Selection Guide for Stainless Steel Surface Treatments
No. 1 Finish
Hot-rolled, annealed, and pickled surface with a uniform dull gray appearance.
Ra:3.2–6.3 µm
Form:Plate, sheet (heavy gauge)
2D Finish
Cold-rolled, annealed, and pickled with no final rolling pass. Produces a dull, matte, non-reflective surface with good formability.
Ra:0.4–1.0 µm
Form:Sheet, strip
2B Finish (Most common)
Produced by cold rolling, annealing, and pickling, followed by a final light skin-pass rolling using polished rolls. The surface is smooth and bright, exhibiting diffuse reflection.
Ra: 0.1–0.5 µm
Forms: Sheets, strips, coils, tubes/pipes
BA Finish
Annealed in a protective atmosphere (hydrogen/nitrogen), so no oxide scale forms and no pickling is needed. The result is a highly reflective, mirror-like surface straight from the mill.
Ra:0.05–0.2 µm
Form:Sheet, strip, pipe
No. 8 Finish (Mirror)
The highest-grade mirror finish, produced by polishing with progressively finer abrasives (1000+ grit) followed by buffing.
Ra:≤ 0.05 µm
Form:Sheet, plate
HL Finish
Continuous, fine, unidirectional brush lines giving a silky satin texture. Excellent at hiding fingerprints and scratches - the most popular finish for public-use architectural surfaces.
Ra:0.2–0.8 µm
Form:Sheet, strip, coil
If you would like to further clarify your requirements, please let us know:
Is your goal to improve appearance, prevent corrosion, or perform cleaning and restoration?
What is the item, or what is the stainless steel grade?
FAQ
What is the most common stainless steel surface finish?
The 2B finish (cold rolled, annealed, pickled, and lightly rolled) is the most commonly specified stainless steel surface finish worldwide. It accounts for the majority of all stainless steel sheet production and is used across food processing, medical, architectural, chemical, and general manufacturing applications. Its ASTM A480 designation is No. 2B, EN equivalent is 2B, JIS is No. 2B, and GB is 2B.
What is the difference between 2B and BA stainless steel finish?
The key difference is the production process. A 2B finish is cold rolled, annealed, and pickled, then given a final light rolling pass using polished rolls, producing a smooth, bright but diffusely reflective surface. A BA (Bright Annealed) finish is annealed in a protective atmosphere (hydrogen/nitrogen) so no oxide scale forms and no pickling is required, producing a highly reflective, mirror-like surface. BA (EN 2R) has a lower Ra value (0.05–0.2 µm) than 2B (0.1–0.5 µm) and looks noticeably more like a mirror.
What is a No. 4 finish stainless steel?
A No. 4 finish is a standard polished stainless steel surface produced by grinding with 120–180 grit abrasive belts, followed by a finer polishing pass. It has a smooth, uniform, semi-reflective appearance with visible but fine grain lines. It is one of the most popular finishes for architectural, food processing, and medical equipment applications. Its EN equivalent is 2J, JIS designation is No. 4, and GB designation is No. 4, with a typical Ra value of 0.2–0.6 µm.
What is the difference between 2D and 2B stainless steel finish?
A 2D finish is cold rolled, annealed, and pickled with no final rolling pass, resulting in a dull, matte, non-reflective surface with a typical Ra of 0.4–1.0 µm. A 2B finish undergoes an additional final light rolling pass using polished rolls after pickling, producing a smoother, brighter, more reflective surface with a typical Ra of 0.1–0.5 µm. 2D is preferred when the material will undergo further processing (deep drawing, forming) or when a uniform matte appearance is required; 2B is preferred for most finished products.
What is a hairline (HL) finish on stainless steel?
A hairline (HL) finish is a brushed stainless steel surface with continuous, fine, unidirectional polishing lines, typically produced with 120–180 grit abrasive belts followed by finer polishing in one direction. It has a silky, satin-like appearance that hides fingerprints and minor scratches well. HL is widely used for elevator panels, escalator cladding, kitchen appliances, and architectural interiors. It has no standard ASTM number (HL is an industry designation), the JIS designation is HL, and the GB designation is HL.
What is a No. 8 mirror finish stainless steel used for?
A No. 8 finish is the highest grade mirror finish achievable on stainless steel, with a highly reflective, mirror-like surface and a typical Ra of 0.05 µm or less. It is produced by polishing with progressively finer abrasives (typically up to 1000+ grit) followed by buffing. No. 8 finishes are used for decorative and prestige applications: architectural feature panels, sculpture, high-end elevator interiors, luxury product housings, display fixtures, and art installations where maximum reflectivity is required.
How do I specify the surface finish of stainless steel?
To specify a stainless steel surface finish, first reference the applicable standard (ASTM A480, EN 10088-2, JIS G4305, or GB/T 3280), then state the finish designation (e.g., "2B finish per ASTM A480"). For polished finishes, additionally specify the surface roughness Ra value in micrometers (e.g., "No. 4 finish, Ra ≤ 0.6 µm") if required for your application. For critical or aesthetic applications, request a sample or a finished-surface test piece from your supplier, since actual appearance can vary with the base material, polishing practice, and lighting conditions.
Which stainless steel surface finish is best for food processing equipment?
For food processing equipment, a 2B finish is suitable for general contact surfaces, but a No. 4 finish (or finer) is typically recommended for product-contact surfaces because its smoother surface (Ra 0.2–0.6 µm) reduces bacterial adhesion and is easier to clean and sanitize. For the most hygienic applications, electropolished surfaces (Ra 0.2–0.4 µm or finer) are preferred, as electropolishing removes surface peaks and produces a chemically clean, micro-smooth surface that is the easiest to keep hygienic.