thread repair on valve body casting
thread repair on valve body casting
(OP)
Hallo,
I have a valve body (Material ASTM A217-WC6) which has got 10 x 1" threads to fix the bonnet on the top. However during manufacturing, the hole for the threads were drilled too deep and it entered the body gallery.
My question: How can I close the hole and at the same time save the casting and the thread? The valve is designed to ASME.
thanks for your quick response.
I have a valve body (Material ASTM A217-WC6) which has got 10 x 1" threads to fix the bonnet on the top. However during manufacturing, the hole for the threads were drilled too deep and it entered the body gallery.
My question: How can I close the hole and at the same time save the casting and the thread? The valve is designed to ASME.
thanks for your quick response.





RE: thread repair on valve body casting
My focus: Alloy Valves in duplex, super duplex, alloy 20, monel, inconel, incoloy, hastelloy, titanium, 904L, zirconium and uranus Valve Stockist Valvulas
RE: thread repair on valve body casting
RE: thread repair on valve body casting
prognosis: Lead or Lag
RE: thread repair on valve body casting
Petrotrim Services
www.petrotrim.com
RE: thread repair on valve body casting
RE: thread repair on valve body casting
You have gotten advice relative to returning the valve to the manufacturer for replacement and you have gotten advice on self repair.
Now lets say you do go ahead and repair the valve and put it into service. Later this valve fails for some reason even unrelated to the repair. Three maintenance workers were killed and another three were seriously injured. Injured enough that two of them will never work again.
The post accident investigation uncovers that the valve which failed was modified in the field prior to installation. The investigation further uncovers that this repair was not done by the original manufacturer or with their approval. This discovery of an unauthorized repair therefore invalidates the original manufacturers warranty on the valve and throws ALL of the legal and financial responsibility for the deaths and injuries onto your company and by association onto you and the other people who did an unauthorized repair.
Could this happen? Yes! Would this happen? Do you really want to chance it?
With that said, I repeat my original recommendation; Send it back to the manufacturer and tell them to replace it.
prognosis: Lead or Lag
RE: thread repair on valve body casting
thank you for your advice. This is a water/steam valve with operating temp at 300°C. This valve was in service for 6 years now. End user only recentyl noticed that steam had been comming out of 2 of the 10 holes.
As this valve has to go back into service, we are trying to make a quick fix.
@jwhit: the inside of the valve body can be accessed thru a 250mm diameter hole. I am not quite sure whether this is sufficient to access the damaged holes. But according to ASME Section II "The casting shall not be peened, plugged or impregnated to stop leaks" this means that the weld repair you suggested is not applicable right?
@pennpiper: I understand the your concerns regarding the repair. I would however would like to know the options I have for repair before sending it to the foundry where this valve was purchased.
RE: thread repair on valve body casting
RE: thread repair on valve body casting
This must be worse than even Pennpiper thought! I am sure you have already decided not under any circumstances to put the valve back without certified repairs and the factorys' guarantee, or a completly new correctly certified valve.
Chances are that even when filled with bolts and screwed down with nuts, you might get, or already have had, cavitation conditions through the threaded holes. Recently found leakages indicates worsening conditions over time.
300 deg centigrade equals between about 80 and 90 bars in my steamtable, a steampressure giving reason to be careful.