奥氏体高温转变区二段冷却速率对铁素体相变的影响  

Effect of Two-stage Cooling Rate on Austenite-ferrite Phase Transformation in High Temperature Transition Region

作　　者：彭宁琦[1] 唐广波[1] 刘正东[1] 

机构地区：[1]钢铁研究总院结构材料研究所,北京100081

出　　处：《材料工程》2013年第9期11-15,共5页Journal of Materials Engineering

基　　金：国家"十一五"科技支撑计划项目(2006BAE03A08)

摘　　要：采用Gleeble热力模拟机对C-Mn钢热压缩变形后过冷奥氏体高温转变区进行二段冷却速率控制,通过冷却过程中施加微小应变,并根据应力-温度曲线,结合金相组织观察,研究了二段冷却速率对铁素体相变开始温度和相变组织的影响。结果表明:在过冷奥氏体高温转变区冷却相同时间,相对于连续冷却,当前段快冷,后段缓冷时,铁素体相变开始温度下降,相变的铁素体体积分数增加;当前段快冷速率为100℃/s时,铁素体相变开始温度下降幅度能达到100℃,铁素体体积分数增加近1倍。因此,应用前置式超快冷,并随后缓冷的冷却方式有助于提高铁素体转变量,并降低铁素体相变的温度,以细化铁素体晶粒。Effects of different two-stage cooling rates on start temperature and microstructure of ferrite transformation were studied with metallographic microstrueture, stress-temperature curves and small strains in the cooling process. The two-stage cooling rate of C-Mn steel in high-temperature transition zone of deformed austenite was controlled by Gleeble thermal mechanical simulator. The results show that ferrite transformation start temperature drops and ferrite volume fraction increases when this way of front fast cooling and subsequent slow cooling at the high temperature transformation zone of su- percooled austenite, compared with the same time continuous cooling, and when rapid cooling rates of 100℃/s in the preceding stage, decline of ferrite transformation start temperature can reach 100℃ and ferrite volume fraction is nearly double. Therefore, the cooling way of front ultra fast cooling （UFC） and subsequent slow eooling is helpful to enhance amount of ferrite transformation and reduce ferrite phase transition temperature in order to refine the ferrite grain.

关 键 词：冷却速率 铁素体 相变 超快冷 

分 类 号：TG111.6[金属学及工艺—物理冶金]