The Austenitizing Behavior of a Low Alloy Steel

The austenitizing behavior of a low alloy steel was examined from both the microstructural and the mechanical property standpoint. The temperature range over which austenitizing took place was accurately determined by metallographic and analytical techniques. Metallographic evidence showed that the dissolution of carbide continues after the crystallographic transition is completed. Also, the dissolution of the preponderance of carbide coincides with a leveling-off trend in mechanical property response, viz., yield strength and Charpy impact toughness. The data demonstrated that a minimum temperature of 774 C 1425 F can sufficiently austenitize this steel under the appropriate conditions. However, because of chemical segregation invariably found in large forgings, it is a sound practice to allow some contingency in the heat treatment parameters that will consistently provide an adequate austenitizing condition in the thickest sections of a component.