Heating and cooling to produce a spherical or globular form of carbide in steel.
Spherodizing methods frequently used are:
1. Prolonged holding at a temperature just below Ae1. .
2. Heating and cooling alternately between temperatures that are just below Ae1. .
3. Heating to temperature above Ae1 or Ae3 and then cooling very slowly in the furnace or holding at a temperature just below Ae1. .
4. Cooling at a suitable rate from the minimum temperature at which all carbide is dissolved, to prevent the reformation of a carbide network, and then re-heating in accordance with methods 1 or 2 above. (Applicable to hypereutectoid steel containing a carbide network.