Qualifying of the welder using GMAW process

[Toperek]

Hi,
I have question to qualifying welder under Section IX using GMAW on 14mm thck plate SA-516 gr.60. The whole coupon is GMAW welded but root pass is done to short-circuit (ca. 2mm) and rest with globular transfer mode. According to requirements Section IX, QW-404.32 the qualified thickness is restricted to 1,1 times deposited weld metal thickness - which implies that the rest thickness is 12mm and can not give unlimited "t" but only 24mm.
What more: the resulting WPQ shall be issued dually or at least divided into short-circuit part( "t" <= 2,2mm )and globular/spray/pulsating part ( "t" <= 24mm ). Strange but this way of thinking leads us to conclusion that we have new welding process ( called for example GMAW-S like in AWS ) which is not clearly defined by Section IX (actually we have (excluded automatic and maschine welding) only OFW, SMAW, SAW, GMAW/FCAW and PAW). Without this division between those two processes (type of processes) I will have unlimited thickness qualified, without backing for second one - what makes considerable difference. Where is the logic of this restriction whenn 99 joints welded with GMAW must have be done for years with root pass(ess)welded short circuited, wheras and at the same time Code treats FCAW like GMAW. Or am I wrong? Please someone with more experience in ASME to correct me on this. Thanks. Andrzej

 

[Kiwi2671]

Andrzej,
Short circuit and globular are both modes of transfer in the GMAW process.
Your deposited weld metal with the GMAW process is 14 mm which means you are qualified to unlimited thickness.
QW 452.1 Note 1 only requires individual deposited weld metal thicknesses to be recorded and applied if you have more than one welder, more than one process or more than one filler metal F-number - none of these are applicable to your situation.
You are however limited by QW 404.32 which means GMAW (short circuit) may be no more than 1.1 times the thickness of weld metal deposited in the test coupon.
Hope that helps,
Regards,
Kiwi

 

[Fizza453]

I would say QW-452.1(b) as welder can deposit weld with short. circ mode upto 2.2 mm and with other mode of transfer up to 24 mm.
There is very important point,you cannot qualify the welder by using volumetric NDE because of short circuiting mode of transfer, see second sentence of QW-304.

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN