回火温度对低碳贝氏体钢组织性能的影响.pdfVIP

回火温度对低碳贝氏体钢组织性能的影响1 1 2 2 1 镇 凡 乔 坤 赵庆义 曲锦波 （1.江苏省(沙钢)钢铁研究院，张家港 215625 ；2.沙钢集团钢板总厂， 张家港 215625 ） 摘 要 利用扫描电镜(SEM)、透射电镜(TEM)等实验方法，研究了回火温度对低碳贝氏体钢组织和性能的影响。 结果表明，回火温度对钢的屈服强度的影响明显，而对抗拉强度的影响较小。随着回火温度的升高，屈服强度增加， 增幅达93MPa，冲击韧性大幅提高并在600℃时达到最大值。回火前后力学性能的变化主要与回火后细小粒子的析 出以及大块MA 岛的分解和分解后碳化物的球化有关。随着回火温度的增加，贝氏体铁素体基体位错密度降低，碳 浓度降低，逐渐析出碳化物，并出现了准多边形铁素体组织，MA 岛中的马氏体与残余奥氏体分解，析出碳化物， 碳化物由长条状到粗短条状、再到颗粒状。 关键词 回火温度 MA 岛 粒状贝氏体 析出 Effect of Tempering Temperature on Microstructure and Mechanical Properties of Low Carbon Bainitic Steel Zhen Fan1 Qiao Kun2 Zhao Qingyi2 Qu Jinbo1 (1.Institute of Research of Iron and Steel (IRIS), Sha-steel, Zhangjiagang, 215625; 2. Steel Plate Plant, Sha-steel, Zhangjiagang, 215625) Abstract The effect of tempering temperature on the microstructure and mechanical property of low carbon bainitic steel was investigated by using scanning electron microscopy and transmission electron microscopy. The results show that the effect of tempering temperature on yield strength is much higher than that on tensile strength. The yield strength of the steel tempered at 650 ℃ exhibits an increases of 93MPa compared with that of the as-rolled state. The impact toughness increases with the increase of tempering temperature. Through analysis it is concluded that the major change of mechanical properties after tempering has a connection with dispersive precipitates and decomposition of MA islands and spheroidizing of carbides. As the increase of tempering temperature, the dislocation density and carbon concentration decrease, carbide precipitation and quasi-polygonal ferrite appears. Meanwhile, MA c