COATING SOLUTIONS .... COATING SOLUTIONS ....National Thermospray, Inc.
METALLIZING PROCESS
PROJECTS OF INTEREST
HYDROELECTRIC US ARMY CORPS USACERL REPORT ON HVOF
National Thermospray, Inc. would like to introduce your company to a recently new field process called High-Velocity Oxygen Fuel (HVOF) thermal spray service. The desirable properties of HVOF is High Density and even to a Negligible Porosity, resulting from high spray-particle velocities produced by a hot combustion-driven, high-speed gas jet. Although HVOF spray process represents a new coating technology, in principle, it amounts to a small rocket engine. HVOF is a supersonic process which delivers well over 7000 fps of velocity and can exceed bond strengths of 12,000 psi. It is an extremely versatile system that offers an unlimited range of possibilities to industries with extreme corrosion and wear environments such as chemical and refinery, agriculture, marine, hydroelectric plants, pulp and paper mills to name a few. If you need to maximize the life of your present of future equipment, than HVOF maybe the answer to your particular problems. HVOF coatings is emerging as one of the most cost effective ways to combat wear and corrosion.
National Thermospray, offers a turnkey process with state of the art techniques and equipment, which includes robotics and experience, that can save your company time and money. We hope the following technical information will significantly change the way you look at saving and protecting your equipment in the near future. If you have any questions or need further information about this service, please contact us.
Basic Principles of Operations
The HVOF unit uses an oxygen-fuel mixture consisting of propylene, propane, or hydrogen, depending on users coating requirements to produce the highest quality coating available today. Fuel gases are mixed in a proprietary siphon system in the front portion of the HVOF gun. The thoroughly mixed gases are ejected from the nozzle and ignited externally to the gun. Ignited gases form a circular flame configuration which surrounds the powdered material as it flow through the gun. Combustion temperature is between 5000F to 6000F depending on fuel. The circular flame shapes the powder stream to provide uniform heating, melting, and acceleration (See Diagram). Pre-selected oxygen, fuel and air values are specified for each material to optimize dwell time in the flame.
Typical Coating Properties
The key success of HVOF is the extremely High Kinetic Energy that is being produced and transferred between the HVOF unit and the substrate using space-age rocket propulsion technology. Typical velocities approach 5000 fps to over 7200 fps depending on which hardware is selected.With both thermal and kinetic energy, the high velocity particles are practically embedded into the substrate to form a superior coating with the following characteristics:
High Density The coatings produced though HVOF develop very high densities because of the high kinetic energy associated with this process.
High Bond Strengths (in excess of 12,000 psi)
Zero Porosity ( with no interconnecting porosity )
Metal Working Capabilities
Essentially Stress Free
Greater Hardness
Greater Thickness
Low Thermal Input ( substrate temperature less than 300 degrees F which insures original mechanical properties and with No Stress Relieving Required)
NATIONAL THERMOSPRAY, INC.
5120 Oak Ave
Pasadena, Texas 77503
Contact Ken Norris
OFFICE: 281-373-0609 or 281-991-1133
Cell 713-898-6844
FAX: 281-991-9911
knorris@nationalthermospray.com