Aluminum-containing and sulfur-containing series gear steel smelting process

Abstract

The invention discloses an aluminum-containing and sulfur-containing series gear steel smelting process. Liquid iron is required to contain 0.20-0.50% of Si, less than or equal to 0.035% of S, and less than or equal to 0.110% of P, and at a temperature T greater than or equal to 1250 DEG C; lime for an electric furnace and refining is required to contain greater than or equal to 90% of CaO and less than or equal to 1.2% of SiO2, and has the activity degree of greater than or equal to 300 and the granularity of 10-40mm; a low-silicon refining agent is required to contain greater than or equal to 45% and less than or equal to 55% of CaO, less than or equal to 2.0% of SiO2, and greater than or equal to 35% and less than or equal to 40% of Al2O3. The liquid iron hot charge ratio of the electric furnace reaches up to 90%; for LF refining, a first strong and later weak deoxidization manner is adopted; at the middle-late stages, a weak deoxidizer is adopted for furnace slag maintenance to realize further deoxidization. Meanwhile, deoxidization and S removal are performed, and then an S wire is fed to obtain a certain S content; in addition, the S wire is allowed to be fed only in more than 5 minutes after the denaturalization treatment of feeding a calcium-iron wire into VD liquid steel, and therefore, the formation of CaS inclusion in a clogging material at other water gap is prevented; and at last, the castability of the liquid steel is guaranteed while excellent structural properties of the steel product are obtained, and the purity of the liquid steel is improved.

Description

technical field [0001] The invention belongs to the field of metallurgy and relates to a steel smelting process, in particular to an aluminum-sulfur-containing gear steel smelting process. Background technique [0002] Aluminum-containing and sulfur-containing series gear steel, which belongs to carburizing steel, has high strength and toughness, and good hardenability. The properties obtained after heat treatment are better than 20Cr. Small quenching deformation, good low temperature toughness, good machinability. It is generally used after carburizing and quenching or tempering. It is used to manufacture and heavy-duty quenched and tempered parts with large cross-section and carburized parts with small cross-section. It can also be used to manufacture small and medium-sized parts with medium load and less impact. It can be used instead of 20CrNi, such as gears, shafts, main shafts, and friction wheels of transmission equipment. , worm, governor sleeve, etc. The main st...

AI Technical Summary

Problems solved by technology

At the same time, due to the large amount of aluminum, titanium, and sulfur used, the castability of molten steel is poor, continuous casting in multiple furnaces cannot be realized, the surface quality of steel slabs is also poor, and the oxygen content and non-metallic oxygen content of steel are also likely to exceed the standard, which affects the quality of molten steel and increases a lot of scrap. Seriously affected production cost control