Flat Washers

Flat washers are flat, circular or square shaped standard fasteners with intermediate holes for bolts or screws to distribute axial loads on fasteners, protect joint surfaces and enhance joint stability. Flat washers are suitable for use with Metric Thread, UNC/UNF threads and custom threaded fasteners.

Flat washers prevent stress concentrations, reduce friction and surface damage, and increase resistance to loosening by increasing the area under stress. It is widely used in assembly and connection systems in machinery, construction, automotive, electric power and home appliance industries, and is a basic functional part in the field of industrial fastening.

Specifications

Metric sizesM2 to M160
Internal diameter1/4” to 2″
Outside diameter5/16” to 3”
Strengthgrade 4.8 to 8.8; A2-70, A4-80.
MaterialCarbon steel, aluminum, copper, nylon, etc.
StandardISO, DIN, UNI, ASME, EN, IFI, NF.
PackagingPlastic box, color box, carton, pallet, or customized packaging.

Surface Treatment Process

We work with more than 10 surface treatment manufacturers and can provide any surface treatment service.

  • Natural color
  • Galvanized
  • Oxidized blackening
  • Nickel plating
  • Dacromet
  • Electroplated color zinc
  • White Plating
  • Chrome Plated
  • Brass Plated
  • Anodized

Flat Washers Standards

DIN 125DIN 34815DIN 6916ISO 7093.1ISO 10669BS 4395DIN 1440ASTM F959
DIN 9021DIN 6902DIN 134ISO 7094ISO 10673BS 3410DIN 433UNI 5714
DIN 1052DIN 6903ISO 7089ISO 7415ISO 7091BS 4320DIN 436UNI 6592
DIN 1441DIN 7349ISO 7090ISO 7416JIS B 1256ANSI/ASME B18.2.6NF E25-522UNI 1750
DIN 7989UNI 6593ISO 7092ISO 8738JIS B 1258ANSI/ASME B18.22.1NF E25-511UNI 1734
EN 28738DIN 434EN 14399JIS B 1220JIS B 1186IFI 542DIN 435ASTM F436

Best Quality Flat Washers Supplier

51Fasteners supplies flat washers in various sizes and materials, we can customize the production according to your drawings, including: thin washers, thick washers, large OD flat washers, small OD flat washers, heavy duty flat washers, fender washers and so on.

Stainless Steel Flat Washer

Copper Flat Washer

Red Steel Paper Insulated Flat Washer

Titanium Flat Washer

Nylon Flat Washer

Features

  • Conforms to international standards
  • Highly refined surfaces
  • Protects connecting surfaces from damage
  • Prevents screws from loosening
  • Anti-fallout soft material
  • Various materials
  • Various surface treatments
  • Various specifications

Applications

  • Automotive
  • Construction
  • Electrical equipment
  • Furniture assembly
  • Industrial machinery
  • Household appliances
  • Marine & Offshore

Processing Service

  • Customized Size
  • Surface Treatment
  • Laser Cutting
  • Special Material
  • Laser Marking
  • Packaging Design
  • OEM/ODM

A Trusted Global Supplier of Flat Washers for Industry

51Fasteners has more than 10 years of experience in the fastener industry, ISO 9001 certified, and our products are exported to 50+ countries. We support small batch customization and mass production with stable delivery and reliable quality, and have provided cost-effective fastener solutions for hundreds of customers around the world.

  • Flat washer shipped direct from manufacturer
  • Standard flat washers in stock
  • Sturdy carton + wooden pallet for export
  • Support customized drawing
  • One-stop solution for fastener industry

Frequently Asked Questions

Distributes pressure, reduces friction, prevents loosening and protects connecting surfaces.

Yes, we offer environmentally friendly options such as lead-free galvanizing and Dacromet.

Stainless steel flat washers are not completely rustproof, 304/316 material may still rust in humid, salt spray or acidic environment.

  1. 304 Stainless Steel: Resistant to normal humid environments and virtually rust free.
  2. 316 stainless steel: more resistant to corrosion, suitable for marine or chemical environments.

Surface treatment: Passivation, electrolytic polishing or plating (e.g. nickel plating) to enhance protection.
Regular maintenance: apply rust preventive oil or grease in harsh environments.

Yes. Surface treatments can significantly enhance material properties.

  • Galvanized: anti-rust
  • Dacromet: corrosion resistance
  • Blackening: wear-resistant, anti-corrosion
  • Color zinc and copper plating: decoration and protection
  • Anodizing: aluminum fastener insulation, hardness enhancement, coloring
  • Nickel plating: enhances corrosion and abrasion resistance as well as surface finish.
  • White (galvanized): Provides basic rust protection and is commonly used for light industrial fittings.
  • Chrome plating: enhances hardness and abrasion resistance, bright and decorative surface finish

You can choose from a variety of logistics methods, such as sea freight, air freight, express delivery, and so on.

ItemFlat WasherFender Washer
Outer DiameterStandard sizeLarger outer diameter
Inner DiameterStandard hole (matches bolt size)Similar to flat washer, fits the bolt diameter
ThicknessStandard thicknessGenerally thinner