Temper colors from an older Machinery's Handbook, all in Fahrenheit;
430° = Very Pale Yellow
440° = Light Yellow
450° = Pale Straw Yellow
470° = Deep Straw Yellow
490° = Yellow-Brown
500° = Brown-Yellow
510° = Spotted Red-Brown
520° = Brown-Purple
530° = Light Purple
540° = Full Purple
550° = Dark Purple
560° = Full Blue
570° = Dark Blue
Note that as the heat raises most of these changes are very subtle & requires a very experienced eye for "Precision" control.
It should also be noted these colors were cited using plain carbon steels, some alloys will cause variations.
Last edited by 2-piper; 03/30/09 08:54 AM.
