To provide different wave forms to a steel filament of a steel structure.

The steel structure is adapted for the reinforcement of elastomers, and the steel reinforcement includes one or more steel elements 10. At least one of the steel elements 10 is provided with first and second crimps. The first crimp lies in a plane that is substantially different from the plane of the second crimp. Formation of the both crimps can be carried out efficiently by using two pairs of toothed wheels 12, 14 which are not externally driven. The crimps render it possible to obtain steel structures with an increased penetration of rubber or with an increased elongation at break.