低碳贝氏体钢的回火转变及内耗研究  

Studying on Tempering Transformation and Internal Friction for Low Carbon Bainitic Steel

作　　者：蔡茗宇 王传斌 李东岳 CAI Mingyu;WANG Chuanbin;LI Dongyue(Shandong Steel Group Rizhao Co.,Ltd.,Plate Section,Rizhao 276800,China;Shandong Iron and Steel Group Co.,Ltd.,Jinan 250101,China)

机构地区：[1]山东钢铁集团日照有限公司中厚板厂,山东日照276800 [2]山东钢铁集团有限公司,山东济南250101

出　　处：《山东冶金》2020年第2期35-39,共5页Shandong Metallurgy

摘　　要：针对低碳贝氏体钢,采用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射和内耗手段分析了600℃回火过程中的显微组织变化,测试了回火后的屈服强度。结果表明,试验钢轧制态的显微组织是板条贝氏体与粒状贝氏体的混合组织,有少量Mo2C和NbC析出。随着回火时间延长,贝氏体板条的宽度不断增大,板条内部形成较多不同取向的胞状结构,有些板条逐步演化为多边形状,粒状贝氏体不断吞噬板条贝氏体,使显微组织中粒状贝氏体增多且粗化;Mo2C和NbC析出物进一步增多,贝氏体铁素体中的位错密度不断降低;内耗-温度谱中Snoek峰值不断降低,表面处的SKK峰值先降低后升高,心部的SKK峰值先降低后变化不大;屈服强度呈现先提高后降低的趋势。The changes of microstructure in the process of 600℃ tempering transformation were analyzed by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction and internal friction(IF)for low carbon bainite steel.The yield strength of the steel was tested after tempering transformation.The results showed that the microstructures of the test steel in rolled state were composed of lath bainite and granular bainite with a little Mo2C and NbC precipitates.The lath width of bainite was increased continuously with the increase of the tempering time.More cell structures with different orientations was formed in bainite laths.Furthermore,some laths evolved into polygonal shape state.The microstructure of granular bainite was increased and coarsened when it devoured the lath bainite continuously.The dislocation density of the bainitic ferrite was decreased continuously with the increasing of Mo2C and NbC precipitation further.The peak value of Snoek was decreased continuously in internal friction-temperature spectrum.The peak value of SKK at the surface was increased at first and then decreased.The peak value of SKK at the center decreased firstly and then had little change.Besides,the yield strength of the steel was increased firstly and then decreased.

关 键 词：低碳贝氏体钢 回火 碳化物 内耗 屈服强度 

分 类 号：TG142.1[一般工业技术—材料科学与工程]