For Extension Springs, DIN 2097 defines dimensions, tolerances and product grades. The sections below describe its scope, what it does NOT cover, and the equivalents across DIN, ISO and ASME.
DIN 2097 — Scope
DIN 2097 specifies the dimensions and tolerances of extension springs. Material, property class, surface finish and packaging are governed by separate documents in the same standards family (for example ISO 898-1 for the mechanical property classes of bolts and screws).
Tolerance & Product Grades
DIN 2097, alongside the related DIN 2097 entries on this site, specifies product grades (typically A or B for fine work and C for general engineering) and tolerance classes for the controlling dimensions. Choose the grade against the precision your application requires.
Dimensions Specified by DIN 2097
| 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 |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Extension Springs page. Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify DIN 2097
DIN 2097 is still widely used in European mechanical engineering and as a cross-reference on legacy drawings; its ISO equivalent is preferred for new designs.