奥氏体化温度对铁素体耐热钢时效过程中微观组织演化的影响  

Effects of Austenitizing Temperature on the Microstructure Evolution of Modified Ferritic Heat Resistant Steel Upon Aging Treatment

作　　者：高俊华[1] 杜云飞 赵宇 李国栋 周晓胜 GAO Junhua;DU Yunfei;ZHAO Yu;LI Guodong;ZHOU Xiaosheng(School of Innovation and Entrepreneurship,North University of China,Taiyuan 030051,China;Department of Mechanical Engineering,Taiyuan Institute of Technology,Taiyuan 030008,China;CA-Polaris Co.,Ltd.,Tianjin 300480,China)

机构地区：[1]中北大学创新创业学院,山西太原030051 [2]太原工业学院机械工程系,山西太原030008 [3]中农北极星(天津)智能农机装备有限公司,天津300480

出　　处：《中北大学学报（自然科学版）》2023年第6期692-698,共7页Journal of North University of China(Natural Science Edition)

基　　金：中北大学重点实验室研究基金资助项目(202104010910020);山西省研究生创新项目(2023KY576)。

摘　　要：奥氏体化温度对铁素体耐热钢中δ-铁素体的调控具有重要影响。为阐明铁素体耐热钢中δ-铁素体的热稳定性,本文研究了不同奥氏体化温度(1050℃和1200℃)对新型铁素体耐热钢650℃时效过程中微观组织演化的影响,采用光学显微镜、扫描电子显微镜和透射电子显微镜对不同热处理状态下新型铁素体耐热钢的基体组织及第二相颗粒进行了多尺度表征。实验结果表明:随着奥氏体化温度的升高,铁素体耐热钢中δ-铁素体含量增多,δ-铁素体内部有针状MX相形成。在2000 h时效后,金属间化合物Laves相在原奥氏体晶界、马氏体板条界、δ-铁素体晶界或δ-铁素体内部形核,大尺寸M_(23)C_(6)碳化物对Laves相形核具有促进作用,Laves相尺寸随奥氏体化温度的升高而增大。奥氏体化温度对时效过程中M_(23)C_(6)碳化物及MX碳氮化物尺寸变化的影响较小。时效过程中,MX碳氮化物的热稳定性优于M_(23)C_(6)碳化物及Laves相。Austenitizing temperature has significant effects on the regulation ofδ-ferrite in ferritic heat resistant steels.To clarify the thermal stability ofδ-ferrite in ferrite heat-resistant steels,this work has studied the influence of austenitizing temperature(1050℃and 1200℃)on the microstructure evolution of modified ferritic heat resistant steel upon aging treatment at 650℃.By the means of optical microscope,scanning electron microscopy and transmission electron microscopy,the matrix structure and second phases particles of the modified ferritic heat resistant steel under various conditions were examined.The results indicate that the amount ofδ-ferrite increases with the austenitizing temperature increasing,and needle-like MX is formed within theδ-ferrite.Laves phase is distributed along prior austenite grain boundaries,martensitic lath boundaries,δ-ferrite boundaries or withinδ-ferrite interior,at the aging time of 2000 h.Large-sized M_(23)C_(6) has a beneficial effect on the nucleation of Laves phase.The size of Laves phase increases with the increase of austenitizing temperature.Austenitizing temperature has stronger effect on the size of Laves phase than those of M_(23)C_(6) and MX carbonitrides.MX carbonitrides have better thermal stability than Laves phase and M_(23)C_(6).

关 键 词：铁素体耐热钢 LAVES相 Δ-铁素体 碳化物 

分 类 号：TG142.73[一般工业技术—材料科学与工程]