strengths at cryogenic temperature of welded joint are increased with increasing of C + N contents of base material. • In the case that welded joint is manufactured by combination of different base materials, strength at 4 K of welded joints are below strength of base material having higher C + N contents. -- Abstract: ITER toroidal field coil (TFC) structures are large welding structures composed of coil case and support structures made of heavy thick high strength and high toughness stainless steels. Japan Atomic Energy Agency plans to apply narrow gap Tungsten Inert Gas (TIG) welding with FMYJJ1 (0.03C–10Mn–12Cr–14Ni–5Mo–0.13N) which is full austenitic stainless filler material. In order to evaluate effect of base material thickness and combinations of base material on tensile properties, tensile tests were performed at room temperature, 77 K and 4 K by using tensile specimens taken from 200 mm thickness welded joints of two combinations of base materials and 40 mm thickness welded joints of four combinations of base materials. As the results, it was confirmed that there were no large distribution of yield and tensile strength along the thickness of welded joints of 200 mm thickness and yield and tensile strengths of welded joints were decreased with decreasing of C + N contents of base material.

  19. Study of Gasdynamic Effect Upon the Weld Geometry When Concumable Electrode Welding

    Science.gov (United States)

    Chinakhov, D. A.; Grigorieva, E. G.; Mayorova, E. I.

    2016-04-01

    The paper considers the ways of weld geometry controlling when consumable electrode welding under single-jet and double-jet gas shielding. The authors provide comparative results of experimental studies on the effects of shielding gas supply upon the weld geometry in weld joints produced from construction carbon steel 45. It has been established that gas-dynamic effect of the shielding gas has a significant impact upon shaping and weld geometry when consumable electrode welding under double-jet gas shielding.

  20. Creep properties and simulation of weld repaired low alloy heat resistant CrMo and Mo steels at 540 deg C. Sub project 1 - Ex-serviced parent metal and virgin weld metals

    Energy Technology Data Exchange (ETDEWEB)

    Rui Wu; Storesund, Jan; Borggreen, Kjeld; Weilin Zang

    2006-10-15

    Many existing power generating and process plants, where low alloy heat resistant CrMo(V) steels are extensively used for critical components, have exceeded their design lifetime of usually 100,000 hours. Assessment of residual lifetime and extension of economic life by weld repair have become increasingly important and attractive. This project aims at i) performing weld repair and determining the degree of mismatching, ii) evaluating the creep properties of weld repairs, iii) analysing creep behaviour of weld repair and providing necessary data for further reliable simulations of weld repair creep behaviour in long term service, and iv), simulating and assessing lifetime and creep damage evolution of weld repair. Weld repair using 10 CrMo 9 10, 13 CrMo 4 4 and 15 Mo 3 consumables has been carried out in a service-exposed 10 CrMo 9 10 pipe. Creep specimens have been extracted from the service-exposed 10 CrMo 9 10 parent metal (PM), from the virgin 10 CrMo 9 10 weld metal (WM), from the virgin 13 CrMo 4 4 WM as well as from the virgin 15 Mo 3 WM. Iso-thermal uniaxial creep tests have been performed at 540 deg C in air. Pre- and post-metallography are carried out on the selected samples. FEM simulations using obtained creep data are executed. Pre-test metallography shows normal and acceptable weld repairs at given welding conditions. Creep tests demonstrate that the virgin 10 CrMo 9 10, 13 CrMo 4 4 and 15 Mo 3 WMs have apparently longer creep lifetime than the service-exposed CrMo 9 10 PM at higher stresses than 110 MPa. Among the weld metals, the longest creep lifetime is found in 10 CrMo 9 10. Higher creep strength and lower creep strain rate in the weld metals indicate an overmatch weld. At 95 MPa, however, lifetime of 13 CrMo 4 4 WM is surprisingly short (factors which may shorten lifetime are discussed and one more test will start to verify creep strength at low stress) and tests are still running for other two weld metals. More results regarding low stress

  1. A study of weld quality in ultrasonic spot welding of similar and dissimilar metals

    Science.gov (United States)

    Al-Sarraf, Z.; Lucas, M.

    2012-08-01

    Several difficulties are faced in joining thinner sheets of similar and dissimilar materials from fusion welding processes such as resistance welding and laser welding. Ultrasonic metal welding overcomes many of these difficulties by using high frequency vibration and applied pressure to create a solid-state weld. Ultrasonic metal welding is an effective technique in joining small components, such as in wire bonding, but is also capable of joining thicker sheet, depending on the control of welding conditions. This study presents the design, characterisation and test of a lateral-drive ultrasonic metal welding device. The ultrasonic welding horn is modelled using finite element analysis and its vibration behaviour is characterised experimentally to ensure ultrasonic energy is delivered to the weld coupon. The welding stack and fixtures are then designed and mounted on a test machine to allow a series of experiments to be conducted for various welding and ultrasonic parameters. Weld strength is subsequently analysed using tensile-shear tests. Control of the vibration amplitude profile through the weld cycle is used to enhance weld strength and quality, providing an opportunity to reduce part marking. Optical microscopic examination and scanning electron microscopy (SEM) were employed to investigate the weld quality. The results show how the weld quality is particularly sensitive to the combination of clamping force and vibration amplitude of the welding tip.

  2. A method of initial welding position guiding for arc welding robot based on visual servo control

    Institute of Scientific and Technical Information of China (English)

    郭振民; 陈善本; 邱涛; 吴林

    2003-01-01

    In order to solve the visual guiding task of initial welding position for arc welding robot, this paper presents a practice-prone image-based visual servo control strategy without calibration, and we perform validating experiments on a nine-DOF arc welding robot system. Experimental results illustrate presented method has the function to fulfill the task of welding robot initial positioning with certain anti-jamming ability. This method provides a basis for guiding welding gun to initial welding pose with real typical seam's image properties to replace flag block properties, and is a significant exploit to realize visual guiding of initial welding position and seam tracing in robot welding system.

  3. Laser welding of fused quartz

    Science.gov (United States)

    Piltch, Martin S.; Carpenter, Robert W.; Archer, III, McIlwaine

    2003-06-10

    Refractory materials, such as fused quartz plates and rods are welded using a heat source, such as a high power continuous wave carbon dioxide laser. The radiation is optimized through a process of varying the power, the focus, and the feed rates of the laser such that full penetration welds may be accomplished. The process of optimization varies the characteristic wavelengths of the laser until the radiation is almost completely absorbed by the refractory material, thereby leading to a very rapid heating of the material to the melting point. This optimization naturally occurs when a carbon dioxide laser is used to weld quartz. As such this method of quartz welding creates a minimum sized heat-affected zone. Furthermore, the welding apparatus and process requires a ventilation system to carry away the silicon oxides that are produced during the welding process to avoid the deposition of the silicon oxides on the surface of the quartz plates or the contamination of the welds with the silicon oxides.

  4. 10,170 flawless welds

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    The welding of tubes containing the principal current-carrying busbars in the LHC magnets was one of the main activities of the SMACC project. After a year of preparation and another of intense activity in the tunnel, the last weld was completed on Wednesday 14 May. Over 10,170 welds have been inspected and not a single fault has been found.    The welder (above) creates the weld using an orbital welding machine (below) specifically designed for CERN. Each of the eight sectors of the LHC contains around 210 interconnects between the superconducting magnets. Consolidating these interconnections was the SMACC project’s primary objective. One of the last jobs before closing the interconnects is the welding of the M lines: each has a 104 mm diameter and a radial clearance of just 45 mm. In total: 10,170 welds carried out in a single year of activities. A true challenge, which was carried out by a team of 30 highly specialised welders, working under the supervision o...

  5. Pulse shaping effects on weld porosity in laser beam spot welds : contrast of long- & short- pulse welds.

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, Chad M. (Honeywell FM& T, Kansas City, MO); Perricone, Matthew J. (R.J. Lee Group, Inc., Monroeville, PA); Faraone, Kevin M. (BWX Technologies, Inc., Lynchburg, VA); Norris, Jerome T.

    2007-10-01

    Weld porosity is being investigated for long-pulse spot welds produced by high power continuous output lasers. Short-pulse spot welds (made with a pulsed laser system) are also being studied but to a much small extent. Given that weld area of a spot weld is commensurate with weld strength, the loss of weld area due to an undefined or unexpected pore results in undefined or unexpected loss in strength. For this reason, a better understanding of spot weld porosity is sought. Long-pulse spot welds are defined and limited by the slow shutter speed of most high output power continuous lasers. Continuous lasers typically ramp up to a simmer power before reaching the high power needed to produce the desired weld. A post-pulse ramp down time is usually present as well. The result is a pulse length tenths of a second long as oppose to the typical millisecond regime of the short-pulse pulsed laser. This study will employ a Lumonics JK802 Nd:YAG laser with Super Modulation pulse shaping capability and a Lasag SLS C16 40 W pulsed Nd:YAG laser. Pulse shaping will include square wave modulation of various peak powers for long-pulse welds and square (or top hat) and constant ramp down pulses for short-pulse welds. Characterization of weld porosity will be performed for both pulse welding methods.

  6. Residual stresses in welded plates

    Science.gov (United States)

    Bernstein, Edward L.

    1994-01-01

    The purpose of this project was to develop a simple model which could be used to study residual stress. The mechanism that results in residual stresses in the welding process starts with the deposition of molten weld metal which heats the immediately adjacent material. After solidification of weld material, normal thermal shrinkage is resisted by the adjacent, cooler material. When the thermal strain exceeds the elastic strain corresponding to the yield point stress, the stress level is limited by this value, which decreases with increasing temperature. Cooling then causes elastic unloading which is restrained by the adjoining material. Permanent plastic strain occurs, and tension is caused in the region immediately adjacent to the weld material. Compression arises in the metal farther from the weld in order to maintain overall static equilibrium. Subsequent repair welds may add to the level of residual stresses. The level of residual stress is related to the onset of fracture during welding. Thus, it is of great importance to be able to predict the level of residual stresses remaining after a weld procedure, and to determine the factors, such as weld speed, temperature, direction, and number of passes, which may affect the magnitude of remaining residual stress. It was hoped to use traditional analytical modeling techniques so that it would be easier to comprehend the effect of these variables on the resulting stress. This approach was chosen in place of finite element methods so as to facilitate the understanding of the physical processes. The accuracy of the results was checked with some existing experimental studies giving residual stress levels found from x-ray diffraction measurements.

  7. Microstructure and Properties of 6061 Aluminium Alloy Welded Joint by Ultrasonic Welding%6061铝合金超声波焊接接头组织与性能研究

    Institute of Scientific and Technical Information of China (English)

    熊志林; 朱政强; 吴宗辉; 王小龙

    2011-01-01

    采用超声波焊接方法对0.3mm厚的6061铝合金进行焊接,焊后利用光学显微镜和扫描电镜对焊接接头组织和表面形貌进行分析,重点研究了试样表面处理、焊接时间及焊接压力对焊后铝合金剥离强度和硬度的影响.结果表明:在焊接时间120ms,焊接压力17.5 MPa下,表面加乙醇处理的试样剥离力最高达到136.478N,硬度53.9HV;同时,焊缝平整规则,界面结合良好.%6061 aluminum alloy with the thickness of 0.3 mm was welded by ultrasonic welding. The microstructure and surface morphology of the ultrasonic welded joint were analyzed. The variation of the peeling loads and hardness of welding specimens under the state of aluminum surface treatment,welding time and welding pressure were studied. The experimental results indicate that the peeling loads is up to 136.478 N and hardness is up to S3.9 HV under the welding time 120 ms,welding pressure 17.S Mpa and the surface of specimen in ethanol. Meanwhile, the weld is flat, the interface bonding is good.

