Stainless Steel Finishes: 2B, BA, No.4, Hairline and Mirror

Two stainless sheets can share the same grade and size and still look completely different. The surface finish affects appearance, cleaning, corrosion performance and cost, yet many inquiries simply say "polished".

This guide explains the common stainless steel finishes and how to specify the right one.

Stainless Steel Finishes Compared

Finish	How it is made	Appearance	Typical uses
No.1	Hot rolled, annealed and pickled	Dull, rough	Plate for tanks and industrial equipment
2B	Cold rolled, annealed, pickled and lightly skin passed	Smooth, slightly reflective	General fabrication and process equipment
BA	Cold rolled and bright annealed	Bright and reflective	Trim, appliances and decorative parts
No.4	Polished with abrasives	Short directional grain	Kitchens, food equipment and panels
Hairline (HL)	Long continuous abrasive lines	Long directional lines	Elevators, architecture and furniture
Mirror (No.8 / 8K)	Polished with fine abrasives, then buffed	Highly reflective	Decorative panels and signage

Mill Finishes: No.1, 2B and BA

These are produced at the mill as part of rolling and annealing. 2B is the most common general-purpose sheet and coil finish. No.1 is a hot-rolled plate finish, so it is not the same as a smooth sheet surface. BA is brighter than 2B, but it is not the same as a polished mirror finish.

Polished Finishes: No.4, Hairline and Mirror

These are applied mechanically after the mill stage. No.4 and hairline both have a visible direction, but hairline lines run longer and look more continuous. Mirror finish reflects like glass, and it also shows fingerprints, scratches and water marks more easily.

How to Choose the Right Finish

• Hidden or further processed parts: 2B or No.1 usually makes more sense, because there is little value in paying for an appearance no one will see.
• Parts that are touched often: a brushed finish such as No.4 or hairline hides marks better than mirror.
• Decorative work: compare a physical sample under the real lighting, as photos can be misleading.
• Corrosive sites: a clean, smooth surface helps corrosion resistance, but it does not replace the correct grade. See our 304 vs 316 stainless steel guide.
• Food and hygiene use: follow the surface roughness limit in your own sector's standard, not a finish name alone.

Four Mistakes to Avoid

• Using only the word "polished": this could mean No.4, hairline or mirror.
• Assuming the name fixes the roughness: published roughness figures vary widely. If Ra matters, state the limit and how it will be measured.
• Ignoring grain direction: on brushed panels, the direction of the grain affects cutting and how panels match on site. Agree it on your drawing.
• Forgetting protective film: finished surfaces can be scratched in handling, so specify film and packing where appearance matters.

What to Include in Your Inquiry

Stainless steel sheet, ASTM A240 304, 1.5 × 1219 × 2438 mm, No.4 finish, one side PVC film, grain along the 2438 mm length, 10 tons, CIF [destination port].

• Grade, standard and size
• Finish name, and a sample or Ra limit if the appearance or roughness is critical
• Which side or sides need the finish, and whether film is needed
• Grain direction for brushed products
• Packing and handling requirements

Frequently Asked Questions

What is the difference between 2B and BA?

Both are mill finishes. BA is bright annealed in a controlled atmosphere and is more reflective than 2B.

Is No.4 the same as hairline?

No. Both are directional, but hairline has longer, more continuous lines. Compare samples, because suppliers may interpret these terms differently.

Is mirror finish more corrosion resistant?

A smoother surface can help, but grade, environment and cleaning still matter. Do not rely on finish alone in chloride service.

Order the Right Finish

Shanghai Banzhijia Steel supplies stainless sheet and plate and stainless coil and strip in several finishes. Tell us the grade, size and application, and our sales team will confirm the available finish and processing options.