For Spiral-Wound Metal Gasket — GB/T 4622 / ASME B16.20 (Series 090), T 4622 defines dimensions, tolerances and product grades. The sections below describe its scope, what it does NOT cover, and the equivalents across DIN, ISO and ASME.
T 4622 — Scope
T 4622 specifies the dimensions and tolerances of spiral-wound metal gasket — gb/t 4622 / asme b16.20 (series 090). Material, property class, surface finish and packaging are governed by separate documents in the same standards family (for example ISO 898-1 for the mechanical property classes of bolts and screws).
Tolerance & Product Grades
T 4622, alongside the related GB/T 4622 / ASME B16.20 entries on this site, specifies product grades (typically A or B for fine work and C for general engineering) and tolerance classes for the controlling dimensions. Choose the grade against the precision your application requires.
Dimensions Specified by 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 T 4622
Choose 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).