40CrMnSiMoVA钢中准贝氏体组织的疲劳强度和疲劳缺口敏感性

THE FATIGUE STRENGTH AND FATIGUE NOTCH SENSITIVITY OF META-BAINITE IN 40CrMnSiMoVA STEEL

本文研究了超高强度40CrMnSiMoVA钢中准贝氏体组织和马氏体组织的疲劳强度。与马氏体组织相比,由贝氏体铁素体和残余奥氏体组成的准贝氏体组织,其光滑及缺口疲劳强度均较高。准贝氏体组织虽具有较低的强度,但因其中较多的残余奥氏体,结果并不损害其疲劳强度。由于该组织具有良好的强度、塑性、韧性配合,使其疲劳缺口敏感性较低。拉伸超载同时提高准贝氏体和马氏体组织的缺口疲劳强度。

The fatigue strength of meta-bainite and martensite in 40CrMnSiMoVA steel is studied. The results shows that the smooth and notch fatigue strength of the meta-bainite consisting of bainite ferrite and retained austenite is higher than that of martensite. The lower 0.2 value and larger retained austenite of meta-bainite do not lower the fatigue strength of the microstructure. Relatively, the fatigue notch sensitivity of the meta-bainite is low due to its good combination of strength, ductility and toughness. The overload tension increases the notch fatigue strength of both microstructures on the steel.