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利用金相显微镜OM、扫描电镜SEM、体视显微镜等试验手段,研究了时效时间对一种超高强度不锈钢硬度与冲击性能的影响。结果表明:随时效时间的增加,钢的硬度先上升后下降,其对应的是第二相沉淀强化机制由切过机制转变为Orowan绕过机制。第二相粒子的析出与长大在初期有利于提高钢的强度,后期则会降低钢的强度,且钢的冲击功不断降低,第二相粒子的粗化显著降低了钢的韧性。从节约能源、提高生产效率及综合力学性能的角度出发,最佳时效时间为4 h。
The effects of aging time on the hardness and impact properties of a kind of ultra-high strength stainless steel were studied by metallographic microscope (OM), scanning electron microscope (SEM) and stereomicroscope. The results show that with the increase of aging time, the hardness of the steel first increases and then decreases, which corresponds to the Orowan by-pass mechanism of the second-phase precipitation strengthening mechanism. The precipitation and growth of the second phase particles are beneficial to improve the strength of the steel in the initial stage, and the latter will reduce the strength of the steel, and the impact energy of the steel is continuously reduced. The roughening of the second phase particles significantly reduces the toughness of the steel. From the perspective of saving energy, improving production efficiency and comprehensive mechanical properties, the best aging time is 4 h.