Graphite mould possible for stainless? 2

[Ibreakstuffdigitally]

Background: We have a stainless prototype part that is currently manufactured by a sand cast process. Production volumes will be relatively low, but better control of our finish and tolerances could potentially eliminate some machining steps, and even with some significant up front cost, we'd likely come out well ahead.

Our part is on the large side for investment casting (although we are investigating that as well)

My question is with regards to some references I've come across describing the use of graphite moulds in a semipermanent steel casting process (one is an '89 publication of an ASM guide to high performance castings, so I presume it to have some merit)

The difficulty I'm having is finding out more than the occasional "it's been done" type of reference.

The search hits that I come across are off shore which I hesitate to investigate.

Does anyone know if this is a viable process? Are there North American suppliers? Is the process aplicable to stainless alloys, or only to very specific irons and steels?

Any leads or information would be appreciated

 

[arunmrao]

Graphite mold is not possible due to carbon pickup. However, you may try a modified version of Shaw Process for your small quantity and high accuracy parts.

Unicast USA has a simple and good technology to meet your requirements. Hope it helps.

http://www.unicast.us/pubdocs/Ceramic Core Article.pdf

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

 

[EdStainless]

What method have you been using? What sand binder system?
Going to an isocyanate resin and using a ceramic wash on the molds you should be able to significantly improve casting quality.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[Ibreakstuffdigitally]

We've been told that the current process uses ester cured phenolic and a zircon wash, although we're shopping around for other suppliers who may supply better finishes (and who may used different processes) We'll definitely ask about the binder and the wash.