冷却模式对0.1%C-5%Mn钢的铸坯组织及内部裂纹的影响

Effect of cooling model on slab structure and internal crack of 0.1%C-5%Mn steel

为了揭示0.1%C-5%Mn钢的板坯内部裂纹的产生机理,采用物理测试、金相分析和设计热模拟试验等方法,研究了不同冷却模式下钢的组织及裂纹特征。结果表明,高的冷却强度下铸坯内部出现了大量的马氏体和裂纹,冷却强度越大马氏体相越多,裂纹宽度越大。采用缓冷或热送的工艺能够防止快速冷却引起的马氏体相变,形成粒状贝氏体组织,由此可以控制内部裂纹的产生和扩展。

In order to reveal formation mechanism of slab internal crack of the 0.1%C-5%Mn steel, structure and crack feature of this steel have been researched under different cooling models by using methods such as physical test, metallographic examination etc and designing heat simulation experiment. The results show that a lot of martensite and crack appeared in the slab when the cooling intensity was high.The higher the cooling intensity, the more martensite phase had and the greater the crack width. By using soft cooling or hot charging process, the martensite transformation caused by rapid cooling could be prevented and granular bainite structure could be formed, which could control appearance and extension of the internal crack.