No abstract

The distribution of residual stresses was determined in an overlay dissimilar joining pipe weld using neutron diffraction. The specimen was dissimilarly welded between the bcc ferrite steel (SA508) and fcc austenite (SA182) steel with the Ni-based welding consumable (Alloy 182). The weld pipe simulates the nozzle joint component of the nuclear power plants with the dimension of about 130-mm diameter, 500-mm length, and 21-mm thickness. A total of 13 positions were measured from 2 mm to 20 mm underneath the pipe outer wall with 1∼2 mm steps along the weld centerline. The neutron beam gauge volume provides 1-mm spatial resolution along the thickness direction of the weld pipe. The macroscopic ‘stress-free’ lattice spacing (do) was also measured using 2-mm width comb teeth coupons taken from the identical location of the bulk weld neutron-diffraction measurements. The result shows that the hoop stress component developed tension of about 100 MPa and compression of −600 MPa near the outer and inner wall surface of the overlay pipe weld, respectively.