Degassing method for manufacturing ultra-low carbon, nitrogen, sulfur steel
AssigneeUnited States Steel Corporation
InventorsYun Li, David L. Runner, Jonathan D. Youngblood, Scott R. Story
Life of this patent
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Abstract
The present disclosure provides a method of making low carbon steel. The method includes tapping the liquid steel out of a primary steelmaking furnace. Deoxidizing the liquid steel. Transferring the deoxidized liquid steel to a ladle metallurgy furnace. Removing sulfur at the ladle metallurgy furnace. Adding fluxes and arcing the liquid steel to prevent sulfur reversion. Transferring the liquid steel from the ladle metallurgy furnace to an RH degasser for carbon removal. The removal of oxygen and sulfur prior to transferring the liquid steel to the RH degasser facilitates nitrogen removal and prevents carbon pick up during the step sulfur removal.
Claims7
A method of making an ultra-low carbon steel product comprising:
- tapping liquid steel out of a primary steelmaking furnace;
- transferring the liquid steel to a ladle metallurgy furnace;
- deoxidizing the liquid steel in the ladle metallurgy furnace producing killed deoxidized liquid steel and removing sulfur from the killed deoxidized liquid steel in the ladle metallurgy furnace to prevent carbon pick up;
- adding a slag thickening material and a reducing agent containing aluminum into the killed deoxidized liquid steel prior to transferring the killed deoxidized liquid steel to a RH degasser to prevent sulfur reversion during decarburization at the RH degasser;
- and
- transferring the killed deoxidized liquid steel from the ladle metallurgy furnace to the RH degasser and oxidizing the killed deoxidated liquid steel in the RH degasser to remove carbon from the oxidized liquid steel to produce decarburized liquid steel comprising 0.003 wt. % or less carbon,
- wherein the removal of oxygen and sulfur prior to transferring the liquid steel to the RH degasser facilitates nitrogen removal and prevents carbon pick up during the step of removing sulfur.
A method of making an ultra-low carbon steel product comprising:
- tapping liquid steel out of a primary steelmaking furnace;
- transferring the liquid steel to a ladle metallurgy furnace;
- deoxidizing the liquid steel in the ladle metallurgy furnace producing killed deoxidized liquid steel and removing sulfur from the killed deoxidized liquid steel in the ladle metallurgy furnace to prevent carbon pick up;
- skimming off slag from the killed deoxidized liquid steel prior to transferring the killed deoxidized liquid steel to a RH degasser to prevent sulfur reversion during decarburization at the RH degasser;
- and
- transferring the killed deoxidized liquid steel from the ladle metallurgy furnace to the RH degasser and oxidizing the killed deoxidated liquid steel in the RH degasser to remove carbon from the oxidized liquid steel to produce decarburized liquid steel comprising 0.003 wt. % or less carbon,
- wherein the removal of oxygen and sulfur prior to transferring the liquid steel to the RH degasser facilitates nitrogen removal and prevents carbon pick up during the step of removing sulfur.
Dependencies are inferred from the claim text.