Gravity belt throwing device and gravity belt throwing method for producing amorphous thin strips

Abstract

This invention provides a gravity-driven ribbon casting device and method for producing amorphous ribbons, belonging to the field of amorphous ribbon production technology. It includes: two high-frequency induction furnaces, an intermediate insulation pot, and a cooling roller. The two high-frequency induction furnaces are simultaneously supported on a bracket. Each of the two furnaces has a liquid guide pipe at its bottom, with a melting control valve installed on the guide pipe. The intermediate insulation pot is supported on the bracket and located below the high-frequency induction furnaces. An inlet pipe is installed on the intermediate insulation pot, and all guide pipes are connected to the inlet pipe. A drain pipe is installed at the bottom of the intermediate insulation pot, with a ribbon casting control valve installed on the drain pipe. Visible graduation lines are provided on the outer wall of the intermediate insulation pot. The cooling roller is located directly below the intermediate insulation pot, and there is a ribbon casting space between it and the lower end of the drain pipe. This invention utilizes the gravity of the molten alloy to cast the ribbon, while simultaneously using two alternating high-frequency induction furnaces. The molten alloy maintains a certain gravity during casting, resulting in amorphous ribbons of uniform thickness.

Description

Technical Field

[0001] The invention belongs to the technical field of amorphous ribbon production, and in particular relates to a gravity ribbon throwing device for producing amorphous thin ribbons and a gravity ribbon throwing method using the device. Background Art

[0002] Amorphous ribbon is a kind of amorphous structured ribbon made by heating metal raw materials and cooling them. Amorphous metal ribbon has excellent mechanical properties, magnetic properties and chemical stability, and is widely used in electronics, machinery, automobiles, aerospace and other fields. Usually, amorphous ribbon is prepared by the rapid cooling ribbon spinning method.

[0003] In the existing gravity strip throwing device, the melt cannot remain relatively stable due to the pressure above it, and the thickness of the obtained amorphous thin strip is inconsistent. An important indicator of the quality of amorphous thin strip is the uniformity of its thickness. Therefore, in the production process, the change of pressure above the melt has seriously hindered the further improvement of the quality of amorphous alloy strips. Summary of the invention

[0004] The embodiment of the present invention provides a gravity belt throwing device and a gravity belt throwing method for producing an amorphous thin strip, which solves the problem of inconsistent thickness of the amorphous thin strip by stabilizing the pressure of the alloy melt.

[0005] In the first aspect, in order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a gravity belt-swinging device for producing amorphous thin strips, comprising: two high-frequency induction furnaces, an intermediate insulation bag and a cooling roller, the two high-frequency induction furnaces are supported on the bracket at the same time; the bottoms of the two high-frequency induction furnaces are provided with liquid guide tubes, and the liquid guide tubes are provided with a smelting control valve; the intermediate insulation bag is supported on the bracket and is located below the high-frequency induction furnace; the liquid guide tube is connected to the intermediate insulation bag; the bottom of the intermediate insulation bag is provided with a drainage pipe, and the drainage pipe is provided with a belt-swinging control valve; the outer wall of the intermediate insulation bag is provided with visible scale lines; the cooling roller is arranged directly below the intermediate insulation bag, and has a belt-swinging space with the lower end of the drainage pipe.

[0006] In combination with the first aspect, in one feasible manner, a furnace body conical guide groove is provided at the bottom of the high-frequency induction furnace, a bag body conical guide groove is provided at the bottom of the intermediate insulation bag, the liquid guide pipe is provided at the bottom of the furnace body conical guide groove, and the drainage pipe is provided at the bottom of the bag body conical guide groove.

[0007] In combination with the first aspect, in an achievable manner, it further includes a feeding cylinder and a receiving box arranged in the material throwing direction of the cooling roller, the feeding cylinder is tiltedly arranged between the cooling roller and the receiving box, and the inclination angle of the feeding cylinder is 5°-8°.

[0008] In combination with the first aspect, in one achievable manner, the distance of the belt-swinging space between the drainage tube and the cooling roller is 0.1-3 mm.

