NOVEL ADDITIVE COMPRISING LEAD AND/OR A LEAD ALLOY INTENDED TO TREAT BATHS OF LIQUID STEEL.

摘要

The present invention relates to an additive in the form of flux-cored wire intended for treating baths of liquid steel with a view to obtaining steels having a high lead content. The additive comprising metallic lead and/or one or more lead alloys according to the invention is intended to treat baths of liquid steel, and is in the form of flex-cored wire composed of a metal sheath and a finely divided filling material, the latter being composed of a powder of metallic lead and/or of lead alloy and of a powder containing a material capable of releasing a gas, which is inert with respect to the liquid steel, at the temperature of the liquid steel bath. Characteristically, said powder of metallic lead and/or of lead alloy consists of a particle size fraction GR between 200 mum and 500 mum and in that said particle size fraction GR has the following characteristics: - through a 200 mum sieve: GR < 5%; - through a 300 mum sieve: 90% ≈ GR ≈ 10%; - through a 400 mum sieve: 40% GR < 100%; - through a 500 mum sieve: 100% ≈ GR ≈ 90%.