Mechanical properties, corrosion behaviour and the full dimensional range for this grade.
A4 Stainless Steel USIT Rings (Self-Centring Bonded Seals) are supplied to ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80. Corrosion behaviour is superior, including marine and chloride environments, the material is largely non-magnetic, and the usable service range is approx. -200 °C to +400 °C, subject to the property class and the joint. In practice this grade is specified for marine, coastal and chemical applications.
Property values are typical for the grade. Certified mechanical test data is available on request for production orders.
A4 Stainless Steel is not a material usit rings (self-centring bonded seals) are supplied in. USIT Rings (Self-Centring Bonded Seals) are threaded fasteners, and this combination does not describe a part that exists.
The materials that do apply are: NBR (Nitrile), FKM (Viton®-type), EPDM, Silicone (VMQ), PTFE.
See the USIT Rings (Self-Centring Bonded Seals) product page for the specifications that do apply →
Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.
The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.
| Thread | Seal element | Metal carrier | Typical service |
|---|---|---|---|
| M6 | NBR inner lip | zinc-plated steel | hydraulic ports and plugs |
| M8 | NBR inner lip | zinc-plated steel | hydraulic ports and plugs |
| M10 | NBR inner lip | zinc-plated steel | hydraulic ports and plugs |
| M12 | NBR inner lip | zinc-plated steel | hydraulic ports and plugs |
| M14 | NBR or FKM inner lip | zinc-plated or stainless | hydraulic and fuel |
| M16 | NBR or FKM inner lip | zinc-plated or stainless | hydraulic and fuel |
| M18 | NBR or FKM inner lip | zinc-plated or stainless | hydraulic |
| M20 | NBR or FKM inner lip | zinc-plated or stainless | hydraulic |
| M22 | NBR inner lip | zinc-plated steel | hydraulic |
| M27 | NBR inner lip | zinc-plated steel | hydraulic |
USIT Rings are bought for a small number of well-defined jobs. These are the ones we ship them for. Stocked from M6 to M27.
This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.
Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.
Head dimensions and under-head radius checked at set-up and per shift.
Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.
Go / no-go ring gauges to ISO 965 tolerance class 6g.
Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.
Core hardness and tensile tested per lot to ISO 898-1.
Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.
Coating thickness and neutral salt spray hours to ISO 9227.
Only at the standard strength classes — A2-70 / A4-80 are roughly equivalent to class 7 steel; A4-100 reaches class 8.8. For class 10.9 or 12.9 strength, plated alloy steel is required.
A4 Stainless Steel USIT Rings (Self-Centring Bonded Seals) are largely non-magnetic.
A4 Stainless Steel USIT Rings (Self-Centring Bonded Seals) provide superior, including marine and chloride environments with a service range of approx. -200 °C to +400 °C, subject to the property class and the joint.
For USIT Rings (Self-Centring Bonded Seals), A4 Stainless Steel suits general indoor and outdoor use; A2 (304) is preferred for marine, coastal and chemical environments. Choose by corrosion exposure first.
Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.
