A continuous preparation method for thick-gauge amorphous alloy strip

Abstract

The present invention belongs to the field of amorphous alloy preparation, and specifically relates to a method for continuously preparing thick-gauge amorphous alloy strips. The method forms a metal shell solidified on one side by spraying the alloy on the surface of a casting roller, and then extrude the two metal shells through two casting rollers to form a complete metal strip, which is suitable for preparing zirconium-based, copper-based, magnesium-based and other amorphous alloy strips with certain glass-forming ability. The main process is: ① placing the heated and molten amorphous master alloy melt in a crucible. ② Then the alloy melt is evenly sprayed on the surfaces of the casting rollers on both sides through the distribution port, and the alloy melt is cooled by heat conduction through the water-cooled casting roller and solidified on one side. ③ The alloy cooled on one side is extruded into an alloy strip by the rolling force of the casting roller. In the amorphous formation process of the present invention, there is no wedge-shaped molten pool, and the alloy cooling rate is fast, the deformation is small, and the process is stable. The method of the present invention can be used to efficiently and continuously prepare thick-gauge amorphous strips.

Description

Technical Field

[0001] The invention belongs to the field of amorphous alloy preparation, and in particular relates to a method for continuously preparing thick-gauge amorphous alloy strips. Background Art

[0002] Amorphous alloys, also known as metallic glass, are mainly composed of metal elements and metal bonds, but do not have the ordered internal structure of crystalline materials. This makes it have the characteristics of both metal and glass, with excellent mechanical properties, physical properties and chemical properties, making it have broad application prospects in many fields such as aerospace, weapons industry, precision instruments, electronic telecommunications, biomedicine and power transmission.

[0003] At present, the commercial production methods of amorphous alloy products are mainly single-roll strip spinning method and copper mold casting method. The single-roll strip spinning method can produce amorphous thin strips with a thickness of tens of microns. The Fe-based amorphous alloys prepared by this method have been widely used in transformer core materials. The copper mold die casting method is the main preparation method for bulk amorphous alloy products, and has been initially applied in the fields of sporting goods and electronic products. However, the traditional copper mold casting process for preparing bulk amorphous alloy products has problems such as low production efficiency, long production cycle, unstable product quality, and high loss rate. And due to its harsh forming conditions, only small-sized amorphous alloy products can be produced, which greatly limits the promotion and application of amorphous alloy products. In addition, although plate and strip products are important basic structural materials, there is no effective preparation method for thick-gauge amorphous alloy plates and strips.

[0004] The twin-roll thin strip casting process is a technology that uses liquid metal to directly produce metal strips. Compared with conventional casting processes, it has the characteristics of short process, fast cooling rate, and near-final forming, which meets the forming conditions of amorphous alloys. In addition, the use of twin-roll thin strip casting technology to prepare amorphous alloys has many advantages. First, compared with the single-roll strip throwing method, the twin-roll casting process has the characteristics of double-sided cooling and rolling forming, which can increase the alloy cooling rate, improve the alloy surface quality, and prepare thicker amorphous alloy strips. Second, the short process and continuous forming casting and rolling process characteristics can improve the preparation efficiency of amorphous alloys, reduce production costs, and reduce energy consumption, which is in line with the development concept of "green manufacturing". Third, the characteristics of rolling forming can inhibit the generation of casting defects such as pores and insufficient filling in the alloy, thereby improving the yield rate of the alloy. Therefore, the development of the twin-roll thin strip casting process for amorphous alloy strips can fill the gap in amorphous alloy strip products, which is of great significance to promoting the industrial production and wide application of amorphous alloy products.

[0005] Over the past many years, researchers such as Lee's group at Pohang University in South Korea, Akihisa Inoue's group at Tohoku University in Japan, and Zhang Long, a researcher at the Institute of Metal Research, Chinese Academy of Sciences, have successively conducted preliminary explorations on the casting and rolling of amorphous alloys by thin strips, and have proved its theoretical feasibility. However, whether it is possible to achieve stable continuous casting and rolling of high-quality, large-area, amorphous alloy plates and strips has not yet been proven. The properties and formation conditions of amorphous alloys are different from those of conventional crystalline metals, and their formation process requires a continuous high cooling rate. However, during conventional twin-roller thin strip casting and rolling, the alloy in the molten pool will inevitably reflux due to the rolling deformation process, which will cause turbulent vortices in the alloy in the molten pool, causing some alloys to stay in the molten pool for too long, resulting in alloy crystallization. Therefore, conventional twin-roller thin strip casting and rolling technology is not fully applicable to the continuous preparation of amorphous alloy plates and strips. Summary of the invention