  8. Laser welding and post weld treatment of modified 9Cr-1MoVNb steel.

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z. (Nuclear Engineering Division)

    2012-04-03

    Laser welding and post weld laser treatment of modified 9Cr-1MoVNb steels (Grade P91) were performed in this preliminary study to investigate the feasibility of using laser welding process as a potential alternative to arc welding methods for solving the Type IV cracking problem in P91 steel welds. The mechanical and metallurgical testing of the pulsed Nd:YAG laser-welded samples shows the following conclusions: (1) both bead-on-plate and circumferential butt welds made by a pulsed Nd:YAG laser show good welds that are free of microcracks and porosity. The narrow heat affected zone has a homogeneous grain structure without conventional soft hardness zone where the Type IV cracking occurs in conventional arc welds. (2) The laser weld tests also show that the same laser welder has the potential to be used as a multi-function tool for weld surface remelting, glazing or post weld tempering to reduce the weld surface defects and to increase the cracking resistance and toughness of the welds. (3) The Vicker hardness of laser welds in the weld and heat affected zone was 420-500 HV with peak hardness in the HAZ compared to 240 HV of base metal. Post weld laser treatment was able to slightly reduce the peak hardness and smooth the hardness profile, but failed to bring the hardness down to below 300 HV due to insufficient time at temperature and too fast cooling rate after the time. Though optimal hardness of weld made by laser is to be determined for best weld strength, methods to achieve the post weld laser treatment temperature, time at the temperature and slow cooling rate need to be developed. (4) Mechanical testing of the laser weld and post weld laser treated samples need to be performed to evaluate the effects of laser post treatments such as surface remelting, glazing, re-hardening, or tempering on the strength of the welds.

  9. Underwater explosive welding of tungsten to reduced-activation ferritic steel F82H

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Daichi [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Kasada, Ryuta, E-mail: r-kasada@iae.kyoto-u.ac.jp [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Konishi, Satoshi [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Morizono, Yasuhiro [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Hokamoto, Kazuyuki [Institute of Pulsed Power Science, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan)

    2014-10-15

    Highlights: • The underwater explosive welding was successfully applied in the joining of tungsten to F82H reduced activation ferritic steel. • Microstructure of the interface showed the formation of a wave-like interface with a thin mixed layer of tungsten and F82H. • Nanoindentation hardness results exhibited a gradual change away from the welded interface without hardened layer. • Small punch tests on the welded specimens resulted in the cracking at a center of tungsten followed by the interfacial cracking. - Abstract: The present study reports the underwater explosive welding of commercially pure tungsten onto the surface of a reduced-activation ferritic steel F82H plate. Cross-sectional observation revealed the formation of a wave-like interface, consisting of a thin mixed layer of W and F82H. The results of nanoindentation hardness testing identified a gradual progressive change in the interface, with no hardened or brittle layer being observed. Small punch tests on the welded specimens resulted in cracking at the center of the tungsten, followed by crack propagation toward both the tungsten surface and the tungsten/steel interface.

  10. Novel Process Revolutionizes Welding Industry

    Science.gov (United States)

    2008-01-01

    Glenn Research Center, Delphi Corporation, and the Michigan Research Institute entered into a research project to study the use of Deformation Resistance Welding (DRW) in the construction and repair of stationary structures with multiple geometries and dissimilar materials, such as those NASA might use on the Moon or Mars. Traditional welding technologies are burdened by significant business and engineering challenges, including high costs of equipment and labor, heat-affected zones, limited automation, and inconsistent quality. DRW addresses each of those issues, while drastically reducing welding, manufacturing, and maintenance costs.

  11. Development of Welding Procedures for NPP Dissimilar Metal Weld

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jang Wook; Cho, Hong Seok; Lee, Dong Min; Park, Yu Deog; Choi, Sang Hoon [Korea Plant Service and Engineering Co., Seongnam (Korea, Republic of)

    2008-05-15

    Nuclear primary system consists of various materials according to the function. Recently, concern about the integrity on Dissimilar Metal Weld (DMW) which was made of inconel material such as alloy 600/82/182 has arisen from industry. Leak from hot leg nozzle weld at V.C Summer and axial cracks in hot leg nozzle welds at Ringhals 3 and 4 were took placed at the DMW zone, which is major degradation mechanism known as Primary Water Stress Corrosion Cracking (PWSCC). In order to ensure operational ability of nuclear power plants, it is necessary to obtain measures against unexpected risks. KPS has developed the DMW technology, Narrow Groove Welding (NGW) system and field implementation procedures for alloy 600 since March 2005.

  12. MACHINING TEST SPECIMENS FROM HARVESTED ZION RPV SEGMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Nanstad, Randy K [ORNL; Rosseel, Thomas M [ORNL; Sokolov, Mikhail A [ORNL

    2015-01-01

    The decommissioning of the Zion Nuclear Generating Station (NGS) in Zion, Illinois, presents a special and timely opportunity for developing a better understanding of materials degradation and other issues associated with extending the lifetime of existing nuclear power plants (NPPs) beyond 60 years of service. In support of extended service and current operations of the US nuclear reactor fleet, the Oak Ridge National Laboratory (ORNL), through the Department of Energy (DOE), Light Water Reactor Sustainability (LWRS) Program, is coordinating and contracting with Zion Solutions, LLC, a subsidiary of Energy Solutions, an international nuclear services company, the selective procurement of materials, structures, components, and other items of interest from the decommissioned reactors. In this paper, we will discuss the acquisition of segments of the Zion Unit 2 Reactor Pressure Vessel (RPV), cutting these segments into blocks from the beltline and upper vertical welds and plate material and machining those blocks into mechanical (Charpy, compact tension, and tensile) test specimens and coupons for microstructural (TEM, SEM, APT, SANS and nano indention) characterization. Access to service-irradiated RPV welds and plate sections will allow through wall attenuation studies to be performed, which will be used to assess current radiation damage models [1].

  13. Tensile properties of a titanium modified austenitic stainless steel and the weld joints after neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, K.; Ioka, I.; Jitsukawa, S.; Hamada, A.; Hishinuma, A. [and others

    1996-10-01

    Tensile specimens of a titanium modified austenitic stainless steel and its weldments fabricated with Tungsten Inert Gas (TIG) and Electron Beam (EB) welding techniques were irradiated to a peak dose of 19 dpa and a peak helium level of 250 appm in the temperature range between 200 and 400{degrees}C in spectrally tailored capsules in the Oak Ridge Research Reactor (ORR) and the High Flux Isotope Reactor (HFIR). The He/dpa ratio of about 13 appm/dpa is similar to the typical helium/dpa ratio of a fusion reactor environment. The tensile tests were carried out at the irradiation temperature in vacuum. The irradiation caused an increase in yield stress to levels between 670 and 800 MPa depending on the irradiation temperature. Total elongation was reduced to less than 10%, however the specimens failed in a ductile manner. The results were compared with those of the specimens irradiated using irradiation capsules producing larger amount of He. Although the He/dpa ratio affected the microstructural change, the impact on the post irradiation tensile behavior was rather small for not only base metal specimens but also for the weld joint and the weld metal specimens.

  14. Materials participation in welded joints manufacturing

    Science.gov (United States)

    Ghenghea, L. D.

    2016-08-01

    Management of materials dilution to form a joint with higher features asked by complex metallic structures is a problem that took attention and efforts of welding processes researchers and this communication will give a little contribution presenting some scientific and experimental results of dilution processes studied by Welding Research Group from Iasi, Romania, TCM Department. Liquid state welding processes have a strong dependence related to dilution of base and filler materials, the most important are for automatic joining using welding. The paper presents a review of some scientific works already published and their contributions, results of dilution coefficient evaluation using weighing, graphics and software applied for shielded metal arc welding process. Paper results could be used for welders’ qualification, welding procedure specification and other welding processes researchers’ activities. The results of Welding Research Group from Iasi, Romania, TCM Department, show dilution coefficient values between 20-30 % of base material and 70-80 % of filler material for studied welding process.

  15. Effect of Welding Parameters on Dilution and Weld Bead Geometry in Cladding

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effect of pulsed gas metal arc welding (GMAW) variables on the dilution and weld bead geometry in cladding X65 pipeline steel with 316L stainless steel was studied. Using a full factorial method, a series of experiments were carried out to know the effect of wire feed rate, welding speed, distance between gas nozzle and plate, and the vertical angle of welding on dilution and weld bead geometry. The findings indicate that the dilution of weld metal and its dimension i.e. width, height and depth increase with the feed rate, but the contact angle of the bead decreases first and then increases. Meantime, welding speed has an opposite effect except for dilution. There is an interaction effect between welding parameters at the contact angle. The results also show forehand welding or decreasing electrode extension decrease the angle of contact. Finally,a mathematical model is contrived to highlight the relationship between welding variables with dilution and weld bead geometry.

  16. Comparison between hybrid laser-MIG welding and MIG welding for the invar36 alloy

    Science.gov (United States)

    Zhan, Xiaohong; Li, Yubo; Ou, Wenmin; Yu, Fengyi; Chen, Jie; Wei, Yanhong

    2016-11-01

    The invar36 alloy is suitable to produce mold of composite materials structure because it has similar thermal expansion coefficient with composite materials. In the present paper, the MIG welding and laser-MIG hybrid welding methods are compared to get the more appropriate method to overcome the poor weldability of invar36 alloy. According to the analysis of the experimental and simulated results, it has been proved that the Gauss and cone combined heat source model can characterize the laser-MIG hybrid welding heat source well. The total welding time of MIG welding is 8 times that of hybrid laser-MIG welding. The welding material consumption of MIG welding is about 4 times that of hybrid laser-MIG welding. The stress and deformation simulation indicate that the peak value of deformation during MIG welding is 3 times larger than that of hybrid laser-MIG welding.

  17. Acoustic emisson and ultrasonic wave characteristics in TIG-welded 316 stainless steel

    Science.gov (United States)

    Lee, Jin Kyung; Lee, Joon Hyun; Lee, Sang Pill; Son, In Su; Bae, Dong Su

    2014-05-01

    A TIG welded 316 stainless steel materials will have a large impact on the design and the maintenance of invessel components including pipes used in a nuclear power plant, and it is important to clear the dynamic behavior in the weld part of stainless steel. Therefore, nondestructive techniques of acoustic emission (AE) and ultrasonic wave were applied to investigate the damage behavior of welded stainless steel. The velocity and attenuation ratio of the ultrasonic wave at each zone were measured, and a 10 MHz sensor was used. We investigated the relationship between dynamic behavior and AE parameters analysis and derived the optimum parameters to evaluate the damage degree of the specimen. By measuring the velocity and the attenuation of an ultrasonic wave propagating each zone of the welded stainless steel, the relation of the ultrasonic wave and metal structure at the base metal, heat affected zone (HAZ) metal and weld metal is also discussed. The generating tendency of cumulated counts is similar to that of the load curve. The attenuation ratios from the ultrasonic test results were 0.2 dB/mm at the base zone, and 0.52 dB/mm and 0.61 dB/mm at the HAZ zone and weld zone, respectively.

  18. Chemical composition effect on VVER-1000 RPV weld metal thermal aging

    Science.gov (United States)

    Gurovich, B. A.; Chernobaeva, A. A.; Erak, D. Yu; Kuleshova, E. A.; Zhurko, D. A.; Papina, V. B.; Skundin, M. A.; Maltsev, D. A.

    2015-10-01

    Temperature and fast neutron flux simultaneously affect the material of welded joints of reactor pressure vessels under irradiation. Understanding thermal aging effects on the weld metal allows for an explanation of the mechanisms that govern an increase in the ductile-to-brittle transition temperature of the reactor pressure vessel materials under long term irradiation at operation temperature. This paper reports on new results and reassessment of the VVER-1000 weld metal surveillance specimen database performed at the National Research Center "Kurchatov Institute". The current database of VVER-1000 weld metal thermal aging at 310-320 °C includes 50 transition temperature values with the maximum holding time of 208,896 h. The updated database completed with the information on intergranular fracture shear and phosphorous content in the grain boundaries has allowed us to propose a new mechanism of VVER-1000 weld materials thermal aging at 310-320 °C and develop models of ductile-to-brittle transition temperature shift for VVER-1000 weld metal during a long-term exposure at 310-320 °C.

  19. Dissimilar Arc Welding of Advanced High-Strength Car-Body Steel Sheets

    Science.gov (United States)

    Russo Spena, P.; D'Aiuto, F.; Matteis, P.; Scavino, G.

