High-temperature strength, weldability, and decarburization behavior in liquid sodium of 2¼ Cr— 1 Mo steel with a wide variety of heat treatments and some carbon stabilized 2¼ Cr—1 Mo steels are examined for the purpose of material selection of liquid-metal fast breeder reactor (LMFBR) steam generator tubes. Decarburization of 2¼ Cr—Mo steel in sodium can be suppressed when it is appropriately normalized and tempered instead of annealed. The 2¼ Cr—1 Mo—Nb—Ni steel is considered to be preferable to other stabilized steels, since a small addition of nickel assures sufficient strength, even if the normalizing temperature is as low as 950°C. Stabilized steels should be welded carefully to obtain a fully penetrated bead. Preheating above 200°C and postheating above 720°C are required for stabilization. Compared with all the investigated properties, the materials recommended for LMFBR steam generator tubes are normalized-tempered 2¼ Cr— 1 Mo steel and, if decarburization is not allowable, 2¼ Cr—1Mo—Nb—Ni steel, with the condition that a sound-welded joint can be available.