Aluminum melts degassing by ultrasonic irradiation
A series of factors that affect porosity formation in ingots during ultrasonic irradiation was studied, including ultrasonic power, ultrasonic duration, pre-degassing and ultrasonic resonance. Ultrasonic degassing (USD) mechanisms were analyzed. Finally, a method which combined ultrasound and forced cooling at the bottom of the ingot was used to prevent the porosity formation during solidification. The results indicate that ultrasonic power must exceed a certain threshold to eliminate porosity in ingots, and that sufficient ultrasound duration is also required. Compared with conventional treatment methods, which use large amounts of hexachloroethane (C2CI6) to degas the melt, ultrasound alone is effective for degassing under the condition of ultrasonic resonance. The degassing effect arises from cavitation produced in the melt. The cavitation effect is divided into two regimes, depending on its intensity. If the intensity is less than a certain value, sub-cavitation occurs and there is no degassing effect. If the intensity is greater than this value, developed cavitation occurs, resulting in highly effective degassing. By combining ultrasound and forced cooling at the bottom of the ingot, the porosity content of ingots can be significantly reduced. This method can reduce porosity to 0.02x10-5 m3/kg (0.02 cc/100 g), which is less than the minimum content of 0.1 ×0-5 m3/kg (0.1 cc/100 g) required by commercial processes. The degassing efficiency can reach 97％, proving that combining ultrasound with forced cooling at the bottom of the ingot is a practical, rapid and highly effective degassing method. The degassing efficiency obtained by this method is higher than that obtained by vacuum melt irradiation methods or the GBF method using blown argon gas. The method shows good potential for development.
ultrasonic irradiation (UI) porosity formation aluminum melt ingot prevention
Junwen Li Tadashi MOMONO
School of Mechanical Engineering, Jiangnan University, Wuxi 214122, China Department of Materials Sc Department of Materials Science and Engineering, Mururan Institute of Technology, Muroran 050-8585,
国际会议
The 11th Asian Foundry Congress(第11届亚洲铸造会议 AFC-11)
广州
英文
1-5
2011-11-12（万方平台首次上网日期，不代表论文的发表时间）