Allowable torsional stresses
| Steel grade | Allowable torsional shear stress τa [MPa] | |
|---|---|---|
| d < 8 mm | d = [8…40] mm | |
| 51VCr11A | 650 | 600 |
| 60Si15A | 680 | 650 |
| 56Si15A | 630 | 500 |
| 51Si17A | 600 | 480 |
| C55A | 550 | 500 |
| C65A | 500 | 460 |
| C75A | 550 | 500 |
| C85A | 560 | 520 |
Note. d is the wire diameter; for high-precision springs, allowable stresses τa 25% higher than those in the table are recommended.