A4 Stainless Steel Tab Washers (DIN 93 / DIN 463) combine the dimensional form of DIN 93 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 Tab Washers (DIN 93 / DIN 463)
Specified for marine, coastal and chemical applications. For tab washers (din 93 / din 463), 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 tab washers (din 93 / din 463) 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 Tab Washers (DIN 93 / DIN 463), 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
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 Tab Washers (DIN 93 / DIN 463) Available in A4 Stainless Steel
| For bolt size | Inner diameter d1 (mm) | Outer diameter d2 (mm) | Thickness t (mm) | Tab length (mm) | Form | Material | Reference standard |
|---|---|---|---|---|---|---|---|
| M6 | 6.4 | 14.0 | 0.8 | 8 | Single tab (DIN 93) | Mild steel | DIN 93 |
| M8 | 8.4 | 18.0 | 1.0 | 10 | Single tab (DIN 93) | Mild steel | DIN 93 |
| M10 | 10.5 | 22.0 | 1.0 | 12 | Single tab (DIN 93) | Mild steel | DIN 93 |
| M12 | 13.0 | 26.0 | 1.25 | 14 | Single tab (DIN 93) | Mild steel | DIN 93 |
| M16 | 17.0 | 32.0 | 1.5 | 16 | Single tab (DIN 93) | Mild steel | DIN 93 |
| M20 | 21.0 | 40.0 | 2.0 | 20 | Single tab (DIN 93) | Mild steel | DIN 93 |
