RU2104311C1 - Method of alloying steel by manganese - Google Patents

Abstract

FIELD: ferrous metallurgy. SUBSTANCE: method includes smelting and deoxidizing steel, tapping it into ladle, adding oxide manganese-containing materials, reducing agents, and flux. All these materials are added simultaneously in the form of filler of shell powder wire in amount 20-55 kg x N per 1 t steel, where N is required increment of manganese content in final steel expressed in wt %. Reducing agents utilized are materials selected from the group including aluminum and/or ferrosilicon or ferrosilicon and silicocalcium, and flux is feldspar. Powder mixture contains 66-75% of oxide manganese-containing material, 1-5% of feldspar, and reducing agent to 100%. EFFECT: facilitated extra- furnace treatment of smelt. 6 cl, 2 tbl

Description

 The invention relates to ferrous metallurgy, in particular to alloying a metal with manganese by out-of-furnace treatment of the melt with cored wire.

 A known method of alloying a metal with manganese by introducing into the melt a flux-cored wire wire containing a powder of 80% ferromanganese [1].

 The disadvantages of this method are: the high complexity of the manufacture of the powder of the desired particle size distribution from lump ferromanganese, increased material and energy costs in the production of ferromanganese, especially in the multi-stage production of metal manganese, a high probability of contamination of the metal with oxide and nitride inclusions formed in the melt during the interaction contained in manganese alloys associated elements with oxygen and nitrogen, low through extraction of mar manganese ores and concentrates.

 The closest in technical essence and the achieved result to the proposed one is the method of alloying steel with manganese, which consists in the fact that after the metal is released into the ladle, the low-phosphorus manganese-containing slag of the ferroalloy production is produced on the melt, the reducing agent and lime in an amount ensuring slag basicity of 2.0-3 , 5, oxygen is supplied to the bucket surface for 3–30 s [2].

 The disadvantages of this method are the instability of the reduction of manganese due to the additional consumption of the reducing agent for deoxidation of the oxidizing slag entering the ladle, the increased fumes of the reduced manganese and the reducing agent due to the interaction with air oxygen and oxygen blast on the melt surface, the heterogeneous composition of the finished steel according to the manganese content, as supplying oxygen for 3-30 s to the surface of the bucket is not enough to equalize the entire volume of the bucket, high losses of manganese oxide rusting material, in particular low-phosphorous manganese-containing slag of ferroalloy production, during storage and transportation, increased environmental pollution over the ladle with manganese vapor.

 The invention eliminates these disadvantages.

 This is achieved by the fact that in the method of alloying steel with manganese, which includes the smelting of steel and the introduction of reducing agents, an oxide of manganese-containing material and flux into the melt in the form of a mixture of powders of an oxide of manganese-containing material with one or two materials from the following group: aluminum, ferrosilicon, silicocalcium and flux - fluor spar, in the following ratio of components in the mixture, wt.%: oxide manganese-containing material 66-75; materials selected from the group: aluminum, ferrosilicon, silicocalcium and flux — the rest, and the mixture in the form of a filler of a flux-cored wire sheath is introduced into the melt in an amount of 20-55 N • kg per ton of steel, where N is the required increase in the manganese content in steel, wt .%.

 In particular cases, the mixture may have the following compositions, wt.%: 1) manganese oxide material 66-75; aluminum 22-30; fluorspar 1-5; 2) oxide manganese-containing material 66-75; ferrosilicon FS65 15-20; silicocalcium SK30 10-15; fluorspar 1-3; 3) manganese oxide material 66-75; aluminum 16-21; ferrosilicon FS65 12-17; fluorspar 1-5.

 The mixture can be introduced into the melt in the form of a flux cored wire with a diameter of 9-18 mm at a speed of 1.0-4.0 m / s or in the form of coated briquettes.

 The proposed method allows to reduce material and energy costs for alloying, and especially for finishing steel, to improve the environment, improve the quality of the metal, eliminate the rejection of heats due to misses in the given chemical composition for manganese, to ensure a stable content of manganese in the metal from heat to heat.

At the temperature of liquid steel in a steel ladle, the vapor pressure of manganese is approximately 0.01 MPa. This indicator indicates that when the flux-cored wire is immersed in the metal of the casting ladle to a depth of more than 0.5 m, the ferrostatic pressure of the liquid will significantly exceed the vapor pressure of manganese and, after the reduction reactions from oxides are completed, manganese is almost completely dissolved in the metal and its content in steel increases by specific set value. In a ladle with liquid steel at a temperature of 1570-1620 ^o C, the flux-cored wire melts in 1-3 s depending on the speed of its input. The optimal rate of flux-cored wire entry into the melt allows it to reach its lower horizons at a depth of 0.5-0.8 bucket heights and thereby ensure the most effective course of reduction reactions and the transition of manganese into the solution. The direct contact of manganese oxides after melting of the steel shell with reducing agents is carried out in the local zones of the liquid metal and under the influence of the formed conventional flows extends to its entire volume. Depending on the composition of the flux cored wire fillers, the reactions of reduction of manganese oxides to metallic manganese due to reducing agents are accompanied by various thermal effects and the formation of slags with a relatively low melting point. Moreover, the reduction products of manganese oxides of the type Al ₂ O ₃ , SiO ₂ and CaO form relatively low-melting slags, which are easily removed from the metal and the purity of steel by oxide and sulfide inclusions significantly increases.

