40Cr钢棒材剪切开裂原因

Reason for shear cracking of 40Cr steel bars

某公司生产的40Cr钢棒材在冷剪切下料过程中发生开裂。采用宏观观察、化学成分分析、扫描电镜分析、金相检验等方法分析了该棒材开裂的原因。结果表明:棒材表面局部存在加工硬化层,导致棒材发生了剪切开裂;加工硬化层的产生原因是棒材在精整过程中,矫直及砂轮扒皮工艺不当。

A certain company produced 40Cr steel bars that cracked during the cold shear cutting process.The cause of cracking in the bar was analyzed using methods such as macroscopic observation,chemical composition analysis,scanning electron microscopy analysis and metallographic examination.The results show that there was a localized work hardening layer on the surface of the bar,which led to shear cracking of the bar.The reason for the formation of work hardening layer was improper straightening and grinding wheel peeling process during the finishing process of the bar.