If you are going to bid work to aerospace standards it would be a good idea for you to have a copy of the code on hand for yourself, even if you do your performance testing outside at another facillity.
D17 does cover a range of alloys in groupings very similar to 1595.
Special Metals Corporation own the name "Inconel" and "Incoloy" and I looked at their product handbook
http://www.specialmetals.com/documents/Product%20Handbook%20Part%201.pdf and could not find a direct reference to Inco 615 so I can't tell you which alloy group it falls under in D17
The Hobart institute is one place nearby who you can trust for good training and testing and there may be others.