12Cr2Mo1钢直角弯头裂纹原因分析

Reason Analysis on Surface Crack in Right-angled Elbow of 12Cr2Mo1 Steel

某厂加工的12Cr2Mo1钢直角弯头表面出现裂纹缺陷并有向内部扩展趋势。本文通过对失效弯头样品的宏观检查、无损检测、夹杂物分析、晶粒度评级、金相检验等试验方法,得出裂纹产生的原因是:弯头材料在加工过程中有过热现象,导致晶粒粗大、晶界弱化,在加工应力作用下致使其沿晶断裂。

A right-angled elbow of 12Cr2Mo1 steel processed by certain plant has surface crack defect with propagation tendency to the inner. The reason of crack initiation was analyzed by some experimental methods such as macroscopic observation, nondestructive detection, inclusion analysis, grain size rating test and metallographic examination to the failure elbow. The resules show that the elbow material has superheat phenomenon during working, and this phenomenon makes the grain growth, grain boundary weak, so it can conduce to material intercrystalline cracking under processing stress.