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Up Topic American Welding Society Services / Certifications / stud PQR
- - By ctacker (****) Date 03-15-2008 04:10
I have a job coming up shooting studs on AR400 plate and this being my first stud job would like to get it right the first time. there is no code given in the contract docs but it is for large earthmoving equip. so i'll guess D14.3
I dont have my codebook avail till monday and what i remember from D1.1 i need to shoot 10 studs(threaded) and torque them. do I torque them till they fail and record the result
or just torque them to the specified torque thats given for the size of stud to be welded? 
Is it possible to see if the stud mfg. has a PQR and use that and only need to test the first 2 each shift?
I would appreciate a brief walkthrough of this process.
Thanks
   Carl
Parent - - By aevald (*****) Date 03-15-2008 04:48
Hello Carl, I will be following this thread as you have raised my curiosity with this one. Many years ago I did a considerable amount of work with this material. We were using it for wear plates on coke conveyance systems and associated machinery. When they punched holes in this at that time they would heat the areas to be punched to cherry and punch them while hot. Once one of the operators missed a hole and in his rush to complete the part he failed to heat this spot before punching, the punch exploded and all that happened to the plate was a powder type mark where the hole should have been. He was also fortunate to not be injured. I would be interested to know if there are any sorts of preheats or post-heats related to stud welding to these parts. Keep us informed Carl. Best regards, Allan
Parent - By ctacker (****) Date 03-17-2008 15:02
Looks like no ones biting on this one. the code is D1.1. if anyone has welded studs to this material i would be interested in hearing from you!
Parent - - By ncdotcwi Date 03-15-2008 12:58
I worked with this material in a structure shop around 1995 that used the D1.1 for welding procedures, etc.  The material served as an abrasive liner in a distribution chute for a coal handling system at a power plant.  The design called for the material to be stitch welded 3-12 with no weld 3 inches from each corner, as I recall.  Through trial an error and many failures, we came up with a procedure to weld the material using 310 ss with absolutley no preheat, which was the only way to prevent cracking of the weld at the toe adjacent to the AR400.
Parent - - By swnorris (****) Date 03-17-2008 16:46
Isn't the AR400 a greater than 100 ksi steel and beyond D1.1 criteria in that regard?
Parent - - By ctacker (****) Date 03-17-2008 18:06
Yes, I didn't think about that. seems our salesmen are just that, salesmen.
the stud sales place said they weld just like mild steel, no preheat and same settings. I am mainly concerned with what testing i need to perform to get a pqr written.
as far as i know, i need to test ten studs to failure. and make sure they dont fail in the haz or the weld.
then test 2 studs to per shift but not to failure. am I right on this?
Parent - - By swnorris (****) Date 03-17-2008 19:16
If you follow D1.1 you're correct.  Ten test studs.  All ten are torqued to destruction.  If there is no failure in the WELD ZONE, the procedure is qualified. 

Test two studs per shift, or any change in the set up with regard to stud gun, timer, power source, stud diameter, gun lift, plunge, welding lead length, or any amp change greater than 5 %.

Please let us know the results.
Parent - - By ctacker (****) Date 03-17-2008 22:04
Thanks Scott,
I Just wanted to be sure i was doing it right. Sounds like i am if I can still follow D1.1 on this one.
So that brings up another question, If the Engineer says D1.1 Can I use D1.1 even if its greater than 100ksi steel. or do I need to Follow B2.1 and weld 15 studs with 5 bends,5 torque and 5 macroetch?
Parent - - By waynekoe (**) Date 03-18-2008 01:44
Are you sure that shooting the studs is the way you want to go. I just had a vision of what would be the end result when these two steels meld together. You may have a more suitable result with stick or hard wire. Just a thought.
Parent - - By ctacker (****) Date 03-18-2008 04:37
try telling that to management. i have also wondered about the haz becoming brittle, but i am no metallurgist by any means and the only way i can be sure is run a PQR. according to our stud supplier a few companies around have no problem with that  material and shooting.

thanks for the input.

    Carl
Parent - By swnorris (****) Date 03-18-2008 10:21
Carl,

If the EOR says you can follow D1.1, you can certainly use it.  The EOR has the authority to invoke whatever criteria he/she deems necessary on a project.  However, if you have legitimite concerns, you need to convey those concerns to the EOR.  The fact of the matter is this: An EOR isn't a supreme, know all being, and a fabricator has a practical knowledge that is not taught in college which he gains on his day to day experiences.  An EOR can benefit from this knowledge, so feedback from the fabricator is a very important part of the process.  A project is a team effort between design, fabrication, and erection, and everybody's input is needed to make it a success.
Up Topic American Welding Society Services / Certifications / stud PQR

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