Abstract: Static uniaxial tension experiment and strain-controlled tension-compression fatigue experiments were conducted at room temperature to cold forging tool material, a matrixtype high speed steel. Mechanical property parameters under static tension and low cycle fatigue loading conditions were acquired through the experiments. Static monotonic tension strain-stress relationship, cyclic strain-stress relationship and cyclic strain-life relationship of the steel at room temperature were derived from regression of the experiment data. The experimental results show that cyclic softening happens to the tool material at all levels of controlled cyclic strain amplitudes in this study. No visible stress saturation is observed before fatigue failure occurrs. A specimen at the controlled strain amplitude of 1.5% was used as an example to investigate the LCF behavior characteristics of this material. The cyclic stress response shows a variation with three stages: the obvious softening stage, the slow softening stage and the final rupture stage.

Key words: cold forging tool material, low cycle fatigue (LCF), high-speed matrix steel, strain-controlled, fatigue property