In-Situ Stress Measurement with the Canmet Portable X-Ray Stress Diffractometer
A new instalment has been developed to measure in-situ residual or applied stresses by X-ray diffraction. The instrument has the capability to conpensate for texture gradients or coarse grain size, to operate in both single- and multiple exposure modes, to determine surface stress tensors without repositioning and to examine diffraction lines wider than the detector aperture. Laboratory tests on ferritic steels show the instrument to be capable of a standard deviation of 14.6 MPa in the single exposure mode and 5.8 MPa in the multiple exposure mode. The diffractometer was used to measure stress near welds in the Deaerator Storage Tank in Ontario Hydro’s Lakeview Thermal Generating Station (T.G.S.) — Unit #7 at Mississauga, Ontario. Large compressive residual stresses were found parallel and perpendicular to the welds by single- and multiple exposure techniques.
KeywordsBragg Reflection Ferritic Steel Texture Gradient Grit Blasting Stress Corrosion Cracking
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