Surface alloyed wire manufacturing process, wire and apparatus for making same

Abstract

The application discloses a surface alloying metal wire manufacturing process, comprising the following steps: S1, selecting a raw material thick wire as an inner core matrix of the metal wire; the raw material thick wire is a chromium family element metal or an alloy with the chromium family element metal as a main component; S2, first surface treatment; S3, covering at least one ductile metal layer on the surface of the raw material thick wire, and the elongation of the ductile metal material is greater than or equal to 10%; S4, heat diffusion and fusion of the metal layer on the surface of the raw material thick wire into a uniform layer or several layers of metal layers with a gradient at a temperature of 500 DEG C to 1000 DEG C; S5, second surface treatment; S6, attaching lubricating liquid to the surface of the semi-finished metal wire, and performing cold drawing to deform the semi-finished metal wire into a metal wire with a target wire diameter. The application also discloses a metal wire prepared by the process and a preparation device for realizing the manufacturing process. Through solid-liquid two-layer lubrication, the application can realize more efficient and uniform heat dissipation, draw thinner and higher-strength metal wires, and increase the fatigue life of the metal wire.

Description

Technical Field

[0001] This invention relates to the field of metal wire processing technology, specifically to a surface alloying metal wire manufacturing process, a metal wire, and a preparation apparatus thereof. Background Technology

[0002] Currently, most metal wires are made of materials such as iron wire, copper wire, stainless steel wire, manganese steel wire, and aluminum wire. With the development of industry, high-strength and ultra-fine metal wires are required in certain application environments (such as electrical discharge cutting and heating elements), and existing conventional metal wires can hardly meet the needs.

[0003] Chromium group elements, or group VIB elements of the periodic table, include chromium, molybdenum, and tungsten. They are characterized by high hardness and high melting points. In particular, molybdenum and tungsten, or their alloys, exhibit excellent stability and high strength. The current main process for producing such fine wires is as follows: raw material coarse wire, annealing, coarse drawing, annealing, fine drawing, fine wire. For some even finer specifications, an alkaline electrolytic diameter reduction process is added after fine drawing to clean the surface and further etch it to achieve an even smaller wire diameter.

[0004] The deformation processing of chromium group elements and their alloys can be divided into two main categories: hot deformation processing and cold deformation processing. Hot deformation processing involves plastic deformation above the metal's recrystallization temperature. Common methods include forging, hot bending of profiles, hot pressing, and hot drawing. In hot drawing, relatively small pressure is applied to reach the material's yield point, causing plastic deformation and releasing primary or processing stresses, thus extending the material into thinner and longer wires with a low risk of wire breakage. In contrast, cold deformation processing involves plastic deformation below the recrystallization temperature. During cold drawing, the material is subjected to greater shear, pressure, bending, impact, and frictional forces, resulting in a denser crystalline structure, higher mechanical strength, surface hardness, and wear resistance. However, due to the high hardness of chromium group elements, traditional cold drawing processes lead to excessive die wear and a high wire breakage rate, hindering mass production.

[0005] For chromium group elements and their alloy wires, the current mainstream drawing process involves coating the raw wire with graphite emulsion as a solid lubricant, and then stretching and deforming it step by step through multiple drawing dies under heating conditions to become a finer metal wire. For example, Chinese invention patent CN201410075866 discloses an electrolytic machining method for preparing cylindrical micro tungsten wire electrodes by electrolyte-assisted impact, including the following steps: placing the tungsten wire electrode preparation material into a fixture and fixing it; inputting processing data according to the size requirements of the prepared cylindrical micro tungsten wire electrode and preparing for processing; before processing, connecting the pressure system power supply so that the electrolyte is pushed upwards onto the preparation material through the nozzle system by the action of the pressure pump; then connecting the machine tool power supply, the preparation material rotates under the drive of the motor, and the stainless steel plate electrolytically processes the preparation material. At the same time, the electrolyte impacts the electrolytic processing area downwards along the rotating preparation material and flows back into the electrolyte tank, thereby realizing the circulation of the electrolyte. Using electrolyte-assisted impact to prepare cylindrical micro tungsten wire electrodes can improve the efficiency and quality of electrolytic machining, avoid the formation of a "spindle" structure of the tungsten wire electrode during processing, and thus obtain a cylindrical micro tungsten wire electrode with a uniform diameter. Although this invention enables the processing of fine tungsten wires and makes the electrode wires more regular in shape, it is only suitable for laboratory-scale preparation under conditions of small deformation and is not suitable for industrial-scale production.

