A nanocrystalline master alloy melting and casting system and a melting and casting method

Abstract

The present invention relates to the field of metallurgical technology, and discloses a nanocrystalline master alloy melting and casting system and a melting and casting method. The system includes: a melting furnace, a steel pouring channel, and an ingot mold device; the melting furnace is used for melting molten steel, the steel pouring channel is used for pouring the molten steel melted by the melting furnace into the ingot mold device, and the ingot mold device includes an ingot mold body, and the ingot mold body is used for accommodating the molten steel poured by the steel pouring channel; the steel pouring channel includes a refractory material filling layer and a glass lining; the ingot mold device further includes a liquid cooling plate; after each pouring is completed, only the glass lining needs to be cleaned in the pouring channel, and a small amount of plastic material is used to fix the new glass lining, and then steel can be poured again, which greatly reduces the wear of the pouring channel body and improves the service life of the pouring channel; since the coolant circulates inside the liquid cooling plate, the cooling rate of the nanocrystalline master alloy is increased, the service life of the ingot mold body is guaranteed, and at the same time, the preparation efficiency and the product quality are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgy, and particularly to a nanocrystalline master alloy melting and casting system and a melting and casting method. Background Art

[0002] For the preparation of conventional nanocrystalline master alloys, molten steel is usually generated by a melting furnace, and then the molten steel is poured into a mold through a casting channel. After the master alloy is formed, it is taken out.

[0003] However, during the cooling process of the molten steel, a large amount of heat released by the metal during cooling and solidification is absorbed by the ingot mold body, and after absorption, it is conducted to the air through thermal radiation. The heat exchange speed is slow, and the parts of the mold in contact with the molten steel are prone to adhesion, scratching, chipping and other phenomena, which reduces the production efficiency, affects the service life of the mold, and increases the cost; in addition, the quality of the master alloy product is also reduced.

[0004] Therefore, how to improve the efficiency of nanocrystalline master alloy melting and casting, improve the product quality, and reduce the production cost has become an urgent technical problem in this field.

[0005] In addition, high-end nanocrystalline ribbons are developing towards ultra-wide and ultra-thin directions, requiring the molten steel to have higher fluidity and cleanliness. The nanocrystalline alloy melt has a very high viscosity because it contains a large amount of Nb element, so its fluidity is very poor. The fluidity of the melt can be improved by significantly increasing the temperature of the molten steel or adding metalloid elements such as Si, B, and P. Moreover, for the preparation of nanocrystalline ultra-thin ribbons below 18um, an ultra-narrow nozzle with a slit width below 0.2mm must be used. Once the inclusions in the molten steel accumulate and form nodules at the nozzle, it will change the molten steel flow field at the nozzle, causing defects such as scratches on the ribbon surface, and even causing the package to move and terminate the ribbon production. This puts higher requirements on the purity of the molten steel. And raw materials such as ferrophosphorus and ferrophosphorus contain a large amount of Al impurities, which directly affect the cleanliness of the molten steel. Therefore, reducing the content of Al impurities in the molten steel is a problem that must be solved in the production of wide-width ultra-thin ribbons and is one of the problems that must be solved to improve the quality of the master alloy. Summary of the Invention

[0006] The purpose of the present invention is to provide a nanocrystalline master alloy melting and casting system and a melting and casting method, and the nanocrystalline master alloy melting and casting system can improve the efficiency of nanocrystalline master alloy melting and casting, improve the product quality, and reduce the production cost.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] A nanocrystalline master alloy casting system, comprising: a melting furnace, a steel pouring channel, and an ingot mold device; the melting furnace is used for melting molten steel, the steel pouring channel is used for pouring the molten steel prepared by the melting furnace into the ingot mold device, and the ingot mold device includes an ingot mold body, and the ingot mold body is used for accommodating the molten steel poured by the steel pouring channel so that the molten steel cools in the ingot mold body; the steel pouring channel sequentially includes a housing, a refractory material filling layer, and a glass inner lining from outside to inside; the inner cavity of the glass inner lining constitutes the pouring channel body, and the pouring channel body is used for flowing molten steel; the ingot mold device further includes a liquid cooling plate, and the liquid cooling plate is installed at the bottom of the ingot mold body, and a coolant flows inside the liquid cooling plate.

[0009] In this nanocrystalline master alloy casting system, when the molten steel is poured from the melting furnace to the ingot mold body through the steel pouring channel, since there is a glass inner lining in the inner cavity of the refractory material filling layer, the surface of the glass material is relatively smooth and non-wetting with the molten steel, which can improve the flow rate of the molten steel, and the glass has good thermal stability and low thermal conductivity at high temperatures, which can reduce oxidation and temperature drop, and is not easy to react with the molten steel to contaminate the molten steel; after the pouring is completed, the glass material will undergo a crystal form transformation when cooled to form cracks, which is easy to clean the surface of the pouring channel body. The glass residues and residual steel after cleaning can be remelted in the furnace, and the glass can form a protective slag after melting, and the steel yield is high. After each pouring is completed, only the glass inner lining needs to be cleaned, and a small amount of plastic material is used to fix the new glass inner lining to pour steel again, which greatly reduces the wear of the pouring channel body and improves the service life of the pouring channel;

[0010] In addition, during pouring, since a coolant flows inside the liquid cooling plate and the liquid cooling plate is installed at the bottom of the ingot mold body, the coolant can cool the ingot mold body, thereby improving the cooling rate of the nanocrystalline master alloy, ensuring the service life of the ingot mold body, and at the same time improving the preparation efficiency and product quality.

[0011] Therefore, this nanocrystalline master alloy casting system can improve the casting efficiency of the nanocrystalline master alloy, improve the product quality, and reduce the production cost.

[0012] Optionally, the refractory material filling layer includes a graphite inner lining and an electromagnetic heating layer arranged on the outer layer of the graphite inner lining; the electromagnetic heating layer is used for inductively heating the graphite inner lining to increase the temperature of the pouring channel body.

[0013] Optionally, a heat insulation layer is arranged between the graphite inner lining and the electromagnetic heating layer.

[0014] Optionally, the ingot mold device further includes an air cooling device; the air cooling device can blow cold air on the ingot mold body.

[0015] Optionally, the ingot mold device includes a frame, a steel-pouring ladle and a plurality of molds mounted on the frame, and the plurality of molds constitute the ingot mold body; the steel-pouring ladle has a runner, and a plurality of tapping openings are provided on the runner, and the plurality of tapping openings are arranged in one-to-one correspondence with the plurality of molds; in any pair of corresponding tapping openings and molds: the mold communicates with the runner through the tapping opening.

[0016] Optionally, each mold is detachably connected to the frame.

[0017] Optionally, the ingot mold device further includes a moving device and a driving device; the ingot mold body and the liquid cooling plate are both mounted on the moving device; the moving device has wheels, and the driving device is used to drive the wheels to move the moving device so that the ingot mold body can be aligned with the pouring channel body.

[0018] A method for melting a nanocrystalline master alloy, applicable to any of the above nanocrystalline master alloy melting systems, includes the following steps:

[0019] Step of melting the master alloy steel liquid: In a furnace, using pure iron, crystalline silicon, ferrosilicon boron, ferrophosphorus, ferrocolumbium and copper as raw materials, melting to obtain the master alloy steel liquid;

[0020] Casting step: Pour the obtained master alloy steel liquid into the ingot mold body through the steel-pouring channel; then the master alloy steel liquid is cooled in the ingot mold body to form a master alloy ingot.

