ASME IX Procedure versus Performance thickness ranges 3

[DeanIEng]

Hello Everyone, this is my first post using Eng Tips, having been a regular visitor to find solutions to problems for quite some time.

I have a question that no doubt you ASME experts have answered on many occasions, but I can't seem to find a definitive answer anywhere, so I have joined the forum.

My question is concerned with Procedure thickness range qualified and Performance weld metal thickness range qualified.
Say for example I have a GTAW Groove (Vee Butt) Procedure Qualification Record for a 60.3mm (2 1/2") diameter pipe with parent metal (wall) thickness of 3.91mm. According to table QW 451.1 this qualifies the procedure thickness range 1.6 - 7.92mm. Please correct me if I am wrong.

If impacts are required, they are a supplementary variable in table QW 256, and thus paragraph QW 403.6 is applied and so the base metal thickness range would then be 3.91 to 7.92mm using table 451.1 to obtain the upper limit. This range applies solely to the Procedure.

In the case of Performance qualification, the thickness of weld metal qualified in table 452.1(b) is also 3.91 - 7.82mm. Correct?
So if the procedure does not require impact values, this seems to suggest that the Procedure base metal range is 1.6 - 7.92mm, but the welder is only qualified from 3.91 - 7.92mm weld metal thickness.

This just doesn't seem to sound right, can one of you helpful guys out there clarify this for me?

Many Thanks,........DeanIEng

 

[david339933]

Procedure Qualification 1.6 - 7.82mm with no impacts.

Procedure Qualification with impacts is 1.9mm to 7.82mm - QW-403.6 states that minimum qualified is 1/2T for T<1/4" (6mm)

Performance qualification does not concern itself with a minimum, only maximum. Minimum will be limited by the WPS used...in this case 1/16" w/o impacts or 1.9mm with impacts.

 

[metengr]

The welder is qualified to a maximum of 2t based on table QW-452.1 - 1.6mm to 7.92mm. Impact only pertains to WPS qualification.

 

[DeanIEng]

Ok, thank you for that. So if a base metal of say 10mm (3/8") was used, the procedure range would be 4.8mm (3/16") to 20mm without impacts, and 10 - 20mm with impacts?
Now here is where is where I get confused; The weld metal thickness qualified in the procedure according to 451.1 is 2t, But what is the minimum? is it the thickness of the weld metal deposited in the procedure, or is there no minimum value?

The welder performance range according to 452.1(b) Is for "All" thicknesses of the weld metal in the test coupon up to a maximum of 2t. So the performance range would be 10 - 20 mm in this instance? It just doesn't make sense that the welder would not have the same thickness range qualified as the procedure.

Then there is the performance range of the multi run welds over 13mm (1/2") in table 452.1(b); The statement 'Maximum to be Welded" seems ambiguous. Does it mean that the maximum is the same as the weld metal in the test coupon, or is it to be taken literally that the 'Maximum to be Welded" can be any thickness required in the production environment (no upper limit)?

Sorry to ask so many questions, but here is the final one; If a PQR has impact testing conducted, can it be used to draft a WPS that does not require impacts as well as one that does?

Thank you in anticipation of your help,...............DeanIEng.

 

[SectionIX]

Hi DeanIEng,

With respect to your questions:

1. For your comment regarding weld metal qualified, you are correct: There is no minimum value, only a maximum (2t). However, this could be further restricted by Notes 1 and 2 from ASME Section IX, Table QW 451.1.

2. Regarding welder qualification thickness vs. procedure qualified thickness, there are two standards. Simple as that.

3. "Maximum to be Welded" means unlimited. This applies only if a welder qualifies on a coupon 1/2" and over with a minimum of three layers.

4. If you perform impact testing, you can (and should) write a WPS that counts for impact/non-impact applications. For example, your WPS could read "Base metal qualified: xx mm to xx mm without impacts, and xx-xx mm with impacts". The application will determine whether or not impact requirements apply.

 

[DeanIEng]

david339933, metengr & Section IX,......Your answers have clarified the situation perfectly. Thank you all so much for your help with this. It is very much appreciated.