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试验研究了60Si2Mn钢870℃奥氏体化,淬入210～350℃硝盐浴后的显微组织与抗压屈服强度、抗弯强度、挠度、冲击韧性和硬度之间的关系,揭示了钢在马氏体+约20%下贝氏体的混合组织时具有高强韧性,与回火马氏体比较,硬度仅下降HRC 1,强度下降6%,面塑性和韧性均提高一倍以上。冷镦模用这项工艺处理后,使用寿命可提高三倍,经济效果显著。冲击断口的扫描电镜观察表明,马氏体和下贝氏体混合组织和回火马氏体组织断口均属韧窝型,但前者具有较多的撕裂棱,说明60Si2Mn钢具有较好的塑性,这与微观断裂机制密切相关。
The relationship between microstructure and compressive yield strength, flexural strength, deflection, impact toughness and hardness of 60Si2Mn steel after 870 ℃ austenitizing and quenching in 210-350 ℃ was studied. In martensite + about 20% lower bainite mixed tissue with high strength and toughness, compared with the tempered martensite, the hardness decreased only HRC 1, the strength decreased by 6%, plasticity and toughness were more than doubled. Cold heading die with this process, the service life can be increased threefold, the economic effect is remarkable. Scanning electron microscopy observation of the impact fracture shows that the martensite and lower bainite mixed martensite and tempering tissue fracture are dimple, but the former has more tearing edge, indicating that 60Si2Mn steel has good ductility , Which is closely related to the micro-fracture mechanism.