Surface Finishes: 2B, No.4, Mirror – Explained

Introduction to Stainless Steel Surface Finishes

Stainless steel plates come in various surface finishes that impact not only their aesthetic appeal but also their functional suitability for different industries. Among the most commonly demanded finishes in India and worldwide are 2B, No.4, and Mirror (No.8) — each offering distinct benefits for hygiene, reflectivity, formability, or corrosion resistance. Hindustan Steel Corporation supplies all three variants in SS 304, SS 316, and premium alloys like SS 904L.

What is 2B Finish, No.4 Finish, and Mirror Finish?

• 2B Finish: A cold-rolled finish with a smooth, dull matte surface. Ideal for industrial, chemical, and food processing applications.
• No.4 Finish: Brushed finish with fine polishing grit lines. Common in kitchen equipment, architecture, and pharmaceutical machines.
• Mirror (No.8) Finish: Highly reflective and glossy surface achieved by buffing. Used in high-end architecture, elevators, and luxury interiors.

Applications by Finish Type

• 2B Finish: Pressure vessels, tanks, chemical process equipment
• No.4 Finish: Food processing, pharma cleanrooms, kitchen appliances
• Mirror Finish: Decorative panels, signage, escalators, cosmetic-grade enclosures

Mechanical Properties & Impact of Finishes

While surface finish doesn’t alter core mechanical properties, finer finishes like Mirror can slightly reduce formability due to excessive polishing. All finishes can be applied to plates with tensile strength between 500–750 MPa depending on grade.

Chemical Composition Relevance

Surface finish selection often depends on the grade:

• SS 304 and SS 316 are most commonly supplied in 2B and No.4
• Mirror polish is preferred in corrosion-resistant SS 316L or SS 904L for decorative plus durable performance

Available Standards for Polished Stainless Steel Plates

We supply plates as per:

• ASTM A240 / ASME SA240
• EN 10088 (Europe)
• JIS G4305 (Japan)
  All surface finishes comply with industry-accepted Ra values (roughness average):
• 2B: ~0.3µm
• No.4: ~0.4–0.6µm
• Mirror: <0.1µm

Thickness & Size Availability by Finish

• 2B: 0.5 mm to 50 mm
• No.4: 0.8 mm to 20 mm
• Mirror: 0.8 mm to 6 mm
  Standard widths: 1000mm / 1250mm / 1500mm
  Length: 2500mm / 3000mm or custom cut-to-size

Buffing, Grinding & Surface Treatment Tips

• Use alumina or silicon carbide belts for No.4 finish
• Final buffing with rouge compounds for Mirror finish
• Clean 2B plates with mild alkaline cleaners to avoid oxidation

Fabrication & Cleaning Guidelines

• 2B: Best for welding and bending
• No.4: Directional grain — avoid deep scratches during cutting
• Mirror: Handle with protective film and gloves to prevent fingerprinting

Why Buy Polished Plates from Hindustan Steel Corporation?

We offer finish consistency, scratch-free delivery, and export-grade polishing processes. All finishes come with traceability, packaging, and surface test certification. Our in-house grinding units allow large batch processing with precise Ra control.

Export Grade Surface Finished Plates

We export No.4 and Mirror Finish stainless plates to:

• UAE, Qatar, Saudi Arabia
• Vietnam, Malaysia
• South Africa, Kenya
  With fumigation-free, PVC film laminated, waterproof-wrapped bundles.

How to Select the Right Finish for Your Project

• For chemical/industrial use → Go for 2B
• For food/pharma interiors → Choose No.4
• For decorative/luxury applications → Opt for Mirror
  Ask us for Ra values, finish samples, or technical sheet comparison.

Certifications & Compliance

Our polished SS plates meet:

• ISO 9001:2015
• ASTM/EN finish tolerances
• IBR (for applicable grades)
  Each plate is accompanied by:
• Surface roughness report
• Mill TC / Third-party inspection on request

FAQs for Surface Finishes: 2B, No.4, Mirror – Explained