A method for preparing high-performance CuMnNi alloy by a two-step process

Abstract

The present invention discloses a method for preparing a high-performance CuMnNi alloy by a two-stage process, comprising the following steps: S1. Vacuum induction melting of CuMn 12 Preparation of Ni3 precision resistance alloy ingots, S1-1. Batching, S1-2. Charging the furnace, S1-3. Evacuating, S1-4. Melting, S1-5. Pouring, S1-6. Discharging the furnace, S2. Electroslag remelting of CuMn 12 Preparation of Ni3 precision resistance alloy ingots, S2-1. Selection of slag materials, S2-2. Drying, S2-3. Slag formation, S2-4. Electroslag remelting; By adopting the two-stage process technology of vacuum induction melting plus electroslag remelting, the present invention prepares CuMn 12 Ni3 alloy, which can well eliminate impurities and sulfides existing in the ingots, has a dense structure, uniform composition, and no defects such as shrinkage cavities, gas holes, inclusions, macro and micro segregation, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of non-ferrous metal alloys, and particularly to a method for preparing a high-performance CuMnNi alloy by a two-stage process. Background Art

[0002] As a precision resistance material, copper-manganese alloy is a basic material for making resistance elements in electronic instruments, measuring instruments and other industrial devices. As a resistance alloy material, it has the characteristics of small resistance, low resistance temperature coefficient, low thermoelectric potential to copper, high stability of resistance and relatively high resistivity, and can be made into powders, wires, foils, sheets, tapes, rods, tubes and other shapes. It is mainly used for making standard resistors, shunts, precision or ordinary resistance elements, high-grade measurement voltage, current, bridge, potentiometer and other precision resistance elements of instruments and meters, and is more suitable for making resistance elements of standard resistors for reference.

[0003] At present, the quality of precision resistance alloys produced in China is relatively low, the production capacity is small, and the resistance temperature coefficient is relatively large, which cannot meet the needs of the domestic high-end market. This has prompted scientific research workers in various countries to continuously carry out numerous research works to explore a reasonable process for high-performance CuMn12Ni3 precision resistance alloy to meet the needs of the continuous development of new technologies.

[0004] Since the Germans developed manganin alloy, scientific research workers have continuously explored and developed a series of copper-manganese alloys through continuous exploration and research, including alloy systems such as Cu-Mn-Ni, Cu-Mn-Si, Cu-Mn-Al, and Cu-Mn-Sn. Among them, the most widely used is the Cu-Mn-Ni alloy system. The Cu-Mn-Ni system has an extremely low resistance temperature coefficient and a thermal electromotive force rate to copper, and is easy to deform and process, and has good welding performance. It is one of the ideal materials for shunt resistors.

[0005] At present, high-end manganese copper alloys in the domestic market are all imported. The domestic production process mostly uses non-vacuum melting. The alloy materials produced have high impurity content, uneven composition and structure, and the sulfide impurities in the materials are relatively high, which seriously affect the processing performance and finished product performance of the materials. The performance of various precision instrument elastic elements made is worse than that of foreign countries. In view of the deficiencies existing in the prior art, the present invention provides a method for preparing a CuMn 12 Ni3 precision resistance alloy by using a two-stage process of vacuum induction melting and electroslag remelting, which can well eliminate the impurities and sulfides existing in the ingot, and has a dense structure, uniform composition, and no defects such as shrinkage cavities, pores, inclusions, macro and micro segregation. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a method for preparing a high-performance CuMnNi alloy by a two-stage process.

[0007] The technical solution of the present invention is: a method for preparing a high-performance CuMnNi alloy by a two-stage process, comprising the following steps:

[0008] S1. Vacuum induction melting of CuMn 12 Preparation of Ni3 precision resistance alloy ingot

[0009] S1-1. Batching

[0010] Weigh 11.5-12.5% of electrolytic manganese flakes, 2.7-3.2% of nickel plates and 84.5-85.8% of electrolytic copper plates by mass percentage, and mix them to obtain an alloy material;

[0011] S1-2. Charging the furnace

[0012] Put the alloy material obtained in S1-1 into the crucible furnace, close the furnace lid, close the air release valve, and clean the observation window; among them, a crucible without carbon is selected, because carbon will affect the melting of manganese elements;

[0013] S1-3. Vacuum pumping

[0014] Start the mechanical pump, open the low-vacuum baffle valve to pump vacuum, and start the Roots pump when the vacuum pressure in the crucible furnace ≤ -0.08 MPa;

