James H
I recently had a friends weld get rejected by xray for a concave bead. Repaired it, reshot it, and it came back rejected for IP. Two times in this last year I've heard this. Both times, same example. Is it just a bad xray tech or is it a change in the rules today?
Paul W Cameron - CWI
A friend eh?
Let me preface this by saying, "I'm no RT Guy." but, a concave bead in a radiograph could easily mask Incomplete Joint Penetration (IP).
A concave bead will appear darker (because it's thinner) than the base material around it when viewed in a radiograph. Once that concave bead is repaired (adding more weld [making it thicker then base material]) the area that was once dark is now light and any IP would be clearly visible.
Great Question!
PWC
https://www.facebook.com/PaulWCameronCWI
Wednesday, November 4, 2015
WPS from Multiple PQRs?
Hey Paul,
How does one support a WPS from multiple PQR's?
NeilHow does one support a WPS from multiple PQR's?
I've used multiple PQR's on a single WPS many, many, many times. When creating a WPS in manufacturing for GMAW I may want the WPS to cover all the electrode diameters (0.035, 0.045, 0.052) and wire feed speed (WFS) ranges that can be run. A typical ER70S-6 WPS could take me 9 PQRs (3 dial. x 3 WFS ranges). That was common for me as a Welding Engineer.
Equally…
When I qualify a single PQR I'll write as many WPS's from it as I can. Example: I qualify a Bevel Groove with a PQR, I'll also write a WPS for a V-Groove, a U- or J-, all the PJP's I can and Fillets. I try to get as much “Bang For My Buck” as I can.
PWC
Wednesday, October 28, 2015
Pre-Heat & Interpass Temp
Hey Paul,From your experience, what is your preference when it comes to measuring the temperature of your PQR's?
At current I have access to 7 different rated tempilstik's, but that doesn't sound like a reasonable arsenal to do the job....or is it?
The IR Pyrometer I have is unreliable at best (as well, no calibration records).
If anything, I'm intrigued by the digital contact pyrometers out on the market. Specifically the Estik looks good, though the 2% tolerance for each displayed value is a bit concerning in the upper limits.
As always, thanks for your insight to age-old questions for us newbies!
Neil
The thing about the Temp Stix is that they are considered the “accepted” method (no controversy), especially when dealing w/Governmental agencies (Army Corp of Eng, DOT…).
Honestly? I use my IR gun to determine which TempilStik to use. Sounds weird, I know.
If I can prove to myself that my IR gun is accurate (often dependent on surface condition) I’ll use its readings, but if I’m the least bit concerned, I turn to the TempilStik.
Here’s how I’ll write a PQR:
Pass
1: Greater than 125 / Less than 175Pass 2: Greater than 175 / Less than 225
Pass 3: Greater than 225 / Less than 300
Pass 4: Greater than 300 / Less than 500
Kinda
messy, but I don’t know a better way to do it and it’s never been
questioned. In fact, when they see the ranges they almost automatically
know I used a TempStik and don’t question it. I use to have a contact pyrometer and would spend a lot of $$$ keeping it calibrated. After going into biz on my own I simply wrote a calibration procedure that stated “Place probe in ice water (50% crushed ice/50% water) let stand 10 min. Insure temp reads 32 deg F +/-5%”. That always worked (right up until I lost it).
Hope that helps.
PWC
Tuesday, September 29, 2015
WPS & PQR for Dummies
Hey Paul,
I'm reading up on the proper procedure and practices for developing a WPS and PQR, my question is, do you know of any resources that give a sort of 'WPS & PQR For Dummies'.
At current I'm reading through section 4 of D1.1, and taking notes as to what is required. The process we'll be qualifying is an in house change (bevel angle, and a slight change of amperage and travel speed.) that will be implemented into production.
From my limited perspective I'll be writing down the proposed values on the PQR, send it out for testing, if it comes back with a passing marks, I'll used that information to create a WPS.
However, on the PQR forms we have here, there is a line for "Governing WPS"...something about your seminar mentioning "Which comes first, WPS, or PQR" comes to mind, however I'm unable to to more than remember that idea.
