Pipe Fittings - Manufacture Method

[RandomAxe]

Aside from project specification what would govern the manufacuring technique used for a pipe fitting (ASME B16.9)? I generally work with pipelines that require pigging and as such pulled/induction bends are generally specified (3D or 5D). However, in manifolds or spools where pigging isnt required it is my understanding that buying 'off the shelf' B16.9 fittings for bends is significantly cheaper than pulled bends. From looking at B16.9 and the trouvay and cauvin handbook, the long radius elbows are 1.5d and come in a range of schedules and in carbon steel or stainless. I can see no real mention of the manufacturing process required though, and see mention of seamless, welded or forged. What are the requirements by codes and what are pro's/con's associated with each? Would a welded fitting have more inspection requirements etc?

 

[racookpe1978]

A "pulled bend" ?

 

[pennpiper]

racookpe1978,
Look here:

https://www.google.com/search?q=pip...=B4oAJ027zdSGwM:;HyT8NGJyXlreOM;http%3A%2F%2F

http://www.hossfeldbender.com%2Fsto...ling%2Fbasic-pipe-eye-bolts-rings.php;530;292

You will see an example of a machine that is making a "pulled bend".

prognosis: Lead or Lag

 

[fegenbush]

ASME B16.9 Seamless fittings are formed from ASME SA106 Grade B pipe. The title of the B16.9 standard dictates how these are formed, Wrought. This process is similar to that of your "pulled" fittings of larger bend diameter.

Welded fittings are formed from plate (ASME SA515 Grade 70) in a different manner, but still wrought.

Reference: Crane Catalog No. 61 (1961 Edition)

 

[XL83NL]

ASME B16.9 Seamless fittings are formed from ASME SA106 Grade B pipe.

Obviously, when you have stainless steel B16.9 fittings, this doesn't hold.

 

[fegenbush]

XL83NL,

You are correct. Please add the statement "for carbon steel fittings" to my previous post.