The table below lists the dimensions catalogued for heavy hex socket head cap screw under ASTM A325. The scope of ASTM A325 itself is not summarised here — where a figure matters, confirm it against the published document.
ASTM A325 — Scope
The table below lists the dimensions catalogued for heavy hex socket head cap screw — gb/t 1228 / astm a325 (series 046) under ASTM A325. The scope of ASTM A325 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 ASTM A325. Tolerances for this part are the limits shown against each dimension in the table.
Dimensions Specified by ASTM A325
| Size | Pitch (mm) | Length L (mm) | Head diameter dk (mm) | Head height k (mm) | Hex socket s (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M3 | 0.5 | 20 | 5.5 | 3 | 2.5 | ISO 4762 / GB/T 70.1 |
| M4 | 0.7 | 25 | 7.0 | 4 | 3.0 | ISO 4762 / GB/T 70.1 |
| M5 | 0.8 | 30 | 8.5 | 5 | 4.0 | ISO 4762 / GB/T 70.1 |
| M6 | 1.0 | 40 | 10.0 | 6 | 5.0 | ISO 4762 / GB/T 70.1 |
| M8 | 1.25 | 50 | 13.0 | 8 | 6.0 | ISO 4762 / GB/T 70.1 |
| M10 | 1.5 | 60 | 16.0 | 10 | 8.0 | ISO 4762 / GB/T 70.1 |
| M12 | 1.75 | 80 | 18.0 | 12 | 10.0 | ISO 4762 / GB/T 70.1 |
| M14 | 2.0 | 80 | 21.0 | 14 | 12.0 | ISO 4762 / GB/T 70.1 |
| M16 | 2.0 | 100 | 24.0 | 16 | 14.0 | ISO 4762 / GB/T 70.1 |
| M18 | 2.5 | 100 | 27.0 | 18 | 14.0 | ISO 4762 / GB/T 70.1 |
| M20 | 2.5 | 120 | 30.0 | 20 | 17.0 | ISO 4762 / GB/T 70.1 |
| M24 | 3.0 | 150 | 36.0 | 24 | 19.0 | ISO 4762 / GB/T 70.1 |
| M30 | 3.5 | 180 | 45.0 | 30 | 22.0 | ISO 4762 / GB/T 70.1 |
| M36 | 4.0 | 200 | 54.0 | 36 | 27.0 | ISO 4762 / GB/T 70.1 |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Heavy Hex Socket Head Cap Screw — GB/T 1228 / ASTM A325 (Series 046) page.
Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
Companion Standards
A complete specification for heavy hex socket head cap screw — gb/t 1228 / astm a325 (series 046) normally cites several documents: one for the geometry, one for the material or mechanical properties, and one for the finish. ASTM A325 is one of them, not all of them.
Custom manufacturing · Made to drawing
Need a screw to this standard in a non-standard size?
Parts built to ASTM A325 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 cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
