CN113373278A - RH vacuum furnace slag surface feeding device and furnace slag modification method - Google Patents
RH vacuum furnace slag surface feeding device and furnace slag modification method Download PDFInfo
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- 239000002893 slag Substances 0.000 title claims abstract description 192
- 238000002715 modification method Methods 0.000 title abstract description 3
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 131
- 239000010959 steel Substances 0.000 claims abstract description 131
- 238000000034 method Methods 0.000 claims abstract description 69
- 238000010079 rubber tapping Methods 0.000 claims abstract description 22
- 239000000758 substrate Substances 0.000 claims abstract description 16
- 239000005028 tinplate Substances 0.000 claims abstract description 5
- 239000011575 calcium Substances 0.000 claims description 23
- 238000009749 continuous casting Methods 0.000 claims description 21
- 239000000463 material Substances 0.000 claims description 21
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 18
- 229910052791 calcium Inorganic materials 0.000 claims description 18
- 229910045601 alloy Inorganic materials 0.000 claims description 13
- 239000000956 alloy Substances 0.000 claims description 13
- 229910052782 aluminium Inorganic materials 0.000 claims description 13
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 13
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 238000003756 stirring Methods 0.000 claims description 12
- 238000005275 alloying Methods 0.000 claims description 11
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 11
- 229910052799 carbon Inorganic materials 0.000 claims description 11
- 238000005266 casting Methods 0.000 claims description 11
- 229910052593 corundum Inorganic materials 0.000 claims description 11
- 229910001845 yogo sapphire Inorganic materials 0.000 claims description 11
- 229910052751 metal Inorganic materials 0.000 claims description 10
- 239000002184 metal Substances 0.000 claims description 10
- 229910001634 calcium fluoride Inorganic materials 0.000 claims description 8
- 238000007872 degassing Methods 0.000 claims description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 7
- 230000000903 blocking effect Effects 0.000 claims description 7
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 6
- 239000012535 impurity Substances 0.000 claims description 6
- 230000001681 protective effect Effects 0.000 claims description 6
- 229910052710 silicon Inorganic materials 0.000 claims description 6
- 239000010703 silicon Substances 0.000 claims description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 5
- 239000003795 chemical substances by application Substances 0.000 claims description 5
- 238000005262 decarbonization Methods 0.000 claims description 4
- 239000002923 metal particle Substances 0.000 claims description 4
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 2
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 2
- 239000004571 lime Substances 0.000 claims description 2
- 238000005470 impregnation Methods 0.000 claims 1
- 238000009434 installation Methods 0.000 claims 1
- 230000003749 cleanliness Effects 0.000 abstract description 13
- 239000000203 mixture Substances 0.000 abstract description 11
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- 238000005303 weighing Methods 0.000 abstract description 7
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- 230000007547 defect Effects 0.000 abstract description 2
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- 239000003607 modifier Substances 0.000 abstract 1
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- 239000007789 gas Substances 0.000 description 20
- 238000003723 Smelting Methods 0.000 description 10
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- 238000009847 ladle furnace Methods 0.000 description 5
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- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
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- 238000003860 storage Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 3
- 238000007670 refining Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
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- 229910052757 nitrogen Inorganic materials 0.000 description 2
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- 229910052722 tritium Inorganic materials 0.000 description 2
- 229910000976 Electrical steel Inorganic materials 0.000 description 1
- 229910000655 Killed steel Inorganic materials 0.000 description 1
- -1 automobile plates Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
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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
-
- 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
- C21C7/06—Deoxidising, e.g. killing
-
- 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
- C21C7/10—Handling in a vacuum
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Analytical Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
本申请公开了一种RH真空炉渣面加料装置及炉渣改质方法，属于炼钢技术领域。RH真空炉渣面加料装置包括高位料仓、称料仓、可伸缩转动的加料导管。通过在RH真空炉处理工位安装加料装置，实现在RH真空炉处理阶段，随时向渣面加入脱氧剂、合成渣等调整钢包渣成分。克服了传统RH真空炉处理过程无法直接调整炉渣成分的操作缺陷，尤其对于转炉沸腾出钢，直接运至RH深脱碳处理的钢种，如汽车板、马口铁、SPHD等，可在RH脱碳处理后，由该真空加料装置向钢包渣面加入脱氧剂或改质剂，并结合RH处理工艺的改进，将炉渣氧化性降低，提高钢水洁净度和浇注性能。该技术对于改善RH单联工艺冷轧基板钢种洁净度及浇注性能具有重要意义。
The application discloses a RH vacuum slag surface feeding device and a slag modification method, which belong to the technical field of steelmaking. The RH vacuum slag surface feeding device includes a high-level silo, a weighing silo, and a retractable and rotating feeding conduit. By installing a feeding device at the processing station of the RH vacuum furnace, it is possible to add deoxidizers, synthetic slag, etc. to the slag surface at any time to adjust the composition of the ladle slag during the processing stage of the RH vacuum furnace. It overcomes the operational defect that the traditional RH vacuum furnace treatment process cannot directly adjust the slag composition, especially for the boiling tapping of the converter, which is directly transported to the steel grades for deep decarburization treatment at RH, such as automobile sheets, tinplate, SPHD, etc., which can be decarburized at RH. After treatment, deoxidizer or modifier is added to the ladle slag surface by the vacuum feeding device, and combined with the improvement of RH treatment process, the oxidizing property of the slag is reduced, and the cleanliness and pouring performance of molten steel are improved. This technology is of great significance for improving the cleanliness and pouring performance of cold-rolled substrate steel grades in the RH single-pass process.
