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2454 |
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Research and development of new power-saving cumulative-detonation sprayer and equipment for thermal spraying applications (CDS-HVOF) |
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Yuriy Tyurin / E.O.Paton Electric Welding Institute, NASU , Ukraine Oleg Kolisnichenko/ E.O.Paton Electric Welding Institute, NASU, Ukraine |
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Current technology and equipment of HVOF is highly inefficient with respect to both electric power consumption and use of process gasses. It is expected that the reduction in both electric power and process gasses will be 70% to 90%. Cumulative-Detonation Sprayer for generation of gas flows at a velocity of up to 3000 m/s. The sprayer will use non-stationary modes of detonation combustion of fuel gas mixtures. These modes provide independence of the velocity of combustion products from the amounts of combustible components of the fuel mixture. In addition, energy cumulation in specially profiled chambers makes it possible to form a multi-frontal flow of detonation combustion products. This significantly adds to the efficiency of energy transfer to the dispersed sprayed particles and results in reduced power utilization. Combustion of the fuel mixtures in specialized chambers offers wide capabilities in terms of control of the velocity, temperature and composition of the combustion products, which allows realization of various thermal spraying technologies, such as Cold Spray or HVOF. Preliminary investigations of the Cumulative Detonation Sprayer of High Velocity Oxygen Fuel (CDS-HVOF) concept using various elements of existing equipment have proven the correctness of this technique. Thermal spraying of 1.2 kg of standard powders, e.g. Cr2C3-NiCr, resulted in 3-4 m3/h consumption of the fuel mixture components and material utilization factor of up to 80 % and coating hardness of 12,000 MPa. It is a known that fuel mixture consumption for deposition 1 kg of these standard powders by the HVOF technology is up to 20 m3/h. Research and Development of new power-saving cumulative detonation thermal spray equipment capable of applying standard and novel coatings having exceptional quality and mechanical properties. Furthermore, that equipment will have a wide and controllable spectrum of thermal input to the substrate thus allowing for coating of variety of materials. |