Writing and development of WPS's

Date 06-17-2014 12:09 Edited 06-17-2014 12:22

The key is to remember the WPS is intended to provide direction to the welder.

Like a cook book recipe, it should provide sufficient information that the welder can set up the equipment, prepare the joint, and weld the joint to provide the required mechanical properties and soundness. If the information listed is in a format that only someone that has access to the code or other reference document can use the WPS, it has lost its effectiveness.

AWS D1.1 divides the carbon and high strength low alloy steels into groups. However, the group number means little to the welder that doesn't have a copy of the code. Likewise, referencing prequalified joint details per Figure 3.3 and 3.4 means little to the welder or fitter that needs to know the groove angle, root opening, etc. Thus, the WPS that refers to base metal groups and joint details found only in the code are of little use to the welder.

The same holds true for WPSs written to meet ASME construction codes. Section IX is typically modified by the particular construction code, i.e., Section I, Section VIII, B31.3, etc. A WPS listing all P8 base metals means very little to the average welder. It is not information found on pipe or structural shapes. In addition, by only referencing a P number (or group number when working with AWS), the welder can be mislead to believe one base metal can be substituted for another in the same P number group. This is far from the case and it can result in serious problems once the material is placed into service.

As I have mentioned before, engineers that have little background in welding write many WPSs. They tend to write WPSs with other engineers in mind. They meet the letter the code without producing a document that is useful to the individuals that need to apply the information to produce production welds.

While there are CWIs that have the background to write WPSs, most CWI preparation courses do little to prepare the CWI to write a WPS. Likewise, the CWI examination do not assess the CWI’s ability to write a WPS. Many CWIs are ill prepared to write WPSs, but for many companies, there is no one else in the organization with the knowledge needed to develop the documentation needed by the production welders.

Rarely can one WPS meet the needs of the welder for all production needs. Generally, the WPS should be limited to several typical joints. For instance, a single WPS intended for fillet welds and a separate WPS for groove welds using a limited range of electrode diameters can do the job. The individual tasked with writing the WPS has to understand the production needs in order to develop a WPS. It is for that reason I find the SWPS sold by the AWS to be of little value to the contractor or the welder that must use them. They employ the philosophy of “one shoe fits all.” They are too broad and ill defined. They do not provide the welder with the information needed to make welds that meet the code or customer requirements. A contractor that employs a single WPS is no different than a car dealership that sells one car model or a single truck model. Different tasks and individuals have different needs. Manufacturers build several models of automobiles and trucks to suit the needs and preferences of their customers. Unfortunately, it is easy to develop a myopic view and assume everyone does everything the same way.

Of all the welding standards I have used, AWS D1 structural codes do the best job of providing the individual tasked with developing welding documentation a rational basis of doing so. The tables of essential variables included in AWS D1.1, D1.2, etc. provide a reasonable approach to limiting the welding parameters to “usable” ranges. The contractor always has the opportunity to expand the ranges permitted by demonstrating the extended ranges produce acceptable results.

That tact I have adopted is to qualify the fillet welds first. Once acceptable fillet welds are produced, I verify the proposed procedure is capable of producing the mechanical properties by welding a grooved test assembly using the parameters established by qualifying the fillet welds. It is typical to have to weld several samples using different parameters to obtain suitable fillet weld samples. I like to have two welders qualify the fillet weld to establish a reasonable range for the current, voltage, travel speed, etc. I then tabulate the values and use a statistical analysis program available with MS Excel to determine suitable welding parameters for production. The more samples successfully welded, the more valid the range of parameters listed by the WPS. The key is to witness the testing and to record the welding parameters used by the welders. While the codes do not list a requirement for the test to be witnessed and the parameters recorded, it is a key element in developing a WPS that provides the welder with useful information (realistic welding parameters).

I find it interesting that ASME lists welding parameters such as arc voltage, welding current, travel speed, etc. as nonessential variables. Nonessential variables do not need to be recorded on the PQR. Without that information, what is the rational of the parameters listed by the WPS? Are the parameters listed “pencil whipped?” More than likely. Thus, we have another WPS the serves little purpose to the welder and is relegated to the circular file.

