Mechanical properties of martensitic stainless steel (AISI4 20) subjected to conventional and cryogenic treatments

Martensitic Stainless Steel (AISI420) MSS are vastly used because of their properties conventional which mix good mechanical and corrosion resistance. Cryogenic up to -196°C for different soaking time and heat treatments at (1000, 500, 200°C) for 15 minutes is one of the ways that used to enhance mechanical properties of these steels by meanstransformation of retained austenite, deformation regarding martensite then carbide refinement. the result showed an increase in tensile strength of samples that were treated cryogenically and tempered at 500°C was 933 (MPa) compared to samples that just treated conventionally in austenitizing and tempering at the same temperature that was 880 (MPa). The hardness values increased considerably to 414HV and 321 HV for the specimen that tempered at 200°C and 500°C respectively, precipitation of small carbideswas observed that this is responsible for the improvement in the mechanical properties of the MSS are vastly used because of their properties conventional which mix good mechanical and corrosion resistance. Cryogenic up to -196°C for different soaking time and heat treatments at (1000, 500, 200°C) for 15 minutes is one of the ways that used to enhance mechanical properties of these steels by meanstransformation of retained austenite, deformation regarding martensite then carbide refinement. the result showed an increase in tensile strength of samples that were treated cryogenically and tempered at 500°C was 933 (MPa) compared to samples that just treated conventionally in austenitizing and tempering at the same temperature that was 880 (MPa). The hardness values increased considerably to 414HV and 321 HV for the specimen that tempered at 200°C and 500°C respectively, precipitation of small carbideswas observed that this is responsible for the improvement in the mechanical properties of the material.