Metal casting inflation method

Abstract

The invention provides a metal casting inflation method which comprises the following steps: loading a metal raw material to be processed into a smelting furnace, and sequentially carrying out vacuumizing treatment, first-stage gas replacement treatment, heating smelting treatment, second-stage gas replacement standing treatment, casting treatment, cooling treatment and third-stage gas replacement treatment to obtain a metal casting material. According to the method, by reasonably designing the gas replacement process in the metal casting process, the problems that in the casting process of ultra-pure 6N metal for semiconductors, gas consumption is large, the process control problem is solved, the ingot casting yield is low, and the ingot casting impurity content exceeds the standard are solved, so that the ingot casting impurity content is effectively controlled, and the production cost is reduced; the method is simple in steps, high in operability and suitable for popularization.

Description

Technical Field

[0001] The invention belongs to the technical field of metal smelting and casting, and relates to a method for metal smelting and casting and inflating. Background Art

[0002] Ultra-high purity 6N metal (99.9999%) is the raw material for manufacturing ultra-high purity metal sputtering targets for semiconductors. It is mainly used for integrated circuit chip wiring and is an indispensable raw material for high-quality chip production. In the production of ultra-high purity 6N metal ingots, the metal raw material heating, melting, and casting process requires multiple times of inflation, replacement, and cooling with high-purity gas.

[0003] The prior art discloses a fiber-reinforced metal suction casting pressure casting mold and a casting method, wherein the casting mold comprises a forming mold and a crucible mold, wherein an inner mold wrapped with fibers is placed in the forming mold, wherein the upper and lower top ends thereof each have a deep hole, and the surface near the end of the inner mold has small holes connected thereto, the top end of the forming mold is connected to an exhaust pipe, and the bottom end is connected to the crucible mold, and the casting method is to evacuate the casting mold and place it in a preheated ordinary tubular furnace and a crucible furnace, wherein the two furnaces are separated by a refractory plug, and when the crucible mold and the forming mold reach the set temperature, only the forming mold is continuously evacuated while air pressure is applied to the crucible mold for suction casting and pressure casting.

[0004] The prior art solution also discloses a multi-phase reinforced metal matrix composite material equipment, which is composed of an in-situ reaction synthesis reinforcement device and an external reinforcement melting and casting device. The in-situ reaction synthesis reinforcement device is composed of an induction furnace, a press, and a ball mushroom machine. The external reinforcement melting and casting device is composed of a workbench, a vertical column, an electrode holder, a water-cooled crystallizer, a combined water-cooled crystallizer, an electromagnetic stirrer, an ultrasonic vibrator, a feeder, a metal liquid tundish, a bottom water tank, and an ingot extraction device.

[0005] The prior art solution also discloses a method for preparing a high-strength and high-conductivity alloy. Based on the characteristics of copper with low strength and high conductivity, chromium and zirconium elements are added to the alloy to improve the alloy's structure and mechanical properties. After smelting, casting, solid solution, equal channel angular extrusion, cold rolling, aging treatment and other means, the grain size of the alloy is refined to the nanometer level, and a large amount of dispersed and fine second phase Cr phase and Cu5Zr phase are precipitated, which strongly hinder the movement of dislocations, thereby greatly improving the strength of the copper alloy and reducing the conductivity slightly.

[0006] However, for ultra-high purity 6N metal, manual inflation and replacement of gas cylinders are used in the original production process, which will cause high-purity gas consumption, frequent operation and easy substitution of air and other impurities, increase production costs, make process control difficult, reduce product quality, and have low ingot yield and excessive impurity content in ingots. Therefore, the production of ultra-high purity 6N metal ingots faces a large number of technical problems, such as reducing production costs and improving the internal quality of ingots. Therefore, it is urgent to design and develop a method for metal melting and inflation to overcome the defects of the existing technology and meet the needs of practical applications. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for metal melting and filling. In the present invention, by reasonably designing the gas replacement process in the metal melting and casting process, the problems of large gas consumption, process control problems, low ingot yield rate and excessive impurity content in the ingot in the melting and casting of ultra-high purity 6N metal for semiconductors are solved, so that the impurity content of the ingot is effectively controlled, the production cost is reduced, the steps are simple and the operability is strong, and it is suitable for promotion.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for metal casting and charging, the method comprising:

[0010] The metal raw materials to be processed are loaded into a smelting furnace, and are subjected to vacuum treatment, primary gas replacement treatment, temperature rise smelting treatment, secondary gas replacement static treatment, casting treatment, cooling treatment and tertiary gas replacement treatment in sequence to obtain metal castings.

