CN115976297A - Method for rapidly slagging high-surface-quality stainless steel by short-process smelting - Google Patents
Method for rapidly slagging high-surface-quality stainless steel by short-process smelting Download PDFInfo
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Abstract
The invention belongs to the technical field of steel smelting, and relates to a short-process high-surface-quality stainless steel smelting rapid slagging method, which comprises the following steps of AOD-LTS or LT-continuous casting, wherein in the LTS or LT smelting process, 2-4 kg of rapid slagging agent per ton of steel is added, the alkalinity of furnace slag is adjusted to be 1.4-1.6, alloy fine-tuning components are added according to the analysis result of the components of molten steel, the total amount of the alloy is less than or equal to 500kg, the total stirring flow of double-hole bottom blowing gas of a steel ladle is 5-7 NL/min per ton of steel, and the stirring time is controlled to be 2-10 min. According to the rapid slagging method, the temperature drop in the smelting process is small, the uniform and stable slag system is rapidly formed under the short flow and the fast rhythm of stainless steel without the treatment of an LF furnace, and more effective refining time is remained for removing impurities.
Description
Technical Field
The invention belongs to the technical field of steel smelting, and particularly relates to a method for quickly slagging high-surface-quality stainless steel through short-process smelting.
Background
With the development of stainless steel smelting technology, the traditional long-flow refining process (AOD-LTS-VOD-LF-CCM or AOD-LTS-LF-CCM) is difficult to adapt to the fast-paced production requirement under the high drawing speed of continuous casting, and is gradually replaced by a short-flow process (AOD-LTS-CCM or AOD-LT-CCM). In addition, in order to ensure the process temperature and reduce the cost of raw materials, the AOD usually adopts high-carbon high-silicon raw materials, the AOD blowing time is prolonged, and the refining time after AOD tapping is compressed to a certain extent. For the reasons, higher requirements are put forward on the slag control in the refining process, and the special requirements of products on cleanliness and cold plate surface quality are met while the rapid slagging is ensured and the process temperature drop is small. Lime, fluorite and the like are mainly added in the refining process of the conventional process for slag adjustment, the slag melting is slow, the temperature drop is large, longer-time stirring or heating for slag melting is needed, the influence of hard impurities on the surface of a cold plate cannot be avoided, and the requirements cannot be met.
The Chinese patent with publication number CN105567907A CN111733308A proposes a control method of stainless steel plastic inclusions and a slag-forming method of slag in a smelting process, but silica and quartz sand added in the slag-forming process have a melting point as high as 1750 ℃, can be completely melted by means of temperature rise of an LF furnace and large-flow stirring, and are difficult to meet fast-speed production, and oxygen enrichment and serious corrosion to steel ladle refractory are caused when the alkalinity of the slag is low. By adopting the technical method provided by CN111733308A, the inclusion component is SiO 2 11.1％,Al 2 O 3 12.2％，MnO 37.9％，TiO 2 13.0％，Cr 2 O 3 25.9% and a large amount of MnO. Cr 2 O 3 The spinel hard inclusions have adverse effects on the surface of the cold plate.
Chinese patents with publication numbers CN114369700A, CN1201833A and CN102382947A all relate to low-alkalinity synthetic slag, but the influence of molten steel components, slag components before slag adjustment, the melting point of the synthetic slag, fluidity after slag melting, the particle structure of the synthetic slag and other factors on molten steel cleanliness, process temperature drop, slag melting effect and steel ladle refractory corrosion and economic cost are not comprehensively considered. Moreover, the patents only disclose the components of the synthetic slag, and do not disclose the preparation method of the synthetic slag.
How to solve the problems of quick slagging and cleanliness control under the short flow and the quick rhythm of stainless steel becomes a development target in the field.
Disclosure of Invention
The invention aims to provide a method for rapidly slagging high-surface-quality stainless steel by short-process smelting aiming at the defects of the prior art.
