Jfe Steel Corporation

Sony Corporation

Masanori Takenaka

Takeshi Imamura

Yasuyuki Hayakawa

Yuiko Ehashi

Minoru Takashima

Makoto Watanabe

Toshito Takamiya

Hiroi Yamaguchi

Yukihiro Shingaki

Hiroshi Matsuda

Takashi Terashima

Takeshi Omura

Soshi Yoshimoto

Hirokazu Sugihara

Hiroshi Kawai

Yuiko Wakisaka

Provided is a method for manufacturing a grain-oriented electrical steel sheet. A steel slab having a specific chemical composition is heated and hot rolled. A hot-rolled steel sheet thus obtained is subjected to hot band annealing to obtain a cold-rolled steel sheet, which is then subjected to primary recrystallization annealing to obtain a primary recrystallized steel sheet. An annealing separator is applied to the primary recrystallized steel sheet, which is then coiled. The coil is subjected to secondary recrystallization annealing to obtain a grain-oriented electrical steel sheet having an average value of a deviation angle (α+β)calculated from a deviation angle α from ideal Goss orientation around an ND rotation axis and a deviation angle β from ideal Goss orientation around a TD rotation axis of 4.5° or less, and an area ratio Rof crystal grains with β≤0.50° of 15% or less.

Method for manufacturing a grain-oriented electrical steel sheet

A grain oriented electrical steel sheet is produced by heating a steel slab containing, by mass %, C:0.02-0.10%, Si:2.0-5.0%, Mn:0.01-1.00%, sol. Al:0.01-0.04%, N:0.004-0.020% and S+Se:0.002-0.040% to a temperature of higher than 1280° C., and subjecting the sheet to a hot rolling, a hot-band annealing, a single cold rolling or two or more cold rollings having an intermediate annealing between each cold rolling and a primary recrystallization annealing combined with a decarburization annealing, applying an annealing separator onto a steel sheet surface, and subjecting the sheet to a finish annealing and a flattening annealing, a rapid cooling is conducted at an average cooling rate of not less than 200° C./s from 800° C. to 300° C. in the cooling process from a maximum achieving temperature in at least one annealing of the hot-band annealing and the intermediate annealing.

Method for producing grain-oriented electrical steel sheet

Provided is a grain-oriented electrical steel sheet having a film that is effective for the magnetic properties of the steel sheet and particularly effective for iron loss reduction and has favorable adhesion. In a grain-oriented electrical steel sheet, an insulating film partially enters into a steel substrate to form an anchor part, a depth of the anchor part from the surface of the steel substrate is 3.5 μm or less, and a number of neck parts of 5 μmor less in area is 0.06/μmor less and a number of neck parts of 10 μmto 40 μmin area is 0.005/μmor more and 0.011/μmor less, where each neck part is a remaining part of the insulating film on the surface of the steel substrate when peeling the insulating film from the steel substrate in a bend test for the grain-oriented electrical steel sheet.

Grain-oriented electrical steel sheet and production method therefor

With a hot-rolled steel sheet for electrical steel sheet production having a scale layer on the surface, where the surface of the steel sheet has a lightness L* as defined in JIS Z 8781-4: 2013 satisfying 30&#x2264;L*&#x2264;50, and chromaticities a* and b* as defined in JIS Z 8781-4: 2013 satisfying &#x2212;1&#x2264;a*&#x2264;2 and &#x2212;5&#x2264;b*&#x2264;3 respectively, and with one end portion in the longitudinal direction of a coil as a reference, a color difference &#x394;E* as defined in JIS Z 8781-4: 2013 at the central portion and at the opposite end portion satisfies &#x394;E*&#x2264;8, it is possible to obtain a grain-oriented electrical steel sheet where the variation of properties in a product coil is small.

