【摘要】 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。更多还原

【Abstract】 The impact property,fracture morphology and microstructure of 17-4PH steel after different heat treatments were studied under the range of-60-20 ℃.The results indicate that the impact property of 17-4PH steel decreases gradually with the test temperature decreasing.And the impact value of samples with 816 ℃×0.5 h intermediate treatment among the solid solution and aging is obviously better than that without intermediate treatment under the same test temperature.Fractography of 17-4PH steel is found to be changed from the brittle mixed fracture of quasi-cleavage facets and microvoids without intermediate treating to tough purely microvoids fracture with intermediate treating.Reversed austenite is formed at the prior austenite grain boundaries,martensite lath boundaries and subgrain boundaries during the aging treatment in the samples with intermediate treatment.The uniformly distributed and dispersed reverse transforming austenite has an effect on cutting matrix and toughening structure,the low temperature impact value of the steel increases.更多还原