[0011] In the present invention, by reasonably designing the gas replacement process in the metal melting and casting process, the problems of large gas consumption, process control problems, low ingot yield rate and excessive impurity content in the ingot during the melting and casting of ultra-high purity 6N metal for semiconductors are solved, so that the impurity content of the ingot is effectively controlled, the production cost is reduced, the steps are simple and the operability is strong, which is suitable for promotion.

[0012] It should be noted that the present invention adopts a combination of multiple treatments of vacuum treatment, primary gas replacement treatment, temperature melting treatment, secondary gas replacement static treatment, casting treatment, cooling treatment and tertiary gas replacement treatment in sequence, emphasizes multiple gas replacement processes, explores and improves the high vacuum medium frequency induction melting process, and finally forms a mature 6N metal ingot production gas replacement process, which solves the problems of high gas consumption, process control problems, low ingot yield and excessive impurity content in the ingot during the melting and casting of ultra-high purity 6N metal for semiconductors.

[0013] As a preferred technical solution of the present invention, before the metal raw materials to be processed are loaded into the smelting furnace, the furnace of the smelting furnace is cleaned.

[0014] Preferably, the cleaning process is performed under normal pressure.

[0015] It should be noted that the normal pressure in the present invention refers to a standard atmospheric pressure of 1013 hPa.

[0016] Preferably, the cleaning process uses a cleaning brush.

[0017] It should be noted that the material, shape and model of the cleaning brush are not particularly limited in the present invention, and those skilled in the art can make adaptive adjustments according to actual conditions. Among them, the cleaning process can clean the furnace of the smelting furnace under normal pressure and clean the air impurities floating on the surface of the furnace after the metal is loaded into the furnace.

[0018] Preferably, the cleaning treatment time is 10 to 15 minutes, for example, it can be 10 minutes, 10.5 minutes, 11 minutes, 11.5 minutes, 12 minutes, 12.5 minutes, 13 minutes, 13.5 minutes, 14 minutes, 14.5 minutes, 15 minutes, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] As a preferred technical solution of the present invention, the vacuum treatment is performed by a vacuum pump group.

[0020] It should be noted that the present invention does not specifically limit the number, shape and model of the vacuum pump group, and those skilled in the art can make adaptive adjustments according to actual conditions. Among them, the vacuum pumps can be connected in series.

[0021] Preferably, after the vacuum treatment, the vacuum degree in the smelting furnace is 6.6×10 -2 ~6.7×10 - 2 bar, for example, could be 6.6×10 -2 bar, 6.61×10 -2 bar, 6.62×10 -2 bar, 6.63×10 -2 bar, 6.64×10 - 2 bar, 6.65×10 -2 bar, 6.66×10 -2 bar, 6.67×10 -2 bar, 6.68×10 -2 bar, 6.69×10 -2 bar, 6.7×10-2 bar, etc., but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] The vacuum degree in the smelting furnace of the present invention is 6.6×10 -2 ~6.7×10 -2 bar, because under this vacuum degree, the gas and low-melting-point impurities in the metal during the smelting process can be volatilized and discharged. If it is not within this range, the gas and low-melting-point impurities in the metal during the smelting process cannot be volatilized and discharged, resulting in a decrease in the purity of the molten metal.

[0023] As a preferred technical solution of the present invention, the primary gas replacement treatment includes at least two replacement processes, for example, 2 times, 3 times, 4 times, 5 times, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the gas used in the replacement process is argon.

[0025] It should be noted that the primary gas replacement treatment in the present invention includes at least two replacement processes. Multiple replacement processes can discharge the gas remaining in the furnace to ensure that the furnace is clean.

[0026] It should be noted that the argon gas in the present invention is high-purity argon gas, and its high purity means that the content of bottled high-purity argon gas reaches 5N-99.999% or more.

[0027] As a preferred technical solution of the present invention, the heating temperature of the heating smelting treatment is 1200-1400°C, for example, it can be 1200°C, 1220°C, 1240°C, 1260°C, 1280°C, 1300°C, 1320°C, 1340°C, 1360°C, 1380°C, 1400°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] As a preferred technical solution of the present invention, the secondary gas replacement static treatment includes at least one replacement process, for example, it can be 1 time, 2 times, 3 times, 4 times, 5 times, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, the gas used in the replacement process is argon.

