Jfe Steel Corporation

Kawasaki Steel Corporation

Tadashi Nakanishi

Yoshihiko Oda

Hiroaki Toda

Tomoyuki Okubo

Yoshiaki Zaizen

Hiroaki Nakajima

Shinji Koseki

Seiji Okabe

Toshito Takamiya

Kunihiro Senda

Hiroi Yamaguchi

Takeshi Omura

Minoru Takashima

Mitsumasa Kurosawa

Masanori Uesaka

Yukihiro Shingaki

Tatsuhiko Hiratani

Seiji Nabeshima

Takeshi Murai

Masaaki Kohno

A steel containing C: not more than 0.0050%, Si: 0.1-5.0%, Mn: 0.02-3.0%, sol. Al: not more than 0.0050%, P: not more than 0.2%, S: not more than 0.0050%, N: not more than 0.0040%, T. Ca: 0.0010-0.0080%, T. O: not more than 0.0100% and having (T. Ca/T. O) of not less than 0.50 but not more than 2.0 by decarburizing to a C content of not more than 0.0050%, adding Si, decreasing Al as much as possible, and adding Ca is melted to form a slab. The slab is subjected to a hot rolling at a coiling temperature of not lower than 550&#xb0; C., a cold rolling and a finish annealing, or the slab is subjected to a hot rolling, a hot band annealing at a temperature of 900-1150&#xb0; C., a cold rolling and a finish annealing to thereby produce a non-oriented electrical steel sheet.

Non-oriented electrical steel sheet and production method thereof

Methods for producing non-oriented electrical steel sheets comprising steps including hot rolling a slab having a chemical composition comprising C: not more than 0.01 mass %, Si: not more than 6 mass %, Mn: 0.05-3 mass %, P: not more than 0.2 mass %, Al: not more than 2 mass %, N: not more than 0.005 mass %, S: not more than 0.01 mass %, Ga: not more than 0.0005 mass %, and the remainder being Fe and inevitable impurities, pickling without conducting hot band annealing or after conducting hot band annealing or self-annealing, subjecting to one or more cold rollings including an intermediate annealing therebetween and a finish annealing, and forming an insulation coating, an average heating rate from 500 to 800&#xb0; C. in the heating process of the finish annealing is not less than 50&#xb0; C./s, whereby a non-oriented electrical steel sheet having excellent magnetic properties is obtained even if hot band annealing is omitted.

Method for producing non-oriented electrical steel sheet having excellent magnetic properties

In the production of a non-oriented electrical stress sheet by hot rolling a slab having a chemical composition comprising, by mass %, C: not more than 0.005, Si: 1.5-6.0, Mn: 0.05-2.0 and P: 0.03-0.15, subjecting to a hot band annealing, if necessary, cold rolling, finish annealing, and forming an insulation coating, the cooling from 700&#xb0; C. to 500&#xb0; C. in the finish annealing is conducted in an oxidizing atmosphere with an oxygen potential P/Pof not less than 0.001 for 1-300 seconds, whereby P is segregated into the surface of the steel sheet after the finish annealing to obtain a non-oriented electrical steel sheet enhancing a crystal grain growth properties in the stress relief annealing.

Non-oriented electrical steel sheet, production method therefor, and motor core

When a non-oriented electrical steel sheet is produced by hot rolling a slab containing, by mass %, C: not more than 0.0050%, Si: 1.5-5.0%, Mn: 0.20-3.0%, sol. Al: not more than 0.0050%, P: not more than 0.2%, S: not more than 0.0050% and N: not more than 0.0040% to form a hot rolled sheet, cold rolling the hot rolled sheet without conducting a hot band annealing and then subjecting to a finish annealing, a compositional ratio of CaO in oxide-based inclusions existing in the slab defined by CaO/(SiO+AlO+CaO) is set to not less than 0.4 and/or a compositional ratio of AlOdefined by AlO/(SiO+AlO+CaO) is set to not less than 0.3, and a coiling temperature in the hot rolling is set to not lower than 650&#xb0; C.

