- Powder Flame Spray Gun
- Wire Flame Spray Gun
- Rod Flame Spray Gun
This process is basically the spraying of melted material onto a surface to provide a coating. The substantial powder form is melted in a flame (oxy-acetylene or hydrogen most common) to form a fine spray. When the spray contacts the prepared surface of the substrate substantially, the fine molten droplets rapidly solidify forming a coating.
This flame spray process is also called the cold process (relative to the substrate substantial being coated) as the substrate temperature can be kept low during processing avoiding damage, metallurgical changes, and distortion to the substrate substantial.
The main advantage of this flame spray gun process over the similar Combustion wire spray process is that a much wider range of substantial is easily processed into powder form giving a larger choice of coatings. The flame spray process is only limited by materials with higher melting temperatures than the flame can provide or if the substantial decomposes on heating.
Powder flame spray applications
- corrugation protective valves
- rolling equipment
- bearing blocks
- ventilators
- motors of extruder worms
- rollers
- shaft sleeve etc.
Wire Flame Spray Gun
The wire flame spray gun process uses metals and alloys in wire form as its spraying substantial, and combustion flame or electric arc as its heat source. The molten substances are sprayed onto the surface of the subject to form the coating.
All metals and alloys in wire form are available for the substantial, such as copper wire, bronze wire, stainless steel wire, high carbon steel, molybdenum wire, and low melting point metals including aluminum, zinc, and others.
Process Advantages
• Low capital investment
• Simple to operate
• Wire form cheaper than powder
• Deposit efficiency very high
• Portable system
• The preheating facility built-in, unlike arc spraying
• Possible to use the system in areas without electricity supply
How Does Flame Spray Work?
Mixing the gases, passing the mixture through a shot / sand blasting nozzle, and igniting the mixture results in a high-intensity flame. By feeding the wire or powder into the flame, the metal or ceramic is melted. The molten metal or softened ceramic is then atomized and projected onto the compressed air-sprayed item.
Because the coating mechanically bonds to the surface being sprayed, the surface is commonly roughened by grit blasting. The coating layer grows in thickness, typically from around 50 microns to several mm. Most corrosion coatings are no thicker than 500 microns. Some engineering coatings can be several millimeters thick.