Effect of Impingement Angle on Erosion Resistance of HVOF Sprayed WC-10Co-4Cr Coating on CA6NM Steel

2017 ◽  
Vol 751 ◽  
pp. 79-83 ◽  
Author(s):  
Anurag Hamilton ◽  
Ashok Sharma ◽  
Upender Pandel
Keyword(s):  
Erosion Resistance ◽  
Solid Particle Erosion ◽  
Impingement Angle ◽  
X Ray ◽  
Hydro Turbine ◽  
Air Jet ◽  
Hvof Process ◽  
Coating Microstructure ◽  
Turbine Steel ◽  
Ca6nm Steel

In the present investigation, WC–10Co–4Cr coating was deposited by high velocity oxy-fuel (HVOF) process on CA6NM hydro turbine steel to improve its erosion resistance. The coating was characterized in term of crossectional microstructure, phase, microhardness and fracture toughness using a field emission scanning electron microscope (FESEM), X-ray diffractometer and microhardness tester respectively. Solid particle erosion resistance of the substrate and coating were evaluated by air jet erosion tester at two different impingement angles (30° and 90°). Coating microstructure has shown a homogeneous and well-bonded laminar morphology. The microhardness of the coating was observed more than three times higher than CA6NM substrate. This resulted in significant improvement in erosion resistance of coated CA6NM steel at both impingement angles.

SOLID PARTICLE EROSION RESISTANCE OF HVAF-SPRAYED WC-10Co-4Cr COATING ON CA6NM STEEL

2017 ◽  
Vol 24 (Supp01) ◽  
pp. 1850011 ◽  
Author(s):  
ANURAG HAMILTON ◽  
ASHOK SHARMA ◽  
UPENDER PANDEL
Keyword(s):  
Impact Velocity ◽  
Erosion Resistance ◽  
Test Results ◽  
Air Jet ◽  
Cumulative Volume ◽  
Uncoated Steel ◽  
Before And After ◽  
Turbine Steel ◽  
Ductile Behavior ◽  
Ca6nm Steel

In the present investigation, WC-10Co-4Cr coating was deposited by high velocity air-fuel (HVAF) process on CA6NM hydro turbine steel. A detailed microstructural and phase compositional study was carried out on the coating. Mechanical properties of the coating were also evaluated. WC-10Co-4Cr coating showed a homogeneous, well-bonded structure with low porosity, which is mainly attributed to less decarburization of WC. Erosion resistance of the coating was evaluated by air jet erosion tester at three different impingement angles (30[Formula: see text], 60[Formula: see text] and 90[Formula: see text]) for 35 and 70[Formula: see text]m/s impact velocities. The FESEM micrographs were taken, before and after erosion tests, to determine the erosion mechanism. The test results revealed that the coating protects the substrate at 30[Formula: see text], 60[Formula: see text] and 90[Formula: see text] impingement angles. At 70[Formula: see text]m/s impact velocity, uncoated and coated steel showed higher cumulative volume loss than in the case of 35[Formula: see text]m/s impact velocity. It was observed that uncoated steel showed a ductile behavior during erosion and WC-10Co-4Cr coating showed mixed (ductile and brittle) mode of fracture during erosion.

Water-droplet erosion behavior of high-velocity oxygen-fuel-sprayed coatings for steam turbine blades

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Dingjun Li ◽  
Peng Jiang ◽  
Fan Sun ◽  
Xiaohu Yuan ◽  
Jianpu Zhang ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Water Droplet ◽  
Erosion Resistance ◽  
Turbine Blades ◽  
Impingement Angle ◽  
Erosion Behavior ◽  
Water Droplet Erosion ◽  
Steam Turbine Blades ◽  
Oxygen Fuel ◽  
Sprayed Coatings

Abstract The water-droplet erosion of low-pressure steam turbine blades under wet steam environments can alter the vibration characteristics of the blade, and lead to its premature failure. Using high-velocity oxygen-fuel (HVOF) sprayed water-droplet erosion resistant coating is beneficial in preventing the erosion failure, while the erosion behavior of such coatings is still not revealed so far. Here, we examined the water-droplet erosion resistance of Cr3C2–25NiCr and WC–10Co–4Cr HVOF sprayed coatings using a pulsed water jet device with different impingement angles. Combined with microscopic characterization, indentation, and adhesion tests, we found that: (1) both of the coatings exhibited a similar three-stage erosion behavior, from the formation of discrete erosion surface cavities and continuous grooves to the broadening and deepening of the groove, (2) the erosion rate accelerates with the increasing impingement angle of the water jet; besides, the impingement angle had a nonlinear effect on the cumulative mass loss, and 30° sample exhibited the smallest mass loss per unit area (3) an improvement in the interfacial adhesion strength, fracture toughness, and hardness of the coating enhanced the water-droplet erosion resistance. These results provide guidance pertaining to the engineering application of water erosion protective coatings on steam turbine blades.

