Understanding Surface States of Stainless Steel for Optimal Performance | MachineMFG

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Understanding Surface States of Stainless Steel for Optimal Performance


Stainless steel has unique strength, high wear resistance, superior corrosion resistance and is not easy to rust.

Stainless steel materials are widely used in various industries: electromechanical, home appliances, 3C digital, manufacturing machinery, decoration, etc. Stainless steel has broad prospects for development.

At the same time, the application and development of stainless steel, to a certain extent, depend on the development of its surface treatment technology.

With the development of the industry and market, the demand for stainless steel surface is diversified and refined.

There are many kinds of stainless steel surfaces, and each has its own representation method.

The development of stainless steel has greatly exceeded other materials in terms of corrosion resistance, appearance, workability, and strength.

Moreover, various surface treatment methods for stainless steel can achieve a wide range of colors and shapes, which have made significant contributions to the advancement of stainless steel.

Surface treatment methods in the manufacturing process of stainless steel and mechanical grinding surface treatment methods.

SurfaceCharacteristicsManufacturing Methods SummaryApplications
NO.1Silvery white, without lusterHot-rolled to a specified thickness, then annealed and descaled to produce a rough, non-glossy surfaceApplications where surface luster is not needed
NO.2DSilvery whiteCold-rolled, then heat-treated and acid-washed, sometimes lightly rolled on a matte roller for a final non-glossy surface treatment2D products used for applications with less stringent surface requirements, general materials, deep drawing materials
NO.2BStronger luster than NO.2DNO.2D treated, then lightly cold-rolled with a polishing roller to achieve appropriate luster. This is the most common surface treatment, which can also be used as the first step of polishing.General materials
BAMirror-like shineThere’s no standard, but typically it’s a bright annealing surface treatment with high reflectivity.Building materials, kitchen utensils
NO.3Rough grindingNO.2D and NO.2B material is ground with a 100-200# grain grinding beltBuilding materials, kitchen utensils
NO.4Intermediate grindingNO.2D and NO.2B material is ground with a 150-180# grain grinding belt to achieve a polished surface. This is universal, a mirror-reflective bright surface with visible ‘grains’.As above
NO.240Fine grindingNO.2D and NO.2B material is ground with a 240# grain grinding beltKitchen utensils
NO.320Ultrafine grindingNO.2D and NO.2B material is ground with a 320# grain grinding beltAs above
NO.400Luster close to BANO.2B material is ground with a 400# polishing wheelGeneral materials, building materials, kitchen utensils
HLHairline grindingA suitable particle size grinding material for hairline grinding (150-240#), which has many grainsBuildings, construction materials
NO.7Approaching mirror grindingThis is ground with a 600# rotary polishing wheelArtistic use, decorative use
NO.8Mirror grindingThe mirror is ground with a polishing wheelReflective mirrors, decorative use

What are the surface conditions of stainless steel?

Common stainless steel surfaces include 2B, BA, NO.1, NO.4, HL, etc.

The following is the stainless steel surface state and its representation method I have arranged.

NO.1 silver white, matte

Hot rolled to the specified thickness, annealed and descaled, a rough, matte surface, suitable for applications that do not require surface gloss.

NO.2D silver white

Heat treatment and pickling are carried out after cold rolling, and sometimes the final light rolling is carried out on the rough roll.

It is a kind of matte surface processing 2D product, which is used for the purpose of not strict surface requirements, general materials, and deep drawing materials.

The luster of 2B is stronger than that of NO.2D.

After the treatment of 2B, the final pass of mild cold rolling is carried out by polishing roller to obtain proper luster.

This is the most commonly used surface processing, which can also be used as the first step of polishing.

BA is as bright as a mirror.

There is no standard, but it is usually bright annealed surface processing with high surface reflectivity.

It is commonly used in building materials, kitchen equipment, etc.

No. 3 rough grinding

Grind No. 1, 2B and other materials with 100-200 # (abrasive belt roughness unit) abrasive abrasive belt. It is often used for decoration, kitchen appliances, etc.

No. 4 intermediate grinding

Use 150-180 # abrasive abrasive belt to grind No. 1, 2B and other materials to obtain polished surfaces.

This is a generic, specular, bright surface with visible grains.

Stainless steel mirror panel is commonly used in mechanical equipment frame elevator car, various tanks, etc.

NO.240 fine grinding

The surface obtained by grinding materials such as NO.1 and 2B with 240 # abrasive belt.

NO.320 very fine grinding

The surface obtained by grinding NO.1, 2B and other materials with 320 # grinding belt.


NO.400 luster is close to that of BA and NO 2B material, general material is grinded with 400 # polishing wheel.

HL Hairline grinding

Abrasive materials with appropriate particle size shall be subject to hair grain grinding (150-240 #).

NO.7 is close to mirror surface grinding, and 600 # rotary polishing wheel is used for grinding. For art and decoration.

8K mirror grinding

Refers to the bright mirror state obtained by repeated grinding with polishing wheel.

For interior and exterior walls of special equipment, decoration, etc.

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