It is a process carried out to improve the surface roughness, light reflection, and consequently the appearance of the material, as well as to enhance material flatness and stabilize its mechanical properties. At the end of the process, the surface obtained is a 2B surface.

Cold-rolled, annealed, and surface-treated stainless steel coils are of 2D surface quality. The surface tempering process, also known by names like Skin-Pass, is performed with very low roughness and large-diameter rollers. The aim here is the reflection of a homogeneous, low-roughness surface on the roller surface.

One of the reasons for the large roller diameters in the Skin-Pass process is to avoid plastic deformation of the material during this operation. This process, especially for precision materials rolled to very tight tolerances with cold rolling and annealed, aims to crush and shine the surface in the elastic deformation zone without causing permanent shape changes (e.g., rolling, etc.).

The reason this process is also called tempering is because the pressure and tension applied in the elastic zone help to relatively alleviate residual stresses and crystallographic irregularities in the material’s internal structure.

Therefore, especially in the case of ferritic stainless steels where Lüders bands are observed, repeating the Skin-Pass process can eliminate them, resulting in a more isotropic material. In practice, an increase in elongation values is observed in rolls that have undergone the Skin-Pass process. Ultimately, the surface, which has reduced roughness and increased brightness, is referred to as 2B (Bright)