40Mn2圆钢热顶锻开裂原因分析

The Analyses on Hot Forging Surface Cracking of 40Mn2 Hot Rolled Barstock

本文针对40Mn2圆钢1/3热顶锻严重开裂问题,运用高倍显微镜、扫描电镜、能谱仪等检测设备,结合钢坯低倍酸洗,从坯到材系统分析,综合分析发现造成圆钢表面裂纹的重要原因是钢坯存在皮下裂纹、柱状晶较发达等低倍缺陷。为冶炼生产工艺优化提供依据,从而实现40Mn2批量稳定生产。

In this article,the reasons of severe surface cracking of 40Mn2 hot rolled barstock during 1/3 hot forging test were analyzed with metallographic microscope,SEM,energy spectrometer and acid etching,etc.By the analyses of casting billet,intermiediate products and hot rolled barstocks,the major reasons of surface cracks were found which were subsurface cracks and over-developed columnar crystals in casting billitet.The analyses of this article provided basis for smelting process improvment,and finnaly realized stable mass production of 40Mn2 hot rolled barstocks.