Specifically, the short-process high-surface-quality stainless steel smelting rapid slagging method comprises the following process flows of AOD-LTS or LT-continuous casting, wherein in the LTS or LT smelting process, 2-4 kg of rapid slagging agent per ton of steel is added, the alkalinity of furnace slag is adjusted to 1.4-1.6, alloy fine adjustment components are added according to the analysis result of the components of the steel liquid, the total amount of the alloy is less than or equal to 500kg, the total stirring flow of gas blown from the bottom of double holes of a steel ladle is 5-7 NL/min per ton of steel, and the stirring time is controlled to be 2-10 min.
According to the method for rapidly forming the slag by smelting the stainless steel with high surface quality in the short process, the rapid slag forming agent comprises the following components in percentage by weight: 22 to 29 percent of CaO and SiO 2 55-60%, mgO 10-20%, si-Ca or Si-Fe alloy powder 1-5%.
According to the method for rapidly forming the slag by smelting the stainless steel with high surface quality in the short process, the impurities in the rapid slag forming agent comprise the following components in percentage by weight: al (aluminum) 2 O 3 Less than or equal to 5 percent, less than or equal to 1 percent of the total of the iron, manganese and chromium oxides, less than or equal to 0.02 percent of P, less than or equal to 0.02 percent of S and less than or equal to 0.5 percent of water。
According to the method for rapidly forming the slag by smelting the stainless steel with high surface quality in the short process, the melting point of the rapid slag forming agent is 1250-1390 ℃, and the melting speed is less than 150s at 1400 ℃.
The method for smelting the stainless steel with high surface quality by the short process to form the slag rapidly, the preparation method of the rapid slagging agent comprises the following steps:
(1) Mixing, crushing and grinding the slag materials into powder of 50-200 meshes according to the proportion;
(2) Mechanically mixing the powder with calcium silicate powder or ferrosilicon powder uniformly to obtain a mixture;
(3) Adding a binder, mechanically extruding and forming to prepare particles with the particle size of 5-30 mm, and drying.
According to the method for rapidly slagging the short-process smelting high-surface-quality stainless steel, the mixture comprises the following components in percentage by weight: 30-40% of light-burned dolomite, 0-10% of light-burned magnesium balls, 0-5% of lime, 45-54% of quartz sand and 1-5% of silicon calcium powder and/or silicon iron powder.
The method for rapidly slagging the short-process smelting high-surface-quality stainless steel comprises the following steps: 80-99% of diopside, 0-5% of light-burned magnesium balls, 0-5% of lime, 0-5% of quartz sand and 1-5% of silicon calcium powder and/or silicon iron powder.
The method for rapidly slagging the short-process smelted stainless steel with high surface quality comprises the following steps of 1-4% by weight of AOD steel mixing component w (C) and 0.1-3.5% by weight of w (Si); w (C) is not less than 0.02% after the blowing; the AOD reduction time is 8-10 min, and w (S) is less than or equal to 0.030 percent after reduction.
According to the method for rapidly slagging the short-process smelting high-surface-quality stainless steel, the AOD adjusting period is 5-10 min, and the weight percentage of the components w (S) of the tapping molten steel is controlled to be less than or equal to 0.0050 percent, w (Al) is controlled to be less than or equal to 0.0080 percent, and w (Ti) is controlled to be less than or equal to 0.0080 percent.
According to the method for rapidly slagging the high-surface-quality stainless steel by short-process smelting, before AOD (argon oxygen decarburization) tapping or LTS (low temperature decarburization) is put into a station and slag is removed until the thickness of the slag is 50-150 mm or the slag amount of 5-20 kg of steel per ton is obtained, and the temperature of molten steel after slag removal is more than or equal to 1600 ℃.
The technical scheme of the invention has the following beneficial effects:
(1) According to the rapid slagging method, the temperature drop in the smelting process is small, the uniform and stable slag system is rapidly formed under the short flow and fast rhythm of stainless steel without the treatment of an LF (ladle furnace), and more effective refining time is remained for removing impurities;
(2) The rapid slagging agent adopted by the invention can directly use raw ores as raw materials, has low preparation cost and strong raw material adaptability, does not need high-temperature sintering and premelting, and does not influence the melting speed;
(3) The rapid slagging agent adopted by the invention can be used for replacing slagging agents such as lime, fluorite, silica and the like, so that the smelting cost is reduced;
(4) The rapid slagging agent adopted by the invention is easy to stably control the components and alkalinity of the slag in the steel smelting process, can reduce oxygen increase or sulfur increase in the slagging process, has a certain diffusion deoxidation effect, and can effectively avoid the influence of hard inclusion in steel smelting on the surface quality of a cold plate.
