cast alum vs cast iron

[art]

It is interesting that some feel that a tractor needs crude weight! Weight in the wrong place is a negative as well as too much period! It is unfortunate but from time to time someone asks us to overload a tractor and then they complain of fuel usage and the tractor being unresponsive! There are too many of them being set-up that way and we often find them when people feel the need to replace them. It is important that the tractor has good balance to equalize the traction of the front and rear axles under the loads that the operator has to carry.
It is important that what ever metal is used that when in use the attachments also add to the strength of the unit to endure the load distribution!
We have seen cast of all metals fail when not supported properly for the loads exerted on them! We don't have to go back to far to find manufacturers that have made blunders in mounting attachments like loaders that broke cast iron housings or aluminum!

Many of the manufactures have balance and weighting charts to enhance the use of the tractor for different uses that allow the operator to optimize the feel and usefulness of the equipment.

 

[mcfarmall]

The old Farmall is made out of cast iron and so will be my next tractor. Aside from all the hyperalloy metallurgical questions that no one seems to be able to answer, I'll take a cast iron tractor over a die cast aluminum one any day. No wet spots on my property so weight is my friend.

 

[Egon]

Kinda like trying to figure out if a pound of rock is heavier than a pound of feathers!

 

[sd455dan]

The old Farmall is made out of cast iron and so will be my next tractor. Aside from all the hyperalloy metallurgical questions that no one seems to be able to answer, I'll take a cast iron tractor over a die cast aluminum one any day. No wet spots on my property so weight is my friend.

If possible I would chose Cast Steel in place of All cast iron. If it ever cracks sure makes it easier to weld.

 

[Gary Fowler]

If possible I would chose Cast Steel in place of All cast iron. If it ever cracks sure makes it easier to weld.

Lots of folks misspeak when referring to cast metal. I have yet to find any part of a tractor frame that is not cast steel. I have welded lots of things on cast steel using LH7018 electrodes. NOT so easily done on cast iron.


Lots of heated items are cast iron like wood stoves etc which handle slow heat up and cooling better than cast steel which tends to warp up after many heat and cool cycles.

 

[sd455dan]

Lots of folks misspeak when referring to cast metal. I have yet to find any part of a tractor frame that is not cast steel. I have welded lots of things on cast steel using LH7018 electrodes. NOT so easily done on cast iron.


Lots of heated items are cast iron like wood stoves etc which handle slow heat up and cooling better than cast steel which tends to warp up after many heat and cool cycles.

Right , thought there had been a few threads concerning broken bell housing and transmission cases.

The ones I remember reading all appeared to be cast iron from the welding advice given, most recommended brazing due to the part being made of cast iron..??.

I did have to re weld some cracks on my Ford 3000's front axle assembly and it was definitely cast steel.

 

[mcfarmall]

So what's the diff between cast iron and cast steel?

The main difference between the two elements is that steel is produced from iron ore and scrap metals, and is called an alloy of iron, with controlled carbon . Whereas, around 4% of carbon in iron makes it cast iron, and less than 2% of carbon makes it steel. -source Google.

So how do you tell the difference in the field?

Nyton analyzer. -source I've used one.

 

[mikester]

Cast irons have high carbon content. Steels have low carbon.

Cast irons are easier for casting complex shapes than steels are. Different alloys of cast iron also have different properties and their selection depends on the use you are putting them to. Easier to cast also means they are cheaper to produce.

Grey irons have free carbon or graphite in flake form. Nodular or ductile irons have spherical graphite forms. Compacted irons are in between.

Tap on a grey iron casting and you hear a dull thud. Nodular irons will ring like a bell. You can do a spark test as a quick and dirty check for cast steels in the field.

Grey irons have excellent vibration damping characteristics which makes them excellent for machine bases etc. Nodular or ductile irons can be cast with thinner walls, have higher strength than grey irons and some grades can withstand high temperatures and thermal cycling well. Safety critical parts like steering knuckles, brake rotors etc are made from nodular irons. Exhaust manifolds tend to be made from silicon moly ductile irons because they can be cast with thin walls and have excellent strength and withstand thermal cycling.

Bottom line is you choose your metal alloys based on your desired materials strength, weight, casting complexity and cost to produce a finished product.

Car engines are going towards aluminum because manufacturers want light weight cars so they can get better fuel economy. Older cars used cast iron and nodular iron because it was cheaper to produce. Commercial trucks tend to use a lot of ductile irons. Construction equipment will use ductile irons and cast steels. Motor cycles tend to be mostly aluminum.

If you look closely at homeowner class equipment they tend to be made with die-cast aluminum because they can be made cheaply with very little machining and finishing required. Die-cast aluminum does not handle vibration and fatigue, is softer, and doesn't handle impacts as well as well as ductile irons.

Cheap Chinese made equipment tends to be grey irons because they tend to melt any old garbage they find and as a result have poor metallurgical quality control. If you have poor metallurgical control you will have difficulty making quality ductile irons.

North American/Japanese/European stuff is generally produced with better metallurgical quality controls.

For my tractor I want ductile irons because they are strong and cost effective. Weight is less of an issue. My zero turn uses more die-cast parts.

I avoid homeowner class equipment because they tend to be cheaply made, flimsy construction and have poor durability. That's why I would never buy a Chinese made John Deere lawn tractor at HomeDespot.

 

[goeduck]

Cast irons have high carbon content. Steels have low carbon.

Cast irons are easier for casting complex shapes than steels are. Different alloys of cast iron also have different properties and their selection depends on the use you are putting them to. Easier to cast also means they are cheaper to produce........
........
For my tractor I want ductile irons because they are strong and cost effective. Weight is less of an issue. My zero turn uses more die-cast parts.

I avoid homeowner class equipment because they tend to be cheaply made, flimsy construction and have poor durability. That's why I would never buy a Chinese made John Deere lawn tractor at HomeDespot.

Very informative. Nice write up

 

[Ivan49]

I will take weight anyday over a lighter tractor and I have wet ground. If you want to see the dif between cast iron and cast steel hit it with a grinder for 10 mins or so but expect to turn black from the cast iron. I have machined both. Cast steel if improperly welded with break out like cast iron so we always welded it the samwe as cast iron