Controlled Rotary Flap Peening for Repair Applications

Author:  S. Forgues, B. Labelle, M. King, N. Manor
Source:  Conf Proc 2011: ICSP-11 South Bend, IN USA (pgs. 1-6)
Doc ID:  2011000
Year of Publication:  2011
Abstract:  
Abstract Shot peening is an important process that improves fatigue life of components without increasing their weight. It is used extensively in the aerospace industry where weight and fatigue are key issues. During the manufacturing and service life of a component, a peened surface might get scratched or slightly damaged. In this case, re-peening is necessary to restore the compressive residual stress layer after removal of the damage area. When re-peening is necessary, rotary flap peening, also known as flapper peening, is often used because it is quick, clean and cost effective. Although the rotary flap peening process has many advantages, it has recently been improved with the introduction of a new controller that continuously monitors and adjusts the rotational speed of the flap. The controller gives the process better repeatability, more visibility and a faster turn-around time. Although the rotary flap peening process has existed for quite some time, very little published data is available on how it compares with conventional peening. The advent of a new controller is a great opportunity to see how rotary flap peening compares to conventional peening in a controlled environment. In this paper, the new controller is used to flapper peen cylindrical fatigue coupons made of 7475-T7351aluminum. Surface roughness, compressive residual stress profiles and fatigue lives are presented and compared with results for conventional peening, using compressed air. Keywords Flapper peening, roto-flap peening, rotary flap peening, 3M, peening repair, portable peening, re-peening, AMS 2590