Recent Trends and Challenges in Welding of Automotive Steels

Abstract

The development of modern automotive vehicles with improved environmental, safety and vehicle performance has driven the development of new steel grades that are lighter , safer , greener and more cost effective. As a result, conventional low carbon steels and high strength steels are increasingly replaced with adv anced high strength steels (AHSS) due to their high strength and good uniform elongation. This unique combination in mechanical properties is achieved by carefully designing the microstructure by adding special alloying elements and controlled heat treatments. In automotive manufacturing processes, fusion welding is an important process employed for the joining of steel parts and components. However , the thermal cycle of a welding process destroys the carefully designed microstructure of AHSS. In order to use these materials effectively , it is necessary to have a sound understanding of the influence of weld thermal cycles and alloying additions on the evolution of microstructure in the fusion and heat affected zones. In this paper , the current understanding and recent developments in the welding of current generation advanced high strength steels for automotive applications are discussed. The paper concludes with the assessments and possible solutions to improve the weldability of advanced high strength steels for automotive applications.