Specialist HVOF and Metal Spraying
The success rate of our Powder Metal Spraying technology has been remarkable thus far. The advantage of metal spraying, using this “cold” process, is that components are heated to a maximum of 300F. This ensures that the component does not distort as in welding, and the metallurgical composition is left unchanged, free of embrittlement and porosities, two factors which can lead to failure.
The range of products which can be sprayed include, but are not limited to, Cast Iron, Stainless Steel, Bronze, Ceramics and high chrome materials, to name a few. We can repair a shaft or other component and give it a longer service life than the original by choosing a hard wearing overlay during repair.
In addition to the above, Qualitech Machining Services Limited has now installed a state of the art HVOF (High Velocity Oxy Fuel) Metal Spraying system.
HVOF equipment represents the best available coating system, particularly for Tungsten Carbide, and has been in use for over 20 years in the aircraft industry and primarily used to spray Jet Engine components and High Speed Compressor Rotors. It offers the best bond strength and reliability of all the metal spraying processes, and has been rated as a minimum of 10,000 psi bond strength, simply because the best epoxies used to carry out the bond strength tests fail at 10,000 psi, not the coating!
The HVOF spraying gun is similar to a small rocket engine and uses a combination of A1 Jet fuel and 1000cfm of Oxygen, this mixture is then ignited by an ignition system to start the process. The entire process is computer controlled and the fuel, ignition and powder sequence is closely monitored. The HVOF flame exits the gun at a supersonic speed of 2500 feet per second. The powder is introduced into the flame, melted and spray deposited onto the job. Maximum job temperature is 300F which means there is no metallurgical change or distortion to the base material. Machining is done by grinding using only special Diamond abrasive wheels. We have also installed state-of-the-art polishing equipment to achieve a surface roughness of a few micro inches, which is smoother than chrome plating, if required.
Powders used in the HVOF process can be widely varied in composition and can be ordered specifically for your requirements. We presently stock powders for use on Turbine and Compressor rotors and other hard wearing applications. They have been approved by users, such as Pratt & Whitney, GE, Rolls Royce and Boeing to name a few.