Finite Element Simulation on Fatigue Properties of S500MC HighStrength Steel Automobile Rim by Hydroforming

With 2.0 mm thick S500MC microalloyed high strength steel plate as raw material, an automobile rim was manufactured by hydroforming process. The fatigue properties of the rim were analyzed by finite element method, and were compared with those of conventional rolling formed SPFH540 medium strength low alloy steel rim with uniform wall thickness of 2.3 mm and S500MC microalloyed high strength steel rim with uniform wall thickness of 2.0 mm. The results show that the maximum reduction rate of wall thickness of hydroformed rim was 10.9%. The change trend of section bending stress and radial stress of the hydroformed rim was consistent with those of the two rolling formed rims, indicating that the local thinning of the rim did not significantly change the stress of the rim. The maximum bending stress and radial stress of the hydroformed rim were lower than the yield strength of the steel, the maximum bending strain and radial strain were far less than the yield strain, and the fatigue property safety factor was greater than 1, indicating that the local thinning of wall thickness would not affect the bending and radial fatigue properties of the rim.