Jfe Steel Corporation

Tetsuyuki Nakamura

Hiroki Ota

Chikara Kami

Shin Ishikawa

Reiko Sugihara

Takumi Ujiro

Yasushi Kato

Kunio Fukuda

Hiroyuki Ogata

Manami Ichikawa

Mitsuyuki Fujisawa

Takayoshi Yano

Masataka Yoshino

Norimasa Hirata

Takashi Samukawa

Muhammad Febry

Having a chemical composition (1) containing 0.15 mass % to 1.00 mass % of Nb, and (2) containing 0.0005 mass % to 0.0100 mass % of Mg, where (3) the Al content is controlled in a range of 0.55 mass % to 2.00 mass %, and (4) a relationship of 0.0004≤[Mg]/[Al]≤0.0050 is further satisfied.

Ferritic stainless steel for solid oxide fuel cell

Provided is a ferritic stainless steel having excellent brazability and excellent corrosion resistance to condensed water in an environment in which the ferritic stainless steel is used for an exhaust heat recovery device or an EGR cooler. The ferritic stainless steel has a composition containing, in mass %, C: 0.025% or less, Si: 0.01% or more and less than 0.40%, Mn: 0.05 to 1.5%, P: 0.05% or less, S: 0.01% or less, Cr: 17.0 to 30.0%, Mo: 1.10 to 3.0%, Ni: more than 0.80% and 3.0% or less, Nb: 0.20 to 0.80%, Al: 0.001 to 0.10%, and N: 0.025% or less, with the balance being Fe and incidental impurities, and satisfying the following expression (1) and expression (2):C+N&#x2264;0.030%&#x2003;&#x2003;(1)Cr+Mo&#x2265;19.0%&#x2003;&#x2003;(2)

Ferritic stainless steel

Provided is ferritic stainless steel having excellent brazeability and excellent corrosion resistance to condensed water in an environment in which the steel is used for an exhaust heat recovery device or an EGR cooler. A ferritic stainless steel has a chemical composition containing, by mass %, C: 0.025% or less, Si: 0.40% to 2.0%, Mn: 0.05% to 1.5%, P: 0.05% or less, S: 0.01% or less, Cr: 16.0% to 30.0%, Mo: 0.60% to 3.0%, Ni: 0.10% to 2.5%, Nb: 0.20% to 0.80%, Al: 0.001% to 0.15%, N: 0.025% or less, and the balance being Fe and inevitable impurities, in which relational expressions (1) and (2) below are satisfied.C+N&#x2264;0.030%&#x2003;&#x2003;(1),2Si+Ni&#x2265;1.0%&#x2003;&#x2003;(2),(in relational expressions (1) and (2), C, N, Si, and Ni each denote the contents (mass %) of the corresponding elements).

A martensitic stainless steel sheet comprises a chemical composition containing, in mass %, C: 0.035% to 0.090%, Si: 0.01% to 1.0%, Mn: 0.01% to 0.90%, P: 0.050% or less, S: 0.050% or less, Cr: 10.0% to 14.0%, Ni: 0.01% to 0.40%, Al: 0.001% to 0.50%, V: 0.05% to 0.50%, and N: 0.050% to 0.20%, with the balance being Fe and inevitable impurities, wherein a content of C and a content of N in the chemical composition satisfy C %+N % 0.10% and N % C %, the number of precipitates with a major axis length of 200 nm or more in a surface layer of the martensitic stainless steel sheet is 25 or less per 100 &#x3bc;m, and the martensitic stainless steel sheet has a tensile strength of 1300 MPa or more, a proof stress of 1100 MPa or more, and an elongation of 8.0% or more.

Martensitic stainless steel sheet

A martensitic stainless steel has a chemical composition containing, by mass %, C: 0.030% or more and less than 0.20%, Si: 0.01% or more and 2.0% or less, Mn: 0.01% or more and 3.0% or less, P: 0.050% or less , S: 0.010% or less, Cr: 10.0% or more and 16.0% or less, Ni: 0.01% or more and 0.80% or less, Al: 0.001% or more and 0.50% or less, Zr: 0.005% or more and 0.50% or less, and N: 0.030% or more and less than 0.20%, with the balance consisting of Fe and inevitable impurities.

