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Here is the rundown. The company I work for wants to qualify a new weld procedure because of a change in the filler metal trade name. So they handed me an old PQR and told me to follow it precisely. Here's the specs of the said PQR:GMAW-P .052" wire180 amps24 voltsHere's the kicker. The test position is 60-90 degrees (3G), the travel speed is 4 ipm, and maximum bead width is 5/8". WTF. IMO, this is like trying to fit a basketball into a pop can, not only is it not possible, it's not even close. Am I wrong? Please tell me if and how this is doable. I'm either going to look like a dumb*** at work or they're asking the impossible. Don't hesitate to let mw know if I have left out necessary info.
Reply:That seems very doable, except for the travel speed. I would measure the WFS for the given settings, then calculate how much filler metal is deposited per minute. Then check that number against the maximum area of the weld for a 4" length and see if it is even physically possible.If it is, then it looks like you should start practicing. If not, then its time to bring that to the attention to the engineer who wrote the WPS.Since you listed a specific travel speed, I take it that this is a mechanized or automated weld? What is the joint prep and material thickness?Have we all gone mad?
Reply:If they handed you an old PQR with that data than it is most certainly possible to make that weld because it has already been qualified. With that said, I feel your pain when it comes to making WPS that covers a wide range of variables in one PQR. Such as heat input, volts, amps, wire speed, inert gas, pulse, pulse on pulse, spray... so on and so forth. The welding engineers I work with will ask me to do a PQR for 316L stainless (for example) and will require these perameters; GTAW ER316/316L filler 3/32 dia. 160-180 amps 3" to 5" inches per min 12 to 16 volts max interpass temp 350 deg. FDo multiple passes (which are all recorded) until min. 3/4" weld deposit Followed with SMAW E316/316L 3/16" dia. 160-200 amps 3" to 4" per min. volts (not specified) max interpass 350 deg. FDo multiple passes until balance is filled.* This is a generic example but perameters are very close to actuals* To follow these perameters makes it a pain in the a$$!!! But it is what they want so I don't argue. They are just trying to get the widest range of variables in one PQR as they can to save them from doing multiple PQR's for one WPS.
Reply:I am not an expert with qualification of welding procedure specifications (WPS) to a code or standard, but I do know that the code, such as ASME, will clearly specify the "essential variables" for the process which may not be changed without a new procedure qualification and procedure qualification record (PQR). What code are you working to, and what are the essential variables for that process?To weld under the existing PQR and WPS you must not change the essential variables, but you may change any other variables.My guess is that the amperage, wire feed speed, and travel speed are not essential variables and therefore you may adjust these as needed to produce a sound weld, and you will be welding within the previously qualified procedure.
Reply:You are being asked because they probably feel that you are the most qualified to see if this will work. Feel honored.Give it an honest effort and report back to them what the results were. Thats all.Tell them what problems you may have had.BTW if you really feel that it is impossible just report back to them that you feel it is not possible and tell them why.Thats all you have to do. Do not let your ego get in the way.Remember they came to YOU and asked YOU. There is a reason.Last edited by Donald Branscom; 03-16-2011 at 09:25 PM.AWS certified welding inspectorAWS certified welder
Reply:When you become an experienced welder you may be asked "silly" questions but do not make fun of the person asking or get angry.The people asking really may not know, and they know that YOU DO KNOW, and they want the answer from the expert.Part of your job is to educate others. When you are asked why something costs so much , don't get angry. Just inform or educate the person asking WHY it takes time and costs so much. Thats all.Last edited by Donald Branscom; 03-16-2011 at 09:30 PM.Reason: spellingAWS certified welding inspectorAWS certified welder |
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