[0021] Optionally, in the step of melting the master alloy steel liquid, the melting to obtain the master alloy steel liquid specifically includes the following steps:

[0022] (1) First-time pure iron feeding, first-time melting, first-time heat preservation, first-time slag skimming;

[0023] (2) Second-time copper and ferrosilicon boron feeding, second-time melting, second-time heat preservation, second-time slag skimming;

[0024] (3) Third-time ferrocolumbium feeding, third-time melting, third-time heat preservation, first-time slag making, third-time slag skimming;

[0025] (4) Fourth-time ferrophosphorus feeding, fourth-time melting, fourth-time heat preservation, second-time slag making, fourth-time slag skimming;

[0026] (5) Fifth-time crystalline silicon feeding, fifth-time melting, high-temperature homogenization, fifth-time slag skimming;

[0027] (6) Cooling, sixth-time heat preservation, sixth-time slag skimming;

[0028] (7) Tapping to obtain the master alloy steel liquid, and the temperature of the tapping is 1200 - 1250 °C;

[0029] Optionally, the master alloy is a FeSiBPNbMoCu-based nanocrystalline master alloy; wherein, the mass content of impurity aluminum is below 0.002%.

[0030] Preferably, for the FeSiBPNbMoCu-based nanocrystalline master alloy, by atomic percentage, Si: 0.1-15%, B: 0.1-10%, P: 0-10%, Nb: 0.1-4%, Mo: 0-4%, Cu: 0.5-2%, and the balance is Fe;

[0031] For the melting process of the master alloy steel liquid of the present invention, starting from the raw materials with the highest and cleanest component contents, aluminum is removed and slag is removed step by step. After adding the raw materials with high aluminum content, aluminum is removed by a specific slag remover to ensure that the steel liquid is pre-cleaned highly before each next step of melting. The heat absorption and heat release of the raw materials are fully utilized for the design of the steel melting temperature, the smelting rhythm is accelerated, the properties and temperature of the steel liquid are realized through high-temperature homogenization, and finally a high-clean master alloy is successfully sprayed and belted in one smelting.

[0032] Optionally, in the preparation method, the Al content in the raw material ferrophosphorus is ≥0.3 wt%, and the Al content in the ferro-niobium is ≥0.3 wt%. The method of the present invention can control the Al content in the finally obtained master alloy to be below 0.002 wt% regardless of whether the Al content in the raw materials is high or low. The method of the present invention is particularly suitable for the case where the Al content in ferrophosphorus and ferro-niobium is higher than 0.3 wt%.

[0033] Optionally, in the preparation method, by weight, the raw materials are proportioned as pure iron: crystalline silicon: ferroboron: ferrophosphorus: ferro-niobium: copper = 740:80:46:44:80:10.

[0034] Optionally, in step (1), the one-time pure iron charging is: all the pure iron is added at one time according to the furnace capacity.

[0035] Optionally, in step (1), before the one-time melting, the furnace is also baked: before starting the furnace, the bottom blowing argon pressure is given to the maximum at a power of 100 kW, and the furnace is baked for 10 min. Argon gas is passed during the baking stage to prevent the pure iron from being oxidized, and the argon gas is closed after the baking is completed.

[0036] Optionally, in step (1), the one-time melting is: melting the steel at the maximum power that the smelting furnace can reach, i.e., 1000 kW. After all the pure iron is melted, the argon valve is opened so that about 1-2 bubbles of argon emerge per second. Argon gas is blown to stir the steel liquid during the melting of the pure iron to achieve uniform temperature of the steel liquid, and the power is adjusted to the maximum to ensure the temperature required for melting the pure iron and avoid insufficient temperature.

[0037] Furthermore, the time for all the pure iron to be melted is 40-60 min.

[0038] Optionally, in step (1), the first heat preservation is as follows: continue to heat the molten steel to 1600 ± 10 °C at the maximum power of 1000 kW, then adjust the power to 520 kW, and keep it warm for 5 minutes without covering the furnace lid. Without covering the furnace lid can make the molten steel fully absorb oxygen under electromagnetic stirring, fully burn out the aluminum contained in the pure iron to form Al2O3, and reduce the Al content in the molten steel to less than 0.002 wt%.

[0039] Optionally, in step (1), the first slag removal is as follows: after the first heat preservation, remove the inclusion slag of the pure iron to make the Al content in the molten steel less than 0.002 wt%.

[0040] Optionally, in step (2), the second copper and ferroboron feeding is as follows: add copper and ferroboron in batches. The addition amount of each batch is 8 - 12 kg, preferably 10 kg, and the addition frequency is: after each batch of copper / ferroboron is melted completely, add the next batch until all copper / ferroboron is added and melted completely. When all the copper is added, the melting point of the molten steel decreases, the viscosity decreases, and the fluidity increases; when ferroboron is added, the temperature of the molten steel will drop by 50 °C, and the melting point of the molten steel will be further reduced and the fluidity will increase.

[0041] Optionally, in step (2), the second melting is as follows: adjust the power to the maximum of 1000 kW, open the argon valve wide, stir under a large flow of argon at 20 - 50 L / min until all copper / ferroboron is added and melted completely, then adjust the argon valve to make about 1 - 2 bubbles come out per second of argon, and start the second heat preservation. Each subsequent melting is carried out with large-airflow stirring, which has three functions. One is to make the granular raw materials quickly mix into the molten steel and accelerate the melting rate; the second is to use the airflow stirring to quickly exchange heat between the upper and lower layers of the molten steel in the furnace; the third is to make air enter the molten steel through argon stirring, make the molten steel rich in oxygen, and quickly remove aluminum.

[0042] Optionally, in step (2), the second heat preservation is as follows: use the endothermic effect of ferroboron melting to cool the molten steel, and adjust the power to 500 kW, keep it warm at 1580 °C ± 10 °C for 2 minutes without covering the furnace lid during the heat preservation process.

[0043] Optionally, in step (2), the second slag removal is as follows: after the heat preservation, remove the inclusion slag of the ferroboron to make the Al content in the molten steel less than 0.003 wt%.

[0044] Optionally, in step (3), the third ferrocolumbium feeding is as follows: add ferrocolumbium in batches. Adding ferrocolumbium will reduce the temperature of the molten steel by 100 °C.

[0045] Optionally, the addition amount of each batch is 8 - 12 kg, preferably 10 kg, and the addition frequency is: after each batch of ferrocolumbium is melted completely, add the next batch until all ferrocolumbium is added and melted completely.

[0046] Optionally, in step (3), the third melting is as follows: adjust the power to a maximum of 1000 kW, open the argon gas wide, stir under a large flow rate of argon gas at 20 - 50 L / min until all the ferroniobium is added and completely melted, then adjust the argon valve so that about 1 - 2 bubbles emerge per second, and start the third heat preservation.

[0047] Optionally, in step (3), the third heat preservation is as follows: utilize the endothermic effect of ferroniobium melting to cool the molten steel, and adjust the power to 480 kW, keep it at 1550 °C ± 5 °C for 5 minutes, and do not cover the furnace lid during the heat preservation process.

[0048] Optionally, in step (3), the first slag making is as follows: add a high-temperature slag making agent to absorb slag. The viscous high-temperature slag making agent adsorbs Al in the ferroniobium. The addition of ferroniobium increases the viscosity of the molten steel and makes its fluidity worse, making it difficult for the generated Al2O3 in the molten steel to float upward. Therefore, the aluminum content in the molten steel increases slightly.

