Preparation method of chromium-zirconium-copper contact line blank

Abstract

The invention belongs to the technical field of contact wires, and relates to a preparation method of a chromium-zirconium-copper contact wire blank, which comprises the following steps: (1) vacuum induction melting: carrying out vacuum induction melting on raw materials comprising 0.8% of chromium, 0.08% of zirconium, 0.01% of phosphorus and the balance of copper under electromagnetic stirring to prepare molten copper liquid; (2) centrifugal casting is conducted, specifically, molten copper liquid is poured into an annular mold, a centrifugal machine is started, and an annular blank is obtained through cooling; (3) hot continuous rolling and on-line solid solution treatment are conducted, specifically, the outer surface of the centrifuged annular blank is turned, a square billet is obtained after ring unfolding, then hot continuous rolling and on-line solid solution heat treatment are conducted, and a coil wire is obtained; (4) cold rolling: after the surface of the coiled wire is peeled, cold rolling is performed to obtain a wire rod; and (5) aging heat treatment: carrying out vacuum aging strengthening to prepare a wire rod blank. The contact wire blank prepared through the preparation method is uniform in component and stable in performance, the produced contact wire finished product meets the performance requirement, and large-length uniformity and stability are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of contact wires and relates to a method for preparing a chromium-zirconium-copper contact wire blank. Background Art

[0002] The contact network is responsible for the important task of directly transmitting the electric energy obtained from the traction substation to the electric locomotive. Therefore, the quality and working condition of the contact network will directly affect the transportation capacity of the electrified railway. Since the contact network is set up in the open air without backup, and the load on the line moves and changes along the contact line with the operation of the electric locomotive, the following requirements are put forward for the contact network:

[0003] 1. To ensure the normal current supply of electric locomotives under high-speed operation and adverse climatic conditions, the contact network is required to have stability and sufficient elasticity in mechanical structure.

[0004] 2. Contact network equipment and parts should be interchangeable, have sufficient wear resistance and corrosion resistance, and extend the service life of the equipment as much as possible.

[0005] Copper-chromium-zirconium contact wire has the characteristics of high conductivity, high corrosion resistance, good durability, stable contact surface, etc. The finished product is required to be used for 1000-1500 meters, no joints are allowed, and the performance is uniform and stable. Therefore, the copper-chromium-zirconium contact wire meets the current railway use requirements and needs to have excellent mechanical properties and electrical conductivity, but strength and conductivity are a contradiction, and production is difficult. However, the existing blank preparation cannot meet the characteristics of large weight, long length, and uniform composition, and cannot well improve the material properties of copper-chromium-zirconium contact wire. Summary of the invention

[0006] In view of the deficiencies of the above-mentioned prior art, the present invention provides a method for preparing a chromium-zirconium-copper contact wire blank, which can meet the characteristics of uniform blank composition and stable performance. The specific technical scheme is as follows:

[0007] A method for preparing a chromium-zirconium-copper contact wire blank comprises the following steps:

[0008] (1) Vacuum induction melting: a raw material having an element composition ratio of 0.3-1.0% chromium, 0.05-0.15% zirconium, 0.005-0.02% phosphorus, and the remainder copper is subjected to vacuum induction melting under electromagnetic stirring to obtain molten copper liquid;

[0009] (2) Centrifugal casting: pouring molten copper into a ring-shaped mold, turning on the centrifuge, and cooling to obtain a ring-shaped blank;

[0010] (3) Hot rolling and online solution treatment: The outer surface of the centrifuged ring billet is turned, and the billet is made after ring expansion, and then hot rolling and online solution heat treatment are carried out to make coil wire;

[0011] (4) Cold rolling: After the surface of the coil is peeled, it is cold rolled to produce wire;

[0012] (5) Aging heat treatment: vacuum aging strengthening to produce wire blanks.