Description
Technical Field
The invention belongs to the technical field of steel making, and particularly relates to an RH vacuum furnace slag surface feeding device and a furnace slag modifying method.
Background
The cold-rolled substrate is a product obtained by rolling a hot-rolled coil at a temperature lower than the recrystallization temperature, and is widely used in automobile manufacturing, electric products, and the like. The steel grade is low-carbon low-silicon aluminum killed steel, low-phosphorus low-sulfur low-gas content and very low-gas content are required, and the requirement on comprehensive cleanliness is also very high, so that the requirement on the smelting process of the steel grade is strict.
At present, the smelting process route for producing low-carbon cold-rolled substrate steel by domestic and foreign steel manufacturers mainly comprises the following steps: 1) BOF-RH-CC; 2) BOF-CAS (ANS) -CC; 3) BOF-LF (calcium treated) -CC (CSP, FTSC); 4) a few domestic iron and steel enterprises adopt a BOF-RH-LF (calcium treatment) -CC process. For cold rolled products with ultra-low carbon, high cleanliness and extremely low gas content requirements, IF steel and the like mainly adopt the smelting process route (1), steel is tapped in a converter in a boiling way, the steel is transported to RH deep decarburization treatment, then alloying, degassing, impurity removal and the like are carried out, and then the steel is transported to continuous casting and pouring. The process has short flow and low production cost, but because the steel is tapped by boiling the converter, the oxidability of the molten steel and the slag is very strong, the oxygen in the molten steel can be removed during RH alloying, but the oxidability of the slag is very high, the T.Fe content is 10-20 percent, so that the RH breaking can not be carried out with calcium treatment,the slag continuously oxidizes the molten steel during continuous casting to produce a large amount of Al2O3The problem of nozzle clogging is very serious, the submerged nozzle needs to be replaced when 2-4 furnaces are poured, the total continuous pouring furnace number is more than 6-10 furnaces per tundish, and the production efficiency is relatively low. The smelting process routes of (2) and (3) are that alloy is added for deoxidation alloying when the converter taps, slag is added for slagging, then the mixture is conveyed to CAS (ANS), LF (ladle furnace) is used for refining and adjusting components and temperature, soft stirring and calcium treatment are carried out, and finally the mixture is conveyed to continuous casting and pouring. The process route can carry out calcium treatment, so that the pouring performance of the molten steel is obviously improved. However, the process method can only be applied to steel grades with relatively high C content (more than or equal to 0.03 percent of C), because deep decarburization can not be carried out without a vacuum furnace, meanwhile, the C content of general molten steel subjected to LF refining treatment can be increased to a certain extent, meanwhile, the gas content of N, H, T.O and the like can also be obviously increased, and the process method can not be applied to cold-rolled substrate steel grades with ultra-low carbon, high gas content and high cleanliness. In the smelting process (4), recarburization in the LF refining process is considered firstly, effective decarburization can be realized by RH treatment, and Al is removed simultaneously2O3Carrying out inclusion; secondly to prevent Al2O3The inclusion blocks the nozzle and affects the castability of molten steel, and the calcium line is fed after LF treatment is finished to modify the inclusion. The production requirements of most cold-rolled substrate steel grades can be met, the single process route is long, the production cost is very high, and meanwhile, the production requirements of high-end cold-rolled products such as high-end silicon steel, automobile plates and the like with the C content of less than 50ppm, the N content of less than 20ppm, the H content of less than 2ppm and the like cannot be met.
