Nippon Steel & Sumikin Stainless Steel Corporation

Nippon Steel Corporation

Nippon Steel Stainless Steel Corporation

Shinichi Teraoka

Ken Kimura

Shunji Sakamoto

Toshiyuki Suehiro

Yoshiharu Inoue

Eiichiro Ishimaru

Akihiko Takahashi

Masanori Ueda

Masaaki Kobayashi

Junichi Hamada

Masaharu Hatano

Akihiro Nishimura

Norihiro Kanno

Toshio Tanoue

Shinichi Tamura

Masuhiro Fukaya

Shuichi Inoue

Yuuji Koyama

Jun Takahashi

Shigeyuki Gotoh

Takashi Arai

Masayuki Abe

Hideki Fujii

Nobuhiko Hiraide

Hideki Oka

Hidehiko Sumitomo

Kazuhiko Adachi

Akihiro Fukuda

Yuji Koyama

Tetsurou Takeshita

Shigeru Minamino

Shunji Shoda

Yoshikatsu Nohara

Takuji Shindo

Yoshimori Fukuda

Takehisa Mizunuma

Hiroshi Urashima

Atsuhisa Yakawa

Takanori Nakazawa

Yuichi Satoh

Eiichirou Ishimaru

An austenitic stainless steel according to the present invention has a chemical composition containing, by mass %: C: 0.01 to 0.15%; Si: 2.0% or less; Mn: 3.0% or less; Cr: 10.0 to 20.0%; Ni: 5.0 to 13.0%; N: 0.01 to 0.30%; Nb: 0 to 0.5%; Ti: 0 to 0.5%; and V: 0 to 0.5%, with the balance: Fe and impurities, wherein an average grain size is 10.0 &#x3bc;m or less, a difference in value of an average lattice constant d(={d&#xd7;I+d&#xd7;I+d&#xd7;I+d&#xd7;I}/{I+I+I+I}) of an austenite phase between a surface portion and a center portion is 0.010 &#x212b; or more, and a value of a diffraction peak integrated intensity ratio r (=100&#xd7;&#x3a3;I/&#x3a3;I) at a surface is 95% or more.

Austenitic stainless steel

A ferritic stainless steel plate having a sheet thickness t of 5.0 to 12.0 mm, including a chemical composition consisting of, in mass percent, C: 0.001 to 0.010%, Si: 0.01 to 1.0%, Mn: 0.01 to 1.0%, P: 0.04% or less, S: 0.010% or less, Cr: 10.0 to 20.0%, Ni: 0.01 to 1.0%, Ti: 0.10 to 0.30%, V: 0.01 to 0.40%, Al: 0.005 to 0.3%, N: 0.001 to 0.02%, and as necessary, one or more of B, Mo, Cu, Mg, Sn, Sb, Zr, Ta, Nb, Hf, W, Co, Ca, REM, and Ga, with the balance being Fe and unavoidable impurities, wherein in a steel micro-structure, on a cross section parallel to a rolling direction, an area ratio of structures each satisfying: major grain diameter/minor grain diameter being 5.0 or more is 90% or more, and an average minor grain diameter of the structures is 100 &#x3bc;m or less.

Ferritic stainless steel sheet, hot coil, and automobile exhaust flange member

A ferritic stainless steel plate having a sheet thickness t of 5.0 to 12.0 mm, including a chemical composition consisting of, in mass percent, C: 0.001 to 0.010%, Si: 0.01 to 1.0%, Mn: 0.01 to 1.0%, P: 0.04% or less, S: 0.010% or less, Cr: 10.0 to 20.0%, Ni: 0.01 to 1.0%, Ti: 0.10 to 0.30%, V: 0.01 to 0.40%, Al: 0.005 to 0.3%, N: 0.001 to 0.02%, and as necessary, one or more of B, Mo, Cu, Mg, Sn, Sb, Zr, Ta, Nb, Hf, W, Co, Ca, REM, and Ga, with the balance being Fe and unavoidable impurities, wherein in a steel micro-structure, on a cross section parallel to a rolling direction, an area ratio of structures each satisfying: major grain diameter/minor grain diameter being less than 5.0 is 90% or more, and an average minor grain diameter of the structures is 55 &#x3bc;m or less. The ferritic stainless steel sheet is excellent in toughness and suitable for an automobile exhaust flange member and the like.

