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基于第二相Ostwald熟化的相关理论,对5炉成分有细微差别的20CrMnTi渗碳齿轮钢中Ti(C,N)在930℃下的粗化规律进行了计算.结果表明,在930℃渗碳温度下分别保温1、2、4、8、16h,随着保温时间的延长,各炉钢中碳氮化钛颗粒均会发生一定程度的粗化,第二相的粗化速率系数m值越大,粗化行为越严重.在保温8h时,t时间后第二相的平均尺寸dt变化范围为2.64～16.2nm,最大偏差在13nm左右;保温16h时,dt变化范围为3.33～20.4nm,最大偏差约为17nm,表明Ostwald熟化作用对Ti(C,N)第二相颗粒尺寸的影响不大.对钉扎奥氏体晶界、阻止奥氏体晶粒长大起主要影响作用的是第二相颗粒的初始尺寸.
Based on the related theory of Ostwald ripening in the second phase, the roughening rules of Ti (C, N) in 20CrMnTi carburized gear steel with five different compositions were calculated at 930 ℃. The results show that carburizing at 930 ℃ 1, 2, 4, 8 and 16h respectively. With the prolongation of holding time, some carbonitrides in the furnace steels would be roughened to a certain extent. The coarsening rate coefficient m of the second phase Large, rough behavior more serious.Under 8h, the average size of the second phase after t time dt ranged from 2.64 to 16.2nm, the maximum deviation of about 13nm; insulation 16h, dt range of 3.33 ~ 20.4nm, The maximum deviation is about 17 nm, indicating that the Ostwald ripening effect has little effect on the grain size of the second phase of Ti (C, N). The main effect on the grain boundary of the pinned austenite and preventing the grain growth of austenite The initial size of the second phase particles.