Nb微合金化X65MO钢连续冷却转变行为研究  

Study on Continuous Cooling Transformation Behavior of Nb Microalloyed X65MO Steel

作　　者：余宣洵 胡学文[1] 张永青 杨森[1] 孙照阳[1] 吴志文 YU Xuanxun;HU Xuewen;ZHANG Yongqing;YANG Sen;SUN Zhaoyang;WU Zhiwen(Technology Center,Maanshan Iron and Steel Co.,Ltd.,Maanshan 243003,China;Citic WeChat Technology Center,CITIC Metal Co.,Ltd.,Beijing 100020,China)

机构地区：[1]马鞍山钢铁股份有限公司技术中心,安徽马鞍山243003 [2]中信金属股份有限公司中信微合金化技术中心,北京100020

出　　处：《热加工工艺》2020年第14期149-152,156,共5页Hot Working Technology

基　　金：中信铌钢发展奖励基金项目

摘　　要：利用Gleeble-2000D热模拟机研究了Nb微合金化X65MO海底管线钢连续冷却转变行为,采用膨胀测量法并结合金相-硬度法测定了试验钢X65MO的静态和动态连续冷却转变曲线(CCT曲线)。结果表明,试验钢X65MO的静态和动态连续冷却条件下组织均由多边形铁素体加珠光体向针状铁素体转变。静态连续冷却条件下冷却速度达到3℃/s时开始出现针状铁素体组织,而动态连续冷却条件下冷却速度为1℃/s时开始出现针状铁素体组织。当冷却速度达到30℃/s时,动态连续冷却条件下组织主要是针状铁素体,而静态连续冷却条件下组织主要是针状铁素体和多边形铁素体。无论是静态还是动态连续冷却条件下,硬度都随冷却速度的升高而逐渐增大。但动态连续冷却条件下,试样的硬度值比静态的高9~21 HV10。The continuous cooling transformation behavior of Nb microalloyed X65MO submarine pipeline steel was studied by Gleeble-2000 D thermal simulator. The static and dynamic continuous cooling transition curves(CCT curves) of the test steel X65MO were determined by the expansion measurement method and the metallographic-hardness method. The results show that, the microstructure of the test steel X65MO changes from polyhedral ferrite plus pearlite to acicular ferrite under both static and dynamic continuous cooling conditions. When the cooling rate reaches 3 ℃/s under the condition of static continuous cooling, the acicular ferrite structure begins to appear. However, when the cooling rate is 1 ℃/s under the condition of dynamic continuous cooling, needle-like ferrite structure begins to appear. When the cooling rate reaches 30 ℃/s,the needle-like ferrite structure is the main part of the microstructure under the condition of dynamic continuous cooling;under the condition of static continuous cooling, the microstructure is mainly acicular ferrite and polygon ferrite. Under both static and dynamic continuous cooling conditions, the hardness increases gradually with the increase of cooling rate. However,under the condition of dynamic continuous cooling, the hardness of the sample is 9-21 HV10 higher than that of the sample in static state.

关 键 词：NB微合金化 X65MO 连续冷却转变 CCT曲线 显微组织 

分 类 号：TG156.2[金属学及工艺—热处理]