    2014-11-01

    A widespread usage of new advanced TWIP steel grades for the fabrication of car-body parts is conditional on the employment of appropriate welding methods, especially if dissimilar welding must be performed with other automotive steel grades. Therefore, the microstructural features and the mechanical response of dissimilar butt weld seams of TWIP and 22MnB5 steel sheets after metal-active-gas arc welding are examined. The microstructural and mechanical characterization of the welded joints was carried out by optical metallography, microhardness and tensile testing, and fractographic examination. The heat-affected zone on the TWIP side was fully austenitic and the only detectable effect was grain coarsening, while on the 22MnB5 side it exhibited newly formed martensite and tempered martensite. The welded tensile specimens exhibited a much larger deformation on the TWIP steel side than on the 22MnB5. The fracture generally occurred at the interface between the fusion zone and the heat-affected zones, with the fractures surfaces being predominantly ductile. The ultimate tensile strength of the butt joints was about 25% lower than that of the TWIP steel.

  20. Creep behaviour and microstructural evolution in P23/P91 dissimilar welds

    Energy Technology Data Exchange (ETDEWEB)

    Vodarek, V. [Technical Univ. of Ostrava (Czech Republic); Kubon, Z.; Strilkova, L. [MATERIALS AND METALLURGICAL RESEARCH Ltd., Ostrava (Czech Republic); Hainsworth, S.V. [Leicester Univ. (United Kingdom). Dept. of Engineering

    2010-07-01

    The structural integrity of welded components operated at elevated temperatures is of key importance in power plant applications. Long-term creep exposure of dissimilar welds is accompanied by redistribution of interstitial elements which strongly affects microstructural evolution in the vicinity of the fusion zone between low and high alloy materials. This paper summarises results of studies on creep rupture properties and minor phase evolution in the P23/P71 heterogeneous welds duing creep exposure at 500, 550 and 600 C for durations exceeding 60 000 hours. The composition of filler material in Weld A corresponded to that of P91 steel, whilst for Weld B the low alloy filler material of P23 type composition was used. Results of creep rupture tests on the cross weld specimens are close to, or slightly below, the lower limit of the {+-}20% scatter band around the standardized curve for creep strength of the P23 steel. Experimental data on microstructural evolution have been compared with results of thermodynamic and kinetic simulations. The predicted minor phase evolution close to the P23/P91 interface was confirmed by microstructural investigations. Some differences between calculations and experimental studies were found for the P23 steel. It was demonstrated that undissolved fine MX particles in the partly decarburized zone of the P23 (WM23) steel significantly delayed recrystallization of the bainitic matrix. (orig.)

  1. Microstructure and mechanical properties of laser welded DP600 steel joints

    Energy Technology Data Exchange (ETDEWEB)

    Farabi, N. [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada); Chen, D.L., E-mail: dchen@ryerson.ca [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada); Li, J.; Zhou, Y. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Dong, S.J. [School of Mechanical Engineering, Hubei University of Technology, Wuhan, Hubei (China)

    2010-02-15

    To reduce fuel consumption and greenhouse gas emissions, dual phase (DP) steels have been considered for automotive applications due to their higher tensile strength, better initial work hardening along with larger elongation compared to conventional grade of steels. In such applications welding and joining have to be involved, which would lead to a localized alteration of materials and create potential safety and reliability issues under cyclic loading. The aim of this investigation was to evaluate microstructural change after laser welding and its effect on the tensile and fatigue properties in DP600 steel. The welding resulted in a significant increase of hardness in the fusion zone, but also the formation of a soft zone in the outer heat-affected zone (HAZ). While the ductility decreased after welding, the yield strength increased and the ultimate tensile strength remained almost unchanged. Fatigue life at higher stress amplitudes was almost the same between the base metal and welded joints despite slightly lower fatigue limit after welding. Tensile fracture and fatigue failure at higher stress amplitudes occurred at the outer HAZ. Fatigue crack initiation was observed to occur from the specimen surface and crack propagation was characterized by the characteristic mechanism of striation formation. Dimples and deformation bands were observed in the fast propagation area.

  2. Friction Stir Welding Technology: Adapting NASA's Retractable Pin Tool

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    In late 1991, The Welding Institute (TWI), a British research and technology organization, invented and patented a welding process named Friction Stir Welding (FSW). Friction Stir Welding is a highly significant advancement in aluminum welding technology that can produce stronger, lighter, and more efficient welds than any previous process.

  3. Research on image segmentation of weld seam of oil derrick welded by arc welding robot

    Institute of Scientific and Technical Information of China (English)

    Cai Guangyu; Cui Shilin; Wu Changlin

    2009-01-01

    This paper puts forward a new method of PCNN (pulse-coupled neural networks) image segmentation, in which the binary matrix of the ignition frequency matrix is employed, for the first time, to act as the final result of image segmentation. It gives the principles of PCNN parameter selection under the guidance of this process. The new method reduces the dependence of PCNN on parameters, improves the effect of image segmentation, and produces good results after being applied to image recognition of weld seam of oil derrick welded by arc welding robot.

  4. Pitting corrosion behaviour of built-up welds - Effects of welding layers and tarnish; Lochkorrosionsverhalten von Auftragschweissungen - Schweisslagen- und Oberflaecheneffekte

    Energy Technology Data Exchange (ETDEWEB)

    Heyn, A.; Schilling, K.; Boese, E.; Spieler, S.; Altendorf, S. [Otto-von-Guericke-Universitaet Magdeburg, IWW, PF 4120, 39016 Magdeburg (Germany); Burkert, A. [BAM, Berlin, Fachgruppe VII.3, Unter den Eichen 87, 12205 Berlin (Germany); Schultze, S. [LMPA Sachsen-Anhalt, Grosse Steinernetischstrasse 4, 39104 Magdeburg (Germany)

    2003-12-01

    The pitting corrosion resistance of nickel based deposition welds on a superduplex steel made by active-gas metal pulsed-arc welding was studied. Therefore the determination of the CPT (Critical Pitting Temperature) should be carried out corresponding to ASTM G 48 C. However an unexpectedly low resistance of the built-up welds also at multilayer order was noticed. After visual assessment of the examined specimens a significant effect of the surface condition was assumed. Because the CPT determination according to ASTM does not allow any statement about the corrosion process, this method was not suitable to characterize the corrosion system. For this reason a new method was applied to clarify the causes of the low corrosion resistance. This method determines the CPT with the help of the electrochemical current noise under the same conditions demanded in ASTM G 48 C. The temperature is increased continuously and the characteristic parameters of the system are recorded and evaluated objectively within short time. So it was possible to see the influence of the surface condition on the pitting corrosion behaviour of the examined specimens. The required parameters to the post-processing of the deposition welds were determined. The comparison of the results show that the surface tarnish formed after the shielded arc welding process influences the pitting corrosion resistance negatively. After its elimination the CPT could be determined in dependence of the welding layers. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [German] Zur vergleichenden Einschaetzung der Lochkorrosionsbestaendigkeit von verschiedenen, mehrlagigen MAGp-auftraggeschweissten Nickelbasis-Schweissguetern auf einem Superduplexstahl wurden kritische Lochkorrosionstemperaturen (critical pitting temperature, CPT) nach ASTM G 48 C ermittelt. Es zeigte sich eine unerwartet niedrige Bestaendigkeit der Auftragschweissungen, als dessen Ursache ein unguenstiger Oberflaechenzustand angenommen wurde. Da die

  5. Explosive welding of undersea pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Stalker, A.W.

    1978-02-01

    The phenomenon of explosive welding has been known informally for many years. A number of investigations reported the occurerence of solid phase bonds as an incidental effect when using high explosives in association with adjacent metal surfaces and probably the earliest formal record was the observation by Carl in 1944 of a bond between two copper discs in contact with a detonator. In 1957 Philipchuk reported what is now recognized as an explosive weld between aluminium channel sections and a steel die when carrying out explosive forming trials. Since then a great deal of development work has resulted in explosive welding becoming a well established manufacturing technique, particularly in the fields of cladding and the joining of tube/tubeplates. In more recent years the process has been extended to the welding of large diameter line pipe materials.

  6. Welding Development W87 Baseline

    Energy Technology Data Exchange (ETDEWEB)

    A. Newman; G. Gibbs; G. K. Hicken

    1998-11-01

    This report covers the development activities used to qualify the Gas Tungsten Arc (FTA) girth weld and the resistance stem attachments on the W87 Base Line (W87BL). Design of experiments was used throughout the development activities.

  7. Thermomechanical Modelling of Resistance Welding

    DEFF Research Database (Denmark)

    Bay, Niels; Zhang, Wenqi

    2007-01-01

    The present paper describes a generic programme for analysis, optimization and development of resistance spot and projection welding. The programme includes an electrical model determining electric current and voltage distribution as well as heat generation, a thermal model calculating heat...

  8. Welding and Production Metallurgy Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This 6000 square foot facility represents the only welding laboratory of its kind within DA. It is capable of conducting investigations associated with solid state...

  9. Weld bonding of stainless steel

    DEFF Research Database (Denmark)

    Santos, I. O.; Zhang, Wenqi; Goncalves, V.M.

    2004-01-01

    This paper presents a comprehensive theoretical and experimental investigation of the weld bonding process with the purpose of evaluating its relative performance in case of joining stainless steel parts, against alternative solutions based on structural adhesives or conventional spot...

  10. YAG laser welding with surface activating flux

    Institute of Scientific and Technical Information of China (English)

    樊丁; 张瑞华; 田中学; 中田一博; 牛尾诚夫

    2003-01-01

    YAG laser welding with surface activating flux has been investigated, and the influencing factors and mechanism are discussed. The results show that both surface activating flux and surface active element S have fantastic effects on the YAG laser weld shape, that is to obviously increase the weld penetration and D/W ratio in various welding conditions. The mechanism is thought to be the change of weld pool surface tension temperature coefficient, thus, the change of fluid flow pattern in weld pool due to the flux.

  11. Forming of aluminium alloy friction stir welds

    Science.gov (United States)

    Bruni, Carlo

    2016-10-01

    The present paper aims at investigating, through analytical models, numerical models and experiments, the effect of the warm deformation phase, realised with an in temperature upsetting, on the weld previously performed by friction stir lap welding on aluminium alloy blanks. The investigation allows to show the deformation zones after upsetting that determine the homogenisation of the weld section. The analytical model allows to relate the friction factor with the upsetting load. The presence on the weld of not elevated friction factor values determines the deformation and localisation levels very useful for the weld. Such methodology allows to improve the weld itself with the forming phase.

  12. Friction-Stir Welding - Heavy Inclusions in Bi-metallic welds of Al 2219/2195

    Science.gov (United States)

    Rietz, Ward W., Jr.

    2008-01-01

    Heavy Inclusions (HI) were detected for the first time by radiographic examination in aluminum alloy 2219forging/2195plate (advancing/retreating side) Friction Sir Welds (FSW) for the Space Shuttle External Tank (ET) Program. Radiographic HI indications appear as either small (approx.0.005"-0.025") individual particles or clusters of small particles. Initial work was performed to verify that the HI was not foreign material or caused by FSW pin tool debris. That and subsequent elemental analysis determined that the HI were large agglomerations of Al2Cu (theta phase), which is the strengthening precipitate in Al2219. A literature search on that subject determined that the agglomeration of phase has also been found in Al2219 bead on plate FSW [Ref. 1]. Since this was detected in ET space flight hardware, an investigative study of the effect of agglomerated theta phase particles in FSW Al2219f/2195p was performed. Numerous panels of various lengths were welded per ET weld procedures and radiographically inspected to determine if any HI was detected. Areas that had HI were sampled for room temperature and cyclic cryogenic (-423F) tensile testing and determined no significant adverse affect on mechanical properties when compared to test specimens without HI and historical data. Fracture surface examination using the Scanning Electron Microscope (SEM) revealed smaller phase agglomerations undetectable by radiographic inspection dispersed throughout the Al2219f/2195p FSW. This indicates that phase agglomeration is inherent to the Al2219f/2195p FSW process and only rarely creates agglomerations large enough to be detected by radiography. HI has not been observed in FSW of plate to plate material for either Al2219 or AL2195.

