Square Washers Manufacturer
MT.BOLTS manufactures Square Washers, which are essential flat fastener components designed to provide a wide bearing surface under bolt or nut heads. Their square shape prevents turning and distributes load evenly over a larger surface area, making them especially suitable for timber structures, channel steel connections, and heavy-duty bolting applications. Square washers are commonly used in construction, structural steelwork, utility installations, and marine hardware. MT.BOLTS offers square washers in a variety of sizes, materials, and finishes to meet international engineering and safety standards.
- System of Measurement:
- Metric: M6 – M64
- Imperial: 1/4″ to 2.5″
- Washer Dimensions (General):
- Thickness: Metric: 1.5 mm – 12 mm | Imperial: 1/16″ – 1/2″
- Inner Hole: Round or square, sized to bolt diameter
- Outer Dimensions: Typically larger than round washers for improved load distribution
- Square Washer Types:
- DIN 7989 Square Washer – Standard for steel construction
- ASTM F436 Square Structural Washer – Hardened washer for heavy bolting
- Flat Square Washers – General-purpose use
- Beveled Square Washers – For channel or beam flanges
- Oversized / Thick Square Washers – Custom dimensions for structural assemblies
- Custom Cut Washers – According to drawing or project specification
Square Washers Material Types
MT.BOLTS supplies carbon steel, stainless steel, duplex steel, and nickel-based alloy Square Washers , meeting the demanding requirements of chemical, marine, and high-temperature environments, compliant with various international standards.
| Material Category | Common Grades/Models | Description |
| Carbon Steel | ASTM A307, A325, A490 | High strength and cost-effective, suitable for general structures; requires anti-corrosion coating. |
| Stainless Steel | 304 (A2), 316 (A4), 321, 410 | Excellent corrosion resistance; widely used in food, chemical, and construction industries |
| Duplex Stainless Steel | UNS S31803/S32205 (F51), UNS S32750 (F53) | High strength with superior chloride corrosion resistance; used in seawater, petrochemical, and paper industries |
| Monel Alloys | Monel 400, Monel K500 | Excellent seawater corrosion resistance and mechanical strength; used in marine engineering and pump systems |
| Hastelloy Alloys | Hastelloy C276, C22, B2, X | Excellent resistance to strong acids and oxidizing media; widely used in chemical equipment and flue gas desulfurization |
| Inconel Alloys | Inconel 600, 625, 718 | Resistant to high temperature, pressure, and corrosion; used in heat exchangers, aerospace, and nuclear industries |
| Incoloy Alloys | Incoloy 800, 825, 925 | Ideal for high-temperature acidic environments; widely used in petroleum refining and heat treating systems |
| Nickel Alloys | Nickel 200, 201 | Pure or high-nickel alloys with excellent conductivity and alkali resistance; used in electronics and chemical applications |
Square Washers System of Measurement
Square washers are manufactured in both metric and imperial measurement systems to accommodate a variety of construction, structural, and fastening applications:
Metric Sizes: M6 to M64
Imperial Sizes: 1/4″ to 2-1/2″
Thickness Range: 1.5 mm to 12 mm (metric) | 1/16″ to 1/2″ (imperial)
Inner Hole Types: Round or square, sized to bolt diameter
Outer Dimensions: Typically larger than standard round washers for increased bearing area
Square Washers Common Standards
Square washers are produced in compliance with major international standards for structural and general-purpose use:
ASTM F436 – Hardened steel square structural washers
ASTM A36 / A108 – General carbon steel material specifications
DIN 7989 – Square flat washers for steel constructions (metric)
ISO 7094 – Oversized washers with larger OD
ASME B18.22.1 – Standard washer dimensions and tolerances
Custom / OEM Standards – For special sizes, materials, or coatings
Square Washers Surface Finishes
To meet different environmental and application needs, square washers are available with a wide range of surface treatments:
Plain (Uncoated) – For indoor or non-corrosive use
Zinc-Plated – Moderate corrosion protection (clear or yellow chromate)
Hot-Dip Galvanized – Ideal for outdoor, marine, or structural use
Black Oxide – For light protection and an aesthetic black finish
Phosphate-Coated – Improves paint adhesion and corrosion resistance
PTFE-Coated / Epoxy / Painted – For color-coding, chemical resistance, or special environments
Stainless Steel / Electropolished – For food-grade or corrosive environments
Why Choose MT.BOLTS
- Material Diversity
- Standardized Production
- Ample Inventory
- Competitive Pricing
- Low-MOQ Customization
Benefits and Limitations of Square Washers
Benefits:
Wider Load Distribution: Provides a larger contact surface than round washers, ideal for use on softer materials like wood.
Anti-Rotation Stability: The four-corner design helps prevent washer rotation during installation.
Structural Reinforcement: Suitable for structural joints, enhancing the transmission of bolt tension.
Customizable: Can be manufactured to specific dimensions, thicknesses, or materials based on project drawings.
Limitations:
Not Suitable for Tight Spaces: The larger shape may not fit well in confined or narrow installation spaces.
Less Common in General Machinery: Used less frequently in standard mechanical equipment compared to round washers.
May Require Alignment: Installation may require directional positioning for proper alignment with workpieces.
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Square Washers Applications
Square washers are commonly used in:
Timber Construction: Prevents bolts from embedding into wood, offering greater support.
Structural Steel Bolting: Used in beam, column, or plate joints for structural reinforcement.
Utility Poles & Towers: Provides structural anchoring in power and communication towers.
Rail and Bridge Construction: Suitable for heavy-load and vibration-resistant environments.
Marine & Offshore Hardware: Ideal for anti-corrosion and structural support needs.
Custom Engineering Projects: Designed to meet project-specific size and material requirements.
FAQ About Square Washers
Square washers provide more surface area and better anti-rotation properties, making them ideal for wood and structural applications.
Yes, as long as the inner hole size matches the bolt diameter. They are especially useful with carriage bolts and structural bolts.
Yes. MT.BOLTS offers square washers in stainless steel, carbon steel, hot-dip galvanized, and other finishes.
Common standards include ASTM F436, DIN 7989, and ISO custom specs depending on region and use case.
Absolutely. Custom dimensions, hole shapes, materials, and coatings are available based on drawings or application needs.
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