Beryllium-copper alloy with low residual stress and excellent bad direction molding and preparation method of beryllium-copper alloy
By employing a dual process of vacuum melting and electroslag remelting, along with subsequent treatments, a beryllium copper alloy with uniform grains and low internal stress was prepared. This solved the problem of residual stress generated during the processing of beryllium copper alloys, meeting the design requirements of advanced connectors and improving stamping stability and assembly accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-10
- Publication Date
- 2026-04-03
AI Technical Summary
Existing beryllium copper alloys generate significant work-hardened layers and microscopic residual tensile stress during processing, resulting in severe material anisotropy. This makes it impossible to meet the design requirements of non-directional bending for tip connectors and affects the dimensional accuracy and service life of stamped parts.
By employing a dual process of vacuum melting and electroslag remelting, combined with high-processing-rate cold rolling, rapid solution treatment, and stress-relief sand washing, and through homogenization annealing and multi-roll straightening, a beryllium copper alloy with uniform grains and low internal stress is prepared, forming a residual compressive stress layer to offset tensile stress and improve the formability in the bad direction.
The microstructure uniformity and plate shape accuracy of beryllium copper alloy were achieved, meeting the design requirements of non-directional bending of tip connectors, improving stamping stability and assembly accuracy, reducing residual stress, and extending fatigue life.
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Figure CN121776291A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of beryllium copper alloy material processing technology, and particularly relates to a beryllium copper alloy with excellent low residual stress and bad-direction forming and its preparation method. Background Technology
[0002] Beryllium copper alloys (typically C17200), as a typical precipitation-strengthened copper alloy, are hailed as the "king of non-ferrous elastic materials" due to their unique combination of properties, achieving tensile strengths exceeding 1000 MPa and electrical conductivity exceeding 22% IACS after solution-aging heat treatment. These superior characteristics of high strength and high conductivity make them irreplaceable in the field of precision stamping, especially in the manufacture of microelectronic components (such as IC lead frames, high-speed connectors, and micro-switch springs) where extremely stringent requirements for dimensional accuracy, mechanical property consistency, and electrical performance are necessary.
[0003] Currently, with the accelerated transformation of global industries towards intelligent and electric power, especially the explosive growth in new energy vehicles, 5G communications, high-end equipment, and aerospace, higher-dimensional performance requirements are being placed on key basic materials. Taking high-voltage connectors for new energy vehicles as an example, their working environment involves high voltage, high current, and frequent vibration, requiring the beryllium copper strip used to simultaneously meet the following requirements: extremely high strength (to resist plastic deformation during insertion and removal), excellent conductivity (to reduce heat accumulation during current transmission), superior stress relaxation resistance (to ensure stable contact pressure under long-term vibration), stringent bending formability (to adapt to complex and compact structural designs; ideally, the relative bending radius R / t in both the good and bad directions should approach 0, achieving "right-angle bending"), and impeccable surface cleanliness. The latter directly relates to the quality of subsequent precious metal plating (such as gold plating and silver plating) and is a prerequisite for ensuring low contact resistance, high corrosion resistance, and long service life of the connector.
[0004] To meet the requirements of "high surface quality," the domestic industry chain has generally upgraded traditional chemical cleaning lines to physical cleaning processes of "mechanical grinding + polishing." However, this technical approach has inherent and serious drawbacks: while the grinding and polishing process removes microscopic unevenness on the surface, it also generates a significant work-hardened layer and microscopic residual tensile stress on the surface of beryllium copper strip due to intense mechanical action, accompanied by a large amount of micron-sized copper powder that is difficult to completely remove. This copper powder is highly susceptible to detachment and intrusion into the gaps of precision molds during subsequent high-speed stamping, not only causing micron-sized pits and scratches on the surface of the stamped parts, becoming a source of stress concentration and reducing fatigue life; but also flowing with the plating solution during the electroplating process, causing increased plating porosity and decreased adhesion, leading to an abnormal surge in the cost of precious metals (gold, silver), and ultimately affecting the conductivity stability and environmental corrosion resistance of the components.
[0005] Currently, the main process used is "cold rolling-solution-aging," which makes it difficult to effectively control the deep-level microstructure uniformity and macroscopic residual stress. While intense cold plastic deformation imparts strength to the material, it also introduces high-density dislocations and significant texture, resulting in pronounced anisotropy. This is particularly evident in the significant difference between the bending performance in the bad direction (perpendicular to the rolling direction) and the good direction (typically R / t value ≥ 2), failing to meet the design requirements of "non-directional" bending for tip connectors. Furthermore, the residual stress within the strip redistributes and is released after stamping, causing dimensional drift and warping deformation in the workpiece, severely affecting assembly accuracy. Summary of the Invention
[0006] One of the objectives of this invention is to provide a method for preparing a beryllium copper alloy with excellent bad-direction forming and low residual stress. This method can produce beryllium copper alloys with uniform grain size, low internal stress, excellent bad-direction forming, high plate shape accuracy and good stamping stability, which can meet the design requirements of "non-directional" bending of tip connectors, while ensuring assembly accuracy.
