Description / Abstract:
Purpose
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.
Application
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.