International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 09 Issue: 05 | May 2022
p-ISSN: 2395-0072
www.irjet.net
Effect of Annealing on Erosion Behavior of Atmospheric Plasma Spray and High Velocity Oxy Fuel Sprayed WC-Cr3C2-Ni Coatings. Akash Deshpande1, Nikhil Bhusari2, Om Kulkarni3, Shubhankar Jadhao4 1,2,3,4 Student,
Dept. of Mechanical Engineering, Pillai College of Engineering, Maharashtra, India. ---------------------------------------------------------------------***--------------------------------------------------------------------impact angle, and impingement velocity is more important ABSTRACT - High temperature solid particle erosion is a major problem in pressure vessels and turbo machineries. A detailed tribological study becomes essential to investigate the right coating method to prevent it and enhance its mechanical and physical properties. The study focuses on Wc-Cr3C2Ni coating, thermally sprayed APS and HVOF considering pre available literature. The coating was subjected to heat treatment and then to solid particle erosion testing. Annealing was done in cycles at 550-degree temperature at intervals to influence its properties. Solid particle erosion was done at 450and 575-degree temperature using Alumina powder as eroded at 30- and 90-degree impact angles. SEM and EDX analysis were done as a part of characterization and hardness was noted before and after testing. It was observed that WcCr3C2Ni coating superior hardness makes them ideal for use on steel substrates to improve erosion resistance. Also, both coatings showed improved hardness, HVOF has more wear resistance and hardness gain than APS. Thus, making the coating suitable for boiler tubes, turbine valves and other pressure vessels and turbo machineries to resist erosion and enhance properties Key Words: Annealing, Elevated temperature, Air particle erosion, Thermal spray coating, Microhardness, SEM.
1. INTRODUCTION In most fluid interaction engineering applications, hightemperature erosion produced by impingement of solid particles suspended in the fluid is a serious concern. The high temperature solid particle erosion has a significant contribution to the failure of components in a coal-fired power plant like steam gas turbines, boiler tubes. As a result, substantial financial losses are unavoidable during component maintenance and replacement. Stainless steel and nickel alloys are the most widely utilised materials for these components. Tungsten carbide-based coatings' superior hardness makes them ideal for use on steel substrates to improve erosion resistance. For the deposition of carbide-based coatings, thermal spray versions are useful. Because they offer outstanding mechanical features such as increased hardness, fracture toughness, and cohesive strength, atmospheric plasma spray (APS) and high-velocity oxy-fuel (HVOF) are favoured variations. As a result, examining the erosion resistance of coatings under varying operating conditions such as temperature, © 2022, IRJET
|
Impact Factor value: 7.529
|
than the other characteristics. Among commercially available formulations, WC-Cr3C2–Ni outperforms other WC compositions in terms of high-temperature wear and oxidation resistance. The research focuses on the erosion performance of WC-Cr3C2–Ni coatings coated by atmospheric plasma spray (APS) and high velocity oxy-fuel (HVOF) in the presence of alumina (Al2O3) entrained in the air stream.
1.1 LITERATURE REVIEW The HVOF coating exhibits the best wear resistance because of its higher hardness and toughness and better oxidation characteristics. The tribological performance of the APS coating is unsatisfactory because of its inferior mechanical property and oxidation resistance. With increasing annealing temperature, annealed coatings show a minor increase in hardness and better toughness, as well as a steady decrease in internal stress, which is especially noticeable beyond 200 C. The wear rate reduces as the annealing temperature rises, reaching its lowest point at 400 C before recovering to a high point at 500 C (25). WC-Co coatings of different thickness (250, 350, 400 μm) were deposited onto the steel 45 Tungsten carbide/cobalt (WC-Co) coatings deposited by thermal spray technique. Air annealing at 500 °C temperature resulted in surface morphology changes similar for all WC-Co coating (18). The substrate steels' solid particle erosion rate is highest at 30° impact angles, indicating that they are behaving in a ductile manner. The substrate steels have shown little low mass loss as compared to the HVOF coatings due to embedment of sand particles. (20)
2. MATERIAL SELECTION The high temperature solid particle erosion has a significant contribution to the failure of components in a coalfired power plant like steam and gas turbines, boiler tubes. Stainless steel and nickel alloys are the most widely utilized materials for these components. Due to inferior erosion and high-temperature corrosion resistance, the useful service life of these components is low. Superior hardness of tungsten carbide-based coatings makes them favorable on steel substrate to enhance erosion resistance. Because to catastrophic oxidation, the majority of WC-based coatings lost their functional capabilities over 500°C. Mixed carbidebased coating, such as WC-Cr3C2–Ni, is an exception because the presence of Cr or Cr3C2 helps to increase oxidation ISO 9001:2008 Certified Journal
|
Page 101