Cast iron repair??
Cast iron repair??
I did not have any luck with the search feature and I hope this isn't one of those questions that gets asked daily.
I have noticed a couple of "ears??" where bolts go through to hold the finals (or other places also) are broken. Usually missing parts and now have big washers to help hold. Or, some other get by repair
How does one go about repairing these to make a restoration strong and look right?? I will have a transmission case to use as a "donor" of cast.
Is this possible?? I don't have these parts off yet. Just trying to plan ahead.
I have noticed a couple of "ears??" where bolts go through to hold the finals (or other places also) are broken. Usually missing parts and now have big washers to help hold. Or, some other get by repair
How does one go about repairing these to make a restoration strong and look right?? I will have a transmission case to use as a "donor" of cast.
Is this possible?? I don't have these parts off yet. Just trying to plan ahead.
Welding cast iron is as much "art" as science. To repair it, have it just as strong, but not be visible will be tough. Cast iron does not join as readily as steel. I have a cast iron wire that I use in the wire welder that I have had good luck with, but don't know how it would stand up under a lot of stress. Bronze is another alternative, and when done correctly will be strong, but you probably can not dress it down too far if you are concerned about hiding the repair.
Lavoy
Lavoy
Lavoy, I can live with a visible repair as it is something that only "nit pickers" would see. I just hate the look of large washers or missing pieces on an otherwise nice tractor.
I have a wire feed but have never tried it on cast. Also a torch. Using bronze don't you have to heat the whole piece up?? How about with the wire feed?? I have used a cast rod in a DC welder a couple of times.
I have a mill and could make a jig that bolts to the next bolts holes on each side to keep things aligned and flat.
I have a wire feed but have never tried it on cast. Also a torch. Using bronze don't you have to heat the whole piece up?? How about with the wire feed?? I have used a cast rod in a DC welder a couple of times.
I have a mill and could make a jig that bolts to the next bolts holes on each side to keep things aligned and flat.
- Davie Sprocket
- 430 crawler
- Posts: 71
- Joined: Sun Jul 08, 2007 11:37 am
- Location: Leduc Alberta, Canada
If it is a free floating part like a broken bolt flange, then you can weld it pretty easily, but if it is locked say cracked along a piece this is were you get into a lot of trouble. I've had some casings welded and it took the welder a lot of time to do it, but for a broken ear wasn't that bad, an alternative to welding is lock and stitching but this is more for cracks as well. If you google for lock and stitching you will find info as well as cast iron repair.
Good luck and keep us posted your not the only one with some cracked and broken cast iron.
Dave
Good luck and keep us posted your not the only one with some cracked and broken cast iron.
Dave
In a topic that I posted lavoy mentioned spray welding as an option. The complete name for this process is oxy/acetelyne powder (spray) welding. Larger shops can perfrom this process using an arc. Powder spray can be used for many purposes, and is commonly used for crankshaft journal build up. I have seen the oxy/acetylene type used for cast iron repair with amazing results. The preheating of a large area of the casting is not required and the repairs are not as prone to cracking. In one sales demonstration I watched as a flange was reattached to a exhaust manifold then immediately quenched in water. Not only did it not crack, but the finshed weld was strong enough to be considered like new. I myself have made numerous cast iron repairs using the gtaw(heli arc) process. Nickel wire, cleanliness, sufficient preheat and post heat are the keys. There are two types of nickel filler metals( pure and alloy) used for cast iron repairusing gtaw, smaw, or gmaw. One is stronger the other is machinable. In most cases the machinable wire is the better choice. Mark
If the ear is missing that complicates things. I would find steel plate the thickness of the broken ear and use a torch to cut out the correct shape to replace it, then braze this to the casting.
Cast iron really should only be repaired by brazing or stitching. The grain structure is not able to stretch and conform to arc welding repairs like steel does, due to the embedded graphite, so while welding may make the parts "stick," it puts a lot of stress on it in the area of the weld.
Cast iron really should only be repaired by brazing or stitching. The grain structure is not able to stretch and conform to arc welding repairs like steel does, due to the embedded graphite, so while welding may make the parts "stick," it puts a lot of stress on it in the area of the weld.
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- MC crawler
- Posts: 6
- Joined: Sun Nov 04, 2007 7:59 am
welding final drive
I have a large stainless weld on the final drive housing on my 420c, done by an unknown previous owner, and I've often wondered if they just got lucky, or if the composition of the housing allowed itself to be welded. There are different types of cast iron, gray cast used in engine blocks and low stress housings, ductile cast used in C clamps and pipe wrenches, and what's called semi-steel cast iron used in machinery and a lot of agricultural applications. They each require different approaches and so I'm wondering if anyone knows for sure what Deere used for in their final drive housings. There are ways to tell, a spark test will usually identify gray, or more definitively, a look at an etched sample under a microscope.
The idea of using stainless steel welding rod on gray cast iron is a back-woods approach that may or may not work. Nickle is the element that is responsible for the succesful welding of gray cast iron, and depending on the type of stainless alloy used [ there are over 30 types out there] there may or may not be enough nickle to insure success.
If you're going to take the trouble to clean, prepare and weld gray cast iron do yourself a favor and buy pure nickle rod. E-Ni CI [ coated rod] or ER-Ni CI [bare rod for tig]. This is the industry standard for repair of gray cast. They're not cheap, probably over $5.00 a rod, but if you consider your time, they're well worth the money.
The procedure is to vee out the edges, ideally with a sharp chisel. A grinder will work, but gray cast contains a lot of graphite and this will tend to get smeared on the surface. If you find the filler metal rolls off the base metal, it's because of the graphite. I always sear the joint with an oxidizing flame before welding. Let it cool.
