Project Code: 0902-13
The aim of this work is to demonstrate the capabilities of advanced metallographic techniques for distinguishing between girth welds which perform differently in SSC testing.
Test material, comprising sections from two similar welds, one of which has passed four point bend SSC tests, and the other of which has failed, is available. The examination will be based around Electron Back Scattered Diffraction (EBSS) and Scanning Transmission Electron Microscopy (STEM) in the TWI high resolution FEG SEM. The work will be exploratory in nature, and will aim to discover if differences can be found in texture, microphases, residual strain (from steel/pipe manufacture), using EBSD and precipitates in the steel using extraction replicas and STEM. In the example material, a feature of the unexpected failures has been cracking in parent material, and therefore work will start with examinations of parent materials. The work will involve a degree of development of techniques (in particular for EBSD analysis of steels).
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