Metalshopteacher Posted January 17, 2009 Share Posted January 17, 2009 I am a Highschool metal shop teacher and I want to make some crucibles for melting aluminum in and I was told that stainless steel is the best for this because of its high melting point and it wont oxidize in the foundry... What I was wondering about, does anyone know if stainless forms a scale on the surface of the metal when heated, I don't recall it doing so but have never heated it up in my forge before. Quote Link to comment Share on other sites More sharing options...
dablacksmith Posted January 17, 2009 Share Posted January 17, 2009 it will scale but not as much as regular steel and it takes a lot of heat to get any ... when you forge it it will look just like steel but wont rust....should work fine for a crucible and at aluminum melting temps you wont have much problems with scaleing ...good luck! Quote Link to comment Share on other sites More sharing options...
bigfootnampa Posted January 17, 2009 Share Posted January 17, 2009 All stainless is not equal though... I have heard that some alloys will separate when heated leaving pockets of regular steel. The stuff I have worked doesn't have that problem though and forms a thin, tight, brownish/grey scale that I like the looks of. There are many alloys available and they have widely varied properties. There have been some other threads here about this and it would be wise to search these out and read them for more specifics. The stainless I have worked was softer than mild steel and forged more into the dark red heat zones. I can't tell you what alloys though as I have bought it as bolts with unknown content. Quote Link to comment Share on other sites More sharing options...
Frosty Posted January 18, 2009 Share Posted January 18, 2009 No problem at aluminum melt temps, virtually any SS will be just fine. Frosty Quote Link to comment Share on other sites More sharing options...
Quenchcrack Posted January 18, 2009 Share Posted January 18, 2009 I would make sure I used ferritic stainless steel, the type used for heat-resisting applications. Quote Link to comment Share on other sites More sharing options...
Trollhammer Posted January 18, 2009 Share Posted January 18, 2009 Might be cheaper to get a graphite or silicone carbide crucible. I've seen 'em under $50 for a crucible that will hold ten pounds of aluminum. For that matter, I've seen soup cans used(only a couple of goes before it burned up) and schedule 80 BLACK pipe(not galvanized) with a plate welded to the bottom. Check out melting metal in a home foundry, backyard metalcasting, metal casting. There's a heap of info about aluminum casting there, plus a bunch of other stuff. Mickey Quote Link to comment Share on other sites More sharing options...
Frosty Posted January 19, 2009 Share Posted January 19, 2009 It's only aluminum. Heck, using heat resistant SS would inhibit heat transfer to the al more than plain old SS will. It shouldn't be too expensive to have a couple small crucibles welded up at a muffler shop from their drops. I've used soup cans, black pipe and cast iron as well as "real" crucibles. Unless it's something metallurgically critical almost any non-reactive metal will do. Frosty Quote Link to comment Share on other sites More sharing options...
metalliferous Posted January 19, 2009 Share Posted January 19, 2009 If you're doing this to demonstrate the process or just as a hobby, mild steel will do fine. I'd figure SS would work too, but I can't see much of an advantage. Quote Link to comment Share on other sites More sharing options...
welder19 Posted January 19, 2009 Share Posted January 19, 2009 Here is where I buy my crucibles from, they are the best prices you can find.Budget Graphite Crucibles: Legend Inc. Sparks, Nevada USA welder19 Quote Link to comment Share on other sites More sharing options...
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