碳锰元素含量对中锰钢相变规律及热轧组织性能的影响  

Effect of carbon and manganese contents on phase transformation and hot rolled microstructure and properties of medium manganese steel

作　　者：董瑞[1] 薛冰 吕科 定巍[1] 李岩[1] DONG Rui;XUE Bing;LÜKe;DING Wei;LI Yan(Materila and Metallurgy School,Inner Mongolia University of Science and Technology,Baotou 014010,China;State Key Laboratory of Baiyunebo Rare Earth Resource Researches and Comprehensive Utilization,Baotou 014030,China;Baotou Research Institute of Rare Earths,Baotou 014030,China)

机构地区：[1]内蒙古科技大学材料与冶金学院,内蒙古包头014010 [2]白云鄂博稀土资源研究与综合利用国家重点实验室,内蒙古包头014030 [3]包头稀土研究院,内蒙古包头014030

出　　处：《轧钢》2023年第3期33-39,共7页Steel Rolling

基　　金：内蒙古自然科学基金项目(2021MS05036)。

摘　　要：中锰钢为新一代先进高强钢,为使其组织获得合适的各相比例,得到理想的力学性能,对C、Mn元素含量的增加所引起的相变规律的变化及对后续加工过程的影响进行了研究。设计了4种化学成分的中锰钢,采用热膨胀仪、SEM、拉伸实验机、XRD测定分析了C、Mn元素含量增加对实验钢相变规律及热轧组织性能的影响。结果表明:C、Mn元素含量的增加能降低实验钢的Ac1和Ac3温度,提高其淬透性,同时使C曲线右移。当Mn质量分数为5%时,1#钢临界冷却速率低于0.5℃/s,其热轧后微观组织由贝氏体、马氏体和少量奥氏体组成,基体上弥散分布着大量的细小碳化物;将C质量分数由0.10%增加至0.15%,2#钢热轧后残余奥氏体体积分数由4.81%增加至9.48%,强塑积由12.2 GPa·%提升至19.0 GPa·%。而当Mn质量分数为7%时,3#钢临界冷却速率低至0.05℃/s以下,其热轧后基体组织为马氏体结构;将C质量分数由0.10%增加至0.15%,4#钢热轧后残余奥氏体体积分数由8.65%降至5.09%,强塑积由15.6 GPa·%降至12.9 GPa·%。因此,当C和Mn的固溶量达到一定程度后,继续提高C含量不利于提升钢的综合力学性能。2#钢可以获得最佳的组织性能。Medium manganese steel is a new generation of advanced high strength steel.In order to obtain appropriate phases proportion and ideal mechanical properties,C and Mn element content changes and their impact on phase transformation and subsequent processing were studied.Four kinds medium manganese steels with different chemical composition were designed.The effect of C and Mn element content on the phase transformation law and hot rolled microstructure and properties of the experimental steels were measured and analyzed by thermal dilatometer,SEM,tensile testing machine and XRD.The results show that the increase of C and Mn content can decrease the temperatures of Ac1and Ac3,improve the hardenability of the experimental steel,and shift the C curve to the right.When the Mn mass content is 5%,the critical cooling rate of 1#steel is less than 0.5℃/s,the microstructure is composed of bainite,martensite and a small amount of austenite,and a large number of fine carbides are dispersed on the matrix.On this condition,increasing the C content from 0.10%to 0.15%can increase the volume fraction of retained austenite and UTS·TE of 2#steel from 4.81%to 9.48%,12.2 GPa·%to 19.0 GPa·%,respectively.While the Mn mass content is 7%,the critical cooling rate of 3#steel is less than 0.05℃/s,the matrix microstructule become to martensitic structure completely.With this Mn content,increasing the C mass content from 0.10%to 0.15%decrease the volume fraction of retained austenite and UTS·TE of 4#steel from 8.65%to 5.09%,15.6 GPa·%to 12.9 GPa·%,respectively.Therefore,when the solid solution of C and Mn reaches a certain level,further increasing the C content will adverse to the comprehensive mechanical properties of the steel.In summary,2#steel can achieve the optimum microstructure and properties.

关 键 词：中锰钢 化学成分 相变规律 热轧 微观组织 力学性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程]