A-plasma: Use of penetration flux and the plasma process when pipe welding type 316L of thicker dimensions
2004 (English)Conference paper (Refereed)
The maximum penetration depth in inert shielded gas processes as TIG (≤ 3 mm) and keyhole plasma (≤ 8 mm) limit a highly weldable corrosion resistant alloy as the standard austenitic stainless steel 316L to be welded autogenously in dimensions above these maximum penetration depths. Thus an expansion of these penetration ranges would expand the selection of autogenously welded pipes classified by ASTM A312. Also an increase of the productivity rates in pipe welding of thicker dimensions due to less extensively preparations and welding procedures would be a benefit. Using an activated flux to achieve deeper penetration in the TIG process (A-TIG) is today a well-known and established method. In keyhole A-plasma is, however, limited research performed and the use of an activated flux in connection with the partial penetration plasma process is still not evaluated. In the present paper a discussion of different proposed mechanisms affecting the penetration characteristics is made. The experimental procedures when using flux constituents of oxides as SiO2 and TiO2 in connection with the keyhole plasma process and the partial penetration plasma process are also described. A maximum depth in partial penetration A-plasma of 15 mm has been achieved. This is an improvement of 4 times compared with the ordinary partial penetration plasma process. The depth to width ratio became in this case 1.00, which increased the ratio about 7 times. The longitudinal seem welding using two-sided partial penetration A-plasma is limited by the demands of a good groove fitting but a new process for girth welding in thicker dimensions (t ≤ 25 mm) of type 316L is achieved. The keyhole A-plasma process is not recommendable due to the narrow parameter box that changes the non-penetration mode to a cutting mode too abruptly.
Place, publisher, year, edition, pages
2004. 785-791 p.
, Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 2
316L, Activated flux, Girth welding, Penetration depth, Plasma process, 316 L steels, Life-cycle-costing (LCC), Austenite, Carbon steel, Corrosion resistant alloys, Mathematical models, Melting, Pipe, Silica, Steel, Stress corrosion cracking, Surface tension, Titanium dioxide, Plasma welding
IdentifiersURN: urn:nbn:se:kth:diva-157730DOI: 10.1115/OMAE2004-51208ScopusID: 2-s2.0-11244253708OAI: oai:DiVA.org:kth-157730DiVA: diva2:771806
23rd International Conference on Offshore Mechanics and Arctic Engineering, 20 June 2004 through 25 June 2004, Vancouver, BC, Canada
QC 201412152014-12-152014-12-122014-12-15Bibliographically approved