Any help on the how-to is much appreciated! And also, do you have some sort of donation or fund in your name? I feel guilty asking for your assistance without some way to pay you back. If you've any ideas, let me know!
Thanks again!
Neil
Hey Neil,
WPS & PQR for Dummies… I like that.
You may find AWS-B2.1 helpful (https://pubs.aws.org/p/1245/b21b21m2014-specification-for-welding-procedure-and-performance-qualification).
Start by writing a “Preliminary WPS” (This could be considered a “Governing WPS”). This isn’t a real, qualified WPS, it is simply a list of what you’d like your final WPS to look like. Write each of the essential (and non-essential) variables, as you would like to see them. Then work backwards to figure out what PQR(s) you’ll need to qualify them (notice, it could be several).
Starting with a Preliminary WPS helps keep you on track and keeps you from making the common mistake of finishing all your testing and concluding with an, “Oh Crap!... (insert problem here)”. Problems like, “I should have used a Group II steel.” Or “I should have dropped the plate temperature to 50 degrees before starting the root pass (or fill pass).” Or “What was I thinking using a 4 in. pipe?” Or “I should have used a square groove.” You get my drift.
Once you have a Preliminary WPS, break down each variable and ask yourself, “What do I need to do to achieve that?”
Chances are your finished WPS will have greater ranges than your Preliminary because you’ll be working with real data.
As for your specific need (bevel angle, and a slight change of amperage and travel speed). You may find that your original PQR already qualified the joint and parameters to within the ranges you are shooting for. If so, you simply have to revise, or write an additional WPS. If not, just go through the steps I laid out above.
This line kinda creeps me out, “I'll be writing down the proposed values on the PQR, send it out for testing, if it comes back with a passing marks, I'll used that information to create a WPS”.
That sounds a little, just-throw-it-over-the-wall-ish to me. Let me break it down…
You’ll be:
• Writing down the proposed values
• Taking them to the Welder/Technician for feedback
• Observing, measuring and documenting as those proposed values are utilized
• Determining visual acceptance
• Sending the weldment out for NDE and destructive testing
• Reviewing the test results for compliance
• Using your collected data to develop a WPS
You have to be the one insuring every step was followed. You’ll need to wear the welding helmet to insure technique was correct. You’ll need to insure the final weldment met the acceptance criteria before NDE/Destructive testing.
And finally (and most important) yes, I have a GoQuenchMe campaign that runs continually. You show up in my part of the country or I show up in yours and you have to buy the first round. I believe in keeping it simple.
Cheers!
PWC
I'm reading up on the proper procedure and practices for developing a WPS and PQR, my question is, do you know of any resources that give a sort of 'WPS & PQR For Dummies'.
At current I'm reading through section 4 of D1.1, and taking notes as to what is required. The process we'll be qualifying is an in house change (bevel angle, and a slight change of amperage and travel speed.) that will be implemented into production.From my limited perspective I'll be writing down the proposed values on the PQR, send it out for testing, if it comes back with a passing marks, I'll used that information to create a WPS.
However, on the PQR forms we have here, there is a line for "Governing WPS"...something about your seminar mentioning "Which comes first, WPS, or PQR" comes to mind, however I'm unable to to more than remember that idea.
Any help on the how-to is much appreciated! And also, do you have some sort of donation or fund in your name? I feel guilty asking for your assistance without some way to pay you back. If you've any ideas, let me know!
Thanks again!
Neil
Hey Neil,
You may find AWS-B2.1 helpful (https://pubs.aws.org/p/1245/b21b21m2014-specification-for-welding-procedure-and-performance-qualification).
Start by writing a “Preliminary WPS” (This could be considered a “Governing WPS”). This isn’t a real, qualified WPS, it is simply a list of what you’d like your final WPS to look like. Write each of the essential (and non-essential) variables, as you would like to see them. Then work backwards to figure out what PQR(s) you’ll need to qualify them (notice, it could be several).
