Sumitomo Metal Industries, Inc.

Kazuhiro Ishida

Kazuhiro Ogawa

Hideaki Yamamoto

Takeo Yazawa

Hideo Morisaki

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.

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Kitakyushu, Japan

Kazuhiro Ishida