Abstract: The present invention relates to the austenitic steel having improved resistance to oxidation at the high temperature, comprising not more than 0.10% C, 0.1-5.0% Si, not more than 3% Mn, 7-45% Ni, 15-30% Cr and sulfur content being restricted to not more than 0.003%. According to the present invention, by limiting the sulfur content in the austenitic steel to not more than 0.003%, preferably to not more than 0.0015%, the heat-resisting steel material which can show improved resistance to oxidation under severe conditions including repeated heating to high temperatures and cooling to room temperature is provided.

Abstract: A process for manufacturing high strength deep well casing, tubing, and drill pipes, which have improved resistance to stress corrosion cracking is disclosed. The process comprises the steps of preparing an alloy composition which is:______________________________________ C .ltoreq.0.05% Si .ltoreq.1.0% Mn .ltoreq.2.0% P .ltoreq.0.030% S .ltoreq.0.005% N 0-0.30% Ni 25-60% Cr 15-35% Mo 0-12% W 0-24% Cr (%) + 10Mo (%) + 5W (%) .gtoreq. 50% 1.5% .ltoreq. Mo (%) + 1/2W (%) .ltoreq. 12% Cu 0-2.0% Co 0-2.0% Rare Earths 0-0.10% Y 0-0.20% Mg 0-0.10% Ti 0-0.5% Ca 0-0.10% and incidental impurities balance; ______________________________________applying, after hot working, the solid solution treatment to the alloy at a temperature of from the lower limit temperature (.degree.C.) defined by the following empirical formula: 260 log C(%)+1300 to the upper limit temperature (.degree.C.

Abstract: An alloy useful for manufacturing high strength deep well casing, tubing and drill pipes for use in oil-well operations is disclosed. The alloy exhibits improved resistance to stress corrosion cracking in the H.sub.2 S--CO.sub.2 --Cl.sup.- environment, which comprises the following alloy composition:______________________________________ C: .ltoreq. 0.1% Si: .ltoreq. 1.0% Mn: .ltoreq. 2.0% P: .ltoreq. 0.030% S: .ltoreq. 0.005% N: 0-0.30% Ni: 25-60% Cr: 22.5-40% Mo: 0-3.5% (excl.) W: 0-7% (excl.) Cr (%) + 10Mo (%) + 5W (%) .gtoreq. 50%, 1.0% .ltoreq. Mo (%) + 1/2W (%) < 3.5% Cu: 0-2.0% Co: 0-2.0% Rare earths: 0-0.10% Y: 0-0.20% Mg: 0-0.10% Ca: 0-0.10% one or more of Nb, Ti, Ta, Zr and V in the total amount of 0.5-4.0, if necessary, Fe and incidental impurities: balance.

Abstract: An alloy useful for manufacturing high strength oil-well casing, tubing and drill pipes for use in oil-well operations is disclosed. The alloy exhibits improved resistance to stress corrosion cracking in the H.sub.2 S--CO.sub.2 --Cl.sup.- environment, which comprises the following alloy composition:______________________________________ C: .ltoreq. 0.1% Si: .ltoreq. 1.0% Mn: 3-20% P: .ltoreq. 0.030% S: .ltoreq. 0.005% N: 0-0.30% sol. Al .ltoreq. 0.5% Ni: 20-60% Cr: 15-35% Mo: 0-12% W: 0-24% Cr(%) + 10 Mo(%) + 5 W(%) .gtoreq. 50% 1/2 Mn(%) + Ni(%) .gtoreq. 25% 1.5% .ltoreq. Mo(%) + 1/2 W(%) .ltoreq. 12% Cu: 0-2.0% Co: 0-2.0% Rare Earths: 0-0.10% Y: 0-0.20% Mg: 0-0.10% Ti: 0-0.5% Ca: 0-0.10% Fe and incidental impurities: balance.

Abstract: An alloy useful for manufacturing high strength deep well casing, tubing and drill pipes for use in oil-well operations is disclosed. The alloy exhibits improved resistance to stress corrosion cracking in the H.sub.2 S--CO.sub.2 --Cl.sup.- -environment, which comprises the following alloy composition:______________________________________ C: .ltoreq.0.1% Si: .ltoreq.1.0% Mn: .ltoreq.2.0% P: .ltoreq.0.030% S: .ltoreq.0.005% N: 0-0.30% Ni: 25-60% Cr: 22.5-35% Mo: 0-7.5% (excl.) W: 0-15% (excl.) Cr (%) + 10Mo (%) + 5W (%) .gtoreq. 70% 3.5% .ltoreq. Mo (%) + 1/2W (%) < 7.5% Cu: 0-2.0% Co: 0-2.0% Rare earths: 0-0.10% Y: 0-0.20% Mg: 0-0.10% Ca: 0-0.10% ______________________________________one or more of Nb, Ti, Ta, Zr and V in the total amount of 0.5-4.0%, if necessary,Fe and incidental impurities: balance.

Abstract: An alloy useful for manufacturing high strength deep well casing, tubing and drill pipes for use in oil-well operations is disclosed. The alloy exhibits improved resistance to stress corrosion cracking in the H.sub.2 S-CO.sub.2 -Cl.sup.- environment, which comprises the following alloy composition:______________________________________ C: .ltoreq.0.1% Si: .ltoreq.1.0% Mn: .ltoreq.2.0% P: .ltoreq.0.030% S: .ltoreq.0.005% N: 0-0.30% Ni: 30-60% Cr: 15-35% Mo: 0-12% W: 0-24% Cr(%) + 10Mo(%) + 5W(%) .gtoreq. 110% 7.5% .ltoreq. Mo(%) + 1/2W(%) .ltoreq. 12% Cu: 0-2.0% Co: 0-2.0% rare earths: 0-0.10% Y: 0-0.20% Mg: 0-0.10% Ca: 0-0.10% one or more of Nb, Ti, Ta, Zr and V in the total amount of 0.5-4.0%, if necessary Fe and incidental impurities: balance.

Abstract: A 10-35% Cr ferritic stainless steel stabilized with 0.20-1.00% of Nb wherein Nb%.gtoreq.(8.times.C%+2.0%) with impurities, such as carbon, nitrogen, phosphorous, oxygen and sulfur reduced to given levels is disclosed. By reducing the sulfur content to a level of not greater than 0.002%, preferably less than 0.001% or in cases where copper and/or nickel is added, to a level of not greater than 0.005%, the corrosion resistance of the resulting steel can markedly be improved. Since the ferritic stainless steel of this invention also exhibits a combination of good surface appearance and formability, it can be substituted for certain austenitic stainless steels not only as a general corrosion resistant material, but also as a material for making external automotive trims and so on.

Abstract: A ferritic stainless steel having improved weldability and oxidation resistance, consisting essentially of 11.0 - 20.0% by weight of Cr, less than 0.10% by weight of C, less than 1.5% by weight of Si, less than 1.5% by weight of Mn, less than 1.5% by weight of Zr, the ratio of (Zr%)/(C% + N%) being higher than 7, and the balance of Fe, and the nitrogen amount being restricted to less than 0.015% by weight.