ASME SECTION VIII, DIVISION 1 - JOINT EFFICIENCY FOR SEAMLESS AND WELDED PIPE 1

[mech8790]

Hi Everyone!

I am wondering what factor of joint of efficiency [E] I should use in my calcs for seamless pipe and what for welded pipe (stainless steel - SA-312)? What is a difference between seamless pipe, welded pipe & seamless and welded pipe which is specified ASME section II material specification. Thanks in advance!

Regards,
Michael

 

[EdStainless]

It sort of depends, traditionally smls used 1, and all welded pipe and tube was 0.85.
The reduction applied even to welded and drawn, even if it was UTed, and so on.
But there are some specs now that for tube at least let you use multiple NDT methods on welded and cold drawn tube and then use a 1.
I am not sure about the pipe side of the issue.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[SnTMan]

Michael Kolbuc, refer to Sec II, Part D, specifically the notes for each material.

Seamless pipe / tube, E = 1.0 (for long seams). Welded pipe / tube has an 0.85 factor already applied to the allowable stresses, so E = 1.0, also for long seam.

Pipe / tube listed as Seamless & Welded has no factor applied to the allowables, they can be seen to be the same as Seamless product. Unless details of the NDE performed during pipe manufacturing are know, then it is treated more or less as roll & weld, i.e. you determine the efficiency you want and RT accordingly.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[david339933]

Depends on what the pipe is used for.
E=1 for seamless nozzle
E=0.85 for Seamless Shell
E=1.0 for Seamless Shell with Spot RT on circ(s).
Welded is the same, but use the welded stress values.
Check out UW-12(d) and (e)

 

[fleischfresser]

Michael,

I assume the code of construction is ASME VIII/1 (unfortunately not mentioned)
The key for seamless pipes is paragraph UW-12(d)
Seamless vessel sections or heads shall be considered equivalent to welded parts of the same geometry in which all Category A welds are Type No. 1. For calculations involving circumferential stress in seamless vessel sections or for thickness of seamless heads,
[ul]
[li]joint efficiency E = 1.0 when the spot radiography requirements of UW-11(a)(5)(-b)are met[/li][li]joint efficiency E = 0.85 when[/li]
- the spot radiography requirements of UW-11(a)(5)(-b) are not met or
- the Category A or B welds connecting seamless vessel sections or heads are Type No. 3, 4, 5, 6, or 8 of Table UW-12.[/ul]
This means:
[ul]
[li]if the seamless portion of the vessel is connected to other portions by other than category A or B welds a joint efficiency of 1 shall apply[/li]
[li]if the seamless portion of the vessel is connected to other portions by category A or B welds and this welds are types 1 or 2 and spot radiography requirements of UW-11(a)(5)(-b)are met a joint efficiency of 1 shall apply.[/li]
[li]if the seamless portion of the vessel is connected to other portions by category A or B welds and this welds are other types than 1 or 2 a joint efficiency of 0.85 shall apply.[/li]
[li]if the seamless portion of the vessel is connected to other portions by category A or B welds and this welds are types 1 or 2 and spot radiography requirements of UW-11(a)(5)(-b)are not met a joint efficiency of 0.85 shall apply.[/li]
[/ul]

For welded pipes endnote 8 of UG-8 have to considered. Only welded pipes without filler metal added are considered as material. For these materials in the allowable stresses of ASME II-D a quality factor of 0.85 is included (see Table 1-100 Criteria for Establishing Allowable Stress Values for Tables 1A and 1B).

Regards - Juergen

 

[mech8790]

Thanks guys for quick respond!

It is ASME Section VIII Division 1, I mentioned it in this thread title. Fleischfresser, thanks for elaborating this problem! I consider this thread to be closed.

Regards,
MIchal