Preparation method of chromium-zirconium-copper wire for rivet electrical contact

Abstract

The invention relates to the technical field of electrical contact wires, in particular to a preparation method of a chromium-zirconium-copper wire for a rivet electrical contact, which comprises the following steps: S1, non-vacuum melting; s2, casting; s3, hot extrusion; s4, cold rolling and solid solution treatment; s5, drawing and aging; s6, carrying out online annealing; the chromium-zirconium-copper alloy has good electrical conductivity and thermal conductivity, high strength, good wear resistance and high softening temperature. The chromium-zirconium-copper alloy serves as an electrical contact material, high cost of an Ag-based material is avoided, the strength, the softening temperature and the abrasion resistance of a Cu-based material are improved, and compared with a traditional preparation process of a chromium-zirconium-copper wire, the preparation method has the advantages of being high in production efficiency, stable in quality, capable of achieving continuous operation, capable of achieving large-scale production and the like.

Description

Technical Field

[0001] The invention relates to the technical field of electric contact wires, and in particular to a method for preparing a chromium-zirconium-copper wire for a rivet electric contact. Background Art

[0002] The main requirements for electrical contacts in the electrical field are: high electrical conductivity, high strength requirements, good wear resistance and good plasticity. Pure copper wire is used as the raw material for rivet contacts. It has electrical conductivity and thermal conductivity second only to silver. Compared with silver, it has greater strength and hardness, higher melting point, lower price and easier processing. However, the surface of pure copper wire is easily oxidized, and the oxidation product has extremely low electrical conductivity, which sharply increases the contact resistance, making the material easy to heat up during use, causing the electrical contact performance of the material to decline rapidly. In addition, pure copper wire will fail during use due to decreased strength and low deformation resistance, which seriously affects the service life of electrical switches. At the same time, pure copper wire often cannot meet the requirements for temperature, elasticity, corrosion resistance, high temperature strength, etc. Therefore, copper and general copper alloys are difficult to be used as electrical contact materials for air, and their application range is greatly limited.

[0003] Chromium-zirconium-copper alloy has good electrical conductivity, thermal conductivity, high strength, good wear resistance, and high softening temperature. As an electrical contact material, chromium-zirconium-copper alloy avoids the high cost of Ag-based materials and improves the strength, softening temperature and wear resistance of Cu-based materials, and has a wider application prospect. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for preparing chromium-zirconium-copper wire for rivet electrical contacts.

[0005] A method for preparing a chromium-zirconium-copper wire for a rivet electrical contact comprises the following steps:

[0006] S1. Non-vacuum melting:

[0007] Loading raw materials into the furnace, wherein the raw materials include, by mass percentage, 0.6-1.3% Cr, 0.04-0.15% Zr, and the balance Cu;

[0008] When the furnace is loaded to 1 / 2 of the crucible, start to gradually increase the temperature until the melt is clear, and then carry out degassing and refining for 0.5 to 1 hour;

[0009] S2. Casting:

[0010] The launder, the draft tube, and the crystallizer are continuously baked for 1.5 to 2.5 hours to 600 to 800°C, and the melt obtained in step S1 is heated to 1200 to 1300°C, and then the melt is introduced into the crystallizer. When the liquid level in the launder is greater than 70%, the stopper rod is opened, and cooling water at 25 to 35°C is introduced into the crystallizer at a flow rate of 45 to 65 L / min. Argon is introduced into the crucible to make the pressure reach 4 to 7 Bar, and the argon flow rate is 30 to 40 L / min.

[0011] When the liquid level in the crystallizer is 20 to 50 mm, casting is performed at a speed of 10 to 50 mm / min for 1 to 5 hours to obtain an ingot;

[0012] S3, hot extrusion:

[0013] The ingot is hot extruded on a hot extruder at a heating temperature of 850 to 950° C., an extrusion speed of 5 to 15 mm / s, and an extrusion time of 20 to 60 s to obtain a rod;

[0014] S4, cold rolling and solution treatment:

[0015] The bar material is rolled on a rolling mill for 4 to 8 times, with a deformation of 15 to 30% in each rolling time and a rolling speed of 0.25 to 0.35 m / s, and then coiled, and the coiled bar material is subjected to solution heat treatment;

[0016] S5, drawing and aging:

[0017] The solutionized rod is drawn and peeled on a disc drawing machine for 7 to 10 times, with a deformation of 10 to 30% in each drawing process, to obtain a wire, which is then subjected to aging heat treatment and wire drawing, with a deformation of 30 to 60%;

[0018] S6, online annealing:

[0019] The S5 wire after drawing is subjected to tubular online annealing, heated to 550-650°C at a heating rate of 4-6°C / min, kept warm for 30-120s, and the motor speed is 200-500r / min.

