Nkk Corporation

Jfe Steel Corporation

Misao Namikawa

Yasushi Tanaka

Kenichi Arai

Tatsuhiko Hiratani

Kazushi Ishiyama

Shoji Kasai

Yoshikazu Takada

Hironori Ninomiya

Akira Hiura

Gou Kijima

Tsunehiro Yamaji

An elastic matrix determination method for a laminated iron core, which can optimally determine a shear modulus in two planes including a laminating direction of the laminated iron core included in an elastic matrix in a constitutive equation representing a stress-strain relationship used for vibration analysis, and also provided is a vibration analysis method. When performing a vibration analysis of a laminated iron core formed by laminating steel sheets using a constitutive equation representing a stress-strain relationship in a matrix representation, a shear modulus in two planes including a laminating direction of the laminated iron core included in an elastic matrix in the constitutive equation is determined depending on an average tightening pressure in the laminating direction of the laminated iron core.

Laminated iron core elastic matrix determination method and vibration analysis method

An elastic matrix determination method and a vibration analysis method for a laminated iron core, with which it is possible to optimally determine an elastic modulus of a laminated iron core. When a vibration analysis of a laminated iron core obtained by laminating steel sheets is performed by using a configuration expression indicating a relationship between stress and strain in a matrix display by using an elastic matrix, a shear modulus in two surfaces including a laminating direction of the laminated iron core included in the elastic matrix in the configuration expression is determined in consideration of slip between laminated steel sheets.

Elastic matrix determination method and vibration analysis method for laminated iron core

A silicon steel sheet having low iron loss of high frequency has a surface layer of the steel sheet which has Si concentration higher than Si concentration of a center portion of the steel sheet. Si concentration of sheet thickness center is 3.4 wt. % or more and Si concentration of the surface layer of the steel sheet is 5 wt. % or more. Si concentration in a surface layer portion is 5 to 8 wt. %. The production method comprises siliconizing treatment and diffusing treatment. Velocity of siliconizing and diffusing are controlled, and Si concentration distribution in the sheet thickness direction of the steel sheet is controlled.

Silicon steel sheet and method for producing the same

A soft magnetic alloy sheet has low residual magnetic flux density. The alloy sheet comprises a base element and an alloying element having a concentration gradient in a thickness direction of the alloy sheet. The alloying element is selected from Si, Al, Ni, Co and Fe.

Soft magnetic alloy sheet having low residual magnetic flux density

The present invention provides a method of manufacturing a silicon steel sheet having grains precisely arranged in the Goss orientation, comprising the steps of preparing a steel material containing 0.01 wt % or less of C, 2.5 to 7.0 wt % of Si, 0.01 wt % or less of S, 0.01 wt % or less of Al, 0.01 wt % or less of N, subjecting the steel material to hot rolling maintained 1000.degree. C. or higher such that the temperature of the rolled material at an end of the hot rolling step falls within the range of 700.degree. to 950.degree. C., subjecting the steel material to a primary cold rolling process at a rolling reduction of 30 to 85%, annealing the steel material at a temperature of 600.degree. to 900.degree. C., subjecting the steel material to a secondary cold rolling process at a rolling reduction of 40 to 80%, annealing the steel material again at a temperature of 600.degree. to 900.degree. C., subjecting the steel material to a tertiary cold rolling process at a rolling reduction of 50 to 75%, and annealing the steel material in a reducing atmosphere, or in a non-oxidizing atmosphere having an oxygen partial pressure of 0.5 Pa or less, or in a vacuum having an oxygen partial pressure of 0.5 Pa or less, at a temperature in the range of 1000.degree. to 1300.degree. C.

Method of manufacturing silicon steel sheet having grains precisely

The present invention provides a method of manufacturing a silicon steel sheet having grains precisely arranged in the Goss orientation, comprising the steps of preparing a steel material containing 0.01 wt. % or less of C, 2.5 to 7.0 wt. % of Si, 0.01 wt. % or less of S, 0.01 wt. % or less of Al, 0.01 wt. % or less of N, subjecting the steel material to hot rolling maintained 1000.degree. C. or higher such that the temperature of the rolled material at an end of the hot rolling step falls within the range of 700 to 950.degree. C., subjecting the steel material to a primary cold rolling process at a rolling reduction of 30 to 85%, annealing the steel material at a temperature of 600.degree. to 900.degree. C., subjecting the steel material to a secondary cold rolling process at a rolling reduction of 40 to 80%, annealing the steel material again at a temperature of 600.degree.to 900.degree. C., subjecting the steel material to a tertiary cold rolling process at a rolling reduction of 50 to 75%, and annealing the steel material in a reducing atmosphere, or in a non-oxidizing atmosphere having an oxygen partial pressure of 0.5 Pa or less, or in a vacuum having an oxygen partial pressure of 0.5 Pa or less, at a temperature in the range of 1000.degree. to 1300.degree. C.

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Tokyo, Japan

Misao Namikawa