Normalizing
The process of heating the part to the proper temperature, holding it at that temperature until it is uniformly heated, and then cooling it in still air.
Also defined in 1 more source
A process of strain-relieving steel that has been welded and left in a strained condition. The steel is heated to a specified temperature, usually red hot, and allowed to cool in still air to room temperature.
Aviation Maintenance Technician Handbook — Airframe, p. G-24