Material specification page for compression spring in Grade 12.9 Steel. Covers the grade designation (class 12.9), corrosion and magnetic behavior, comparable grades and their trade-offs, and the sizes available to ISO / DIN.
Why Choose Grade 12.9 Steel for Compression Spring — ISO / DIN (Series 146)
The highest common strength class, for high-load machine assembly. For compression spring — iso / din (series 146), this matters when requires plating or black-oxide protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | class 12.9 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | up to approx. +300 °C |
| Corrosion characteristic | Requires plating or black-oxide protection |
Corrosion Behavior in Service
Carbon and alloy steel compression spring — iso / din (series 146) require a coating for corrosion protection. Zinc plating (with or without passivation) is the most common; hot-dip galvanizing is used for outdoor structural service; black-oxide is mainly a tarnish-prevention finish for tool-room use.
Comparable Grades
For Compression Spring — ISO / DIN (Series 146), class 8.8 is the comparable strength step. Move up when the joint preload approaches the proof load of the current class; move down when the joint is over-specified. For corrosion-critical service, switch to stainless A2 or A4.
Sizes of Compression Spring — ISO / DIN (Series 146) Available in Grade 12.9 Steel
| 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 |