Drawings
Various additional advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention.
FIG. 1 is a schematic view of the conventional slag melting principle;
FIG. 2 is a schematic view of the melting principle of the rapid slagging agent of the present invention.
Detailed Description
The present invention will be described in detail with reference to the following embodiments in order to fully understand the objects, features and effects of the invention. The process of the present invention employs conventional methods or apparatus in the art, except as described below. The following noun terms unless otherwise indicated, all have the meanings commonly understood by those skilled in the art.
When a range of values is disclosed herein, the range is considered to be continuous and includes both the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. Further, when multiple range-describing features or characteristics are provided, the ranges may be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. In the present invention, "%" represents the weight percentage of a certain component unless otherwise specified.
The short-process high-surface-quality stainless steel rapid slagging method provided by the invention comprises the following process flows of AOD-LTS or LT-continuous casting, wherein in the LTS or LT smelting process, 2-4 kg of rapid slagging agent per ton of steel is added, the alkalinity of furnace slag is adjusted to 1.4-1.6, alloy fine adjustment components are added according to the analysis result of the components of the molten steel, the total amount of the alloy is less than or equal to 500kg, the total stirring flow of gas blown from the bottom of double holes of a steel ladle is 5-7 NL/min per ton of steel, and the stirring time is controlled to be 2-10 min.
Through practice, the rapid slagging agent is adopted to smelt stainless steel, the temperature drop in the smelting process is small, LF furnace treatment is not needed, and stable slag systems are rapidly formed in the stainless steel under short flow and fast pace.
Preferably, the rapid slagging agent comprises the following components in percentage by weight: 22 to 29 percent of CaO and SiO 2 55-60%, mgO 10-20%, si-Ca or Si-Fe alloy powder 1-5%.
Further preferably, the impurities in the rapid slagging agent comprise, by weight: al (Al) 2 O 3 Not more than 5 percent, not more than 1 percent of the total of the iron, manganese and chromium oxides, not more than 0.02 percent of P, not more than 0.02 percent of S and not more than 0.5 percent of water.
The melting point of the rapid slagging agent is 1250-1390 ℃, the melting speed is less than 150s at 1400 ℃, and the melting point is lower than that of other calcium-silicon synthetic slag. In addition, the rapid slagging agent contains MgO with specific content, the fluidity of the slag after slagging is in a reasonable interval, and the slag cannot be too thin or too thick, so that the temperature drop of molten steel and the erosion to refractory materials in the refining process can be effectively reduced.
Wherein, the steel grade smelted by the rapid slagging method is 304 or 316 stainless steel.
Preferably, the AOD steel mixing component w (C) is 1-4%, and the w (Si) is 0.1-3.5%; w (C) is not less than 0.02% after the blowing; the AOD reduction time is 8-10 min, and w (S) is less than or equal to 0.030 percent after reduction.
Preferably, the AOD adjusting period time is 5-10 min, and the components of the molten steel w (S) are controlled to be less than or equal to 0.0050 percent, w (Al) is controlled to be less than or equal to 0.0080 percent and w (Ti) is controlled to be less than or equal to 0.0080 percent according to weight percentage; the temperature before tapping is more than or equal to 1650 ℃.
Preferably, before AOD tapping or LTS entering a station, slagging is carried out until the thickness of the AOD steel is 50-150 mm or the slag amount of 5-20 kg of ton steel is obtained, thereby reducing the adding amount of the synthetic slag.
Further preferably, the temperature of the molten steel before AOD steel tapping or after LTS station entering and slag removing is more than or equal to 1600 ℃.
