For spiral-wound metal gasket, GB/T 4622 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 4622 — Scope
GB/T 4622 specifies the dimensional requirements for spiral-wound metal gasket — gb/t 4622 / asme b16.20 (series 090). 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 spiral-wound metal gasket — gb/t 4622 / asme b16.20 (series 090) 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 4622
| Nominal pipe size | Inner diameter d1 (mm) | Outer diameter d2 (mm) | Thickness t (mm) | Winding material | Reference standard |
|---|---|---|---|---|---|
| DN15 | 22 | 42 | 4.5 | 304SS + flexible graphite | GB/T 4622 / ASME B16.20 |
| DN20 | 27 | 49 | 4.5 | 304SS + flexible graphite | GB/T 4622 / ASME B16.20 |
| DN25 | 34 | 59 | 4.5 | 304SS + flexible graphite | GB/T 4622 / ASME B16.20 |
| DN32 | 43 | 69 | 4.5 | 304SS + flexible graphite | GB/T 4622 / ASME B16.20 |
| DN40 | 49 | 75 | 4.5 | 304SS + flexible graphite | GB/T 4622 / ASME B16.20 |
| DN50 | 61 | 87 | 4.5 | 304SS + flexible graphite | GB/T 4622 / ASME B16.20 |
| DN65 | 77 | 109 | 4.5 | 304SS + flexible graphite | GB/T 4622 / ASME B16.20 |
| DN80 | 89 | 121 | 4.5 | 304SS + flexible graphite | GB/T 4622 / ASME B16.20 |
| DN100 | 115 | 149 | 4.5 | 304SS + flexible graphite | GB/T 4622 / ASME B16.20 |
| DN150 | 169 | 205 | 4.5 | 304SS + flexible graphite | GB/T 4622 / ASME B16.20 |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Spiral-Wound Metal Gasket — GB/T 4622 / ASME B16.20 (Series 090) page. Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify GB/T 4622
Choose GB/T 4622 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for spiral-wound metal gasket — gb/t 4622 / asme b16.20 (series 090).