[0030] It should be noted that the secondary gas replacement static treatment in the present invention includes at least one replacement process, which is mainly aimed at the porosity defects existing inside the ingot. The main reason is that the molten metal temperature is high and the pouring speed is fast, and it is difficult to compensate for the shrinkage of the liquid metal during casting and solidification. The present invention adjusts the temperature and speed of the molten metal during casting and adopts multiple replacements to promote the volatilization of impurity elements again, thereby eliminating internal defects of the ingot and effectively reducing shrinkage and shrinkage pores on the surface of the ingot, so as to ensure the purity of the ingot.

[0031] Preferably, the replacement time of the replacement process is 5 to 6 minutes, for example, it can be 5 minutes, 5.1 minutes, 5.2 minutes, 5.3 minutes, 5.4 minutes, 5.5 minutes, 5.6 minutes, 5.7 minutes, 5.8 minutes, 5.9 minutes, 6 minutes, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] The replacement time of the replacement process in the present invention is 5 to 6 minutes because within this range, the gas and low-melting-point impurities in the metal during the smelting process can be volatilized and discharged. If it is not within this range, the gas and low-melting-point impurities in the metal during the smelting process cannot be volatilized and discharged, resulting in a decrease in the purity of the molten metal.

[0033] As a preferred technical solution of the present invention, the replacement process is carried out in the following manner:

[0034] Argon gas is filled into the smelting furnace until the vacuum degree in the smelting furnace reaches a certain range.

[0035] As a preferred technical solution of the present invention, the certain range is 200-210Pa, for example, it can be 200Pa, 201Pa, 202Pa, 203Pa, 204Pa, 205Pa, 206Pa, 207Pa, 208Pa, 209Pa, 210Pa, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the filling amount of argon gas is 2000-2100Pa, for example, it can be 2000Pa, 2010Pa, 2020Pa, 2030Pa, 2040Pa, 2050Pa, 2060Pa, 2070Pa, 2080Pa, 2090Pa, 2100Pa, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] In the present invention, the certain range is 200-210Pa and the filling amount of argon is 2000-2100Pa, because within this range, the gas and low-melting-point impurities in the metal during the smelting process can be volatilized and discharged. If it is not within this range, the gas and low-melting-point impurities in the metal during the smelting process cannot be volatilized and discharged, resulting in reduced purity of the molten metal, or the elements in the metal alloy cannot be controlled within the required range, resulting in defective products.

[0038] As a preferred technical solution of the present invention, before the casting process, the temperature of the metal liquid surface in the smelting furnace needs to be measured by infrared, and when the metal liquid surface temperature reaches a certain temperature, the casting process is carried out.

[0039] It should be noted that the specific instruments and measurement methods used in the infrared measurement of the present invention are not particularly limited, and those skilled in the art can make adaptive adjustments according to actual conditions. In view of the problem of excessive impurity content in the ingot, by comparing the activity and fugacity of different elemental elements under the same atmospheric pressure, the standing time of the metal liquid and the temperature adjustment within a specific range are determined, and the impurity elements are volatilized as much as possible through the replacement process to control the impurity element content; the liquid viscosity is reduced to the maximum extent to ensure smooth solidification and shrinkage compensation, and eliminate internal shrinkage cavities.

[0040] Preferably, the certain temperature is 1200-1300°C, for example, it may be 1200°C, 1210°C, 1220°C, 1230°C, 1240°C, 1250°C, 1260°C, 1270°C, 1280°C, 1290°C, 1300°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] The certain temperature in the present invention is 1200-1300° C. because within this range, the gas and low-melting-point impurities in the metal during the smelting process can be volatilized and discharged. If it is not within this range, the gas and low-melting-point impurities in the metal during the smelting process cannot be volatilized and discharged, resulting in reduced purity of the molten metal, or the elements in the metal alloy cannot be controlled within the required range, resulting in defective products.

[0042] As a preferred technical solution of the present invention, the cooling treatment is a natural cooling treatment.

[0043] Preferably, after the cooling treatment, the temperature in the smelting furnace is 500-800°C, for example, it can be 500°C, 520°C, 550°C, 580°C, 600°C, 630°C, 680°C, 700°C, 730°C, 760°C, 800°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] The temperature in the smelting furnace in the present invention is 500-800°C because within this range, the cooling of the metal ingot in the furnace can be accelerated to prevent the metal ingot from having defects such as shrinkage cavities, cold shuts, and hot cracks. If it is not within this range, the cooling of the metal ingot in the furnace will be slow, and the metal ingot will be prone to defects such as shrinkage cavities, cold shuts, and hot cracks.

