Copper Sealing Washers (DIN 7603 A) manufactured in A2 Stainless Steel (ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70) are dimensioned to DIN 7603. The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.
Why Choose A2 Stainless Steel for Copper Sealing Washers (DIN 7603 A)
The most common stainless group for indoor and general outdoor fasteners. For copper sealing washers (din 7603 a), 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 Copper Sealing Washers (DIN 7603 A) 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 Copper Sealing Washers (DIN 7603 A), 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 Copper Sealing Washers (DIN 7603 A) Available in A2 Stainless Steel
| Inner diameter d1 (mm) | Outer diameter d2 (mm) | Thickness t (mm) | Material | Condition | Max temperature (u00b0C) | Reference standard | Re-use |
|---|---|---|---|---|---|---|---|
| 6.0 | 10.0 | 1.0 | Cu-DHP | Soft annealed | 250 | DIN 7603 | Single use |
| 8.0 | 12.0 | 1.0 | Cu-DHP | Soft annealed | 250 | DIN 7603 | Single use |
| 10.0 | 14.0 | 1.5 | Cu-DHP | Soft annealed | 250 | DIN 7603 | Single use |
| 12.0 | 16.0 | 1.5 | Cu-DHP | Soft annealed | 250 | DIN 7603 | Single use |
| 14.0 | 20.0 | 1.5 | Cu-DHP | Soft annealed | 250 | DIN 7603 | Single use |
| 16.0 | 22.0 | 2.0 | Cu-DHP | Soft annealed | 250 | DIN 7603 | Single use |
| 20.0 | 26.0 | 2.0 | Cu-DHP | Soft annealed | 250 | DIN 7603 | Single use |