  13. Experimental study on activating welding for aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Huang Yong; Fan Ding

    2005-01-01

    TIG welding and EB welding for aluminum alloy 3003 were carried out to study the effects of activating flux on weld penetration of activating welding for aluminum alloys. SiO2 was used as the activating flux. It is found that, SiO2 can increase the weld penetration and decrease the weld width of FBTIG when the flux gap is small. For A-TIG welding and EB welding with focused mode, the weld penetrations and the weld widths increase simultaneously. SiO2 has little effect on the weld penetration and weld width of EB welding with defocused mode. It is believed that, change of surface tension temperature gradient is not the main mechanism of SiO2 improving weld penetration of activating welding for aluminum alloys.

  14. Quantitative Acoustic Emission Fatigue Crack Characterization in Structural Steel and Weld

    Directory of Open Access Journals (Sweden)

    Adutwum Marfo

    2013-01-01

    Full Text Available The fatigue crack growth characteristics of structural steel and weld connections are analyzed using quantitative acoustic emission (AE technique. This was experimentally investigated by three-point bending testing of specimens under low cycle constant amplitude loading using the wavelet packet analysis. The crack growth sequence, that is, initiation, crack propagation, and fracture, is extracted from their corresponding frequency feature bands, respectively. The results obtained proved to be superior to qualitative AE analysis and the traditional linear elastic fracture mechanics for fatigue crack characterization in structural steel and welds.

  15. Crack-growth behavior in thick welded plates of Inconel 718 at room and cryogenic temperatures

    Science.gov (United States)

    Forman, R. G.

    1974-01-01

    Results of mechanical-properties and axial-load fatigue and fracture tests performed on thick welded plates of Inconel 718 superalloy are presented. The test objectives were to determine the tensile strength properties and the crack-growth behavior in electron-beam, plasma-arc, and gas tungsten are welds for plates 1.90 cm (0.75 in) thick. Base-metal specimens were also tested to determine the flaw-growth behavior. The tests were performed in room-temperature-air and liquid nitrogen environments. The experimental crack-growth-rate data are correlated with theoretical crack-growth-rate predictions for semielliptical surface flaws.

  16. Fatigue life prediction of casing welded pipes by using the extended finite element method

    OpenAIRE

    2016-01-01

    The extended finite element (XFEM) method has been used to simulate fatigue crack growth in casing pipe, made of API J55 steel by high-frequency welding, in order estimate its structural integrity and life. Based on the critical value of stress intensity factor KIc, measured in different regions of welded joint, the crack was located in the base metal as the region with the lowest resistance to crack initiation and propagation. The XFEM was first applied to the 3 point bending specimens to...

  17. Graphite composite truss welding and cap section forming subsystems. Volume 1: Executive summary. [large space structures

    Science.gov (United States)

    1980-01-01

    A rolltrusion process was developed for forming of a hybrid, single-ply woven graphite and glass fiber cloth, impregnated with a polysulfone resin and coated with TI02 pigmented P-1700 resin into strips for the on-orbit fabrication of triangular truss segments. Ultrasonic welding in vacuum showed no identifiable effects on weld strength or resin flow characteristics. An existing bench model cap roll forming machine was modified and used to roll form caps for the prototype test truss and for column test specimens in order to test local buckling and torsional instability characteristics.

  18. Experimental Evaluation of Mechanical Properties of Friction Welded Dissimilar Steels under Varying Axial Pressures

    Directory of Open Access Journals (Sweden)

    Handa Amit

    2016-07-01

    Full Text Available The present study emphasizes on joints two industrially important materials AISI 304 with AISI 1021steels, produced by friction welding have been investigated. Samples were welded under different axial pressures ranging from 75MPa to 135MPa, at constant speed of 920rpm. The tensile strength, torsional strength, impact strength and micro hardness values of the weldments were determined and evaluated. Simultaneously the fractrography of the tensile tested specimens were carried out, so as to understand the failure analysis. It was observed that improved mechanical properties were noticed at higher axial pressures. Ductile failures of weldments were also observed at 120MPa and 135MPa axial pressures during fractography analysis.

  19. Laser based spot weld characterization

    Science.gov (United States)

    Jonietz, Florian; Myrach, Philipp; Rethmeier, Michael; Suwala, Hubert; Ziegler, Mathias

    2016-02-01

    Spot welding is one of the most important joining technologies, especially in the automotive industry. Hitherto, the quality of spot welded joints is tested mainly by random destructive tests. A nondestructive testing technique offers the benefit of cost reduction of the testing procedure and optimization of the fabrication process, because every joint could be examined. This would lead to a reduced number of spot welded joints, as redundancies could be avoided. In the procedure described here, the spot welded joint between two zinc-coated steel sheets (HX340LAD+Z100MB or HC340LA+ZE 50/50) is heated optically on one side. Laser radiation and flash light are used as heat sources. The melted zone, the so called "weld nugget" provides the mechanical stability of the connection, but also constitutes a thermal bridge between the sheets. Due to the better thermal contact, the spot welded joint reveals a thermal behavior different from the surrounding material, where the heat transfer between the two sheets is much lower. The difference in the transient thermal behavior is measured with time resolved thermography. Hence, the size of the thermal contact between the two sheets is determined, which is directly correlated to the size of the weld nugget, indicating the quality of the spot weld. The method performs well in transmission with laser radiation and flash light. With laser radiation, it works even in reflection geometry, thus offering the possibility of testing with just one-sided accessibility. By using heating with collimated laser radiation, not only contact-free, but also remote testing is feasible. A further convenience compared to similar thermographic approaches is the applicability on bare steel sheets without any optical coating for emissivity correction. For this purpose, a proper way of emissivity correction was established.

  20. Evaluation of shear bond strength of porcelain bonded to laser welded titanium surface and determination of mode of bond failure.

    Science.gov (United States)

    Patil, Narendra P; Dandekar, Minal; Nadiger, Ramesh K; Guttal, Satyabodh S

    2010-09-01

    The aim of this study was to evaluate the shear bond strength of porcelain to laser welded titanium surface and to determine the mode of bond failure through scanning electron microscopy (SEM) and energy dispersive spectrophotometry (EDS). Forty five cast rectangular titanium specimens with the dimension of 10 mm x 8 mm x 1 mm were tested. Thirty specimens had a perforation of 2 mm diameter in the centre. These were randomly divided into Group A and B. The perforations in the Group B specimens were repaired by laser welding using Cp Grade II titanium wire. The remaining 15 specimens were taken as control group. All the test specimens were layered with low fusing porcelain and tested for shear bond strength. The debonded specimens were subjected to SEM and EDS. Data were analysed with 1-way analysis of variance and Student's t-test for comparison among the different groups. One-way analysis of variance (ANOVA) showed no statistically significant difference in shear bond strength values at a 5% level of confidence. The mean shear bond strength values for control group, Group A and B was 8.4 +/- 0.5 Mpa, 8.1 +/- 0.4 Mpa and 8.3 +/- 0.3 Mpa respectively. SEM/EDS analysis of the specimens showed mixed and cohesive type of bond failure. Within the limitations of the study laser welding did not have any effect on the shear bond strength of porcelain bonded to titanium.

  1. Laser Welding in Electronic Packaging

    Science.gov (United States)

    2000-01-01

    The laser has proven its worth in numerous high reliability electronic packaging applications ranging from medical to missile electronics. In particular, the pulsed YAG laser is an extremely flexible and versatile too] capable of hermetically sealing microelectronics packages containing sensitive components without damaging them. This paper presents an overview of details that must be considered for successful use of laser welding when addressing electronic package sealing. These include; metallurgical considerations such as alloy and plating selection, weld joint configuration, design of optics, use of protective gases and control of thermal distortions. The primary limitations on use of laser welding electronic for packaging applications are economic ones. The laser itself is a relatively costly device when compared to competing welding equipment. Further, the cost of consumables and repairs can be significant. These facts have relegated laser welding to use only where it presents a distinct quality or reliability advantages over other techniques of electronic package sealing. Because of the unique noncontact and low heat inputs characteristics of laser welding, it is an ideal candidate for sealing electronic packages containing MEMS devices (microelectromechanical systems). This paper addresses how the unique advantages of the pulsed YAG laser can be used to simplify MEMS packaging and deliver a product of improved quality.

  2. Fracture strength of different soldered and welded orthodontic joining configurations with and without filling material

    Directory of Open Access Journals (Sweden)

    Jens Johannes Bock

    2008-10-01

    Full Text Available The aim of this study was to compare the mechanical strength of different joints made by conventional brazing, TIG and laser welding with and without filling material. Five standardized joining configurations of orthodontic wire in spring hard quality were used: round, cross, 3 mm length, 9 mm length and 7 mm to orthodontic band. The joints were made by five different methods: brazing, tungsten inert gas (TIG and laser welding with and without filling material. For the original orthodontic wire and for each kind of joint configuration or connecting method 10 specimens were carefully produced, totalizing 240. The fracture strengths were measured with a universal testing machine (Zwick 005. Data were analyzed by ANOVA (p=0.05 and Bonferroni post hoc test (p=0.05. In all cases, brazing joints were ruptured on a low level of fracture strength (186-407 N. Significant differences between brazing and TIG or laser welding (p<0.05, Bonferroni post hoc test were found in each joint configuration. The highest fracture strength means were observed for laser welding with filling material and 3 mm joint length (998 N. Using filling materials, there was a clear tendency to higher mean values of fracture strength in TIG and laser welding. However, statistically significant differences were found only in the 9-mm long joints (p<0.05, Bonferroni post hoc test. In conclusion, the fracture strength of welded joints was positively influenced by the additional use of filling material. TIG welding was comparable to laser welding except for the impossibility of joining orthodontic wire with orthodontic band.

  3. Enhancing Stud Arc Welding Technique Vai Utilizing FuzzyLogic Approach (FLA

    Directory of Open Access Journals (Sweden)

    Nabeel K. Abid AL-Sahib

    2013-01-01

    Full Text Available A fuzzy logic approach (FLA application in the process of stud arc welding environment was implemented under the condition of fuzziness input data. This paper is composed of the background of FLA, related research work review and points for developing in stud welding manufacturing. Then, it investigates thecase of developingstud arc welding process on the controversial certaintyof available equipment and human skills.Five parameters (welding time, sheet thickness, type of coating, welding current and stud shape were studied.A pair of parameter was selected asiteration whichis welding current and welding time and used for verification corresponding with tensile strength as output results and this willconsider it as schema for other cases.The testing result in the case of crisp (exact value verifyingied the uncertainty value of some criteria selected which open the concept to make the decision making process for some advance cases without implementation. This paper applied the proposed methodology using Matlab program, the graphic user interface (GUI fuzzy tool box for the case study of screw DABOTEKSTUD welding machine, for 6 mm diameter stud. The sheet materials are (K14358 and K52355 according to (USN standards, and the stud materials are (54NiCrMoS6 and 4OCrMnMoS8-6 according to (DIN standards.This given information is very inevitable for the conventional crisp determination of the tensile stress for the particular specimens experimented and also for verifying the tensile test value estimate in the case of changing to a fuzzy value for two of the input variables.

  4. Ultrasonic imaging and evaluation of electron beam welds in copper canisters

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, T.; Ping Wu [Uppsala Univ. (Sweden). Dept. of Materials Science

    2001-08-01

    An EB weld, similarly to other types of welds, is characterized by a layered structure consisting of a host material zone (HMZ), a heat-affected zone (HAZ), and a fusion zone (FZ). A high quality ultrasonic image with well pronounced both HAZ and FZ is required for the evaluation of EB weld. Since the size of grains in the HMZ, HAZ and FZ differs considerably (usually grains are fine in the HMZ, get bigger in the HAZ, and become coarse in the FZ), the scattering patterns (associated with imaging contrast) in the zones are different. Since the scattering patterns are frequency-dependent, the HAZ and the FZ cannot be satisfactorily imaged simultaneously using a single band-limited ultrasonic transducer, which is common in NDE. Our aim, presented in this paper was obtaining a satisfactory imaging of the structure and flaws located both in the HAZ and FZ of an EB weld simultaneously. The idea consists in using a pair of transducers with different center frequencies. An experimental study has been conducted in which focused transducers were used to find appropriate frequency ranges best suitable for the imaging of different zones of the EB weld. The results have demonstrated that for the EB welds in our specimens an ultrasound with a frequency range of 4-5 MHz was suitable for the HAZ while satisfactory images of the FZ could be obtained using a frequency range of 2-3 MHz. A pair of transducers with the above frequency ranges yielded clear images of the layered structure of an EB weld. This means that the HAZ and FZ could be clearly distinguished using those transducers enabling estimation of the weld parameters, e.g. the thickness of the HAZ and HZ, and the grain sizes in different zones.

