Analysis for Non-Metal Inclusions and Precipitates Leading to the Optimal Steel-Properties and Processes

Metallic materials as represented by steels mostly contain various precipitates such as nitrides, carbides and inter-metallic compounds in addition to non-metallic inclusions, oxides and sulfides. These are present as an inevitable former or by design. Those varieties, size and distribution types are very wide then one of important structural factors that affects on various properties of materials.Therefore, accurate analysis of them is considerable significance to control target properties of materials reproducibly. In the steel research field, study of analytical methods for inclusion in steels has been actively conducting since 1960’s. Especially in chemical analysis method, systematization and standardization like JIS has been promoted by corroborated researches in an ISIJ. Previously established methods and detail of analysis of chemical states have been described in publications edited by ISIJ and comprehensive review paper has been issued by Takayama. In this short article, direct observation methods with microscopy, rapid analysis categorized as instrumental analyses, non-destructive inspections and extraction method for non-metallic inclusions are briefly reviewed.