Manganese-copper alloy wire-shaped material for precision resistor and method for manufacturing the same

Abstract

The present application relates to alloy processing technical field, specifically to a kind of manganese-copper alloy linear material for precision resistance and its preparation method, comprising the following steps: according to proportion, raw material is guided to be down continuous casting to obtain casting rod, casting rod is sequentially subjected to first processing, solid solution quenching, cryogenic treatment, second processing to obtain linear semi-finished product, subsequent annealing is obtained manganese-copper alloy linear material for precision resistance;Wherein raw material includes the following mass percentage components Mn 11-13%, Ni 2-5%, the balance is Cu;Down continuous casting includes: first raw material is mixed uniformly, then vacuum smelting is carried out to obtain melt, melt is made to enter the crystallizer of down continuous casting equipment after rod is guided to obtain casting rod;Cryogenic treatment is immersed in liquid nitrogen and treated.The manganese-copper alloy wire processed by the method of the present application has a lower temperature coefficient of resistance at room temperature, and the temperature drift is relatively stable as temperature increases, and can work stably at high temperature.

Description

Technical Field

[0001] This invention relates to the field of alloy processing technology, and more specifically to manganese-copper alloy wire materials for precision resistors and their preparation methods. Background Technology

[0002] Manganese-copper alloy is a resistance alloy material used in standard resistors, shunts, or high-grade metering meters. The processed manganese-copper alloy needs to meet the characteristics of extremely low temperature coefficient of resistance, low thermoelectric potential to copper, and good long-term resistance stability, making it the preferred choice for precision resistors. In recent years, with the rapid development of electronics and electrical appliances, the requirements for current detection have become increasingly precise, posing new challenges to the composition, microstructure uniformity, and machinability of manganese-copper materials.

[0003] Traditional alloy preparation techniques, such as casting and powder metallurgy, all have some shortcomings:

[0004] 1. Vacuum melting + casting: The fluidity of materials with different compositions varies greatly, which places extremely high demands on the design of metal molds. Subsequent hot rolling + hot extrusion processes can easily mix impurities such as oxide scale into the material, affecting the alloy properties, especially the temperature coefficient of resistance of manganese-copper alloys at high temperatures.

[0005] 2. Non-vacuum melting + casting: Mn is relatively reactive and easily burns in air, making it difficult to control the composition content. The composition of each batch of material is inconsistent, and a large amount of material is wasted when making blanks after casting. Moreover, the poor consistency of alloy composition will have an adverse effect on the temperature coefficient of resistance of manganese copper alloy.

[0006] 3. Powder metallurgy: It is costly. First, it requires a powder preparation process. Second, processes such as static pressing and heat treatment are time-consuming. Furthermore, it is difficult to guarantee the density of the prepared materials.

[0007] The above solutions involve complex overall processes and numerous pieces of equipment, making it difficult to guarantee stable and uniform performance across batches, which is not conducive to continuous production for enterprises.

[0008] As the precision level of electronic equipment increases, the precision of the materials used becomes increasingly stringent. For shunts, the resistance temperature coefficient of manganese-copper alloy materials needs to be stable and low. Products manufactured using traditional processes can no longer meet the requirements of new equipment, and there is an urgent need to improve the production process and enhance the performance stability of the materials. Summary of the Invention

[0009] To obtain a manganese-copper alloy material with a stable and low temperature coefficient of resistance, this invention provides a manganese-copper alloy wire material for precision resistors and a method for preparing the same. The manganese-copper alloy wire processed by the method of this invention has a unique microstructure, a low temperature coefficient of resistance at room temperature, and relatively stable temperature drift with increasing temperature.

[0010] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0011] A method for preparing manganese-copper alloy wire material for precision resistors includes the following steps:

[0012] According to the proportion, the raw materials are continuously cast to obtain a casting rod. The casting rod is then subjected to a first processing, solution quenching, cryogenic treatment, and a second processing to obtain a wire-shaped semi-finished product. Subsequent annealing yields a manganese-copper alloy wire material for precision resistors.

[0013] The raw materials mentioned above comprise the following mass percentage components: Mn 11-13%, Ni 2-5%, and the balance being Cu;

[0014] The aforementioned downward continuous casting includes: first, mixing the raw materials evenly and then performing vacuum melting to obtain a molten liquid, then allowing the molten liquid to enter the crystallizer of the downward continuous casting and then drawing the rod to obtain a casting rod;

[0015] Both the first processing and the second processing are deformation processing along the length direction;

[0016] The cryogenic treatment mentioned above is an immersion treatment in liquid nitrogen.

[0017] Further, the raw materials are intermediate alloys and / or elemental metals; preferably, the elemental metals include electrolytic manganese, electrolytic nickel, and oxygen-free copper, wherein the purity of the elemental metals in the electrolytic manganese and electrolytic nickel is greater than 99.9%, and the purity of the elemental copper in the oxygen-free copper is ≥99.95% and the oxygen content is ≤0.002%, such as oxygen-free copper with the grade TU2.

[0018] Further, the vacuum melting includes: mixing the raw materials evenly and placing them in a lower furnace; evacuating the environment inside the lower furnace to 0.1 Pa and then stopping the evacuation; then introducing protective gas until the internal and external gas pressures of the lower furnace are balanced; then heating to 1250±20℃ and holding at that temperature for 5-10 minutes to melt the raw materials into a molten liquid; and then mechanically stirring the molten liquid for 10-20 minutes.

[0019] Preferably, the vacuum melting process employs a stepped heating procedure, holding the temperature for 5-10 minutes after each 100-150°C increase; before the vacuuming, the process further includes heating the temperature inside the lower furnace to 200°C and holding it for 3-10 minutes to dry the raw materials; the protective gas is argon and / or nitrogen.

[0020] Furthermore, the first processing and the second processing respectively include one or more combinations of drawing, rolling, and equal channel corner extrusion; the appropriate processing speed is selected according to the initial diameter of the cast rod. In the first processing: the drawing speed is 5-30 m / min, the rolling speed is 5-50 m / min, and the equal channel corner extrusion speed is 2-10 m / min; the processing speed of the second processing is 800-1000 m / min, processing to the diameter required by the finished product.

[0021] Furthermore, the solution quenching involves holding the variable-diameter material after the first processing at a solution temperature of 850-950℃ for 2-5 hours, followed by water quenching.

[0022] Furthermore, the cryogenic treatment involves immersing the sample in liquid nitrogen for 5-12 minutes.

[0023] Furthermore, the annealing involves vacuum annealing the linear semi-finished product at 350-450°C for 2-5 hours in one or more combinations of helium, argon, and hydrogen atmospheres.

[0024] In another aspect, the present invention provides a manganese-copper alloy wire material for precision resistors, specifically obtained by the above-described preparation method.

[0025] Beneficial technical effects:

[0026] This invention first vacuum melts raw materials such as copper and manganese, then uses downward continuous casting to obtain a cast rod. The microstructure of this cast rod contains regularly arranged elongated columnar crystals. Compared with equiaxed crystals obtained by other casting processes (such as upward continuous casting and horizontal continuous casting), these regularly arranged elongated columnar crystals have the advantages of fewer grain boundaries along the grain direction, lower resistivity, and better uniformity of resistivity distribution along the longitudinal direction, providing initial conditions for obtaining a low temperature coefficient of resistance. In addition, downward continuous casting allows for the design of the cast rod shape. Besides round cast rods, square, trapezoidal, and even irregularly shaped cast rods can be obtained, producing initial products of different shapes for different application scenarios. This reduces the overall processing steps and minimizes material loss during post-processing, which is beneficial for production.

[0027] The casting rod with regularly arranged long columnar crystals is then processed along its length for the first time. The purpose is to obtain a size and shape close to the finished product, while elongating the columnar grains of the casting rod and making the columnar crystals evenly distributed, ensuring the consistency of its internal metallographic structure, which is beneficial to the stability of the temperature coefficient of resistance.

[0028] After the first processing along the length direction, alloying elements will inevitably precipitate within the microstructure. This is caused by the heat of deformation during processing. For second-phase strengthened manganese-copper alloys, the heat of deformation during processing is more significant. A large amount of precipitated alloying elements will reduce the overall uniformity of the manganese-copper alloy material, which is not conducive to the stability of the product's temperature coefficient of resistance. Therefore, after the first processing, solid solution treatment is required to reintegrate the alloying elements into the microstructure. Water quenching is then used to prevent the alloying elements from precipitating again and to restore the uniformity of the composition so that the product's temperature coefficient of resistance is low and stable.

