I write a preliminary WPS for the welder to follow. It provides the purchasing people with the information they need to purchase the right base metal and correct filler metal. It lets the shop people know what edge preparation is required and how big each piece needs to be and it lets them know that the direction of roll is important and that the orientation of e pieces relative to the direction of roll is critical. It tells the welder what he needs to know when it comes to welding of the test assembly. It lists the filler metal and the diameter of the filler metal I want to be used. It lists the manufacturer and the specific brand name if it is important (it is for certain applications). It provides the welder with a relatively tight range of welding parameters that I want to be used if heat input must be controlled. In short, it is the recipe I want the company to follow when welding the test assembly.
Unlike some facilities, I exercise more control than simply telling welder to "Weld this!" and walking away.
I do list the preliminary WPS on my PQR. It is part of the welding documentation just as is the certified material test report for the base metal, the certification for the filler metal used, and copies of the original laboratory test reports.
I guess it all boils down to level of sophistication of the weld being performed.
Guys,
Not sure I understand.
A PQR can be used to write 1, 10 or 100 WPS's.
Why would you list the WPS number on the PQR ?
Do you revise the PQR every time you write a new WPS based on that PQR ?
You list the PQR number on the WPS so you can reference back to the original PQR - not the other way around.
Just my thoughts,
Cheers,
DD
I follow GTAW's practice. Your weld procedure generally allows more range in variables. The PQR lists the actual variables used in the process. Ultimately, the PQR proves out the WPS. From that PQR you can generate additional WPS's, often to cover requirements of a different construction code, as long as you work within the welding code requirements for variables. You may not always change welding code variables, but instead cover the fine print in another construction code. This prevents you from having to make a new PQR every time there is a procedure change, when the changes are not significant related to the code requirements and qualifications.
jwhit,
I think you have not understood the content of my reply.
You have highlighted actual variables - what is actual about a WPS number ?
If I intend to write numerous WPS's in the future using a particular PQR why would I list anything on the PQR when I don't know for certain how I will use that PQR in the future.
Example: I have PQR-CS-GTAW-001 and I then write a WPS-CS-GTAW-001 and this is then listed on the PQR.
In the future I then write WPS-CS-GTAW-002 based on the original PQR.
I am not supposed to revise the PQR because it is a record of actual variables so what can I do when questions are asked by an auditor as to why the WPS number listed on the PQR is different to the one I am proposing to use ?
Then, further down the track I write WPS-CS-GTAW-003.
Again, revise the PQR or risk questions from an auditor as to why the documents don't match ?
Please explain to me the benefits of listing a WPS number on the PQR - I see only negatives, I cannot see any positives in listing the WPS number.
The preliminary WPS provides specific information to all the interested parties that participate in the qualification of a WPS.
The purpose of a PQR is to record the actual welding variables used to qualify a WPS. If the test results meets the requirements of the applicable welding standard, the preliminary WPS becomes a qualified WPS. For production purposes, the scope, i.e., ranges listed by the preliminary WPS are revised to include production requirements.
As noted, several WPS can be written on the basis of the successful qualification of the initial preliminary WPS. There is no limit on the number of production WPSs that can be generated.
Recording the identification of the preliminary WPS on the PQR is a matter of record keeping. There are instances where the preliminary WPS may have to be revised to account for the unavailability of the appropriate base metal, filler metal, or shielding gas. It simply part of maintaining proper records and controls on welding operations.
Some organization side step the need for a preliminary WPS. They are free to take any approach they deem adequate for their welding operations. Some operations are very informal and relatively straight forward. Others operations are more involved and require a more thorough approach. If a preliminary WPS is utilized, it should be recorded on the PQR just as one records the heat and lot number of the base metal and filler metal and all other supporting documentation.
Some codes and customers do not require the inclusion of all original laboratory test reports and material certifications as part of the PQR documentation. Some customers do require copies of supporting documentation. It is simply a matter of what the particular welding standard and customer requires.