The problem of the nodulation of the pouring nozzle of the cold-rolled substrate steel is a key factor influencing the improvement of the yield and the quality of the series of products. Therefore, in order to solve the problems existing in the production process of the steel grade, many researchers adopt some improved methods, such as adding alloy and deoxidizer to the converter tapping to reduce the oxidability of the slag, and then carrying out RH treatment, but because RH needs to be decarbonized by oxygen in molten steel, the oxidability of the slag is kept higher, generally between 8 and 15 percent, and the problem of nozzle nodulation in the subsequent continuous casting process is reduced, but cannot be solved. On the basis, the modification of the furnace slag in the RH treatment process is added, a slag surface deoxidizer is added from a vacuum inner bin, and because the RH vacuum furnace treatment process does not have ladle bottom blowing, most deoxidizers added in a vacuum chamber are dissolved in molten steel after passing through the molten steel, and the deoxidizing capacity of the furnace slag is greatly weakened after floating to the slag surface. Generally, no stock bin is arranged on an RH station, a deoxidizer is directly added to the slag surface, so that the deoxidizer is added to the slag surface after RH is broken, in order to ensure that the deoxidizer is uniformly mixed with the slag, ladle bottom blowing is required to be opened (the ladle bottom blowing is not opened in the RH treatment process), the cleanliness of molten steel is deteriorated after the bottom blowing stirring, the gas content of the molten steel is increased, and if the bottom blowing is not opened, the deoxidizer is added to the slag surface, cannot fully react with the slag, and the oxidizability of the slag is reduced.
Disclosure of Invention
The invention aims to provide an RH vacuum furnace slag surface charging device and a furnace slag modifying method, which aim to overcome the defects in the prior art.
In order to achieve the purpose, the invention provides an RH vacuum furnace slag surface feeding device which comprises independent feeding devices arranged on two sides above a ladle treatment position of an RH vacuum furnace, wherein each independent feeding device comprises a high-level material bin, a material weighing bin and a telescopic rotary feeding conduit, the high-level material bin, the material weighing bin and a feeding guide pipe are respectively connected through a vibration blanking conduit, the high-level material bin and the material weighing bin are respectively provided with an electric control switch to open a feeding valve, materials are fed into a slag surface of the ladle through the feeding conduit, and the feeding conduit freely moves and feeds materials in a slag surface area and an opposite area. And a discharge port at the bottom of the feeding conduit is positioned in a triangular area formed by the RH double-soaking pipe and the steel ladle wall and a symmetrical triangular area.
The invention also provides a method for modifying the slag of the RH vacuum furnace, which comprises the step of adopting the charging device, and the method for modifying the slag comprises the following steps: the converter blocks slag and taps, lime and synthetic slag are added into a ladle for slag regulation after tapping, then molten steel is transported to RH for treatment, a RH station is decarburized, various alloys are added into a vacuum alloy bin for deoxidation alloying after decarburizing, meanwhile, a slag surface deoxidizer is added to the slag surface of the ladle by an RH material distribution device, the height of the ladle is reduced by 10-30cm when the slag surface deoxidizer is added, then the steel ladle is lifted to the original position again, the steel ladle is lifted and lowered repeatedly for a plurality of times until the addition of the slag surface deoxidizer is finished, the flow rate of the lifting gas is reduced to 120 plus 150NL/min when the slag surface deoxidizer is added, the E5 vacuum pump is closed, after the alloying is finished and the addition of the slag surface deoxidizer is finished, the flow rate of the lifting gas is restored to 180-220NL/min, the vacuum pump E5 is started, the molten steel is continuously degassed circularly for more than 8min, and then the steel is tapped by breaking the hole, directly hoisted to continuous casting pouring or is transferred to the continuous casting pouring after calcium treatment and soft stirring.
Preferably, in the tapping process, a slag blocking cone or a sliding plate is adopted for slag blocking, the slag amount is controlled to be less than or equal to 2kg/t molten steel, and the synthetic slag comprises the following components in percentage by mass: 40-50% of Al2O3：15-25％、CaF2: 3-8% of metal aluminum powder: 15-25%, MgO less than or equal to 8%, and other inevitable impurities.
