Wheel steel products of Han Steel occurred welding cracking when using in a wheel factory,by analyzing the crack in the wheel steel weld cracking with microstructure analysis and spectrum analysis,test results showed the grain in heat affect zone serious grow,and the user at the end of the flash-butt quenched from a high temperature to room temperature at welding seam,larger cooling rate to generate sufficiently large quenching stress,increased the risk of cracking along the grain boundary.When the stress reaches a certain level,there will be a greater area of the grain cracks at the location of welding seam,eventually leading to weld cracking.We develop measures for improvement to solving this problem,we suggest that the cooling mode at welding seam should be slow cooling or air cooling after the rim welding process,welding current range is 7800~9500 amps,upsetting time is 0.2 seconds,these measures can improve the welding quality of wheel steel products and reduce the risk of welding cracks.