Ultrasonic assessment of inclusions in steel billets

AbstractAn ultrasonic pulse-echo technique for rating steel cleanness is described and applied to billets of AISI4340 high-strength steel and AISI52100 bearing steel. Instrumentation details are stressed. The ultrasonic ratings of the steels correlated well with results obtained by a quantitative television microscope and with inclusion-sensitive mechanical properties including transverse reduction of area, plane strain fracture toughness, fatigue, and impact strength. In addition, the findings of two round-robin tests run by the American Society for Testing and Materials (ASTM) Task Group on Ultrasonic Inclusion Assessment are discussed. Ultrasonic inclusion rating systems, which are being standardized by ASTM, can inspect a large volume of material in a short time and thus help the attainment of better steel quality.