Effects of Modifying a Hot Stamping Process of 22MnB5 Thick Sheets in Terms of Fatigue Strength

Hot-stamped ultra-high-strength steels, as established in automotive body-in-white, have already been considered for add-on parts of commercial vehicle chassis frames such as rear and front underride guards. Replacing thinner hot-formed steels for the fine-grained structural steels with plate thicknesses of up to 9 mm usually used in this area offers enormous potential for weight-savings. In order to fully exploit these advantages, the substitution must be extended to other components, such as load-bearing structures. For this purpose, the material has to meet high fatigue strength requirements. Therefore, a modified hot forming process is presented which allows the adjustment of the advantageous fatigue properties of the manganese-boron steel 22MnB5. In this paper, different heat treatments are investigated to produce favorable reference manufacturing parameters in terms of fatigue strength. The material samples produced by different heat treatments are tested for their fatigue strength. In addition, the influence of sandblasting on the fatigue strength is investigated.