Colour Temperatures

The colour of a piece of steel may be used as a guide to it's temperature. These are particulalrly useful when hardening or tempering steel.

Colour	°C
Pale yellow	221
Straw	230
Golden yellow	243
Brown	254
Brown to purple	266
Purple	277
Bright blue	288
Blue	293
Dark blue	316
Just visible red	500 to 600
Dull cherry red	700 to 750
Cherry red	750 to 825
Bright cherry red	825 to 875
Brightest red	900 to 950
Orange	950 to 1000
Light orange	1000 to 1050
Lemon	1100 to 1200
White	1200 to 1300

Note: These should only be used as a guide.

See also: Colour, Heat Treatment, Temper, Temper Colours, Temperature.