I probably record more information then is required by certain codes, but I can go back a review exactly what was done to qualify the WPS at any future time. When something goes awry, I like to be able to review all the documentation to see what went wrong so the same mistake isn't made a second time. When a PQR doesn't pass all the required tests, it isn't always a case of deficient welder's skill. In my operations, the preliminary WPS is often reviewed before any attempt is made to purchase the materials and striking the welding arc. As an example; one welding procedure I worked on require a specific base metal alloy and cost $42k for material alone. Needless to say, the preliminary WPS passed through several hands and multiple reviews before any material was ordered.
The more complex the work, the more formalized the system needed to ensure time and materials are not wasted. The PQR should serve as an independent verification the welder did what was specified. Did the welder use the right base metal? Was it the right specification? Is there complete documentation to ensure the right base metal was used? Did the welder use parameters that were within the specified ranges due to heat input considerations? Is there a record of welding parameters used for each and every weld bead deposited? If not, what assurance is there that the welder followed the preliminary WPS? Where the test results acceptable and is there an audit trail available? The list of questions continues, but it is completed sufficient to illustrate my point.
GTAW pretty much says it all. What I will add is that if you are required to weld to the European Codes, you are pretty much forced into doing a pWPS. Doesn't matter if you like it or understand the logic, you have to do it. EN15607 for Qualification of Welding Procedures states: The Manufacturer SHALL prepare a pWPS and ensure that it is applicable for the actual production, etc. It then adds "Each pWPS SHALL be used as a basis for establishment of WPQR" and so on. When the pWPS has been successfully qualified, it becomes the WPS.
Al,
The original question was "Is it necessary to mention the WPS No. on the PQR" ? and it was posted in the ASME section.
The correct answer is "No, it is not necessary" - but you can do it if you want to as you detailed in your response.
Regards,
DD
Please let's keep it rolling. Pandittan and DD. From all of us, Analyzing the situation here: listing the WPS used to weld a PQR is not necessary... It is mandatory. regards, genblr.
" listing the WPS used to weld a PQR is not necessary... It is mandatory."
Incorrect. At the time you do a PQR, there is no true WPS...because without qualifying it, it cannot yet be approved and accepted into your program. A "preliminary WPS" equates to nothing more than notes or an outline. It is not an official or approved document, based on ASME Sect IX.
As mentioned above, since you can write an unlimited number of WPS's, supported by one PQR, it makes no sense to put the WPS number on the PQR...because it is a RECORD of what happened on one specific day and one specific weld. 2yrs later, revising the PQR to include a WPS number that didn't exist at the time of the PQR could be construed as fraudulent, IMO...so I wouldn't do it. If you want to do something like a spreadsheet to show which WPS's are qualified by each PQR, for your own information, there's no problem with it..but I wouldn't put it on the PQR.
No, a WPS is not an "approved" document, at least until testing is complete. On the other hand, you should sit down and write a pWPS or WPS first. That document gives the welder the parameters that he is to use for welding the PQR test coupon. The PQR is a record of the ACTUAL parameters used by the welder, while welding IAW the WPS you generated. Someone should be recording the essential variables used during welding of the coupon. The pWPS or WPS is thus verified by the results of the testing done to the PQR coupon. Also, lets not lose sight of the fact that the WPS lists acceptable ranges for the parameters used, the PQR may have ranges, and probably should, but they will be much tighter than the actual procedure. You do not revise a PQR to show later WPS's that use that PQR to qualify them. Multiple PQR's can support a single WPS. The PQR supports the WPS, not the other way around. If you are changing Essential Variables, then you are back to step one, writing a new procedure and proving out a new PQR.
It took me years to wrap my head around this concept, but having finally figured out that you need a set of parameters first has made my job much easier. In a sense it is a case of what came first, the chicken or the egg.
jwhit,
In a perfect world what you and Al have noted is the way it should be done.
However, in the real world it is sometimes totally different.
There are thousands and thousands of engineering / fabrication shops around the world who do not have a Welding Engineer or an employee with the required technical knowledge to write a pWPS.
What they do is pick the best welder in the company, tell him the weld process, tell him the material, tell him the thickness, tell him what joint prep is required and tell him the required consumable.
Amps, volts, travel speed etc are left to the welder to decide what he/she considers optimum.
Those parameters are then recorded and form the basis of the PQR.
