Method for preparing beryllium-copper master alloy from waste beryllium scraps

Abstract

The invention provides a method for preparing beryllium-copper master alloy from waste beryllium scraps, and belongs to the technical field of beryllium-copper alloys.The method comprises the steps that after beryllium scraps, waste beryllium-copper scraps and electrolytic copper are cleaned, the beryllium scraps, the waste beryllium-copper scraps and the electrolytic copper are put into a copper crucible in a vacuum suspension smelting furnace; within 25-35 min, vacuumizing is conducted by stages to 3-6 * 10 <-3 > Pa, argon is introduced into the vacuum suspension smelting furnace till the pressure in the vacuum suspension smelting furnace is 4-7 * 10 <-2 > Pa, the heating power is increased by stages, smelting is conducted, and a metal melt is obtained; and after the metal melt in the copper crucible is filtered and cast into a mold, the heating power is reduced to 0 kw within 25-35 s, cooling is conducted for 25-35 min, and the beryllium copper master alloy is obtained. On the premise that the Be content in the prepared beryllium-copper master alloy meets the production requirement of the beryllium-copper alloy, the current situation of beryllium resource shortage is relieved, the production time is shortened, and the production cost is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of beryllium copper alloys, and in particular relates to a method for preparing a beryllium copper master alloy from waste beryllium chips. Background Art

[0002] Beryllium copper alloy refers to an alloy with a beryllium content of 0.2-2.8wt%. This alloy has good mechanical properties and corrosion resistance and is widely used in aerospace, equipment manufacturing and other fields. With the development of aerospace and equipment manufacturing industries, the demand for high-strength and corrosion-resistant materials continues to increase, which provides huge opportunities for the beryllium copper alloy market. However, in the production of beryllium copper alloy, beryllium copper master alloy with stable quality and in line with actual production is the prerequisite for the production of beryllium copper alloy.

[0003] The existing method for preparing beryllium copper master alloy is mainly an atmospheric non-consumable arc melting method, which adopts atmospheric connected graphite electrode production, the main raw materials are beryllium oxide and graphite, and the beryllium copper master alloy is obtained by a carbon reduction method. However, since beryllium is the lightest metal element, it is very easy to volatilize during smelting, which reduces the qualified rate of the product. At the same time, the raw material contains graphite, which combines with carbon element to form beryllium carbide during the beryllium generation process, resulting in the beryllium copper master alloy containing more beryllium carbide, which seriously affects the subsequent product production and further reduces the qualified rate of the product. In addition, during the thermal decomposition process, a certain amount of carbon monoxide will be generated, and the risk of carbon monoxide leakage needs to be considered in actual production, resulting in an increase in production safety costs. Since the existing method for preparing beryllium copper master alloy needs to consider both the carbon reduction process and the smelting effect of metal beryllium and copper, the process is too complicated and each part is difficult to accurately control in actual production. A vacuum arc furnace is used, and this type of furnace consumes too much energy in the actual production process. Therefore, the beryllium copper master alloy prepared by the existing atmospheric non-consumable arc melting method has a high impurity content, a low product qualification rate, a complex process and a high production cost. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing beryllium copper master alloy from waste beryllium chips, which, under the premise of ensuring that the Be content in the beryllium copper master alloy meets the production demand of beryllium copper alloy, alleviates the current situation of tight beryllium resources, shortens the production time and saves the production cost.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing beryllium copper master alloy from waste beryllium chips, the method comprising the following steps:

[0007] Step S1, washing beryllium scraps, waste beryllium copper scraps and electrolytic copper, and placing them into a copper crucible in a vacuum suspension furnace;

[0008] Step S2: within 25 to 35 minutes, vacuumize in stages to 3 to 6 × 10-3 After that, argon gas is introduced into the vacuum suspension furnace until the pressure in the vacuum suspension furnace reaches 4-7×10 -2 After Pa, the heating power is increased in stages to carry out smelting and obtain a molten metal;

[0009] Step S3: After filtering the molten metal in the copper crucible and casting it into a mold, the heating power is reduced to 0 kW within 25 to 35 seconds, and the mixture is cooled for 25 to 35 minutes to obtain a beryllium copper master alloy.

[0010] Furthermore, in the step S1, the mass ratio of the waste beryllium chips, the waste beryllium copper chips and the electrolytic copper is 8-13:54-56:33-36.

