Method for preparing mother alloy for beryllium bronze from beryllium copper residual material

Abstract

The invention discloses a method for preparing a mother alloy for beryllium bronze from beryllium copper residues, and belongs to the technical field of beryllium bronze preparation. The method comprises the following steps: crushing a filter screen bonding material and a furnace bonding material, and screening to obtain particles; the screened particles of the binding material and the binding furnace material are pressed, and blocky beryllium copper residual materials are obtained; the preparation method comprises the following steps: preparing blocky beryllium copper residual materials and electrolytic copper according to a beryllium copper master alloy to be prepared, and then drying; the dried blocky beryllium copper residues and electrolytic copper are put into a crucible of a vacuum induction melting furnace, gradient heating melting is carried out in a vacuum state, and molten metal is obtained; the molten metal is heated, refined and fully stirred, then protective gas is inflated into the vacuum induction melting furnace to reach the atmospheric pressure, and after standing is conducted, dross on the surface of the molten metal is removed; and the molten metal with the scum removed from the surface is cast into a mold, demolding is conducted after natural cooling, and the beryllium-copper master alloy is obtained. The beryllium content of the mother alloy for beryllium bronze is high, and the preparation requirement of the high-beryllium beryllium copper alloy can be met.

Description

Technical Field

[0001] This invention belongs to the field of beryllium bronze preparation technology, and particularly relates to a method for preparing a master alloy for beryllium bronze from beryllium copper residue. Background Technology

[0002] Beryllium bronze is a high-performance alloy with copper as the base and small amounts of beryllium, nickel, cobalt, and other elements added. It possesses high strength, excellent electrical conductivity, corrosion resistance, non-magnetic properties, and fatigue resistance, making it suitable for precision engineering and extreme environments. Its high thermal conductivity can shorten mold cooling time, and it is widely used in critical components such as electrical connectors, sensors, brake springs, and explosion-proof tools in the electronics, aerospace, automotive, and petrochemical industries. It is particularly irreplaceable in submarine cables requiring electrical conductivity, wear resistance, or corrosion resistance, making it one of the core materials for high-end manufacturing.

[0003] The production of beryllium bronze requires beryllium copper master alloy as raw material. To obtain high-performance beryllium bronze, the impurity content in the beryllium copper master alloy must be strictly controlled. Currently, to achieve high purity of the beryllium copper master alloy, a filtration casting method is commonly used. With the increase in production cycles, a large amount of filter screen binder and furnace charge are generated, with a beryllium content between 8% and 11%. These materials have high recycling value but are difficult to recycle.

[0004] Currently, there is no established method for recycling high-beryllium copper scrap; it is only used for the preparation of low-beryllium copper alloys. For example, the national patent, application number 202010556844.X, entitled "A Refining and Purification Method for Beryllium Copper Waste," firstly involves drying the beryllium copper alloy scrap, ESR waste, and beryllium copper waste at 180℃~300℃; then, the dried beryllium copper alloy scrap, ESR waste, and beryllium copper waste are sequentially added to a graphite crucible in a vacuum induction furnace, and then melted while being stirred with a gradient heating process to obtain… The molten metal is then refined in a vacuum induction furnace, allowed to stand, and then cast to obtain beryllium copper ingots with a beryllium content of 0.51~0.71wt%. The beryllium content is low and cannot meet the requirements for preparing high-beryllium beryllium copper alloys. However, the iron content is 0.176~0.328wt%, and the content of impurity elements does not meet the current standards. In addition, the graphite flakes or plant ash covering before casting may be drawn into the container during subsequent casting, forming non-metallic inclusions. The slag-forming agent calcium fluoride will volatilize at the refining temperature, causing serious environmental pollution. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a master alloy for beryllium bronze from beryllium copper residue. The master alloy for beryllium bronze prepared by this method has a high beryllium content, which can meet the preparation requirements of high beryllium beryllium copper alloy.

