Color-of-heat term from the forge and toolroom for the deep red glow of steel at about 750 to 800 °C. Hotter steel shows bright cherry around 830 °C, orange around 900 to 950 °C and yellow above 1,000 °C. Perceived color shifts badly with shop lighting, so it is a rough guide for hand work, never a replacement for a thermocouple or pyrometer.
Heard on the job
Bring the chisel tip up to cherry red, then dunk just the edge and let the heat run back.
Also heard as
- cherry heat
Related terms
Magnet test
Checking steel with a magnet while heating, since it stops being magnetic near its hardening temperature.
Austenitizing
Heating steel above its upper critical temperature and holding it until the structure becomes austenite.
Temper colors
Thin oxide colors, from pale straw to blue, that form on clean steel as it is heated in air.