Characterization of WC-Co Coatings Using HP/HVOF Process

1996 ◽  
Author(s):  
S.Y. Hwang ◽  
B.G. Seong ◽  
M.C. Kim
Keyword(s):  
Wear Resistance ◽  
X Ray Diffraction ◽  
High Carbon ◽  
Properties Of Coatings ◽  
X Ray ◽  
Hvof Process ◽  
Number Of Passes ◽  
Oxygen Fuel

Abstract To maintain surface roughness of process rolls in cold rolling steel plants, WC-Co coatings have been known to be effective ones. In this study, a high pressure/high velocity oxygen fuel (HP/HVOF) process was used to obtain WC-Co coatings. To get the best quality of coatings, WC-Co coatings are sprayed with numerous powders made by various processes. These powders include agglomerated sintered powders, fused-crushed powders, extra high carbon WC-Co powders and (W2C, WC)-Co powders. After spraying, properties of coatings such as hardness, wear resistance. X-ray diffraction, and microstructures were analyzed. For coatings produced by agglomerated-sintered powders, hardness of the coating increased as power levels and the number of passes were increased. In case of the coatings produced by fused-crushed powders, a very low deposition rate was obtained due to a low flowablity of the powders. In addition, the WC-Co coatings sprayed with extra carbon content of WC-Co did not show improved hardness and wear resistance. Also, some decomposition of WC was observed in the coating. Finally, the coatings produced by (W2C, WC)-Co powders produced higher hardness and lower wear resistance coating.

Synergistic effect of Al2O3/TiO2 reinforcements on slurry erosion performance of nickel-based composite coatings

2017 ◽  
Vol 232 (8) ◽  
pp. 974-986 ◽  
Author(s):  
Rajeev Kumar ◽  
Sanjeev Bhandari ◽  
Atul Goyal
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Mass Loss ◽  
Erosion Resistance ◽  
Slurry Erosion ◽  
Specific Mass ◽  
Operational Parameter ◽  
X Ray ◽  
Specific Mass Loss ◽  
Scanning Electron

Various aspects such as development, experimentation, and analysis have been covered in the present work to examine the behavior of test coatings under slurry erosion. The primary objective of the present study was to establish the specific mass loss from the test coatings under various slurry environmental conditions and highlights the importance of the addition of alumina in improving the slurry erosion resistance of Ni-TiO2 coating. To attain this objective, two powder compositions, viz. Ni-20TiO2 and Ni-15TiO2-5Al2O3 were deposited onto the CA6NM grade hydro-turbine steel using high velocity frame spray process. The microstructural characterization of the coatings was done by employing surface roughness tester, scanning electron microscope/energy-dispersive X-ray spectroscopy, and X-ray diffraction techniques, whereas mechanical analysis was carried out using micro-hardness and bond strength tester. The slurry erosion tests were performed using an indigenously fabricated high speed slurry erosion test rig at different levels of rotational speed, average particle size of erodent, and slurry concentration in order to explore their effects on slurry erosion performance of test coatings. The slurry erosion results, as well as scanning electron microscope observations of eroded specimens, revealed higher slurry erosion resistance of Ni-15TiO2-5Al2O3 coating in comparison with Ni-20TiO2 coating. Furthermore, each operational parameter was found to have a proportional effect on specific mass loss in case of both the coatings.

Effect of erosive parameters on solid particle erosion of cotton fiber–based nonwoven mat/wooden dust reinforced hybrid polymer composites

2021 ◽  
pp. 152808372110642
Author(s):  
Sachin Tejyan
Keyword(s):  
Solid Particle ◽  
Impact Velocity ◽  
Cotton Fiber ◽  
Polymeric Composites ◽  
Solid Particle Erosion ◽  
Erosion Wear ◽  
Impingement Angle ◽  
Particle Erosion ◽  
Fiber Loading ◽  
Wide Range

Abrasive particle-induced erosive wear of polymeric engineering components is a major industrial issue. The research of solid particle erosion characteristics of polymeric composites becomes essential due to operational needs in dusty conditions. Nonwovens are now employed in industrial applications for polymeric composites. Nonwoven products are made from a wide range of raw materials, ranging from synthetic to natural fibers. This work finding the effect of nonwoven cotton fiber (5, 10, and 15 wt.%) loading on the physical, mechanical, and erosion wear of fixed wooden dust (4 wt.%) filled hybrid epoxy composites. Experimental results reveal improved impact strength, hardness, and compressive and tensile strength with an increment of fiber loading from 5–15 wt.%. The density of the composites was found to increase, whereas void content decreases with an increase in cotton fiber. The erosion wear of the composites has been studied using an L27 orthogonal array to assess the effects of various parameters such as fiber loading, erodent size, impact velocity, impingement angle, and stand-off distance. The erosion wear increased with impact velocity and remained highest for 60° of impingement angle. The most significant parameter affecting the erosion wear was determined as impact velocity followed by impingement angle. Surface morphologies of eroded samples reveal the fiber pull-out, and fiber breakage was the prominent phenomenon for the erosion wear of the evaluated composites.

Micro-nano multilayer structure design and solid particle erosion resistance performance of CrAlNx/CrAlN coating

Vacuum ◽  
2020 ◽  
Vol 172 ◽  
pp. 109064 ◽  
Author(s):  
Di Wang ◽  
Songsheng Lin ◽  
Lingyun Liu ◽  
Hongzhi Yang ◽  
Jing Shi ◽  
...  
Keyword(s):  
Solid Particle ◽  
Multilayer Structure ◽  
Erosion Resistance ◽  
Structure Design ◽  
Solid Particle Erosion ◽  
Particle Erosion ◽  
Resistance Performance
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