Do Not Pre-heat. Pre-heat has it's place in other welding procedures, but not when electric welding cast with nickle. Weld no more than 1/2 inch long beads. Let it cool so you can touch it with your hand. Peening the bead with light blows from a small ball peen hammer as it's cooling will expand the bead and reduce the shrinking stess on the cast iron. Move over and deposit another half inch bead, and so on until it's done.
If this sounds slow, it is, and many welders won't have the patience for this, but this is the established procedure worked out by metallugists after extensive testing, and it works.
You may find that the nickle will not wet the base metal if using the above procedure on exhaust manifolds, especially diesels. This is because after long usage the sulfer in the fuels has migrated into the cast iron and this starts to come out preventing fusion. You can smell it. I have had success in this situation using oxy-acetylene and cast iron rods. These rods are actually cast iron, they are square with a rough cast surface, and brittle.
They were used a lot at one time, but after the evolution of nickle rods they more or less dissapeared and you may have trouble finding them, but this is one application where they are definitely superior. I have repaired at least 50 manifolds without failure.
If the part is operating at under 500 degrees, the geometry allows it, and color match is not a factor, then oxy-acetylene brazing with brass should always be your first choise. It causes no metallurgical changes or hardening of the cast and is always stronger than the original, and in the case of ears or protrusions it's a piece of cake. Vee out from both sides, sear off the graphite, clamp it down, tin it and weld it. The brass stays ductile and stretches until a low temperature, taking the strain off the cast iron.
There are other factors to consider, welding always causes distortion, and the geometry of the part may force enough of the shrinkage stresses onto the base metal to make welding impractical, but a lot of parts are needlessly replaced for lack of the proper technique
The idea of using stainless steel welding rod on gray cast iron is a back-woods approach that may or may not work. Nickle is the element that is responsible for the succesful welding of gray cast iron, and depending on the type of stainless alloy used [ there are over 30 types out there] there may or may not be enough nickle to insure success.
If you're going to take the trouble to clean, prepare and weld gray cast iron do yourself a favor and buy pure nickle rod. E-Ni CI [ coated rod] or ER-Ni CI [bare rod for tig]. This is the industry standard for repair of gray cast. They're not cheap, probably over $5.00 a rod, but if you consider your time, they're well worth the money.
The procedure is to vee out the edges, ideally with a sharp chisel. A grinder will work, but gray cast contains a lot of graphite and this will tend to get smeared on the surface. If you find the filler metal rolls off the base metal, it's because of the graphite. I always sear the joint with an oxidizing flame before welding. Let it cool.
Do Not Pre-heat. Pre-heat has it's place in other welding procedures, but not when electric welding cast with nickle. Weld no more than 1/2 inch long beads. Let it cool so you can touch it with your hand. Peening the bead with light blows from a small ball peen hammer as it's cooling will expand the bead and reduce the shrinking stess on the cast iron. Move over and deposit another half inch bead, and so on until it's done.
If this sounds slow, it is, and many welders won't have the patience for this, but this is the established procedure worked out by metallugists after extensive testing, and it works.
You may find that the nickle will not wet the base metal if using the above procedure on exhaust manifolds, especially diesels. This is because after long usage the sulfer in the fuels has migrated into the cast iron and this starts to come out preventing fusion. You can smell it. I have had success in this situation using oxy-acetylene and cast iron rods. These rods are actually cast iron, they are square with a rough cast surface, and brittle.
They were used a lot at one time, but after the evolution of nickle rods they more or less dissapeared and you may have trouble finding them, but this is one application where they are definitely superior. I have repaired at least 50 manifolds without failure.
If the part is operating at under 500 degrees, the geometry allows it, and color match is not a factor, then oxy-acetylene brazing with brass should always be your first choise. It causes no metallurgical changes or hardening of the cast and is always stronger than the original, and in the case of ears or protrusions it's a piece of cake. Vee out from both sides, sear off the graphite, clamp it down, tin it and weld it. The brass stays ductile and stretches until a low temperature, taking the strain off the cast iron.
There are other factors to consider, welding always causes distortion, and the geometry of the part may force enough of the shrinkage stresses onto the base metal to make welding impractical, but a lot of parts are needlessly replaced for lack of the proper technique
420c
- Stan Disbrow
- 350 crawler
- Posts: 2904
- Joined: Fri Jul 15, 2005 3:13 pm
- Location: Raleigh, NC
Hi,
My dad, the machinist/toolmaker always referred to these final drive castings as 'cast steel', for what that's worth. He was quite the welder, though, working in his brother's tractor dealership as the machinist/parts maker fixing all manner of busted things with the welder and machine tools.
I can do many things around the machine shop, having learned from him, but I decided to follow one of my uncles into the electrical engineering world, so I'm no expert on just what went into the various castings, or just how to repair them.
Stan
My dad, the machinist/toolmaker always referred to these final drive castings as 'cast steel', for what that's worth. He was quite the welder, though, working in his brother's tractor dealership as the machinist/parts maker fixing all manner of busted things with the welder and machine tools.
I can do many things around the machine shop, having learned from him, but I decided to follow one of my uncles into the electrical engineering world, so I'm no expert on just what went into the various castings, or just how to repair them.
Stan
There's No Such Thing As A Cheap Crawler!
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
-
- 40C crawler
- Posts: 11
- Joined: Fri Oct 26, 2007 11:20 am
- Location: Tennessee
There are cast iron rods that are used in stick welding cast iron. Go to your local welding supplyhouse and ask them what they recommend for your application.I own a machine shop and have had an occasion to weld different materials and our welding supplier has always been helpful. Cast iron rods are expensive but worth the cost if you follow the instructions.And not as difficult as you might think with modern rods.
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