[0015] S1-4. Melting

[0016] When the vacuum degree ≤ 10 Pa, heat up, and when the alloy material in the crucible furnace starts to melt, reduce the power to below 20 KW, open the argon filling valve, and fill the furnace body with argon with a purity ≥ 99.9% (wt) at a filling rate of 4-6 L / min until the pressure in the crucible furnace rises to -0.08 Mpa, then close the argon filling valve, and then adjust the power to 60 KW and keep melting for 10-15 min;

[0017] S1-5. Pouring

[0018] Adjust the power to 45-55 KW, keep it for 60 s and then pour;

[0019] S1-6. Taking out of the furnace

[0020] Stop heating, cool for 30 min and then take out of the furnace to obtain a CuMn 12 Ni3 vacuum ingot, and process it for standby;

[0021] S2. Electroslag remelting of CuMn 12 Preparation of Ni3 precision resistance alloy ingot

[0022] S2-1. Selection of slag material

[0023] Select a binary slag system with 70 - 80% CaF2 and 20 - 30% Na3AlF6. Weigh 6 - 10 parts of CaO, 30 - 35 parts of Al2O3, 50 - 60 parts of CaF2, and 3 - 5 parts of SiO2 by weight as raw materials;

[0024] S2 - 2, drying

[0025] Place the raw materials weighed in step S2 - 1 in the furnace for drying. Drying temperature: 850 - 950 °C, drying time: 2 - 4 h;

[0026] S2 - 3, slag making

[0027] First, add CaF2 to the slag pool inside the mold and then start arc smelting. Then, add Al2O3, SiO2, and CaO in sequence for slag making to obtain an electroslag remelting slag that can remove sulfur;

[0028] S2 - 4, electroslag remelting

[0029] For the CuMn 12 Ni3 vacuum - cast ingot self - consumable electrode is pre - heated at 200 - 250 °C for 20 - 30 min, then welded to the dummy electrode on the top of the slag pool, and the melting parameters are adjusted for electroslag remelting and feeding. The molten metal solution after feeding flows through the slag pool to the bottom of the mold, cools at the bottom of the mold for 20 - 30 min, and then is demolded and air - cooled to obtain a vacuum electroslag remelting CuMn 12 Ni3 ingot.

[0030] Furthermore, in S1 - 4, the heating and temperature - rising method is: the power is increased to 28 - 32 KW, held for 5 min, the power is increased to 43 - 47 KW, held for 5 min, and the power is increased to 63 - 67 KW and maintained;

[0031] Note: The purpose of the heating and temperature - rising method with a power gradient increase is to make the smelted materials heat evenly and slowly, dry the water vapor and oil stains in the materials, and avoid the influence of water vapor and oil stains on the materials. On the other hand, the power gradient increase is beneficial to protecting the equipment. An instant excessive power will damage the equipment life, and a too - small power will affect the production efficiency.

[0032] Furthermore, in S1 - 5, the casting method is: water - cooled copper - mold casting, casting time: 80 - 100 s;

[0033] Description: The advantage of copper mold casting with water cooling is that the mold has a high cooling intensity, and the ingots produced have fine grain structure and no shrinkage cavities. The specific operation steps are as follows: directly pour the melted and refined copper alloy solution in the crucible into the cavity of the water-cooled copper mold, and take out the ingot in the cavity after the metal solution is completely solidified and cooled. Pouring time less than 80 s is not conducive to the crystallization of the casting structure and the escape of impurities and gases. Pouring time more than 100 s is prone to forming cold shuts, discontinuous structures and other defects. Whether the pouring time is too high or too low, casting defects are likely to be formed.

[0034] Further, in S1-6, the method of the treatment includes the following steps:

[0035] 1) Select ingots that meet the sulfur content requirements

[0036] First, measure the sulfur content of the CuMn 12 Ni3 vacuum ingot obtained in step S1-6, select a vacuum melting CuMn 12 Ni3 ingot with a sulfur content between 100 and 200 ppm, and grind it to a diameter of 100-150 mm as a consumable electrode;

[0037] 2) Surface treatment

[0038] Use a shot blasting machine to grind the inclusions and oxides on the surface of the consumable electrode until the surface is bright, clean, without cracks, shrinkage cavities, gas holes and inclusions;

[0039] 3) Oil stain treatment

[0040] Immerse the consumable electrode after surface treatment in the treatment solution for 2-3 min, then put the ultrasonic cleaner into the treatment solution to clean for 5-10 min, then take it out and put it into a container filled with distilled water to clean for 5-10 min. After taking it out, dry and blow the surface with nitrogen until it is clean and ready for use;

