Tubesheet material SA 266 Vs SA 105 2

[Rahulvaland]

Dear all,

As per below ASME interpretation code does not allow SA 105 material as tubesheet.

Can anybody share advantages of using SA 266 material over SA 105.

There may be some fundamental behind this by ASME.

Interpretation: VIII-1-89-178

Subject: Section VIII, Division 1 (1989 Edition), SA-105
Date Issued: March 20, 1990
File: BC90-224
Question: May forged SA-105 blind flanges complying with ANSI B16.5 in pressure Classes 150
through 600 be utilized as heat exchanger tubesheets for Section VIII, Division 1 construction provided
that both flange and tubesheet calculations are performed to verify that the thickness and bolting meet the
requirement of the Code?

Reply: No. (See para. 1.1 of SA-105 for scope limitation.)

Please share your views.

Mitul patel
Static Equipment Design Engineer

Rahul Valand
Mechanical Engineering-Static

 

[stanweld]

If you already know the answer, why ask?

 

[SnTMan]

SA-266 advantage - permitted
SA-105 disadvantage - not permitted

Regards,

Mike

 

[vpl]

SnTMan - I think you just about summed it up.

Patricia Lougheed

******

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[SnTMan]

vpl

 

[Rahulvaland]

Dear Stanweld,SnTman....

Question is very much clear.If you dont know answer than dont post replies.Just read what other reply.

My question is fundamental behind it.

What makes SA 266 permitted for tubesheet material.The reasons can be manufacturing process,composition,stress values,loading condition etc.

other group members please share your views.

 

[vpl]

Rahulvaland

Yes your question is very clear. However, it is also meaningless. It doesn't really matter why SA 105 is not allowed or what the "advantages" and "disadvantages" are. Those were all considered by the Code committee back when they made the decision not to include it and there's no need to rehash it here. If you want them to reconsider, there's a method to do that, and it's not posting on an Internet forum.

Bottom line is you can't use SA 105 and call it Code material.

Patricia Lougheed

******

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[doct9960]

SA-266 advantage - no weight limit
SA-105 disadvantage - maximum weight limit of 10,000 lbs

I know of one jurisdiction that allows the use of SA-105 tubesheets...the Alberta Boilers Safety Association (ABSA). In Alberta Canada, SA-105 may be used on small heat exchangers tubesheets (ASME B16.5, NPS 24 maximum).

http://www.absa.ca/IBIndex/ib12-005.pdf

 

[metengr]

The reason why SA 105 is not permitted as tube sheet material is because the Scope statement in SA 105, 1.1 states that tube sheet and hollow cylindrical forgings are not included within the scope of SA 105. So, the code committee is following the limits of the ASTM/ASME material specification requirements. One can have forgings supplied under SA 266 for SA 105 application, but not the other way around. You have to review each specification carefully especially the grades of steel and minimum mechanical properties.

Keep in mind material specifications are generated for specific end product use and one cannot simply substitute material specifications indiscriminately.

 

[stanweld]

I know the answer. If you would like to know if SE-105 forgings were used in tube sheet construction at least prior to the Interpretation, the answer is yes. Metengr and the Interpretation have established the reasoning: it is not really metallurgical.