Karkaistaan

Karkaistaan is the third-person singular present passive form of the Finnish verb karkaistaa, meaning to harden a material by heat treatment. In technical Finnish, karkaistaa refers to processes that increase hardness and wear resistance, most commonly applied to metals such as steel, but also to other materials like glass in the sense of tempering.

The typical hardening process involves heating the material to a specific high temperature to transform its crystal structure, followed by rapid cooling or quenching in oil, water, or air. Depending on the alloy and desired properties, tempering or annealing steps may be used after quenching to adjust toughness and residual stress.

In practice, karkaistaan describes the state of a material that has undergone hardening: for example, steel that is described as karkaistaan has been made harder than its annealed or normalized form. The term can also appear in passive descriptions of finished products, and is frequently used alongside related terms such as karkaisu (hardening), karkaistus (hardening process), and karkaistu lasi (tempered glass).

Notes: The exact steps and terminology can vary by country and industry, and in Finnish technical literature, more precise terms may be used for specific processes or materials. The passive form karkaistaan is commonly used in specifications, product data sheets, and process descriptions to indicate that the material has undergone hardening.