CIV. Studies of continuous phase transformations with x-rays

A method due to Heal and Savage (1949) and described in detail by Heal and Mýkura (1950) has been developed to study the progress of the transformation of austenite (a) into martensite as the temperature falls below the Ms point, and (b) under isothermal conditions at temperatures below the Ms point. The martensite results do not agree entirely with an empirical formula of Cohen (1951); the isothermal results show how these transformations are changed markedly by the addition of 1 or 2% of alloying elements. The two sets of results are combined to draw the ‘S-curves’ below the Ms point for the steels EN24, EN26 and EN30B.