Question

How would you expect an increase in the austenite grain size to affect the hardenability of a steel alloy? Why?

Answer 1

The hardenability increases with increasing austenite grain size, because the grain boundary area is decreasing. This means that the sites for the nucleation of ferrite and pearlite are being reduced in number, with the result that these transformations are slowed down, and the hardenability is therefore increased.