Casting steel jewelry

[shahgems]

Does anyone have experience with casting stainless steel jewelry? I have many people asking for steel jewelry but I have no idea how complicated steel casting is. We do gold, silver and brass casting (lost wax investment casting) regularly but never stainless steel.
I understand we would need different equipment. Any help or articles would be appreciated!

Regards,
Rishabh

[Jolson]

Steel, especially stainless is very tricky to cast, not to say it’s impossible - it’s how plenty of parts for engines or turbines are made; and everyone knows the good old cast iron pan. But without proper equipment (which can take up an entire room it’s very difficult to end up with parts that don’t have that signature cast iron pan texture and porosity that comes from the huge grain structure iron and steel alloys end up with from cooling in the mold so quickly, or in some cases your material is so hot when you pour that it can permeate your investment leaving a rough skin and even glass fused to your casting. You can only avoid permeation problems with ceramic shell casting, which is like investment casting with extra steps to create a ceramic shell on your wax before pouring investment - there are good guides on youtube. Simply trying to cast colder will just result in cold shuts and improper mold fill, steel is more viscous than gold so it flows slower (think honey vs water but not as extreme) this is caused by nickel and chromium the two elements responsible for your stainless properties. It also helps to choose an austenitic steel, something like 304 or 316 stainless, it will have an easier time flowing into your mold and keep a finer grain structure. Martensitic or Ferritic alloys will be harder to cast and more prone to issues like shrinkage and hot tearing (not that austenitic steels aren’t also prone to these issues just to a lesser degree) but will afford you the ability to harden your castings like you would a knife or spring. Now the hardest factor to control, unless you already have some very nice casting equipment, is your atmosphere. Gold and the things we alloy it with are usually pretty good about absorbing gasses, of course we see oxidation but that is a given with such a highly reactive element as oxygen, steel however will absorb nitrogen and hydrogen readily as you melt and cast it and make nastier byproducts from oxidation. Unless you cast in an argon environment, your steel will want to absorb the air around it and drag it in as porosity in your final piece.