[0006] To achieve the above objectives, the present invention employs the following technical solution: A method for preparing a master alloy for beryllium bronze from beryllium copper residue, the method comprising the following steps: Step S1: After crushing and screening the filter screen adhesive and furnace lining material, particles with an average particle size of 2.5~3.5mm are obtained; Step S2: Press the screened binder and furnace charge particles with a pressure of 60~100MPa for 10~15 minutes to obtain blocky beryllium copper residue; Step S3: Prepare the blocky beryllium copper residue and electrolytic copper according to the desired beryllium copper master alloy and then dry them; Step S4: The dried blocky beryllium copper residue and electrolytic copper are loaded into the crucible of a vacuum induction melting furnace and melted under a gradient heating under vacuum to obtain molten metal. Step S5: Heat the molten metal to 1320~1410℃, refine for 40~100 minutes, stir thoroughly, then fill the vacuum induction melting furnace with protective gas to atmospheric pressure, let stand for 10~20 minutes, and remove the slag from the surface of the molten metal. Step S6: Pour the molten metal after removing the surface slag into the mold, and demold it after natural cooling to obtain the beryllium copper master alloy.

[0007] Furthermore, in step S2, the size of the blocky beryllium copper residue is 15~25mm.

[0008] Further, in step S3, the beryllium content of the beryllium copper master alloy is 3.7~4.3 wt%; In step S3, the drying temperature is 150~250℃ and the time is 6~10 hours.

[0009] Furthermore, in step S4, the vacuum degree of the vacuum state is 3~5 Pa.

[0010] Furthermore, in step S4, the specific process of gradient heating and melting includes: Heat for 30-60 minutes at a heating power of 40-80KW; then heat for 20-30 minutes at a heating power of 100-150KW; and then heat for 30-60 minutes at a heating power of 150-180KW.

[0011] Furthermore, in step S5, the power of the heating is 200~250KW.

[0012] Furthermore, in step S5, the stirring frequency is 50~80Hz.

[0013] Furthermore, in step S6, before casting, the mold is preheated to 200~350°C for 3~6 hours.

[0014] Furthermore, in step S6, the protective gas is high-purity argon or nitrogen.

[0015] In summary, the solution proposed in this invention has the following technical effects: This invention employs vacuum induction melting to achieve efficient recovery of beryllium copper residues with a beryllium content of 8-11 wt%, preparing a beryllium copper master alloy with a beryllium content of 3.7-4.3 wt%. This master alloy can be used as an intermediate alloy to meet the production needs of various high- and low-beryllium bronzes, solving the problem of difficult recovery of filter screen binders and furnace charge generated during the preparation of a 10 wt% beryllium copper master alloy. The beryllium copper master alloy prepared by this invention has low impurity element content, eliminating the need for secondary impurity removal and allowing direct use in the subsequent smelting of beryllium copper products. This invention eliminates the need to add graphite flakes or wood ash before casting, avoiding the formation of non-metallic inclusions in the beryllium copper master alloy. This invention also eliminates the need to add slag-forming agent calcium fluoride, making it environmentally friendly. The beryllium copper master alloy of this embodiment has uniform composition, low metallic impurity content, and few non-metallic inclusions, making it suitable as a master alloy for the production of high- and low-beryllium bronzes. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] This embodiment provides a method for preparing a master alloy for beryllium bronze from beryllium copper scrap, the method comprising the following steps: Step S1: After crushing and screening the filter screen adhesive and furnace lining material, particles with an average particle size of 2.5~3.5mm are obtained.

[0018] Step S2: Press the screened binder and furnace charge particles with a pressure of 60~100MPa for 10~15 minutes to obtain blocky beryllium copper residue.

[0019] To achieve high-density loading and prevent large pieces of material from supporting each other and forming "bridges," this embodiment uses 15-25mm in size for the blocky beryllium copper residue. This shortens the melting time, reduces energy consumption, avoids local overheating or incomplete melting, thereby improving the purity of the melt, reducing porosity and inclusion defects in the ingot, achieving precise chemical composition control, and preventing element segregation or excessive burning.

[0020] Step S3: Prepare the blocky beryllium copper residue and electrolytic copper according to the desired beryllium copper master alloy and then dry them.

[0021] This embodiment controls the drying temperature to 150-250℃ and the drying time to 6-10 hours to remove volatile impurities such as moisture and oil that may be adsorbed on the surface of the raw materials. This effectively prevents these impurities from suddenly vaporizing under the high temperature environment of subsequent vacuum melting, avoiding "boiling over" and splashing of the melt, ensuring operational safety and process stability, and reducing the gas content (especially hydrogen) in the molten metal. This significantly reduces the tendency for porosity to form in the ingot and improves the purity and fluidity of the alloy liquid. In this embodiment, the beryllium copper master alloy has a beryllium content of 3.7-4.3 wt% as an intermediate alloy to meet the production requirements of various high-beryllium and low-beryllium bronzes.

