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Up Topic Welding Industry / Technical Discussions / D1.5 Heat input averages
- - By jwright650 (*****) Date 05-03-2019 20:46 Edited 05-03-2019 21:35
Ok guys what is the magic bullet to get every pass to fall in line within 10% of the average(minus the root and cap)?
Voltage and Amperage are staying fairly close to each other, but the welder is watching how his passes are filling in and adjusting his travel speed accordingly, which is killing me on keeping this heat input with in 10%.

How do you know before the pass is complete if it is going to be within 10%? How am I going to know the average until I average all of those passes?
If the welder sees that his groove is filling too fast to get an additional pass in that layer he is going to speed up and mess with my heat input. We will be wasting a lot of plate and time trying to hit this magic number...feels a lot like throwing darts at a board hoping to get a bull's eye. I just need to get a completed 30" plate off to the lab so I can help this small fabricator get their CAR resolved and we are running out of time.

My head will look like the top of Al's if I keep pulling hair out :eek:
Parent - - By Shane Feder (****) Date 05-05-2019 00:24
Hi John,
A bit more info on what you are trying to achieve would help.
Never agreed with averages being used for calculating heat input - always minimums and maximums.
As an example
1 x run at 100 amps (welded very slow)
1 x run at 150 amps (welded very fast)
Average is 125 amps
Using 10% of average you have minimum of 112.5 amps and maximum of 137.5 amps so the initial 2 x runs would not comply.

Heat input should always be expressed as a range.
Highest Amps/Volts x Slowest Travel speed is your highest (maximum)  Heat Input
Lowest Amps/Volts x Fastest Travel speed is your lowest (minimum) Heat Input

I may be totally wrong but if your PQR listed 100-120 then the amperage range based on the 10% would be 90-132 amps on the WPS.
If you have been given a single Heat Input based on averages and you are trying to calculate 10% of that then no wonder you are having troubles.
Parent - - By jwright650 (*****) Date 05-06-2019 11:58 Edited 05-06-2019 12:02
Hi Shane,
I'm trying to help a small fabricator qualify a procedure to D1.5. Alot has been added and changed since they qualified their original WPS. They have mis-placed or lost most of the supporting documentation over the years. During an AISC audit they received a CAR due to the lack of supporting documentation. So I'm trying to help them with this and it has been frustrating trying to get this to fall together.

We welded out two 30" plates and neither attempt was successful in getting the fill passes to be within 10% of the average heat input. I watched the gauges like a hawk and making sure those numbers stayed really tight so the only variable that was out of my control was the time it took to travel across the 36" from run off tab to run off tab.
Parent - - By Shane Feder (****) Date 05-06-2019 12:31
If you are trying to qualify a PQR to "validate" a previously qualified WPS would it not be easier to throw the original WPS away and start again ?
Only thing I can suggest is you get a helmet on and have a short stick handy - if the welder goes too fast you give him/her a smack on the back of the head. LOL !
Good luck with your endeavours,
Parent - By jwright650 (*****) Date 05-06-2019 16:02
We threw the old stuff out and are starting fresh.
Parent - - By Jim Hughes (***) Date 05-06-2019 14:58
I have had to qualify PQ's to D1.5 for the State of New York and they are very picky about the 10% rule. What I have done before is have a practice piece (similar to the actual test plate) that the welder can use to weld on and get his/her parameters squared away prior to actually welding on the PQ plate.  I know that sounds fairly elementary, but it has worked pretty well for us. Hope that helps.
Parent - By jwright650 (*****) Date 05-06-2019 16:06
We have welded two plates out hoping one of them would fit inside D1.5's heat input rules.
First attempt we had several passes that didn't fit within the 10% average. Second attempt  we got closer with 6 out of the 11 fill passes making it within the 10% average.
Parent - - By Steelslinger (**) Date 05-06-2019 15:56
Travel speed makes the biggest change to the Heat Input calculations. Amps and Volts don't change the Heat input value hardly at all with the little amount that you would be allowed to change them.

I have a spreadsheet set up that I record all the information of each pass as it happens. That allows be to keep a 'running' average and I can then instruct the welder that he needs to speed up or slow down his next pass.
Parent - - By jwright650 (*****) Date 05-06-2019 16:08
I setup a spreadsheet in excel to calculate quickly once I had the pass timed with a stop watch.

Who in the real world is going to seriously do all of this on a piece that is in production? Serious question.
Parent - - By Steelslinger (**) Date 05-06-2019 16:14
Realistically, nobody.

