低碳含铌微合金钢的连续冷却相变行为及显微组织  

Continuous Cooling Transformation Behavior and Microstructure of Low Carbon Nb-Bearing Microalloyed Steel

作　　者：宗云[1] 赵莉萍[2] 麻永林[2] 王宝峰[2] 宋海彬[3] 

机构地区：[1]山东轻工业学院机械工程学院,济南250353 [2]内蒙古科技大学材料科学与工程学院,包头014010 [3]济南钢铁集团总公司第一小型轧钢厂,济南250101

出　　处：《机械工程材料》2011年第7期31-34,38,共5页Materials For Mechanical Engineering

基　　金：内蒙古高校科学研究项目(NJ04025)

摘　　要：利用Gleeble-1500D型热/力模拟试验机,采用热膨胀法测定了不同铌含量低碳含铌微合金钢在不同冷速下的相变点,研究了奥氏体连续冷却时的相变行为及铌含量和冷却速率对该钢相变组织与硬度的影响。结果表明:随着铌含量和冷速的提高,γ→α相变温度降低,相变组织变得复杂,显微硬度升高;铌含量较低(小于0.024%,质量分数)的钢在冷速较低(3℃·s^(-1))时,显微组织为较粗大的铁素体和少量珠光体,冷速提高后主要是由尖角形、多边形铁素体和贝氏体组成的混合组织;铌含量较高(0.06%)的钢在高冷速(50℃·s^(-1))下出现了针状铁素体组织。The transformation temperatures at different cooling rates of low-carbon Nb-bearing microalloyed steels with different Nb contents were obtained by thermal dilation method using Gleeble-1500D thermo-mechanical simulator. The transformation behavior of austenite during continuous cooling and the effects of Nb content and cooling rate on transformation microstructure and hardness were studied. The results show that the γ→α transformation temperature lowered, the microstructure became more complex and the microhardness increased with the increase of Nb content and cooling rate. The microstructure of the steel with low Nb content （〈0. 024wt%） was composed of coarser ferrite and minor pearlite at slow cooling rate of 3℃ · s^-1 , the sharp-angle shaped and polygon shaped ferrite as well as banite were got at higher cooling rates. The acicular ferrite was got at higher cooling rate （50 ℃ · s^-1） in the higher Nh content （0.06wt%）steel.

关 键 词：显微组织 低碳含铌微合金钢 冷却速率 铌含量 

分 类 号：TG111.5[金属学及工艺—物理冶金] TG156.1[金属学及工艺—金属学]