Abstract: The production method for producing a rifled tube, which includes a plurality of first helical ribs on its inner surface, includes: a steps of: preparing a steel tube; and producing a rifled tube by performing cold drawing on a steel tube by using a plug which includes a plurality of second helical ribs, the plug satisfying Formulae and: 0.08 <W×(A?B)×N/(2?×A)<0.26??(1) 0.83<S×(A?B)×N/(2×M)<2.0??(2) where, W is a width of a groove bottom surface of the helical groove; A is a maximum diameter of the plug; B is a minimum diameter of the plug; N is a number of the second helical ribs; S is the width of the groove bottom surface; and M is a pitch of adjacent second helical ribs.

Abstract: A high Cr austenitic stainless steel with a chemical composition consisting of in terms of % by mass, 0.03 to 0.12% of C, 0.10 to 1.00% of Si, 0.10 to 3.00% of Mn, 0.030% or less of P, 0.020% or less of S, 21.50 to 28.00% of Cr, more than 26.00 and not more than 35.00% of Ni, more than 2.00 and not more than 5.00% of W, 0.80% or less of Co, 0.01 to 0.70% of V, 0.15 to 1.00% of Nb, 0.001 to 0.040% of Al, 0.0001 to 0.0100% of B, 0.010 to 0.400% of N, 0.001 to 0.200% of Zr, 0.001 to 0.200% of Nd, 0.001 to 0.200% of Ta, 0.020 to 0.200% of Ta+0.8Nd+0.5Zr, 0.025% or less of Ti+Sn+Sb+Pb+As+Bi, 0.0090% or less of O, and a remainder consisting of Fe and impurities.

Abstract: An austenitic heat-resistant alloy has a chemical composition of, in mass %: 0.04 to 0.14% C; 0.05 to 1% Si; 0.5 to 2.5% Mn; up to 0.03% P; less than 0.001% S; 23 to 32% Ni; 20 to 25% Cr 1 to 5% W; 0.1 to 0.6% Nb; 0.1 to 0.6% V; 0.1 to 0.3% N; 0.0005 to 0.01% B; 0.001 to 0.02% Sn; up to 0.03% AI; up to 0.02% 0; 0 to 0.5% Ti; 0 to 2% Co; 0 to 4% Cu; 0 to 4% Mo; 0 to 0.02% Ca; 0 to 0.02% Mg; 0 to 0.2% REM; and the balance being Fe and impurities. The alloy microstructure has a grain size number in accordance with ASTM E112 of 2.0 or more and less than 7.0.

Abstract: An austenitic heat-resistant alloy is provided that provides good crack resistance and high-temperature strength in a stable manner. The austenitic heat-resistant alloy has a chemical composition of, in mass %: 0.04 to 0.15% C; 0.05 to 1% Si; 0.3 to 2.5% Mn; up to 0.04% P; up to 0.0015% S; 2 to 4% Cu: 11 to 16% Ni; 16 to 20% Cr; 2 to 5 % W; 0.1 to 0.8% Nb; 0.05 to 0.35% Ti; 0.001 to 0.015% N; 0.0005 to 0.01% B; up to 0.03% Al; up to 0.02 % O; 0 to 0.02 % Sn; 0 to 0.5 % V; 0 to 2 % Co; 0 to 5% Mo; 0 to 0.02% Ca; 0 to 0.02% Mg; 0 to 0.2% REM; and the balance being Fe and impurities, the alloy having a microstructure with a grain size represented by a grain size number in accordance with ASTM E112 of 2.0 or more and less than 7.0.

Abstract: A high Cr austenitic stainless steel with a chemical composition consisting of in terms of % by mass, 0.03 to 0.12% of C, 0.10 to 1.00% of Si, 0.10 to 3.00% of Mn, 0.030% or less of P, 0.020% or less of S, 21.50 to 28.00% of Cr, more than 26.00 and not more than 35.00% of Ni, more than 2.00 and not more than 5.00% of W, 0.80% or less of Co, 0.01 to 0.70% of V, 0.15 to 1.00% of Nb, 0.001 to 0.040% of Al, 0.0001 to 0.0100% of B, 0.010 to 0.400% of N, 0.001 to 0.200% of Zr, 0.001 to 0.200% of Nd, 0.001 to 0.200% of Ta, 0.020 to 0.200% of Ta+0.8Nd+0.5Zr, 0.025% or less of Ti+Sn+Sb+Pb+As+Bi, 0.0090% or less of O, and a remainder consisting of Fe and impurities.