[0009] In combination with the first aspect, in one feasible manner, a furnace body buckle plate is provided on the upper portion of the bracket, a package body buckle plate is provided in the middle portion of the bracket, a furnace body fixing convex ring supported on the furnace body buckle plate is provided on the outer periphery of the high-frequency induction furnace; and a package body fixing convex ring supported on the package body buckle plate is provided on the outer periphery of the intermediate insulation package.

[0010] In combination with the first aspect, in one achievable manner, the angle between the outlet plane of the lower end of the guide tube and the tangent line of the highest point of the cooling roller is 0°-5°.

[0011] In a second aspect, an embodiment of the present invention further provides a gravity belt spinning method, which uses a gravity belt spinning device for producing amorphous thin strips to prepare an amorphous thin strip, and the method comprises the following steps:

[0012] Step 1: The master alloy in the high-frequency induction furnace is melted in an inert protective gas environment to obtain a homogeneous alloy melt;

[0013] Step 2: Open the smelting control valve at the bottom of the first high-frequency induction furnace, and keep the smelting control valve at the bottom of the second high-frequency induction furnace in a closed state; inject the alloy melt in the first high-frequency induction furnace into the intermediate insulation bag through the liquid guide pipe, and heat and keep it warm to a preset insulation temperature;

[0014] Step 3, turning on the cooling roller to a preset speed, opening the belt-swinging control valve at the bottom of the intermediate insulation bag, and allowing the alloy melt to fall through the drainage pipe and start belt-swinging;

[0015] Step 4. When the alloy melt level in the middle insulation bag drops to the preset minimum belt-spinning level, open the second high-frequency induction furnace and close the first high-frequency induction furnace. The two high-frequency induction furnaces are used alternately to keep the preset minimum belt-spinning level in the middle insulation bag unchanged, and continuously complete the belt-spinning of the alloy melt under its own weight.

[0016] In combination with the second aspect, in one achievable manner, in step two, the preset insulation temperature of the intermediate insulation bag is 1350-1450°C.

[0017] In combination with the second aspect, in one achievable manner, in step three, a transverse airflow is applied to the belt-swinging space between the drainage tube and the cooling roller, and the intensity of the transverse airflow is 2-10 ml / min.

[0018] In conjunction with the second aspect, in one achievable manner, a method for setting the visible scale lines on the outer wall of the intermediate insulation bag includes:

[0019] According to the liquid pressure of the alloy melt in the intermediate insulation bag, visible scale lines are set on the outer wall of the intermediate insulation bag from the preset lowest belt-spinning liquid level upward at F, F+10, F+20, F+30, F+40, F+50, F+60, F+70, and F+80, respectively, and the unit is kPa.

[0020] Compared with the prior art, the gravity belt-spinning device and gravity belt-spinning method for producing amorphous thin strips provided by the present invention have the following beneficial effects: there is no need to introduce pressurized gas into the intermediate insulation bag, but the alloy melt is spun by its own gravity, and at the same time, the preset minimum belt-spinning liquid level of the alloy melt in the intermediate insulation bag needs to be maintained by two alternating high-frequency induction furnaces, so that the alloy melt maintains a certain gravity at the preset minimum belt-spinning liquid level, thereby obtaining an amorphous thin strip with uniform thickness. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic structural diagram of a gravity strip-throwing device for producing amorphous thin strips provided in an embodiment of the present invention;

[0022] Description of reference numerals:

[0023] 1. High-frequency induction furnace; 2. Furnace body fixing convex ring; 3. Furnace body buckle plate; 4. Liquid guide tube; 5. Melting control valve; 6. Package body fixing convex ring; 7. Package body buckle plate; 8. Intermediate insulation package; 9. Induction coil; 10. Belt throwing control valve; 11. Drainage pipe; 12. Cooling roller; 13. Material receiving box; 14. Feeding cylinder; 15. Amorphous thin strip; 16. Belt throwing space; 17. Visual scale line; 18. Bracket. DETAILED DESCRIPTION

[0024] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] See also Figure 1Now, the gravity belt-swinging device for producing amorphous thin strips provided by the present invention is described. The gravity belt-swinging device for producing amorphous thin strips comprises: two high-frequency induction furnaces 1, an intermediate insulation bag 8 and a cooling roller 12, the two high-frequency induction furnaces 1 are supported on a bracket 18 at the same time; the bottoms of the two high-frequency induction furnaces 1 are provided with a liquid guide tube 4, and a smelting control valve 5 is provided on the liquid guide tube 4; the intermediate insulation bag 8 is supported on the bracket 18 and is located below the high-frequency induction furnace 1; the liquid guide tube 4 is connected to the intermediate insulation bag 8; the bottom of the intermediate insulation bag 8 is provided with a drainage pipe 11, and a belt-swinging control valve 10 is provided on the drainage pipe 11; the outer wall of the intermediate insulation bag 8 is provided with a visible scale line 17; the cooling roller 12 is provided directly below the intermediate insulation bag 8, and has a belt-swinging space 16 with the lower end of the drainage pipe 11.