The bottom line is that the average welder should be able to use the welding parameters listed by the WPS to produce a sound weld. The joint details should be easily accessed by the welder and the fitter preparing or fitting the joint. While I haven't addressed visual acceptance criteria, it is important that the workers understand what acceptance criteria is applicable. The latter two subjects can be addressed by the WPS or separate working documents. The key to success on the production floor is to keep everyone informed of the project requirements. Unfortunately, few contractors are good at communicating the requirements to the production floor. "They are welders, they should know." Wow, thank the Lord for management. They keep me employed.

Best regards - Al

By js55

Date 06-17-2014 14:40

Al,
The rationale is in the word itself. Non-essential. The idea of essential variable in ASME has nothing to do with what we may think of as 'important'. The idea of essential in ASME is tied into the testing regime. Tensiles and bends. Its a very 'engineering' way of thinking. Much like a functional definition in the world of science.
When an essential variable is determined it is the consensus of the committee that this will effect tensiles and bends to a degree that will cause them to pass or fail minimum engineering standards.
For example, groove design, root spacing, backing, filler metal diameter, welding position, stringer or weave, method of cleaning, polarity, etc. These things may effect strength or ductility but well within the scatter band and not to a detrimental degree procedurally speaking. It may be that a welder may screw it up in position but this is not a procedural issue. Its a performance issue. AWS thinks about this differently.
It may certainly seem like a gap when wishing to dot I's and cross t's. However, it has withstood the test of decades. Of all the failures that have resulted over the last almost hundred years of ASME's existence you would be hard pressed to find a single failure due to somebody leaving a non-essential variable off of a PQR.

By js55

Date 06-17-2014 14:42

Al,
And one more thing. Try as they might (though they really don't) no Code or Standard can prevent pencil whipping. Those of an unscrupulous attitude will find a way no matter what.

By 803056

Date 06-17-2014 16:19

Written by engineers, for engineers.

Kind of misses the mission of a WPS and misses the point of why welders should "follow" a WPS.

Al

By js55

Date 06-17-2014 17:23

Al,
We're kinda mixing PQR's and WPS's here.
Your statement pertaining to non-essential variables in PQR's does not apply to WPS's wherein non-essential variables must be described (QW-200.1(b)).
However, having said this, there is nothing in ASME that forces the idea of a WPS written by engineers for engineers. And there is nothing in ASME that allows it any more than say API or AWS. Conveying information in the WPS depends upon the skill of the person writing the WPS. I might just as easily argue that AWS drives the idea of a WPS written by QA types for QA types. I mean, as earlier posts indicated, if you find your welders are comfortable welding in ranges beyond that allowed by AWS simply write another WPS.
Huh?
The ranges established by AWS are arbitrary.
This is a classic example of documentation for documentation sake, and has absolutely nothing to do with weld quality or viability. If it were the range limitations would be backed by empirical data. They are not.
In fact, john mentioned the KISS method. Only AWS doesn't allow the KISS method. They make you perpetuate meaningless paper. This is not simplicity. It does not facilitate the ease of compliance.

By 803056

Date 06-17-2014 18:46

My point is that in the absence of recording the welding parameters (in the PQR) while welding the test coupon, there little no basis of providing that information in the WPS.

While the ranges permitted by the tables that pertain to WPSs qualified by testing in the AWS structural welding codes may appear empirical, they do serve as a starting point for the parameters to be listed by the WPS. The values listed by the WPS are based on the data collected while welding the test coupon. It is an attempt to prevent the “Goofies” of our industry from listing the welding parameters as: voltage: 0 to 220, amperage: 0 to 400, travel speed: 0 to 40 ipm.

It is unfortunate that the idea of providing the welder with useful information escapes many users of ASME. You are correct in your assessment that many ASME WPSs are meaningless paper. Perhaps that is because all too often the parameters listed by the WPS are not based on data collected while welding the test coupon. ASME doesn't even require the contractor to collect the data they consider to be nonessential. I harken back to an audit I performed at a company that based all their WPSs on ASME Section IX. As I understand it, they constructed nuclear reactors at one time. Back on subject; while reviewing the welding documentation with their "welding engineer," I commented the PQR didn't list who witnessed the welding of the test coupons. He quickly responded there is no code requirement to have a test witness. While I agreed, I mentioned that the PQR listed the welding parameters used when the test assembly was welded. I asked where those “actual” values for arc voltage, welding current, travel speed, interpass temperature, etc. came from. His response was that the welder recorded the values while welding the test coupon. I mused that the welder must be very skilled and expressed an interest in meeting such a skilled lad. No problem, the welding stations were a mere 50 years away.

