中碳微合金化钢高温延塑性的研究  

Research on Hot Ductility of Medium Carbon Microalloyed Steel

作　　者：龚雅林[1] 张炯明[1] 甄新刚[1] 陈少东[1] 姚永宽 王道远 

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]南京钢铁集团中厚板卷厂,江苏南京210035

出　　处：《钢铁》2010年第6期67-73,共7页Iron and Steel

基　　金：国家自然科学基金与宝钢联合资助项目(50774109)

摘　　要：借助Gleeble1500热模拟试验机测试了含Nb和含Nb、Ti两种中碳微合金化钢的高温力学行为,分析了析出物、相变、动态再结晶对微合金化钢高温延塑性的影响。结果表明：试验钢种无第Ⅱ脆性区出现;含Nb钢第Ⅲ脆性区的温度范围为950-700℃,含Nb、Ti钢第Ⅲ脆性区的温度范围为900-725℃;微合金化元素Ti的加入可以细化奥氏体晶粒使含Nb微合金化钢高温塑性槽变窄、变浅;析出物沿晶界多而细小的析出和γ→α相变是第Ⅲ脆性区微合金化钢高温延塑性变差的主要原因。实际生产中通过优化二冷区水量,采用弱冷,可以有效降低微合金化钢表面微裂纹的发生率。High temperature mechanical behaviors of Nb and Nb, Ti containing steel were tested by Gleeble1500 thermal simulation testing machine. Meanwhile, influences of precipitate, phase change and dynamic recrystallization on hot ductility of the micro-aHoy steel were also analyzed. The results demonstrate that the brittle zone Ⅱ does not exist. The temperature range of brittle zone Ⅲ is about 950-700℃ in Nb containing steel and 900-725 ℃ in Nb, Ti containing steel. The addition of micro-alloying element Ti can refine austenite grains thus the hot ductility trough of Nb containing steel becomes narrow and shallow. Both precipitations along the grain boundaries and during γ→α phase transformation are main factors which lead to a decrease on hot ductility of Nb and Nb, Ti containing steel. In the practice process the incidence of surface micro-cracks in micro-alloying steel can be reduced dramatically by decreasing specific water rate in secondary cooling zone.

关 键 词：微合金化钢 连铸 高温延塑性 表面微裂纹 

分 类 号：TF762.3[冶金工程—钢铁冶金]