SA 350 AND RESTRICTIVE WET SOUR CONDITIONS 1

[francifo]

I have to solve a problem regarding the use of SA-340 steel within the more restrictive specifications for Carbon contents and others due to the moderate wet sour HS operating conditions of the vessel.
In that case not even the SA-516 60 fit, for the plates!!!

Can anyoune give me a suggestion for an alternative material?

 

[doct9960]

francifo,

Can you clarify your question? SA-340 is not a listed ASME material. SA-350 is a forging material with several grades (i.e. LF1, LF2, LF3, etc.) that classifies it as either carbon steel or low alloy steel. What particular material are you looking for? Are you looking for a carbon steel plate? What "restrictive specifications" are you referring to? Are you referring to a NACE standard?

 

[gr2vessels]

francifo,
The guiding code for wet sour service is NACE MR 0175, which allows the use of your forgings SA 350 (various grades) under some conditions, like max hardness of 22 HRC, max. sulfur content of 0.025%, carbon content less than 0.25%, equivalent carbon (long formula) max. 0.45% (refer API 0175 Annex A for details). There are listed many other carbon steel materials and the conditions of use. Depending on the application, you can request additional tests for certification, in accordance with NACE TM 0284-2003. The supplier of your forgings should be able to supply those "NACE compliant" forgings without any problem.
Also, how did you get to the conclusion that SA 516-60 is not suitable for wet sour service?
Cheers
gr2vessels

 

[francifo]

Thanks all for the replies

doct, I made a mistake, SA350 was intended

gr2, here are my customer's specs for forgings and plates, that is why I assumed SA 516 not fitting the specs.
I sent my customer a formal request to allow me to use SA 350 and SA 516-60N.
I will let you know.
Plate steel specs (max content)
C 0.18
S 0.015
Mn 1.2
P 0.020
CE 0.43 (long formula)


Forging steel specs Pipes
C 0.21 0.20
S 0.025 0.020
Mn 1.15 1.15
P 0.03 0.03
CE 0.42 (short formula) 0.37

 

[stanweld]

You should be able to obtain the materials that meet the chemistry specified without too much problem. They are fairly typical of recent (same) materials that we have purchased.

 

[SnTMan]

francifo, I'm looking at a data sheet from American Alloy Steel, Inc. (713)-462-8081 for "Tuf-37" plate, which is intended for HIC service, with restricted chemistry, etc. You should be able to find commercial plate which meets HIC requirements, it may or may not actually HIC tested.

Regards,

Mike

 

[gr2vessels]

francifo,
Your customer's spec is not out of line, except perhaps the CE for pipe, fittings and forgings is difficult to obtain and more difficult to develop a conforming PQR. The combination of very low sulphur (<0.015%) will tend to increase the hardness of parent metal and weld metal beyond any acceptable level for wet sour service. Some help to address the hardness may be available from the pre-heat levels and the interpass temperature, in addition to the PWHT.
Send your spec to steel suppliers, you should get quotes for these materials, without changing your specification (except some minor compromises)
Cheers,
gr2vessels