Abstract: The production method for producing a rifled tube, which includes a plurality of first helical ribs on its inner surface, includes: a steps of: preparing a steel tube; and producing a rifled tube by performing cold drawing on a steel tube by using a plug which includes a plurality of second helical ribs, the plug satisfying Formulae and: 0.08 <W×(A?B)×N/(2?×A)<0.26??(1) 0.83<S×(A?B)×N/(2×M)<2.0??(2) where, W is a width of a groove bottom surface of the helical groove; A is a maximum diameter of the plug; B is a minimum diameter of the plug; N is a number of the second helical ribs; S is the width of the groove bottom surface; and M is a pitch of adjacent second helical ribs.

Abstract: An austenitic stainless steel with a chemical composition including in terms of mass %: 0.05 to 0.13% of C, 0.10 to 1.00% of Si, 0.10 to 3.00% of Mn, 0.040% or less of P, 0.020% or less of S, 17.00 to 19.00% of Cr, 12.00 to 15.00% of Ni, 2.00 to 4.00% of Cu, 0.01 to 2.00% of Mo, 2.00 to 5.00% of W, 2.50 to 5.00% of 2Mo+W, 0.01 to 0.40% of V, 0.05 to 0.50% of Ti, 0.15 to 0.70% of Nb, 0.001 to 0.040% of Al, 0.0010 to 0.0100% of B, 0.0010 to 0.0100% of N, 0.001 to 0.20% of Nd, 0.002% or less of Zr, 0.001% or less of Bi, 0.010% or less of Sn, 0.010% or less of Sb, 0.001% or less of Pb, 0.001% or less of As, 0.020% or less of Zr+Bi+Sn+Sb+Pb+As, 0.0090% or less of O, and a remainder including Fe and impurities.

Abstract: A Ni-based heat resistant alloy as pipe, plate, rod, forgings and the like consists of C?0.15%, Si?2%, Mn?3%, P?0.03%, S?0.01%, Cr: 15% or more and less than 28%, Mo: 3 to 15%, Co: more than 5% and not more than 25%, Al: 0.2 to 2%, Ti: 0.2% to 3%, Nd: fn to 0.08%, and O?0.4Nd, further containing, as necessary, at least one kind of Nb, W, B, Zr, Hf, Mg, Ca, Y, La, Ce, Ta, Re and Fe of specific amounts, the balance being Ni and impurities, wherein, fn=1.7×10?5d+0.05{(Al/26.98)+(Ti/47.88)+(Nb/92.91)}. In the formula, d denotes an average grain size (?m), and each element symbol denotes the content (mass %) of that element. If the alloy contains W, Mo+(W/2)?15% holds. The alloy has improved ductility after long-term use at high temperatures, and cracking due to welding can be avoided.

Abstract: After an inner wall tube, made of steel or alloy containing not less than 2% of Cr, whose outer surface thereof is machined and/or ground to a thickness of 0.1 mm or more including the scale layer, is inserted into an outer wall tube, made of ferritic steel containing not less than 2% of Cr, in which an oxide scale layer containing Cr and having a thickness of 10 to 30 ?m is formed in the inner surface thereof, cold working at an outside diameter reduction rate of 5 to 30% is performed. Similarly cold worked after an inner wall tube having an oxide scale layer on the outer surface thereof, is inserted into an outer wall tube whose inner surface is machined and ground. A double-walled tube made has a uniform gap and an excellent thermal conductivity, and is suitable as materials for SG tubes of future FBR.

Abstract: A Ni-based heat resistant alloy as pipe, plate, rod, forgings and the like consists of C?0.15%, Si?2%, Mn?3%, P?0.03%, S?0.01%, Cr: 15% or more and less than 28%, Mo: 3 to 15%, Co: more than 5% and not more than 25%, Al: 0.2 to 2%, Ti: 0.2% to 3%, Nd: fn to 0.08%, and O?0.4Nd, further containing, as necessary, at least one kind of Nb, W, B, Zr, Hf, Mg, Ca, Y, La, Ce, Ta, Re and Fe of specific amounts, the balance being Ni and impurities, wherein, fn=1.7×10?5d+0.05{(Al/26.98)+(Ti/47.88)+(Nb/92.91)}. In the formula, d denotes an average grain size (?m), and each element symbol denotes the content (mass %) of that element. If the alloy contains W, Mo+(W/2)?15% holds. The alloy has improved ductility after long-term use at high temperatures, and cracking due to welding can be avoided.