Provided is a ferritic stainless steel excellent in oxidation resistance and thermal fatigue resistance. The ferritic stainless steel contains, in mass %, C: 0.020% or less, Si: more than 0.1% and 3.0% or less, Mn: 0.05 to 2.0%, P: 0.050% or less, S: 0.010% or less, Al: 0.3 to 6.0%, N: 0.020% or less, Cr: 12 to 30%, Nb: more than 0.3% and 1.0% or less, Ti: 0.01 to 0.5%, Mo: 0.3 to 6.0%, Co: 0.01 to 3.0%, and Ni: 0.02 to 1.0%, the balance being Fe and unavoidable impurities. Moreover, Si+Al&#x3e;1.0%, Al&#x2014;Mn&#x3e;0%, and Nb&#x2014;Ti&#x3e;0% hold.

A hot rolled and annealed ferritic stainless steel sheet includes a composition that contains, on a mass percent basis, 0.015% or less of C, 1.00% or less of Si, 1.00% or less of Mn, 0.040% or less of P, 0.010% or less of S, 12.0% or more and 23.0% or less of Cr, 0.20% or more and 1.00% or less of Al, 0.020% or less of N, 1.00% or more and 2.00% or less of Cu, and 0.30% or more and 0.65% or less of Nb, Si and Al being contained so as to satisfy expression (1) described below, the balance being Fe and incidental impurities, and the hot rolled and annealed ferritic stainless steel sheet having a Vickers hardness less than 205, Si&#x2265;Al (1) (where in expression (1), Si represents the content of Si (% by mass), and Al represents the content of Al (% by mass)).

Hot rolled and annealed ferritic stainless steel sheet, method of producing same, and cold rolled and annealed ferritic stainless steel sheet

The disclosure is to provide a martensitic stainless steel excellent in strength, workability and corrosion resistance. The martensitic stainless steel comprises a chemical composition containing, in mass %: C: 0.020% or more and less than 0.10%, Si: 0.01% or more and 2.0% or less, Mn: 0.01% or more and 3.0% or less, P: 0.050% or less, S: 0.050% or less, Cr: 10.0% or more and 16.0% or less, Ni: 0.01% or more and 0.80% or less, Al: 0.001% or more and 0.50% or less, and N: more than 0.050% and 0.20% or less, satisfying N % C %, and the balance containing Fe and incidental impurities, where C % and N % indicate respectively the contents of C and N (mass %) in the steel.

Martensitic stainless steel

A ferritic stainless steel having excellent thermal fatigue resistance, excellent oxidation resistance, and excellent high-temperature fatigue resistance is provided. The ferritic stainless steel contains, in terms of % by mass, C: 0.020% or less, Si: 3.0% or less, Mn: 2.0% or less, P: 0.040% or less, S: 0.030% or less, Cr: 10.0% to 20.0%, N: 0.020% or less, Nb: 0.005% to 0.15%, Al: 0.20% to 3.0%, Ti: 5&#xd7; (C+N)% to 0.50%, Cu: 0.55% to 1.60%, B: 0.0002% to 0.0050%, Ni: 0.05% to 1.0%, 0: 0.0030% or less, and the balance being Fe and unavoidable impurities. Additionally, the ferritic stainless steel satisfies that Al/O&#x2265;100.

A ferritic stainless steel that a composition including in terms of % by mass, C: 0.015% or less, Si: 1.0% or less, Mn: 1.0% or less, P: 0.040% or less, S: 0.010% or less, Cr: 10.0% to 23.0%, Al: 0.2% to 1.0%, N: 0.015% or less, Cu: 1.0% to 2.0%, Nb: 0.30% to 0.65%, Ti: 0.50% or less, O: 0.0030% or less, and the balance being Fe and unavoidable impurities, wherein a Si content and an Al content satisfy Si&#x2265;Al, and the Al content and an O content satisfy Al/O&#x2265;100.

