A2 Stainless Steel Extension Springs are stocked to DIN 2097. The grade provides good general corrosion resistance and is largely non-magnetic; the practical service range is approx. -200 °C to +400 °C. Property data, grade comparison and the full size table follow.
Why Choose A2 Stainless Steel for Extension Springs
The most common stainless grade for indoor and general outdoor fasteners. For extension springs, this matters when good general corrosion resistance is the primary requirement.
Mechanical & Physical Properties
| Grade designation | A2-70 (304) |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C |
| 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 Extension Springs 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
Two important notes for stainless extension springs: (1) stainless can gall on stainless threads under load — use a thread lubricant or anti-galling compound, especially for M6 and below; (2) when joined to aluminum or galvanized steel, stainless can drive galvanic corrosion of the less-noble metal in wet service — isolate with a coating or sleeve where appropriate.
Sizes of Extension Springs Available in A2 Stainless Steel
| Wire dia d (mm) | Inner diameter Di (mm) | Outer diameter De (mm) | Free length Lo (mm) | Active coils n | Initial tension Fi (N) | Rate k (N/mm) | Material | Reference standard |
|---|---|---|---|---|---|---|---|---|
| 0.5 | 3.5 | 4.5 | 20 | 12 | 10 | 0.7 | Spring steel | DIN 2097 / EN 15800 |
| 0.6 | 4.5 | 5.7 | 25 | 12 | 15 | 1.2 | Spring steel | DIN 2097 / EN 15800 |
| 0.8 | 5.5 | 7.1 | 30 | 12 | 30 | 2.5 | Spring steel | DIN 2097 / EN 15800 |
| 1.0 | 7.0 | 9.0 | 40 | 15 | 45 | 3.5 | Spring steel | DIN 2097 / EN 15800 |
| 1.2 | 8.5 | 10.9 | 50 | 15 | 70 | 6.0 | Spring steel | DIN 2097 / EN 15800 |
| 1.5 | 11.0 | 14.0 | 60 | 15 | 100 | 8.0 | Spring steel | DIN 2097 / EN 15800 |
| 2.0 | 13.0 | 17.0 | 80 | 15 | 200 | 16.0 | Spring steel | DIN 2097 / EN 15800 |
| 2.5 | 17.0 | 22.0 | 100 | 15 | 380 | 30.0 | Spring steel | DIN 2097 / EN 15800 |
| 3.0 | 22.0 | 28.0 | 120 | 15 | 680 | 55.0 | Spring steel | DIN 2097 / EN 15800 |
| 4.0 | 28.0 | 36.0 | 160 | 15 | 1500 | 120.0 | Spring steel | DIN 2097 / EN 15800 |
| 5.0 | 36.0 | 46.0 | 200 | 15 | 2900 | 210.0 | Spring steel | DIN 2097 / EN 15800 |
| 6.0 | 46.0 | 58.0 | 250 | 15 | 5200 | 380.0 | Spring steel | DIN 2097 / EN 15800 |