For clip-on nuts (sheet metal speed 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 Clip-On Nuts (Sheet Metal Speed Nuts)
Specified for marine, coastal and chemical applications. For clip-on nuts (sheet metal speed 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 Clip-On Nuts (Sheet Metal Speed Nuts) in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Galvanic & Galling Considerations
Two important notes for stainless clip-on nuts (sheet metal speed 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
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 Clip-On Nuts (Sheet Metal Speed Nuts) Available in A4 Stainless Steel
| Thread size | Panel thickness (mm) | Clip length (mm) | Clip width (mm) | Hole centre from edge (mm) | Panel hole (mm) | Material | Finish |
|---|---|---|---|---|---|---|---|
| M3 | 0.7~1.6 | 14 | 10 | 6.5 | 4.5 | Spring steel | Zinc plated |
| M4 | 0.7~1.6 | 17 | 12 | 8.0 | 5.5 | Spring steel | Zinc plated |
| M5 | 0.7~2.0 | 20 | 14 | 9.5 | 7.0 | Spring steel | Zinc plated |
| M6 | 1.0~2.5 | 24 | 16 | 11.0 | 8.5 | Spring steel | Zinc plated |
| M8 | 1.0~3.0 | 30 | 20 | 14.0 | 11.0 | Spring steel | Zinc plated |
