Welding without filler metal, A_N.¦?

[bagnamento]

Hi everybody,
a colleague of mine asked me if, when A_N.° is an essential variable for welding procedure qualification and no filler metal is used, the molten base metal should be considered as weld metal and its chemical composition be determined in order to determine A_N.°

I believe that A_N.° is not a concern if no filler metal is used.

What do you guys think?

 

[gtaw]

I changed my reply and simply went to Section IX of the ASME B&PV Code. Why push the rock uphill when you can have a bulldozer do it for you.

What welding process are you using or considering?

I looked at GTAW and Laser. GTAW lists paragraph QW-404.14 that states the addition of or the deletion of filler metal is an essential variable. QW-404-.5 lists A number as an essential variable.

Under laser welding paragraph QW-404.14 (addition of deletion of filler metal)is again listed as an essential variable, but QW-404.5 (A number) is not listed.

Anytime the base metal is melted to form a weld, it has an opportunity to alter the chemistry by oxidation of the more easily oxidized elements and by other chemical reactions taking place in the molten pool. An opportunity to alter the A number exists.

The only welding processes I noted in ASME Section IX that didn't include both the A number or filler metal requirements are those where the base metal is not actually melted during the welding process, such as resistance welding, flash welding, and friction welding.

Hope this helps.

Best regards - Al

 

[GenB]

it will be an essential variable in its type of welding because it does not apply to the WPS(PQR) used in any other
form of welding using filler metal,
A WPS w/o using filler metal can be easily done and w/o restrictions.
genb