Fabricate a tubesheet (3000 mm dia x 70 mm thk) from SA240GR.316 Plate material 2

[OMIO100]

Dear Friend

I have to fabricate a tubesheet (3000 mm dia x 70 mm thk) from SA240GR.316 Plate material.

Any one can help me to understand

1)the permissible minimum plate width ( as per code)?

2) as well code permissible welded Tube-sheet from plate?

3) NDT & Testing requirement as per code?

Thank you

Regards

Omio

 

[SnTMan]

OMIO100, which code?

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[OMIO100]

As ASME sec VIII or TEMA

 

[SnTMan]

OMIO100, ASME Sec VIII is a CODE, it usually has the force of law. TEMA is a STANDARD, compliance is usually a voluntary or contractural matter.

OK, so if you are under Sec VIII, Div 1: From your questions 1) & 2) it seems you need to fabricate a tubesheet of two or more pieces with a weld seam. Both Sec VIII, Div 1 and TEMA are silent on this. It is not prohibited, therefore it is permitted.

Your question 3), there is no variable in Part UHX representing joint efficiency within the tubesheet itself, it is implicitly equal to 1. Therefore, full x-ray would be required. As well, UT and PT would likely be advisable.

If I had any choice at all, I would not place a weld seam in the tubefield, as I would not wish to drill tube holes thru weld metal, which generally machines less well than the base metal.

if you are under Sec VIII, Div 2 the forgoing may or may not be accurate, I am not familiar with it.

BTW, you say 3000 mm dia. In the US, plate is generally available in 120 in (3048 mm) widths. This width should easily yield a 3000 mm finished diameter.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[MJCronin]

SnTman gives good practical advice ...

Tube holes are, of course, gang drilled after the plates for the tubesheet are welded and inspected.

With a massive piece and a diameter of 3000 mm, you are at the limits of the machinery produced for this kind of drilling.

Are you sure that you can perform this drilling operation with a tubesheet of this size ???

Perhaps you can share with us the design drawings for this massive HX ???

MJCronin
Sr. Process Engineer

 

[OMIO100]

SnTMan (Mechanical )/Mike

Thanks for sharing your valuable advice;
Yes i am considering only one weld joint at around 2/3 of T/Sheet dia ;
as well avoiding drilling on weld joint ( scope is there as per Tube layout );
It is under ASME Sec.VIII div 1 only .

Thanks

Omio

 

[SnTMan]

OMIO100, well good luck with it. Inspect, inspect, inspect.

I'd guess that due to warpage, you may need up to 25 mm extra thickness for machining allowance, if tubesheet is to be flat prior to drilling.

Regards,

Mike



The problem with sloppy work is that the supply FAR EXCEEDS the demand