The engineer was kind enough to introduce me to the welder. I asked the welder if he remembered welding the test coupons as I handed the PQR to him. He commented he remembered it well. They had to weld several coupons before they were successful. I asked if he remembered collecting the values for arc voltage, current, travel speed, etc. I thought his response said it very nicely:

"Buddy, you don't know jack about welding do you."

"Whatever do you mean?" I implored.

"If you ever struck an arc in your life, you would know you can't weld and look at the meters on the machine at the same time!" was his retort.

Case made. The welding documents were just so much bull dung. The engineer said, "Al, I will requalify these WPSs and I will personally witness the welding. I will record the parameters while the welder is welding them."

The ASME codes serve their purposes. I applaud their system of checks and balances. The ASME only authorizes manufacturers and contractors that meet ASME’s requirements. It is a working relationship between the code body, the insurer, and the contractor.

Unfortunately the number one complaint I hear from welders is that the ASME based WPSs they are using on the production floor are not relevant to the work they are doing.

I believe you and I agree that writing a WPS for the sake of meeting a code requirement is counterproductive and in short; a waste of time. There is no single, one size fits all WPS that is suitable for all welding. It takes time to understand the needs of the welder and the contractor.

By js55

Date 06-17-2014 19:56

Al,
The point is, there is no mechanical nor metallurgical justification for requiring the non essential variables to be recorded.
And I said many AWS WPS's are meaningless. I think you meant that, unless you are messin with me. :grin:

And its interesting that you state it as: " collect the data they consider non essential".
Demonstrate how the non-essential variables effect tensiles and bends.
For if you don't tie it to actual test results, your just making something up.
For example:
Prove to me going from 1/8" filler to 3/32" filler will cause an inherent metallurgical or mechanical failure.
Prove to me going from a U-groove to a V-Groove will cause an inherent mechanical or metallurgical failure.
And keep in mind, when you attempt this, you cannot think in terms of welder capability. That's not inherently mechanical or metallurgical. Its performance.
If you cannot do this then you have just demonstrated why these things are non-essential as defined by ASME.
Now, as I continue to make my argument keep in mind that all these things you speak of I do for thoroughness.
I am simply arguing ASME reasoning. Which I believe is valid.
ASME is an empirical beast. If you bring data to prove your point they can be convinced.

Oh, and one more thing, you and I agree on far more than is evident here. But disagreement is more fun. And I learn more.

My friend.

By 803056

Date 06-17-2014 21:53 Edited 06-17-2014 21:57

Differences in philosophy. ASME apparently doesn't consider the "enabling" factors, i.e., factors that enable the welder to make a "good" weld that is sound and produces the mechanical properties necessary to provide a suitable structure.

Per ASME Section IX, the joint details are nonessential variables. Based on that philosophy, the welder that cannot weld a 1-inch thick plate prepared as a single sided groove weld with no root opening is lacking skill. I believe it is folly for ASME to consider the joint detail to be only a matter of the welder's skill. Likewise, I believe it is a short sighted of ASME to fail to consider the electrode diameter when formulating a WPS. Is it one's skill that prevents a welder from depositing a groove weld in the overhead position with a 1/2 inch diameter SMAW electrode? I don't believe that to be the case. Likewise, I don't believe it is the absence of skill that prevents a welder from using a 5/32 inch diameter FCAW electrode in the overhead position.

There are many factors to consider when developing a WPS or qualifying a WPS. Whether the welder can properly access the joint is more than simply a matter of skill. Maybe that is why so many mechanical engineers design so many assemblies that are impossible to weld. Weld cracking; must be a welder skill issue. Incomplete joint penetration: must be a welder skill issue.

While switch from a 3/32 inch diameter electrode to a 1/8 inch diameter electrode, or vice versa, while welding with the SMAW process may not prove to be a fatal flaw, going from a small diameter to a very large diameter may have a significant impact on the welder's ability to make a sound weld and it has nothing to do with the welder's skill. I would hang my hat on the forces of nature, i.e., surface tension and gravity would come into play.

