Nippon Steel Corporation

Siltronic Ag

Nippon Steel Sumitomo Metal Corporation

Seiki Takebayashi

Yoshiyuki Ushigami

Hiroyasu Fujii

Shuichi Nakamura

Shinsuke Takatani

Teruyuki Tamaki

Yutaka Kishida

Wataru Ohashi

Takashi Kataoka

Fumiaki Takahashi

Shuichi Yamazaki

Kenichi Murakami

Yoshiaki Natori

Shunsuke Okumura

Mitsuru Morita

Yuji Kubo

Koki Tanaka

Keiichi Kimura

Nobusato Morishige

Masamoto Tanaka

Kazumi Mizukami

Shingo Okada

Hotaka Honma

Hideo Kato

Kiyoshi Sawano

Katsuyoshi Miyamoto

Masahiro Tanaka

This grain-oriented electrical steel sheet includes a steel sheet, an insulation coating disposed on the steel sheet, and a spinel present at a part on the steel sheet at an interface between the steel sheet and the insulation coating by being fitted into the insulation coating, in which an amount of the spinel is 5 to 50 mg/mper unit area of a surface of the steel sheet.

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

This manufacturing method of a grain-oriented electrical steel sheet is a manufacturing method of a grain-oriented electrical steel sheet having no forsterite film, in which in a decarburization annealing process, a cold-rolled steel sheet is (i-1) heated at an average heating rate (HR1) of 40 to 500° C./sec in a temperature range of 550° C. or higher and lower than 720° C., (i-2) heated at an average heating rate (HR2), which is 5 to 50° C./sec, in a temperature range of 720° C. to T1° C. (770° C.≤T1 (° C.)≤900° C.), and (ii) retained at the temperature of T1° C. for 50 to 1000 seconds to make an amount of C 25 ppm or less in an atmosphere of an oxygen partial pressure (P1) which is 0.0010 to 0.20.

Manufacturing method of grain-oriented electrical steel sheet

In a base sheet for a grain-oriented electrical steel sheet of the present invention, an amount of surface oxygen x per one surface of the base sheet and a value y of a peak (ΔR/R@1250 cm) of SiOon the surface of the base sheet obtained by infrared reflection spectroscopy satisfy y≥1500xand y≥0.24. A method of manufacturing the base sheet for a grain-oriented electrical steel sheet of the present invention includes: adjusting the amount of surface oxygen per one surface of a final-annealed grain-oriented silicon steel sheet to more than 0.01 g/mand 0.05 g/mor less, or more than 0.05 g/mand 0.10 g/mor less; and performing thermal oxidation annealing in an atmosphere in which an oxidation potential represented by a ratio P/Pof water vapor pressure to hydrogen pressure is 0.0081 or less in a case where the amount of surface oxygen is more than 0.01 g/mand 0.05 g/mor less, or in an atmosphere in which the oxidation potential is 0.005 or less in a case where the amount of surface oxygen is more than 0.05 g/mand 0.10 g/mor less, at a soaking temperature of 1000° C. or lower to form an externally oxidized layer on a surface of the grain-oriented silicon steel sheet.

Base sheet for grain-oriented electrical steel sheet, grain-oriented silicon steel sheet which is used as material of base sheet for grain-oriented electrical steel sheet, method of manufacturing base sheet for grain-oriented electrical steel sheet, and method of manufacturing grain-oriented electrical steel sheet

A grain-oriented electrical steel sheet includes: a base steel sheet; an intermediate layer arranged in contact with the base steel sheet; and an insulation coating arranged in contact with the intermediate layer to be an outermost surface, in which the intermediate layer has a local oxidized area when viewing a cross section whose cutting direction is parallel to a thickness direction, and a thickness of the intermediate layer in an area where the local oxidized area is included is 50 nm or more, and a thickness of the intermediate layer in an area where the local oxidized area is not included is less than 50 nm.

Grain-oriented electrical steel sheet

A grain-oriented electrical steel sheet includes: a base steel sheet; an intermediate layer arranged in contact with the base steel sheet; and an insulation coating arranged in contact with the intermediate layer to be an outermost surface, in which the insulation coating has a crystalline phosphide-containing layer containing a crystalline phosphide in an area in contact with the intermediate layer when viewing a cross section whose cutting direction is parallel to a thickness direction.

