pipe bending

[dahar]

What formula is used to predict or calculate pipe wall thinning due to bending?

 

[pigmeat]

ASME B31.3 Para 304.2.1 - Pipe Bends - gives the formulae for working out the minimum required thickness of a bend after bending.

 

[tommac]

If you are working with B31.1, I would suggest that you look at the 2004 edition (para 102.4.5) because the criteria for the minimum required thickness of a bend after bending has been revised.

 

[SnTMan]

TEMA (Tubular Exchanger Manufaturers Assn) has something similiar. It is based on the simple geometry of the situation. That is, the wall thinning is inversely related to bend radius.

t0 = t1(1+do/4R)

t0 = original wall thk
t1 = "minimum required" wall thk
do = OD
R = centerline bend rad.

You can solve this for t1 and "predict" the final thickness based on OD, R and t0.

You may be able to use this, it depends on whether you are working to some Code or standard, or whether you need a great deal of accuracy (if so, I wouldn't!).

Hope this is useful.