CN114959172A - Steelmaking process capable of prolonging service life of slag line of ladle refining furnace - Google Patents
Steelmaking process capable of prolonging service life of slag line of ladle refining furnace Download PDFInfo
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- CN114959172A CN114959172A CN202210509488.5A CN202210509488A CN114959172A CN 114959172 A CN114959172 A CN 114959172A CN 202210509488 A CN202210509488 A CN 202210509488A CN 114959172 A CN114959172 A CN 114959172A
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0075—Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0025—Adding carbon material
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0037—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 by injecting powdered material
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0087—Treatment of slags covering the steel bath, e.g. for separating slag from the molten metal
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C2300/00—Process aspects
- C21C2300/02—Foam creation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
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Abstract
The invention discloses a steelmaking process capable of prolonging the service life of a slag line of a ladle refining furnace, which utilizes carbon dioxide to replace conventional argon as stirring gas, adds a foaming agent before electrode power transmission, and continuously adds the foaming agent in batches after the power transmission, so that foamed slag can be quickly generated, continuously and stably exists, the purposes of quick and stable submerged arc effect and full-process submerged arc of slag are realized, the corrosion of electric arc to the slag line of the ladle refining furnace is obviously reduced, and the service life of the slag line is obviously prolonged.
Description
Technical Field
The invention relates to the technical field of electric arc furnace steelmaking, in particular to a steelmaking process capable of prolonging the service life of a slag line of a ladle refining furnace.
Background
In the steel-making process of the ladle refining furnace, the arc light radiation formed by the exposed arc is strong because the thickness of the slag is less than 150mm when the electrodes are heated, so that the [ arc ] radiation corrosion of a slag line of the ladle refining furnace can be caused, the service life of the slag line of the ladle refining furnace is obviously shortened, and the steel-making cost and the steel-making efficiency are seriously influenced. In order to prolong the service life of the slag line of the ladle refining furnace, a foaming agent is required to be added for slagging in the conventional steel-making process of the ladle refining furnace, so that the slag is rapidly foamed, the volume is increased, and the thickness of the slag is multiplied, thereby realizing the submerged arc effect by utilizing the slag with the increased volume and thickness, reducing the radiation corrosion of electric arc to the slag line and prolonging the service life of the slag line.
Common foaming agents comprise fluorite, calcium carbonate and the like, wherein the fluorite can be quickly melted into slag under a high-temperature condition to form thin slag to cover the surface of liquid steel and release silicon tetrafluoride gas, so that the melted slag on the surface of the liquid steel is quickly foamed to form foamed slag, and electrodes are immersed to realize submerged arc; the calcium carbonate can be decomposed at high temperature to release carbon dioxide and can be reduced into carbon monoxide with excellent foamability by carbon, so that molten slag on the surface of molten steel can be quickly foamed to form foamed slag, and submerged arc is realized; therefore, fluorite and calcium carbonate can play the effects of foaming molten slag, realizing submerged arc and prolonging the service life of the slag line of the ladle refining furnace.
However, in the actual steel-making production process, the fluorite is found to have higher cost, the thickness of the formed foam slag is small, and the generated silicon tetrafluoride gas is toxic; calcium carbonate can achieve a good foaming effect only by being decomposed and reduced, so that the foaming speed is low, the stability is poor, and the duration time is short; in the time period between the addition of the foaming agent and the generation of gas by the foaming agent, the actual thickness of molten slag on the surface of molten steel is very thin, electric arcs generated by electrodes are completely exposed, and the slag lines are seriously corroded, so that the method is a main factor causing the poor effect of prolonging the service life of the slag lines of the ladle refining furnace in the conventional steel-making process of the ladle refining furnace; therefore, how to ensure the quick foaming of the molten steel surface slag and the stability of the foamed slag is the key to prolong the service life of the slag line of the ladle refining furnace.
Disclosure of Invention
The invention aims to overcome the defects of bare electric arc and short service life of a slag line caused by low foaming speed of molten steel surface slag and poor stability of foamed slag after foaming in the prior steelmaking process by adopting an electric arc furnace, and provides a steelmaking process capable of prolonging a ladle refining slag line; the process utilizes carbon dioxide to replace conventional argon as stirring gas, adds the foaming agent before electrode power transmission, and continuously adds the foaming agent in batches after power transmission, so that the foamed slag can be quickly generated, continuously and stably exists, the purposes of quick and stable submerged arc effect and slag full-process submerged arc are realized, the corrosion of electric arc to a slag line of a ladle refining furnace is obviously reduced, and the service life of the slag line is obviously prolonged.
In order to achieve the above object, the present invention provides a steel making process capable of prolonging the service life of a slag line of a ladle refining furnace, which comprises the following steps:
(1) feeding: after carbon dioxide gas is blown into a gas inlet at the bottom of the ladle refining furnace, liquid steel is introduced into the ladle refining furnace;
(2) foaming and slagging: adding a composite foaming agent into the furnace to form foamed slag; the composite foaming agent is a mixture of calcium carbonate and carbon powder with the mass ratio of 1: 0.3-0.8.0.
(3) Electrifying and refining: controlling the thickness of the slag, and refining by heating through an electrode;
(4) discharging: and (5) carrying out temperature measurement and sampling detection, and after meeting the requirements, discharging by a crane ladle to obtain refined molten steel.