The reason I collect data while welding the test coupon is to have a rational basis of developing the parameters to be used listed by the WPS. I like to list parameters that will provide consistent results regardless of who the welder is. To put it a different way, rather than pull the parameters from the ether, I utilize the parameters used to weld the actual test coupon. Unless the welding process is mechanized or automatic, there will be some variability in the arc voltage, amperage, and travel speed from one weld pass to the next.

I liken the ASME approach to saying if I develop an internal combustion engine that runs on gasoline, it should also run on diesel fuel. Most mechanics would disagree with that position. Likewise, many welders disagree with ASME's position that a number of nonessential variables (per ASME) have little or no impact on enabling them to make a sound weld. Thank the good Lord ASME isn't developing the training given to medical doctors. Somehow, ASME seems to largely overlook the human element.

You are so right about one thing, it is fun to argue the differences between ASME and other rational based welding standards.

Al

By welderbrent (*****)

Date 06-17-2014 22:40

Constructive, informative, lively, passionate, DEBATE. Not, arguing.

And keep it up. I learn more from you two, with help from a couple of others along the way, than going to some of the classes I have been to on 'The How's and Why's of Welding Procedures'. Even the current 'modified, updated, two part' seminar doesn't totally fill the billing that is used as it's promotional advertising.

He Is In Control, Have a Great Day, Brent

By js55

Date 06-18-2014 12:37

brent,
I enjoy debating with Al. His voluminous knowledge forces me to either clarify my foggy thinking or shut up. :grin:

By welderbrent (*****)

Date 06-18-2014 16:07

I know, and I love it and the volumes of information you two pass on during those debates. I just wanted to clarify language because we don't need newbies to get a sense of bickering, backbiting, arguing, and that this forum is a bunch of egocentric, prideful, self elated, never wrong, inspectors who can't come to any agreement about anything. (Oh, that does sound like me doesn't it?? :eek:

) And we know that there are some here who honestly believe that of us, to our shame.

But, the codes are a difficult thing. Especially in application. And while I try to steer clear of areas outside my expertise I sometimes chime in and say something that ends up being off the wall totally. At which time I, and I know several others of you have as well, try to express my humble learning spirit and say so in order to make sure others know I recognize my error and that I just learned something.

Many times, these errors occur because the OP doesn't give us all pertinent information at the beginning and we start in without all the facts then we get hit with more info and say OOOPPPPSSS. Gotta start over because that changes everything. Adding to that is my constant pet peeve about the clearness, or lack there of, and fragile nature of all communications and especially this social networking stuff.

So, we then come to the point that many threads over the years revolve around as to application of methodology of applying certain aspects of our codes. There is no simple answer as we have to look at the applicable code, the AISC Construction Manual with the Code of Standard Practice (not always but often applies to the job), the IBC, and especially the Job Specifications/Contract Documents/General Notes and all other communications with instructions and directions on how to complete the customer's project. When putting all of this together we can still get a picture that leaves room for the inspectors to make some judgement calls (I know I will take heat for that one but couldn't think of any other way to word it).

And let's face it, none of our codes is perfect. If they were they wouldn't need so many addendum's, errata, and editing during following editions. They will always change due to technology, science, research, that dictates changes in practice, but there are always needs for changing language to try to clarify areas of use. Thus, Official Interpretations. Not to mention, RFI's; which should not be viewed or taken as an interpretation of code that the inspector must follow forever, it is only the engineer's job expectation which may be totally outside the intent of the code and should not be taken as new direction for every other job the inspector ever works on.

If I am losing some, I am going on about two threads ongoing at this time. Both are somewhat overlapping so I may be making some points that go for both.

I better stop for now, just woke up and my head is still fuzzy. I don't know how some people can tolerate this night shift stuff. I cannot sleep when the sun is up. Makes that two hour drive home in the middle of the night/morning a very long trip.

He Is In Control, Have a Great Day, Brent

By js55

Date 06-18-2014 16:46

So much of the material presented in here has been gone over again and again. And while I recognize the importance of assisting those with less experience, that is not really what I come in here for. I come in here to challenge myself with guys like Al, and Gerald, and Henry, and Lawrence, and nantong, and many others by pushing the envelope.

By welderbrent (*****)

Date 06-18-2014 17:10

I know it JS. And I appreciate that this is a venue for all levels of those interested in the welding industry from all applications, engineers, educators, welders, inspectors, students, management, and more.

