I'm in the middle of learning SMAW, and I'm wondering exactly how to determine when slag will "burn out" and when it will stay there and cause an inclusion. Any pointers? I know that if you don't clean out the weld very well slag will get into the weld, and that a hot pass is supposed to burn some out, but I'm uncertain where the line is. Obviously if I make a point of cleaning it ALL out I won't have to worry about it, but presumably if mention is made of being able to burn some of it out, I should take advantage of that ability, especially given how long it takes to scrape out every last little trace of slag.
(Assume for the sake of argument that I'm going to be using a wide variety of electrodes and the complete range of amperages and positions, and need to know how to avoid it under most conditions and not just one specific set of conditions.)
Thanks!
This is how my pipe welding instructor (totally old school dude) told it to me: "Grind out all the slag & you never have to worry about it." Sure, you can get a lot of it on a hot pass & some will argue that they never need to grind. Some of those guys probably won't admit that they have had inclusion in some of their "perfect" welds either. Whatever floats your boat. I would always go the extra effort & grind a little, rather than rely on the fact it will just get "burned out" by the hot pass. The last thing you want is to have a cutout & rework after a Radiograph or UT. It could cost you your job, or at the very least, be very embarrassing.
That's my thoughts on it anyways. Do it right, or don't bother doing it at all. Good luck. S.W.
When in doubt, grind it out.
It comes with experience.
There is no exact formula. A minute amount of slag can be "burned out" on the next pass IF you are running hot enough. The key is to get to the point where there is no slag to be burned out after chipping and brushing.
On 6010 root pass on pipe you will need to grind most of the slag out before the hot pass.
If your weld is popping and splattering you are not cleaning enough slag from the previous bead. Your puddle should not look like a bowl of cornflakes either. That is an indication that there are too many impurities in the molten puddle.
It takes time and maybe a failed x-ray or two to find that thresh hold.
i just nok the top off of it if proceder says so if not i just buuf the bead and burn it out , i was always taught a man that grinds all his wagon traks out turns it down because hed be afraid hed burn through therefor trapin slag, but to each his own u just gotta figure out wat works for u
dude just burn as hot as you can,almost out of control but not hot enough were you are getting a lot of buckshot. depending on the aloy depends on the amount of dig you will get out of the rod. for example useing 7018, it is good about digging in and eating out anything that is hidding in there while runnig a bead such as a filler bead if you are running hot enough when you come across some slag it will pop out and you will see it shoot out at you hope this helps
Topic Welding Industry / General Welding Discussion / when will slag burn out vs. create an inclusion
