SUBHASH MISHRA
Dhanbad, Oct 11: A three-member research team of IIT Indian School of Mines (ISM) Dhanbad has developed a new laser beam technique for joining dissimilar metals.
Joining dissimilar materials is considered a complicated process due to differences in their physical and chemical properties as well as different chemical compositions. Many industries such as Aerospace, Automotive, Electronic, Medical, Ship Building, Defence and Power Generation sectors face major challenges in joining dissimilar metals.
The research team under Prof Nirmal Kumar Singh, associate professor of the Mechanical Engineering Department, took up the challenge of welding process of dissimilar metals and in four years (2017 to 2021), developed the device to ensure joining dissimilar materials like Inconel 625 and DSS 2205 through Laser Beam welding process.
Gulshad Nawaz Ahmad, senior research fellow (SRF) of the mechanical engineering department of IIT ISM and Md Shahid Raja (SRF) of IIT Kharagpur were the other members of the team.
Prof Nirmal Kumar Singh while giving details of his research said that Fibre Laser Beam Welding is carried out under controlled conditions to avoid health hazards and safety problems due to laser radiation emanating from the equipment. “Appropriate health and safety precautions are strictly followed during the welding process,” Singh said.
The traditional method of welding dissimilar materials like Metal Inert Gas (MIG) welding, Tungsten Inert Gas (TIG) welding and Shielded Metal Arc welding (SMAW) have their own difficulties and associated complications like Brittle Inter-metallic phase formation, higher distortion of weld bead and large heat affected zone being power consuming.
Researchers claim welding through the Laser Welding process has a fine heat-affected zone, lower brittle inter-metallic phase formation and lower power consumption than the conventional arc welding process.
“Careful selection of welding process is of paramount importance in connection with welding of dissimilar metals. So, welding of Inconel 625 and DSS 2205 which has great use for fabrication of metallic bellows, medical instruments, pressure sensors, turbines discs and blades has been carried out through Laser Beam Welding (LBW) technique,” Md Shahid Raja said,
Elaborating on the Laser Beam Welding (LBW) technique, Prof Singh said, “LBW has received increased attention during the recent years for joining of dissimilar materials due to advantages like high power densities and welding speeds in rapid heating and cooling, refining micro-structure and reducing the formation of brittle inter-metallic phases or Laves phases.
