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本文研究了蠕变断裂韧性对三种低合金Cr-Mo-V钢在蠕变一疲劳交互作用下裂纹开裂和扩展的影响.试验表明,材料韧性对裂纹开裂和扩展起重要作用,脆性状态时,裂纹开裂时间比蠕变时短,二者间的裂纹扩展速度无明显差别;韧性状态时,裂纹开裂时间不仅比蠕变时短,而且其裂纹扩展速度比蠕变时大得多.此外,低合金Cr-Mo-V钢经蠕变一疲劳交互作用后有脆化倾向,其脆性程度取决于钢的原始韧性值.韧性状态时,蠕变-疲劳交互作用显著促使三种Cr-Mo-V钢由韧性向脆性转变;而在脆性状态时,这种脆性转变不明显。
In this paper, the effect of creep rupture toughness on crack initiation and propagation of three kinds of low alloy Cr-Mo-V steel under creep-fatigue interaction was studied. The results show that the material toughness plays an important role in crack initiation and propagation, , The crack initiation time is shorter than that of the creep, and there is no significant difference in the crack growth rate between the two. In the ductile state, the crack initiation time is not only shorter than the creep, but also the crack growth rate is much larger than the creep. In addition, Cr-Mo-V steel has brittleness tendency after creep-fatigue interaction, and its brittleness depends on the original toughness value of steel.In creep-fatigue interaction, the three Cr-Mo- V steel transition from ductile to brittle; in the brittle state, the brittle transition is not obvious.