Influence of the Position of the Collimator of an X-Ray Diffractometer on the Value of Measured Residual Stresses

In mechanical engineering, in particular, in the manufacture of parts for gas turbine installations and gas turbine engines with variable geometry compressor and turbine blades, holes in disks, etc. and complex shapes, it is necessary to control the level of residual stresses. When using the X-ray diffractometry method, it is necessary to ensure the position of the diffractometer collimator along the normal to the surface under investigation. For the specified parts, this condition is not always feasible. In this paper, the effect of the position of an X-ray diffractometer collimator relative to the measurement surface on the value of the measured residual stresses is estimated. Flat samples from steel 09G2S and alloy VZhL14 are used. The position of the collimator relative to the plane of the sample is determined by an angle alpha that is varied from 0 degrees to 30 degrees in steps of 5 degrees. As a result of the measurements, the values of the measured residual stresses are compared with their value at 0 degrees and the limiting angles are found, above which there is a substantial distortion of the measurement results.