According to the steelmaking process capable of prolonging the service life of the slag line of the ladle refining furnace, carbon dioxide is used for replacing conventional and high-value argon as stirring gas and can act together with added calcium carbonate and carbon powder, so that not only is the normal stirring of molten steel ensured, but also carbon dioxide introduced and generated by decomposing the calcium carbonate can partially generate foaming gas carbon monoxide under the action of activated carbon in liquid steel and slag, so that the carbon monoxide is used for promoting the slag to quickly foam to generate foam slag, the optimal foam slag thickness is achieved, the foam slag exists continuously and stably, the quick and stable submerged arc effect is realized, the corrosion effect of electric arc on the slag line of the ladle refining furnace is obviously reduced, and the service life of the slag line is obviously prolonged; meanwhile, the higher the generation speed and the thicker the thickness of the foam slag, the dust CO and CO are contained 2 The smaller the furnace gas amount is, the smaller the decibel of the electric arc noise generated during electrode heating is, and the radiation energy consumption loss of the electric arc is reduced, so that the electric efficiency of the ladle refining furnace is improved, and the effects of saving energy, reducing carbon emission and reducing noise pollution are obvious.
Wherein the introduction amount of the carbon dioxide in the step (2) is the same as that of the conventional argon, and the CO is introduced 2 The stirring work of CO generated by the molten steel and carbon in the slag is increased, the components of the molten steel are uniformly heated, and the effects of floating and removing the non-metallic impurities are remarkable.
Preferably, in the step (2), the mass ratio of calcium carbonate to carbon powder in the composite foaming agent is 1: 0.5-0.7; the optimized mass ratio of calcium carbonate to carbon powder has the advantages of better stability of the foamed slag, better submerged arc effect, less influence on the quality of molten steel, and excessive carbon powder content, and can enter the molten steel to increase the carbon content of the molten steel.
Wherein, preferably, the particle size of the calcium carbonate in the step (2) is 0.5-5 mm; the optimized calcium carbonate has the advantages of high particle size, high decomposition speed and less generated dust, and is more favorable for the rapid formation of slag.
Wherein, preferably, the particle size of the carbon powder in the step (2) is 0.05-1.0 mm; the carbon powder with too small particle size is easy to form dust under the action of air flow, is not beneficial to adding, and can enter molten steel due to incomplete reaction in time to cause the increase of carbon content of the molten steel due to too large particle size.
Wherein, the adding amount of the composite foaming agent in the step (2) can be adjusted according to the thickness of the foam slag, and if the thickness of the foam slag is reduced, the composite foaming agent is added in a proper amount; preferably, the first adding amount of the composite foaming agent is 0.3-0.6 kg per ton of steel; the initial adding amount is too large, the thickness of the foam slag rises sharply, serious potential safety hazards can be caused, safety production is not facilitated, the initial adding amount is too small, the thickness of the foam slag is insufficient, and the submerged arc effect is poor.
Wherein, preferably, in the step (2), the thickness of the formed foam slag is 300-500 mm; the foam slag is too thick, so that the safety production is not facilitated, the consumption of the foaming agent is large, the resource is wasted, the cost is increased, the thickness of the foam slag is insufficient, and the submerged arc effect is poor.
Preferably, in the step (2), the adding time of the composite foaming agent is 10-15s before the electrodes are electrified and heated; the time for adding the foaming agent is too early, the thickness of the slag is controlled to be at the lower limit, otherwise, the safety production is not facilitated, the time for adding the foaming agent is too late, the thickness of the generated foam slag is not enough, the complete submerged arc effect cannot be achieved, and the service life of the slag line can be shortened.
Wherein, preferably, in the step (3), the thickness of the slag is controlled to be 300-500 mm; the foam slag is too thick, so that the safety production is not facilitated, the thickness of the foam slag is insufficient, and the submerged arc effect is poor.
Wherein the refining in the step (3) comprises alloying, desulfurization, deoxidation and the like, impurities and elements which do not meet the requirements in the molten steel can be removed through refining, the quality of the steel is improved, and the method belongs to a conventional process means in a steelmaking process.
Wherein, the temperature measurement in the step (4) is to detect whether the temperature of the molten liquid meets the requirement or not, and prepare for the subsequent vacuum refining process.
The sampling detection in the step (4) is to measure whether the content of impurities and elements in the melt liquid reaches the standard or not by sampling, if so, the refining process is completed, the discharge can be performed, and if not, the composite slagging agent needs to be continuously added, and the refining treatment is continued until the standard is reached.
Compared with the prior art, the invention has the beneficial effects that:
1. the steelmaking process can ensure that the molten slag quickly foams to generate the foam slag, achieves the optimal thickness of the foam slag, and continuously and stably exists, and realizes the quick, stable and comprehensive submerged arc effect, thereby obviously reducing the corrosion effect of electric arc on the slag line of the ladle refining furnace and obviously prolonging the service life of the slag line by 2-3 times.
2. The steelmaking process has no emission of toxic gas of silicon tetrafluoride, can reduce the emission of dust-containing furnace gas (by 40-60%) and carbon dioxide, reduces the arc noise (by less than 40 decibels), and has positive effects of reducing environmental pollution and energy conservation and emission reduction.