I also recognize that most of us will never be on a level of yourself, Henry, Al, Lawrence, John, Nantong, Glyn, Electrode (forgot his name), Allan, Gerald, and so many more. That is where the rest of us benefit from these discussions. I can't walk away from here without learning something. That is the result of constructive debate. Far different from destructive arguing which genders discord, anger, resentment, bad attitudes, etc.

Don't get me wrong, I don't feel a spirit of arguing between you and Al. Not even between you and ...(other thread person). Sometimes the conflicts are one sided and we scratch our heads asking 'where did that come from?'. And then try to work it out and let them know what we said was not intended to be a personal attack. Though it may in application be very personal, it was a comment directed at one's motives, spirit, attitude, and application of the working code.

Anyway, keep going. Even if largely directed at ASME which is not my forte by any stretch, I see application to D1.1 for WPS's and PQR's as well and always find myself refining my personal application of how to fill out WPS's when I follow you guys in your debates.

Thank goodness almost all of my WPS's are Prequalified in D1.1. So much easier to deal with and yet more important and needful to be properly completed than many give them credit for.

He Is In Control, Have a Great Day, Brent

By js55

Date 06-18-2014 12:35

Al,
I don't understand the basis of the first paragraph when clearly ASME requires non-essentials to be addressed on the WPS. The welder does not require the PQR to do this.
The limitations of which you argue are for the PQR only. Not the WPS.
The PQR is a report on testing. The WPS is an instruction to the welder. And not even AWS insists that everything that might be important in a WPS be reported in a PQR. This is not a debate of either or. Its a matter of degree.
And even if it is argued that it would be a good idea to include everything you anticipate to need in the WPS in the PQR, even AWS allows multiple WPS's to be generated from single PQR's which implicitly argues that the developer of the PQR anticipate every possible application of multiple WPS;'s prior to the development of the PQR. This is clearly not expected in ASME nor AWS. So essentially AWS 'slips' into that ASME 'diesel fuel' thinking by peeking out around the curtain and winking.

What this leads to is that the welders 'ability to make a sound weld', as your example argues has nothing to do with the PQR. It does however have something to do with the WPS where the very things of which you are concerned must be addressed.
Or another way of putting it, the filler metal diameter may effect the soundness of the weld from a fusion, or porosity, or slag perspective. But not the inherent strength and ductility of the metal. And therefore it is an issue for the WPS NOT the PQR.
And your sixth paragraph is NOT the ASME position nor the one I have been arguing. The ASME position is not that non-essential variables have little or no impact in making a sound weld. That is the very reason they are required in the WPS. What ASME is arguing is that non-essential variables do not effect the inherent metallurgical and mechanical properties of tensile and bend specimens demonstrating strength and ductility in the testing regime.
'Sound' welds are demonstrated by NDE.
Metallurgical and mechanical properties are demonstrated by PQR's.

And your final flair is most telling. There is a centuries long history of philosophical debate between the empiricists and the rationalists. Or, in other words those that rely on data and experimentation (ASME) and those that make stuff up (AWS). :grin:

By jarsanb (***)

Date 06-18-2014 14:17

I have to say, I really enjoy the debates that 803056 and js55 are involved with. Either with eachother or others. It's like watching siskel and ebert review "A Clockwork Orange". To bad everyone involved with welding doesn't jump on here and learn a thing or two. Sometimes I'm convinced it's the same guy with a split personality.

By js55

Date 06-18-2014 18:52

Well we had to do something to get Al back in here. :grin:

Place wouldn't be the same without him.

By rjtinsp (*)

Date 06-18-2014 19:53

I agree that a WPS should be helpful for a welder I just wish more welders read them. It seems to me that the only people who read the WPS are inspectors or supervisors two tiers above the welder.

