Jfe Steel Corporation

Kawasaki Steel Corporation

Yoshihiro Yazawa

Osamu Furukimi

Yasushi Kato

Mineo Muraki

Yoshihiro Ozaki

Keiichi Yoshioka

Kunio Fukuda

Susumu Satoh

Atsushi Miyazaki

Junichiro Hirasawa

Takumi Ujiro

Fusao Togashi

Noboru Kinoshita

Sadao Hasuno

Makoto Kobayashi

Hiroki Ota

Mitsuyuki Fujisawa

Tomoyuki Yokota

Kimihiro Nishimura

Shinji Mitao

Yuji Sone

Keiichiro Kishi

Toshiyuki Hoshino

Shunichi Tachibana

Masayuki Hino

Yota Kuronuma

Hitoshi Sueyoshi

Yukihiro Baba

Masayuki Kasai

Shintaro Kumazawa

Satoshi Owada

Yasushi Katoh

Atushi Miyazaki

Disclosed is a manufacturing method for a seawater-resistant stainless clad steel including a cladding material made of stainless steel having a pitting index represented by Cr[mas %]+3.3Mo[mass %]+16N[mass %], of 35.0 or more and a microstructure in a surface portion thereof including, by area ratio, less than 2.0% of a &#x3c3; phase. The method including the steps of performing a mechanical treatment from at least one of grindstone polishing and belt polishing and performing at least one of an electrolytic treatment in acid solutions or in neutral salt solutions, and a pickling treatment, to manufacture the stainless clad steel having dynamic friction coefficients in the rolling direction and in a direction at a right angle to the rolling direction, determined in accordance with JIS K 7125, both of 0.05 or less.

Seawater-resistant stainless clad steel

A cladding material for stainless steel clad steel plate, includes, by mass %, 0.03% or less carbon, 1.5% or less silicon, 2.0% or less manganese, 0.04% or less phosphorus, 0.03% or less sulfur, 22.0% to 25.0% nickel, 21.0% to 25.0% chromium, 2.0% to 5.0% molybdenum, 0.15% to 0.25% nitrogen, and the balance being iron and incidental impurities, wherein critical pitting temperature (CPT) after normalization as determined in accordance with ASTM G48-03 Method E is 45&#xb0; C. or higher, and corrosion loss at a welded zone as determined by a corrosion test in accordance with NORSOK Standard M-601 is 1.0 g/mor less.

Stainless steel clad steel plate including cladding material for stainless steel clad steel plate and method of manufacturing the same

The soft Cr-containing steel includes, on a % by mass basis, C: from about 0.001% to about 0.020%, Si: more than about 0.10% and less than about 0.50%, Mn: less than about 2.00%, P: less than about 0.060%, S: less than about 0.008%, Cr: from about 12.0% to about 16.0%, Ni: from about 0.05% to about 1.00%, N: less than about 0.020%, Nb: from about 10&#xd7;(C+N) to about 1.00%, Mo: more than about 0.80% and less than about 3.00%, wherein the contents of alloying elements, represented by Si and Mo, respectively, on a % by mass, satisfy the formula Si&#x2266;1.2-0.4 Mo, so as to prevent precipitation of the Laves phase and to stably secure an effect of increasing high-temperature strength due to solid solution Mo.

Soft Cr-containing steel

A low Ni and high N austenitic-ferritic stainless steel is disclosed. It includes an austenitic-ferritic stainless steel having high formability and punch stretchability, crevice corrosion resistance, corrosion resistance at welded part, or excellent intergranular corrosion resistance, from a stainless steel structured by mainly austenite phase and ferrite phase, and consisting essentially of 0.2% or less C, 4% or less Si, 12% or less Mn, 0.1% or less P, 0.03% or less S, 15 to 35% Cr, 3% or less Ni, and 0.05 to 0.6% N, by mass, by adjusting the percentage of the austenite phase in a range from 10 to 85%, by volume. Furthermore, it includes an austenitic-ferritic stainless steel having higher formability by adjusting the amount of (C+N) in the austenite phase to a range from 0.16 to 2% by mass.

