Welding Metallurgy of
01 Jan 1987-
About: The article was published on 1987-01-01 and is currently open access. It has received 991 citations till now. The article focuses on the topics: Welding.
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TL;DR: In this paper, a comparative study of the tubular wire and clad electrode processes was carried out, looking at the mechanical and micro-structural properties of weld metals of high-resistance steel, in the "as-welded" and "stress-relief heat treatment" (PWHT) conditions.
Abstract: A comparative study of the clad electrode and tubular wire processes was carried out, looking at the mechanical and micro-structural properties of weld metals of high-resistance steel, in the ‘as-welded’ and ‘stress-relief heat treatment’ (PWHT) conditions. The results show that the procedures adopted for welding with tubular wire and clad electrodes allow satisfactory levels of mechanical resistance to be obtained, with the exception of the value of percentage lengthening of the tubular wire, in the as-welded condition. The impact tests show that both the weld metals showed satisfactory impact resistance, in both the as-welded and PWHT conditions, observing that, for the tubular wire, the impact resistance is lower for the clad electrode in both conditions, lying close to the limit applied for the acceptance criterion of 50 J at 0°C in the PWHT condition. It was confirmed that the productivity achieved by the tubular wire process was approximately twice as high as that for the clad electrode process. As ...
15 citations
TL;DR: In this article, the influence of welding procedures (sequence, welding direction and reverse pass) and transfer modes (MAG-CC, MAG-STT and MAG-CW) on distortion values was investigated.
Abstract: With the growth of the Brazilian shipbuilding industry, problems from the production processes emerged in the form of distortions and residual stresses. This study researched the influence of welding procedures (sequence, welding direction and reverse pass) and transfer modes (MAG-CC, MAG-STT and MAG-CW) on distortion values. All of the welds were performed with ER70S-6 wire and pure CO2 shielding gas in the short-circuit mode. It was observed that the most important variable was change of welding direction, which is directly connected to restriction levels of the test panel. The sequences used showed little effect on the distortion values. The reverse pass had low distortion values, yet was unproductive. It was observed that the distortion values were similar for the processes and MAG-STT. The panels welded by the MAG-CW process obtained the lowest distortion values measured.
15 citations
TL;DR: In this article, the authors investigated the mechanical properties and microstructure of friction stir butt welded high strength/ductility multilayered steel consisting of 15 alternating layers of SUS 301 austenitic stainless steel (eight layers) and SUS 420J2 martensitic steel (seven layers) with a total thickness of 1·2 mm.
Abstract: This study investigates the mechanical properties and microstructure of friction stir butt welded high strength/ductility multilayered steel consisting of 15 alternating layers of SUS 301 austenitic stainless steel (eight layers) and SUS 420J2 martensitic stainless steel (seven layers) with a total thickness of 1·2 mm. With optimised welding parameters, defect free welds with an ultimate tensile strength (UTS) of 1240 MPa and a fracture elongation of 13% were accomplished. This corresponds to a joint efficiency of 90%. In this case, fracture occurred in the heat affected zone as a result of a very pronounced hardness drop in the martensitic layers resulting from the formation of a large amount of grain boundary precipitates, which were formed at temperatures ∼750°C slightly below Ac1. By applying post-weld heat treatment, the hardness drop in the martensitic layers was removed and the tensile properties were enhanced to UTS of 1310 MPa (95% joint efficiency) and a fracture elongation of 22%.
15 citations
Cites background from "Welding Metallurgy of"
...Conventional fusion welding methods would certainly destroy the laminated structure due to melting by creating a rather undefined alloy.(13) The FSW process, in contrast, provides solid state welding and thus less impact on the joining material....
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TL;DR: In this paper, electron beam welding of a binary Ti/Ni dissimilar metal couple was performed and the results showed that microstructures near the fusion interfaces are markedly different from those inside the weld region.
