Introduction: Basic classification of welding processes, weldability, weld thermal cycle, metallurgy
of fusion welds, solidification mechanism and microstructural products in weld metal, epitaxial,
cellular and dendritic solidification, metallurgical changes in weld metal, phase transformation
during cooling of weld metal in carbon and low alloy steel, prediction of microstructures and
properties of weld metal. Heat affected zone, re-crystallization and grain growth of HAZ, gas metal
reaction, effects of alloying elements on welding of ferrous metals. (6 Hours)
Welding Arc: Arc efficiency, temperature distribution in the arc; arc forces, arc blow, electrical
characteristics of an arc, mechanism of arc initiation and maintenance, role of electrode polarity on
arc behaviour and arc stability, analysis of the arc. (5 Hours)
Coated Electrodes: Electrode coatings, classification of coatings of electrodes for SMAW, SAW
fluxes, role of flux ingradients and shielding gases, classification of solid and flux code wires,
(5 Hours)
Fusion Welding reviews: Critical reviews of manual metal arc welding (MMAW) GTAW, GMAW,
FCAW and CO welding processes, plasma arc, submerged arc welding, electro gas and electro slag
welding, analysis of the process. (5 Hours)
Welding power sources: Arc welding power sources basic charters tics of power sources for various
arc welding processes, duty cycles, AC, DC welding power source, DC rectifiers, thyristor controlled
rectifiers, transistorised units, inverter systems. Arc length regulation in mechanised welding
processes, (5 Hours)
Metal Transfer and Melting Rate: Mechanism and types of metal transfer, forces affecting metal
transfer, modes of metal transfer, metal transfer in various welding processes, effective of polarity on
metal transfer and melting rate. (5 Hours)
Solid State welding: Theory and mechanism of solid sate welding. Techniques and scope of friction
welding, diffusion welding, cold pressure welding and ultrasonic welding. High energy rate welding.
Analysis of the Process. (5 Hours)
Welding Techniques using Radiation energy: Technique, scope and application of the electron beam
and laser welding processes.