The procedure for pretreatment of stainless steel pipes is as follows

 (1) Surface mechanical leveling: eliminate the roughness of the stainless steel surface, and achieve a certain surface finish after mechanical polishing and polishing.

 (2) Degreasing: removing oil stains on the surface.

(3) Pickling: remove oxides on the surface. 

(4) Weak corrosion: activate the surface to be treated, remove the surface passivation film, and expose the metal crystal structure