(Three major categories + need to sort out common material grades for different countries + whether XY is available for supply)
| Steel grade | Grade | Recommended maximum operating temperature |
| Carbon steel (alloy spring steel) | 65Mn | 120℃ |
| 72B | 200℃ | |
| 50CrVA | 300℃ | |
| 60Si2MnA | 250℃ | |
| Stainless steel | SUS304 | 500℃ |
| SUS316 | 800℃ | |
| SUS410 | 700℃ | |
| SUS630 | 300℃ | |
| SUS631 | 300℃ | |
| Superalloy steel | Hast.C276 | 1000℃ |
| INCONEL 625 | 950℃ | |
| INCONEL X-750 | 800℃ | |
| INCONEL 718 | 700℃ | |
| INCOLOY A286 | 800℃ |
