Physical Modeling of the Steel Sheet Topography in Skin Pass Rolling and Its Influence on Susceptibility of Sheets to Deep Drawing Marek Burdek  This work is focused on the formation of sheet surface topography and its influence on drawability of sheets. 3D roughness measurements is used to study surface topography and cupping tests by Erichsen and by Swift – to establish and to compare drawability of steel sheets with and without surface treatment. In addition, statistical analysis is presented to determine parameters characterizing the surface topography which has a decisive influence on the susceptibility to sheet-metal forming. The research shows that a change in surface topography in steel sheets with high plasticity (grades DC03, DC04, and DC05) does not significantly affect their drawability measured in Erichsen test, but it can significantly affect the susceptibility of sheets to deep drawing. In case of stainless steel X6Cr17, a clear impact of surface topography on the technological properties is ascertained – both the Erichsen’s value and the limit drawing ratio depend strongly on the type of abrasive used for vapor blasting. 1. Introduction One of the aims of skin passing is to ensure suitable surface topography of steel sheets that should facilitate further processing of sheets and should provide the best surface quality of formed parts. [1–8] This task is carried out with the use of skin pass mill with work rolls of properly prepared surface topography. The main purpose of using skin passing in case of carbon steel sheets is to eliminate yield stress in order to avoid formation of surface defects in the form of Hartmann–Luders’ lines during deep drawing. During skin passing, the surface topography of steel sheets is formed as well. [9–12] It influences appearance and surface roughness of sheets. Elimination of yield stress occurs owing to deformation (1–2% elongation) and the surface topography of steel sheets is a reflection of work roll’s topography. In order to obtain regular and repeatable surface topography, it is necessary to use modern methods of work roll surface treatment like laser texturing), electric discharge texturing, electron beam texturing, or their varieties. [13–17] Due to the fact that studies using industrial skin-pass mill are quite expensive – as they entail stoppages of industrial production, it was decided to carry out physical modeling of changes in sheet topography using abrasive blasting. It was assumed that using non-metallic abrasives, it is possible to form surface topography of steel sheets in a manner similar to the skin passing. The kinetic energy of abrasive particles striking the surface of the metal causes strengthening of the subsurface layer of steel sheets similarly to skin passing and it does not change mechanical properties of steel sheets. The aim of physical modeling was to create on sheet surface the topography of diverse roughness with the application of vapor blasting instead of skin passing and to examine technological properties of such sheets as com- pared to skin passed steel sheets without surface treatment. Statistical analysis was carried out to determine parameters characterizing the surface topography which had a decisive influence on the susceptibility to sheet-metal forming. 2. Experimental Section 2.1. Preparation of Experimental Material Surface treatment of steel sheets was carried out in a sandblasting machine using as abrasives: quartz sand, aloxite, and glass balls. Each of these had different physical properties, different form and granulation, thus ensuring formation of different surface topography. [  ] M. Burdek Department of Manufacturing Technology and Application of Products, Institute for Ferrous Metallurgy, Miarki 12-14 44-100 Gliwice, Poland Email: mburdek@imz.pl DOI: 10.1002/srin.201500090 www.steel-research.de 456 steel research int. 87 (2016) No. 4 ß 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim FULL PAPER