ASTM A105/ A105M, identical with ASME SA-105/ SA-105M, is the standard specification for carbon steel forgings for piping applications. The application of ASME SA-105 forgings is endorsed by a series of ASME Boiler and Pressure Vessel Codes and ASME B31 Codes. However, the misuse of this material is commonly seen in some engineering practices. A typical misuse is that some fabricators may manufacture tubesheets from ASTM A105/ ASME SA-105 forgings by mistake.
In the standard specification, it states clearly in para 1.1 that “tubesheets and hollow cylindrical forgings for pressure vessel shells are not included within the scope of this specification”. Hence ASTM A105/ ASME SA-105 forgings CAN’T be used for the manufacture of tubesheets. The tubesheet is an important pressure vessel component for heat exchangers, heaters, superheaters and evaporators, etc. For a carbon steel tubesheet, if it is not allowed to be made from A105, what material should it be made from? The answer is ASTM A266 or ASME SA-266 forging as stated in para. 1.3.