noun
quenching; hardening; tempering
Metalworking term for rapid cooling of heated metal to increase hardness. Often used in the context of steel treatment.
鋼の焼き入れは、硬度を上げるために行われる。
Quenching of steel is performed to increase its hardness.
焼き入れした刃物はよく切れる。
A quenched blade cuts well.
Compound of 焼き (yaki, 'burning' or 'heating', the continuative form of 焼く) and 入れ (ire, 'putting in', the continuative form of 入れる). Literally 'heating and putting in', referring to the process of heating metal and then plunging it into a cooling medium.