[0011] Furthermore, in step S2, the specific process of vacuuming in stages includes:

[0012] First, use a mechanical pump to evacuate the air to 0.7-1.2×10 2 Pa, and then use Roots pump to evacuate, and continue to evacuate to 1.8-2.2Pa within 12-15min, and finally use molecular pump to evacuate, and continue to evacuate to 3-6×10 -3 Pa. This is to avoid oxidation of beryllium in waste beryllium scraps and waste beryllium copper scraps during the smelting process, resulting in a high impurity content in the metal melt, thereby reducing the quality of the beryllium copper master alloy and the qualified rate of the beryllium copper master alloy. At the same time, the melting points of waste beryllium scraps, waste beryllium copper scraps and electrolytic copper are reduced, and the energy consumption in the smelting process is reduced on the basis of ensuring the material melting efficiency.

[0013] Furthermore, in step S2, the specific process of increasing the heating power in stages includes:

[0014] The first stage: increase the heating power to 60-80 kW at a rate of 50-90 kW / min and maintain for 50-70 seconds;

[0015] The second stage: continue to increase the heating power to 160-190 kW at a rate of 50-90 kW / min and maintain it for 170-190 seconds;

[0016] The third stage: increase the heating power to 240-260 kW at a rate of 50-90 kW / min.

[0017] The present invention realizes uniform heating of waste beryllium chips, electrolytic copper and waste beryllium copper chips through the preheating process in the first stage; fully melts the waste beryllium chips through the melting process in the second stage; and fully melts the electrolytic copper and waste beryllium copper chips through the melting process in the third stage, thereby reducing the impurity content in the metal melt.

[0018] Furthermore, in step S2, the specific process of increasing the heating power in stages also includes:

[0019] The fourth stage: when the heating power is increased to 240-260kw, if there is unmelted raw material in the molten metal, the heating power is increased to the limit power of the vacuum suspension furnace at a rate of 50-90kw / min and maintained for 10-15min, thereby ensuring that the impurity content in the molten metal is low and the alloy melt composition is evenly distributed, thereby improving the quality of the cast product (i.e., beryllium copper master alloy) and ensuring the qualified rate of beryllium copper master alloy.

[0020] Furthermore, the maximum power of the vacuum suspension furnace is 360kw.

[0021] Furthermore, the rate is 60-70 kw / min, which is convenient for fully melting the waste beryllium chips, waste beryllium copper chips and electrolytic copper, and reduces the number of refractory inclusions in the alloy.

[0022] Furthermore, the smelting and casting are both carried out under water circulation at 20-30° C., which prevents the crucible from being melted due to excessive temperature.

[0023] In summary, the technical solution of the present invention has the following technical effects:

[0024] The present invention utilizes a vacuum suspension smelting furnace, realizes vacuum suspension smelting of waste beryllium chips, waste beryllium copper chips and electrolytic copper by staged vacuuming and staged heating power increase, avoids the volatilization of beryllium during the smelting process, reduces the generation of impurities such as beryllium carbide, avoids the contact between the material and the crucible, improves the purity of the metal melt, avoids the heterogeneous nucleation of the beryllium copper master alloy, improves the uniformity of the beryllium copper master alloy structure, and ensures the qualified rate of the beryllium copper master alloy products; on the other hand, while ensuring the smelting efficiency and product quality, simplifies the production process and shortens the time. The invention shortens production time and reduces energy consumption, thus reducing production cost. The invention adopts waste beryllium scraps and waste beryllium copper scraps, improves resource utilization efficiency, alleviates the shortage of beryllium resources, and saves production cost. The invention removes beryllium oxide inclusions and unmelted materials generated by waste beryllium scraps and waste beryllium copper scraps in the smelting process through filtering and casting, thereby ensuring the qualified rate of beryllium copper master alloy products. The Be content in the beryllium copper master alloy of the invention can reach 9.5-10.5wt%, and the Fe and Al impurity contents are both lower than 1500ppm, thus meeting the production demand of beryllium copper alloy. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1:

[0027] Step S1, washing beryllium scraps, beryllium copper scraps and electrolytic copper in a mass ratio of 11:55:34, and putting them into a copper crucible in a vacuum suspension furnace.

