High Alloy Irons? 7

[SaxonViolebce]

I'm not a Metallurgist and I'm looking for a high alloy iron that melts at low temperatures and is mold friendly like regular cast iron, but has noticeably more tensile and compressive strength than most cast irons--preferably close to the strength of the better chrome moly steels like 4330.

I'm looking for something that can be cast in a small shop, or a backyard foundry--which pretty much rules out casting steel.

I read that most high alloy irons require high temperatures to cast and are not particularly mold friendly--but the word "Most" implies exceptions.

Does anyone know of such an excepton?

Saxon Violence--yes look at the funny typo in my handle.....

 

[cloa]

Look for casting alloy steels- even wikipedia list some.

 

[swall]

You might consider austempered ductile iron (ADI). I believe the castability is similar to standard ductile iron. There is a post casting heat treatment process that has to be applied, however.

 

[arunmrao]

Backyard foundry practice will exclude all ferrous alloys.You may look for aluminium bronze material.which is amenable to heat treatment.

_____________________________________
"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year

 

[TVP]

I agree with swall, ADI will have the properties that you desire. How well-equipped is your backyard?

 

[SaxonViolebce]

Allright.

I don't have a casting set-up at present, but several of my friends do.

They generally cast Aluminum, a few Cast Brass or Bronze and one fellow has been experimenting with Aluminum Bronzes--I forget the specifics, but he got the first batch of Aluminum Bronze due to some sort of "Accident".

I have studied the books of C.W. Ammen in some detail--but I checked them out from the library, and don't remember all the specifics.

At any rate, Ammen felt that casting Iron in the Backyard or Small Shop was quite feasible, but that Steel was not within the reach of the Home or Small Shop Foundry because it required a few hundred degrees more heat, and because it wasn't what he called "Mold Friendly"--i.e. Without pressure, centrifugal force or some other expedient, that the molds wouldn't fill completely--except as a fluke.

Steve Chastain also has several books on home casting--including Iron, but I haven't got to read them yet.

If you're still not convinced that Backyard Iron Casting is Feasible, "U" Tube and the Internet in general, is full of counter-examples.

My interest is in casting Firearms parts to be used in modern Smokeless Firearms. Conventional wisdom has it that Cast Iron is too brittle for most such applications...

Ammen mentioned High Alloy Irons in passing, in one of his books.

I looked some of them up online and some of them compare favorably to some of the Chrome Moly Steels in Strength and Ductility...

But then some research uncovered the fact that Most High Alloy Irons are just as much, or even more trouble to get good castings from than Steel.

So I was looking for the Exception.

Been wanting to set up and do some lost wax and/or lost foam casting with Aluminum and Bronze for some time--More for Sculpting Purposes than from any utilitarian objective--but my funds are chronically limited--I'm on disability.

At any rate--On the Gun Building Forums, I generally suggest and do design work and then others build and test.

Anyway, there has been some interest in casting Iron parts and/or using Cast Iron parts, and I was trying to find a suitable High Alloy Iron.

Thank You all for your kind answers so far.

Saxon Violence

 

[swall]

I have a couple of comments. For melting cast iron, compared to melting aluminum, you are double the temp (2400F vs 1200F for aluminum). That is a big hurdle. Yes,one can build a backyard cupola and melt iron, but you can't control the chemistry because you have no way to check it.Casting gray or ductile iron in small cross sections as would be found in firearms parts is not practical, as you will have a major problem with chill (aka white cast iron). For your application, I think you would be better off buying a mill, like a Bridgeport and machining parts out of bar stock.

 

[redpicker]

As the responses indicate, you are not likely to find a material that you can cast with a backyard set-up that will be capable of capable of withstanding the detonation loading experienced with modern smokeless powders. Not that it can't be done, but just that there are much cheaper ways to achieve the desired ends. swall's suggestion is spot-on, IMO, since you don't have to deal with a lot of the problems associated with casting and can hold better tolerances. Unless you volume is large, the different in costs aren't going to be that great. If your volumes are large, you can just go to a commerical foundry and let the experts deal with the problems.

rp

 

[berkshire]

Saxon,
For the kind of casting you are wanting to do, you might do better to look at an induction melt furnace to handle the kind of alloys you really ought to be looking at for the firearms parts you want to make.
I do not know how much money you have available, but this kind of furnace would handle small parts of the kind you say you want to make. in a much safer manner.
B.E.

http://www.ebay.com/itm/15KW-30-80K...261?pt=LH_DefaultDomain_0&hash=item2c5df512dd

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor

 

[ornerynorsk]

Your best option may be to befriend your local investment casting shop. You can easily carve or otherwise produce a wax pattern, which is very low cost, to produce a one-off, and have your man at the investment foundry do the shell and burnout, and actually pour a high quality alloy of your choosing, which you cannot feasibly do in a backyard foundry due to the investment required, if you'll pardon the pun.
The cost will be trivial compared to trying to do a hobby ferrous foundry and expecting any kind of quality out of it.

As a side note, I have a great deal of experience in producing ordnance components, and I would be very cautious about using home-brew castings. Remember China's "great leap forward"? It's difficult to put a price on an eye or a face, or worse.

Good luck in your projects.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.