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Hi everyone. I'm reaching out to you guys for some assistance. On the bottom of a WPS where the welding parameters are located, how does one locate those operating parameters?
Volts, WFS, Travel Speed, CTWD, etc.
I'm trying to write and review some pre-qualified WPS and having a hard time understanding the accurate way of obtaining these values. I'm using GMAW E70C-6M for various thicknesses and positions. Is there a place where one can find this information for the those categories.
Jshot, a good place to start would be the manufacturers recommended welding parameters, and assuming you're working to D1.1, a good start would be to utilize the info in 3.6
Here is an example... Keep in mind that parameters for cored fillers differ from one brand/type to the next.
So you will need to find the data for the brand you use, and it's also a good idea to do some hot-work trials to be sure your equipment dovetails properly with the suggested parameters/stickout etc.http://www.hobartbrothers.com/uploads/pdf/datasheets/FabCOR_Element_70C6.pdf
Thank you, Lawrence. I looked at the Lincoln data sheet and found the volts, amps, but the travel speed is what i'm not sure of now. Any recommendations for the travel speed? Also, I see on your Hobart sheet and the Lincoln sheet has for .045 wire listing the min and max volt and amps, would it be safe to place the 25-30 for the volts area on the wps and then the 195-365 for the amps on the wps? Or should a narrower selection be chosen. I''l take any pointers.
jshot, Re: travel speed
Get your best welder to give you a hand with this...
Get the welding machine parameters set within the mfg's recommendations, then have your welder try a few passes.....use your watch and time the welder for 15 seconds and multiply the distance travelled by 4 and this will give you a distance travelled in inches per minute. Try this several times and get a good average. (can use 20 seconds and multiply by 3, use 30 seconds and multiply by 2....etc)
If you are trying to work out a fillet weld procedure, have the welder run the various size fillet welds that you would need to use in production and work out the travel speed for each size and welding position. Larger fillet welds will be slower, smaller fillet welds will be quicker. Progression uphill(3F) will be slower than travelling along on the flat(1F). Once you get going with this, you will see how it all relates.
If you use the deposition rates from the Hobart sheet I attached.
.045 has a deposition rate of 12.3 lbs. per hour @ 450 IPM
A 1/4" convex fillet weld weighs 0.155 lbs. per foot (Lincoln Procedure Manual)
So 6.5 feet of 1/4" fillet per pound of weld deposited
80 feet of weld per hour (960 inches)
16 inches per minute
Speaking to Voltage and WFS settings for a production WPS.
With .045 Metal Core (for example)
450 IPM (360 amps) can produce fillets on 10ga to 10ga with no burn thru and CJP's to unlimited thickness. There is really no reason for a wide WPS range for welds in the flat and horizontal position.
Allow a reduction *range* to 350 ipm. (300 amps) and you sacrifice almost 3 lbs. of deposition per hour. Which equates to:
19.5 feet less per hour of 1/4" fillet (234 inches) @ 16 ipm. Why do it?
Do the trials on voltage (keeping a tight range of WFS, say 430-450 ipm.) Looking for a spatter free weld with no undercut... Give about a 2 volt range.
This whole notion that welding is a black art and that the welders need to be given a wide range of parameters, even though everybody is working on similar production tasks is one of the worst problems in American manufacturing today. In simple terms; welders are given this wide latitude because management/leadership is not competent to direct them.
If you take these numbers and extend them out to an annual view, it's easy to see that a well run shop can produce vastly more work (profit) for the same amount of effort, with zero capital expenses, just by understanding a few basic welding FACTS.
This is the kind of information presented in the AWS Certified Welding Supervisor (CWS) body of knowledge, and is totally absent from the CWI body of knowledge.
While the CWI carries some prestige, the CWS can actually make a dying operation live.
Thus endith the lesson; you will now be returned to your regularly scheduled programming.
Thank you all for the responses and I feel more comfortable with the situation.
I have one last thing to ask in reference to another active post I read: Can one WPS cover multiple joint types and positions? I have been told if a flare bevel butt is to be welded then we need a WPS depicting that joint. Or if a "J" is used, then we must have one depicting that. A bevel, single or double, and so on.....(Many scenarios) We're only working with one filler metal classification, one wire diameter, etc (Just of course different joints). Can a simple butt joint wps cover these?
If your welders are mushrooms, listing a butt joint with a single V-groove will be sufficient. Such a WPS is exactly why most welders simply ignore them. As most welders will tell you, "The WPS is a waste of paper." Hard to argue with such an assessment.
The welders will quickly assess the WPS as useless as used toilet paper and I would be in complete agreement.
If you need someone to help you develop a WPS, hire a good consultant and use the time as a learning experience.
Best regards - Al
"Looking for a spatter free weld with no undercut"....by Lawrence
Exactly....once you have been in the shop awhile, you can walk by someone welding and tell if they are welding within your procedure or not by the sound of the arc. Loud fireworks, you can count on spending man hours removing spatter. Like Lawrence stated, if you maintain a certain WFS/Amps, you can tune it in with the voltage to be spatter free and no undercut. Spatter is wasted material because it is consuming filler without contributing to and building the weld puddle size.
