Stainless Steel Finishes: 2B, BA, No.4, 8K

Two coils with the same grade can look and perform differently because of the surface line on the purchase order. A finish name is a useful starting point, but polished appearance varies with the mill surface, abrasive route, equipment, sample and viewing conditions.

Mill finishes

No.1 (hot rolled, annealed, pickled). A dull, comparatively rough surface associated with hot-rolled flat product. It is commonly used where function matters more than a decorative appearance. Confirm the finish designation and acceptance criteria in the governing product standard.

2B (cold rolled, annealed, pickled, skin passed). A smooth, lightly reflective mill finish widely specified for cold-rolled sheet and coil. It can be a base for further finishing or a final functional surface, subject to the cleanability, appearance and fabrication requirements of the application.

BA (bright annealed). A bright mill surface produced through a controlled annealing route. It can be more reflective than 2B, but it is not the same surface as a mechanically polished mirror. Handling marks and flatness remain part of acceptance.

Mechanically applied finishes

No.4 (brushed / satin). A directional mechanically finished surface. Commercial No.4 appearance varies with mill route, abrasive sequence, base finish and viewing conditions. Use an approved sample, grain direction and a measured roughness or gloss requirement where appearance is critical.

Hairline (HL). A long directional grain used on architectural and equipment panels. “Hairline” alone is not a complete inspection criterion; define the sample, grain direction, finished side and protection film.

No.8 / 8K (mirror). A highly reflective mechanically polished surface. Reflectivity, haze and image distortion depend on base material, polishing route and flatness. Agree a sample and handling plan before decorative work.

Common starting points by use

Application	Common finish starting point	Confirm before ordering
Structural or process plate	No.1	Pickling condition, surface defects and downstream cleaning
General cold-rolled fabrication	2B	Finished side, flatness and post-fabrication treatment
Appliance or trim panel	BA	Reflectivity, handling marks and protective film
Kitchen or architectural panel	No.4 or hairline	Sample, grain direction, roughness and panel matching
Highly reflective decoration	8K / mirror	Flatness, haze, sample, film and fabrication handling

Finish feasibility also depends on grade and product form. Review ferritic grades such as 430 and 439, or duplex grades such as 2205, against the required sample and available processing route rather than assuming identical appearance.

Ordering details that prevent disputes

• State base and final finish. Do not rely on a commercial nickname alone.
• Define the inspected side and grain direction. This matters when panels are cut, bent, book-matched or installed together.
• Use a sample or measured criterion. Record sample approval, viewing light, roughness or gloss target and acceptable variation when appearance is critical.
• Coordinate surface protection. Identify film type, adhesive suitability, removal conditions, interleaving and packing without assuming one film suits every fabrication route.
• Review fabrication effects. Bending, welding, heat tint, grinding and cleaning can change the delivered surface.
• Include corrosion-service details. Roughness, contamination, drainage and cleaning all matter. Pair the finish review with the 304 vs 316 comparison and project requirements.

Use the finish library to prepare the surface line, then send the grade, dimensions, sample and acceptance criteria for an order-specific processing review.