On the low-cycle fatigue behavior of a novel high-strength mold steel

• Published in: International journal of fatigue 2023-10, Vol.175, p.107754, Article 107754
• Main Authors: Wegener, T., Krochmal, M., Möller, T.R., Le, M.T., Czap, A., Marianek, F., Fakesch, H., Niendorf, T.
• Format: Article
• Language: English
• Subjects: Cyclic deformation response; Damage parameter; Heat treatment; Low-cycle fatigue; Microstructure; Mold steel; Tool steels
• ISSN: 0142-1123; 1879-3452
• DOI: 10.1016/j.ijfatigue.2023.107754

•Both LTA and HTA leads to a homogeneous, non-textured, fine-grained martensitic microstructure.•Tensile tests reveal a noticeable high strength-ductility product (30,000 MPa-%) for LTA and HTA.•CDRs show a good reproducibility of LCF experiments without pronounced hardening or softening.•The influence of mean stress during LCF was assessed by the Smith-Watson-Topper damage parameter.•Energy-/cost-intensive HTA treatment can be avoided (no pronounced loss of performance) Mold steels, usually being used for dies in low-temperature die casting or in molds for plastic injection, can additionally be considered as material of choice in precision optomechatronics. In any case, these steels will suffer from cyclic loading during their service life. Thus, despite of the envisaged application, the fatigue behavior must be studied comprehensively. In the present study, microstructure and mechanical properties, especially the low-cycle fatigue behavior, of a novel high-strength mold steel were investigated focusing on two different heat treatment conditions, i.e., low- and high-temperature annealing (LTA and HTA). The mechanical behavior being elaborated by tensile tests and strain controlled fatigue tests is discussed based on microstructural insights revealed by electron backscatter diffraction and fracture surface analysis. The results obtained indicate, that a more energy- and cost-intensive HTA treatment can be avoided without pronounced loss of mechanical performance.