| 摘要 |
PROBLEM TO BE SOLVED: To provide a device for charging an additive with which the improvement and the stability in the yield of a free-cutting steel can be obtained by charging the additive into molten steel at a low speed and a fixed speed. SOLUTION: In the charging device for additive charging Pb grains 24 into the molten steel 19 in a ladle 17, this device is provided with a weighing hopper 3 for weighing the Pb grains, a rotary valve 8 for feeding out the Pb grains 24 stored in this weighing hopper 3 and a butterfly valve 11 arranged below the rotary valve 8 and changeable to the opening/closing in the pipe line for fed-out Pb grains 24 and constituted so that the size of a gap between the tip part of the blade of a rotor 6 in the rotary valve 8 and the inner surface of a casing for putting the rotor 6 becomes 2-10 times of the grain diameter of the Pb grains. COPYRIGHT: (C)2005,JPO&NCIPI
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