Non-oriented electrical steel sheet and method for producing the same

Disclosed is a non-oriented electrical steel sheet that is low in iron loss and exhibits excellent magnetic properties even when subjected to final annealing at high temperature. The non-oriented electrical steel sheet can be obtained from a steel (low-Al steel) having a chemical composition containing, in mass %, C: 0.005% or less, Si: 1.0% to 4.5%, Mn: 0.02% to 2.0%, Sol. Al: 0.001% or less, P: 0.2% or less, S+Se: 0.0010% or less, N: 0.005% or less, O: 0.005% or less, and Cu: 0.02% to 0.30%, and the balance consisting of Fe and incidental impurities.

Non-oriented electrical steel sheet and method for manufacturing non-oriented electrical steel sheet

A non-oriented electrical steel sheet having a chemical composition comprising C: not more than 0.010 mass %, Si: 1.0-7.0 mass %, Mn: 0.001-3.0 mass %, sol. Al: 0.0001-3.5 mass %, P: 0.01-0.2 mass %, S: not more than 0.010 mass %, N: not more than 0.010 mass % and the remainder being Fe and inevitable impurities, wherein a ratio (P/Fe) of a peak-peak height Pof P near to an electronic energy of 120 eV to a peak-peak height Feof Fe near to an electronic energy of 700 eV in an Auger differential spectrum obtained by analyzing a broken surface of a grain boundary through Auger electron spectroscopy is not less than 0.1 and a sheet thickness is 0.10-0.50 mm, and a motor using such a non-oriented electrical steel sheet as an iron core.

Non-oriented electrical steel sheet having high magnetic flux density and motor

A non-oriented electrical steel sheet is obtained by subjecting a slab containing C: not more than 0.005 mass %, Si: 1.0-5.0 mass %, Mn: 0.04-3.0 mass %, sol. Al: not more than 0.005 mass %, P: 0.03-0.2 mass %, S: not more than 0.005 mass %, N: not more than 0.005 mass %, B: not more than 0.001 mass %, and Se: not more than 0.001 mass % and satisfying sol. Al+C+5B+5Se&#x2264;0.005 mass % to hot rolling, cold rolling and finish annealing. A sheet temperature at the outlet side of the rolling machine in at least one pass of the final cold rolling is set to a range of 100-300&#xb0; C. to provide S/2M of not less than 1.0 and S/5C of not less than 1.0 when X-ray intensity ratios of {001}&#x3c;250&#x3e;, {111}&#x3c;112&#x3e; and {001}&#x3c;100&#x3e; in a central layer in a thickness direction are S, M and C, respectively.

Non-oriented electrical steel sheet and method for producing the same, and motor core and method of producing the same

According to the present invention, a high-strength electrical steel sheet that is suitable as rotor material for a high speed motor, steadily has high strength, and also has excellent magnetic properties can be obtained by setting the chemical composition thereof to include, by mass %, C: 0.005% or less, Si: more than 3.5% and 4.5% or less, Mn: 0.01% or more and 0.10% or less, Al: 0.005% or less, Ca: 0.0010% or more and 0.0050% or less, S: 0.0030% or less, and N: 0.0030% or less, Ca/S being 0.80 or more, the balance being Fe and incidental impurities, and by setting the sheet thickness to 0.40 mm or less, the non-recrystallized deformed microstructure to 10% or more and 70% or less, tensile strength (TS) to 600 MPa or more, and iron loss Wto 30 W/kg or less.

High-strength electrical steel sheet and method of producing the same

A non-oriented electrical steel sheet having a high magnetic flux density and a low anisotropy contains C: not more than 0.01 mass %, Si: 1-4 mass %, Mn: 0.05-3 mass %, P: 0.03-0.2 mass %, S: not more than 0.01 mass %, Al: not more than 0.004 mass %, N: not more than 0.005 mass %, As: not more than 0.003 mass %, and preferably further contains one or two of Sb: 0.001-0.1 mass % and Sn: 0.001-0.1 mass % or further contains one or two of Ca: 0.001-0.005 mass % and Mg: 0.001-0.005 mass %.

Non-oriented electrical steel sheet having excellent magnetic properties

By using a hot-rolled steel sheet of a predetermined chemical composition, and annealing the hot-rolled steel sheet in nitrogen atmosphere at 1000&#xb0; C. for 30 seconds, and then immersing in a solution of 7% HCl at 80&#xb0; C. for 60 seconds to obtain a hot-rolled steel sheet having a pickling weight loss of 10 g/mor more and 35 g/mor less, it is possible to obtain a hot-rolled steel sheet for producing a non-oriented electrical steel sheet that not only has excellent magnetic properties such as iron loss properties and magnetic flux density, but also has reduced steel sheet surface defects and an excellent manufacturing yield.

