Flange, bolting and nuts

[kissjxp]

Can SA350 LF2-CL1 or SA350 LF3 flanges be used at high temperature? I am working on a vessel with a Design Temperature of 300degC. MDMT is -46C. Occasionally, the vessel will be exposed to 490degC (20Hours/Year). SA350 LF2-CL1 or SA350 LF3 can be used at low temperature. How about their high temperature properties?

Can anyone recommend the bolts and nuts materials for the above mentioned service?

Thanks.

 

[kissjxp]

By the way, the vessel material is impact tested ASTM 516 Gr. 65

 

[SnTMan]

kissjxp, it would be helpful to know a little more about what you're doing, i.e code of construction, custom flanges or standard, etc.

ASME Sec II, Part D, lists SA-350 LF3 with a max temp of 650 F., SA-350 LF2 at 1000 F., although it is deep into the creep range and allowables are pretty low.

SA-193-B16 bolting might be useful as it has pretty good allowables to 950 F.

If you can taks a look at Sec II, Part D, the allowables listed will answer most of your questions I expect.

Regards,

Mike

 

[unclesyd]

Is the equipment going to be exposed to the 490C under normal operating conditions?

One part of our process operates at 285C @ 1800 psig and is cleaned by Pyrolysis where it sees 900F for several hours during each cleaning cycle. For this system we use mainly use SA193 B7 studs with the standard 2H nuts. The pipe and flanges are SA 105 and SA 106.

 

[kissjxp]

SnTMan, unclesyd

Thanks.

The equipment is not going to be exposed to 490DegC under normal operating conditions.

Can the internal bolting of SA193 B16 or B7 be used at -46DegC?

 

[SnTMan]

kissjxp, for Sec VIII, Div 1 B7 up to 2 1/2" is exempted to -55 F., B16 only to -20 F. If this is not your code of construction, these exemptions may not apply.

Regards,

Mike