[0022] Step S4: The dried blocky beryllium copper residue and electrolytic copper are loaded into the crucible of a vacuum induction melting furnace and melted under a gradient heating under vacuum to obtain molten metal.

[0023] This embodiment controls the vacuum level at 3~5 Pa to ensure the rapid floating and removal of gaseous impurities in the molten metal, while avoiding the volatilization of beryllium.

[0024] This embodiment effectively removes adsorbed gases and low-melting-point volatiles from the furnace charge and furnace body through gradient heating, avoiding "boiling over" or splashing caused by rapid gas expansion due to rapid heating in the early stages of smelting, thus ensuring a safe and stable smelting process. Simultaneously, slow heating maintains a stable vacuum level within the furnace, creating favorable conditions for subsequent refining. Gradient heating helps ensure that all elements in the alloy, especially easily oxidized beryllium, achieve sufficient and uniform melting and diffusion, reducing component segregation, and ultimately obtaining a high-quality beryllium copper alloy melt with low gas content, uniform composition, and dense microstructure. The specific process of gradient heating melting includes: Heat for 30-60 minutes at a heating power of 40-80KW; then heat for 20-30 minutes at a heating power of 100-150KW; and then heat for 30-60 minutes at a heating power of 150-180KW.

[0025] Step S5: Heat the molten metal to 1320~1410℃, refine for 40~100 minutes, stir thoroughly, then fill the vacuum induction melting furnace with protective gas to atmospheric pressure, let stand for 10~20 minutes, and then remove the slag from the surface of the molten metal.

[0026] This embodiment reduces the viscosity of the solution by raising the molten metal to a high temperature of 1320~1410℃, ensuring refining effect and achieving the removal of gaseous impurities and homogenization of solute elements.

[0027] In this embodiment, the heating power is controlled at 200~250KW and the stirring frequency is controlled at 50~80Hz to ensure uniform temperature field distribution of molten metal, homogenization of alloying elements, and removal of gas inclusions by floating.

[0028] Before casting, a silicon carbide filter screen is placed at the gate to filter out any incomplete internal inclusions.

[0029] Step S6: Pour the molten metal after removing the surface slag into the mold, and demold it after natural cooling to obtain the beryllium copper master alloy.

[0030] In this embodiment, preheating the mold to 200-350°C for 3-6 hours before casting reduces the significant temperature difference between the mold and the molten metal, effectively preventing the solution from instantly solidifying upon contact with the cold mold. This avoids defects such as cold shuts, porosity, or incomplete filling in the casting. Simultaneously, it slows down the alloy's cooling rate, promoting the removal of gases and impurities and ensuring a more uniform solidification process, reducing the risk of thermal stress and cracking caused by uneven shrinkage. Furthermore, preheating improves the fluidity of the molten alloy, ensuring it fills even the smallest parts of the mold cavity, thus enhancing the casting's dimensional accuracy, surface finish, and internal density.

[0031] In this embodiment, the protective gas is high-purity argon or nitrogen.

[0032] The technical solution of the present invention is illustrated below through specific embodiments: Example 1: Step S1: After crushing and screening the filter screen adhesive and furnace lining material, particles with an average particle size of 3.5 mm are obtained.

[0033] Step S2: Press the screened binder and furnace charge particles with a pressure of 60 MPa for 10 minutes to obtain blocky beryllium copper residue with a size of 25 mm.

[0034] Step S3: After preparing the blocky beryllium copper residue and electrolytic copper according to the beryllium copper master alloy to be prepared, dry them at 150°C for 6 hours.

[0035] Step S4: The dried blocky beryllium copper residue and electrolytic copper are loaded into the crucible of the vacuum induction melting furnace. Under a vacuum of 3 Pa, the furnace is heated for 30 minutes with a heating power of 40 KW; then heated for 20 minutes with a heating power of 100 KW; and finally heated for 30 minutes with a heating power of 150 KW to achieve gradient heating and melting, thus obtaining molten metal.

[0036] Step S5: Heat the molten metal to 1320℃ with a heating power of 200KW, refine for 40 minutes, then stir thoroughly with a stirring frequency of 50Hz, and then fill the vacuum induction melting furnace with high-purity nitrogen to atmospheric pressure. After standing for 10 minutes, remove the slag from the surface of the molten metal.

