Welding up a big hole in thick steel?

I need to weld up about an 1 3/16 hole in 2" thick plate so it can be remachined. The hole got oblonged. I'm going to be using 7018 but aren't sure if I should try and weld down 2" deep using a copper backing plate. I'm worried I might get slag inclusions/lack of fusion going that deep. If I took a thin steel washer, welded the hole shut and put it half way in the hole, then welded it in real good from both sides, should this work? Or is it better to use a copper back up bar and put the weld down 2" and then weld up where the back up bar was? I want to have the most sound repair. Thanks for advice.

I had to do the same thing in 1986. It was a bearing sole plate on a bridge concrete abutment / column. The crew drilling the 7/8 inch holes, (13 of them) in the 2-inch thick plate thought the surveyor was taking too long to get out to the bridge abutment, and felt they could do their own layout. WRONG, they got them half a hole off! Not only was welding a 7/8-inch dia hole up in a 2-inch think plate a challenge, but there was concrete in the bottom of the hole! The state DOT wanted the sole plate chipped out and replaced. Problem was this sole plate had about twenty 2-inch bolts in it attached to another sole plate 3-feet lower. Engineers figured chipping out the entire sole plate would destroy the column abutment! I had to go into a testing facility and take a test to prove I was qualified. The state DOT came up with the idea to drive a 10-GA slug to the bottom of the hole in an attempt to block the concrete from contaminating the weld. I had to weld up two holes, one to be pulled in tension, (which the bolt broke) the other to be UTed.
I used Mig to do this, you can buy tapered gas nozzles, and contact tips for the Tweco Model 4 guns. They do help to see around, but the first 3/4 inch is all by sound, I couldn't even see light. All 13 holes passed UT, and the bridge didn't even fall in the water because of the last few earth quakes. :lol:

Ive welded up tractor drawbars with a carbon rod in the buggered up hole.If you weld it shut you may have trouble drilling it back to size.

Stick welder,
Normally, the guys at our shop would bore out the hole for a plug, weld it in, remachine, leaving as much stock around the perimeter of the plug as we can. Could use a piece of round tube as the plug. That might eliminate the remachining if the ID is close enough for your required specs. I.e. is a bushing or bearing going in there or just a clearance hole, etc. Hard to say without knowing the application.

MIG would be the way to do that.

All I have is a stick welder unfortunately. The machine shop said to use 7018 and they would drill and ream the hole to the proper size. The bracket is for holding the torque arm for the rotary cylinder on my backhoe. The top swing pivot ripped right off and the torque arm was holding a lot of the weight which caused the hole to get oblong. I pressed the bracket fairly straight but the hole is stretched. It's like an adjustable king pin that goes in the hole.

Don't even attempt to run over the slag. Soon as the puddle comes up to the slag, stop, and chip the slag and blow out the hole. It will be slow going, but 1 3/16 inch hole is fairly big. I'd place a 1/4-inch plate over the backside of the hole, and grind it off after the hole is plugged. Do you have a die grinder with round head burrs?

It's a shame you can't borrow a Mig welder! A Mig welder would make life easy on you for this project.

Maybe the 135 Fan will jump in; if'en he don't know, nobody knows. He himself would NEVER ask such a question!!!

This is an interesting, do you have a picture of the piece in question?

Does the king pin rotate or does it just hold it in place?

My comments will be based on the assumption that it just holds it in place.

Personally if it were mine I would ream or drill the hole slightly bigger, then turn a plug out of say 4140 annealed on the lathe and weld it in place then drill and ream for the king pin.

I may also try this…
If the out of round area wasn’t that bad I might elect just to fill in that area and dress it up with a file or rotary tool provide the pin did not rotate.

good example puddles,,how complicated something can become!

poorfarmall1 here's a couple pictures of that bridge. Actually the sole plate was on the other end of the bridge, see the shorter concrete columns, then the gap?


These tubs span that gap, the tubs set on bearings bolted to the sole plates embedded in the concrete columns.

what about broing it true ( wider ).. then turning a pin for the bore, then welding that in?

soungduy

OOOOOOHHH Yes he would GGGG al

That's why I was thinking of putting a thin washer/plug in the middle and hoping to get full penetration from both sides. I might be able to borrow a MIG welder but if I can't, I figured I'd be doing lots of stops and starts to clean the slag out between passes. Maybe I could find a copper round bar that would fit the hole and put it half way up? It's going to be fun for sure but a new bracket from Cat is $371.00. I want to get a sound weld but it's not super critical. I want it as sound as possible though.

