text: there are many shapes of carbon, such as diamond, graphite, soccer ball and spheroidal.\n\nMost carbon formations in metal have to do the cooling rate of the liquid metal to the solid forms. Some really hard steels are cooled rapidly (a few seconds) from molten to a bit under 300 degrees celcius and then held there for days then allowed to cool slowly.\n\nOther are cooled to room temperature rapidly (less than half a minute) then reheated to a few hundred degrees (this is called tempering).\n\nI studied materials science over 15 years ago, and I can not recal the exact process for spheroidal graphite. I can't even remeber now if it is the same thing as pearlite. If you can not find the answer on the net, go to a library and look up books with titles like "engineering materials"