Abstract: A heat resistant Ni base alloy comprises, on a mass% basis, 0.1% or less C, 2% or less Si, 2% or less Mn, 0.005% or less S, 10 to 25% Cr, 2.1 to less than 4.5% Al, 0.08% or less N, 0.001 to 1% in total of one or more elements of B: 0.03% or less, Zr: 0.2% or less and Hf: 0.8% or less, and 2.5 to 15% in total of one or more elements of Mo: 0.01 to 15% and W: 0.01 to 9%. The alloy is suitable as a material for a pipe used in ethylene cracking furnace.

Abstract: A heat resistant high Cr ferritic steel comprising, in mass %, C : 0.02 to 0.15%, Mn: 0.05 to 1.5%, P : 0.03% or less, S : 0.015% or less, Cr: 8 to 13%, W : 1.5 to 4%, Co: 2 to 6%, V : 0.1 to 0.5%, Ta: 0.01 to 0.15%, Nb: 0.01 to 0.15%, Nd: 0.001 to 0.2%, N : 0.02% or less, B : 0.0005 to 0.02%, Al: 0.001 to 0.05%, Mo: 0 to 1%, Si: 0 to 1%, Ca: 0 to 0.02%, La: 0 to 0.2%, Ce: 0 to 0.2%, Y : 0 to 0.2%, Hf: 0 to 0.2%, the contents of Nd and N satisfying the formula: Nd(%) ≦5×N(%)+0.1(%), and the balance being Fe and incidental impurities. The steel is excellent in high temperature long term creep strength and toughness and can be used under the ultra super critical steam condition such as a temperature of 625° C. and a pressure of 300 atm.

Abstract: A high-temperature austenitic stainless steel having improved weldability is disclosed. The steel consists essentially, by weight, of:C: 0.05%-0.15%, Si: less than 1.0%, Mn: 2.0% or less,P: 0.04% or less, S: 0.01% or less, Cr: 20%-30%,Ni: 10%-15%, N: 0.10%-0.30%,B: 0.0010%-0.01%,one or two of La and Ce: 0.01%-0.10% in total,Al: 0.01%-0.20%, anda balance of Fe and incidental impurities, wherein the contents of N and Al satisfy the following inequality:% N+2.times.% Al.ltoreq.0.500%and the value for Ni balance (Ni bal.) of the steel calculated by the following formula is in the range of from -1.0% to +3.0%:Ni bal. (%)=% Ni+0.5.times.% Mn+30.times.(% C+% N)-1.1.times.(% Cr+1.5.times.% Si)+8.2.

Abstract: A heat resistant austenitic stainless steel having high strength at elevated temperatures. The steel consists of 0.05 to 0.15% carbon, not more than 0.5% silicon, 0.05 to 0.50% manganese, 17 to 25% chromium, 7 to 20% nickel, 2.0 to 4.5% copper, 0.10 to 0.80% niobium, 0.001 to 0.010% boron, 0.05 to 0.25% nitrogen, 0.003 to 0.030% sol.aluminum, 0 to 0.015% magnesium and the balance being iron and incidental impurities. The steel may contain 0.3 to 2.0% molybdenum and/or 0.5-4.0% tungsten. The steel exhibits high creep rupture strength at elevated temperatures for long periods of time, and can be produced at low cost. The steel is suitable for use in the structural members for boilers, chemical plants and other installations operated in a high temperature environment.

Abstract: A high Cr austenitic heat resistant alloy excellent in high temperature strength which essentially consists of, in weight percent, from more than 0.02% to 0.10% C, not more than 1.0% Si, not more than 2.0% Mn, 28 to 38% Cr, 35 to 60% Ni, from more than 0.5% to 1.5% Ti, not more than 0.05% N, 0.01 to 0.3% Al, 0.001 to 0.01% B, 0 to 0.1% Zr, 0 to 1.0% Nb, one or both of 0.5 to 3.0% Mo and 1.0 to 6.0% W, and the balance being Fe and incidental impurities. The alloy may further contain one or both of 0.001 to 0.05% Mg and 0.001 to 0.05% Ca. This alloy is suitable for producing a single layered tube which is less expensive and more reliable than the conventional double layered tube.

Abstract: A low-Cr ferritic steel with improved toughness as well as creep strength is disclosed, which consists essentially of, by weight %:C: 0.03-0.12%, Si: 0.70% or less, Mn: 0.10-1.50%,Ni: 2.0% or less, Cr: 1.50-3.50%, W: 1.0-3.0%,V: 0.10-0.35%, Nb: 0.01-0.10%,B: 0.00010-0.020%, N: 0.005% or less,Al: 0.005% or less,Ti: not less than 0.001% but less than 0.05%,Cu: 0.10-2.50%,at least one of La, Ce, Y, Ca, Zr, Ta each in an amount of 0-0.20%, and Mg in an amount of 0-0.05%,Mo in an amount of 0-0.40%, anda balance of Fe and incidental impurities including P: not more than 0.030% and S: not more than 0.015%.

Abstract: A Cu-containing, high-Cr ferritic, heat-resistant steel is prevented from copper checking without a reduction in strength, toughness, resistance to hot corrosion, or oxidation, and its weldability is maintained at satisfactory levels. The steel consists essentially, on a weight basis, of: C: 0.03-0.15%, Si: at most 0.7%, Mn: 0.1-1.5%, Ni: 0.05-1.0%, Cr: 8-14%, W: 0.8-3.5%, V: 0.1-0.3%, Nb: 0.01-0.2%, N: 0.001-0.1%, Al: at most 0.05%, Cu: 0.4-3.5%, B: 0-0.02%, one or more elements selected from the group consisting of La, Ce, Ca, Y, Ti, Zr, and Ta: 0-0.2% each, and a balance of Fe and incidental impurities, wherein the Cu and Ni contents satisfy the following Inequality: 2.5.ltoreq.(%Cu)/(%Ni).ltoreq.4.5.