Preferably, the distance between the bottom of the feeding conduit and the slag surface of the steel ladle is kept between 0.2 and 0.6m when the slag surface deoxidant is added, a discharge port at the bottom of the feeding conduit is positioned in a slag surface triangular area and a symmetrical triangular area which are formed by the RH double-immersion pipe and the steel ladle wall, the speed of the slag surface deoxidant is controlled between 50 and 100kg/min, and the lifting speed of the steel ladle is controlled between 0.5 and 1.0 m/min.
Preferably, the slag surface deoxidizer can be a deoxidizer synthesized by metal aluminum, metal silicon or deoxidized metal and slag charge, and the synthesized slag surface deoxidizer comprises the following components in percentage by mass: 30-40% of Al2O3：10-20％、CaF2Less than or equal to 5 percent, less than or equal to 8 percent of MgO, metal particles of calcium, aluminum, silicon and the like: 30-45% and other inevitable impurities.
Preferably, ultra-low carbon cold-rolled substrate steel grades such as IF steel, DC04, DC05 and the like are produced, RH treatment net circulation is finished, the ultra-low carbon cold-rolled substrate steel grades are directly conveyed to continuous casting for protective casting, IF RH treatment base plate steel grades such as tinplate and the like are treated by RH, pure calcium wires are fed after the RH treatment net circulation treatment is finished, the content of Ca in molten steel is controlled to be 15-25ppm, then soft stirring is carried out for more than 10min, and the ultra-low carbon cold-rolled substrate steel grades are conveyed to continuous casting protective casting.
Preferably, the T.Fe in the ladle slag obtained by the method during RH breaking tapping is less than 3%, and the number of continuous casting furnaces is more than or equal to 14.
The principle of the smelting process of the invention is as follows:
the main alloy elements of the low-carbon cold-rolled substrate steel are Al and Mn, and part of the steel contains a small amount of other micro-elementsThe content of alloy elements, Si, is generally required to be below 0.03%, Al is the main deoxidizing element of the steel, therefore, the inclusions in the molten steel mainly comprise Al2O3Mainly comprises the following steps. In addition to high cleanliness requirements, high requirements are also placed on the gas content of N, H, T.O and the like in medium-high-end cold-rolled base plate steel types such as automobile plates, tinplate, galvanized plates and the like, so a BOF-RH-CC process is generally adopted, in order to reduce molten steel suction in the converter tapping process, the converter tapping basically adopts a process operation mode of boiling tapping or semi-boiling tapping, meanwhile, oxygen is remained and transported to RH for decarburization treatment, so that the molten steel and slag oxidability are integrally high, after RH decarburization is finished, aluminum is added for deoxidation, the aluminum in the molten steel can be deoxidized to a lower level, but the slag oxidability is difficult to be reduced to a lower level at an RH station. Therefore, the RH tapping can not be carried out with calcium treatment, and simultaneously, the continuous oxidation of the slag during the continuous casting process pollutes the molten steel, so that the pouring performance of the molten steel is very poor.
In the process of producing the cold-rolled base plate by the traditional process, in order to reduce the problems, a certain slag surface deoxidizer is added into the steel of the cold-rolled base plate with higher carbon content discharged from a converter to reduce the oxidability of slag, but generally the T.Fe is still more than 8 percent, and the cleanliness and the pouring performance of molten steel are not obviously and substantially improved. Some steel enterprises also try to add slag deoxidizers at the RH station, add the deoxidizers from the vacuum tank or manually add the deoxidizers to the slag surface, because the RH vacuum furnace has no bottom blowing, and all slag is squeezed by the RH dip pipes into a triangular area formed by the two dip pipes and the surrounding wall, the slag flowability is very poor, the deoxidizers are mainly burnt on the surface of the slag after the slag surface deoxidizers are added, and no obvious reducing effect is generated on the oxidizability of the slag. If slag surface deoxidizing agent is added after RH is broken, and the ladle is started to blow and stir, the oxidizability of the slag can be reduced, but air suction is increased when molten steel overturns, meanwhile, a large amount of Al in the molten steel participates in the deoxidation reaction of the slag, the cleanliness of the molten steel is seriously deteriorated, and the process effect is very poor.
