82B盘条断口典型形貌及产生原因分析

利用扫描电镜和光学显微镜对82B盘条典型断口样的形貌及夹杂物进行观测和对用4%(质量分数)硝酸酒精侵蚀的金相样的表面质量和心部组织进行分析。结果表明，造成黑心白点断口异常断裂的原因是熔渣卷入形成的大颗粒夹杂；脆性平齐断口断裂主要是由心部马氏体、网状渗碳体及边部增碳组织等不良组织和夹杂物造成的；斜茬状横裂纹断口断裂主要是由于组织存在马氏体和铸坯中存在有缩孔；劈裂断口主要是由于碳偏析造成的；而笔尖断口主要是由于组织中的人字微裂纹和网状渗碳体组织造成的。

Analysis on typical morphology of tensile fracture and broken reason of 82B wire rod

Typical morphology of tensile fracture and non- metallic inclusion in 82B wire rod were observed and detected, and surface quality and central structure of corroded metallographic specimen were inspected by means of scanning electric microscope (SEM) and optical microscope. Results show that the broken reason for the black center with white point fracture was the big slag inclusion; the broken reason for the plane shaped fracture was core martensite, central network cementite, border local carburetion and non- metallic inclusions; the broken reason for the cross section of chrysanthemum fracture was the core martensite and shrinkage cavity in central porosity; the broken reason for the split fracture was the carbonic segregation; the broken reason for the pencil- tip shaped fracture was the inversed V- type micro cracks and network cementite.