Starting with a Preliminary WPS helps keep you on track and keeps you from making the common mistake of finishing all your testing and concluding with an, “Oh Crap!... (insert problem here)”. Problems like, “I should have used a Group II steel.” Or “I should have dropped the plate temperature to 50 degrees before starting the root pass (or fill pass).” Or “What was I thinking using a 4 in. pipe?” Or “I should have used a square groove.” You get my drift.Once you have a Preliminary WPS, break down each variable and ask yourself, “What do I need to do to achieve that?”
Chances are your finished WPS will have greater ranges than your Preliminary because you’ll be working with real data.
As for your specific need (bevel angle, and a slight change of amperage and travel speed). You may find that your original PQR already qualified the joint and parameters to within the ranges you are shooting for. If so, you simply have to revise, or write an additional WPS. If not, just go through the steps I laid out above.
This line kinda creeps me out, “I'll be writing down the proposed values on the PQR, send it out for testing, if it comes back with a passing marks, I'll used that information to create a WPS”. That sounds a little, just-throw-it-over-the-wall-ish to me. Let me break it down…
You’ll be:
• Writing down the proposed values
• Taking them to the Welder/Technician for feedback
• Observing, measuring and documenting as those proposed values are utilized
• Determining visual acceptance
• Sending the weldment out for NDE and destructive testing
• Reviewing the test results for compliance
• Using your collected data to develop a WPS
You have to be the one insuring every step was followed. You’ll need to wear the welding helmet to insure technique was correct. You’ll need to insure the final weldment met the acceptance criteria before NDE/Destructive testing.
Cheers!
PWC
Wednesday, September 9, 2015
"Common Sense" not always That common
Hello Paul,
I was hired into the quality group at a company alongside three other CWI's last October. I'd been asked to do a lot of paperwork type activities until this last July when they needed
that fourth CWI on the floor.
I seem to have put the floor into shock... for example: for inspecting parts to the tolerances on the drawing and writing a nonconformance when it's out of that tolerance range. The other inspectors had been trying to convince me to apply "common sense" to let the parts through anyway, even if that meant the associated paperwork doesn't line up with what the physical part is. I'm still the same person I was when I came through the code clinic, you can guess how the workplace has become increasingly hostile towards me yet again.
I write to ask two quick questions to verify if my thought process is correct if you have a moment:
1. Detailed vs. fit-up tolerances. The code and chatter on the AWS forum eludes to fit-up tolerances applying to the as detailed one. So if detailed gave me +10 degrees, fit-up would give an additional 10 degrees - stacking the two together. I thought I distinctly remembered from the code clinic that the tolerances do not stack, but that both apply to the original, 45 degrees for example. So the max. would be 55 degrees end of story. I am not able to find the support in the code for that and was hoping to double check my memory on that.
2. Starts and stops of intermittent welds. It seems that the D1.1 exception for filling a crater to the full cross section outside of the intermittent area has been taken to the level that the code doesn't apply outside of the intermittent length. Doesn't it still say we should have complete fusion, and smooth transitions - not worms at the start and stop of those?
Just thought I would check in to make sure I'm not getting off base here.
Thanks,
Jessica P
Hey Jessica,
Let me get right to answering your questions...
When it comes to “AS Fit-up” vs “As Detailed” tolerances, during the seminar I will always emphasize, “For the purpose of this test, do not stack the tolerances.” I’ll then go on to say, that may happen in life, but do not do it for the purpose of this test.” CWI’s should never use the “As Detailed” tolerances... only the engineer/designer of the part/joint should. Let me give you some examples:
1.) A Designer/Engineer calls out a B-U2a with a 45 deg Groove angle. The shop floor/Welder/CWI can apply the “As Fit-up” tolerances ONLY and the Groove angle can now range from 40-55 degrees.
2.) A Designer/Engineer calls out a B-U2a with a 55 deg Groove angle (he/she applied the “As Detailed” tolerances). The shop floor/Welder/CWI can apply the “As Fit-up” tolerances ONLY and the Groove angle can now range from 50-65 degrees.
3.) A welding symbol calls for a 30 degree V-Groove on a Butt Joint. The shop floor/Welder/CWI can apply the “As Fit-up” tolerances ONLY and the Groove angle can now range from 25-40 degrees.
