Effect of Liquid Metal Embrittlement Indent Cracks on Zinc Coated 3rd Generation AHSS Mechanical Performance

Third-generation advanced high-strength steels (3G-AHSS) are typically galvanized to prevent corrosion of the outer body structure. However, zinc coating on surface, combined with locally elevated temperatures generated during resistance spot welding (RSW) process, can provide prerequisites for liquid metal embrittlement (LME). This work uses two strategies control LME crack formation: current pulsation and varying electrode geometry. These methods were compared a baseline schedule 3G-980-GI coated AHSS. The effectiveness each method was discussed in terms overall weld cracking index local index. results showed that increasing pulses slower energy input into weld, which help reduce formation. Introducing more (five seven pulses) reduced formation while maintaining same time. Regarding geometry, an increase currents below expulsion level Imax-10% when face diameter increased, whereas at Imax-200A, radius most important factor For above expulsion, Imax+10%, drastic decrease observed large surface used. not significant controlling LME. mechanical properties selected conditions examined using lap shear test no effect cracks tensile strength. location failure indicated located indented area (type A), does influence