ASME IX QW-423 & QW-424 3

[Hansac]

Hi there everyone

I was taught and have been teaching others this understanding:

From QW-423 it is implied that a welder qualified to weld Carbon Steel is also qualified to weld Stainless Steel, as the P-Number is grouped in the first row in the table in QW-423.1

However, I was told by someone with "20+ years experience" in oil & gas projects that this is simply "the wrong thing that ASME keep on printing" and that in practice, welders are segregated strictly according to individual P-Numbers and that "stainless steel welding is harder than carbon steel welding"

What is your opinion in this?

I hate to be teaching the wrong thing to my students (I teach ASME IX as a separate course and as a supplementary module to API 510/570 exam preparation class).

By the way, I have *only* a total of 19+ years of experience in Inspection Engineering and started teaching ASME/API courses since 2010, but that's just shameless bragging

Thank you in advance for your replies!!!

 

[weldstan]

F no. is also an essential variable. One can qualify welders on carbon steel coupons with the proper F No. to permit welding of stainless, nickel base alloys and specific copper base alloys defined; however, this is not always a good idea.

 

[gtaw]

ASME Section I X is pretty clear on the base metal P-numbers that the welder is qualified to weld based on the materials used for the test coupon. One must also consider the F-number of the filler metal used. If the F-number changes, the welder must be requalified.

The code delineates the minimum requirements. The contractor has an obligation to meet the minimum requirements, and where it is prudent, go beyond code minimums.

Many welders will totally disagree with the position that carbon steel welds like austenitic stainless steel. The welders are likely to be more familiar with the fluidity of the weld pool and how it responds to the welding arc than an engineer that has very limited (if any) time under the welding helmet. Their opinion is based on the welder's experience, the welding process, the production positions, and the product form they are used to welding. That being the case, there is nothing in the code that prohibits the contractor from giving the welder additional performance tests to verify the welder can produce an acceptable weld.

Along the same lines, i.e., the code delineates the minimum requirements, consider the visual acceptance criteria of Section IX. It has no criteria for undercut, root surface contour, face reinforcement, porosity, etc. However, the actual construction code does have visual acceptance criteria that is considerably more details than Section IX. I have long advocated that the welder's coupon should be evaluated using the visual criteria of the applicable construction code. I see little value in qualifying a welder to Section IX only to discover he or she cannot meet production requirements. My welder performance test coupons are evaluated using the visual criteria of the applicable construction code. This is not required by Section IX, but I feel it is prudent to verify the welders can meet production requirements, not just Section IX.

Best regards - Al

 

[DekDee]

hansac,
Valuable information given to you by weldstan and gtaw.
May I ask how you can be teaching ASME IX to students when you have to ask questions on a very basic subject on an internet forum ???
I have been "living and breathing" ASME IX every day since 1994 but that is just shameless bragging ! LOL !!!
Regards,
DD

 

[Hansac]

DekDee,

indeed your question is valid. As for me asking a "basic" question, I am just perplexed as to why the industry doesn't wish to follow this leeway provided by the Code (F number notwithstanding).

The Code treats carbon and stainless steel welders as the same (again, F-no. notwithstanding). In some parts of the world, the rate for SS welders are higher than CS welders. I understand about the fluidity of weld pool.

I understand a lot of things but I just don't understand why the industry would completely go against ASME IX on this.

Yeah yeah I understand about Code giving minimum requirement, too.

gtaw was giving his experience in making the acceptance criteria used for fabrication to be used in qualifying welders. Again, I understand it is within each organization rights to implement anything above and beyond but why so? Why make things extra difficult when it is not necessary?

I have yet to come across a welder that was qualified to the acceptance criteria of ASME IX and the go on to produce poor weld which failed the acceptance criteria of fabrication codes.

Thanks all the same guys!

 

[gtaw]

Follow me around on a few projects and you see thing that you wouldn't believe are possible.