3. The steelmaking process can reduce the consumption of the foaming agent, save the argon cost, reduce the steelmaking cost (the cost is reduced by not less than 15 yuan/ton), has simple and reliable process and strong applicability, and can be used for the steelmaking of the industrial ladle refining furnace on a large scale.
Detailed Description
The present invention will be described in further detail with reference to test examples and specific embodiments. It should be understood that the scope of the above-described subject matter is not limited to the following examples, and any techniques implemented based on the disclosure of the present invention are within the scope of the present invention.
Example 1:
refining in a ladle refining furnace to produce national standard No. 20 steel;
equipment: 20 ton ladle refining furnace (slag line used 21 times);
deoxidizing agent: carbon powder, aluminum powder, silicon aluminum calcium, aluminum wire and silicon calcium wire;
desulfurizing agent: calcium oxide;
iron alloy: 75 ferrosilicon, silicomanganese;
foaming agent: calcium carbonate (2 mm) and carbon powder (0.05 mm) in a mass ratio of 1: 0.7;
stirring gas: carbon dioxide;
the specific process steps are as follows:
(1) the refining furnace is in place, 15 tons of molten steel (liquid steel components: 0.09% of carbon, 0.07% of sulfur and 0.009% of phosphorus) is poured into the refining furnace after carbon dioxide stirring gas with the flow rate of 180L/min is introduced into the furnace bottom, and the temperature is 1585 ℃.
(2) Lowering a furnace cover, adding 6.0kg of foaming agent, inserting a three-phase electrode when the thickness of the slag reaches 400mm, inserting the three-phase electrode to the depth of 350mm, and heating for 1min by electrifying (voltage is 220V and current is 8000A);
(3) adding 18kg of calcium oxide into each ton of steel, and after the calcium oxide is completely dissolved (in the dissolving process, adding a foaming agent to keep the thickness of the slag to be more than 350 mm), adding 2.5kg of carbon powder into each ton of steel to perform deoxidation (in the deoxidation process, adding the foaming agent to keep the thickness of the slag to be more than 450 mm), and treating for 10 min;
when the slag begins to turn white, increasing (increasing the flow of the stirring gas to 200L/min) stirring and deoxidizing for 5 min; when the slag turns white and the temperature reaches 1620 ℃, feeding aluminum wires for deep deoxidation for 10min, wherein the aluminum wires are 1m per ton of steel; adding 8Kg of silicomanganese and 2Kg of 75 ferrosilicon into the steel per ton, and after 4min, increasing the gas flow to 240L/min and carrying out strong stirring for 5 min;
sampling and analyzing the components of liquid steel (0.17 percent of carbon, 0.25 percent of silicon, 0.46 percent of manganese, 0.011 percent of phosphorus and 0.035 percent of sulfur), not meeting the requirements, continuing refining and adjusting (after 3kg of carbon powder, 2kg of silicon powder and 2kg of aluminum powder are mixed uniformly, adding a small amount (1 kg) of the mixture for a plurality of times (7 times) into the furnace for deoxidation; supplementing 1kg of 75 ferrosilicon per ton steel and 1kg of high-carbon manganese per ton steel; supplementing 4kg of slag material calcium oxide per ton steel, 2.5kg of carbon powder per ton steel for deoxidation for 3min, and 3.5kg of deep deoxidizer silico-alumino-calcium per ton steel (a small amount of the mixture is added into the furnace, no obvious white flame exists, and the deoxidation effect is the best));
(4) keeping the temperature at 1640 ℃ for 5min, sampling again, detecting liquid steel components (0.19 carbon, 0.32 silicon, 0.016 phosphorus, 0.023 sulfur, 0.11 nickel, 0.22 chromium and 0.16 copper) and meeting the requirements; when the temperature of the liquid steel reaches 1655 ℃, power is cut off, and a silicon-calcium line is fed for 2 m/ton steel; and (5) the crane ladle is out of the station.
