Predicting of Shot Velocity in Shot Peening Process

Author:  Guechichi H. and Benkhattab M.
Source:  ICSP-13
Doc ID:  2017087
Year of Publication:  2017
Abstract:  
Introduction: Shot peening is a cold working process in which small spherical parts called shots or peening media are blasted on a surface of a metal work-piece with velocities. Shot peening has wide spread application particularly in the field of the automotive and aerospace industries. The main process parameters which influence the characteristics of the surfaces and surface layers are : machine type, nozzle geometry (spread, diameter), mass flow, shot type (material, form), peening angle,peening time, shot velocity, mechanical properties and the geometrical shape of work material. The velocity of the shots is a significant parameter of shot peening process but it is not used as a controlled parameter by the shot peening industry. Shot velocity is one of the most important parameter of the shot peening process because it governs the kinetic energy of the impacting shot and hence the peening intensity. The velocity can be changed by regulating the air pressure or, in the case of a wheel, by adjusting its speed until the required Almen intensity and coverage are attained. In the industry the Almen gauge, made from SAE 1070 spring steel, is widely used as a standard measurement device for monitoring the arc height of a strip of material after its exposure to a blast of shot. Almen intensity is employed to ensure the repeatability of the peening process of identical parts. Champaigne [1] presented, in more detail, the calibration of Almen gage; the Almen intensity is determined from the interpretation of an Almen saturation curve. The shot peening intensity curve, which produces the specified intensity, will determine the correct set up of the shot peening machine being used. Shot peening process needs to find the optimal parameters. In practice, the higher Almen Intensity is not necessary to be the adequate parameter for the shot peening process. Though Almen strips are widely used in the industry, very few researches have been conducted on the subject of the shot peening velocity. However, the majority of publications have been experimental in nature. In order to reduce the costly use of Almen strips, it is interesting to correlate Almen intensity to shot velocity. The main aim of this study is to propose a method for prediction of the shot velocity using analytical method. The present paper establishes a framework for predictive modeling of shot velocity.