The surface roughness of sheet decisively influences the shaping behaviour on the automobile industry transfer presses as well as the adhesion and optical properties of the paint. The Pretex(Precision texturing) process has been developed in order to reliably fulfil the increasing current and also future requirements placed on the surface roughness. Salzgitter AG has been using it since early 1997 for the series production of uncoated and surface finished sheets. For this purpose the skin-pass mill work rolls are chromium plated in a closed reactor in order to produce an extremely wear-resistant multi-layer system. This produces irregular distribution of the roughness structure with uniform depths of roughness and small percentages of longer waves,asrequired by the automobile industry.
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