Evaluation of low hydrogen welding processes for pipeline construction in high strength steel
Low hydrogen manual welding processes, suitable for pipeline girth welding, have been available for some time for the lower strength pipe grades, and latterly, for high strength pipelines (up to and including X80). Despite their availability and advantages in terms of reduced crack susceptibility, they have been rarely used in production up to the present time. Basic coated shielded metal arc (SMA) electrodes, suitable for vertical-down welding, are produced by some manufacturers at the strength level required for both the root welding and filling of pipeline girth welds. Self-shielded flux-cored wires (SSFCA) are also available for both root and fill welding, and in addition to the low hydrogen levels, these have the advantage of increased productivity. Both of these processes require different methods of deposition compared to welding using cellulosic electrodes, which necessitates specialized training of welders. It is thought that this, along with doubts concerning the reliability and speed of the processes in site conditions, has made contractors reluctant to adopt them. Furthermore, there was a dearth of independently produced information on the welding production performance of low hydrogen processes. Therefore, the primary aim of the present work was to generate data to enable users to make an informed judgment regarding the practical application of low hydrogen processes. Furthermore, it was intended to develop improved root welding procedures, which had been recognized as being significant process limitation. The conclusions and recommendations from this work are discussed.
- Research Organization:
- TWI, Cambridge (United Kingdom)
- Sponsoring Organization:
- American Gas Association, Inc., Arlington, VA (United States)
- OSTI ID:
- 441760
- Report Number(s):
- AGA--97003269
- Country of Publication:
- United States
- Language:
- English
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