Rust free stainless steel is only obtained if the steel surface is always handled carefully and properly. The high chrome-nickel steel alloy is corrosion resistant, for example, when the ability to form a so-called “passive layer” remains. This layer, consisting of chromium oxides, can only occur if the surface is pure metallic.
Especially when welding, for example dark scaled layers and discoloration appear. This destroys the “passive layer”, creating potential targets for corrosion. Even deformation processes result in ferritic particles being deposited on the working surface.
The subsequent mechanical surface treatment cannot restore the rust protection. The widespread processing methods such as grinding, turning or blasting lead to tensions in the near-surface regions, which results in long-term susceptibility of stress and corrosion cracking.
Pickling the stainless steel surface removes these impurities permanently from the surface. The metal builds up a new passive layer, which protects it from corrosion. In order that our individual handling solutions always meet the highest quality standards we work closely with our subsidiary APV Surface Technology.