Nb-V微合金钢凝固过程的热塑性  

Hot ductility of Nb-V containing microalloyed steel during solidification

作　　者：孙彦辉[1] 赵勇[1] 曾亚南 宋方圆[1] 

机构地区：[1]北京科技大学钢铁共性技术协同创新中心,北京100083 [2]华北理工大学冶金与能源学院,河北唐山063009

出　　处：《材料热处理学报》2016年第2期128-134,共7页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51274032)

摘　　要：通过理论计算和热模拟试验对Nb-V微合金钢的热塑性进行了研究,并考察了微观偏析和析出物粒子对热塑性的影响。结果表明,S、P和O元素偏析主要发生在糊状区（固液两相区）,同时树枝晶间Fe（S,O）和（Fe,Mn,Si,Al）（S,O）类夹杂物的形成导致了热塑性恶化。在1000～975℃区间,Nb N粒子直径由20 nm减小到10 nm,粒子数量由23个/μm2上升到45个/μm2,断面收缩率迅速由82.36%下降到69.61%;在900～850℃区间,断面收缩率缓慢下降并伴随有铁素体膜逐渐变厚。温度小于975℃、高临界应力下容易发生晶间断裂,从而产生裂纹源。Hot ductility of Nb-V-containing steel was studied by theoretical calculation and thermal simulation experiments, and effect of microsegregation and precipitates on hot ductility was studied. The results show that segregation degrees of elements S, P and O are greater in mushy zone, while, the hot ductility is deteriorated by inclusions of Fc（ S, O）and （Fe, Mn, St, A1） （S, O） in the interdendritic regions. In the temperature range from 1000 ℃ to 975 ℃ , reduction of area rapidly decreases from 82.36% to 69.61% , the diameters decrease from 20 to 10 nm and quantity of particles increase from 23 to 45 inds/μm2 , respectively. In the temperature range of 900 ℃ to 850 ℃, the reduction of area reduces slowly with ferrite films thickening gradually. Intergranular fracture is easy to occur with higher critical stress below 975 ℃.

关 键 词：溶质偏析 脆性区 低应变速率 析出物 临界应力 

分 类 号：TG115.5[金属学及工艺—物理冶金]