【摘要】 利用热模拟实验,对在非再结晶温度变形后弛豫一段时间,再以不同冷速冷却的低碳贝氏体钢的相变组织进行了研究,并与同等条件不弛豫的试样组织进行了对比.给出了弛豫和冷速对中温转变组织类型及组织细化程度的影响.实验结果表明,弛豫及冷却速度对变形奥氏体的相变组织是有影响的.低冷速下主要得到边界及取向不清晰的粒状贝氏体,这时弛豫时间对细化程度影响不明显,在10℃/S以上冷速下得到的是以板条贝氏体为主的组织,与未弛豫试样比较,其组织更细,板条形状更清晰,弛豫试样组织中残余奥氏体或M/A岛的形状更细长,弛豫有利于在同等冷却条件下得到板条组织,并且在高冷速下,弛豫试样中M/A量较未弛豫试样中的要少.更多还原

【Abstract】 The intermediate transformation microstructure of low-carbon bainite steel was analyzed, which hadbeen deformed in the non-recrystallization temperature range, relaxed for a period of time and cooled by variouscooling rates. The influence of relaxation process and cooling rate on the intermediate transformation structure typeand microstructure refinement was revealed. The results show that in a slowly cooled sample after relaxation thetransformation structure is mainly granular bainite and the effect of relaxation refinement is not marked. But whilethe cooling rate is fast enough (>10℃/s), the main microstructure is lath-like bainite, and relaxation effect can beseen clearly After relaxation, the lath of bainitic ferrite is more fine and sharp, the morphology of M/A constituentis film-like. Comparing with the non-relaxed sample, it is clearly seen that the relaxation of deformed austenite ben-efits to obtain ultra-fine lath-like bainite structure. At the same cooling rate, the amount of M/A constituent decrea-ses in the relaxed sample.更多还原