An Automated X-Ray Stress Measurement System Using a Microcomputer

An automated system for a rapid and precise X-ray stress measurement using a microcomputer has been developed. A block diagram of the system and a flowchart for the stress measurement method are shown. Of the various methods, the one most suitable for the material to be measured can be programmed in this system. The residual stress in a hardened steel having a broad diffraction profile (half-width of 7.2°) could be measured in six minutes with a small standard deviation of 13 MPa by the Gaussian curve method using the sin2ψ method. Both the oscillation and the fixed ψ methods, using the Gaussian curve method, allow the X-ray stress measurement of coarse-grained steels; the sin2ψdiagram obtained by these methods had a good linearity. The residual stress measurement of an annealed chromium powder gave almost zero stress values, -3.2 to 2.9 MPa depending on the method used, showing high accuracy of the system.