The preparation method of the rapid slagging agent comprises the following steps:
(1) Mixing, crushing and grinding the slag materials into powder of 50-200 meshes according to the proportion;
(2) Mechanically and uniformly mixing the powder with calcium silicon powder or ferrosilicon powder to obtain a mixture;
(3) Adding a binder, mechanically extruding and forming to prepare particles with the particle size of 5-30 mm, and drying.
In some preferred embodiments, the mix comprises, in weight percent: 30-40% of light-burned dolomite, 0-10% of light-burned magnesium balls, 0-5% of lime, 45-54% of quartz sand and 1-5% of silicon calcium powder and/or silicon iron powder. In further preferred embodiments, the mix comprises, in weight percent: 80-99% of diopside, 0-5% of light-burned magnesium balls, 0-5% of lime, 0-5% of quartz sand and 1-5% of silicon calcium powder and/or silicon iron powder.
Wherein, the light-burned dolomite comprises, by weight, caO more than or equal to 40%, mgO more than or equal to 20%, and Al 2 O 3 Less than or equal to 3 percent, and the total content of the iron, manganese and chromium oxides is less than or equal to 1 percent; the content of MgO in the light-burned magnesium balls is more than 60%; the content of CaO in the lime is more than 85 percent; the quartz sand comprises SiO 2 ≥90％，Al 2 O 3 Less than or equal to 3 percent, and the total content of the iron, manganese and chromium oxides is less than or equal to 1 percent; the diopside comprises 16-26% of CaO and SiO 2 55～70％，MgO 10～18％，Al 2 O 3 Less than or equal to 3 percent, and the total content of the iron, manganese and chromium oxides is less than or equal to 1 percent.
Preferably, the particle size of the calcium silicoferrite powder or the ferrosilicon powder is more than 50 meshes.
The invention grinds the slag materials with specific proportion and then extrudes the slag materials into particles, and the powder inside the slag materials is combined and melted at high temperature to form liquid state and is quickly melted into a slag layer in the smelting process. Because the powder granularity is small, the contact area between the powder is large, a low-melting-point phase formed in the synthetic slag at high temperature is quickly melted, and simultaneously, the ferrosilicon powder or the silico-calcium powder deoxidizes and releases heat to compensate the temperature in the process. Therefore, the rapid slagging agent has the advantage of high slagging speed, and does not need to heat molten steel and stir the molten steel for a long time at a large flow.
The reasons that the invention can realize quick slagging and reduce the temperature drop in the smelting process include: (1) the melting point of the rapid slagging agent is 1250-1390 ℃, the melting speed is less than 150s at 1400 ℃, and the melting point is lower than that of other calcium-silicon synthetic slag; (2) as shown in fig. 1, after the existing slag (such as lime, silica, fluorite and other slag with the granularity of 5-50 mm) is added into the ladle slag layer, the outer surface is in contact reaction with the slag to form a low-melting-point sintering layer and then form a package, but the mass transfer is slow because the inside is still in a solid state; after the rapid slagging agent is added into the slag layer of the steel ladle, the internal powder is combined and melted at high temperature to form liquid and is rapidly melted into the slag layer, as shown in figure 2. Because the powder granularity of the slag charge in the rapid slagging agent is small, the contact area between the powder is large, the low-melting-point phase formed in the synthetic slag is rapidly melted at high temperature, and the ferrosilicon powder or the silico-calcium powder deoxidizes and releases heat to compensate the temperature in the process, the slagging speed is high, the temperature rise of the molten steel and the long-time large-flow stirring are not needed, compared with the direct slag mixing through the slag charges of lime, fluorite, quartz sand and the like, the time for slagging and the whole smelting are shortened, and the temperature drop in the process is reduced; (3) the rapid slagging agent contains a specific amount of MgO, the fluidity of the slag after slagging is in a reasonable interval, and the slag is not too thin or too thick, so that the temperature drop of molten steel and the erosion to refractory materials in the refining process are reduced; (4) in the smelting process, raw slag does not need to be completely removed after AOD steel tapping, the addition amount of synthetic slag is small, and the control of the slag amount of the top slag of the ladle after slag mixing is moderate.
Examples
The invention is further illustrated by the following examples, which are not intended to limit the invention thereto. Experimental procedures without specifying specific conditions in the following examples were carried out according to conventional methods and conditions.