The data in the whole process are recorded as follows:
| recording items | Time (S) required for the slag thickness to reach 350mm | Amount of foaming agent (KG/ton) | Maximum arc volume (decibel) | Depth of slag line corrosion (mm) | Minimum thickness (mm) of slag in refining process |
| Record the results | 6.3 | 5.4 | 35 | 2.8 | 380 |
Example 2
Refining in ladle refining furnace to produce 50Mn 18 Cr 5 Non-magnetic steel;
equipment: 20 ton ladle refining furnace (slag line used 45 times);
deoxidizing agent: carbon powder, aluminum powder, silicon aluminum calcium, aluminum wire and silicon calcium wire;
desulfurizing agent: calcium oxide;
iron alloy: 75 ferrosilicon, manganese metal, low-carbon manganese, high-carbon manganese, medium-carbon chromium and ferrovanadium (vanadium 50);
foaming agent: calcium carbonate (0.5 mm) and carbon powder (0.5 mm) in a mass ratio of 1: 0.6;
stirring gas: carbon dioxide;
the specific process steps are as follows:
(1) the refining furnace is in place, 15 tons of molten steel (0.40 percent of carbon, 0.07 percent of sulfur and 0.005 percent of phosphorus) is poured into the refining furnace after carbon dioxide stirring gas with the flow rate of 100L/min is introduced into the furnace bottom, and 60kg of metal manganese and 6lkg tons of medium carbon chromium are added into the refining furnace; the temperature is 1580 ℃;
(2) lowering a furnace cover, adding 8.0kg of foaming agent, inserting a three-phase electrode when the thickness of the slag reaches 400mm, inserting the three-phase electrode to the depth of 350mm, and heating for 1min by electrifying (voltage is 220V and current is 8000A);
(3) adding 18kg of calcium oxide into each ton of steel, and after the calcium oxide is completely dissolved (in the dissolving process, adding a foaming agent to keep the thickness of the slag to be more than 350 mm), adding 2.5kg of carbon powder into each ton of steel to perform deoxidation (in the deoxidation process, adding the foaming agent to keep the thickness of the slag to be more than 350 mm), and treating for 10 min;
when the slag begins to turn white, increasing (increasing the flow of the stirring gas to 200L/min) stirring and deoxidizing for 5 min; when the slag turns white and the temperature reaches 1620 ℃, feeding aluminum wires for deep deoxidation for 10min, wherein the aluminum wires are 1m per ton of steel; adding 40kg of high-carbon manganese per ton steel, 45kg of low-carbon manganese per ton steel, 70kg of metal manganese per ton steel and 2kg of 75 silicon iron per ton steel, and after 6min, increasing the gas flow to 220L/min and carrying out strong stirring for 5 min;
adding 8Kg of silicomanganese and 2Kg of 75 silicon iron into each ton of steel, increasing the gas flow to 240L/min after 4min, and carrying out strong stirring for 5 min;
sampling and analyzing the components of liquid steel (0.48 percent of carbon, 0.35 percent of silicon, 17.46 percent of manganese, 0.021 percent of phosphorus, 0.025 percent of sulfur and 3.50 percent of chromium), refining and adjusting again (after 3kg of carbon powder, 2kg of silicon powder and 2kg of aluminum powder are mixed uniformly, adding a small amount (1 kg) of carbon and chromium into the furnace for deoxidation in multiple batches (7 times), supplementing 5kg of medium carbon and chromium/ton steel, 1kg of 75 ferrosilicon/ton steel and 10kg of low carbon and manganese/ton steel, supplementing 4kg of slag material calcium oxide/ton steel, 2.5kg of carbon powder/ton steel for deoxidation for 3min, and adding a small amount of deep silicon aluminum and calcium into the furnace without obvious white flame and with the best deoxidation effect)); adding ferrovanadium 2 kg/ton steel;
(4) keeping the temperature at 1640 ℃ for 5min, sampling again, detecting liquid steel components (0.49% of carbon, 0.52% of silicon, 0.024% of manganese, 18.2% of phosphorus, 0.008% of sulfur, 0.09% of vanadium, 3.92% of chromium and 0.045% of aluminum), and meeting the requirements; when the temperature of the liquid steel reaches 1630 ℃, power is cut off, and a silicon-calcium line is fed for 2 m/ton steel; and (5) the crane ladle is out of the station.
The data in the whole process are recorded as follows:
| recording items | Time (S) required for the slag thickness to reach 350mm | Amount of foaming agent (KG/ton) | Maximum arc volume (decibel) | Depth of slag line corrosion (mm) | Minimum thickness (mm) of slag in refining process |
| Record the results | 5.8 | 5.3 | 36 | 3.4 | 320 |
Example 3
Refining production of Cr in ladle refining furnace 8 Mo 2 SiV cold work die steel;
equipment: 20 ton ladle refining furnace (slag line used 53 times);
deoxidizing agent: carbon powder, aluminum powder, silicon aluminum calcium, aluminum wire and silicon calcium wire;
desulfurizing agent: calcium oxide;
iron alloy: 75 ferrosilicon, high-carbon manganese, high-carbon ferrochrome, ferromolybdenum (60) and ferrovanadium (vanadium 50);
foaming agent: calcium carbonate (5 mm) and carbon powder (1.0 mm) in a mass ratio of 1: 0.5;
stirring gas: carbon dioxide;
the specific process steps are as follows:
(1) the refining furnace is in place, 15 tons of molten steel (0.80 percent of carbon, 0.07 percent of sulfur, 0.009 percent of phosphorus and 0.6 percent of molybdenum) is poured into the refining furnace after carbon dioxide stirring gas with the flow rate of 100L/min is introduced into the furnace bottom, and 40kg of high-carbon ferrochrome and 20kg of ferromolybdenum are added per ton of steel at the same time; the temperature is 1580 ℃;
(2) lowering a furnace cover, adding 4.0kg of foaming agent, inserting a three-phase electrode when the thickness of the slag reaches 400mm, inserting the three-phase electrode to the depth of 350mm, and heating for 1min by electrifying (voltage is 220V and current is 8000A);
