回火温度对Ti-V-Mo复合微合金钢组织及硬度的影响  

Effect of tempering temperature on microstructure and hardness of Ti-V-Mo complex microalloyed steel

作　　者：王茹玉[1] 赵时雨 张可 裴英豪[1] 李景辉 张明亚 WANG Ru-yu;ZHAO Shi-yu;ZHANG Ke;PEI Ying-hao;LI Jing-hui;ZHANG Ming-ya(Maanshan Iron and Steel Co.,Ltd.,Ma′anshan 243000,Anhui,China;School of Metallurgical Engineering,Anhui University of Technology,Ma′anshan 243002,Anhui,China)

机构地区：[1]马鞍山钢铁股份有限公司,安徽马鞍山2430002 [2]安徽工业大学冶金工程学院,安徽马鞍山243032

出　　处：《钢铁研究学报》2020年第12期1132-1140,共9页Journal of Iron and Steel Research

基　　金：国家自然科学基金资助项目(51704008);国家重点研发计划资助项目(2017YFB0305100,2017YFB0304700);钒钛资源综合利用国家重点实验室开放基金资助项目(18100009);国家重点基础研究计划资助项目(2015CB654803)。

摘　　要：利用OM、SEM、TEM、EBSD和维氏硬度计等手段研究了回火温度对Ti-V-Mo复合微合金钢组织转变及硬度的影响,探讨了(Ti,V,Mo)C在不同回火温度下的析出规律及其对硬度的作用机制。结果表明,在450~600℃回火时,随着回火温度的升高,硬度呈直线上升趋势,在600℃回火时硬度具有最大值450HV。随着回火温度的升高,试验钢马氏体板条块宽度由7.3μm增大至9.9μm,600℃回火时析出相粒子的平均尺寸为5 nm,10 nm以下的(Ti,V,Mo)C粒子可高达90%,理论计算沉淀强化增量导致硬度上升90.7HV,远高于基体软化造成的硬度损失,因而析出强化是影响Ti-V-Mo复合微合金钢硬度的主要因素。在600~650℃回火,大小角度晶界分布比例基本相同,马氏体板条块的平均尺寸变化不大,但是析出相的平均尺寸由5 nm提高到5.6 nm,尺寸小于5 nm的(Ti,V,Mo)C粒子所占比例逐渐下降,导致硬度下降。The effect of tempering temperature on the microstructure evolution and hardness of Ti-V-Mo complex microalloyed steel was studied by means of OM, SEM, EBSD, TEM and Vickers hardness tester. The precipitation law of(Ti, V, Mo)C at different tempering temperatures and the mechanism of its effect on hardness were explained. The results show that the hardness of(Ti, V, Mo)C increases linearly when tempering temperature is 450-600 ℃. Maximum hardness can reach 450 HV when tempering temperature is 600 ℃. When the tempering temperature at 650 ℃, the hardness decreases slightly. Meanwhile the average grain size of martensite lath block in Ti-V-Mo complex microalloyed steel increases from 7.3 to 9.9 μm. The amount of(Ti, V, Mo)C increases monotonously, while the average size of precipitated phase particles at 600 ℃ is 5 nm, and(Ti, V, Mo)C particles below 10 nm can be as high as 90%. The theoretical calculated precipitation strengthening increment leads hardness to increase by 90.7 HV, which was much higher than the hardness loss caused by the softening of the matrix. Thus, the main factor to the increase in hardness of Ti-V-Mo complex microalloyed steel is refinement mean size of(Ti, V, Mo)C particles. Tempered at 600-650 ℃, the distribution ratio of grain boundaries is basically the same, the average size of martensite laths changes slightly, but the average size of precipitated is increased from 5 to 5.6 nm, and the proportion of(Ti, V, Mo)C particles less than 5 nm gradually decreases, resulting in a decrease in hardness.

关 键 词：回火温度 Ti-V-Mo 硬度 析出规律 (Ti V Mo)C 

分 类 号：TG142.33[一般工业技术—材料科学与工程] TG156.5[金属学及工艺—金属材料]