[0045] Preferably, the three-stage gas replacement treatment includes at least one replacement process, for example, 1 time, 2 times, 3 times, 4 times, 5 times, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] Preferably, the gas used in the replacement process is argon.

[0047] It should be noted that in the present invention, after the casting is completed, the smelting furnace and the metal in the furnace are naturally cooled to 500-800°C, and the three-stage gas replacement treatment is started, which can mainly adjust the inflation volume, and adjust the inflation cooling volume according to the pouring liquid level and the ingot crystallization cooling conditions, reduce the ingot shrinkage and looseness, and improve the ingot yield rate.

[0048] Exemplarily, a method for metal casting and charging in the present invention specifically includes:

[0049] The metal raw materials to be processed are loaded into a smelting furnace, and are subjected to vacuum treatment, primary gas replacement treatment, temperature rise smelting treatment, secondary gas replacement static treatment, casting treatment, cooling treatment and tertiary gas replacement treatment in sequence to obtain metal castings.

[0050] Before the metal raw materials to be processed are loaded into the smelting furnace, the furnace of the smelting furnace is cleaned. The cleaning process is carried out under normal pressure. A cleaning brush is used for the cleaning process. The cleaning process takes 10 to 15 minutes.

[0051] The vacuum treatment is carried out by a vacuum pump group. After the vacuum treatment, the vacuum degree in the smelting furnace is 6.6×10 -2 ~6.7×10 -2 bar.

[0052] The primary gas replacement treatment includes at least two replacement processes, and the gas used in the replacement process is argon.

[0053] The heating temperature of the heating smelting process is 1200-1400°C.

[0054] The secondary gas replacement static treatment includes at least one replacement process, the gas used in the replacement process is argon, and the replacement time of the replacement process is 5 to 6 minutes. The replacement process is carried out in the following manner:

[0055] The argon gas is charged into the smelting furnace until the vacuum degree in the smelting furnace reaches a certain range, wherein the certain range is 200-210 Pa, and the charging amount of the argon gas is 2000-2100 Pa.

[0056] Before the casting process, the temperature of the metal liquid surface in the smelting furnace needs to be measured by infrared. When the temperature of the metal liquid surface reaches a certain temperature, the casting process is carried out. The certain temperature is 1200-1300°C.

[0057] The cooling treatment is a natural cooling treatment. After the cooling treatment, the temperature in the smelting furnace is 500-800° C. The three-stage gas replacement treatment includes at least one replacement process, and the gas used in the replacement process is argon.

[0058] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] In the present invention, by reasonably designing the gas replacement process in the metal melting and casting process, the problems of large gas consumption, process control problems, low ingot yield rate and excessive impurity content in the ingot during the melting and casting of ultra-high purity 6N metal for semiconductors are solved, so that the impurity content of the ingot is effectively controlled, the production cost is reduced, the steps are simple and the operability is strong, which is suitable for promotion. DETAILED DESCRIPTION

[0061] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0062] Example 1

[0063] This embodiment provides a method for metal casting and inflating, wherein:

[0064] The metal raw materials to be processed are loaded into a smelting furnace, and are subjected to vacuum treatment, primary gas replacement treatment, temperature rise smelting treatment, secondary gas replacement static treatment, casting treatment, cooling treatment and tertiary gas replacement treatment in sequence to obtain metal castings.

[0065] Before the metal raw materials to be processed are loaded into the smelting furnace, the furnace of the smelting furnace is cleaned. The cleaning process is carried out under normal pressure. A cleaning brush is used for the cleaning process. The cleaning process takes 10 minutes.

[0066] The vacuum treatment is carried out by a vacuum pump group. After the vacuum treatment, the vacuum degree in the melting furnace is 6.6×10 - 2bar.

[0067] The primary gas replacement treatment includes two replacement processes, and the gas used in the replacement process is argon.

[0068] The heating temperature of the heating smelting process is 1200°C.

[0069] The secondary gas replacement static treatment includes a replacement process, the gas used in the replacement process is argon, and the replacement time of the replacement process is 5 minutes.

[0070] The replacement process is carried out as follows:

[0071] Argon is filled into the melting furnace until the vacuum degree in the melting furnace reaches 210Pa, and the filling amount of argon is 2000Pa.

[0072] Before the casting process, the temperature of the metal liquid surface in the smelting furnace needs to be measured by infrared. When the metal liquid surface temperature reaches a certain temperature, the casting process is carried out. The certain temperature is 1200℃.

