Showing papers on "Electric resistance welding published in 2014"
TL;DR: In this article, the welding nugget can be considered as aluminum matrix composite, which is enhanced by dispersed sheared-off steel fragments encompassed by a thin inter-metallic layer or simply intermetallic particles.
243 citations
TL;DR: A comprehensive survey of welding processes used to deposit wear resistant overlays is presented in this paper, based on both literature review and research work performed at the Canadian Centre for Welding and Joining.
173 citations
TL;DR: In this article, it was demonstrated that the strength of the nugget could be increased by the use of a higher strength interlayer during friction stir welding, however, this strength recovery cannot be attainable in the heat affected zone.
Abstract: Although sound AA6061-T6 joints can be produced by friction stir welding, a loss in strength takes place in the weld region. In this study, it was demonstrated that the strength of the nugget could be increased by the use of a higher strength interlayer during friction stir welding. This strength recovery cannot, however, be attainable in the heat affected zone. Although an external cooling was applied during welding in order to increase strength in the heat affected zone, it was not sufficient for achieving the required cooling condition for improved strength.
132 citations
TL;DR: In this article, an optimization of ultrasonic spot welding parameters for joining 3003 Aluminum alloy with 304 Stainless steel was performed at various clamping pressures and energy levels for investigating its effect on microstructure, mechanical properties and bond quality of the weld.
121 citations
TL;DR: In this paper, the effect of the processing parameters on the weld bead geometry was examined, and the microstructure and mechanical properties of the optimal joint were investigated, showing that the focal position is a key parameter in high power fiber laser welding of thick plates.
116 citations
TL;DR: In this article, a three-dimensional turbulent steady state numerical model was used to investigate the influence of an alternating current (AC) magnetic field during high power laser beam keyhole welding of 20mm thick stainless steel AISI 304 being modeled as an ideal non-ferromagnetic material.
107 citations
TL;DR: In this article, the authors investigated the welding deformation in low carbon steel thin-plate joints induced by laser beam welding and CO 2 gas arc welding by means of both numerical simulation technology and experimental method in the current study.
107 citations
TL;DR: In this article, the ability to relate weld strength to the welding process data, namely dissipated power and displacement of the sonotrode, in ultrasonic welding of thermoplastic composite parts with flat energy directors, is described.
Abstract: Ultrasonic welding of thermoplastic composites is a very interesting joining technique as a result of good quality joints, very short welding times and the fact that no foreign material, e.g. a metal mesh, is required at the welding interface in any case. This paper describes one further advantage, the ability to relate weld strength to the welding process data, namely dissipated power and displacement of the sonotrode, in ultrasonic welding of thermoplastic composite parts with flat energy directors. This relationship, combined with displacement-controlled welding, allows for fast definition of optimum welding parameters which consistently result in high-strength welded joints.
106 citations
TL;DR: In this article, the effect of welding current at constant welding time was considered on the weld properties such as weld nugget size, tensile-shear load bearing capacity of welded materials, failure modes, failure energy, ductility, and microstructure of weld nuggets as well.
102 citations
TL;DR: In this article, five different tool designs have been employed to analyse the influence of rotation speed and traverse speed over the microstructural and tensile properties of dissimilar AA2024 and AA6061 aluminium plates of 5mm thickness.
99 citations
TL;DR: A review of research progress on aluminum-steel dissimilar welding is presented in this article, where current issues and recent developments in improving the intermetallic compound layer of weld joint are critically assessed.
Abstract: This paper presents a review of research progress on aluminum–steel dissimilar welding. Current issues and recent developments in improving the intermetallic compound layer of weld joint are critically assessed. Several welding factors that improve joint quality, such as welding method, weld and material preparations, as well as welding parameters, are also discussed. This study also examines recent developments in hybrid welding techniques and proposes a preheating method to enhance the weld joints of aluminum–steel dissimilar welding.
TL;DR: In this article, a three dimensional laser deep penetration welding model in which volume of fluid (VOF) method was combined with a ray tracing algorithm was used to simulate the dynamic coupling between keyhole and molten pool in laser full penetration welding.
