The list of all the material specifications contained within a specific P number is indeed long. However this thread is limited to WPSs intended to be used for welder qualification. As such, it should give specific direction to the welder that is relevant to the test the welder is asked to take.
There have been several threads initiated by welders that felt they were not provided with sufficient information when they were required to take a performance test. In some cases they were given information "after the fact." Some examples sounded like "bait and switch" scams. In some cases a WPS was not even provided. I can only say the examples provided are poor practice and any CWI involved should be admonished. They should know better.
My practice is to have a specific WPS for welder performance testing. It addresses the test they are taking and is very specific with regards to material specification, groove details (if it is a grooved test) or other information relevant to the joint being welded. The WPS has a sketch showing the joint and relevant information such as the length of the pipe nipples in the case of a pipe test, plate dimensions, etc. for structural tests.
The simplicity of the P-number system is for the benefit of the engineer. It does nothing for the welder. Let us not forget that the engineer can easily pull the reference (Section IX) from the bookshelf or access the information for P-numbers from his computer. Few welders carry Section IX in their tool kit and few have access to a computer on the job site. To expect the welder to know that a particular material specification belongs in a specific P-number grouping is like saying there is no reason to have audible signals at pedestrian crossing for blind people. They should know if there is a car is approaching or passing by from the Doppler affect of the car's exhaust.
As for a WPS for production, many shops are welding a limited number of materials within any particular P-number group. The number of specifications involved is relatively few and can be included in an annex if the list gets too long.
I do not agree with the philosophy of "Let's not tell them too much, it's easier to beat them if they make a mistake." or "Leave them in dark, feed them BS and see if they thrive."
If the employer does not provide the welder with useful relevant information, the blame lies with the employer.
You and I have agreed that the information required by Section IX is the minimum information that has to be included in the WPS and PQR. It does not mean the employer cannot add information to the WPS the welder will need for production work.
I will go further to say that a WPS that only includes the required information per Section IX is a waste of valuable paper. It serves no useful purpose in the welder’s hands.
Case in point: P-numbers, there is no direct correlation to the information provided by the supplier in the form of material specifications, etc. listed on the raw material.
Electrode: Specification is required, but not the classification. Do I use a ER308, ER316, ER309, or 310 when welding type 316 all? Does it matter?
Voltage, Wire Feed Speed, and Amperage: not required. Most welder would find such information useful gaging by the number of times welders on the job ask me for that information
The list could go on, but we’ve done that before.
Best regards - Al
I would agree, and in fact write my WPS's with more info. But I also believe most welders are quite intelligent and can grasp a handful of P-No's even more easily than what will always be larger number of specifications. If all the welder has to know is that he is welding on P-1 carbon steel isn't this easier than having to verify that the WPS actually has SA-105, 106, 516, 367, 333, etc.?
If the welding engineer happens to overlook an unusual material spec and didn't rev his WPS then you will still be in compliance with P-No's. Though maybe this argument is thin since welding engineers never make mistakes. :)
One other problem with specification listing on the WPS. Many specs have multiple alloys so what this will lead to is that your, for example carbon steel WPS, your 1 1/4 Cr WPS, your 2 1/4Cr WPS, 5Cr, 9Cr and P91 and your stainless steel WPS's, will all say, SA-182 on them(SA-182 is the most common spec for O-lets and everybody in piping does o-lets).
CS, P11, P22 WPS's will have in common maybe SA-182, SA-234, SA-335.
SA-333 can be on carbon steeel and Ni steel WPS's.
So now its not just the spec but the classification as well the welder needs to be cognizant of.
Not only does this not give the welder any valuable info it increases the confusion. Now I stated earlier I thought welders intelligent
(I wuz wun) but this is just ornery. :)
Does the welder really care if he is welding an SA-234 tube turn to an SA-106 pipe?
What is simpler an SA-105 flange to an SA-106 pipe (with an SA-182 o-let) to an SA-234 tube turn,,,or
Its P1 carbon steel, get to weldin. :)
If the welder could identify that the SA-234 was a P-1, I would agree. My position is that the average welder doesn’t know what materials fall into the different P-number groups.
You make a good point that the material specification may include several alloys. That is all the more reason to provide specific information for the alloy and material specification to be joined as well as the specific filler metal specification and classification for the combination.
