Loading patent…
AssigneeHitachi Metals, Ltd.
InventorsShin-ichiro Yokoyama, Tsutomu Inui, Hideya Yamada
Estimating the term…
Provided is a composite magnetic member made of a single material combining a ferromagnetic portion and a non-magnetic portion in which the ferromagnetic portion has better soft magnetism than conventional members and the non-magnetic portion has the same stable characteristic as conventional members. A method of producing the ferromagnetic portion of the member and a method of forming the non-magnetic portion are also provided. The composite magnetic member is made of an Fe—Cr—C-base alloy steel containing 0.1 to 5.0 weight % Al and has a ferromagnetic portion with a maximum magnetic permeability of not less than 400 and a non-magnetic portion with a magnetic permeability of not more than 2. In this member the number of carbides with a grain size of not less than 0.1 μm is regulated to not more than 50 in an area of 100 μm2 and the proportion of the number of carbides with a grain size of not less than 1.0 μm to the number of all carbides is controlled to not less than 15%.
A composite magnetic member made of an Fe—Cr—C-base alloy steel containing 0.1 to 5.0 weight % Al, comprising a ferromagnetic portion with a maximum magnetic permeability of not less than 400 and a non-magnetic portion with a magnetic permeability of not more than 2, said ferromagnetic portion being provided with carbides so that a number of carbides with a grain size of not less than 0.1 μm is regulated to not more than 50 in an area of 100 μm2 and so that a proportion of the number of carbides with a grain size of not less than 1.0 μm to the number of said carbides of not less than 0.1 μm in grain size in an area of 100 μm2 is regulated to be not less than 15%.
A composite magnetic member made of an Fe—Cr—C-base alloy steel containing 0.1 to 5.0 weight % Al, comprising a ferromagnetic portion with coercive force of not more than 1000 A/m and a non-magnetic portion with a magnetic permeability of not more than 2, said ferromagnetic portion being regulated to have coarse grains having JIS grain size number not more than 14.
A method of producing a ferromagnetic portion of a composite magnetic member, comprising the steps of hot working an Fe—Cr—C-base alloy steel containing 0.1 to 5.0 weight % Al at a temperature not more than 1100° C., annealing said alloy steel at least once at a temperature not more than A3 transformation point so that said ferromagnetic portion is obtained in which a number of carbides with a grain size of not less than 0.1 μm is regulated to not more than 50 in an area of 100 μm2 and in which a proportion of the number of carbides with a grain size of not less than 1.0 μm to the number of said carbides of not less than 0.1 μm in grain size in an area of 100 μm2 is regulated to not less than 15%.
A method of forming a non-magnetic portion of a composite magnetic member, comprising the steps of hot working an Fe—Cr—C-base alloy steel containing 0.1 to 5.0 weight % Al at a temperature not higher than 1100° C., annealing said alloy steel at least once at a temperature not higher than A3 transformation point so that said ferromagnetic portion is obtained in which a number of carbides with a grain size of not less than 0.1 μm is regulated to not more than 50 in an area of 100 μm2 and in which a proportion of another number of carbides with a grain size of not less than 1.0 μm to the number of carbides of not less than 0.1 μm in grain size in an area of 100 μm2 is regulated to not less than 15%, heating a part of said ferromagnetic portion in a temperature range of 1050° C. to the melting point, and cooling said heated part so that said non-magnetic portion is obtained.
Dependencies are inferred from the claim text.