stelliting ball from ball valve

[samsarani]

Dear Friends
We have one order from my client to supply ON/OFF valve from size 4 up to 24 inch. Application is highly sour (H2S and CO2 and water and also a little CL). Material that costumer is ordered is A186 F6a for ball and also request for fully stellited of ball. I asked with some ball valve manufacture for fully stelliting of ball but they didn’t accept and do stelitting only contact area (areas contact between ball and seat ring). They don’t consider high corrosive media that cause SCC on ball. My questions are as follow:
1- What are manufacturer‘s limitation for apply stellite overlay on ball?
2- Is there another method instead of stelliting that cover corrosion and erosion concerns?( ENP and tungsten carbide isn’t accepted for this application)
Please note that fluid is produce in well and these valve are used in wellhead facilities. Also rating of these valve are 1500#
I ask for specialist on this subject to help me to able correct decision.
Thanks all
SAM

 

[grampi1]

Sam,

How did this get resolved? Wellheads have chokes to take the pressure drop so that other valves don't have to have full stellite. It makes no sense to ask for more than the seating area of the ball to be stellite coated. On the wellhead gate valves, only the sealing surfaces are stellite coated, why should a ball be different?