Method for measuring particle size of inclusion in metal by emission spectrum intensity of element constituting inclusion in metal, and method for forming particle size distribution of inclusion in metal, and apparatus for executing that method

Abstract

An electron probe microanalyzer determines the particle size of intermetallic inclusions in a master while scanning an area of phi5 mm located at an arbitrary location on the surface of the master. A calibration curve representative of the relationship between the particle size of intermetallic inclusions and the emission spectrum intensity of an constituent element constituting intermetallic inclusions is generated based on the determined particle size of the intermetallic inclusions. Intermetallic inclusions existing on emission spots on the surface of a test sample are specified based on data of emission spectrum intensity of an element existing on the emission spots, and a particle size of the specified intermetallic inclusions is determined based on the data of emission spectrum intensity and the generated calibration curve.

Description

[0001] This invention relates to a method of determining particle sizes of non-metallic inclusions dispersed in metal materials (hereinafter referred to as an "intermetallic inclusions") based on emission spectrum intensities of constituent elements of the intermetallic inclusions, and a method of generating particle size distributions of the intermetallic inclusions, as well as to apparatuses for performing the methods, and more particularly to a method of determining particle sizes of intermetallic inclusions based on emission spectrum intensities of constituent elements of the intermetallic inclusions by using an emission spectral analysis method, and a method of generating particle size distributions of intermetallic inclusions, as well as to apparatuses for performing the methods.[0002] In general, a steel material contains various kinds of intermetallic inclusions dispersed therein. The compositions as well as the particle sizes of the compositions and the particle size distri...

AI Technical Summary

Benefits of technology

0059] FIGS. 26A and 26B are diagrams useful in comparison between an Al.sub.2O.sub.3 particle size distribution (a) generated by execution of the FIG. 2 process and an Al.sub.2O.sub.3 particle size distribution (b) generated by an EPMA; and

0060] FI

Problems solved by technology

The compositions as well as the particle sizes of the compositions and the particle size distribution of these intermetallic inclusions seriously affect the quality of the steel material, particularly the pureness of roller bearings when the steel material is used as a material for the roller bearings.

For example, when a steel material for roller bearings contains a large number of intermetallic inclusions having relatively large particle sizes of more than 3 .mu.m, peeling or the like easily occurs at these intermetallic inclusions, which results in considerable deterioration in the pureness of products, such as roller bearings.

However, the method using an EPMA requires a complicated procedure including operations of electronic probing and various arithmetic operations, and hence this method cannot speedily determine the composition and particle size distribution of each of intermetallic inclusions contained in a large amount of samples cut out from steel materials.

The extrapolation makes it difficult for the disclosed method to correctly determine the particle sizes and the particle size distribution.

However, when it is necessary to obtain an Al calibration curve, since the background of the Al-based alloy is not iron (Fe), it is difficult to accurately determine Al contained in the intermetallic inclusions existing in the steel.

Moreover, due to existence of a high emission spectrum intensity of an element, such as Mg, whose emission wavelength is close to that of Al, it is difficult to correctly identify the concentration of Al.

Since the correlation between the average particle size thus estimated to be smaller and the real particle size cannot be clearly determined, the relationship between the average particle size estimated to be smaller and the rolling life may not be accurately determined.

However, it is difficult to carry out these methods conveniently, since the electron beam elution method necessitates an apparatus for performing the same method, and / or it takes time to effect the elution or extraction.

Images