Maching cast stee/iron

[Garage5.9]

well recently i had taken a warped turbo manifold to the machine shop to have them machine it so it was more true and not so warped. I waited a couple days then finally called and ask about the progress and they said they are not sure if they can machine it because it turns out its cast steel and not cast iron. They said cast steel is harder than iron ? any one know if this is true ?

 

[cnc-me]

Cast steel is usually better to machine than cast iron.
Its also much cleaner.
Cast iron has quite a lot of carbon in it so it can have
hard spots that may require a grinder to remove.

 

[MBeaty]

In general steel is a stronger material than cast iron, but there are some grades of cast iron and some of steel that have similar mechanical properties. Without knowing more specifics of the material it is hard to make an absolute assessment.

Again, in general, many of the objects we refer to as cast iron are grey cast iron. This material has graphite flakes in the grain structure of it which allows it to be machined quite easily with excellent results. There are however other types of cast iron that do not machine very well.

 

[Ign]

I dunno much but I turned two cast steel crankshaft pulleys for Bobcat motors. They cut fine, and yeah, better than cast iron.

I was told if you weld it with 7018 it can turn to a form of carbide which becomes nearly impossible to machine at that point. No experience however.

If nothing else your manifold should be able to be surface ground but the cost may exceed a new manifold.

 

[Steve from Socal]

If it is a high nickel alloy it could be tough to machine with HSS or Stellite, many automotive machine shops used these cutting tools.

Steve

 

[gorilla]

Often the best way to machine an exhaust manifold is with a large belt sander. In my experience they are hard to set up on a mill and often have hard spots that chip the cutters.

 

[Garage5.9]

talked to the machine shop today and they said once they get all of the Al heads out of the way they will set it up and just let it do its thing until its done im assuming.

 

[toolsd]

I can't imagine a manifold being cast steel, that's reserved for things like anvils, crankshafts, stuff like that. Notwithstanding, there isn't a reason to harden it for a manifold, so it shouldn't be. The steel can be either hard or relatively soft, depending on how it's treated. Get it real hot, dull cherry red or more, and let it cool slowly, it'll be annealed and easy to machine.

I believe what they mean is that it's just hard. Which is common if the part is cooled to quickly or certain grades of cast iron. No matter how hard it is, grinding will work. I don't much like the abrasive belt method as the platens on those machines aren't really all that flat themselves, which limits how well they work.

Using carbide should work also, especially with the very little amount of machining required. It is tough to mount them, but it positively can be done. May need to go to a regular machine shop, rather than an automotive machine shop.

Tools

 

[cnc-me]

Often the best way to machine an exhaust manifold is with a large belt sander. In my experience they are hard to set up on a mill and often have hard spots that chip the cutters.

My friend used my 6X48 Delta belt sander to do his 5.4 liter Ford manifolds.
I guess it worked because I never heard back from him.

 

[Vicegrip]

My friend used my 6X48 Delta belt sander to do his 5.4 liter Ford manifolds.
I guess it worked because I never heard back from him.

I am almost embarrassed to admit it but I did the same on a budget race car for a friend. It worked just fine. YMMV.