High Density Ceramic Shot for Peening Application

Author:  Julien Cabrero, Benjamin Levy, Renaud Hancy, Anne-Laure Beaudonnet
Source:  ICSP-13
Doc ID:  2017042
Year of Publication:  2017
Abstract:  
Introduction: Ceramic shots are used in a large range of industrial peening applications, such as automotive suspension springs[1], transmission gears[2], aluminium aircraft wheels[3] , titanium turbine engine blades, titanium biomedical implants[4] where significant fatigue strength improvements have been demonstrated. Peening process results are greatly influenced by peening conditions such as media type, velocity, exposure time, but also by the nature and processing history of material workpiece [3]. Recent development to use high performance metallic alloys may require evolutions in peening media design to fully take benefit of peening for lightweighting and optimized functional performance. Ceramic shot features such as hardness, specific gravity, impact strength can be tuned and enhanced up to an unmet level. The aim of the study is to illustrate how the increase of density and hardness of new ceramic shot should open new range of performance for shot peening applications. Ceramic shot, steel shot and rounded steel cut wire were fully characterized (shape, hardness, size, density…). AISI 1070 carbon steel plates were peened under several conditions of pressure in direct pressure cabinet and in wheel turbine equipment. Process parameters such as shot velocity,coverage rate, mass flow rate, and Almen intensity were determined. All those parameters were related to residual stress profile in order to identify the impact of media properties on final results, in comparative conditions. Surfaces were characterized after peening. Finally, media lifetime was measured in some representative conditions.