EFFECT OF CRYOGENIC TREATMENT AND TEMPERING TEMPERATURE ON MECHANICAL AND MICROSTRUCTURAL PROPERTIES OF AISI 431 STEEL

Abstract

This study investigated the effects of cryogenic treatment and tempering temperature applied after cryogenic treatment on the mechanical and microstructural properties of AISI 431 martensitic stainless steel. After conventional heat treatment (CHT), the steel samples were cryogenically treated at -180 °C for 6 hours and then tempered at 200 °C (CT200) and 300 °C (CT300) for 2 hours. After these processes, hardness measurement, tensile test, and abrasion test were carried out to determine the mechanical properties of the steel samples. In addition, microstructure photographs were taken to determine the microstructural properties. As a result of the study, it was observed that the cryogenic treatment applied after the conventional heat treatment was effective on the mechanical properties of AISI 431 martensitic stainless steel. Cryogenic treatment and tempering temperature showed the greatest effect on wear resistance. CT200 and CT300 samples were 62% and 56% less worn than the CHT sample. Compared to the CHT sample, the yield strength of CT200 and CT300 samples increased by 6.95% and 7.03%, while the hardness increased by 3.89% and 3.52%.This study investigated the effects of cryogenic treatment and tempering temperature applied after cryogenic treatment on the mechanical and microstructural properties of AISI 431 martensitic stainless steel. After conventional heat treatment (CHT), the steel samples were cryogenically treated at -180 °C for 6 hours and then tempered at 200 °C (CT200) and 300 °C (CT300) for 2 hours. After these processes, hardness measurement, tensile test, and abrasion test were carried out to determine the mechanical properties of the steel samples. In addition, microstructure photographs were taken to determine the microstructural properties. As a result of the study, it was observed that the cryogenic treatment applied after the conventional heat treatment was effective on the mechanical properties of AISI 431 martensitic stainless steel. Cryogenic treatment and tempering temperature showed the greatest effect on wear resistance. CT200 and CT300 samples were 62% and 56% less worn than the CHT sample. Compared to the CHT sample, the yield strength of CT200 and CT300 samples increased by 6.95% and 7.03%, while the hardness increased by 3.89% and 3.52%.