Abstract: To ensure the good weldability between 20Cr steel and cast steel of level B, the welding tests with different welding processes for quenched 20Cr steel and cast steel of level B were carried out to analyze cold/thermal crack sensitivities of welded joints. The results showed that welding between positioning pin of quenched 20Cr steel and axle housing of Level B cast steel with electrode J502, J506, A302 and welding wire ER50-6 was feasible, and the welded joints had good performance of cold/thermal crack resistance. However, more attention should be paid to the welding parameters.