Experimental and numerical thermo-mechanical analysis of welding in a lined pipe

Experimental tests of multi-pass lined pipe welding are reported and a computational procedure for the determination of the history of temperature, strains and residual stresses is presented in this paper and validated against the experimental test results. The lined pipe was manufactured by cooling down the liner made of austenitic stainless steel, AISI304, using liquid Nitrogen, and inserting it inside the backing steel pipe made of carbon-manganese, AISI10305, after the latter was pre-heated in a furnace. The effect of the manufacturing process on the thermo-mechanical analysis has been investigated. A 3-D FE model using ABAQUS has been developed to simulate a circumferential single-pass weld overlay (lap-weld) and two-pass girth welding (butt-weld). Thermal history and strain fields have been recorded during welding using thermocouples and high temperature strain gauges, respectively. Residual stresses have been measured using residual stress gauges, deep-hole drilling technique and the X-ray diffraction technique along the outer and inner surfaces of the lined pipe. The welding test has been repeated twice to assess the accuracy of thermal and mechanical measurements. Overall, very good correlation has been observed between the experimental and numerical results.