This is an age-old quandary.
The use of base metal groupings makes life easier for the individual writing the WPS, but what is the primary purpose of the WPS?
If the purpose of the WPS is simply to fulfill a code requirement and to satisfy the engineer that the WPS can produce the required mechanical properties listing the group numbers alone is sufficient and the WPS can be set into the bookcase where it can collect dust and age gracefully.
On the other hand, if you believe the purpose of the WPS is to provide information useful to the welder, you have to look at the contents from a different prospective. I prefer the latter, i.e., the WPS is intended to be read and followed by the welder. As such, the WPS has to contain information the welder can use and it must be presented in a format conducive to use on the shop floor. The listing of the group numbers (AWS) or P-numbers (ASME) or S-numbers (NAVSEA) are of little use to the welder. Such information is not found on the markings typically seen on raw materials stored in racks or the stock room. How are materials marked? That differs from one company to another, but typically the material specification and grade is marked and possibly the purchase order number or and inventory number. There should be a mechanism where the welder can correlate the information contained by the WPS and the markings seen on the raw material. One means of doing that is to use an annex. The WPS can list the appropriate group, P-number, or S-number. The annex can list the appropriate base metal specifications and grades as well as other useful information such as product form, i.e., plate, shapes, fittings, pipe, etc. I also use the annex to list the appropriate preheat temperatures based on material thickness.
I use a similar annex system for joint details. It is cumbersome to list all the applicable joint details with fit-up tolerances in the WPS without the WPS becoming a 20-page document. An annex can be developed that depicts the approved joint details, fit-up tolerances, etc. This is very useful when working with a NAVSEA or AWS welding standard (codes included). Both NAVSEA and AWS have joint details that are appropriate for different applications. The annex provides each welder, designer, and inspector with the needed information without incurring the cost of providing everyone with a personalized copy of the applicable standard. ASME refers the user to the WPS for information about joint details, fit-up requirements, etc. However, it is rare that a WPS written to meet Section IX contains the information required by the applicable construction code. The welder is left in the lurch and left to fend for themselves. When something goes wrong, it is the "welder's fault."
Using different annexes allows the manufacturer to develop a comprehensive welding document system that is easily accessed by the welder. I use a separate annex for each P-number for instance when documenting a system for ASME. Annex A-1 for carbon steels, Annex A-8 for austenitic stainless steels, etc. I have an annex for the joint details and fit-up requirements, and a separate annex for acceptance criteria. Each welding code or standard has different acceptance criteria, so there are several annexes for acceptance criteria, i.e., an annex for D1.1 and a different annex for ASME B31.1 High Pressure Piping.
The WPS lists the information required by the applicable welding standard and it references the appropriate annexes so the welder can find any additional information needed to implement the requirements of the WPS and welding standard.
Any system that is readily accepted by the welders, quality control, and the engineering is going to have to be carefully thought out. However, it will be well worth the effort if it is done properly.
Best regards - Al
Mich-CWI
When I took over my position the previous CWI had written all the WPS's as "Base Metal" Group I/II to Group I/II"
These were written about 10 years ago or more. Since then as my company has grown and expanded into others areas and I started to get alot of negative feedback from third party inspectors, engineers and anyone who had an opinion that the WPS's as written were incorrect.
At that time I was up for an argument and I would always point out that as written per D1.1 they were acceptable, and generally I would win...but I could se their point, and also as Al pointed out above it kind of defeats the purpose becasue you can't ask a welder or fitter "hey, what group is that base metal in? and expect them to know the answer. Then also to pass an audit they would need access to the base metal group chart (which we made sure they had) so that if questioned they could in theory look it up.
That is ALOT of work and effort to expect a shop or field production welder to attempt.
As I needed to update my WPS, I made a few sets one is still generic group I/II, but more importanly I wrote specific WPS's that lists the most common base metals. So it would say A36,A572-50, A992, A500-C as base material this way it easier for everyone involved but I still had a bigger group i/ii in case I needed it.
