YUHONG GROUP - Surface treatment of stainless steel flange

1. Surface blackening: Stainless steel flanges are blackened and oxidised in the process of fabrication, either by rolling, trimming, welding, or by fire and heat treatment of the surface of the surface of the workman's house. This hard black oxide was previously removed by strong corrosion using hydrofluoric acid and nitric acid. However, this method is costly, polluting to the environment, harmful to the human body, and highly corrosive, and is gradually being phased out. Currently, the main methods of treating oxidised plutonium are the sand blasting method and the chemical method.
(1) Sand blasting (shot blasting) method: The main method is to remove the blackish oxidised surface by spraying micro glass beads.
(2) Chemical method: A non-polluting pickling passivation paste and a room temperature, non-toxic cleaning solution with organic additives are used for immersion washing. The purpose of whitewashing the intrinsic colour of the stainless steel flange is achieved. This method is preferred for large, complex products.

2. surface mirror brightening treatment method: Depending on the complexity of the stainless steel flange product and the requirements of the user, mechanical polishing, chemical polishing, electrochemical polishing, and other methods can be used to achieve a mirror-like surface luster.

3. Surface Colouring Treatment: Colouring stainless steel flanges not only gives stainless steel flange products a variety of colours and adds variety to the product's colour palette, but also improves the product's abrasion and corrosion resistance.

There are five ways to apply a tint to stainless steel flanges:
(1) Chemical oxidation coating method; that is, a film of colour is formed by chemical oxidation in a specific solution.
(2) Electrochemical oxidation method; the colour of the film formed by electrochemical oxidation in a specific solution.
(3) Ion deposition oxide coating method; the film colour is formed by electrochemical oxidation in a specific solution.
(4) High-temperature oxide implantation; this is the process of immersing the workpiece in a specific molten salt and holding it at a certain process parameter, so that the workpiece will form an oxide film of a certain thickness, which will take on a variety of different hues.
(5) Pyrolytic Colour Separation: more complex and less commonly used in the industry.