[0049] Furthermore, the components of the high-temperature slag making agent are as follows: by weight, 70.5 - 76.5 wt% SiO2, 9 - 13 wt% Al2O3, 2.5 - 2.9 wt% Fe2O3, 0.15 - 0.25 wt% MgO, 1.0 - 2.6 wt% CaO, 3.0 - 6.0 wt% Na2O, 3.5 - 4.8 wt% K2O, and the particle size is 1 - 1.5 mm. The usage amount is generally 1 - 3 kg per ton of steel.

[0050] Optionally, in step (3), the third slag skimming is as follows: after the third heat preservation, skim off the inclusions slag of ferroniobium to make the aluminum content in the molten steel below 0.005 wt%.

[0051] Optionally, in step (4), the fourth ferrophosphorus feeding is as follows: add ferrophosphorus in batches. The addition of ferrophosphorus will reduce the temperature of the molten steel by 100 °C, reduce the viscosity of the molten steel, and greatly improve the fluidity of the molten steel.

[0052] Furthermore, the addition amount of each batch is 8 - 12 kg, preferably 10 kg, and the addition frequency is: after each batch of ferrophosphorus is completely melted, add the next batch until all the ferrophosphorus is added and completely melted.

[0053] Optionally, in step (4), the fourth melting is as follows: adjust the power to a maximum of 1000 kW, open the argon gas wide, stir under a large flow rate of argon gas at 20 - 50 L / min until all the ferrophosphorus is added and completely melted, then adjust the argon valve so that about 1 - 2 bubbles emerge per second, and start the fourth heat preservation.

[0054] Optionally, in step (4), the fourth heat preservation is as follows: utilize the endothermic effect of ferrophosphorus melting to cool the molten steel, and adjust the power to 320 kW, keep it at 1450 °C ± 10 °C for 2 minutes.

[0055] Optionally, in step (4), the secondary slag making is as follows: adding a low-temperature slag-making agent. The viscous low-temperature slag-making agent adsorbs Al in ferrophosphorus, further reducing the aluminum content. The aluminum content in the molten steel is below 0.004%.

[0056] Furthermore, the components of the low-temperature slag-making agent are as follows: by weight, 72.5 - 78.5 wt% SiO2, 7 - 12 wt% Al2O3, 2.5 - 3.7 wt% Fe2O3, 0.15 - 0.25 wt% MgO, 1.0 - 1.6 wt% CaO, 3.0 - 4.0 wt% Na2O, 3.5 - 4.5 wt% K2O, 1.5 - 2.5 wt% P2O5, with a particle size of 0.5 - 1 mm. The usage amount is generally 1 - 3 kg per ton of steel.

[0057] Optionally, in step (4), the fourth slag skimming is as follows: after the fourth heat preservation, skim off the inclusions slag of ferrophosphorus, so that the Al content in the molten steel is below 0.004 wt%.

[0058] Optionally, in step (5), the fifth addition of crystalline silicon is as follows: adding crystalline silicon in batches; the addition amount for each batch is 8 - 12 kg, preferably 10 kg, and the addition frequency is: after each batch of crystalline silicon is completely melted, add the next batch until all the crystalline silicon is added and completely melted. Adding metallic crystalline silicon will increase the temperature of the molten steel by 100 °C and improve the fluidity of the molten steel at the same time.

[0059] Optionally, in step (5), the fifth melting is as follows: maintain the power at 320 kW, open the argon gas valve wide, stir under a large flow rate of argon gas at 20 - 50 L / min until all the crystalline silicon is added and completely melted, and then adjust the argon gas valve so that about 1 - 2 bubbles emerge per second.

[0060] Optionally, in step (5), the high-temperature homogenization is as follows: use the exothermic effect of crystalline silicon melting to raise the temperature of the molten steel, and adjust the power to 500 kW. Conduct the fifth heat preservation at 1580 °C ± 10 °C for 5 min without covering the furnace lid during the heat preservation process. During the homogenization process of the molten steel, the molten steel is in a very good fluid state, which is conducive to the floating and removal of oxide inclusions.

[0061] Optionally, in step (5), the fifth slag skimming is as follows: after the fifth heat preservation, skim off the high-temperature inclusions slag of crystalline silicon, so that the Al content in the molten steel is below 0.003 wt%.

[0062] Optionally, in step (6), the temperature reduction is as follows: adjust the power to 0, softly blow argon with an argon gas flow rate of 3 - 10 L / min, adjust the power to 260 kW, conduct the sixth heat preservation at 1250 °C ± 10 °C for 30 min, and cover the furnace lid during the heat preservation process.

[0063] Optionally, in step (6), the six slag skimmings are as follows: after the six heat preservations are completed, the low-temperature inclusion slag of the master alloy is completely skimmed off, so that the Al content in the molten steel is below 0.002 wt%, and then wait for tapping.

[0064] Optionally, in step (7), the tapping temperature is 1200 - 1250 °C.

[0065] Compared with the prior art, the present invention has at least the following beneficial effects:

[0066] In the casting system provided by the present invention, the pouring channel is provided with a heatable graphite lining. The electromagnetic heating layer can be heated to 1000 °C within 30 seconds. The molten steel in the pouring channel body is heated simultaneously by the heat supplement of the graphite lining and the electromagnetic induction heating of the molten steel, which can greatly improve the heating efficiency and heating stability. When there is no molten steel, the pouring channel can be maintained at a relatively high temperature through the radiative heat supplement of the graphite lining, enabling the transmission of low-temperature molten steel. The tapping temperature can be controlled at 1200 - 1250 °C for low-temperature pouring, reducing the burning loss and high-temperature oxidation of the molten steel. The obtained master alloy grains are finer and more uniform, and the strip-making effect is better.

[0067] A highly clean glass lining is arranged on the inner layer of the pouring channel: Glass is not wetted by molten steel, which can greatly improve the flow rate of molten steel, reduce oxidation and temperature drop. Glass has good high-temperature thermal stability and does not react with molten steel to pollute the molten steel. After pouring, the glass will form cracks when cooled, which is easy to clean the pouring channel. The glass residues and residual steel after cleaning can be remelted in the furnace. The glass can form protective slag after melting, and the yield of molten steel is high. After each pouring, only the glass layer needs to be cleaned, and a small amount of plastic material is used to fix the new glass lining to pour steel again, which greatly reduces the wear of the refractory material of the pouring channel, i.e., the runner, and improves the service life of the pouring channel, enabling highly clean transmission of molten steel.

[0068] The casting system provided by the present invention is combined with a low-temperature pouring process and is used in conjunction with a rapid-cooling ingot mold device. The liquid cooling plate in the ingot mold device is installed at the bottom of the ingot mold body, and the coolant flows inside the liquid cooling plate; the air-cooling device can discharge cold air to cool the surface of the master alloy. In this rapid-cooling nanocrystalline ingot mold device, when the high-temperature liquid metal molten steel is poured into the mold, since the coolant flows inside the liquid cooling plate and the liquid cooling plate is installed at the bottom of the ingot mold body, the coolant can cool the ingot mold body; when the high-temperature liquid metal solidifies the shell, the air-cooling device can be started to discharge cold air to the surface of the master alloy for further cooling. Rapid cooling can make the grain size of the master alloy uniform and the master alloy easy to break.

[0069] The nanocrystalline master alloy casting system of the present invention can improve the efficiency of nanocrystalline master alloy casting, improve the product quality, and reduce the production cost.

