I am new to ductile iron stress analysis. can I use b31.3 code to analyse and the same load cases like sus, ope, exp and occ to check stresses. any specific thing to condsider for analysis.

Ductile Iron is a listed material in B31.3, so if the "service" falls within the jurisdiction of B31.3, then yes you can use this material.

Dear Mr.Richard,

Thank you very much for the reply.