Abstract: A low-alloy steel consists essentially, on a weight basis, of: C: 0.03-0.12%, Si: at most 0.7%, Mn: 0.1-1.5%, Ni: at most 0.8%, P: at most 0.03%, S: at most 0.015%, Cr: 1.5-3.5%, W: 1-3%, V: 0.1-0.35%, Nb: 0.01-0.1%, B: 0.0001-0.02%, N: less than 0.005%, Al: less than 0.005%, Ti: 0.001-0.1%, optionally one or more elements selected from the group consisting of: La, Ce, Y, Ca, Zr, and Ta: 0.01-0.2%, Mg: 0.0005-0.05%, and Mo: 0.01-0.4%, and a balance of Fe and incidental impurities, wherein the Ti and Ni contents satisfy the following inequality:0.080.gtoreq.Ti(%)-(48/14).times.N(%).gtoreq.0.003.The steel has improved creep strength at high temperatures and improved toughness. It can be substituted for expensive austenitic stainless steels or high-Cr ferritic steels.

Abstract: High-vanadium austenitic alloys, which are structurally stable and have improved corrosion resistance in wet corrosive environments and high-temperature corrosion resistance in reducing atmosphere, contain Ni by 33.0 to 60.0 weight %, Cr by 23.0 to 28.0 weight %, V by 2.4 to 5.0 weight %, C by 0.10 weight % or less, N by 0.05 weight % or less, Si by 0.35% weight % or less, Al by 0.5 weight % or less, Mn by 1.5% weight % or less, P by 0.020 weight % or less, S by 0.005 weight % or less, and one or more selected from the group consisting of B by 0.0010 to 0.010 weight %, Zr by 0.010 to 0.06 weight %, Ti by 0.03 to 0.50% weight %, and Nb by 0.05 to 1.0 weight %, the balance being Fe and impurities.

Abstract: A high-strength high-Cr steel with excellent high-temperature strength and toughness as well as improved resistance to oxidation and high-temperature corrosion is disclosed, which consists essentially of, in weight %:C : 0.04-0.2%, Si: not greater than 0.7%, Mn: 0.1-1.5%, Ni: not greater than 1%, Cr: 8-14%, Mo: 0.01-1.2%, W: 0.8-3.5%, V : 0.1-0.3%, Nb: 0.01-0.2%, Al: not greater than 0.05%, Cu: 0.4-3%, Mg: 0.0005-0.5%, N: 0.001-0.1%, B : 0-0.02%,at least one of La, Ce, Y, Ca, Ti, Zr, and Ta each in an amount of 0-0.2%, andFe and incidental impurities: balance.

Abstract: A high-strength, heat-resistant steel with improved formability is disclosed, which consists essentially of, by weight %:______________________________________ C: 0.05-0.30%, Si: not greater than 3.0%, Mn: not greater than 10%, Cr: 15-35%, Ni: 15-50%, Mg: 0.001-0.02%, B: 0-0.01%, Zr: 0-0.10%, Ti: 0-1.0%, Nb: 0-2.0%, Al: 0-1.0%, and Mo: 0-3.0%, W: 0-6.0%, (Mo + 1/2 W = 3.0% or less) ______________________________________a balance of Fe and incidental impurities, of the impurities, oxygen and nitrogen being restricted to 50 ppm or less and 200 ppm or less, respectively, and the austenite grain size number being restricted to No. 4 or coarser.

Abstract: A low Si high-temperature strength steel tube with improved ductility and toughness which consists essentially of: not more than 0.10 wt % of carbon (C), not more than 0.15 wt % of silicon (Si), not more than 5 wt % of maganese (Mn), 20 to 30 wt % of cromium (Cr), 15 to 30 wt % of nickel (Ni), 0.15 to 0.35 wt % of nitrogen (N), 0.10 to 1.0 wt % of niobium (Nb) and not more than 0.005 wt % of oxygen (O.sub.2); and at least one of 0.020 to 0.1 wt % of aluminum (Al) and 0.003 to 0.02 wt % of magnesium (Mg) in an amount defined by the following formula:0.006 (%).ltoreq.1/5Al(%)+Mg(%).ltoreq.0.020 %the balance being Fe and inevitable impurities.

Abstract: An austenitic steel having improved high-temperature strength as well as corrosion resistance is disclosed. The steel consists essentially of, by weight %:C: not more than 0.15%, Si: not more than 1.0%,Mn: not more than 10%, Cr: 20-30%,Ni: 30-55%,at least one of Mg and Ca in a total amount of 0.0010-0.0500%,Mo: 0.5-6.0% and/or W: 1.0-12.0%, whereinMo(%)+1/2W(%)=0.5-6.0(%),B: 0-0.0100%, Zr: 0-0.200%,Ti: 0-0.30%, Nb: 0-1.00%,V: 0-1.00%, andbalance: Fe and incidental impurities, of which impurities P, S, and Al are restricted to:P: not more than 0.020%,S: not more than 0.010%, andAl: not more than 0.030%,P (%)+S (%)+Al (%) being less than 0.050%.