The Time-of-Flight Neutron Diffraction Measurements of Residual Stresses in a Shape Welded Steel Tube

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