[0013] The present invention adopts vacuum induction melting to strictly control the element composition in the alloy, and can effectively remove the gas and non-metallic inclusions and non-ferrous metal impurities in the alloy. The addition of phosphorus is conducive to casting; it is carried out under highly clean conditions to avoid impurity pollution and harmful gas entry, and can prepare high-purity alloy materials; high-purity alloy materials have good corrosion resistance, oxidation resistance and stability. Centrifugal casting is fine in structure, free of defects such as shrinkage holes and pores, and ensures uniform composition and dense structure, so the mechanical properties are good; the centrifugal casting of the present invention does not require a core and a pouring system, which simplifies the casting process. Hot rolling and online solid solution crushing of grains realize fine grain strengthening, and at the same time, online solid solution strengthening is carried out by using the high temperature of hot rolling, which effectively combines fine grain strengthening and solid solution strengthening. Peeling and cold rolling provide a deformation amount of cross-sectional area>50%, which is energy storage for aging strengthening. While achieving aging strengthening, vacuum aging heat treatment ensures a smooth surface after heat treatment and a 100% yield rate. The contact wire finished product produced by the contact wire blank prepared by the preparation method of the present invention meets the performance requirements and achieves uniformity and stability over a large length.

[0014] Furthermore, in step (1), the smelting temperature is 1350-1380°C, the smelting time is 3.5-5 hours, and the vacuum degree is -0.1 MPa.

[0015] Furthermore, in the step (3), the deformation amount of the hot rolling is 95-97%, the heating temperature of the hot rolling and the online solution heat treatment is 960-980°C, and the heating time is 4-6h.

[0016] Furthermore, in the step (3), the hot-rolled coil is put into water for solid solution treatment at a temperature of more than 850°C.

[0017] Furthermore, in the step (4), the deformation amount of cold rolling is 55-65%.

[0018] Furthermore, in the step (5), the temperature of the vacuum aging heat treatment is 420-450°C, the treatment time is 4-6h, and the vacuum degree is -0.1MPa.

[0019] The beneficial effects of the present invention are:

[0020] The contact wire blank prepared by the preparation method of the present invention has uniform composition and stable performance. The produced contact wire finished product meets the performance requirements and achieves uniformity and stability over a large length. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the metallographic diagram of the product after hot rolling in Example 1 of the present invention. DETAILED DESCRIPTION

[0022] The principles and features of the present invention are described below in conjunction with embodiments. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0023] Embodiment 1:

[0024] A method for preparing a chromium-zirconium-copper contact wire blank comprises the following steps:

[0025] (1) Vacuum induction melting: The raw materials with the element composition ratio of 0.8% chromium, 0.08% zirconium, 0.01% phosphorus and the balance copper are subjected to vacuum induction melting in a vacuum induction melting furnace under electromagnetic stirring at a melting temperature of 1365±15°C and a vacuum degree of -0.1MPa for 4 hours to ensure that the alloy elements are fully dissolved to obtain molten copper liquid;

[0026] (2) Centrifugal casting: Pour the molten copper into a ring-shaped mold with an outer diameter of 3.5 meters, turn on the centrifuge at 400-600 rpm, and water-cool to obtain a ring-shaped billet with an outer diameter of 3.5 meters, a cross-section of 180×180 mm, and a tolerance of ±3 mm;

[0027] (3) Hot rolling and online solution treatment: The outer surface of the centrifuged ring billet was turned, and the ring was expanded to obtain a square billet with a cross section of 160×160 mm and a length of 11 meters. The billet was heated at 970±10℃ for 5 hours, and then hot rolled and solution treated online to obtain The coil line;

[0028] (4) Cold rolling: After the surface is peeled on a centerless lathe, it is cold rolled with a deformation of 60% to produce a wire with a diameter of 20 mm;

[0029] (5) Vacuum aging heat treatment: vacuum aging strengthening is performed at 435±15°C and a vacuum degree of -0.1 MPa for 5 h to obtain the wire blank.

