Enhancing nugget size and weldable current range of ultra-high-strength steel using multi-pulse resistance spot welding

Abstract

This paper presents an innovative approach that uses a pulse-profile to improve the welding quality of CP1180 steel in resistance spot welding process. Three pulses with two cooling times were used in the developed multi-pulse welding (MPW) schedule. The experimental results show that the first pulse increases the contact area between the sheets to improve the current flow pattern. The second pulse was designed to extend the sheet-to-sheet contact area and corona bond for preventing rapid nugget growth. Using these designs, the nugget size was maximised through the third pulse. The maximum nugget size using the designed MPW schedule was 18.5% greater than that of the single-pulse welding schedule and the weldable current range was extended by 130%.

Double Pulse Resistance Spot Welding of Dual Phase Steel: Parametric Study on Microstructure, Failure Mode and Low Dynamic Tensile Shear Properties

“…The FZ size depends upon the amount of heat generated during RSW. The physical principal for achieving the heat generation in the RSW process is defined by Joule’s heating equation given below [ 32 ]. where is the heat generated (J), is the current applied (A), is the total resistance (Ω) and is the time for which current is applied (s).…”

“…The FZ size depends upon the amount of heat generated during RSW. The physical principal for achieving the heat generation in the RSW process is defined by Joule's heating equation given below [32].…”

Liquid metal embrittlement during the resistance spot welding of galvannealed steels: synergy of liquid Zn, α-Fe(Zn) and tensile stress

“…In the automobile industry, resistance spot welding (RSW) is a fusion welding process that is used to assemble steel sheets; in this process, the heat required for melting is produced by passing high current through copper electrodes [4][5][6]. However, Zn coating is prone to liquid metal embrittlement (LME) cracking during RSW [7][8][9][10][11].…”

Prediction of the Shear Tension Strength of Resistance Spot Welded Thin Steel Sheets from High- to Ultrahigh Strength Range

“…RSW welding process can be easily automated [14,15], robotized, therefore RSW is also an optimal process for mass production. RSW is also one of the most used welding process in car body manufacturing.…”

“…Recently, extensive research hase been done in the field of the application of different pulsed welding technologies in the case of HSS welding. Kim et al [15] investigated different pulse profiles to improve the weld quality of CP1180 steel. They have found that the volume of the weld nugget can be increased by pulse welding, and the weldable current range can be extended compared to single pulse welding.…”