[0006] The purpose of the present invention is to provide a method for continuous preparation of thick-gauge amorphous alloy plates and strips. According to the characteristics of bulk amorphous solidification, combined with twin-roll casting and rolling technology, a new flow distribution method is adopted. The flow distribution nozzle penetrates deep into the molten pool to suppress alloy turbulence, change the shape of the alloy cooling area, and suppress the formation of wedge-shaped molten pool, so that the casting and rolling process of the amorphous alloy has a high cooling rate and high stability.

[0007] In order to solve the above technical problems, the technical solution of the present invention is:

[0008] A method for continuously preparing thick-gauge amorphous alloy strips, wherein the alloy is sprayed onto the surface of a water-cooled casting roller to form a single-sided solidified metal shell, and then two metal shells are squeezed through two water-cooled casting rollers to form a complete amorphous alloy strip.

[0009] The continuous preparation method of thick-gauge amorphous alloy strip is carried out according to the following steps:

[0010] (1) transferring the heated and molten amorphous master alloy melt into a crucible and stabilizing its temperature so that it has a superheat of 100 to 300° C.;

[0011] (2) The amorphous master alloy melt is uniformly sprayed onto the surfaces of the water-cooled casting rollers on both sides through the flow distribution ports, and the amorphous master alloy melt is cooled by heat conduction through the water-cooled casting rollers and solidified on one side;

[0012] (3) The amorphous alloy cooled on one side is extruded into an amorphous alloy strip by the rolling force of the water-cooled casting roll.

[0013] In the method for continuously preparing thick-gauge amorphous alloy strips, the crucible and the flow distribution nozzle are preheated, and the preheating method includes but is not limited to resistance wire heating or induction heating.

[0014] In the continuous preparation method of thick-gauge amorphous alloy strips, the amorphous master alloy melt is distributed through a distribution nozzle, cooled and rolled into shape by two water-cooled casting rollers, but there is no wedge-shaped molten pool during the forming process.

[0015] The continuous preparation method of thick-gauge amorphous alloy strips, the device used in the method includes: a thermocouple, a crucible, an alloy melt, a flow distribution nozzle, and a water-cooled casting roller, and the specific structure is as follows:

[0016] The alloy raw materials are placed in a crucible and smelted to form an alloy melt. The crucible is equipped with a thermocouple for temperature measurement. A distribution nozzle is tightly arranged at the bottom of the crucible and is connected to the distribution nozzle through an outlet. The lower end of the distribution nozzle is placed in the roller gap between two horizontally opposed and counter-rotating water-cooled casting rollers and is in close contact with the water-cooled casting rollers. In the preparation process of the amorphous alloy, the alloy melt flows out through the nozzle of the distribution nozzle and is cooled in contact with the water-cooled casting roller, and is rolled into an alloy plate and strip by the water-cooled casting roller.

[0017] The continuous preparation method of thick-gauge amorphous alloy plates and strips is described, and the main body of the distribution nozzle of the distribution nozzle is composed of a vertically arranged rectangular plate section, a horizontal straight quadrangular prism wedge section and a horizontal straight triangular prism pointed corner section, which are integrated from top to bottom. The longitudinal section of the rectangular plate section is a hollow flat rectangle, the longitudinal section of the straight quadrangular prism wedge section is a hollow inverted isosceles trapezoid, and the longitudinal section of the straight triangular prism pointed corner section is an inverted isosceles triangle. The hollow parts of the rectangular plate section and the straight quadrangular prism wedge section are combined from top to bottom to form the distribution nozzle cavity. A narrow slit-shaped distribution nozzle outlet is opened on the upper horizontal plane of the straight triangular prism pointed corner section. The upper end of the distribution nozzle cavity is connected to the bottom outlet of the crucible, and the lower end of the distribution nozzle cavity is connected to the distribution nozzle outlet. The outer periphery of the rectangular plate section and the straight quadrangular prism wedge section is conformally coated with an insulation layer.