Ramon

By ssbn727 (*****)

Date 06-18-2014 21:13

Hey Ramon,

That is because most welders are not encouraged to read them as they should in order to ensure that everyone is on the same page so to speak... :roll:

I always enjoy when Al and Js55 debate because it help us all to take a closer look at the differences between codes, standards, NDT in general and a plethora of other topics that need to be paid attention to as opposed to just skimming through the various complexities one must navigate, discuss and have a keen awareness of... Al & Js55 enable such an environment in this forum when they discuss topics, and as a result encourage others to participate also... :surprised:

As far as my own personal opinion is concerned, I would like to see that every variable is essential especially when life depends on it but then again, that's just me. :twisted:

Respectfully,
Henry

By Superflux (****)

Date 06-19-2014 07:46

Welders can read??? :evil:

I remember taking a Pipefitter's test in 1981 in Norco, La. at the Jack Stanley refinery under construction.
The fella next to me was illiterate and had to have his Journeyman Pipefitter test read to him so he could answer verbally....

By js55

Date 06-19-2014 12:39

Henry,
Life does indeed depend on it.
And every single day I am acutely aware that the smallest mistake on my part could be a severe tragedy for someone else.
However, having said that, and not really wishing to sidetrack this thread anymore than it already has been, a great unspoken reality in all of this, in all engineering, is that we are gambling with lives. We know that there will be a loss of life. And in the name of economy we accept that. Now, this may shake some people up a bit but its true.
For example, we do not impose 100% inspection to our full capability on every weld. We reduce the required inspection on purpose. This is a gamble. We consistently design components in highly dangerous services without full knowledge of how they will respond.
It is not unlike traffic. We know every year many people will die in traffic accidents. But we still insist that the saving of lives is not an absolute. We compromise.
If the old saying 'if it saves one life it is worth doing' was taken seriously all of our speed limits would be 5 mph.
Just some thoughts.

By ssbn727 (*****)

Date 06-21-2014 07:43

I dig... It's called taking risk assessments and executing them... Been there, done that. :wink:

Respectfully,
Henry

By js55

Date 06-19-2014 12:45

Henry,
Ah, and absolute to inspire conversation.
"I would like to see that every variable is essential especially when life depends on it but then again, that's just me."
Every variable?
Which variables?
Only those that currently exist?
Why would those be considered carved in stone?
How about rod angle for GTAW?
Or, how about one that already exists, nozzle size for FCAW?
Are you really arguing that a new qualification needs to be generated when a welder changes the nozzle on his gun?
Or that you would need to utilize every possible nozzle size in your original qualification?
The cost would be astronomical!!!
And is it necessary to save lives?

By js55

Date 06-19-2014 12:51

Henry,
Oh, and then there's the problem of inconsistency in extremities. Currently we can qualify all P1 materials together. Are you arguing that the difference between FCAW nozzles is more important than say, SA-516 50 plate and SA-516 70 plate? Or 304 stainless steel and 347?
Would you eliminate the P-No system to be consistent with the nozzle requalification?

By welderbrent (*****)

Date 06-19-2014 16:35

WOW JS,

Henry really warmed you up with that one. But some very good points. One must be careful when choosing words like 'never', 'always', 'every', etc. They can really change much more than we intend.

He Is In Control, Have a Great Day, Brent

By js55

Date 06-19-2014 17:37

Not the first time Henry has been inspirational.

By ssbn727 (*****)

Date 06-21-2014 07:52

First of all, I only argue with someone face to face so forget that...

Now discussing stuff is different as long as there's no ASSUMING going on like assuming that I mean this or I mean that because that just becomes to chaotic and confusing for everybody... All of those questions aren't necessary J... Because what I mean is that in a perfect world - blah blah blah... In reality, do we live in one - Absolutely NOT!!!
Get it? So relax there pal and take a chill pill okay?

Respectfully (For the most part),
Henry

By 46.00

Date 06-21-2014 11:16

Really! what about PM? do they not count as arguing? You have sent plenty of them!

By ssbn727 (*****)

Date 06-21-2014 16:53 Edited 06-21-2014 17:04

The maturity level you express lately has been - well let's just say disappointing at the very least and it leads me to think that there maybe some outside influences involved with your attitude towards not only myself, but other posters as well... Having said that, there is still hope for you... As long as you stop whining so much about such petty stuff you tend to bring up just for the sake of starting an argument and stop acting/fantasizing as if you are a moderator here... Like I said before Glyn, Grow up already okay. :roll:

By 46.00

Date 06-22-2014 13:24

I'm british, we are allowed to whine! It's in our nature.

By js55

Date 06-23-2014 12:26

Henry,
I am perfectly relaxed. You made a blanket statement I thought warranted further explanation, and would stimulate a good discussion.