Sumitomo Metal Industries, Inc.

Takeo Yazawa

Hideaki Yamamoto

Kazuhiro Ogawa

Yoshio Tarutani

Akira Seki

Hideo Morisaki

Kunihiko Ushio

Motomichi Kanbe

Kazuhiro Ishida

Kazuhiko Ishida

A method for producing a stainless steel three-ply clad sheet for a fuel cell separator comprises heating a source blank and then performing rough rolling, hot rolling and cold rolling thereto, whereby the clad steel sheet for the fuel cell separator or a solid polymer type fuel cell separator thereby is obtained. The source blank for the clad steel sheet is composed of a stainless steel utilizing 0 to 0.3% B as a core component and a stainless steel containing 0.3 to 2.5% B as face component. The source blank is made using face components, a core component, tabs and protectors and performing steps including bonding of the tabs and protectors to the face components, removing portions of the tabs and protectors, piling of the face components to the core component, and further bonding of the face and core components together to form the source blank.

Source blank for stainless steel three-ply clad sheet, production methods of clad steel plate and sheet for solid polymer type fuel cell separator, and solid polymer type fuel cell separator

A stainless steel slab containing B, wherein a protecting material is joined onto at least two faces across the bloom from each other in a stainless steel bloom containing B of 0.3&#x2013;2.5 mass %, being integrated into one-piece by forming a weld metal comprising a stainless steel with chemical composition that satisfies the relationship expressed by following formulas (1)&#x2013;(4), and a method to produce a steel product by rolling said slab. Further, it is preferable to interpose an insert material between above stainless steel bloom and above protecting material in bonding process.15&#x2266;Cr,&#x2003;&#x2003;(1)4&#x2266;Cr&#x2212;Ni&#x2266;17,&#x2003;&#x2003;(2)Cr=Cr+1.5 Si+Mo&#x2212;5 B,&#x2003;&#x2003;(3)Ni=Ni+30 (C+N)+0.5 Mn&#x2003;&#x2003;(4) Herein, each symbol of a chemical element designates the content (mass %) of relevant chemical element contained in steel. Accordingly, it makes it possible to subject a stainless steel slab containing B to hot working without generating edge cracking, so as to be used as a source material of a neutron shielding container and a separator of a fuel cell.

Stainless steel product containing B and method for production thereof

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Osaka, Japan

Takeo Yazawa