The high corrosions resistance of this stainless steel relies within the formation of the homogeneous, compact passive layer to the surface area. Annealing colours, scales, slag residues, tramp iron, spatters and this kind of like need to be eliminated, to be able to not demolish the passive layer. Typical specification https://madanijayateknik.com/service/detail/round-bar-plate-sheet-pipe-tube-stainless-steel-321-uns-s32100-din-x6crniti18-10-aisi-321-dan-321h-uns-s32109-din-x8crniti18-10-aisi-321h