Application of High Strength Hot Rolled Steel to DC Butt Rim Welding

The characteristics of DC butt welding of high strength hot rolled steel was studied in relation to the production of wheel rims. A thermal distribution analysis of DC butt welding indicated the importance of the optimization of welding condition as the maximum temperature attained in DC butt welding significantly differed from place to place along the welding line. Insufficient heat input or overheating might cause cold weld or solidification cracking. Particularly,the welding current and welding cycle should be strictly controlled in order to make a weld with good cold formability. The influence of steel chemistry on weld hardness was also investigated. High strength steel for DC butt rim welding should be produced with the least Ceq. because a relatively early stage bead trimming enhances hardenability of the weld,which increases sensitivity to cracking.