Welding Processes

By Prof. Murugaiyan Amirthalingam   |   IIT Madras
Learners enrolled: 726

The modern material assemblies require the combined use of alloys for a given commercial application. Welding technologies are of critical importance for the construction of virtually all components of the assemblies. This course aims to elaborate the physical principles of arc, plasma, laser, resistance spot, electron beam and solid state welding processes. This includes, physics of electric arc-plasma, engineering the arc-plasma for welding, metal transfer and mass flow in the weld pool, laser/electron beam - material interactions, pressure and force balance in keyhole mode power beam welding, fundamentals of heat generation by Joule heating and process principles and overview on types of resistance and solid state welding processes. 

INTENDED AUDIENCE : Masters students in Metallurgical, Mechanical, Automobile and Production Engineering. Practicing welding engineers, welders, R&D personnel in academia and national laboratories, quality management personnel from welding and manufacturing industries and research scholars who are working in welding and joining.

PREREQUISITES : Graduates of Metallurgical/Mechanical/Automobile/Production Engineering

INDUSTRY SUPPORT : Construction, Fabrication, Automobile and Power generation industries and research labs

Course Status : Completed
Course Type : Elective
Duration : 12 weeks
Category :
  • Metallurgy and Material science & Mining Engineering
  • Materials Joining
  • Minor in Metallurgy
Credit Points : 3
Level : Undergraduate/Postgraduate
Start Date : 23 Jan 2023
End Date : 14 Apr 2023
Enrollment Ends : 06 Feb 2023
Exam Registration Ends : 17 Mar 2023
Exam Date : 29 Apr 2023 IST

Note: This exam date is subjected to change based on seat availability. You can check final exam date on your hall ticket.

Page Visits

Course layout

Week 1  :  Introduction to the course, learning outcomes, general survey and classification of welding processes, Conventional fusion welding processes, Principal heat sources
Week 2  :  Physics of welding arc – Part IGeneral characteristics of an arc, ionisation, dissociation, arc column, anode and cathode fall zones.
Week 3  :  Physics of welding arc – Part IIElectrical conductivity of the arc, heat transfer inside the arc and arc ignition.
Week 4  :  Introduction to arc welding processes – Part I Principles of gas tungsten arc welding, plasma arc welding, advances in gas tungsten arc welding 
Week 5  :  Electrical power sources for welding - General characteristics, conventional and electronic power regulator systems - Tapped transformers, Moving-iron control, Variable inductor, Magnetic amplifier, SCR phase control, Transistor series regulator, Secondary switched transistor power supplies, Primary rectifier-inverter, hybrid designs and microprocessor controlled power sources.
Week 6  :  Introduction to arc welding processes – Part II Gas metal arc, shielded metal arc, flux cored arc, submerged arc welding -consideration of shielding gases, electrode polarity, current setting, types of metal transfer, process efficiency, melting rate, spatter losses and influence of external magnetic field on arc stability and Advanced GMAW processes. Electrode coverings and their functions, types of fluxes, 
Week 7  :  Fundamentals of resistance welding – Part IProcess principles and overview on types of processes (spot, projection, butt, seam, and flash) Joule effect and temperature distribution. 
Week 8  :  Fundamentals of resistance welding – Part IIProcess application range and typical problems (welding thin to thick material, welding of coated/ painted materials, welding dissimilar materials,mass effect, shunt effect, Peltier effect, resistance brazing.
Week 9   : Introduction to power beam welding processesPlasma, laser and electron beam welding processes - principles and modes of operation, applications and advantages.
Week 10 : Principles of power beam welding processes Keyhole formation, power densities, forces acting in keyhole, pressure balance for a generalised keyhole, heat transfer in laser and electron beam welding processes. 
Week 11 : Introduction to pressure welding processes - solid state bonding, friction welding, friction stir welding, ultrasonic welding, explosive welding, diffusion bonding and adhesive bonding.
Week 12 :  Principles and operational considerations of pressure welding processes

Books and references

Advanced welding processes by John Norrish, ISBN: 978-1-84569-130-1. 
2. Principles of Welding by Robert W. Messler Jr., ISBN: 978-0-471-25376-13. Welding Technology by G. den Ouden and M. Hermans, ISBN: 978-90-6562-205-1. 
4. The Physics of Welding, J.F. Lancaster, ISBN: 0-08-034076. 

Instructor bio

Prof. Murugaiyan Amirthalingam

IIT Madras
Instructor is currently working as an Assistant Professor in IIT-Madras. His research and teaching interests include welding metallurgy, welding processes development, steel product development and additive manufacturing.

Course certificate

The course is free to enroll and learn from. But if you want a certificate, you have to register and write the proctored exam conducted by us in person at any of the designated exam centres.
The exam is optional for a fee of Rs 1000/- (Rupees one thousand only).
Date and Time of Exams: 
29 April 2023 Morning session 9am to 12 noon; Afternoon Session 2pm to 5pm.
Registration url: Announcements will be made when the registration form is open for registrations.
The online registration form has to be filled and the certification exam fee needs to be paid. More details will be made available when the exam registration form is published. If there are any changes, it will be mentioned then.
Please check the form for more details on the cities where the exams will be held, the conditions you agree to when you fill the form etc.


Average assignment score = 25% of average of best 8 assignments out of the total 12 assignments given in the course.
Exam score = 75% of the proctored certification exam score out of 100

Final score = Average assignment score + Exam score

YOU WILL BE ELIGIBLE FOR A CERTIFICATE ONLY IF AVERAGE ASSIGNMENT SCORE >=10/25 AND EXAM SCORE >= 30/75. If one of the 2 criteria is not met, you will not get the certificate even if the Final score >= 40/100.

Certificate will have your name, photograph and the score in the final exam with the breakup.It will have the logos of NPTEL and IIT Madras. It will be e-verifiable at nptel.ac.in/noc.

Only the e-certificate will be made available. Hard copies will not be dispatched.

Once again, thanks for your interest in our online courses and certification. Happy learning.

- NPTEL team

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