4.) A welding symbol calls for a 35 degree V-Groove on a Butt Joint (engineer applied the “As Detailed” tolerances). The shop floor/Welder/CWI can apply the “As Fit-up” tolerances ONLY and the Groove angle can now range from 30-45 degrees.
All those scenarios are perfectly acceptable for that joint type. The Designer/Engineer has one type tolerance they design within, and the shop floor/Welder/CWI have a different tolerance they work within.
Now let me give you some scenarios that DO NOT WORK:
5.) A Designer/Engineer calls out a B-U2a with a 45 deg Groove angle. The shop floor/Welder/CWI applies the “As Detailed” &“As Fit-up” tolerances and the Groove angle now ranges from 40-65 degrees.
6.) A welding symbol calls for a 30 degree V-Groove on a Butt Joint. The shop floor/Welder/CWI applies the “As Detailed” & “As Fit-up” tolerances and the Groove angle now ranges from 25-50 degrees.
The shop floor/Welder/CWI should never stack the tolerances on their own. Again, one set of tolerances is for the Engineer/Designer, another is for the shop floor/Welder/CWI.
Clear as mud, eh?
As for the intermittent fillet weld...
The crater can remain unfilled (weld is undersize) as long as the crater falls outside the required weld length. All other acceptance criteria have to be met for the entire weld length (including the crater). So unacceptable contours, unacceptable undercut, unacceptable porosity, cracks, overlap in the crater would still render the weld “Unacceptable”.
As for your work environment...
Working with other CWI’s can, at times, get challenging. Like Welders, not all have the same skill set.
I took a position once and was over 5 CWI. In my first week I found that all Welders were qualified with FCAW but 75% of the welding was with GMAW. I called each into my office to ask about this. The responses were pretty lame, “That’s what we’ve always done.” “You can’t change things around here.” “There really no difference.”
Don’t Be That Guy/Gal! Stick to the requirements and intent of the code, and when there’s a disagreement don’t argue, “Put your finger on it”. Better to have integrity then a stable job (I’m sure some would not agree with that line). My unstable work history has worked well for me.
I hope that helps. Hang in there, you know this shit.
PWC
I was hired into the quality group at a company alongside three other CWI's last October. I'd been asked to do a lot of paperwork type activities until this last July when they neededthat fourth CWI on the floor.
I seem to have put the floor into shock... for example: for inspecting parts to the tolerances on the drawing and writing a nonconformance when it's out of that tolerance range. The other inspectors had been trying to convince me to apply "common sense" to let the parts through anyway, even if that meant the associated paperwork doesn't line up with what the physical part is. I'm still the same person I was when I came through the code clinic, you can guess how the workplace has become increasingly hostile towards me yet again.
I write to ask two quick questions to verify if my thought process is correct if you have a moment:
1. Detailed vs. fit-up tolerances. The code and chatter on the AWS forum eludes to fit-up tolerances applying to the as detailed one. So if detailed gave me +10 degrees, fit-up would give an additional 10 degrees - stacking the two together. I thought I distinctly remembered from the code clinic that the tolerances do not stack, but that both apply to the original, 45 degrees for example. So the max. would be 55 degrees end of story. I am not able to find the support in the code for that and was hoping to double check my memory on that.
2. Starts and stops of intermittent welds. It seems that the D1.1 exception for filling a crater to the full cross section outside of the intermittent area has been taken to the level that the code doesn't apply outside of the intermittent length. Doesn't it still say we should have complete fusion, and smooth transitions - not worms at the start and stop of those?
Just thought I would check in to make sure I'm not getting off base here.
Thanks,
Jessica P
Hey Jessica,Let me get right to answering your questions...
When it comes to “AS Fit-up” vs “As Detailed” tolerances, during the seminar I will always emphasize, “For the purpose of this test, do not stack the tolerances.” I’ll then go on to say, that may happen in life, but do not do it for the purpose of this test.” CWI’s should never use the “As Detailed” tolerances... only the engineer/designer of the part/joint should. Let me give you some examples:
1.) A Designer/Engineer calls out a B-U2a with a 45 deg Groove angle. The shop floor/Welder/CWI can apply the “As Fit-up” tolerances ONLY and the Groove angle can now range from 40-55 degrees.
