Cause Analysis of Weld Crack of Automobile Body Steel
Car body steel is one of the common problems in machining process.The microstructure and mechanics of the weld crack specimen is analyzed.The crack reason has been found,and the corresponding improvement measures are put forward.The results show that the metallographic structure and mechanical properties of the base metal are not the main reasons for the weld crack.The Widmanstatten microstructure in the weld area caused by improper welding process is the main reason for weld crack.By reducing the welding current and increasing the upsetting distance,the toughness and elon-gation of the weld are ensured,thus avoiding the cracking of the weld.