Cracking Reason Analysis of Cr12MoV Steel Die during Spark Cutting

By fracture surface observation, metallographic examination, chemical composition analysis and hardness test, the cracking reason of Cr12MoV steel die during spark cutting process was conducted. The results show that heat treatment induced big residual stress which redistributed during spark cutting was the main reason for the die cracking. Eutectic carbide size was out of limits, which made the die material easy to crack along eutectic carbide, was another reason.