Valve Orifice Erosion - resistant material?
Valve Orifice Erosion - resistant material?
(OP)
A difficult erosion problem is handling a 10 kpsi pressure drop across very small (.005 in.) orifices created by sliding gate valve seats. Tungsten carbide is quickly eroded. The candidate material must slide at low speed as the valve opens with 20 kpsi contact stress without galling. The fluid is water or alchohol. Sealing surfaces are lapped flat.





RE: Valve Orifice Erosion - resistant material?
What type WC are you using?
What form is the corrosion, IE wire drawing etc.
RE: Valve Orifice Erosion - resistant material?
RE: Valve Orifice Erosion - resistant material?
Pressure can load the seal ring to the gate at 20,000 psi contact stress while dropping 10,000 psi through an orifice created by the valve position to control flow.
I have tried WC with 6% nickel binder and 1.3 micron grain size and also 5% cobalt binder and .5 micron grain size. Both WC part sets showed significant loss of binder (>.005 in.) at the point of highest velocity flow after 50 gallons total flow of tap water.
This is erosion of the binder as grains can be seen unsupported by the binder at the point of high flow velocity.
I have tried solid silicon carbide but hoop stress and difficult geometery causing stress risers led to fracture.
Thanks for your interest!
RE: Valve Orifice Erosion - resistant material?
RE: Valve Orifice Erosion - resistant material?
RE: Valve Orifice Erosion - resistant material?
I know of an application that is taking a 6500 psi drop across this material with apparently no problems.
The diamond material just looks interesting. My experience has been with diamond guides in spinning steel. Have seen diamond nozzles/jets in UHPW systems.
http://www.cerbide.com/s.nl/sc.2/category.16/.f
http://www.novatekonline.com
RE: Valve Orifice Erosion - resistant material?
What else have you tried?
First thought is a hot pressed SiN.
Diamond should also work. I have used diamond wire draw dies and I have seen them used in some extreem extrusion applications.
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Corrosion, every where, all the time.
Manage it or it will manage you.
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Valve Orifice Erosion - resistant material?
If the ceramics route proves unfruitful, consider the metals that work in cavation applications, like the Stellite series of cobalt based alloys.
RE: Valve Orifice Erosion - resistant material?
The other thought is to look into TiCN coating an ultra hard tool steel. This coating is CVD applied and diffused into the metal (it reacts with the C in the metal). Maybe use CPM REX T15 or 121 as a substrate.
= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Valve Orifice Erosion - resistant material?