[0020] Furthermore, in step S1, the Cu element is used as a raw material in the form of an oxygen-free copper rod, the Cr element is used as a raw material in the form of a Cr cored wire, and the Zr element is used as a raw material in the form of a CuZr50 cored wire.

[0021] Description: Oxygen-free copper rod improves the purity of copper, which helps to improve electrical conductivity and thermal conductivity. In non-vacuum smelting, the use of oxygen-free copper can reduce the reaction between copper and oxygen during smelting and avoid the formation of copper oxide, thereby improving the accuracy of alloy composition control. Under non-vacuum conditions, some elements are easy to volatilize, and the structure of Cr cored wire can reduce the volatilization loss of chromium during smelting and maintain the stability of the composition. After the cored wire is added to the molten pool, the chromium element can be more evenly distributed throughout the alloy, avoiding local enrichment or depletion. Zr element is easy to react with oxygen under non-vacuum conditions. The use of CuZr50 cored wire can protect the Zr element and improve the smelting efficiency and the stability of the alloy composition.

[0022] Furthermore, in step S1, the gradient heating method is: first increase the power to 200-300KW, keep warm for 20-40min, then increase the power to 500-600KW, keep warm for 20-40min, and finally increase the power to 700-800KW, keep warm for 20-40min.

[0023] Description: Gradient heating can make the smelting process smoother, help the uniform dissolution and mixing of alloy elements, and reduce melt splashing and gas entrapment caused by rapid heating; by slowly heating, the reaction of alloy elements with air or furnace lining materials can be reduced, thereby reducing burn-off and maintaining the consistency and stability of alloy composition; gradient heating helps to reduce pores and inclusions in the melt, improve the density and surface quality of castings, reduce macro and micro segregation, and thus improve the performance of the final product; an appropriate heating rate can maintain good fluidity of the melt, facilitate uniform filling of the alloy liquid during pouring, and reduce casting defects such as cold shuts and shrinkage cavities.

[0024] Furthermore, in step S4, the method of the solution heat treatment is: heating to 850-980°C at a heating rate of 4-6°C / min, keeping the temperature for 30-90min, and rapidly cooling to room temperature with water after being taken out of the furnace.

[0025] Note: The above heating rate can help the material to heat up slowly, reduce the thermal stress caused by temperature difference, and avoid premature cracks or other defects in the material. Such a heating rate is conducive to uniform heating inside the material, ensuring that the alloy elements are fully diffused and achieving the expected solid solution effect. The above holding time is sufficient to ensure that the chemical components inside the copper-chromium-zirconium alloy are fully mixed and diffused, and it also helps the uniform growth of grains. Sufficient holding time helps to eliminate stress concentration generated during casting or molding and improve the overall performance of the material.

[0026] Furthermore, in step S5, the aging heat treatment method is: heating to 530-550°C at a heating rate of 4-6°C / min, keeping the temperature for 1.5-5.5h, and air cooling to room temperature after being taken out of the furnace.

[0027] Note: The above heating rate helps to reduce thermal stress and avoid uneven heating inside the material, thereby promoting the homogenization of the internal structure of the material. The above holding time can ensure that the phase change inside the alloy is fully carried out, which helps to form a more uniform and fine microstructure, which is very beneficial for improving the mechanical properties and corrosion resistance of the alloy. The air cooling process can reduce defects such as internal stress and cracking caused by rapid cooling, and help maintain the integrity and performance stability of the alloy.

[0028] Furthermore, in step S6, the method of drawing and peeling is as follows: the first and second passes are both drawing, the third pass is peeling with a peeling amount of 20 to 30 mm, the fourth pass is drawing, the fifth pass is peeling with a peeling amount of 10 to 20 mm, and subsequent passes are all drawing.

[0029] Description: Through multiple cycles of drawing and peeling, defects and unevenness on the material surface, such as oxide layer, scratches or other surface contamination, can be gradually removed. Through segmented drawing and peeling, the deformation and stress distribution of the material during processing can be better controlled, which helps to reduce material damage caused by uneven deformation and ensure the geometric size and shape accuracy of the product.