[0026] Compared with the prior art, the gravity belt-swinging device and gravity belt-swinging method for producing an amorphous thin strip 15 provided by the present invention have the following beneficial effects: there is no need to introduce pressurized gas into the intermediate insulation bag 8, but the alloy melt is spun by its own gravity. At the same time, the preset minimum belt-swinging liquid level of the alloy melt in the intermediate insulation bag 8 needs to be maintained by two alternating high-frequency induction furnaces 1, so that the alloy melt maintains a certain gravity at the preset minimum belt-swinging liquid level, thereby obtaining an amorphous thin strip 15 with uniform thickness.

[0027] In some embodiments, see Figure 1 As shown, the bottom of the high-frequency induction furnace 1 is provided with a furnace body conical guide groove, the bottom of the intermediate insulation bag 8 is provided with a bag body conical guide groove, the liquid guide pipe 4 is provided at the bottom of the furnace body conical guide groove, and the drainage pipe 11 is provided at the bottom of the bag body conical guide groove. The conical guide grooves are provided at the bottom of the high-frequency induction furnace 1 and the intermediate insulation bag 8, which have the functions of guiding and converging the alloy melt, thereby improving the utilization rate of the alloy melt.

[0028] In some embodiments, see Figure 1 As shown, the device also includes a feeding drum 14 and a receiving box 13 arranged in the direction of the cooling roller 12 to throw the material. The feeding drum 14 is tilted between the cooling roller 12 and the receiving box 13, and the tilt angle of the feeding drum 14 is 5°-8°. The feeding drum 14 is tilted to facilitate the amorphous thin strip 15 to be fed into the receiving box 13. The length of the feeding drum 14 is 1.5-2.5m.

[0029] In some embodiments, see Figure 1 As shown, the distance of the belt-swinging space 16 between the drain pipe 11 and the cooling roller 12 is 0.1-3 mm, which is reserved for the belt-swinging of the alloy melt. For example, the distance is 0.1 mm, 0.2 mm, 0.3 mm, 1 mm, 1.2 mm, 3 mm, etc.

[0030] In some embodiments, see Figure 1As shown, a furnace body buckle plate 3 is provided on the upper part of the bracket 18, a package body buckle plate 7 is provided in the middle part of the bracket 18, a furnace body fixing convex ring 2 supported on the furnace body buckle plate 3 is provided on the outer periphery of the high-frequency induction furnace 1; a package body fixing convex ring 6 supported on the package body buckle plate 7 is provided on the outer periphery of the middle insulation bag 8. Among them, two annular furnace body buckle plates 3 are provided on the bracket 18 to support two high-frequency induction furnaces 1; similarly, the package body buckle plate 7 is also annular in shape to support the package body fixing convex ring 6.

[0031] In some embodiments, see Figure 1 As shown, the angle between the outlet plane of the lower end of the guide tube 11 and the tangent line of the highest point of the cooling roller 12 is 0°-5°. That is, the inclination angle of the outlet plane of the lower end of the guide tube 11 is less than or equal to 5° to ensure that the alloy melt falls perpendicularly to the cooling roller 12.

[0032] The method for setting the visible scale lines 17 on the outer wall of the intermediate insulation bag 8 of the present invention comprises: according to the liquid pressure of the alloy melt in the intermediate insulation bag 8, the visible scale lines 17 are set on the outer wall of the intermediate insulation bag 8 at F, F+10, F+20, F+30, F+40, F+50, F+60, F+70, and F+80 from the preset lowest belt-spinning liquid level upward, and the unit is kPa. The present invention calculates the pressure corresponding to the liquid level using the liquid pressure formula P=ρgh, and divides the visible scale lines 17 according to the calculation results, and the visible scale lines 17 are 10 kPa, 20 kPa, 30 kPa, 40 kPa, 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa, etc. from bottom to top. In order to ensure that the thickness of the amorphous thin strip 15 is uniform, the height of the alloy melt in the intermediate insulation bag 8 is always maintained above 40 kPa of the visible scale line 17 to ensure that the thickness of the amorphous thin strip 15 is uniform.

