Product and method for carrying out magnesium or magnesium-calcium treatment on molten steel

Abstract

The invention discloses a product and a method for carrying out magnesium or magnesium-calcium treatment on molten steel, and belongs to the technical field of metallurgy. The product for carrying out the magnesium or magnesium-calcium treatment on the molten steel is composed of a sealed shell and an alloying material packaged in the shell, the alloying material comprises magnesium oxide, a composite reducing agent and a stable diluent, wherein the composite reducing agent is used for reducing magnesium in the magnesium oxide, and the stable diluent is used to provide a substance that forms a miscible alloy melt with magnesium. According to the technical method of the invention, the product is inserted into the deep position of molten steel, a reduction reaction of magnesium oxide is excited through the energy of the molten steel, magnesium metal is stabilized, diluted and dispersed by forming the magnesium alloy miscible melt through gradual reduction, rapid evaporation of magnesium in the magnesium modification treatment process of inclusions in steel can be effectively inhibited, the gasification and oxidation loss of magnesium is reduced, the yield of the magnesium element in the steel is improved and stabilized, and the purity of the molten steel after magnesium treatment is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and more specifically relates to a product and a method for treating molten steel with magnesium or magnesium-calcium by using magnesium oxide instead of magnesium alloy. Background technique [0002] Magnesium or magnesium-calcium composite treatment of molten steel to improve the performance of steel is a new process for modifying and denaturing inclusions in steel that has attracted more and more attention from metallurgists after the previous calcium treatment and is constantly exploring. method. Adding magnesium to molten steel can carry out composite deoxidation with oxygen-controlling elements such as aluminum and calcium more deeply, and generate magnesium spinels with smaller size and more dispersed distribution. These spinels will become the core of subsequent MnS-MgS precipitation, The inclusions formed by the package are also highly dispersed, miniaturized and have a certain resis...

AI Technical Summary

Problems solved by technology

[0004] 1. In the existing magnesium treatment methods, magnesium alloys with higher magnesium content are added to molten steel for magnesium treatment. However, since the melting point of magnesium alloys is still very low and the thermal conductivity is very good, when the heat of molten steel passes through the cored wire shell When it is imported, it will heat up and melt quickly, and the explosive magnesium evaporation will still occur at a very high melting rate.

[0005] 2. In the existing magnesium treatment methods, metal alloys such as aluminum-magnesium, calcium-magnesium or calcium-silicon-magnesium with low magnesium content are added to molten steel for magnesium treatment. Although this method reduces the vapor pressure of magnesium to a certain extent, it does not The magnesium content of the alloys used is mostly above 15%. In the microscopic molten pool after the rapid melting of the magnesium alloy, the accumulation of the contained magnesium element will make the partial pressure of the vapor still high, at least above 0.35Mpa. The high temperature and static pressure cannot effectively suppress the occurrence of violent evaporation and escape of magnesium at all.

[0006] 3. In the existing magnesium treatment methods, calcium and magnesium alloys are added to molten steel for magnesium and calcium composite treatment. Metal calcium in molten steel also has a relatively high vapor pressure. During composite treatment, although the calcium-magnesium alloy reduces the vapor pressure of magnesium, the low partial pressure of magnesium in the calcium vapor generated at the same time will promote the evaporation of magnesium and escape with the calcium vapor. The joint action of calcium and magnesium vapor will also affect The absorption of magnesium by molten steel ultimately improves the yield of magnesium slightly

[0007] 4. During the magnesium treatment process, the strong evaporation and escape of magnesium makes the molten steel in the ladle violently tumbling and severely exposed. The aluminum loss in the steel is large, the nitrogen increase is serious, and the molten steel is polluted

[0010] Due to the above-mentioned problems of magnesium metal and its alloys, especially the severe molten steel splashing during the magnesium treatment process has seriously restricted the application and promotion of magnesium treatment of molten steel, researchers related to the entire industry around the world have been trying to break through this bottleneck , but so far there have been no more successful public cases