Technically, the DOT expects the QC or onsite inspector to do that.
Parent - - By jwright650 (*****) Date 05-06-2019 23:03 Edited 05-06-2019 23:12
This shop only does fillet welds, 1/4 & 5/16. Full depth stiffeners get the 5/16 fillets and some other small accessory for mounting the guardrail gets 1/4" fillets and that is it. The only reason I see they need to perform the 30" weld coupon is to get the mechanical testing out of it. We already did the fillet weld soundness tests and macroetch both sizes of fillet welds that they use in production. All of that looked fine.
Parent - - By 803056 (*****) Date 05-07-2019 01:18
Have you tried using a "Bug-O" to control the travel speed?

Parent - - By jwright650 (*****) Date 05-07-2019 09:45
Is that permissible? I would feel like that was cheating, but Yeah, I would think that the Bug-O would take the speed variable out of the equation.
Parent - - By 803056 (*****) Date 05-07-2019 11:30 Edited 05-07-2019 12:13
It is very difficult for a welder to maintain the travel speed welding freehand for the simple fact that it exceeds the limit of what a welder can move his arms easily without changing the angle of the electrode, etc.

There's no prohibition in the standard that I know of. Trying to build muscle memory is pretty trying, so use the mechanical aid to help the welder utilize the correct travel speed.

I guess as an inspector, we don't have the where-with-all to question the code, but you have to wonder where the 10% factor was pulled from. Seems rather arbitrary for a manual or semi-automatic welding process.

Best regards - Al
Parent - - By Shane Feder (****) Date 05-07-2019 12:25
Please accept my ignorance but where is the "average" requirement noted in either D1.1 or D1.5 ?
I only have old editions (2010 & 2008 respectively) for reference but cannot find anything in those two.
Parent - - By 803056 (*****) Date 05-07-2019 13:02
D1.5:2015, clause  5.12. This one of the changes in the 2015 edition: "The heat input for any individual weld pass in a qualification test, except the root and cap passes, shall be within +/- 10% of the average heat input of all the passes in the test."

Best regards - Al
Parent - By jwright650 (*****) Date 05-07-2019 13:16
I know that I can't be the only guy out here fighting with this, that was the reason that I came to query the greatest minds in our field here in this forum.
Parent - By jwright650 (*****) Date 05-07-2019 13:18
Shane the customer had a WPS/PQR written to 2008 and so it has thrown them for a loop trying to  get up to speed with the 2015 code.
Parent - By jwright650 (*****) Date 05-07-2019 13:20
D1.5:2010 touches on some if this, but the tough parts were added in 2015.
Parent - - By jwright650 (*****) Date 05-07-2019 14:40
I keep going back over the changes in 2015 and I  don't readily see a way out of welding out the 30" coupon as shown in Fig 5.1, even though Clause 5.10.1 talks about exemptions for single pass fillet welds. However, I  think the only process exempted is SMAW. This fabricator is using GMAW. Clause 5.10.2 then says that you have to qualify the fillet weld procedure in accordance with 5.12 that Al mentioned using Fig 5.1. Clause 5.10.3 goes into the fillet weld soundness testing for each size of fillet weld that will be used in production and I've already cut and etched those.
Parent - - By jwright650 (*****) Date 05-07-2019 15:04
After reading the Commentary on  Clause 5.10.1 it reads like single pass fillets are exempt and goes on to spell out why the groove weld tests doesn't reflect the same mechanical properties as a single pass fillet weld. Now I'm on the fence about what is required.
Parent - By jwright650 (*****) Date 05-08-2019 15:14
Nope, I'm not testing anymore, unless they go to a multi-pass fillet weld or CJP. I have found enough in 2015 to satisfy my simple mind.
Page xiv,  changes to this edition
Page 89 Clause 5.10.1
Pages 101 Table 5.3 row for Fillet welds, processes All to include GMAW
Pages 386 and 387 C-5.10.1, 5.10.2, 5.10.3.
Parent - - By jwright650 (*****) Date 05-07-2019 13:14
Thanks for your reply Al. I agree that this requirement in 5.12 is a bit erroneous and places a great deal of difficulty on a welder to maintain that consistency. It's been  engrained into the welder to be able to adjust his/her hands to what they are seeing under the shield and now we're making them ignore all of what they have been trained to do.
Parent - - By Shane Feder (****) Date 05-07-2019 22:14
Thanks for the replies guys.
So we have to add a calculator to the tool-kit now ? :confused:
Parent - - By jwright650 (*****) Date 05-07-2019 22:34
.....and a stop watch
Parent - By 803056 (*****) Date 05-08-2019 13:14
They've always been part of my tool "kit".

Up Topic Welding Industry / Technical Discussions / D1.5 Heat input averages

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