A Cr-containing ferritic stainless steel sheet is desired with improved corrosion resistance and rust resistance as well as improved ridging resistance. To achieve these results, the ferritic stainless steel sheet derives the relationship between Ap, which shows the &#x3b3;-phase rate at 1100&#xb0; C. due to a predetermined ingredient, and Sn in ferritic stainless steel which becomes a dual phase structure of &#x3b1;+&#x3b3; in the hot rolling temperature region, applies and adds Sn, and hot rolls the steel to give a total rolling rate of 15% or more in 1100&#xb0; C. or higher hot rolling to thereby obtain ferritic stainless steel sheet which has good ridging resistance, which also has excellent corrosion resistance and rust resistance, and which can be applied to general durable consumer goods, wherein 0.060&#x2264;Sn&#x2264;0.634&#x2212;0.0082Ap and 10&#x2264;Ap&#x2264;70.

Ferritic stainless steel plate which has excellent ridging resistance and method of production of same

This hot-rolled ferritic stainless steel sheet has a steel composition containing, in terms of % by mass: 0.02% or less of C; 0.02% or less of N; 0.1% to 1.5% of Si; 1.5% or less of Mn; 0.035% or less of P; 0.010% or less of S; 1.5% or less of Ni; 10% to 20% of Cr; 1.0% to 3.0% of Cu; 0.08% to 0.30% of Ti; and 0.3% or less of Al, with the balance being Fe and unavoidable impurities, and the hot-rolled ferritic stainless steel sheet has a Vickers hardness of less than 235 Hv.

Hot rolled ferritic stainless steel sheet, method for producing same, and method for producing ferritic stainless steel sheet

An automotive member or a feed oil pipe includes: a member made of a ferritic stainless steel containing predetermined components containing 10.5% to 18.0% of Cr in mass %; a metal fitting made of an aluminized stainless steel sheet, the metal fitting being attached to the member; and a gap structure defined between the member and the metal fitting, the gap structure being exposed to a chloride environment, where the metal fitting has an Al-plating weight per unit area of 20 g/mor more and 150 g/mor less on a surface corresponding to a gap of the gap structure, and surfaces of the metal fitting and the non-aluminized member other than the gap are coated with a cation electrodeposition coating film having a thickness of 5 &#x3bc;m to 35 &#x3bc;m.

Inexpensive automotive member and feed oil pipe, exhibiting excellent salt corrosion resistance

A ferritic stainless steel sheet having ridging resistance contains, by mass, 0.025 to 0.30% C, 0.01 to 1.00% Si, 0.01 to 2.00% Mn, 0.050% or less P, 0.020% or less S, 11.0 to 22.0% Cr, and 0.022 to 0.10% N. In addition, Ap, which is defined as 420C+470N+23Ni+9Cu+7Mn&#x2212;11.5(Cr+Si)&#x2212;12Mo&#x2212;52Al&#x2212;47Nb&#x2212;49Ti+189 wherein each of Sn, C, N, Ni, Cu, Mn, Cr, Si, Mo, Al, Nb, and Ti denotes the content of the element, satisfies 10&#x2266;Ap&#x2266;70. Furthermore, a content of Sn satisfies 0.060&#x2266;Sn&#x2266;0.634&#x2212;0.0082Ap. Residual ingredients are Fe and unavoidable impurities, and a metal structure of the steel sheet is a ferrite single phase. The ferritic stainless steel sheet has a ridging height of less than 6 &#x3bc;m. This ferritic stainless steel sheet improves the corrosion resistance and rust resistance of Cr-containing ferritic stainless steel as well as the ridging resistance.

The present invention is directed to a stainless steel brake disc which is excellent in toughness, corrosion resistance, and wear resistance, and comprises, in % by mass, 0.030 to 0.080% of C, 0.05% to 1.0% of Si, 1.0 to 1.5% of Mn, 0.035% or less of P, 0.015% or less of S, 11.0 to 14.0% of Cr, 0.01 to 0.50% of Ni, 0.001 to 0.15% of V, less than 0.1% of Nb, 0.05% or less of Ti, 0.05% or less of Zr, 0.05% or less of Al, 0.015 to 0.060% of N, 0.0002% or more and 0.0050% or less of B, and 0.0080% or less of O, wherein an AT value of equation 1 is 0.055 to 0.090, equation 2 is satisfied, a ferrite phase fraction, in which an IQ value of an EBSD pattern is 4,000 or more, is 1% to 15%, a Charpy impact value is 50 J/cmor more, and hardness is 32 to 38 HRC.C+0.8(N&#x2212;B)&#x2003;&#x2003;(1)PV=1.2Ti+0.8Zr+Nb+1.1Al+O&#x2266;0.1&#x2003;&#x2003;(2)

Stainless steel brake disc and method for production thereof

This ferritic stainless steel for components of an automobile exhaust system includes, in terms of percent by mass: C: &#x2266;0.015%; Si: 0.01% to 0.50%; Mn: 0.01% to 0.50%; P: &#x2266;0.050%; S: &#x2266;0.010%; N: &#x2266;0.015%; Al: 0.010% to 0.100%; Cr: 16.5% to 22.5%; Ni: 0.5% to 2.0%; and Sn: 0.01% to 0.50%, and further includes either one or both of Ti: 0.03% to 0.30% and Nb: 0.03% to 0.30%, with a remainder being Fe and inevitable impurities.

