Fe-C-Mn-Si-Al双相钢两相区加热过程中的奥氏体相变行为研究  

Study on Austenite Transformation Behewior of Fe-C-Mn-Si-Al Dual-phase Steel during Intercritical Annealing

作　　者：谢钊远 林关强 王定峰 蓝慧芳[1] XIE Zhaoyuan;LIN Guanqiang;WANG Dingfeng;LAN Huifang(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China)

机构地区：[1]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：《热加工工艺》2024年第17期127-130,共4页Hot Working Technology

基　　金：国家自然科学基金面上项目(51774082)。

摘　　要：采用Dictra软件模拟与实验验证相结合,研究了不同加热条件下铁素体+渗碳体向奥氏体的相变过程,重点分析了渗碳体溶解规律及其对奥氏体相变动力学的影响规律,借助场发射电子探针对不同加热路径下的铁素体及马氏体组织形貌及元素分布进行观测,使用透射电镜对渗碳体和残余奥氏体进行了表征。结果表明,慢速加热至740℃长时间等温与加热至780℃较短时间等温对比发现,虽然渗碳体刚溶解完全时的奥氏体分数相差不大,但在渗碳体溶解的过程中,奥氏体相变的方式不尽相同。在慢速加热条件下,铁素体晶界处为奥氏体优先形核地点;快速加热条件下,由于形核驱动力提高,铁素体晶粒内部的渗碳体处同样可以形核。740℃等温结合快速加热,获得了马氏体与残余奥氏体的“壳-核”组织结构。The austenite transformation from ferrite+cementite was investigated by modelling with Dictra software and experimental validation.Especially,the dissolution of cementite as well as austenite transformation kinetics was analyzed.Using field emission electron probe,the morphology of ferrite and martensite and its elements distribution under different heating routes were detected.And the cementite and retained austenite were characterized using transmission electron microscope(TEM).The results show that,compared with the slow heating to 740℃for long isothermal periods and heating to 780℃for a short isothermal time,although the austenite fraction is not very different when the cementite starts to dissolve,but in the process of carbursome dissolution,the austenitic phase transition is different.Under slow heating,austenite preferentially nucleates on ferrite grain boundary.While,under fast heating,austenite can also nucleate on cementite/ferrite boundaries inside ferrite.Combining isothermal treatment at 740℃with fast heating,a special shell-core structure composed of martensite and retained austenite is obtained.

关 键 词：Fe-C-Mn-Si-Al钢 渗碳体溶解 奥氏体相变 残余奥氏体 

分 类 号：TG151.1[金属学及工艺—热处理] TG142.1[金属学及工艺—金属学]