The welding process of Keyhole Plasma Arc Welding (K-PAW) was employed to weld 6 mm thick. The travel speed of 75mm/min obtained for the perfect weld with Argon gas flow rate of 2.6 ml/min.

The Ultrasonic test results confirmed that a sound weld was obtained for the given parameters without any defects and full penetration was achieved in a single pass. The Microstructural studies revealed the weld consists of two phases ferrite and pearlite are present in the FZ. Yield strength and UTS compared with base metal, K-PAW, GMAW and SMAW joints. Mechanical properties of tests proved that Keyhole plasma weld exhibited good strength and toughness due to the formation of finer grains and narrow heat affected zone.

The joint efficiency for keyhole plasma arc welded joint shown 127% which is higher than the other conventional welding process with ultimate tensile strength of 537 Mpa obtained in the KPAW welded joints.

This article is shared by G. Satheeshkumar, K. Srinivasan, V. Balasubramanian and S. Rajakumar of Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University.