[0006] Chinese invention patent CN111185487 discloses a drawing process for wire-cut molybdenum wire, which involves heating only the die and not the wire itself. The die heating temperature for the first pass is 350℃~300℃, preferably 320℃. As processing progresses, the die heating temperature gradually decreases by 15℃. When the wire diameter is <0.25m, co-heating of the die is not required during processing. The strength and fatigue resistance of the molybdenum wire prepared by this hot drawing process still have room for improvement, and it consumes a significant amount of energy.

[0007] Chinese invention patent CN101368287 discloses a multi-step continuous processing method for ultrafine molybdenum wire. The method includes the following steps: (a) multiple electrolytic cells containing NaOH solution are arranged horizontally side-by-side and uniformly, with the cells externally protected by hydrogen purging, and adjacent electrolytic cells having opposite polarities; (b) high-temperature corrosion for diameter reduction, stress-relieving annealing, and straightening: after straightening the molybdenum wire to be processed, it is sequentially passed horizontally through multiple electrolytic cells at a traveling speed of V=1~50m / min, and heated to a temperature of 800~1100℃. This invention involves complex steps, requires corrosion for diameter reduction to obtain finer molybdenum wire, and has high energy consumption.

[0008] Chinese invention patent CN109622641 discloses a high-efficiency stainless steel wire drawing process. The process includes the following steps: preparation of stainless steel material, preheating of the drawing die, and fixing the heating power. The wire drawing process begins with the addition of lubricant, first wire drawing, first annealing, second wire drawing, second annealing, final wire drawing, application of protective oil, winding and storage, inspection and warehousing, and regular spot checks. The beneficial effects of this invention are: by setting up the first annealing, second annealing, application of protective oil, and regular spot checks, this annealing treatment can effectively improve the strength and toughness of the stainless steel wire, thereby extending its service life. However, this invention involves complex processes, requiring multiple heat treatments and hot drawing, and has high energy consumption.

[0009] Analysis of existing research shows that existing drawing processes for chromium group metals and their alloys are difficult to achieve higher compression ratios and consume a lot of energy. How to prepare fine wires with higher strength and fatigue resistance is a common technical problem in this field. Summary of the Invention

[0010] One objective of this invention is to provide a manufacturing process and a metal wire for surface alloying to improve the strength, hardness, and fineness of the metal wire. A second objective is to provide an apparatus for preparing surface alloyed metal wire, thereby achieving continuous and automated production of the metal wire. To achieve the above objectives, this invention adopts the following technical solution: This invention discloses a manufacturing process for surface-alloyed metal wires, comprising the following steps: S1. Select raw material coarse wire as the inner core matrix of the metal wire; the raw material coarse wire is a chromium group metal or an alloy with chromium group metal as the main component.

[0011] S2. Perform the first surface treatment on the surface of the raw material coarse filaments.

[0012] S3. Cover the surface of the raw material coarse wire with at least one layer of ductile metal layer, wherein the ductile metal layer is made of ductile metal material and the elongation of the ductile metal material is ≥10%.

[0013] S4. At a temperature of 500℃~1000℃, the ductile metal layer on the surface of the raw material coarse wire is fused into a uniform single layer or several gradient metal layers to obtain a semi-finished metal wire. This step is an alloying step, which uses high temperature to diffuse and fuse the outer ductile metal layer (i.e., equivalent to a solid metal lubricating layer) inward into a uniform or gradient alloy layer, and further enhances the bonding force between the solid metal lubricating layer and the inner core matrix.

[0014] S5. Perform a second surface treatment on the surface of the semi-finished metal wire obtained in step S4.

[0015] S6. A lubricant is applied to the surface of the semi-finished metal wire, and then it is cold-drawn at room temperature to deform the semi-finished metal wire into a wire of the target diameter. Because the lubricant on the metal layer surface is liquid lubricant, while the ductile metal material on the surface of the raw wire becomes solid lubricant, the raw wire is drawn and deformed into a wire of the target diameter under the combined effect of solid and liquid lubrication. Through these two lubrication layers (solid and liquid), the cold drawing forming effect of chromium group metals or alloys with chromium group metals as the main component is achieved (chromium group metals or alloys with chromium group metals as the main component are difficult to cold draw without lubrication). The alloying speed and the sublimation and dissipation of the coating metal are balanced and controlled by adjusting the wire speed and temperature or current.

