Hi John,

just to clarify. it is Cr that makes steel stainless not Ni. In order to make 300 series (316 for example) stainless you need Ni contents of 10 to 14%. 400 series stainless you need next to no if any Ni content at all but this comes at a price. 300 series steels are used in low temp applications and the food industry. 400 series is not well suited to these applications.