  5. Artificial neural networks application for modeling of friction stir welding effects on mechanical properties of 7075-T6 aluminum alloy

    Science.gov (United States)

    Maleki, E.

    2015-12-01

    Friction stir welding (FSW) is a relatively new solid-state joining technique that is widely adopted in manufacturing and industry fields to join different metallic alloys that are hard to weld by conventional fusion welding. Friction stir welding is a very complex process comprising several highly coupled physical phenomena. The complex geometry of some kinds of joints makes it difficult to develop an overall governing equations system for theoretical behavior analyse of the friction stir welded joints. Weld quality is predominantly affected by welding effective parameters, and the experiments are often time consuming and costly. On the other hand, employing artificial intelligence (AI) systems such as artificial neural networks (ANNs) as an efficient approach to solve the science and engineering problems is considerable. In present study modeling of FSW effective parameters by ANNs is investigated. To train the networks, experimental test results on thirty AA-7075-T6 specimens are considered, and the networks are developed based on back propagation (BP) algorithm. ANNs testing are carried out using different experimental data that they are not used during networks training. In this paper, rotational speed of tool, welding speed, axial force, shoulder diameter, pin diameter and tool hardness are regarded as inputs of the ANNs. Yield strength, tensile strength, notch-tensile strength and hardness of welding zone are gathered as outputs of neural networks. According to the obtained results, predicted values for the hardness of welding zone, yield strength, tensile strength and notch-tensile strength have the least mean relative error (MRE), respectively. Comparison of the predicted and the experimental results confirms that the networks are adjusted carefully, and the ANN can be used for modeling of FSW effective parameters.

  6. Totally confined explosive welding

    Science.gov (United States)

    Bement, L. J. (Inventor)

    1978-01-01

    The undesirable by-products of explosive welding are confined and the association noise is reduced by the use of a simple enclosure into which the explosive is placed and in which the explosion occurs. An infrangible enclosure is removably attached to one of the members to be bonded at the point directly opposite the bond area. An explosive is completely confined within the enclosure at a point in close proximity to the member to be bonded and a detonating means is attached to the explosive. The balance of the enclosure, not occupied by explosive, is filled with a shaped material which directs the explosive pressure toward the bond area. A detonator adaptor controls the expansion of the enclosure by the explosive force so that the enclosure at no point experiences a discontinuity in expansion which causes rupture. The use of the technique is practical in the restricted area of a space station.

  7. Welding of Prosthetic Alloys

    Directory of Open Access Journals (Sweden)

    Wojciechowska M.

    2015-04-01

    Full Text Available This paper presents the techniques of joining metal denture elements, used in prosthetic dentistry: the traditional soldering technique with a gas burner and a new technique of welding with a laser beam; the aim of the study was to make a comparative assessment of the quality of the joints in view of the possibility of applying them in prosthetic structures. Fractographic examinations were conducted along with tensile strength and impact strength tests, and the quality of the joints was assessed compared to the solid metal. The experiments have shown that the metal elements used to make dentures, joined by the technique which employs a laser beam, have better strength properties than those achieved with a gas burner.

  8. Ship construction and welding

    CERN Document Server

    Mandal, Nisith R

    2017-01-01

    This book addresses various aspects of ship construction, from ship types and construction materials, to welding technologies and accuracy control. The contents of the book are logically organized and divided into twenty-one chapters. The book covers structural arrangement with longitudinal and transverse framing systems based on the service load, and explains basic structural elements like hatch side girders, hatch end beams, stringers, etc. along with structural subassemblies like floors, bulkheads, inner bottom, decks and shells. It presents in detail double bottom construction, wing tanks & duct keels, fore & aft end structures, etc., together with necessary illustrations. The midship sections of various ship types are introduced, together with structural continuity and alignment in ship structures. With regard to construction materials, the book discusses steel, aluminum alloys and fiber reinforced composites. Various methods of steel material preparation are discussed, and plate cutting and form...

  9. NASA welding assessment program

    Science.gov (United States)

    Stofel, E. J.

    1984-01-01

    A long duration test was conducted for comparing various methods of attaching electrical interconnects to solar cells for near Earth orbit spacecraft. Representative solar array modules were thermally cycled for 36,000 cycles between -80 and +80 C. The environmental stress of more than 6 years on a near Earth spacecraft as it cycles in and out of the earth's shadow was simulated. Evaluations of the integrity of these modules were made by visual and by electrical examinations before starting the cycling and then at periodic intervals during the cycling tests. Modules included examples of parallel gap and of ultrasonic welding, as well as soldering. The materials and fabrication processes are state of the art, suitable for forming large solar arrays of spacecraft quality. The modules survived this extensive cycling without detectable degradation in their ability to generate power under sunlight illumination.

  10. A study of processes for welding pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Weston, J. (ed.)

    1991-07-01

    A review was made of exisiting and potential processes for welding pipelines: fusion welding (arc, electron beam, laser, thermit) and forge welding (friction, flash, magnetically impelled arc butt, upset butt, explosive, shielded active gas, gas pressure). Consideration of J-lay operations gave indications that were reflections of the status of the processes in terms of normal land and offshore S-lay operation: forge welding processes, although having promise require considerable development; fusion welding processes offer several possibilities (mechanized GMA welding likely to be used in 1991-2); laser welding requires development in all pipeline areas: a production machine for electron beam welding will involve high costs. Nondestructive testing techniques are also reviewed. Demand for faster quality assessment is being addressed by speeding radiographic film processing and through the development of real time radiography and automatic ultrasonic testing. Conclusions on most likely future process developments are: SMAW with cellulosic electrodes is best for tie-ins, short pip runs; SMAW continues to be important for small-diameter lines, although mechanized GMA could be used, along with mechanical joining, MIAB, radial fraction, and flash butt; mechanized GMA welding is likely to predominate for large diameter lines and probably will be used for the first J-lay line (other techniques could be used too); and welding of piping for station facilities involves both shop welding of sub-assemblies and on-site welding of pipe and sub-assemblies to each other (site welding uses both SMAW and GMAW). Figs, tabs.

  11. Performance evaluation of quality monitor models in spot welding

    Institute of Scientific and Technical Information of China (English)

    Zhang Zhongdian; Li Dongqing; Wang Kai

    2005-01-01

    Performance of quality monitor models in spot welding determines the monitor precision directly, so it's crucial to evaluate it. Previously, mean square error ( MSE ) is often used to evaluate performances of models, but it can only show the total errors of finite specimens of models, and cannot show whether the quality information inferred from models are accurate and reliable enough or not. For this reason, by means of measure error theory, a new way to evaluate the performances of models according to the error distributions is developed as follows: Only if correct and precise enough the error distribution of model is, the quality information inferred from model is accurate and reliable.

  12. Creep rupture behavior of welded Grade 91 steel

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, Triratna [Department of Chemical and Materials Engineering, University of Idaho, Moscow, ID 83844 (United States); Basirat, Mehdi [Department of Mechanical Engineering, University of Idaho, Moscow, ID 83844 (United States); Alsagabi, Sultan; Sittiho, Anumat [Department of Chemical and Materials Engineering, University of Idaho, Moscow, ID 83844 (United States); Charit, Indrajit, E-mail: icharit@uidaho.edu [Department of Chemical and Materials Engineering, University of Idaho, Moscow, ID 83844 (United States); Potirniche, Gabriel P. [Department of Mechanical Engineering, University of Idaho, Moscow, ID 83844 (United States)

    2016-07-04

    Creep rupture behavior of fusion welded Grade 91 steel was studied in the temperature range of 600 – 700 °C and at stresses of 50–200 MPa. The creep data were analyzed in terms of the Monkman-Grant relation and Larson-Miller parameter. The creep damage tolerance factor was used to identify the origin of creep damage. The creep damage was identified as the void growth in combination with microstructural degradation. The fracture surface morphology of the ruptured specimens was studied by scanning electron microscopy and deformed microstructure examined by transmission electron microscopy, to further elucidate the rupture mechanisms.

  13. Effect of Welding Methods on the Structure and Mechanical Properties of Welded Joints of Screw Piles

    Science.gov (United States)

    Golikov, N. I.; Sidorov, M. M.; Stepanova, K. V.

    2016-11-01

    Mechanical properties and characteristics of the structure of welded joints of screw piles are studied. It is shown that cast tips from steel 25L do not meet the performance specifications for operation in the Northern climatic zone. Quality welded joints of screw piles can be obtained by semiautomatic welding in an environment of CO2 with Sv-08G2S welding wire.

  14. Development of technique for laser welding of biological tissues using laser welding device and nanocomposite solder.

    Science.gov (United States)

    Gerasimenko, A; Ichcitidze, L; Podgaetsky, V; Ryabkin, D; Pyankov, E; Saveliev, M; Selishchev, S

    2015-08-01

    The laser device for welding of biological tissues has been developed involving quality control and temperature stabilization of weld seam. Laser nanocomposite solder applied onto a wound to be weld has been used. Physicochemical properties of the nanocomposite solder have been elucidated. The nature of the tissue-organizing nanoscaffold has been analyzed at the site of biotissue welding.

  15. ALGORITHM AND IMPLEMENTATION OF AUTO-SEARCHING WELD LINE FOR WELDING MOBILE ROBOT

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ke; L(U) Xueqin; WU Yixiong; LOU Songnian

    2006-01-01

    An algorithm of auto-searching weld line for welding mobile robot is presented.Auto-searching weld line is that the robot can automatically recognize a weld groove according to the characteristics of the weld groove before welding, and then adjust itself posture to the desired status preparing for welding, namely, it is a process that the robot autonomously aligns itself to the center of welding seam. Firstly, the configuration of welding mobile robot with the function of auto-searching weld line is introduced, then the algorithm and implementation of auto-searching weld line are presented on the basis of kinematics model of the robot, at last trajectory planning among auto-searching weld line is investigated in detail. The experiment result shows that the developed welding mobile robot can successfully implement the task of auto-searching weld line before welding, tracking error precision can be controlled to approximate ± 1.5 mm, and satisfy the requirement of practical welding project.

  16. EMAT weld inspection and weld machine diagnostic system for continuous coil processing lines

    Science.gov (United States)

    Latham, Wayne M.; MacLauchlan, Daniel T.; Geier, Dan P.; Lang, Dennis D.

    1996-11-01

    Weld breaks of steel coil during cold rolling and continuous pickling operations are a significant source of lost productivity and product yield. Babcock and Wilcox Innerspec Technologies has developed a weld process control system which monitors the key variables of the welding process and determines the quality of the welds generated by flash butt welding equipment. This system is known as the Temate 2000 Automated Flash Butt Weld Inspection and Weld Machine Diagnostic System. The Temate 2000 system utilizes electro- magnetic acoustic transducer (EMAT) technology as the basis for performing on-line, real-time, nondestructive weld quality evaluation. This technique accurately detects voids, laps, misalignment and over/under trim conditions in the weld. Results of the EMAT weld inspection are immediately presented to the weld machine operator for disposition. Welding process variables such as voltage, current, platen movements and upset pressures are monitored and collected with the high speed data acquisition system. This data is processed and presented in real-time display to indicate useful welding process information such as platen crabbing, upset force, peak upset current, and many others. Alarming for each variable is provided and allows detailed maintenance reports and summary information to be generated. All weld quality and process parameter data are stored, traceable to each unique weld, and available for post process evaluation. Installation of the Temate 2000 system in a major flat rolled steel mill has contributed to near elimination of weld breakage and increased productivity at this facility.