Qualifying a welder to ASME Section IX isn't that difficult. There are no limits on root reinforcement. Technically, the welder can fill the ID of the pipe solid so that a fly could not fly from one end and out the other and still meet the visual criteria of Section IX. Likewise, the is no visual criteria for face reinforcement. How much reinforcement is too much? Evidently, there are no limits, so if the welder has some undercut, deposit another layer or two or three. Eventually, with luck, the welder will have a weld face without undercut. Oops, my bad, there are no limitations on undercut. So, the welder can have undercut and still pass the visual criteria. "How deep can the undercut be?" one might ask, That's a very good question. If the sample passes the face bend without producing a crack he's good to go or better yet, select a location that is free of undercut. How about porosity? No limits per Section IX. As long as the guided bend test is taken from a location that happens to be free of porosity, all is well.

I could go on, but what is the point? Any contractor that is only interested in providing welders with paperwork is free to do so. The welder might not be able to perform on the job site, but that matters little to anyone that sits in the office or a school that is only interested in churning out welders with "papers." They don't have to contend with real world events. In either case, the realities of the world and economics will catch up with them. Schools that have their student's long term interest in mind and are concerned with building long term relationships with contractors in their area are going to provide the students with "real life" experience and they are going to provide contractors with prospective employees that can meet production requirements.

Best regards - Al

 

[weldstan]

Hansac,
"I have yet to come across a welder..."
You must not have been around too long. In my 40+ years experience, many welders, who were qualified per ASME IX, were terminated for making numerous unacceptable production welds. We terminate far more today than 20 years ago. Defect rates gretaer tha 25% are not uncommon, especially at the start of a construction project.

 

[gtaw]

Weldstan, as someone that has a good amount of experience with welders, which approach makes more sense for the Owner and the contractor doing the work, failing the marginal welder in the test booth or on the job after he has completed several pipe joints?



Best regards - Al

 

[weldstan]

It's always better to cull those marginal welders before they make rejectable welds and the cost of a large number of repairs is always more than the added costs need to assure competent welders. Having said that, one cannot always convince management of same; e.g., we provided restrictive tests for boiler tube welders and most could not pass the restrictive test (just what it was meant to achieve) resulting in management and HR to abandon its use. Reject rate was > 30% (5% random RT required by Client) and astronomical repair costs. Reject rate for welders who passed the restrictive test was < 1.5%. Go figure!!!

 

[gtaw]

No one said you have to be a genius to sit in the boardroom.

Best regards - Al

 

[DekDee]

hansac,
gtaw and I work in similar roles and whilst we don't always agree on everything we both treat welder qualifications the same.
Al (gtaw) imposes the acceptance criteria based on the construction codes the welders will be working to, I go a bit further and accept zero visual weld defects (which as you commented is well over minimum ASME IX requirements).
In 20 years I have never had a client tell me my acceptance criteria is too strict.
I witness welder qualification tests as contractors representative, clients representative and also as third party representative and it is imperative that welders I deem competent can actually reproduce acceptable welds in production.
If I sign my name to a welders qualification certificate and they then go on the job and produce non-acceptable welds then questions will be asked about where they got their qualifications.
Reputation is everything in this business and if I sign my name to a welders qualification certificate then I am confident he/she can reproduce sound welds in production.

Finally, your friend who has had 20+ years in O&G doesn't know what he is talking about,

Regards,
DD

 

[weldstan]

My instructions to our Welder Qualification Instructors is, "inform the prospective welders that at if at any time it is determined that a welder will not be able to make acceptable production welds, the qualification test can and will be terminated. I have terminated welders' qualification when the prospective welder could not hook up his equipment correctly, after depositing 1/4 of the root bead, after excessive intermediate bead grinding, etc.

 

[pandithan]

As GTAW said, fluidity of SS weld is harder than CS due to presence of Ni in SS, As aware, Welding Nickel metals and its alloys is more difficult than other metal. so some technique and skill is required for SS compared to CS