Hardening vs. Tempering — What's the Difference?

Involves rapid cooling to transform the steel's structure.

A heat treatment process following hardening.

A heat treatment process to increase steel's hardness.

Involves controlled reheating and cooling.

Results in a martensitic structure.

Enhances the ductility and toughness of steel.

Can make steel brittle if not tempered.

Adjusts the properties of hardened steel.

Used for components requiring high wear resistance.

Crucial for parts subjected to dynamic loads.

The act or process of becoming hard or harder.

To modify by the addition of a moderating element; moderate

Something that hardens, as a substance added to iron to yield steel.

To bring to a desired consistency, texture, hardness, or other physical condition by blending, admixing, or kneading

Gradual exposure of plants to cold weather.

To harden or strengthen (metal or glass) by application of heat or by heating and cooling.

Present participle of harden

To strengthen through experience or hardship; toughen

The process by which something hardens.

(Music) To adjust (the pitch of an instrument) to a temperament.

That which hardens, such as a material used for converting the surface of iron into steel.

To be or become tempered.

Making hard or harder.

A state of mind or emotion; disposition

That which hardens, as a material used for converting the surface of iron into steel.

Calmness of mind or emotions; composure

Abnormal hardening or thickening of tissue

A tendency to become easily angry or irritable

The process of becoming hard or solid by cooling or drying or crystallization;

Anger; rage

The act of making something harder (firmer or tighter or more compact)

A characteristic general quality; tone

The condition of being tempered.

The degree of hardness and elasticity of a metal, chiefly steel, achieved by tempering.

A modifying substance or agent added to something else.

(Archaic) A middle course between extremes; a mean.

Present participle of temper

The act by which something is tempered.

The process of giving the requisite degree of hardness or softness to a substance, as iron and steel; especially, the process of giving to steel the degree of hardness required for various purposes, consisting usually in first plunging the article, when heated to redness, in cold water or other liquid, to give an excess of hardness, and then reheating it gradually until the hardness is reduced or drawn down to the degree required, as indicated by the color produced on a polished portion, or by the burning of oil.

Hardening something by heat treatment

Moderating by making more temperate

While hardened steel has high hardness, it's usually too brittle for most applications and requires tempering to improve toughness.

The tempering temperature is determined by the desired balance of mechanical properties, such as toughness, ductility, and residual hardness.

The cooling rate during hardening affects the steel's microstructure; rapid cooling forms a hard martensitic structure, while slower cooling may result in less hard phases.

Hardening is followed by tempering to reduce the brittleness introduced during hardening, achieving a balance between hardness and toughness.

Improper tempering can lead to inadequate toughness, excessive hardness, or residual stresses, compromising the steel's performance.

Yes, the final hardness can be adjusted by controlling the tempering temperature and duration, with higher temperatures generally leading to lower hardness.

While not all hardened steels are tempered, tempering is often necessary to reduce brittleness and improve the material's practical usability.

Yes, tempering can be repeated to fine-tune the mechanical properties, but this may also depend on the specific steel composition and previous heat treatments.

While hardening and tempering are most commonly associated with steel, some other alloys and metals can also undergo similar heat treatment processes.

The size and thickness can influence heat treatment by affecting heating and cooling rates, which in turn impact the development of microstructures and properties.