Abstract: A method for producing an austenitic heat resistant steel in which a difference between a content of Nb and an amount of Nb analyzed as extraction residues satisfies [0.170?Nb?NbER?0.480], the method including: a forming step of machining and forming a steel having a predetermined chemical composition into a product shape; a solution heat treatment step of performing, after the forming step, heat treatment under conditions including a heat treatment temperature satisfying [?250Nb+1200?T??100Nb+1290] and a soaking time satisfying [405?0.3T?t?2475?1.5T]; and a cooling step of performing cooling after the solution heat treatment step.

Abstract: There is provided a duplex stainless steel tube including a chemical composition consisting of, in mass %, C: 0.008 to 0.030%, Si: 0.10 to 0.70%, Mn: 0.80 to 2.60%, P: 0.030% or less, S: 0.0001 to 0.0050%, O: 0.0004 to 0.0150%, Sn: 0.0001% or more to less than 0.0100%, Cu: 0.10 to 2.50%, Ni: more than 2.50 to 5.50% or less, Cr: 21.5 to 25.5%, Mo: 0.10 to 0.50%, N: 0.050 to 0.200%, Al: 0.200% or less, and optional elements, with the balance: Fe and impurities, wherein 4S+8O+Sn is 0.0040 to 0.0900, and 4S+Sn is 0.0180 or less.

Abstract: There is provided an austenitic heat resistant steel including a chemical composition that consists of, in mass %, C: 0.04 to 0.12%, Si: 0.01 to 0.30%, Mn: 0.50 to 1.50%, P: 0.001 to 0.040%, S: less than 0.0050%, Cu: 2.2 to 3.8%, Ni: 8.0 to 11.0%, Cr: 17.7 to 19.3%, Mo: 0.01 to 0.55%, Nb: 0.400 to 0.650%, B: 0.0010 to 0.0060%, N: 0.050 to 0.160%, Al: 0.025% or less, and O: 0.020% or less, with the balance: Fe and impurities and that satisfies [0.170?Nb?NbER?0.480].

Abstract: An austenitic heat resisting steel includes, as a chemical composition, by mass %: C: 0.04% to 0.12%; Si: 0.10% to 0.30%; Mn: 0.20% to 0.80%; P: 0% to 0.030%; S: 0.0001% to 0.0020%: Sn: 0.0005% to 0.0230%; Cu: 2.3% to 3.8%; Co: 0.90% to 2.40%; Ni: 22.0% to 28.0%; Cr: 20.0% to 25.0%; Mo: 0.01% to 0.40%; W: 2.8% to 4.2%; Nb: 0.20% to 0.80%; B: 0.0010% to 0.0050%; and N: 0.16% to 0.30%, and a remainder of Fe and impurities, optionally further includes one or more selected from Al, O, V, Ti, Ta, C, Mg, and REM, in which 0.0012%?[% S]+[% Sn]?2.5×[% B]+0.0125% is satisfied.

Abstract: A ferritic heat-resistant steel includes, by mass: from 0.06 to 0.11% of C; from 0.15 to 0.35% of Si; from 0.35 to 0.65% of Mn; from 0 to 0.02% of P; from 0 to 0.003% of S; from 0.005 to 0.25% of Ni; from 0.005 to 0.25% of Cu; from 2.7 to 3.3% of Co; from 8.3 to 9.7% of Cr; from 2.5 to 3.5% of W; from 0.15 to 0.25% of V; from 0.03 to 0.08% of Nb; from 0.002 to 0.04% of Ta; from 0.01 to 0.06% of Nd; from 0.006 to 0.016% of B; from 0.005 to 0.015% of N; from 0 to 0.02% of Al; and from 0 to 0.02% of O, with a balance consisting of Fe and impurities, and an amount of W, which is analyzed as an electrolytically extracted residue, [% W]ER, satisfying: ?10×[% B]+0.26?[% W]ER?10×[% B]+0.54.

Abstract: Provided is an austenitic heat resistant alloy having a chemical composition consisting of, in mass %: C: 0.02 to 0.12%; Si: 2.0% or less; Mn: 3.0% or less; P: 0.030% or less; S: 0.015% or less; Cr: 20.0% or more and less than 28.0%; Ni: more than 35.0% and 55.0% or less; Co: 0 to 20.0%; W: 4.0 to 10.0%; Ti: 0.01 to 0.50%; Nb: 0.01 to 1.0%; Mo: less than 0.50%; Cu: less than 0.50%; Al: 0.30% or less; N: less than 0.10%; Mg: 0 to 0.05%; Ca: 0 to 0.05%; REM: 0 to 0.50%; V: 0 to 1.5%; B: 0 to 0.01%; Zr: 0 to 0.10%; Hf: 0 to 1.0%; Ta: 0 to 8.0%; Re: 0 to 8.0%; and the balance: Fe and impurities, wherein a shortest distance from a center portion to an outer surface portion of a cross section of the alloy is 40 mm or more, the cross section being perpendicular to a longitudinal direction of the alloy, an austenite grain size number at the outer surface portion is ?2.0 to 4.0, an amount of Cr which is present as a precipitate satisfies [CrPB/CrPS?10.0], and [YSS/YSB?1.5] and [TSS/TSB?1.

