Hard surfacing

I have some excavator teeth that I need to build up and reshape. Thought I would ask for some advice on the type on welding rod that would be best for this project. Also, although I have never used them, I"ve heard about hard surfacing welding rods. Are they something I should consider for this project and do you weld with them just like any other rod? Any thoughts and advice would be appreciated. Thank you all. Jonathan
 
I would build up the worn tooth with 7018 Then reshape it. I would then put hard face on it stoody 35 works great. There is other hard face rods most likely as good. Normally you don't put hard face on more than one pass thick. It will crack when you put multiple passes to build something up. The heat range should be on the box, you are not looking for penetration so you could run on the low side.
 
I don't mean to imply that the answers you've already received here aren't good, because they are, but this is a case where it might be more fruitful to get your information online directly from the product manufacturers. They know more about their products than anybody else, and this is one of those rare instances where they have no reason to mislead you.

Stan
 
Have you priced new teeth. If you take everything in to account,it might be cheaper to replace them. I do very little hard surfacing. We just replace the teeth.
 
First hardfacing rods aren't designed to build up, just to do what their name inplies and put a hard surface on an object. That said, nearly all hardfacing rods are going to crack wether you use one pass or two. Too, some rods are designed to use in a single pass application and achieve full hardness while some need at least two passes to obtain maximum harness.
 
I've done quite a but of hardsurfacing over the years and hardsurfacing rod isn't designed to use as a build up material. That said, depending on the tooth, many teeth aren't designed to be built up either. Basically the alloy they are made of isn't easily weldible, and if you don't use the right rod, right temps, etc through the process the built up area will break off the first time you put stress on it. In other words so your best bet is probably going to be to replace the teeth. Once you have the new teeth in place then they can often be hardfaced the hardfacing only lays on the surface. To be honest though, with the cost of the hardfacing rod/wire/etc, (the last rod I used was around $8-$10 per rod) and the time spend doing it, it's usually cheaper in the long run just to get new teeth unless your running a HUGE machine.

That said, most welding mfgs that offer hardfacing rod also have filler rod that they recommend for use under thier hard rod. Personally everything I have worked on thus far that needed buildup, etc was origionally mild steel and I used a regular 7018 rod/wire to do the buildup work. Once I got things like I wanted them I then layed either one or two layers of hardfacing, depending on the rod type and/or wear resistance needed in that particular area, to get the protection wanted.

Hope this helps. Wayne
 
Only though I would have is... replace the teeth. If it's some odd tooth that is unavailable or expensive... spend your time remodeling the shank to take another more readily available tooth. That can be done with 7018.

Rod
 
Wayne pretty much covered it. If your set on screwing with them for half a day, build them up with 7018, then run your hard surface. I really think you should call Iron Peddlers, or whoever you have locally and price some teeth. You couldn't hire me to wool with a bunch of excavator teeth all day when you can buy them for $60 to $80(for the big ones)knock em on and be done. That being said I'm sure there are a lot of things I do to save $ that people shake their heads about!
 
Bucket teeth can be hardfaced BUT it all depends on what the teeth are made of. 7018 for build up is a waste of rod. It will mushroom. Use build up rod if the teeth are worn and hardfacing rod for the final pass for wear protection. You will most likely need to preheat the teeth to 300 or 400 deg's, weld them, then heat them up even more and slow cool them in an oven. It would be better to try on a new tooth.
 
NCWayne, What I posted worked for me. I have a 24"bucket on a Case 580 that has the corner of the bucket built up with hard face and I see no cracks. Kind of a triangular area. The welds butt against each other. A one pass build up. To have sharp hard teeth the best repair would be to replace the teeth.

I have a 36" bucked on a Bantam that I can't weld on near the teeth unless I preheat to 400 degrees and maintain the heat while welding. I want to put a cross hatch pattern there with a little hard face.
 
I know this is not what you asked for but some of it apply's to your question and some of the rest might be helpful also.
This could be someones opinion, or he could know what he is talking about.

Lots of welders figure that a E7018 etc. has 70ksi TS so its stronger than the base material. Strength has nothing to do with it. Using welding / joining electrodes for buildup is a bad idea because E7018s, E71T-9 cored wires etc have little compressive strength. Take a MIG, E7018 weld and beat it with a chipping hammer. Now try that with a proper alloy buildup deposit

This can cause any hard facing over the so called buildup to spall off as the buildup mushrooms flat . This might not matter for if your blade sees ZERO pounding / impacts but this is seldom the case. Bottom line you are wasting time with E7018 etc.

ROLLERS - you need a "Metal on Metal" product. This is typically a martensitic tool steel. Typically in the industry ( ie Caterpillar specs ) calls for products approximately 40Rc to 55Rc . If you need more than 3 layers of hard facing to bring part to proper dimension then use a "build up" product for the first few layers .

Typical products would be Lincore 40 or Lincore 55 ( Not lincore 50 ). These are LA Martensitic products

Now for the 2nd most common wives tale on hard facing: Hardness is the important spec. Truth is it does not tell you everything. Because of this do NOT walk into a welding supply store and just ask for XX Hardness

For example: all the following popular hard facing products can be 55Rc

1. Low Alloy Martensitic - great for metal to metal sliding wear ( wheels / idlers / gears / shafts

2. Austentic Manganese - great for severe impact. You find these products on railway frogs , build up prior to hard facing , hammer parts

3. Chromium Carbide - probably the most common . This is typically what you think of when you think hard facing. Very good performance with abrasion ( dirt / sand / wood ) . Poor impact resistance, somewhat poor metal to metal performance

Dozer Blade

Best choice for this application is a chromium carbide in the 50Rc range . Lots of people also go up to the next level 60Rc for blades but it will not take impacts very well. No need for a buildup / buttering layer if you only need 1/4 "

Typical product would be Lincore 50 ( NOT Lincore 55 ) or Lincore 60 or equivalents . These are chromium carbide products

I also assume your welder knows to only hard face the one side of a cutting / bucket edge ( so it will continue to self sharpen ).

Don't even think of using MIG / E7018 etc
 

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