during the forging process you get grain growth in the steel as well as stresses
excessive grain growth makes for weak steel.
thermal cycling helps reduce the grain structure as well as alleviating some of the stresses.
after forging I heat to 1 color past critical temp (non magnetic) I hold with tongs and in a darker room you will se the steel start to lose color and then the color comes back
this is the grain reducing and producing its own heat. allow the steel to cool to black heat.
second heat I heat to barely non magnetic and allow to cool the same as the first cycle.
third cycle heat to just under non magnetic and allow to cool to black heat
fourth heat to barely non magnetic and quench in room temp used motor oil and wha-la it should be hard but not brittle
if ya have any more questions feel free to give me a call on by cell after 4pm est on the week days or anytime during daylight hours on weekends
(231) 460-3738
Kevin