  17. Determination through the distortions analysis of the best welding sequence in longitudinal welds VATS electron beam welding FE simulation

    Energy Technology Data Exchange (ETDEWEB)

    Guirao, J., E-mail: julio@natec-ingenieros.co [Numerical Technologies, S.L., Marques de San Esteban No. 52, 33206 Gijon (Spain); Rodriguez, E. [Department of Mechanical Engineering, University of Oviedo, Campus de Viesques, 33203 Gijon (Spain); Bayon, A. [Vacuum Vessel Group, Fusion for Energy, Josep Pla 2, 08019 Barcelona (Spain); Bouyer, F. [DCNS, Indret 44620 LA MONTAGNE (France); Pistono, J. [Department of Thermal Machines and Motors, University of Oviedo, Campus de Viesques, 33203 Gijon (Spain); Jones, L. [Vacuum Vessel Group, Fusion for Energy, Josep Pla 2, 08019 Barcelona (Spain)

    2010-08-15

    This paper presents a detailed finite element simulation of the longitudinal rib welds of Vessel Advanced Technology Segment (VATS) by e-beam welding. Nine different simulation sequences were carried out to explain the different mechanisms that drive the distortions process during welding and to lead to an optimum sequence which minimizes the final distortions. The simulations were used to guide the manufacture of the final sequence of the VATS. Distortion measurements taken after welding compared very well with the simulated results.

  18. Analysis of solidification cracks in welds of Al-Mg-Si A6351 type alloy welded by high frequency pulsed TIG process. 1st report. Evaluation of solidification crack susceptibility by means of Houldcroft test

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, M.; Machida, S. [The Univ. of Tokyo, Tokyo (Japan); Taniguchi, C.; Brandi, S. [Univ. of Sao Paulo, Sao Paulo, SP (Brazil)

    1994-08-05

    The main objective of this work is to study the susceptibility to solidification crack by means of Houldcroft test on Al-Mg-Si alloy A6351 welded by TIG process using a D.C. straight polarity and pulsed current with high frequency with varied parameters. The parameters are welding speed, current, arc pulse, frequency, and heat input per unit weld length. The effect of grain structures on the susceptibility of solidification crack is evaluated as well as the welding pool geometry in which these structures has developed. The `quasi-stationary` state is studied for the specimen geometry used, and the process efficiencies are estimated using welding pool width method. The trend of increase of crack length with the welding speed observed in no pulsed arc conditions is significantly changed with the introduction of the pulsed arc. Therefore, the pulsed frequency and the welding speed seem to be competing parameters in effect on the development of solidification crack. This work shows that the generalized tendency of solidification crack susceptibility with regard to the obtained grain structures as presented in previous works is not a general trend. 40 refs., 13 figs., 3 tabs.

  19. TECHNOLOGICAL ISSUES IN MECHANISED FEED WIG/TIG WELDING SURFACING OF WELDING

    Directory of Open Access Journals (Sweden)

    BURCA Mircea

    2016-09-01

    manual welding tests in the light of using the process for welding surfacing being known that in such applications mechanised operations are recommended whenever possible given the latter strengths i.e. increased productivity and quality deposits. The research also aims at achieving a comparative a study between wire mechanised feed based WIG manual welding and the manual rod entry based manual welding in terms of geometry deposits, deposits aesthetics, operating technique, productivity, etc . In this regard deposits were made by means of two welding procedures, and subsequently welding surfacing was made with the optimum values of the welding parameters in this case.

  20. Effects of welding technology on welding stress based on the finite element method

    Science.gov (United States)

    Fu, Jianke; Jin, Jun

    2017-01-01

    Finite element method is used to simulate the welding process under four different conditions of welding flat butt joints. Welding seams are simulated with birth and death elements. The size and distribution of welding residual stress is obtained in the four kinds of welding conditions by Q345 manganese steel plate butt joint of the work piece. The results shown that when using two-layers welding,the longitudinal and transverse residual stress were reduced;When welding from Middle to both sides,the residual stress distribution will change,and the residual stress in the middle of the work piece was reduced.

  1. Oxidation behavior of base metal, weld metal and HAZ regions of SMAW weldment in ASTM SA210 GrA1 steel

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ravindra [Metallurgical and Materials Engineering Department, Indian Institute of Technology Roorkee, Roorkee 247667 (India)], E-mail: ravirs_2002@rediffmail.com; Tewari, V.K.; Prakash, Satya [Metallurgical and Materials Engineering Department, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

    2009-06-24

    Shielded metal arc welding (SMAW) was used to weld together ASTM SA210 GrA1 steel. The oxidation studies were conducted on different regions of shielded metal arc weldment i.e., base metal, weld metal and heat affected zone (HAZ) specimens after exposure to air at 900 deg. C under cyclic conditions. The thermo-gravimetric technique was used to establish kinetics of oxidation. X-ray diffraction (XRD) and scanning electron microscopy/energy-dispersive analysis (SEM/EDAX) techniques were used to analyze the oxidation products. Base metal showed more weight gain than that of weld metal and HAZ. The HAZ specimen showed the least weight gain due to the formation of densely inner oxide scale.

  2. Comparative study of residual stress by table of coordinates and X-ray diffraction in a welded joint; Estudo comparativo das tensoes residuais por mesa de coordenadas e DR-X numa junta soldada

    Energy Technology Data Exchange (ETDEWEB)

    Siqueira Filho, A.V.; Rolim, T.L.; Yadava, Y.P.; Ferreira, R.A.S., E-mail: anibal_siqueira@yahoo.com.b [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Engenharia Mecanica; Cardoso, F.I.B. [Universidade de Pernambuco (POLI/UPE), Recife, PE (Brazil); Guimaraes, P.B. [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco, Recife, PE (Brazil)

    2010-07-01

    Residual stresses in a welded joint of naval steel ASTM AH-32 was measured either by the displacements of referenced points with a coordinated table (CT) or by x-ray diffraction (X-DR) after welding. For all tests, the welding was performed by a certified welder in the SMAW process, using an AWS E 7018 G3 electrode. Before welding, small holes evenly spaced were made in the specimens to be mapped on a coordinated table (CT). After labeling, the specimens were submitted to the welding process and new measurements by (CT) to evaluate the displacements produced by the tensions generated. In parallel, residual stress were measured by DR-X for validation of this new measurement methodology. (author)

  3. Modeling of welded bead profile for rapid prototyping by robotic MAG welding

    Institute of Scientific and Technical Information of China (English)

    CAO Yong; ZHU Sheng; WANG Tao; WANG Wanglong

    2009-01-01

    As a deposition technology, robotic metal active gas(MAG) welding has shown new promise for rapid prototyping (RP) of metallic parts. During the process of metal forming using robotic MAG welding, sectional profile of single-pass welded bead is critical to formed accuracy and quality of metal pans. In this paper, the experiments of single-pass welded bead for rapid prototyping using robotic MAG welding were carried out. The effect of some edge detectors on the cross-sectional edge of welded bead was discussed and curve fitting was applied using leat square fitting. Consequently, the mathematical model of welded bead profile was developed. The experimental results show that good shape could be obtained under suitable welding parameters. Canny operawr is suitable to edge detection of welded bead profile, and the mathematical model of welded bead profile developed is approximately parabola.

  4. Predicting effects of diffusion welding parameters on welded joint properties by artificial neural network

    Institute of Scientific and Technical Information of China (English)

    刘黎明; 祝美丽; 牛济泰; 张忠典

    2001-01-01

    The static model for metal matrix composites in diffusion welding was established by means of artificial neural network method. The model presents the relationship between weld joint properties and welding parameters such as welding temperature, welding pressure and welding time. Through simulating the diffusion welding process of SiCw/6061Al composite, the effects of welding parameters on the strength of welded joint was studied and optimal technical parameters was obtained. It is proved that this method has good fault-tolerant ability and versatility and can overcome the shortage of the general experiment. The established static model is in good agreement with the actual welding process, so it becomes a new path for studying the weldability of new material.

  5. Effect of Laser Welding Parameters on Formation of NiTi Shape Memory Alloy Welds

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2014-01-01

    Full Text Available In this work experimental trials of welding of NiTi flat plates with 2.0 mm thickness were conducted using a 4.5 kW continuous wave (CW Nd:YAG laser. The influences of laser output power, welding speed, defocus amount and side-blow shielding gas flow rate on the morphology, welding depth and width, and quality of the welded seam were investigated. Meanwhile, the effects of heat input on the mechanical and functional properties of welded joints were studied. The results show that laser welding can take better formation in NiTi alloys. The matching curves with laser power and welding speed affecting different formation of welds were experimentally acquired, which can provide references for laser welding and engineering application of NiTi alloy. The heat input has obvious effects on the ultimate tensile strength (UTS and shape memory behavior of the welded joints.

  6. Effect of Multi-repair Welding on Fatigue Performance of Aluminum Alloy Profile Welded Joint

    Science.gov (United States)

    Diao, You-De; Shi, Chun-Yuan; Tian, Hong-Lei

    2016-05-01

    Aluminum alloy profile has been widely used in the manufacture of the rail vehicles. But it's necessary for the repair welding of the welded joints to be conducted because some defects exist in the weld such as porosity, inclusions and incomplete penetrations in the welding processes. In this paper, the influence of the multi-repair welding of 6005A aluminum alloy profile butt welded joints on the fatigue performance are investigated based on the results of fatigue tests. The parameters of curves and the fatigue strength of the welded joints are calculated, and Goodman fatigue limit diagram is also obtained. The results show that fatigue strength of aluminum alloy profile butt welded joints, in condition of 107 cycle life, meet the standard requirement for the as-welded, repair welded state one time or two times respectively.

  7. Characteristics of Welding Crack Defects and Failure Mode in Resistance Spot Welding of DP780 Steel

    Institute of Scientific and Technical Information of China (English)

    Xiao-pei WANG; Yong-qiang ZHANG; Jian-bin JU; Jian-qiang ZHANG; Jian-wei YANG

    2016-01-01

    The mechanical properties of welded joints in resistance spot welding of DP780 steel were tested,and three dif-ferent types of welding cracks in welded joints were investigated by optical microscopy,scanning electron microscopy and electron back-scattered diffraction.Finally,the failure mode of the welded joints in shear tensile test was dis-cussed.It is found the shear tensile strength of welded joints can be greatly improved by adding preheating current or tempering current.The surface crack in welded joint is intergranular fracture,while the inner crack in welded joint is transgranular fracture,and the surface crack on the edge of the electrode imprint can be improved by adding prehea-ting current or tempering current.The traditional failure mode criterion advised by American Welding Society is no longer suitable for DP780 spot welds and the critical nugget size suggested by Pouranvari is overestimated.

  8. Effects of welding parameters on the mechanical properties of inert gas welded 6063 Aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ertan, Taner [MAKO Corporation (Turkey); Uguz, Agah [Uludag Univ. (Turkey). Mechnical Engineering Dept.; Ertan, Rukiye

    2012-07-01

    The influence of welding parameters, namely welding current and gas flow rate, on the mechanical properties of Gas Tungsten Arc Welding (GTAW) and Shielded Metal Arc Welding (SMAW) welded 6063 Aluminum alloy (AA 6063) has been investigated. In order to study the effect of the welding current and gas flow rate, microstructural examination, hardness measurements and room temperature tensile tests have been carried out. The experimental results show that the mechanical properties of GTAW welded joints have better mechanical properties than those of SMAW welded joints. Increasing the welding current appeared to have a beneficial effect on the mechanical properties. However, either increasing or decreasing the gas flow rate resulted in a decrease of hardness and tensile strength. It was also found that, the highest strength was obtained in GTAW welded samples at 220 A and 15 l/min gas flow rate.

  9. Experimental and simulated strength of spot welds

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Bennedbæk, Rune A.K.; Larsen, Morten B.

    2014-01-01

    Weld strength testing of single spots in DP600 steel is presented for the three typical testing procedures, i.e. tensile-shear, cross-tension and peel testing. Spot welds are performed at two sets of welding parameters and strength testing under these conditions is presented by load-elongation cu......Weld strength testing of single spots in DP600 steel is presented for the three typical testing procedures, i.e. tensile-shear, cross-tension and peel testing. Spot welds are performed at two sets of welding parameters and strength testing under these conditions is presented by load......-elongation curves revealing the maximum load and the elongation at break. Welding and strength testing is simulated by SORPAS® 3D, which allows the two processes to be prepared in a combined simulation, such that the simulated welding properties are naturally applied to the simulation of strength testing. Besides...

  10. Polyimide weld bonding for titanium alloy joints

    Science.gov (United States)

    Vaughan, R. W.; Kurland, R. M.

