All steel plate and sheet is hot-rolled as a first rolling step, after which it is annealed in order to attain homogeneous material characteristics. Annealing produces an oxide on the steel, which is removed by shot blasting and by pickling in an acid bath.
As a result of these manufacturing operations, stainless steel acquires a relatively coarse, matt grey surface denoted 1D, with an Ra value in the order of 2-8 µm; depending on steel grade and some process parameters. Localised grinding marks may appear on plate material, but have no practical implications for the use of the steel.
Hot rolled plate of this finish is mostly used for heavy process equipment and in thickness from around 5 mm and upward.