A Digital Evaluation System for Inclusions in Steel

Inclusions in steel materials are generally composed of oxide, silicate from silica, sulfide, and other chemical compounds. These inclusions in steel cause stress concentration on the contact surface between inclusions and steel base, which result in a quenching crack and a decrease of fatigue strength. The inspection of inclusions in steel is high in demand, and is typically carried out manually. This study used a rule-based methodology to develop a division-making architecture for a digital evaluation system. The results from comparison experiments showed that the difference of evaluation grade between digital and manual evaluations was 0.5. Moreover, the time spent on digital evaluation was 30-50 times faster than manual evaluation. In summary, the digital evaluation developed by this study for inclusions is suitable for metallographic inspection.