hærdes

Hærdes is a Danish verb meaning to harden or to become harder, more rigid, or more durable. In technical contexts it describes processes that increase a material’s hardness or resistance to deformation. The term can apply to metals, glass, polymers and cement-based materials, and is often used in both industrial and scientific language as well as in general descriptions of material treatment.

In metallurgy, hærdning refers to heat-treatment processes that increase the hardness of metals, especially steel. Common steps include heating the metal to a high temperature (austenitizing), followed by rapid cooling (quenching) to form a hard microstructure, such as martensite. The hardness can then be adjusted through tempering, which involves reheating to a lower temperature to improve toughness and reduce brittleness. Different alloys and regimes yield different combinations of hardness and ductility.

In glass, hærdet glas or tempered glass is produced by controlled heating and rapid cooling, creating surface compression that increases strength and safety, since breaking tends to produce small, less hazardous fragments.

In polymers and adhesives, hærdning denotes curing or cross-linking that transforms a liquid resin into a hard, durable solid. Epoxies, silicones and many composite resins rely on curing to achieve their intended mechanical and thermal properties.

In concrete and other cementitious materials, hærdning describes the curing process during which hydration reactions gain strength over time, improving rigidity and load-bearing capacity.

See also: hardening, heat treatment, tempering, curing.