challenges in weldability of advanced high strength automotive steels during resistance spot welding

Advanced high strength steels (ahss) have become increasingly important in the automotive industry due to their high strength-to-weight ratio and excellent energy absorption capabilities. however, their complex chemical compositions and multiphase microstructures present significant challenges in resistance spot welding (rsw), which remains the dominant joining method in body-in-white assembly. this review identifies and analyzes the key weldability challenges of ahss, including metallurgical issues such as martensite formation and heat-affected zone softening, mechanical performance limitations related to nugget size and failure modes, process-related difficulties such as electrode wear, expulsion, and narrow welding windows, as well as liquid metal embrittlement (lme) in coated steels. furthermore, the challenges become more pronounced in dissimilar and third-generation ahss joints due to differences in thermal, electrical, and mechanical properties. potential strategies to mitigate these issues are discussed, including optimization of welding parameters, tailored welding schedules, improved electrode design, and selection of steels with enhanced weldability. the insights presented in this review provide a comprehensive understanding of ahss weldability and support the development of reliable, high-performance spot welds in next-generation automotive applications