[0030] Further, in step S4, when the total number of rolling passes is ≥6, the even-numbered rolling passes in the total number of rolling passes are rolled using a differential temperature rolling method, wherein the temperature of the upper rolling roll is lower than the temperature of the lower rolling roll, and the steps are as follows:

[0031] Second pass: the temperature difference between the upper roller and the lower roller is 100-120°C, the temperature of the upper roller is 25-50°C, the speed ratio of the upper roller to the lower roller is 1:3-4, and the rolled material is subjected to a differential temperature rolling, and the rolled material is subjected to 10-15 ultrasonic rolling in the X direction, the static pressure of the ultrasonic rolling is 250-300N, the cutting speed is 1200-1500mm / min, and the frequency of the ultrasonic generator is 20-22kHz;

[0032] The fourth pass: the temperature difference between the upper roller and the lower roller is 140-160°C, the temperature of the upper roller is 40-60°C, the speed ratio of the upper roller to the lower roller is 1:4-5, and the rolled material is obtained by secondary temperature differential rolling, and the rolled material is adjusted to the Y direction for 20-25 ultrasonic rolling, the static pressure of the ultrasonic rolling is 320-340N, the cutting speed is 1200-1500mm / min, and the frequency of the ultrasonic generator is 25-30kHz;

[0033] The sixth pass: the temperature difference between the upper roller and the lower roller is 80-100°C, the temperature of the upper roller is 25-40°C, the speed ratio of the upper roller to the lower roller is 1:3-4, and the rolled material is obtained by three temperature differential rolling, and the rolled material is adjusted to the X direction for 10-15 times of ultrasonic rolling, the static pressure of the ultrasonic rolling is 200-230N, the tool speed is 1200-1500mm / min, and the frequency of the ultrasonic generator is 20-22kHz.

[0034] Description: Differential temperature rolling utilizes the influence of different temperatures on the plastic deformation of materials, which helps to refine grains and improve the strength and toughness of materials. Combining differential temperature rolling and ultrasonic rolling can achieve simultaneous improvement of material strength, plasticity and toughness.

[0035] Using a higher temperature difference in the fourth pass can more significantly promote grain refinement, while using a lower temperature difference in the sixth pass can control excessive grain refinement and maintain good plasticity. By controlling the rolling temperature of different passes, the stress distribution inside the material can be adjusted, the residual stress can be reduced, and the dimensional stability and fatigue performance of the material can be improved.

[0036] Ultrasonic rolling can produce tiny plastic deformation on the surface of the material, introduce beneficial residual compressive stress, and refine the grains of the surface layer. Ultrasonic rolling after differential temperature rolling can further optimize the microstructure of the material surface and improve the surface hardness and wear resistance.

[0037] Compared with the existing preparation method of chromium zirconium copper wire, the beneficial effects of the present invention are:

[0038] (1) Chromium-zirconium-copper alloy has good electrical conductivity, thermal conductivity, high strength, good wear resistance, and high softening temperature. As an electrical contact material, chromium-zirconium-copper alloy avoids the high cost of Ag-based materials and improves the strength, softening temperature and wear resistance of Cu-based materials. Compared with the preparation process of traditional chromium-zirconium-copper wire, the present invention has the advantages of high production efficiency, stable quality, continuous operation, and large-scale production.

[0039] (2) The present invention performs differential temperature rolling and ultrasonic rolling at intervals during cold rolling. A higher differential temperature is used in the fourth pass to more significantly promote grain refinement, while a lower differential temperature is used in the sixth pass to control excessive grain refinement and maintain good plasticity. By controlling the rolling temperature of different passes, the stress distribution inside the material can be adjusted, residual stress can be reduced, and the dimensional stability and fatigue performance of the material can be improved. Ultrasonic rolling can produce tiny plastic deformation on the surface of the material, introduce beneficial residual compressive stress, and refine the grains of the surface layer at the same time. Ultrasonic rolling is performed after differential temperature rolling to further optimize the microstructure of the material surface and improve the surface hardness and wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a conductivity comparison diagram of the exploration 2 of the preparation method of the copper-chromium-zirconium wire of the present invention;

[0041] Figure 2 It is a tensile strength comparison diagram of the research 2 of the preparation method of the copper-chromium-zirconium wire of the present invention;

[0042] Figure 3 It is a conductivity comparison diagram of the exploration 3 of the preparation method of the copper-chromium-zirconium wire of the present invention;

[0043] Figure 4 It is a tensile strength comparison chart of the investigation 3 of the preparation method of the copper-chromium-zirconium wire of the present invention. DETAILED DESCRIPTION

[0044] In order to further illustrate the method adopted by the present invention and the effect achieved, the technical solution of the present invention will be clearly and completely described in combination with experiments below.