[0029] The dimensions of the product after the first processing are not the dimensions of the final product. Therefore, a second processing along the length is required. However, the second processing will inevitably lead to the precipitation of alloying elements due to deformation heat. To prevent this problem from recurring, cryogenic treatment is first used before deformation processing to achieve the dimensions of the final product. This ensures that the alloying elements are basically retained within the microstructure. On the one hand, cryogenic treatment can suppress deformation heat, ensuring that the temperature is insufficient for alloying elements to precipitate during material processing, thus preventing changes in the microstructure and ensuring a stable temperature coefficient of resistance for the manganese-copper alloy. On the other hand, the deformation twins generated by the deformation after cryogenic treatment have higher thermal stability and can operate stably at higher temperatures.

[0030] After cryogenic deformation (cryogenic treatment and secondary processing), the internal stress of the material is relatively large. If annealing is not performed, the internal stress will be released during subsequent use, resulting in product deformation and ultimately having an adverse effect on the overall resistance. Therefore, subsequent annealing is to release the aforementioned internal stress to ensure that the product does not deform.

[0031] The steps in this invention are closely related and inseparable. The waste rate of this invention is basically zero. The resulting manganese-copper alloy wire material has good consistency in temperature coefficient of resistance and temperature drift. It has a lower temperature coefficient of resistance at room temperature and its temperature drift is relatively stable as the temperature increases, so it can work stably at high temperatures. Attached Figure Description

[0032] Figure 1 This is a process diagram of the method for preparing the manganese-copper alloy with low temperature coefficient of resistance according to the present invention.

[0033] Figure 2 The image shows the metallographic structure of the manganese-copper alloy rod obtained by continuous casting in Example 1, magnified 500 times; the elongated regions are elongated columnar crystals.

[0034] Figure 3 The image shows the metallographic structure of the manganese-copper alloy linear material finally obtained in Example 1, magnified 4000 times; the structure still retains the morphology of long columnar crystals, about 2 μm wide;

[0035] Figure 4 The graph shows the temperature coefficient of resistance of the manganese-copper alloy wire material finally obtained in Example 1 as a function of temperature. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] Unless otherwise specifically stated, the numerical values ​​set forth in these embodiments do not limit the scope of the invention. Techniques and methods known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques and methods should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0038] Furthermore, it should be noted that the use of terms such as "first" and "second" to define the processing steps is merely for the purpose of distinguishing the processing steps. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0039] Experimental methods not specifically described in the following examples are generally determined according to national standards; if no corresponding national standard exists, they are performed according to generally accepted international standards or the standards proposed by relevant enterprises. Unless otherwise stated, all parts are parts by weight, and all percentages are weight percentages.

[0040] Example 1

[0041] The preparation method of manganese-copper alloy wire material for precision resistors, the process is as follows: Figure 1 As shown, the process includes the following steps: the raw materials are continuously cast according to the proportion to obtain a cast rod, and the cast rod is subjected to the first processing, solution quenching, deep cryogenic treatment, and second processing to obtain a wire-shaped semi-finished product. Subsequent annealing yields a manganese-copper alloy wire material for use in precision resistors.

[0042] The specific steps are as follows:

[0043] S1 Ingredients: The raw material proportions are as follows: 8.6 kg of TU00 grade oxygen-free copper, 1.2 kg of electrolytic manganese plate, and 0.2 kg of electrolytic nickel powder;

[0044] S2 Lower Drawing Continuous Casting:

[0045] 1) Adding materials: Use copper foil to wrap Ni powder and evenly distribute Cu, Mn and Ni components;

[0046] 2) Start the furnace: Connect the power supply, place a Φ30mm stainless steel ignition rod in the crystallizer of the lower furnace, turn on the internal circulating cooling water, and control the cooling water temperature at 20±1℃.

[0047] 3) Oven drying: Keep the furnace opening open, raise the furnace body to 200℃ and hold at this temperature for 5 minutes to evaporate the water vapor on the surface of the raw materials;

[0048] 4) Propagate protective gas: Close the furnace cover and heating system, evacuate to 0.1 Pa and then stop evacuating, then introduce argon gas to balance the internal and external gas pressure of the lower furnace;

[0049] 5) Melting: Turn on the heating system, hold for 5 minutes every 150°C increase until it reaches 1250°C, then hold for 10 minutes. After the raw materials in the furnace are completely melted, turn on the mechanical stirring for 10 minutes to obtain a uniform melt.

[0050] 6) Obtaining the casting rod by lower drawing: Start the external circulation cooling water to allow the molten liquid to enter the crystallizer of the lower drawing furnace for rod drawing. The external circulation cooling water will cool the casting rod obtained after passing through the crystallizer for a second time until the rod drawing is completed and a Φ30mm casting rod is obtained.

[0051] The radial microstructure diagram of the cast rod obtained in this step is as follows. Figure 2 As shown, by Figure 2 A distinct columnar crystal structure is visible;

[0052] S3 First processing along the length direction: Roll the Φ30mm cast rod at a rolling speed of 5m / min until it is deformed into a Φ8mm rod;

[0053] S4 Solution quenching: The Φ8mm rod is placed in a heat treatment furnace and held at a solution temperature of 900℃ for 2 hours under argon protection, and then water-cooled for quenching.

[0054] S5 cryogenic treatment: Immerse the Φ8mm rod, which has undergone solution quenching, in liquid nitrogen for 10 minutes;

[0055] S6 undergoes a second processing along its length: after being immersed in liquid nitrogen, it is drawn into wire at a speed of 850 m / min to obtain a Φ1 mm wire;

[0056] S7 Annealing: Place the Φ1mm wire in an annealing furnace, evacuate it, and anneal it at 400°C for 2 hours in a hydrogen atmosphere; then wind and package it to obtain the finished product, a manganese-copper alloy flat wire material for precision resistors.

[0057] The metallographic diagram of the final product in this embodiment is as follows: Figure 3 As shown, by Figure 3 It can be seen that the structure still retains the morphology of long columnar crystals, which are about 2 μm wide.

[0058] Example 2

[0059] The preparation method of manganese-copper alloy wire material for precision resistors, the process is as follows: Figure 1 As shown, the process includes the following steps: the raw materials are continuously cast according to the proportion to obtain a cast rod, and the cast rod is subjected to the first processing, solution quenching, deep cryogenic treatment, and second processing to obtain a wire-shaped semi-finished product. Subsequent annealing yields a manganese-copper alloy wire material for use in precision resistors.

[0060] The specific steps are as follows:

[0061] S1 Ingredients: The raw materials consist of 4 kg of CuMn alloy, 1 kg of CuNi alloy, and 5 kg of TU00 oxygen-free copper; wherein the CuMn alloy contains 30 wt% Mn and the balance is Cu, and the CuNi alloy contains 20 wt% Ni and the balance is Cu.

[0062] S2 Lower Drawing Continuous Casting:

[0063] 1) Adding materials: Wrap the two intermediate alloys mentioned above separately with copper foil, and place the Cu, the wrapped CuMn alloy, and the wrapped CuNi alloy evenly.

[0064] 2) Start the furnace: Connect the power supply, place a Φ30mm stainless steel ignition rod in the crystallizer of the lower furnace, turn on the internal circulating cooling water, and control the cooling water temperature at 20±1℃.

[0065] 3) Oven drying: Keep the furnace opening open, raise the furnace body to 200℃ and hold at this temperature for 5 minutes to evaporate the water vapor on the surface of the raw materials;

[0066] 4) Propagate protective gas: Close the furnace cover and heating system, evacuate to 0.1 Pa and then stop evacuating, then introduce argon gas to balance the internal and external gas pressure of the lower furnace;

[0067] 5) Melting: Turn on the heating system, hold for 10 minutes for every 100°C increase until it reaches 1270°C, then hold for 5 minutes. After the raw materials in the furnace are completely melted, turn on the mechanical stirring for 15 minutes to obtain a uniform melt.

[0068] 6) Obtaining the casting rod by lower drawing: Start the external circulation cooling water to allow the molten liquid to enter the crystallizer of the lower drawing furnace for rod drawing. The external circulation cooling water will cool the casting rod obtained after passing through the crystallizer for a second time until the rod drawing is completed and a Φ30mm casting rod is obtained.

[0069] S3 First processing along the length direction: The Φ30mm cast rod is pulled at a speed of 10m / min until it is deformed to a Φ8mm rod.

[0070] S4 Solution quenching: The Φ8mm rod is placed in a heat treatment furnace and held at a solution temperature of 850℃ for 5 hours under nitrogen protection, and then water-cooled for quenching.

[0071] S5 cryogenic treatment: Immerse the Φ8mm rod, which has undergone solution quenching, in liquid nitrogen for 12 minutes;

[0072] S6 undergoes a second processing along its length: after being immersed in liquid nitrogen, it is drawn into wire at a speed of 800 m / min to obtain a Φ1 mm wire;

[0073] S7 Annealing: Place the Φ1mm wire in an annealing furnace, evacuate it, and anneal it at 350°C for 5 hours in a hydrogen atmosphere; then wind and package it to obtain the finished product, a manganese-copper alloy flat wire material for precision resistors.

