The surface processing of stainless steel is done through different processing methods so that the surface of stainless steel has different glosses, colors, patterns, etc., which greatly improves the appearance of stainless steel and makes it achieve aesthetic effects. In addition, surface processing also has important functional effects, such as a smooth stainless steel surface not only looks clean but is also easy to clean and keep clean; in a corrosive environment, the smoother the surface, the better the corrosion resistance; the pattern is increased by cold pressing Strength, in the re-manufacturing and middle of stainless steel products (such as deep drawing),
it is hoped that the texture of the metal surface will be slightly rough to catch the grease. A proper amount of grease can reduce tool wear and reduce tool indentation; wire surface Processing and coating are for the convenience of deep processing (such as cold heading of solid parts); the specified surface also has economic factors, and the cold-rolled bright annealed surface does not need to use the more expensive No. 8 polished surface.
Types of Stainless Steel Processing
Stainless steel surface processing is usually divided into two categories: one is the surface obtained by the stainless steel manufacturer with different production processes, usually called rolled surface processing; the other is the surface specially performed on the rolled material in order to change the surface level or nature Processing is generally referred to as deep processing of stainless steel surface.
Rolled Surface Processing
The stainless steel plates and strips produced by rolling mills generally undergo processes such as hot rolling, cold rolling, annealing, pickling, and finishing. Because the surface of cold-rolled stainless steel strips occupies a special position in use, the surface processing of cold-rolled stainless steel strips can be divided into different surface processing types (or grades) according to different process methods, especially cold-rolled stainless steel strips. Rolled steel plates and steel strips have a variety of surface processing types, and national standards have corresponding regulations. For example, the 2B, No. 1, and BA surfaces often say fall into this category.
Deep Processing of Stainless Steel Surface
For some special purposes, the properties of the stainless steel surface must be changed, and the stainless steel surface may be deeply processed through different processes.
(1) Electroplating and evaporation surface The surface of stainless steel is coated with a layer of wear-resistant, scratch-resistant, and corrosion-resistant coating by electroplating to improve the surface properties of stainless steel. In order to make the covering layer and the metal substrate firmly bond, different methods can be used to pretreat the surface to remove the oil and rust on the surface. The advantage of electroplating is that it has almost no effect on the microstructure of the base material, the common chrome plating, and nickel plating. Mainly used as artwork and decoration.
(2) Electrolytic polishing Surface electrolytic polishing is the opposite of electroplating. Instead of depositing chromium or nickel on the substrate, it uses stainless steel as the anode and electrolyzes with a specially formulated electrolyte to etch away a thin layer of 2-40PM on the surface of the stainless steel. A smooth, clean and bright body with excellent corrosion resistance is obtained.
(3) Colored surface Coloring is to immerse stainless steel in hot chromic acid or sulfuric acid solution, and then perform cathodic hardening treatment in another acid solution. The base metal reacts with hot acid to form a basically colorless transparent film, but it shows a color under the interference of light. After polishing and coloring, the metal has a high gloss. These colored stainless steels not only have enhanced corrosion resistance, and do not fade, but can also be bent or lightly stretched.
(4) Surface coating Reprocessing (pre-coating) after the coating is mainly used for roof-building materials. Coating after processing (post-coating) is mainly used for building exterior building materials. The stainless steel surface is coated with fluorocarbon resin and silicone polyester color-retaining coating to increase the corrosion resistance in the marine environment, making the roof durable, pollution-resistant, and anti-glare.