Travel speed can be a wider variable on a pre-qualified WPS since you aren't normally worried about heat input. If you list the ipm at too tight of a number especially a single number as in '15 ipm' then you have limited your welders as to what they can do in many other aspects and techniques.
Many inspectors will hold you to that with no tolerances allowed. There are cases where that is fine and Lawrence brings out some great application examples of that. But, caution is to be used in making that an across the board statement and practice. The fillet weld example is a good and true picture of knowing and stating volts, wire feed speed/amps, and travel speed to get the correct weld size with the least amount of waste and/or repairs.
Going with too large of a range definitely makes the WPS of little to no importance or practical use as a guide for the welders. If you are going to try to make a one size fits all WPS then don't even bother, just let every man do that which is right in his own eyes.
Now, the code and commentary are clear that there are items that can be combined on a WPS: positions, electrodes, joints, materials, etc. There are many factors that will determine how far to go when grouping items and also when separating and only listing ONE position, electrode, material grade, joint, etc.
There is a lot more do developing a WPS that will be applicable and actually worthwhile on the production floor to guide the welders to the best finished product.
He Is In Control, Have a Great Day, Brent
Great point Brent... I can't believe I missed it in all that blathering :)
Whilst I provided an example of how to calculate travel speed, given a specific required fillet size, wire diameter and WFS; and it's important to know that things like this can be calculated with simple arithmetic and can be verified in trials, Brent reminds us of reality.
Slight gaps in fitup, mill scale, gun angle and many other factors will have an effect on the actual weld size, and volume... And we must never forget that as the weld size increases, travel speed decreases dramatically.
With those parameters listed, a 1/4" fillet travels (calculated) @ 16ipm... Reduce that fillet size to 3/16" and the travel speed jumps to about 26 or 27 ipm... Raise the fillet size to 5/16 and the travel speed is reduced to about 11.
So Calculating your travel speed and verify it with a trial... Then make that bottom number top number the base (top end) travel speed for a given fillet size, and make your bottom (slower) number about equivalent to the travel speed for the next larger sized weld... This will keep any auditor out of your hair.
Or you can calculate your travel speed for you smallest fillet call out for you top travel speed and calculate the largest fillet size for the slowest... The slowest (large fillet) travel speed will also be the likely travel speed for multi pass CJP groove welds. It's a wide range, but there is justification for it.. Unlike WFS and Voltage.
Just remember to keep your travel speed listed in a range on the WPS so that it remains pre-qualified and adheres to Table 4.5  (+/-25%)which is any increase or decrease in travel speed more than 25%. Find a happy median that fits.
This is a different tolerance than WFS/amperage(+/-10%) or voltage(+/-7%)
You have received several good responses to consider.
A couple of responses have included a recommendation to weld several fillet weld samples to see what parameters work best. You have also been told to follow the manufacturer's recommendations with regards to the range for the welding parameters. I agree with those recommendations with perhaps one additional recommendation; perform a break test to verify the welder secured fusion to the root.
Many welders employ a technique that produces the correct size fillet weld, but they fail to properly fuse the root. A couple of quick tests will provide immediate feed back and verify whether the parameters and technique is producing acceptable results or if there is a problems.
Generally, the technique that will produce unacceptable results is when the welder uses a circular movement as they advance in conjunction with a forehand or push technique.
FCAW and metal cored electrodes really need to be set in accordance with the manufacturer's recommendations. Allowing the welder to set the machine by feel or by appearance and sound will result in inconsistent results from one welder to the next. Manufactures use different thicknesses for the sheet metal used to form the electrode and they use different additives to the components of flux. These variations require different parameters to produce optimum results.
The fillet break test is fast and provides immediate feed back as soon as the sample is fractured and the failed surfaces are examined. Incomplete fusion to the root, slag inclusions, porosity, etc. are easily seen if they are exposed on the fractured surface. AWS D1.1, clause 4 includes a figure showing the largest single pass fillet and the smallest multiple pass fillet on opposite sides of the same sample. My recommendation is to only weld one side so you can break the weld. Cut one end off, and a one inch wide section from the middle. Perform a macroetch on the end and center piece and break both end pieces. A twelve inch length provides more than enough length to extract the necessary macroetch samples and fracture samples for evaluation. There is no laboratory expense if you perform the testing in-house.
Butt joints prepared with the appropriate grooves will provide additional information with regards to travel speed, but I really think the fillet welds will provide the most bang for the dollar and time spent.
Best regards - Al
Good point about the break test Al, sometimes we assume too much about the welder's abilities. I have tested welders for other companies where the GMAW welds did not have good fusion to the backing bar and when I cut the coupon straps out the backing bar fell off.
Been there. The interesting part was the plates passed RT. Classic lesson in RT, it cannot differentiate between two 1/2 inch thick plates one on top of the other or a single one inch plate.
And yes, I did fail the welders. Both were welding GMAW-S.
Best regards - Al
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