Welding Position Qualification Range

• My question is : the 6G welder is qualify to weld the plate for the fire water tank?

Yes, because the welder examined at 6G is qualified to work at any other position as per ASME code.

• Again, the contractor the change the welding electrodes to E-6013 contradicting the WPS and PQR; ON THIS I issued him Non conformance note, i hope am right.

No way to change the welding electrodes unless included and covered by a WPS's & PQR's.

Note. E-6013 is only recommended for structural steel works (carbon steel beam sections and atmospheric storage tanks), and in no way to be used in pressure vessels plates. For carbon steel ASTM A-516 Grade 70, used in pressure vessels, you have to use filler metal of low hydrogen family like E-7018 which need to be preheated before welding (see manufacturer recommendations and WPS's & PQR's).

Any 6G welder gets qualified to do on plate in all four positions as per ASME Sec. IX. Hence no controversy there. Being a sch 40 pipe the wall thickness also falls with the allowable limits, hence he can use the welder for 6 mm to 10 mm thick plate. You have mentioned the electrode used for pipe joint in 6G position is E 7018 . But you have not mentioned about the type of pipe used in your WPS/PQR. Is it SA 106 Gr. B? If so, even E 6013 and E 6010 could also be used for that pipe material. For Welder Performance Qualifiction (WPQ), E 7018 with F no 4 also qualifies F3, F2 & F1 and E 6013 falls under F2. UTS range for E 7018 is 550-640 MPA and 460-550 MPA for E 6013 electrode. Next, ASTM 516 Gr. 70, a Carbon Steel material has a Tensile strength of 485 MPA and generally requires use of E 7018 electrode as per technical norms. No doubt about it. Now the question is whether the fire water tank is a pressure part or statically loaded and just to hold water for fire fighting. Since the thickness is on lower side (max. of 10 mm) and if it is not a pressure part you can think of accepting the use of E 6013 (F no 2) even though E 7018 (F no 4) is appropriate. I know it could be controversial thinking, but should not create any practical problem since most of the E 6013 type electrodes have an average UTS value of 500 MPA. If required a new WPS can be written. Next point is why use a boiler quality plate for fire water tank if it is not a pressure ( please enlighten me on the pressure cycle) part. Instead, a normal A 36 or equivalent type can also work to meet your requirement. It is cost effective in all respects. In fact, the fire fighting pipe lines are welded with E 6013 type electrodes for root, filler and cap passes at many places and we have not come across any failures except for certain leakages due to poor workmanship.. Of course I have come across certain design requirements where WPS asks for GTAW or E 7018 for root welding for firefighting lines where flow of media is basically statically loaded. Sridhar

Dear sir,

ASME sec IX says

1)Per QW 461.9, if the welder passed 6G position who can able to do all position.Applications is not essential variable.So he can do fire water line also.

2)6" dia pipe of sch.40 thicckness is 7.11mm. As per para.QW251.1(b),thickness range is qualified for that welder is 14.22mm(2T).So he can do up to 14.22mm.

3)Per QW253, F number is essential variable. But E7018 and E6013 is not same F number.So you can not use E7018 WPS for welding E6013 .

If the welder is passed using F number 4,who can do the welding for F number 2(E6013-backgouging/with backing) if the company having WPS for F number 2(E6013).Otherwise they cannot proceed for welding.

The only thing they need WPS only.So you are given NCR is correct.