Study on Welding Technology and Microstructure and Properties of Ultra-high Strength Dual-phase Steel for Automobile

Abstract

In the background of energy saving and environmental protection, the lightweight of automobile is the goal of its development .The use of ultra-high strength steel as the structural parts and safety parts of car body is to ensure the lightweight of automobile under the premise of ensuring the safety of the car. In order to improve the vehicle safety and save the cost, the welding process of ultra-high strength steel should be optimized continuously. As ultra-high strength steel, DP steel is in common use for bodywork. When they are welded by spot welding, laser welding, MAG and CMT welding, the heat input and welding speed should be controlled so as to prevent the occurrence of burn through and incomplete welding. DP steel reduced the generation of tempered martensite while welding, they will be able to obtain the welding joints with good hardness and strength. CMT welding technology of DP steel is the development trend of automotive sheet welding.