Provided is a ferritic stainless steel excellent in terms of thermal fatigue resistance and oxidation resistance without adding Mo or W, which is an expensive chemical element and with controlling the Nb content to be as small as possible. The chemical composition contains, by mass %, C: 0.020% or less, Si: 3.0% or less, Mn: 3.0% or less, P: 0.040% or less, S: 0.030% or less, Cr: 10% to 25%, N: 0.020% or less, Nb: 0.005% to 0.15%, Al: less than 0.20%, Ti: 5&#xd7;(C %+N %) to 0.5%, Mo: 0.1% or less, W: 0.1% or less, Cu: 0.55% to 2.0%, B: 0.0002% to 0.0050%, Ni: 0.05% to 1.0%, and the balance being Fe and inevitable impurities, where C % and C5 in the expression 5&#xd7;(C %+N %) respectively represent the contents (mass %) of the chemical elements C and N.

Provided is a ferritic stainless steel excellent in terms of thermal fatigue resistance, high-temperature fatigue resistance and oxidation resistance without adding Mo or W, which is an expensive chemical element and with controlling Nb content to be as small as possible. The chemical composition contains, by mass %, C: 0.020% or less, Si: 3.0% or less, Mn: 3.0% or less, P: 0.040% or less, S: 0.030% or less, Cr: 10% to 25%, N: 0.020% or less, Nb: 0.005% to 0.15%, Al: 0.20% to 3.0%, Ti: 5&#xd7;(C %+N %) to 0.5%, Mo: 0.1% or less, W: 0.1% or less, Cu: 0.55% to 2.0%, B: 0.0002% to 0.0050%, Ni: 0.05% to 1.0%, and the balance being Fe and inevitable impurities, where C % and N % in the expression 5&#xd7;(C %+N %) respectively represent the contents (mass %) of the chemical elements C and N.

Ferritic stainless steel is excellent in terms of both oxidation resistance and thermal fatigue resistance without adding expensive elements, such as Mo or W. The ferritic stainless steel, contains: C: 0.015 mass % or lower, Si: 1.0 mass % or lower, Mn: 1.0 mass % or lower, P: 0.04 mass % or lower, S: 0.010 mass % or lower, Cr: 16 to 23 mass % or lower, N: 0.015 mass % or lower, Nb: 0.3 to 0.65 mass %, Ti: 0.15 mass % or lower, Mo: 0.1 mass % or lower, W: 0.1 mass % or lower, Cu: 1.0 to 2.5 mass %, Al: 0.2 to 1.5 mass %, and the balance of Fe and inevitable impurities.

Heat-resistance ferritic stainless steel

An object is to provide a ferritic stainless steel having excellent oxidation resistance, while preventing a deterioration in formability, without adding expensive chemical elements such as Mo and W. Specifically, the ferritic stainless steel excellent in oxidation resistance having a chemical composition containing, by mass %, C: 0.015% or less, Si: 0.40% or more and 1.00% or less, Mn: 1.00% or less, P: 0.040% or less, S: 0.010% or less, Cr: 12.0% or more and 23.0% or less, N: 0.015% or less, Nb: 0.30% or more and 0.65% or less, Ti: 0.150% or less, Mo: 0.10% or less, W: 0.10% or less, Cu: less than 1.00%, Al: 0.20% or more and 1.00% or less, while the relationship Si&#x2267;Al is satisfied, and the balance being Fe and inevitable impurities.

Ferritic stainless steel excellent in oxidation resistance

A ferritic stainless steel contains no expensive elements such as Mo and W, is free from the oxidation resistance loss caused by addition of Cu, and thereby has excellent levels of oxidation resistance (including water vapor oxidation resistance), thermal fatigue property, and high-temperature fatigue property. The ferritic stainless steel contains, in mass %, C at 0.015% or less, Si at 0.4 to 1.0%, Mn at 1.0% or less, P at 0.040% or less, S at 0.010% or less, Cr at 16 to 23%, Al at 0.2 to 1.0%, N at 0.015% or less, Cu at 1.0 to 2.5%, Nb at 0.3 to 0.65%, Ti at 0.5% or less, Mo at 0.1% or less, and W at 0.1% or less, the Si and the Al satisfying a relation Si (%)&#x2267;Al (%).

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Tokyo, Japan

Tetsuyuki Nakamura