Effects of Prestrain and Baking on the Tensile and Fatigue Properties of Fe–0.1C–5Mn Transformation‐Induced Plasticity Steel

This study aims to investigate the effects of uniaxial tensile prestrain (PS) and bake hardening (BH) on tensile and force‐controlled (R = 0.1) high‐cycle fatigue (HCF) properties of Fe–0.1C–5Mn medium Mn transformation‐induced plasticity (TRIP) steel. Stress‐life data of the as‐received (AR: 0% prestrain) and 10%, 15%, and 20% prestrained (PS10, PS15, PS20) samples have been generated under both baked and unbaked conditions. It is manifested that prestraining increases the HCF life of the steel. The addition of BH further increases the HCF life. The fatigue limit is greatly improved from 433 MPa (AR) to 532 MPa (BH20), and the maximum incremental value is as great as 99 MPa. It is attributed to the austenite to martensite transformation (progressive TRIP effect) that occurs during the prestraining and cyclic loading processes. Prestrain and baking both increase the fatigue resistance of Fe–0.1C–5Mn TRIP steel, due to the progressive TRIP effect. Fatigue limit σ0.1 increases from 433 MPa (AR: as received) to 532 MPa (BH20), reaches a maximum incremental of 99 MPa.