In order to solve the problems, the invention designs a simple RH vacuum furnace ladle slag surface deoxidizing agent adding device, when molten steel is deoxidized and alloyed by adding alloy, an automatic telescopic rotating conduit is adopted, and slag surface deoxidizing agents are uniformly added into a triangular area formed by two RH dip pipes and a ladle wall. At this time, the decarburization of the molten steel is completed, and the slag is upgraded without lowering the oxygen content in the molten steel, that is, without affecting the decarburization effect. In order to solve the problems that a slag surface deoxidizer and slag react fully and does not pollute molten steel, in the process of adding the slag surface deoxidizer, a steel ladle is repeatedly and automatically lifted in a certain height range, meanwhile, the pressure of molten steel is reduced, a primary vacuum pump is closed to increase the pressure of a vacuum chamber, so that the circulating flow of the molten steel is reduced, the molten steel in the vacuum chamber is reduced, the liquid level of the molten steel in the steel ladle is increased, the slag and the slag surface deoxidizer are covered and stirred by upper molten steel in the process of lifting the steel ladle, the high-temperature molten steel and the upper and lower strong disturbance are realized, the slag surface deoxidizer and the original oxidizability steel ladle slag are fully melted and reacted, the oxidizability of the slag is greatly reduced, and the T.Fe in the slag can be controlled below 3 percent to reach the level of white slag. Meanwhile, because the steel ladle is not broken empty and the bottom blowing of the steel ladle is not started, the steel ladle drives the molten steel to move up and down in a short distance range, the aluminum content and the cleanliness of the whole molten steel cannot be influenced, simultaneously, after the slag is modified, the gas flow is increased again, the closed class-1 vacuum pump is started, the circulating flow of the molten steel is recovered, the degassing can be continued through the circulating treatment under high vacuum, and simultaneously, impurities generated in the slag modification process are fully floated and removed, so that the cleanliness of the molten steel is ensured. After the oxidizability of the slag is greatly reduced, whether calcium treatment is continued after RH tapping can be selected according to the steel grade requirement, IF the IF steel needs to strictly control the content of dissolved Ca, RH is directly conveyed to continuous casting and pouring after being broken; the tinplate, the galvanized plate and the like can be subjected to calcium treatment and then conveyed to continuous casting, so that the casting performance is further improved.
Compared with the prior art, the invention has the beneficial effects that:
(1) the simple and convenient RH station slag surface automatic slag material adding device is designed, the RH station slag surface is rapidly added, the operation of adding slag materials or manually adding slag materials into molten steel from a vacuum storage bin is cancelled, the molten steel is polluted by directly adding slag materials into the vacuum storage bin, and the labor intensity of manually adding slag surfaces is high;
(2) the high-efficiency modification of the slag in the RH treatment process of the cold-rolled substrate steel grade is realized, the gas content of the molten steel is not increased, and the cleanliness of the molten steel is ensured;
(3) the oxidizability of slag of the RH single-linkage process cold-rolled substrate steel is greatly reduced, the pouring performance of molten steel is obviously improved, the number of continuous casting furnaces is increased, the production efficiency is improved, the production cost is reduced, and the refractory consumption is reduced, so that the method is an economic, efficient and environment-friendly process method.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic view of an RH vacuum slag surface charging device in the present application;
FIG. 2 is a schematic view of an RH vacuum furnace;
fig. 3 is a schematic top view of the vacuum charging device charging the ladle slag surface.
Wherein: 1-high level stock bin; 2-weighing a stock bin; 3-a feed conduit; 4-RH double-soaking tube; 5-ladle slag surface; 6-ladle wall; 7-molten steel; 8-slag surface triangle area; 9-vibrating blanking conduit.
Detailed Description
The technical solutions in the embodiments of the present invention will be described in detail below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
As shown in fig. 1 to 3, an RH vacuum slag surface charging device in which independent charging devices are installed at both sides above a ladle treatment position of an RH vacuum furnace, the charging device includes: high-order feed bin 1, title feed bin 2, scalable rotation feeding pipe 3, high-order feed bin 1 with title feed bin 2, title feed bin 2 and feeding pipe 3 are connected by vibration unloading pipe 9 respectively, and high-order feed bin 1, title feed bin 2 all adopt electric control switch to open the charging valve, add the ladle slag face with the material through feeding pipe 3, and feeding pipe 3 is reinforced in slag face trigone 8 and the regional free removal in opposite face. And a discharge hole at the bottom of the charging conduit 3 is positioned in a slag surface triangular area 8 and a symmetrical triangular area thereof, which are formed by the RH double immersion pipe 4 and the ladle wall 6 in a surrounding way.
