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US 12,571,062 B2Granted
Process for producing raw steel and aggregate for production thereof
AssigneeThyssenKrupp Steel Europe AG
InventorsMatthias Weinberg, Frank Ahrenhold
Life of this patent
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Abstract
The invention relates to a process for producing low-nitrogen crude steel. This process includes melting directly reduced iron and/or scrap in a melting furnace with arc resistance heating to give a metallic melt and a slag. The metallic melt is removed from the melting furnace and used to charge a converter. The metallic melt is refined in the converter to give liquid crude steel. The liquid crude steel is tapped having a nitrogen content [N] of not more than 50 ppm, especially of not more than 30 ppm.
Claims13
A process for producing low-nitrogen crude steel, comprising the following process steps:
- melting directly reduced iron and/or scrap in a melting furnace with arc resistance heating with a reducing atmosphere to give a metallic melt and a slag,
- removing the metallic melt from the melting furnace and using it to charge a converter,
- refining the metallic melt, wherein the nitrogen content [N] is lowered when the nitrogen content [N] of the metallic melt is above 50 ppm, or kept low or lowered further when the nitrogen content [N] of the metallic melt is below 50 ppm, in the converter to give liquid crude steel and tapping the liquid crude steel having a nitrogen content [N] of 50 ppm or less, wherein the metallic melt, immediately prior to the refining, has a ratio of carbon content to nitrogen content [C]/[N] of at least 20.
Dependencies are inferred from the claim text.