A regression equation for the Ar3 temperature for as-cast ferrite/pearlite steels has been
obtained. At these coarse grain sizes, very little influence of grain size on the Ar3 is observed. Out of all the elements examined, C, Mn and Nb had the major influence in decreasing the
Ar3. A change in cooling rate from 10 to 200K/min results in only a small decrease of around
25oC. Of particular interest is the very marked effect of Nb in reducing the Ar3, an addition of
0.03%Nb causing a decrease in the Ar3 of 55oC.