| 摘要 |
PURPOSE:To obtain steel fibers for reinforcement of concrete which generate effective tension for the forces from all the directions by compressing the opposite surfaces of a slab of a rectangular strip shape or the like with a press or the like, and subjecting the same to rolling and coining thereby forming juts, projection parts and recess parts. CONSTITUTION:A steel strip 1 is fed intermittently onto a cutter blade 3 and a punch 2 is lowered onto a lower die 4, whereby the strip is cut to steel pieces 1'' of a rectangular strip shape. The punch 2 is further lowered to compress the pieces 1'' between the punch 2 and the die 4. Since a large number of shallow grooves are provided at equal intervals to the punch 2 and the die 4, the pieces 1'' are coined by compression, whereby the steel fibers having rugged parts consisting of juts 13, recess parts 15 and projection parts 14 are obtained. The steel fibers of such shape generate the tension effective for all the forces from the directions perpendicular, normal and tangential to the surfaces of the steel fibers in the concrete in which they are embedded. |
