Method and Apparatus for Peening the Internal Surface of a Non-Ferromagnetic Hollow Part

Author:  KM Prewo, P Sainz de Baranda, VC Nardone, Connecti
Source:  US Patent 5,950,470
Doc ID:  1999073
Year of Publication:  1999
Abstract:  
The present invention is a method and apparatus for peening the internal surface of non-ferromagnetic hollow parts. Ferromagnetic peening elements are inserted into the non-ferromagnetic hollow part, and a magnetic dipole creates a magnetic field through the non-ferromagnetic hollow part attracting the peening elements which contact a portion of the internal surface of the non-ferromagnetic hollow part. The magnetic field is disengaged and a second magnetic dipole creates a second magnetic field, thereby causing the peening elements to contact a second portion of the internal surface. The magnetic dipoles are repeatedly turned on and off, thereby causing repeated impact within the interior of the hollow part until the internal surface attains a predetermined stress level.