X52 / API 5L Seamless Pipe Fitting Equivalent

[engpes]

I am using seamless joing of X52/API 5L piping and I am trying to determine what material grade to use for the tees and 90s.

My question is this:

1.) What material grade can I use for the fittings (90's and tee's) so that my X52/5L piping is the "weakest link" and the governing element?

I know that ususally B31.3 says that all standard fittings are rated for at least the equivilent pipe rating. I would ususally use SA234WPB, but this has a lower yield strength than X52 / API 5L.

I am dealing with sizes ranging from 4" to 12" nominal diameter (sch 80).

Thank you very much in advance!

 

[stanweld]

There are ASTM A-381 Y52 fittings. But do some calculations, you may be able to find that WPC or WPB fittings will fit your purpose.

 

[surekhaajay]

I have used SA234WPB, for API 5L, X60 upto pipe 42" diameter (94 barg pressure) and API 5L, X42 upto pipe 24" diameter (39.5 barg pressure).

 

[LittleInch]

I normally use A694 grade FXX, where XX is the material grade equivalent for pipe, in your case 52.

I am somewhat curious though as to why you're using 5L grade X52, but designing it to B31.3 as you only get 10% more stress value than grade B?? Also all the fittings tend to be much more expensive than standard A 105. It doesn't normally make sense to use pipeline materials in a piping code. You can normally design piping within a plant to pipeline codes (b 31.4, B 31.8) if you have to or if you have lots of meters of pipe, but ususally the cost of the fittings (elbows, flanges etc) to match the X range of line pipe is much higher than any marginal saving on pipe material

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way