A2 Stainless Steel (ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70) is the most common stainless group for indoor and general outdoor fasteners. Specified on elastomer-sealing nuts it determines the corrosion behaviour (good general corrosion resistance) and the service temperature range (approx. -200 °C to +400 °C, subject to the property class and the joint); the dimensions are ours rather than a standard's, and are listed in full below.
Why Choose A2 Stainless Steel for Elastomer-Sealing Nuts
The most common stainless group for indoor and general outdoor fasteners. For elastomer-sealing nuts, this matters when good general corrosion resistance is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70 |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C, subject to the property class and the joint |
| Corrosion characteristic | Good general corrosion resistance |
Corrosion Behavior in Service
A2 (304) gives excellent atmospheric and most-water corrosion resistance and is the most common stainless for Elastomer-Sealing Nuts in indoor and general outdoor service. In chloride-bearing environments (marine air, road salt, swimming pools) consider stepping up to A4 (316).
Galvanic & Galling Considerations
Two important notes for stainless elastomer-sealing nuts: (1) stainless can gall on stainless threads under load — use a thread lubricant or anti-galling compound, especially for M6 and below; (2) when joined to aluminum or galvanized steel, stainless can drive galvanic corrosion of the less-noble metal in wet service — isolate with a coating or sleeve where appropriate.
Using Stainless Fasteners in Aluminum
Stainless steel is more noble than aluminum, so with an electrolyte present — rain, condensation, salt spray — the aluminum becomes the anode and corrodes at the joint. Area ratio decides how bad it gets: a small stainless fastener in a large aluminum section is normally acceptable, a large stainless fastener in thin aluminum is not. Where the joint gets wet, isolate the metals with a coated or nylon washer and a sealant, or specify an aluminum or coated fastener instead.
Sizes of Elastomer-Sealing Nuts Available in A2 Stainless Steel
| Thread size | Pitch (mm) | Sealing-rib height (mm) | Thread class | Temperature range (°C) | Finish |
|---|---|---|---|---|---|
| M3 | 0.5 | 0.2 | 6H | -75~+204 | zinc-chromate plated low-carbon steel |
| M4 | 0.7 | 0.3 | 6H | -75~+204 | zinc-chromate plated low-carbon steel |
| M5 | 0.8 | 0.4 | 6H | -75~+204 | zinc-chromate plated low-carbon steel |
| M6 | 1.0 | 0.5 | 6H | -75~+204 | zinc-chromate plated low-carbon steel |
| M8 | 1.25 | 0.6 | 6H | -75~+204 | zinc-chromate plated low-carbon steel |
| M10 | 1.5 | 0.6 | 6H | -75~+204 | zinc-chromate plated low-carbon steel |
| M12 | 1.75 | 0.8 | 6H | -75~+204 | zinc-chromate plated low-carbon steel |
| M14 | 2.0 | 6H | -75~+204 | zinc-chromate plated low-carbon steel |
Dimensions are independent of the material: the table above lists the sizes supplied, and on this page every one of them is quoted in A2 Stainless Steel. 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 nut in a grade that is not listed?
A2 Stainless Steel is one of the grades the catalog describes. Thread size is the obvious variable and rarely the interesting one — height for clearance, across-flats for the tool already in the cell, and the locking feature for the vibration actually present. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
