600～1200℃高Nb、Ti微合金钢高温热塑性研究  

Study on the Hot Ductility of High Nb and Ti Micro-alloyed Steel

作　　者：梁文 胡俊[1] 刘文艳[1] Liang Wen;Hu Jun;Liu Wenyan(Wuhan Branch of Baosteel Central Research Institute,Wuhan 430080,Hubei,China;Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China)

机构地区：[1]宝钢股份中央研究院武汉分院,湖北武汉430080 [2]武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室,湖北武汉430081

出　　处：《钢铁钒钛》2019年第3期124-130,141,共8页Iron Steel Vanadium Titanium

基　　金：国家自然科学基金(No.51771139)

摘　　要：采用光学显微镜、扫描电镜、透射电镜以及显微硬度仪对高Nb、Ti微合金钢的高温热塑性拉伸试样进行检测。结果显示,高Nb、Ti微合金钢在600~1200℃的断面收缩率呈“V”形;在800℃时断面收缩率最小,在1200℃断面收缩率达到最大值。其第Ⅲ脆性区间为680~910℃,脆化的主要原因是大尺寸碳氮化物和先共析铁素体在晶界析出,弱化了晶界结合力,为裂纹的产生和扩展提供了条件。而试样中普遍存在的微米级TiN颗粒,是造成高Nb、Ti微合金钢断面收缩率整体偏低的主要原因。提高应变速率,缩短先共析铁素体析出和TiN颗粒长大的时间,减弱拉伸过程中的应力集中,可改善试样在第Ⅲ脆性区间的高温热塑性。The hot ductility of high Nb and Ti micro-alloyed steel had been investigated through the high temperature tensile test and optical microscopy,scanning electron microscopy,transmission electron microscopy and micro-hardness tester.The results show that the relationship between the rate of reduction in area and the temperature range from 600~1 200 ℃ was V-shape for the high Nb and Ti micro-alloyed steel.The rate of reduction in area was the lowest at 800 ℃ while that was the highest at 1 200 ℃.The third brittle zone for the high Nb and Ti micro-alloyed steel was 680~910 ℃.The main reason for the embrittlement was the large-size carbonitrides and pro-eutectoid ferrite precipitated at the grain boundaries which weakened the grain boundary bonding force and provided conditions for crack generation and expansion.The micron-sized TiN particles in the sample were the main reason for the low rate of reduction in area of the high Nb and Ti micro-alloyed steel.The hot ductility at the third brittle zone can be improved by increasing the strain rate,shortening the time for the precipitation of pro-eutectoid ferrite and the growth of TiN particles and weakening the stress concentration during the tensile test.

关 键 词：高Nb、Ti微合金钢 高温热塑性 碳氮化物 先共析铁素体 应变速率 

分 类 号：TF777[冶金工程—钢铁冶金]