Analysis of Resistance Spot Welding (RSW) on 22MnB5 material after hot stamping for automotive applications (B-pillar)

Abstract

One of the major concerns that arose in recent years within the automotive industry has been making cars sustainable, safe and economic. One of the ways to solve this equation is to use lighter materials that reduce the weight of vehicles and increase the energy absorption mainly on the B-pillar. This paper aims to study the RSW cycle of the welding parameter known as P1. The parameter were defined to reach the maximum load during the tensile test according to the norm AWS D8.9. The test samples were assembled with a GAP to reproduce real vehicle welding conditions, and the parameter P1 weld 22MnB5 steel samples with heat treatment, known as Press Hardening Steel (PHS). The influence of these parameters on the PHS mechanical properties was evaluated with Vickers hardness test (HV), metallographic technique, conducting ultrasonic and tensile test. The results confirmed the difference at the Heat affected zone (HAZ) mechanical strength over fusion zone. It was possible to visualize a softening region in the HAZ and increasing to the weld point, which is demonstrated in the microstructural analysis and thus justifies the detachment of the weld button of the base material in tensile test. Keywords: PHS, HAZ, RSW.