Cast Iron

[MasseyWV]

After reading about tractors that have broke in half at or near the bell housing, which is typically made of cast iron or some other unobtanium material, I couldn't help but wonder why it is used instead of steel.

Cast iron is a very strong metal but it is brittle and can crack or break without warning, as evidenced by some tractors breaking in half. Also, cast iron is difficult to weld, thus making repairs impractiical or impossible.

I am no metallurgist but it seems to me that steel would be a much better material to use. Steel is very strong, more flexible, and can be easily welded, thus making repairs much easier.

Engine blocks I can understand, but why do tractor manufacturers use cast iron instead of steel for bellhousings, axles, and other components?

 

[kebo]

Steel would probably be better than cast iron, but it would have to be mostly machined to form up such intricate parts such as a transmission tunnel or a bell housing. The cost to machine such parts would be exhorbitant, which would drive up the cost of tractors significantly. It's much cheaper to make such parts out of a cast metal, then do some finishing machine work to get smooth surfaces, angles, and precise holes where needed. At least, this my take on it from what I know of metal working.

 

[tcartwri]

There is actually no such thing as cast iron. Cast steel is more apt. The alloys can be all over the place to give it different properties.

 

[mostly_gas]

There is actually no such thing as cast iron. Cast steel is more apt. The alloys can be all over the place to give it different properties.

No such thing as cast Iron? That news to the metallurgy world

 

[sandman2234]

After reading about tractors that have broke in half at or near the bell housing, which is typically made of cast iron or some other unobtanium material, I couldn't help but wonder why it is used instead of steel.

Cast iron is a very strong metal but it is brittle and can crack or break without warning, as evidenced by some tractors breaking in half. Also, cast iron is difficult to weld, thus making repairs impractiical or impossible.

I am no metallurgist but it seems to me that steel would be a much better material to use. Steel is very strong, more flexible, and can be easily welded, thus making repairs much easier.

Engine blocks I can understand, but why do tractor manufacturers use cast iron instead of steel for bellhousings, axles, and other components?

Main reason is the cost of manufacturing as was mentioned, but also the cast iron has a property you hit on without realizing. "MORE FLEXIBLE" is not good when it comes to some parts. Cast iron typically has very little bending whereas steel will bend more readily. Even some very minor bending when loading/stressing will equate to problems in the very near future when it comes to bending it back and forth. Using a metal that doesn't give till it is time for it to fail and then overdesigning that part will give you excellent results. Since the parts you mention typically have bearing surfaces and low tolerance part movement designed in them, having a part that the metal moved would most likely not be good. If a transmisson case bent as you loaded the bucket, can you imagine what that would do to the clearance on the gears as they meshed or the alignment of a shaft?
I think the best idea for a continued one piece tractor would be a sub-frame like is usually recommend on a backhoe. I know if I ever put a loader on a tractor, I am going to seriously look at reinforcing it with a subframe.
David from jax

 

[tcartwri]

No such thing as cast Iron? That news to the metallurgy world

not really. :thumbsup:

 

[sandman2234]

Maybe the alloy currently being used to make magnet attracting tractor parts from using a casting procedure can be called the metal in question of the O/P.
David from jax

 

[mostly_gas]

not really. :thumbsup:[/QUOTE}
Yes really. Grey Iron, Ductile Iron, Nodular Iron are NOT steel:thumbsup:

 

[Ford tractor]

After reading about tractors that have broke in half at or near the bell housing, which is typically made of cast iron or some other unobtanium material, I couldn't help but wonder why it is used instead of steel.

Cast iron is a very strong metal but it is brittle and can crack or break without warning, as evidenced by some tractors breaking in half. Also, cast iron is difficult to weld, thus making repairs impractiical or impossible.

I am no metallurgist but it seems to me that steel would be a much better material to use. Steel is very strong, more flexible, and can be easily welded, thus making repairs much easier.

Engine blocks I can understand, but why do tractor manufacturers use cast iron instead of steel for bellhousings, axles, and other components?

huh? Cast iron is in the same class as "unobtainium"?
Cast iron is one of the most utilized structural materials combining
incredible design flexibility, high strength and low cost. Parts that crack, are typically from poor design or the use exceeding the design spec. Backhoes are typically in that category by the way unless a STOUT sub-frame is in place.

 

[jones6780]

Good chart on strength of metals, both cast iron and cast steel.

Modulus of Elasticity, Strength Properties of Metals - Iron and Steel - Engineers Edge

Russell