底盘控制臂用800 MPa级高强度钢的疲劳特性研究

Research on Fatigue Behavior of 800 MPa Grade High Strength Steel Used for Chassis Control Arm

底盘零部件的疲劳失效是影响车辆使用寿命的重要因素之一,研究钢材的疲劳性能可以为车身的轻量化设计提供有力数据支撑。比较了两种底盘控制臂用高强度贝氏体钢CP800和FB800的低周疲劳及高周疲劳性能。通过Coffin-Manson-Basquin公式计算低周疲劳寿命预测曲线,利用升降法绘制高周疲劳S-N曲线并计算得出CP800和FB800钢的平均疲劳极限分别为278和270 MPa。比较几种车身常用600~800 MPa级高强钢的低周疲劳E-N曲线,发现CP800钢在相同应变幅下的10^(5)~10^(6)周次寿命区间具有更优异的低周疲劳性能。

Fatigue failure of chassis parts is one of the important factors affecting the service life of vehicles.The research on the fatigue property of steel can provide strong data support for the lightweight design of vehicle.The low cycle fatigue and high cycle fatigue performance of the two kinds of bainite high strength steels CP800 and FB800 for chassis control arm were compared.The prediction curve of low-cycle fatigue-life was calculated by Coffin-Manson-Basquin formula,and the high-cycle fatigue stress-life curve was fitted by up-and-down method,the average fatigue limit of CP800 and FB800 steels were 278 and 270 MPa,respectively.By comparing the low-cycle fatigue strain-life curves of several commonly used 600 to 800 MPa high strength steels for vehicle,it was found that CP800 steel had better low-cycle fatigue performance in the life range of 10^(5) to 10^(6) cycles under the same strain amplitude.