A4 Stainless Steel Hex Thick Nuts (DIN 6330) combine the dimensional form of DIN 6330 with the material properties of grade ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80: superior, including marine and chloride environments, largely non-magnetic, service range approx. -200 °C to +400 °C, subject to the property class and the joint. This page summarizes the grade data, its corrosion behavior in service, the comparable grades, and the sizes supplied.
Why Choose A4 Stainless Steel for Hex Thick Nuts (DIN 6330)
Specified for marine, coastal and chemical applications. For hex thick nuts (din 6330), 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 |
Galvanic & Galling Considerations
Two important notes for stainless hex thick nuts (din 6330): (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.
Comparable Grades
For Hex Thick Nuts (DIN 6330), the alternative stainless grade is A2 (304). A2 (304) covers general indoor and outdoor service. A4 (316) adds molybdenum, which is what buys the chloride resistance for marine and de-icing-salt exposure. Where strength matters more than corrosion, plated alloy steel in class 8.8 or 10.9 is the swap to make.
Using Stainless Fasteners in Aluminum
The galvanic couple here runs the wrong way: aluminum is the less noble metal, so it corrodes and the fastener does not. What governs the rate is the ratio of areas — a large anode and a small cathode is a tolerable combination, the reverse concentrates the attack into thin material around the hole. An isolating washer plus sealant breaks the circuit; where that is impractical, match the fastener to the substrate.
Sizes of Hex Thick Nuts (DIN 6330) Available in A4 Stainless Steel
| Thread size | Pitch (mm) | Width across flats s (mm) | Nut height m (mm) | Height ratio m/d | Engaged threads | Property class | Reference standard |
|---|---|---|---|---|---|---|---|
| M8 | 1.25 | 13.0 | 12.0 | 1.5 | approx. 9.6 | 10 | DIN 6330 |
| M10 | 1.5 | 17.0 | 15.0 | 1.5 | approx. 10.0 | 10 | DIN 6330 |
| M12 | 1.75 | 19.0 | 18.0 | 1.5 | approx. 10.3 | 10 | DIN 6330 |
| M16 | 2.0 | 24.0 | 24.0 | 1.5 | approx. 12.0 | 10 | DIN 6330 |
| M20 | 2.5 | 30.0 | 30.0 | 1.5 | approx. 12.0 | 10 | DIN 6330 |
| M24 | 3.0 | 36.0 | 36.0 | 1.5 | approx. 12.0 | 10 | DIN 6330 |