[0033] In the present invention, 40 kPa is the preset minimum strip-spinning liquid level pressure. When the alloy melt drops to this position, the second high-frequency induction furnace 1 is opened to inject the alloy melt into the intermediate insulation bag 8. In this way, the pressure in the intermediate insulation bag 8 can be always maintained, thereby ensuring the uniformity of the thickness of the amorphous thin strip 15.

[0034] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0035] Based on the same inventive concept, the embodiment of the present application also provides a gravity belt throwing method, and the following embodiments are carried out based on the gravity belt throwing device:

[0036] Example 1

[0037] Step 1: Fe, Si and B with a purity of 99.99% are mixed according to the molecular formula Fe 75Si 15 B 10 The ingredients are batched, and the powder particle size is 5-8μm;

[0038] The prepared raw materials are placed in a clean corundum crucible and smelted in a high-frequency induction furnace. The vacuum degree in the furnace is below 0.001Pa at the initial stage of smelting, and the vacuum degree during the smelting process is lower than 0.1Pa. To ensure uniform composition, the smelting is repeated 6 times to obtain the master alloy.

[0039] Then, the master alloy is melted in an inert protective gas environment of the high-frequency induction furnace 1 to obtain a homogeneous alloy melt.

[0040] Step 2: open the smelting control valve 5 at the bottom of the first high-frequency induction furnace, and the smelting control valve 5 at the bottom of the second high-frequency induction furnace is in a closed state. The alloy melt in the first high-frequency induction furnace is injected into the intermediate insulation bag 8 through the liquid guide pipe 4, and is heated and insulated under the action of the induction coil 9 wrapped around the outside of the intermediate insulation bag 8. The insulation temperature is 1350-1450°C.

[0041] Step three, open the cooling roller 12 and set the speed to 2000r / min. When the molten metal height reaches 40kPa or more of the visible scale line 17, open the belt-swinging control valve 10, and the alloy melt enters the drainage tube 11. In the belt-swinging space 16 between the bottom of the drainage tube 11 and the cooling roller 12, the lateral airflow intensity to which the alloy melt is subjected is 2-10ml / min, and gravity belt-swinging is performed.

[0042] Step four, in order to ensure the uniform thickness of the amorphous thin strip, the height of the molten alloy in the intermediate insulation bag 8 is always maintained above 40 kPa of the visible scale line 17 through the smelting control valve 5 to ensure the uniform thickness of the amorphous thin strip; when the alloy melt level in the intermediate insulation bag 8 drops to the preset minimum strip-spinning liquid level, open the second high-frequency induction furnace and close the first high-frequency induction furnace; the two high-frequency induction furnaces 1 are used alternately to keep the preset minimum strip-spinning liquid level in the intermediate insulation bag 8 unchanged, and continuously complete the strip-spinning of the alloy melt under its own weight.

[0043] Step 5: The amorphous ribbon 15 obtained by gravity spinning passes through the feeding cylinder 14 and enters the receiving box 13, and the thickness of the amorphous ribbon is uniform and stable at about 25 μm.

[0044] Example 2

[0045] Step 1: Fe, Si, B, P, C, and Cu with a purity of 99.99% are mixed according to the molecular formula Fe 84.59 Si 0.56 B 9.35 P 3.5 C 1.2 Cu 0.8 The ingredients are batched, and the powder particle size is 5-8μm;

[0046] The prepared raw materials are placed in a clean corundum crucible and smelted in a high-frequency induction furnace. The vacuum degree in the furnace is below 0.001Pa at the initial stage of smelting, and the vacuum degree during the smelting process is lower than 0.1Pa. Cu is volatile, and an inner convex cover is added to the crucible during smelting. In order to ensure uniform composition, the smelting is repeated 6 times to obtain the master alloy.

