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研究了经两种不同工艺热处理的17-4PH钢在-60～20℃下的冲击性能,并对其冲击断口形貌及显微组织进行分析。结果表明:随着试验温度的降低,17-4PH钢的冲击韧性呈逐渐下降趋势;在相同的冲击试验温度下,在固溶和时效间加入816℃×0.5 h中间调整处理的17-4PH钢的冲击性能明显优于直接时效态试样。断口分析结果显示,直接时效态试样为准解理+韧窝混合型脆性断口,而加入中间处理的试样则为典型的韧性微孔聚集型断口形貌。加入中间处理的试样在随后的时效过程中于原始奥氏体晶界和马氏体板条界-亚晶界处产生了较多的逆转变奥氏体,呈弥散、均匀的分布,具有割裂基体、韧化组织的作用,提高了钢的低温韧性。
The impact properties of 17-4PH steel heat-treated by two different processes at -60 ~ 20 ℃ were studied. The impact fracture morphology and microstructure were analyzed. The results show that the impact toughness of 17-4PH steel decreases gradually with the decrease of the test temperature. In the same impact test temperature, the 17-4PH steel with intermediate adjustment of 816 ℃ × 0.5 h is added between solution and aging The impact performance is obviously better than the direct aging test specimen. Fracture analysis results show that the specimens with direct aging are quasi-cleaved + dimple-brittle fracture, whereas the specimens with intermediate treatment are typical ductile micro-pore-aggregated fracture morphology. In the subsequent aging process, the sample with intermediate treatment produced more retrograded austenite in the original austenite grain boundaries and martensite slab boundary-subgrain boundaries with a dispersed and uniform distribution with Fracture matrix, toughening the role of the organization to improve the low temperature toughness of steel.