Material specification page for push-on nuts (starlock retainers) in A2 Stainless Steel. Covers the grade designation (ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70), corrosion and magnetic behavior, comparable grades and their trade-offs, and the sizes available to Trade series (push-on retaining washer).
Why Choose A2 Stainless Steel for Push-On Nuts (Starlock Retainers)
The most common stainless group for indoor and general outdoor fasteners. For push-on nuts (starlock retainers), this matters when good general corrosion resistance is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70 |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C, subject to the property class and the joint |
| Corrosion characteristic | Good general corrosion resistance |
Corrosion Behavior in Service
A2 (304) gives excellent atmospheric and most-water corrosion resistance and is the most common stainless for Push-On Nuts (Starlock Retainers) in indoor and general outdoor service. In chloride-bearing environments (marine air, road salt, swimming pools) consider stepping up to A4 (316).
Comparable Grades
For Push-On Nuts (Starlock Retainers), the alternative stainless grade is A4 (316). Choose A2 (304) for general use and A4 (316) wherever chlorides are present; the molybdenum in A4 is the whole difference. Remember that stainless is the corrosion answer, not the strength answer — for load, look at class 8.8 or 10.9 instead.
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 Push-On Nuts (Starlock Retainers) Available in A2 Stainless Steel
| For shaft diameter (mm) | Outer diameter (mm) | Thickness (mm) | Teeth | Push-off resistance (N, typical) | Material | Finish | Reusable |
|---|---|---|---|---|---|---|---|
| 3.0 | 11.0 | 0.25 | 12 | 150 | Spring steel | Bright zinc | No |
| 4.0 | 12.0 | 0.25 | 12 | 220 | Spring steel | Bright zinc | No |
| 5.0 | 15.0 | 0.30 | 12 | 320 | Spring steel | Bright zinc | No |
| 6.0 | 18.0 | 0.30 | 12 | 420 | Spring steel | Bright zinc | No |
| 8.0 | 21.0 | 0.40 | 12 | 600 | Spring steel | Bright zinc | No |
| 10.0 | 26.0 | 0.40 | 12 | 780 | Spring steel | Bright zinc | No |