Abstract: We present results for electron beam welding of a binary Ti/Ni dissimilar metal couple. The difference in physical properties of the base metals and metallurgical features (thermodynamics and kinetics) of the system influence both macroscopic transport and microstructure development in the weld. Microstructures near the fusion interfaces are markedly different from those inside the weld region. At the Ti side, Ti2Ni dendrites are observed to grow toward the fusion interface, while in the Ni side, layered growth of γ-Ni, Ni3Ti, and Ni3Ti + NiTi eutectic is observed. Different morphologies of the latter eutectic constitute the predominant microstructure inside the weld metal region. These results are compared and contrasted with those from laser welding of the same binary couple, and a scheme of solidification is proposed to explain the observations. This highlights notable departures from welding of similar and other dissimilar metals such as a significant asymmetry in heat transport that governs progress of solidification from each side of the couple, and a lack of unique liquidus isotherm characterizing the liquid–solid front.
14 citations
Cites result from "Welding Metallurgy of"
...This is in direct contrast with typical solidification microstructures in similar metal welding where dendrites advance into a weld metal under a positive temperature gradient near the fusion interface (‘‘constrained’’ mode of dendrite growth).([31]) To understand this departure from conventional weld solidification, we first note that Ti2Ni is the lowest melting phase in the Ti-Ni system which forms by a peritectic reaction at 1257 K (984 C)....
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TL;DR: In this article, a coupled experimental and numerical study on FHPP of ASTM A36 steel is presented to understand the effect of processing conditions on the joint structure and properties, where axi-symmetric heat transfer analysis is carried out to compute the temperature field.
Abstract: Friction hydro pillar processing (FHPP) is a novel technique to fill in crack-holes in thick-walled metal structures by an external stud and forming a solid-state bond between the stud and the metal substrate. During the process, the stud is rotated against the crack-wall to facilitate friction heating and flow of plasticized material for proper filling of the crack-hole. We present here a coupled experimental and numerical study on FHPP of ASTM A36 steel to understand the effect of processing conditions on the joint structure and properties. An axi-symmetric heat transfer analysis is carried out to compute the temperature field. The computed thermal cycles are used to estimate the hardness distribution across the joint. The estimated thermal cycles and hardness distribution are tested with the corresponding experimentally measured results.
14 citations
Cites background from "Welding Metallurgy of"
...A quantitative knowledge of peak temperature and thermal cycles could provide a measure of the joint properties during welding of alloys [13]....
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References
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TL;DR: In this article, the state of the art in selective laser sintering/melting (SLS/SLM) processing of aluminium powders is reviewed from different perspectives, including powder metallurgy (P/M), pulsed electric current (PECS), and laser welding of aluminium alloys.
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TL;DR: In this article, the authors show that the pre-existing dislocation network, which maintains its configuration during the entire plastic deformation, is an ideal modulator that is able to slow down but not entirely block the dislocation motion.
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TL;DR: In this article, the fundamental understanding of structure-properties relationship in automotive steels resistance spot welds is discussed. And a brief review of friction stir spot welding, as an alternative to RSW, is also included.
Abstract: Spot welding, particularly resistance spot welding (RSW), is a critical joining process in automotive industry. The development of advanced high strength steels for applications in automotive industry is accompanied with a challenge to better understand the physical and mechanical metallurgy of these materials during RSW. The present paper critically reviews the fundamental understanding of structure–properties relationship in automotive steels resistance spot welds. The focus is on the metallurgical characteristics, hardness–microstructure correlation, interfacial to pullout failure mode transition and mechanical performance of steel resistance spot welds under quasi-static, fatigue and impact loading conditions. A brief review of friction stir spot welding, as an alternative to RSW, is also included.
369 citations
TL;DR: In this article, a unified equation to compute the energy density is proposed to compare works performed with distinct equipment and experimental conditions, covering the major process parameters: power, travel speed, heat source dimension, hatch distance, deposited layer thickness and material grain size.
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