How can stainless steel 304 and 316 be surface treated to remove at least 3micron layer by pickling method?

Stainless steel 304 and 316 can be surface treated by pickling to remove a 3-micron layer through a chemical solution, typically containing nitric acid and hydrofluoric acid. This acidic solution effectively removes oxide layers, scale, and impurities from the surface. The pickling process involves immersing the stainless steel in the solution for a specified time, followed by thorough rinsing to neutralize the acids. After pickling, passivation can be applied to restore corrosion resistance.