摘要
采用金相检测、SEM、TEM、能谱、水口流场分析等方法，并通过对连铸坯热成像温度分析，对S355ML异形坯表面横裂纹产生原因进行研究。结果表明：直通型水口流场分布不合理；异形坯表面存在较大的温度梯度，特别是从翼缘顶端到腹板R角处，异形坯在矫直段处于铸坯脆性区；并且在S355ML异形坯大量析出碳氮化物破坏钢的高温热塑性，从而使铸坯裂纹敏感性增加。通过优化二冷制度，窄成分控制等措施，矫直时避开铸坯第Ⅲ脆性区，提高铸坯表面质量。
The causes of surface transverse crack on $355ML beam blanks had been investigated by met- allographic, SEM, TEM observations and nozzle flow field analysis, in combination with thermal imaging temperature of continuous casting billet. Results show that the flow field distribution of through-type noz-zle is unsuitable. The surface of beam blank flange to the web R Angle, thus profiled billet exist great temperature gradient, especially from top of fall in brittle zone during straightening. Furthermore, lots of carbonitride precipitation in S355ML shaped blank damage high temperature ductility of steel, and thus increase the slab crack sensitivity. By optimizing secondary cooling system and controlling composition at narrow range , the billet can be avoided to fall in Ⅲ brittle zone when being straighten and then slab surface quality can be improved.
作者
赵鹏泽
孙彦辉
董健
吴保桥
王厚昕
Zhao Pengze1, Sun Yanhui2, Dong Jian2, Wu Baoqiao3, Wang Houxin4(1. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 10（1083, China; 2. Collaboration Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083, China; 3. Ma＇ anshan Iron and Steel Co. , Ltd. , Ma＇ anshan 24300, Anhui, China; 4. CITIC Metal Co. , Ltd. , Beijing 100004,China)
出处
《钢铁钒钛》
CAS
北大核心
2018年第1期136-142,共7页
Iron Steel Vanadium Titanium
基金
中信微合金化技术中心资助项目“-50℃耐低温Nb微合金化热轧H型钢开发与工程应用”的支持
关键词
连铸
异形坯
表面横裂纹
第Ⅲ脆性区
continuous casting ,beam blank, surface transversal crack, the HI brittle zone