[0045] Embodiment 1: A method for preparing a chromium-zirconium-copper wire for a rivet electrical contact, comprising the following steps:

[0046] S1. Non-vacuum melting:

[0047] The raw materials are charged into the furnace, wherein the raw materials include, by mass percentage, 0.9% Cr, 0.09% Zr, and the balance Cu; the Cu element is used as a raw material in the form of an oxygen-free copper rod, the Cr element is used as a raw material in the form of a Cr cored wire, and the Zr element is used as a raw material in the form of a CuZr50 cored wire;

[0048] When the furnace is loaded to 1 / 2 of the crucible, the temperature is gradually increased until the melt is completely melted, and magnesium oxide accounting for 3% of the melt is added to the crucible for degassing and refining for 0.8 hours; the method of the gradient temperature increase is: first increase the power to 250KW, keep warm for 30 minutes, then increase the power to 550KW, keep warm for 30 minutes, and finally increase the power to 750KW, keep warm for 30 minutes;

[0049] S2. Casting:

[0050] The launder, the draft tube, and the crystallizer are baked to 700°C for 2 hours, and the melt obtained in step S1 is heated to 1250°C, and then the melt is introduced into the crystallizer. When the liquid level in the launder is 75%, the stopper rod is opened, and cooling water at 30°C is passed into the crystallizer at a flow rate of 50 L / min. Argon is passed into the crucible to make the pressure reach 5.5 Bar, and the argon flow rate is 35 L / min;

[0051] When the liquid level in the crystallizer is 35 mm, casting is performed at a speed of 30 mm / min for 3 h. Ingots;

[0052] S3, hot extrusion:

[0053] The ingot was hot extruded on a hot extruder at a heating temperature of 900°C, an extrusion speed of 10 mm / s, and an extrusion time of 40 s to obtain of bar stock;

[0054] S4, cold rolling and solution treatment:

[0055] The bar material is rolled on a rolling mill for 4 to 8 times, with a deformation of 22% in each rolling time, a rolling speed of 0.2 m / s, an outer diameter of 12 mm, and coiled, and the coiled bar material is subjected to solution heat treatment; the solution heat treatment method is: heating to 915°C at a heating rate of 5°C / min, holding time of 60 minutes, and rapidly cooling to room temperature after being taken out of the furnace;

[0056] S5, drawing and aging:

[0057] The bar material after solid solution is drawn and peeled on a disc drawing machine for 9 times, and the deformation amount of each drawing is 20%. The drawing and peeling method is as follows: the first and second passes are drawing, the third pass is peeling, the peeling amount is 25mm, the fourth pass is drawing, the fifth pass is peeling, the peeling amount is 15mm, and the subsequent passes are all drawing. The wire is then heat treated and drawn to The deformation of the wire drawing is 45%; the aging heat treatment method is: heating to 540°C at a heating rate of 5°C / min, keeping the temperature for 3.5h, and air cooling to room temperature after being taken out of the furnace;

[0058] S6, online annealing:

[0059] The S5 wire after drawing was subjected to tubular online annealing, heated to 600°C at a heating rate of 5°C / min, kept at this temperature for 75s, and the motor speed was 350r / min.

[0060] Embodiment 2: This embodiment is different from Embodiment 1 in that the raw materials, calculated by mass percentage, include: Cr 0.6%, Z 0.15%, and the balance is Cu.

[0061] Example 3: This example is different from Example 1 in that the raw materials, calculated by mass percentage, include: Cr 1.3%, Zr 0.04%, and the balance is Cu.

[0062] Example 4: The difference between this example and Example 1 is that the temperature is gradually increased until the melt is completely melted, and then degassing and refining are carried out for 0.5 hours; the method of the gradient temperature increase is: first increase the power to 200KW, keep warm for 20 minutes, then increase the power to 600KW, keep warm for 20 minutes, and finally increase the power to 700KW, keep warm for 20 minutes.

[0063] Example 5: The difference between this example and Example 1 is that the temperature is gradually increased until the melt is completely melted, and then degassing and refining are carried out for 1 hour; the method of the gradient temperature increase is: first increase the power to 300KW, keep warm for 40 minutes, then increase the power to 500KW, keep warm for 40 minutes, and finally increase the power to 800KW, keep warm for 40 minutes.

[0064] Example 6: This example is different from Example 1 in that the launder, the drainage tube, and the crystallizer are continuously baked for 1.5 hours to 600°C, and the melt obtained in step S1 is heated to 1200°C.

[0065] Example 7: This example is different from Example 1 in that the launder, the drainage tube, and the crystallizer are continuously baked for 2.5 hours to 800°C, and the melt obtained in step S1 is heated to 1300°C.