[0016] Preferably, the first surface treatment in step S2 includes: S21. Degreasing: The raw material coarse filaments are passed through an alkaline degreasing agent to remove surface oil and oxides; then washed with water to remove any residual alkaline degreasing agent.

[0017] S22. Pickling: The raw filaments are passed through a pickling solution to neutralize contaminants on the surface of the raw filaments that could not be removed by the alkaline degreasing agent; oxides are removed and the surface is activated; and residual pickling solution is washed away from the surface.

[0018] Preferably, in step S4, an inert gas or a reducing protective gas is used for heating, and the heating method is one of induction heating, resistance heating, flame burning, or high-temperature furnace heating.

[0019] The second surface treatment in step S5 includes: S51. Secondary pickling: The metal layer surface of the raw material coarse wire is pickled to remove the metal oxides on the surface; water washing: the residual pickling solution on the surface is washed away.

[0020] Furthermore, the raw material filament is tungsten metal or tungsten alloy; the ductile metal material is one or more of the metal elements copper, tin, zinc, cobalt, nickel, and manganese.

[0021] Preferably, in step S3, a ductile metal layer is electroplated on the surface of the raw material coarse wire. The ductile metal layer includes an intermediate metal layer and one or more outer metal layers, specifically including the following steps: S31. Pre-plating: Pre-plating an intermediate metal layer on the surface of the raw material coarse wire, wherein the thickness of the intermediate metal layer H1≤2μm; washing away the residual pre-plating solution on the surface.

[0022] S32. Electroplating, wherein one or more outer metal layers are electroplated on a pre-plated intermediate metal layer, wherein the thickness of each outer metal layer is less than or equal to 20 μm.

[0023] In another embodiment, in step S3, a ductile metal layer is hot-plated on the surface of the raw material coarse wire. The ductile metal material is heated and melted at 500°C to 1200°C to form a hot-plating solution. The inner core substrate is passed through the hot-plating solution to form a ductile metal layer on the surface of the inner core substrate.

[0024] The intermediate metal layer is nickel, cobalt, manganese, or their alloys. Two outer metal layers are electroplated on the pre-plated intermediate metal layer, with the first outer metal layer being copper or a copper alloy. After electroplating, the residual copper solution on the surface is washed away. Then, a second outer metal layer is electroplated, which is zinc, tin, or their alloys. After electroplating, the residual solution on the surface is washed away.

[0025] S52. Drying, drying the surface water.

[0026] In step S6, cold drawing is performed multiple times, with the deformation of the metal wire set to 1% to 10% for each drawing. Depending on the wire diameter requirements of the specific target product, 5 to 50 cold drawing passes can be performed.

[0027] Preferably, the lubricant is a water-based lubricant; depending on the actual drawing situation, if the die wear or wire breakage rate is too high, the semi-finished metal wire after cold drawing can be annealed before entering the next drawing.

[0028] The present invention also discloses a metal wire, which is manufactured using the above-mentioned surface alloying metal wire manufacturing process, including an inner core substrate and one or more metal layers covering the inner core substrate. The inner core substrate is made of chromium group metals or an alloy with chromium group metals as the main component.

[0029] The present invention also discloses a surface alloyed metal wire preparation device, comprising a primary wire feeding device, a primary surface treatment device, a metal plating production line, a high-temperature heating device, a secondary surface treatment device, a multi-die cold drawing device, and a finished wire take-up device arranged sequentially. The metal plating production line is an electroplating production line or a hot-dip galvanizing production line. The multi-die cold drawing device includes a lubricating fluid tank and multiple drawing dies. The lubricating fluid tank is used to hold lubricating fluid, and the drawing dies are disposed in the lubricating fluid tank.

[0030] The raw material filament is drawn by the primary wire feeding device to the primary surface treatment device for the first surface treatment, and then drawn to the metal plating production line for electroplating or hot-dip plating at least one layer of ductile metal layer; the raw material filament with the ductile metal layer is thermally diffused in a high-temperature heating device to form a semi-finished metal wire, the high-temperature heating device is connected to a protective gas supply pipe, the thermally diffused semi-finished metal wire is drawn to the secondary surface treatment device for the second surface treatment, and then drawn into a multi-die cold drawing device for multiple cold drawing to form a finished metal wire, and finally wound onto the finished product take-up device.

