Quantifying Residual Stress in Shot-Peened Springs

Author:  James Pineault and Mohammed Belassel
Source:  The Shot Peener magazine, Vol 34, Issue 3, Summer 2020
Doc ID:  2020027
Year of Publication:  2020
Abstract:  
RESIDUAL STRESSES in manufactured components, assemblies, and structures can improve or diminish their service life, and this is especially true for coil springs. Because fabrication and forming operations often produce surface conditions that debit the fatigue life of production springs, peening processes are often performed to improve the surface condition and fatigue resistance of coil springs. As there are several different types of coil springs, it follows that each type may experience failure at different locations based on how they are manufactured and used. In compression springs, tensile residual stress at the inner diameter (ID) is the most common source of failure. On the other hand, torsion springs tend to fail at the outer diameter (OD), and tension springs typically fail at the inner radius of their hook. These variation in failure locations make it important to understand the residual stress present in a particular spring before and after shot peening.