[0041] Note: The diameter of the consumable electrode is matched according to parameters such as the size, depth, mold, and current of the electroslag furnace bath. When the electrode diameter is small, the surface of the electrode receives more radiant heat from the slag surface, and due to the skin effect, the current density on the surface of the electrode is very large, which is not conducive to normal production. The upper limit of the electrode diameter is restricted by the safe gap with the mold wall, and the gap between the two must be greater than the minimum safe distance. When the distance between the electrode and the inner wall of the mold is too small, the proportion of the bypass current flowing into the mold wall from the side of the slag pool increases, resulting in an increase in the heat loss of the slag pool and an increase in power consumption;

[0042] The sulfur content of the vacuum-melted ingot is between 100 and 200 ppm, which can be purified by electroslag smelting to obtain an ingot with a sulfur content of 1 to 3 ppm. A small amount of sulfur can react with manganese to form manganese sulfide with a high melting point, which can eliminate the harmful effects of sulfur to a certain extent, thereby effectively reducing the sulfur content and other impurity elements in the ingot and improving the performance of the material; using nitrogen to blow dry the surface of the vacuum-melted ingot can improve the corrosion resistance of the ingot.

[0043] Furthermore, the treatment solution comprises, by mass percentage, 5-10% anhydrous sodium silicate, 12-15% fatty acid methyl ester ethoxylate sodium sulfonate, 5-10% phosphate ester salt, 12-15% potassium hydroxide and the balance water.

[0044] Note: The treatment solution using the above mass concentration of components can effectively remove oil stains on the vacuum-melted ingots. At the same time, the added anhydrous sodium silicate can inhibit the corrosion of the ingot surface, avoid ingot oxidation, and further improve the alloy properties.

[0045] Further, in S2-1, the slag system may also be any one of binary slag CaF2 70-85%, MgF2 15-30% or binary slag CaF2 70-80%, NaF 20-30% or ternary slag CaF2 60-80%, MgF2 15-30%, CaO 2-10% or rare earth ternary slag CaF2 46-54%, Al2O3 16-24%, CeO 26-34% or pentacyclic slag CaF2 58-62%, CaO8-12%, Al2O3 8-12%, SiO2 8-12%, MgO 8-12%;

[0046] Note: The slag system in the above quality range is the optimal process parameter explored based on production practice, which is more conducive to the casting of alloys and can effectively remove sulfides and other impurities in the material.

[0047] Further, in S2-3, the slag making parameters are: slag making time: 25-30 min, slag making voltage: 45-50 V, slag making current: 500 A-3500 A;

[0048] Note: Slag making time, voltage and current parameters are the optimal process parameters explored based on production practice. Under these process parameters, ingots with consistent composition, good surface quality, and less impurities and other inclusions can be obtained. Slag making time, voltage and current that are too high or too low will affect the quality and production efficiency of the ingot.

[0049] Furthermore, in S2, the desulfurizable electroslag remelting slag and the CuMn 12 The mass ratio of Ni3 vacuum casting consumable electrode is 1:30-50;

[0050] Note: Under the premise of ensuring the stability of the electroslag process, if the mass ratio is too large, that is, the slag volume is too much, the slag pool thickness increases, the slag pool heating density decreases, the melting rate decreases, and the power consumption increases. If the mass ratio is too small, that is, the slag volume is low, it is easy to cause unsatisfactory desulfurization and deslagging effects of the remelted ingot.

[0051] Furthermore, in S2-4, the adjusted smelting parameters are voltage: 53-58V, current: 4000-6000A;

[0052] Note: The magnitude of current and voltage directly affects the melting speed of the electrode and the depth of the metal molten pool. If the current and voltage are too large, the slag temperature will be too high, and the elements will be severely oxidized, which is not conducive to the control of surface quality. If the current and voltage are too small, the melting of the electrode will be affected, and the production efficiency will be reduced.

[0053] Furthermore, in S2-4, the method of compensating shrinkage is: adjusting the starting current to 4000-6000A, and decreasing the current by 500-550A every 3-5 minutes until the current decreases to zero;

[0054] Note: The starting current range is explored based on practical production. By using decreasing power compensation, a constant molten pool depth can be obtained, so that the composition and crystal state of the upper and lower electroslag remelting ingots are consistent, the composition of the remelted ingots is more uniform, and the quality is improved to a certain extent.