(3) adding 18kg of calcium oxide into each ton of steel, and after the calcium oxide is completely dissolved (in the dissolving process, adding a foaming agent to keep the thickness of the slag to be more than 300 mm), adding 2.5kg of carbon powder into each ton of steel to perform deoxidation (in the deoxidation process, adding the foaming agent to keep the thickness of the slag to be more than 300 mm), and treating for 10 min;
when the slag begins to turn white, increasing the flow of the stirring gas to 240L/min, stirring and deoxidizing for 5 min; when the slag turns white and the temperature reaches 1620 ℃, feeding aluminum wires for deep deoxidation for 5min, wherein the aluminum wires are 1m per ton of steel; adding 100kg of high-carbon chromium per ton steel, 6kg of high-carbon manganese per ton steel and 10kg of 75 silicon iron per ton steel, and after 6min, increasing the gas flow to 260L/min and carrying out strong stirring for 5 min;
adding 10kg of high-carbon chromium per ton steel, 6kg of high-carbon manganese per ton steel and 10kg of 75 silicon iron per ton steel, and strongly stirring for 5min after 4min at a gas flow rate of 260L/min;
sampling and analyzing the components of liquid steel (0.98 percent of carbon, 0.75 percent of silicon, 0.35 percent of manganese, 0.021 percent of phosphorus, 0.035 percent of sulfur, 8.28 percent of chromium, 1.75 percent of molybdenum and 0.04 percent of vanadium), refining and adjusting again (after 3kg of carbon powder, 2kg of silicon powder and 2kg of aluminum powder are mixed uniformly, adding a small amount (1 kg) of carbon powder, 2kg of silicon powder and 2kg of aluminum powder into the furnace for deoxidation for a plurality of times (7 times), supplementing 4kg of high-carbon chromium/ton steel, 2kg of 75 ferrosilicon/ton steel and 1kg of high-carbon manganese/ton steel, supplementing 4kg of slag material calcium oxide/ton steel, deoxidizing for 3min by 2.5kg of carbon powder/ton steel, and adding 3.5kg of deep carbon powder deoxidizer silico-calcium/ton steel (a small amount of silicon-aluminum-calcium is not added into the furnace, has obvious white flame and has the best deoxidation effect));
(4) keeping the temperature at 1610 ℃ for 5min, sampling again, detecting the liquid steel components (1.03 percent of carbon, 0.89 percent of silicon, 0.42 percent of manganese, 0.026 percent of phosphorus, 0.023 percent of sulfur, 0.41 percent of nickel, 8.82 percent of chromium, 0.11 percent of vanadium and 0.26 percent of copper) and meeting the requirements; when the liquid steel temperature reaches 1635 ℃, 5m i n is kept, power is cut off, and 2 m/ton of steel is fed with a silicon-calcium line; and (5) the crane ladle is out of the station.
The data of the whole process are recorded as follows:
| recording items | Time (S) required for the slag thickness to reach 350mm | Amount of foaming agent (KG/ton) | Maximum arc volume (decibel) | Depth of slag line corrosion (mm) | Minimum thickness (mm) of slag in refining process |
| Record the results | 6.5 | 6.3 | 38 | 3.3 | 280 |
Comparative example 1
Refining in a ladle refining furnace to produce national standard No. 20 steel;
equipment: 20 ton ladle refining furnace (slag line has been used 22 times);
deoxidizing agent: carbon powder, aluminum powder, silicon aluminum calcium, aluminum wire and silicon calcium wire;
desulfurizing agent: calcium oxide;
iron alloy: 75 ferrosilicon, silicomanganese;
foaming agent: fluorite;
stirring gas: carbon dioxide;
the specific process steps are as follows:
(1) the refining furnace is in place, 15 tons of molten steel (liquid steel components: 0.09% of carbon, 0.07% of sulfur and 0.009% of phosphorus) is poured into the refining furnace after carbon dioxide stirring gas with the flow rate of 180L/min is introduced into the furnace bottom, and the temperature is 1585 ℃.
(2) When the electrode is electrified, 20.0kg fluorite is added to produce thin slag (43 mm), and the electrode is electrified (with voltage of 220V and current of 8000A) by inserting a three-phase electrode to heat for 1 min;
(3) adding 18kg of calcium oxide into each ton of steel, and treating for 10min when the calcium oxide is completely dissolved (in the whole process, the thickness of slag is about 150mm, adding 2.5kg of carbon powder into each ton of steel for deoxidation, and in the deoxidation process, the thickness of slag is about 150 m;
when the slag begins to turn white, increasing (increasing the flow of the stirring gas to 200L/min) stirring and deoxidizing for 5 min; when the slag turns white and the temperature reaches 1620 ℃, feeding aluminum wires for deep deoxidation for 10min, wherein the aluminum wires are 1m per ton of steel; adding 8Kg of silicomanganese and 2Kg of 75 ferrosilicon into the steel per ton, and after 4min, increasing the gas flow to 240L/min and carrying out strong stirring for 5 min;
sampling and analyzing the components of liquid steel (0.17 percent of carbon, 0.25 percent of silicon, 0.46 percent of manganese, 0.011 percent of phosphorus and 0.035 percent of sulfur), not meeting the requirements, refining and adjusting again (after 3kg of carbon powder, 2kg of silicon powder and 2kg of aluminum powder are mixed uniformly, adding a small amount (1 kg) of the mixture for a plurality of times (7 times) into the furnace for deoxidation; supplementing 1kg of 75 ferrosilicon per ton steel and 1kg of high-carbon manganese per ton steel; supplementing 4kg of slag material calcium oxide per ton steel, 2.5kg of carbon powder per ton steel for deoxidation for 3min, and 3.5kg of deep deoxidizer silico-alumino-calcium per ton steel (a small amount of the mixture is added into the furnace, no obvious white flame exists, and the deoxidation effect is the best));
(4) keeping the temperature at 1640 ℃ for 5min, sampling again, detecting liquid steel components (0.19 carbon, 0.32 silicon, 0.016 phosphorus, 0.023 sulfur, 0.11 nickel, 0.22 chromium and 0.16 copper) and meeting the requirements; when the temperature of the liquid steel reaches 1655 ℃, power is cut off, and a silicon-calcium line is fed for 2 m/ton steel; and (5) the crane ladle is out of the station.