Ferrite-based stainless steel for use in components of automobile exhaust system

High strength dual-phase stainless steel sheet and steel strip which are excellent in corrosion resistance, the dual-phase stainless steel sheet and steel strip having a Vicker's hardness of 200HV or more and comprising, by mass %, C: 0.02 to 0.20%, Si: 0.10 to 2.0%, Mn: 0.20 to 2.0%, P: 0.040% or less, S: 0.010% or less, Cr: 15.0 to 18.0%, Ni: 0.5 to 4.0%, Sn: 0.05 to 0.50, N: 0.010 to 0.10%, and a balance of Fe and unavoidable impurities. The dual-phase stainless steel sheet and steel strip have a &#x3b3;p range of 60 to 95, and a ferrite and martensite dual-phase microstructure formed by being heated to the ferrite and austenite dual-phase region, then the austenite phase transforming to martenite in the subsequent cooling process, wherein &#x3b3;p=420C+470N+23Ni+7Mn+9Cu&#x2212;11.5Cr&#x2212;11.5Si&#x2212;12Mo&#x2212;7Sn&#x2212;49Ti&#x2212;47Nb&#x2212;52Al+189.

Dual-phase stainless steel sheet and steel strip and method of production

Ferritic stainless steel sheet for an exhaust part which has little deterioration in strength even if undergoing long term heat history and is low in cost, excellent in heat resistance and workability characterized by containing, characterized by containing, by mass %, C: less than 0.010%, N: 0.020% or less, Si: over 0.1% to 2.0%, Mn: 2.0% or less, Cr: 12.0 to 25.0%, Cu: over 0.9 to 2%, Ti: 0.05 to 0.3%, Nb: 0.001 to 0.1%, Al: 1.0% or less, and B: 0.0003 to 0.003%, having a Cu/(Ti+Nb) of 5 or more, and having a balance of Fe and unavoidable impurities.

Ferritic stainless steel sheet excellent in heat resistance and workability and method of production of same

The present invention provides an optimum low-chromium stainless steel which prevents corrosion resistance degradation of a weld in the case of welding a low-chromium stainless steel utilizing martensite transformation in multiple passes (multipass), is excellent in weld intergranular corrosion resistance even in a severe corrosion environment, simultaneously avoids occurrence of preferential corrosion at the bond-bordering region of the weld heat-affected zone, and is also excellent in productivity, which low-chromium stainless steel comprises, in mass %, C: 0.015 to 0.025%, N: 0.008 to 0.014%, Si: 0.2 to 1.0%, Mn: 1.0 to 1.5%, P: 0.04% or less, S: 0.03% or less, Cr: 10 to 13%, Ni 0.2 to 1.5%, and Al: 0.005 to 0.1% or less, and further comprises Ti: 6&#xd7;(C %+N %) or greater and 0.25% or less, the balance being Fe and unavoidable impurities, and the contents of the elements satisfy specified expressions.

Low-chromium stainless steel excellent in corrosion resistance of weld

The present invention provides optimal low chromium stainless steel preventing the deterioration in corrosion resistance at the weld zone in the case of multipass welding, superior in grain boundary corrosion resistance of the weld zone even in a harsh corrosive environment, simultaneously free from preferential corrosion at the heat affected zones near weld fusion lines, and further superior in manufacturability, that is, low chromium stainless steel containing, by mass %, C: 0.03% or less, N: 0.004 to 0.02%, Si: 0.2 to 1%, Mn: over 1.5 to 2.5%, P: 0.04% or less, S: 0.03% or less, Cr: 10 to 15%, Ni: 0.2 to 3.0%, and Al: 0.005 to 0.1%, further containing Ti: 4&#xd7;(C %+N %) to 0.35%, and having a balance of Fe and unavoidable impurities, having a &#x3b3;p(%) expressed by a predetermined formula satisfying 80 or more, and satisfying Ti %&#xd7;N %&#x3c;0.004 as well.

Low chromium stainless steel superior in corrosion resistance of multipass welded heat affected zones and its method of production

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Tokyo, Japan

Shinichi Teraoka