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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。
The microstructure and mechanical properties of Si-Mn low alloy steels treated with different phosphorus and sulfur were studied by scanning electron microscope, impact tester and hardness tester. The results show that the normalizing pretreatment can improve the homogeneity of the as-cast sample and make the originally coarse and unevenly distributed as-cast microstructure refine. The normalized pre-treatment + 890 ℃ quenching + 220 ℃ tempering, the organization lath martensite and a small amount of retained austenite and bainite, Rockwell hardness 47.3 HRC, V-notch impact energy absorption of 34.6 J , The best comprehensive mechanical properties. With the increase of the quenching temperature, carbide particles are precipitated in the martensite, the amount of retained austenite decreases, and the hardness increases, but the impact performance decreases obviously.