Austenitic-ferritic stainless steel

A Ti-containing ferritic stainless steel sheet and a manufacturing method thereof include stainless steels being formed while a refining load is decreased and having a low yield strength which exhibits superior workability. The Ti-containing ferritic stainless steel sheet contains on mass percent basis: 0.01% or less of C; 0.5% or less of Si; 0.3% or less of Mn; 0.01% to 0.04% of P; 0.01% or less of S; 8% to 30% of Cr; 1.0% or less of Al; 0.05% to 0.5% of Ti; 0.04% or less of N, 8&#x2266;Ti/(C+N)&#x2266;30 being satisfied; and the balance being substantially Fe and incidental impurities, wherein a grain size number of ferrite grain is 6.0 or more, and an average diameter Dp of precipitation diameters, each being [(a long axis length of a Ti base precipitate+a short axis length thereof)/2], of the Ti base precipitates in the steel sheet is in the range of from 0.05 &#x3bc;m to 1.0 &#x3bc;m.

Ferritic stainless steel plate with Ti and method for production thereof

The invention provides a Fe&#x2014;Cr alloy structure containing Cr of about 6% or more by mass but about 25% or less by mass, having a corrosion-resistant paint film containing metal powder having ionization tendencies greater than iron, with a content of the metal powder of about 20% or more by volume but about 60% or less by volume in a dry paint film, with a dry film thickness of about 5 &#x3bc;m or more but about 100 &#x3bc;m or less; and a manufacturing method thereof; whereby excellent corrosion resistance and excellent adhesion is provided.

Fe-Cr alloy structure with excellent corrosion resistance and excellent adhesion, and manufacturing method thereof

The soft Cr-containing steel includes, on a % by mass basis, C: from about 0.001% to about 0.020%, Si: more than about 0.10% and less than about 0.50%, Mn: less than about 2.00%, P: less than about 0.060%, S: less than about 0.008%, Cr: from about 12.0% to about 16.0%, Ni: from about 0.05% to about 1.00%, N: less than about 0.020%, Nb: from about 10&#xd7;(C+N) to about 1.00%, Mo: more than about 0.80% and less than about 3.00%, wherein the contents of alloying elements, represented by Si and Mo, respectively, on a % by mass, satisfy the formula Si&#x2266;1.2&#x2212;0.4Mo, so as to prevent precipitation of the Laves phase and to stably secure an effect of increasing high-temperature strength due to solid solution Mo.

A ferritic stainless steel sheet contains abut 0.01 percent by mass or less of carbon; about 1.0 percent by mass or less of silicon; about 1.5 percent by mass or less of manganese; about 11 to about 23 percent by mass of chromium; about 0.06 percent by mass or less of phosphorous; about 0.03 percent by mass or less of sulfur; about 1.0 percent by mass or less of aluminum; about 0.04 percent by mass or less of nitrogen; about 0.0005 to about 0.01 percent by mass of boron; about 0.3 percent by mass or less of vanadium; about 0.8 percent by mass or less of niobium and/or about 1.0 percent by mass or less of titanium wherein 18&#x2266;Nb/(C+N)+2(Ti/(C+N))&#x2266;60; and the balance being iron and unavoidable impurities. The average crystal grain diameter is about 40 &#x3bc;m or less and the average surface roughness is about 0.3 &#x3bc;m or less.

Method of making ferritic stainless steel sheet having excellent deep-drawability and brittle resistance to secondary processing

A ferritic stainless steel sheet for use in automobile fuel tanks and fuel pipes having smooth surface and resistance to organic acid is provided. The sheet contains, by mass, not more than about 0.1% C, not more than about 1.0 Si, not more than about 1.5% Mn, not more than about 0.06% P, not more than about 0.03% S, about 11% to about 23% Cr, not more than about 2.0% Ni, about 0.5% to about 3.0% Mo, not more than about 1.0% Al, not more than about 0.04% N, at least one of not more than about 0.8% Nb and not more than about 1.0% Ti, and the balance being Fe and unavoidable impurities, satisfying the relationship: 18&#x2266;Nb/(C+N)+2Ti/(C+N)&#x2266;60, wherein C, N, Nb, and Ti in the relationship represent the C, N, Nb, and Ti contents by mass percent, respectively. A process for making the same is also provided.

