《NARROW_GAP_WELDING_EN》.pdf

NARROW GAP WELDING OF HEAVY WALL THICKNESS MATERIALS IN NUCLEAR AND FOSSIL FUEL INDUSTRIES THE DIFFERENT VARIANTS: ADVANTAGES AND LIMITATIONS INDICATED BY EXAMPLES Introduction TIG welding of heavy wall thickness materials in an orbital configuration, or prefabricated on rotating work pieces is ever more common despite the many alternative technologies. This process has proven that once all the constraints have been taken into account; TIG welding remains the best process for dealing with the many inconsistencies that have to be incorporated to make automation successful. POLYSOUDE has paid close attention to the various manufacturing conditions which, due to their complexity, require a specific solution almost every time. It brings accommodation of the technical procedure and the welding equipment to reach the most apposite compromise. The Determining Variables The approach to setting up a Narrow Gap welding procedure specification requires precise analysis of certain essential variables. These variables will be the main factor in determining whether or not it is truly possible to perform Narrow Gap welding within the financial or technical constraints of the project environment, especially in the nuclear industry. Let us review the main points and associated considerations.  Dimensional characteristics of the workpieces Of course, this is fundamental key as the relevance will increase as the thickness increases. Consideration must be given to the fact that the Narrow Gap technique is trickier to develop and will only be of benefit and be cost-effective when the thickness is consistent. As a general rule, Narrow Gap welding will not be cost-effective or technically efficient for thicknesses of less than 25 mm. For thicknesses of 60 mm and above, optimisation of welding time may achieve a factor of between 5 and 10 in relation to conventional TIG welding. This takes into account the combined effect of the reducti