Etch Structure Classification

Etch Structure Classification, otherwise known as an oxalic acid etch test or sodium hydroxide etch test, is performed as a screening test on stainless steel prior to a corrosion resistance test. Etch Structure Classification is a fast way of determining if a stainless steel piece is free of susceptibility to intergranular attack. If this is the case, these parts will, in turn, have low corrosion rates and can be deemed acceptable.