[0028] Step S2: Under the condition of water circulation at 25°C, vacuum is firstly drawn by a mechanical pump to a pressure of 1.0×10 2 Pa, and then evacuate with a Roots pump, and continue to evacuate to 2.0Pa within 13min, and finally evacuate with a molecular pump, and continue to evacuate to 5×10 -3 Pa, argon gas was introduced into the vacuum suspension furnace until the pressure in the vacuum suspension furnace reached 5.5×10 -2 After Pa, turn the power adjustment knob to increase the heating power to 70kw at a rate of 60kw / min. The beryllium chips in the crucible will first turn red and show a melting trend, which is maintained for 60s. Then, increase the heating power to 180kw at a rate of 60kw / min and maintain for 180s to prevent the material from splashing due to too fast power increase, and ensure that the material in the crucible melts slowly, so that all large pieces of material are melted. Continue to increase the heating power to 250kw at a rate of 60kw / min to detect whether there is any unmelted raw material in the metal melt. If not, end the process to obtain a metal melt. If so, increase the heating power to 360kw at a rate of 60kw / min and maintain for 12min to gradually increase the tumbling degree of the metal melt and promote the uniformity of the composition of the metal melt to obtain a metal melt.

[0029] Step S3, turning over the copper crucible, filtering the molten metal in the copper crucible and casting it into a mold, reducing the heating power to 0 kW within 30 seconds, cooling for 30 minutes, and obtaining a beryllium copper master alloy ingot.

[0030] The qualified rate of the beryllium copper master alloy ingot of this embodiment is 98.62%. By detecting the composition information of the upper, middle and lower parts of the beryllium copper master alloy ingot, the composition content of different parts of the beryllium copper master alloy ingot of this embodiment is shown in Table 1:

[0031] Table 1 Component contents of different parts of beryllium copper master alloy ingot of Example 1

[0032]

[0033] Embodiment 2:

[0034] Step S1, washing beryllium scraps, waste beryllium copper scraps and electrolytic copper in a mass ratio of 13:54:33, and putting them into a copper crucible in a vacuum suspension furnace.

[0035] Step S2: Under the condition of water circulation at 30°C, vacuum is firstly drawn by a mechanical pump to a pressure of 1.2×10 2 Pa, and then use Roots pump to evacuate, and continue to evacuate to 2.2Pa within 15min, and finally use molecular pump to evacuate, and continue to evacuate to 6×10 -3 Pa, argon gas was introduced into the vacuum suspension furnace until the pressure in the vacuum suspension furnace reached 7×10 -2 After Pa, turn the power adjustment knob to increase the heating power to 80kw at a rate of 90kw / min. The beryllium chips in the crucible will first turn red and show a melting trend, which is maintained for 70s. Then, increase the heating power to 190kw at a rate of 90kw / min and maintain for 190s to prevent the material from splashing due to too fast power increase, and ensure that the material in the crucible melts slowly, so that all large pieces of material are melted. Continue to increase the heating power to 260kw at a rate of 90kw / min to detect whether there are unmelted raw materials in the metal melt. If not, end the process to obtain a metal melt. If so, increase the heating power to 360kw at a rate of 90kw / min and maintain for 15min to gradually increase the tumbling degree of the metal melt and promote the uniformity of the composition of the metal melt to obtain a metal melt.

[0036] Step S3, turning over the copper crucible, filtering the molten metal in the copper crucible and casting it into a mold, reducing the heating power to 0 kW within 35 seconds, cooling for 35 minutes, and obtaining a beryllium copper master alloy ingot.

[0037] The qualified rate of the beryllium copper master alloy ingot of this embodiment is 99.20%. By detecting the composition information of the upper, middle and lower parts of the beryllium copper master alloy ingot, the composition content of different parts of the beryllium copper master alloy ingot of this embodiment is shown in Table 2:

[0038] Table 2 Component contents of different parts of beryllium copper master alloy ingot of Example 2

[0039]

[0040] Embodiment 3:

[0041] Step S1, washing waste beryllium chips, waste beryllium copper chips and electrolytic copper in a mass ratio of 8:56:36, and putting them into a copper crucible in a vacuum suspension furnace.

