You'll need to be more specific before even starting. Fatigue varies widely for different alloy and heat treats. "Stainless steel" is not a sufficient description to get any meaningful information.
First get more specific composition information. Even then, I don't have a good answer for publicly available SN curves. My best recommendation is to either engage somebody with that information, or research in an engineering university library.
All I have is a mil spec. that does not provide tensile strenght for 316 Stainless Forging cold-worked. The material is under Mil-S-7702 Class C. If you have any reference material for Tensile strenght then I could put together a Goodman Diagram.
