Challenges of measuring residual stresses in large girth welded pipe spools by neutron diffraction

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Date
2016-07-03
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Publisher
Materials Research Forum LLC
Abstract
In this paper, welding induced residual stresses in a welded API 5L X65 girth pipe spools are discussed in as-welded and in local post weld heat treated conditions. Stress measurements were carried out non-destructively using the neutron diffraction technique. For such large-scale components residual stress measurements require significant preparation and planning. First of all, a choice of stress free lattice spacing value, discussed extensively, is of great importance for the evaluation of residual strains and stresses correctly. Besides, the use of a virtual instrument (SSCANSS software) can optimize measurements for distorted or undistorted large components with or without complex details. Moreover, the well-planned “window” cut through the thickness greatly reduced measurement time. A number of points were measured across the weld, HAZ and the parent material. Measurement results showed that residual stresses in the as-welded condition was lower than the yield strength of the material, and significant relaxation was also observed in the post weld heat treated samples. © The Authors
Description
Keywords
Residual stresses, Neutron diffraction, Welding, Pipes, Measuring methods, Heat treatments
Citation
Ren, Y., Paradowska, A., Eren, E., & Wang, B. (2016). Challenges of measuring residual stresses in large girth welded pipe spools by neutron diffraction. Paper presented to the 10th International Conference on Residual Stresses (ICRS 10), Sydney, Australia, 3-7 July, 2016. In T. M. Holden, T. M., O. Muránsky, & L. Edwards (Eds) (2017). Residual stresses ICRS-10. Millersville, USA: Materials Research Proceedings, Vol. 2, 575-580. doi:10.21741/9781945291173-97