High rate impact welding of aluminum/galvanized steel: interface formation and effects

Galvanized steel has been widely used in industrial fields such as automobiles, ships, and household appliances. Due to its anti-corrosion properties, galvanized steel samples have lower corrosion rates and toughness losses. Therefore, using galvanized steel sheets is an effective way to improve the quality of welded joints. Nowadays aluminum alloy is gradually replacing steel as the raw material for industrial products due to its lightweight and corrosion-resistant properties, aluminum alloys have disadvantages in terms of cost and mechanical properties. Multi-material structures in industrial products (especially in automotive components) to fully utilize the advantages of steel and aluminum alloys. There are many ways to achieve steel/aluminum dissimilar metal connections. Due to the high welding temperature and poor welding environment, a high volume fraction of Al-Fe-Si intermetallic compounds precipitates at the welding interface, resulting in higher hardness at the welded joint and strong local corrosion. High-speed impact welding can effectively avoid these problems. At low welding temperature and high impact speed, minimal metal melting occurs at the interface while the base material deforms in solid state, forming a characteristic wavy bond morphology. Therefore, the coating will affect the morphology and component content of the welding interface during the impact joining process. In this paper, the effects of Zn coating on the welding interface will be investigated and the joint interface formation process will be clarified by using a method that combines numerical simulation and experiment, in order to instruct the processing design.