annealoinnin

Annealoinnin, in English annealing, is a heat treatment used to alter the microstructure of materials in order to improve ductility, reduce hardness, relieve internal stresses, and refine grain structure. The process typically involves heating a material to a prescribed temperature, holding it at that temperature for a period, and then cooling it in a controlled manner. The exact temperatures, times, and cooling rates depend on the material and the desired properties.

In metals, annealing methods include full annealing, stress-relief annealing, recrystallization annealing, and normalizing. Full annealing heats the metal to a high temperature, maintains it to allow diffusion and grain reformation, and then cools slowly to produce a soft, ductile microstructure. Stress-relief annealing operates at lower temperatures to reduce residual stresses without significant grain growth. Recrystallization annealing is used after plastic deformation to restore a new, strain-free grain structure. Normalizing involves heating to a high temperature and air cooling to achieve a finer grain structure than furnace cooling.

Polymers and glasses can also undergo annealing. In semi-crystalline polymers, annealing near the crystallization or melting temperature increases crystallinity and relieves stresses, affecting dimensional stability and mechanical properties. In glass, annealing removes internal stresses by controlled cooling through the glass transition region, reducing the risk of spontaneous cracking and improving stability.

Applications span metal forming, electronics, optics, wire drawing, and glass manufacturing. Key factors include peak temperature, hold time, heating and cooling rates, and the atmosphere. Proper annealing balances softness and strength, minimizes defects, and incurs energy and time costs.