It groups all manufacturers of flat and long products, both unalloyed and alloy steel, including stainless steels.  The producers of non-welded tubes, welded tubes, cold-rolled strip, cast steel, cold-formed profiles, calibrated steel, road barriers, coated profile sheet and free forging are also members.

UNESID was created in 1968 and throughout its life it has collaborated in the structuring of Spanish and European industry.  It is a founding member of CEOE and CONFEMETAL and is a member of, inter alia, the Worldsteel Association and EUROFER.

The Union of Iron and Steel Companies has witnessed the intense transformation process which has given rise to more competitive, technologically advanced and environment friendly companies, perfectly adapted to the world markets that nowadays shape the steel sector.