Hello guys,

I am facing an error when using material A672 C60 with ASME code B31.1 the allowable stresses is 0 while switch code to B31.3 allowable stress appear.
Actually I am working now in power station project so I have to use B31.1.

IS ther anyone have solution for this problem?

It looks to me that you have all the necessary material data EXCEPT for the B31.1 basic allowable stresses.
You can either type in SC & SH1 (and SH2, SH3, etc., if needed) for this model. Or, you can add these basic allowable stresses to the material database so that you can use it again and again.
First step, collect your basic allowable stresses.

Thank you David but do you mean with other data ? I already have elastic modulus, passion ratio and expansion coefficient . Is there another data should I have except the allowable stresses?

A672 is not in the CAESAR II material database for B31.1. Therefore the software is giving you the entry for "All Codes". This is just basic mechanical properties - no allowable stresses.

As Dave says above, you can use the Material Database Editor to add an entry for this material and B31.1 combination.