[0037] Step S6: Pour the molten metal after removing the surface slag into the preheated mold, and demold it after natural cooling to obtain the beryllium copper master alloy.

[0038] The total metal yield of the beryllium copper master alloy in this embodiment was 92.4%. The chemical composition analysis results of the beryllium copper master alloy are as follows: Be: 3.70 wt%; Ni: 0.078 wt%; Fe: 0.050 wt%; Al: 0.032 wt%; Si: 0.098 wt%; C: 0.013 wt%; O: 0.0097 wt%; H: 0.0018 wt%.

[0039] Example 2: Step S1: After crushing and screening the filter screen adhesive and furnace lining material, particles with an average particle size of 3.0 mm are obtained.

[0040] Step S2: Press the screened binder and furnace charge particles at 80 MPa for 12 minutes to obtain blocky beryllium copper residue with a size of 15 mm.

[0041] Step S3: After preparing the blocky beryllium copper residue and electrolytic copper according to the beryllium copper master alloy to be prepared, dry them at 200°C for 10 hours.

[0042] Step S4: The dried blocky beryllium copper residue and electrolytic copper are loaded into the crucible of the vacuum induction melting furnace. Under a vacuum of 4 Pa, the furnace is heated for 45 minutes with a heating power of 60 KW; then heated for 25 minutes with a heating power of 120 KW; and finally heated for 45 minutes with a heating power of 165 KW to achieve gradient heating and melting, thus obtaining molten metal.

[0043] Step S5: Heat the molten metal to 1370℃ using a power of 220KW and refine for 70 minutes. Then, stir thoroughly at a stirring frequency of 65Hz. Next, fill the vacuum induction melting furnace with high-purity argon gas to atmospheric pressure. After standing for 15 minutes, remove the slag from the surface of the molten metal. Place a silicon carbide filter screen at the gate to filter out any remaining internal inclusions.

[0044] Step S6: Preheat the mold to 280°C for 3 hours, then pour the molten metal after removing the surface slag into the preheated mold. After natural cooling, demold to obtain beryllium copper master alloy.

[0045] The total metal yield of the beryllium copper master alloy in this embodiment is 95.1%, and the chemical composition analysis results of the beryllium copper master alloy are as follows: Be: 4.3 wt%; Ni: 0.086 wt%; Fe: 0.087 wt%; Al: 0.027 wt%; Si: 0.067 wt%; C: 0.018 wt%; O: 0.0058 wt%; H: 0.0023 wt%.

[0046] Example 3: Step S1: After crushing and screening the filter screen adhesive and furnace lining material, particles with an average particle size of 3.5 mm are obtained.

[0047] Step S2: Press the screened binder and furnace charge particles with a pressure of 100 MPa for 15 minutes to obtain blocky beryllium copper residue with a size of 20 mm.

[0048] Step S3: After preparing the blocky beryllium copper residue and electrolytic copper according to the beryllium copper master alloy to be prepared, dry them at 250°C for 8 hours.

[0049] Step S4: The dried blocky beryllium copper residue and electrolytic copper are loaded into the crucible of the vacuum induction melting furnace. Under a vacuum of 5 Pa, the furnace is heated for 60 minutes with a heating power of 80 KW; then heated for 30 minutes with a heating power of 150 KW; and finally heated for 60 minutes with a heating power of 180 KW to achieve gradient heating and melting, thus obtaining molten metal.

[0050] Step S5: Heat the molten metal to 1410℃ using a power of 250KW and refine for 100 minutes. Then, stir thoroughly at a stirring frequency of 80Hz. Next, fill the vacuum induction melting furnace with high-purity nitrogen to atmospheric pressure. After standing for 20 minutes, remove the slag from the surface of the molten metal. Place a silicon carbide filter screen at the gate to filter out any remaining internal inclusions.

[0051] Step S6: Preheat the mold to 350°C for 6 hours, then pour the molten metal after removing the surface slag into the preheated mold. After natural cooling, demold to obtain a beryllium copper master alloy with a beryllium content of 4.0 wt%.

[0052] The total metal yield of the beryllium copper master alloy in this embodiment was 97.2%. The chemical composition analysis results of the beryllium copper master alloy are as follows: Be: 4.0wt%; Ni: 0.093 wt%; Fe: 0.086 wt%; Al: 0.029 wt%; Si: 0.069 wt%; C: 0.0099 wt%; O: 0.008 wt%; H: 0.0026 wt%.