There is another way.Cut the whole bad hole out in a square,drill the right size hole in a piece of the same size material to fit the square hole,Bevel it all around and weld it in place with a full penetration weld.No boring,no filling a big hole,and probably will take less time,and its a way to use 7018 where it will probably work right.Where I used to work we used to make ladders with 1/2 thick steel bar with 1 inch holes punched in them and weld the rungs in with 7024 and it would make a real purty plug if you knew how to do it.7018 would probably do it too.However with as deep of a hole as you have you would need to change rods real fast because you would have to change rods at lest 2 or 3 times,You might stick 2 7024s together and have it good and flat and plug it that way.You might want to try it a couple of times first to see what it looked like. basically you start straight up in the middle and keep going round and around and out to the edge and burn it into the edge good, up and out the top and if you need to add to it you have to get every bit of slag out first.
There is a way the 7024 slag looks when you have too much and it tries to squirt out the sides you might have to stop.You have to keep it glowing orange around where you are depositing the weld and go slow enough to where its burning in and fast enough to where its not piling up too much.It will build up a lot of slag out the top,just let it keep building and hopefully you will have a slight crown that you can grind flat.You might have to turn it over and finish that side out good.Maybe not.Im not for sure that way will even work,but I know where I worked they made a machine to weld deep holes like that in place of bolts.It was kind of like a submerged arc welder made for deep holes.Basically the same deal as 7024,except the flux was a powder fed around a wire rather than a wire with powder stuck to it.

There's no advantage to repairing the hole if it's going to cost almost as much as replacing the whole piece. Other than MIG, TIG or O/A there is no possible way to fill the hole up without having to do lots of stops and starts. If you tried to weld over slag or even worse, sub arc flux, you'd have nothing but porosity. In the case of sub arc, I don't think you could even strike an arc on the hardened slag. 7024 has a very heavy slag that would cause nothing but problems besides which it isn't an option. I'm going to see if I can find a solid copper/brass bar that fits in the whole. Then I'll only have to weld down an inch from each side.

The hole is egged out, and they can't bore it out and put a bushing in it?

I dont think you understand.You dont strike an arc on 7024 slag.I even said you have to get every bit of slag out to start again.You can weld 7024 like I said to plug a hole and you dont restart on any slag.If you have to stop for any reason you have to chip the slag and start in the center again,and spiral out to the edge and keep going until you run out of rod.If you can stick 2 rods together maybe you can get most of the hole filled.I would suggest a air hammer to chip the slag as there will be a lot,You have to keep the arc on the steel.Also a submerged arc Like Im talking about uses real big wire and makes an inch wide weld easy.I have no idea where you are or what you have to work with.I already said MIG would be the best.Also a plug could be machined with a bevel on each end and welded in and ground flat as well.I dont see how you would make a plug with straight sides and weld in a piece of metal as thick as that.It would have to be beveled and then you could weld it with either 7018 or MIG.Then it would have to be drilled in the right place.Now As I said,I dont know where you are and what you have to work with.Where I worked it was hard to get a crane and by the time you had filled the hole and sent it back down the line to get it drilled again it would maybe take 2 or 3 days to get it back.Cutting it out and welding in the right sized piece would be a lot faster where I worked.The new piece would be small enough to hand carry it where it was needed and no waiting on the crane. The way to fix a lot of things depends on how fast you need it and what you have to work with.Myself I would drag the closest MIG over there and weld it and then redrill it somehow.The other ideas were just suggestions.Stuff like that is what I used to do for a living.Holes were welded up and redrilled a lot of times.Besides welding I ran a drill there too for a couple of months.I havent seen anybody try and weld a big hole with 7024 0r 7018.I have seen them weld a hole in thinner stuff with 7024 and 7018 both.I think the biggest reason for using a MIG would be the slag issue with 7024 or 7018.Plus I can think of several other ways you could weld it with 7024 that would work too.Put a divider in it and weld just half of it up with 7024 or maybe even a quarter because you have to keep the slag hot all around the top of the weld.If you cut it into thirds and welded the edges in good it would probably work using 7024.Plus,I dont know whether you have a MIG or not.You can also probably just build up the side where its wrong and redrill it.I dont know what a bit that size would cost so maybe its a better idea to fill the whole hole up and start over.You sure wouldnt want to mess up a big bit like that.