    1974-01-01

    Two weld bonding processes were developed for joining titanium alloy; one process utilizes a weld-through technique and the other a capillary-flow technique. The adhesive used for the weld-through process is similar to the P4/A5F system. A new polyimide laminating resin, BFBI/BMPM, was used in the capillary-flow process. Static property information was generated for weld-bonded joints over the temperature range of 219 K (-65 F) to 561 K (+550 F) and fatigue strength information was generated at room temperature. Significant improvement in fatigue strength was demonstrated for weld-bonded joints over spot-welded joints. A demonstration was made of the applicability of the weld-through weld-bonding process for fabricating stringer stiffened skin panels.

  11. Development of methodology for measurements of residual stresses in welded joint based on displacement of points in a coordinated table

    Directory of Open Access Journals (Sweden)

    Aníbal Veras Siqueira Filho

    2013-04-01

    Full Text Available Residual stresses in a welded joint of ASTM A131 grade AH32 steel was measured either by the X-ray diffraction or by displacements of referenced points measured on a coordinate measuring machine before and after heat treatment. For all tests, the welding was performed with Shielded Metal Arc Welding, vertical-up position, by a certified welder. After welding, some specimens were subjected to marking, made through small holes evenly spaced and mapped on a coordinate measuring machine. After labeling, the samples were subjected to heat treatment at temperatures nearby recrystallization. After heat treatment, the samples were subjected to new measurements by coordinate measuring machine to evaluate the displacements of the points produced by the recrystallization. In parallel, residual stress measurements were made by XRD for validation of this new methodology. The results obtained either by X-ray or by coordinate measuring machine showed a good correlation between the two measurement methodologies employed.

  12. The Effects of Laser Peening and Shot Peening on Mechanical Properties in Friction Stir Welded 7075-T7351 Aluminum

    Science.gov (United States)

    Hatamleh, Omar

    2006-01-01

    Peening techniques like laser peening and shot peening were used to modify the surface of friction stir welded 7075-T7351 Aluminum Alloy specimens. The tensile coupons were machined such as the loading was applied in a direction perpendicular to the weld direction. The peening effects on the global and local mechanical properties through the different regions of the weld were characterized and assessed. The surface hardness levels resulting from various peening techniques were also investigated for both sides of the welds. Shot peening resulted in an increase to surface hardness levels, but no improvement was noticed on the mechanical properties. In contrast, mechanical properties were improved by laser peening when compared to the unpeened material.

  13. Cavitation Erosion Behavior of as-Welded Cu12Mn8Al3Fe2Ni Alloy

    Institute of Scientific and Technical Information of China (English)

    Xiaoya LI; Yonggui YAN; Zhenming XU; Jianguo LI

    2004-01-01

    Cavitation erosion behavior of as-welded Cu12Mn8Al3Fe2Ni alloy in 3.5% NaCl aqueous solution was studied by magnetostrictive vibratory device for cavitation erosion. The results show that the cavitation erosion resistance of the as-welded Cu12Mn8Al3Fe2Ni alloy is much more superior to that of the as-cast one. The cumulative mass loss and the mass loss rate of the as-welded Cu12Mn8Al3Fe2Ni alloy are almost 1/4 that of the as-cast one. SEM analysis of eroded specimens reveals that the as-cast Cu12Mn8Al3Fe2Ni alloy is attacked more severely than the as-welded one. Microcracks causing cavitation damage initiate at the phase boundaries.

  14. Specimen Collection and Submission Manual

    Science.gov (United States)

    2016-06-01

    a validated test algorithm . If there is insufficient specimen volume for testing, there may be delays, and the request may be referred to management...Additional guidance on packing and shipping infectious substances can be found through American Society for Microbiology: http://www.asm.org...images/pdf/Clinical/ pack -ship-7-15-2011.pdf TR-16-161 DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. UNCLASSIFIED

  15. Fungal contaminants in cytopathology specimens

    Directory of Open Access Journals (Sweden)

    Prashant Sharma

    2014-02-01

    Full Text Available A pseudo-epidemic of environmental fungi, most likely by Fusarium spp., leading to inappropriate investigations for disseminated systemic mycosis is described. Subtle diagnostic clues, including the specimens affected, the nature of the host response, and the type of fungal elements noted helped to determine the nature of contaminants. The potential pitfall can be avoided by the knowledge of pertinent disease biology, prompt consultation for infectious diseases, and investigations of the potential environmental sources followed by source control.

  16. Mechanical evaluation of linear friction welds in titanium alloys through indentation experiments; Evaluacion mecanica mediante tecnica de indentacion de soldaduras por friccion lineal en aleaciones de titanio

    Energy Technology Data Exchange (ETDEWEB)

    Corzo, M.; Casals, O.; Alcala, J.; Mateo, A.; Anglada, M.

    2005-07-01

    This article shows the results of a project that focuses on the characterization of the weld interface region of dissimilar joints between titanium alloys for aeronautical applications, specifically Ti-6Al-2Sn-4Zr-6Mo with Ti-6Al-4V, and Ti-6Al-2Sn-4Zr-6Mo with Ti-6Al-2Sn-4Zr-2Mo. The uniaxial flow stress and hardening response of the material containing the weld were analyzed following the finite elements simulations and mathematical formulations to correlate hardness and the amount of pile-up and sinking-in phenomena around sharp indenters with uniaxial mechanical properties. This allows to accurately stablishing the influence that welding process has on the mechanical response of the parts. Tests performed on these friction-welded specimens showed that the fine grained microstructures in the welds exhibited better properties than the base materials. (Author) 12 refs.

  17. Stress corrosion cracking in repair-welded 3.5 NiCrMoV steel in an actual turbine environment

    Energy Technology Data Exchange (ETDEWEB)

    Hitomi, Itoh; Takashi, Shige [Mitsubishi Heavy Industries, Ltd., Takasago Research and Development Center (Japan); Takashi, Momoo [Mitsubishi Heavy Industries, Ltd., Takasago Machinery Works (Japan)

    2001-07-01

    Temporary welding repairs are sometimes needed when damage occurs at the teeth of blade grooves in a low-pressure turbine rotor operated at the dry/wet boundary region. When repair welding has been performed for the 3,5 NiCrMoV steel used in low-pressure turbines, the soundness of the weld must be confirmed. For this reason, a laboratory investigation of susceptibility for stress corrosion cracking (SCC) was conducted for test specimens taken from simulated welds, and then an exposure test was conducted in an actual turbine environment for approximately 7,000 hours. As no SCC initiation was detected and also the propagation was extremely small, repair welding is deemed to be applicable. (author)

  18. Effect of Heat Treatment on Microstructure and Hot Impact Toughness of Various Zones of P91 Welded Pipes

    Science.gov (United States)

    Pandey, C.; Mahapatra, M. M.

    2016-06-01

    The new generation super critical thermal power plants are required to operate at enhanced thermal efficiency of over 50% to reduce the fuel consumption and environmental pollution. Creep strength-enhanced ferritic steels, commonly known as Cr-Mo alloys such as P91 (X10CrMoVNb 9-1) are such material of choice for the next generation power plants. The operating requirement of these next generation power plants is that steam temperature of around 650 °C is maintained. For such high-temperature application, creep strength of material is the primary consideration together with adequate weld heat-affected zone (HAZ) toughness. Present work deals with the effect of high service temperature on impact toughness of P91 (X10CrMoVNb 9-1) base material, weld fusion zone, and HAZ. The impact toughness of HAZ for conventional weld groove design and narrow weld groove design has been evaluated experimentally in as-welded and at different post-weld heat treatment conditions. Fractography of the impact toughness specimens of base metal, weld fusion zone, and HAZ was carried out using scanning electron microscope. The effects of heat treatment schemes on the percentage of element present at the fracture surface were also studied.

  19. Experimental determination of the weld penetration evolution in keyhole plasma arc welding

    Institute of Scientific and Technical Information of China (English)

    Hu Qingxian; Wu Chuansong; Zhang Yuming

    2007-01-01

    Keyhole plasma arc welding experiments are conducted to measure the weld geometry and penetration at different moments during the initial phase from igniting arc to quasi-steady state. Indirect information on keyhole formation and evolution in plasma arc welding can be extracted based on the weld macrophotograph at cross section. It has laid foundation to verify the mathematical models of keyhole plasma arc welding.

  20. Welding polarity effects on weld spatters and bead geometry of hyperbaric dry GMAW

    Science.gov (United States)

    Xue, Long; Wu, Jinming; Huang, Junfen; Huang, Jiqiang; Zou, Yong; Liu, Jian

    2016-03-01

    Welding polarity has influence on welding stability to some extent, but the specific relationship between welding polarity and weld quality has not been found, especially under the hyperbaric environment. Based on a hyperbaric dry welding experiment system, gas metal arc welding(GMAW) experiments with direct current electrode positive(DCEP) and direct current electrode negative(DCEN) operations are carried out under the ambient pressures of 0.1 MPa, 0.4 MPa, 0.7 MPa and 1.0 MPa to find the influence rule of different welding polarities on welding spatters and weld bead geometry. The effects of welding polarities on the weld bead geometry such as the reinforcement, the weld width and the penetration are discussed. The experimental results show that the welding spatters gradually grow in quantity and size for GMAW with DCEP, while GMAW with DCEN can produce fewer spatters comparatively with the increase of the ambient pressure. Compared with DCEP, the welding current and arc voltage waveforms for DCEN is more stable and the distribution of welding current probability density for DCEN is more concentrated under the hyperbaric environment. When the ambient pressure is increased from 0.1 MPa to 1.0 MPa, the effects of welding polarities on the reinforcement, the weld width and the penetration are as follows: an increase of 0.8 mm for the weld reinforcement is produced by GMAW with DCEN and 1.3 mm by GMAW with DCEP, a decrease of 7.2 mm for the weld width is produced by DCEN and 6.1 mm by DCEP; and an increase of 3.9 mm for the penetration is produced by DCEN and 1.9 mm by DCEP. The proposed research indicates that the desirable stability in the welding procedure can be achieved by GMAW with DCEN operation under the hyperbaric environment.

  1. Welding Polarity Effects on Weld Spatters and Bead Geometry of Hyperbaric Dry GMAW

    Institute of Scientific and Technical Information of China (English)

    XUE Long; WU Jinming; HUANG Junfen; HUANG Jiqiang; ZOU Yong; LIU Jian

    2016-01-01

    Welding polarity has influence on welding stability to some extent, but the specific relationship between welding polarity and weld quality has not been found, especially under the hyperbaric environment. Based on a hyperbaric dry welding experiment system, gas metal arc welding(GMAW) experiments with direct current electrode positive(DCEP) and direct current electrode negative(DCEN) operations are carried out under the ambient pressures of 0.1 MPa, 0.4 MPa, 0.7 MPa and 1.0 MPa to find the influence rule of different welding polarities on welding spatters and weld bead geometry. The effects of welding polarities on the weld bead geometry such as the reinforcement, the weld width and the penetration are discussed. The experimental results show that the welding spatters gradually grow in quantity and size for GMAW with DCEP, while GMAW with DCEN can produce fewer spatters comparatively with the increase of the ambient pressure. Compared with DCEP, the welding current and arc voltage waveforms for DCEN is more stable and the distribution of welding current probability density for DCEN is more concentrated under the hyperbaric environment. When the ambient pressure is increased from 0.1 MPa to 1.0 MPa, the effects of welding polarities on the reinforcement, the weld width and the penetration are as follows: an increase of 0.8 mm for the weld reinforcement is produced by GMAW with DCEN and 1.3 mm by GMAW with DCEP, a decrease of 7.2 mm for the weld width is produced by DCEN and 6.1 mm by DCEP; and an increase of 3.9 mm for the penetration is produced by DCEN and 1.9 mm by DCEP. The proposed research indicates that the desirable stability in the welding procedure can be achieved by GMAW with DCEN operation under the hyperbaric environment.

  2. Closed circuit television welding alignment system

    Energy Technology Data Exchange (ETDEWEB)

    Darner, G.S.

    1976-09-01

    Closed circuit television (CCTV) weld targeting systems were developed to provide accurate and repeatable positioning of the electrode of an electronic arc welder with respect to the parts being joined. A sliding mirror electrode holder was developed for use with closed circuit television equipment on existing weld fixturing. A complete motorized CCTV weld alignment system was developed to provide weld targeting for even the most critical positioning requirements.