Example 1
Steel grade: 304 stainless steel
The process flow comprises the following steps: 180t AOD-LTS-continuous casting
I, AOD steel mixing components w (C) are 2.2%, w (Si) is 1.3%, and w (C) is 0.028% after blowing;
the reduction time of II AOD is 9min, and w (S) is 0.015 percent after reduction;
III, AOD adjusting period time is 8min, and the components of molten steel to be tapped, namely w (S) =0.0020%, w (Al) =0.0035%, w (Ti) =0.0021% and the temperature before tapping is 1680 ℃;
IV, feeding LTS into a station, slagging off to 150mm, wherein the slag amount is 3.2t, and the temperature of molten steel after slagging off is 1628 ℃;
v, adding 2.5kg of a rapid slagging agent made of diabase ore and the like per ton of steel from a storage bin, adjusting the alkalinity of the slag to 1.6, adding 50kg of electrolytic manganese fine adjustment component, stirring the steel ladle by double-hole bottom blowing gas at a total stirring flow of 6NL/min per ton of steel, and stirring for 8min;
VI, adjusting the bottom blowing flow of the steel ladle to 3NL/min per ton of steel, stirring for 10min, adjusting the flow to 1.0NL/min, stirring for 15min, and taking out of the station for continuous casting.
The melting point of the rapid slagging agent is measured by a laboratory to be 1293 ℃ and the melting speed is measured to be 123s at 1400 ℃. The main components are as follows: caO 25.6%, siO 2 54.3 percent, 15.2 percent of MgO and 4 percent of Si-Fe alloy; the main impurity component is Al according to weight percentage 2 O 3 3%, the total content of Fe, mn and Cr oxides is 0.5%, P is 0.001%, S is 0.003% and water content is 0.1%.
The preparation method of the rapid slagging agent comprises the following steps: i mixing 98% of diopside (CaO 26%, siO) 2 56％，MgO 15.5％，Al 2 O 3 2 percent of iron, manganese and chromium oxide, and 0.5 percent of the total amount of the iron, manganese and chromium oxide) are crushed and ground to prepare powder of 50 to 200 meshes, and then the powder is mechanically and uniformly mixed with 4 percent of silicon iron powder of more than 100 meshes; II, adding a binder, mechanically extruding and forming, preparing into particles of 5-30 mm, and drying.
Example 2
Steel grade: 304 stainless steel
The process flow comprises the following steps: 180t AOD-LTS-continuous casting
I, 3.1 percent of AOD steel mixing components w (C) and 1.9 percent of w (Si); w (C) is 0.031% after blowing;
the reduction time of II AOD is 8min, and w (S) after reduction is 0.013%;
III, adjusting the AOD period for 10min, and controlling the tapping molten steel components w (S) =0.0029%, w (Al) =0.0028%, w (Ti) =0.0025%, and the pre-tapping temperature is 1667 ℃;
IV, introducing LTS into a station, slagging off to 130mm, wherein the slag amount is 2.8t, and the temperature of molten steel after slagging off is 1623 ℃;
v, adding 3kg of a quick slag forming agent made of light-burned dolomite ore, quartz sand and the like per ton of steel from a storage bin, adjusting the alkalinity of slag to 1.52, adding 100kg of low-aluminum ferrosilicon fine-adjustment components, and stirring the steel ladle by double-hole bottom blowing gas at a total stirring flow of 5.5NL/min per ton of steel for 5min;
VI, adjusting the bottom blowing flow of the steel ladle to 4NL/min per ton of steel, and stirring for 10min; then adjusted to 1.5NL/min, stirred for 18min and discharged for continuous casting.
Wherein the melting point of the rapid slagging agent is 1320 ℃, and the melting speed is 147s at 1400 ℃.
The main components are as follows: caO 23.2%, siO 2 56.6 percent of MgO 15.5 percent of calcium silicate powder 2 percent of other impurity components, and the weight percentage of Al 2 O 3 2.1 percent, the total content of iron, manganese and chromium oxides is 0.5 percent, P is 0.01 percent, S is 0.01 percent, and water is 0.03 percent.