[0031] Preferably, it also includes a heat treatment device, wherein the semi-finished metal wire is transferred to the heat treatment device for heat treatment after passing through the multi-die cold drawing device, and then returns to the multi-die cold drawing device for cold drawing.

[0032] Furthermore, the first surface treatment device includes a degreasing tank, a degreasing water washing tank, an acid pickling tank, and an acid post-acid washing tank connected in sequence; the second surface treatment device includes a secondary acid pickling tank, a secondary acid post-acid washing tank, and a dryer connected in sequence; the electroplating production line includes a pre-plating tank, multiple electroplating tanks, and multiple water washing tanks, with the water washing tanks located at the end of the pre-plating tank and each electroplating tank.

[0033] Preferably, the degreasing tank includes a main degreasing tank, a pump, and a sub-degreasing tank located above the main degreasing tank. Two first partitions are provided in the middle of the sub-degreasing tank, dividing it into a front, middle, and rear section. First winding reels are provided in the front and rear sections, driven by a first rotary motor installed at the bottom of the sub-degreasing tank. Several electrolytic cells for holding electrolyte are installed in the middle of the sub-degreasing tank. Electrode plates are installed in the middle of each electrolytic cell, connected to an external circuit, and their polarity is controlled by switching via the external circuit. A liquid outlet is provided at the bottom of the middle section of the sub-degreasing tank, communicating with the main degreasing tank. First slits for metal wires to pass through are provided on both sides of the sub-degreasing tank, the partitions, and both sides of the electrolytic cells. The pump is installed on the main tank and is used to transfer liquid from the main tank to the electrolytic cells.

[0034] Preferably, the pre-plating tank and the electroplating tank are provided with second winding wheels at both ends, which are driven by a second rotary motor. The ends of both the pre-plating tank and the electroplating tank are provided with second slits for metal wires to pass through. The second winding wheels are located in the middle of the width of the pre-plating tank or the electroplating tank, and the second slits are located at the edge of the width. Multiple partition plates are provided inside the washing tank. Third slits for metal wires to pass through are provided at the ends of the washing tank and above the partition plates. The third slits are arranged alternately, and the second slit at the tail end of the pre-plating tank or the electroplating tank corresponds to the third slit at the end of the adjacent washing tank, and the third slit at the tail end of the washing tank corresponds to the second slit at the front end of the adjacent electroplating tank.

[0035] After adopting the above technical solution, the present invention has the following effects: 1. This invention uses chromium group metals or alloys with chromium group metals as the main components as the core matrix of the metal wire, which has the characteristics of high hardness and high melting point. A solid metal layer (equivalent to a solid lubricating layer) is formed by covering the surface of the core matrix, and then a liquid lubricating layer is formed by attaching a lubricating liquid to the surface of the metal layer, thus forming a solid-liquid dual-layer lubricating layer. The solid lubricating layer can prevent the core material from contacting and engaging with the die surface during cold drawing, allowing pressure to be uniformly conducted radially and causing deformation of the core matrix. The generated heat is efficiently carried away by the lubricating liquid. The resulting metal wire has higher strength and higher surface hardness than existing hot drawing methods at the same compression ratio. This invention has a stable process and low manufacturing cost. Through the solid-liquid dual-layer lubricating layer, more efficient and uniform heat dissipation can be achieved, avoiding localized micro-area high temperatures, preventing the formation of carbide hard spots by tribochemical reactions, reducing surface defects, and increasing the fatigue life of the metal wire.

[0036] 2. This invention can draw ultra-fine metal wires with a diameter of less than 35μm and a strength of up to 8000MPa, which can be used to manufacture diamond wire saws or electrical discharge cutting, filaments, heating elements, etc.

[0037] 3. This invention utilizes high temperature to achieve uniform diffusion and fusion of the solid-phase metal layer, further enhancing the bonding force between the metal layer and the inner core substrate. Thermal diffusion eliminates the original stress of the inner core substrate or the stress generated during electroplating, allowing subsequent cold drawing processes to be carried out stably with low mold loss.