[0055] The beneficial effects of the present invention are:

[0056] (1) The present invention adopts vacuum induction melting plus electroslag remelting two-step process technology to prepare CuMn 12 Ni3 precision resistance alloy can effectively eliminate impurities and sulfides in the ingot, and has a dense structure, uniform composition, and no defects such as shrinkage pores, inclusions, macroscopic and microscopic segregation.

[0057] (2) The present invention uses a mixture of CaO, Al2O3, CaF2 and SiO2 as a slag agent. CaF2 can reduce the melting point, viscosity and surface tension of the slag, promote the flow of the slag, separate the slag and the metal well, and promote desulfurization and dephosphorization in the smelting process; CaO can increase the basicity of the slag, improve the desulfurization efficiency, and reduce the electrical conductivity of the slag; Al2O3 can significantly reduce the electrical conductivity of the slag, reduce power consumption, and improve productivity; SiO2 can reduce the melting point of the slag, improve the high-temperature plasticity of the slag, make the surface of the ingot smooth, and better remove sulfides and other impurities in the material.

[0058] (3) The present invention heats the smelted materials slowly and evenly by adopting the method of gradually increasing the power, avoiding the influence of water vapor and oil stains existing in the dried materials on the materials. At the same time, the gradually increased power can effectively protect the equipment and avoid instantaneously excessive damage to the service life of the equipment. If the power is too small, the production efficiency will be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 is the as-cast metallographic structure 50 times that of Example 1 of the present invention;

[0060] Figure 2 is the as-cast metallographic structure 100 times that of Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0061] The present invention will be further described in detail below in conjunction with the specific embodiments to better reflect the advantages of the present invention.

[0062] Example 1

[0063] A method for preparing a high-performance CuMnNi alloy by a two-stage process, comprising the following steps:

[0064] S1. Vacuum induction melting of CuMn 12 Preparation of Ni3 precision resistance alloy ingots

[0065] S1-1. Batching

[0066] Weigh 12.3% of electrolytic manganese sheets, 3.0% of nickel plates and 84.7% of electrolytic copper plates by mass percentage, and mix them to obtain an alloy material;

[0067] S1-2. Loading the furnace

[0068] Load the alloy material obtained in S1-1 into the crucible furnace, close the furnace lid, close the air release valve, and clean the observation window;

[0069] S1-3. Vacuum pumping

[0070] Start the mechanical pump, open the low-vacuum baffle valve to pump vacuum, and start the Roots pump when the vacuum pressure in the crucible furnace is -0.08 MPa;

[0071] S1-4. Melting

[0072] When the vacuum degree is 10 Pa, heat up. When the alloy material in the crucible starts to melt, reduce the power to below 20 KW. Open the argon filling valve and fill the furnace body with argon with a purity of 99.9% (wt) at a filling rate of 5 L / min until the pressure in the crucible furnace rises to -0.08 Mpa, then close the argon filling valve. Then adjust the power to 60 KW and melt for 15 min. Among them, the heating and temperature rising method is: raise the power to 30 KW, keep warm for 5 min, raise the power to 45 KW, keep warm for 5 min, and raise the power to 65 KW and maintain it.

[0073] S1-5. Pouring

[0074] Adjust the power to 50 KW, keep it for 60 s and then pour. Among them, the pouring method is: water-cooled copper mold pouring, pouring time: 90 s.

[0075] S1-6. Taking out of the furnace

[0076] Stop heating, and take out the furnace after cooling for 30 min to obtain the CuMn 12 Ni3 vacuum ingot, and process it for standby. Among them, the processing method includes the following steps:

[0077] 1) Select the ingot that meets the sulfur content requirement

[0078] First, measure the sulfur content of the CuMn 12 Ni3 vacuum ingot obtained in step S1-6, select the vacuum melting CuMn with a sulfur content between 150 ppm 12 Ni3 ingot, and grind it to a diameter of 120 mm as the consumable electrode.

[0079] 2) Surface treatment

[0080] Use a shot blasting machine to grind the inclusions and oxides on the surface of the consumable electrode until the surface is bright, clean, without cracks, shrinkage cavities, air holes and inclusions.

[0081] 3) Oil stain treatment

[0082] Immerse the consumable electrode after surface treatment in the treatment solution for 2 min, then put the ultrasonic cleaner into the treatment solution and clean for 7 min, then take it out and put it into a container filled with distilled water and clean for 7 min. After taking it out, blow dry and blow clean the surface with nitrogen for standby. The treatment solution includes by mass percentage: 8% of anhydrous sodium silicate, 13% of fatty acid methyl ester ethoxylate sulfonate, 8% of phosphate ester salt, 13% of potassium hydroxide and the balance of water.

