NACE MR0175 compliant stainless steel bolts/nuts

[ballvalve1337]

Hello everybody,

I have to develope a ball valve for sour gas service. Bolting should be NACE MR0175 compliant.
Temperature range -50°F up to +1000°F. What stainless steel bolt/nut material is possible?

Thanks in advace!

 

[The Obturator]

Typically ASME SA193 GrB8M Bolt / SA194 Gr8M Nut . Stainless Steel High Strength.

Per ISO-4126, only the term Safety Valve is used regardless of application or design.

 

[SJones]

What is the purpose of the bolting, and what is the valve body material?

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[ballvalve1337]

@SJones:
Purpose of the bolting is do seal body of a valve. For example please have a look at:
Klick here: Link
Here you can see bolts and nuts for body joint.

Body material should be NACE MR0175 compliant. I am thinking of A182 F316.


@The Obturator:
SA193 Gr. B8M bolt which is UNS S31600 has material Limits according NACE MR0175 Table A.2. It says: max. temp. 200°F for example. I Need 1000°F

 

[The Obturator]

Hi again. Your bolting is external and not in direct contact with H2S containing fluid. Unless the environment contains any, and then under pressure to create "particle pressure". I just looked at ISO-15156 Part 3 (NACE MR0175 (Table A2) and there is no apparent temperature limit when there is no particle pressure. See attachment. I have used this material (B8M/8M)in the past for body to bonnet valve bolting meeting NACE.

Per ISO-4126, only the term Safety Valve is used regardless of application or design.

 

[ballvalve1337]

Yes I know usually bolting is not in direct contact with H2S... but customer specified it. They argue with insulation jackets around valve and piping and if somewhere a leakage occurs. Similar like that:
Click: Link

In my honest opinion the bolting is pressure loaded. There is a stress from the sealing if valve gets pressurized. Of course usually there is no ambient pressure...

Another point I am not sure about:
Whats the heat treatment of B8M? Because MR0175/ISO 15156-3 also have notes that it shall also be solution-annealed and quenched, or annealed and thermally stabilized heat-treatment condition, no cold work and have a maximum hardness of 22 HRC.

 

[The Obturator]

OK. I understand. A bit of customer demand here. I think you may have to go right into the heat treatment options in ASME SA193 B8M. Not got it to hand to comment more.

Another option, though more expensive but available, is using Inconel 718 Bolting.

Per ISO-4126, only the term Safety Valve is used regardless of application or design.

 

[ballvalve1337]

Inconel 718 could be an option... will check that with thermal expansion between flange/bolting.
Anyway... thank you!

 

[The Obturator]

Please let me know what material you eventually select. Thanks.

Per ISO-4126, only the term Safety Valve is used regardless of application or design.

 

[SJones]

What application is the valve for? 500 deg C isn't a common temperature considered under MR0175. Irrespective of any derived partial (not 'particle') pressure of H2S, which has not been indicated in the question, the highest temperature that you can get out of N07718 without having to do some complex testing is 232 deg C (450 F in old money). Then there will be heat treatment and hardness limitations on top of that. The temperature will also stuff up 316 for the valve body too. Maybe, for the temperature consideration, you might like to direct your customer towards ISO 17945 instead.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[ballvalve1337]

The Problem is. It is not a specific Valve... it is a new product line where the exact temperature and partial pressure is unknown. Customer specified just the temperature range and MR0175 for it.
I fully agree… it maybe makes not 100% sense.
Just saw a BOM of a ball Valve manufacturer. They use Gr.660 bolting for MR0175 compliant valves temperature also 538°C.

 

[SJones]

@ballvalve1337 - you might like to enquire of the "ball Valve manufacturer" what philosophy they are applying to compliance for exposed bolting, since the temperature limit for S66286 is 66 deg C. Without an idea of H2S partial pressure and chloride concentration, you are scrabbling around in the dark.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[ballvalve1337]

After discussing again with the customer we now decided to design according NACE MR0103 not MR0175 which makes all much more easier.
Thank you all for your decision aid!