A Practical Guide to Stainless Steel Grain Finishes: What You Need to Know

Stainless steel finishes result from mechanical polishing, brushing, or rolling processes.

These treatments affect more than appearance—they also influence durability, sanitation, and corrosion resistance.

One key measurement used to define surface smoothness is Roughness Average (Ra), typically measured in microinches (µin) or micrometers (µm). The finer the grain and the higher the grit number, the smoother and more reflective the surface.

Process: Cold-rolled, annealed, and pickled to remove scale, then lightly rolled for uniformity.

• Grit Level: No abrasive finish.
• Ra: 4–8 µin (0.10–0.20 µm).
• Features: Smooth, non-reflective, matte gray.
• View Mirror Metals 2B Mill Finish

Uses: Ideal for deep drawing, forming, and base for further polishing or coating. Common in tanks, chemical equipment, and industrial parts.

Process: Cold-rolled, annealed, and pickled to remove scale, then lightly rolled for uniformity.

• Process: Ground with coarse abrasives.
• Grit Level: 100-120 grit.
• Ra: 12–20 µin (0.30–0.50 µm).
• Features: Coarse, visible grain lines.

Uses: Frequently used in food processing, and where appearance is secondary to function.

• Process: Precision-polished to sanitary specifications.
• Grit Level: 150-180 grit.
• Ra: Typically <15 µin (<0.38 µm).
• Features: Smooth and cleanable; meets 3-A and USDA hygiene standards.

Uses: Dairy, beverage, and food processing equipment. Essential where bacteria resistance and cleanability are critical.

Process: Cold-rolled, annealed, and pickled to remove scale, then lightly rolled for uniformity.

• Process: Ground and polished for a consistent directional grain.
• Grit Level: 120-180 grit.
• Ra: 10–20 µin (0.25–0.50 µm).
• Features: Brushed, professional appearance.

Uses: The most common brushed finish for visible stainless steel applications like handrails, cleanrooms, and kitchen surfaces.

Process: Cold-rolled, annealed, and pickled to remove scale, then lightly rolled for uniformity.

• Process: Finer polishing for softer, smoother grain.
• Grit Level: 240-320 grit.
• Ra: <10 µin (<0.25 µm).
• Features: More uniform, refined, low reflectivity.  A superior #4.
• View Mirror Metals #4 Satin Finish

Uses: Appliances, foodservice, furniture, and architectural surfaces that require both performance and visual appeal.

• Process: Tampico-brushed or soft pad buffed.
• Grit Level: Very fine finishing pad (non-abrasive).
• Ra: <8 µin (<0.20 µm).
• Features: Long grain, dull satin look with soft reflection.
• View Mirror Metals Hairline

Uses: Elevator interiors, architectural facades, decorative applications, and low-glare panels.

We stock and distribute stainless steel in:

• Alloys: 304L (general corrosion resistance), 316L (marine and chemical grade), and 430 (economical ferritic option).
• Gauges: Full range from heavy plate through 26 gauge (0.0187″).
• Standard Widths: 36″, 48″, and 60″.
• Lengths: Standard 96″ to 144″, with longer lengths upon request.
• These treatments affect more than appearance—they also influence durability, sanitation, and corrosion resistance.

Why process more than you need? We help customers reduce waste and streamline fabrication by offering:

• Custom sheets cut to size.
• Coil slitting and cut-to-length for precise dimensions.
• Tight tolerance blanking to minimize downstream trimming.
• Palletized and labeled orders ready for production.

Whether you’re supplying OEM components or fabricating hygienic tanks, working with exact sizes helps cut material handling time, lowers costs, and reduces scrap.

Mirror Metals supports the stainless supply chain with deep inventory, responsive service, and technical knowledge. We serve:

• Regional and national distributors requiring just-in-time supply.
• Contract manufacturers with complex specs and short timelines.
• Fabricators and OEMs who depend on surface integrity and consistency.

We’re here to be your trusted source—not just for stainless steel, but for the knowledge that makes it work for your business.