[0018] In the continuous preparation method of thick-gauge amorphous alloy plates and strips, the longitudinal section of the straight triangular prism tip section of the flow distribution nozzle is a sharp triangle, the amorphous master alloy melt flows out from both sides of the flow distribution nozzle and directly contacts the water-cooled casting roller, and the tip of the flow distribution nozzle penetrates into the roller gap to occupy the central area of ​​the amorphous master alloy molten pool, so that the flow of the amorphous master alloy is close to laminar flow.

[0019] In the continuous preparation method of thick-gauge amorphous alloy strips, the gap between water-cooled casting rolls is 0.2-5 mm, and a certain casting and rolling force of 10-30 kN is applied.

[0020] In the method for continuously preparing thick-gauge amorphous alloy strips, the material of the flow nozzle is zirconium oxide, boron nitride or high-purity graphite which has a certain strength and does not react with the alloy melt.

[0021] The design concept of the present invention is:

[0022] The present invention fixes the contact distance between the alloy melt and the casting rollers through the design of the distribution nozzle to distribute the flow deeply, thereby improving the uniformity of the alloy cooling process. The flow of the alloy melt is restricted by the tip of the distribution nozzle, making its flow closer to laminar flow, inhibiting the generation of turbulent vortices in the alloy melt between the casting rollers, and avoiding crystallization during the alloy cooling process due to the fact that part of the alloy stays in the cooling area for too long and the cooling rate is too slow.

[0023] The advantages and beneficial effects of the present invention are:

[0024] 1. The present invention is different from conventional twin-roller thin strip casting and rolling technology. No wedge-shaped molten pool is generated during the cooling and forming process of the amorphous alloy, which can suppress the turbulent vortex generated during the cooling process, increase the cooling rate of the alloy, and is suitable for the continuous preparation of amorphous alloy plates and strips.

[0025] 2. The present invention does not have a free liquid surface, and the cooling and solidification process of the alloy is stable and continuous, which can effectively increase the stability of the cooling forming process of the amorphous alloy and improve the quality of the amorphous alloy strip.

[0026] 3. The longitudinal section of the sharp corner section of the straight triangular prism of the distribution nozzle of the present invention is a sharp triangle. The amorphous mother alloy melt flows out from both sides of the distribution nozzle and directly contacts the water-cooled casting roller. The tip of the distribution nozzle penetrates into the roller gap to occupy the central area of ​​the amorphous mother alloy molten pool, so that the flow of the amorphous mother alloy is close to laminar flow. This method can effectively suppress the vortex generated by the turbulence of the alloy melt in the molten pool and reduce the time that the alloy stays in the molten pool.

[0027] 4. The method of the present invention is suitable for preparing zirconium-based, copper-based, magnesium-based and other amorphous alloy plates and strips with certain glass-forming ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of a device for continuously preparing thick-gauge amorphous alloy plates and strips according to the present invention, and the right figure is a partial enlarged view of the left figure.

[0029] In the figure: 1 thermocouple, 2 crucible, 3 alloy melt, 4 flow nozzle, 5 water-cooled casting roller, 6 alloy plate and strip.

[0030] Figure 2-Figure 3 It is a schematic diagram of the structure of the flow nozzle. Figure 2 The main cross-sectional view, Figure 3 for Figure 2 Side view of the cloth flow nozzle body 8 in.

[0031] In the figure: 7 is the inner cavity of the flow nozzle, 8 is the main body of the flow nozzle (81 is a rectangular plate-shaped section, 82 is a straight quadrangular prism wedge-shaped section, 83 is a straight triangular prism pointed corner section), 9 is a heat-insulating layer, and 10 is a nozzle of the flow nozzle.

[0032] Figure 4 This is a macroscopic photograph of the 0.6 mm thick amorphous alloy strip obtained in the experiment.

