Evaluation and Control of Residual Stress Measurement Using Stress Standard Specimen

Author:  Dr. Yuji Kobayashi, Sintokogio
Source:  The Shot Peener magazine, Vol 33, Issue 3, Summer 2019
Doc ID:  2019028
Year of Publication:  2019
Abstract:  
Introduction: Shot peening is a processing method in which particles of small size called media (shot) are made to impact the surface of a workpiece. It is often used on components such as gears and springs to improve fatigue strength. Residual stress is one of the parameters which represents the effect of shot peening. It helps prevent crack propagation. Residual stress can be measured by an X-ray diffraction method. A commonly used technique is the sin2 ψ method (with 0-dimensional or 1-dimensional detector). On the other hand, a method using an image plate (two-dimensional detector) has recently been put to practical use. It is called the cosα method (Figure 1). This method reduces the size of the measuring device and reduces the measurement time in comparison to the conventional sin2 ψ method.