Heat treatments are used to improve the properties of spring material. The table below gives the various treatments that ensure that the particular material is suitable for the required operating temperature.
| Material | Type | Coiling | Operating Temperature | Heat treatment after coiling |
|---|---|---|---|---|
| B-class | Spring hardness | Cold | Up to 200°C | 240°C for 1 hour + A.C. |
| C-class | Spring hardness | Cold | Up to 200°C | 240°C for 1 hour + A.C. |
| AISI 301 | Spring hardness | Cold | Up to 200°C | 240°C for 1 hour + A.C. |
| AISI 316 | Spring hardness | Cold | Up to 200°C | 240°C for 1 hour + A.C. |
| Monel 400 | Spring hardness | Cold | Up to 230°C | 300°C - 320°C for 0.5 - 1 hours + A.C. |
| K-Monel 500 | Spring hardness | Cold | Up to 260°C | 540°C for 4 hours + A.C. |
| Hastelloy C4 | Cold | Up to 450°C | 400°C - 450°C for 2 hours + A.C. | |
| Inconel 600 | Spring hardness | Cold | Up to 390°C | 460°C for 1 hour + A.C. |
| Inconel X750 | No 1 | Cold | Up to 540°C | 730°C for 16 hours + A.C. |
| Inconel X750 | Spring hardness | Cold | Up to 370°C | 650°C for 4 hours + A.C. |
| Inconel X750 | Spring hardness | Cold | 460°C - 705°C | 1150°C for 2 hours + 843°C for 24 hours + 704°C for 20 hours + A.C. |
| Nimonic 90 | Spring hardness | Cold | Up to 350°C | 650°C for 4 hours + A.C. |
| Nimonic 90 | Solution | Cold | 350°C-590°C | 750°C for 4 hours + A.C. |
