| abstract |
Si: 1%, Mn: 2%, P: 0.03%, S: 0.01%, Ni: 35 to 60%, Cr: 18 to 38%, W: 3 to 11% 0.01 to 0.5% of Nb, 0.01 to 0.05% of Nb and 0.01 to 0.5% of Zr: 0.01 to 1.2% of Ti, 0.0001 to 0.01% of B, 0 to 0.02% 0.5%, and at least one selected from Mo? 1%, Cu? 1%, Co? 1%, Ca? 0.05%, Mg? 0.05% and REM? 0.1% (D 탆) of not more than 1000 탆 at the center of the thickness of the tube and satisfies the formula [d? 1500 - 2.5 占 5 占〕] A seamless austenitic heat-resistant alloy tube which is used by direct fillet welding of the outer surface of the tube having the thickness of the oxide layer on the outer surface of the outer surface of 15 mu m or less is excellent in content folding resistance and suppresses cracking in HAZ during welding It can be suitably used as a member of a high-temperature apparatus such as a furnace wall pipe of a power generation boiler. |