HVOF Tungsten Carbide Very small ID

1/4 inch ID and 80 mm ID examples


Sprayed from the OUTSIDE Diameter, using an OD Spray Gun, model C6.  As small as 6.3 mm diameter, depth 10.6 mm depth of the coating. 


Another example HVAF C coating, Kermetico have sprayed Tungsten Carbide 80 mm ID spray from the outside, depth 167 mm and 183 mm


See image  for WC-17Co spraying with C6 inside the bushing 



. The bushing ID was 6.3 mm. The powder was 45/5 micron size, coarse WC (2.5 micron grain size of WC). Yes, 10. 6 mm depth of the coating.

The 6 mm ID bushings were sprayed to the depth of 10.6 mm (full thickness)

The 80 mm ID valves were sprayed to the depth of 6.6 inches (167 mm) and 7.2 inches (183 mm). Test pipe was sprayed with the same setting - See met. pictures attached for this pipe.

Shallow angle spraying is a specific feature of Convertible system. A new “discovery”of HVAF C process. With HVAF, you can hardly deposit anything at angles lower than 40 degree. With HVOF deposition is possible at 30 degrees or slightly lower – but the coating quality is terrible. With HVAF C = Convertible, you can “tune” particle temperature, creating excellent coating quality at very shallow spray angles.

Note that many jobs in ID are made with OD-guns, spraying under the shallow angle.

We were spraying into 6 mm ID with 32 degrees (WC-17Co) and into 80 mm ID at 25-27 degrees (WC-10Co-4Cr) with C6 gun, 50 SLPM oxygen. “Undetectable” porosity, hardness 1050-1200 HV300.


Click for report on metallurgy for 6 mm ID


Click for report on metallurgy for 80 mm ID

Thermal Spray Singapore Blog

Consider HVOF/HVAF As Alternative Sealing Solution New combination process provides alternative to chrome and other coatings.

by Dale Moody, Peter Foy | Jun 22, 2017

hydraulicspneumatics.com



Combining the Two Processes

HVAF and HVOF have been merged into a single system (HVAF/HVOF) that offers the highest spray rates in the industry in either mode. The HVAF/HVOF thermal spray system uses air as the primary oxidizer and oxygen to elevate the temperature, thereby optimizing the process with breakthrough results. The addition of oxygen provides all existing HVOF owners and new prospects a reliable and less expensive coating with a high quality. Existing HVOF specifications can be achieved and exceeded using the convertible system. Users can achieve a 0.002-in. thick corrosion-proof coating that holds up under high pressure and can be polished to an RA 4 finish without grinding.  

In comparison to the HVOF process, the combined process provides a significant increase in the Vickers Hardness of WC-10Co-4 Cr coatings.  Weight loss during silt erosion testing is less than 1/3 of the weight loss of the same coating applied with the traditional HVOF process. Furthermore, the cost per kilogram deposited can be as much as half that of using the HVOF process. 

In summary, the HVAF/HVOF system produces very economical, high quality coatings with easy to use, reliable equipment.


full article  

HVOF coating on 80 Tungsten carbide

Pipeline Coatings by HVAF

We can coat pipelines or provide the equipment and materials for coating, and application know-how.  In San Francisco  We coat vessel and pipeline spools on a regular basis. 


check out our latest TDS on pipeline coatings

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