Two Strip Setting-Up and Verification Program for Peening Intensity
Author: Dr. David Kirk | Coventry University
Source: The Shot Peener magazine, Vol 39, Issue 1, Winter 2025
Doc ID: 2025006
Year of Publication: 2025
Abstract:
INTRODUCTION
The most accurate method of estimating peening intensity is
to produce and analyze a saturation curve constructed from
the arc heights of four (or preferably more) peened Almen
strips. There are, however, situations where it is expedient
to employ a quicker, albeit less accurate, method. These
include when a new set-up is being developed and when an
established set-up has to be periodically verified. This article
presents a simple computer program that optimizes two-strip
setting-up and verification testing.
Fig.1 shows the basic features of peening intensity
estimation based on the arc heights of four Almen strips
peened for different time periods. These time periods can be
actual times but are commonly integral numbers of passes or
strokes of the shot stream over the Almen strip. The peening
intensity is preferably estimated as the unique ‘time’ for
which doubling that time produces a precise 10% increase in
arc height. That unique time, T, will rarely coincide with an
integral number of passes. Moreover, each strip’s arc height
falls somewhere within an error band. Computer programs,
such as the Solver suite, easily and objectively derive the
unique peening intensity, H, that occurs at the defined time,
T. The required objective is that H shall lie between userdefined
upper and lower values.
A feature of saturation curves is that, for a steady shot
stream, they all have a characteristic shape. This shape
corresponds to a mathematical equation. The set of data
points (arc height versus peening time) can be computer
fitted to a known mathematical equation.
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