---
title: "Silicone (VMQ) O-Ring Seal"
description: "Silicone (VMQ) O-Ring Seal (vinyl-methyl silicone, typically 70 Shore A): inert and physiologically neutral; low tear and abrasion strength."
url: https://engineeringhardware.com/guide/material/silicone-cad-svg-159-oring/
source: Engineering Hardware & Fasteners
---

# Silicone (VMQ) O-Ring Seal

Seals · ISO / DIN

Temperature range, chemical and fluid compatibility, hardness and the full dimensional range for this compound.

Silicone (VMQ) O-Ring Seal are supplied to vinyl-methyl silicone, typically 70 Shore A. Corrosion behaviour is inert and physiologically neutral; low tear and abrasion strength, the material is non-magnetic, and the usable service range is approx. -60 °C to +200 °C. In practice this grade is used for wide temperature range and food/medical contact, in static seals only.

- **Grade:** vinyl-methyl silicone, typically 70 Shore A
- **Corrosion resistance:** Inert and physiologically neutral; low tear and abrasion strength
- **Magnetic response:** Non-magnetic
- **Service temperature:** approx. -60 °C to +200 °C

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

![Silicone (VMQ) O-Ring Seal reference image](https://engineeringhardware.com/wp-content/uploads/2026/06/O-Ring-Seal-—-ISO-DIN-Series-159-—-ISO-DIN.webp)

Material page for o-ring seal in Silicone (VMQ) (vinyl-methyl silicone, typically 70 Shore A). The sizes below are the ones we supply; there is no published dimensional standard for this article, so the table rather than a standard number is what to quote. Corrosion behaviour is inert and physiologically neutral; low tear and abrasion strength and the service range is approx. -60 °C to +200 °C.

## Why Choose Silicone (VMQ) for O-Ring Seal — ISO / DIN (Series 159)

Used for wide temperature range and food/medical contact, in static seals only. For o-ring seal — iso / din (series 159), this matters when inert and physiologically neutral; low tear and abrasion strength is the primary requirement.

## Mechanical & Physical Properties

| Grade designation | vinyl-methyl silicone, typically 70 Shore A |
| --- | --- |
| Magnetic response | Non-magnetic |
| Service temperature | approx. -60 °C to +200 °C |
| Corrosion characteristic | Inert and physiologically neutral; low tear and abrasion strength |

## Corrosion Behavior in Service

Carbon and alloy steel o-ring seal — iso / din (series 159) require a coating for corrosion protection. Zinc plating (with or without passivation) is the most common; hot-dip galvanizing is used for outdoor structural service; black-oxide is mainly a tarnish-prevention finish for tool-room use.

## Comparable Grades

For o-ring seal — iso / din (series 159), consider NBR or FKM wherever the seal is dynamic — silicone has low tear and abrasion strength and is a static-seal material. Elastomer selection is decided by the medium, the temperature range and whether the seal is static or dynamic — not by strength.

## Sizes of O-Ring Seal — ISO / DIN (Series 159) Available in Silicone (VMQ)

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

Dimensions are independent of the material: the table above lists the sizes supplied, and on this page every one of them is quoted in Silicone (VMQ). The catalogue's default material column has been omitted here so it cannot be read as contradicting that.

Custom manufacturing · Made to drawing

## Need this seal in a grade that is not listed?

Silicone 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](https://engineeringhardware.com/custom/seals/)[Send a drawing](https://engineeringhardware.com/custom/seals/#rfq)

## Technical Drawing

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

## 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](https://engineeringhardware.com/applications/cad-svg-159-oring/)

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.

1. ![Wire rod feeding into a cold heading machine](https://engineeringhardware.com/wp-content/uploads/2026/08/09-wire-rod-feed-cold-heading-machine.webp) 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.
2. ![Thread rolling machine producing bolt threads](https://engineeringhardware.com/wp-content/uploads/2026/08/03-thread-rolling-machine-bolt-production.webp) 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.
3. ![Baskets of bolts staged for heat treatment](https://engineeringhardware.com/wp-content/uploads/2026/08/05-heat-treatment-baskets-black-bolts.webp) 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.
4. ![Zinc plated bolts in a treatment basket](https://engineeringhardware.com/wp-content/uploads/2026/08/23-zinc-plated-bolts-treatment-basket.webp) 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 hardness are Silicone (VMQ) O-Ring Seal — ISO / DIN (Series 159) supplied in?

Shore A 70 is the general-purpose default. A softer compound (around 60) seals better on a rough or slightly out-of-round surface; a harder one (around 80 to 90) resists extrusion at higher pressure or across a wider gap. State the hardness on the order — it is not implied by the material.

### Does Silicone (VMQ) have a shelf life?

Yes. Elastomers age in storage as well as in service — keep them cool, dark, dry and away from ozone sources such as electric motors, and use stock in the order it arrived. PTFE is the exception and does not age this way.

### How much compression should Silicone (VMQ) o-ring seal — iso / din (series 159) see?

The groove or gland decides it, not the seal: a static radial seal is normally designed for roughly 15–30% compression on the section, and a dynamic one for less. Give us the groove dimensions and the pressure and we will confirm the section against them.

### What's the service temperature limit for Silicone (VMQ)?

The practical service range is approx. -60 °C to +200 °C.

### 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.

## Related Pages

[View the full O-Ring Seal — ISO / DIN (Series 159) page](https://engineeringhardware.com/fastener/cad-svg-159-oring/)

### More O-Ring Seal — ISO / DIN (Series 159) Guides