Abstract: Provided is martensitic heat-resistant steel for boiler applications with a unique combination of enhanced creep strength and excellent oxidation resistance upon high temperature exposure in steam containing environments contacts (in wt.-%): C: 0.10 to 0.16%, Si: 0.20 to 0.60%, Mn: 0.30 to 0.80%, P?0.020%, S?0.010%, Al?0.020%, Cr: 10.5 to 12.00%, Mo: 0.10 to 0.60%, V: 0.15 to 0.30%, Ni: 0.10 to 0.40%, B: 0.008 to 0.015%, N:0.002 to 0.020%, Co: 1.50 to 3.00%, W: 1.50 to 2.50%, Nb: 0.02 to 0.07%, Ti: 0.001-0.020%, iron and unavoidable impurities. The steel is normalized for about 10 to about 120 minutes at a temperature of 1050-1170° C. and cooled down in air or water to room temperature, and then tempered for at least one hour at a temperature of 750-820° C. The steel has a martensitic microstructure with average ?-ferrite content of less than 5 vol.-%.

Abstract: Disclosed is a metallurgical vessel, in particular a converter for treating liquid molten metals, in particular steel, formed of a refractory lining and a supporting metal shell that surrounds the refractory lining. The vessel is composed of welded together shell rings and dished parts of creep-resistant steel with plate thicknesses of up to 100 mm. The creep-resistant steel used is a highly resistant, water-quenched and then tempered close-grained structural steel with the following composition in wt.-% C 0.14-0.22 Cr 0.4-1.0 Mo 0.3-0.8 Ni 1.5-3.0 V 0.05-0.12 Mn 0.7-1.3 Pmax 0.015 Smax 0.003 Al 0.015-0.065 Si 0.20-0.60 Cumax 0.15 Nmax 0.012 Camax 0.004 the remainder being iron and impurities due to the production process.

Abstract: A high-temperature steel for boiler making having improved creep strength and low tendency to hardening in welded condition, having the following melt analysis (wt. %):C 0.050 to 0.100%Si 0.15 to 0.45%Mn 0.30 to 0.70%P .ltoreq.0.020%S .ltoreq.0.010%Al .ltoreq.0.020%Cr 2.20 to 2.60%Mo 0.90 to 1.10%V 0.20 to 0.30%Ti 0.05 to 0.10%B 0.0015 to 0.0070%N .ltoreq.0.01%The balance of the steel is comprised of iron and ordinary impurities. The steel is annealed for a period of about 30 to about 60 minutes at about 980.degree. C. to about 1040.degree. C., thereupon cooled in air, and then tempered for at least one hour at about 730.degree. C. to about 760.degree. C.