A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) is specified for marine, coastal and chemical applications. Specified on adhesive-mount nuts it determines the corrosion behaviour (superior, including marine and chloride environments) 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 A4 Stainless Steel for Adhesive-Mount Nuts
Specified for marine, coastal and chemical applications. For adhesive-mount nuts, this matters when superior, including marine and chloride environments is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80 |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C, subject to the property class and the joint |
| Corrosion characteristic | Superior, including marine and chloride environments |
Corrosion Behavior in Service
A4 (316) adds 2–3% molybdenum to the A2 (304) composition, which dramatically improves resistance to chloride-pitting corrosion. For Adhesive-Mount Nuts in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Galvanic & Galling Considerations
Two important notes for stainless adhesive-mount 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 Adhesive-Mount Nuts Available in A4 Stainless Steel
| Thread options | Base form | Round base diameter (mm) | Rectangular base (mm) | Base thickness (mm) | Nut width examples (mm) | Material |
|---|---|---|---|---|---|---|
| 4-40 / 6-32 / 1/4-20 / 5/16-18 / 3/8-16 | round | 23 or 38 | 1.2 | 8.8 / 9.9 / 10.8 / 13.8 / 16.8 | 316 stainless steel | |
| M4 / M5 / M6 / M8 / M10 / M12 | rectangular | 24×11.5 or 38×15 | 1.2 | 8.8 / 9.9 / 10.8 / 13.8 / 16.8 | 316 stainless steel |
Dimensions are independent of the material: every size above is available in A4 Stainless Steel.
Custom manufacturing · Made to drawing
Need this nut in a grade that is not listed?
A4 Stainless Steel is one of the grades the catalog describes. Height and across-flats are the two most often changed — a thinner nut for clearance, a larger hex for a tool that is already on the line. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