The preparation method of the rapid slagging agent comprises the following steps: crushing and grinding 35% of light-burned dolomite, 6% of light-burned magnesium balls, 52% of quartz sand and 5% of lime according to the component proportion to prepare powder of 200 meshes, and mechanically and uniformly mixing the powder with 2% of silicon calcium powder of more than 50 meshes; II, adding a binder, mechanically pressing the mixture into balls, preparing particles of 10-30 mm, and drying.
Example 3
Steel grade: 304 stainless steel
The process flow comprises the following steps: 180t AOD-LTS-continuous casting
I, 3.8 percent of W (C) and 2.2 percent of W (Si) in AOD steel mixing; w (C) is 0.035% after converting;
II, reducing the AOD for 10min, wherein the w (S) is 0.020% after reduction;
III, carrying out AOD (argon oxygen decarburization) adjustment for 10min, and controlling the tapping molten steel components w (S) =0.0035%, w (Al) =0.0029%, w (Ti) =0.0033% and the pre-tapping temperature to be 1686 ℃;
IV, putting LTS into a station, slagging off to 100mm, wherein the slag amount is 2.1t, and the temperature of molten steel after slagging off is 1632 ℃;
v, 2.8kg of rapid slag forming agent made of diopside and the like is added into each ton of steel from a stock bin, the alkalinity of the slag is adjusted to 1.45, 120kg of low-carbon ferrochrome fine adjustment component is added, the total stirring flow of the double-hole bottom blowing gas of the steel ladle is 5NL/min per ton of steel, and the stirring time is 8min;
VI, adjusting the bottom blowing flow of the steel ladle to 5.0NL/min per ton of steel, and stirring for 5min; then, the temperature was adjusted to 2.0NL/min, and the mixture was stirred for 20min and discharged for continuous casting.
Wherein the melting point of the rapid slagging agent is 1350 ℃ and the melting speed is 132s at 1400 ℃.
The main components are as follows: caO 23.2%, siO 2 56.6 percent of MgO 15.5 percent of calcium silicate powder and 1 percent of other impurity components by weight percentage of Al 2 O 3 2.1 percent, 0.5 percent of ferro-manganese-chromium oxide, 0.01 percent of P, 0.01 percent of S and 0.02 percent of water.
The preparation method of the rapid slagging agent comprises the following steps: i mixing 85% of diopside (CaO 18%, siO) 2 65％，MgO 13.5％，Al 2 O 3 3 percent of light-burned magnesium balls, 5 percent of light-burned magnesium balls and 5 percent of lime are crushed and ground according to the component proportion to prepare powder of 200 meshes, and then the powder is mechanically and uniformly mixed with 1 percent of silicon calcium powder of 100 meshes; II, adding a binder, mechanically pressing the mixture into balls, preparing particles of 5-10 mm, and drying.
Comparative example 1
Steel grade: 304 stainless steel
The process flow comprises the following steps: 180t AOD-LTS-LF-continuous casting
AOD is not specially controlled, LTS enters a station and is subjected to slag skimming to 120mm, the temperature of molten steel is 300kg of lime and 200kg of fluorite are added, the flow rate of bottom blowing gas is set to be 2 multiplied by 600NL/min, stirring is carried out for 8min, and then LF power transmission is carried out to increase the temperature.
Comparative example 2
Steel grade: 304 stainless steel
The process flow comprises the following steps: 180t AOD-LTS-LF-continuous casting
And (3) performing no special control on AOD, introducing LTS into a station, slagging off to 120mm, adding quartz sand according to the specific alkalinity requirement, setting the flow of bottom blowing gas to be 2 multiplied by 700NL/min, stirring for 10min, and then transferring to LF (ladle furnace) for power transmission and temperature rise.
Comparative example 3
The process flow comprises the following steps: 180t AOD-LTS-continuous casting
AOD adjusts the alkalinity of the slag to be more than 2.2, LTS enters the station and is skimmed to 120mm, synthetic slag is added, and the components of the synthetic slag are CaO:32 to 36 percent of SiO 2 :48% -54%, mgO: 10-20%, adjusting the alkalinity of the slag to 1.6, setting the flow rate of bottom blowing gas to be 2 multiplied by 700Nl/min, and stirring for 10min.