You couldn't just start a 7024, or any stick rod, and keep welding till the hole was filled even if you had a 4' long rod. Slag would definately be a problem. I got some real good luck today for a change though. A guy came out to my MX track that was a machinest. I showed him what I had to fix and he said he does hole repairs all the time. He said he could get one of the welders at his shop to fill the hole and he'd redrill it in exchange for about $100 worth of riding privledges. I couldn't have asked for anything better. They have MIG machines where he works and it's a fairly big machine shop.

Why not find a couler with the id size you need. Center it on the plate where the old hole was. Then mark the od of the couler on the plate. Take and cut out the bad. put the couler in the hole and weld it in from both sides.

Everybody has their way of doing things, but for me 7024 would be first on the list of rods[b:89ebe19df2] [u:89ebe19df2]not[/u:89ebe19df2][/b:89ebe19df2] to use in this case. But don't pay any attention to me I'm just a hobbyist welder. :wink:

I'd take your advice in a heartbeat Puddles! I think 7024 would about the worst choice of rod to use as well. I think the slag would be as bad as if you poured water in while you were welding. As it turns out, the right guy came along at the perfect time. That was a 1 in a million fluke. He said it wouldn't be a problem at all. The first machine shop I talked to wanted $100 just to do the hole and another $100 if I wanted them to weld it up! That even seemed pricey to the guy that's going to do it. He figures it should only take about half an hour to do the whole thing. Of course it will have to cool after welding but that's normal. I think the first shop might have had a $100 minimum charge?

I'm sure they could have but it would have cost more. There's not a lot of material around the hole either. That's why the material stretched.

7024, and 7014 have there place, but not down in a hole. You'll spend more time keeping track of the slag. I think we can all agree, you'd be better served to watch the puddle tying into the side wall than trying to dodge the slag. In a tight / small hole like that there is just not much time to lolly gag around!

On another site I just ran a bend test with some 7014, because I've never run any before, and the thread really got going. Trust me I've run at least a hand full of rod in my time. You have to be on your toes when running a 7014 root on a V-groove. The slag has a mind of it's own at times. :lol:

Nothing wrong with that! I've burned a lot of 7024 and lots of guys like to just let it drag on the plate but I find that the slag sometimes does have a mind of its own and affects the bead. I like to hold the rod just high enough so the slag isn't still in contact with the rod. Then the slag can't do anything funny because the force of the arc is pushing it back. Another thing with 7024 is you can't burn it too hot or the bead will have little bumps like blisters in it. For production it's a good rod though and looks real pretty. :wink: Unfortunately some people think because it looks nicer and is easier to use means it's stronger.

Like I was saying,I have no idea what he has to work with.Its been a lot of years ago for me to even run a 7024 rod much less try and plug a hole with it,But If I didnt have a MIG I would use it.I would say that you would have to stop several times and it probably wouldnt work unless you divided it up,but It would probably work.7018 would probably work too.It might be a little faster with 7024.Its not hard to do something like that if youve done it a lot.As long as the hole is small enough where you can get around it you can weld it up.7018 might work better if you stopped after every pass and chipped it.I know you can weld through the slag with 7018 but there would be too much slag real quick.Same with 7024 if it got to where it wasnt really burning in because the slag was too thick.you would have to stop.I dont know if 7014 would work for this or not,maybe.
Good looking welds.
Sounds like 100 dollars worth of riding is a good deal to get it fixed.

7014 and 7024 are essentially the same rods except 7024 has a heavier coating due to more iron powder in it. It has twice the slag of 7018 and would be a PIA to try and fill a hole with. 7024 is a flat and horizontal position rod only because they run at high heat and fast travel speeds. You CAN'T weld over the slag at all with 7024. On multi-pass fillet welds where the steel is hot from a previous pass(s), 7018 can be run over the slag from the bead below the one your doing. Once that layer is done you have to chip the slag before your can do any more passes. The next set of passes, the slag doesn't have to chipped off until that layer is finished. Of course in most applications you wouldn't be doing that small of a multi-pass weld that the piece would stay that hot. Down inside a hole would not work the same.

back in 09 we would use a carbon rod of proper size ,position it correctly in hole and weld around it.if plate is too thick,we would v it out with torch and then weld it up starting from the bottom.I've welded up probably 10 drawbars and hitches this way over the years using hard surface rods.works well,and I think you can still get most any size carbon rod at a welders supply.