I personally think the pWPS is a great idea but unless it is written by someone with sufficient knowledge / experience it is generally of no use to the welder at all.
Cheers,
DD
All too often the conditions you cite are exactly the case.
"I personally think the pWPS is a great idea but unless it is written by someone with sufficient knowledge / experience it is generally of no use to the welder at all."
I agree and I say the same is true of the WPS used for production. Based on past posts, I believe you and I are in agreement that a WPS that is not founded on good data serves little purpose to the people that are most likely in need of good data; the welders.
Since I am basing my response on ASME Section IX, it should be noted that it is not a requirement to record the actual welding parameters used while welding the test assembly. If one does no more than the absolute minimum to comply with Section IX, only essential (and when notch toughness is invoked, the supplemental) variables must be recorded on the PQR. I find it difficult to write a WPS that will replicate the welds of the test assembly (PQR) if I do not record all the test data while the test assembly is welded. That is my way of saying that meeting the minimum requirements of the welding standard may not be sufficient to make an informed decision regarding the production welds.
Few welders are in a position to record the welding parameters by watching meters and stop watches while they are busy welding the test coupon. With that in mind, even though Section IX does not require a test witness be present to record such data, I must ask the question of how else is the test data to be collected? Without the test data, how is one to write a WPS with meaningful welding parameters for welders to use to make production welds? Few welders have any idea of what their actual travel speed is while depositing a weld, yet it is just one of several nonessential variable that should be controlled if consistent results are expected once production starts.
As for the PWPS, it is required when specified by the applicable welding standard and there are several that do list it as necessary. After all, the purpose of welding a test assembly is to qualify the WPS. The WPS used in production is a variant of the now qualified WPS assuming the conditions listed in the PWPS are proven to produce acceptable results.
I guess I look at it this way, the code or standard provides the user with the minimum requirements that must be met. It is up to the contractor to decide how and the means by which those requirements are met. If the operation is not terribly sophisticated and the welding fairly rudimentary, a casual approach will work. The analogy is changing the tire on the family car. The approach taken by the average backyard mechanic is to rummage around to find a suitable jack, grab a wrench or two, begin removing the lug nuts, and continue until the tire is changed. The process is simple and requires little fore thought. However, the process of changing a tire on a multimillion dollar aircraft is much more regimented and formalized. The cost of failure involves more than financial repercussions. A disaster will change the lives of hundreds of people.
When conducting training for engineers and inspectors that will be tasked with qualifying WPSs or possibly designing welds, I always recommend the newly minted engineer or inspector to spend time with the welders to decide on the best course of action. Those decisions are translated into the PWPS to make sure everyone understands what must be done. The more involved and complicated the weld, the more important that everyone know what must be done. It can be very frustrating to have a test weld made only to find out notch toughness is required, but no one recorded the heat input of each weld bead.
The PWPS is just another part of the planning process to decide what has to be done and how it will be done so all the code and contract requirements are met.
ASME specified the requirements that must be met, but not how those requirements are to be met. Is a PWPS needed? Maybe not if it is something that is done on a regular basis just as changing the tire on the family car does not require a set of written instruction.
When witnessing the welding of the test plate (again, there is nothing in Section IX that says I have to witness the actual welding), I verify everything is as specified by the PWPS. It serves as a checklist of what is to be welded and how it is to be welded. Is it the right material? Is it the right filler metal? Is it the correct shielding gas? Nope! Wrong gas. Why? Is there a reason the welder isn't using the gas that was specified?
The importance of following through with verifying all the proper materials, etc. were used many years ago. The contractor decided to switch the shielding gas to Argon. The WPSs had to be qualified for the new shielding gas. All the WPSs had to be submitted to the US Government for approval and their blessing. The WPS was qualified in my absence. Everyone assumed the welder used the correct gas. It was only after the WPS and supporting PQR was blessed by the government that we learned the welder used Helium. Ouch! That was a lesson that will not be repeated soon.
Are you qualifying a WPS for ASTM A53 schedule 40 6 inch pipe with E7010? You probably do not need a formal PWPS to meet ASME Section IX.
Do you need to be a welding engineer to write a PWPS? Heck no, anyone other than the CAWI can write a PWPS.