Summary of test results
By comparing the slagging time (the time when the slag is added to the uniform liquid phase and no agglomeration is observed), the alkalinity after slag adjustment, the temperature drop in the LTS treatment process (after slag skimming and after slag removal), the T.O and S contents in the refined finished steel and the inclusion rate on the surface of the cold plate, the slagging time is reduced, the alkalinity is controlled within the range of 1.4-1.6, the temperature drop in the LTS process is smaller, the oxidation and S increase in the smelting process are reduced, and the inclusion rate on the surface of the cold plate is reduced, which is shown in the following table.
The present invention has been disclosed in the foregoing in terms of preferred embodiments, but it will be understood by those skilled in the art that these embodiments are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. It should be noted that all changes and substitutions that are equivalent to these embodiments are deemed to be within the scope of the claims of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined in the claims.
Claims (10)
1. A short-process high-surface-quality stainless steel smelting rapid slagging method is characterized in that the process flow is AOD-LTS or LT-continuous casting, wherein in the LTS or LT smelting process, 2-4 kg of rapid slagging agent per ton of steel is added, the alkalinity of furnace slag is adjusted to 1.4-1.6, alloy fine adjustment components are added according to the analysis result of the components of the steel liquid, the total amount of the alloy is less than or equal to 500kg, the total stirring flow of gas blown from the bottom of double holes of a steel ladle is 5-7 NL/min per ton of steel, and the stirring time is controlled to be 2-10 min.
2. The method of claim 1, wherein the fast slagging agent comprises, in weight percent: 22 to 29 percent of CaO and SiO 2 55-60%, mgO 10-20%, si-Ca or Si-Fe alloy powder 1-5%.
3. The method of claim 1, wherein the impurities in the fast slagging agent comprise, in weight percent: al (Al) 2 O 3 Less than or equal to 5 percent, less than or equal to 1 percent of the total amount of the iron, manganese and chromium oxides, less than or equal to 0.02 percent of P, less than or equal to 0.02 percent of S and less than or equal to 0.5 percent of water.
4. The method of claim 1, wherein the fast slag former has a melting point of 1250 to 1390 ℃ and a melting rate of less than 150 seconds at 1400 ℃.
5. The method according to claim 1, wherein the fast slag forming agent is prepared by the following method:
(1) Mixing, crushing and grinding the slag materials into powder of 50-200 meshes according to the proportion;
(2) Mechanically mixing the powder with calcium silicate powder or ferrosilicon powder uniformly to obtain a mixture;
(3) Adding a binder, mechanically extruding and forming to prepare particles with the particle size of 5-30 mm, and drying.
6. The method of claim 5, wherein the mix comprises, in weight percent: 30-40% of light-burned dolomite, 0-10% of light-burned magnesium balls, 0-5% of lime, 45-54% of quartz sand and 1-5% of silicon calcium powder and/or silicon iron powder.
7. The method of claim 5, wherein the mix comprises: 80-99% of diopside, 0-5% of light-burned magnesium balls, 0-5% of lime, 0-5% of quartz sand and 1-5% of silicon calcium powder and/or silicon iron powder.
8. The method of claim 1, wherein the AOD steel mixing component w (C) is 1-4 wt%, and w (Si) is 0.1-3.5 wt%; w (C) is not less than 0.02% after the blowing; the AOD reduction time is 8-10 min, and w (S) is less than or equal to 0.030 percent after reduction.
9. The method as claimed in claim 1, wherein the AOD adjusting period is 5-10 min, and the steel tapping molten steel composition w (S) is controlled to be less than or equal to 0.0050%, w (Al) is controlled to be less than or equal to 0.0080%, and w (Ti) is controlled to be less than or equal to 0.0080% by weight.
10. The method of claim 1, wherein slagging-off is carried out before AOD tapping or LTS in-station to a slag amount of 50-150 mm thick or 5-20 kg per ton steel, and the molten steel temperature after slagging-off is more than or equal to 1600 ℃.
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