B31.3 332.4.2 Cold bending and forming

[xgiorg]

Hello,

1. I would like to know how to apply (for the heat treatment): "This requirement may be waived if it can be demostrated that the selection of pipe ..... ..... the most severely strained material retains at least 10% elongation".

I mean how to demostrate this point? Someone may show an example?

2. Also, when they wrote: "The max calculated fiber elongation after bending or forming exceeds 50% of specified basic minimum elongation..." means that I have to calculate a half the xx% elongation of the tube. But where I can find this values? I took a basic elong of 35% for a A-192 tube.

 

[EdStainless]

For the second one. Look in the material spec. Let's suppose that the minimum specified elongation is 30%. Now analyze the bend. If the metal was stretched less than 15% you are OK.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[metengr]

xgiorg;
This is a confusing post from the start, period. You take small excerpts from B31.1 332.4.2 and ask for code interpretations. First, what is the material for cold forming and bending, does it fall under one of the P No 1-6 materials in (a)? Second, you reference ASME B31.3, is this the code of construction you are working under?

Please provide more background information as to the material you are working with and what type of bending and forming operations. If you need to calculate fiber elongation from forming and bending there are formula's in ASME Section VIII, Div 1 UCS-79 for cylinders or in Section I PG-19 for tube flares, swages, upsets and bends.

 

[xgiorg]

Sorry for the delay. The material used is SA-192 (P-Nº 1) and the code of construction is ASME I. The item is a bend, made with a cold formed tube (51mm x 5mm). I saw the Section I PG-19 but it's for austenitic materials.
The bends have a radius (center fiber) of 60mm, 160mm and 260mm. Also it is used for the bends other material: SA-213 T22. Someone knows how may I know if I have to make a heat treatment for SA-192 and SA-213 T22 with asmeI?

 

[metengr]

There is no supplemental thermal treatment requirements for cold bending P-No 1, 3, 4 and 5A materials. The use of hot bending may be required to assure minimum wall thickness and ovality concerns, but that is it.

 

[xgiorg]

Why for this materials there is no heat treatment needed? (because in asme I is not described?). Should I use the B31-3 to complete this info(normally it's allowable to use diferents codes)?
Thanks metengr.

 

[xgiorg]

I saw in PW-39.2.1 that the pipe and tube to headers must be post weld heat treated, then is this the only point in the equipment to treat?

 

[stanweld]

The service conditions for B31.3 are quite different from B31.1 and ASME I. You do not need to employ the added B31.3 requirements for pipe systems subject to ASME I or B31.1, although you could if you so choose.

 

[xgiorg]

Thanks stanweld, I suppose that applying ASME I in this case means decide to make the heat treatment for the bends, through my consideration.

 

[stanweld]

Assuming that the design Code is ASME I, you can use ASME I (no restrictions other than good engineering judgement). For bends subject to ASME B31.1, section 129.3 applies.