Peruskarkaisun

Peruskarkaisun is a Finnish term that translates to "basic tempering" or "primary hardening." It refers to a heat treatment process used on metals, particularly steel, to increase their hardness and strength. This process is crucial for improving the mechanical properties of materials that will be subjected to wear, stress, or impact.

The peruskarkaisun process involves heating the metal to a specific critical temperature, often above its transformation point, and then rapidly cooling it in a quenching medium such as water, oil, or air. This rapid cooling causes a change in the metal's microstructure, typically forming martensite, which is a very hard and brittle phase.

Following the hardening process, the metal is often subjected to a tempering treatment, which is sometimes referred to as "secondary hardening" or simply tempering. Tempering involves reheating the hardened metal to a lower temperature and holding it there for a period before cooling. This step reduces the brittleness introduced during hardening while retaining a significant portion of the increased hardness and strength. The specific temperatures and times used in both hardening and tempering are critical and depend on the type of metal and the desired final properties. Peruskarkaisun is a fundamental step in creating durable and functional metal components for a wide range of applications.