American Welding Society Forum
When checking our lift on stud gun, we have noticed when the trigger is pressed and lifts the stud, it does so in a way that is not straight back, it kind of goes towards the top when pulled back. I'm questioning this because we have been experiencing arc blow on 3/8" studs. Machine settings (525amps, and 0.33s) any information would be helpful.
Just for kicks turn the machine up to 620a @ 0.33s and see if that helps with your stud welds on 3/8" diameter studs. My welding procedure has the amperage range from 620 to 830 for a 3/8" stud. May not help with arc blow but you may get acceptable results at the stud base.
This is interesting. I was waiting for others to chime in but John and Scott didn't go where I was hoping.
I have never experienced "arc blow" on studs. I have shot and inspected literally thousands of studs and this is new to me.
To make sure we are actually talking about the same thing, can you please further describe said "arc blow"? And, if at all possible, a picture would really be helpful here.
The flash around a shot stud does not have to be a perfect ring with no 'defects'. If you are looking at some splatter and/or porosity in the flash you do not have a problem. Have you checked to make sure you still can bend test them without any failures?
Have a Great Day, Brent
I've shot and have seen tens of 1000's of studs shot and have not experienced arc blow either. I was also thinking that what he was seeing was the flash around the base wasn't perfect and maybe the machine needed a few more amps to get a 360 degree flash.
Brent, I wasn’t sure how arc blow applied to stud welding, so I just attached a link. If the post is referring to a lack of a 360 degree flash, I’ve always just adjusted the ferrule grip, because my experience is that the ferrule is simply not centered on the stud when the trigger is pulled, causing an uneven or unwelded section at the stud base.
Interesting. I have generally seen this when the studs were either tilted too much or there was extra mill scale on one edge that didn't allow for complete flash or at least uneven flash. Had never heard it referred to as arc blow though.
Their solutions make a bit of sense. It would depend upon the reduction in the flash if it was rejectable and thus require correction. Just because a flash is small does not reject the attachment. It must be non-existent or have undercut into the stud to make it rejectable. That or come off with a blow from a hammer.
John's remedy makes sense as well. If it happens too often, up the amps and see if it just wasn't melting off quite enough. Though his suggestion seemed a bit high to me.
Hard to tell since we have not actually seen the OP's pic of the situation.
Have a Great Day, Brent
I agree. A picture would be very helpful. Like John, I’ve shot thousands of studs over the years, but I’ve never heard of arc blow on a stud weld. Another thing I sometimes to to help make sure the weld goes all the way around the stud, is to increase the arc time, which, once the trigger is pulled, Gives the weld a little more time to complete the circle.
What is the minimum and maximum duration of radiography test for IBR joints after completion of welding as well as PWHT also ?
Never seen anyone test shear studs with RT.
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