[0083] S2. Electroslag remelting of CuMn 12 Preparation of Ni3 precision resistance alloy ingot

[0084] S2-1. Selection of slag material

[0085] Select a binary slag system with 75% CaF2 and 25% Na3AlF6, and weigh 8 parts of CaO, 32 parts of Al2O3, 55 parts of CaF2, and 4 parts of SiO2 as raw materials by weight;

[0086] S2-2, drying

[0087] Place the raw materials weighed in step S2-1 in the furnace for drying. Drying temperature: 900 °C, drying time: 3 h;

[0088] S2-3, slag making

[0089] First, add CaF2 to the slag pool inside the mold and then start arc smelting. Then, add Al2O3, SiO2, and CaO in sequence for slag making to obtain an electroslag remelting slag capable of desulfurization. Among them, the slag-making parameters are: time: 27 min, slag-making voltage: 48 V, slag-making current: 2500 A;

[0090] S2-4, electroslag remelting

[0091] For the CuMn 12 The Ni3 vacuum-cast ingot self-consumable electrode is preheated at 250 °C for 25 min, then welded to the dummy electrode on the top of the slag pool, and the melting parameters are adjusted for electroslag remelting and feeding. After feeding, the molten metal solution flows through the slag pool to the bottom of the mold, cools at the bottom of the mold for 25 min, and then is demolded and air-cooled to obtain a vacuum electroslag remelting CuMn 12 Ni3 ingot; among them, the mass ratio of the electroslag remelting slag capable of desulfurization to the CuMn 12 Ni3 vacuum-cast ingot self-consumable electrode is 1:40; the adjusted melting parameters are voltage: 55 V, current: 5000 A; the feeding method is: adjust the starting current to 5000 A, and decrease the current by 520 A every 4 min until the current decreases to zero.

[0092] Example 2

[0093] Different from Example 1, in step S1-1, weigh 11.5% electrolytic manganese flakes, 3.2% nickel plates, and 85.3% electrolytic copper plates by mass percentage, and mix them to obtain an alloy material.

[0094] Example 3

[0095] Different from Example 1, in step S1-1, weigh 12.5% electrolytic manganese flakes, 2.8% nickel plates, and 84.7% electrolytic copper plates by mass percentage, and mix them to obtain an alloy material.

[0096] Example 4

[0097] Different from Example 1, in step S1-4, the heating and temperature rising method is as follows: the power is increased to 28KW, keep warm for 5 minutes, the power is increased to 43KW, keep warm for 5 minutes, and the power is increased to 63KW and maintained.

[0098] Example 5

[0099] Different from Example 1, in step S1-4, the heating and temperature rising method is as follows: the power is increased to 32KW, keep warm for 5 minutes, the power is increased to 47KW, keep warm for 5 minutes, and the power is increased to 67KW and maintained.

[0100] Example 6

[0101] Different from Example 1, in step S1-5, adjust the power to 45KW, keep it for 60s and then pour.

[0102] Example 7

[0103] Different from Example 1, in step S1-5, adjust the power to 55KW, keep it for 60s and then pour.

[0104] Example 8

[0105] Different from Example 1, in step S1-5, the pouring method is: pouring with a water-cooled copper mold, pouring time: 80s.

[0106] Example 9

[0107] Different from Example 1, in step S1-5, the pouring method is: pouring with a water-cooled copper mold, pouring time: 100s.

[0108] Example 10

[0109] Different from Example 1, in item 3) of step S1-6, the treatment solution includes by mass percentage: 5% of anhydrous sodium silicate, 12% of fatty acid methyl ester ethoxylate sulfonate, 5% of phosphate ester salt, 12% of potassium hydroxide and the balance of water;

[0110] Example 11

[0111] Different from Example 1, in item 3) of step S1-6, the treatment solution includes by mass percentage: 10% of anhydrous sodium silicate, 15% of fatty acid methyl ester ethoxylate sulfonate, 10% of phosphate ester salt, 15% of potassium hydroxide and the balance of water;

[0112] Example 12

[0113] Different from Example 1, in step S2-1, the slag system is a binary slag of 70-85% CaF2 and 15-30% MgF2.

[0114] Example 13

[0115] Different from Example 1, in step S2-1, the slag system is a binary slag with 70-80% CaF2 and 20-30% NaF2.

