A smelting method for producing IF steel with low oxygen level in the whole process

Abstract

The invention discloses a smelting method for producing IF steel with low oxygen level in the whole process, and belongs to the technical field of iron and steel smelting. The steps of the present invention are as follows: step 1: slag dumping at the end of converter steel smelting, leaving 10-15 tons of slag in the converter, adding 50-100 kg of coke powder to remove oxygen in the slag, and then performing slag splashing to protect the furnace; step 2: charging the converter ;Step 3: Converter main blowing; Step 4: After the converter main blowing, measure the molten steel temperature and carbon content through the sub-lance, and control the auxiliary blowing oxygen amount according to the measured value; Step 5: After the auxiliary blowing, before tapping Bottom blowing for 30 seconds; Step 6: Converter tapping; Step 7: Molten steel enters the RH process; Step 8: After the ladle is lifted, turn on the vacuum pump to vacuum and decarburize. The invention can reduce the degree of peroxidation of molten steel in converter tapping, reduce the oxidizability of ladle top slag, and reduce deoxidized inclusions Al 2 o 3 The amount of production is increased, the cleanliness level of molten steel is improved, and the cost is reduced, which has significant economic benefits.

Description

technical field

[0001] The invention relates to the technical field of iron and steel smelting, and more specifically, relates to a smelting method for producing IF steel with low oxygen level in the whole process. Background technique

[0002] IF steel has excellent stamping and forming properties. At present, the smelting of IF steel is mainly produced by the technological process of "converter → alloy fine-tuning station → RH refining furnace → slab continuous casting". In the above-mentioned processes, on the one hand, the two operation sub-units of converter dephosphorization and RH decarburization require molten steel There is a certain amount of oxygen content, and the oxygen content at the end of the converter is too high, which will lead to strong oxidation of the final slag of the converter that inevitably enters the ladle, affecting the castability of molten steel in the continuous casting process; during the RH decarburization period, the oxygen content of molten...

Examples

Embodiment 1

[0027] from figure 1 It can be seen that the smelting method for producing IF steel in a whole process low-oxygen position of the present embodiment, the steps are:

[0028] Step 1: After the smelting of the converter steel, the slag is poured, and 10-15 tons of slag is left in the converter, and 50-100 kg of coke powder is added to remove the oxygen in the slag, and then the slag splashing operation is carried out to protect the furnace;

[0029] The chemical composition requirements of IF steel are: C≤0.0050%, Si≤0.01%, Mn: 0.08~0.25%, P≤0.015%, S≤0.008%, Als: 0.030~0.050%, Ti: 0.030~0.070%;

[0030] The slag composition range of converter slag is: TFe: 12-25%, CaO: 40-60%, SiO 2 : 10~18%, MnO: 2~3%, MgO: 3~6%;

[0031] Composition of coke powder is C≤94%, H2O≤0.020%, S≤0.022%, volatile + ash≤5%, particle size 5-15mm;

[0032] Step 2: Converter charging; the molten iron-scrap linkage ratio mode is adopted, and the amount of molten iron and scrap added is based on the prin...

Embodiment 2

[0064] A kind of smelting method of producing IF steel in the low oxygen position of the whole process of the present embodiment, its steps are:

[0065] Step 1: After the smelting of the last furnace of steel in the converter, the slag is dumped, leaving 13 tons of slag in the converter, adding 75 kg of coke powder to remove the oxygen in the slag, and then performing slag splashing to protect the furnace;

[0066] Step 2: Converter charging: adopt the molten iron-scrap linkage ratio mode, add 298t of molten iron and 33t of scrap steel, of which molten iron Si: 0.28%;

[0067] Step 3: Converter main blowing: Calculated according to “lime addition = 2.14×W[Si]×R×1000 / A”, the total lime addition is 27.1kg / t steel, where W[Si]: 0.28 %, R: 4, W(CaO): 90%, W(SiO 2): 0.35%: tapping amount: 297t, you need to add 8.0t of lime: 4 minutes before blowing: add lime to the converter in 3 batches, keep the lance position at 2.7m, and the oxygen flow rate of the top lance is 63000m 3 / h, ...

technical field

[0001] The invention relates to the technical field of iron and steel smelting, and more specifically, relates to a smelting method for producing IF steel with low oxygen level in the whole process. Background technique

[0002] IF steel has excellent stamping and forming properties. At present, the smelting of IF steel is mainly produced by the technological process of "converter → alloy fine-tuning station → RH refining furnace → slab continuous casting". In the above-mentioned processes, on the one hand, the two operation sub-units of converter dephosphorization and RH decarburization require molten steel There is a certain amount of oxygen content, and the oxygen content at the end of the converter is too high, which will lead to strong oxidation of the final slag of the converter that inevitably enters the ladle, affecting the castability of molten steel in the continuous casting process; during the RH decarburization period, the oxygen content of molten...

Examples

Embodiment 1

[0027] from figure 1 It can be seen that the smelting method for producing IF steel in a whole process low-oxygen position of the present embodiment, the steps are:

[0028] Step 1: After the smelting of the converter steel, the slag is poured, and 10-15 tons of slag is left in the converter, and 50-100 kg of coke powder is added to remove the oxygen in the slag, and then the slag splashing operation is carried out to protect the furnace;

[0029] The chemical composition requirements of IF steel are: C≤0.0050%, Si≤0.01%, Mn: 0.08~0.25%, P≤0.015%, S≤0.008%, Als: 0.030~0.050%, Ti: 0.030~0.070%;

[0030] The slag composition range of converter slag is: TFe: 12-25%, CaO: 40-60%, SiO 2 : 10~18%, MnO: 2~3%, MgO: 3~6%;

[0031] Composition of coke powder is C≤94%, H2O≤0.020%, S≤0.022%, volatile + ash≤5%, particle size 5-15mm;

[0032] Step 2: Converter charging; the molten iron-scrap linkage ratio mode is adopted, and the amount of molten iron and scrap added is based on the prin...

Embodiment 2

[0064] A kind of smelting method of producing IF steel in the low oxygen position of the whole process of the present embodiment, its steps are:

[0065] Step 1: After the smelting of the last furnace of steel in the converter, the slag is dumped, leaving 13 tons of slag in the converter, adding 75 kg of coke powder to remove the oxygen in the slag, and then performing slag splashing to protect the furnace;

[0066] Step 2: Converter charging: adopt the molten iron-scrap linkage ratio mode, add 298t of molten iron and 33t of scrap steel, of which molten iron Si: 0.28%;

[0067] Step 3: Converter main blowing: Calculated according to “lime addition = 2.14×W[Si]×R×1000 / A”, the total lime addition is 27.1kg / t steel, where W[Si]: 0.28 %, R: 4, W(CaO): 90%, W(SiO 2): 0.35%: tapping amount: 297t, you need to add 8.0t of lime: 4 minutes before blowing: add lime to the converter in 3 batches, keep the lance position at 2.7m, and the oxygen flow rate of the top lance is 63000m 3 / h, ...

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