For t-slot nuts in A4 Stainless Steel, the controlling selection factors are corrosion exposure, strength requirement and service temperature. The grade data for A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) is summarized below together with every size supplied.
Why Choose A4 Stainless Steel for T-Slot Nuts
Specified for marine, coastal and chemical applications. For t-slot 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 T-Slot Nuts in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Galvanic & Galling Considerations
Two important notes for stainless t-slot 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 in the presence of an electrolyte — rain, condensation, salt spray — the aluminum becomes the anode and corrodes at the joint. The effect is driven by the area ratio: a small stainless fastener in a large aluminum section is normally acceptable, while a large stainless fastener in thin aluminum is not. Where the joint is wet, isolate the two metals with a coated or nylon washer and a sealant, or specify an aluminum or coated fastener instead.
Sizes of T-Slot Nuts Available in A4 Stainless Steel
| Thread size | T-slot width (mm) | Nut width b (mm) | Total height h (mm) | Key height h1 (mm) | Hook width e (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M5 | 6 | 8.0 | 8.0 | 4.5 | 6.4 | DIN 508 / GN505 |
| M6 | 8 | 10.0 | 10.0 | 5.5 | 8.4 | DIN 508 / GN505 |
| M8 | 10 | 12.0 | 12.0 | 7.0 | 10.4 | DIN 508 / GN505 |
| M8 | 12 | 14.0 | 12.0 | 7.0 | 12.4 | DIN 508 / GN505 |
| M10 | 12 | 14.0 | 14.0 | 8.0 | 12.4 | DIN 508 / GN505 |
| M10 | 14 | 16.0 | 14.0 | 8.0 | 14.4 | DIN 508 / GN505 |
| M12 | 14 | 16.0 | 17.0 | 10.0 | 14.4 | DIN 508 / GN505 |
| M12 | 18 | 20.0 | 17.0 | 10.0 | 18.4 | DIN 508 / GN505 |
| M16 | 18 | 20.0 | 20.0 | 12.0 | 18.4 | DIN 508 / GN505 |
| M16 | 22 | 25.0 | 20.0 | 12.0 | 22.4 | DIN 508 / GN505 |
| M20 | 22 | 25.0 | 25.0 | 15.0 | 22.4 | DIN 508 / GN505 |
| M20 | 28 | 32.0 | 25.0 | 15.0 | 28.4 | DIN 508 / GN505 |
| M24 | 28 | 32.0 | 30.0 | 18.0 | 28.4 | DIN 508 / GN505 |
