Patent Number: 6,170,308

Title: Method for peening the internal surface of a hollow part

Abstract: The rate of impact between the peening elements and an internal surface of a hollow part is a function of the vibration frequency, and there is a cut-off frequency at which a hollow part can vibrate and induce repeated impact between its internal surface and the peening elements because the rate of impact becomes erratic and loses its cyclical nature as the vibration frequency deviates from the cut-off frequency. The present invention provides a method for determining the cut-off frequency at which a hollow part can vibrate and maintain the repetitive nature of the impact between its internal surface and the peening elements. Such a method requires a peening element speed limit ratio, which is the ratio of the velocity of the hollow part compared to the velocity of the peening element above which the rate of impact begins to become erratic and lose its cyclical nature. The present invention utilizes the peening element speed limit ratio to determine the frequency at which to vibrate the hollow part when peening its internal surface so as to and maintain repeated impact between it and the peening elements.

Inventors: Veronesi; William A. (Hartford, CT), de Baranda; Pedro Sainz (Farmington, CT), Nardone; Vincent C. (South Windsor, CT), Tolman; Stephen E. (Vernon, CT), Wawrzonek; Paul H. (Bondsville, MA)

Assignee: United Technologies Corporation

International Classification: B24B 31/00 (20060101); B24B 39/00 (20060101); B21D 026/14 (); B24C 001/00 ()

Expiration Date: 01/09/2018