TL;DR: In this paper, the microstructural properties, tensile properties and low-cycle fatigue properties of a dual-phase steel (DP780) were investigated following its joining by three methods: laser welding, tungsten inert gas (TIG) welding, and metal active gas (MAG) welding.
TL;DR: In this paper, nominal friction stir [butt] welding process parameters for joining 4.76mm-thick aluminum alloys 6061-T6 and 7075t6 were established.
Abstract: The objective of this work is to establish nominal friction stir [butt] welding process parameters for joining 4.76-mm-thick aluminum alloys 6061-T6 and 7075-T6 and to improve the joint quality via programmed tool offsets. In addition, dynamic tool–workpiece interface temperatures are measured during welding and used to explain the effects of alloy placement and weld tool offset from the joint. Weld tool offsets into the retreating side AA7075 increase the measured tensile strength of the dissimilar joint. The increased joint strength is facilitated by lower average weld temperatures with increasing amount of AA7075 stirred into the nugget.
TL;DR: In this article, the microstructure of the fusion zone and the heat affected zone is investigated in resistance spot welding of AISI 430 ferritic stainless steels and the phase transformations which occur during weld thermal cycle were analyzed in details, based on the physical metallurgy of welding of the ferritic steels.
TL;DR: In this article, an underwater friction stir welding is carried out in order to reduce heat input comparing with traditional friction-stir welding and further improve the joint performances by varying welding temperature history by comparing the thermal cycle curves and distribution of residual stress of the plate welded in different media.
TL;DR: In this paper, a preliminary investigation of the through-thickness 2D residual stresses distributions, distortions, and plastic strain characteristics, for the narrow gap laser welding (NGLW) process using material thicknesses up to 20mm.
TL;DR: In this paper, a two-pass laser welding procedure was introduced for dissimilar joining of overlapped galvanized high-strength dual-phase (DP) steel DP590 to aluminum alloy (AA) 6061 sheets.
TL;DR: In this article, three welding speeds designated as low (1.5mm/s), medium (2.5 mm/s) and high (3.5 millimeters/sec) were operated during gas tungsten arc welding (GTAW) process and joints made were subjected to analysis of the microstructures, mechanical and corrosion properties of the joints.
TL;DR: In this paper, a continuous drive friction welding of aluminium to copper for defense applications was studied and the microstructural characterization of the weld interface was analyzed by optical and scanning electron microscopy and X-ray diffraction analysis technique.
TL;DR: In this article, the fatigue characteristics of a tensile shear specimen during spot welding was investigated with the welding parameters that occur in the surface crack of welds on Zn-coated steel.
Abstract: The development of the automotive industry is now focused not only on improving basic vehicle performance but also on reducing weight and enhancing safety and durability. Various automotive high-strength steels are being developed, and Zn-coated steels are being manufactured to prevent corrosion of the external white vehicle body. The most commonly used welding method in the car body assembly process is resistance spot welding (RSW), which has been extensively studied worldwide. In this process, the work piece is basically heated according to the contact resistivity of the interfacial between the electrode and the material as well as the bulk resistivity of the material itself. At this point, if the meta li s Zn, which has a lower melting point than the Fe base metal on the surface, it is mainly melted in the temperature range of 400900°C. It becomes easy to penetrate the grain boundary of the HAZ during welding. Also, the tensile stress in such a state decreases the ductility of the grain boundary and causes liquid metal embrittlement (LME). Cu5Zn8, an intermetallic compound, can be formed from the reaction of the alloy with the Cu material electrode in the expulsion current range at a high temperature. Its formation is likely to be facilitated by LME or a surface crack. In this study, the fatigue characteristics of a tensile shear specimen during spot welding was investigated with the welding parameters that occur in the surface crack of welds on Zn-coated steel. Finally, a controlled spot welding condition was suggested to prevent surface cracks. [doi:10.2320/matertrans.M2013244]
TL;DR: In this paper, the influence of the balance of current between the TIG and MIG arcs was investigated, which is most important in determining arc stability and arc penetration, and it was shown that the welding time can be reduced to 17 ~ 44 % of the time required using a conventional TIG process.
Abstract: Tungsten inert gas (TIG) and metal inert gas (MIG) welding are the most popular gas-shielded arc-welding processes used in many industrial fields. MIG welding is a high-efficiency process compared to TIG welding. However, improvements are needed to reduce spatter and improve weld metal toughness. Although pure argon shielding gas is desirable for weld metal toughness, MIG arcs are unstable in pure Ar to the extent that executing welding is difficult. We have found that MIG arcs become stable even using pure argon by simply using a hybrid TIG and MIG system. This process has the possibility of becoming a new welding process giving high quality and efficiency. In this study, we investigate the influence of the balance of current between the TIG and MIG arcs, which is most important in determining arc stability and arc penetration. We have confirmed the suitable range of conditions both experimentally and through numerical simulation and have applied this process for butt and fillet joints. We show that the welding time can be reduced to 17 ~ 44 % of the time required using a conventional TIG process.
TL;DR: In this article, a self-support friction stir welding (SSFSW) tool with a big concave upper shoulder and a small convex lower shoulder was developed for making reliable welds in aluminum hollow extrusion.
TL;DR: In this article, the effects of the RSW parameters on weld properties were investigated within a design of experiments framework by altering the electrical current intensity, welding time, sheet thickness, electrode face radius, and squeeze force at multiple levels.
TL;DR: In this article, an experimental work with pulsed Nd:YAG laser was performed for dissimilar welding of Ti-6Al-4V and Nitinol and the results indicated that insertion of copper interlayer has a great influence on the reduction of the amount of Ti 2 Ni brittle intermetallic phase, elimination of transverse cracks through the weld metal and eventually improvement of mechanical properties of the joints.
TL;DR: In this article, a microstructure and property evaluation of friction stir welded low alloy steel grade DH36 plate, commonly used in ship and marine applications has been undertaken, and a preliminary process parameter envelope has been developed and initial process parameter sets established that produce commercially attractive excellent quality welds through a substantial increase in the conventionally recognised weld traverse speed.
TL;DR: In this paper, the effect of welding speed on the quality of a lap weld joint in the Al and Cu sheets with a single mode fiber laser was investigated and it was found that sound strong weld joints could be produced by suppressing the formation of intermetallic compounds in the interface zone at extremely high speeds.
Abstract: Conventional fusion welding of aluminium and copper dissimilar materials is difficult because of poor weldability arising from the formation of brittle intermetallic compounds on the weld zone as well as different chemical, mechanical and thermal properties of welded joints. Joining of Al and Cu plates or sheets offers a metallurgical challenge due to unavoidable formation of brittle intermetallic compounds. Therefore, it is necessary to effectively suppress the formation and growth of Al–Cu intermetallic compounds. For welding of dissimilar Al and Cu sheets, no systematic work has been conducted to reduce these defects. Thus, this paper focuses on the effect of welding speed on the quality of a lap weld joint in the Al and Cu sheets with a single mode fibre laser. It was found that consequently sound strong weld joints could be produced by suppressing the formation of intermetallic compounds in the interface zone at extremely high speeds.
TL;DR: In this paper, experiments were made for welding current variation between 6kA and 12kA, and the effect of welding current on micro-properties was very slight while nugget size was highly dependent on welding current.
TL;DR: In this article, the authors summarized the current understanding of the bonding mechanism and the structure in various similar and dissimilar metal pairs joined by magnetic pulse welding (MPW) and proposed two major ideas based on either solid state bonding or local melting and solidification.
Abstract: Magnetic pulse welding (MPW) is a solid-state impact welding technology that provides metallurgical joints while exhibiting a negligible heat-affected zone. The MPW process is a high speed single shot welding technique used mainly for joining tubular components in a lap configuration and characteristic length scales of few millimeters to centimeters. It is similar in operation to explosive welding and shares the same physical principles. The nature of bonding in MPW is not sufficiently understood yet and some controversial explanations are reported in the literature. The two major ideas are based on either solid state bonding or local melting and solidification. The present work summarizes our current understanding of the bonding mechanism and the structure in various similar and dissimilar metal pairs joined by MPW.
TL;DR: In this paper, the effect of external magnetic field (EMF) on the RSW process of aluminum alloy under different welding parameters has been studied and the effects of the EMF on weld size, tensile shear force, microstructure, and microhardness have been systematically discussed.