A method for controlling Ti content in converter tapping of chromium-containing alloy steel

Abstract

The invention provides a technique for controlling the Ti content in converter tapping of chromium-containing alloy steel. A single-slag slag remaining method is adopted for steelmaking in a converter. In the process of converter converting, a special filling system that raw materials such as chromium ore and lime are quantificationally added in batches is adopted, and a bottom blowing mode that N2 is turned into Ar is adopted. According to the technique for controlling the Ti content in converter tapping of the chromium-containing alloy steel, the terminal Cr content of molten steel in the converter is improved, and by comparison, ferrochromium is reduced by 800 kg-1200 kg in the tapping process, so that cost of steelmaking working procedures is lowered. Temperature dropping generated by alloying in the tapping process is reduced by about 25 DEG C-30 DEG C, the time of LF power transmission is reduced by about 8-12 minutes, and LF working procedure energy is saved. The Ti element is prevented from entering the molten steel in the process of adding the ferrochromium, so that the Ti content of the molten steel is effectively lowered, TiN and (TiCN) titanium nitride inclusions formed in the steel due to the high Ti content are reduced, and the quality of the chromium-containing alloy steel is improved.

Description

technical field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a method for controlling Ti content in converter tapping of chromium-containing alloy steel. Background technique

[0002] In recent years, due to the great progress of the steelmaking process, oxide inclusions have been basically controlled in the production of chromium-containing alloy steel, and more and more attention has been paid to the control of nitride inclusions in the process of producing chromium-containing alloy steel. TiN and ( TiCN) is the main nitrided inclusion, and controlling the Ti content in molten steel is the main means to control the nitride.

[0003] Titanium nitride is a hard and brittle inclusion, which can reduce the fatigue life of steel. Among the inclusions of the same level, the hazard of nitride is greater than that of oxide. There is a certain amount of Ti element in the alloy added during the tapping process of the...

Examples

Embodiment 1

[0022] Taking the smelting of SUJ2 type chromium-containing alloy steel as an example, proceed according to the following process steps. The chemical composition of the chromium-containing alloy steel is: C: 0.96, Si: 0.021, Mn: 0.35, P: 0.011, S: 0.001, Al: 0.027, Ca: 0.0004, Cr: 1.46, Ti: 0.0019, Yu The amount is iron.

[0023] 1) Pretreatment of molten iron, the condition of molten iron after pretreatment is as follows:

[0024] C,％

Si,%

Mn,%

P,％

S,％

Ti,%

T,℃

weight, t

4.07

0.59

0.29

0.119

0.001

0.060

1326

100

[0025] Use pretreated molten iron to reduce desulfurization pressure in converter smelting process.

[0026] 2) The converter is smelted by the single slag leaving slag method, and the recovery rate of Cr element is improved by using the saturated Cr in the previous slag, and the recovery rate of Cr can reach more than 45%. In blowing for 1 minute and 30 seconds, 3t of lime, 1t of limestone and 1.2t...

Embodiment 2

[0034] Chromium-containing alloy steel SUJ2, the chemical composition of the chromium-containing alloy steel is: C: 0.98, Si: 0.023, Mn: 0.34, P: 0.009, S: 0.001, Al: 0.028, Ca: 0.0005, Cr: 1.45, Ti: 0.0017, the balance is iron.

[0035] 1) After the pretreatment of molten iron, the condition of molten iron.

[0036] C,％

Si,%

Mn,%

P,％

S,％

Ti,%

T,℃

weight, t

4.58

0.56

0.27

0.118

0.001

0.064

1309

100

[0037] Use pretreated molten iron to reduce desulfurization pressure in converter smelting process.

[0038] 2) The converter is smelted by the single slag leaving slag method, blowing for 1 minute and 30 seconds and concentratedly adding 3.1t of lime and 1.35t of chromium ore for 1 minute and 30 seconds of blowing. Concentrated addition of chromium ore in the early stage can increase the yield of Cr element. Add chrome ore, fluorspar, lime, etc. in batches after blowing for 3 minutes. A total of 4.35t of lime, 4.5...

Embodiment 3

[0047] Chromium-containing alloy steel SUJ2, the chemical composition of the chromium-containing alloy steel is: C: 0.99, Si: 0.021, Mn: 0.36, P: 0.009, S: 0.001, Al: 0.025, Ca: 0.0005, Cr: 1.46, Ti: 0.0017, the balance is iron.

[0048] 1) After the pretreatment of molten iron, the condition of molten iron.