[0070] In addition, the smelting process in the melting and casting method of the present invention can prepare an FeSiBPNbMoCu-based nanocrystalline master alloy steel liquid with the mass content of impurity aluminum below 0.002%. Combining with the subsequent casting step, a high-quality master alloy steel ingot can be obtained, with uniform grain size and easy to be broken.

[0071] The master alloy steel ingot prepared by the melting system and method of the present invention is used for producing nanocrystalline thin strips, which can realize the production of wide-width ultra-thin nanocrystalline strips, with stable product performance and high output. Brief Description of the Drawings

[0072] The attached drawings of the specification, which form a part of this application, are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. Among them:

[0073] Figure 1 It is a schematic diagram of the relationship between the structures in the nanocrystalline master alloy melting and casting system provided by the embodiment of the present invention;

[0074] Figure 2 It is a partial structural schematic diagram of the ingot mold device in the nanocrystalline master alloy melting and casting system provided by the embodiment of the present invention;

[0075] Figure 3 It is a side view of the ingot mold device in the nanocrystalline master alloy melting and casting system provided by the embodiment of the present invention;

[0076] Figure 4 It is a structural schematic diagram of the steel pouring channel in the nanocrystalline master alloy melting and casting system provided by the embodiment of the present invention;

[0077] Figure 5 It is a schematic diagram of the positions of the graphite lining and the electromagnetic heating layer in the steel pouring channel of the nanocrystalline master alloy melting and casting system provided by the embodiment of the present invention;

[0078] Figure 6 It is a flow chart of the nanocrystalline master alloy melting and casting method provided by the embodiment of the present invention;

[0079] Figure 7 It is a micrograph of the master alloy steel ingot formed by the nanocrystalline master alloy melting and casting method provided by the embodiment of the present invention.

[0080] Reference Signs: 1 - Furnace; 2 - Steel Pouring Channel; 3 - Ingot Mold Device; 4 - Ingot Mold Body; 5 - Outer Shell; 6 - Refractory Material Filling Layer; 7 - Glass Lining; 8 - Pouring Channel Body; 9 - Liquid Cooling Plate; 10 - Graphite Lining; 11 - Electromagnetic Heating Layer; 12 - Heat Preservation Layer; 13 - Frame; 14 - Steel Pouring Tray; 15 - Mold; 16 - Runner; 17 - Tapping Port; 18 - Trolley; 19 - Workbench; 20 - Roller. Detailed Embodiments

[0081] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present invention rather than a limitation thereof. In fact, those skilled in the art will appreciate that modifications and variations can be made to the present invention without departing from the scope or spirit thereof. For example, features shown or described as part of one embodiment can be used in another embodiment to yield yet another embodiment. Accordingly, it is intended that the present invention cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0082] In the description of the present invention, the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention. The terms "connected", "connected to", and "disposed" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0083] Figure 1 Schematic diagram of the relationship between the structures in the nanocrystalline master alloy casting system provided by an embodiment of the present invention; Figure 2 Partial structural schematic diagram of the ingot mold device in the nanocrystalline master alloy casting system provided by an embodiment of the present invention; Figure 3 Side view of the ingot mold device in the nanocrystalline master alloy casting system provided by an embodiment of the present invention; Figure 4 Schematic diagram of the structure of the steel pouring channel in the nanocrystalline master alloy casting system provided by an embodiment of the present invention; As Figures 1-4 shown, an embodiment of the present invention provides a nanocrystalline master alloy casting system, including: a melting furnace 1, a steel pouring channel 2, and an ingot mold device 3; the melting furnace 1 is used for melting molten steel, the steel pouring channel 2 is used for pouring the molten steel prepared by the melting furnace 1 into the ingot mold device 3, and the ingot mold device 3 includes an ingot mold body 4. The ingot mold body 4 is used for accommodating the molten steel poured by the steel pouring channel 2 so that the molten steel cools in the ingot mold body 4; the steel pouring channel 2 sequentially includes a housing 5, a refractory material filling layer 6, and a glass inner lining 7 from the outside to the inside; the inner cavity of the glass inner lining 7 constitutes a pouring channel body 8, and the pouring channel body 8 is used for flowing molten steel; the ingot mold device 3 further includes a liquid cooling plate 9, and the liquid cooling plate 9 is installed at the bottom of the ingot mold body 4, and a coolant flows inside the liquid cooling plate 9.

[0084] In this embodiment, when molten steel is poured from the melting furnace 1 into the ingot mold body 4 through the pouring channel 2, since the inner cavity of the refractory material filling layer 6 is provided with a glass lining 7, the surface of the glass material is relatively smooth and non-wetting with the molten steel, which can improve the flow rate of the molten steel. Moreover, the glass has good thermal stability and low thermal conductivity at high temperatures, which can reduce oxidation and temperature drop and is not likely to react with the molten steel to contaminate it. After pouring, the glass material cools and undergoes a polymorphic transformation to form cracks, which is easy to clean the surface of the pouring channel body 8. The cleaned glass residues and residual steel can be remelted in the furnace, and the melted glass can form a protective slag, with a high molten steel yield. After each pouring, only the glass lining 7 needs to be cleaned, and a small amount of plastic material is used to fix the new glass lining 7 to pour steel again, greatly reducing the wear of the pouring channel body 8 and improving the service life of the pouring channel;

[0085] During pouring, since the liquid cooling plate 9 circulates coolant inside and the liquid cooling plate 9 is installed at the bottom of the ingot mold body 4, the coolant can cool the ingot mold body 4, thereby increasing the cooling rate of the nanocrystalline master alloy, ensuring the service life of the ingot mold body 4, and at the same time improving the preparation efficiency and product quality.

[0086] Therefore, this nanocrystalline master alloy melting and casting system can improve the efficiency of nanocrystalline master alloy melting and casting, enhance product quality, and reduce production costs.

[0087] Figure 5 It is a schematic diagram of the positions of the graphite lining and the electromagnetic heating layer in the pouring channel of the nanocrystalline master alloy melting and casting system provided by the embodiment of the present invention. As Figure 5 shown, as an optional embodiment, the refractory material filling layer 6 includes a graphite lining 10 and an electromagnetic heating layer 11 provided on the outer layer of the graphite lining 10; the electromagnetic heating layer 11 is used to inductively heat the graphite lining 10 to increase the temperature of the pouring channel body 8.

[0088] In this embodiment, the setting of the electromagnetic heating layer 11 can quickly heat the graphite lining 10. The induction heating method can heat the graphite heat supplement layer to 1000 degrees within 30 seconds, thus greatly improving the heating efficiency and heating stability. Before pouring, turn on the electromagnetic induction heating device, and the graphite lining 10 is quickly heated through electromagnetic induction. The graphite lining 10 preheats the adjacent refractory materials before pouring through radiation and conduction. Since the graphite heats up very quickly, the pouring channel 2 can be preheated to the designed pouring temperature of the pouring channel in a very short time.

[0089] Refer to Figure 5 As an optional embodiment, a heat insulation layer 12 is provided between the graphite lining 10 and the battery heating layer.

[0090] In this embodiment, the setting of the heat insulation layer 12 can further prevent the temperature loss of the graphite lining 10 after being heated, thus more effectively ensuring the heating efficiency.

[0091] As an alternative embodiment, the ingot mold device 3 further includes an air cooling device; the air cooling device can blow cold air onto the ingot mold body 4.

