Effect of Mn content and immersion time on the interaction between H13 tool steel and magnesium alloy

High pressure die-cast (HPDC) magnesium (Mg) alloy components exhibit excellent surface quality and high thin-wall strength, making them widely applicable in the automobiles. However, die soldering defects frequently occur during the HPDC process, significantly compromising component quality and production efficiency. In this study, to addressing the die soldering problem, immersion of H13 steel to different Mg alloy melts were performed to study the effect of manganese (Mn) content and immersion time on interfacial interactions between steel and Mg alloys. The results indicate that Mn addition enhances aluminum (Al) diffusion capability, with both Al and Mn diffusion distances progressively increasing over time. Furthermore, the interfacial intermetallic compound (IMC) area at the H13 steel/Mg-6Al, Mg-6Al-0.25Mn, Mg-6Al-0.45Mn, and Mg-6Al-0.7Mn (wt.%) alloy interfaces increases with higher Mn content and extended immersion time, particularly exhibiting significant growth at 0.45 wt.% Mn. Intermetallic compounds (IMCs) formation at the interface may contribute to die soldering in Mg alloy die casting, where Mn addition promotes IMC formation and increases soldering susceptibility.