低碳微合金管线钢过冷奥氏体连续冷却转变  

Continuous cooling transformation of undercooling austenite for low-carbon microalloyed pipeline steel

作　　者：李红英[1] 林武[1] 宾杰[1] 魏冬冬[1] 曾翠婷[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2010年第3期923-929,共7页Journal of Central South University:Science and Technology

基　　金：湖南省自然科学基金资助项目(05JJ30200)

摘　　要：利用膨胀法和差热分析法结合金相-硬度法,在Gleeble-1500热模拟机上测定一种低碳微合金管线钢以不同速度连续冷却时的膨胀曲线,结合DSC曲线和金相组织分析,确定该钢的临界温度及相变温度,获得该钢的连续冷却转变曲线(CCT图),研究该钢连续冷却时的奥氏体转变。研究结果表明:添加0.21%Mo起到抑制铁素体和珠光体作用,促进针状铁素体组织的形成,实验钢在5.0～20.0℃/s的较宽冷却速度范围内连续冷却都能得到需要的针状铁素体组织,表明低碳Mn-Nb-Mo微合金管线钢容易得到管线钢工程所需要的组织。The different dilatometric curves of continuous cooling transformation were measured on Gleeble-1500 thermal mechanical simulator with methods of dilatometric change and differential thermal analysis. Referencing microscopic test and hardness measurement,the critical points and phase transformation points were determined,and the continuous cooling transformation curves （CCT diagram） of a low-carbon microalloyed pipeline steel were obtained. Transformation of austenite in the course of continuous cooling was investigated. The results show that adding 0.21% Mo can inhibit the formation of ferrite and pearlite,and promote the formation of acicular ferrite. Acicular ferrite can be obtained within a wider cooling rate range of 5.0-20.0 ℃ /s,which shows that the microstructure needed for engineering application can be obtained in the low-carbon Mn-Nb-Mo microalloyed pipeline steel.

关 键 词：低碳微合金管线钢 连续冷却 相变 连续冷却转变曲线(CCT图) 

分 类 号：TG151.2[金属学及工艺—热处理] TG151.3[金属学及工艺—金属学]