[0092] In this embodiment, when the high-temperature molten steel cools and solidifies a shell in the ingot mold body 4, the air cooling device can be started to discharge cold air onto the surface of the master alloy, further cooling it and further improving the production efficiency.

[0093] Refer to Figure 2 and Figure 3 As an alternative embodiment, the ingot mold device 3 includes a frame 13, a steel-pouring ladle 14 and a plurality of molds 15 mounted on the frame 13. The plurality of molds 15 constitute the ingot mold body 4; the steel-pouring ladle 14 has a runner 16, and a plurality of tapping openings 17 are provided on the runner 16. The plurality of tapping openings 17 are arranged in one-to-one correspondence with the plurality of molds 15; in any pair of corresponding tapping openings 17 and molds 15: the mold 15 is communicated with the runner 16 through the tapping opening 17.

[0094] Among them, the liquid cooling plate 9 may have multiple rows of cooling pipelines for circulating the coolant. The extending direction of the cooling pipelines is perpendicular to the arrangement direction of each mold, and the two cooperate with each other to form a grid structure. The rapid cooling of the mold can be achieved through the cooling pipelines. Due to the uneven cooling rate of the master alloy in the grid runner and grid position, local stress concentration will be caused, and the nanocrystalline master alloy containing more than 10% of metalloid elements belongs to a brittle alloy. Therefore, in the case of rapid cooling of the nanocrystalline master alloy, it can be naturally split into small chocolate-like pieces under the action of stress through the grid structure, which is more convenient for the demolding of the master alloy and subsequent collection, thus further improving the production efficiency.

[0095] In this embodiment, since the multiple tapping openings 17 of the runner 16 are arranged in one-to-one correspondence with the multiple molds 15, when pouring the molten steel, only need to pour the molten steel into the runner 16 first, and then the molten steel can flow into different molds 15 from different tapping openings 17 respectively, so as to realize the rapid pouring of multiple molds 15 and further improve the pouring efficiency.

[0096] As an alternative embodiment, each mold 15 and the frame 13 are detachably connected.

[0097] In this embodiment, in the way that the mold 15 and the frame 13 are detachably connected, if a certain mold 15 is damaged, the damaged mold 15 can be separately disassembled and replaced, without the need to replace all the molds 15 as a whole. While improving the operation convenience, it also saves the production cost.

[0098] Continue to refer toFigure 3 , as an alternative embodiment, the ingot mold device 3 further includes a moving device and a driving device; both the ingot mold body 4 and the liquid cooling plate 9 are installed on the moving device; the moving device has rollers 20, and the driving device is used to drive the rollers 20 to move the moving device, so that the ingot mold body 4 can be aligned with the pouring channel body 8.

[0099] In this embodiment, as Figure 3 shown, the moving device can be a trolley 18. The trolley 18 has a workbench 19. The workbench 19 has a hollow cavity. The liquid cooling plate 9 is installed in the hollow cavity. The ingot mold body 4 is installed on the surface of the workbench 19, and the rollers 20 are located at the bottom of the workbench 19. Such a setting can facilitate the alignment of the ingot mold body 4 with the pouring channel body 8, further increasing the convenience during pouring and improving the production efficiency.

[0100] Figure 6 is a flowchart of the nanocrystalline master alloy melting and casting method provided by the embodiment of the present invention. As Figure 6 shown, the embodiment of the present invention also provides a nanocrystalline master alloy melting and casting method, which is applicable to any of the above nanocrystalline master alloy melting and casting systems, and includes the following steps:

[0101] Step S100: In a furnace, use pure iron, crystalline silicon, ferroboron, ferrophosphorus, ferroniobium and copper as raw materials to prepare master alloy steel liquid;

[0102] Step S200: Pour the prepared steel liquid into the ingot mold body through a steel pouring channel; the steel liquid is cooled in the ingot mold body to form a master alloy steel ingot.

[0103] As an alternative embodiment, the preparation of the master alloy steel liquid specifically includes the following steps:

[0104] Step S101: First-time pure iron feeding, first-time melting, first-time heat preservation, first-time slag removal;

[0105] Step S102: Second-time copper and ferroboron feeding, second-time melting, second-time heat preservation, second-time slag removal;

[0106] Step S103: Third-time ferroniobium feeding, third-time melting, third-time heat preservation, first-time slag making, third-time slag removal;

[0107] Step S104: Fourth-time ferrophosphorus feeding, fourth-time melting, fourth-time heat preservation, second-time slag making, fourth-time slag removal;

[0108] Step S105: Fifth-time crystalline silicon feeding, fifth-time melting, high-temperature homogenization, fifth-time slag removal;

[0109] Step S106: Cooling down, sixth-time heat preservation, sixth-time slag removal;

[0110] Step S107: Tapping.

[0111] The melting and casting method of the present invention will be described and explained below through specific examples and comparative examples.

[0112] In the following examples, for the high-phosphorus and high-niobium nanocrystalline components, based on the proportion of each component (assuming that the components of 2000 kg of nanocrystalline alloy are proportioned as iron: crystalline silicon: ferrosilicon boron: ferrophosphorus: ferroniobium: copper = 1480:160:92:88:160:20) and the impurity content (the aluminum content in the nanocrystalline raw materials is respectively: pure iron (0.0022%), crystalline silicon (0.03%), ferrosilicon boron (0.014%), ferrophosphorus (0.32%), ferroniobium (0.3%), copper (0.014%); the Al content of each component is approximately: pure iron (0.03256): crystalline silicon (0.048): ferrosilicon boron (0.0128): ferrophosphorus (0.2816): ferroniobium (0.48): copper (0)), making full use of the melting points of each component (the melting points of each component: pure iron (1534 °C), crystalline silicon (1410 °C), ferrosilicon boron (1500 °C), ferrophosphorus (1200 °C), ferroniobium (1560 °C), copper (1080 °C)) and the heat absorption and release after addition, optimizing the feeding order, using high-temperature and low-temperature slag formers in combination, removing aluminum inclusions in each component step by step, and at the same time performing high-temperature melt homogenization treatment, so that the obtained FeSiBPNbMoCu-based nanocrystalline master alloy is an ultra-low aluminum, high-phosphorus and high-niobium nanocrystalline master alloy steel liquid, and the obtained master alloy steel liquid is Fe 77 Si 12 B6P2Nb2Cu1, where the mass content of aluminum is below 0.002%, the phosphorus and niobium contents are high, and the atomic percentages are both 2%; thereby reducing the impurities in the steel liquid and improving the production efficiency and product quality.

[0113] Example 1

[0114] A melting and casting method for an ultra-low aluminum nanocrystalline master alloy. Assuming that the components of 2000 kg of nanocrystalline alloy are proportioned as pure iron: crystalline silicon: ferrosilicon boron: ferrophosphorus: ferroniobium: copper = 1480:160:92:88:160:20, the specific steps are as follows:

[0115] (1) Add all the pure iron at once according to the furnace capacity for the first pure iron charging; then, before starting the furnace, set the bottom blowing argon pressure to the maximum and bake the furnace at a power of 100 kW for 10 min. During the baking stage, pass argon to prevent the pure iron from being oxidized, and close the argon after baking; then melt the steel at the maximum power that the smelting furnace can reach, which is 1000 kW. After all the pure iron has melted, open the argon valve so that about 1 - 2 bubbles emerge per second. The time for all the pure iron to melt is about 50 min; continue to heat the molten steel to 1600 ± 10 °C at the maximum power of 1000 kW, then adjust the power to 520 kW for the first heat preservation for 5 min. Do not cover the furnace lid during the heat preservation process, so that the molten steel can fully absorb oxygen under electromagnetic stirring and fully burn out the aluminum contained in the pure iron to form Al2O3; after the first heat preservation, perform the first slag removal to completely remove the inclusions slag of the pure iron, so that the Al content in the molten steel is below 0.002 wt%.

