Faculty Advisor

Sisson, Richard D.


Grain growth during heat treatment has a negative effect on fatigue. As a result, grain growth kinetics have been determined for 4140 steel in order to predict the effective time for heat treating. A series of samples were heat treated at 850 oC and 900 oC and held for 60, 120 and 180 minutes. It was experimentally determined that grain growth kinetics were faster for samples with a higher austenizing temperature. Diffusivity growth constants were found to be 2.682E-06 (mm2/min) for the samples heated at 900C and 1.902E-06 (mm2/min) for those treated at 850C. The maximum heating time before the deterioration of the material properties, namely fatigue, was calculated to be 510min at 850oC and 442min at 900oC.


Worcester Polytechnic Institute

Date Accepted

April 2008


Mechanical Engineering

Project Type

Major Qualifying Project



Advisor Department

Mechanical Engineering