Stainless Steel Casting

The first question you should be asking is what kind of stainless steel are you trying to cast.  Is it martensitic, ferritic, austenitic, duplex, precipitate hardening, or is it one of the stainless steel designated as a cast stainless steel (cast stainless steels are made to be cast but some of them are ussually the same as the wrought stainless steel except some may contain Si to help with the castability)?  Some stainless steels can be heat treated increase strength and some can’t.

Along with what type of stainless steel you want to cast you should be asking what is it going to be used for and what environment is it going to be placed in.  Different types of stainless are corrosion resistant to different environments.   Also the strengths of stainless steel are different at different temperatures.Also the microstructure of the stainless steel will be very important.  After casting austenitic stainless steels you WILL NOT have a pure austenitic microstructure there will also be ferrite present.  This will enhance the weldability, but will decrease the corrosion resistance.  There are heat treatments you can perform to change the microstructure.  How you cool the cast part will also effect microstructure.  Are you going to quench, air cool, or furnace cool?   If you quench what type of quench?  Water, oil, polymer etc?  What will the temperature of the quench be if you use one?  What will the temperature of the furnace be?  What will the atmosphere of the furnace be if furnace cool?  What type of atmosphere will be in the furnace?  Air? an inhert gas?Along the lines of microstructure.... chromium, silicon, molybdenum, and niobium promote the presence of ferrite in the microstructure.  Nickel, carbon, nitrogen, and manganese promote austenite.You can make you own stainless if you want to.  There are standards about what the composition of different grades of stainless steel are.  Once again it goes back to what properties do you want and what type of stainless steel you want to make.  At a bare minimum stainless steel has 11% Cr in it. Some good books to read to get some overview on the stainless steel are "Metals Handbook Desk Edition Second Edition" by ASM International, "ASM Handbook Volume 15: Casting" by ASM International, and for solidification theory I have found "Phase Transformations in Metals and Alloys" by D. A. Porter and K. E. Easterling very useful.  I have not read the "ASM Handbook Volume 15: Casting" yet, but it should have alot of the information on casting and solidification theory.