第3代汽车钢板坯角部横裂纹形成机理  

Formation mechanism of slab corner transverse crack of the third generation automobile steel

作　　者：陶红标[1] 张慧[1] 王明林[1] 范倚[1] 马忠伟[1] 赵沛[1] 

机构地区：[1]钢铁研究总院连铸技术国家工程研究中心,北京100081

出　　处：《炼钢》2015年第3期69-73,共5页Steelmaking

基　　金：国家"973计划"项目"夹杂物稳定性及铸坯均匀度控制的研究"(2010CB630806)

摘　　要：为了探明第3代汽车钢板坯角部横裂纹的产生机理,采用数学计算、物理测试、金相分析等方法,类比分析了第Ⅲ脆性区温度范围下钢的热膨胀系数、热塑性、相变特征以及第二相析出行为。结果表明,奥氏体晶界铁素体膜和AlN的析出是降低钢的高温延展性的内因,板坯边角部过冷是促发角部横裂纹产生的外因,而低温下的多次相变和(Mn,Fe)3C的析出会进一步提高钢的裂纹敏感性,由此提出了角部横裂纹的控制措施,实现了约250 t钢的全流程生产。In order to reveal formation mechanism of slab corner transverse crack of the third generation automobile steel, analogy analysis on the thermal expansion coefficient, thermoplasticity, phase change feature and the second phase precipitation behavior in the scope of the third brittle zone temperature had been carried out by using methods such as mathematical calculation, physical test, metallographic examination etc. The results showed that precipitation of ferrite film and AlN on the austenitic grain boundary should be the internal reason for reducing steel high temperature ductility. Supercooling imposed on slab edge should be the external reason for promoting corner transverse crack. Besides, multiple phase change and precipitation of （Mn, Fe）3 C in low temperature would increase the crack sensitivity of this steel at further. Based on this research, the controlling measures for corner transverse crack had been put forward and the whole process production for about 250 t steel had been realized.

关 键 词：第3代汽车钢 角横裂 AlN过冷 铁素体膜 第Ⅲ脆性区 

分 类 号：TF762[冶金工程—钢铁冶金]