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PRCI PR-140-124
- Toughness of Submerged Arc Welds In Pipeline Steels
- Report / Survey by Pipeline Research Council International, 10/01/1981
- Publisher: PRCI
$48.00$95.00
L41002e
Welding Institute of Canada
Need: In recent years, considerable emphasis has been placed on the assessment of the toughness of line pipe steel and on the fitness-for-purpose analysis of girth welds.
The need to provide economic transportation of oil and gas from harsher environments has led to the development of strong, tough line pipe materials. However, although a reasonable amount of data is available on the pipe material, little has been published on the after weld properties.
Result: The object of this study was to assess the properties of a series of line pipe welds produced by several manufacturers. A series of seven line pipe and weld metals have been studied varying in strength level from X60 to X70, in diameter from 26" to 48", and in thickness from 0.375" to 0.720". The weld metals were all made using a two-pass, high-heat-input, submerged-arc weld by either a U and O or spiral technique. The pipes and weld metals were assessed for their microstructural content and tensile strength, and Charpy impact energies and crack tip opening displacements were measured in the pipe, heat-affected zone and weld metal at room temperature and at -45oC.
Benefit: A wide range of properties were observed in the welds, and these could be related to inclusion content and microstructure. The weld metals consisted primarily of true grain boundary and intragranular ferrite. The microstructure could be related to the hardenability of the weld, and the amount of intragranular ferrite increased at the expense of true grain boundary ferrite up to a limit of C.E. = 0.45%, when bainitic ferrite is formed.
Welding Institute of Canada
Need: In recent years, considerable emphasis has been placed on the assessment of the toughness of line pipe steel and on the fitness-for-purpose analysis of girth welds.
The need to provide economic transportation of oil and gas from harsher environments has led to the development of strong, tough line pipe materials. However, although a reasonable amount of data is available on the pipe material, little has been published on the after weld properties.
Result: The object of this study was to assess the properties of a series of line pipe welds produced by several manufacturers. A series of seven line pipe and weld metals have been studied varying in strength level from X60 to X70, in diameter from 26" to 48", and in thickness from 0.375" to 0.720". The weld metals were all made using a two-pass, high-heat-input, submerged-arc weld by either a U and O or spiral technique. The pipes and weld metals were assessed for their microstructural content and tensile strength, and Charpy impact energies and crack tip opening displacements were measured in the pipe, heat-affected zone and weld metal at room temperature and at -45oC.
Benefit: A wide range of properties were observed in the welds, and these could be related to inclusion content and microstructure. The weld metals consisted primarily of true grain boundary and intragranular ferrite. The microstructure could be related to the hardenability of the weld, and the amount of intragranular ferrite increased at the expense of true grain boundary ferrite up to a limit of C.E. = 0.45%, when bainitic ferrite is formed.