Effect of ECAP on structural, mechanical and functional characteristics of the austenitic Cr-Ni-Ti steels

Abstract

In this study, equal-channel angular pressing (ECAP) of austenitic Cr-Ni-Ti stainless steel was carried out. Effect of ECAP on the evolution of the microstructure and mechanical and service properties of the Cr-Ni-Ti steel was investigated. The microstructure in the completely austenitic state processed by 6 passes of ECAP at 200 °C was obtained and examined by optical and transmission electron microscopy. Mechanical properties were determined by the Vickers micro-hardness measurements and tensile testing. Fracture toughness was evaluated and tribological properties of Cr-Ni-Ti stainless steel processed by ECAP were studied. It was revealed that submicrocrystalline structure with an average size of structural elements of 100 nm produced by ECAP significantly increased the strength properties of Cr-Ni-Ti stainless steel than that in the quenched state. After ECAP the ultimate tensile strength increased by 1.7 times, the fatigue limit by 1,5 times than that in the initial state. It was revealed that Cr-Ni-Ti steel after ECAP demonstrates 2.9 times higher fracture toughness than that in the quenched state. It is established that ECAP does not significantly affect the coefficient of friction and mass wear.