Annealing treatment for medium- and high-carbon steels in which parts are held just below Ac1, or cycled around it, for many hours so cementite plates break up and ball into spheroids in a ferrite matrix. It gives the softest, most machinable and most formable condition for steels like 52100 and 1095, and a spheroidized starting structure also hardens more evenly with less distortion.
Race tubing has to come in spheroidized, if it's pearlitic the screw machines eat tools all day.
Also heard as
- spheroidize anneal
- spheroidize annealing
- spheroidized
Related terms
Annealing
Heating metal and cooling it slowly to soften it, relieve stress and make it easier to machine or form.
Cementite
Iron carbide, Fe3C: the hard, brittle compound that carries most of the carbon in slowly cooled steel.
Carbide
Any hard compound of carbon with iron or alloying elements such as chromium, vanadium, molybdenum or tungsten.
Pearlite
A layered mix of ferrite and cementite that forms when austenite cools slowly through the eutectoid range.