IIT (ISM) researchers develop innovative technique for joining of dissimilar metals

Dhanbad: The complicated process of Joining of dissimilar metals, which offered a challenge for many industries, including, Aerospace, Automotive, Electronic, Medical, Ship Building, Defence and Power Generation industries has been solved by a group of IIT (ISM) researchers by devising an innovative technique of joining of metals.

The complexity associated with the joining of dissimilar material is primarily due to difference in their physical and chemical properties as well as different chemical composition.

The Traditional method of welding of 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.

Taking up the challenge to solve the problem associated with welding process of dissimilar metals, a group of three researchers of IIT (ISM) led by Nirmal Kumar Singh, Associate Professor of Mechanical Engineering

Department, have carried out four year research between 2017 to 2021 to ensure Joining of dissimilar materials like Inconel 625 and DSS 2205 through Laser Beam Welding process.

The welds produced through Laser Welding Process have fine heat affected zone, lower brittle inter-metallic phase formation and lower power consumption than conventional arc welding process.

Furnishing details about the project, Professor Singh said, “We carried out the study as part of a project IIT (ISM), titled— “Investigating the effects of Process parameter on weld pool thermal history and mechanical properties of Laser Welded Inconel 625 and Duplex Stainless Steel 2205 dissimilar welds.”

Divulging more details, Professor Singh who carried out the project with the help of Senior Research Fellow (SRF), Gulshad Nawaz Ahmad and Mechanical Engineering Department of IIT (ISM) and another SRF of IIT Kharagpur, Md Shahid Raja said, “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 as part of our project”

“The welded material generated through the laser beam welding of Inconel 625 and DSS 2205 has excellent characteristics like narrow weld bead, low distortions, low residual stress, high productivity and short cycle time and productivity” claimed Professor Singh.

Elaborating about the Laser Beam Welding (LBW) technique used by the IIT (ISM) researchers to achieve welding of dissimilar materials like Inconel 625 and DSS 2205, Professor Singh said, “LBW has received increased attention during the recent years for joining of dissimilar materials due to several advantages like high power densities and welding speeds resulting in rapid heating and cooling, refining microstructure and reducing the formation of brittle intermetallic phases or Laves Phases.

He further said that Fiber Laser Beam Welding is carried out under controlled condition to avoid health hazard and safety problem due to laser radiation emanating from the equipment.

“Appropriate health and safety precautions are strictly followed during the welding process,” added Singh.

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