A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) is specified for marine, coastal and chemical applications. When hex weld nuts with flange are specified in this grade, the dimensions remain per ISO 21670; the material determines corrosion behavior (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). Both are covered below with the size table.
Why Choose A4 Stainless Steel for Hex Weld Nuts with Flange
Specified for marine, coastal and chemical applications. For hex weld nuts with flange, 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 weld nuts with flange: (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 Weld Nuts with Flange, the alternative stainless grade is A2 (304). The practical dividing line is chlorides: A2 (304) is fine until salt is involved, and A4 (316) exists for the cases where it is — coastal, marine and road-salt service. Neither reaches the strength of a plated class 8.8 or 10.9 fastener.
Using Stainless Fasteners in Aluminum
Expect the aluminum to corrode, not the fastener — stainless sits higher in the galvanic series, so the aluminum is the one that gives up material. A small fastener in a thick section spreads the loss over a large area and is usually fine; a large fastener in thin sheet concentrates it and is not. Keep water out of the joint, or isolate the two metals with a nylon or coated washer and a sealant.
Sizes of Hex Weld Nuts with Flange Available in A4 Stainless Steel
| Size | Pitch P (mm) | b (mm) | c (mm) | d_a (mm) | d_c (mm) | Width across corners e (mm) | f (mm) | g (mm) | m_min (mm) | Nut height m (mm) | Width across flats s (mm) | r_1 (mm) | r_2 (mm) | m1000 (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M5 | 0.8 | 2.2 | 0.8 | 6 | 15.5 | 8.2 | 1.7 | 4 | 4.7 | 5 | 8 | 0.6 | 0.3 | 2.9 | ISO 21670 |
| M6 | 1 | 2.7 | 0.8 | 7 | 18.5 | 10.6 | 2 | 5 | 6.64 | 7 | 10 | 0.6 | 0.5 | 5.7 | ISO 21670 |
| M8 | 1.25 | 2.7 | 1 | 9.5 | 22.5 | 13.6 | 2.5 | 6 | 9.64 | 10 | 13 | 0.8 | 0.8 | 12.2 | ISO 21670 |
| M8x1 | 1 | 2.7 | 1 | 9.5 | 22.5 | 13.6 | 2.5 | 6 | 9.64 | 10 | 13 | 0.8 | 0.8 | 12.2 | ISO 21670 |
| M10 | 1.5 | 2.95 | 1.2 | 11.5 | 26.5 | 16.9 | 3 | 7 | 12.57 | 13 | 16 | 1 | 1 | 21.8 | ISO 21670 |
| M10x1.25 | 1.25 | 2.95 | 1.2 | 11.5 | 26.5 | 16.9 | 3 | 7 | 12.57 | 13 | 16 | 1 | 1 | 21.8 | ISO 21670 |
| M10x1 | 1 | 2.95 | 1.2 | 11.5 | 26.5 | 16.9 | 3 | 7 | 12.57 | 13 | 16 | 1 | 1 | 21.8 | ISO 21670 |
| M12 | 1.75 | 3.2 | 1.2 | 14 | 30.5 | 19.4 | 3 | 8 | 14.57 | 15 | 18 | 1 | 1.2 | 29.4 | ISO 21670 |
| M12x1.5 | 1.5 | 3.2 | 1.2 | 14 | 30.5 | 19.4 | 3 | 8 | 14.57 | 15 | 18 | 1 | 1.2 | 29.4 | ISO 21670 |
| M12x1.25 | 1.25 | 3.2 | 1.2 | 14 | 30.5 | 19.4 | 3 | 8 | 14.57 | 15 | 18 | 1 | 1.2 | 29.4 | ISO 21670 |
| M14 | 2 | 3.45 | 1.2 | 16 | 33.5 | 22.4 | 4 | 8 | 16.16 | 17 | 21 | 1 | 1.2 | 45.8 | ISO 21670 |
| M14x1.5 | 1.5 | 3.45 | 1.2 | 16 | 33.5 | 22.4 | 4 | 8 | 16.16 | 17 | 21 | 1 | 1.2 | 45.8 | ISO 21670 |
| M16 | 2 | 3.7 | 1.2 | 18 | 36.5 | 25 | 4 | 8 | 18.66 | 19.5 | 24 | 1 | 1.2 | 63.1 | ISO 21670 |
| M16x1.5 | 1.5 | 3.7 | 1.2 | 18 | 36.5 | 25 | 4 | 8 | 18.66 | 19.5 | 24 | 1 | 1.2 | 63.1 | ISO 21670 |
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. 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.