[0116] (2) Then, add all the copper and all the ferroboron in sequence for the second copper and ferroboron charging. Add the copper in batches. After each batch of 10 kg of copper has melted, add the next batch. When all the copper is added, due to the small amount of copper and high temperature, it melts quickly, the melting point of the molten steel decreases, the viscosity decreases, and the fluidity increases; add the ferroboron in batches. After each batch of 10 kg of ferroboron has melted, add the next batch. When adding ferroboron, the molten steel temperature will drop by 50 °C, and further reduce the melting point of the molten steel and increase the fluidity. Adjust the power to the maximum of 1000 kW to ensure smooth melting during the addition of ferroboron; turn up the argon and stir at a large flow rate of 20 - 50 L / min until all the copper / ferroboron is added and melted completely. Then adjust the argon valve so that about 1 - 2 bubbles emerge per second, and start the second heat preservation. Use the heat absorption effect of the melting of ferroboron to cool the molten steel, and adjust the power to 500 kW. Keep it at 1580 °C ± 10 °C for 2 min. Do not cover the furnace lid during the heat preservation process; then perform the second slag removal to completely remove the inclusions slag of the ferroboron, so that the Al content in the molten steel is below 0.003 wt%.

[0117] (3) Next, carry out niobium iron feeding three times. Specifically, add niobium iron in batches, 10 kg of niobium iron each time. After it melts completely, add the next batch until all the niobium iron is added and melted completely; the addition of niobium iron will reduce the temperature of the molten steel by 100 °C. Therefore, when melting niobium iron three times, the power is adjusted to a maximum of 1000 kW, and the argon gas is turned up. Stir under a large flow rate of argon gas at 20 - 50 L / min until all the niobium iron is added and melted completely. Then adjust the argon valve so that about 1 - 2 bubbles emerge per second, and start the three - time heat preservation; utilize the endothermic effect of niobium iron melting to cool the molten steel, and adjust the power to 480 kW. Keep it warm at 1550 °C ± 5 °C for 5 min without covering the furnace lid during the heat - preservation process; then add a high - temperature slag - making agent for slag - making and slag - absorbing once. Among them, the components of the high - temperature slag - making agent are as follows: by weight, 76 wt% SiO2, 11.5 wt% Al2O3, 2.6 wt% Fe2O3, 0.2 wt% MgO, 1.5 wt% CaO, 3.8 wt% Na2O, 4.4 wt% K2O, and the particle size is 1 - 1.5 mm; the viscous high - temperature slag - making agent adsorbs Al in the niobium iron. However, due to the addition of niobium iron, the viscosity of the molten steel increases and the fluidity becomes worse. Therefore, it is difficult for the generated Al2O3 in the molten steel to float up, and the aluminum content in the molten steel increases slightly; finally, carry out slag - skimming three times to completely remove the inclusion slag of niobium iron, so that the aluminum content in the molten steel is below 0.005 wt%.

[0118] (4) Next, carry out ferrophosphorus feeding four times. Specifically, add ferrophosphorus in batches, 10 kg of ferrophosphorus each time. After it melts completely, add the next batch until all the ferrophosphorus is added and melted completely; the addition of ferrophosphorus will reduce the viscosity of the molten steel, greatly improve the fluidity, and at the same time reduce the temperature of the molten steel by 100 degrees. According to the melting point of ferrophosphorus, the power is adjusted to a maximum of 1000 kW, and the argon gas is turned up. Stir under a large flow rate of argon gas at 20 - 50 L / min until all the ferrophosphorus is added and melted completely. Then adjust the argon valve so that about 1 - 2 bubbles emerge per second, and start the four - time heat preservation; utilize the endothermic effect of ferrophosphorus melting to cool the molten steel, and adjust the power to 320 kW. Keep it warm at 1450 °C ± 10 °C for 2 min; then add a low - temperature slag - making agent for secondary slag - making. Among them, the components of the low - temperature slag - making agent are as follows: by weight, 77 wt% SiO2, 10 wt% Al2O3, 2.5 wt% Fe2O3, 0.2 wt% MgO, 1.2 wt% CaO, 3.1 wt% Na2O, 4 wt% K2O, 2 wt% P2O5, and the particle size is 0.5 - 1 mm; the viscous low - temperature slag - making agent adsorbs Al in the ferrophosphorus, further reducing the aluminum content; finally, carry out slag - skimming four times to completely remove the inclusion slag of ferrophosphorus, so that the Al content in the molten steel is below 0.004 wt%.

[0119] (5) Next, perform five batches of crystallized silicon fabric addition with power cut, and add crystallized silicon in batches; the addition amount for each batch is 8 - 12 kg, preferably 10 kg, and the addition frequency is: after each batch of crystallized silicon is completely melted, add the next batch until all crystallized silicon is added and completely melted. The addition of metallic crystallized silicon will improve the fluidity of the molten steel and increase the temperature of the molten steel by 100 °C. Maintain the power at 320 kW, open the argon gas valve wide, and stir under a large flow of argon gas at 50 - 200 L / min until all crystallized silicon is added and completely melted. Then adjust the argon gas valve so that about 1 - 2 bubbles emerge per second; afterwards, perform high-temperature homogenization, that is, use the exothermic effect of crystallized silicon melting to raise the temperature of the molten steel, and adjust the power to 500 kW, and perform five heat preservations at 1580 °C ± 10 °C for 5 min each. Do not cover the furnace lid during the heat preservation process. Since the molten steel is in the process of homogenization and at the same time the molten steel is in a very good fluid state, it is conducive to the floating and removal of oxide inclusions; finally, perform five slag removals to completely remove the high-temperature inclusions slag of crystallized silicon, so that the Al content in the molten steel is below 0.003 wt%.

[0120] (6) Next, lower the temperature, adjust the power to 0, perform soft argon blowing with an argon gas flow rate of 3 - 10 L / min, adjust the power to 260 kW, and perform six heat preservations at 1250 °C ± 10 °C for 30 min each. Cover the furnace lid during the heat preservation process. After the six heat preservations are completed, perform six slag removals to completely remove the low-temperature inclusions slag of the master alloy, so that the Al content in the molten steel is below 0.002 wt%, and wait for tapping.

[0121] (7) Finally, tap the molten steel, and the tapping temperature is about 1250 °C. The Al content in the molten steel is 0.0015 wt%.

[0122] (8) Pour the obtained molten steel into the ingot mold body through the casting channel; the molten steel is cooled in the ingot mold body to obtain the master alloy steel ingot.

[0123] Figure 7 This is the micrograph of the master alloy steel ingot formed by the nanocrystalline master alloy melting and casting method provided in the embodiment of the present invention. The microstructure of the master alloy steel ingot can be referred to Figure 7 .

[0124] The master alloy steel ingot obtained by the melting and casting method of the present invention has uniform grain size, no composition segregation, and is easy to break.

