The Effect of Graphite Morphology on the Propagation of Ultrasonic Wave in Ductile Cast Iron

구상흑연주철에서 초음파 전파속도에 미치는 흑연형상의 영향

  • Lee, Kye-Wan (Department of Metallurgical Engineering, Hanyang University) ;
  • Yang, No-Seok (Department of Metallurgical Engineering, Hanyang University) ;
  • Park, Un-Su (Department of Metallurgical Engineering, Hanyang University)
  • 이계완 (한양대학교 공과대학 금속공학과) ;
  • 양노석 (한양대학교 대학원 금속공학과) ;
  • 박온수 (한양대학교 대학원 금속공학과)
  • Published : 1989.06.20


The relationships between nodularity, tensile property and ultrasonic velocity were studied in ductile iron castings having similar matrix structure. Also, the effects of heat treatment and the number of graphite nodules on the ultrasonic velocity were investigated. The results were as follows 1. The ultrasonic velocity increased proportionally with increassing nodularity and tensile strength. 2. The ultrasonic velocity in annealed and normalized state decreased average 1.7% and 3.4% respectively than that in as cast state. 3. The ultrasonic velocity increased with increasing the number of graphite nodules. Therefore, ductile iron castings can be evaluated in the only case of castings having the same manufacturing history by ultrasonic velocity.