The surface of the stainless steel pipe
will change differently in different environments. Knowing the influence of the use environment on the stainless steel pipe can choose the right model, otherwise the stainless steel pipe will rust and corrode.
Pretreatment is an important treatment step before the surface of stainless steel pipe enters the surface treatment (including pickling, chemical polishing and electrochemical polishing, electroplating, passivation, blackening, coloring, chemical processing, etc.). During the forming process of stainless steel pipes, the surface may be stained with oil, burrs, and rough surfaces and oxides. Therefore, before surface treatment, the oil, burrs, uneven surfaces and oxides must be removed to enable subsequent processing. Get satisfactory results.
The dirt on the surface of the stainless steel pipe to be removed in the pretreatment, it can be divided into two categories: organic and inorganic. Organic pollutants: including mineral oils (such as diesel, motor oil, petroleum jelly, paraffin, etc.) and animal and vegetable oils (such as soybean oil, tea oil, rapeseed oil, lard, tallow, etc.). These oil pollution mainly come from the processing of stainless steel pipes. Used lubricants, cutting oils, quenching oils, polishing and polishing pastes, and fingerprints. Inorganic dirt: Including dirt, dust particles, and oxides generated during heat treatment.
The procedure of stainless steel pipe pretreatment is as follows:
(1) Mechanical leveling of the surface: Eliminate the rough state of the stainless steel surface, and achieve a certain surface finish after mechanical grinding and polishing.
(2) Degreasing: degreasing on the surface,
(3) Pickling: remove the oxide on the surface.
(4) Weak corrosion: Activate the surface to be treated, remove the surface passivation film, and expose the metal crystal structure.
The surface pretreatment method of stainless steel pipe is as follows:
(1) Mechanical method: Use a polisher, polisher or other machinery to remove the rough surface, and then polish and polish it.
(2) Chemical method: degreasing with alkali solution, acid washing with acid solution and organic solvent to dissolve grease and decontamination.
(3) Electrochemical method: the application of electrochemical degreasing and electrochemical etching.
(4) Rolling light, centrifugal light, centrifugal plate light decoration and rotating light decoration, suitable for small parts.
(5) Sand blasting: suitable for large area treatment, and has the functions of decontamination and oxide scale removal.
Therefore, according to the different surface conditions, the quality requirements for the subsequent treatment of stainless steel pipes, using appropriate pretreatment methods.