Repairing cracked weld excavator blade

[liberty2701]

I just got done with a large project and cleaned the excavator undercarriage for inspection. i noticed this crack along the cutting edge weld plus two cracks on the upper bracket. I was going to grind a v in the crack , preheat to 350 and use some 7018 rod. Would this work or is there a better idea?

I also enclosed some pictures of how worn the blade is. I made a post earlier on this wear and was advised to leave it as is. I do have a some 1/2" thick old plow blade that is extremely hard and thought about welding it on and dropping it 1" below the existing worn blade to give a clean new edge. What about this idea?

 

[Oldoak]

Being you cannot grind the backsides of each the cracks, grind the V deep enough, almost all the way through, in order to get 100% weld penetration. Welding with 7018, you there is no need to preheat. Now if you were going to use 8018, then you would want to preheat the area being welded. 7018 will do just fine in your case.

We always would arc-gouge to open up cracks like those. Much faster than grinding. But then that was while doing industrial welding where we had many options available.

 

[liberty2701]

Being you cannot grind the backsides of each the cracks, grind the V deep enough, almost all the way through, in order to get 100% weld penetration. Welding with 7018, you there is no need to preheat. Now if you were going to use 8018, then you would want to preheat the area being welded. 7018 will do just fine in your case.

We always would arc-gouge to open up cracks like those. Much faster than grinding. But then that was while doing industrial welding where we had many options available.

Just curious as to why is no preheat required?

 

[liberty2701]

Being you cannot grind the backsides of each the cracks, grind the V deep enough, almost all the way through, in order to get 100% weld penetration. Welding with 7018, you there is no need to preheat. Now if you were going to use 8018, then you would want to preheat the area being welded. 7018 will do just fine in your case.

We always would arc-gouge to open up cracks like those. Much faster than grinding. But then that was while doing industrial welding where we had many options available.

Just curious as to why is no preheat required? In your opinion should I just leave the cutting edge as is?

 

[Tractor Seabee]

That blade has seen some serious service but worth saving if you do not have to pay for labor. It is a real good project if you like to clean up in prep to re-weld the existing. Only 6010 and 6011 are forgiving on dirty rusty material. The others including MIG need a ground out and shiny all he way prep. I use 6011 a lot for that reason plus it is a deep penetrator. I would weld it out all the way with 6010 or 11. No reason to get a nice smooth flat finish bead. Absolutely no reason to pre-heat.

Ron

 

[dragoneggs]

Newbie here... but pre-heat would only help? Easy to torch it some, right? Just trying to learn here.

 

[liberty2701]

That blade has seen some serious service but worth saving if you do not have to pay for labor. It is a real good project if you like to clean up in prep to re-weld the existing. Only 6010 and 6011 are forgiving on dirty rusty material. The others including MIG need a ground out and shiny all he way prep. I use 6011 a lot for that reason plus it is a deep penetrator. I would weld it out all the way with 6010 or 11. No reason to get a nice smooth flat finish bead. Absolutely no reason to pre-heat.

Ron

Can you explain why 7018 and no preheat is required. I thought the weld needed some flexibility being it was hardened steel on the front of the blade. Thanks

 

[Egon]

Welding on the old plow blade should work. Just extend it enough so there is an angle on the leading edge.

 

[liberty2701]

I just cleaned up and welded up across the whole blade using 6011. I will see if it cracks in the future. I think welding on the new blade will be a project for another day

 

[liberty2701]

Is it actually necessary to use a hardened steel edge for the replacement blade or would 1/2" mild steel suffice?