High Temperature bolts for valves

[Jamesgtx]

I have a client that made a mistake when ordering valves. They need to order high temperature valves and instead ordered standard ones. The maximum temperature the bolts would see in a fire is 1875 deg. F. Inconel 718 would be a good choice up to 1600 deg F but I am concerned that from 1600 - 1875 deg F the bolts would anneal and fail, even if the time at temperature is a very short time (say 2 - 3 minutes). Is there any other material that may work for this application?
Has anyone ever ran across a problem like this before and found a suitable solution?

 

[dcasto]

Why worry about a bolt failure when the the whole line and valves will fail.

 

[Jamesgtx]

After talking with the client they want to make sure the valves do not leak during a fire. If there is a leakage then the contents of the line will fuel the fire more and make containment much more difficult.

 

[BValve]

Hi,

Dcasto is correct, the whole valve along with piping will fail at this temperature. Your customer shall invest in proper fireproofing protection. You can find on market products specific for hydrocarbon fires which can protect the piping system for 30 minutes or more. Shall be estimated with time to stop potential fire.

Regards.

 

[OTHGWayne]

To answer your question Jamesgtx, there are several hi-temp alloys that are annealed at over 2000degF. one is Haynes HR-120. It is annealed at over 2200F There is also an HR-160 with service temps upto 2200.

Another couple of materials to consider are Incoloy 800HT, it anneals at 2100F and finally look at Hasttelloy X, that's another hi-temp alloy.

Since you seem to be looking for only short term heat resistance, that does help. These alloys can be tough to find but you should be able to find at least one of them in stock somewhere. Google them and call and discuss your application, they typically have very good tech people.

 

[dcasto]

Or just put fire protection blankets on the flanges.

 

[mrctchlr]

Also look into gasket materials. Garlock tandem spiral wound gaskets. The are specially used fire safe applications
See the attachment

 

[adrenalin]

mticheler made a good point.
If gasket materials are not suitable for fire protection than high quality bolts mean nothing.
I guess purchasing a new set of fire-safe valves might be a better choice in this case.
By the way, 1875 F is very much for estimating the valve body temperature in case of a fire.
Even in fire simulation tests performed for valves it is enough to expose the valve above 1300 F
Regards

 

[DRE111]

Looks like your client is looking for a valve that is fire tested in accordance wth API-607. This is a pretty standard offering for refinery valves. The test holds the valve in an 1800 F fire for 30 minutes at pressure. Then the valve is quenched with water and tested at 75% of the max. operating pressure. External and through seat leakage during the burn are recorded and external leakage after the cooldown.

Standard B7 and B8 bolting regularly pass this test.

It's unlikely you need special bolting material if fire tightness is all the customer wants. If the normal service temp is high then yes consider high temp bolting but for fire tightness, it's not needed. All you need is a valve that is certified to API-607.