You can't use B16.5 for comparison of similar material to obtain a pressure-temperature classification for this material. The reason is that ASTM A 694 is not endorsed by ASME B16.5.
What is your application (ASME B31.8 Gas Transmission and Distribution Piping Code)? If so, you need to review Chapter 1 and Chapter 4 for application of this material. It is endorsed in Appendix C of this Piping Code.
Unfortunately, I see no other option other than to use a flange material that is endorsed by ASME B16.5 for this application. ASTM A 694 is not on the list of materials for use in flanges under B16.5, and I would not recommend trying to compare this material with any of the endorsed materials in B16.5.