Die Casting Steel - why not?
Die Casting Steel - why not?
(OP)
We are unable to get a satisfactory answer to why steel/iron is not, or cannot be, pressure cast with permanent molds. It can be gravity cast, as I understood, into cooled copper molds. Does the high temperature required make an injection system too short lived, or are there properties of the steel that would be lost in die casting?
It seems to me that die casting steel would be a valuable foundry service for producing large quantities of strong parts-if the prices were even remotely near those for die casting the lighter metals, e.g. zinc, Al, Mg, wouldn't that make more sense than forming/machining/welding steel for certain products?





RE: Die Casting Steel - why not?
RE: Die Casting Steel - why not?
Some small parts weighing a few grams have been attempted in steel. But gray iron castings are processed by die casting process.
RE: Die Casting Steel - why not?
The permanent molds currently used for gravity casting steel, which include refractory metals and some sort of water cooled copper(?), could they be cooled more, to allow a higher production rate? Which could eventually justify the use of pressure to fill the mold?
Is sand casting the main method for getting near net shapes in steel?
I appreciate your help with these questions; I am trying to get a better handle on why certain manufacturing processes work well and others don't.
RE: Die Casting Steel - why not?
RE: Die Casting Steel - why not?
Conventional sand casting is the only method available now to produce steel casting.(Investment casting technology is there for making small and complex parts.)
RE: Die Casting Steel - why not?
The only question left then, which isnt precisely metallurgical: what to do when you want a strong, intricate part?
Is the answer: Just run costs on A) redesigning with the stronger Mg or Al alloys and the tooling (die cast) versus B) design for multi part welding/machining with steel parts but no significant tooling (not die cast).
From a prototype standpoint, it seems safer, and many orders cheaper, to make a steel prototype.
How big is the net-shape steel casting industry? Most local foundries just do bronze, al...
RE: Die Casting Steel - why not?
To develop a prototype sand castings are a lot cheaper and faster. Locate some small foundry in your area who may do it. Or else in India you can contact kasc@satyam.net.in. This foundry can easily handle your enquiry.
RE: Die Casting Steel - why not?
Good Luck in your search for a sound and cost effectve casting
RE: Die Casting Steel - why not?
RE: Die Casting Steel - why not?
You should definitely investigate investment casting or countergravity casting (commonly called the Hitchiner process). Steel can be cast into components with wall thickness down to ~ 2 mm. Use the following link for more information:
http://www.hitchiner.com
RE: Die Casting Steel - why not?
An interesting alternative we have found very sucessful is MIM. Metal Injection Molding. Metal powder (stainless or whatever)is combined with a plastic like material and injected into molds. The product is then baked to remove the plastic and HIPed (Hot Isostatic Pressed) to strengthen the product. Many stainless steel surgical tools are made this way and we have found it a cheaper way of producting a complicated near net shape.
RE: Die Casting Steel - why not?
Investment/ceramic shell does look like it can produce the detail necessary, especially Hitchiner's process. Time is reduced by gang-molding the parts. How long does it take, does anyone know, to go from wax to pour?
What kind of pressure is used in regular die casting? Would the pressure just explode a typical refractory plaster/ceramic mold?
arunmarao: I have read that graphite crucibles introduce iron into ferrous castings; would the same apply to molds? Regardless, sounds like a valuable process.
RE: Die Casting Steel - why not?
RE: Die Casting Steel - why not?
Regarding pressure in high pressure die casting, during the intensification stage it can exceed 69 MPa (10 ksi), which would definitely destroy ceramic molds like those used in investment casting. Die casting machines require locking forces ranging from 450 kN to ~ 35 MN (50-4000 tonf) in order to resist the high pressures developed.