alloy tubes, ASTM A213, ASTM A213 T9, heat exchanger tubes, superheater tubes

ASTM A213 T9 Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, Heat-Exchanger Tubes.
Grades containing the letter H in their designation have requirements different from those of similar grades not containing the letter H.
These different requirements provide higher creep-rupture strength than normally achievable in similar grades without these different requirements. ASTM A213 T9 tubes shall be made by the seamless process and shall be either hot finished or cold finished, as specified. Grade TP347HFG shall be cold finished. Heat treatment shall be done separately and in addition to heating for hot forming. The ferritic alloy and ferritic stainless steels shall be reheated. On the other hand, austenitic stainless steel tubes shall be furnished in the heat-treated condition. Alternatively, immediately after hot forming, while the temperature of the tubes is not less than the minimum solution