| HEAT TREATMENT TEMPERATURES FOR CARBON STEEL | |||||||
| Temperature | Colour of Glowing Steel | ||||||
| Fahrenheit | Centigrade | ||||||
| 2350 | 1288 | Dazzling White | |||||
| 2200 | 1204 | White | |||||
| 1975 | 1079 | Light Yellow | |||||
| 1825 | 996 | Lemon | |||||
| 1725 | 941 | Orange | |||||
| 1650 | 899 | Salmon and Scaling | |||||
| 1550 | 843 | Bright Red and Scaling |
Note that Steel becomes non-magnetic while heating at about 780-820
deg C but while cooling at a different temperature
|
||||
| 1375 | 746 | Cherry Red | |||||
| 1250 | 677 | Medium Cherry Red | |||||
| 1075 | 579 | Dark Cherry Red | |||||
| 1050 | 566 | Blood Red | |||||
| 900 | 482 | Faint red (GLOW) | |||||
| Temperature | Surface colour of polished Steel | HARDNESS | TYPICAL APPLICATIONS | ||||
| Fahrenheit | Centigrade | ||||||
| 750 | 400 | Grey | |||||
| 610 | 321 | Pale blue | 53Rc | ||||
| 567 | 297 | Bright Blue | 55Rc | Cheap Kitchen knives | |||
| 550 | 287 | Dark Blue | 56Rc | Springs | |||
| 531 | 277 | Purple | 57Rc | Cold Chisels, punches | |||
| 509 | 265 | Brown & Purple | 58Rc | ||||
| 491 | 255 | Brown | 59Rc | Taps and Scribers | |||
| 469 | 243 | Gold Yellow/Straw | 60Rc | ||||
| 428 | 220 | Pale Yellow | 61Rc | ||||
| 400 | 200 | Very Pale Yellow | 62Rc | Woodturning tools | |||