Tungsten Carbide coating 2

[pipexp]

Dear Experts,
What should be coating thickness of Tungsten Carbide on metal seated ball Valve? In one of TOTAL specification I have noticed the coating thickness to be 400 microns. But many of the vendors in the field informs that 400micron is not a good option. Most optimum value shloud be in the range of 200microns to 350 microns.

Can any of the experts advice me in this regards.

Thanks & Regards

 

[gerhardl]

I cannot comment directly, but an interesting question is how the thickness is defined and measured from producer to producer microscopically. Both the original surface (binding between the materials) and the layer of tungsten carbide's outer surface will have 'valleys and mountains'. Equal and equally measured for all? Equal quality? Standard? Methode of fabricaation? Procedures?

 

[thost]

I mostly work with Statoil specs. The requirements for this TCC spec is:
The coating shall be in the range 0.15 to 0.25 mm after grinding and lapping. All coated parts shall have maximum roughness of Ra = 0.15 µm.
The spec is not referring to any quality standard else than for bonding test.
Se attached file for the Statoil TCC requirements.

 

[valvit]

I concur. In my opinion, 400 micron is excessive. More is not always better. Many manufacturer's standard is 150 micron after final grinding.

 

[PAN]

Please refer to thread408-289823 .

 

[pipexp]

Dear Experts,

Thanks for your valuable input on the subject which helps in firming up the requirements. Based on the above, I consider 150 to 250 micron is a good choice considering availiability in the market, production time of the valve. As I understand 400 micron may be a bit over specified unless situation demands.

Thanks once again,

Regards.

 

[ballvalve02]

Please upload TOTAL specification