【摘要】 利用扫描电镜、冲击试验机、硬度计研究了不同工艺处理低硫磷Si-Mn系低合金钢的显微组织和力学性能。结果表明:正火预处理可以改善铸态试样组织均匀性,使原本粗大且分布不均的铸态组织得到均匀细化。经正火预处理+890℃淬火+220℃回火时,组织为板条马氏体和少量残留奥氏体及贝氏体,洛氏硬度为47.3 HRC,V型缺口冲击吸收能量为34.6 J,综合力学性能最好。随着淬火温度的升高,马氏体间有碳化物颗粒析出,残留奥氏体量减少,硬度升高,但冲击性能下降明显。更多还原

【Abstract】 Microstructure and mechanical properties of low sulfur and phosphorus Si-Mn series low alloyed steel were studied by means of SEM,impact testing machine and hardness tester. The results show that normalizing treatment can improve the uniformity of as-cast microstructure,and refine the original coarse and uneven cast structure. After normalizing pretreated and then quenched at 890 ℃ plus tempered at 220 ℃,the microstructure of the steel consists of lath martensite,a small amount of retained austenite and bainite,its hardness and the impact absorbed energy reaches 47. 3 HRC and 34. 6 J,respectively,which is the best in comprehensive mechanical properties.With the increase of quenching temperature,carbide particles separate out between the marten sites,while residual austenite volume decreases,along with the increasing hardness and the decreasing impact toughness.更多还原