  3. Stereoscopic Video Weld-Seam Tracker

    Science.gov (United States)

    Kennedy, Larry Z.

    1991-01-01

    Stereoscopic video camera and laser illuminator operates in conjunction with image-data-processing computer to locate weld seam and to map surface features in vicinity of seam. Intended to track seams to guide placement of welding torch in automatic welding system and to yield information on qualities of welds. More sensitive than prior optical seam trackers and suitable for use in production environment. Tracks nearly invisible gap between butted machined edges of two plates.

  4. Welding distortion of aluminium structural members

    Energy Technology Data Exchange (ETDEWEB)

    Goglio, L. [Politecnico di Torino (Italy). Dept. of Mech.; Gugliotta, A. [Politecnico di Torino (Italy). Dept. of Mech.; Pasquino, D. [Politecnico di Torino (Italy). Dept. of Mech.

    1996-12-31

    The paper deals with the angular distortion induced in aluminium tubular beams during welding to prepare T junctions. The research, based on experimental measurements, makes use of statistical methods to identify the parameters (beam section, weld length, welding direction, etc.) that influence the angular change. The results are discussed also considering a model known from the literature. It is found that the distortion is generally low and can be minimized by a proper welding process. (orig.)

  5. Laser welding of advanced high strength steels

    OpenAIRE

    Ahmed, Essam Ahmed Ali

    2011-01-01

    This research work focuses on characterization of CO2 laser beam welding (LBW) of dual phase (DP) and transformation induced plasticity (TRIP) steel sheets based on experimental, numerical simulation and statistical modeling approaches. The experimental work aimed to investigate the welding induced-microstructures, hardness, tensile properties and formability limit of laser welding butt joints of DP/DP, TRIP/TRIP and DP/TRIP steel sheets under different welding speeds. The effects of shieldin...

  6. Welding technology for rails. Rail no setsugo gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Okumura, M.; Karimine, K. (Nippon Steel Corp., Tokyo (Japan)); Uchino, K.; Sugino, K. (Nippon Steel Corp., Kitakyushu, Fukuoka (Japan). Technical Research Inst. of Yawata Works); Ueyama, K. (JR Railway Technical Research Inst., Tokyo (Japan))

    1993-08-01

    The rail joining technology is indispensable for making long welded rails. Flush butt welding, gas welding, enclosed arc welding, and thermit welding are used properly as the welding methods. A method for improving the joint reliability by controlling the residual stress distribution of welded joint is investigated to prepare high carbon component weld metal similar to the rail. Problems with each of the welding methods and the newly developed technology to solve the problems are outlined. Composition of the coating is improved also, and a high C system welding rod is developed which has satisfactory weldability. High performance and high efficient new enclosed arc welding technology not available by now is developed which utilizes high carbon welding metal as a new EA welding work technology, and put to practical use. As a result of this study, useful guides are obtained for the establishment of satisfactory thermit welding technology. 17 refs., 16 figs., 1 tab.

  7. Investigation on fracture behavior of the welded joint HAZ of ultra-fine grain steel SS400

    Institute of Scientific and Technical Information of China (English)

    朱政强; 陈立功; 荆洪阳; 葛景国; 倪纯珍; 饶德林

    2003-01-01

    The critical crack dimensions of both base-metal specimen and HAZ specimen are measured via wide-plate tensile tests. Based on the "fitness for purpose" principle, the fracture behavior of the ultra-fine grain steel SS400 welded joint HAZ is assessed. The test results indicate that overmatching is benefit for the whole capability's improvement of ultra-fine grain steel SS400. The test results are confirmed by using finite element method (FEM).

  8. Methodology to evaluate the crack growth rate by stress corrosion cracking in dissimilar metals weld in simulated environment of PWR nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Paula, Raphael G.; Figueiredo, Celia A.; Rabelo, Emerson G., E-mail: raphaelmecanica@gmail.com, E-mail: caf@cdtn.br, E-mail: egr@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    Inconel alloys weld metal is widely used to join dissimilar metals in nuclear reactors applications. It was recently observed failures of weld components in plants, which have triggered an international effort to determine reliable data on the stress corrosion cracking behavior of this material in reactor environment. The objective of this work is to develop a methodology to determine the crack growth rate caused by stress corrosion in Inconel alloy 182, using the specimen (Compact Tensile) in simulated PWR environment. (author)

  9. An Assessment of Molten Metal Detachment Hazards During Electron Beam Welding in Space

    Science.gov (United States)

    Fragomeni, James M.; Nunes, Arthur C., Jr.

    1998-01-01

    tension of the liquid metal. For a detachment the initial kinetic energy of the weld pool with respect to the plate has to exceed the energy to form the extra surface required for the detachment of the pool. The difficulty is in transferring the energy from the point of impact through the plate and sample to the cut edge. It is likely that not all of the kinetic energy is available for detaching the pool; some may be sequestered in weld pool oscillations. The coefficient of restitution for the collision will be lower than one if irreversible deformation, for example plastic flow deformation, takes place during the collision. Thus determining the amount of energy from an impact that actually reaches the molten metal droplet is critical. Various molten metal detachment scenarios were tested experimentally in an enclosed vacuum chamber using the Ukrainian Universal Hand Tool, an electron beam welder designed for space welding. The experimental testing was performed in a 4 ft. X 4 ft. vacuum chamber at Marshall Space Flight Center, evacuated to vacuum levels of at least 50 microTorr, and also some welding garment material was utilized to observe the effect of the molten metal detachments on the material. A "carillon" apparatus consisting of four pendulum hammer strikers, each weighing approximately 3.65 lbs, raised to predetermined specific heights was used to apply an impact force to the weld sample/plate during electron beam welding and cutting exercises. The strikers were released by switching on an electric motor to rotate a pin holding wires retaining the strikers at desired heights. The specimens were suspended so as to be free to respond to the blows with a sudden velocity increment. The specimens were mounted on a hinged plate for minimizing effective mass with the option to fasten it down so as to raise its effective mass closer to that anticipated for an actual space welding scenario. Measurements were made of the impact energy and the horizontal fling distances of

  10. Improving the Fatigue Performance of the Welded Joints of Ultra-Fine Grain Steel by Ultrasonic Peening

    Institute of Scientific and Technical Information of China (English)

    王东坡; 王婷; 霍立兴; 张玉凤

    2004-01-01

    Contrast tests were carried out to study the fatigue performance of the butt joints treated by ultrasonic peening, aiming at the improvement of ultrasonic peening treatment(UPT) on welded joints of a new material.The material is a new generation of fine grain and high purity SS400 steel that has the same ingredients as the traditional low carbon steel. The specimens are in two different states:welded and ultrasonic peening conditions.The corresponding fatigue testing data were analyzed according to the regulation of the statistical method for fatigue life of the welded joints established by International Institute of Welding(IIW). Welding residual stress was considered in two different ways: the constant stress ratio R = 0. 5 and the Ohta method. The nominal stress-number (σ-N)curves were corrected because of the different plate thickness compared to the standard and because there was no mismatch or angular deformation. The results indicated that: 1 ) Compared with the welded specimens, when the stress range was 200 MPa, the fatigue life of the SS400 steel specimens treated by ultrasonic peening is prolonged by over 58 times, and the fatigue strength FAT corresponding to 106 cycles is increased by about 66%; 2) As for the SS400 butt joint ( single side welding double sides molding), after being treated by UPT, the nominal S-N curve (m = 10) of FAT 100 MPa(R =0.5) should be used for fatigue design. The standard S-N curves of FAT 100 MPa ( R = 0. 5, m = 10) could be used for fatigue design of the SS400 steel butt joints treated by ultrasonic peening.

  11. Interdiffusion of Polycarbonate in Fused Deposition Modeling Welds

    Science.gov (United States)

    Seppala, Jonathan; Forster, Aaron; Satija, Sushil; Jones, Ronald; Migler, Kalman

    2015-03-01

    Fused deposition modeling (FDM), a now common and inexpensive additive manufacturing method, produces 3D objects by extruding molten polymer layer-by-layer. Compared to traditional polymer processing methods (injection, vacuum, and blow molding), FDM parts have inferior mechanical properties, surface finish, and dimensional stability. From a polymer processing point of view the polymer-polymer weld between each layer limits the mechanical strength of the final part. Unlike traditional processing methods, where the polymer is uniformly melted and entangled, FDM welds are typically weaker due to the short time available for polymer interdiffusion and entanglement. To emulate the FDM process thin film bilayers of polycarbonate/d-polycarbonate were annealed using scaled times and temperatures accessible in FDM. Shift factors from Time-Temperature Superposition, measured by small amplitude oscillatory shear, were used to calculate reasonable annealing times (min) at temperatures below the actual extrusion temperature. The extent of interdiffusion was then measured using neutron reflectivity. Analogous specimens were prepared to characterize the mechanical properties. FDM build parameters were then related to interdiffusion between welded layers and mechanical properties. Understating the relationship between build parameters, interdiffusion, and mechanical strength will allow FDM users to print stronger parts in an intelligent manner rather than using trial-and-error and build parameter lock-in.

  12. Laser weld process monitoring and control using chromatic filtering of thermal radiation from a weld pool

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Cheol Jung; Kim, Min Suk; Baik, Sung Hoon; Chung, Chin Man

    2000-06-01

    The application of high power Nd: YAG lasers for precision welding in industry has been growing quite fast these days in diverse areas such as the automobile, the electronics and the aerospace industries. These diverse applications also require the new developments for the precise control and the reliable process monitoring. Due to the hostile environment in laser welding, a remote monitoring is required. The present development relates in general to weld process monitoring techniques, and more particularly to improved methods and apparatus for real-time monitoring of thermal radiation of a weld pool to monitor a size variation and a focus shift of the weld pool for weld process control, utilizing the chromatic aberration of focusing lens or lenses. The monitoring technique of the size variation and the focus shift of a weld pool is developed by using the chromatic filtering of the thermal radiation from a weld pool. The monitoring of weld pool size variation can also be used to monitor the weld depth in a laser welding. Furthermore, the monitoring of the size variation of a weld pool is independent of the focus shift of a weld pool and the monitoring of the focus shift of a weld pool is independent of the size variation of a weld pool.

  13. Welding of aluminum with linear ribbon explosives.

    Science.gov (United States)

    Bement, L. J.

    1971-01-01

    A small-scale simplified, parallel plate process of welding aluminum with very small quantities of lead-sheathed linear ribbon RDX explosive is described. The results of the welding of five different alloys, obtained by using this technique, show that the weld strengths are up to 90% of the parent metal tensile strength.

  14. 49 CFR 195.224 - Welding: Weather.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Welding: Weather. 195.224 Section 195.224 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Construction § 195.224 Welding: Weather. Welding must be protected from weather conditions...

  15. 49 CFR 179.400-11 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.400-11 Section 179.400-11...-11 Welding. (a) Except for closure of openings and a maximum of two circumferential closing joints in... subchapter). (d) Each welding procedure, welder, and fabricator must be approved. [Amdt. 179-32, 48 FR...

  16. 49 CFR 179.220-10 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.220-10 Section 179.220-10... Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-10 Welding. (a) All joints... of this subchapter). Welding procedures, welders, and fabricators shall be approved. (b)...

  17. 49 CFR 179.200-10 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.200-10 Section 179.200-10... Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-10 Welding. (a) All joints... W (IBR, see § 171.7 of this subchapter). Welding procedures, welders and fabricators shall...

  18. 46 CFR 154.660 - Pipe welding.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Pipe welding. 154.660 Section 154.660 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR... § 154.660 Pipe welding. (a) Pipe welding must meet Part 57 of this chapter. (b) Longitudinal butt...

  19. 49 CFR 179.100-9 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.100-9 Section 179.100-9... Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-9 Welding. (a) All..., appendix W (IBR, see § 171.7 of this subchapter). Welding procedures, welders and fabricators shall...

  20. Experimental analysis of cut welding in aluminium

    DEFF Research Database (Denmark)

    Dorph, Pernille; De Chiffre, Leonardo; Bay, Niels

    1993-01-01

    Cut welding is a newly developed cold pressure welding process. In the present work, an experimental investigation was carried out analyzing the mechanisms involved in cut welding of a block to a strip. Experiments were carried out in technically pure aluminium. The investigation has involved...