[0030] The metallographic image of the product after hot rolling in this embodiment is as follows Figure 1 As shown, the grains are refined, <50um, and the alloy elements are evenly distributed; the wire blank prepared in this embodiment is pulled to a contact line of 150mm 2 Specifications meet the performance standard requirements, the length can meet 1000-1500 meters, there is no welding point in the middle, and the performance is uniform. The conductivity and tensile strength of the contact wire prepared in this embodiment are shown in Table 1:

[0031] Table 1 Electrical conductivity and tensile strength of the contact wire obtained in Example 1

[0032] <![CDATA[Specification mm 2 > Electrical conductivity %IACS Tensile strength MPa 150 83.2 571

[0033] Embodiment 2:

[0034] A method for preparing a chromium-zirconium-copper contact wire blank comprises the following steps:

[0035] (1) Vacuum induction melting: The raw materials with the element composition ratio of 0.5% chromium, 0.1% zirconium, 0.015% phosphorus and the balance copper are placed in a vacuum induction melting furnace and subjected to vacuum induction melting under electromagnetic stirring at a melting temperature of 1365±15°C and a vacuum degree of -0.1MPa for 4 hours to ensure that the alloy elements are fully dissolved to obtain molten copper liquid;

[0036] (2) Centrifugal casting: Pour the molten copper into a ring-shaped mold with an outer diameter of 3.5 meters, turn on the centrifuge at 400-600 rpm, and water-cool to obtain a ring-shaped billet with an outer diameter of 3.5 meters, a cross-section of 180×180 mm, and a tolerance of ±3 mm;

[0037] (3) Hot rolling and online solution treatment: The outer surface of the centrifuged ring billet was turned, and the ring was expanded to obtain a square billet with a cross section of 160×160 mm and a length of 11 meters. The billet was heated at 970±10℃ for 5 hours, and then hot rolled and solution treated online to obtain The coil line;

[0038] (4) Cold rolling: After the surface is peeled on a centerless lathe, it is cold rolled with a deformation of 60% to produce a wire with a diameter of 20 mm;

[0039] (5) Vacuum aging heat treatment: vacuum aging strengthening at 435±15℃, vacuum degree of -0.1MPa, 5h to obtain wire blank.

[0040] The wire blank prepared in this embodiment is pulled to a contact line of 150 mm. 2 Specifications meet the performance standard requirements, the length can meet 1000-1500 meters, there is no welding point in the middle, and the performance is uniform. The conductivity and tensile strength of the contact wire prepared in this embodiment are shown in Table 2:

[0041] Table 2 Electrical conductivity and tensile strength of the contact wire obtained in Example 2

[0042] <![CDATA[Specification mm 2 > Electrical conductivity %IACS Tensile strength MPa 150 82.5 575

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a chromium-zirconium-copper contact wire blank, characterized in that: The steps include: (1) Vacuum induction melting: a raw material having an element composition ratio of 0.8% chromium, 0.08% zirconium, 0.01% phosphorus and the remainder copper is subjected to vacuum induction melting under electromagnetic stirring to obtain molten copper liquid; (2) Centrifugal casting: pouring molten copper into a ring-shaped mold, turning on the centrifuge, and cooling to obtain a ring-shaped blank; (3) Hot rolling and online solution treatment: The outer surface of the centrifuged ring billet is turned, and the billet is made after ring expansion, and then hot rolling and online solution heat treatment are carried out to make coil wire; (4) Cold rolling: After the surface of the coil is peeled, it is cold rolled to produce wire; (5) Aging heat treatment: vacuum aging strengthening to produce wire blanks.

2. The method for preparing the chromium-zirconium-copper contact wire blank according to claim 1, characterized in that: In the step (1), the smelting temperature is 1350-1380° C., the smelting time is 3.5-5 hours, the vacuum degree is -0.1 MPa, and electromagnetic stirring is performed during the process.

3. The method for preparing the chromium-zirconium-copper contact wire blank according to claim 1, characterized in that: In the step (3), the deformation amount of hot rolling is 95-97%, the heating temperature of hot rolling and online solution heat treatment is 960-980°C, and the heating time is 4-6h to obtain a coiled wire.

4. The method for preparing the chromium-zirconium-copper contact wire blank according to claim 3, characterized in that: In the step (3), the hot-rolled coil is placed in water for solid solution treatment at a temperature greater than 850°C.

5. The method for preparing the chromium-zirconium-copper contact wire blank according to claim 1, characterized in that: In the step (4), the deformation amount of cold rolling is 55-65%.

6. The method for preparing the chromium-zirconium-copper contact wire blank according to claim 1, characterized in that: In the step (5), the temperature of the vacuum aging heat treatment is 420-450° C., the treatment time is 4-6 hours, and the vacuum degree is -0.1 MPa.

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