2.) A Designer/Engineer calls out a B-U2a with a 55 deg Groove angle (he/she applied the “As Detailed” tolerances). The shop floor/Welder/CWI can apply the “As Fit-up” tolerances ONLY and the Groove angle can now range from 50-65 degrees.
3.) A welding symbol calls for a 30 degree V-Groove on a Butt Joint. The shop floor/Welder/CWI can apply the “As Fit-up” tolerances ONLY and the Groove angle can now range from 25-40 degrees.
4.) A welding symbol calls for a 35 degree V-Groove on a Butt Joint (engineer applied the “As Detailed” tolerances). The shop floor/Welder/CWI can apply the “As Fit-up” tolerances ONLY and the Groove angle can now range from 30-45 degrees.
All those scenarios are perfectly acceptable for that joint type. The Designer/Engineer has one type tolerance they design within, and the shop floor/Welder/CWI have a different tolerance they work within.
Now let me give you some scenarios that DO NOT WORK:
5.) A Designer/Engineer calls out a B-U2a with a 45 deg Groove angle. The shop floor/Welder/CWI applies the “As Detailed” &“As Fit-up” tolerances and the Groove angle now ranges from 40-65 degrees.
6.) A welding symbol calls for a 30 degree V-Groove on a Butt Joint. The shop floor/Welder/CWI applies the “As Detailed” & “As Fit-up” tolerances and the Groove angle now ranges from 25-50 degrees.
The shop floor/Welder/CWI should never stack the tolerances on their own. Again, one set of tolerances is for the Engineer/Designer, another is for the shop floor/Welder/CWI.
Clear as mud, eh?
As for the intermittent fillet weld...
The crater can remain unfilled (weld is undersize) as long as the crater falls outside the required weld length. All other acceptance criteria have to be met for the entire weld length (including the crater). So unacceptable contours, unacceptable undercut, unacceptable porosity, cracks, overlap in the crater would still render the weld “Unacceptable”.
As for your work environment...
I took a position once and was over 5 CWI. In my first week I found that all Welders were qualified with FCAW but 75% of the welding was with GMAW. I called each into my office to ask about this. The responses were pretty lame, “That’s what we’ve always done.” “You can’t change things around here.” “There really no difference.”
Don’t Be That Guy/Gal! Stick to the requirements and intent of the code, and when there’s a disagreement don’t argue, “Put your finger on it”. Better to have integrity then a stable job (I’m sure some would not agree with that line). My unstable work history has worked well for me.
I hope that helps. Hang in there, you know this shit.
PWC
Friday, August 7, 2015
Essential and non-Essential Variables... they can make ya nuts
Dear sirs, I have a doubt about WPS (Weld Procedure Specification) by API 1104 - 2013. For me is not clear if “is outside diameter an essential variable in wps api 1104”, because of in 5.3.2.4 say “The ranges of specified outside diameters (ODs) and specified wall thicknesses over which the procedure is applicable shall be identified. Groupings are shown in 6.2.2 d) and 6.2.2 e).”, and in 5.4 is not included as an Essential Variables.
Thanks regards
Rafael
Rafael,
Essential and non-Essential Variables... they can make ya nuts.
We're often familiar with Essential Variable (those variables that, once changed beyond specific limits, require re-qualification of a WPS.), but what is a non-Essential Variable?
These variables may not show up in a table or list telling us what are allowable variations but they are equally important when writing your WPS. I often find them left off of WPS's and that only leads to confusion when customers, inspectors or Welders try and interpret or apply your WPS.
When a non-Essential Variable is changed no additional testing is required, but the WPS needs to be changed to reflect the new variable.
Some examples would be:
*Base materials - Although base material Groups can be Essential, the individual material types are considered non-Essential. You completed a WPS of a specific material and it qualified you to within a Group. If you want to change (or develop new) your WPS to reflect a different material within the Group
it is simply a matter of paperwork.