Abstract: An austenitic heat resistant alloy includes, by mass percent, C: 0.15% or less, Si: 2% or less, Mn: 3% or less, Ni: 40 to 60%, Co: 10.14 to 25%, Cr: 15% or more and less than 28%, either one or both of Mo: 12% or less and W: less than 0.05%, the total content thereof being 0.1 to 12%, Nd: 0.001 to 0.1%, B: 0.0005 to 0.006%, N: 0.03% or less, O: 0.03% or less, at least one selected from Al: 1.36% or less, Ti: 3% or less, and Nb: 3% or less, and the balance being Fe and impurities. The contents of P and S in the impurities are P: 0.03% or less and S: 0.01% or less. The alloy satisfies 1?4×Al+2×Ti+Nb?12 and P+0.2×Cr×B?0.035, where an element in the Formulas represents the content by mass percent.

Abstract: [Problem to be Solved] A Ni-based alloy product consisting of, by mass percent, C: 0.03 to 0.10%, Si: 0.05 to 1.0%, Mn: 0.1 to 1.5%, Sol.Al: 0.0005 to 0.04%, Fe: 20 to 30%, Cr: not less than 21.0% and less than 25.0%, W: exceeding 6.0% and not more than 9.0%, Ti: 0.05 to 0.2%, Nb: 0.05 to 0.35%, and B: 0.0005 to 0.006%, the balance being Ni and impurities, the impurities being P: 0.03% or less, S: 0.01% or less, N: less than 0.010%, Mo: less than 0.5%, and Co: 0.8% or less, wherein a value of effective B (Beff) defined by the formula, Beff (%)=B?(11/14)×N+(11/48)×Ti, is 0.0050 to 0.0300%, and the rupture elongation in a tensile test at 700° C. and at a strain rate of 10?6/sec is 20% or more. This alloy may contain one or more kinds of Cu, Ta, Zr, Mg, Ca, REM, and Pd.

Abstract: To provide an austenitic stainless steel which has an excellent high-temperature corrosion thermal fatigue cracking resistance. An austenitic stainless steel containing, by mass %, Cr: 15.0 to 23.0%, and Ni: 6.0 to 20.0%, wherein a near-surface portion is covered with a worked layer with high energy density having an average thickness of 5 to 30 ?m.

Abstract: After an inner wall tube, made of steel or alloy containing not less than 2% of Cr, whose outer surface thereof is machined and/or ground to a thickness of 0.1 mm or more including the scale layer, is inserted into an outer wall tube, made of ferritic steel containing not less than 2% of Cr, in which an oxide scale layer containing Cr and having a thickness of 10 to 30 ?m is formed in the inner surface thereof , cold working at an outside diameter reduction rate of 5 to 30% is performed. Similarly cold worked after an inner wall tube having an oxide scale layer on the outer surface thereof, is inserted into an outer wall tube whose inner surface is machined and ground. A double-walled tube made has a uniform gap and an excellent thermal conductivity, and is suitable as materials for SG tubes of future FBR.

Abstract: An austenitic heat resistant alloy, which contains, by mass percent, C?0.15%, Si?2%, Mn?3%, Ni: 40 to 80%, Cr: 15 to 40%, W and Mo: 1 to 15% in total content, Ti?3%, Al?3%, N?0.03%, O?0.03%, with the balance being Fe and impurities, and among the impurities P?0.04%, S?0.03%, Sn?0.1%, As?0.01%, Zn?0.01%, Pb?0.01% and Sb?0.01%, and satisfies the conditions [P1=S+{(P+Sn)/2}+{(As+Zn+Pb+Sb)/5}?0.050], [0.2?P2=Ti+2Al?7.5?10×P1], [P2?9.0?100×O] and [N?0.002×P2+0.019] can prevent both the liquation crack in the HAZ and the brittle crack in the HAZ and also can prevent defects due to welding fabricability, which occur during welding fabrication, and moreover has excellent creep strength at high temperatures. Therefore, the alloy can be used suitably as a material for constructing high temperature machines and equipment, such as power generating boilers, plants for the chemical industry and so on.

Abstract: An austenitic heat resistant alloy consisting of, by mass percent, C: 0.15% or less, Si: 2% or less, Mn: 3% or less, Ni: 40 to 60%, Co: 0.03 to 25%, Cr: 15% or more and less than 28%, either one or both of Mo: 12% or less and W: less than 4%, the total content thereof being 0.1 to 12%, Nd: 0.001 to 0.1%, B: 0.0005 to 0.006%, N: 0.03% or less, O: 0.03% or less, at least one selected from Al: 3% or less, Ti: 3% or less, and Nb: 3% or less, the balance being Fe and impurities. The contents of P and S in the impurities being P: 0.03% or less and S: 0.01% or less. The alloy satisfies 1?4×Al+2×Ti+Nb?12 and P+0.2×Cr×B?0.035, is excellent in weld crack resistance and toughness of HAZ, and is further excellent in creep strength at high temperatures.

