Electro-Gas welding process is advantageously employed in many countries for welding of vertical joints in view of the associated overall economy and better mechanical properties of the weld. Typical applications include ship hull structure, pressure vessel, storage tanks, blast furnaces and large steel structures. The institute has developed an automatic Electro Gas Welding machine indigenously.

This machine is capable of welding steel plates upto 50 mm thickness in vertical position upto 4.5 meter height in a single pass. The quantum of weld metal is greatly reduced in this process because the gap between plates can be kept as low as 13-15 mm and the joints do not require post weld Normalising heat-treatment.

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A special purpose cladding system has been developed for internal stelliting of tubes and valves having small diameter bores using MIG welding Process. Salient features of the machine include a special purpose welding torch, a column mounted X-Y slides, a motorized torch holder and synergic MIG welding power source. This system enables mechanised cladding of deep bores with restricted axis in cylindrical sections resulting in excellent weld quality.

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		Low Pressure Plasma Spraying (LPPS) has become a worldwide established process in gas turbine industry for providing MCrAIY type coatings on turbine components for protection against hot gas corrosion and oxidation.
This process is being attempted in other areas also. This technique largely avoids gas-metal reactions even for reactive materials and produces oxide free uncontaminated dense coating having good bond strength. WRI has indigenously developed a LPPS system with rectangular spray chamber (Size 2000x1000x600 mm) for hard facing cylindrical components such as steam turbine spindles and industrial valve components. An innovative high temperature oscillating wear test rig has been indigenously designed to test the functional suitability of LPPS stellited spindles by simulating the actual steam turbine operating conditions in the test rig. The surface finish obtained after coating is harder and smoother than Plasma Transferred Arc (PTA) stelliting. After stelliting only 0.3mm grinding is required.

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This machine has been developed for depositing hard metal layers on worn out coal pulveriser rolls of bowl mills used in Power Plant. This machine employs Submerged arc welding process with specially developed flux cored wire. With necessary attachments, this system can be used for overlaying wear resistant weldmetal on worn out surfaces of similar industrial components. The machine can accommodate jobs upto 1600 mm diameter and weighing upto 3000 Kgs.

An automatic tube butt welder has been developed for joining tubes for high pressure and high quality applications. This machine uses TIG welding process with special controls to programme the parameters for automatic welding. This machine is also capable of MIG welding of tubes and pipes.

A special purpose CO₂ welding equipment was developed for welding of damper flapper blades to join 1.6 mm thick steel sheets to the hub pipe. The main feature of the equipment is the usage of two separate torches which draw power from a single power source.

It is a common knowledge that welding generators consume nearly 30% of the rated power during idle running which is non-productive. An Energy saving device has been developed by WRI to switch off the welding generator if idle running time exceeds a preset time.

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A micro-computer based controller has been developed for sequencing and feed back control for effectively improving the quality of Resistance spot and projection welding.
This controller automatically adjusts the current level against changes in work piece resistance to achieve the desired weld quality and nugget size. Preheat, post heat and multi impulse current programming are also provided. A microprocessor based hand held meter for the measurement of force and current during spot/projection welding has also been developed. A stud welding controller was also developed for machines which are used to fabricate stud welded heat exchanger pipes. The controller is designed to ensure that the welding parameters are always within the range of optimized window which in turn will result assured weld quality.

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Considering the advantages of electronically controlled power sources a transistorized power source of 400A capacity was developed for arc welding applications using MOSFET based secondary chopper. The salient features of this power source include better dynamic response, independent control of arc voltage and current, spatter free CO₂ welding, arc pulsing during MIG welding and easy adaptability for automation.

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