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本文研究了55SiMnMo钢不同温度的正火组织,取材方向对疲劳裂纹扩展速率的影响。其结果是:在较低的ΔK条件下,55SiMnMo钢的疲劳裂纹扩展速率随正火温度的升高而增大,而在较高的ΔK条件下,则da/dN随正火温度的升高而降低。其原因,作者们认为与疲劳的性质、“块状组织”的数量、贝氏体形态及残余奥氏体的数量有关。文中还再次肯定了正火后再经400℃回火,其疲劳裂纹扩展速率远比正火高的多。不同取材方向对da/dN也有显著的影响。
In this paper, the influence of normalizing microstructure and orientation of 55SiMnMo steel on the fatigue crack growth rate was investigated. As a result, at a lower ΔK, the fatigue crack growth rate of 55SiMnMo steel increases with increasing normalizing temperature, while at higher ΔK, da / dN increases with increasing normalizing temperature Lower. The reason, the authors believe, is related to the nature of fatigue, the number of “massive” structures, the bainite morphology and the amount of retained austenite. The article also re-affirmed the normalized and then tempered at 400 ℃, the fatigue crack growth rate much higher than normalized. Different directions for da / dN also have a significant impact.