[0066] Example 8: This example is different from Example 1 in that cooling water at 25°C is passed at a flow rate of 45 L / min, and argon gas is passed so that the pressure reaches 4 Bar, and the argon flow rate is 30 L / min.

[0067] Example 9: This example is different from Example 1 in that cooling water at 35°C is passed at a flow rate of 65 L / min, and argon gas is passed so that the pressure reaches 7 Bar, and the argon flow rate is 40 L / min.

[0068] Example 10: This example is different from Example 1 in that when the liquid level in the crystallizer is 20 mm, casting is performed at a speed of 10 mm / min.

[0069] Example 11: This example is different from Example 1 in that when the liquid level in the crystallizer is 50 mm, casting is performed at a speed of 50 mm / min.

[0070] Example 12: This example is different from Example 1 in that the heating temperature of hot extrusion is 850°C and the extrusion speed is 5 mm / s.

[0071] Example 13: This example is different from Example 1 in that the heating temperature of hot extrusion is 950°C and the extrusion speed is 15 mm / s.

[0072] Example 14: This example differs from Example 1 in that the bar is rolled on the rolling mill in four passes, the deformation in each pass is 15%, and the rolling speed is 0.25 m / s.

[0073] Example 15: This example differs from Example 1 in that the bar is rolled on the rolling mill for 8 passes, the deformation of each pass is 30%, and the rolling speed is 0.35 m / s.

[0074] Example 16: This example is different from Example 1 in that the method of solution heat treatment is: heating to 850°C at a heating rate of 4°C / min, keeping the temperature for 30 minutes, and rapidly cooling to room temperature with water after being taken out of the furnace.

[0075] Example 17: This example is different from Example 1 in that the method of solution heat treatment is: heating to 980°C at a heating rate of 6°C / min, keeping the temperature for 90 minutes, and rapidly cooling to room temperature with water after being taken out of the furnace.

[0076] Example 18: The difference between this example and Example 1 is that the bar material after solid solution is drawn and stripped on a disc drawing machine through 7 passes, and the deformation amount of each drawing pass is 10%. The drawing and stripping method is as follows: the first pass and the second pass are both drawing, the third pass is stripping, the stripping amount is 20mm, the fourth pass is drawing, the fifth pass is stripping, the stripping amount is 10mm, and the subsequent passes are all drawing to obtain wire, which is then subjected to aging heat treatment and wire drawing, and the deformation amount of wire drawing is 30%.

[0077] Example 19: The difference between this example and Example 1 is that the bar material after solid solution is drawn and stripped on a disc drawing machine for 10 times, and the deformation amount of each drawing time is 20%. The drawing and stripping method is as follows: the first and second passes are both drawing, the third pass is stripping, and the stripping amount is 30mm, the fourth pass is drawing, the fifth pass is stripping, and the stripping amount is 20mm, and the subsequent passes are all drawing to obtain wire, which is then subjected to aging heat treatment and wire drawing, and the deformation amount of wire drawing is 60%.

[0078] Example 20: This example is different from Example 1 in that the aging heat treatment method is: heating to 530°C at a heating rate of 4°C / min, keeping warm for 1.5h, and air cooling to room temperature after being taken out of the furnace.

[0079] Example 21: This example is different from Example 1 in that the aging heat treatment method is: heating to 550°C at a heating rate of 6°C / min, keeping warm for 5.5h, and air cooling to room temperature after being taken out of the furnace.

[0080] Example 22: This example is different from Example 1 in that the wire after S5 drawing is subjected to tubular online annealing, heated to 550°C at a heating rate of 4°C / min, kept warm for 30s, and the motor speed is 200r / min.

[0081] Example 23: This example is different from Example 1 in that the S5 wire after drawing is subjected to tubular online annealing, heated to 650°C at a heating rate of 6°C / min, kept warm for 120s, and the motor speed is 500r / min.

[0082] Embodiment 24: This embodiment differs from Embodiment 1 in that, in step S4, when the total number of rolling passes is ≥ 6, the even-numbered rolling passes in the total number of rolling passes are rolled by a differential temperature rolling method, wherein the temperature of the upper roll is lower than the temperature of the lower roll, and the steps are as follows:

[0083] Second pass: the temperature difference between the upper roller and the lower roller is 110°C, the temperature of the upper roller is 35°C, the speed ratio of the upper roller to the lower roller is 1:3.5, and the rolled material is subjected to a differential temperature rolling, and the rolled material is subjected to 13 ultrasonic rollings in the X direction, the static pressure of the ultrasonic rolling is 275N, the cutting speed is 1350mm / min, and the frequency of the ultrasonic generator is 21kHz;

