Dilatometric examination of continuously heated austenite formation in hypoeutectoid steels

Abstract

Purpose: of this work is to present possibility of proper determination of pearlite dissolution finish temperature Ac1f during heating of hypoeutoctoid steels. Design/methodology/approach: The presented schemes of splitting the first derivative curve of hypoeutectoid steels dilatograms are based on experimental dilatograms and their first derivatives obtained by use of the dilatometric technique. Findings: The nine possible schemes of splitting the first derivative curve of hypoeutectoid steels dilatograms were developed. These schemes have been developed for three main cases: ferrite to austenite transformation temperature range is wider than for pearlite to austenite transformation, ferrite to austenite transformation temperature range has the same width as for the pearlite to austenite transformation and ferrite to austenite transformation temperature range is shorter than for pearlite to austenite transformation. Presented schemes are fully compatible with experimental results. Research limitations/implications: Further verification of correctness of the presented schemes and the development of appropriate curve fitting software is needed. Practical implications: Broadening the knowledge on the phase transformation kinetics of hypoeutectoid steels during heating. The basics for the automate process of determination of critical temperatures in steels, especially the Ac1f temperature, were established. Originality/value: The originally schemes of splitting the first derivative curve of hypoeutectoid steels dilatograms were developed.