P8 welded with an F6, sorry, not enough information.
This isn't a case of the welders not being intelligent. This is a case of not providing useful information to the welder in a form he can use. Welders are not usually familiar with using a welding code, nor do they have access to the code on the job site. Give the welder the tools needed to do the job right. That’s where and when the welding engineer or consultant earns his keep.
Best regards - Al
Al,
I'm confused. I'm not sure what we are debating anymore (even ASME Section IX requires far more than P-No/FNo). If it is your contention that ASME Section IX needs to increase what it requires on the WPS I can understand, and many would agree. If it is your contention that ASME Section IX needs to require everything that is needed by the welder then I would have to say I do not believe this is possible or even desirable to attempt.
I also think that virtually everyone agrees that more information is required. The system I have in place provides more information.
And this is the operative. Developing a system around the code requirements that works.
Somehow I suspect that welders who are truly interested in referencing a WPS, and in the real world they are few, would also somehow not have any trouble understanding that P1 is carbon steel.
WPS says its P1, therefore carbon steel, and you weld it with ER70S-2. You have your base metal and weld metal both required by Section IX. You also have to address amps and volts though the ranges are not dictated.
I also have always believed that WPS's are bit overrated. We have to have them to be sure but they are a template, not an absolute. First, WPS's don't determine what a welder does. A welder has initially determined what the WPS says through the PQR process. And if you have any smarts about you in writing the WPS (rhetorically speaking) you will write your WPS consistent with what the welder has done in the qualification and has proven successful in testing. So there is almost a cart before the horse mentality with a WPS. The welder came first then the PQR/WPS. Yeah I know about the pre qual WPS. Thats even worse. It is still up to the welder. If you don't think this is true (rhetorically speaking) try qualifying a procedure with a rookie. Second, you can have the most comprehensive WPS on the planet and it will still not make a good welder or allow a guy to weld if he doesn't already know how. I have often said myself that a WPS is an instruction, but I will admit this is overstated. In reality it is more of a guideline. Though certain things are absolutes like filler classifications, etc. Amps and Volts and travel speed can vary a great deal.
I know the conversation has drifted a bit but I think it is still a good one.
Another way of putting it is that WPS can assist inexperienced welders, but it is most commonly meaningless to experienced welders.
This statement may come as a shock to many, but there are literally millions of absolutely superb welds being made by guys who have never even seen a WPS. The control system around the WPS is the operative.
OK. I've rambled enough for now. :)
We're both in agreement on the basic concept of the WPS and what information should be included. I believe we're both on the same page in agreeing that there are WPSs that are for "General" use and there are those WPSs that are intended for specific single purpose applications.
Much of the problem, as I see it, is all too often the engineer fails to understand what information the welder needs. The welder's needs are far different than the engineer. To top it off, few engineers have any first hand knowledge of welding. I would say it is akin to the welder writing an outline to perform failure analysis for the engineer to follow. The welder can read a book and get a general idea of what failure analysis is, but until he has actually work a few problems he is at a disadvantage.
ASME looks at the world from an engineer's prospective. ASME's code bodies are comprised for the most part by engineers that are number crunchers. Desk jockeys that rarely if ever visit the shop floor or interface with the weldrrs. Not that I blame the engineer, welders can be an ornery bunch if they don't believe you know your butt from, well you get my drift.
It is no different than CWIs that passed the CWI without having experience as a welder. The CWI that comes from the ranks of the welders typically fare better on the production floor. They have a working knowledge of the processes and they know what to look for, what is important and what is fluff. CWIs that have a strong background in NDT and laboratory work usually do better in the aras of report writing and documentation.
Ideally, engineers would have a better understanding of what the welder has to contend with if they work on the production floor side by side. Welders would have a better appreciation for what the engineer is trying to accomplish if they had some background in strength of materials, statics, etc. Life being what it is, the ideal situation rarely exists.
The secret is to write a WPS that is meaningful to the welder and meets the code requirements and defines the process in sufficient detail that both the experienced welder and the inexperienced welder can get the job done correctly. The fact that the goal is sometimes missed ensures you and I will have plenty of work.
Best regards - Al
I agree Shane!
"Multipass welding required, with no single pass greater than 1/2"-end quote...I'm not familiar with Section IX, do they allow a single pass of 1/2" in any position?....wow.
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