[0007] The second objective of this invention is to provide a beryllium copper alloy with excellent low residual stress and good orientation forming properties.
[0008] To achieve one of the above objectives, the present invention employs the following technical solution: A method for preparing a beryllium copper alloy with excellent low residual stress and good orientation forming properties, the method comprising the following steps: Step S1: Weigh the beryllium copper master alloy, electrolytic copper, and rare earth elements according to the various components and their mass percentages of the beryllium copper alloy. Step S2: Add beryllium copper master alloy, electrolytic copper and rare earth elements to a vacuum induction furnace for vacuum melting to obtain beryllium copper alloy melt and beryllium copper alloy electroslag smelting slag system; Step S3: Cast the molten beryllium copper alloy into a beryllium copper alloy electrode; Step S4: Slag the beryllium copper alloy electroslag smelting slag system to form a molten slag pool; Step S5: Under argon protection, the beryllium copper alloy electrode is vertically inserted into the molten slag pool for segmented electroslag melting to obtain a beryllium copper alloy ingot. Step S6: The beryllium copper alloy ingot is subjected to homogenization annealing, hot rolling, multi-pass high-processing-rate cold rolling, solution treatment, finished product cold rolling, stress-relieving sand washing, and stress-relieving plate straightening in sequence.
[0009] Further, in step S1, the components of the beryllium copper alloy and their mass percentages include: Be, 1.8~2.1%; Ni+Co, 0.2~0.5%; Fe≤0.05%; Al≤0.05%; Si≤0.05%; rare earth elements, 0.01~0.05wt%; balance is copper and unavoidable impurities; The rare earth element is at least one of Ce, La, Sc and Y.
[0010] Furthermore, in step S2, the specific process of vacuum melting includes: Under a vacuum of 5-15 Pa, the temperature is raised to 1180-1240℃ and stirred for 10-20 min; then the temperature is raised to 1180-1240℃ and stirred for another 10-20 min. The heating and stirring are repeated 1-5 times until the mixture is completely melted, resulting in beryllium copper alloy melt and beryllium copper alloy electroslag smelting slag system.
[0011] Furthermore, in step S5, the segmented electroslag smelting includes a first-stage electroslag smelting and a second-stage electroslag smelting. The voltage of the first stage of electroslag melting is 30-50V, the current is 3000-5000A, the temperature is 1200-1350℃, and the time is 30-50min; The second stage of electroslag melting involves a voltage of 30V to 40V, a current of 1500 to 2000A, a temperature of 1200 to 1300℃, and a time of 10 to 20 minutes.
[0012] Furthermore, in step S6, the specific process of homogenization annealing includes: A. Calculate the homogenization annealing time using the thickness of the beryllium copper alloy ingot according to the following formula: ; in, To homogenize the annealing time; The thickness of the beryllium copper alloy ingot is in mm. The speed is 20~40 mm / min; B. Heat the beryllium copper alloy ingot to 720~800℃ and hold it for the homogenization annealing time.
[0013] Furthermore, in step S6, the hot rolling temperature should be greater than 620°C, the total deformation should be no less than 90%, and the single deformation should be no less than 15%. In step S6, the total processing rate of the high-processing-rate cold rolling is greater than 80%.
[0014] Furthermore, in step S6, the specific process of the solution treatment includes: The beryllium copper alloy ingots after high machining rate cold rolling are solution treated in a vertical solution furnace under nitrogen-hydrogen mixed gas protection, then cooled with high circulation nitrogen-hydrogen mixed gas, and then quenched at a temperature of 720-830℃ for 20s-15min.
[0015] Furthermore, in step S6, the specific process of stress-relief sand washing includes: At a speed of 10–30 m / min and a temperature of 70–100 °C, the beryllium copper alloy strip obtained after solution treatment was sequentially subjected to degreasing, pickling, and sand washing. The degreasing and cleaning time is 4–10 seconds; The pickling temperature is 25–100°C, and the time is 20–60 seconds; The acid solution used for pickling is either H2SO4 or HNO3; The mass concentration of the acid solution used for pickling is 15-25%. The pressure of the sand washing is 0.1–0.5 MPa; The mass ratio of sand to water in the water-sand mixture is 10-25:75-90.
[0016] Furthermore, in step S6, the specific process of stress-relieving plate straightening includes: Using a tension of 5~25KN / mm 2 Diameter is Rollers with a diameter of 8-20mm are used for stretching and straightening, followed by straightening of 5-9 sets of multi-rollers in a straight line.