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: There is provided an austenitic stainless steel pipe excellent in steam oxidation resistance. The austenitic stainless steel pipe excellent in steam oxidation resistance contains, by mass percent, 14 to 28% of Cr and 6 to 30% of Ni, and is configured so that a region satisfying the following Formula exists in a metal structure at a depth of 5 to 20 ?m from the inner surface of the steel pipe: (?/?)×?/?×100?0.3 where the meanings of symbols in the above Formula are as follows: ?: sum total of the number of pixels of digital image in region in which orientation difference of adjacent crystals detected by electron backscattering pattern is 5 to 50 degrees ?: the number of total pixels of digital image in region of measurement using electron backscattering pattern ?: analysis pitch width of electron backscattering pattern (?m) ?: grain boundary width (?m).

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: 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: 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: There is provided an austenitic stainless steel pipe excellent in steam oxidation resistance. The austenitic stainless steel pipe excellent in steam oxidation resistance contains, by mass percent, 14 to 28% of Cr and 6 to 30% of Ni, and is configured so that a region satisfying the following Formula exists in a metal structure at a depth of 5 to 20 ?m from the inner surface of the steel pipe: (?/?)×?/?×100?0.3 where the meanings of symbols in the above Formula are as follows: ?: sum total of the number of pixels of digital image in region in which orientation difference of adjacent crystals detected by electron backscattering pattern is 5 to 50 degrees ?: the number of total pixels of digital image in region of measurement using electron backscattering pattern ?: analysis pitch width of electron backscattering pattern (?m) ?: grain boundary width (?m).

Abstract: A method for surface treating a mandrel bar used for hot rolling of high-alloy seamless steel pipe is provided. The method includes heat treating the mandrel bar to develop a scale, and after heat treatment, rolling ordinary steel comprising 8% or less of chromium for at least 50 passes. This achieves a mandrel bar for rolling high-alloy steel possessing both durability and superior resistance to seizure.

Abstract: There is provided a heat resistant ferritic steel, excellent in the weld crack resistance of the HAZ and creep strength. A high-Cr heat resistant ferritic steel is characterized by consisting of, by mass %, Si: more than 0.1% and not more than 1.0%, Mn: 2.0% or less, Co: 1 to 8%, Cr: 7 to 13%, V: 0.05 to 0.4%, Nb: 0.01 to 0.09%, either one or both of Mo and W: 0.5 to 4% as a total, B: 0.005 to 0.025%, Al: 0.03% or less, and N: 0.003 to 0.06%, and containing C in an amount satisfying Expression (1), the balance being Fe and impurities, and O, P and S as impurities being such that O: 0.02% or less, P: 0.03% or less, and S: 0.02% or less, respectively, 0.005?C?(?5/3)×B+0.085??(1) in which C and B represent the content of each element (mass %). Furthermore, the high-Cr heat resistant ferritic steel may contain one or more kinds selected from the group consisting of Nd, Ta, Ca and Mg.

Abstract: A martensitic stainless steel provided includes C: 0.01-0.1% and Cr: 9-15%, and the retained austenite phase has a thickness not more than 100 nm in such a manner that the X-ray integral intensities of 111? and 110? satisfy the following formula (a): 0.005?111?/(111?+110?)?0.05??(a) Such a metal structure can be obtained by the following procedure: the steel is heated at a temperature of the Ac3 point or more, and then cooled from 800° C. to 400° C. at a cooling rate of not less than 0.08° C./sec and further cooled down to 150° C. at a cooling rate of not more than 1° C./sec. The martensitic stainless steel according to the present invention has a relatively high carbon content and a greater toughness in spite of a high mechanical strength, and further exhibits an excellent corrosion resistance, so that it is particularly effective as the material for constructing a deep oil well.

Abstract: A method for surface treating a mandrel bar used for hot rolling of high-alloy seamless steel pipe is provided. The method includes heat treating the mandrel bar to develop a scale, and after heat treatment, rolling ordinary steel comprising 8% or less of chromium for at least 50 passes.

Abstract: Heat-resistant steel excellent in high-temperature long-term creep strength and creep-fatigue strength is provided. This heat-resistant steel comprises C: 0.01 to 0.13%, Si: 0.15 to 0.50%, Mn: 0.2 to 0.5%, P: not higher than 0.02%, S; not higher than 0.005%, Cr: exceeding 8.0% but lower than 12.0%, Mo: 0.1 to 1.5%, W: 1.0 to 3.0%, V: 0.1 to 0.5%, Nb: 0.02 to 0.10%, sol. Al: not higher than 0.015%, N: 0.005 to 0.070%, Nd: 0.005 to 0.050% and B: 0.002 to 0.015%, with the balance Fe and impurities; the content of Ni is lower than 0.3%, the content of Co is lower than 0.3% and the content of Cu is lower than 0.1% among the impurities; the steel contains Nd inclusions at a Nd inclusion density of not lower than 10000 inclusions/mm3. This steel may contain, in addition to the above-specified components, one or more elements of Ta, Hf, Ti, Ca and Mg.

Abstract: A martensitic stainless steel provided includes C: 0.01-0.

Abstract: A rectangular faceplate panel of a color picture tube of the shadow mask type. In the periphery of the rectangular faceplate panel, a curvature C.sub.PL at a long side peripheral portion is made larger than a curvature C.sub.PS at a short side peripheral portion by a value within a range of from 10% to 100%. Further, a level difference z of a diagonal axis of the rectangular faceplate panel is selected to be large and an average radius of curvature in the diagonal direction of the rectangular faceplate panel is selected to be small. Thus, in the color picture tube of the shadow mask type, the faceplate of can be made to look flat, the doming phenomenon can be improved, and sufficient mechanical strength of the glass envelope can be obtained.