摘要
利用光学金相、透射电镜（TEM）、扫描电镜（SEM）观察,以及拉伸、硬度、冲击等试验方法,研究了热处理对复合微合金化低碳SiMn3型贝氏体高强钢的组织和力学性能的影响,并对其组织与性能关系进行了讨论.结果表明,该钢在空冷条件下,可获得均一的粒状贝氏体组织,并具有良好的强度与韧性（σ0.2=820 MPa、σb=1118 MPa、αKU=87 J/cm^2）;空冷后经200～300 ℃回火,在贝氏体铁素体（BF）基体上析出了弥散细小的ε碳化物,屈服强度、韧性提高（σ0.2=824～835 MPa、σb=1019～1085 MPa、αKU=136～140 J/cm^2）;在400 ℃以上回火,粒状贝氏体组织开始逐渐分解,BF基体上析出椭球状碳化物,并使强度、韧性降低;500～600 ℃回火,产生回火脆性（σ0.2=787～790 MPa、σb=967～1002 MPa、αKU=72～75 J/cm^2）.空冷后低温回火使该钢获得最佳强韧性组合.
Effect of heat treatment process on microstructure and mechanical properties of a multi-microalloyed low-carbon SiMn3 type bainitic steel was investigated by means of the observation of optical microscope, transmission electron microscope （TEM） and scanning electron microscope （SEM）, tensile test, Rockwell hardness test and notch-bar impact test. The relationships between structures and properties of the steel were also discussed. The results show that a homogeneous granular bainite microstructure and a good combination of strength and toughness of the steel are obtained at aircooling condition（σ0.2 = 820 MPa.σb = 1118 MPa.αKU = 87 J/cm^2） ; and the yield strength and toughness of the steel increase somewhat tempered in the temperature range of 200 -300℃ due to the dispersed precipitation of ε carbide particles in bainitic ferrite （BF） laths （σ0.2 = 824 - 835 MPa、σb = 1019 ～ 1085 MPa.αKU = 136 ～ 140 J/cm^2）. After being tempered at temperatures up to 400℃ ,the granular bainite is gradually decomposed and numerous ellipsoid carbide particles precipitate in the bainitic ferrite （BF） laths, as a result the strength and toughness of the steel reduce. Temper brittleness occurs when the steel tempered in the temperature range of 500 -600℃ （σ0.2 = 787 -790 MPa、σb = 967 - 1002 MPa、αKU = 72 - 75 J/cm^2 ）. The best combination of strength and toughness of the tested steel can be obtained after lowtemperature tempering.
作者
仵海东
范培耕
曹鹏军
徐启昆
WU Hai-dong ,FAN Pei-geng ,CAO Peng-jun ,XU Qi-kun （ 1. College of Metallurgical and Materials Engineering, Chongqing University of Science and Technology, Chongqing 400050, China; 2. Institute of Materials Science and Engineering, Chongqing University, Chongqing 400044 ,China）
出处
《金属热处理》
CAS
CSCD
北大核心
Heat Treatment of Metals
关键词
贝氏体钢
热处理
组织
力学性能
bainitic steel
heat treatment
microstructure
mechanical properties