[0047] Then, the master alloy is melted in an inert protective gas environment of the high-frequency induction furnace 1 to obtain a homogeneous alloy melt.

[0048] Step 2, open the smelting control valve 5 at the bottom of the first high-frequency induction furnace, and the smelting control valve 5 at the bottom of the second high-frequency induction furnace is in a closed state. The alloy melt in the first high-frequency induction furnace is injected into the intermediate insulation bag through the liquid guide pipe 4, and is heated and kept warm under the action of the induction coil 9 wrapped around the outside of the intermediate insulation bag 8. Since Cu is easy to volatilize at high temperature, the insulation temperature is 1050-1150°C.

[0049] Step three, open the cooling roller 12 and set the rotation speed to 1200r / min. When the molten metal height reaches 40kPa or more of the visible scale line 17, open the belt-swinging control valve 10, and the alloy melt enters the drainage tube 11. In the belt-swinging space 16 between the bottom of the drainage tube 11 and the cooling roller 12, the lateral airflow intensity to which the alloy melt is subjected is 2-10ml / min, and gravity belt-swinging is performed.

[0050] Step four, in order to ensure the uniform thickness of the amorphous thin strip, the height of the molten alloy in the intermediate insulation bag 8 is always maintained above 40kPa on the visible scale line through the smelting control valve 5 to ensure the uniform thickness of the amorphous thin strip; when the alloy melt level in the intermediate insulation bag 8 drops to the preset minimum strip-spinning liquid level, open the second high-frequency induction furnace and close the first high-frequency induction furnace; the two high-frequency induction furnaces 1 are used alternately to keep the preset minimum strip-spinning liquid level in the intermediate insulation bag 8 unchanged, and continuously complete the strip-spinning of the alloy melt under its own weight.

[0051] Step 5: The amorphous ribbon 15 obtained by gravity spinning passes through the feeding cylinder 14 and enters the receiving box 13, and the thickness of the amorphous ribbon is uniform and stable at about 23 μm.

[0052] Example 3

[0053] Step 1: Fe, Si, B, P, and C with a purity of 99.99% are mixed according to the molecular formula Fe 83 SiC 11 P3C1 is used for batching, and the powder particle size is 5-8μm;

[0054] The prepared raw materials are placed in a clean corundum crucible and smelted in a high-frequency induction furnace. The vacuum degree in the furnace is below 0.001Pa at the initial stage of smelting, and the vacuum degree during the smelting process is lower than 0.1Pa. Cu is volatile, and an inner convex cover is added to the crucible during smelting. In order to ensure uniform composition, the smelting is repeated 6 times to obtain the master alloy.

[0055] Then, the master alloy is melted in an inert protective gas environment of the high-frequency induction furnace 1 to obtain a homogeneous alloy melt.

[0056] Step 2: open the smelting control valve 5 at the bottom of the first high-frequency induction furnace, and the smelting control valve 5 at the bottom of the second high-frequency induction furnace is in a closed state. The alloy melt in the first high-frequency induction furnace is injected into the intermediate insulation bag 8 through the liquid guide pipe 4, and is heated and insulated under the action of the induction coil 9 wrapped around the outside of the intermediate insulation bag 8. The insulation temperature is 1350-1450°C.

[0057] Step three, open the cooling roller 12 and set the rotation speed to 1900r / min. When the molten metal height reaches 40kPa or more of the visible scale line 17, open the belt-swinging control valve 10, and the alloy melt enters the drainage tube 11. In the belt-swinging space 16 between the bottom of the drainage tube 11 and the cooling roller 12, the lateral airflow intensity to which the alloy melt is subjected is 2-10ml / min, and gravity belt-swinging is performed.

[0058] Step four, in order to ensure the uniform thickness of the amorphous thin strip, the height of the molten alloy in the intermediate insulation bag 8 is always maintained above 40kPa on the visible scale line through the smelting control valve 5 to ensure the uniform thickness of the amorphous thin strip; when the alloy melt level in the intermediate insulation bag 8 drops to the preset minimum strip-spinning liquid level, open the second high-frequency induction furnace and close the first high-frequency induction furnace; the two high-frequency induction furnaces 1 are used alternately to keep the preset minimum strip-spinning liquid level in the intermediate insulation bag 8 unchanged, and continuously complete the strip-spinning of the alloy melt under its own weight.