[0084] The fourth pass: the temperature difference between the upper roller and the lower roller is 150°C, the temperature of the upper roller is 50°C, the speed ratio of the upper roller to the lower roller is 1:4.5, and the rolled material is obtained by secondary temperature differential rolling, and the rolled material is adjusted to the Y direction for 23 ultrasonic rolling, the static pressure of the ultrasonic rolling is 330N, the cutting speed is 1350mm / min, and the frequency of the ultrasonic generator is 28kHz;

[0085] The sixth pass: the temperature difference between the upper roller and the lower roller is 90°C, the temperature of the upper roller is 32°C, the speed ratio of the upper roller to the lower roller is 1:3.5, and the rolled material is obtained by three times of differential temperature rolling. The rolled material is adjusted to the X direction for 13 times of ultrasonic rolling. The static pressure of the ultrasonic rolling is 215N, the tool speed is 1350mm / min, and the frequency of the ultrasonic generator is 21kHz.

[0086] Example 25: The difference between this example and Example 24 is that, in the second pass: the temperature difference between the upper roller and the lower roller is 100°C, the temperature of the upper roller is 25°C, and the speed ratio of the upper roller to the lower roller is 1:3.

[0087] Example 26: The difference between this example and Example 24 is that, in the second pass: the temperature difference between the upper roller and the lower roller is 120°C, the temperature of the upper roller is 50°C, and the speed ratio of the upper roller to the lower roller is 1:4.

[0088] Example 27: The difference between this example and Example 24 is that, in the fourth pass: the temperature difference between the upper roller and the lower roller is 140°C, the temperature of the upper roller is 40°C, and the speed ratio of the upper roller to the lower roller is 1:4.

[0089] Example 28: The difference between this example and Example 24 is that, in the fourth pass: the temperature difference between the upper roller and the lower roller is 160°C, the temperature of the upper roller is 60°C, and the speed ratio of the upper roller to the lower roller is 1:5.

[0090] Example 29: The difference between this example and Example 24 is that, in the sixth pass: the temperature difference between the upper roller and the lower roller is 80°C, the temperature of the upper roller is 25°C, and the ratio of the upper roller speed to the lower roller speed is 1:3.

[0091] Example 30: The difference between this example and Example 24 is that, in the sixth pass: the temperature difference between the upper roller and the lower roller is 100°C, the temperature of the upper roller is 40°C, and the speed ratio of the upper roller to the lower roller is 1:4.

[0092] Example 31: The difference between this example and Example 24 is that, in the second pass: the rolled material is ultrasonically rolled 10 times in the X direction, the static pressure of the ultrasonic rolling is 250N, the tool speed is 1200mm / min, and the frequency of the ultrasonic generator is 20kHz.

[0093] Example 32: This example differs from Example 24 in that, in the second pass, the rolled material is ultrasonically rolled 15 times in the X direction, the static pressure of the ultrasonic rolling is 300N, the tool speed is 1500mm / min, and the frequency of the ultrasonic generator is 22kHz.

[0094] Example 33: The difference between this example and Example 24 is that, in the fourth pass: the rolled material is adjusted to the Y direction for 20 ultrasonic rolling operations, the static pressure of the ultrasonic rolling is 320N, the tool speed is 1200mm / min, and the frequency of the ultrasonic generator is 25kHz.

[0095] Example 34: The difference between this example and Example 24 is that, in the fourth pass: the rolled material is adjusted to the Y direction for 25 ultrasonic rolling steps, the static pressure of the ultrasonic rolling is 340N, the tool speed is 1500mm / min, and the frequency of the ultrasonic generator is 30kHz.

[0096] Example 35: This example is different from Example 24 in that, in the sixth pass, the rolled material is adjusted to the X direction for 10 ultrasonic rolling operations, the static pressure of the ultrasonic rolling is 200N, the tool speed is 1200mm / min, and the frequency of the ultrasonic generator is 20kHz.

[0097] Example 36: This example is different from Example 24 in that, in the sixth pass, the rolled material is adjusted to the X direction for 15 ultrasonic rolling steps, the static pressure of the ultrasonic rolling is 230N, the tool speed is 1500mm / min, and the frequency of the ultrasonic generator is 22kHz.

[0098] Experimental Example: The description of this experimental example is based on the scheme described in Example 1, and is intended to illustrate the practical application effect of the present invention.

