karkaistusprosessin

Karkaistusprosessi, known in English as hardening or quenching, is a heat treatment process used to increase the hardness and strength of metals, particularly steels. The process involves heating the metal to a specific temperature above its critical point, where its crystal structure transforms. This is followed by rapid cooling, typically in a quenching medium such as water, oil, or brine. The rapid cooling prevents the formation of softer, more ductile microstructures, instead promoting the formation of martensite, a very hard and brittle phase.

The specific temperature and holding time during heating are crucial and depend on the type of steel and its desired properties. The choice of quenching medium also significantly impacts the cooling rate and the resulting microstructure. While hardening makes the metal stronger and more resistant to wear, it also increases its brittleness. Therefore, hardening is often followed by a tempering process, which reduces brittleness while retaining a significant portion of the achieved hardness. Karkaistusprosessi is a fundamental technique in metallurgy, widely applied in manufacturing to produce tools, machine parts, and other components requiring high strength and durability.