The data of the whole process are recorded as follows:
| recording items | Time (S) required for the slag thickness to reach 350mm | Fluorite dosage (KG/ton) | Maximum arc volume (decibel) | Depth of slag line corrosion (mm) | Minimum thickness (mm) of slag in refining process |
| Record the results | Cannot reach the thickness | 8.2 | 84 | 15 | 60 |
Comparing with example 1, it can be seen that: adopt traditional fluorite slagging-off, because fluorite slagging-off effect is poor, poor stability, lead to the thickness of foam sediment little, can not realize lasting, stable submerged arc effect to lead to in the steelmaking process, the noise is big, show the increase to the depth of corrosion of slag line.
Comparative example 2
Refining in a ladle refining furnace to produce national standard No. 20 steel;
equipment: 20 ton ladle refining furnace (slag line used 23 times);
deoxidizing agent: carbon powder, aluminum powder, silicon aluminum calcium, aluminum wire and silicon calcium wire;
desulfurizing agent: calcium oxide;
iron alloy: 75 ferrosilicon, silicomanganese;
foaming agent: calcium carbonate and carbon powder with the mass ratio of 1: 0.7;
stirring gas: argon gas;
the specific process steps are as follows:
(1) the refining furnace is in place, argon stirring gas with the flow rate of 180L/min is introduced into the furnace bottom, and 15 tons of molten steel (the components of the molten steel are 0.09 percent of carbon, 0.07 percent of sulfur and 0.009 percent of phosphorus) are poured into the refining furnace at the temperature of 1585 ℃.
(2) Lowering a furnace cover, adding 6.0kg of foaming agent, inserting a three-phase electrode when the thickness of the slag reaches 400mm, inserting the three-phase electrode to the depth of 350mm, and heating for 1min by electrifying (voltage is 220V and current is 8000A);
(3) adding 18kg of calcium oxide into each ton of steel, and after the calcium oxide is completely dissolved (in the dissolving process, adding a foaming agent to keep the thickness of the slag to be more than 250 mm), adding 2.5kg of carbon powder into each ton of steel to perform deoxidation (in the deoxidation process, adding the foaming agent to keep the thickness of the slag to be more than 350 mm), and treating for 10 min;
when the slag begins to turn white, increasing (increasing the flow of the stirring gas to 200L/min) stirring and deoxidizing for 5 min; when the slag turns white and the temperature reaches 1620 ℃, feeding aluminum wires for deep deoxidation for 10min, wherein the aluminum wires are 1m per ton of steel; adding 8Kg of silicomanganese and 2Kg of 75 ferrosilicon into the steel per ton, and after 4min, increasing the gas flow to 240L/min and carrying out strong stirring for 5 min;
sampling and analyzing the components of liquid steel (0.17% of carbon, 0.25% of silicon, 0.46% of manganese, 0.011% of phosphorus and 0.035% of sulfur), not meeting the requirements, refining and adjusting again (after 3kg of carbon powder, 2kg of silicon powder and 2kg of aluminum powder are mixed, adding a small amount (1 kg) of the mixture in a furnace for multiple batches (7 times), deoxidizing, supplementing 1kg of 75 silicon iron/ton steel, 1kg of high-carbon manganese/ton steel, supplementing 4kg of slag material calcium oxide/ton steel, deoxidizing for 3min by 2.5kg of carbon powder/ton steel, and adding 3.5kg of deep deoxidizer silicon aluminum calcium/ton steel (a small amount of the mixture is added in the furnace, no obvious white flame exists, and the deoxidizing effect is best));
(4) keeping the temperature at 1640 ℃ for 10min, sampling again, detecting the liquid steel components (0.19 carbon, 0.32 silicon, 0.016 phosphorus, 0.023 sulfur, 0.11 nickel, 0.22 chromium and 0.16 copper) and meeting the requirements; when the temperature of the liquid steel reaches 1655 ℃, power is cut off, and a silicon-calcium line is fed for 2 m/ton steel; and (5) the crane ladle is out of the station.
The data of the whole process are recorded as follows:
| recording items | Time (S) required for the slag thickness to reach 350mm | Amount of foaming agent (KG/ton) | Maximum arc volume (decibel) | Depth of slag line corrosion (mm) | Minimum thickness (mm) of slag in refining process |
| Record the results | 7.8 | 6.5 | 37 | 4.8 | 200 |
Comparing with example 1, it can be seen that: argon is adopted to replace carbon dioxide as stirring gas, and carbon monoxide can not be continuously generated under the action of added carbon powder, so that the stability of the thickness of the foamed slag is reduced, the generation speed is reduced, the consumption of a foaming agent is increased, and the corrosion depth of a slag line is obviously increased.
