Stainless steel surface finishes is a key link in stainless steel processing, which directly affects the corrosion resistance, aesthetics and service life of the material. This article systematically introduces the top ten mainstream stainless steel surface treatment processes to help you choose the best solution according to project requirements.
The importance of stainless steel surface finishes
Stainless steel surface treatment significantly improves its corrosion resistance, easy cleaning and visual effect by changing the microstructure of the material surface. Different surface treatment methods can meet the differentiated needs of food processing, medical equipment, architectural decoration and other fields, and are one of the core factors that determine the performance of stainless steel products.
Detailed explanation of the top ten stainless steel surface treatment processes
No.1 surface treatment (hot rolling pickling)
No.1 surface treatment is the basic treatment method for stainless steel after hot rolling. It removes the oxide scale through high-temperature rolling and pickling to form a rough matte surface. This treatment method has a low cost, but weak corrosion resistance. It is mainly used in chemical equipment, mining machinery and other fields with low surface requirements.
No.2D surface treatment (cold rolling annealing pickling)
No.2D surface treatment adopts cold rolling process, and obtains a flat matte surface after annealing and pickling. It has low magnetic permeability and high flatness, and is suitable for occasions such as LNG storage tanks and semiconductor equipment that require basic corrosion resistance.
No.2B surface treatment (bright annealing)
No.2B surface treatment adds a tension straightening process on the basis of No.2D, and the surface glossiness is increased by 15%, and the corrosion resistance is stronger. It is widely used in food processing equipment, kitchen utensils and other fields that need to take into account both beauty and function.
No.3 surface treatment (intermediate polishing)
No.3 surface treatment is polished with 80-120 mesh abrasive belt to form a uniform texture surface. It has moderate gloss and simple maintenance. It is often used in public facilities such as commercial building interiors and elevator panels.
No.4 surface treatment (standard brushed)
No.4 surface treatment is the preferred solution for the food industry. It forms a fine texture of Ra 0.5-1.5μm through fine polishing. The surface is easy to clean and has strong corrosion resistance. It is widely used in high-frequency cleaning environments such as kitchen equipment and pharmaceutical workshops.
No.6 surface treatment (satin polishing)
No.6 surface treatment uses special sanding belts to achieve soft diffuse reflection effect, with unique visual effect. Although the wear resistance is slightly inferior to No.4, it is still widely used in the decoration field.
No.7 surface treatment (high polishing)
No.7 surface treatment achieves mirror-grade gloss through 320-400 mesh polishing, and the surface defects are controlled to <0.1μm. It is mainly used in high-end markets such as high-end display cabinets and luxury car interiors.
No.8 surface treatment (mirror polishing)
No.8 surface treatment is the pinnacle of stainless steel surface treatment, with a reflectivity of up to 99.8%. The mirror effect is achieved through multi-level diamond polishing, and it is used in high-precision fields such as semiconductor equipment and optical instruments.
BA surface treatment (bright annealing)
BA surface treatment is annealed in a vacuum environment, and the surface presents a mirror gloss and no oxidation marks. The thermal conductivity is increased by 20%, which is particularly suitable for parts such as automotive exhaust pipes and high-temperature heat exchangers that need to take into account both thermal conductivity and durability.
Electrolytic polishing surface treatment
Electrolytic polishing removes tiny surface bumps by electrochemical means to form an ultra-smooth surface with Ra<0.1μm. It complies with FDA and USP certification standards and is widely used in medical devices, high-end kitchenware and other fields that require high cleanliness.
Application scenarios and selection recommendations
Food and medicine field
Preferably choose No.4 or electrolytic polishing surface treatment, and the Ra value must be controlled below 0.8μm to ensure easy cleaning and corrosion resistance.
Architectural decoration field
No.4 surface treatment is the first choice for curtain walls and interiors, and No.8 treatment is suitable for high-end mirror decoration needs.
Industrial equipment field
Chemical storage tanks are recommended to be treated with No.2D/No.2B, and semiconductor equipment requires BA or electrolytic polishing.
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Daxun Alloy Co., Ltd. is a professional stainless steel supplier, supporting customization of various stainless steel surface treatments, if you are interested, please contact us immediately.