3results about How to "Reduce secondary oxidation" patented technology

This invention discloses a method for controlling sulfides in sulfur-containing gear steel, belonging to the field of metallurgical technology, including converter, LF refining, RH refining, and continuous casting processes. Converter process: molten steel tapping temperature 1630±20℃, carbon-oxygen product controlled below 0.0020; LF refining process: aluminum content in molten steel controlled at 0.035-0.045%, LF slag composition adjusted to R: 1.5-2.5, FeO+MnO: 1.0-2.0%; RH refining process: ferrotitanium added in one step to adjust the composition appropriately; Continuous casting process: argon-blown stopper rods and submerged entry nozzles are used for continuous casting, and 150-200 kg of low-basicity tundish covering agent is added to the tundish. The sulfur-containing gear steel produced by this invention can be continuously drawn for more than 10 heats, and the level of Class A inclusions can be stably controlled at A coarse ≤ 1.0 grade and A fine ≤ 1.5 grade, with a pass rate of over 99.9%.

This invention belongs to the field of die casting in metallurgical processes, and particularly relates to a method for improving steel ingot yield using high-temperature CO2 gas. The method includes: 1) filling the steel ingot mold and runner with high-temperature CO2 before casting, and preheating the mold and runner to 400-700°C; 2) during casting, after the molten steel enters the ingot mold, the interior of the mold is a sealed space filled with CO2 atmosphere, and the CO2 heated by the molten steel is circulated back to the heat exchange furnace. No protective slag or heating agent is used during the casting process; 3) after casting, during the solidification process of the steel ingot, the high-temperature CO2 gas in the heat exchange furnace is used to replenish the CO2 gas in the ingot mold, resulting in slow solidification of the steel ingot and sufficient riser feeding. The advantages are: using high-temperature CO2 gas as an isolation, heat transfer, and insulation medium, and through a closed circulating heat exchange system, precise temperature and atmosphere control are achieved during the casting and solidification process of the steel ingot. By optimizing feeding and reducing waste, the steel ingot yield can be increased to over 90%.

This invention relates to the field of tundish covering agent technology, and specifically discloses a double-layer tundish covering agent pellet, comprising the following components by mass percentage: limestone 30%–37%, dolomite 18%–28%, lightly calcined magnesia powder 10%–15%, expanded perlite 22%–30%, expanded graphite 1%–4%, binder 1%–3%, and magnesium chloride 2%–4%. The purpose of this invention is to solve the problem of potential quality hazards in molten steel caused by the melting of rice husks in traditional double-layer heat-insulating covering agents during steelmaking.