The invention also provides a method for modifying the slag of the RH vacuum furnace, which is further explained by combining with specific embodiments.
Example 1:
and smelting by adopting a 180t converter, wherein the smelting steel is IF steel.
(1) During the tapping process of the converter, a slag blocking cone is adopted for slag blocking, synthetic slag is added, and the slag discharging amount and the synthetic slag components are shown in table 1.
TABLE 1 converter tapping slag amount and synthetic slag composition
| Furnace number | Amount of slag in kg/t | CaO，％ | Al2O3，％ | CaF2，％ | Metal aluminium powder | MgO，％ |
| (a) | 1.0 | 50 | 25 | 3 | 15 | 2 |
| (b) | 1.5 | 45 | 20 | 5 | 20 | 4 |
| (c) | 2.0 | 40 | 15 | 8 | 25 | 6 |
(2) And after tapping of the converter is finished, the molten steel is conveyed to an RH station for decarburization treatment. After the decarbonization is finished, various alloys are added from the vacuum alloy bin for deoxidation alloying.
(3) In the RH deoxidation alloying process, a slag surface deoxidizer is added into a triangular area 8 formed by enclosing the RH double-dipping pipe 4 and a steel ladle wall 6 and a symmetrical triangular area thereof through the high-level stock bin 1, the material weighing bin 2 and the feeding conduit 3, and the height of the steel ladle is repeatedly adjusted, wherein the distance from the bottom of the feeding conduit 3 to the slag surface of the steel ladle is kept between 0.2 and 0.6m until the addition of the slag surface deoxidizer is finished.
(4) When the RH feeding device adds the slag surface deoxidant, the E5 vacuum pump is closed, and the RH vacuum groove lifting gas flow, the slag surface deoxidant adding speed and the ladle lifting speed are shown in the table 2. The composition of the deoxidizer on the slag surface is shown in Table 3.
TABLE 2 RH parameters at the time of addition of slag surface deoxidant
| Furnace number | RH vacuum tank lift gas flow NL/min | Speed of adding deoxidant in kg/min | Lifting speed of ladle, m/min |
| (a) | 120 | 50 | 1.00 |
| (b) | 135 | 75 | 0.85 |
| (c) | 150 | 100 | 0.50 |
TABLE 3 slag surface deoxidizer composition
| Furnace number | CaO，％ | Al2O3，％ | CaF2，％ | MgO，％ | Metal particles,% of |
| (a) | 30 | 20 | 1 | 2 | Silicon, 45 |
| (b) | 35 | 15 | 3 | 4 | Aluminum, 40 |
| (c) | 40 | 10 | 5 | 6 | Calcium, 30 |
(5) After the RH slag surface deoxidizer is added, the E5 vacuum pump is started, and the RH vacuum groove promotes the gas flow and the molten steel circulation degassing time as shown in Table 4.
TABLE 4 RH parameters at the end of addition of deoxidizer on slag surface
| Furnace number | RH vacuum tank lift gas flow NL/min | Cyclic degassing time of molten steel min |
| (a) | 180 | 15 |
| (b) | 200 | 12 |
| (c) | 220 | 9 |
(6) And when the RH hollow tapping is carried out, the ladle slag is sampled for component analysis, and T.Fe in the slag is shown in the table 5. And (4) hoisting and conveying the molten steel to continuous casting for protective casting, wherein the liquid level of the crystallizer is stable in the casting process, and the total casting is carried out for 15 times.
TABLE 5 T.Fe content in ladle slag
| Furnace number | T.Fe，％ |
| (a) | 3.0 |
| (b) | 1.5 |
| (c) | 0.5 |
Example 2:
and smelting by adopting a 180t converter, wherein the smelting steel is ST5 steel.
(1) During the tapping process of the converter, the sliding plate is used for blocking slag, and synthetic slag is added, and the slag discharging amount and the synthetic slag components are shown in table 6.
TABLE 6 converter tapping slag amount and synthetic slag composition
| Furnace number | Amount of slag in kg/t | CaO，％ | Al2O3，％ | CaF2，％ | Metal aluminium powder | MgO，％ |
| (a) | 1.0 | 50 | 25 | 3 | 15 | 2 |
| (b) | 1.5 | 45 | 20 | 5 | 20 | 4 |
| (c) | 2.0 | 40 | 15 | 8 | 25 | 6 |
(2) And after tapping of the converter is finished, the molten steel is conveyed to an RH station for decarburization treatment. After the decarbonization is finished, various alloys are added from the vacuum alloy bin for deoxidation alloying.