*Joint Type - Once I qualify a specific joint type that test qualifies a large number of joint types. I only need to change my paperwork to reflect a different joint design. (You can now see where a single PQR can qualify a large number of WPS's.)
*Electrode extension - As a Welder I can vary current by as much as 50 amps by simply changing my stick-out.
*Electrode type - (GTAW)
*Technique - Can I weave? Can I whip? Am I allowed to oscillate? All should be addressed.
It surprised me, that Diameter is not be an Essential Variable per Section 5.4 of API-1104. But listing it on the WPS is required.
“5.3 Welding Procedure Specification
5.3.1 General
The welding procedure specification shall include the information specified in 5.3.2 where applicable.”
So thickness IS an Essential Variable but Diameter is considered a non-Essential Variable. Both must be listed on the WPS.
Good Question, Good Luck,
PWC
Thanks regardsRafael
Rafael,
Essential and non-Essential Variables... they can make ya nuts.
We're often familiar with Essential Variable (those variables that, once changed beyond specific limits, require re-qualification of a WPS.), but what is a non-Essential Variable?
These variables may not show up in a table or list telling us what are allowable variations but they are equally important when writing your WPS. I often find them left off of WPS's and that only leads to confusion when customers, inspectors or Welders try and interpret or apply your WPS.
Some examples would be:
*Base materials - Although base material Groups can be Essential, the individual material types are considered non-Essential. You completed a WPS of a specific material and it qualified you to within a Group. If you want to change (or develop new) your WPS to reflect a different material within the Group
it is simply a matter of paperwork.
*Joint Type - Once I qualify a specific joint type that test qualifies a large number of joint types. I only need to change my paperwork to reflect a different joint design. (You can now see where a single PQR can qualify a large number of WPS's.)
*Electrode extension - As a Welder I can vary current by as much as 50 amps by simply changing my stick-out.
*Electrode type - (GTAW)
*Technique - Can I weave? Can I whip? Am I allowed to oscillate? All should be addressed.
It surprised me, that Diameter is not be an Essential Variable per Section 5.4 of API-1104. But listing it on the WPS is required.
“5.3 Welding Procedure Specification
5.3.1 General
The welding procedure specification shall include the information specified in 5.3.2 where applicable.”
So thickness IS an Essential Variable but Diameter is considered a non-Essential Variable. Both must be listed on the WPS.
Good Question, Good Luck,
PWC
Tuesday, August 4, 2015
"Scare a moose, scare a moose, will you do my fan Van Gogh"
Paul
I find myself rejecting a lot of welds. I don't want to fail them and find out that I misinterpreted something. When there is undercut in small amounts throughout the length of the weld I'm still not clear on what they mean by "...in two inches up to 12 inches..." (AWS-D1.1, Table 6.1(7)) so I find myself pretty much disregarding the 1/32nd undercut rule, unless the weld is less than 2 inches long. And I just use 1/16.
David N.
All right, here we go...
Table 6.1 (7), Undercut:
"shall not exceed 1/32 in. except...Shall not exceed 1/16 in. for more than 2 in. in 12 in." (artistic liberties taken liberally)
So, undercut that is not more than 1/32" is acceptable. Period! Also, undercut greater than 1/32" that does not exceed 1/16" and it's accumulated length comes to 2" or less is also acceptable.
Example 1: You're looking at a 3" weld. It's got 1/16" of undercut (depth) for 2" of its length. It's acceptable.
Example 2: A 3" weld is part of a 3 on 6 intermittent fillet weld. Imagine 3 of those fall with in 12". One 3" weld has undercut and the undercut is 1/16" (depth) for 3/4" (length). Another 3" weld is undercut at 2 places. The undercut is 1/16" deep for 3/4" and again for 1/2" of length. The last 3" weld has 1/32" for its entire length. These 3 welds falling with in the same 12" of a joint length would be acceptable (Total length of undercut greater than 1/32" deep equals 2").
Now my head hurts.
PWC
Ahh... finally it makes sense. Now I'll have to read it until it's burned into my brain. I never put it together that they were talking about intermittent welds. I wonder if everyone else assumed I understood that, or if they don't know either.
