A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) is specified for marine, coastal and chemical applications. Specified on wheel nuts, conical and ball seat 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 Wheel Nuts, Conical and Ball Seat
Specified for marine, coastal and chemical applications. For wheel nuts, conical and ball seat, 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 Wheel Nuts, Conical and Ball Seat in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Galvanic & Galling Considerations
Two important notes for stainless wheel nuts, conical and ball seat: (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 Wheel Nuts, Conical and Ball Seat Available in A4 Stainless Steel
| Thread size | Pitch (mm) | Seat type | Width across flats s (mm) | Total height m (mm) | Typical torque (Nm) | Material | Finish |
|---|---|---|---|---|---|---|---|
| M12 | 1.25 | Conical 60° | 17 | 20 | 110 | Class 10 steel | Zinc / chrome cap |
| M12 | 1.5 | Conical 60° | 19 | 20 | 110 | Class 10 steel | Zinc / chrome cap |
| M12 | 1.5 | Ball / radius R13 | 19 | 20 | 110 | Class 10 steel | Zinc / chrome cap |
| M14 | 1.5 | Conical 60° | 19 | 24 | 140 | Class 10 steel | Zinc / chrome cap |
| M14 | 1.5 | Ball / radius R14 | 21 | 24 | 140 | Class 10 steel | Zinc / chrome cap |
| M22 | 1.5 | Conical 60° | 32 | 32 | 600 | Class 10 steel | Zinc, commercial vehicle |
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.
