Weldolet made from annealed bar 3

[Brandao]

Dear all, I have received an offer proposing weldolets made (on shop) from annealed bar in Incoloy B408 800HT, to be applied to a superheated steam piping (2,65 bar x 895 C). Is it acceptable?

 

[JohnBreen]

Brandao,

This is not a question that can have a universal answer. Ask yourself "to whom must it be acceptable"(?).

Most of the time it will be a matter of which design/fabricate/examine/test Code or Standard is mandated by the jurisdiction in which the system is to be installed. The local jurisdiction building Code will specify which Codes and Standards must be complied with.

Many Codes have a sections that specifies under which circumstances a "non-Standard" component may be used. It may be that to use the component the fabricator must conduct a pressure proof test and the proof test must be conducted (and documented) in compliance with a Standard for such testing. The local jurisdiction prescribed Code may also have other methods (other than proof testing a specimen) under which the "non-Standard" component may be qualified (e.g., FEA).

So, it gets down to a matter of reading the prevailing Code.

Regards, John.

 

[MJCronin]

Brandao..

The particular prevailing code is usually determined by the location of the installation.

Where will your facility be located ?

Will the steam system be built to ASME-I, ISO or other international standards ?

895C is ~ 1645F.....awfully hot for a "steam system"

Is this part of a superheater tube assembly within a boiler or part of a boiler repair ? If so, is your entire assmbly Incoloy or will there be a dissimilar weld at the base of your "weldoloet"

My opinions/observations only..

-MJC

More details

 

[Brandao]

Dear MJCronin,

Thanks for your interest, and to John Breen too, on my issue.

1) I can add that the particular code is ASME B31.3 2004 Edition, complemented by particular specs of an engineering company that, unfortunately, I can't to do mention..

2) This facility will be located in Brazil.

3) The steam system will be built to ASME-I complemented by particular specs, as quoted in 1).

4) We are treating of vapor belts at 895C.

5) It's not part of a superheater tube assembly within a boiler or part of a boiler repair. In fact, this piping will interconnect the involved equipments.

Thanks,
Brandao

 

[JohnBreen]

Hello again Brandao,

In B31.3 we do give you some latitude on the use of "non-standard" components (those not listed in Table 326.1). Please read paragraph 302.2.3 and see if you can qualify the "non-standard" components (not manufactured by methods specified in the "Standards" listed in 326.1) in the manner suggested there. The only other methods available for qualifying the components (and complying with B31.3) are the methods explained in paragraph 304.7.2 as I alluded to in my first response.

The issue of "quality control" (and methods of insuring quality) should be given appropriate attention. Also, you must be certain that your welding procedures are appropriate for the materials involved. Be sure that the pipe materials and the fitting material are welded using the appropriate wire and procedures. Also check the requirement for post weld heat treatment and give the procedure proper attention.

Regards, John.

 

[Brandao]

Hi John,
In fact, in treating of this particular conection (a forged one), the welding as well the PWHT procedures (applied just to the connection
to the run pipe) are duly ruled by adequate procedures.
At this moment, my focus is toward to the manufacturing process of this fitting from a forged annealed bar as per ASTM B408 GRADE 800HT (INCOLOY).
Unfortunately, I don't have access to MSS SP-97 (Integrally Reinforced Forged Branch Outley Fittings - Socket Welding, Threaded and Buttwelding Ends) that standardizes this kind of components. But is expected that forging process are involved on, instead of a possible machining manufacturing as we can "supose" to be adopted for this vendor.
If forged process followed by stress relief is applied, we can assure that material mill lines will lay in a paralel way. Otherwise, i.e. if machining process is applied, under the mechanical point of view, a weakening will take place.
So, my concern at this moment is restricted to this fact.
Sorry for my poor English but I'm trying to improve it.
Please tell me if my concern has some foundation.
Thanks in advance,
Brandao.

 

[LarryV]

Weldolets are required by MSS-SP-97 to be made from a forging rather than being machined from bar stock. ASME also requires pressure parts such as B16.5 flanges, B16.11 couplings and fittings, etc. to also be made only from forgings. The reason, as previously mentioned, has to do with strength issues. Machining bar stock can result in the maximum stresses on the weldolet being transverse to the rolling direction of the original bar, which will normally have a much lower strenth (i.e., the part may fail). In general, except under certain circumstances, pressure parts such as this should always be made from forged materials.

 

[Brandao]

Thanks to Larry and other colleagues,

I think you have confirmed my worries on this issue.