Ball valve

[sputnik75]

Dear all,

I’m dealing with a Ball Valve that has to face a harsh wearing environment. I have to choose between tungsten carbide coating and a 300-mm solid tungsten carbide ball.
Is it possible to manufacture such a ball in solid tungsten carbide? What is the advantage of a solid ball against a coated one? Is there any technical topic about?

Thanks to any reply

 

[anand25111987]

No one can manufacture a solid TC valve. TC is available in a powdered form which can be only coated over ball profile using high velocity fuel process.

 

[gerhardl]

Whatis a harsh wearing environment? If temperature and pressure allows you can try valvetypes with longer standing time without service for abrasive media.

For strongly abrasive media you could try quetch valves (whole range of different linings available) or v- port ball-shell valves (full opening), eccentric shut-down and ceramic lining.

Example of the last type:

http://www.metso.com/products/ball-valves1/metsos-neles-series-e-ceramic-ball-valve/

 

[bcd]

For a solid ball, you are more than likely meaning Stellite 6B. This is Cobalt & Chrome based material that is very common when a hard, wear resistant material is needed. It is available in bar stock and a solid ball can be machined from it.

 

[GianPietro]

Cemented carbide balls can be manufactured by standard PM process. Nonetheless, if the passing hole diameter is large, valve producers prefer to choose the coating solution, because of the weight and the cost of the valve.
By the way, when high wear resistance is needed, solid cemented carbide parts ensure better performance than coated steel.
To manufacture large size balls, large equipments (presses, lathes, mills and ovens) are needed. For large balls isostatic pressing is preferred.
If you need, try

http://www.omcd.it

Gian Pietro De Gaudenzi

http://www.omcd.it

 

[nosivadbor]

Hello sputnik75,

It is not impossible to manufacture a 300MM ball valve from Solid tungsten carbide, but it would be very expensive. Most people choose a coating, because you will need to replace the value after a certain amount of wear, so as long as your coating thickness is beyond your allowable wear tolerance, you should be good.

Depending on the media and conditions you can use a Tungsten Carbide based coating or Cobalt / Nickle (Stellite) based coating. Depending on the abrasive/corrosive/erosive/temperature and the inter-relationship between those will dictate the most appropriate coating.

I work for Kennametal Inc. and we offer multiple technologies to apply coatings of tungsten carbide and Stellite to ball valves, as well as solid tungsten carbide, if that's what you really want. If you need advice you can contact me offline or we can discuss here.

Best Regards,
Rob