[0099] For the copper-chromium-zirconium wire prepared in each embodiment, the tensile strength and electrical conductivity were tested respectively, and the average value of the experimental values ​​of five tests each time was taken as the final result. The specific research is as follows:

[0100] 1. The various performance tests of Example 1 are shown in Table 1:

[0101] Table 1 Performance test results of Example 1

[0102]

[0103] It can be seen from Table 1 that the copper-chromium-zirconium wire prepared by the present invention has excellent electrical conductivity and mechanical properties.

[0104] 2. Investigate the influence of various parameters in the preparation of copper-chromium-zirconium wire on the tensile strength and electrical conductivity of copper-chromium-zirconium wire.

[0105] Depend on Figure 1 and Figure 2 By comparing the results of Examples 1 to 23, it can be seen that the proportion of zirconium in the raw material is too small or too large, the gradient temperature rise difference is too small or too large, the baking heating parameter is too small or too large, the cooling parameter is too small or too large, the casting parameter is too small or too large, the hot extrusion parameter is too small or too large, the rolling parameter is too small or too large, the solution heat treatment parameter is too small, the drawing parameter is too small or too large, the aging heat treatment parameter is too small, and the online annealing parameter is too small compared with Example 1. The tensile strength and conductivity of the copper-chromium-zirconium wire are reduced, among which the solution heat treatment parameters, aging heat treatment parameters and online annealing parameters are larger, the temperature used is higher and the time is longer, and the tensile strength is improved compared with Example 1, but the improvement is small and the conductivity is reduced. Therefore, from an economic point of view, the parameter effect of Example 1 is relatively better.

[0106] 3. Investigate the effects of differential temperature rolling and ultrasonic rolling on the tensile strength and electrical conductivity of copper-chromium-zirconium wire.

[0107] The difference between the comparative example 1 and the example 24 is that the parameters of the differential temperature rolling in each pass are the same;

[0108] The difference between Comparative Example 2 and Example 24 is that the direction of ultrasonic rolling in each pass is the same;

[0109] The difference between Control Example 3 and Example 24 is that the parameters of each ultrasonic rolling are the same;

[0110] Depend on Figure 3 and Figure 4 Comparing the results of Examples 24 to 36, it can be seen that the introduction of alternating differential temperature rolling and ultrasonic rolling during rolling improves the tensile strength and conductivity of the copper-chromium-zirconium wire compared with Examples 1 to 23, and the conductivity is more stable relative to that of Examples 1 to 23, which stabilizes the conductivity while improving the tensile strength to prevent it from decreasing significantly;

[0111] Among them, the control example 1 lacks the pass change of differential temperature rolling, the control example 2 lacks the direction change of ultrasonic rolling, and the control example 3 lacks the parameter change of ultrasonic rolling. Compared with Examples 24 to 36, the tensile strength and conductivity of the copper-chromium-zirconium wire are reduced. Therefore, the pass change of differential temperature rolling, the direction and parameter change of ultrasonic rolling all play a certain role in improving the tensile strength and conductivity of the copper-chromium-zirconium wire.

[0112] By comparing the results of Examples 24 to 36, it can be seen that if the differential temperature rolling parameters of the second, fourth and sixth passes are too small or too large, and the ultrasonic rolling parameters are too small or too large, the tensile strength and conductivity of the copper-chromium-zirconium wire will be reduced. Therefore, in comprehensive comparison, the parameter effect of Example 24 is relatively better.

Claims

1. A method for preparing chromium-zirconium-copper wire for rivet electrical contacts, It is characterized in that The following steps are involved: S1. Non-vacuum melting: Loading raw materials into the furnace, wherein the raw materials include, by mass percentage, 0.6-1.3% Cr, 0.04-0.15% Zr, and the balance Cu; When the furnace is loaded to 1 / 2 of the crucible, start to gradually increase the temperature until the melt is clear, and then carry out degassing and refining for 0.5 to 1 hour; S2. Casting: The launder, the draft tube, and the crystallizer are continuously baked for 1.5 to 2.5 hours to 600 to 800°C, and the melt obtained in step S1 is heated to 1200 to 1300°C, and then the melt is introduced into the crystallizer. When the liquid level in the launder is greater than 70%, the stopper rod is opened, and cooling water at 25 to 35°C is introduced into the crystallizer at a flow rate of 45 to 65 L / min. Argon is introduced into the crucible to make the pressure reach 4 to 7 Bar, and the argon flow rate is 30 to 40 L / min. When the liquid level in the crystallizer is 20 to 50 mm, casting is performed at a speed of 10 to 50 mm / min for 1 to 5 hours to obtain an ingot; S3, hot extrusion: The ingot is hot extruded on a hot extruder at a heating temperature of 850 to 950° C., an extrusion speed of 5 to 15 mm / s, and an extrusion time of 20 to 60 s to obtain a rod; S4, cold rolling and solution treatment: The bar material is rolled on a rolling mill for 4 to 8 times, with a deformation of 15 to 30% in each rolling time and a rolling speed of 0.25 to 0.35 m / s, and then coiled, and the coiled bar material is subjected to solution heat treatment; S5, drawing and aging: The solutionized rod is drawn and peeled on a disc drawing machine for 7 to 10 times, with a deformation of 10 to 30% in each drawing process, to obtain a wire, which is then subjected to aging heat treatment and wire drawing, with a deformation of 30 to 60%; S6, online annealing: The S5 wire after drawing is subjected to tubular online annealing, heated to 550-650°C at a heating rate of 4-6°C / min, kept warm for 30-120s, and the motor speed is 200-500r / min.

