Seamless pipe and welded pipe query..!! 1

[vpkhati]

Dear All,

Can anyone tell me the size limitation upto which we can go for seamless pipe or welded pipe.

Specification SA 106, SA 312, SA 790 calls for seamless pipe, but above NPS 12 our supplier is giving welded pipes?

What should be the criteria of acceptance for welded pipes.?

Are there any limitation on the size for the supply of seamless pipes..?

Can small size pipe like NPS 3 to NPS 8 be supplied in welded construction.?

 

[SnTMan]

vpkhati, SA-312 & SA-790 may be seamless or welded. SA-106 seamless only. Welded pipe is very common in alloy.

Acceptance criteria, first, what does the design require, as allowables are different between the two. Physically the acceptance is per the relevant specification.

I doubt you are going to find any seamless pipe over 24", and any size may be welded. Each pipe spec references the applicable dimensional schedule.

I nearly always design alloy pipe as welded, that way I don't care which they buy.

Regards,

Mike

 

[metengr]

For time independent service conditions, welded or seamless is acceptable.

For time dependent service conditions, welded piping has its issues because of concerns for creep damage along the weld seam, which is the reason for weld reduction factors in the Code. More in-situ inspections are required for seam welded piping.

 

[rmw]

SnTMan,

If you know where the "gittin place" is for A106 in sizes 12" - 24", please post back. My fabricator needs to know.

Thanks,

rmw

 

[Fizza453]

vpkhati,

See also footnote 3 to UG-8 if pipe is being used in Section VIII-1 construction.
As metengr noted, for the components operating in creep range, Section I and B31.1 have provided the weld strength reduction factor that is a function of material and operating temperature.

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[SnTMan]

rmw, they tell me we buy a lot of this stuff from Lee Supply, Tulsa OK, 918-587-8181, Denny.

Where is your fabricator?

 

[rmw]

SnTMan,

Some domestic, Texas, Florida, and some in all other parts of the world. Interestingly, some of those here in the Houston area seem to have as much difficulty finding A 106 pipe in sizes greater than ~10" as fabricators offshore, especially in schedules lighter than std wall.

I'll call him tomorrow.

rmw

 

[GenB]

vpkhati welded vs seamless
there are 2 different pipes and the use is for any job,
Some Codes prohibit the use of welded on some construction types or uses.
limitations can be 1-customer specifications 2-price 3-commercially available 4-if in the US you face all 3 if your customer wants domestic, face it you will pay more and you may have hard time getting it.

 

[vpkhati]

Dear all,

thank you very much for your valuable reply.

... Normallly we also design above 12" pipe as welded construction... so here the allowble strees factore criteria comes into the picture...

But if we are purchasing a pipe from the stockist. then he need to perform the 100% radiography on the weld seam. and certify the pipe.

right..?

 

[GenB]

Is this ASME VIII-1 work? you mention RT1 and certify the pipe, You mean your own certification for your own satisfaction right?

Welded/ERW I would worry about stress on the complete so PWHT and overall stress relief comes into consideration.

 

[SnTMan]

vpkhati, you should really see the relevant pipe spec and PV Code. Generally if welded without filler metal, RT is not required and joint efficiency is equal to 1. If welded with filler metal a joint efficiency must be considered.

rmw, I too have found wall lighter than standard to be hard or impossible to get in SA-106B, and re-designed a HX a while back after release when purchasing could not find, I could not find, nobody could find 8 ft of 10" or 12" SCH 30 for the shell.

If you can't get it Houston, I'd say you can't get it

Good luck.

Mike

 

[vesselfab]

try pipe distributors in houston. mostly domestic a-106-b from uss.

also texas pipe

 

[unclesyd]

I definately would give American Pipe a call. They have one of the best stockist in the US.

htp://

http://www.amerpipe.com/products/seamless-pipe/carbon/a106.php

Do you need thinner wall than Sch 10?

 

[TJOrlowski]

Dixie Pipe & Tioga Pipe Supply are also good sources for carbon and alloy pipe. We've had good luck with finding the oddballs through Tioga.

SnTMan, were the 10 & 12" Sch.30 not in stock, or did everyone want to sell you the whole single (or double) random?

-TJ Orlowski