Superfinishing of HVOF Applied Tungsten Carbide Coatings
|Publication Date:||1 June 2011|
This specification covers requirements for the superfinishing of High Velocity Oxygen/Fuel (HVOF) applied tungsten carbide thermal spray coatings.
Superfinishing is a process used to produce high quality surface finishes characterized by low Ra (roughness average), such as 8 μinch Ra or less, in comparison to conventional ground coatings as in AMS2449. See 8.2.6.
This process has been used typically to superfinish tungsten carbide HVOF coatings applied in accordance with AMS2447 or AMS2448 to high strength steels for applications requiring wear, heat, and corrosion resistance or dimensional restoration, such as aircraft landing gear and hydraulic actuator components. However, usage is not limited to such applications. Tungsten carbide HVOF coated surfaces for seal applications such as hydraulic actuators typically require a surface roughness of 0 to 4 μinch (0 to 0.1 μm) Ra. Tungsten carbide HVOF-coated surfaces mating with a bushing or sleeve typically require a surface finish of 4 to 8 μinch (0.1 to 0.2 μm) Ra. This process follows grinding of HVOF coatings processed in accordance with AMS2449. The intent of this specification, in addition to improving surface finish, is to change the morphology or surface characteristics in order to prolong the service life of the component.
Safety - Hazardous Materials
While the materials, methods, applications, and processes described or referenced in this specification may involve the use of hazardous materials, this specification does not address the hazards, which may be involved in such use. It is the sole responsibility of the user to ensure familiarity with the safe and proper use of any hazardous materials and to take necessary precautionary measures to ensure the health and safety of all personnel involved.