Bevel prep for T joint?

[zzvyb6]

Of course, the reason it broke in the first place is because your bolt array produced a hinge at the crack line. A HUGE bending moment from the upward thrust of the wedge. Why not cut off the broken plate, make a replacement and add the holes and bolts in a pattern needed to restrain the stop properly.

If you weld it, the extra bolts are still needed. Otherwise its gonna be a "fool me twice episode".

 

[Cord]

Actually, it broke because the head twisted sideways.

 

[zzvyb6]

But that's not a twisting failure. Otherwise the two pieces would not marry together like your picture shows. And simply welding it back together would take some metal re-forming. That crack was probably expanding from underneath for a while. Even with a twisting moment, a bolt pattern at all corners would likely prevent this.

 

[Tractor Seabee]

Yea, I'm planning to replace it with some 1" plate. This will be a tough repair. Ordered a larger torch tip last night just so I could get through the existing welds.

A scarfing tip may work better or maybe a carbon arc, beings you have a high amp welder.

Ron

 

[Cord]

A scarfing tip may work better or maybe a carbon arc, beings you have a high amp welder.

Ron

I was looking at the those in the catalog, but I've never used, much less seen one. I ended up ordering a typical tip that was bent 30 degrees and was rated for 3".

 

[Rancher Ed]

Cord,
I'm having difficulty picturing what exactly you will be welding from the description and pictures. However, based on your description here are my thoughts.

Beveling your 3/4" vertical member is definitely advisable. If possible I recommend beveling both sides of it equally at ~45 degrees to a point in the center. Beveling all the way to a point will allow you to make a full-penetration weld with reinforcement on each side. This is how lifting eyes are welded onto equipment. Due to the thickness you would obviously have multiple passes on each side but this is a picture of what the cross-section would look like.

If you can bevel both sides equally and alternate which side you are welding on you should have minimal distortion. If you have to weld more on one side of the T than the other the vertical piece will pull toward the side with more weld, and the easiest way to counter this is to allow for the movement in your setup. Pre-heating has many benefits but do not expect it to prevent the vertical member from pulling toward the side with more weld metal. If this is some type of high strength steel you should keep it below 800F but there is no other need to let it cool between passes.

Based on the provided pictures of the fracture I'm pretty sure it failed all in one day. If the crack initiated weeks or months ago and was slowly propagating with each use the old portion of the crack should be darker and potentially show signs of corrosion. As it is the entire fracture face is the same bright shiny color.

 

[Cord]

Thanks, that confirmed what I was thinking. Prepping on the inside might be a bit difficult, but I think I can get it after torching the broken plate off.

 

[Cord]

Got the old brackets torched off. Cleaned up the slag and then torched in the bevels. I bought a grooving torch tip. It cuts terribly, but man it notches beautifully! I made the lengthwise passes on the 3/4 plate to create the bevel. I then cut off the 1/2 reinforcement plate that was on the side. Look at how clean it got the surface! Just a little weld to clean up. No over cutting at all.

 

[jgriffin1720]

Why not use some fresh oven baked 5/32 or 3/16 7018 for this? I would not use short arc solid wire mig for this. It's too thick and too safety critical. If you had dual shield or could get some 90/10 for spray transfer, that would be better. To get the correct fillet size your going to need at the very minimum a three pass fillet weld, probably 5 or 6 passes on the beveled welds, with .045 wire and even with your welder it's gonna be cranked up pretty high. Pre heat needs to be around 350 to prevent cracking and your gonna need to keep an eye on temps between passes. Also let it cool slow, cover it with a welding blanket or something, and I wouldn't do this out in the cold winter air without a big propane torch or a rose bud to keep it warm for a few hours after your done.

 

[Cord]

Well, it took me three full days to do it, but I finished it last night. Ironically, it was 2.5 days of prep for one hour of welding. I have a 300 amp gun and it was getting too hot to hold. The setting I had was right on the transition between globular and spray. If I ran the bead too fast it would switch to spray. Suppose I could have turned up the bolts just a little and keep it in spray, but the setup was working I wasn稚 messing with it.

Had some help come over today and three of us split all day. Not certain just how much we did, but it was enough to fill 8 IBC cages

The attached pics are the hard facing on the wear surfaces.