[0017] To achieve the second objective mentioned above, the present invention employs the following technical solution: A beryllium copper alloy with excellent low residual stress and good orientation forming properties is prepared by the preparation method described above.
[0018] In summary, the solution proposed in this invention has the following technical effects:
[0019] This invention produces high-purity beryllium copper ingots through a dual process of vacuum melting and electroslag remelting. Homogenization treatment eliminates dendritic segregation, and combined with high-rate cold rolling and rapid solution treatment, refines the grain size. A stress-relief sand washing process forms a residual compressive stress layer on the strip surface, and high-tension stretching and multi-roll straightening achieve coordinated control of shape and stress, ensuring the uniformity of the beryllium copper strip's microstructure, reducing residual stress, and improving non-directional formability. The beryllium copper alloy strip of this invention possesses excellent characteristics such as uniform grain size (15~25μm), low internal stress, excellent non-directional formability, high shape accuracy, and good stamping stability. It provides a reliable process path for the efficient and stable production of beryllium copper strip for high-end connectors, meeting the design requirements of "non-directional" bending in cutting-edge connectors while ensuring assembly accuracy. This achieves independent control over key electronic component materials, meeting the urgent need to support the secure development of national strategic emerging industries. Attached Figure Description
[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0021] Figure 1 This is a flowchart of the microstructure of the beryllium copper alloy in Example 1; Figure 2 This is a 100× schematic diagram of the surface of the beryllium copper alloy in Example 1; Figure 3 This is a schematic diagram of a 40× curved surface with a 90° R / T=0 angle in Example 1. Figure 4 This is a flowchart of the microstructure of the beryllium copper alloy in Example 2; Figure 5 This is a 100× schematic diagram of the surface of the beryllium copper alloy in Example 2; Figure 6 This is a schematic diagram of a 40× curved surface with a 90° R / T=0 angle in Example 2. Figure 7 This is a flowchart of the microstructure of the beryllium copper alloy in Example 3; Figure 8 This is a 100× schematic diagram of the surface of the beryllium copper alloy in Example 3; Figure 9 This is a schematic diagram of a 40× curved surface with 90°R / T=0 in Example 3. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.
[0023] This embodiment provides a method for preparing a beryllium copper alloy with excellent low residual stress and good orientation forming properties. The preparation method includes the following steps: Step S1: Weigh out the beryllium copper master alloy, electrolytic copper, and rare earth elements according to the various components and their mass percentages of the beryllium copper alloy.
[0024] This embodiment, based on the traditional beryllium copper alloy, redesigns the Be content and the contents of the main alloying elements Ni and Co. This ensures that the beryllium copper alloy matrix has a suitable proportion of alloying elements, which, after subsequent solid solution and aging strengthening treatments, forms a stable, finely dispersed second phase, improving the strength and toughness of the beryllium copper alloy. The role of each element and the basis for their proportions are as follows: Co and Ni are essential elements for ensuring the alloy's properties. In this invention, they form ordered body-centered cubic compounds NiBe and CoBe with Be during the solid solution process. In this embodiment, Co and Ni hinder grain growth of beryllium copper during heating, delay solid solution decomposition, suppress grain boundary reactions, and avoid microstructural inhomogeneities near grain boundaries due to over-aging, thereby improving the precipitation hardening effect of the beryllium copper alloy.
[0025] Fe: Fe can refine grains, increase plasticity, and inhibit grain boundary reactions during aging. Through the processing technology of this invention, fine, dispersed precipitates such as ferrous intermetallic compounds can be formed, improving the strength of beryllium copper alloys. However, the amount of Fe added will increase the brittleness of the beryllium copper alloy and affect its formability; therefore, its upper limit is specified as 0.05%.
[0026] Cerium (Ce): Cerium is a strong deoxidizer. By adding cerium (Ce), the oxygen content in beryllium copper alloys can be reduced, improving the plasticity and toughness of beryllium copper alloys. It can also refine the grains, improving the strength and corrosion resistance of beryllium copper alloys.
[0027] Lanthanum (La): Lanthanum can be used as a grain refiner to improve the microstructure of beryllium copper alloys, enhance the mechanical properties of the material, and at the same time improve the oxidation resistance and corrosion resistance of beryllium copper alloys.
[0028] Scandium (Sc): Scandium is an effective grain refiner that can significantly improve the strength and toughness of copper alloys, as well as their electrical conductivity and corrosion resistance.
[0029] Yttrium (Y): Yttrium can improve the high-temperature strength and oxidation resistance of copper alloys, making them suitable for high-temperature applications. Yttrium can also improve the processing and welding properties of alloys.
[0030] In summary, the components and their mass percentages of the beryllium copper alloy in this embodiment include: Be, 1.8~2.1%; Ni+Co, 0.2~0.5%; Fe≤0.05%; Al≤0.05%; Si≤0.05%; rare earth elements, 0.01~0.05wt%; balance is copper and unavoidable impurities; The rare earth element is at least one of Ce, La, Sc and Y.
[0031] In this embodiment, the beryllium mass percentage in the beryllium copper master alloy is 4-10%.
[0032] Step S2: Add beryllium copper master alloy, electrolytic copper and rare earth elements to a vacuum induction furnace for vacuum melting to obtain beryllium copper alloy melt and beryllium copper alloy electroslag smelting slag system.
[0033] Vacuum melting with consumable electrodes under a protective atmosphere can effectively remove non-metallic inclusions such as oxides, improve the as-cast solidification structure, and reduce macroscopic segregation. The specific vacuum melting process in this embodiment includes: Under a vacuum of 5-15 Pa, the temperature is raised to 1180-1240℃ and stirred for 10-20 min; then the temperature is raised to 1180-1240℃ and stirred for another 10-20 min. The heating and stirring are repeated 1-5 times until the mixture is completely melted, resulting in beryllium copper alloy melt and beryllium copper alloy electroslag smelting slag system.
[0034] This embodiment uses stirring at speeds 1 to 5.
[0035] Step S3: Cast the molten beryllium copper alloy into a beryllium copper alloy electrode.
[0036] Nitrogen gas is introduced into the flow channel and the insulation bag to a slightly positive pressure of 0.5 ~ 2.0 kPa. The molten alloy is transferred from the furnace through the flow channel into the insulation bag. The molten metal in the insulation bag flows directly into the crystallizer of the casting machine through the gating pipe. The flow is controlled by an automatic stopper rod control mechanism with visual recognition of the liquid level, and the casting process begins to form the beryllium copper alloy electrode.
[0037] Step S4: Slag the beryllium copper alloy electroslag smelting slag system to form a molten slag pool.
[0038] The slag pool plays multiple roles in electroslag remelting. It not only melts the electrodes by generating heat through resistance, but also acts as a filter medium to remove impurities from the metal, while providing thermal insulation to promote controlled solidification.
[0039] Step S5: Under argon protection, the beryllium copper alloy electrode is vertically inserted into the molten slag pool for segmented electroslag melting to obtain a beryllium copper alloy ingot.
[0040] This embodiment combines consumable electrode vacuum melting and electroslag remelting processes to further refine the beryllium copper alloy in a controlled atmosphere, significantly reducing the content of harmful elements such as oxygen and sulfur, thereby comprehensively improving the purity, compositional uniformity and overall performance of the beryllium copper alloy.
[0041] The core of the segmented electroslag remelting process for beryllium copper alloys lies in the precise control of electrical parameters, temperature, and melting time to optimize the molten pool behavior and the final ingot quality. In this embodiment, the segmented electroslag remelting includes a first-stage electroslag remelting and a second-stage electroslag remelting. The first-stage electroslag remelting is the critical period for the electrodes to begin melting and forming the initial molten pool. In this embodiment, the voltage for the first-stage electroslag remelting is 30–50V, the current is 3000–5000A, the temperature is 1200–1350℃, and the time is 30–50 minutes. The high current (3000–5000A) aims to provide sufficient Joule heat (generated by the resistance of the slag layer) to rapidly melt the electrode tip and form molten metal droplets. The temperature is controlled within the range of 1200–1350℃ to ensure sufficient melting of the beryllium copper alloy and good slag pool fluidity. The molten metal droplets pass through the slag layer, undergoing a metallurgical reaction with the slag to remove impurities such as oxygen and phosphorus, and promoting the flotation and separation of non-metallic inclusions. Maintaining this stage for a relatively long time (30-50 minutes) helps stabilize the molten pool and lays the foundation for the subsequent refining process.
[0042] In this embodiment, the second stage of electroslag melting uses a voltage of 30V–40V, a current of 1500–2000A, a temperature of 1200–1300℃, and a time of 10–20 minutes. The significantly reduced current (1500–2000A) in the second stage slows the melting rate, promotes solidification, and further optimizes the microstructure of the ingot. The lower current helps reduce the depth of the molten metal pool, thereby improving the stability of the solidification front and effectively suppressing macroscopic segregation. Maintaining a temperature of 1200–1300℃ remains important in this stage to ensure good fluidity of the slag pool and the molten metal pool, and to continue the refining reaction. The shorter melting time (10–20 minutes) likely indicates that this stage focuses more on controlling the solidification process rather than large-scale metal melting.
[0043] Step S6: The beryllium copper alloy ingot is subjected to homogenization annealing, hot rolling, multi-pass high-processing-rate cold rolling, solution treatment, finished product cold rolling, stress-relieving sand washing, and stress-relieving plate straightening in sequence.
[0044] Dendritic segregation is prone to occur during the casting process of beryllium copper alloys, leading to uneven distribution of elements between dendrites and dendrites, which affects the mechanical and electrical properties of the material. Homogenization annealing, through prolonged holding at high temperature, utilizes the atomic diffusion mechanism to promote the redistribution of solute elements, effectively eliminating microsegregation and making the composition and microstructure more homogeneous, providing good initial microstructure conditions for subsequent processing. The specific process of homogenization annealing in this embodiment includes: A. Calculate the homogenization annealing time using the thickness of the beryllium copper alloy ingot according to the following formula: ; in, To homogenize the annealing time; The thickness of the beryllium copper alloy ingot is in mm. The speed is 20~40 mm / min; B. Heat the beryllium copper alloy ingot to 720~800℃ and hold it for the homogenization annealing time.
[0045] In this embodiment, the hot rolling temperature should be greater than 620°C, the total deformation should be no less than 90%, and the single deformation should be no less than 15%. The total processing rate of the high-processing-rate cold rolling is greater than 80%.
[0046] The specific process of solution treatment in this embodiment includes: The beryllium copper alloy ingots after high machining rate cold rolling are solution treated in a vertical solution furnace under nitrogen-hydrogen mixed gas protection, then cooled with high circulation nitrogen-hydrogen mixed gas, and then quenched at a temperature of 720-830℃ for 20s-15min.
[0047] Beryllium copper strip is prone to residual tensile stress during processing, which reduces fatigue life and increases stress corrosion susceptibility. Sandblasting (i.e., stress-relief sandblasting) can form a residual compressive stress layer on the strip surface. This compressive stress can partially offset the tensile stress generated by external loads, thereby delaying the initiation and propagation of fatigue cracks. As a strengthening process, stress blasting can further optimize stress distribution under prestressed conditions, significantly improving the material's stamping performance. The specific process of stress-relief sandblasting in this embodiment includes: The beryllium copper alloy strip obtained after solution treatment was subjected to degreasing, pickling, and sand washing sequentially at a speed of 10–30 m / min and a temperature of 70–100 °C. The degreasing cleaning time was 4–10 s.
[0048] The pickling temperature is 25–100℃, the pickling time is 20–60 s, and the pickling acid solution is either H2SO4 or HNO3, with a mass concentration of 15–25%. The sand washing pressure is 0.1–0.5 MPa, and the mass ratio of sand to water in the water-sand mixture is 10–25:75–90.
[0049] Beryllium copper strip is prone to uneven residual stress during cold rolling and heat treatment, leading to defects such as warping and deformation during stamping. Tension straightening, by applying a combination of tension and bending deformation, induces plastic flow in high-stress areas, achieving stress redistribution. After removing the load, the internal stress field of the strip becomes more uniform, significantly improving dimensional stability and facilitating subsequent precision stamping. The specific process of stress-relief strip straightening in this embodiment includes: Using a tension of 5~25KN / mm 2 Diameter is Rollers with a diameter of 8-20 mm are used for stretching and straightening, followed by multi-roll straightening with 5-9 sets of rollers in a straight line. Applying combined stretching and bending deformation induces plastic flow in high-stress areas, achieving stress redistribution. After the load is removed, the internal stress field of the strip becomes more uniform, and dimensional stability is significantly improved, which is beneficial for subsequent precision stamping.
[0050] This embodiment utilizes a dual process of vacuum melting and electroslag remelting to prepare high-purity beryllium copper ingots. Homogenization treatment eliminates dendritic segregation, and combined with high-rate cold rolling and rapid solution treatment, refines the grain size. A stress-relief sand washing process forms a residual compressive stress layer on the strip surface, and high-tension stretching and multi-roll straightening achieve coordinated control of shape and stress, ensuring the uniformity of the beryllium copper strip's microstructure, reducing residual stress, and improving non-directional formability. The beryllium copper alloy strip of this embodiment possesses excellent characteristics such as uniform grain size (15~25μm), low internal stress, excellent non-directional formability, high shape accuracy, and good stamping stability. This provides a reliable process path for the efficient and stable production of beryllium copper strip for high-end connectors, meeting the design requirements of "non-directional" bending in cutting-edge connectors while ensuring assembly accuracy. It achieves independent control over key electronic component materials, meeting the urgent need to support the secure development of national strategic emerging industries.
[0051] The technical solution of the present invention is illustrated below with specific embodiments: Example 1: 1. Weigh out a beryllium copper master alloy (8% beryllium by mass), electrolytic copper, and Ce, according to the components and their mass percentages of the beryllium copper alloy. The components and their mass percentages of the beryllium copper alloy include: Be, 2.0%; Ni, 0.2%; Co, 0.1%; Fe, 0.05%; Al, 0.05%; Si, 0.05%; Ce, 0.03t%; balance is copper and unavoidable impurities; 2. Add beryllium copper master alloy, electrolytic copper and rare earth elements into a vacuum induction furnace, evacuate to 10 Pa, heat to 1220℃ until completely melted, stir at speed 1 to 3 for 15 minutes; then heat to 1220℃ again, continue stirring for 15 minutes, repeat the heating and stirring process 3 times until completely melted, to obtain beryllium copper alloy melt and beryllium copper alloy electroslag smelting slag system.
[0052] 3. Fill the flow channel and insulation bag with nitrogen gas to 1.0 kPa. Transfer the molten beryllium copper alloy from the furnace into the insulation bag through the flow channel. The molten beryllium copper alloy in the insulation bag flows directly into the crystallizer of the casting machine through the gating pipe. The flow is controlled by an automatic stopper rod with visual liquid level recognition function, and the casting begins to form the beryllium copper alloy electrode.
[0053] 4. Slag-forming is performed on the electroslag smelting slag system of beryllium copper alloy to form a molten slag pool.
[0054] 5. Under argon protection, the beryllium copper alloy electrode is vertically inserted into the molten slag pool for segmented electroslag melting to obtain a beryllium copper alloy ingot. The first stage of electroslag melting is performed at a voltage of 40V, a current of 4000A, a temperature of 1280℃, and a time of 40 minutes. The second stage of electroslag melting is performed at a voltage of 35V, a current of 1800A, a temperature of 1250℃, and a time of 15 minutes.
[0055] 6. Heat the beryllium copper alloy ingot to 760℃, hold for 240 minutes, and then hot roll at a rolling temperature of 630℃, with a total deformation of 95% and a single deformation of 20%.
[0056] 7. The hot-rolled beryllium copper alloy ingot is cold-rolled with a large processing rate of 84% to obtain beryllium copper alloy strip and foil with a grain size of 15μm. 8. The beryllium copper alloy strip and foil were solution treated in a vertical solution furnace under nitrogen-hydrogen mixed gas protection, then cooled with high-circulation nitrogen-hydrogen mixed gas, and then quenched at 780℃ for 6 minutes.
[0057] 9. Cold-roll the solution-treated beryllium copper alloy strip and foil to a grain size of 20μm. 10. After degreasing and cleaning the 20μm beryllium copper alloy strip and foil material at 85℃ for 8 seconds at a speed of 20m / min, pickle it with 20% H2SO4 at 60℃ for 40 seconds. Then, spray water sand with a sand content of 20% evenly onto the surface of the beryllium copper alloy strip and foil material at a pressure of 0.3MPa.
[0058] 11. Use a tension of 15KN / mm 2 Diameter is The 14mm rollers are used for stretching and straightening, and then for straightening with 7 sets of multi-roller rollers in a straight line.
[0059] The beryllium copper alloy in this embodiment has a grain size of 18 μm, an internal stress of 38~43 MPa, excellent non-directional forming properties, high sheet shape accuracy, and good stamping stability. (Reference) Figure 1 , 2 And 3.
[0060] Example 2: 1. Weigh out a beryllium copper master alloy (10% beryllium by mass), electrolytic copper, and Ce, according to the components and their mass percentages of the beryllium copper alloy. The components and their mass percentages of the beryllium copper alloy include: Be, 2.1%; Ni, 0.3%; Co, 0.2%; Fe, 0.04%; Al, 0.04%; Si, 0.04%; Ce, 0.02%; La, 0.03%; balance: copper and unavoidable impurities. 2. Add beryllium copper master alloy, electrolytic copper and rare earth elements into a vacuum induction furnace, evacuate to 15 Pa, heat to 1240℃ until completely melted, and stir at speed 1 to 5 for 20 minutes; then heat to 1240℃ again and continue stirring for 20 minutes. Repeat the heating and stirring process 5 times until completely melted to obtain beryllium copper alloy melt and beryllium copper alloy electroslag smelting slag system.
[0061] 3. Fill the flow channel and insulation bag with nitrogen gas until a slight positive pressure of 2.0 kPa is reached. Transfer the molten beryllium copper alloy from the furnace through the flow channel into the insulation bag. The molten beryllium copper alloy in the insulation bag flows directly into the crystallizer of the casting machine through the gating pipe. The flow is controlled by an automatic stopper rod with visual liquid level recognition function, and the casting begins to form the beryllium copper alloy electrode.
[0062] 4. Slag-forming is performed on the electroslag smelting slag system of beryllium copper alloy to form a molten slag pool.
[0063] 5. Under argon protection, the beryllium copper alloy electrode is vertically inserted into the molten slag pool for segmented electroslag melting to obtain a beryllium copper alloy ingot. The first stage of electroslag melting is performed at a voltage of 50V, a current of 5000A, a temperature of 1350℃, and a time of 50min. The second stage of electroslag melting is performed at a voltage of 40V, a current of 2000A, a temperature of 1300℃, and a time of 20min.
[0064] 6. Heat the beryllium copper alloy ingot to 800℃, hold for 360 minutes, and then hot roll at a rolling temperature of 650℃ with a total deformation of 92% and a single deformation of 18%.
[0065] 7. The hot-rolled beryllium copper alloy ingot is cold-rolled with a large processing rate of 88% to obtain beryllium copper alloy strip and foil with a grain size of 10μm. 8. The beryllium copper alloy strip and foil are solution treated in a vertical solution furnace under nitrogen-hydrogen mixed gas protection, then cooled with high-circulation nitrogen-hydrogen mixed gas, and then quenched at 830℃ for 20s.
[0066] 9. Cold-roll the solution-treated beryllium copper alloy strip and foil to a grain size of 15μm. 10. After degreasing and cleaning the 15μm beryllium copper alloy strip and foil material at a speed of 30m / min and a temperature of 100℃ for 10s, pickle it with 25% HNO3 at a temperature of 100℃ for 60s. Then, spray water sand with a sand content of 25% evenly onto the surface of the beryllium copper alloy strip and foil material at a pressure of 0.5MPa.
[0067] 11. Use a tension of 25KN / mm 2 Diameter is 8mm rollers are used for stretching and straightening, followed by straightening of 9 sets of multi-roller rollers.
[0068] The beryllium copper alloy in this embodiment has a grain size of 15μm, an internal stress of 35~45MPa, excellent non-directional forming properties, high sheet shape accuracy, and good stamping stability. (Reference) Figure 4 , 5 And 6.
[0069] Example 3: 1. Weigh out a beryllium copper master alloy (4% beryllium by mass), electrolytic copper, and Sc, according to the components and their mass percentages of the beryllium copper alloy. The components and their mass percentages of the beryllium copper alloy include: Be, 1.8%; Ni, 0.1%; Co, 0.1%; Fe, 0.04%; Al, 0.04%; Si, 0.04%; Sc, 0.01%; balance: copper and unavoidable impurities; 2. Add beryllium copper master alloy, electrolytic copper and rare earth elements into a vacuum induction furnace, evacuate to 5 Pa, heat to 1180℃ until completely melted, and stir at speeds 2 and 3 for 10 minutes; then heat to 1180℃ again and continue stirring for 10 minutes. Repeat the heating and stirring process once until completely melted to obtain beryllium copper alloy melt and beryllium copper alloy electroslag smelting slag system.
[0070] 3. Fill the flow channel and insulation bag with nitrogen gas until a slight positive pressure of 0.5 kPa is reached. Transfer the molten beryllium copper alloy from the furnace through the flow channel into the insulation bag. The molten beryllium copper alloy in the insulation bag flows directly into the crystallizer of the casting machine through the gating pipe. The flow is controlled by an automatic stopper rod with visual liquid level recognition function, and the casting begins to form the beryllium copper alloy electrode.
[0071] 4. Slag-forming is performed on the electroslag smelting slag system of beryllium copper alloy to form a molten slag pool.
[0072] 5. Under argon protection, the beryllium copper alloy electrode is vertically inserted into the molten slag pool for segmented electroslag melting to obtain a beryllium copper alloy ingot. The first stage of electroslag melting is performed at a voltage of 30V, a current of 3000A, a temperature of 1200℃, and a time of 30 minutes. The second stage of electroslag melting is performed at a voltage of 30V, a current of 1500A, a temperature of 1200℃, and a time of 10 minutes.
[0073] 6. Heat the beryllium copper alloy ingot to 720℃, hold for 120 minutes, and then hot roll at a rolling temperature of 640℃, with a total deformation of 90% and a single deformation of 15%.
[0074] 7. The hot-rolled beryllium copper alloy ingot is cold-rolled with a large processing rate of 82% to obtain beryllium copper alloy strip and foil with a grain size of 20μm. 8. The beryllium copper alloy strip and foil are solution treated in a vertical solution furnace under nitrogen-hydrogen mixed gas protection, then cooled with high-circulation nitrogen-hydrogen mixed gas, and then quenched at 720℃ for 15 minutes.
[0075] 9. Cold-roll the solution-treated beryllium copper alloy strip and foil to a grain size of 25μm. 10. After degreasing and cleaning the 15μm beryllium copper alloy strip and foil material at a speed of 10m / min and a temperature of 70℃ for 4s, pickle it with 15% HNO3 at a temperature of 25℃ for 20s. Then, spray water sand with a sand content of 10% evenly onto the surface of the beryllium copper alloy strip and foil material at a pressure of 0.1MPa.
[0076] 11. Use a tension of 5KN / mm 2 Diameter is The 20mm rollers are used for stretching and straightening, and then for straightening with five sets of multi-rollers in a straight line.
[0077] The beryllium copper alloy in this embodiment has a grain size of 25 μm, an internal stress of 36~40 MPa, excellent non-directional forming properties, high sheet shape accuracy, and good stamping stability. (Reference) Figure 7 , 8 And 9.
[0078] 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 for preparing a beryllium copper alloy with excellent low residual stress and poor orientation forming properties, characterized in that, The preparation method includes the following steps: Step S1: Weigh the beryllium copper master alloy, electrolytic copper, and rare earth elements according to the various components and their mass percentages of the beryllium copper alloy. Step S2: Add beryllium copper master alloy, electrolytic copper and rare earth elements to a vacuum induction furnace for vacuum melting to obtain beryllium copper alloy melt and beryllium copper alloy electroslag smelting slag system; Step S3: Cast the molten beryllium copper alloy into a beryllium copper alloy electrode; Step S4: Slag the beryllium copper alloy electroslag smelting slag system to form a molten slag pool; Step S5: Under argon protection, the beryllium copper alloy electrode is vertically inserted into the molten slag pool for segmented electroslag melting to obtain a beryllium copper alloy ingot. Step S6: The beryllium copper alloy ingot is subjected to homogenization annealing, hot rolling, multi-pass high-processing-rate cold rolling, solution treatment, finished product cold rolling, stress-relieving sand washing, and stress-relieving plate straightening in sequence.
2. The preparation method according to claim 1, characterized in that, In step S1, the components of the beryllium copper alloy and their mass percentages include: Be, 1.8~2.1%; Ni+Co, 0.2~0.5%; Fe≤0.05%; Al≤0.05%; Si≤0.05%; rare earth elements, 0.01~0.05%; balance is copper and unavoidable impurities; The rare earth element is at least one of Ce, La, Sc and Y.
3. The preparation method according to claim 2, characterized in that, In step S2, the specific process of vacuum melting includes: Under a vacuum of 5-15 Pa, the temperature is raised to 1180-1240℃ and stirred for 10-20 min; then the temperature is raised to 1180-1240℃ and stirred for another 10-20 min. The heating and stirring are repeated 1-5 times until the mixture is completely melted, resulting in beryllium copper alloy melt and beryllium copper alloy electroslag smelting slag system.
4. The preparation method according to any one of claims 1 to 3, characterized in that, In step S5, the segmented electroslag smelting includes a first-stage electroslag smelting and a second-stage electroslag smelting. The voltage of the first stage of electroslag melting is 30-50V, the current is 3000-5000A, the temperature is 1200-1350℃, and the time is 30-50min; The second stage of electroslag melting involves a voltage of 30V to 40V, a current of 1500 to 2000A, a temperature of 1200 to 1300℃, and a time of 10 to 20 minutes.
5. The preparation method according to claim 4, characterized in that, In step S6, the specific process of homogenization annealing includes: A. Calculate the homogenization annealing time using the thickness of the beryllium copper alloy ingot according to the following formula: ； in, To homogenize the annealing time; The thickness of the beryllium copper alloy ingot is in mm. The speed is 20~40 mm / min; B. Heat the beryllium copper alloy ingot to 720~800℃ and hold it for the homogenization annealing time.
6. The preparation method according to claim 5, characterized in that, In step S6, the rolling temperature of the hot rolling should be greater than 620°C, the total deformation should be not less than 90%, and the single deformation should be not less than 15%. In step S6, the total processing rate of the high-processing-rate cold rolling is greater than 80%.
7. The preparation method according to claim 6, characterized in that, In step S6, the specific process of the solution treatment includes: The beryllium copper alloy ingots after high machining rate cold rolling are solution treated in a vertical solution furnace under nitrogen-hydrogen mixed gas protection, then cooled with high circulation nitrogen-hydrogen mixed gas, and then quenched at a temperature of 720-830℃ for 20s-15min.
8. The preparation method according to claim 7, characterized in that, In step S6, the specific process of stress-relief sand washing includes: At a speed of 10–30 m / min and a temperature of 70–100 °C, the beryllium copper alloy strip obtained after solution treatment was sequentially subjected to degreasing, pickling, and sand washing. The degreasing and cleaning time is 4–10 seconds; The pickling temperature is 25–100°C, and the time is 20–60 seconds; The acid solution used for pickling is either H2SO4 or HNO3; The mass concentration of the acid solution used for pickling is 15-25%. The pressure of the sand washing is 0.1–0.5 MPa; The mass ratio of sand to water in the water-sand mixture is 10-25:75-90.
9. The preparation method according to claim 8, characterized in that, In step S6, the specific process of stress-relieving plate straightening includes: Using a tension of 5~25KN / mm 2 Diameter is Rollers with a diameter of 8-20mm are used for stretching and straightening, followed by straightening of 5-9 sets of multi-rollers in a straight line.
10. A beryllium copper alloy with excellent low residual stress and good orientation forming properties, characterized in that, The low residual stress, non-directional forming excellent beryllium copper alloy is prepared by the preparation method described in any one of claims 1 to 9.