Describes a steel alloy with sufficient hardenability that it does not require a liquid quench to achieve full hardness. When heated above its critical temperature, it will form a hard martensitic structure even when cooled slowly in ambient air. This property minimizes distortion and the risk of cracking, making it ideal for complex tool and die shapes.
Since this is a self-hardening tool steel, we can just pull the fixture from the furnace and let it sit on the cooling rack.
Do not mix it up with
- Air hardening: Self-hardening is an older term for air-hardening steels, though both describe the same metallurgical behavior.
Related terms
Air hardening
Describes steels with enough alloy to harden fully when cooled in still air or gas instead of a liquid.
Hardenability
A steel's ability to form martensite to a given depth, set by its chemistry and grain size, not its hardness.
Distortion
Unwanted change in shape or size of a part during heat treatment, such as bowing, warping or ovality.