[0116] Example 14

[0117] Different from Example 1, in step S2-1, the slag system is a ternary slag with 60-80% CaF2, 15-30% MgF2, and 2-10% CaO.

[0118] Example 15

[0119] Different from Example 1, in step S2-1, the slag system is a rare earth ternary slag with 46-54% CaF2, 16-24% Al2O3, and 26-34% CeO.

[0120] Example 16

[0121] Different from Example 1, in step S2-1, the slag system is a quinary slag with 58-62% CaF2, 8-12% CaO, 8-12% Al2O3, 8-12% SiO2, and 8-12% MgO.

[0122] Example 17

[0123] Different from Example 1, in step S2-1, 6 parts of CaO, 30 parts of Al2O3, 50 parts of CaF2, and 3 parts of SiO2 are weighed by weight as raw materials.

[0124] Example 18

[0125] Different from Example 1, in step S2-1, 10 parts of CaO, 35 parts of Al2O3, 60 parts of CaF2, and 5 parts of SiO2 are weighed by weight as raw materials.

[0126] Example 19

[0127] Different from Example 1, in step S2-2, the drying temperature is 850 °C and the drying time is 4 h.

[0128] Example 20

[0129] Different from Example 1, in step S2-2, the drying temperature is 950 °C and the drying time is 2 h.

[0130] Example 21

[0131] Different from Example 1, in step S2-3, the slag-making parameters are: time: 25-30 min, slag-making voltage: 45-50 V, slag-making current: 500 A - 3500 A.

[0132] Example 22

[0133] Different from Example 1, in step S2-3, the slag-making parameters are as follows: time: 25-30 min, slag-making voltage: 45-50 V, slag-making current: 500 A-3500 A.

[0134] Example 23

[0135] Different from Example 1, in step S2, the mass ratio of the desulfurizable electroslag remelting slag to the CuMn 12 Ni3 vacuum-cast ingot consumable electrode is 1:30.

[0136] Example 24

[0137] Different from Example 1, in step S2, the mass ratio of the desulfurizable electroslag remelting slag to the CuMn 12 Ni3 vacuum-cast ingot consumable electrode is 1:50.

[0138] Example 25

[0139] Different from Example 1, in step S2-4, the adjusted melting parameters are voltage: 53 V, current: 4000 A.

[0140] Example 26

[0141] Different from Example 1, in step S2-4, the adjusted melting parameters are voltage: 58 V, current: 6000 A.

[0142] Example 27

[0143] Different from Example 1, in step S2-4, the feeding method is: adjust the starting current to 4000 A, and decrease the current by 500 A every 5 min until the current decreases to zero.

[0144] Example 28

[0145] Different from Example 1, in step S2-4, the feeding method is: adjust the starting current to 6000 A, and decrease the current by 550 A every 3 min until the current decreases to zero.

[0146] Control Example

[0147] Control Example 1: Different from Example 1, in step S1-6, the sulfur content of the vacuum-melted CuMn 12 Ni3 ingot consumable electrode is not limited;

[0148] Control Example 2: Different from Example 1, in step S1-4, the heating method is: directly increase the power to 63 KW and maintain it.

[0149] Comparative Example 3: Different from Example 1, in step S1-5, the pouring method is: pouring in a steel mold.

[0150] Comparative Example 4: Different from Example 1, in step S2-4, the mass ratio of the desulfurizable electroslag remelting slag to the consumable electrode for vacuum ingot casting is 1:10.

[0151] Comparative Example 5: Different from Example 1, in step S2-4, no feeding operation is carried out.

[0152] Experimental Example

[0153] The chemical compositions and properties of the CuMn 12 Ni3 precision resistance alloy materials prepared by the two-stage process of vacuum induction melting plus electroslag remelting were respectively detected for Examples 1 to 28 and Comparative Examples 1 to 5;

[0154] 1) Explore the influence of the sulfur content in the consumable electrode of vacuum-melted CuMn 12 Ni3 ingots on the chemical composition of the prepared CuMn 12 Ni3 alloy materials

[0155] Table 1 Chemical composition detection of CuMn 12 Ni3 alloy materials obtained in Examples 1 to 3

[0156]

[0157] Conclusion: From the data in Table 1, it can be obtained that the inclusions in the CuMn 12 Ni3 alloy materials prepared in Examples 1 to 3 are less, the structure is uniform, while in Comparative Example 1, due to the lack of limitation on the sulfur content in the hollow melting, the sulfur content in the final electroslag remelted ingot is too high, thus reducing the hot plasticity of the alloy and further affecting the performance of the material.

