Does anyone know if the Bevel Gear Housing is plat steel, cast steel, or Cast Iron? I have noticed some hairline cracks near bolt holes on the transmission side of the casing and curios if it's something that can be welded.
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Bevel Gear Housing metal type on Cat D6B
- Thread starter Sam1734
- Start date
As it turns out, the housing is actually plate steel, I conducted some test on the surfaces. One tell tell sign was a punch test. Plate steel when using a punch makes a sharp burr, and cast "gray" iron doesn't. Cast iron may leave a burr, but is easily swept away.
Welder Dave
Senior Member
You can do a spark test and cast steel will cut with a cutting torch too. For welding I think you'd want to preheat a couple hundred deg's. before welding and use 7018. Grind a little past the cracks to make sure they don't go further than first thought. You could drill holes at the ends of the cracks but if everything is ground out and fully welded should be good. Peening the welds is also a good idea. Check for loose bolts or something that may have contributed to the cracks. Cast steel doesn't normally crack but on a dozer anything is possible.
Now that you mention loose bolt, One crack is spanning from one bolt that doesn't protrude through the housing as the others do. But, I did have hairline cracks on the top housing cover also like the machine had been in some major jolt. However, I did grove, and grind those cracks with success using fluxcore wire. The reason for fluxcore, was simply because strength wasn't my concern as much as sealing the housing up.
Welder Dave
Senior Member
What type of flux-core and did you preheat? A flux-core wire could be similar to 7018 but if it was just a general purpose self-shielded flux-core the repair may not last long. It would be like putting a Band-Aid on when you needed stitches. Keep a close eye on it.
Yes sir, it was self shielded, but every single crack seemed to only be running across a bolt hole. I know I will end up having to re-tap the threads, but so far no cracks have developed in the new welds. I also didn't have any cracking and popping after the welds were completed like I had before on a exhaust manifold years ago. Also I think I forgot to mention. This entire case/housing is constructed by welding the internal components, and walls together rather than a one cast construction. based on my observations, center punch test, and grinding grooves on the hairline cracks on the top plate, I feel it is 1/2-3/4 inch plate steel. But I still want to be certain before I go any further with the weld process.
I apologize, I forgot to mention, I did not preheat, it tends to stay rather warm in Alabama most of the year, with rare cold winters reaching 10-19 degrees. On average 30-48 degrees in winter.
Welder Dave
Senior Member
A couple hundred deg's. preheat on thicker steel and/or larger pieces prevents cracking on cooling. It's called a quenching affect and is the same reason you don't cool welds with water. The mass of steel acts as a big heat sink. If other parts of the case are factory welded it would be an easily welded grade of steel. An exhaust manifold would be cast iron and with the carbon from exhaust is one of the more difficult things to repair. You could be OK but keep an eye on all your repairs and the area around them. If cracks return you have to take some extra steps to do a proper repair. Usually it's best to bite the bullet and do the repair properly the first time to save headaches down the road.
Thanks Dave, I appreciate this. I would have swore it was cast but when I open the case to change the steering clutches, I was surprised to find factory welds in every connecting point of the case. What threw me for a loop and confuse me was the interior only of the case had a appearance of cast, but from what have read, that is actually a coating similar to rhino liner to help prevent corrosion. I have no intentions of putting it back together until it is in as perfect working order as possible. And as you say, it's much better to fix it right the first time because honestly, removing the ROP, seat, and tank isn't something I want to tackle again anytime soon.