Gewalst

Gewalst is the Dutch term meaning "rolled," and in metalworking it refers to metal that has been shaped by passing it through rollers in a rolling mill. The process can be performed hot or cold, resulting in different properties, tolerances, and finishes.

Hot-gewalst products are formed above the metal’s recrystallization temperature, which allows large reductions in thickness and produces a rough surface with oxide scale. Cold-gewalst products are processed below recrystallization temperature, yielding tighter tolerances, a smoother surface, and work-hardening that increases strength. Final products are typically finished by descaling, annealing, or coating to improve ductility, surface quality, and corrosion resistance.

Common gewalst products include sheets, strips, bars, rails, and plates, produced in hot- or cold-rolled forms. The term is used to distinguish rolled forms from other metalworking processes such as extrusion or forging. Rolling can also impart a preferred grain orientation along the rolling direction, which affects mechanical properties and introduces some anisotropy.

Key characteristics of gewalst metal include the dependence of surface finish and dimensional accuracy on the rolling process, the presence or absence of oxide scale on hot-rolled products, and the increased strength and reduced thickness tolerances seen in cold-rolled forms. Finishing steps such as annealing, pickling, or coating are commonly applied to meet specific application requirements.

In industry, gewalst materials are widely used in construction (structural shapes, sheets), automotive components, pipelines, and consumer goods, with standards and specifications (such as EN or ASTM ranges) guiding dimensions and properties for rolled products.