Patent Number: 6,255,005

Title: Composite magnetic member, method of producing ferromagnetic portion of same, and method of forming non-magnetic portion of same

Abstract: 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 .mu.m is regulated to not more than 50 in an area of 100 .mu.m.sup.2 and the proportion of the number of carbides with a grain size of not less than 1.0 .mu.m to the number of all carbides is controlled to not less than 15%.

Inventors: Yokoyama; Shin-ichiro (Yasugi, JP), Inui; Tsutomu (Yonago, JP), Yamada; Hideya (Yasugi, JP)

Assignee: Hitachi Metals, Ltd.

International Classification: C22C 38/40 (20060101); C22C 38/06 (20060101); C22C 38/00 (20060101); C21D 6/00 (20060101); H01F 1/03 (20060101); B32B 015/00 ()

Expiration Date: 07/03/2018