(3) In the RH deoxidation alloying process, a slag surface deoxidizer is added into a triangular area 8 formed by enclosing the RH double-dipping pipe 4 and a steel ladle wall 6 and a symmetrical triangular area thereof through the high-level stock bin 1, the material weighing bin 2 and the feeding conduit 3, and the height of the steel ladle is repeatedly adjusted, wherein the distance from the bottom of the feeding conduit 3 to the slag surface of the steel ladle is kept between 0.2 and 0.6m until the addition of the slag surface deoxidizer is finished.
(4) When the RH feeding device adds the slag surface deoxidant, the E5 vacuum pump is closed, and the RH vacuum groove lifting gas flow, the slag surface deoxidant adding speed and the ladle lifting speed are shown in the table 7. The composition of the deoxidizer on the slag surface is shown in Table 8.
TABLE 7 RH parameters at the time of addition of slag surface deoxidant
| Furnace number | RH vacuum tank lift gas flow NL/min | Speed of adding deoxidant in kg/min | Lifting speed of ladle, m/min |
| (a) | 120 | 100 | 0.75 |
| (b) | 135 | 80 | 1.00 |
| (c) | 150 | 55 | 0.55 |
TABLE 8 slag surface deoxidizer composition
| Furnace number | CaO，％ | Al2O3，％ | CaF2，％ | MgO，％ | Metal particles,% of |
| (a) | 30 | 20 | 1 | 2 | Silicon, 45 |
| (b) | 35 | 15 | 3 | 4 | Aluminum, 40 |
| (c) | 40 | 10 | 5 | 6 | Calcium, 30 |
(5) After the RH slag surface deoxidizer is added, the E5 vacuum pump is started, and the RH vacuum tank promotes the gas flow and the molten steel cycle degassing time are shown in Table 9.
TABLE 9 RH parameter condition after the addition of slag surface deoxidizer
| Furnace number | RH vacuum tank lift gas flow NL/min | Cyclic degassing time of molten steel min |
| (a) | 180 | 12 |
| (b) | 200 | 15 |
| (c) | 220 | 10 |
(6) After the RH hollow tapping, the molten steel is subjected to calcium treatment and soft stirring. The Ca content of the molten steel and the soft stirring time are shown in Table 10.
TABLE 10 Ca content of molten steel and Soft stirring time
| Furnace number | Ca content in ppm of molten steel | Time of soft stirring, min |
| (a) | 15 | 15 |
| (b) | 20 | 13 |
| (c) | 25 | 11 |
(7) After the RH soft stirring was completed, the ladle slag was sampled for composition analysis, and t.fe in the slag was as shown in table 11. And hoisting and conveying the molten steel to continuous casting for protective casting, wherein the liquid level of the crystallizer is stable in the casting process, and the casting is carried out for 16 times.
TABLE 11 T.Fe content in ladle slag
| Furnace number | T.Fe，％ |
| (a) | 2.5 |
| (b) | 1.3 |
| (c) | 0.6 |
In summary, compared with the prior art, the invention has the following beneficial effects: (1) the simple and convenient RH station slag surface automatic slag material adding device is designed, the RH station slag surface is rapidly added, the operation of adding slag materials or manually adding slag materials into molten steel from a vacuum storage bin is cancelled, the molten steel is polluted by directly adding slag materials into the vacuum storage bin, and the labor intensity of manually adding slag surfaces is high; (2) the high-efficiency modification of the slag in the RH treatment process of the cold-rolled substrate steel grade is realized, the gas content of the molten steel is not increased, and the cleanliness of the molten steel is ensured; (3) the oxidizability of slag of the RH single-linkage process cold-rolled substrate steel is greatly reduced, the pouring performance of molten steel is obviously improved, the number of continuous casting furnaces is increased, the production efficiency is improved, the production cost is reduced, and the refractory consumption is reduced, so that the method is an economic, efficient and environment-friendly process method.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The foregoing is merely a detailed description of the present application, and it should be noted that modifications and embellishments could be made by those skilled in the art without departing from the principle of the present application, and these should also be considered as the protection scope of the present application.
