A4 Stainless Steel Wedge-Lock Washer Pairs combine the dimensional form of Trade series (cam wedge-lock pair) 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 Wedge-Lock Washer Pairs
Specified for marine, coastal and chemical applications. For wedge-lock washer pairs, 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
For stainless wedge-lock washer pairs the compatibility question is galvanic rather than galling: joined to aluminum or galvanized steel in wet service, stainless drives corrosion of the less-noble metal. Isolate with a coating, sleeve or non-conductive washer where the joint sees moisture. Note also that stainless is softer than hardened carbon steel, so where the part carries a wear or shear duty, check the load against the grade before substituting.
Comparable Grades
For Wedge-Lock Washer Pairs, 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
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 Wedge-Lock Washer Pairs Available in A4 Stainless Steel
| For bolt size | Inner diameter d1 (mm) | Outer diameter d2 (mm) | Thickness of pair t (mm) | Cam angle | Fits property class up to | Material | Re-use |
|---|---|---|---|---|---|---|---|
| M6 | 6.4 | 10.8 | 2.5 | approx. 12u00b0 | 12.9 | Hardened steel, Delta Protekt | Yes, teeth permitting |
| M8 | 8.7 | 13.5 | 3.4 | approx. 12u00b0 | 12.9 | Hardened steel, Delta Protekt | Yes, teeth permitting |
| M10 | 10.7 | 16.6 | 3.4 | approx. 12u00b0 | 12.9 | Hardened steel, Delta Protekt | Yes, teeth permitting |
| M12 | 13.0 | 19.5 | 4.0 | approx. 12u00b0 | 12.9 | Hardened steel, Delta Protekt | Yes, teeth permitting |
| M16 | 17.0 | 25.4 | 4.6 | approx. 12u00b0 | 12.9 | Hardened steel, Delta Protekt | Yes, teeth permitting |
| M20 | 21.4 | 30.7 | 5.2 | approx. 12u00b0 | 12.9 | Hardened steel, Delta Protekt | Yes, teeth permitting |
