Polymer coated steels are used in the packaging industry to produce a variety of products, for example cans. During the production of the cans, the steel substrate and the polymer undergo a roughness development. The roughness development is important regarding the product performance and depends (among others) on the original grain size of the steel substrate. The goal of this paper is to investigate the influence of the grain size of the steel substrate on the surface roughness during the production process of the can. For this purpose, 3D topography measurements were performed after several process steps (drawing, redrawing and ironing) of can making. A larger grain size results in a higher roughness increase and a lower minimum coating thickness of the inside of the can.