[0059] Step 5: The amorphous ribbon 15 obtained by gravity spinning passes through the feeding cylinder 14 and enters the receiving box 13, and the thickness of the amorphous ribbon is uniform and stable at about 22 μm.

[0060] Example 4

[0061] Step 1: Fe, Si, B, P, C, and Cu with a purity of 99.99% are mixed according to the molecular formula Fe 85.4 Si3B 5.2 P 3.8 C 1.6 Cu1 is used for batching, and the powder particle size is 5-8μm;

[0062] The prepared raw materials were placed in a clean corundum crucible and smelted in a high-frequency induction furnace. The vacuum degree in the furnace was below 0.001 Pa at the initial stage of smelting, and the vacuum degree during the smelting process was lower than 0.1 Pa. As in Example 2, an inner convex cover was added to the crucible during smelting to prevent Cu from volatilizing. To ensure uniform composition, the smelting was repeated 6 times to obtain a master alloy.

[0063] Then, the master alloy is melted in an inert protective gas environment of the high-frequency induction furnace 1 to obtain a homogeneous alloy melt.

[0064] Step 2, open the smelting control valve 5 at the bottom of the first high-frequency induction furnace, and the smelting control valve 5 at the bottom of the second high-frequency induction furnace is in a closed state. The alloy melt in the first high-frequency induction furnace is injected into the intermediate insulation bag 8 through the liquid guide pipe 4, and is heated and kept warm under the action of the induction coil 9 wrapped around the outside of the intermediate insulation bag 8. The same as Example 2, to prevent Cu from volatilizing at high temperature, the insulation temperature is 1050-1150°C.

[0065] Step three, open the cooling roller 12 and set the speed to 2000r / min. When the molten metal height reaches 40kPa or more of the visible scale line 17, open the belt-swinging control valve 10, and the alloy melt enters the drainage tube 11. In the belt-swinging space 16 between the bottom of the drainage tube 11 and the cooling roller 12, the lateral airflow intensity to which the alloy melt is subjected is 2-10ml / min, and gravity belt-swinging is performed.

[0066] Step four, in order to ensure the uniform thickness of the amorphous thin strip, the height of the molten alloy in the intermediate insulation bag 8 is always maintained above 40 kPa of the visible scale line 17 through the smelting control valve 5 to ensure the uniform thickness of the amorphous thin strip; when the alloy melt level in the intermediate insulation bag 8 drops to the preset minimum strip-spinning liquid level, open the second high-frequency induction furnace and close the first high-frequency induction furnace; the two high-frequency induction furnaces 1 are used alternately to keep the preset minimum strip-spinning liquid level in the intermediate insulation bag 8 unchanged, and continuously complete the strip-spinning of the alloy melt under its own weight.

[0067] Step 5: The amorphous ribbon 15 obtained by gravity spinning passes through the feeding cylinder 14 and enters the receiving box 13, and the thickness of the amorphous ribbon is uniform and stable at about 20 μm.

[0068] Table 1 shows the thickness comparison between the amorphous thin ribbon obtained by the embodiment of the present invention and the amorphous thin ribbon obtained by the existing gravity belt throwing device.

[0069] Table 1 Thickness values ​​of amorphous thin strips obtained by the present invention and amorphous thin strips obtained by existing devices

[0070]

