ČSN EN ISO 4885 - Železné materiály – Tepelné zpracování – Slovník

3.213 transformation temperature

temperature at which a change of phase (3.156) occurs and, by extension, at which the transformation begins and ends when the transformation occurs over a range of temperatures Note1 to entry: The following principal transformation temperatures can be distinguished in steels: — A1, equilibrium temperature defining the lower limit of existence of austenite (3.12); — A3, equilibrium temperature defining the upper limit of existence of ferrite (3.85); — Am, equilibrium temperature defining the upper limit of existence of cementite (3.39) in hypereutectoid steels (3.117); — Ms, temperature at which the austenite begins to transform into martensite (3.137) during cooling (3.45); — Mf, temperature at which the austenite has almost completely transformed into martensite during cooling; — Mx, temperature at which x vol.-% of the austenite has transformed into martensite during cooling.