[0073] The cooling treatment is a natural cooling treatment. After the cooling treatment, the temperature in the smelting furnace is 800° C. The three-stage gas replacement treatment includes a replacement process, and the gas used in the replacement process is argon.

[0074] Example 2

[0075] This embodiment provides a method for metal casting and inflating, wherein:

[0076] The metal raw materials to be processed are loaded into a smelting furnace, and are subjected to vacuum treatment, primary gas replacement treatment, temperature rise smelting treatment, secondary gas replacement static treatment, casting treatment, cooling treatment and tertiary gas replacement treatment in sequence to obtain metal castings.

[0077] Before the metal raw materials to be processed are loaded into the smelting furnace, the furnace of the smelting furnace is cleaned. The cleaning process is carried out under normal pressure. A cleaning brush is used for the cleaning process. The cleaning process takes 12 minutes.

[0078] The vacuum treatment is carried out by a vacuum pump group. After the vacuum treatment, the vacuum degree in the melting furnace is 6.65×10 - 2 bar.

[0079] The primary gas replacement treatment includes three replacement processes, and the gas used in the replacement process is argon.

[0080] The heating temperature of the heating smelting process is 1300°C.

[0081] The secondary gas replacement static treatment includes two replacement processes. The gas used in the replacement process is argon, and the replacement time of the replacement process is 5.6 minutes.

[0082] The replacement process is carried out as follows:

[0083] Argon is filled into the smelting furnace until the vacuum degree in the smelting furnace reaches 206Pa, and the filling amount of argon is 2050Pa.

[0084] Before the casting process, the temperature of the metal liquid surface in the smelting furnace needs to be measured by infrared. When the metal liquid surface temperature reaches a certain temperature, the casting process is carried out. The certain temperature is 1250℃.

[0085] The cooling treatment is a natural cooling treatment. After the cooling treatment, the temperature in the smelting furnace is 600°C. The three-stage gas replacement treatment includes two replacement processes, and the gas used in the replacement process is argon.

[0086] Example 3

[0087] This embodiment provides a method for metal casting and inflating, wherein:

[0088] The metal raw materials to be processed are loaded into a smelting furnace, and are subjected to vacuum treatment, primary gas replacement treatment, temperature rise smelting treatment, secondary gas replacement static treatment, casting treatment, cooling treatment and tertiary gas replacement treatment in sequence to obtain metal castings.

[0089] Before the metal raw materials to be processed are loaded into the smelting furnace, the furnace of the smelting furnace is cleaned. The cleaning process is carried out under normal pressure. A cleaning brush is used for the cleaning process. The cleaning process takes 15 minutes.

[0090] The vacuum treatment is carried out by a vacuum pump group. After the vacuum treatment, the vacuum degree in the melting furnace is 6.7×10 - 2 bar.

[0091] The primary gas replacement treatment includes four replacement processes, and the gas used in the replacement process is argon.

[0092] The heating temperature of the heating smelting process is 1400°C.

[0093] The secondary gas replacement static treatment includes three replacement processes. The gas used in the replacement process is argon, and the replacement time of the replacement process is 6 minutes.

[0094] The replacement process is carried out as follows:

[0095] Argon is filled into the melting furnace until the vacuum degree in the melting furnace reaches 200Pa, and the filling amount of argon is 2100Pa.

[0096] Before the casting process, the temperature of the metal liquid surface in the smelting furnace needs to be measured by infrared. When the metal liquid surface temperature reaches a certain temperature, the casting process is carried out. The certain temperature is 1300℃.

[0097] The cooling treatment is a natural cooling treatment. After the cooling treatment, the temperature in the smelting furnace is 500° C. The three-stage gas replacement treatment includes three replacement processes, and the gas used in the replacement process is argon.

[0098] Example 4

[0099] This embodiment provides a method for metal casting and inflating. The difference from the first embodiment is that the vacuum degree in the smelting furnace is 6.5×10 -2 bar, and other parameters and conditions are the same as those in Example 1.

[0100] Example 5

[0101] This embodiment provides a method for metal casting and filling. The difference from the first embodiment is that the vacuum degree in the melting furnace is 6.8×10 -2 bar, and other parameters and conditions are the same as those in Example 1.

[0102] Example 6

[0103] This embodiment provides a method for metal melting and inflating. The difference from Embodiment 1 is that the certain range is 190Pa, and the other parameters and conditions are the same as those in Embodiment 1.

[0104] Example 7

[0105] This embodiment provides a method for metal melting and inflating. The difference from Embodiment 1 is that the certain range is 220Pa, and the other parameters and conditions are the same as those in Embodiment 1.

