RT for weld A and B categories.
Shall testing be performed before or after heat treatment?
Test methods and evaluation norms at weld NDE shall be acc. to ASME BVD Code Section VIII., Div. 1, Ed. 2007, Add. 2009.
Material: SA-516 Gr. 70 HIC Spec. SA-516 M (carbon steel).
Operation fluid temperature 61 C°.
Content: toxic agent
Design pressure (inner): 0,5 MPa

Best to RT before heat treatment. If you were to do RT after treatment and found an indication or flaw, the work would have to be repaired, and then heat treated again.