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Procedure Qualification is different to welder qualification. Two seperate things. This is very important to understand. Cant stress that enough.
Procedure Qualification is testing the mechanical properties of the welded joint. The essential variables in Table 4.11 are variables which changed outside the ranges specified then the procedure needs to be requalified. BUTT WELDS Clause 4.1.2 9(b) If using a prequalified joint (which is only good thing about this standard is the amount of these) and qual the procedure, the this WPS can be used in all positions. Butt welds only no mention of Fillets read down further in the standard 4.1.3 then then tells you the ranges and positios to qual a fillet. It is based on leg length size not material thickness (this is also a common misunderstanding in industry). All of the Pressure equipment codes qual fillets by doing butts. AS1554 is a pain.
Welder quals- are testing the welders ability. So we use table 4.12.2 A to select what test we give our welder to do to qual him for the job we are undertaking. Eg a 6G pipe covers a welder to weld any position as this is considered to be the hardest test to complete.
Hope this helps
The AS1796 1 to 9 certs have mixed opinions of their value to industry. The guys that don’t have them bag them because at the end of the day you don’t need them. But I know when looking through resumes I will call the welders that have them first, mainly because they have passed the theory component. I have seen guys with the certs and were very ordinary welders.
I agree with you BB,
At the end of the day ‘Backing’ is anything that supports the root run. As long as all the essential variables are maintained, I can not see a problem.
I would like to see in 1554 some guidance around qualifying multi processes in the same joint, thickness ranges of weld metal deposited by each process. ASME IX is all over this.
I have seen two supporting PQR’s of 2 different processes combined into the one WPS to form a dual process procedure, eg A pipe PQR that was GTAW (full pen no backing) root, fill and cap and pipe PQR FCAW (with backing) fill and cap combined to form a GTAW root FCAW fill and cap WPS. Thus a saving on not having to produce another PQR and further testing. The material, thickness and pipe OD where the same on both PQR’s.
Hi,
Few points.
There are 4 main types of transfer modes in GMAW process, dip, globular, spray and pulse.
So if your WPS have been qualified with say spray trans, when you buy new machines and they have pulse trans you are required to re-qual your WPS.
If qualifying to a pulse proceedure, this procedure becomes pretty much a machine (or type) specific. As a change in any pulse parameter is a change in essentail variable. In my experience many w/shops have invested in one or two pulse machines but not many use them in pulse mode as any procedure quals on them are not transferable across the rest of there welding machines.
Hope this helps.
I will be more specific, I was looking for info on the visual aspects of Hardeness changes that can be seen in the macro.
(k) Thickness limitations for butt welds shall comply with the following:
(i) For material with a thickness of less than 36 mm, Item (o) of Table 4.11(A)
applies.
(ii) For material with a thickness of not less than 36 mm, no upper limit applies.(I) is not applicable as it not less than 36 mm, so go to (ii). There is some grey area here around interpretation.
Hi Bud,
Porosity is one of the main weld defects. There is nothing real specific in GTAW (TIG) in regards to porostiy control, but I will outline below the general reasons and way to stop porosity in welding.
Make sure all surfaces to be joined are clean, free of oil, pains etc (this includes filler material)
Remove any oxide layers, especially in aluminium.
Your work area is shielded from the wind
Choose the correct shielding gas. TIG generally 100% Argon is most suited to all appicaltions and metals
Gas flow is correct 8-10 L/min (GTAW). Going higher can work against youHope this helps you out. Need me to help you with anything more specific drop me a line.