[0074] Example 3

[0075] The preparation method of manganese-copper alloy wire material for precision resistors, the process is as follows: Figure 1 As shown, the process includes the following steps: the raw materials are continuously cast according to the proportion to obtain a cast rod, and the cast rod is subjected to the first processing, solution quenching, deep cryogenic treatment, and second processing to obtain a wire-shaped semi-finished product. Subsequent annealing yields a manganese-copper alloy wire material for use in precision resistors.

[0076] The specific steps are as follows:

[0077] S1 Ingredients: The raw material ratio is as follows: 8.5 kg of TU2 grade oxygen-free copper, 1.1 kg of electrolytic manganese plate, and 0.4 kg of electrolytic nickel powder;

[0078] S2 Lower Drawing Continuous Casting:

[0079] 1) Adding materials: Use copper foil to wrap Ni powder, and evenly place Cu, Mn, and the wrapped Ni powder;

[0080] 2) Start the furnace: Connect the power supply, place a Φ30mm stainless steel ignition rod in the crystallizer of the lower furnace, turn on the internal circulating cooling water, and control the cooling water temperature at 20±1℃.

[0081] 3) Oven drying: Keep the furnace opening open, raise the furnace body to 200℃ and hold at this temperature for 5 minutes to evaporate the water vapor on the surface of the raw materials;

[0082] 4) Propagate protective gas: Close the furnace cover and heating system, evacuate to 0.1 Pa and then stop evacuating, then introduce argon gas to balance the internal and external gas pressure of the lower furnace;

[0083] 5) Heating / holding: Turn on the heating system, hold for 8 minutes every 130°C increase until it reaches 1230°C, then hold for 10 minutes. After the raw materials in the furnace are completely melted, turn on the mechanical stirring for 20 minutes to obtain a uniform melt.

[0084] 6) Obtaining the casting rod by lower drawing: Start the external circulation cooling water to allow the molten liquid to enter the crystallizer of the lower drawing furnace for rod drawing. The external circulation cooling water will cool the casting rod obtained after passing through the crystallizer for a second time until the rod drawing is completed and a Φ30mm casting rod is obtained.

[0085] S3 First processing along the length direction: The Φ30mm cast rod is subjected to equal channel angular extrusion at a speed of 20m / min, and deformed into a Φ8mm rod.

[0086] S4 Solution quenching: The Φ8mm rod is placed in a heat treatment furnace and held at a solution temperature of 950℃ for 2 hours under argon protection, and then water-cooled for quenching.

[0087] S5 cryogenic treatment: Immerse the Φ8mm rod, which has undergone solution quenching, in liquid nitrogen for 6 minutes;

[0088] S6 undergoes a second processing along its length: after being immersed in liquid nitrogen, it is drawn into wire at a speed of 900 m / min to obtain a Φ1 mm wire;

[0089] S7 Annealing: The Φ1mm wire is placed in an annealing furnace, and after being evacuated, it is annealed at 450°C for 2 hours in a hydrogen atmosphere; after winding and packaging, the finished product, a manganese copper alloy flat wire material for precision resistors, is obtained.

[0090] Comparative Example 1

[0091] The preparation process of this comparative example is the same as that of Example 1, except that there is no S5 cryogenic treatment. After solution quenching, the second processing is carried out directly, followed by annealing.

[0092] Comparative Example 2

[0093] The preparation process of this comparative example is the same as that of Example 1, except that S2 is horizontal continuous casting: the continuous casting process parameters remain unchanged, the molten alloy liquid is horizontally guided, after one processing, it is solution quenched, then deep cryogenic treatment is performed, and then a second processing is carried out, and finally the finished product is annealed.

[0094] The resistivity of the manganese-copper alloy flat wire material in the above embodiments is 43±3μΩ·cm. The temperature coefficient of resistance of the manganese-copper alloy flat wire material in the above embodiments and comparative examples was determined. The determination method or reference standard GB / T6148 "Test Method for Temperature Coefficient of Resistance of Precision Resistance Alloys" is used. The specific temperature coefficients of resistance at room temperature (25℃), 80℃, and 120℃ are shown in Table 1.

[0095] Table 1. Temperature coefficient of resistance of the examples and comparative products at different temperatures.