A grain-oriented electrical steel sheet according to an aspect of the present invention includes: a steel sheet; an intermediate layercontaining Si and O, arranged on the steel sheet; and an insulation coatingarranged on the intermediate layer, in which the intermediate layercontains a metal phosphide, a thickness of the intermediate layeris 4 nm or more, and an abundance of the metal phosphidepresent is 1% to 30% by cross-sectional area fraction in a cross section of the intermediate layer

Grain-oriented electrical steel sheet and method of manufacturing grain-oriented electrical steel sheet

Nitriding process of a steel strip is performed. Next, annealing is performed to form a forsterite based glass coating film at a surface of the steel strip. Heating is performed up to 1000&#xb0; C. or more in a mixed gas atmosphere containing Hgas and Ngas, and a rate of Ngas is 20 volume % or more, next, the atmosphere is switched into Hgas atmosphere at the temperature of 1000&#xb0; C. or more and 1100&#xb0; C. or less, when the annealing is performed. An oxygen potential P (HO)/P (H) is set to be 0.05 to 0.3 when the temperature is 850&#xb0; C. or less during the heating in the mixed gas atmosphere.

Grain-oriented electrical steel sheet and manufacturing method thereof

In silicon single crystal growth by the Czochralski method using a quartz crucible, a silicon single crystals with a uniform distribution of oxygen concentration can be produced in high yield without being affected by changes of crystal diameter and initial amount of melt feedstock. The oxygen concentration is adjusted by estimating oxygen concentration during growth on the basis of a relationship among three parameters: crucible rotation rate (&#x3a9;), crucible temperature (T), and the ratio (&#x3b2;) of contact area of molten silicon with the inner wall of the crucible and with atmospheric gas, and by associating the temperature (T) with the ratio (&#x3b2;) by the function 1/&#x3b2;&#xd7;Exp(&#x2212;E/T) where E is the dissolution energy (E) of quartz into molten silicon to control at least one of the rotation rate (&#x3a9;) and temperature (T) to conform the estimated oxygen concentration to a target concentration.

Silicone single crystal production process

A single crystal production method based on the Czochralski method comprises controlling a number of crucible rotations and crystal rotations so that a number of vibrations for driving a melt, determined on the basis of the number of crucible and crystal rotations during a single crystal growing procedure, is outside a range from 95% to 105% of a number of sloshing resonance vibrations of the melt. In another embodiment, the method comprises controlling a number of rotations of a crystal and crucible, so that when a number of vibrations for driving a melt, determined by the number of crucible and crystal rotations during a single crystal growing procedure, is within a range from 95% to 105% of a number of sloshing resonance vibrations of the melt, the number of vibrations of the melt due to sloshing does not exceed 2000 times during a period when the number of vibrations is within that range.

Single crystal production method

In the manufacture of a silicon single crystal by the Czochralski method, there is provided a seed crystal for use in the production of the silicon single crystal. This seed crystal is capable of preventing creation of a dislocation occurring during the immersion of the seed crystal in the molten silicon and withstanding the load of a silicon single crystal of great weight as well. There is also a method for the production of the seed crystal and a method for the production of a silicon single crystal which enables the ratio of elimination of dislocation to be increased. A seed crystal for the production of a silicon single crystal for use in the manufacture of a silicon single crystal by the Czochralski method, has the boron concentration in the silicon single crystal as the matrix from which the silicon seed crystal is excised is not less than 4&times;10 atoms/cm and not more than 4&times;10 atoms/cm and the silicon seed crystal is excised from the silicon single crystal as the matrix, ground, and lapped, and subsequently subjected to surface etching.

Seed crystal for production of silicon single crystal and method for production of silicon single crystal

In the growth of a large silicon single crystal weighing not less than 100 kg by the Czokralski method resorting to application of a magnetic field, a crucible, not less than 0.7 m in inside diameter is used, and a cusped magnetic field which manifests a maximum intensity of not more than 1000 gausses on the inner wall of the crucible is applied.

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Tokyo, Japan

Seiki Takebayashi