Nippon Yakin Kogyo Co., Ltd.

Asahi Seiko Company Ltd.

Masaomi Tsuda

Toshihiko Taniuchi

Yoshito Fujiwara

Hiroshi Abe

Masao Sato

Yuji Ikegami

Hiroyuki Fujii

Kazuo Ebato

Tsutomu Oomori

Stainless steels for coins and method of producing coins of stainless

Ferritic stainless steel having an excellent oxidation resistance

A continuously cast slab of Fe-Ni series alloy comprising 30-50 wt % of Ni or further 0.001-0.03 wt % of B and the balance of Fe is controlled to an eqiaxial crystal ratio of 20% or 30% in accordance with the existence or nonexistence of B content in the continuous casting and, if necessary, subjected to an electromagnetic stirring treatment or the like for controlling the eqiaxial crystal ratio and then heated at a temperature of not lower than 950.degree. C., 1000.degree. C. and 1100.degree. C. to economically produce Fe-Ni series alloys having improved effect for restraining streaks during etching.

Method of producing Fe-Ni series alloys having improved effect for

Ni-Ti intermetallic compounds are produced by subjecting a laminate of Ni foils and Ti foils to a rolling for thickness adjustment and then to a diffusion heat treatment at multistages within a particular temperature range for a particular time.

Method of producing Ni-Ti intermetallic compounds

An ingot of Fe-Ni series alloy comprising 30-80 wt % of NI or further 0.001-0.03 wt % and B and the balance of Fe is upset at a forging ratio of at least 1/1.2U, hot forged at a total sectional reduction ratio of at least 30% to form a slab, from which fine crystal grains are formed at final heat treating stage, whereby Fe-Ni series alloys for electronic and electromagnetic materials are economically produced without generating streaks at the etching.

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Kanagawa, Japan

Masaomi Tsuda