Abstract: The  dissolution  and  precipitation  of Nb-Ti  carbides  in  austenite  of  a  low  carbon  microalloying  steel (0.09C,1.42Mn,0.035Nb,0.012Ti)have   been   analyzed   by   theoretical   calculation   method,and   the   austenite   grain   size  with different heating temperature and the hardness of steel after solid solution treatment -aging were examined. The results  showed that Nb-Ti carbide completely dissolved at  1060 ℃ and almost Nb and Ti in austenite precipitated in the form of  NbC and TiC at 800 ℃ aging. At 700 ℃ aging the Nb-Ti carbides precipitated in ferrite,and with decreasing temperature  the carbides precipitation decreased. The hardness of steel was up to maximum value as aged at 600 ℃.

Key words: Nb-Ti Microalloying Steel,Carbide,Dissolution,Precipitation

摘要： 采用理论计算方法分析了Nb、Ti碳化物在低C微合金钢(%:0.09C、1.42Mn、0.035Nb、0.012Ti)奥氏体中的溶解与析出,测试了不同加热温度下奥氏体晶粒尺寸以及固溶-时效后实验钢的硬度。结果表明,Nb、Ti碳化物在1060℃全部溶解,800℃时效时,奥氏体中的Nb、Ti基本以NbC、TiC形式析出。700℃时效时,Nb、Ti碳化物在铁素体内析出,随温度降低,碳化物析出减慢。600℃时效,钢的硬度达到最大值。

关键词: Nb-Ti 微合金钢, 碳化物, 溶 解 , 析 出