Slurry Erosion Performance of High-Velocity Flame-Sprayed Ni-20Al 2 O 3 and Ni-10Al 2 O 3 -10TiO 2 Coatings Under Accele
- PDF / 3,362,021 Bytes
- 13 Pages / 595.276 x 790.866 pts Page_size
- 47 Downloads / 189 Views
PEER REVIEWED
Slurry Erosion Performance of High-Velocity Flame-Sprayed Ni-20Al2O3 and Ni-10Al2O3-10TiO2 Coatings Under Accelerated Conditions Rajeev Kumar1 • Sanjeev Bhandari2 • Atul Goyal3
Submitted: 28 February 2017 / in revised form: 24 June 2017 ASM International 2017
Abstract The slurry erosion wear behavior of Ni-20Al2O3 and Ni-10Al2O3-10TiO2 coatings, deposited by high-velocity flame-sprayed technique, has been evaluated in the present investigation. A series of slurry erosion tests were conducted on the deposited surfaces, using an indigenously developed slurry erosion test rig under varying environmental conditions. The effect of identifying operational parameters like rotational speed, average particle size of erodent and erodent concentration on erosion behavior was also evaluated. Surface roughness tester, scanning electron microscope and XRD apparatus were utilized as surface characterization tools, whereas Vickers’s microhardness tester and bond strength tester were employed for mechanical analysis. The SEM observations of eroded specimens were observed to be lying in close proximity to the reported experimental results. Irrespective of the test conditions, Ni-10Al2O3-10TiO2 coating showed better results of slurry erosion performance in comparison with Ni-20Al2O3 coating. Further, each operational test parameter revealed a proportional effect on the erosion rate of both the coatings. Keywords alumina-titania erodent HVFS nickelalumina nickel-alumina-titania specific mass loss
& Sanjeev Bhandari [email protected] 1
IKGPTU – Research Scholar, Mechanical Engineering, Jalandhar, India
2
Baba Banda Singh Bahadur Engineering College, Fatehgarh Sahib, Fatehgarh Sahib, India
3
Lala Lajpat Rai Institute of Engineering and Technology, Moga, Punjab, India
Introduction Many hydropower projects, especially in the Himalayan and northeastern regions of India, regularly faces slurry erosion problems in turbines, which directly affects the overall efficiency of power generation units (Ref 1). The problem becomes highly complex during the monsoon days due to the sudden increase in solid (especially quartz) concentration levels (Ref 2). However, sometimes, it is better to shut down the hydro-plants to prevent the major losses. Normally, the decision of shutting down the whole plant is taken when the solid content exceeds the threshold value (usually 5% of sand) of solid concentration (Ref 3). The turbine components vulnerable to slurry erosion are buckets, impellers, nozzles, spear and needles, in the case of impulse turbines, and guide vanes, impeller blades, faceplate and labyrinth seal, in the case of reaction turbines (Ref 4). Martensitic stainless steel, CA6NM (13/4), is commonly used for the manufacturing of some of the hydro-turbine components. Among the other structural steel grades, such as CF8M, 16Cr5Ni and 13Cr1Ni, CA6NM (13/4) remains a preferred choice due to its high impact strength and fracture toughness properties (Ref 5). However, during the long duration of exposure t
Data Loading...
