Can broken cast iron be "welded" stronger than original?

By specialists of course.

I've seen the "stitching, but not sure if that's gonna be useful.

The center section casting on a 4 WD tractor broke in two. OOPPS!

Loaders in combination with heavy rear ballast will do that.

Seems to be a hard to get part... "furr'in make"

Sure with the right stuff and procedures, not cheap, al-state or stoody rod is 200/lb how much can you afford?...Phil

A couple grand from the initial response... I'm planing on 3k when it's done.

Do you have anyone in mind? I've only got "internet references? for those who put cooling fins back on Harley jugs, or build up damaged engine heads.

This application is NOT one of those two.

The casting will be too big and heavy to weld i think, it will have oil ingress to it as well which will give porosity to the weld if your not careful to cook it out.

The best way is oxy welding cast with a cast rod and proper flux.

Sure you can weld it with nickel powder or electric arc nickel rod but due to the large mass it will take the heat out easily and you may get local cracking due to it being cold.

Source a tractor wrecking yard for a replacement is best i think or even cast a new one if feasible using the old one as a pattern.stick it together enough to hold hell even mig weld it ( weld goes dead hard though) to hold it in and put filler over it to fill defects only has to hold for moulding. ( depends on what's inside the casting)

as stated your application is severe use and may need a heavier casting anyways since the initial one broke. ie make it thicker in those areas and or rib it/ and or change the mix go for nodular iron instead of cast iron.

as for harley jugs etc heads they are small parts but cast welding is difficult even for small items but those guys would know how cast welds.

We have success welding CI. Put nice chamfers on pre-heat weld using nickel 99 rod the get it into vermiculite right quick and leave there for 24 hrs.
If you have the room an are worried about strength of the weld. You could drill some holes before the pre heat weld on both pieces. This way you could sister some 1/2" steel on either side.
My .02 cents.

Let me know what ya'all think.

You will get it welded,but alignment will be out,and it will need to be corrected on a horizontal borer,or very large mill......incidentally ,is it a Chinese tractor......several of them have broken when a truckie used the winch on the tilt to snug down the tractor.

CalG said:

By specialists of course.

I've seen the "stitching, but not sure if that's gonna be useful.

The center section casting on a 4 WD tractor broke in two. OOPPS!

Loaders in combination with heavy rear ballast will do that.

Seems to be a hard to get part... "furr'in make"

Click to expand...

What you are asking is a very broad question kind of like can a piece of metal be drilled.
First you have to determine what the composition of the casting is? Some mfg such as the older caterpillar housings you can pre and post heat and cats recommended process is 7018.
Other thick sections you need to stud them and weld them.
But first thing is you have to get it cleaned best way is a oven, a lot of auto machine shops have cleaning ovens. Then determine what kind of materials you are dealing with. The materials will determine your procedure and filler materials.
You are almost sure to have some machine work on bearing bore alignment after..
You don't say what kind of box or tractor so I have no idea on cost
But as a example we repaired a gear box for a processing plant aprox 40" x 50" cracked and had 4 shafts 8 bearing bores ran right at 8k. A huge amount is in the machining after, the bearing bores are already to size so each one has to be sleeved or built up then re machined.
If you can find one I would go that route it will save you a lot of time and money.
There are several shops that specialize in just this kind of repair if you can't find one in your area let me know and I can give you a few names.
Not knowing your motorcycle guy I can't say he can or can't but there is a lot more involved than just filling a Crack.

Its not worth the candle.

gbent said:

Its not worth the candle.

Click to expand...

That's what I'm thinking.

All comments are appreciated. I'm not even starting to consider doing a weld repair myself. Closest I've come is brazing up a broken three cylinder Cat header pipe that fit in the BBQ grill ;-)

The Italian casting (may be sourced just about anywhere in Europe) is not heavy or large. A couple hundred pounds tops. A meter long. Obviously the section is too thin, It broke! ;-) (4-6 mm)

Likely the precision is nothing of great concern. It's not broken through any bearing pockets. About the same as narrowing any solid drive axle. Just that there is no steel to weld to.

News should start coming back this next week on replacement availability It's a popular tractor, just not in North America. SL&H, now D-F.
A used unit would be fine, with me, but shipping from Portugal or Romania or... might be an issue. There may be some hope of finding something in California. I need to look back through some misplaced references.

I need to come up with a supporting truss so the failure doesn't repeat. Lots to think about.

Welding cast can be a crap shoot, I do it fairly often on machine castings. it takes a good v groove, preheat, welding small sections at a time to avoid overheating the cast, peening each weld, and a slow cool down in a fiberglass blanket or bucket of sand. even then you might hear it let off a disheartening crack sound while cooling. you'll also find that you can do everything right and then randomly get a weld with craters in it, most likely from some contaminant that has sank into the cast over the years. However, I am usually successful enough to consider it before buying or machining a new part. If you plan on machining the part after welding it, use a 99ni welding rod.

Sounds like a subframe is in order as well.

sounds like its scrap metal now.

Resolution!

I got a call back. The piece is in stock and available.

$815 plus $120 freight delivered from Europe! . About two weeks transit time estimate.

Sounds VERY GOOD TO ME! I gave the order for a factory new replacement the go ahead!

We will see how much of all that holds true ;-)

I wonder if it will come painted? ;-))

No welding required! But the transfer the differential hardware and setting up the ring and pinion will be part of the repair.

I'm optimistic!

Glad you have an acceptable solution. For reference purposes, the way I would fix that casting is to bevel the break to a 1/8" to 1/16" land, fixture to hold evrything straight. Build some kind of enclosure aroiund it, of bricks, sheet-metal... of the part is basically a spacer, or tube-with-flanges, I would run a pipe through the middle like a spit for rosting a whole pig, as part of the holding fixture. Supprot the "spit" outside the enclosure.

Slowly and UNIFORMLY preheat with charcoal/wood/propane, to 800-1200 deg F. Open a window in your enclosure to weld through. ENiFe 55. Weld half and inch and peen while cooling, turn the pig and weld half and inch elsewhere. When all welded, close up the furnace, let it get uniormly hot again, then let fire go out.
You will feel pretty well cooked yourself.
Come back tomorrow and tear the setup down. I always tel the customer that the part WILL warp and need re-machining, but often it does not if the welding was well-distributed and i kept the heat pretty uniform.

It will be as strong as new...which was not strong enough

WAG I would charge .$200-$400 for the job

In your spot I might consider making a new one out of steel ..a tube and flanges. Then maybe the next failure will be bolts pulling out.

Sub-frame.

Good description of the way I've done it in the previous post. And for such an item, based on personal experience I'm guessing there's no way it would not distort enough to need remachining. The preheat and maintained heat are very important, as is the very slow cooling. Both of those ensure no cracking and that the parent and weld metal will be ductile after cooling. A diff/gearbox is in need of pretty precise bore alignment and shoulder squareness. It's a good thing that you got the replacement instead. I wouldn't attempt this repair unless it was an unobtainium antique gearbox or something. Too expensive.