[0049] C,％

Si,%

Mn,%

P,％

S,％

Ti,%

T,℃

weight, t

4.70

0.53

0.30

0128

0.001

0.054

1388

100

[0050] Use pretreated molten iron to reduce desulfurization pressure in converter smelting process.

[0051] 2) The converter is smelted by the single slag leaving slag method, and the slagging material 3t of lime and 1.23t of chrome ore are concentratedly added in 1 minute and 30 seconds of blowing, (the concentration of chromium ore added in the early stage can increase the yield of Cr element) and blowing for 3 minutes Then add chrome ore, fluorspar, lime, etc. in batches, adding 4.01t of lime, 4.1t of chrome ore...

technical field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a method for controlling Ti content in converter tapping of chromium-containing alloy steel. Background technique

[0002] In recent years, due to the great progress of the steelmaking process, oxide inclusions have been basically controlled in the production of chromium-containing alloy steel, and more and more attention has been paid to the control of nitride inclusions in the process of producing chromium-containing alloy steel. TiN and ( TiCN) is the main nitrided inclusion, and controlling the Ti content in molten steel is the main means to control the nitride.

[0003] Titanium nitride is a hard and brittle inclusion, which can reduce the fatigue life of steel. Among the inclusions of the same level, the hazard of nitride is greater than that of oxide. There is a certain amount of Ti element in the alloy added during the tapping process of the...

Examples

Embodiment 1

[0022] Taking the smelting of SUJ2 type chromium-containing alloy steel as an example, proceed according to the following process steps. The chemical composition of the chromium-containing alloy steel is: C: 0.96, Si: 0.021, Mn: 0.35, P: 0.011, S: 0.001, Al: 0.027, Ca: 0.0004, Cr: 1.46, Ti: 0.0019, Yu The amount is iron.

[0023] 1) Pretreatment of molten iron, the condition of molten iron after pretreatment is as follows:

[0024] C,％

Si,%

Mn,%

P,％

S,％

Ti,%

T,℃

weight, t

4.07

0.59

0.29

0.119

0.001

0.060

1326

100

[0025] Use pretreated molten iron to reduce desulfurization pressure in converter smelting process.

[0026] 2) The converter is smelted by the single slag leaving slag method, and the recovery rate of Cr element is improved by using the saturated Cr in the previous slag, and the recovery rate of Cr can reach more than 45%. In blowing for 1 minute and 30 seconds, 3t of lime, 1t of limestone and 1.2t...

Embodiment 2

[0034] Chromium-containing alloy steel SUJ2, the chemical composition of the chromium-containing alloy steel is: C: 0.98, Si: 0.023, Mn: 0.34, P: 0.009, S: 0.001, Al: 0.028, Ca: 0.0005, Cr: 1.45, Ti: 0.0017, the balance is iron.

[0035] 1) After the pretreatment of molten iron, the condition of molten iron.

[0036] C,％

Si,%

Mn,%

P,％

S,％

Ti,%

T,℃

weight, t

4.58

0.56

0.27

0.118

0.001

0.064

1309

100

[0037] Use pretreated molten iron to reduce desulfurization pressure in converter smelting process.

[0038] 2) The converter is smelted by the single slag leaving slag method, blowing for 1 minute and 30 seconds and concentratedly adding 3.1t of lime and 1.35t of chromium ore for 1 minute and 30 seconds of blowing. Concentrated addition of chromium ore in the early stage can increase the yield of Cr element. Add chrome ore, fluorspar, lime, etc. in batches after blowing for 3 minutes. A total of 4.35t of lime, 4.5...

Embodiment 3

[0047] Chromium-containing alloy steel SUJ2, the chemical composition of the chromium-containing alloy steel is: C: 0.99, Si: 0.021, Mn: 0.36, P: 0.009, S: 0.001, Al: 0.025, Ca: 0.0005, Cr: 1.46, Ti: 0.0017, the balance is iron.

[0048] 1) After the pretreatment of molten iron, the condition of molten iron.

[0049] C,％

Si,%

Mn,%

P,％

S,％

Ti,%

T,℃

weight, t

4.70

0.53

0.30

0128

0.001

0.054

1388

100

[0050] Use pretreated molten iron to reduce desulfurization pressure in converter smelting process.

[0051] 2) The converter is smelted by the single slag leaving slag method, and the slagging material 3t of lime and 1.23t of chrome ore are concentratedly added in 1 minute and 30 seconds of blowing, (the concentration of chromium ore added in the early stage can increase the yield of Cr element) and blowing for 3 minutes Then add chrome ore, fluorspar, lime, etc. in batches, adding 4.01t of lime, 4.1t of chrome ore...

Images