Abstract: In the thermal power system, the electricity production efficiency may be improved by providing turbine members having the improved high temperature characteristic over the corresponding prior art turbine members. Turbine members may be provided by using high resistant steels composed of any one or ones selected from the group consisting of the components, including 0.08 to 0.13% of carbon (C), 8.5 to 9.8% of chromium (Cr), 0 to 1.5% of molybdenum (Mo), 0.10 to 0.25% of vanadium (V), 0.03 to 0.08% of niobium (Nb), 0.2 to 5.0% of tungsten (W), 1.5 to 6.0% of cobalt (Co), 0.002 to 0.015% of boron (B), 0.015 to 0.025% of nitrogen (N), and optionally, 0.01 to 3.0% of rhenium (Re), 0.1 to 0.50% of silicon (Si), 0.1 to 1.0% of manganese (Mo), 0.05 to 0.8% of nickel (Ni) and 0.1 to 1.3% of cupper.

Abstract: Nickel based superalloys with excellent mechanical strength, corrosion resistance and oxidation resistance, which consist essentially of chromium in an amount of 3 to 7% by weight, cobalt in an amount of 3 to 15% by weight, tungsten in an amount of 4.5 to 8% by weight, rhenium in an amount of 3.3 to 6% by weight, tantalum in an amount of 4 to 8% by weight, titanium in an amount of 0.8 to 2% by weight, aluminum in an amount of 4.5 to 6.5% by weight, ruthenium in an amount of 0.1 to 6%, hafnium in an amount of 0.01 to 0.2% by weight, molybdenum in an amount of less than 0.5% by weight, carbon in an amount 0.06% by weight or less, boron in an amount of 0.01% by weight or less, zirconium in an amount of 0.01% by weight or less, oxygen in an amount of 0.005% by weight or less, nitrogen in an amount of 0.005% by weight or less and inevitable impurities and the balance being nickel.

Abstract: An object of this invention is to provide a single-crystal nickel-based superalloy having high creep rupture strength at high temperatures and excel at corrosion resistance and oxidation resistance at high temperatures. Single-crystal nickel-based superalloys with high temperature strength, hot corrosion resistance and oxidation resistance comprising by weight, 3.0 to 7.0% Cr, 9.5 to 15.0% Co, 4.5 to 8.0% W, 3.3 to 6.0% Re, 4.0 to 8.0% Ta, 0.8 to 2.0% Ti, 4.5 to 6.5% Al, 0.01 to 0.2% Hf, less than 0.5% Mo, 0.01% or less C, 0.005% or less B, 0.01% or less Zr, 0.005% or less O, 0.005% or less N, and balance substantially Ni.

Abstract: Nickel based superalloys with excellent mechanical strength, corrosion resistance and oxidation resistance, which consist essentially of chromium in an amount of 3 to 7% by weight, cobalt in an amount of 3 to 15% by weight, tungsten in an amount of 4.5 to 8% by weight, rhenium in an amount of 3.3 to 6% by weight, tantalum in an amount of 4 to 8% by weight, titanium in an amount of 0.8 to 2% by weight, aluminum in an amount of 4.5 to 6.5% by weight, ruthenium in an amount of 0.1 to 6%, hafnium in an amount of 0.01 to 0.2% by weight, molybdenum in an amount of less than 0.5% by weight, carbon in an amount 0.06% by weight or less, boron in an amount of 0.01% by weight or less, zirconium in an amount of 0.01% by weight or less, oxygen in an amount of 0.005% by weight or less, nitrogen in an amount of 0.005% by weight or less and inevitable impurities and the balance being nickel.

Abstract: An object of this invention is to provide a single-crystal nickel-based superalloy having high creep rupture strength at high temperatures and excel at corrosion resistance and oxidation resistance at high temperatures. Single-crystal nickel-based superalloys with high temperature strength, hot corrosion resistance and oxidation resistance comprising by weight, 3.0 to 7.0% Cr, 9.5 to 15.0% Co, 4.5 to 8.0% W, 3.3 to 6.0% Re, 4.0 to 8.0% Ta, 0.8 to 2.0% Ti, 4.5 to 6.5% Al, 0.01 to 0.2% Hf, less than 0.5% Mo, 0.01% or less C, 0.005% or less B, 0.01% or less Zr, 0.005% or less O, 0.005% or less N, and balance substantially Ni.

Abstract: In the thermal power system, the electricity production efficiency may be improved by providing turbine members having the improved high temperature characteristic over the corresponding prior art turbine members. Turbine members may be provided by using high resistant steels composed of any one or ones selected from the group consisting of the components, including 0.08 to 0.13% of carbon (C), 8.5 to 9.8% of chromium (Cr), 0 to 1.5% of molybdenum (Mo), 0.10 to 0.25% of vanadium (V), 0.03 to 0.08% of niobium (Nb), 0.2 to 5.0% of tungsten (W), 1.5 to 6.0% of cobalt (Co), 0.002 to 0.015% of boron (B), 0.015 to 0.025% of nitrogen (N), and optionally, 0.01 to 3.0% of rhenium (Re), 0.1 to 0.50% of silicon (Si), 0.1 to 1.0% of manganese (Mo), 0.05 to 0.8% of nickel (Ni) and 0.1 to 1.3% of cupper.

Abstract: A method of designing a ferritic iron-base alloy having excellent characteristics according not to the conventional trial-and-error technique but to a theoretical method, and a ferritic heat-resistant steel for use as the material of turbines and boilers usable even in an ultrasupercritical pressure power plant.

Abstract: A method of designing a ferritic iron-base alloy having excellent characteristics according not to the conventional trial-and-error technique but to a theoretical method, and a ferritic heat-resistant steel for use as the material of turbines and boilers usable even in an ultrasupercritical pressure power plant. Specifically, the d-electron orbital energy level (Md) and the bond order (Bo) with respect to iron (Fe) of each alloying element of a body-centered cubic iron-base alloy are determined by the Dv-X.alpha. cluster method, and the type and quantity of each element to be added to the alloy are determined in such a manner that the average Bo value and average Md value represented respectively by the following equations:average Bo value=.SIGMA.Xi.(Bo)i 1average Md value=.SIGMA.Xi.