METHOD FOR PRODUCING A FLAT STEEL PRODUCT HAVING HIGH REFLECTIVITY , FLAT STEEL PRODUCT, AND MIRROR ELEMENT FOR SOLAR CONCENTRATORS

The invention relates to a method for producing a flat steel product having high reflectivity , the surfaces of which have an arithmetic mean roughness Ra less than 0.03 µm, wherein flat steel product having an arithmetic mean roughness Ra < 2.5 µm on at least one surface is cold -rolled in several rolling passes, the total deformation rate achieved by means of the cold rolling is 75 - 90%, the deformation rate decreases from rolling pass to rolling pass , the rolling pressure in the first rolling pass is 200 - 800 MPa and the rolling pressure in the last rolling pass is 1000 - 4000 MPa , a rolling oil having a viscosity of 5 - 10 mm/s at 40 °C is added during the cold rolling , the rolling speed is > 200 m/min, and the cold rolling is performed by means of a working roller having a mean roughness Ra < 0.01 µm at least in the last rolling pass. Then the cold- rolled flat steel product is annealed under a protective gas atmosphere and rerolled dry. The invention further relates to a flat steel product produced accordingly and a solar concentrator produced from such a flat steel product.