THE EFFECTS OF NON-CONTACT ACOUSTIC VIBRATIONS ON THE SOLIDIFICATION AND MICROSTRUCTURE OF DUCTILE AND GRAY CAST IRON
Open Access
- Author:
- Grenko, Timothy Michael
- Graduate Program:
- Industrial Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- None
- Committee Members:
- Robert Carl Voigt, Thesis Advisor/Co-Advisor
- Keywords:
- vibration
ultrasonic treatment
cast iron
solidification - Abstract:
- Numerous research studies have examined the use of vibration to treat solidifying metals. The topic was first investigated by the Russians in the early 1900’s. Early efforts were unsophisticated and poorly documented. The method of rocking molds by hand to create low frequency vibrations was first employed. Since these first experiments were performed, significant advances have been made in equipment and technique. Researchers have pursued the treatment of solidifying metals with vibration for increased fluidity, improved casting yield, and overall casting quality improvements. Energy transmitted through vibration has been found to degas melts, modify final microstructures, and improve mechanical and corrosion properties. Until recently, studies of the application of ultrasonic energy to solidifying metals have been performed almost entirely using methods of contact energy transmission. Contact resonator practices were plagued with problems of melt contamination and chill. Limited study has been aimed at the use of non-contact methods of ultrasonic stimulation of solidifying metals. This thesis investigates the use of non-contact ultrasonic vibration treatment during the solidification of ductile and gray cast iron alloys, which. The solidification behavior of ductile cast iron and gray cast iron was evaluated in the inoculated and uninoculated conditions when subjected to non-contact ultrasonic vibration of various frequencies. Solidification cooling curves and final microstructure of each iron alloy as was examined. Ultrasonically treated ductile iron produced increased graphite nodularity, with a corresponding decrease in graphite nodule size. Inoculated and uninoculated gray cast iron treated with ultrasonic energy realized an increase in flake graphite size. Minor increase in overall solidification time was realized through non-contact ultrasonic vibration.