[0158] 2) Explore the influence of power gradient heating on the properties of CuMn 12 Ni3 alloy materials

[0159] Table 2 Performance detection of CuMn 12 Ni3 alloy materials prepared in Examples 1, 4, 5 and Comparative Example 2

[0160]

[0161] Conclusion: From the data of Examples 1, 4, 5 and Comparative Example 2, it can be obtained that the CuMn 12 Ni3 alloy materials obtained by power gradient heating in Examples 1, 4, 5 are compared with the CuMn 12The Ni3 alloy material is more stable and its various properties are also superior to those of Comparative Example 2. The reason is that the materials melted during the power gradient increase are heated slowly and evenly, and the water vapor and oil stains present in the materials are dried, avoiding the influence of water vapor and oil stains on the material.

[0162] 3) Explore the influence of pouring methods and pouring parameters on CuMn 12 the properties of Ni3 alloy materials

[0163] Table 3 Performance detection of CuMn 12 Ni3 alloy materials prepared in Example 1, Examples 6-9, and Comparative Example 3

[0164]

[0165]

[0166] Conclusion: From the data of Example 1, Examples 6-9, and Comparative Example 3, it can be seen that the pouring parameters have little influence on the properties of the CuMn 12 Ni3 alloy materials. In terms of the pouring method, the forced cooling effect of the water-cooled copper mold used in Example 1, Examples 6-9 in this application is better. The second-phase particles precipitated after aging do not have time to grow, so they are finer and more uniformly dispersed. However, since the thermal conductivity of the steel mold in Comparative Example 3 is lower than that of the copper mold, the cooling time of the alloy liquid is longer, and the second-phase particles precipitated after aging are prone to eutectic tendency and segregation, resulting in a decrease in various properties.

[0167] 4) Explore the influence of the mass ratio of desulfurizable electroslag remelting slag and vacuum ingot consumable electrode on CuMn 12 the properties of Ni3 alloy materials

[0168] Table 4 Performance detection of CuMn 12 Ni3 alloy materials prepared in Example 1, Examples 23-24, and Comparative Example 4

[0169]

[0170]

[0171] Conclusion: From the data of Example 1, Examples 23-24, and Comparative Example 4, it can be obtained that when the mass ratio of desulfurizable electroslag remelting slag and vacuum ingot consumable electrode is lower than the scope of this application, that is, the slag amount is low, it is easy to cause unsatisfactory desulfurization and slag removal effects of the remelted ingot and the deterioration of alloy properties.

[0172] 5) Explore the influence of the feeding process on CuMn 12 the properties of Ni3 alloy materials

[0173] Table 5 Performance detection of CuMn 12 Ni3 alloy materials prepared in Examples 1, 27 - 28 and Comparative Example 5

[0174]

[0175] Conclusion: From the data of Example 1, Examples 27 - 28 and Comparative Example 5, it can be obtained that in Example 1 and Examples 27 - 28, decreasing power feeding can make the composition and crystallization state of the electroslag remelting ingot consistent up and down, the composition of the remelting ingot more uniform, and the quality improved to a certain extent, thus improving the various properties of the alloy material.