Ferritic stainless steel sheet with excellent workability and method for making the same

Ferritic stainless steel sheet having excellent deep-drawability and brittle resistance to secondary processing and method for making the same

A ferritic stainless steel sheet for fuel tanks and fuel pipes comprises, by mass percent, about 0.1% or less of C; about 1.0% or less of Si; about 1.5% or less of Mn; about 0.06% or less of P; about 0.03% or less of S; about 1.0% or less of Al; about 11% to about 20% Cr; about 2.0% or less of Ni; about 0.5% to about 3.0% Mo; about 0.02% to about 1.0% V; about 0.04% or less of N; at least one of about 0.01% to about 0.8% Nb and about 0.01% to about 1.0% Ti; and the balance being Fe and incidental impurities. The ferritic stainless steel sheet is produced by rough-rolling a slab having the above composition; hot-rolling the rough-rolled sheet under a linear pressure of at least about 3.5 MN/m at a final pass in the finish rolling; cold-rolling the hot-rolled sheet at a gross reduction rate of at least about 75%; and annealing the cold-rolled sheet. The cold-rolling step includes one rolling stage or at least two rolling stages including intermediate annealing.

Ferritic stainless steel sheet for fuel tank and fuel pipe

The soft Cr-containing steel includes, on a % by mass basis, C: from about 0.001% to about 0.020%, Si: more than about 0.10% and less than about 0.50%, Mn: less than about 2.00%, P: less than about 0.060%, S: less than about 0.008%, Cr: from about 12.0% to about 16.0%, Ni: from about 0.05% to about 1.00%, N: less than about 0.020%, Nb: from about 10&times;(C&plus;N) to about 1.00%, Mo: more than about 0.80% and less than about 3.00%, wherein the contents of alloying elements, represented by Si and Mo, respectively, on a % by mass, satisfy the formula Si &lE;1.2&minus;0.4 Mo, so as to prevent precipitation of the Laves phase and to stably secure an effect of increasing high-temperature strength due to solid solution Mo.

A ferritic stainless steel sheet for use in automobile fuel tanks and fuel pipes having smooth surface and resistance to organic acid is provided. The sheet contains, by mass, not more than about 0.1% C, not more than about 1.0 Si, not more than about 1.5 % Mn, not more than about 0.06% P, not more than about 0.03% S, about 11% to about 23% Cr, not more than about 2.0% Ni, about 0.5% to about 3.0% Mo, not more than about 1.0% Al, not more than about 0.04% N, at least one of not more than about 0.8% Nb and not more than about 1.0% Ti, and the balance being Fe and unavoidable impurities, satisfying the relationship: 18&lE;Nb/(C&plus;N)&plus;2Ti/(C&plus;N)&lE;60, wherein C, N, Nb, and. Ti in the relationship represent the C, N, Nb, and Ti contents by mass percent, respectively. A process for making the same is also provided.

Ferritic stainless steel sheet with excellent workability

Fe-Cr alloy having excellent initial rust resistance, workability and weldability

A ferritic stainless steel sheet having less planar anisotropy and excellent anti-ridging characteristics is disclosed. The sheet includes not more than about 0.02 wt % of C, about 0.01-1.0 wt % of Si, about 0.01-1.0 wt % of Mn, not more than about 0.08 wt % of P, not more than about 0.01 wt % of S, about 0.005-0.30 wt % of Al, about 11-50 wt % of Cr, about 0.1-5.0 wt % of Mo, not more than about 0.03 wt % N, with the contents of C and N satisfying the relations: about 0.005 wt %.ltoreq.(C+N)&lt;about 0.03 wt %, and (C/N)&lt;about 0.6. The sheet also includes Ti in an amount to satisfy the relation: about 5.ltoreq.Ti/(C+N).ltoreq.about 30. The balance of the sheet includes Fe and incidental impurities, with the sheet having an X-ray integral intensity ratio (222)/(310) of not less than about 35 in a plane parallel to a sheet surface at a depth of 1/4 of the sheet thickness from the sheet surface. This ferritic stainless steel sheet may be produced by a method which includes hot rolling said steel having the above-described composition at a final pass reduction ratio during rough rolling of not less than about 40% and at a final finish rolling temperature of not more than about 750.degree. C. The hot rolled sheet is subsequently annealed, cold rolled, and finish annealed.

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Chiba, Japan

Yoshihiro Yazawa