Kinetics and Microstructural Control

· The T-T-T diagram for the 4340 alloy also shows distinct noses for the bainite and pearlite transitions. These move to longer times than the combined nose of a plane carbon steel.
· Because the carbon content differs from the eutectoid concentration, this hypoeutectoid alloy will precipitate ferrite above the eutectoid invariant temperature.
· The M_S temperature is the same as for the 1080 carbon steel

From: Callister, "Materials Science & Engineering," Wiley (1994)