Hope this helps
Chris
Interesting perspectives. There is always more than one way of doing a job correctly. In my industry, which is mostly piping and pressure vessels with some structural work, it is common for the fabricator to prepare a weld map showing the WPS to be used for each weld joint type on a specific job, or to have a weld traveller so that hold points can be established for in-process inspections and all required NDE and testing for each weld. Occasionally the WPS to be used for each weld is specified on the shop fabrication drawings in a table or in the weld symbols. Weld joint details, such as bevel angle, root face and root opening dimension are typically shown on the job drawings instead of the WPS. This eliminates the need for the welder to have to determine a P-No. or the correct weld joint detail. The welder performs work to the drawings, and weld maps or weld travellers. I have worked both structural and ASME jobs, and each method of control is suited for it's intended application. Similar to Al, we list the base metal specifications for each AWS Group in a general welding specification, which also includes specific weld joint details. The WPS's and general welding specifications are provided to the welders for reference at any time they desire during the work, either in a work package, supervisors office, or tool room where they draw rods.
I use the "General Welding Procedure Manual" approach for some clients that weld to a single welding standard where the changes are infrequent. For job shops where nearly every incoming project utilizes a different welding standard, the annex system saves time and reduces the amount of paperwork the welders have to contend with.
I'm not sure I agree with JS55's assessment that welders are stupid dolts that need to have their hands held as they weld. However, it has been my experience that few welders are sufficiently conversant with the different welding standards to forgo providing them with specific information regarding joint details, acceptance criteria, etc. To do so would be no different from working with an engineer or contractors that purports to weld in accordance with a specific welding standard, but don't have a copy to reference. I suppose they could always write an inquiry to the Forum for answers to question regarding base metals, filler metals, joint details, acceptance criteria, etc.
Just as engineers use reference books to design structures, welders need information that pertains to their job functions. Different companies approach fabrication and manufacturing differently. A manufacturer/production facility usually has the parts and pieces premachined with weld preparations incorporated with the part details. The welder may use fixtures to hold the parts in proper alignment and has no responsibilities other than to deposit a sound weld. A job shop can be a very different environment. It is often the case that the welder is responsible for drawing raw material, cutting material to size, prepping the joints, fitting the parts, as well as welding the component pieces together. In the case of welding to the NAVSEA welding standards, the welder can be responsible for in-process inspections. As such, the information required can be more involved than perhaps a production shop where the welder is responsible for welding one or two typical pieces day in and day out. I have worked with clients in aerospace where the welders have been literally welding the same part for over twenty years. Again, different shops have different needs and the documentation and information needed by the welder can be very different. The welding engineer/consultant needs to understand the level of complexity involved and has to devise a system that works for the client. When it comes to welding, one shoe size does not fit everyone.
Best regards - Al
I know when I write procedures I find it helpful to write 40 or 50 carbon steel procedures to cover all of the carbon steels I deal with. I also have dissimilars to make sure that when I am welding wrought fittings/forgings/castings to pipe (for example an SA-234 WPB tube turn to an SA-106 B pipe) I have sufficient detail to accomodate the chemical/metallurgical/mechanical requirements of both specifications.
I also have seperate procedures for varying filler metals since, if base metal specs are of such importance shouldn't filler specs be too. So I have 40 or 50 carbon steel procedures for GTAW, for SMAW (don't even ask what happens when I switch from 7018 to 7016 that iron oxide can profoundly change things), for GMAW (don't even ask what happens when I switch from 70S-2 to 70S-6), for SAW (EM12K, EM13K), and for FCAW.
My problem has always been I cannot find enough QC fellers to surveil the shop and make sure that my welders are complying with all these variances I have imposed. Since my basic assumption is that welders are not intelligent enough to figure it out I am stuck with an age old quandary. I just can't trust em so I have them surveilling each other to make sure its covered and I have no conflict of interest.
Add to this my problem that I have had customers question if my calibrations are accurate enough to justify such precise variances in electrical parameters.
Its not easy being a welding engineer. Maybe I'll just go back to driving a truck or something. This all just feels too out of control.
js55
That is why I found that simplier is better other wise they end up not using anything.
