This article touches upon the the subject of qualified deposited weld thickness for a welder qualified in accordance with ASME Section IX.
Consider the following problem asked in Interpretation IX-10-23.
A welder was qualified on a groove weld test coupon of 10 mm thickness. The welder deposited 2.5 mm thickness of the groove using E6010 electrode, and deposited the remaining 7.5 mm thickness using E7018 electrode. The inquirer then asks following three questions.
- Is this welder qualified to deposit 15 mm maximum of weld metal using E7018?
- Is this welder qualified to deposit 20 mm maximum of weld metal using E6010?
- Lastly, is this welder qualified to deposit 20 mm of weld metal using E6010 plus 15 mm of weld metal using E7018 for a total of 35 mm deposit weld thickness in the same groove?
Now, E6010 and E7018 electrode have different F numbers. So the coupon prepared by the welder can be treated as two different qualifications. Let us list this information in the form of a miniature welder qualification record for ease of understanding.
|Variable||Qualified with||Qualified for|
|Thickness||2.5 mm||5 mm|
|F number||E6010 (F3)||F3|
|Variable||Qualified with||Qualified for|
|Thickness||7.5 mm||15 mm|
|F number||E7018 (F4)||F1 through F4|
The question asked in ‘a’ answers itself, as can be seen in Qualification 2 above, by virtue of QW 404.30/QW 452.1(b).
Consider question asked in ‘b’. The answer to the question is yes. The first 5 mm deposited (in the total of 20 mm) is supported by Qualification 1. QW 404.15/QW 433 permits that welders qualified with F4 electrode can weld with F3 electrode too. Hence, the next 15 mm in the groove get supported by Qualification 2.
Consider the question in ‘c’. The welder is permitted to deposit 15 mm using E7018 and 20 mm using E6010, can he deposit 35 mm in a single groove? The answer is no.
The question is amusing at first, but if you simply apply the variables individually with both the qualifications, the problem solves itself.
The welder is required to deposit 35 mm in a groove. The first 20 mm of the groove get supported by Qualification 1 and Qualification 2, as described above for question in ‘b’. How will the next 15 mm get supported?
In any case, the welder deposited a total of 10 mm in his qualification coupon. So he can deposit only up to a maximum of 20 mm (2t, as per QW 452.1(b)). The answer has been justifiably given as ‘No’ by ASME to the question in Interpretation.
Let us examine the problem a little further. Can this welder deposit 20 mm with E7018?
The first 15 mm get supported by Qualification 2 straightaway. However, the Qualification 1 cannot be used to support the next 5 mm. Because F number is an essential variable, and a welder qualified with F3 is not qualified for welding with F4.
Consider another version of the problem. Assume that the test coupon (on which the welder did his qualification) was 15 mm thick. The welder deposited 7.5 mm thickness with E6010, and remaining 7.5 mm with E7018 electrode. The total deposited weld thickness is 15 mm, that is – more than the 13 mm required by QW 452.1(b) for qualifying the welder for depositing unlimited thickness.
Is the welder qualified for depositing unlimited thickness in job with F number 3 electrodes?
The answer is no. If the coupon had been welded with either one of the electrodes, the total thickness deposited in an individual qualification would be counted as 15 mm. This would qualify him for unlimited thickness in accordance with QW 452.1(b).
Here however, two F numbers have been used. F number is an essential variable. Hence, the coupon has to be treated as two different qualifications. The thickness of the weld metal qualified has to be determined individually for each qualification.
It thus follows that the welder is qualified to deposit up to 15 mm thickness using E6010 and up to 15 mm using E7018 electrode, either collectively in a single groove one after another, or individually in different grooves. In a single groove, he is also qualified to deposit 30 mm with E6010 electrode, like we just saw above.
So this was about how to reckon the qualified deposited weld thickness when multiple welder qualifications have been done through a single test coupon, in accordance with Section IX. Do leave your observation in the comments section below.