Definition of Tubular Product - Section III 1

[wesman33]

Hello all.

I am seeking discussion on the ASME definition of what a "tubular product" is, and applicable examination requirements.

Let's say a certificate holder buys a forged rod, then bores a hole down the center of the rod. Is this a tube? Do the material inspection requirements for tubular products apply, or only the requirements for a forging? (I realize that the machining operations introduce additional inspection requirements - I am only asking about the material requirements in NB-2000)

I have had some people opine that it is a tube, because it "looks" like and is functionally equvalent to a tube.

Other people have stated that the product specification dicates what inspection requirements apply - since this part was ordered as a forging, only the forging rules apply. If the part had been ordered to a tube / pipe spec, then the tubular product rules would apply.

I have an opinion, but would like to hear any arguments for either case.

Thanks!

 

[codeeng]

You'll need to look at you material spec for forgings. For example in SA105, Section 4.4 states "...cylindrically shaped parts may be machined from forged bar provided that the axial length of the part is approximately parallel to the metal flow lines of the stock...". If this is the case then you would follow the requirements of a forging.

 

[EdStainless]

If you are using it as a tube (pipe) then both sets of rules may apply.

= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[GenB]

Even shells of a vessel can be made from forgings/forged bar, so you can make tubes from forgings; machined forgings will not have any mat undertol as pipe so you on;ly calc your Corr allowances. Tests: you will have to comply with the required tests for forgings. you mnay not need any other tests but calculation of the walls as say the B31.1 calcs for any pipe ot nozzle/forging does.
er

 

[QAFitz]

Just a couple of quick points-to-ponder
- Ask the ANI (get it in writing);
- If the finished material spec nor any of the references
in the finished material spec don't address what your
after then ask yourself what realy applies;
- ASTM has a compilation of terms and definitions;
- There are various Code interpretations out there but
use caution because they are not part of the Code;
- Ask the customer (get it in writing);

 

[unclesyd]

We have never had any trouble using tubing and vessels made from solid bar. We had one process that all the vessels (10" od x 16" long designed for 2500 psig @ 700° F ) were machined from solid bar.

We used trepanning regularly to make high pressure vessels.

http://www.clarkwheeler.com/trepanning.htm

 

[lostsailor]

wesman33
I concur with all of the above posts, in a general sense. The problem with generalities is that they often tend to fall apart when applied in a specific manner. QAFitz' advice regarding the ANI and customer is right on point, I would also throw the PE signing the Design Report into the mix. What you suggest is not out of the ordinary, be sure to mind your P's and Q's.

In your specific instance, since the product was ordered as a forging, it must meet the material specification for the forging, with appropriate certifications. In using the forging as raw stock for a tubular product, you must then meet the requirements of the tube material specification, and supply appropriate documentation certifying the material as such.

Anyhow, those are the basics. The actual supply chain can get a bit more complex depending on who holds what certifications, scopes, etc..

Regards,
RLS

 

[wesman33]

Thanks to all who responded. I agree that QAFitz' comment regarding ANI and cutomer concurrance, and "in writing" are good advice. Therein lies the hiccup.

We actually have a difference of opinion with our customer. (First time ever! Honest!)

Some specifics:

We are providing a welded vessel. We have fabricated a nozzle for this vessel from a piece of forged bar. All of our documentation both internally and from our material supplier use the forged bar material specification.

Our customer's contention is that since the part now "looks like" a tube, NB2145(d) applies, and we must do the additional examinations required for tubing.

My understanding of the Code is that NB-2000 governs material supply, not machined parts / finished vessels. (So - if I wanted to sell you a tube, but all I have is a piece of SB-166 forged bar, I can use it, but must do the additional inspections before I can certify and sell it to you as a SB-167 tube.)

I think an authoritative definition of when a tube is a tube would help both parties reach an understanding. So I guess my original question could be better stated as:

"Is product form dictated by the material specification, by general shape, or by intended function?"

Thanks again for your time.

 

[lostsailor]

wesman33,
Question:"Is product form dictated by the material specification, by general shape, or by intended function?"
Answer:"It depends"

How is this nozzle referenced in the design specification/drawing/design report/data report?

You may want to post this question in the nuclear forum.

Regards,
RLS