[0033] Figure 5 This is a microstructure photo of a 0.6 mm thick amorphous alloy strip obtained in the experiment. The inset is the XRD curve, the horizontal axis 2θ is the diffraction angle (degree), and the vertical axis intensity represents the relative intensity (au). DETAILED DESCRIPTION

[0034] like Figure 1-Figure 3 As shown, the present invention is a device for continuously preparing thick-gauge amorphous alloy strips, which mainly includes: a thermocouple 1, a crucible 2, an alloy melt 3, a flow distribution nozzle 4, a water-cooled casting roller 5, an alloy strip 6, etc. The specific structure is as follows:

[0035] The alloy raw material is placed in a crucible 2 and smelted to form an alloy melt 3. The crucible 2 is equipped with a thermocouple 1 for temperature measurement. A distribution nozzle 4 is closely arranged at the bottom of the crucible 2 and is connected to the distribution nozzle 4 through an outlet. The lower end of the distribution nozzle 4 is placed in the roller gap between two horizontally opposed and counter-rotating water-cooled casting rollers 5 and is in close contact with the water-cooled casting rollers 5. In the process of preparing the amorphous alloy, the alloy melt 3 flows out through the distribution nozzle nozzle 10 and contacts with the water-cooled casting roller 5 for cooling, and is rolled into an alloy strip 6 through the water-cooled casting roller 5.

[0036] like Figure 2-Figure 3 As shown, the distribution nozzle body 8 of the distribution nozzle 4 is composed of a vertically arranged rectangular plate section 81, a horizontal straight quadrangular prism wedge section 82 and a horizontal straight triangular prism pointed corner section 83 which are integrated from top to bottom. The longitudinal section of the rectangular plate section 81 is a hollow flat rectangle, the longitudinal section of the straight quadrangular prism wedge section 82 is a hollow inverted isosceles trapezoid, and the longitudinal section of the straight triangular prism pointed corner section 83 is an inverted isosceles triangle. The hollow parts of the rectangular plate section 81 and the straight quadrangular prism wedge section 82 are combined from top to bottom to form a distribution nozzle cavity 7. A narrow slit-shaped distribution nozzle outlet 10 is opened on the upper end horizontal plane of the straight triangular prism pointed corner section 83. The upper end of the distribution nozzle cavity 7 is connected to the bottom outlet of the crucible 2, and the lower end of the distribution nozzle cavity 7 is connected to the distribution nozzle outlet 10. The outer periphery of the rectangular plate section 81 and the straight quadrangular prism wedge section 82 is conformally coated with an insulation layer 9.

[0037] In the specific implementation process, the present invention is applicable to the preparation of zirconium-based, magnesium-based, copper-based and other amorphous alloy strips, with Zr in the zirconium-based amorphous alloy 55 Cu 30 Al 10 Take Ni5 amorphous alloy as an example. Its preparation method is: stabilize the heated and melted amorphous master alloy melt at a process temperature of about 100-300°C, and then pour it into the preheated crucible 2. The alloy melt flows out through the distribution nozzle 10 and contacts with the water-cooled casting roller 5 for cooling, and is finally cast and rolled by the water-cooled casting roller 5.

[0038] The present invention is further described in detail below through examples and drawings.

[0039] Example:

[0040] In this embodiment, the continuous preparation method of thick-gauge amorphous alloy strip is as follows:

[0041] a. Heat the alloy raw materials until they are completely melted, and continue smelting at 1150°C for 10 minutes to form a master alloy melt.

[0042] b. Install the crucible and the distribution nozzle preheated to 1150℃ to the working position, and pour the master alloy melt into the preheated crucible.

[0043] c. The alloy melt flows evenly to the roller surface of the water-cooled casting roller through the distribution nozzle (the preheating temperature of the distribution nozzle is 1150℃), and the water-cooled casting roller quickly cools the alloy melt and casts it into shape. The cooling rate of the alloy melt is about 14000℃ / s. Its parameters are shown in Table 1 below.

[0044] Table 1 Main parameters of the experiment

[0045] Water-cooled casting roll speed 0.5m / s Alloy melt temperature 1150℃ Roller gap opening width 0.6mm Crucible temperature 1150℃ Water-cooled casting roll diameter 300mm Nozzle temperature 1150℃ Width of water-cooled casting roll 110mm Casting force About 20kN

[0046] like Figure 4 As shown in the figure, the 0.6 mm thick amorphous alloy strip was obtained in the experiment, and its microstructure photo and XRD curve are shown in Figure 5 As shown. Figure 4 , Figure 5 It can be seen that there is no crystal structure in the cast strip, which is a completely amorphous alloy.

