QW-423 – Use Of Alternate Base Metal For Welder Qualification Coupon 3

[ethan18]

Hello. I am new to the forum, and this I think is my first post.

I am a welding engineer, closely working with Section IX for a number of years now. Quite a few interesting issues arise when using the code, and I would love to hear other code user’s views on the same.

I have a PQR qualified with P-No. 3 + P-No. 3 base metal. It is required to write a WPS for a welder qualification, and the available material in shop is of P-No. 1. Ordinarily, a P-No. 3 + P-No. 3 PQR does not support WPS having P-No. 1 metal. However, QW-423 permits replacing any metal with any other metal indicated in the same row of table shown under QW-423, for the purpose of performance qualification alone.

So, does this mean I can write a WPS with P-No. 1, with the help of existing PQR?

1. Will this not be a violation of PQR rules of QW-424? (Considering that QW-301 specifies that a welder qualification coupon shall be made with a qualified WPS only.)
2. Sec IX is serious about respecting the rules of QW-424. See the interpretation in attachment. The ‘no’ reply indicates that Sec IX considers PQR sacrosanct, and just because it is a test coupon – does not mean any substitution of base metals can be done willy nilly.

 

[david339933]

I don't see the problem. An unassigned base metal is not in the same row of the table in QW-423. If you have a WPS for P3 - P3 then use that and substitute the P3 for P1.

 

[ethan18]

Noted. However, this sets a couple of questions rolling in mind:

1. Isn't it odd that adopting provisions of one para ends up making us violate other clauses? For example, substituting P3 with P1 violates QW-424. Using a different base metal also ends up in a different A-number of the weld metal, taking into account the dilution of weld metal due to base metal.

2. QW-300 already rules that use of preheat and PWHT can be omitted during the making of welder qualification coupon, even if the wps calls for it. So, out of a total of 8 essential variables (for smaw), 4 are already gone. So much for using a 'qualified wps'.

I know one can be fully compliant with Sec IX, even with all such substitutions, and one must ultimately apply engineering judgment while being within code rules, but one wonders sometimes.

Thanks for your reply anyway, @david339933.

 

[DekDee]

ethan18,
Never lose sight of the reason why we have welder qualifications - we are ascertaining the welders ability.
That has nothing to do with A numbers, nothing to do with weld dilution, nothing to do with the base metals used.
Does the welder have the ability to eg. put in a GTAW root without backing, fill & cap with SMAW and the completed weld is visually acceptable and then passes either bend testing or radiography ?
If you are performing welder qualification ignore the essential variables of QW 250 and focus solely on the essential variables of QW 350.
Cheers,
Shane

 

[weldstan]

Thank you DekDee. ethan18 is overthinking the reasons for welder qualification not to mention the costs involved. Think of the costs involved in qualifying over a hundred welders on a typical construction project with his approach.

 

[david339933]

AlwaysSometimes Maybe Except

 

[ethan18]

That's right. Thanks all for your responses. Just wanted to hear what the intelligentsia of this forum has to say on the matter.

Although DekDee, i get the spirit of what you say, one cannot ignore QW-350 outright, as QW-300 is clear in saying that a performance qualification coupon must be made using a qualified WPS only. So, unless expressly exempted, all essential variables of QW-250 must be satisfied when making a welder qualification coupon.

 

[ethan18]

May I add another thing here.

@weldstan, when you say that the costs involved in qualifying hundreds of welders in a project, I am guessing you are talking about use of preheat & PWHT in making welder qualification coupons, since these are not required by Section IX. Use of preheat & pwht would be wasteful, according to you.

Now, it is correct that preheat is not an essential variable for welder qualification, i will says this - welding with a preheat of, say 220°C, takes some getting used to, and requires some skill (specially with manual gtaw), in my opinion. Most jobs in my shop involve preheat. I therefore, specify preheat for the performance qualification coupons. In doing this, i am compliant with code, and also sure that the welders have had an exposure to preheat. Correct me if you disagree, please.

 

[weldstan]

I waa looking at the cost of materials. CS vs low and high alloys.

 

[DekDee]

Table QW 356 Essential Variables notes for Base Metals QW 403.18

QW-403.18 A change from one P‐Number to any
other P‐Number or to a base metal not listed in Table
QW/QB-422, except as permitted in QW-423

So if qualified on P1 a welder is qualified to weld P3.
IMHO that covers your expressly exempted comment.

 

[ethan18]

I agree @DekDee. No problem with having a welder who was qualified on P1 to weld on P3. This is permitted by QW-423.

I was only pointing to your use of 'you can ignore the essential variables of QW-250'. One cannot ignore QW-250, right? The first few lines of QW-300 say that only a qualified WPS can be used for making a WPQ coupon. This finds reiteration in many interpretations (IX-89-48, IX-16-17, IX-79-47 are a few examples).

And qualified WPS means one compliant with essential variables of QW-250, IMHO.
Cheers

 

[DekDee]

Ethan,
We can go round and round in circles but I will try one more time.
Ok, we start with an ASME IX qualified WPS.
The ASME IX code committee have clearly approved the deletion of PWHT and Preheat for welder qualification (QW 301.2).
Is that still a qualified WPS - of course it is.
The ASME IX code committee have clearly approved the substitution of Base Metal for welder qualification (QW 403.18)
Is that still a qualified WPS - of course it is.
The ASME IX code committee have clearly approved the use of alternative F numbers for welder qualification (QW 433)
Is that still a qualified WPS - of course it is.

In an earlier post you said 4 of 8 essential variables are gone so how can it still be a "qualified" WPS.
Easy, the ASME IX code committee have sanctioned every one of them.

 

[ethan18]

Dekdee, noted. Agreed with you. No disagreement.
Cheers