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Materials used for high temperature applications are subjected to
various types of degradation phenomenon such as high temperature
corrosion, erosion-corrosion, overheating, solid particle abrasion,
wear, etc. Boiler tubes used for super-heaters and re-heaters in
steam-generating systems are subjected to erosion-corrosion at high
temperature, resulting in tube wall thinning and premature failure.
The present study investigates the high temperature
erosion-corrosion resistance of D-gun sprayed coatings on
"ASTM-SA210-GradeA1" boiler tube steel in actual industrial
environment. SEM/EDAX, XRD and X-ray mapping analysis is done to
reveal the microstructural and compositional features of coated
boiler tube steel. The deposited coatings on Grade A1 steel exhibit
uniform and dense microstructure. Thermogravimetric technique is
used to investigate the erosion-corrosion behavior of uncoated and
coated boiler tube steel at high temperature for 1000 hours.
SEM/EDAX, XRD and X-ray mapping techniques were used to analyse the
corrosion products.
Structural materials in many front-line high technology areas have
to operate under extreme conditions of temperature, pressure and
corrosive environment. So, Materials degradation at high
temperatures is a serious problem in several high tech industries.
Gas turbines in aircraft, fossil fueled power plants, refineries,
and petrochemical industries, and heating elements for high
temperature furnaces are some examples where corrosion limits their
use or reduces their life, considerably affecting the efficiency.
Corrosion causes plant shut downs, waste of valuable resources,
loss or contamination of products, reduction in efficiency and
costly maintenance in the present work, it was planned to study the
behavior of boiler steels subjected to high temperature corrosion
in boiler of thermal power plant. Selection of candidate material
for the study was made after consultation with Guru Nanak Dev
Thermal Plant, Bathinda (India). Thermogravimetric studies were
done to understand the corrosion kinetics. Standard techniques such
as Scanning Electron Microscope (SEM), Energy Dispersive X - Ray
Analysis (EDAX) and X - Ray Diffractometer (XRD) were used to
characterize the corrosion products.
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Wear Behavior (Paperback)
Vikas Chawla, Jwala Parshad Singla, J.S. Grewal
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R1,284
Discovery Miles 12 840
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Ships in 10 - 15 working days
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Wear problem of grey cast irons selected as case study in this work
is being faced in Brake Rotors, where abrasive and adhesive wear of
these grey cast irons takes place due to the abrasive action.
Although efforts have been made to reduce the friction coefficient
and to increase the wear resistance of grey cast irons by varying
alloying elements such as titanium yet there is little or no work
on the use of coatings on various grades of grey cast irons used in
braking rotors. The objective of the study is to develop the
Detonation Sprayed wear resistant coatings Cylindrical pins of grey
iron (GIHC and GI250) have been prepared. Three different coatings
i.e. Stellite-21, Cr3C-25NiCr, and Al2O3-40TiO2 were deposited on
end faces of these pins. Coatings were characterized using SEM/EDAX
and XRD analysis. The wear testing on the uncoated as well as
coated grey cast iron specimens was done with the help of Pin-on-
Disk wear test rig. Wear data was collected for three loads i.e.
40N, 50N, 60N. The worn out specimens were characterized by SEM /
EDXA analyses.
Hardfacing by welding is the most economic way to enhance the life
of the components which are exposed to high abrasion environment.
Chromium rich electrodes are widely used due to their low cost. It
is planned to study the effect of carbon and chromium over a wide
range, on the resultant microstructure as well as wear behavior of
the deposited layers, of the bottom plate of concrete mixer used in
ready mix concrete plant.Six types of iron-based hardfacing
electrodes with a wide range of C (0.6-5% by wt.) and Cr (3.5-35%
by wt.) were selected to deposit, by the manual metal arc welding
process on the mild steel plate of concrete mixer. The abrasive
wear responses, hardness and the microstructures were compared with
that of mild steel.Abrasion tests were carried out in a sliding
wear abrasion test machine. surface analysis were made using
SEM-EDAX, XRD Analysis.Field test was performed, by hardfacing on
the actual size mild steel plate.The extent of improvement in wear
performance of mild steel due to all hardfacing alloys is quite
appreciable as compared to mild steel. Further the life of
hardfaced plate was enhanced by 3.11 times compared to mild steel
plate resulting net cost
it is now generally accepted practice to apply coatings to
components in fossil fuel energy processes to protect against
surface degradation processes such as wear, oxidation, corrosion
and erosion.The nanostructured thin TiAlN and AlCrN coatings
deposited by PVD technique and the conventional thick TiAl and AlCr
coatings deposited by Plasma Spraying and further gas nitrided;
were selected for the present work. After conducting the various
experiments on uncoated and coated alloys (total 16
substrate-coating combinations along with the bare alloys) in lab
and in actual industrial environment which includes the
characterization of the nanostructured and conventional TiAlN and
AlCrN coatings on selected Fe-based alloys and their behavior when
exposed to high temperature oxidation studies in air, molten salt
environment and in a coal fired boiler of a thermal power plant,
erosion studies in simulated coal-fired boiler environment; the
coating-substrate combinations which are found successful in
protecting the substrates from oxidation, hot corrosion, erosion
and wear are proposed to provide thermal insulation, corrosion and
wear resistance to the components in chemical process plants
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