Patent Number: 042082064
Section: claims

1. A process for producing final product castings of low alloy steel and carbon steel, said castings being characterized by superior internal and surface quality, comprising the steps of: (1) melting selected charge materials in a furnace,  (2) transferring the melt from the melting furnace into a refining vessel provided with at least one submerged tuyere,  (3) refining said melt in said refining vessel by  (4) teeming the melt into a cast product mold,  (5) permitting the melt to solidify in the mold, and  (6) removing the casting from said mold. 2. The process of claim 1 wherein the oxygen-containing gas stream is surrounded by an annular stream of a protective fluid, said protective fluid functioning to protect the tuyere(s) and surrounding refractory lining from excessive wear. 3. The process of claim 1 wherein the dilution gas is selected from the group consisting of argon, helium, hydrogen, nitrogen, carbon monoxide, carbon dioxide, steam and a hydrocarbon gas. 4. The process of claim 1 wherein the dilution gas is argon. 5. The process of claim 1 wherein the sparging gas is selected from the group consisting of argon, helium, nitrogen and steam. 6. The process of claim 1 wherein the sparging gas is argon. 7. The process of claim 1 wherein the protective fluid is selected from the group consisting of argon, helium, hydrogen, nitrogen, carbon monoxide, carbon dioxide, steam and a hydrocarbon fluid. 8. The process of claim 1 wherein the protective fluid is argon. 9. The process of claim 1 wherein the refining vessel is provided with at least two submerged tuyeres. 10. The process of claim 1 wherein the tuyeres are located in the side-wall of the vessel near the bottom, disposed horizontally, and positioned such that the tuyere axes are asymmetric. 11. The process of claim 1 wherein the absolute pressure of the injected fluids at the tuyere inlets is at least two times the absolute pressure of the fluids at the tuyere outlets.