| 摘要 |
PURPOSE:To provide ferroboron which permits the quick, efficient and economical addition of <11>B at an optimum ratio to iron and steel materials by controlling the content of B, cong. boron-11 (<11>B) at a ratio of a specific value or above with respect to the total content of B and having the m.p. of a prescribed temp. or below. CONSTITUTION:The ferroboron contg. 5-30wt% B, contg. >=90wt% <11>B by the total content of B and having <=1,650 deg.C m.p. if provided. The iron and steel materials having the high content of <11>B are efficiently and economically obtd. by adding such <11>B-concd. ferroboron to a molten steel in the melting and refining stage for production of the iron and steel materials. The resultant iron and steel materials have the high ratio of <11>B with respect to the total content of B (<10>B+<11>B). The formation of He by the reaction of <10>B and neutron in the material is thus decreased even in the environment where neutrons are radiated. The good creep strength and high-temp. ductility are maintained.
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