连续退火均热时间对Q&P钢Mn元素分布及加工硬化的影响  

Effect of continual annealing soaking time on Mn element distribution and work hardening of Q&P steel

作　　者：陈连生 张家豪 刘麟 徐海卫 韩赟 杨子旋 李红斌 田亚强 CHEN Lian-sheng;ZHANG Jia-hao;LIU Lin;XU Hai-wei;HAN Yun;YANG Zi-xuan;LI Hong-bin;TIAN Ya-qiang(Key Laboratory of the Ministry of Education for Modern Metallurgy Technology,North China University of Science and Technology,Tangshan 063210,China;Technology Center,Shougang Jingtang Iron and Steel United Co Ltd,Tangshan 063200,China;Key Laboratory of Impact and Safety Engineering,Ministry of Education of China,Ningbo University,Ningbo 315211,China)

机构地区：[1]华北理工大学教育部现代冶金技术重点实验室,河北唐山063210 [2]首钢京唐钢铁联合有限责任公司技术中心,河北唐山063200 [3]宁波大学冲击与安全工程教育部重点实验室,浙江宁波315211

出　　处：《材料热处理学报》2022年第11期111-120,共10页Transactions of Materials and Heat Treatment

基　　金：河北省科技厅重点研发计划项目(20311004D);河北省自然科学基金高端钢铁冶金联合基金项目(E2020209124,E2020209127,E2020209040);河北省自然科学基金重点项目(E2022209049)。

摘　　要：采用扫描电镜(SEM)、X射线衍射(XRD)、电子探针(EPMA)等研究了连续退火均热时间(3、5、8和10 min)对Q&P980钢微观结构演变和力学性能的影响。结果表明:经过均热处理后,Q&P980显微组织主要由铁素体、块/板条状马氏体和少量残留奥氏体组成。随着均热时间的延长,试验钢的板条状马氏体比例升高;残留奥氏体含量先降低再升高,抗拉强度先升高后下降,伸长率与残留奥氏体含量变化趋势一致。均热时间的延长引起加工硬化指数(n)开始迅速升高,5 min后趋于平稳。当均热时间为5 min时,加工硬化指数为0.23,在此条件下,塑性变形过程中残留奥氏体有序、均匀地发生相变诱发塑性(TRIP)效应。均热保温时间初始阶段,Mn元素呈不均匀分布,富集效应明显;随着均热时间的延长,Mn元素分布趋于均匀化;然而,当均热时间为10 min时,Mn元素分布又呈现聚集状态。在试验参数范围内,均热时间为5 min时试验钢的性能最优,抗拉强度为1052.40 MPa,伸长率为22.92%,强塑积为24121.01 MPa·%;合理的均热时间范围为3~6.9 min。Effect of continuous annealing soaking time(3, 5, 8 and 10 min) on microstructure evolution and mechanical properties of Q&P980 steel was studied by means of scanning electron microscopy(SEM), X-ray diffraction(XRD) and electron probe micro-analyzer(EPMA). The results show that after soaking treatment, the microstructure of the Q&P980 steel is mainly composed of ferrite, block/lath martensite and a small amount of retained austenite. With the increase of soaking time, the proportion of lath martensite in the experimental steel increases, the content of retained austenite decreases first and then increases, the tensile strength increases first and then decreases, and the variation trend of elongation is consistent with the content of retained austenite. The extension of soaking time causes the work hardening index(n) to rise rapidly first, and then stabilizes after 5 min. When the soaking time is 5 min, the work hardening index is 0.23. Under this condition, the retained austenite transforms orderly and uniformly during plastic deformation, resulting in phase transformation induced plasticity(TRIP) effect. At the initial stage of soaking time, Mn elements are unevenly distributed and the enrichment effect is obvious. With the increase of soaking time, Mn element distribution tends to be uniform;however, when the soaking time is 10 min, the distribution of Mn elements presents an aggregated state. Within the range of test parameters, when the soaking time is 5 min, the properties of the experimental steel are the best, the tensile strength is 1052.40 MPa, the elongation is 22.92%, and the product of strength and plasticity is 24121.01 MPa·%. The reasonable soaking time range for the experimental steel is 3-6.9 min.

关 键 词：连续退火 Q&P钢 元素分布 显微组织 力学性能 

分 类 号：TG142.3[一般工业技术—材料科学与工程]