Keményítéseljárás

Keményítéseljárás, a Hungarian term, translates to "hardening process" or "tempering process" in English. It refers to a metallurgical heat treatment applied to ferrous metals, most commonly steel, to increase their hardness and strength. This process is crucial for improving the wear resistance and durability of components.

The keményítéseljárás typically involves two main stages. First, the metal is heated to a specific high temperature, above its critical transformation point. This temperature is dependent on the alloy's composition. At this elevated temperature, the metal's crystal structure changes, allowing for the absorption of carbon atoms into the iron lattice. Following this heating phase, the metal is rapidly cooled, often by quenching in water, oil, or air. This rapid cooling "freezes" the altered crystal structure, creating a hard, brittle phase known as martensite.

However, the resulting martensitic structure is often too brittle for practical use, leading to a tendency to fracture. Therefore, a second stage, often referred to as tempering or "nemesítés," is usually performed. This involves reheating the hardened metal to a lower temperature, below the critical point, and holding it there for a specific duration before cooling. Tempering reduces the brittleness by allowing some carbon atoms to precipitate out and forming more stable phases, while retaining a significant portion of the hardness and strength achieved during hardening. The specific temperatures and times for both hardening and tempering are carefully controlled to achieve the desired balance of hardness, toughness, and ductility for the intended application.