回火温度对EA4T车轴钢显微组织及力学性能的影响

采用不同的回火温度(500、550、600和650 ℃)对EA4T车轴用钢进行调质热处理,使用OM、SEM、拉伸试验及冲击试验等测试分析了材料的显微组织和力学性能,研究了回火温度对EA4T钢显微组织及力学性能的影响。结果表明,随着回火温度的升高,回火组织转变为回火索氏体,EA4T钢强度有所降低,韧性及塑性提高。当回火温度升高至600 ℃以上时,EA4T钢的冲击断口形貌呈韧窝状。回火处理后,EA4T钢抗拉强度与硬度的经验公式为:R_m=2.9477V+45.59。

Effect of tempering temperature on microstructure and mechanical properties of EA4T axle steel

EA4T axle steel was quenched and tempered at different tempering temperatures (500, 550, 600, and 650 ℃). The microstructure and mechanical properties of the material were tested and analyzed by means of OM, SEM, tensile test and impact test to study the effect of tempering temperature on microstructure and mechanical properties of the EA4T steel. The results show that as the tempering temperature increases, the sorbite structure is formed, which induces the decrease of strength and the increase of toughness and plasticity. The impact fracture morphology of the EA4T steel is dimpled when tempered at above 600 ℃. The empirical formula of tensile strength and hardness of the EA4T steel after tempering treatment is as follow: R_m =2.9477V+45.59.