For flat washers, small series 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 Flat Washers, Small Series
Specified for marine, coastal and chemical applications. For flat washers, small series, 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 Flat Washers, Small Series in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Galvanic & Galling Considerations
For stainless flat washers, small series 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.
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 Flat Washers, Small Series Available in A4 Stainless Steel
| Size | Inner diameter d1 (mm) | Outer diameter d2 (mm) | Thickness h (mm) | h_max (mm) | Reference standard |
|---|---|---|---|---|---|
| M1.6 | 1.7 | 3.5 | 0.3 | 0.35 | ISO 7092 |
| M2 | 2.2 | 4.5 | 0.3 | 0.35 | ISO 7092 |
| M2.5 | 2.7 | 5.0 | 0.5 | 0.55 | ISO 7092 |
| M3 | 3.2 | 6.0 | 0.5 | 0.55 | ISO 7092 |
| M4 | 4.3 | 8.0 | 0.5 | 0.55 | ISO 7092 |
| M5 | 5.3 | 9.0 | 1.0 | 1.1 | ISO 7092 |
| M6 | 6.4 | 11.0 | 1.6 | 1.8 | ISO 7092 |
| M8 | 8.4 | 15.0 | 1.6 | 1.8 | ISO 7092 |
| M10 | 10.5 | 18.0 | 1.6 | 1.8 | ISO 7092 |
| M12 | 13.0 | 20.0 | 2.0 | 2.2 | ISO 7092 |
| M16 | 17.0 | 28.0 | 2.5 | 2.7 | ISO 7092 |
| M20 | 21.0 | 34.0 | 3.0 | 3.3 | ISO 7092 |
| M24 | 25.0 | 39.0 | 4.0 | 4.3 | ISO 7092 |
| M30 | 31.0 | 50.0 | 4.0 | 4.3 | ISO 7092 |
| M36 | 37.0 | 60.0 | 5.0 | 5.6 | ISO 7092 |
Dimensions are independent of the material: every size above is available in A4 Stainless Steel.
Custom manufacturing · Made to drawing
Need this washer in a grade that is not listed?
A4 Stainless Steel is one of the grades the catalog describes. Bore, outside diameter, thickness, temper and finish are the variables here — there is no thread to specify, so the fit and the bearing area are what the drawing has to pin down. Made by stamping or punching.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