Hot-rolled steel sheet for producing non-oriented electrical steel sheet and method of producing same

A non-oriented electrical steel sheet having a high magnetic flux density and a low iron loss at not only a commercial frequency but also a high frequency zone, which has a chemical composition including C: not more than 0.0050 mass %, Si: more than 1.5 mass % but not more than 5.0 mass %, Mn: not more than 0.10 mass %, sol. Al: not more than 0.0050 mass, P: more than 0.040 mass % but not more than 0.2 mass %, S: not more than 0.0050 mass %, N: not more than 0.0040 mass % and Ca: 0.001-0.01 mass % and the remainder being Fe and inevitable impurities and a compositional ratio of CaO in oxide-based inclusions existing in a steel sheet of not less than 0.4 and/or a compositional ratio of AlOof not less than 0.3, and a hot rolled steel sheet used as a raw steel material thereof.

Non-oriented electrical steel sheet and hot rolled steel sheet thereof

The pickling loss when a hot-rolled steel sheet having a predetermined chemical composition is annealed at 1000&#xb0; C. for 30 seconds in a nitrogen atmosphere and then immersed in a solution of 7% HCl at 80&#xb0; C. for 60 seconds is in a range of 40 g/mor more and 100 g/mor less. A hot-rolled steel sheet for production of a non-oriented electrical steel sheet with not only excellent magnetic properties such as iron loss and magnetic flux density but also excellent recyclability and steel sheet surface appearance can thus be obtained.

Hot-rolled steel sheet for production of non-oriented electrical steel sheet and method of manufacturing same

A non-oriented electrical steel sheet having a high magnetic flux density and a low iron loss is produced by hot rolling a steel slab comprising C: not more than 0.005 mass %, Si: not more than 4 mass %, Mn: 0.03-3 mass %, Al: not more than 3 mass %, P: 0.03-0.2 mass %, S: present at not more than 0.005 mass %, N: not more than 0.005 mass %, Ca: 0.0005-0.01 mass %, provided that an atom ratio of Ca to S ((Ca mass %/40)/(S mass %/32)) is within a range of 0.5-3.5, and the balance being Fe and incidental impurities, hot band annealing, cold rolling, and then conducting recrystallization annealing by heating at an average temperature rising rate of not less than 100&#xb0; C/s up to at least 740&#xb0; C.

Method of producing non-oriented electrical steel sheet

A grain oriented electrical steel sheet has a magnetic domain structure modified by strain introduction without a trace of treatment, in which noise generated when the grain oriented electrical steel sheet is used laminated on an iron core of a transformer is effectively reduced by: setting a magnetic flux density Bto 1.92 T or higher; then setting a ratio of average magnetic domain width of treated surface after strain-introducing treatment Wto average magnetic domain width before strain-introducing treatment Was W/W&#x3c;0.4; and setting a ratio of Wto average magnetic domain width of untreated surface Was W/W&#x3e;0.7; and further setting a ratio of average width of magnetic domain discontinuous portion Win the untreated surface to average width of magnetic domain discontinuous portion in treated surface resulting from strain-introducing treatment Was W/W&#x3e;0.8; and setting W&#x3c;0.35 mm.

Grain oriented electrical steel sheet

A method produces a high strength electrical steel sheet in which a cumulative rolling reduction ratio in rough rolling is 73.0% or more, in which in a hot band annealing step, an annealing condition is selected that satisfies an area ratio of recrystallized grains after hot band annealing of 100%, and a recrystallized grain size of 80 &#x3bc;m to 300 &#x3bc;m, under a condition where annealing temperature is 850&#xb0; C. to 1000&#xb0; C., and annealing duration is 10 seconds to 10 minutes, and in which in a final annealing step, an annealing condition is selected that satisfies an area ratio of recrystallized grains after the final annealing of 30% to 95%, and a length in the rolling direction of a connected non-recrystallized grain group of 2.5 mm or less, under a condition where annealing temperature is 670&#xb0; C. to 800&#xb0; C., and annealing duration is 2 seconds to 1 minute.

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Tokyo, Japan

Tadashi Nakanishi