Achieving An Alternative Sealing Solution By Combining HVOF And HVAF
HVOF/HVAF is an alternative sealing solution worth considering for many industries. This new high velocity flame spray process combination replaces coatings such as chrome. HVAF stands for High Velocity Air Fuel and HVOF stands for High Velocity Oxygen Fuel.
Systems and Seals
Compliant materials and elastomers usually come to mind at the mention of seal systems and seals in general. The sealing surface, the backbone of the sealing system, is seldom thought of. When it comes to elastomeric members, many changes have been made. Also changing, however, are application methods and materials used with the sealing surface. The hard chrome industry is being benefited by one notable change – the combining of HVOF and HVAF processes. Who reaps the rewards of these benefits? Rework and repair shops servicing pistons, hydraulic cylinders, landing gear, gas and oil drilling machinery, heavy equipment, and paper and pulp mill rolls are just a few examples.
HVAF And HVOF Processes
Spray powders are used in HVAF application guns. In a heating and acceleration process using fuel gas and hot compressed air, the powders are applied. Fuel gas can be natural gas, propylene, high butane LPG, or propane. The coatings that result protect against corrosion, erosion, and abrasion. They are beneficial for surface preservation, conservation, and restoration. Frequently, HVAF is used inside pipes.
At military depots and throughout the aircraft industry in general, HVOF is widely utilized. As an example, HVOF coatings are applied on new aircraft landing gear cylinders. The same technology is used on other major components: i.e., propeller hubs, helicopter dynamic components, engines, aircraft hydraulic actuators, and more. These coatings demonstrate less corrosion and wear and are known for their lasting qualities.
The Processes Combined
The combining of these two processes, HVOF and HVAF, supplies an offering of the highest possible industry spray rates. Breakthrough results have been achieved by the process optimized by the use of temperature elevating oxygen and air as a primary oxidizer. Best of all, this high-quality coating is reliable but affordable.
A Look at the Basic Benefits of HVOF and HVAF
So what were the basic characteristics of this combined process that makes it such an attractive option? Here it is in a nutshell:
- Equipment used in the process produces extremely thin chrome replacement coating (if desired) that is porous free. The coating can be polished as needed.
- When compared to even state-of-the-art HVOF, higher quality is delivered by the HVAF mode resulting in high DE and higher spray rates (meeting HVOF specs).
- When compared to the process, cost per kilogram deposited may be half as much.
- Extremely dense, hard metal coatings are delivered through the process.
What does all of this mean for industries? The combined HVOF/HVAF system produces high-quality, economical coatings with reliable, easy to use equipment.
At A&A Coatings, we use the latest, proven methods of application for our coating processes. If you would like to discuss high velocity flame spray processes and what they can do for your industry, speak to one of the knowledgeable representatives at A&A Coatings today.