Application of the Keyhole TIG Process for High Productivity Welding of Superduplex Stainless Steel

Abstract

The paper presents an attempt to use an innovative mechanized K-TIG welding method (a variant of the TIG method) for single-pass welding of superduplex stainless steel without bevelling the edges and without adding a filler metal. The TIG method combines a number of advantages, but the disadvantage is certainly the long and manual welding process. Despite the undisputed high quality of the welded joints, this method is associated with low productivity, deformations and a strong dependence of the final effect on the welder’s skills. The paper describes the design and mode of operation of a fully mechanized welding station for the K-TIG process (which is a complex mechatronic system), the use of which eliminates the disadvantages of the TIG process while maintaining all of its advantages. The characteristics of the duplex steel, as well as the aspects and limitations related to its weldability are also presented. Welding tests were carried out and the test results obtained met the standards based requirements for qualifying the welding procedure and for its practical use in industrial manufacturing. As part of the paper, a comparative analysis of welding productivity was also carried out by determining the productivity and welding time for the TIG and K-TIG methods in similar process conditions.