Dear fellows,

I was searching for weight limit of SA-105 forgings (which is 4540 KG max). I've come to know another thing. As per Sec II Part A, SA-105, Para 1.1 Tubesheets are not in scope of SA-105 specifications. But I've used it many times previously as given in client datasheets. Anybody comment on this please.

Can we use SA-105 as a tubesheet material? If yes, please specify any reference.

Thanks in advance.

Dear Mazaffar,

I am not familiar with weight limits of SA-105, but I do know it is not supposed to be used as a tubesheet material. The problem has to do with the surface treatment of the material, ASME Section II and the SA-105 specification itself. There is some specific verbage in the spec about tubesheets and hollow forgings. You should research this and draw your own conclusions.

Dear Scott,

Thanks for reply. Weight limits are mentioned in scope of SA-105 specifications in Sec II, part A which is 4540 kg maximum.

I found a very knowledgeable discussion on this subject at one tuv bv forum. Pls. have a look visiting below link.

http://www.onetb.com/forum/materials-for-tube-sheets-t1196.html

What I learned is, we can use SA-105 as a tubesheet material if we are doing all machining processes at our workshop after purchasing a forged plate from a material manufacturer. Material manufacturer can't certify SA-105 as tubesheet material (as given in Sec II, Par A). But we can purchase a forging. Then we would perform all machining processes to convert it to tubesheet as construction code (Sec VIII, Div 1) doesn't restrict such machining processes on SA-105 forging.

Dear Mazaffar,

I also agree with you. We have also, purchased SA 105 forgings, machined it & used as Tubesheet. In fact, we have used Plates for Tubesheets where the thickness were less. Our client approved to use plate, subject to condition that all the NDT required on the forging shall be performed on the plate.

Regards

Dear all,
Please see ASME Interpertations below
*********
Interpretation: VIII-1-89-47
Subject: Section VIII, Division 1 (1986 Edition, 1987 Addenda), Tubesheets
Date Issued: December 13, 1988
File: BC88-207
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?
Reply: No.


**********
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.)

Thanks,

Mazaffar Hussain,

ASME Section II Part-A clearly states that SA-105 can not be used as tubesheet material. There is no confusion about that. It must not be used as tubesheet material.

Agreed that many companies has used SA105 as tubesheet MOC in past and some are still using. But they are unknown about the said fact. The people who know, dont use SA-105 as tubesheet MOC. If it is used and non-compliance to Code found after procurement/assembly/manufacturing then third party inspector/client/AI may creats problems.

I suggest to Scott to put a warning messange with reference of Code when SA-105 is selected as tubesheet material and also a warning messange in red color in report so all the persons who are using PV Elite can have awareness about the same.

Thanks.

Mukesh

Thanks everyone. Problem is that SA-105 tubesheets are mentioned in clients data sheets. Sometimes these datasheets are made by big EPC contractors. Moreover, I never got any comment from AI regarding this. So, I'm still confused

The reason what I heard was, the process of manufacturing, Quality control measures/technics used in manufacturing of SA105 forgings are inferior compared to SA 266 Gr.2 forgings. Mills doesn't give importance to SA105 forgings when compared with SA266 forgings

However, I havn't seen any authentic document on this.

MVK

Dear Mazaffar Hussain,

Yes many AI are not giving this comment. And also many EPC contractor write SA-105 as tubesheet material. But the fact is that it is not acceptable for tubesheet materaila as per SEC II, Part-A.

So it is always good and safe to use SA-266 in place of SA-105 as tubesheet material no matter SA-105 is mentioned in client's or consultant's datesheet.

I am sure, Warning message regarding the use of SA-105 as tubesheet material is going to appear in PV Elite and its design report soon.

Thanks.

Mukesh

All,
SA-105 is allowed as a tubesheet per UG-6(c). this was changed in the 2013 Edition and exists still in the 2015 edition.

Yes, mctitan was correct.
ASME VIII 2013 Edition rewrote UG-6 after we raised a Request of Code Interpretation to ASME committee in Dec 2011. It was about possibility of hollow shell made from SA 105N material even it was not within scope of ASME II A. Our request was supported/encouraged by a RPE in USA.

Now, UG-6 allows application of SA 105N as shell as well as tube sheet but this permission came along with controlled conditions about austenitizing heat treatment and testing on specimens.

From it, we could imagine there is lack of confident on SA 105 where heat treatment/test control were less stringent than SA 266. SA 105 is useable after control on these two aspects are improved.

Regards!