Heat evolution and nugget formation of resistance spot welding under multi-pulsed current waveforms

2020 ◽  
Vol 111 (11-12) ◽  
pp. 3583-3595
Author(s):  
Yaqiong Wang ◽  
Zhenghua Rao ◽  
Fengjiang Wang
Author(s):  
Zhijun Wu ◽  
Guanlin Zhang ◽  
Bingxu Wang ◽  
Kelvin Shih

Resistance Spot Welding (RSW) is one of the most common and dominant technologies utilized in the automotive industry to join the thin sheet metals together, and expulsion is a common phenomenon during the operation. How to ensure the high quality nugget formation and joining performance is essential to ensure the quality and integrity of structures. In this study, solid state resistance spot welding is introduced in order to prevent expulsion. The effect of welding current and welding time on the mechanical performance of the solid state RSW in terms of nugget size, tensile performance and nugget formation will be investigated experimentally by using steel sheet metals. Microstructure and micro-hardness of the nugget cross-section will be evaluated as well.


2021 ◽  
Author(s):  
Mercedes Pérez de la Parte ◽  
Alejandro Espinel Hernández ◽  
Mario César Sánchez Orozco ◽  
Angel Sánchez Roca ◽  
Emilio Jiménez Macias ◽  
...  

Abstract This paper researches the effect of zinc coating of galvanized DP600 steel on the dynamic resistance and the delayed nugget formation of dissimilar DP600 - AISI304 welded joints, obtained with resistance spot welding process (RSW). The RSW evaluations consisted of determining, from the dynamic resistance curves, the time involved in the different stages of the process, particularly the beginning of nugget formation. The experimental results showed that, from the dynamic resistance curves, it is possible to identify 8 distinct stages during the welding of galvanized DP600 steel and AISI304 stainless steel. In the case of the welding of uncoated DP600 steel with AISI304, only 6 stages are identified (except for stages 2 and 3), which are directly related to the heating, softening and melting of the galvanic coating. The energy used in stages 2 and 3, causes a delay in the beginning of nugget formation for welded joints obtained with galvanized DP600 steel compared to uncoated DP600 - AISI304 welded joints, reaching values between 37.28 ms and 52.29 ms for the welding conditions analyzed. Monitoring the time duration of stages 2 and 3, as defined from the analysis of the dynamic resistance curves, could be used as a tool to predict the beginning of nugget formation in the welding of galvanized steels, to avoid undesirable phenomena such as expulsion and to guarantee the quality of the welded joints.


2015 ◽  
Vol 80 (5-8) ◽  
pp. 1137-1147 ◽  
Author(s):  
J. Sagüés Tanco ◽  
C. V. Nielsen ◽  
A. Chergui ◽  
W. Zhang ◽  
N. Bay

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