微量稀土Ce元素对高强海洋平台用钢CCT曲线的影响  

Effect of trace rare earth Ce element on CCT curve of high strength steel for offshore platform

作　　者：母志鹏 董瑞峰[1] 张肖雨 崔青玲[2] 陈基权 吴彦杰 MU Zhipeng;DONG Ruifeng;ZHANG Xiaoyu;CHUI Qingling;CHEN Jiquan;WU Yanjie(School of Materials Science and Engineering,Inner Mongolia University of Technology,Hohhot 010051,China;State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China)

机构地区：[1]内蒙古工业大学材料科学与工程学院,内蒙古呼和浩特010051 [2]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819

出　　处：《轧钢》2024年第4期30-35,共6页Steel Rolling

基　　金：国家自然科学基金项目(52161015)。

摘　　要：为探究微量稀土元素对高强度海洋平台用钢相变行为的影响,利用Formastor-FⅡ全自动相变仪,测定了不同稀土Ce元素含量FH460钢的相变点和过冷奥氏体连续冷却转变(CCT)曲线。对FH460钢在不同冷速条件下的显微组织进行观察,并测量了显微硬度。结合第一性原理计算分析了稀土Ce元素对FH460钢组织转变的影响机理。结果表明:随着稀土Ce元素含量增加,FH460钢的Ac3温度升高、Ac1温度下降,扩大了奥氏体区;与未添加Ce元素FH460钢相比,不同Ce含量FH460钢CCT曲线形状基本不变,但珠光体转变区和贝氏体转变区扩大,且Ce元素抑制了马氏体的转变;当冷速在30~90℃/h时,由于添加稀土Ce元素,FH460钢硬度显著高于未添加Ce元素的FH460钢;微量稀土Ce元素的添加未改变FH460钢在不同冷速下的组织演变规律,但是加入微量稀土元素Ce元素后,珠光体组织得到了细化,且含量也明显增加,同时促进了贝氏体的转变和马氏体板条间距减小。In order to explore the effect of trace rare earth elements on the phase transformation behavior of high strength steel for offshore platform,the phase transformation point and continuous cooling transformation(CCT)curve of undercooled austenite of FH460 steel with different rare earth Ce element content were measured by Formastor-FII automatic phase transformation instrument.The microstructure of FH460 steels under different cooling rates was observed and the microhardness was measured.The influence mechanism of rare earth Ce element on microstructure transformation of FH460 steel was analyzed by first-principles calculation.The results show that with the increase of rare earth Ce element content,the temperature Ac3 ofFH460 steel increases,the temperature Ac1 decreases,and the austenite zone is expanded.Compared with FH460 steel without Ce element,the CCT curve shape of FH460 steels with Ce element is basically unchanged,but the pearlite transformation zone and bainite transformation zone are expanded,and the Ce element inhibits the transformation of martensite.When the cooling rate is 30-90℃/h,the hardness of FH460 steel with rare earth Ce element is significantly higher than that of FH460 steel without Ce element.The addition of trace rare earth Ce element did not change the microstructure evolution of FH460 steel at different cooling rates.However,after adding trace rare earth Ce element,the pearlite was refined and the content was also significantly increased.At the same time,the transformation of bainite and the decrease of martensite lath spacing were promoted.

关 键 词：FH460海洋平台用钢 稀土Ce元素 连续冷却转变 显微组织 

分 类 号：TG142.1[一般工业技术—材料科学与工程]