Study on the thermo-effect of nugget growing in single-phase AC resistance spot welding based on the calculation of dynamic resistance

Luo, Yi; Wan, Rui; Zhu, Yanan; Xie, Xiangyu

doi:10.1016/j.measurement.2015.09.034

Cited by 14 publications

(4 citation statements)

References 24 publications

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“…As the resistance forms at the interface between two sheets of metal, heat is evolved from the joint as the current is applied, however, melting, and consequent solidification of the resistance spot weld forces the initial solidification front to undergo the formation of the columnar grain structure as the current is no longer available. The edges of the weld zone transform from a near-delta ferrite structure and cools faster just after the current is cut off, forming a heat affected zone (HAZ) of coarse and then fine grain structures (Song et al, 2005;Rogeon et al, 2008;Luo et al, 2016). The thickness of Zn rich layer formed on the uncoated cap due to the Zn coating on steel is around 6 µm (Fig.…”

Section: Microstructural Analysis and Microhardness Results Of Resist...mentioning

confidence: 99%

Performance of resistance spot weld caps coated with Ni and Fe aluminide alloys by electro spark deposition on hot dip galvanized steel

Açış

Talaş

2023

revmetal

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Resistance spot welding (RSW) is widely used as a main joining technique in industry and the electrode caps are frequently replaced because of the degradation during service. In this study, the G type copper RSW electrode caps were coated with Fe and Ni based Fe3Al, FeAl, Ni3Al, NiAl alloys by Electro-Spark Deposition (ESD), providing resistance to hot deformation, oxidation and Zn evaporation from sheet metal. The ESD coated electrode caps were tested in-situ on a hot dip galvanized steel in order to assess the performance of RSW electrode caps. For this purpose, three different coating voltages were selected for each coated electrode, and 12 different cap coatings were produced in total. Fifty resistance spot welds were consecutively manufactured with the same parameters for each type of coating electrodes. Hardness measurements, macrostructural examination, Ultrasonic Testing (UT) and chisel tests were performed on welded samples produced. In addition, effects of different coatings on RSW electrode caps were investigated on microstructural development, hardness variations and deformation capacity of resistance spot welds. Results showed that chisel tests and cross section thickness values of the welded sample made with the caps that were ESD coated with the Ni3Al electrode produced better results than the other caps. The cross-sectional thickness of nuggets was lower in all 158 V coated caps. The performance of aluminide coatings on RSW electrode caps can be listed from the best to the worst in the order of Ni3Al, NiAl, Fe3Al, and FeAl.

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Section: Microstructural Analysis and Microhardness Results Of Resist...mentioning

confidence: 99%

Performance of resistance spot weld caps coated with Ni and Fe aluminide alloys by electro spark deposition on hot dip galvanized steel

Açış

Talaş

2023

revmetal

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“…Additionally, rapid heating and cooling combined with phase transformations during cooling contribute to these stresses [4,5]. As a result, welding introduces complex residual stresses that act as an artificial physiochemical change [6,7]. Two key factors, weld nugget size and residual stresses, have the most significant impact on the mechanical behavior of the RSW joint.…”

Section: Introductionmentioning

confidence: 99%

A review of microstructure, residual stresses, and mechanical performance for the welding spot of the alloy steel

2024

MJET

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Spot welding joins various steel types across diverse applications. Notably, it plays a crucial role in automotive manufacturing, where over 5000 spot welds contribute to the structural integrity of each car. This complex process relies on heat and pressure to create "nuggets" of melted metal that bond the sheets together. However, the rapid heating and cooling involved induce significant changes in the material's microstructure, mechanical properties, and residual stresses. These stresses arise from non-uniform expansion and contraction during welding, as well as from phase transformations due to localized heating and cooling. This study delves into these microstructural changes, residual stresses, and mechanical behaviors of spot welds. Additionally, it investigates how welding parameters like current, time, and force influence the joint's strength and residual stresses.

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“…Kang Zhou et al [19] found that the electrical resistivity of the molten nugget was theoretically and experimentally deduced, according to detailed theoretical analyses based on the principle of electrical resistivity and the resistance spot welding process. Yi Luo et al [20] calculated the dynamic resistance based on the welding current and electrode voltage detected in resistance spot welding and studied the thermal effects of nugget growth during nugget forming. The growth process of nuggets in resistance spot welding can be divided into three stages.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Continuous Melting and Secondary Contact Melting in Resistance Heating Metal Wire Additive Manufacturing

et al. 2020

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Resistance heating metal wire materials additive manufacturing technology is of great significance for space environment maintenance and manufacturing. However, the continuous deposition process has a problem in which the metal melt is disconnected from the base metal. In order to study the difference between the second contact melting of the disconnected metal melt and the continuous melting of the metal wire as well as eliminate the problem of the uneven heat dissipation of the base metal deposition on the melting process of the metal wire, the physical test of melting the metal wire clamped by the equal diameter conductive nozzle was carried out from the aspects of temperature distribution, temperature change, melting time, dynamic resistance change, and the microstructure. The current, wire length, and diameter of the metal wire are used as variables. It was found that the dynamic resistance change of the wire can be matched with the melting state. During the solid-state temperature rise, due to the presence of the contact interface, the continuous melting and secondary contact melting of metal wires differ in dynamic resistance and the melting process. The continuous melting of the metal wire was caused by the overall resistance of the wire to generate heat and melt, and the temperature distribution is “bow-shaped”. In the second contact melting, the heat generated by the contact interface resistance was transferred to both ends of the metal wire to melt, and the temperature distribution is “inverted V”. The microstructure of the metal wire continuous melting and secondary contact melting solidification is similar. The continuous melting length of the metal wire is greater than the melting length of the secondary contact.

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Study on the thermo-effect of nugget growing in single-phase AC resistance spot welding based on the calculation of dynamic resistance

Cited by 14 publications

References 24 publications

Performance of resistance spot weld caps coated with Ni and Fe aluminide alloys by electro spark deposition on hot dip galvanized steel

Performance of resistance spot weld caps coated with Ni and Fe aluminide alloys by electro spark deposition on hot dip galvanized steel

A review of microstructure, residual stresses, and mechanical performance for the welding spot of the alloy steel

Mechanism of Continuous Melting and Secondary Contact Melting in Resistance Heating Metal Wire Additive Manufacturing

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