An experimental analysis of temperature and stress fields in girth welded 304L stainless steel pipes
- Oregon Graduate Inst. of Science and Technology, Portland, OR (United States)
- Oak Ridge National Lab., TN (United States)
The thermal and deformation/strain histories were measured by a computer data acquisition system for three 406-mm-diameter, Type 304L stainless steel (SS), schedule 40 (12.7 mm thickness) pipe girth welds. Two welds were standard V groove preparations and completed in six and nine (discontinuous) passes with multiple start-stop positions, while the third one was a narrow groove configuration and finished with four continuous passes with one start-stop position. The thermomechanical history measurements were taken on the pipe inner surface, encompassing the weld centerline (WCL) and heat-affected zone; a total of 47 data acquisition instruments were used for each weld to monitor weld shrinkages, surface temperatures, surface strains, and radial deformations. The experimental data give the following general conclusions: (1) the temperature profiles in the two V groove weldments are, in general, axisymmetric, while the temperature profile in the narrow gap groove weldment is axisymmetric in locations far from WCL, but is not axisymmetric in locations near start-stop position; (2) the strain/deformation histories are controlled by the thermal histories with the final strain/deformation value largely determined by the last one or two passes of welding; (3) the strain/deformation profile in the weldment is not axisymmetric suggesting that the residual stress is not axisymmetrically distributed; (4) the four-pass narrow gap weldment experienced the fewest time and temperature cycles during welding, and has the lowest level of radial deformation among the three pipe weldments indicating that the narrow gap weldment would have the lowest overall residual stress level among the three pipe weldments. Residual stress measurements on the inner surface of four-pass pipe weldment were performed using the neutron diffraction (ND) technique. The ND results show that a tensile zone exists on the pipe inner surface and in the weld and its heat-affected zone (HAZ) area.
- OSTI ID:
- 442927
- Report Number(s):
- CONF-950682--; ISBN 0-87170-567-2
- Country of Publication:
- United States
- Language:
- English
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