Comparative example 3
Refining in a ladle refining furnace to produce national standard No. 20 steel;
equipment: 20 ton ladle refining furnace (slag line has been used 24 times);
deoxidizing agent: carbon powder, aluminum powder, silicon aluminum calcium, aluminum wire and silicon calcium wire;
desulfurizing agent: calcium oxide;
iron alloy: 75 ferrosilicon, silicomanganese;
foaming agent: calcium carbonate;
stirring gas: carbon dioxide;
the specific process steps are as follows:
(1) the refining furnace is in place, 15 tons of molten steel (liquid steel components: 0.09% of carbon, 0.07% of sulfur and 0.009% of phosphorus) is poured into the refining furnace after carbon dioxide stirring gas with the flow rate of 180L/min is introduced into the furnace bottom, and the temperature is 1585 ℃.
(2) Lowering a furnace cover, adding 6.0kg of foaming agent, inserting a three-phase electrode when the thickness of the slag reaches 400mm, inserting the three-phase electrode to the depth of 350mm, and heating for 1min by electrifying (voltage is 220V and current is 8000A);
(3) adding 18kg of calcium oxide into each ton of steel, and after the calcium oxide is completely dissolved (in the dissolving process, adding a foaming agent to keep the thickness of the slag to be more than 250 mm), adding 2.5kg of carbon powder into each ton of steel to perform deoxidation (in the deoxidation process, adding the foaming agent to keep the thickness of the slag to be more than 350 mm), and treating for 10 min;
when the slag begins to turn white, increasing (increasing the flow of the stirring gas to 200L/min) stirring and deoxidizing for 5 min; when the slag turns white and the temperature reaches 1620 ℃, feeding aluminum wires for deep deoxidation for 10min, wherein the aluminum wires are 1m per ton of steel; adding 8Kg of silicomanganese and 2Kg of 75 ferrosilicon into the steel per ton, and after 4min, increasing the gas flow to 240L/min and carrying out strong stirring for 5 min;
sampling and analyzing the components of liquid steel (0.17 percent of carbon, 0.25 percent of silicon, 0.46 percent of manganese, 0.011 percent of phosphorus and 0.035 percent of sulfur), not meeting the requirements, refining and adjusting again (after 3kg of carbon powder, 2kg of silicon powder and 2kg of aluminum powder are mixed uniformly, adding a small amount (1 kg) of the mixture for a plurality of times (7 times) into the furnace for deoxidation; supplementing 1kg of 75 ferrosilicon per ton steel and 1kg of high-carbon manganese per ton steel; supplementing 4kg of slag material calcium oxide per ton steel, 2.5kg of carbon powder per ton steel for deoxidation for 3min, and 3.5kg of deep deoxidizer silico-alumino-calcium per ton steel (a small amount of the mixture is added into the furnace, no obvious white flame exists, and the deoxidation effect is the best));
(4) keeping the temperature at 1640 ℃ for 5min, sampling again, detecting liquid steel components (0.19 carbon, 0.32 silicon, 0.016 phosphorus, 0.023 sulfur, 0.11 nickel, 0.22 chromium and 0.16 copper) and meeting the requirements; when the temperature of the liquid steel reaches 1655 ℃, power is cut off, and a silicon-calcium line is fed for 2 m/ton steel; and (5) the crane ladle is out of the station.
The data of the whole process are recorded as follows:
| recording items | Time (S) required for the slag thickness to reach 350mm | Amount of foaming agent (KG/ton) | Maximum arc volume (decibel) | Depth of slag line corrosion (mm) | Minimum thickness (mm) of slag in refining process |
| Record the results | 10.7 | 7.8 | 43 | 5.5 | 130 |
Comparing with example 1, it can be seen that: the carbon powder is not added, and the carbon monoxide can not be continuously generated in a large amount by reaction with the stirring gas carbon dioxide, so that the foaming speed of the slag is obviously reduced, more foaming agents are required to be added to ensure the thickness of the slag, and meanwhile, the stability of the thickness of the slag is reduced, and the corrosion depth of the slag line is obviously increased.
Comparative example 4:
refining in a ladle refining furnace to produce national standard No. 20 steel;
equipment: 20 ton ladle refining furnace (slag line has been used 25 times);
deoxidizing agent: carbon powder, aluminum powder, silicon aluminum calcium, aluminum wire and silicon calcium wire;
desulfurizing agent: calcium oxide;
iron alloy: 75 ferrosilicon, silicomanganese;
foaming agent: calcium carbonate and carbon powder with the mass ratio of 1: 0.2;
stirring gas: carbon dioxide;
the specific process steps are as follows:
(1) the refining furnace is in place, 15 tons of molten steel (liquid steel components: 0.09% of carbon, 0.07% of sulfur and 0.009% of phosphorus) is poured into the refining furnace after carbon dioxide stirring gas with the flow rate of 180L/min is introduced into the furnace bottom, and the temperature is 1585 ℃.
