Field welding sch. 40 2" and below

[engr2GW]

Hi,

I was told that if thin wall pipes like sch. 40 and less if stick welded only, they may not be able to pass x-ray, and the other welding process like MIG, etc may not be easy in the field where stick welding is popular because of equipment type.
Is there any variable that can change like: Choice of electrode that can make it possible and better to stick weld thin pipes in the field?

Thank you.

 

[metengr]

What is the pipe material? Service conditions? Typically, for low pressure applications, an open root butt weld made using the SMAW process can be done by experienced welders.

 

[engr2GW]

Thanks,

Pipe material coule be: A106 A, B. x-42, x-52,... BUT MOSTLY A106 GRADE B.

 

[stanweld]

Socket welds are most common for welding 2" and under carbon steel pipe, in which case E7018 electrodes are commonly used. Assumming that full penetration groove welds are required with RT requirements, GTAW is recommended. Highly skilled SMAW welders using E6010 electrodes could also make full penetration groove welds on the larger diameters (1" to 2") and meet RT requirements.

 

[Duwe6]

If going the SMAW route, it is 'safer' to limit the 6010 to root only, as it tends to have a significant ammount of porosity. Follow up with a X-ray grade of 7018 [most folks, including me, prefer "AtomArc" for X-ray work]. Also, try to use UT for your volumetric testing, instead of RT. Since UT looks at the weld in 3 dimensions, it can see how scattered the porosity is. It is common to have a pipeweld that is rejectable on RT for porosity, and acceptable using UT.

Concurr that GTAW is a superb process. Somewhat slower than SMAW. *Not* a lot slower. [this is counter to most texts, but has been my experience in the past 32 years].

GMAW is not really a field process, unless the diameter gets above 12" or so. Still not much faster than SMAW, due to set-up time and the requirement for draft shielding.