Thank you! You have saved me much self-doubt!
David N.
No, no, no... I simply used intermittent welds as an example. If you had a weld that was 8" long, the same rules would apply.If it had undercut its entire length that did not exceed 1/32" it's acceptable. Along that same weld, at one location the undercut is 1/16" deep for 1/4", then 1/16" deep for 1/2", then again for 1", then again for 1/4", that weld would still be acceptable. (as long as the individual undercuts greater than 1/32" but not over 1/16" do not total more then 2" of length in any 12")
Again, my head hurts.
PWC
Holy crap! I understand even better now! So the length they are talking about is how far along the weld the undercut runs. That is the biggest part I wasn't grasping before. That's so simple... And now quite embarrassing. No wonder nobody could explain it to me, it should have been obvious. Every time I read about the two inches, I was thinking it had something to do with the length weld, not the length of the undercut portion.
I guess I am finding the downfall in studying by myself! I couldn't get past my initial understanding. Kind of like when you learn the words to a song incorrectly, and even after you find out the correct words, you still sing them wrong out of habit... Okay, fine. Maybe it's nothing like that!
David N.
That is Exactly what it's like.
"Scare a moose, scare a moose, will you do my fan Van Gogh"
PWC
I find myself rejecting a lot of welds. I don't want to fail them and find out that I misinterpreted something. When there is undercut in small amounts throughout the length of the weld I'm still not clear on what they mean by "...in two inches up to 12 inches..." (AWS-D1.1, Table 6.1(7)) so I find myself pretty much disregarding the 1/32nd undercut rule, unless the weld is less than 2 inches long. And I just use 1/16.
David N.
All right, here we go...
Table 6.1 (7), Undercut:
"shall not exceed 1/32 in. except...Shall not exceed 1/16 in. for more than 2 in. in 12 in." (artistic liberties taken liberally)
So, undercut that is not more than 1/32" is acceptable. Period! Also, undercut greater than 1/32" that does not exceed 1/16" and it's accumulated length comes to 2" or less is also acceptable.
Example 1: You're looking at a 3" weld. It's got 1/16" of undercut (depth) for 2" of its length. It's acceptable.
Example 2: A 3" weld is part of a 3 on 6 intermittent fillet weld. Imagine 3 of those fall with in 12". One 3" weld has undercut and the undercut is 1/16" (depth) for 3/4" (length). Another 3" weld is undercut at 2 places. The undercut is 1/16" deep for 3/4" and again for 1/2" of length. The last 3" weld has 1/32" for its entire length. These 3 welds falling with in the same 12" of a joint length would be acceptable (Total length of undercut greater than 1/32" deep equals 2").
Now my head hurts.
PWC
Ahh... finally it makes sense. Now I'll have to read it until it's burned into my brain. I never put it together that they were talking about intermittent welds. I wonder if everyone else assumed I understood that, or if they don't know either.
Thank you! You have saved me much self-doubt!
David N.
No, no, no... I simply used intermittent welds as an example. If you had a weld that was 8" long, the same rules would apply.If it had undercut its entire length that did not exceed 1/32" it's acceptable. Along that same weld, at one location the undercut is 1/16" deep for 1/4", then 1/16" deep for 1/2", then again for 1", then again for 1/4", that weld would still be acceptable. (as long as the individual undercuts greater than 1/32" but not over 1/16" do not total more then 2" of length in any 12")Again, my head hurts.
PWC
Holy crap! I understand even better now! So the length they are talking about is how far along the weld the undercut runs. That is the biggest part I wasn't grasping before. That's so simple... And now quite embarrassing. No wonder nobody could explain it to me, it should have been obvious. Every time I read about the two inches, I was thinking it had something to do with the length weld, not the length of the undercut portion.
I guess I am finding the downfall in studying by myself! I couldn't get past my initial understanding. Kind of like when you learn the words to a song incorrectly, and even after you find out the correct words, you still sing them wrong out of habit... Okay, fine. Maybe it's nothing like that!
David N.
That is Exactly what it's like.
"Scare a moose, scare a moose, will you do my fan Van Gogh"
PWC
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