[0096]

[0097] As shown in Table 1, the flat wire product of this invention, as a manganese-copper alloy material for precision resistors, exhibits a low temperature coefficient of resistance (TCR) of less than 25 ppm / K at both room and high temperatures. Furthermore, the TCR changes little with increasing temperature, showing good consistency and relatively stable temperature drift. Comparative Example 1, without cryogenic treatment, directly underwent a second processing step after continuous casting, first machining, and solution quenching. The resulting manganese-copper alloy wire after annealing had a higher TCR at both room and high temperatures compared to Example 1. Comparative Example 2, using horizontal continuous casting, produced a manganese-copper alloy wire with an even higher TCR at room temperature, more than twice that of the product in Example 1. Moreover, the TCR decreased significantly at high temperatures, exhibiting poor consistency.

[0098] In another example, the temperature coefficient of resistance of the manganese-copper alloy flat wire material in Example 1 varies with temperature, as shown in the graph below. Figure 4 As shown, by Figure 4 It can be seen that the manganese-copper alloy wire prepared according to the scheme described in Example 1 has a low temperature coefficient of resistance in the range of 25-130℃, a stable rate of change, no obvious temperature drift, and good consistency. It can meet the ±20ppm temperature coefficient of resistance required by precision equipment at the operating temperature.

[0099] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing manganese-copper alloy wire material for precision resistors, characterized in that, Includes the following steps: According to the proportion, the raw materials are continuously cast to obtain a casting rod. The casting rod is then subjected to a first processing, solution quenching, cryogenic treatment, and a second processing to obtain a wire-shaped semi-finished product. Subsequent annealing yields a manganese-copper alloy wire material for precision resistors. The raw materials mentioned herein comprise the following mass percentage components: Mn 11-13%, Ni 2-5%, and the balance being Cu; The aforementioned downward continuous casting includes: first, mixing the raw materials evenly and then performing vacuum melting to obtain a molten liquid; then, allowing the molten liquid to enter the crystallizer of the downward continuous casting equipment and performing a rod extraction to obtain a cast rod; the vacuum melting includes: mixing the raw materials evenly and placing them in a downward furnace; evacuating the environment inside the downward furnace to 0.1 Pa and then stopping the vacuum extraction; then, introducing protective gas until the internal and external gas pressures of the downward furnace are balanced; then, raising the temperature to 1250±20℃ and holding it for 5-10 minutes to melt the raw materials into a molten liquid; and then mechanically stirring the molten liquid for 10-20 minutes. Both the first processing and the second processing are deformation processing along the length direction; The solution quenching process involves holding the variable-diameter material after the first processing at a solution temperature of 850-950℃ for 2-5 hours, followed by water quenching. The cryogenic treatment involves immersing the patient in liquid nitrogen for 5-12 minutes. The annealing process involves vacuum annealing the linear semi-finished product at 350-450°C for 2-5 hours in one or more atmospheres of helium, argon, or hydrogen.

2. The method for preparing manganese-copper alloy wire material for precision resistors according to claim 1, characterized in that, The raw materials are intermediate alloys and / or elemental metals.

3. The method for preparing manganese-copper alloy wire material for precision resistors according to claim 2, characterized in that, The metallic elements include electrolytic manganese, electrolytic nickel, and oxygen-free copper. The purity of the metallic elements in the electrolytic manganese and electrolytic nickel is greater than 99.9%, and the purity of the copper in the oxygen-free copper is ≥99.95%, and the oxygen content is ≤0.002%.

4. The method for preparing manganese-copper alloy wire material for precision resistors according to claim 1, characterized in that, The vacuum melting process employs a stepped heating procedure, holding the temperature for 5-10 minutes for every 100-150°C increase; before the vacuuming, the process also includes heating the temperature inside the lower furnace to 200°C and holding it for 3-10 minutes to dry the raw materials; the protective gas is argon and / or nitrogen.

5. The method for preparing manganese-copper alloy wire material for precision resistors according to claim 1, characterized in that, The first processing and the second processing respectively include one or more combinations of drawing, rolling, and equal channel corner extrusion; In the first processing stage: the drawing speed is 5-30 m / min, the rolling speed is 5-50 m / min, and the equal channel corner extrusion speed is 2-10 m / min; the second processing stage has a processing speed of 800-1000 m / min, and is processed to the diameter required by the finished product.

6. A manganese-copper alloy wire material for precision resistors, characterized in that, The manganese-copper alloy wire material is obtained by the preparation method according to any one of claims 1-5.

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