I agree. Still, if they are actually handing them a paper and telling them they are now 'Certified' Welders they had better do it correctly. There are many small shops that would take that at face value because they don't know different.
I don't know why they would remove the entire backing bar as they are when they could wait until it was in it's coupon, put it in a vise and twist the small section of backing off with a metric fits all (Cresent Wrench). But, they can do that, and, since they are burning it into coupons that would work better since they would have a problem cutting through the double layer of steel.
Bandsaws are much easier to me. There is a clean edge for checking root and entire thickness before grinding and bending since you are to bend by stretching the side with the most visible discontinuities before the bending process. And you can cut them to exact size with no grinding, just touch up the radius on the corners with a sander. Grinding the torch cut edges tends to push material into the discontinuities making them more difficult to see beforehand. Would not be my first choice.
D1.1-2008, Figure 4.13 (see 4.8.3.1) definitely states "If thermal-cut allow not less than (emphasis mine) 1/8 in to be machined from edges". It is detailed in the figure as 1/8" per side and thus would need to be originally cut at 5/8" in order to remove a total of 1/4" and end up with a 3/8" coupon for bending. Hard to justify doing it otherwise, even for school if you want to show them the "real world" of welding AND testing.
There is no excuse for bending a coupon with no VT on the sample beforehand. It is plainly stated as the process by which testing is done.
One more item, I don't know that you can really make an issue of this but here goes...It states that after the cutting process the 1/8" per side will be removed by 'machining'. There is no distinction in Annex 'K' of D1.1, nor in A3.0 Terms and Defs, nor in the text of the code. However, in A2.4 Standard Symbols, 5.12.2, Contours Obtained by Postweld Finishing, there is a clear distinction between Chipping, Grinding, Machining, Hammering, etc. Can it really be acceptable to grind inplace of machine when the code states "to be machined"? That may be grasping at straws, but it just adds more uncertainty to the quality of the testing being performed.
Have a Great Day, Brent
I've always seen bandsaws used as well, but the bandsaw at this school struggles to cut paraffin, so a 1" steel bar would take hours. I didn't think there was any wiggle room in the code, if it says remove 1/8" from each side, then that is what needs to happen, but my boss and his boss (the CWI) say grinding to shiny metal is all that is needed, as carbon contamination on the surface is what needs to be removed. I was thinking that the HAZ from the cut might cause grain growth, and a subsequent increase in cracking probability, but that is a wild ass guess. As far as "machining" with an abrasive disk, it removes metal in tiny chips, a milling cutter removes it with bigger chips. As long as it's making chips, I think it qualifies as "machining". Of course, some idiot with an angle grinder could hardly be considered a "machinist".
Just goes to show why I don't accept papers from a school. Teachers with CWI's often don't know all the in's and out's of the inspector's actual application of codes and qualifying a welder. What's scary is when they also have an outside inspector whom I presume does this for his income and he doesn't follow through as prescribed.
As Duke said though, it is a school and not a production work line for a contractor/manufacturer.
Have a Great Day, Brent
By Lawrence 
Date 12-04-2012 04:22
Edited 12-04-2012 04:25
If the paper says it's compliant with the code... The work and inspection should comply .. Period.
It's not that big a project to generate a WPS with "hold points" that the students have checked off. Those check off's can have clear reference to criteria or table 6.1... Whatever.
If the instructors you are working with are slack... Set an exampel yourself.
If you look out numerous students on visual, word will get out and believe it or not things will begin to go your way. You can never be criticized for doing a proper inspection from start to finish on a performance qualification.
I set up the hold points on the WPS.. Explain.. Demonstrate each point and the criteria... Then if they miss a hold point it's an automatic failure. They get the point rather quickly.
I also make my students remove the backing bars with Oxy-fuel, carbon arc and plasma gouge... They need to learn how to use the tools don't they? And how to grind to a high tollerance... Grind the bend straps too thin when chasing an indication? Fail They pay attention the second time.
They prepare the straps under my supervision... I choose face, root or which side... We challenge every discontinuity, just like an independent lab will do.
..." if they are actually handing them a paper and telling them they are now 'Certified' Welders"... the students are being done a disservice if the difference between 'certified' and 'qualified' is not explained. One would think that a diligent CWI would want prospective tradesmen to understand as much as possible about the rules that govern their trade. Or maybe he's too busy not performing visual on test plates.
I stand corrected.
Appartenly it is 1/8" per side, not a 1/16" and 1/16".
I apologize for any confusion. Doun't quote the code unless it's in front of you, and it wasn't when I made that statement.
sorry