 The introduction of the mixture in an amount of 20-55 N • kg per 1 ton of steel, where N is the increase in the manganese content in the steel, wt.%, Ensures guaranteed receipt of the required manganese content in the steel.

 The introduction of the mixture in the form of a sheathed flux-cored wire improves the stability of the results and the manufacturability of steel alloying processes, and the wire feed speed of 1.0-4.0 m / s ensures the delivery of the mixture to a given melt depth without evaporation of the formed manganese metal.

 The method is as follows.

 Example 1. Perform steel grade 08Yu. From the steelmaking unit, steel is released into a bucket with a capacity of 5.00 t and deoxidized with aluminum in the calculation of obtaining it in a metal of 0.03-0.05 wt.%. Then, a sheathed flux-cored wire with a filler consisting of powders of oxide manganese-containing material (manganese concentrate containing 44% manganese in oxides) 72%, aluminum 23% and fluorspar 5% is introduced into the bucket with a filler consumption of 6.85 kg / t of steel with input speed 2.4 m / s. After entering the wire, the metal is stirred with argon for 2 minutes and poured into 1-ton ingots. Before and after the input of the wire, metal samples are taken for chemical analysis. Samples are taken from rolled stock obtained from ingots to determine the score of non-metallic inclusions.

 Similarly, melts NN 2, 3, and 4 were carried out, as well as melting with alloying steel with manganese according to the known method [2] in the smelting of steel grade st. 3sp.

 The compositions of the mixtures used are given in table. one.

 The test results of the obtained steels and the technological parameters of the input mixtures in the swimming trunks are given in table. 2.

 As you can see, the proposed method of alloying steel with manganese allows to reduce the consumption of materials, including by increasing the assimilation of manganese (extraction of manganese from oxide manganese-containing material), to increase the degree of desulfation of steel and reduce metal contamination by non-metallic inclusions without the use of additional refining, improve environmental conditions and eliminate manganese chemical analysis rejects.

Claims (2)

 1. The method of alloying steel with manganese, including the smelting and deoxidation of steel, releasing it into the ladle, introducing into the steel after releasing the oxide manganese-containing material, reducing agents and flux into the ladle, characterized in that the introduction of the oxide of manganese-containing material, reducing agents and flux into the steel is carried out simultaneously in in the form of a filler of a sheathed cored wire in an amount of 20 55 kg x N per 1 ton of steel, wt. as reducing agents, a material selected from the group of aluminum and / or ferrosilicon or ferrosilicon and silicocalcium is used, and fluorspar is used as a flux, with manganese oxide material, fluorspar and a material selected from the group of aluminum and / or ferrosilicon or ferrosilicon and silicocalcium is used in the form of a mixture of powders in the following ratio of components in the mixture, wt. Manganese oxide material 66 75
Feldspar 1 5
Material selected from the group: aluminum and / or ferrosilicon or ferrosilicon and silicocalcium
2. The method according to p. 1, characterized in that as a filler sheathed flux-cored wire using a mixture of powders of oxide manganese-containing material, fluorspar and aluminum in the following ratio of components in the mixture, wt. Manganese oxide material 66 75
Feldspar 1 5
Aluminum 22 30
3. The method according to p. 1, characterized in that as a filler sheathed flux-cored wire using a mixture of powders of oxide manganese-containing material, fluorspar, ferrosilicon and silicocalcium in the following ratio of components in the mixture, wt. Manganese oxide material 66 75
Feldspar 1 5
Ferrosilicon 15 20
Silicocalcium 10 15
4. The method according to p. 1, characterized in that as a filler sheathed flux-cored wire using a mixture of powders of oxide manganese-containing material, fluorspar, aluminum and ferrosilicon in the following ratio of components in the mixture, wt. Manganese oxide material 66 75
Feldspar 1 5
Aluminum 12 18
Ferrosilicon 10 17
5. The method according to p. 1, characterized in that the mixture in the form of a filler sheath flux-cored wire is introduced into the melt with a wire speed of 1.0 to 4.0 m / s  6. The method according to p. 1, characterized in that as the oxide manganese-containing material using malophosphorous slag ferroalloy production.

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