Non-metallic inclusions have a determining effect on steels behavior and performance. For this reason, its characterization and control assume an increasing importance on the processing of these materials. In this work, the measurements classically adopted, in the past, to control the inclusions are described, highlighting their essentially “reactive” character. The mechanisms through which the inclusions influence steels behavior and performance are briefly reviewed, including the inclusions potential to affect phase transformations.
Once these mechanisms are understood, the evolution of the “pro-active” control measurements adopted during the steel works processing are described, with the purpose to influence the steel inclusion population (characterized by size, distribution, form and chemical composition of such particles). Currently, such measurements are evolving to constitute what has been named “inclusions engineering”: once the most favorable inclusions for a certain product or application are identified, the processing course in steel works is adjusted so they can be obtained. Examples of “inclusions engineering” acts in several kinds of steel are presented and discussed, highlighting the tools employed and indicating the trends for the future of this area, including current limitations on the characterization techniques.
Once the presence of non-metallic inclusions is an inevitable feature of the current steel production processes, one can conclude that the main challenges for the future are (a) on the development of inclusion engineering tools, (b) on the improvement of the inclusions effects understanding, including better knowledge of inclusions properties and (c) on the development of inclusion population characterization techniques, which provide the foreknowledge of the end product's properties. |
