scispace - formally typeset
Search or ask a question
Topic

Spot welding

About: Spot welding is a research topic. Over the lifetime, 12491 publications have been published within this topic receiving 89845 citations. The topic is also known as: Spot_welding.


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, the microstructure and mechanical characteristics of spot welded specimens, fabricated from low carbon steel sheets with different microstructures, were studied and a cross section cut through the spot weld reveals a similar grain size and phase distribution in the nugget on both the sides of the initial interface between sheets.
Abstract: We studied the microstructure and mechanical characteristics of spot welded specimens, fabricated from low carbon steel sheets with different microstructures. Both ultra-fine grained (UFG) steel sheet and coarse grained (CG) steel sheet were used. The refined microstructure of the UFG steel has been produced by severe plastic deformation (SPD) using the constrained groove pressing (CGP) method. The grain size of the base metals was approximately 260 nm and 30 µm in diameter, respectively, in the UFG and CG steels. Examining the microstructure of a cross section cut through the spot weld reveals a similar grain size and phase distribution in the nugget on both the sides of the initial interface between sheets. Some recrystallization is observed in the heat affected zone on the UFG side as previously reported after the welding of symmetrical UFG–UFG spot welded specimens. The same energy deposit produces larger nuggets after the spot welding of UFG steels. Moreover, the hardness distribution across the nugget changes after welding on both sides of the initial (UFG/CG) interface. This effect is presently attributed to a change in the solidification, cooling rate and tempering after welding, likely because the higher resistance of UFG steel sheets increases the heat release by the Joule effect during spot welding. These changes in the mechanical behavior modify the transition between the interfacial failure (IF) and pull out failure (PF) mode with respect to energy deposit.

28 citations

Journal ArticleDOI
02 Sep 2011
TL;DR: In this article, the failure loads of a friction stir spot welding (FSSW) joint of two aluminum alloy 6061-T6 sheets under specific loading cases were predicted using the finite element method.
Abstract: Failure loads of a friction stir spot welding (FSSW) joint of two aluminum alloy 6061-T6 sheets under specific loading cases were predicted using the finite-element method. The detailed modelling technique of a FSSW joint using available experimental data is presented in this paper. The characteristics and dimensions of different zones of the FSSW joint including the stir zone (SZ), heat-affected zone (HAZ), thermal-mechanically affected zone (TMAZ), and base metal (BM) were obtained from literature. The mechanical properties calculated from a relation between the measured hardness values and the corresponding strengths for each zone were then applied to the failure prediction model. In this model the ESI–Wilkins–Kamoulakos (EWK) rupture model of the PAM-CRASH commercial software was employed to verify the case of the lap-shear tension test. The failure load obtained in this model showed a good agreement with the experimental value in the reference. The failure prediction for the other loading cases (peel...

28 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of tool rotational speed and tool stirring (dwell) time on the weld structure and static strength of welds was evaluated, and the results revealed that the width of the completely metallurgical-bonded region increases with the increasing tool rotation and/or the dwell time up to certain levels.
Abstract: In the present investigation, friction stir spot welding on annealed aluminum alloy AA5754 sheets was performed. The influences of the tool rotational speed and tool stirring (dwell) time on the weld structure and static strength of welds were evaluated. The results revealed that the width of the completely metallurgical-bonded region increases with the increasing tool rotational speed and/or the dwell time up to certain levels. Increasing such parameters beyond these levels slightly reduces the width of the bonding region. The stirred zone exhibited higher microhardness than that of the base material. The tensile-shear force was found to increase with the increasing tool rotational speed and/or dwell time up to a certain level (9s). Higher tool rotational speeds and/or prolonged dwell times slightly reduce(s) the tensile-shear force.

28 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present an experimental study relating to the simultaneous estimation of RTC and α at the electrode/sheet interface during the resistance spot welding process, and the results of measurement of t...
Abstract: The numerical simulation of the resistance spot welding process requires a precise understanding of the thermal conditions at the electrode/sheet interface. This necessitates a knowledge of the thermal contact resistance RTC which prevails at the interface, and the partition coefficient of generated heat flux at the interface α. This coefficient draws its significance from the non-conservative character of the generated heat flux in the disturbed zone of the contact. Consequently, on the macroscopic scale, only a fraction α (α< 1) of the heat flux generated at the interface contributes to the temperature change at the electrode/sheet interface. The present work reports an experimental study relating to the simultaneous estimation of RTC and α at the electrode/sheet interface during the resistance spot welding process. Both parameters, RTC and α, depend on the electrode/sheet interface structure. Consequently, RTC and α are time dependent during the welding process. The results of measurement of t...

28 citations

Journal Article
TL;DR: In this article, the residual stresses of spot welds were calculated using a nonlinear finite el- ement analysis (FEA), and the calculated residual stresses were compared to those measured by X- ray diffraction.
Abstract: This paper presents a method for fatigue strength assessment of spot welds, which incorporates the effects of welding residual stress. Residual stress analysis with a welding thermal history was evaluated first, and then stress analy- sis for fatigue was performed. First, the residual stresses of spot welds were calculated using a nonlinear finite el- ement analysis (FEA). To validify the FEA results, the calculated residual stresses were compared to those measured by X- ray diffraction. The residual stress distrib- utions showed good agreement between calculations and measurements. Then, to evaluate the fatigue strength of spot welds, stress analyses were performed under ten- sile loading on various dimensions and shapes of spot welds. Based on the results, the stress ampli- tude ((Ya-res)' which took into considera- tion welding residual stress at the nugget edge of a spot weld, was calculated using a modified Goodman equation. Using the stress amplitude (Ya-res at the nugget edge, the load range (AP)-fatigue life (Nf) rela- tions from the fatigue tests can be re- placed by the Ga.re s -Nf relations. It was found the proposed stress am- plitude (Ga_res) provided a systematic and accurate evaluation of fatigue strength of spot-welded joints with various dimen- sions and shapes.

28 citations


Network Information
Related Topics (5)
Welding
206.5K papers, 1.1M citations
91% related
Alloy
171.8K papers, 1.7M citations
84% related
Microstructure
148.6K papers, 2.2M citations
83% related
Deformation (engineering)
41.5K papers, 899.7K citations
82% related
Machining
121.3K papers, 1M citations
81% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023208
2022415
2021355
2020620
2019739
2018744