ISO is the governing dimensional standard for compression spring. This page sets out the scope of the standard, reproduces the full size table it specifies, and lists the DIN/ISO/ASME cross-references commonly cited in datasheets and drawings.
ISO — Scope
ISO specifies the dimensions and tolerances of compression spring — iso / din (series 145). 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
ISO, alongside the related ISO / DIN 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 ISO
| Wire dia d (mm) | Outer diameter De (mm) | Free length Lo (mm) | Rate k (N/mm) | Rated force Fn (N) | Material | Reference standard |
|---|---|---|---|---|---|---|
| 0.6 | 5.2 | 20 | 1.5 | 12 | Music wire / chrome silicon | DIN 2098 / GB/T 23934 |
| 0.8 | 6.6 | 25 | 2.5 | 22 | Music wire / chrome silicon | DIN 2098 / GB/T 23934 |
| 1.0 | 8.0 | 30 | 3.5 | 35 | Music wire / chrome silicon | DIN 2098 / GB/T 23934 |
| 1.2 | 10.4 | 40 | 6.0 | 55 | Music wire / chrome silicon | DIN 2098 / GB/T 23934 |
| 1.6 | 15.2 | 60 | 8.5 | 90 | Music wire / chrome silicon | DIN 2098 / GB/T 23934 |
| 2.0 | 20.0 | 80 | 18.0 | 165 | Music wire / chrome silicon | DIN 2098 / GB/T 23934 |
| 2.5 | 25.0 | 100 | 28.0 | 260 | Music wire / chrome silicon | DIN 2098 / GB/T 23934 |
| 3.0 | 30.0 | 120 | 45.0 | 450 | Music wire / chrome silicon | DIN 2098 / GB/T 23934 |
| 4.0 | 40.0 | 150 | 90.0 | 1000 | Music wire / chrome silicon | DIN 2098 / GB/T 23934 |
| 5.0 | 50.0 | 200 | 170 | 1900 | Music wire / chrome silicon | DIN 2098 / GB/T 23934 |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Compression Spring — ISO / DIN (Series 145) page. Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify ISO
Choose ISO for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for compression spring — iso / din (series 145).