[0047] The implementation results show that there is no wedge-shaped molten pool in the amorphous formation process of the present invention, and the alloy cooling rate is fast, the deformation is small, and the process is stable. The method of the present invention can be used to efficiently and continuously prepare thick-gauge amorphous plates and strips.

Claims

1. A method for continuously preparing thick-gauge amorphous alloy strips, characterized in that: The method sprays the alloy onto the surface of a water-cooled casting roll to form a metal shell that solidifies on one side, and then extrude the two metal shells through two water-cooled casting rolls to form a complete amorphous alloy strip. The continuous preparation method of thick-gauge amorphous alloy strip is carried out according to the following steps: (1) The heated and molten amorphous master alloy melt is transferred into a crucible and its temperature is stabilized so that it has a superheat of 100 to 300°C; (2) The amorphous master alloy melt is evenly sprayed onto the surfaces of the water-cooled casting rollers on both sides through a distribution nozzle, and the amorphous master alloy melt is cooled by heat conduction through the water-cooled casting roller and solidified on one side; (3) The amorphous alloy cooled on one side is extruded into an amorphous alloy strip by the rolling force of the water-cooled casting roll; The amorphous master alloy melt is distributed through a distribution nozzle, cooled and rolled into shape by two water-cooled casting rollers, but there is no wedge-shaped molten pool in the forming process; The device used in the method includes: a thermocouple, a crucible, an alloy melt, a flow distribution nozzle, and a water-cooled casting roller. The specific structure is as follows: The alloy raw material is placed in a crucible and smelted to form an alloy melt. The crucible is equipped with a thermocouple for temperature measurement. A distribution nozzle is closely arranged at the bottom of the crucible and is connected to the distribution nozzle through an outlet. The lower end of the distribution nozzle is placed in the roller gap between two horizontally opposed and counter-rotating water-cooled casting rollers and is in close contact with the water-cooled casting rollers. In the process of preparing the amorphous alloy, the alloy melt flows out through the nozzle of the distribution nozzle and is cooled by contact with the water-cooled casting roller, and is rolled into an alloy strip by the water-cooled casting roller. The main body of the distribution flow nozzle is composed of a rectangular plate section, a horizontal straight quadrangular prism wedge section and a horizontal straight triangular prism angle section arranged vertically, which are integrated from top to bottom. The longitudinal section of the rectangular plate section is a hollow flat rectangle, the longitudinal section of the straight quadrangular prism wedge section is a hollow inverted isosceles trapezoid, and the longitudinal section of the straight triangular prism angle section is an inverted isosceles triangle. The hollow parts of the rectangular plate section and the straight quadrangular prism wedge section are combined from top to bottom to form the inner cavity of the distribution flow nozzle. A narrow slit-shaped distribution flow nozzle nozzle is opened on the upper horizontal plane of the straight triangular prism angle section. The upper end of the inner cavity of the distribution flow nozzle is connected to the bottom outlet of the crucible, and the lower end of the inner cavity of the distribution flow nozzle is connected to the nozzle of the distribution flow nozzle. The outer periphery of the rectangular plate section and the straight quadrangular prism wedge section is covered with a heat preservation layer in accordance with the shape. The longitudinal section of the straight triangular prism tip section of the distribution nozzle is a sharp triangle. The amorphous master alloy melt flows out from both sides of the distribution nozzle and directly contacts the water-cooled casting roller. The tip of the distribution nozzle penetrates into the roller gap and occupies the central area of ​​the amorphous master alloy molten pool, making the flow of the amorphous master alloy close to laminar flow.

2. The method for continuously preparing thick-gauge amorphous alloy strip according to claim 1, characterized in that: The crucible and the flow nozzle are preheated, and the preheating method includes but is not limited to resistance wire heating or induction heating.

3. The continuous preparation method of thick-gauge amorphous alloy strip according to claim 1, characterized in that: The gap between the water-cooled casting rolls is 0.2~5 mm, and a certain casting force of 10~30kN is applied.

4. The method for continuously preparing thick-gauge amorphous alloy strip according to claim 1, characterized in that: The material of the flow nozzle is zirconium oxide, boron nitride or high-purity graphite which has a certain strength and does not react with the alloy melt.

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