| Abstract: |
Thermal spraying processes are traditionally expensive in terms of initial capital investment, as well as operating expenses due to the high cost of consumable materials. The recent economic crisis has brought additional pressure on manufacturers to reduce costs in order to be competitive on the global market. Therefore, there is a need for more efficient and economical thermal spraying processes and equipment.
This paper presents a low cost HVAF system, which can be used for various types of surface protection technologies, which include highly efficient surface blasting and multi-purpose thermal spraying processes. The core of the system is a HVAF gun, to which various types of attachment can be fit, depending on the process used, and a controller, capable of switching between the processes.
For surface preparation, the designed HVAF system, thanks to the high velocity of abrasive particles obtained in the thermal jet, can produce a deep surface finish profile, which is important for corrosion protection coatings such Zn-Al. In comparison with conventional abrasive blasting, HVAF thermo-abrasive blasting proved to be considerably more efficient and productive.
For thermal spraying, the HVAF system can be used for spraying of wires for anticorrosion protection and powders for wear resistance. The HVAF thermal spray system was used for thermal spraying of Zn-Al wires, producing a much higher adhesion strength in comparison with wire-arc spraying, good anticorrosion properties and competitive production rates. Also, high quality WC-Co coatings were obtained with the HVAF system, which runs on liquid fuel and compressed air, significantly reducing the running cost of the coating process in comparison with HVOF.
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