Alloy and composite steel tube with corrosion resistance in combustion environment where vanadium sodium sulphur, and chlorine are present.

摘要

An alloy exhibiting corrosion resistance in a combustion environment where V, Na, S and Cl are present comprises, in weight percent, not more than 0.05% C, 0.02 - 0.5% Si, 0.02 - 0.5% Mn, 15 - 35% Cr, 0.5 - 4% Mo, 10 - 40% Co, 5 - 15% Fe, 0.5 - 5% W, 0.0003 - 0.005% Ca and the remainder of Ni at a content of not less than 4% and unavoidable impurities, provided that Cr (%) + 0.5Ni (%) + 3Mo (%) >/= 30 (%) and Ni (%) + 0.5Co (%) > Cr (%) + Mo (%) + W (%). A composite steel tube exhibiting corrosion resistance in a combustion environment where V, Na, S and Cl are present comprises an inner tube constituted of Cr-containing boiler tube and an outer tube constituted of the alloy.