Type 420

Description

Type 420 is a hardenable, straight-chromium stainless steel which combines superior wear resistance of high carbon alloys with the excellent corrosion resistance of chromium stainless steels. Oil quenching these alloys from temperatures between 1800°F to 1950°F (982-1066°C) produces the highest strength and/or wear resistance as well as corrosion resistance. A range of hardness values can be achieved by varying the tempering temperature after quenching.

This alloys is used where strength, hardness, and/or wear resistance must be combined with corrosion resistance.  When sufficient amounts of carbon are added to straight chromium stainless steels, the alloy then has the capability to transform its microstructure through proper heat treatment (hardening) into one that will possess optimum strength, hardness, edge retention, and wear resistance. The presence of sufficient chromium will impart the necessary corrosion resistance and form chromium carbide particles that enhance the wear resistance of the given alloy. The higher the carbon content, the greater the amount of chromium carbide particles, and the greater the strength and hardness for heat treatable straight-chromium stainless steels.  Type 420 can achieve higher hardness than 410 stainless steel due to the higher carbon content.