Claims

1. A method for preparing a high-performance CuMnNi alloy by a two-stage process, characterized in that, It includes the following steps: S1. Vacuum induction melting of CuMn 12 Preparation of Ni3 precision resistance alloy ingots S1-1, batching Weigh 11.5~12.5% of electrolytic manganese sheets, 2.7~3.2% of nickel plates and 84.5~85.8% of electrolytic copper plates by mass percentage, and mix them to obtain alloy materials; S1-2, charging into the furnace Put the alloy materials obtained in S1-1 into the crucible furnace, close the furnace cover, close the air release valve, and clean the observation window; S1-3, vacuum pumping Start the mechanical pump, open the low-vacuum baffle valve to pump vacuum, and start the Roots pump when the vacuum pressure in the crucible furnace ≤ -0.08 MPa; S1-4, melting When the vacuum degree ≤ 10 Pa, heat up. When the alloy materials in the crucible furnace start to melt, reduce the power to below 20 KW, open the argon filling valve, and fill the furnace body with argon with a purity ≥ 99.9 wt.% at a filling rate of 4~6 L / min until the pressure in the crucible furnace rises to -0.08 MPa, then close the argon filling valve, and then adjust the power to 60 KW and melt for 10~15 min; In S1-4, the heating and temperature rising method is: raise the power to 28~32 KW, keep warm for 5 min, raise the power to 43~47 KW, keep warm for 5 min, and raise the power to 63~67 KW and maintain; S1-5, pouring Adjust the power to 45~55 KW, keep for 60 s and then pour; In S1-5, the pouring method is: pouring with a water-cooled copper mold, pouring time: 80~100 s; S1-6, taking out of the furnace Stop heating, and take out the product after cooling for 30 minutes to obtain CuMn 12 Ni3 vacuum ingot, and process it for standby; in S1-6, the processing method includes the following steps: 1) Select ingots that meet the sulfur content requirements First, measure the sulfur content of the CuMn 12 Ni3 vacuum ingot obtained in steps S1-6, and select a vacuum-melted CuMn 12 Ni3 ingot with a sulfur content between 100 and 200 ppm and grind it to a diameter of 100-150 mm as a consumable electrode; 2) Surface treatment Use a shot blasting machine to grind the inclusions and oxides on the surface of the consumable electrode until the surface is bright, clean, without cracks, shrinkage cavities, gas holes, and inclusions; 3) Oil stain treatment Put the consumable electrode after surface treatment into the treatment solution and soak for 2~3 min, then put the ultrasonic cleaner into the treatment solution and clean for 5~10 min, then take it out and put it into a container filled with distilled water and clean for 5~10 min, take it out and then blow dry and clean the surface with nitrogen for standby; The treatment solution includes by mass percentage: 5~10% of anhydrous sodium silicate, 12~15% of fatty acid methyl ester ethoxylate sulfonate, 5~10% of phosphate ester salt, 12~15% of potassium hydroxide and the balance of water; S2. Electroslag remelting of CuMn 12 Preparation of Ni3 precision resistance alloy ingot S2-1, slag material selection Select a binary slag system of 70~80% CaF2 and 20~30% Na3AlF6, and weigh 6~10 parts of CaO, 30~35 parts of Al2O3, 50~60 parts of CaF2 and 3~5 parts of SiO2 as raw materials by weight; S2-2, drying Put the raw materials weighed in step S2-1 into the furnace for drying, drying temperature: 850~950 °C, drying time: 2~4 h; S2-3, slag making First, add CaF2 into the slag pool inside the mold and then start arc melting. Then, add Al2O3, SiO2, and CaO in sequence to make slag, obtaining an electroslag remelting slag capable of desulfurization; the mass ratio of the electroslag remelting slag capable of desulfurization to the CuMn 12 Ni3 vacuum ingot consumable electrode is 1:30 to 50; S2-4, electroslag remelting For the CuMn obtained in steps S1-6 12 The Ni3 vacuum ingot consumable electrode is preheated at 200-250 °C for 20-30 min, then welded to the dummy electrode at the top of the slag pool, the melting parameters are adjusted for electroslag remelting, feeding, and the molten metal solution after feeding flows through the slag pool to the bottom of the mold, cools at the bottom of the mold for 20-30 min, and then is demolded and air-cooled to obtain the vacuum electroslag remelted CuMn 12 Ni3 ingot; in S2-4, the feeding method is: adjust the starting current to 4000-6000 A, and decrease the current by 500-550 A every 3-5 min until the current decreases to zero.

2. The method for preparing a high-performance CuMnNi alloy by a two-step process according to claim 1, wherein, In S2-1, the slag system can also adopt any one of the following: binary slag with 70 - 85% CaF2 and 15 - 30% MgF2, or binary slag with 70 - 80% CaF2 and 20 - 30% NaF, or ternary slag with 60 - 80% CaF2, 15 - 30% MgF2 and 2 - 10% CaO, or rare earth ternary slag with 46 - 54% CaF2, 16 - 24% Al2O3 and 26 - 34% CeO, or quinary slag with 58 - 62% CaF2, 8 - 12% CaO, 8 - 12% Al2O3, 8 - 12% SiO2 and 8 - 12% MgO.

3. A method for preparing a high-performance CuMnNi alloy by a two-step process according to claim 1, characterized in that, In S2-3, the slag-making parameters are as follows: slag-making time: 25 - 30 min, slag-making voltage: 45 - 50 V, slag-making current: 500 A - 3500 A.

4. A method for preparing a high-performance CuMnNi alloy by a two-stage process according to claim 1, characterized in that, In S2-4, the adjusted smelting parameters are voltage: 53 - 58 V, current: 4000 - 6000 A.

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