Abstract: A high strength, ductile, and tough Ni-base heat resistant alloy comprises by mass percent, C: 0.1% or less, Si: 1% or less, Mn: 1% or less, Cr: not less than 15% to less than 28%, Fe: 15% or less, W: more than 5% to not more than 20%, Al: more than 0.5% to not more than 2%, Ti: more than 0.5% to not more than 2%, Nd: 0.001 to 0.1% and B: 0.0005 to 0.01%, with the balance being Ni and impurities. Impurity contents of P, S, Sn, Pb, Sb, Zn and As are P: 0.03% or less, S: 0.01% or less, Sn: 0.020% or less, Pb: 0.010% or less, Sb: 0.005% or less, Zn: 0.005% or less and As: 0.005% or less, and formulas of [0.015?Nd+13.4×B?0.13], [Sn+Pb?0.025] and [Sb+Zn +As?0.010] are met.

Abstract: [Problem to be Solved] A Ni-based alloy product consisting of, by mass percent, C: 0.03 to 0.10%, Si: 0.05 to 1.0%, Mn: 0.1 to 1.5%, Sol.Al: 0.0005 to 0.04%, Fe: 20 to 30%, Cr: not less than 21.0% and less than 25.0%, W: exceeding 6.0% and not more than 9.0%, Ti: 0.05 to 0.2%, Nb: 0.05 to 0.35%, and B: 0.0005 to 0.006%, the balance being Ni and impurities, the impurities being P: 0.03% or less, S: 0.01% or less, N: less than 0.010%, Mo: less than 0.5%, and Co: 0.8% or less, wherein a value of effective B (Beff) defined by the formula, Beff (%)=B?(11/14)×N+(11/48)×Ti, is 0.0050 to 0.0300%, and the rupture elongation in a tensile test at 700° C. and at a strain rate of 10?6/sec is 20% or more. This alloy may contain one or more kinds of Cu, Ta, Zr, Mg, Ca, REM, and Pd.

Abstract: A Ni-base heat resistant alloy, which comprises by mass percent, C: 0.1% or less, Si: 1% or less, Mn: 1% or less, Cr: not less than 15% to less than 28%, Fe: 15% or less, W: more than 5% to not more than 20%, Al: more than 0.5% to not more than 2%, Ti: more than 0.5% to not more than 2%, Nd: 0.001 to 0.1% and B: 0.0005 to 0.01%, with the balance being Ni and impurities, in which the contents of P, S, Sn, Pb, Sb, Zn and As among the impurities are P: 0.03% or less, S: 0.01% or less, Sn: 0.020% or less, Pb: 0.010% or less, Sb: 0.005% or less, Zn: 0.005% or less and As: 0.005% or less, and further satisfies the formulas of [0.015?Nd+13.4×B?0.13], [Sn+Pb?0.025] and [Sb+Zn+As?0.010] is an alloy in which much higher strength than the conventional Ni-base heat resistant alloy can be achieved, the ductility and toughness after a long period of use at a high temperature are remarkably improved, and moreover the zero ductility temperature and the hot workability are also further improved.

Abstract: An austenitic heat resistant alloy, which comprises, by mass percent, C?0.15%, Si?2%, Mn?3%, Ni: 40 to 80%, Cr: 15 to 40%, W and Mo: 1 to 15% in total content, Ti?3%, Al?3%, N?0.03%, O?0.03%, with the balance being Fe and impurities, and among the impurities P?0.04%, S?0.03%, Sn?0.1%, As?0.01%, Zn?0.01%, Pb?0.01% and Sb?0.01%, and satisfies the conditions [P1=S+{(P+Sn)/2}+{(As+Zn+Pb+Sb)/5}?0.050], [0.2?P2=Ti+2Al?7.5?10×P1], [P2?9.0?100×O] and [N?0.002×P2+0.019] can prevent both the liquation crack in the HAZ and the brittle crack in the HAZ and also can prevent defects due to welding fabricability, which occur during welding fabrication, and moreover has excellent creep strength at high temperatures. Therefore, the alloy can be used suitably as a material for constructing high temperature machines and equipment, such as power generating boilers, plants for the chemical industry and so on.