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

Provided is a grain-oriented electrical steel sheet that has excellent magnetic properties and can be manufactured by secondary recrystallization orientation control using coil annealing with high productivity. A grain-oriented electrical steel sheet comprises a specific chemical composition, wherein an average value of a deviation angle (&#x3b1;+&#x3b2;)calculated from a deviation angle &#x3b1; from ideal Goss orientation around an ND rotation axis and a deviation angle &#x3b2; from ideal Goss orientation around a TD rotation axis is 5.0&#xb0; or less, and an area ratio Rof crystal grains with &#x3b2;&#x2264;0.50&#xb0; is 20% or less.

Grain-oriented electrical steel sheet and method for manufacturing same

In a production of a grain-oriented electrical steel sheet by subjecting a steel slab containing a particular composition and further including an inhibitor-forming ingredient to hot rolling, hot-band annealing, cold rolling, primary recrystallization annealing combined with decarburization annealing and finish annealing, the steel slab satisfies a given relation between a content ratio of sol. Al to N and a final sheet thickness, and, in the finish annealing, the steel sheet is kept at a temperature zone of higher than 850&#xb0; C. but not higher than 950&#xb0; C. in heating process for 5 to 200 hours, heated to a temperature zone of 950 to 1050&#xb0; C. at 5 to 30&#xb0; C./hr and further subjected to purification treatment of keeping a temperature of not lower than 1100&#xb0; C. for not less than 2 hours to provide a secondary recrystallization structure that has an average value of a diameter equivalent to a circle of 10 to 100 mm.

Low-iron-loss grain-oriented electrical steel sheet and production method for same

To improve and stabilize magnetic properties, a steel sheet is soaked in a temperature range of 1000&#xb0; C. or more and 1120&#xb0; C. or less for 200 sec or less and then soaked in a temperature range of 650&#xb0; C. or more and 1000&#xb0; C. or less for 200 sec or less in annealing before final cold rolling, and the amount of Al in precipitates after the annealing before the final cold rolling is limited to 50% or more of the total amount of Al contained in the steel slab.

Method of producing grain-oriented electrical steel sheet

To provide a grain-oriented electrical steel sheet that has better magnetic property than conventional ones without requiring high-temperature slab heating, in the case of not performing intermediate annealing, the hot rolled steel sheet obtained by a predetermined step is subjected to hot band annealing, and, in a heating process in the hot band annealing, heating is performed at a heating rate of 10&#xb0; C./s or less for 10 sec or more and 120 sec or less in a temperature range of 700&#xb0; C. or more and 950&#xb0; C. or less, and in the case of performing the intermediate annealing, in a heating process in final intermediate annealing, heating is performed at a heating rate of 10&#xb0; C./s or less for 10 sec or more and 120 sec or less in a temperature range of 700&#xb0; C. or more and 950&#xb0; C. or less.

In a grain-oriented electrical steel sheet which is manufactured from a thin slab without using an inhibitor forming component, excellent magnetic properties are stably achieved. In a method for manufacturing a grain-oriented electrical steel sheet, a slab heating and annealing are performed under specific conditions.

Method for manufacturing grain-oriented electrical steel sheet

In the production of a grain-oriented electrical steel sheet by hot rolling a slab containing Si: 2.0-8.0 mass % and no inhibitor-forming ingredients, cold rolling, subjecting to a decarburization annealing, applying an annealing separator composed mainly of MgO and containing a Ti compound(s) and subjecting to a finish annealing, an atmosphere in the heating process of the decarburization annealing is rendered into a dry atmosphere having a dew point of not higher than 0&#xb0; C. and a Ti amount (Ti(a)) and a N amount (N(a)) contained in an iron matrix after the removal of a forsterite coating and a Ti amount (Ti(b)) and a N amount (N(b)) contained in the steel sheet having a forsterite coating are made to satisfy relationships as N(b)&#x2264;0.0050 mass %, N(b)/N(a)&#x2265;4, and Ti(b)/Ti(a)&#x2265;4.

