To slow the metal's critical cooling rate
to approximately 1 [degree] C to 100 [degrees] C per second, "we realized we had to go to a very complicated material," said Johnson the Ruben and Donna Mettler Professor of Engineering and Applied Science at Caltech.
Results also show that a critical cooling rate
of about 33.
A physical model for the evaluation of chill formation in iron castings was developed, based on the concept of a critical cooling rate
at which a gray to white transition occurs.
With the calculated casting temperature history known, a comparison of simulated cooling rates with critical cooling rates
necessary to obtain certain microstructures can be used to determine the microstructure distribution in the casting after quenching.