Low Temperature Bolts For H2S Service

[SJones]

Has anyone experience of getting A320 L7M bolts to achieve the specified minimum toughness values at -120 deg C?

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[Cockroach]

I believe these are rated to -40C, not -120C which is a cryogenic application.

Alternatives NACE material for the stud would be ASTM A193 L7M with the ASTM A194 2HM nut.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[stanweld]

Whereas the impact test temperature for L7M is -100F (-73 C), your chances of finding L7M meeting the required energy absorbed values at -150C are nil based on old impact test data that I've seen.

 

[dcasto]

Why would the bolts be in H2S service, are they inside the piping and vessels?

 

[SJones]

No - they are externally located but are still to meet the requirements of ISO 15156.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[X60]

SS304L is commonly used in Cryogenis Environments, also you could have them coated in PTFE or Xylan/Xylar. Don't know if this is any help?

 

[SJones]

We're going the ISO 10423 route and trying ASTM A453 Gr660 Class D. Fingers crossed on the Charpy tests.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/