Claims (8)
1. The utility model provides a RH vacuum furnace slag surface feeding device which characterized in that: installing independent feeding devices on two sides above a ladle treatment position of the RH vacuum furnace, wherein the feeding devices comprise: high-order feed bin (1), title feed bin (2), scalable pivoted reinforced pipe (3), high-order feed bin (1) and title feed bin (2), title feed bin (2) are connected by vibration unloading pipe (9) respectively with reinforced pipe (3), high-order feed bin (1), title feed bin (2) all adopt electric control switch to open reinforced valve, add ladle slag face through reinforced pipe (3) with the material, reinforced pipe (3) are reinforced in slag face trigone (8) and the regional free removal in opposite.
2. The RH vacuum slag surface charging device according to claim 1, wherein: and a discharge hole at the bottom of the charging conduit (3) is positioned in a slag surface triangular area (8) and a symmetrical triangular area which are formed by enclosing the RH double-impregnation pipe (4) and the ladle wall (6).
3. A method for modifying RH vacuum furnace slag is characterized in that: the charging installation according to claim 1, the slag upgrading process comprising: the converter blocks slag and taps, add lime, synthetic slag and regulate slag in the ladle after tapping, then transport the molten steel to RH and process, the RH station carries on the decarbonization process, decarbonization finish add various alloys to carry on the deoxidation alloying by the alloy storehouse of vacuum, meanwhile, add the slag surface deoxidizer to the slag surface of ladle by RH distributing device, while adding the slag surface deoxidizer, reduce the height of ladle by 10-30cm, then rise to the home position again, the ladle is hoisted and lowered and moved repeatedly several times, until the slag surface deoxidizer is added completely; when the slag surface deoxidizing agent is added, the flow rate of the lifting gas is reduced to 150NL/min, an E5 vacuum pump is closed, after alloying and slag surface deoxidizing agent addition are finished, the flow rate of the lifting gas is restored to 220NL/min, an E5 vacuum pump is started, molten steel continues to be subjected to circular degassing, degassing time is more than 8min, then steel is obtained after breaking the air, and the steel is directly lifted to continuous casting pouring or is transferred to pouring continuous casting after calcium treatment and soft stirring.
4. The method for upgrading RH vacuum furnace slag according to claim 3, wherein: in the tapping process, a slag blocking cone or a sliding plate is adopted for blocking slag, the slag amount is controlled to be less than or equal to 2kg/t molten steel, and the synthetic slag comprises the following components in percentage by mass: 40-50% of Al2O3：15-25％、CaF2: 3-8% of metal aluminum powder: 15-25%, MgO less than or equal to 8%, and other inevitable impurities.
5. The method for upgrading RH vacuum furnace slag according to claim 3, wherein: when the slag surface deoxidant is added, the distance between the bottom of the feeding conduit (3) and the slag surface of the steel ladle is kept between 0.2 and 0.6m, a discharge port at the bottom of the feeding conduit (3) is positioned in a slag surface triangular area (8) and a triangular area symmetrical to the slag surface triangular area, the speed of the slag surface deoxidant is controlled between 50 and 100kg/min, and the lifting speed of the steel ladle is controlled between 0.5 and 1.0 m/min.
6. The method for upgrading RH vacuum furnace slag according to claim 3, wherein: the slag surface deoxidizer can be synthesized by metal aluminum, metal silicon or deoxidized metal and slag, and the synthesized slag surface deoxidizer comprises the following components in percentage by mass: 30-40% of Al2O3：10-20％、CaF2Less than or equal to 5 percent, less than or equal to 8 percent of MgO, metal particles of calcium, aluminum, silicon and the like: 30-45% and other inevitable impurities.
7. The method for upgrading RH vacuum furnace slag according to claim 3, wherein: producing ultra-low carbon cold-rolled substrate steel grades such as IF steel, DC04, DC05 and the like, directly conveying to continuous casting for protective casting after RH treatment net circulation is finished, IF RH treatment is carried out on cold-rolled substrate steel grades such as tinplate and the like, finishing the net circulation treatment, feeding pure calcium wires, controlling the Ca content of molten steel to be 15-25ppm, then carrying out soft stirring for more than 10min, and conveying to continuous casting protective casting.
8. The method for upgrading RH vacuum furnace slag according to claim 3, wherein: the T.Fe in the ladle slag obtained by the production method during RH breaking tapping is less than 3 percent, and the number of continuous casting furnaces is more than or equal to 14.
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