2. A method for preparing a chromium-zirconium-copper wire for a rivet electrical contact according to claim 1, It is characterized in that In step S1, the Cu element is used as a raw material in the form of an oxygen-free copper rod, the Cr element is used as a raw material in the form of a Cr cored wire, and the Zr element is used as a raw material in the form of a CuZr50 cored wire.

3. A method for preparing a chromium-zirconium-copper wire for a rivet electrical contact according to claim 1, It is characterized in that In step S1, the gradient heating method is: first increase the power to 200-300KW, keep warm for 20-40 minutes, then increase the power to 500-600KW, keep warm for 20-40 minutes, and finally increase the power to 700-800KW, keep warm for 20-40 minutes.

4. A method for preparing a chromium-zirconium-copper wire for a rivet electrical contact according to claim 1, It is characterized in that In step S4, the method of solution heat treatment is: heating to 850-980°C at a heating rate of 4-6°C / min, keeping the temperature for 30-90min, and rapidly cooling to room temperature with water after being taken out of the furnace.

5. The method for preparing a chromium-zirconium-copper wire for rivet electrical contacts according to claim 1, It is characterized in that In step S5, the aging heat treatment method is: heating to 530-550°C at a heating rate of 4-6°C / min, keeping the temperature for 1.5-5.5h, and air cooling to room temperature after being taken out of the furnace.

6. A method for preparing a chromium-zirconium-copper wire for a rivet electrical contact according to claim 1, It is characterized in that In step S6, the method of drawing and peeling is as follows: the first and second passes are drawing, the third pass is peeling with a peeling amount of 20 to 30 mm, the fourth pass is drawing, the fifth pass is peeling with a peeling amount of 10 to 20 mm, and subsequent passes are all drawing.

7. A method for preparing a chromium-zirconium-copper wire for a rivet electrical contact according to claim 1, It is characterized in that In step S4, when the total number of rolling passes is ≥6, the even-numbered rolling passes in the total number of rolling passes are rolled using a differential temperature rolling method, wherein the temperature of the upper rolling roll is lower than the temperature of the lower rolling roll, and the steps are as follows: Second pass: the temperature difference between the upper roller and the lower roller is 100-120°C, the temperature of the upper roller is 25-50°C, the speed ratio of the upper roller to the lower roller is 1:3-4, and the rolled material is subjected to a differential temperature rolling, and the rolled material is subjected to 10-15 ultrasonic rolling in the X direction, the static pressure of the ultrasonic rolling is 250-300N, the cutting speed is 1200-1500mm / min, and the frequency of the ultrasonic generator is 20-22kHz; The fourth pass: the temperature difference between the upper roller and the lower roller is 140-160°C, the temperature of the upper roller is 40-60°C, the speed ratio of the upper roller to the lower roller is 1:4-5, and the rolled material is obtained by secondary temperature differential rolling, and the rolled material is adjusted to the Y direction for 20-25 ultrasonic rolling, the static pressure of the ultrasonic rolling is 320-340N, the cutting speed is 1200-1500mm / min, and the frequency of the ultrasonic generator is 25-30kHz; The sixth pass: the temperature difference between the upper roller and the lower roller is 80-100°C, the temperature of the upper roller is 25-40°C, the speed ratio of the upper roller to the lower roller is 1:3-4, and the rolled material is obtained by three temperature differential rolling, and the rolled material is adjusted to the X direction for 10-15 times of ultrasonic rolling, the static pressure of the ultrasonic rolling is 200-230N, the tool speed is 1200-1500mm / min, and the frequency of the ultrasonic generator is 20-22kHz.

8. The method for preparing a chromium-zirconium-copper wire for rivet electrical contacts according to claim 1, It is characterized in that The deformation amount of each rolling pass is 15-30%.

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