[0038] 4. The ultrafine metal wire obtained by the present invention has a smooth surface with metallic luster and good conductivity. It can be produced without special treatment when further electroplating to manufacture diamond wire and other products. In contrast, conventional hot drawing methods require further alkaline electrolysis to purify the surface due to the residual graphite and oxide layers on the surface.

[0039] 5. The preparation device of this invention realizes continuous automated production of metal wires, with no interference between each process, thus improving production efficiency.

[0040] 6. The degreasing tank in the device of the present invention is ingeniously designed. The electrode plates are connected to the external circuit. The polarity of the electrode plates is set to an odd number. By fixing the polarity of the last electrode, the remaining electrode plates are switched and controlled by the external circuit to achieve automatic and efficient electrolytic degreasing without conductive wheels, while making maintenance simpler. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the structure of the metal wire obtained in Embodiment 1 of the present invention.

[0042] Figure 2 This is a schematic diagram of the structure of the metal wire obtained in Embodiment 2 of the present invention.

[0043] Figure 3This is a schematic diagram of the connection of the preparation device of the present invention (from the primary wire feeding device to the primary wire taking-up device, electroplating production line).

[0044] Figure 4 This is a schematic diagram of the connection of the preparation device of the present invention (from the secondary wire feeding device to the secondary wire taking-up device).

[0045] Figure 5 This is a schematic diagram of the connection of the preparation device of the present invention (from the three-stage wire feeding device to the finished product wire taking-up device).

[0046] Figure 6 This is a schematic diagram of the connection of the preparation device of the present invention (from the primary wire feeding device to the primary wire taking-up device, hot-dip galvanizing production line).

[0047] Figure 7 This is a schematic diagram of the structure of the first surface treatment device and electroplating production line of the present invention.

[0048] Figure 8 This is a schematic diagram of the degreasing tank of the present invention.

[0049] Figure 9 This is a three-dimensional cross-sectional schematic diagram of the de-grooving sub-groove of the present invention.

[0050] Figure 10 This is a schematic diagram of the electroplating production line of the present invention.

[0051] Figure 11 yes Figure 10 A top-down view.

[0052] Explanation of key component symbols: 1: Inner core substrate; 2: Intermediate metal layer; 3: First outer metal layer; 4: Second outer metal layer; 41: Hot-dip galvanized metal layer; 5: Primary unwinding device; 6: First surface treatment device; 61: Degreasing tank; 611: Degreasing master tank; 612: Degreasing sub-tank; 613: First partition plate; 614: First winding reel; 615: First rotary motor; 616: Electrolytic cell; 617: Electrode plate; 618: Liquid outlet; 619: First slit; 62: Degreasing water washing tank; 63: Pickling tank; 64: Post-acid washing tank. 7: Electroplating production line; 71: Pre-plating tank; 72: Electroplating tank; 73: Washing tank; 74: Second winding wheel; 75: Second slit; 76: Second partition; 77: Third slit; 8: First winding device; 9: Second unwinding device; 10: High-temperature heating device; 11: Second surface treatment device; 12: Second winding device; 13: Third unwinding device; 14: Multi-die cold drawing device; 15: Heat treatment device; 16: Finished product winding device; 17: Raw material coarse wire; 18: Hot-dip galvanizing production line; 19: Metal wire. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0054] Example 1 This embodiment discloses a manufacturing process for surface-alloyed metal wire, including the following steps: S1. Select the inner core substrate Chromium group metals or alloys with chromium group metals as the main components are selected as the core matrix of the metal wire. The core matrix selected in this step is the raw material coarse wire with a diameter of 0.1 to 1 mm.

[0055] To improve the strength and performance of the metal wire, this invention selects chromium group metals or alloys with chromium group metals as the core matrix material. Specifically, the chromium group metals are chromium, molybdenum, or tungsten. Alloys with chromium group metals as the main component include chromium alloys, molybdenum alloys, or tungsten alloys, including binary or multi-component alloys.

[0056] S2. First surface treatment The surface of the raw material coarse filaments undergoes a first surface treatment. This first surface treatment includes: S21. Degreasing The raw filaments are passed through an alkaline degreasing agent to remove oil, oxides, and other foreign matter from their surface. This can be done by simple soaking or electrolytic degreasing. The alkaline degreasing agent is an aqueous solution primarily composed of alkaline cleaning agents. Through saponification and emulsification, it removes oil from the surface of the inner core substrate. After degreasing, the surface is washed with water to remove any residual alkaline degreasing agent.

