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研究了T-250马氏体时效钢在高温缓冷条件下的冲击性能,对不同缓冷终止温度下试验钢的宏观和微观断口形貌进行观察分析,用扫描电镜观察晶界上的析出物并进行XRD物相分析。结果表明,T-250马氏体时效钢的冲击性能随缓冷终止温度的降低而下降,950℃为热脆敏感温度,此时冲击吸收功迅速下降;试验钢冲击断口的宏观和微观形貌变化规律一致,晶界析出物为Ti(C,N),随缓冷终止温度的降低在晶界上聚集,从而导致试验钢的热脆性。
The impact properties of T-250 maraging steel under slow cooling at high temperature were studied. The macro-and micro-fracture morphology of the test steel under different slow-cooling termination temperatures were observed and analyzed. The precipitates on the grain boundary And XRD phase analysis. The results show that the impact properties of T-250 martensitic steel decreases with the decrease of the slow cooling temperature and the hot brittle temperature is 950 ℃. At this moment, the impact absorption energy decreases rapidly. The macroscopic and microscopic morphology of the impact fracture of the test steel The variation law is consistent with the precipitation of Ti (C, N) in the grain boundary, which aggregates on the grain boundary with the decrease of the slow cooling stop temperature, resulting in the hot brittleness of the test steel.