GB/T 96 specifies the dimensions and tolerances for square flat washers (gb/t 96). The full dimensional table is reproduced below, followed by the DIN, ISO and ASME parts that match or supersede it.
- Standard
- GB/T 96
- Product
- Square Flat Washers (GB/T 96)
- Governing standards
- GB/T 96
Equivalence between national standards is dimensional, not always metallurgical. Check the property class separately when substituting.
GB/T 96 is the standard cited for square flat washers (gb/t 96). This page sets out what the standard controls for this part, reproduces the dimensional table supplied against it, and notes the related designations referenced on drawings.
GB/T 96 — Scope
The table below lists the dimensions catalogued for square flat washers (gb/t 96) under GB/T 96. The scope of GB/T 96 itself is not summarised here — where a figure matters, confirm it against the published document.
Tolerance & Product Grades
Product grade is a concept from dimensional fastener standards and does not apply to GB/T 96. Tolerances for this part are the limits shown against each dimension in the table.
Dimensions Specified by GB/T 96
| Bolt size | Material | Finish options | Typical use |
|---|
| M8 | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / yellow zinc / hot-dip galvanized | steel brackets and guardrails |
| M10 | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / yellow zinc / hot-dip galvanized | solar supports and curtain walls |
| M12 | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / yellow zinc / hot-dip galvanized | embedded connections |
| M16 | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / hot-dip galvanized | embedded and structural connections |
Companion Standards
A complete specification for square flat washers (gb/t 96) normally cites several documents: one for the geometry, one for the material or mechanical properties, and one for the finish. GB/T 96 is one of them, not all of them.
When to Specify GB/T 96
Choose GB/T 96 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for square flat washers (gb/t 96).
Custom manufacturing · Made to drawing
Need a washer to this standard in a non-standard size?
Parts built to GB T 96 are already in the catalog, so a special is usually a variation on existing tooling rather than a new design — which is what keeps the cost down. Made by stamping or punching.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
Custom washer manufacturingSend a drawing
Applications & Industries
The sectors that buy Square Flat Washers to GB/T 96, and the duty each one buys them for. Stocked from M8 to M16 (nominal bolt size).
Industries that specify Square Flat Washers
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Guardrail and barrier
Wide bearing area spreads bolt load into thin members.
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Curtain walling
Galvanized options for exposed facade fixings.
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Embedded connections
Large bearing face on cast-in assemblies.
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Solar mounting
Square washers seat against square holes in support rails.
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Machine building & OEM
Setting bearing area on soft alloy, plastic and oversized holes.
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Timber & construction
Large-diameter washers that stop pull-through in softer material.
Typical applications
- spreading bolt load over a thin or soft member
- choosing hot-dip galvanizing for exposed positions
- checking the washer is not confused with the thicker DIN 436 plate washer
- matching the square outside to a square mounting hole
- protecting a painted or plated surface under a turned nut
- maintaining bolt tension in a joint that settles
Service conditions to specify against
- Marine and coastal
- Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
- Exterior structural
- Hot-dip galvanised options for external steelwork; allow for the thicker coating in the mating thread.
- Hardness matters
- Under a high-strength bolt a soft washer embeds into the joint and preload is lost — specify a hardened washer for structural bolting.
Where to use something else
- Do not substitute a round washer where the hole is square; the corners are what stop it rotating into the slot.
Full application guide: where Square Flat Washers are used, how to specify them, and the cases they are wrong for
