For square channel-steel washer, GB/T 852 is the governing document for the dimensions listed below. Mechanical and performance requirements for this part family are set by its own standards, not by the bolt and screw property-class documents.
GB/T 852 — Scope
GB/T 852 specifies the dimensional requirements for square channel-steel washer — gb/t 852 (series 083). Material, surface condition and any performance rating are set by separate documents specific to this part family — ISO 898-1 and ISO 898-2, which govern bolt and nut property classes, do not apply here.
Tolerance & Product Grades
Tolerances for square channel-steel washer — gb/t 852 (series 083) are given as limits on the individual dimensions in the table rather than as a fastener product grade. Where a general-tolerance class is cited on the drawing instead, it applies to the dimensions not otherwise toleranced.
Dimensions Specified by GB/T 852
| For bolt size | Inner diameter d1 (mm) | Outer diameter d2 (mm) | Thickness t (mm) | Reference standard |
|---|---|---|---|---|
| M3 | 3.2 | 7.0 | 0.5 | ISO 7089 / GB/T 97.1 |
| M4 | 4.3 | 9.0 | 0.8 | ISO 7089 / GB/T 97.1 |
| M5 | 5.3 | 10.0 | 1.0 | ISO 7089 / GB/T 97.1 |
| M6 | 6.4 | 12.0 | 1.6 | ISO 7089 / GB/T 97.1 |
| M8 | 8.4 | 16.0 | 1.6 | ISO 7089 / GB/T 97.1 |
| M10 | 10.5 | 20.0 | 2.0 | ISO 7089 / GB/T 97.1 |
| M12 | 13.0 | 24.0 | 2.5 | ISO 7089 / GB/T 97.1 |
| M14 | 15.0 | 28.0 | 2.5 | ISO 7089 / GB/T 97.1 |
| M16 | 17.0 | 30.0 | 3.0 | ISO 7089 / GB/T 97.1 |
| M18 | 19.0 | 34.0 | 3.0 | ISO 7089 / GB/T 97.1 |
| M20 | 21.0 | 37.0 | 3.0 | ISO 7089 / GB/T 97.1 |
| M24 | 25.0 | 44.0 | 4.0 | ISO 7089 / GB/T 97.1 |
| M30 | 31.0 | 56.0 | 4.0 | ISO 7089 / GB/T 97.1 |
| M36 | 37.0 | 66.0 | 5.0 | ISO 7089 / GB/T 97.1 |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Square Channel-Steel Washer — GB/T 852 (Series 083) page. Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify GB/T 852
Choose GB/T 852 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for square channel-steel washer — gb/t 852 (series 083).

