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Introduction to Vacuum Melting Charging and Melting for Packaging Steel Strip Production
by：Hongmei
2021-03-15
Introduction to Vacuum Melting Charging and Melting for Packaging Steel Strip Production
High purity metal should be used as furnace charge during vacuum smelting, and waste materials of equivalent quality can also be used, but the surface of the waste materials should be cleaned with rust removal and degreasing. Alloying elements can be used in the form of pure metals or intermediate alloys according to their physical and chemical properties and solubility characteristics. Metals with similar activity and stable chemical properties to copper are added together with copper, and elements with high activity but low volatility are added at the later stage of refining. For volatile elements, in order to reduce evaporation loss and ensure chemical composition, inert gas is passed into the furnace to establish a pressure slightly higher than the partial pressure of volatile elements, and alloy elements are added in the final stage of smelting to reduce loss. After the charge is completely melted, stir or raise the furnace to make the composition uniform.
When charging the vacuum induction furnace, special attention should be paid to avoiding the phenomenon of 'bridging' of the charge during the melting process. The top and bottom should be loosened and tightened when charging. Elements with high melting point and not easy to oxidize should be installed in the middle and lower high temperature zone of the crucible. Elements that are easy to oxidize should be added after the molten metal is fully deoxidized. The volatile elements should be filled with inert gas in the melting chamber, and a certain furnace pressure should be maintained It is better to add it in the form of a master alloy.
After charging, the smelting chamber is closed and the vacuum is started. When the vacuum degree reaches the requirement, the material will be sent to electricity. The transmission power should be determined according to the gas and oxygen content in the charge. The power transmission is compatible with the gas release rate and pumping rate of the molten state to avoid the rapid precipitation of a large amount of gas, which leads to violent boiling of the molten pool and splashing.
When the molten metal is completely melted and no bubbles escape from the surface of the molten pool, the smelting shifts to the refining period. The main task of the refining period is to improve the purity of the liquid metal for further alloying
化, especially the alloying of active elements creates conditions. The refining process includes reactions such as deoxygenation, degassing and removal of volatile and harmful trace elements. At the same time, adjust the temperature of the molten pool and carry out alloying. In order to shorten the smelting time, the melted melt can be poured into a vacuum furnace crucible under normal pressure, and then the vacuum chamber is closed, vacuumed, and electrified for refining.
The alloying operation can be carried out after the refining is completed. When adding metal, avoid splashing. After adding, stir 1-2 with high power to accelerate the melting and uniform distribution of the alloy.
High purity metal should be used as furnace charge during vacuum smelting, and waste materials of equivalent quality can also be used, but the surface of the waste materials should be cleaned with rust removal and degreasing. Alloying elements can be used in the form of pure metals or intermediate alloys according to their physical and chemical properties and solubility characteristics. Metals with similar activity and stable chemical properties to copper are added together with copper, and elements with high activity but low volatility are added at the later stage of refining. For volatile elements, in order to reduce evaporation loss and ensure chemical composition, inert gas is passed into the furnace to establish a pressure slightly higher than the partial pressure of volatile elements, and alloy elements are added in the final stage of smelting to reduce loss. After the charge is completely melted, stir or raise the furnace to make the composition uniform.
When charging the vacuum induction furnace, special attention should be paid to avoiding the phenomenon of 'bridging' of the charge during the melting process. The top and bottom should be loosened and tightened when charging. Elements with high melting point and not easy to oxidize should be installed in the middle and lower high temperature zone of the crucible. Elements that are easy to oxidize should be added after the molten metal is fully deoxidized. The volatile elements should be filled with inert gas in the melting chamber, and a certain furnace pressure should be maintained It is better to add it in the form of a master alloy.
After charging, the smelting chamber is closed and the vacuum is started. When the vacuum degree reaches the requirement, the material will be sent to electricity. The transmission power should be determined according to the gas and oxygen content in the charge. The power transmission is compatible with the gas release rate and pumping rate of the molten state to avoid the rapid precipitation of a large amount of gas, which leads to violent boiling of the molten pool and splashing.
When the molten metal is completely melted and no bubbles escape from the surface of the molten pool, the smelting shifts to the refining period. The main task of the refining period is to improve the purity of the liquid metal for further alloying
化, especially the alloying of active elements creates conditions. The refining process includes reactions such as deoxygenation, degassing and removal of volatile and harmful trace elements. At the same time, adjust the temperature of the molten pool and carry out alloying. In order to shorten the smelting time, the melted melt can be poured into a vacuum furnace crucible under normal pressure, and then the vacuum chamber is closed, vacuumed, and electrified for refining.
The alloying operation can be carried out after the refining is completed. When adding metal, avoid splashing. After adding, stir 1-2 with high power to accelerate the melting and uniform distribution of the alloy.
