Variability of a Shot Stream's Measured Peening Intensity

摘要

A particular shot stream should always be regarded as a combination of shot particles carried along in a stream of fluid. The fluid is normally air but is sometimes water and could, conceivably, be any one of many other fluids. Shot streams differ from one another in terms of their average peening intensity. The principal causes of this difference are generally well-understood being: shot size, velocity and density. An independent increase in any one of those parameters will increase the average peening intensity. The measured peening intensity for one particular shot stream is not, however, constant - it is a variable quantity whose variability is less well-understood. This variability of peening intensity - as derived from a saturation curve - depends on three factors: position, angle and time. A useful acronym to bear in mind is "PAT", with the P standing for Position, A for Angle and T for Time. Shot peening requires strict control of each shot stream's peening intensity. This article therefore attempts to explain how and why the peening intensity of a particular shot stream varies.