低碳贝氏体钢不同冷却速度下的组织结构研究  

Microstructure of low carbon bainite steel at different cooling rate

作　　者：关云[1] 李平和[1] 刘继雄[1] 陈庆丰[1] 吴立新[1] 

机构地区：[1]武汉钢铁(集团)公司研究院,武汉430080

出　　处：《中国体视学与图像分析》2009年第3期245-251,共7页Chinese Journal of Stereology and Image Analysis

摘　　要：对低碳贝氏体钢进行热模拟实验,在非再结晶区变形后以不同的冷却速度冷却,研究了不同冷却速度下低碳贝氏体钢的组织结构特征和第二相析出规律。结果表明,冷却速度对组织亚结构的影响较大。以20~50℃/s的高速冷却后,该钢的组织以板条贝氏体为主,小角度晶界较多。随着冷却速度的降低,组织中板条贝氏体减少,粒状贝氏体增加,大角度晶界比例增加,但板条间取向差极小。当冷速降低到5℃/s时,粒状贝氏体的体积分数显著增多,并形成有明显取向差的胞状亚晶。以3℃/s冷却后,组织以粒状贝氏体为主,出现先共析铁素体晶核,开始发生铁素体相变;以低于2℃/s的冷速冷却后,形成由块状铁素体、多边形铁素体和粒状贝氏体组成的混合组织,大角度晶界比例较高。实验钢中的析出相主要有矩形（Ti,Nb）（N,C）及球形Nb（N,C）或NbC两种,在冷却过程中,以NbC相析出为主,随着冷却速度降低,析出相尺寸略有增大。Based on the results of thermal simulation test, the microstructure and precipitated phase of low carbon bainite steel treated at different cooling rate was studied. The results indicate that the cooling rate greatly influences the microstructure of steel. At cooling rate of 20 -50℃/s, the main microstructure is lath bainite. With reducing cooling rate, lath bainite reduced as well as granular bainite increased. The TEM test showed that there are two types of precipitated phases in this steel, one is rectangular （Ti, Nb） （ N, C） , another is spherical Nb （ N, C ） or NbC. The main second phase is NbC in the cooling procedure, and the size of the precipitated phase is slowly increased as the cooling rate is reduced.

关 键 词：冷却速度 贝氏体 组织结构 析出相 低碳贝氏体钢 

分 类 号：TG113[金属学及工艺—物理冶金]