Sumitomo Metal Industries, Inc.

Mitsubishi Jukogyo Kabushiki Kaisha

Nippon Steel Sumitomo Metal Corporation

Nippon Steel Corporation

Mitsubishi Hitachi Power Systems, Ltd.

Atsuro Iseda

Hiroyuki Semba

Hiroyuki Hirata

Hirokazu Okada

Fujimitsu Masuyama

Yoshiatsu Sawaragi

Tomomitsu Yokoyama

Kaori Kawano

Takashi Nakashima

Osamu Miyahara

Hisao Haneda

Mitsuru Yoshizawa

Takashi Daikoku

Hiroshi Teranishi

Masaaki Igarashi

Tetsuo Yokoyama

Kazuhiro Ogawa

Takeshi Miki

Kana Jotoku

Toshihide Ono

Kunihiko Yoshikawa

Katsuki Tanaka

Shunichi Otsuka

Takuya Hanada

Tomoaki Hamaguchi

Tadashi Kawakami

Kunihiko Yoshikama

Fujimitsu Mausyama

Kana Joutoku

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 &#x3c;&#xd7;()&#xd7;/(2&#x3c0;&#xd7;)&#x3c;0.26&#x2003;&#x2003;(1)0.83&#x3c;&#xd7;()&#xd7;/(2&#xd7;)&#x3c;2.0&#x2003;&#x2003;(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.

Method for producing a rifled tube

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.

High Cr-based austenitic stainless steel

A Ni-based heat resistant alloy as pipe, plate, rod, forgings and the like consists of C&#x2266;0.15%, Si&#x2266;2%, Mn&#x2266;3%, P&#x2266;0.03%, S&#x2266;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&#x2266;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&#xd7;10d+0.05{(Al/26.98)+(Ti/47.88)+(Nb/92.91)}. In the formula, d denotes an average grain size (&#x3bc;m), and each element symbol denotes the content (mass %) of that element. If the alloy contains W, Mo+(W/2)&#x2266;15% holds. The alloy has improved ductility after long-term use at high temperatures, and cracking due to welding can be avoided.

Ni-based heat resistant alloy

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 &#x3bc;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.

Double-walled tube with interface gap and production method therefor

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&#x2266;4&#xd7;Al+2&#xd7;Ti+Nb&#x2266;12 and P+0.2&#xd7;Cr&#xd7;B&#x2266;0.035, where an element in the Formulas represents the content by mass percent.

Austenitic heat resistant alloy

[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&#x2212;(11/14)&#xd7;N+(11/48)&#xd7;Ti, is 0.0050 to 0.0300%, and the rupture elongation in a tensile test at 700&#xb0; C. and at a strain rate of 10/sec is 20% or more. This alloy may contain one or more kinds of Cu, Ta, Zr, Mg, Ca, REM, and Pd.

Ni-based alloy product and producing method thereof

An austenitic heat resistant alloy, which contains, by mass percent, C&#x2266;0.15%, Si&#x2266;2%, Mn&#x2266;3%, Ni: 40 to 80%, Cr: 15 to 40%, W and Mo: 1 to 15% in total content, Ti&#x2266;3%, Al&#x2266;3%, N&#x2266;0.03%, O&#x2266;0.03%, with the balance being Fe and impurities, and among the impurities P&#x2266;0.04%, S&#x2266;0.03%, Sn&#x2266;0.1%, As&#x2266;0.01%, Zn&#x2266;0.01%, Pb&#x2266;0.01% and Sb&#x2266;0.01%, and satisfies the conditions [P1=S+{(P+Sn)/2}+{(As+Zn+Pb+Sb)/5}&#x2266;0.050], [0.2&#x2266;P2=Ti+2Al&#x2266;7.5&#x2212;10&#xd7;P1], [P2&#x2266;9.0&#x2212;100&#xd7;O] and [N&#x2266;0.002&#xd7;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. The ally may contain a specific amount or amounts of one or more elements selected from Co, B, Ta, Hf, Nb, Zr, Ca, Mg, Y, La, Ce and Nd.

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&#x2266;Nd+13.4&#xd7;B&#x2266;0.13], [Sn+Pb&#x2266;0.025] and [Sb+Zn +As&#x2266;0.010] are met.

Ni-base heat resistant alloy

The present invention provides an austenitic stainless steel tube with a uniform fine grained structure of regular grains, which is not changed to a coarse structure and the steam oxidation resistance is maintained even if the tube is subjected to a high temperature reheating during welding and high temperature bending working. The austenitic stainless steel tube consists of, by mass %, C: 0.03&#x2013;0.12%, Si: 0.1&#x2013;0.9%, Mn: 0.1&#x2013;2%, Cr: 15&#x2013;22%, Ni: 8&#x2013;15%, Ti: 0.002&#x2013;0.05%, Nb: 0.3&#x2013;1.5%, sol. Al: 0.0005&#x2013;0.03%, N: 0.005&#x2013;0.2% and O (oxygen): 0.001&#x2013;0.008%, and the balance Fe and impurities, the austenitic stainless steel tube having austenitic grain size number of 7 or more and a mixed grain ratio of preferably 10% or less.

Austenitic stainless steel tube excellent in steam oxidation resistance and a manufacturing method thereof

An austenitic stainless steel excellect in high temperature strength and creep rupture ducitility which comprises, on the percent by mass basis, C: 0.03-0.12%, Si: 0.2-2%, Mn: 0.1-3%, P: 0.03% or less, S: 0.01% or less, Ni: more than 18% and less than 25%, Cr: more than 22% and less than 30%, Co: 0.04-0.8%, Ti: 0.002% or more and less than 0.01%, Nb: 0.1-1%, V: 0.01-1%, B: more than 0.0005% and 0.2% or less, sol. Al: 0.0005% or more and less than 0.03%, N: 0.1-0.35% and O (Oxygen): 0.001-0.008%, with the balance being Fe and impurities. The austenitic stainless steel may contain a specified amount of one or more element(s) of Mo and W, and/or a specified amount of one or more element(s) of Mg, Zr, Ca, REM, Pd and Hf.

Austenitic stainless steel and manufacturing method thereof

An austenitic stainless steel suited for ultra supercritical boilers, which consists of C: 0.03-0.12%, Si: 0.1-1%, Mn: 0.1-2%, Cr: not less than 20% but less than 28%, Ni: more than 35% but not more than 50%, W: 4-10%, Ti: 0.01-0.3%, Nb: 0.01-1%, sol. Al: 0.0005-0.04%, B: 0.0005-0.01%, and the balance Fe and impurities; and also characterized by the impurities whose contents are restricted to P: not more than 0.04%, S: not more than 0.010%, Mo: less than 0.5%, N: less than 0.02%, and O (oxygen): not more than 0.005%. Heat resistant pressurized parts excellent in thermal fatigue properties and structural stability at high temperatures, which have a coarse grain whose grain size number is 6 or less, and whose mixed grain ratio is 10% or less.

Austenitic stainless steel excellent in high temperature strength and corrosion resistance, heat resistant pressurized parts, and the manufacturing method thereof

A low-Cr ferritic steel with improved toughness as well as creep strength is disclosed, which consists essentially of, by weight %:

Low-chromium ferritic heat-resistant steel with improved toughness and

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.

High-chromium ferritic, heat-resistant steel having improved resistance

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:

Low-alloy heat-resistant steel having improved creep strength and

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 %:

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Kobe, Japan

Atsuro Iseda