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

Provided are a grain-oriented electrical steel sheet with low iron loss even when including at least one grain boundary segregation element among Sb, Sn, Mo, Cu, and P, and a method for manufacturing the same. In our method, Pr is controlled to satisfy Pr&#x2264;&#x2212;0.075T+18, where T&#x3e;10, 5&#x3c;Pr, T (hr) is the time required after final annealing to reduce the temperature of a secondary recrystallized sheet from 800&#xb0; C. to 400&#xb0; C., and Pr (MPa) is the line tension on the secondary recrystallized sheet during flattening annealing. As a result, a grain-oriented electrical steel sheet in which iron loss is low and a dislocation density near crystal grain boundaries of the steel substrate is 1.0&#xd7;10mor less can be obtained even when the grain-oriented electrical steel sheet contains at least one of Sb, Sn, Mo, Cu, and P.

The disclosure contains, in mass % or mass ppm: C: 0.005% or less, Si: 2.0% to 5.0%, Mn: 0.01% to 0.5%, sol.Al: 10 ppm or less, N: 15 ppm or less, S and Se: each 10 ppm or less, and three or more selected from Sn, Sb, Cr, P, Mo and B whose contents satisfy a relational expression of 0.16&#x2264;[% Sn]+[% Sb]+[% Cr]+2&#xd7;[% P]+[% Mo]+[% B]&#x2264;0.50, the balance being Fe and inevitable impurities, where a number of times of repeated bending in a bend test is 10 or more.

Grain-oriented electrical steel sheet and method for manufacturing the same

Provides is a method of producing a grain oriented electrical steel sheet by heating a steel slab having a predetermined composition, then subjecting the slab to hot rolling to obtain a hot rolled sheet, then optionally subjecting the hot rolled sheet to hot band annealing and subsequent cold rolling once, or twice or more with intermediate annealing performed therebetween to obtain a cold rolled sheet with final sheet thickness, then subjecting the cold rolled sheet to primary recrystallization annealing and subsequent secondary recrystallization annealing, in which the aging index AI of the steel sheet before final cold rolling is set to 70 MPa or less to effectively grow Goss-oriented grains to thereby obtain a grain-oriented electrical steel sheet with good magnetic properties, without the restriction of containing a relatively large amount of C.

Method of producing grain oriented electrical steel sheet

A method of manufacturing a grain oriented electrical steel sheet uses austenite (&#x3b3;)-ferrite (&#x3b1;) transformation which develops excellent magnetic properties, uses Tcalculated from equation (1) and performs the first pass of rough hot rolling at a temperature of (T&#x2212;100)&#xb0; C. or higher with a rolling reduction of 30% or more, and further uses Tcalculated from equation (2) and performs any one pass of finish hot rolling in a temperature range of (T&#xb1;50)&#xb0; C. with a rolling reduction of 40% or more:[&#xb0; C.]=1383.98&#x2212;73.29[% Si]+2426.33[% C]+271.68[% Ni]&#x2003;&#x2003;(1)[&#xb0; C.]=1276.47&#x2212;59.24[% Si]+919.22[% C]+149.03[% Ni]&#x2003;&#x2003;(2)where [% A] represents content of element 'A' in steel (mass %).

Method of manufacturing grain oriented electrical steel sheet

A grain oriented electrical steel sheet has sufficiently low iron loss and having less conventionally-concerned warpage of the steel sheet even after the steel sheet is subjected to artificial magnetic domain refining treatment, where strain-introducing treatment is conducted with high energy so that an iron loss-reducing effect can be maximized. The grain oriented electrical steel sheet is obtained by adjusting tension to be applied to a tension-applying insulating coating, or to both surfaces of the steel sheet by the tension-applying insulating coating, before strain-introducing treatment in the range of Formula (1):1.0&#x2266;(tension applied to non-strain-introduced surface)/(tension applied to strain-introduced surface)&#x2266;2.0&#x2003;&#x2003;(1),and by controlling the amount of warpage of the steel sheet toward the strain-introduced surface side after strain-introducing treatment in the range of 1 mm or more and 10 mm or less.

Growing community of inventors

Tokyo, Japan

Masanori Takenaka