[0053] Example 4: Step S1: After crushing and screening the filter screen adhesive and furnace lining material, particles with an average particle size of 3.2 mm are obtained.

[0054] Step S2: Press the screened binder and furnace charge particles with a pressure of 70 MPa for 10 minutes to obtain blocky beryllium copper residue with a size of 22 mm.

[0055] Step S3: After preparing the blocky beryllium copper residue and electrolytic copper according to the beryllium copper master alloy to be prepared, dry them at 220°C for 7 hours.

[0056] Step S4: The dried blocky beryllium copper residue and electrolytic copper are loaded into the crucible of the vacuum induction melting furnace. Under a vacuum of 4 Pa, the furnace is heated for 50 minutes with a heating power of 70 KW; then heated for 28 minutes with a heating power of 140 KW; and finally heated for 40 minutes with a heating power of 170 KW to achieve gradient heating and melting, and obtain molten metal.

[0057] Step S5: Heat the molten metal to 1400℃ using a power of 230KW and refine for 70 minutes. Then, stir thoroughly at a stirring frequency of 60Hz. Next, fill the vacuum induction melting furnace with high-purity argon gas to atmospheric pressure. After standing for 18 minutes, remove the slag from the surface of the molten metal. Place a silicon carbide filter screen at the gate to filter out any remaining internal inclusions.

[0058] Step S6: Preheat the mold to 260°C for 5 hours, then pour the molten metal after removing the surface slag into the preheated mold. After natural cooling, demold to obtain beryllium copper master alloy.

[0059] The total metal yield of the beryllium copper master alloy in this embodiment was 96.8%, and the chemical composition analysis results of the beryllium copper master alloy are as follows: Be: 4.1wt%; Ni: 0.090 wt%; Fe: 0.082 wt%; Al: 0.026 wt%; Si: 0.065 wt%; C: 0.0094 wt%; O: 0.007 wt%; H: 0.0022 wt%.

[0060] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method of preparing a master alloy for beryllium bronze from beryllium copper scrap, characterized in that, The method comprises the following steps: Step S1, crushing and screening the filter screen bonding material and the furnace bonding material to obtain particles with an average particle size of 2.5-3.5 mm; Step S2, pressing the screened particles of the bonding material and the furnace bonding material for 10-15 minutes at a pressure of 60-100 MPa to obtain a block-shaped beryllium copper residual material; Step S3, drying the block-shaped beryllium copper residual material and electrolytic copper after preparing the beryllium copper master alloy; Step S4, loading the dried block-shaped beryllium copper residual material and electrolytic copper into a crucible of a vacuum induction melting furnace, and performing gradient temperature rising melting under a vacuum state to obtain a metal liquid; Step S5, heating the metal liquid to 1320-1410°C, refining for 40-100 minutes, and then fully stirring, then filling the vacuum induction melting furnace with a protective gas to atmospheric pressure, standing for 10-20 minutes, and then removing the surface dross of the metal liquid; Step S6, casting the metal liquid after removing the surface dross into a mold, naturally cooling, and then demolding to obtain a beryllium copper master alloy.

2. The method of claim 1, wherein, In the step S2, the size of the block-shaped beryllium copper residual material is 15-25 mm.

3. The method of claim 2, wherein, In the step S3, the beryllium content of the beryllium copper master alloy is 3.7-4.3 wt%; In the step S3, the drying temperature is 150-250°C, and the time is 6-10 hours.

4. The method according to any one of claims 1 to 3, characterized in that, In the step S4, the vacuum degree of the vacuum state is 3-5 Pa.

5. The method of claim 4, wherein, In the step S4, the specific process of the gradient temperature rising melting comprises: After heating for 30-60 minutes at a heating power of 40-80 KW, then heating for 20-30 minutes at a heating power of 100-150 KW, and then heating for 30-60 minutes at a heating power of 150-180 KW.

6. The method of claim 5, wherein, In the step S5, the heating power is 200-250 KW.

7. The method of claim 6, wherein, In the step S5, the stirring frequency is 50-80 Hz.

8. The method of claim 7, wherein, In the step S6, before casting, the mold is preheated to 200-350°C for 3-6 hours.

9. The method of claim 8, wherein, In the step S6, the protective gas is high-purity argon or nitrogen.