ABSTRACT The microstructure and mechanical properties of tungsten powder reduction furnace tube are investigated in this work. After service, the lamellar and skeleton-shape primary carbides of FeCr26Ni36Co15W5 alloy coarsened and formed a continuous network, much fine secondary carbide precipitated in the dendrite interior. The tensile strength and ductility of FeCr26Ni36Co15W5 alloy decreased. And, the creep strength of FeCr26Ni36Co15W5 alloy has reached the end of the service life. Meanwhile, the corrosion products were studied by XRD and XRF. It was found that the corrosion products were Na2WO4·2 h2O, Na2CO3·H2O and Cr4Ni15W,and the evaporation of catalyst (Na2CO3) results in a large amount of Na2CO3·H2O in the corrosion products. The hot corrosion mechanism of the reduction furnace tube is Type I hot corrosion.