等温温度对超低碳贝氏体钢组织和硬度的影响  

Effect of isothermal temperature on microstructure and hardness of ultra-low carbon bainitic steel

作　　者：孙婷婷[1] 陈伟丽 贾子龙 Sun Tingting;Chen Weili;Jia Zilong(School of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou Inner Mongolia 014010,China;School of Science,Inner Mongolia University of Science and Technology,Baotou Inner Mongolia 014010,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]内蒙古科技大学理学院,内蒙古包头014010

出　　处：《金属热处理》2023年第8期94-98,共5页Heat Treatment of Metals

基　　金：内蒙古自治区高等学校科学研究项目(NJZY21394)。

摘　　要：采用L78型淬火膨胀仪、硬度计、扫描电镜(SEM)和光学显微镜(OM)等分析方法,研究了等温温度对超低碳贝氏体钢组织转变规律及硬度的影响。结果表明,试验超低碳贝氏体钢的TTT曲线包括铁素体转变区、贝氏体转变区、珠光体转变区;在725~650℃等温时,组织为等轴铁素体、少量珠光体和合金碳化物;从625℃开始,组织转变为准多边形铁素体;在600~575℃等温时,铁素体呈块状和少量针状;在575℃以下全为超低碳贝氏体组织。随等温温度降低,试验钢的组织细小,硬度升高,但硬度变化并不明显。在725~700℃等温温度范围内,珠光体含量逐渐降低,在675~600℃等温温度范围内,贝氏体含量呈上升趋势。Effect of isothermal temperature on microstructure transformation and hardness of ultra-low carbon bainitic steel was studied by means of L78 quenching dilatometer,hardness tester,scanning electron microscope(SEM),optical microscope(OM).The results show that TTT curves of the steel includes ferrite transformation zone,bainite transformation zone,pearlite transformation zone.At isothermal temperature of 725-650℃,the microstructure is equiaxed ferrite with a small amount of pearlite and alloy carbides.The microstructure transforms into quasi polygonal ferrite from 625℃.When isothermal treated at 600-575℃,the ferrite appears as block and a small amount of needle-like.Under 575℃,the microstructure is all ultra-low carbon bainite structure.As the isothermal temperature decreases,the microstructure of the tested steel becomes finer and the hardness increases,but the hardness change is not significant.In the isothermal temperature range of 725-700℃,the pearlite content gradually decreases,and in the isothermal temperature range of 675-600℃,the bainite content shows an upward trend.

关 键 词：超低碳贝氏体钢 等温温度 组织转变 硬度 

分 类 号：TG151.2[金属学及工艺—热处理]