Original position statistic distribution analysis for the sulfides in gear steels

Abstract

The sulfides in some different gear steels were analyzed by original position statistic distribution analysis technique. The relationship between the proportion of the frequency of high intensity signals and the content of total sulfur and total oxygen in samples has been investigated. Multi-elemental correlation on high intensity signals has been performed in order to obtain the composition and proportion of different type of sulfides. It was found that the proportion of simple sulfide was more than that of oxide-sulfide duplex inclusion in six gear steel samples. The ratio of the oxide-sulfide duplex inclusion to the total sulfides were determined by the present method and the results had good coincidence with the value obtained by quantitative metallographic method and scanning electronic microscopy. The influence of the content of Ca on the composition of the sulfides was investigated. It was found that the relative proportion of the complex inclusions of Al-Ca-Mn-O-S increase with the rise of the content of Ca in gear steels. The ratio of the content of Ca to the content of S (Ca/S) also had great effect on the relative proportion of the oxide-sulfide duplex inclusion. © 2014 ISIJ.