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    温度和试样形状对新能源汽车用无取向电工钢疲劳行为的影响

    Effect of temperature and sample shape on fatigue behavior of non-oriented electrical steel for new energy vehicles

    • 摘要: 以B20AV1200无取向电工钢为研究对象,基于大量疲劳试验数据,分析了该钢在25~200 ℃时,试样形状与温度对其疲劳应力-寿命曲线及疲劳极限强度的影响规律。结果表明:在相同加载条件下,采用哑铃状试样测得的疲劳极限强度较漏斗状试样高出40~55 MPa;随着温度的升高,该电工钢的疲劳强度呈上升趋势,但增幅逐渐减小,这是因为在温度与应力的共同作用下,电工钢中多余的碳、氮原子会以细小弥散的质点形式析出,同时疲劳过程中的棘轮变形量也随之增大,二者共同作用使材料的屈服强度增大,进而对疲劳裂纹的起裂起到抑制作用。

       

      Abstract: Taking B20AV1200 non-oriented electrical steel as the research object, based on a large number of fatigue test data, the influence of sample shape and temperature on the fatigue stress-life curve and fatigue limit strength of the steel at 25-200 ℃ was analyzed. The results show that under the same loading conditions, the fatigue limit strength measured by dumbbell-shaped specimen was 40-55 MPa higher than that of funnel-shaped specimen. With the increase of temperature, the fatigue strength of the electrical steel showed an upward trend, but the increase gradually decreased. This was because under the combined action of temperature and stress, the excess carbon and nitrogen atoms in the electrical steel would precipitate in the form of fine dispersed particles, and the ratcheting deformation in the fatigue process also increased. The combined effect of the two increased the yield strength of the material, which in turn inhibited the initiation of fatigue cracks.

       

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