Studies on Ultrasonic Metal Tube Drawing (2)

概要

論文の詳細を見る
Investigation was made on the effect of ultrasonic vibration obtained when a plug used in plug drawing fabrication of tubes is vibrated at a frequency of about 20kHz and the maximum amplitude of 12μm. The plug vibrating system described in the first report was employed also in the present investigation. In a usual drawing fabrication, a metallic soap is applied onto the phosphate film, and the tube is drawn after drying. The plug was subjected to ultrasonic vibration in this state. As a result, the plug force was reduced by about 90%, and the die force, by 10∿30% under appropriate conditions. The results obtained in the case with a relatively small plug force can be explained well by the application of the theory proposed by B. B. Hocaлb. In the drawing with an R type plug, the degree of fabrication by the plug on the inner surface of tube is large, and the plug force is 2∿3 times that with an S type plug. The effect of ultrasonic vibration is accordingly different from that in the S type plug : application of ultrasonic vibration reduced the wall thickness caused by drawing and enabled to obtain tubes of a high fidelity to the tool. To judge from these results, the application of ultrasonic vibration is considered favorable in drawing specials of complicated shapes. The ultrasonic vibration, when applied to a plug, is considered to cause variations in the frictional state between the plug and the blank. In a test carried out with four kinds of lubricant selected, the following two phenomena were observed for lubricants believed to give a thin lubricant film broken by a small breaking pressure. One of these facts is that, in the test with lubricant B, the decrease in plug force is relatively small and that in die force exceeds 50%. Since lubricant B is directly applied to the tube with no preparing solution and dried, the lubricant film is thin as compared to that of lubricant A. A satisfactory acoustic coupling is therefore obtained between the plug and the tube inner surface, thus permitting efficient transfer of ultrasonic vibration to the blank. This transfer is considered to have reduced the frictional resistance of the die surface or the deformation resistance of the matrix and to have largely reduced the die force. The other phenomenon is the chattering preventive effect of ultrasonic vibration. In the cases of liquid lubricants C and D, the lubricant film is weaker, and chattering occurs when a limit is exceeded by the drawing speed. This fact is caused by the interaction between the frictional resistance of plug and blank and the elastic elongation of the mandrel, and consists of repeated sticking and slipping between the blank and the plug. In this state, ultrasonic vibration was applied to the plug. Chattering cannot be eliminated while the vibration speed is still small, but when the vibration speed is raised to about three times that of drawing, chattering can be stopped. These results suggest the existence of an effect of ultrasonic vibration applied to the plug, which breaks up sticking of metal produced on the frictional face between the blank and the plug. Liquid lubricants easy to handle is expected to enable him to reduce the length of lubricating process by the application of ultrasonic vibration. Finally, the observed value of about 1ton of the plug-end driving force in this vibration system, derived from the results of this series of tests, very well agrees with the design value of 1ton. The importance of the focusing method of ultrasonic vibration by the ultrasonic power accumulator in the application of ultrasonic vibration is considered to have been experimentally recognized.
湘南工科大学の論文
1984-03-26

Studies on Ultrasonic Metal Tube Drawing (2)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク