A copper alloy formula with ultra-low resistivity and low temperature drift coefficient and a processing technology thereof

Abstract

The application provides a copper alloy formula with ultralow resistivity and low temperature coefficient of resistance and a processing technology, and belongs to the technical field of alloy materials.The copper alloy formula provided by the application has the following weight percentages: Mn: 5.0%-6.0%; X (one or more of aluminum group elements): 1.0%-4.0%, and the balance of Cu and other inevitable trace components. In the selection of X (aluminum group elements), the mixed multiple elements are more conducive to the realization of resistivity and TCR. The alloy resistivity is 0.20-0.25 mu Omega*m, and the average temperature drift coefficient TCR in the range of 20-125 DEG C is 30-60 ppm / DEG C. The processing technology includes the following steps: component collocation, smelting and casting, multiple annealing, three-way forging, rough rolling and finish rolling. Through reasonable component collocation and processing technology, the alloy of the application can simultaneously have ultralow resistivity and low temperature drift coefficient, and meet the demand of the resistance and shunt industry.

Description

Technical Field

[0001] This invention belongs to the field of alloy materials technology, and more specifically, it relates to a copper alloy formula and processing technology with ultra-low resistivity and low temperature drift coefficient. Background Technology

[0002] Currently, in the resistor and shunt industry, due to the optimization of terminal design schemes, the demand for resistors and shunts is trending towards lower resistivity and lower temperature drift coefficients. In resistor and shunt design, the terminal has specific size requirements. Therefore, given that the dimensions of resistors and shunts cannot be adjusted, these problems can only be solved by obtaining metals with lower resistivity and lower temperature drift coefficients. Currently, the main low-resistivity copper alloy formulations applicable to resistors and shunts include:

[0003] 1. CnMn7Sn, grade 6J607, belongs to the copper-based precision alloy family. Its composition is 6.5%–7.5% manganese, 2.0%–3.0% tin, with copper as the balance. Its key characteristic is a resistivity of 0.29 Nm³ / s. The temperature drift coefficient is ±10. ;

[0004] 2. CuMn3 grade MC012 belongs to the category of heating alloys. Its formula is 3% manganese and the balance copper. Specifically, it exhibits a resistivity of 0.15. Temperature drift coefficient less than 300 ;

[0005] The temperature drift coefficient of 1 is excellent, but the resistivity is 0.29. It no longer meets market demand; the resistivity of 2 is excellent, but the temperature drift coefficient is too large, which does not meet market demand at all.

[0006] The alloys produced by the above formula cannot maintain a certain level of temperature drift coefficient while allowing the resistivity to continue to decrease. For example, the CnMn7Sn alloy mentioned above, although with a temperature drift coefficient of ±10... However, its resistivity is 0.29. The temperature drift coefficient of CuMn3 can only reach <300. However, the resistivity can be reduced to an even lower 0.15. For the surface mount resistor industry, the required resistive metal must simultaneously meet the requirement of a resistivity of less than 0.29. TCR below 50 The requirements are not met, but neither of the two commonly used metals mentioned above can satisfy them. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a copper alloy formulation and processing technology with ultra-low resistivity and low-temperature drift coefficient, thereby solving the technical problem that traditional alloys in the prior art cannot simultaneously achieve ultra-low resistivity and low-temperature drift coefficient.

[0008] The purpose and effectiveness of this invention—a copper alloy formulation and processing technology with ultra-low resistivity and low-temperature drift coefficient—are achieved by the following specific technical means:

[0009] A copper alloy formulation with ultra-low resistivity and low temperature drift coefficient, wherein the weight percentage of each component is as follows:

[0010] Mn: 5.0%~6.0%;

[0011] X: 1.0%~4.0%;

[0012] The balance is Cu and other unavoidable components;

[0013] Wherein, X is any one or more elements in the Al group.

[0014] Preferably, the resistivity of the copper alloy is 0.20 to 0.25. .

[0015] Preferably, the copper alloy is 20-125. The average temperature drift coefficient (TCR) is 30–60. .

[0016] A processing technology for copper alloys with ultra-low resistivity and low temperature drift coefficient includes the following steps:

[0017] S1: Based on a copper alloy formula with ultra-low resistivity and low temperature drift coefficient, the components are matched to obtain a mixed raw material;

[0018] S2: Melt the mixed raw materials to obtain molten material, and cast the molten material to obtain ingots;

[0019] S3: Anneal the ingot to obtain an annealed billet;

[0020] S4: Perform at least two cycles of processing on the annealed billet. Each cycle includes triaxial multi-directional forging and gradient annealing to obtain annealed sheet material.

[0021] S5: The annealed sheet is rough rolled using a rough rolling mill to obtain a rough rolled billet;

[0022] S6: Anneal the rough-rolled billet to obtain the cold-rolled billet;

[0023] S7: Cold-rolled billets are precision rolled using a finishing mill to obtain precision-rolled plates;

[0024] S8: Anneal the precision-rolled sheet to obtain the finished sheet.

[0025] Preferably, the melting in S2 is vacuum melting or melting under inert atmosphere protection.

[0026] Preferably, the annealing temperature in S3 is greater than 700°C. The heat preservation time shall not be less than 4 hours, and the cooling rate shall not be less than 45%. And it is carried out under a reducing atmosphere.

[0027] Preferably, the annealing temperature in S5 is 350–550°C. The heat preservation time is 2 to 6 hours, and the cooling rate is not less than 45%. And it is carried out under a reducing atmosphere;

[0028] The annealing temperature in S6 is 350–550 °C. The heat preservation time is 2 to 6 hours, and the cooling rate is not less than 45%. And it is carried out under a reducing atmosphere;

[0029] The annealing temperature for S8 is 350–550 °C. The heat preservation time is 2 to 6 hours, and the cooling rate is not less than 45%. And it is carried out under a reducing atmosphere.

[0030] Preferably, the thickness of the plate after rough rolling in S5 is no more than 2mm.

[0031] Preferably, in S7, the cold-rolled billet needs to be precision rolled to a specified thickness.

[0032] Preferably, the S8 annealing treatment can also be replaced by continuous line heat treatment at a temperature of 350-600°C and a holding time of 5-15 minutes, and carried out in a reducing atmosphere.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The formulation of this invention mainly relies on multiple alloying elements to increase the mixing entropy of the alloy, increase the lattice disorder, reduce phonon scattering, solid solution of non-magnetic elements of the aluminum group in the Cu-Mn lattice, increase the interatomic spacing of Mn, destroy the correlation between spin magnetic moments, SP orbital hybridization, and suppress spin magnetic moments.

[0035] By employing the above principles, the resistance change dominated by thermal vibration caused by temperature variations is suppressed, achieving a TCR (temperature resistance coefficient) close to 0 in this alloy material. Low resistivity is achieved by maximizing the copper content based on the aforementioned principles, thus reducing resistivity. The final alloy resistivity is 0.20–0.25. , in the range of 20 to 125 The average TCR is 30–60. . Attached Figure Description

[0036] Figure 1 This is a table showing the test results of the copper alloy composition and performance of various embodiments and comparative examples of the present invention;

[0037] Figure 2 This is a schematic diagram of the processing flow for an ultra-low resistivity, low-temperature drift coefficient copper alloy.

[0038] Figure 3 This is a schematic diagram of the copper alloy grain size of the present invention. Figure 1 ;

[0039] Figure 4 This is a schematic diagram of the copper alloy grain size of the present invention. Figure 2 . Detailed Implementation

[0040] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the technical solutions of the present invention, but should not be used to limit the scope of protection of the present invention.

[0041] Example:

[0042] The technical solution of the present invention will be further described in a non-limiting manner below with reference to several preferred embodiments.

[0043] Example 1:

[0044] A copper alloy with ultra-low resistivity and low temperature drift coefficient, wherein the weight percentages of each component are as follows:

[0045] Mn: 5.0%~6.0%;

[0046] X: 1.0%~4.0%;

[0047] The balance is Cu and other unavoidable components;

[0048] Wherein, X is any one or more elements in the Al group.

[0049] like Figure 1 The performance test data shown indicates that this embodiment uses a copper matrix co-doped with Al, In, and Ga aluminum group elements, prepared using the processing technology described in this invention. The resistivity of this alloy can be stably controlled between 0.20 and 0.25. 20-125 The average temperature coefficient of change (TCR) within the range is 30–60. It can achieve a synergistic adaptation of ultra-low resistivity and low temperature drift performance, meeting the core performance requirements of precision resistors and shunts.

[0050] In summary, based on the above formula test results, a higher manganese content results in higher resistivity and lower TCR; a higher total amount of aluminum group elements also results in higher resistivity and lower TCR. Based on the above verification cases, if low resistivity and low TCR are preferred, the optimal experimental groups are groups 6 and 7; if the lowest resistivity is preferred and TCR is secondary, then group 6 is the preferred option; if TCR is the primary consideration, then group 7 is preferred.

[0051] Furthermore, such as Figure 2 , Figure 3 As shown, this embodiment provides a processing technology for copper alloys with ultra-low resistivity and low temperature drift coefficient, including the following steps:

[0052] S1: Based on a copper alloy formula with ultra-low resistivity and low temperature drift coefficient, the components are matched to obtain a mixed raw material.

[0053] It is understood that the components must be weighed strictly in accordance with the weight percentage range specified in this invention. After weighing, mechanical mixing is used to ensure that each component is fully homogeneous, so as to ensure that there is no component segregation in the mixed raw materials, providing a stable raw material basis for subsequent smelting processes, and avoiding batch-to-batch fluctuations in the final alloy properties due to uneven mixing of raw materials.

[0054] S2: Melt the mixed raw materials to obtain molten material, and cast the molten material to obtain ingots;

[0055] S2 is smelting in a vacuum or inert atmosphere.

[0056] Vacuum melting or inert atmosphere-protected melting can isolate oxygen in the air, prevent copper and alloying elements from oxidizing and burning off during high-temperature melting, reduce the formation of oxide inclusions, and ensure the purity and composition accuracy of the molten material. The casting process adopts bottom pouring or tilting casting methods, which can reduce air entrapment and slag inclusions, and obtain a dense ingot.

[0057] S3: Anneal the ingot to obtain an annealed billet;

[0058] The annealing temperature in S3 is greater than 700°C. The heat preservation time shall not be less than 4 hours, and the cooling rate shall not be less than 45%. And it is carried out under a reducing atmosphere;

[0059] Understandably, this annealing is a high-temperature diffusion annealing, at temperatures above 700°C. The temperature should be maintained at a level not lower than 45°C for at least 4 hours to promote the full diffusion of alloying elements within the ingot and eliminate dendritic segregation and compositional inhomogeneity generated during the casting process; The cooling rate can suppress abnormal grain growth during annealing; the reducing atmosphere can prevent the ingot surface from oxidizing at high temperatures, ensuring the surface quality of the billet after annealing.

[0060] S4: Perform at least two cycles of processing on the annealed billet. Each cycle includes triaxial forging and gradient annealing to obtain annealed sheet.

[0061] Understandably, by employing a composite cycle of at least two rounds of three-dimensional and multi-dimensional forging combined with gradient annealing, the billet can undergo full plastic deformation in multiple directions, effectively breaking up coarse grains in the as-cast state and refining the alloy matrix structure. At the same time, it allows trace elements added in small amounts to fully diffuse and uniformly disperse, thoroughly improving the problem of component segregation within the alloy. The combination of multiple rounds of deformation and gradient annealing can precisely control the metal recrystallization process, ensuring uniform and consistent alloy metal crystal size, significantly improving the overall density and microstructure uniformity of the sheet, eliminating structural defects caused by casting and single-processing, and simultaneously optimizing the mechanical properties of the sheet, providing high-quality billets with excellent microstructure and properties for subsequent rolling processes.

[0062] S5: The annealed sheet is rough rolled using a rough rolling mill to obtain a rough rolled billet;

[0063] The thickness of the plate after rough rolling in S5 is no more than 2mm.

[0064] Understandably, the main purpose of the rough rolling process is to reduce the thickness of the annealed sheet to a thickness suitable for finishing rolling. After rough rolling, the sheet thickness is no more than 2mm, which can match the processing capacity of the subsequent finishing mill, reduce the rolling load of the finishing rolling process, and ensure the stability of the finishing rolling process and the dimensional accuracy of the finished sheet.

[0065] S6: Anneal the rough-rolled billet to obtain the cold-rolled billet;

[0066] The annealing temperature in S6 is 350–550 °C. The heat preservation time is 2 to 6 hours, and the cooling rate is not less than 45%. And it is carried out under a reducing atmosphere.

[0067] Understandably, this annealing is an intermediate annealing after rough rolling, which can eliminate work hardening and residual stress generated during rough rolling, refine the rolling structure, restore the plasticity of the billet, provide cold-rolled billets with good processing performance for subsequent finishing rolling processes, and ensure that the finishing rolling process can proceed smoothly.

[0068] S7: Cold-rolled billets are precision rolled using a finishing mill to obtain precision-rolled plates;

[0069] In S7, the cold-rolled billet needs to be precision rolled to a specified thickness.

[0070] Understandably, the finishing rolling process is a key process for obtaining the final dimensions and surface quality of the finished sheet. It is necessary to strictly control the rolling reduction and rolling speed to finish rolling the cold-rolled billet to the specified thickness determined according to the actual application requirements, so as to ensure that the thickness tolerance, flatness and surface roughness of the finished sheet meet the requirements.

[0071] S8: Anneal the precision-rolled sheet to obtain the finished sheet.

[0072] The annealing temperature for S8 is 350–550 °C. The heat preservation time is 2 to 6 hours, and the cooling rate is not less than 45%. And it is carried out under a reducing atmosphere.

[0073] Understandably, this annealing is the final product annealing, which can eliminate residual stress generated during the finishing rolling process, stabilize the microstructure of the alloy, and ensure that the core electrical performance indicators such as resistivity and temperature drift coefficient of the finished plate meet the requirements and remain stable for a long time; the reducing atmosphere and rapid cooling conditions can further optimize the surface quality and internal structure of the finished plate.

[0074] The S8 annealing process can also be replaced by continuous line heat treatment at a temperature of 350–600°C and a holding time of 5–15 minutes, and carried out in a reducing atmosphere.

[0075] Understandably, using continuous line heat treatment instead of conventional box annealing can achieve continuous production of copper alloy plates, shorten the heat treatment cycle, improve production efficiency, and reduce production costs. The heat treatment temperature of 350-600℃ and the holding time of 5-15 minutes can achieve the same heat treatment effect as conventional annealing, ensuring the consistency of the performance of the finished plates.

[0076] The foregoing has shown and described the basic principles and main features of the present invention and its advantages. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments.

Claims

1. A copper alloy formulation with ultra-low resistivity and low temperature drift coefficient, characterized in that, The weight percentage of each component is as follows: Mn: 5.0%~6.0%; X:1.0%～4.0%; The balance consists of Cu and other unavoidable trace elements; Among them, the X group aluminum elements.

2. The copper alloy formulation with ultra-low resistivity and low temperature drift coefficient according to claim 1, characterized in that: The resistivity of the copper alloy is 0.20–0.

25. .

3. The copper alloy formulation with ultra-low resistivity and low temperature drift coefficient according to claim 1, characterized in that: The copper alloy 20-125 The average temperature drift coefficient (TCR) is 30–60. .

4. A processing technology for copper alloys with ultra-low resistivity and low temperature drift coefficient, characterized in that, Includes the following steps: S1: Based on the copper alloy formula with ultra-low resistivity and low temperature drift coefficient according to any one of claims 1 to 3, the components are matched to obtain mixed raw materials; S2: Melt the mixed raw materials to obtain molten material, and cast the molten material to obtain ingots; S3: Anneal the ingot to obtain an annealed billet; S4: Perform at least two cycles of processing on the annealed billet. Each cycle includes triaxial multi-directional forging and gradient annealing to obtain annealed sheet material. S5: The annealed sheet is rough rolled using a rough rolling mill to obtain a rough rolled billet; S6: Anneal the rough-rolled billet to obtain the cold-rolled billet; S7: Cold-rolled billets are precision rolled using a finishing mill to obtain precision-rolled plates; S8: Anneal the precision-rolled sheet to obtain the finished sheet.

5. The processing technology for ultra-low resistivity and low temperature drift coefficient copper alloys according to claim 4, characterized in that: S2 is smelting in a vacuum or inert atmosphere.

6. The processing technology for ultra-low resistivity and low temperature drift coefficient copper alloys according to claim 4, characterized in that: The annealing temperature in S3 is greater than 700°C. The heat preservation time shall not be less than 4 hours, and the cooling rate shall not be less than 45%. And it is carried out under a reducing atmosphere.

7. The processing technology for ultra-low resistivity and low temperature drift coefficient copper alloys according to claim 4, characterized in that: The annealing temperature in S5 is 350–550 °C. The heat preservation time is 2 to 6 hours, and the cooling rate is not less than 45%. And it is carried out under a reducing atmosphere; The annealing temperature in S6 is 350–550 °C. The heat preservation time is 2 to 6 hours, and the cooling rate is not less than 45%. And it is carried out under a reducing atmosphere; The annealing temperature for S8 is 350–550 °C. The heat preservation time is 2 to 6 hours, and the cooling rate is not less than 45%. And it is carried out under a reducing atmosphere.

8. The processing technology for ultra-low resistivity and low temperature drift coefficient copper alloys according to claim 4, characterized in that: The thickness of the plate after rough rolling in S5 is no more than 2mm.

9. The processing technology for ultra-low resistivity and low temperature drift coefficient copper alloys according to claim 4, characterized in that: In S7, the cold-rolled billet needs to be precision rolled to a specified thickness.

10. The processing technology for ultra-low resistivity and low temperature drift coefficient copper alloys according to claim 4, characterized in that: The S8 annealing process can also be replaced by continuous line heat treatment at a temperature of 350–600°C and a holding time of 5–15 minutes, and carried out in a reducing atmosphere.

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