Smelting method capable of shortening Consteel electric furnace smelting cycle

Abstract

The invention discloses a smelting method capable of shortening the Consteel electric furnace smelting cycle. According to the method, the smelting process is divided into a slag melting period, a dephosphorization period and a carbon blowing and temperature rising period; furthermore, the dephosphorization rate in the smelting process is influenced by different slag system components in the slagmelting period and the carbon blowing and temperature rising period, wherein in the slag melting period, the temperature starts from 1300 DEG C and is increased to 1520 DEG C at constant speed, and slag I is added when the temperature in the furnace reaches to 1450 DEG C, so that the target slag system components in the dephosphorization period are that the FeO content is less than or equal to 25percent by weight, the MgO content is 4 to 5 percent by weight and the slag basicity R is equal to 2.5 to 3.0; in the dephosphorization period, the temperature starts from 1520 DEG C and is increasedto 1580 DEG C at constant speed, and the process enters the carbon blowing and temperature rising period when the components of steel samples meet that carbon is more than 0.35 percent by weight and phosphorus is less than 0.030 percent by weight; and in the carbon blowing and temperature rising period, the temperature starts from 1580 DEG C and is increased to 1650 DEG C at constant speed, slag II is added at the beginning, so that the components of the target slag system in the carbon blowing and temperature rising period are that the FeO content is 15 to 20 percent by weight, the MgO content is 4 to 5 percent by weight and the slag basicity R is equal to 3.0 to 3.5. The smelting method capable of shortening the Consteel electric furnace smelting cycle has the following beneficial effect: the dephosphorization rate in the electric furnace smelting process is influenced by different slag system components, so that the smelting period is shortened.

Description

technical field [0001] The invention relates to a smelting method, in particular to a smelting method capable of shortening the smelting cycle of a Consteel electric furnace, and belongs to the technical field of metallurgy. Background technique [0002] At present, the smelting method adopted by our company to smelt special steel with Consteel electric furnace is the traditional Consteel electric furnace smelting method. The specific steps of this method are as follows: [0003] 1. At the beginning of smelting, add molten iron, the amount of which is 60% to 90% of the total loading; [0004] 2. After mixing 2 / 3 of the molten iron, the oxygen lance starts blowing oxygen to raise the temperature, and the flow rate is 2500Nm 3 / min~3000Nm 3 / min, add slag after blowing oxygen for 10 minutes; [0005] 3. The slag material is randomly added depending on the slag condition in the furnace, 500kg of lime and 500kg of limestone are added in each batch, and the total amount of ash...

AI Technical Summary

Problems solved by technology

[0009] (1) The addition of scrap steel is delayed, and a large amount of oxygen is supplied in the early stage of smelting, resulting in high local temperature in the furnace, high content of FeO in the slag, severe carbon-oxygen reaction, and a large amount of slag in the furnace overflows from the furnace door. When the slag has not completely slag, it will flow out from the furnace door with the slag, and the slag will not keep up with it in the later stage, and the FeO and SiO in the slag will 2 The content of slag is low, the slag formation is slow during the smelting process, the fluidity and foaming of the slag are poor, and the smelting time is prolonged;

[0010] (2) In the middle stage of smelting, high temperature is generated in the furnace, which cannot meet the thermodynamic conditions for dephosphorization, resulting in difficulty in dephosphorization during the smelting process;

[0011] (3) At the end of the smelting process, when the carbon content in the steel is low, the molten steel is overoxidized, and the content of FeO in the slag is relatively high, and the molten steel is prone to rephosphorization at high temperature before tapping, and dephosphorization operation is required again, and the smelting cycle becomes longer

[0012] Due to the relatively long smelting cycle of the Consteel electric furnace, the operating cost of the Consteel electric furnace has increased

[0013] In addition, at the end of smelting, when the carbon content in the steel is low, the peroxidation of molten steel will be serious, which will increase the smelting cost and operational difficulty of subsequent refining furnaces

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