Common Surface Treatment Methods Of Stainless Steel

stainless steel has excellent characteristics such as unique strength, high wear resistance, excellent anti-corrosion performance and not easy to rust. Therefore, it is widely used in the chemical industry, food machinery, electromechanical industry, environmental protection industry, household appliances industry and home decoration, finishing industry, giving people a gorgeous and noble feeling. The application and development prospects of stainless steel will become wider and wider, but the application and development of stainless steel is largely determined by the development of its surface treatment technology.

1. Common surface treatment methods of stainless steel 1.1. Introduction to stainless steel varieties

1.1.1. The main components of stainless steel: generally contain high-quality metal elements such as chromium (Cr), nickel (Ni), molybdenum (Mo), and titanium (Ti).

1.1.2. Common stainless steel: chromium stainless steel, containing Cr ≥ 12%; nickel-chromium stainless steel, containing Cr ≥ 18%, containing Ni ≥ 12%.

1.1.3. Classification from the metallographic structure of stainless steel: there are austenitic stainless steels, such as: 1Cr18Ni9Ti, 1Cr18Nil1Nb, Cr18Mn8Ni5. Martensitic stainless steel, such as: Cr17, Cr28, etc. Commonly referred to as non-magnetic stainless steel and magnetic stainless steel.

1.2. Common stainless steel surface treatment methods Commonly used stainless steel surface treatment techniques include the following treatment methods: 1. surface whitening treatment; 2. surface mirror bright treatment; 3. surface coloring treatment.

1.2.1. Surface whitening treatment: During the processing of stainless steel, black oxide skin is produced by rolling, edging, welding or artificial surface fire heating. This hard gray-black oxide scale is mainly composed of two EO4 components, NiCr204 and NiF. In the past, hydrofluoric acid and nitric acid were generally used for strong corrosion removal. However, this method has high cost, pollutes the environment, is harmful to human body, and is highly corrosive, and is gradually eliminated.

At present, there are two main methods of oxide scale treatment: (1) Sand blasting (pellet) method: mainly use the method of spraying micro glass beads to remove the black oxide scale on the surface. (2) Chemical method: Use a non-polluting pickling passivation paste and a non-toxic cleaning solution with inorganic additives at room temperature for dipping. So as to achieve the purpose of whitening the natural color of stainless steel. After processing, it basically looks like a dull color. This method is more suitable for large, complex products.

1.2.2. Mirror gloss treatment method of stainless steel surface: According to the complexity of stainless steel products and different user requirements, mechanical polishing, chemical polishing, electrochemical polishing and other methods can be used to achieve mirror gloss.

1.2.3. Surface coloring treatment: stainless steel coloring not only imparts various colors to stainless steel products, increases the variety of products, but also improves the wear resistance and corrosion resistance of products.