[0106] Example 8

[0107] This embodiment provides a method for metal melting and filling. The difference from Embodiment 1 is that the certain temperature is 1150° C., and the other parameters and conditions are the same as those in Embodiment 1.

[0108] Example 9

[0109] This embodiment provides a method for metal melting and inflating. The difference from Embodiment 1 is that the certain temperature is 1350° C., and the other parameters and conditions are the same as those in Embodiment 1.

[0110] Example 10

[0111] This embodiment provides a method for metal melting and inflating. The difference from Embodiment 1 is that after cooling, the temperature in the smelting furnace is 450° C., and the other parameters and conditions are the same as those in Embodiment 1.

[0112] Embodiment 11

[0113] This embodiment provides a method for metal melting and inflating. The difference from Embodiment 1 is that after cooling, the temperature in the smelting furnace is 850° C., and the other parameters and conditions are the same as those in Embodiment 1.

[0114] Comparative Example 1

[0115] This comparative example provides a method for metal melting and filling. The difference from Example 1 is that there is no secondary gas replacement static treatment, and the other parameters and conditions are the same as those in Example 1.

[0116] Comparative Example 2

[0117] This comparative example provides a method for metal melting and filling. The difference from Example 1 is that there is no three-stage gas replacement treatment, and the other parameters and conditions are the same as those in Example 1.

[0118] The metal castings in the above embodiments and comparative examples were sampled and tested at the upper, middle and lower parts using GDMS, OES and LECO testing equipment. The results are shown in Table 1 below.

[0119] Table 1 Test results of metal castings in the embodiments and comparative examples

[0120]

[0121] From Table 1 above, we know that:

[0122] In summary, the present invention solves the problems of large gas consumption, process control problems, low ingot yield rate and excessive impurity content in the process of melting and casting ultra-high purity 6N metal for semiconductors by reasonably designing the gas replacement process in the metal melting and casting process, so that the impurity content of the ingot is effectively controlled, the production cost is reduced, the steps are simple and the operability is strong, and it is suitable for promotion.

[0123] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0124] The present invention illustrates the detailed method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed method, that is, it does not mean that the present invention must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for metal casting and inflating, characterized in that: The method comprises: The metal raw materials to be processed are loaded into a smelting furnace, and are sequentially subjected to vacuum treatment, primary gas replacement treatment, temperature rise smelting treatment, secondary gas replacement static treatment, casting treatment, cooling treatment and tertiary gas replacement treatment to obtain metal castings.

2. The method according to claim 1, characterized in that Before the metal raw materials to be processed are loaded into the smelting furnace, the furnace of the smelting furnace is cleaned; Preferably, the cleaning process is carried out under normal pressure; Preferably, the cleaning process uses a cleaning brush; Preferably, the cleaning process takes 10 to 15 minutes.

3. The method according to claim 1 or 2, characterized in that: The vacuuming treatment is performed by a vacuum pump set; Preferably, after the vacuum treatment, the vacuum degree in the smelting furnace is 6.6×10 -2 ~6.7×10 -2 bar.

4. The method according to any one of claims 1 to 3, characterized in that: The primary gas replacement process includes at least two replacement processes; Preferably, the gas used in the replacement process is argon.

5. The method according to any one of claims 1 to 4, characterized in that: The heating temperature of the heating smelting process is 1200-1400°C.

6. The method according to any one of claims 1 to 5, characterized in that: The secondary gas replacement static treatment includes at least one replacement process; Preferably, the gas used in the replacement process is argon; Preferably, the replacement time of the replacement process is 5 to 6 minutes.

7. The method according to claim 6, characterized in that The replacement process is carried out in the following manner: Argon gas is filled into the smelting furnace until the vacuum degree in the smelting furnace reaches a certain range.

8. The method according to claim 7, characterized in that The certain range is 200-210 Pa; Preferably, the filling amount of the argon gas is 2000-2100Pa.

9. The method according to any one of claims 1 to 8, characterized in that: Before the casting process, the temperature of the metal liquid surface in the smelting furnace needs to be measured by infrared, and when the temperature of the metal liquid surface reaches a certain temperature, the casting process is carried out; Preferably, the certain temperature is 1200-1300°C.

10. The method according to any one of claims 1 to 9, characterized in that: The cooling process is a natural cooling process; Preferably, after the cooling treatment, the temperature in the smelting furnace is 500-800°C; Preferably, the three-stage gas replacement treatment includes at least one replacement process; Preferably, the gas used in the replacement process is argon.

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