Seals · ISO / DIN

A2 (304) Stainless Steel O-Ring Seal

Mechanical properties, corrosion behaviour and the full dimensional range for this grade.

A2 Stainless Steel O-Ring Seal are supplied to ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70. Corrosion behaviour is good general corrosion resistance, 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 the most common stainless group for indoor and general outdoor fasteners.

Grade: ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70
Corrosion resistance: Good general corrosion resistance
Magnetic response: Largely non-magnetic
Service temperature: approx. -200 °C to +400 °C, subject to the property class and the joint

Property values are typical for the grade. Certified mechanical test data is available on request for production orders.

A2 Stainless Steel is not a material o-ring seal are supplied in. O-Ring Seal are specified by inside diameter, 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 O-Ring Seal product page for the specifications that do apply →

Custom manufacturing · Made to drawing

Need this seal in a grade that is not listed?

A2 Stainless Steel is one of the grades the catalog describes. Inside diameter, cross-section and compound are the three that matter, and the compound is chosen against the fluid and the temperature rather than the dimensions.

Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

Custom seal manufacturing Send a drawing

Technical Drawing

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.

Dimensioned line drawing of 5 O-Ring Seal — ISO / DIN (Series 159). Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected.

Outer diameter d2 (mm): 9
Wire dia (mm): 2
Material: NBR 70
Working temp range: -30 to +110 C

Sends the selected values to the quote form below.

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The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.

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Specification

Item / category Standard Size(s) Material / finish Quantity

Business Information

Company * Contact Name * Email * Phone (with country code) Country / Region

Notes

Dimensions & Specifications (ISO / DIN)

Inner diameter d1 (mm)	Outer diameter d2 (mm)	Wire dia (mm)	Material	Working temp range	Reference standard
5	9	2	NBR 70	-30 to +110 C	ISO 3601 / GB/T 3452
8	12	2	NBR 70	-30 to +110 C	ISO 3601 / GB/T 3452
10	16	3	NBR 70	-30 to +110 C	ISO 3601 / GB/T 3452
15	21	3	NBR 70	-30 to +110 C	ISO 3601 / GB/T 3452
20	26	3	NBR 70	-30 to +110 C	ISO 3601 / GB/T 3452
25	33	4	NBR 70	-30 to +110 C	ISO 3601 / GB/T 3452
30	38	4	NBR 70	-30 to +110 C	ISO 3601 / GB/T 3452
40	50	5	NBR 70	-30 to +110 C	ISO 3601 / GB/T 3452
50	60	5	NBR 70	-30 to +110 C	ISO 3601 / GB/T 3452
60	72	6	NBR 70	-30 to +110 C	ISO 3601 / GB/T 3452
80	92	6	NBR 70	-30 to +110 C	ISO 3601 / GB/T 3452
100	114	7	NBR 70	-30 to +110 C	ISO 3601 / GB/T 3452

Applications & Industries

O-Ring Seal are bought for a small number of well-defined jobs. These are the ones we ship them for. Stocked from 5 to 100 (inside diameter).

Industries that specify O-Ring Seal

Process & food equipment Sealing at joints that are cleaned and inspected.
Hydraulics & pneumatics Static and dynamic sealing in cylinders and valve bodies.

Typical applications

excluding dust and moisture from a housing
sealing a joint against fluid or air pressure

Service conditions to specify against

Sealed joints: Used where the fixing has to keep water or air out as well as hold — the elastomer, not the fastener, decides service life.

Full application guide: where O-Ring Seal are used, how to specify them, and the cases they are wrong for

Video: A2 (304) Stainless Steel O-Ring Seal

The Different Between O'Ring Boss and O'Ring Face Sealing SAE Fittings

Third-party video, selected automatically for this topic. It is not produced by Engineering Hardware and is not a specification source — use the tables on this page for dimensional data.

Inside the plant

Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

01

Cold heading

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.
02

Thread rolling

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.
03

Heat treatment

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.
04

Surface treatment

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.

Frequently Asked Questions

What's the service temperature limit for A2 Stainless Steel?

The practical service range is approx. -200 °C to +400 °C, subject to the property class and the joint.

Can A2 Stainless Steel replace plated alloy steel structurally?

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.

Are A2 Stainless Steel O-Ring Seal — ISO / DIN (Series 159) magnetic?

A2 Stainless Steel O-Ring Seal — ISO / DIN (Series 159) are largely non-magnetic.

What corrosion resistance do A2 Stainless Steel O-Ring Seal — ISO / DIN (Series 159) offer?

A2 Stainless Steel O-Ring Seal — ISO / DIN (Series 159) provide good general corrosion resistance with a service range of approx. -200 °C to +400 °C, subject to the property class and the joint.

How do I request a quotation?

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.