[0125] Example 2

[0126] A melting and casting method of an ultra-low aluminum nanocrystalline master alloy, which is different from Example 1 in that in step (3), the components of the high-temperature slag former are as follows: by weight, SiO2 76.5 wt%, Al2O3 11 wt%, Fe2O3 2.5 wt%, MgO 0.25 wt%, CaO 1.6 wt%, Na2O 4.0 wt%, K2O 4.15 wt%.

[0127] For the remaining settings, they are the same as those in Example 1.

[0128] The Al content in the molten steel obtained in step (7) is 0.0016 wt%.

[0129] The mother alloy steel ingot obtained by the melting and casting method of the present invention has uniform grain size, no composition segregation, and is easy to break.

[0130] Example 3

[0131] A melting and casting method of an ultra-low aluminum nanocrystalline master alloy, different from Example 1 in that in step (3), the components of the high-temperature slag-making agent are as follows: by weight, SiO2 75.5 wt%, Al2O3 12 wt%, Fe2O3 2.6 wt%, MgO 0.2 wt%, CaO 1.5 wt%, Na2O 3.8 wt%, K2O 4.4 wt%.

[0132] For the remaining settings, they are the same as those in Example 1.

[0133] The Al content in the molten steel obtained in step (7) is 0.0017 wt%.

[0134] The mother alloy steel ingot obtained by the melting and casting method of the present invention has uniform grain size, no composition segregation, and is easy to break.

[0135] Example 4

[0136] A melting and casting method of an ultra-low aluminum nanocrystalline master alloy, different from Example 1 in that in step (4), the components of the low-temperature slag-making agent are as follows: by weight, SiO2 78.5 wt%, Al2O3 9.0 wt%, Fe2O3 2.55 wt%, MgO 0.15 wt%, CaO 1.3 wt%, Na2O 3.2 wt%, K2O 3.7 wt%, P2O5 1.6 wt%.

[0137] For the remaining settings, they are the same as those in Example 1.

[0138] The Al content in the molten steel obtained in step (7) is 0.0018 wt%.

[0139] The mother alloy steel ingot obtained by the melting and casting method of the present invention has uniform grain size, no composition segregation, and is easy to break.

[0140] Example 5

[0141] A method for melting and casting an ultra-low aluminum nanocrystalline master alloy, which is different from Example 1 in that in step (4), the components of the low-temperature slag-making agent are as follows: by weight, SiO2 75.5wt%, Al2O3 10wt%, Fe2O3 2.6wt%, MgO 0.2wt%, CaO 1.5wt%, Na2O 3.5wt%, K2O 4.2wt%, P2O5 2.5wt%.

[0142] For the rest of the settings, they are the same as those in Example 1.

[0143] The Al content in the molten steel obtained in step (7) is 0.0017wt%.

[0144] The master alloy steel ingot obtained by the melting and casting method of the present invention has uniform grain size, no segregation in composition, and is easy to break.

[0145] Comparative Example 1

[0146] A method for melting and casting a nanocrystalline master alloy, which is different from Example 1 in that step (2) is not included, and the copper and ferroboron cloth in the original step (2) are changed to be cloth in step (3) for feeding.

[0147] For the rest of the settings, they are the same as those in Example 1.

[0148] The Al content in the molten steel obtained in step (7) is 0.0025wt%.

[0149] Comparative Example 2

[0150] A method for melting and casting a nanocrystalline master alloy, which is different from Example 1 in that the high-temperature homogenization process in step (5) is not included, and after stirring under a large flow of argon, step (6) is directly carried out.

[0151] For the rest of the settings, they are the same as those in Example 1.

[0152] The Al content in the molten steel obtained in step (7) is 0.0026wt%.

[0153] Comparative Example 3

[0154] A method for melting and casting a nanocrystalline master alloy, which is different from Example 1 in that a high-temperature slag-making agent is not used in step (3).

[0155] For the rest of the settings, they are the same as those in Example 1.

[0156] The Al content in the molten steel obtained in step (7) is 0.0035wt%.

[0157] Comparative Example 4

[0158] A method for melting and casting a nanocrystalline master alloy, which is different from Example 1 in that a low-temperature slag-making agent is not used in step (4).

[0159] All other settings are the same as those in Embodiment 1.

[0160] The Al content in the molten steel obtained in step (7) is 0.0031 wt%.

[0161] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A nanocrystalline master alloy melting and casting system, characterized in that, Including: A melting furnace, a steel pouring channel, and an ingot mold device; The melting furnace is used for melting molten steel, the steel pouring channel is used for pouring the molten steel melted by the melting furnace into the ingot mold device, the ingot mold device includes an ingot mold body, and the ingot mold body is used for accommodating the molten steel poured by the steel pouring channel to cool the molten steel in the ingot mold body; The steel pouring channel successively includes a housing, a refractory material filling layer, and a glass inner lining from outside to inside; the inner cavity of the glass inner lining constitutes the pouring channel body, and the pouring channel body is used for flowing molten steel; The ingot mold device further includes a liquid cooling plate, the liquid cooling plate is installed at the bottom of the ingot mold body, and coolant flows inside the liquid cooling plate; The refractory material filling layer includes a graphite inner lining and an electromagnetic heating layer arranged on the outer layer of the graphite inner lining; The electromagnetic heating layer is used for inductively heating the graphite inner lining to increase the temperature of the pouring channel body; A heat insulation layer is arranged between the graphite inner lining and the electromagnetic heating layer; The ingot mold device further includes an air cooling device; The air cooling device can blow cold air to the ingot mold body; The ingot mold device includes a frame, a steel pouring pan and a plurality of molds installed on the frame, and the plurality of molds constitute the ingot mold body; The steel pouring pan has a flow channel, and a plurality of tapping openings are arranged on the flow channel, and the plurality of tapping openings are arranged in one-to-one correspondence with the plurality of molds; In any pair of corresponding tapping opening and mold: the mold is communicated with the flow channel through the tapping opening.

2. The nanocrystalline master alloy melting and casting system according to claim 1, characterized in that Each mold is detachably connected to the frame.

3. The nanocrystalline master alloy melting and casting system according to any one of claims 1-2, characterized in that The ingot mold device further includes a moving device and a driving device; The ingot mold body and the liquid cooling plate are both installed on the moving device; The moving device has rollers, and the driving device is used for driving the rollers to move the moving device so that the ingot mold body can be aligned with the pouring channel body.

4. A method for melting and casting a nanocrystalline master alloy, applicable to the nanocrystalline master alloy melting and casting system described in any one of claims 1-3, characterized in that, Including the following steps: Step of melting master alloy steel liquid: In the melting furnace, using pure iron, crystalline silicon, ferroboron, ferrophosphorus, ferrocolumbium and copper as raw materials, melting to obtain master alloy steel liquid; Casting step: Pouring the obtained master alloy steel liquid into the ingot mold body through the steel pouring channel, and then cooling the master alloy steel liquid in the ingot mold body to form a master alloy steel ingot.

5. The method for melting and casting the nanocrystalline master alloy according to claim 4, characterized in that, In the step of melting master alloy steel liquid, the steps of melting to obtain master alloy steel liquid successively include the following steps: (1) First pure iron feeding, first melting, first heat preservation, first slag skimming; (2) Second copper and ferroboron feeding, second melting, second heat preservation, second slag skimming; (3) Third ferrocolumbium feeding, third melting, third heat preservation, first slag making, third slag skimming; (4) Fourth ferrophosphorus feeding, fourth melting, fourth heat preservation, second slag making, fourth slag skimming; (5) Fifth crystalline silicon feeding, fifth melting, high-temperature homogenization, fifth slag skimming; (6) Temperature reduction, sixth heat preservation, sixth slag skimming; (7) Tapping to obtain master alloy steel liquid, and the tapping temperature is 1200 - 1250 °C; The master alloy steel liquid is a FeSiBPNbMoCu-based nanocrystalline master alloy; among them, the mass content of impurity aluminum is below 0.002%.

