Dear All,
I need to perform the flange leakage analysis by Caesar; I need to select flange group by ASME B16.5 in order to define the working pressure.
I have A694 Gr. F65 flanges and I can't find this material flange under Table 1A of ASME B16.5 and consequently, I can't define a material group flange.
Is there any material similar to A694 Gr.F65? Can Someone help me please?... Thank you to all

For properties you may compare with API 5L X65 as detailed by B31.3.
Formally, you cannot substitute it in B16.5, even it's a "grade 65".

But If I need to select the material group for this material (A694 Gr. F65) as per B16.5 , how can I do this? In Which group my material is?

IMO, the answer is simple: you cannot do it inside B16.5.
Flanges manufactured of materials other than those listed in B16.5/Table 1A cannot be marked as being in conformance with ASME B16.5.
This statement is subject of formal Interpretation 4-14.

Out of B16.5, as your personal exercise in a calculation, look at a group that has "grade 65", study that material an compare with yours. Also, you should pay attention to the temperature limitations of F65.

Ok, thank you for your reply;
But, If I have to verify this flange with pressure equivalent method, i need to select the working pressure that dipends of material/rating/temperature of my flange; If I don't use B16.5, maybe I can use MSS -SP-44- that covers A694 Gr.65 up to rating 900 and use table 3 for select my working pressure, Are you agree?

IMO you can consider PEQ method with the values of Table 3/MSS -SP-44 as the "total" pressure and, by similarity with 31.3 requirements for X65, you would limit the temperature to 400F (204C). In case your applicable Code is more restrictive for temperature, you should consider it.

In case you find that the rating values given for B16.5 group 1.3 are more restrictive than those of MSS -SP-44, you can proceed by considering B16.5 values, however it is difficult to argue why you deal with B16.5 with a non-B16.5 material (even it is a grade 65 material, similar with one of group 1.3).