(2) Lowering a furnace cover, adding 6.0kg of foaming agent, inserting a three-phase electrode when the thickness of the slag reaches 400mm, inserting the three-phase electrode to the depth of 350mm, and heating for 1min by electrifying (voltage is 220V and current is 8000A);
(3) adding 18kg of calcium oxide into each ton of steel, and after the calcium oxide is completely dissolved (in the dissolving process, adding a foaming agent to keep the thickness of the slag to be more than 250 mm), adding 2.5kg of carbon powder into each ton of steel to perform deoxidation (in the deoxidation process, adding the foaming agent to keep the thickness of the slag to be more than 350 mm), and treating for 10 min;
when the slag begins to turn white, increasing (increasing the flow of the stirring gas to 200L/min) stirring and deoxidizing for 5 min; when the slag turns white and the temperature reaches 1620 ℃, feeding aluminum wires for deep deoxidation for 5min, wherein the aluminum wires are 1m per ton of steel; adding 8Kg of silicomanganese and 2Kg of 75 ferrosilicon into the steel per ton, and after 4min, increasing the gas flow to 240L/min and carrying out strong stirring for 5 min;
sampling and analyzing the components of liquid steel (0.17 percent of carbon, 0.25 percent of silicon, 0.46 percent of manganese, 0.011 percent of phosphorus and 0.035 percent of sulfur), not meeting the requirements, refining and adjusting again (after 3kg of carbon powder, 2kg of silicon powder and 2kg of aluminum powder are mixed uniformly, adding a small amount (1 kg) of the mixture for a plurality of times (7 times) into the furnace for deoxidation; supplementing 1kg of 75 ferrosilicon per ton steel and 1kg of high-carbon manganese per ton steel; supplementing 4kg of slag material calcium oxide per ton steel, 2.5kg of carbon powder per ton steel for deoxidation for 3min, and 3.5kg of deep deoxidizer silico-alumino-calcium per ton steel (a small amount of the mixture is added into the furnace, no obvious white flame exists, and the deoxidation effect is the best));
(4) keeping the temperature at 1640 ℃ for 5min, sampling again, detecting the liquid steel components (0.19 carbon, 0.32 silicon, 0.016 phosphorus, 0.023 sulfur, 0.11 nickel, 0.22 chromium and 0.16 copper) and meeting the requirements; when the temperature of the liquid steel reaches 1655 ℃, power is cut off, and a silicon-calcium line is fed for 2 m/ton steel; and (5) the crane ladle is out of the station.
The data of the whole process are recorded as follows:
| recording items | Time (S) required for the slag thickness to reach 350mm | Average amount of foaming agent (KG/ton) | Maximum arc volume (decibel) | Depth of slag line corrosion (mm) | Minimum thickness (mm) of slag in refining process |
| Record the results | 7.6 | 6.5 | 43 | 4.6 | 220 |
Comparing with example 1, it can be seen that: the carbon powder proportion is too small, the carbon monoxide amount generated continuously by the reaction of the carbon powder and the stirring gas carbon dioxide is small, so that the foaming speed of the slag is reduced, more foaming agents are required to be added to ensure the thickness of the slag, and meanwhile, the stability of the thickness of the slag is reduced, and the corrosion depth of a slag line is obviously increased.
Claims (8)
1. A steel-making process capable of prolonging the service life of a slag line of a ladle refining furnace is characterized by comprising the following steps:
(1) feeding: after carbon dioxide gas is blown into a gas inlet at the bottom of the ladle refining furnace, liquid steel is introduced into the ladle refining furnace;
(2) foam slag making: adding a composite foaming agent into the furnace to form foamed slag; the composite foaming agent is a mixture of calcium carbonate and carbon powder in a mass ratio of 1: 0.3-0.8;
(3) electrifying and refining: controlling the thickness of the slag, and refining by heating through an electrode;
(4) discharging: and (5) carrying out temperature measurement and sampling detection, and after meeting the requirements, discharging by a crane ladle to obtain refined molten steel.
2. The steelmaking process according to claim 1, wherein in the step (2), the mass ratio of calcium carbonate to carbon powder in the composite foaming agent is 1: 0.5-0.7.
3. The steelmaking process according to claim 1, wherein in step (2), the calcium carbonate has a particle size of 0.5 to 5 mm.
4. The steelmaking process according to claim 1, wherein in step (2), the carbon powder has a particle size of 0.05 to 1.0 mm.
5. The steelmaking process according to claim 1, wherein in the step (2), the first adding amount of the composite foaming agent is 0.3-0.6 kg/ton of steel.
6. The steelmaking process according to claim 1, wherein in the step (2), the adding time of the composite foaming agent is 10-15s before the electrodes are electrified and heated.
7. The steelmaking process as claimed in claim 1, wherein in step (2), the foamed slag is formed to a thickness of 300-500 mm.
8. The steelmaking process as claimed in claim 1, in which in step (3), the thickness of the slag during refining is controlled to be 300-500 mm.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115537498A (en) * | 2022-09-30 | 2022-12-30 | 安徽工业大学 | Method for quickly producing white slag by using silicon-aluminum-containing killed steel |
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