Measurements of residual strains in a shape welded steel tube by neutron and x-ray diffraction methods

Shape welding of a ferritic steel layer on an austenitic steel tube is used to build compressive stresses on its outer surface as a result, suppress stress corrosion. Investigations of residual stresses in such bi-layer tubes are important for developing of optimal welding techniques. The neutron and X-ray diffraction methods were used to analyze the stress behaviour around the welded region on the tube. To this end, strain components in the radial, axial and tangential directions were measured across the weld. The results are compared to the data obtained by the destructive turning out technique and theoretical predictions by the finite element method