Improving the reliability of power complex equipment by electric arc spraying

2021 ◽  
Vol 2021 (10) ◽  
pp. 38-46
Author(s):  
A.V. Hruzevych ◽  
◽  
V.V. Shvets ◽  
2015 ◽  
Vol 1111 ◽  
pp. 211-216
Author(s):  
Bogdan Florin Toma ◽  
Iulian Ionita ◽  
Diana Antonia Gheorghiu ◽  
Lucian Eva ◽  
Costică Bejinariu ◽  
...  

Influence of the process parameters and geometry of the spraying nozzle on the properties of titanium deposits obtained in wire arc spraying. Wire arc spraying is a process in which through minor modifications of the spray parameters, they can have a major impact on the coatings properties. In this paper there is presented a study on the influence of process parameters and fluid dynamics of the atomization gas on the properties of titanium deposits (14T - 99.9% Ti). For this there were used three different frontal spraying nozzles, having different geometries, and were varied the spraying gas pressure and the electrical current on three levels. There were evaluated the particles velocity, coating density, chemical composition and characteristic interface between deposition and substrate. Obviously, the high speed of the atomization gas determinate the improving of all properties, but in the same time increased the oxide content in the layer. However, the oxidation can be drastically reduced if the melting and atomization of the wire droplets is produced at the point of formation of the electric arc, and the spraying jet is designed to constrain the electric arc. The assessment of deposits adherence allowed the observation of process parameters that contribute to its improvement.


2015 ◽  
Vol 811 ◽  
pp. 19-23 ◽  
Author(s):  
Gheorghe Matache ◽  
Cristian Puscasu ◽  
Alexandru Paraschiv ◽  
Oana Trusca

Thermal sprayed Mo coatings deposited on steel support deposited by electric arc and atmospheric plasma spray were investigated. Microstructural investigation of the coatings showed that in both variants the splats formed by rapid solidification and splashing during the impact with the substrate have irregular shape, exhibit cracks and scattered debris. The measured average equivalent diameter of the splats and the calculated average diameter of the particles that generated the splats are higher for electric arc spraying. Using the measured and calculated data it was descibed the relathionship between splats diameter, splats thickness and flattening degree. Some intrinsec properties of the coatings as roughness, hardness and bond strength were measured. All these properties are influenced by the splat size. Lower size of the splats lead to reduced surface roughness, higher hardness and higher bond strength of the coatings.


2014 ◽  
Vol 989-994 ◽  
pp. 270-275
Author(s):  
Jian Jun Fang ◽  
Yun Jing Song ◽  
Zhuo Xin Li

The research uses electric arc spraying with low cost and convenient operation to prepare four TiB2 particle reinforced composite coatings with high bonding strength and uniform tissue. It makes comparative study on elevated temperature erosion actions of coating and 45CT of electric arc spraying. The results indicate the coating has excellent erosion wearing resistance. TiB2 particles in M-TiB2 coating have small size, have good unity with metallic matrix, and are distributed on metallic matrix with high hardness relatively uniformly, and porosity of coating is low. The coating has excellent erosion resistance.


2021 ◽  
Vol 11 (18) ◽  
pp. 8444
Author(s):  
Irina Zakharova ◽  
Vyacheslav Royanov ◽  
Valeriy Chigarev

The paper aims to investigate the airflow dynamics of electric-arc spraying (EAS) with airflow pulsation. The study is focused on the dynamic structure of the airflow with an obstacle in the form of crossed electrodes at the steady and the pulsating air supply (with a frequency up to 120 Hz). The work was fulfilled using a computer simulation, the airflow “shadow” photo visualization, and the microstructure characterization of the coatings formed. It was found that when air flows along the crossed electrodes with a gap of 2 mm, a depression zone appears in the flow with a pressure drop from 0.56 MPa to 0.01 MPa. The air pulsation resulted in a change in a flow’s dynamic structure towards an increase in the length of the depression zone, which covers most of the arc, affecting the liquid metal oxidation. It is established that the frequency of a droplet formation should match the frequency of the airflow pulsation to minimize the metal oxidation. With the air pulsating at about 65 Hz, the oxide volume fraction in the aluminum coating was reduced by 3.6 times compared to the steady airflow. EAS with airflow pulsation has the potential for technological cost reduction.


Alloy Digest ◽  
2003 ◽  
Vol 52 (6) ◽  

Abstract Sulzer Metco 8500 is a nickel-chromium alloy wire for electric arc spraying. The nominal composition is Ni-45Cr, and applications are in the protection of power-plant boiler tubes. This datasheet provides information on composition, physical properties, and microstructure. It also includes information on machining, joining, and surface treatment. Filing Code: Ni-608. Producer or source: Sulzer Metco.


Author(s):  
J. Musil ◽  
V. Dolhof ◽  
E. Dvorácek

Abstract Water turbine parts damaged by cavitation erosion (CE) and/or slurry erosion (SE) may cause excessive operational costs for plants worldwide. The damages can be reduced by choosing more resistant materials and right technology in the first-production or at repair and overhaul. Thermal spray technologies have a great potential in the field of repairing works. Thick multilayered coatings deposited by wire electric arc spraying (WAS) has been developed and applied as CE and SE protection at the repair of stationary Francis turbine blades. Repair technology by WAS was performed on large eroded areas (1-3 m3) of preguide blades of Francis turbine: 1) local damaged depths 30-35 mm maximum were repaired by sprayed materials, 2) subsequently wire arc spraying of functional coating was applied. Three types of functional coatings with total thickness 10 mm a) duplex high - Cr stainless steel with NiAl bond coat, b) graded NiAl - Cr stainless steel coatings, and c) multilayered graded NiAl - Cr stainless steel coatings were compared by means of stress measurements and structural analysis. The coating structure influences very strongly the residual stress level and adhesive-cohesive strength. Multilayered graded NiAl - Cr stainless steel coatings showed the best results and were sprayed on water turbine blades in 4 Czech water power station during regular cut-off repair periods. After 30 - 36 months' continuous operation, Francis turbine blades repaired by WAS technology show better behaviour in comparison with original material from the point of wear resistance, reliability, cost-effect and life-time.


2015 ◽  
Vol 0 (1) ◽  
Author(s):  
Viacheslav O. Roianov ◽  
Volodymyr I. Bobikov

Sign in / Sign up

Export Citation Format

Share Document