For square flat washers (gb/t 96) in A2 Stainless Steel, the controlling selection factors are corrosion exposure, strength requirement and service temperature. The grade data for A2 Stainless Steel (ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70) is summarized below together with every size supplied.
Why Choose A2 Stainless Steel for Square Flat Washers (GB/T 96)
The most common stainless group for indoor and general outdoor fasteners. For square flat washers (gb/t 96), 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 Square Flat Washers (GB/T 96) in indoor and general outdoor service. In chloride-bearing environments (marine air, road salt, swimming pools) consider stepping up to A4 (316).
Galvanic & Galling Considerations
For stainless square flat washers (gb/t 96) 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
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 Square Flat Washers (GB/T 96) Available in A2 Stainless Steel
| Bolt size | Material | Finish options | Typical use |
|---|---|---|---|
| M8 | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / yellow zinc / hot-dip galvanized | steel brackets and guardrails |
| M10 | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / yellow zinc / hot-dip galvanized | solar supports and curtain walls |
| M12 | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / yellow zinc / hot-dip galvanized | embedded connections |
| M16 | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / hot-dip galvanized | embedded and structural connections |
Dimensions are independent of the material: every size above is available in A2 Stainless Steel.
Custom manufacturing · Made to drawing
Need this washer in a grade that is not listed?
A2 Stainless Steel is one of the grades the catalog describes. Bearing area is usually the reason for a special washer: a larger outside diameter to spread load into a softer material, or a thicker section to resist dishing. Made by stamping or punching.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
