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The technical
expertise and knowledge base of the institute has been fully applied to
benefit to a wide range of industries through in-house and industry
referred projects. Some of the major developments are listed below.
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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.
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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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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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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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A non-
contact type sensor based seam tracker for arc welding applications
has been developed to facilitate automation and mechanization in
welding. This system is suitable for fillet and butt welding
applications as well as for circumferential and long seam welding
for pressure vessels. The sensing system is based on inductive
method and the sensors are capable of operating upto 600ºC and
hence can be used for seam tracking with preheated plates. |
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Over the
years a number of special purpose in-situ polishing devices such as
Controlled Electro Polisher In-situ (CEPIN), All Position In-situ
Electro polisher (APINE) and Versatile All position In-situ Electro
polisher (VAPINE) have been developed to enable metallographic
polishing in difficult location. With these techniques it is also
possible to carry out high quality replication even on warm
components. |
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