Just my opinion
But yes it CAN get overwhelming and very timeconsuming to create and maintian all this documentation.
I empathize with your situation and I can understand why you would want to consider driving a truck. However, be forewarned that even driving a truck involves understanding the rules of the road and even require the welder to carry logbooks, etc. Paperwork, paperwork, paperwork, we simply cannot escape it.
We can no longer regard the welder or the truck driver as mushrooms. The days of Fredric Taylor and the dinosaurs are long gone.
The world of trucking and welding have changed with the times. Have you? ;)
Best regards - Al
PS:
I forgot to mention that you must mutliply my A-992 procedures by 3 because the AWS D1.1 + or - 10% is not near enough to match my welders abilities with 1 WPS, and you have to multiply again for flat, horizontal, overhead, uphill, downhill, etc. since the parameters will be different in each, and again for single V, double V, VW, and Humvee.
Oh God, don't even mention my D1.3's with paint coatings.
You have to multiply again because some welders wear Carharts and some wear Dicky's, and twice again because some welders chew Copenhagen and some Skoal, some prefer blondes some brunettes.
I really have no idea how many procedures I have but it takes 10 men and a butch lesbian in lumberjack plaid to pull the file for auditing review. Then again, neither do the auditors so I always pass. :)
If you can't dazzle em with brilliance baffle em with,,,,,,, well, you know.
js55
I'm glad you mentioned the tolerance of D1.1 +/- 10%.
That has been a problem with some of my guys as well, the manufacturer allows a wider range than the code will allow, these guys have been welding soo long they don't want to change, and I have to consider where they set the machine vs. others and sometimes the ranges are too far apart. So yes I do have multiple WPS's for that reason but it sucks.
Perhaps you should read this:
AWS D1.1 Interpretation
Subject: Variable parameters on welding procedures
Code Edition: D1.1:2000
Code Provision: Table 4.5
AWS Log: INQ-21
Inquiry: (1) For a prequalified WPS, is it the intent of AWS D1.1:2000 that a single value or mean value
be specified and the limitations of Table 4.5 be applied to the specified value?
(2) For a prequalified WPS, is it the intent of the AWS D1.1:2000 that a range of values may be
specified and the limitations of Table 4.5 be applied to the specified range?
Response: (1) No. Use of a single value or mean value is neither required nor prohibited.
(2) Yes, as long as the range of values is within the range of the manufacturer's
recommendations, see 5.3.1.2.
OK Marty. I am thoroughly confused.
Since this interpretation is so foreign to my understanding I'd like to pursue exactly how it is this is to be implemented.
What is meant by may be specified and the limitations applied?
This doesn't seem clear to me.
Exactly what would be the specified range and what would be the applied range?
I don't mean in amps or volts, I mean in definition.
If I write a GMAW WPS wherein the amp range is 250 to 350. Is this the specified?
Then what is meant by the applied? A violation of the that which is written in the WPS as long as it doesn't violate more than 10%?
Or is the specified and the applied built into the 250/350 range? In which case what is meant by specified?
We submitted the inquiry because someone insisted we had to write separate WPS's to cover the full range of mfr's suggested amperage range. For example, it was suggested we "specify" a single value, say 120 amps, and "apply" the +/-10% tolerance such that the prequalified WPS could only be used for a range of 108 to 132 amps. It was suggested we had to write a new prequalified WPS if we wanted to weld outside the range, even if it fell within the mfr's suggested range. My response was "hogwash" and submitted the inquiry to get clarification that this is not the intent of the code. The response indicates we can specify any range on the WPS so long as it is within the mfr's suggested range, and we do not have to apply the +/- tolerance as long as the range on the WPS is within the mfr's suggested range.
Just to reiterate an important point of your inquiry, you are dealing with a prequalified WPS, not one qualified by testing.
Best regards - Al
Preferably only two sets of logs. ;)
Just one phrase to keep in mind in all this: Consistent with application and customer's requirements.
With that, I'm off to the TIG table to play with some aluminum. Again.
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