Can I Make my Own LWN Flanges from Bar?

[iam42]

Can I make my own 316 SS Long Weld Neck Flanges from SA-182-F316 Round Bar?

If not, why?

The main reason I want to make my own is due to the long lead time on these items!


Thanks.

 

[vesselfab]

I guess you could, as long as all the requirements of b16.5 are met and you have enough money to spend on them.

how long a delivery are you talking about and what sizes?

we get pretty quick service here with small ones in stock and large ones or long ones....like 18-20" in a few weeks.

 

[weldtek]

Better look at UG 14 and be sure you can comply

 

[Shmulik]

iam42,
No, you can't.
Please review App. 2-2 (d)(1): "Hubbed flanges may be machined from a hot rolled or forged billet or forged bar….."
App. 2-2 (d)(2): "Hubbed flanges [except as permitted at (1) above] shall not be machined from plate or bar stock material unless the material has been formed into a ring……"

Please note that you are NOT GOING TO BE ABLE to make your own 316 SS Long Weld Neck Flanges from SA-182-F316 Round Bar, simply because this type of creature does not exist!
Type 316 round bar may only be made of SA-479

 

[moltenmetal]

Take a piece of the round bar in the grade you can get, and do all the required testing on it BEFORE MACHINING. I dustily recall that there's a code case which indicates what tests are required. If I remember correctly, and there's no guarantee that I do, transverse tensile tests are required along with 100% ultrasonic flaw detection, ie. they're basically giving you little credit for the fact that the thing is a bar rather than a piece of plate. I also believe this one has been discussed before here.

 

[doct9960]

iam42,

How about making your nozzle neck from bar and attaching a standard weld neck flange on it?

You could probably use Code Case 2148-1 for the nozzle neck...

http://cstools.asme.org/csconnect/PDF/CodeCases/1074.pdf

Before you use the Code Case, you should first contact your AI and see if it is acceptable in the jurisdiction of installation.

 

[SnTMan]

Shmulik and others, I recently had some 10" round that was certfied to SA-479 and SA-182, as well as a number of foreign specs. So I suppose that any bar bought by iam42 could be mutliple certified as well.

Not that I would consider that approach, however, unless I was truly in a serious bind. Too much of the bar ends up as chips. This can't be cost competitive with a real LWN.

Regards,

Mike

 

[Shmulik]

SnTMan,
I assume that the item you describe was made as "round product" acc. to SA-182 and was additionally "down certified" to SA-479 as well. Nothing is wrong with that.
Opposite direction path is quite problematic. Please see in Sect. II Part A ; Specification SA-182 ; 1.2: "For bars and products machined directly from bar, refer to Spec. SA-479 and SA-739 for the similar grades available in those specs. Products made to this spec are limited to a max. weight of 4540 kg……."

I would most seriously doubt about the reliability of the certification for a bar (especially from stock) that appears to be "SA-182".

Just reminding you that App. 2 prohibits machining of Hubbed Flange from bar.
App. 2-2 (d)(2): "Hubbed flanges [except as permitted at (1) above] shall not be machined from plate or bar stock material unless the material has been formed into a ring……"

Best regards

 

[SnTMan]

Shmulik, my only knowledge of the product is what the paper said it was certified to. I just mentioned it as FYI.

Regards,

Mike

 

[Shmulik]

There is a strict reply at Interpretation 2-9 to ASME B16.5 1996: "Question: May pipe flanges be manufactured from bar stock and still meet the requirements of B16.5 ?
Answer: No."

 

[rhg]

Is a LWN considered a hubbed flange ??????

regards

rhg

 

[moltenmetal]

OK- you can make sections of a shell or even an entire small shell from bar if you do the right NDE on it first, but under no circumstances can you make a hubbed flange from bar? That makes no sense to me...

Perhaps if you call the LWN a designed flange and merely give it exactly the same dimensions as an ANSI LWN you can get away with it!