| 摘要 |
PURPOSE:To uniformly incorporate lead into a steel and to produce a lead free cutting steel having excellent machinability in the stage of producing the lead free cutting steel by adding a complex of lead mixed with specific material grains having high reactivity as the 2nd phase grains to the flow of the molten steel from a ladle to a tundish. CONSTITUTION:A Pb wire of 1-15mm diameter or hooped Pb complex 12 of 1-10mm thickness and <=20mm width added with the material grains of Ca, Mg, Ba, Na or the alloys thereof or rare earth metals, etc., having the high deoxidation and desulfurization reaction as the 2nd phase material having the high reactivity is directly added to the molten steel flow 14 in the stage of admitting the molten steel 4 from the ladle 2 into the tundish 6. Pb is uniformly dispersed and distributed into the molten steel by the energy or evaporation energy generated when the above-mentioned 2nd phase grains react with the molten steel. The free cutting steel contg. 0.03-0.4wt% Pb is thus produced.
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