Impact of liquid metal embrittlement inner cracks on the mechanical behavior of 3rd generation advanced high strength steel spot welds

Abstract

Controlled degradation of the welding parameters is used in this work to produce homogeneous advanced high strength steel (AHSS) resistance spot welds with significant liquid metal embrittlement (LME) inner cracks and study their impact on mechanical behavior. For the first time, the effect of LME inner cracks on damage development is monitored using interrupted cross tension and tensile shear test. Despite their potential effect on the stress state at the notch tip, the observed LME inner cracks seldom contribute to the final fracture path of the welds, leaving the load bearing capacity and failure type of the welds mostly unaffected in tensile shear or even increased in cross tension.

Keywords

• Automotive steels
• Resistance spot welding
• Liquid metal embrittlement
• Type C LME cracks
• Cross tension
• Tensile shear