Thermal metal coating technology has expanded and developed continuously, being applied in many different fields such as aerodynamics, nuclear, marine, oil and gas, mechanical engineering… The wire arc thermal spraying method can create conductive coatings for non-conductive materials or insulation, effective wear-resistant, anti-corrosion coatings. The following article will introduce double wire arc thermal spray aluminium coating technology.
Learn about wire arc thermal metal coating: Definition, equipment used to do it, factors affecting the process
Wire arc thermal spray metal coating possesses many advantages, widely applied in many fields. The following content will introduce the definition, standard equipment used to apply this technique, and three factors that directly affect the coating process.
Double-wire arc thermal metal coating method: Definition and characteristics
Wire arc thermal spraying, also known as double wire arc spraying, is a term that refers to the process of spraying metal or alloy onto a particular material surface. This method uses a double arc wire with opposite charges to melt metals and alloys in the form of wires. It then uses a stream of high-pressure compressed air to spray the molten compound onto the surface to be coated. This metal coating technology creates a protective layer with a high grip and bond to the surface.
This is a relatively simple technique to create protective and anti-corrosion coatings for many different material surfaces such as metal, plastic, glass, ceramic… Thermal spray coating – Wire arc can also create an excellent anti-slip surface, reducing friction. This coating method can also create technical coatings with good heat resistance. In addition, because the coating surface is smooth and less porous, so using this method to restructure or change the characteristics of degraded material surfaces.
The thermal spray protects and prolongs the life of structures, equipment, and ships in various environments, from the conventional to the extreme. In addition, these surface coatings are also essential to efforts to prolong the structure’s life. Metal coating can last up to 20 years, even in harsh environments, significantly reducing maintenance costs.
2. The equipment and machinery used in the process of double wire arc thermal metal coating
The BP-400 thermal arc sprayer is the commonly used tool to perform this metal coating technique. The feature of this machine is that it is portable and easy to transport. The BP-400 features a sturdy stand control cabinet and a “push” actuator. This line of thermal sprayers uses a 400 Amp power source and a 3.2mm diameter spray wire.
Osu Hessler 300A heat spray gun is indispensable in this method. Its design makes it easy for technicians to replace and assemble all the parts within minutes. This unit uses a powerful DC motor, providing high torque and continuous wire feeding. The spray gun offers a high level of safety over a broad spray range of 35 to 300 A. Equipping standard “open” or “closed” nozzles in the design will depend on the intended use. The diameter of the spray wire of the device is 1.60mm.
3. Factors affecting the metal coating process: Technical equipment, the operating mode of the device and peripheral factors
The size and shape of the nozzle can affect the metal coating process results. Technicians should choose a cylindrical nozzle with a nozzle diameter calculated according to the formula below:
d = (3 ÷ 6) mm.
The device’s operating mode, namely the double wire arc current capacity and the amount of gas consumption, will have a direct influence on the coating process. The specific power of the nozzle is calculated based on the formula:
N = (2,000 ÷ 10,000)KJ/kg.
Increasing N will lead to overheating and metal loss, but the coating will have a higher quality.
The formula of Heat Spray Angle in the range (65 degrees ÷ 90 degrees). The spray distance will depend on the formula:
L = (100 ÷ 300)mm.
Above is information about the wire arc thermal spraying method (definition, implementation equipment and impact factors); We hope it has brought you much valuable knowledge. Finally, to learn more about thermal spray metal coating technology in general and its main applications, readers can refer to the following articles: Metal coating: Industrial applications of material protection solutions.