Welder qualification Clarification in ASME IX

[duongwe]

Dear all,
There is a question about to AMSE IX to concern Welder Qualification as below:

I had WPS which was build and complied with ASME IX 2010 for welding duplex steel (S31803 of base metal and ER2209 of consumable). there are two problem i need to clarify:
1) Refer to QW-423.1: "Base metal used for welder qualification may be substituted for the metal specified in the WPS in accordance with the following table" it mean i can qualify welder with Carbon Steel base metal and ER2209 consumable

2) Refer to QW-300.2: "shall be responsible for conducting tests to qualify the performance of welders and welding operators in accordance with qualified Welding Procedure Specifications" it mean that i can not qualify welder with Carbon Steel base metal and ER2209 consumable because of not correct with qualified WPS as required of base metal.

This is conflict with my ideal.

Please send me clarification in these.

Thanks in advance

 

[metengr]

If you have a current WPS that has been qualified for use on duplex stainless using using ER2209, you can now qualify other welders using carbon steel base metal, in lieu of duplex stainless base metal, with ER2209 filler metal. I see no conflict with ASME Section IX.

 

[moltenmetal]

OK, there's the ASME IX portion of welder and welding procedure qualification, and then there's the NACE or good corrosion resistance practice portion thereof.

ASME IX concerns itself only with the mechanical strength and ductility etc. of the resulting joint. You're likely using duplex rather than carbon steel or austenitic stainless steel for a reason other than mere mechanical strength.

Personally I would not permit a weld procedure to be qualified for a duplex material merely on the ASME IX criteria. I would also want a ferrite analysis of the resulting weld and HAZ. Since you can't generate the specimens for that kind of examination using carbon steel as the parent metal, you need to use duplex.

 

[bhollands]

I don't think he is trying to qualify the weld procedure using carbon steel plates. He is merely trying to qualify a welder on an existing weld procedure.

I don't think you are reading QW-423.1 correctly. If you have a welder qualify using a weld procedure for P1 material on P1 material then the welder is qualified for all weld procedure that you have that fall in the limits of the table as well as the F number of the filler and welding method of course. So your P1 GMAW qualifies him for P1 - P11, etc. GMAW procedures with filler metals of the same F number.

QW-350 lists the essential variables for welders. The P number is listed as an essential variable. This should mean that for a welders qualification the P number of the base metal for the qualification coupon be the same as the P number for the weld procedure. If so then you could not substitute carbon steel for duplex for a procedure qualification. I know the cast version (CD3MN) does not have a P number assigned so in order to qualify a welder he would be required to weld the same base metal.

Bob

 

[stanweld]

While it is clear that ASME IX permits substitution of carbon steel test coupons for welder qualification to weld duplex stainless, I would also recommend qualifcation to be done on duplex for the reasons sited by moltenmetal. We have seen numerous corrosion failures in duplex welds due to improper/inconsistent welding techniques employed.

I have gone so far as to require automatic orbital welding systems, where possible,to make the welds in the field to provide consistency.

 

[gtaw]

This subject has come up several times recently. The process of qualifying the WPS is a separate fuction from qualifying welders.

ASME permits the contractor to utilize lower cost base metals for the purpose of qualifying the welder. It has nothing to do with production welding. Welder qualification only requires the welder to deposit sound weld metal.

The WPS used for production must consider a different set of welding variables than those used for qualifying the welder. One activity has little to do with the other.

Best regards - Al

 

[aburafdi]

Dear metengr,
You said that:
"you can now qualify other welders using carbon steel base metal, in lieu of duplex stainless base metal, with ER2209 filler metal".

My question: how about requirement of QW301.2 which says "the performance qualification test shall be welded in accordance with qualified WPS, or SWPS....".

I understand that welder skill is more to the manipulation of weld metal, and using carbon steel base metal is far cheaper. However, the Code is saying that way. Is there a Code interpretation for this?

Please advise.
Thanks in advance.