Have to somewhat agree with Scott on this. There are several grades of Inconel 600, 617 625 690 X750 etc. and also Incoloy grades, which are even better in many cases. Any grade would probably work but some are better than others and of course that is all assuming that which ever material grade your talking about meets the chemical and heat treatment requirements for that grade. For example Inconel 600 has a tensile strength at 1600 degrees F of 15 ksi (which is about half the room temperature tensile of copper water tube you find at Home Cheapo). Where Inconel 718 has a 49 ksi tensile at 1600 F. Quite a bit stronger than 600. Also Inconel is not stainless steel, as mentioned in one post. Or steel at all for that matter. All Inconels and Incoloys are considered nickel based super alloys, although the Incoloy is mostly Fe (like steel).
1991 2+2 1993 convertible |