EFFECT OF ALLOYING ON TEMPERATURE OF TRANSFORMATION «PEARLITE – AUSTENITE» IN COMPLEX-ALLOYED WHITE CAST IRONS

Authors

DOI:

https://doi.org/10.15802/stp2015/38255

Keywords:

complex-alloyed cast iron, the critical point, chromium, vanadium, vanadium carbides, pearlite, austenite, phase transformation

Abstract

Purpose. Pearlite is not accepted in the microstructure of wear resistant steels and cast irons. To prevent the pearlite by means of appropriate selection of mode of quenching requires the knowledge of the temperature of the critical points Ac1 and Ac3 for various steels and cast irons. Purpose of work is determine the effect of V (5-10%) and Cr (up to 9%) on the temperature range of the phase-structural transformation "pearlite®austenite in the complex-alloyed V-Cr-Mn-Ni white cast irons with spheroidal vanadium carbides. Methodology. Nine Mg-treated cast irons smelted in laboratory furnace were used for investigation. The metallographic and optical dilatometric analysis methods as well as energy-dispersive spectroscopy were used. Findings. It is shown that in irons studied the critical point Ac1 is in a temperature range from 710-780 °C (lower limit) up to 730-850 °C (upper limit). The data on the concentrations of chromium and vanadium in a matrix of iron are presented, the regression equation describing the effect of vanadium and chromium on the temperature limits of the transformation «pearlite ® austenite» are obtained. Originality. It is shown that increase the chromium content leads to growth of lower and upper limits of the temperature interval of transformation "pearlite ® austenite"; vanadium increases only the upper limit of the range. It was found that the effect of chromium on the critical point Ac1 is attributed to its solubility in the metallic matrix (concentration of Cr in the austenite reaches 7%); vanadium, due to its slight dissolution in the matrix (vanadium content does not exceed 1.75%), affects the critical point indirectly by increasing of chromium concentration in the matrix due to enhanced carbon sequestration in VC carbides. Practical value. The temperature ranges of heating for quenching of V-Cr-Mn-Ni cast irons with spheroidal vanadium carbides, which provides the formation of austenitic-martensitic matrix without pearlite, is transformation proposed.

Author Biographies

T. V. Pastukhova, Pryazovsk State Technical University

Dep. «Metal Science and Heat Treatment of Metals»

V. G. Efremenko, Pryazovsk State Technical University

Dep. «Physics»

A. P. Cheiliakh, Pryazovsk State Technical University

Dep. «Metal Science and Heat Treatment of Metals»

K. Shimizu, Muroran Institute of Technology

K. Shimizu

Yu. G. Chabak, Pryazovsk State Technical University

Dep. «Physics»

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Published

2015-02-26

How to Cite

Pastukhova, T. V., Efremenko, V. G., Cheiliakh, A. P., Shimizu, K., & Chabak, Y. G. (2015). EFFECT OF ALLOYING ON TEMPERATURE OF TRANSFORMATION «PEARLITE – AUSTENITE» IN COMPLEX-ALLOYED WHITE CAST IRONS. Science and Transport Progress, (1(55), 113–121. https://doi.org/10.15802/stp2015/38255

Issue

Section

MATERIAL SCIENCE