6. The method for melting and casting the nanocrystalline master alloy according to claim 5, wherein The FeSiBPNbMoCu-based nanocrystalline master alloy, by atomic percentage, contains Si: 0.1 - 15%, B: 0.1 - 10%, P: 0 - 10%, Nb: 0.1 - 4%, Mo: 0 - 4%, Cu: 0.5 - 2%, and the balance is Fe.

7. The method for melting and casting the nanocrystalline master alloy according to claim 5, characterized in that In the step (1), The primary pure iron charging is as follows: all the pure iron is added at one time according to the furnace capacity; Before the primary melting, the furnace is also baked: before starting the furnace, the bottom blowing argon pressure is given to the maximum, and the furnace is baked for 10 min with a power of 100 kW; The primary melting is as follows: melting the steel at the maximum power that the smelting furnace can reach, i.e., 1000 kW. After all the pure iron is melted, open the argon valve so that 1 - 2 bubbles emerge per second; The time for all the pure iron to be completely melted is 40 - 60 min; The primary heat preservation is as follows: continue to heat the molten steel to 1600 ± 10 °C at the maximum power of 1000 kW, then adjust the power to 520 kW and keep it warm for 5 min without covering the furnace lid during the heat preservation process; The primary slag skimming is as follows: after the primary heat preservation ends, skim off the inclusions slag of the pure iron so that the Al content in the molten steel is below 0.002 wt %.

8. The method for melting and casting the nanocrystalline master alloy according to claim 5, characterized in that In the step (2), The secondary copper and ferroboron charging is as follows: copper and ferroboron are added in batches; The addition amount for each batch is 8 - 12 kg, and the addition frequency is: after each batch of copper / ferroboron is completely melted, add the next batch until all the copper / ferroboron is added and completely melted; The secondary melting is as follows: adjust the power to the maximum of 1000 kW, open the argon valve wide, stir under a large flow of argon until all the copper / ferroboron is added and completely melted, then adjust the argon valve so that 1 - 2 bubbles emerge per second, and start the secondary heat preservation; The secondary heat preservation is as follows: utilize the heat absorption effect of ferroboron melting to cool the molten steel, and adjust the power to 500 kW, keep it warm at 1580 °C ± 10 °C for 2 min without covering the furnace lid during the heat preservation process; The secondary slag skimming is as follows: after the heat preservation ends, skim off the inclusions slag of ferroboron so that the Al content in the molten steel is below 0.003 wt %.

9. The method for melting and casting the nanocrystalline master alloy according to claim 5, characterized in that In the step (3), The tertiary ferroniobium charging is as follows: ferroniobium is added in batches; The addition amount for each batch is 8 - 12 kg, and the addition frequency is: after each batch of ferroniobium is completely melted, add the next batch until all the ferroniobium is added and completely melted; The tertiary melting is as follows: adjust the power to the maximum of 1000 kW, open the argon valve wide, stir under a large flow of argon until all the ferroniobium is added and completely melted, then adjust the argon valve so that 1 - 2 bubbles emerge per second, and start the tertiary heat preservation; The tertiary heat preservation is as follows: utilize the heat absorption effect of ferroniobium melting to cool the molten steel, and adjust the power to 480 kW, keep it warm at 1550 °C ± 5 °C for 5 min without covering the furnace lid during the heat preservation process; The primary slag making is as follows: add a high-temperature slag-making agent to absorb the slag; The components of the high-temperature slag-making agent are as follows: by weight, 70.5 - 76.5 wt% SiO2, 9 - 13 wt% Al2O3, 2.5 - 2.9 wt% Fe2O3, 0.15 - 0.25 wt% MgO, 1.0 - 2.6 wt% CaO, 3.0 - 6.0 wt% Na2O, 3.5 - 4.8 wt% K2O, and the particle size is 1 - 1.5 mm; The third slag removal is: after the third heat preservation is completed, remove the inclusion slag of ferroniobium completely, so that the Al content in the molten steel is below 0.005 wt%.

10. The method for melting and casting the nanocrystalline master alloy according to claim 5, characterized in that In the step (4), The fourth ferrophosphorus feeding is: adding ferrophosphorus in batches; The addition amount of each batch is 8 - 12 kg, and the addition frequency is: after each batch of ferrophosphorus is completely melted, add the next batch until all ferrophosphorus is added and completely melted; The fourth melting is: adjust the power to a maximum of 1000 kW, open the argon gas valve wide, stir under a large flow of argon gas until all ferrophosphorus is added and completely melted, then adjust the argon gas valve so that 1 - 2 bubbles emerge per second, and start the fourth heat preservation; The fourth heat preservation is: use the endothermic effect of ferrophosphorus melting to cool the molten steel, and adjust the power to 320 kW, keep it at 1450 °C ± 10 °C for 2 minutes, and do not cover the furnace lid during the heat preservation process; The second slag making is: adding a low-temperature slag-making agent; The components of the low-temperature slag-making agent are as follows: by weight, 72.5 - 78.5 wt% SiO2, 7 - 12 wt% Al2O3, 2.5 - 3.7 wt% Fe2O3, 0.15 - 0.25 wt% MgO, 1.0 - 1.6 wt% CaO, 3.0 - 4.0 wt% Na2O, 3.5 - 4.5 wt% K2O, 1.5 - 2.5 wt% P2O5, and the particle size is 0.5 - 1 mm; The fourth slag removal is: after the fourth heat preservation is completed, remove the inclusion slag of ferrophosphorus completely, so that the Al content in the molten steel is below 0.004 wt%.

11. The method for melting and casting the nanocrystalline master alloy according to claim 5, characterized in that In the step (5), The fifth crystalline silicon feeding is: adding crystalline silicon in batches; The addition amount of each batch is 8 - 12 kg, and the addition frequency is: after each batch of crystalline silicon is completely melted, add the next batch until all crystalline silicon is added and completely melted; The fifth melting is: keep the power at 320 kW, open the argon gas valve wide, stir under a large flow of argon gas until all crystalline silicon is added and completely melted, then adjust the argon gas valve so that 1 - 2 bubbles emerge per second; The high-temperature homogenization is: use the exothermic effect of crystalline silicon melting to heat up the molten steel, and adjust the power to 500 kW, carry out the fifth heat preservation at 1580 °C ± 10 °C for 5 minutes, and do not cover the furnace lid during the heat preservation process; The fifth slag removal is: after the fifth heat preservation is completed, remove the high-temperature inclusion slag of crystalline silicon completely, so that the Al content in the molten steel is below 0.003 wt%.

12. The method for melting and casting the nanocrystalline master alloy according to claim 5, characterized in that, In the step (6), The temperature reduction is as follows: adjust the power to 0, perform soft argon blowing with an argon flow rate of 3 - 10 L / min, adjust the power to 260 kW, carry out six heat preservations at 1250 °C ± 10 °C for 30 min each, and cover the furnace lid during the heat preservation process; The six slag skimmings are as follows: after the six heat preservations are completed, skim off the low-temperature inclusion slag of the master alloy to make the Al content in the molten steel below 0.002 wt%, and wait for tapping.

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