[0071] It can be seen from the data comparison in Table 1 that the thickness of the amorphous thin ribbon prepared by the present invention is uniform.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A gravity belt spinning method, using a gravity belt spinning device for producing amorphous thin strips to prepare amorphous thin strips, characterized in that: The method comprises the following steps: Step 1, the master alloys in two high-frequency induction furnaces (1) are melted in an inert protective gas environment to obtain a homogeneous alloy melt; Step 2: opening the smelting control valve (5) at the bottom of the first high-frequency induction furnace, keeping the smelting control valve (5) at the bottom of the second high-frequency induction furnace in a closed state, injecting the alloy melt in the first high-frequency induction furnace into the intermediate insulation bag (8) through the liquid guide pipe (4), and heating and heat preservation to a preset insulation temperature; Step 3, turning on the cooling roller (12) to a preset speed, opening the belt-swinging control valve at the bottom of the intermediate insulation bag (8), and allowing the alloy melt to fall through the drainage pipe (11) and start belt-swinging; Step 4, when the alloy melt liquid level in the middle insulation bag (8) drops to a preset minimum belt-spinning liquid level, the second high-frequency induction furnace is turned on and the first high-frequency induction furnace is turned off; the two high-frequency induction furnaces are used alternately to keep the preset minimum belt-spinning liquid level in the middle insulation bag (8) unchanged, and continuously complete the belt-spinning of the alloy melt under its own weight; In step 1, Fe, Si, B, P, C, and Cu with a purity of 99.99% are mixed according to the molecular formula Fe 75 Si 15 B 10 , Fe 84.59 Si 0.56 B 9.35 P 3.5 C 1.2 Cu 0.8 , Fe 83 SiC 11 P3C1 or Fe 85.4 Si3B 5.2 P 3.8 C 1.6 Any one of Cu1 is used for batching, and the powder particle size is 5-8μm; The prepared raw materials are placed in a clean corundum crucible and smelted in a high-frequency induction furnace. The vacuum degree in the furnace is below 0.001Pa at the initial stage of smelting, and the vacuum degree during the smelting process is lower than 0.1Pa. To ensure uniform composition, the smelting is repeated 6 times to obtain the master alloy. In step 2, the preset insulation temperature of the intermediate insulation bag (8) is 1350-1450° C.; The gravity strip-throwing device for producing amorphous thin strips comprises: Two high-frequency induction furnaces (1) are supported on a bracket (18) at the same time; a liquid guide pipe (4) is provided at the bottom of each of the two high-frequency induction furnaces (1), and a smelting control valve (5) is provided on the liquid guide pipe (4); An intermediate heat-insulating bag (8) is supported on the support (18) and is located below the high-frequency induction furnace (1); the liquid guide pipe (4) is connected to the intermediate heat-insulating bag (8); a drainage pipe (11) is provided at the bottom of the intermediate heat-insulating bag (8), and a belt-swinging control valve (10) is provided on the drainage pipe (11); and a visible scale line (17) is provided on the outer wall of the intermediate heat-insulating bag (8); and A cooling roller (12) is arranged directly below the intermediate heat-insulating bag (8) and has a belt-swinging space (16) with the lower end of the drainage pipe (11); The visible scale lines (17) on the outer wall of the intermediate insulation bag (8) include: According to the liquid pressure of the alloy melt in the intermediate insulation bag (8), visible scale lines (17) are set on the outer wall of the intermediate insulation bag (8) at F, F+10, F+20, F+30, F+40, F+50, F+60, F+70, and F+80 from the preset lowest belt-spinning liquid level upward, and the unit is kPa.

2. The gravity belt throwing method according to claim 1, characterized in that: The bottom of the high-frequency induction furnace (1) is provided with a furnace body conical guide groove, the bottom of the intermediate heat-insulating bag (8) is provided with a bag body conical guide groove, the liquid guide pipe (4) is provided at the bottom of the furnace body conical guide groove, and the drainage pipe (11) is provided at the bottom of the bag body conical guide groove.

3. The gravity belt throwing method according to claim 1, characterized in that: It also includes a feeding cylinder (14) and a material receiving box (13) which are arranged in the material throwing direction of the cooling roller (12); the feeding cylinder (14) is inclined between the cooling roller (12) and the material receiving box (13); and the inclination angle of the feeding cylinder (14) is 5°-8°.

4. The gravity belt throwing method according to claim 1, characterized in that: The distance of the belt-swinging space (16) between the drainage tube (11) and the cooling roller (12) is 0.1-3 mm.

5. The gravity belt throwing method according to claim 1, characterized in that: A furnace body buckle plate (3) is arranged on the upper part of the bracket (18), a package body buckle plate (7) is arranged on the middle part of the bracket (18), a furnace body fixing convex ring (2) supported on the furnace body buckle plate (3) is arranged on the outer periphery of the high-frequency induction furnace (1); and a package body fixing convex ring (6) supported on the package body buckle plate (7) is arranged on the outer periphery of the intermediate heat-insulating package (8).

6. The gravity belt throwing method according to claim 1, characterized in that: The angle between the outlet plane at the lower end of the drainage tube (11) and the tangent line at the highest point of the cooling roller (12) is 0°-5°.

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