摘要
通过扫描电镜、能谱和低倍组织观察,分析了20Mn钢中外折、推方裂、硬点和掉块等4类主要缺陷的形成原因。结果表明,外折主要为水口结瘤物脱落和结晶器卷渣形成的夹杂物进入铸坯,在穿管时椭圆度过大受力不均造成的;推方裂主要形成原因为热处理时出现上贝氏体组织,内含脆性通道在加工变形时易断裂;硬点为废钢带入的含Cr或W的难熔金属所致;Mn元素在铸坯的宏观偏析恶化了铸坯轧制力学性能,造成掉块。
The forming causes of four main quality defects such as outer fold, cracks, hard spot and block loose in 20Mn2 steel were analyzed by scanning electron microscopy, energy disperse spectroscopy and optical microscopy. The results show that, the outer fold results from the inclusions in the nozzle blockage and slag in the mould mixed in the liquid steel; the cracks results from the upper bainite formed in heat treatment easy breaking under stress; the hard spot results from the refractory metal Cr and W in liquid steel brought with steel scrap; the block loose results from the macro segregation of manganese element.
出处
《铸造技术》
CAS
北大核心
2013年第10期1302-1305,共4页
Foundry Technology
基金
国家自然科学基金资助项目(51074019)
关键词
20MN2钢
外折
硬点
质量缺陷
20Mn2 steel
outer fold
hard spot
quality defects