[0042] Step S2: Under the condition of water circulation at 20°C, vacuum is firstly drawn by a mechanical pump to a pressure of 0.7×10 2 Pa, and then use Roots pump to evacuate, and continue to evacuate to 1.8Pa within 12min, and finally use molecular pump to evacuate, and continue to evacuate to 3×10 -3 Pa, argon gas was introduced into the vacuum suspension furnace until the pressure in the vacuum suspension furnace reached 4×10 -2 After Pa,

[0043] Turn the power adjustment knob and increase the heating power to 60kw at a rate of 50kw / min. The beryllium chips in the crucible will first turn red and show a melting trend, which is maintained for 50s. Then, increase the heating power to 160kw at a rate of 50kw / min and maintain for 170s to prevent the material from splashing due to excessive power increase and to ensure that the material in the crucible melts slowly so that all large pieces of material are melted. Continue to increase the heating power to 240kw at a rate of 50kw / min to detect whether there are any unmelted raw materials in the metal melt. If not, end the process to obtain a metal melt. If so, increase the heating power to 360kw at a rate of 50kw / min and maintain for 10min to gradually increase the tumbling degree of the metal melt and promote the uniformity of the composition of the metal melt to obtain a metal melt.

[0044] Step S3, turning over the copper crucible, filtering the molten metal in the copper crucible and casting it into a mold, reducing the heating power to 0 kW within 25 seconds, cooling for 25 minutes, and obtaining a beryllium copper master alloy ingot.

[0045] The qualified rate of the beryllium copper master alloy ingot of this embodiment is 98.72%. By detecting the composition information of the upper, middle and lower parts of the beryllium copper master alloy ingot, the composition content of different parts of the beryllium copper master alloy ingot of this embodiment is shown in Table 3:

[0046] Table 3 Component contents of different parts of beryllium copper master alloy ingot of Example 3

[0047]

[0048] Please note that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all belong to the scope of protection of the present application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims.

Claims

1. A method for preparing beryllium copper master alloy from waste beryllium chips, characterized in that: The method comprises the following steps: Step S1, washing beryllium scraps, waste beryllium copper scraps and electrolytic copper, and placing them into a copper crucible in a vacuum suspension furnace; Step S2: within 25 to 35 minutes, vacuumize in stages to 3 to 6 × 10 -3 After that, argon gas is introduced into the vacuum suspension furnace until the pressure in the vacuum suspension furnace reaches 4-7×10 -2 After Pa, the heating power is increased in stages to carry out smelting and obtain a molten metal; Step S3: After filtering the molten metal in the copper crucible and casting it into a mold, the heating power is reduced to 0 kW within 25 to 35 seconds, and the mixture is cooled for 25 to 35 minutes to obtain a beryllium copper master alloy.

2. The method according to claim 1, characterized in that In the step S1, the mass ratio of the waste beryllium chips, waste beryllium copper chips and electrolytic copper is 8-13:54-56:33-36.

3. The method according to claim 2, characterized in that In step S2, the specific process of vacuuming in stages includes: First, use a mechanical pump to evacuate the air to 0.7-1.2×10 2 Pa, and then use Roots pump to evacuate, and continue to evacuate to 1.8-2.2Pa within 12-15min, and finally use molecular pump to evacuate, and continue to evacuate to 3-6×10 -3 Pa.

4. The method according to claim 3, characterized in that In step S2, the specific process of increasing the heating power in stages includes: The first stage: increase the heating power to 60-80 kW at a rate of 50-90 kW / min and maintain for 50-70 seconds; The second stage: continue to increase the heating power to 160-190 kW at a rate of 50-90 kW / min and maintain it for 170-190 seconds; The third stage: increase the heating power to 240-260 kW at a rate of 50-90 kW / min.

5. The method according to claim 4, characterized in that In step S2, the specific process of increasing the heating power in stages also includes: The fourth stage: when the heating power is increased to 240-260kw, if there are unmelted raw materials in the metal melt, the heating power is increased to the limit power of the vacuum suspension furnace at a rate of 50-90kw / min and maintained for 10-15min.

6. The method according to claim 5, characterized in that The maximum power of the vacuum suspension furnace is 360kw.

7. The method according to claim 6, characterized in that The speed is 60-70 kw / min.

8. The method according to any one of claims 1 to 7, characterized in that: The smelting and casting are both carried out under water circulation at 20-30°C.

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