Residual stress measurement in carbonitrided shot-peened steel using the incremental groove machining coupled with speckle pa

Author:  Van Wijk, Francois, Frabolot, Sura, Ghodhbani
Source:  Conf Proc 2011: ICSP-11 South Bend, IN USA (pgs. 153-158)
Doc ID:  2011025
Year of Publication:  2011
Abstract:  
Abstract Shot peening is a commonly used surface treatment to introduce compressive residual stress in carbonitrided gears. An effective measurement of stress gradient is an important factor in order to bring a better comprehension of shot peening mechanisms and to assess fatigue and wear properties of gears. Electronic Speckle Pattern Interferometry (ESPI or DSPI) is a technique which allows to determine the displacement field of a deformed object with high resolution. The aim of this work is to quantify residual stress in carbonitrided and shot peened steel using an innovative method combining ESPI with incremental groove machining. ESPI is used to measure, with submicrometer resolution, the displacement field due to local stress relaxation occurring after machining a groove of a few micrometers depth. To obtain the complete stress profile, further machining increments are performed with ESPI measurement between each. To obtain the relation between measured displacements and the residual stress inside the groove, a finite elements model is developed to calculate the matrix of calibration coefficients for each depth. The reliability of this technology is also tested in this work by comparing the residual stresses determined by ESPI with those measured by X ray diffraction method. Keywords Residual stress, Electronic speckle pattern interferometry (ESPI, DSPI), Simulation, Shot peening, carbonitriding.