Gegloeide

Gegloeide is a Dutch term describing metal that has undergone gloeien, or annealing, a heat-treatment process aimed at altering its mechanical properties. The main purpose is to relieve internal stresses, soften the material, and increase ductility, improving formability and machinability. The term is most commonly applied to steel but can also refer to other metals such as copper and aluminum.

The basic procedure involves heating the material to a prescribed temperature above its recrystallization point, holding it for a defined period, and then cooling at a controlled rate. Variants include full annealing, which produces a soft, ductile structure with homogenized grains; and process annealing, which relieves residual stresses after cold working with minimal loss of strength. Normalizing is related but typically involves higher heating and air cooling to refine the grain and enhance toughness; some sources distinguish normalizing from gegloeide material depending on context.

After gegloeide treatment, hardness generally decreases while ductility and toughness increase. Surface oxide scales can form when heating occurs in air, so protective atmospheres or descaling may be used to maintain surface quality.

Applications of gegloeide metals include components that require good formability, machinability, or post-forming workability, such as sheets, springs, and structural parts. The term emphasizes the post-treatment state of the metal rather than a specific alloy or composition.

Etymology: gegloeid is the past participle of gloeien, meaning to glow or to heat to a glow in order to alter the material’s microstructure. Related terms include annealing, heat treatment, and stress relief.