roulage

Roulage, from the French rouler meaning "to roll," is a manufacturing process in which a workpiece is passed between rotating rolls to reduce its thickness, alter its cross-section, or impart a desired surface finish. The term is used in metalworking, polymer processing, and, to a lesser extent, in papermaking and textiles.

In metal rolling, a slab or billet is fed between work rolls and compressed as the rolls rotate. The deformation can occur hot or cold: hot rolling uses high temperature to ease deformation and permit large reductions, while cold rolling achieves tighter tolerances and work hardening, improving strength. Tandem mills or cross-rolling configurations may be used to achieve greater reductions in a single pass.

Equipment includes hot and cold rolling mills, calenders for paper and plastics, and dedicated roll stands with backup rolls. Process control relies on roll gaps, exit thickness, temperature, and lubrication to minimize surface defects and roll wear.

Outcomes include sheets of steel, aluminum, copper, and other metals, as well as polymer films and textiles. Benefits are thickness control, improved surface finish, and altered mechanical properties; drawbacks include roll wear, edge waviness, and springback in some materials.

Roulage has a long history within the broader development of rolling mills, with significant advances during the industrial age that enabled mass production of metal sheets and other rolled products.