[0057] S22. Pickling The raw filaments are passed through an acid pickling solution to neutralize contaminants on the surface that could not be removed by the alkaline degreasing agent. The acid pickling solution is generally a mixture of various acids, mainly sulfuric acid, nitric acid, hydrofluoric acid, and certain organic acids. These mixed acids have certain corrosive and complexing properties, which can remove oxides and contaminants from the surface.

[0058] After pickling, rinse with water to remove any residual pickling solution from the surface. This is to prevent the mixed acid from further corroding the inner core substrate or contaminating subsequent plating solutions.

[0059] S3. Electroplating At least one ductile metal layer is coated onto the surface of the raw material coarse wire. The ductile metal layer is made of a ductile metal material with an elongation ≥10%. The ductile metal material is one or more of the metal elements copper, tin, zinc, cobalt, nickel, and manganese. The ductile metal layer includes an intermediate metal layer and one or more outer metal layers, specifically including the following steps: S31. Pre-plating: A layer of intermediate metal is pre-plated onto the surface of the raw material coarse wire. The thickness of the intermediate metal layer, H1, is ≤ 2 μm. After pre-plating, the residual pre-plating solution on the surface is washed away.

[0060] The intermediate metal layer is one or more of the following metal elements: copper, tin, zinc, cobalt, nickel, and manganese. During pre-plating, the raw material wire is simply connected to the cathode of a DC power supply and quickly passed through a pre-plating solution containing the corresponding metal ions to form an intermediate metal layer on the surface of the raw material wire. The purpose of pre-plating the intermediate metal layer is to prevent the inner core substrate from diffusing into the outer electroplated metal layer and to improve adhesion.

[0061] S32. Electroplated metal layer One or more outer metal layers are electroplated on the pre-plated intermediate metal layer, each outer metal layer having a thickness of less than or equal to 20 μm. The material of the outer metal layer is one or more of the following metallic elements: copper, tin, zinc, cobalt, nickel, and manganese.

[0062] In this embodiment, a first outer metal layer and a second outer metal layer are sequentially electroplated outside the intermediate metal layer. The first outer metal layer is copper, and the second outer metal layer is zinc or tin. Copper, zinc, and tin are all highly ductile metals with an elongation of ≥10%, and copper exhibits better alloying effects when fused with zinc or tin in subsequent thermal diffusion processes. Their high ductility is utilized to deform the surface plating and further conduct pressure to the inner core substrate for subsequent cold drawing.

[0063] Each electroplating process involves rinsing with water before applying the next layer to remove any residual electroplating solution from the surface, thus preventing contamination of the solution in subsequent electroplating processes and avoiding potential corrosion or discoloration.

[0064] S4. Alloying At temperatures ranging from 500℃ to 1000℃, the ductile metal layer on the surface of the inner core substrate is thermally diffused and fused into a single uniform layer or several gradient metal layers, resulting in a semi-finished metal wire, thus achieving alloying. This step utilizes high temperature to ensure uniform diffusion and fusion of the solid-phase metal layer, further enhancing the bonding force between the solid-phase metal layer (equivalent to a solid-phase lubricating layer) and the inner core substrate. Thermal diffusion also eliminates the original stress in the inner core substrate or the stress generated during electroplating, allowing for stable and low-die-loss operation in subsequent cold drawing processes.

[0065] In this embodiment, since there is an intermediate metal layer, a first outer metal layer and a second outer metal layer, they fuse into a gradient three-layer metal layer after thermal diffusion.

[0066] Methods of heat diffusion include induction heating (medium-frequency or high-frequency induction heating), resistance heating, flame burning, and high-temperature furnace heating. To reduce metal volatilization or plating oxidation at high temperatures, inert gases or reducing protective gases are used for heating. Reducing protective gases include hydrogen and ammonia, while inert gases include nitrogen and argon.

[0067] S5. Perform a second surface treatment on the surface of the semi-finished metal wire obtained in step S4.

[0068] The second surface treatment includes: S51. Secondary pickling: The surface of the original semi-finished metal wire is pickled to remove surface metal oxides. After the secondary pickling, it is washed with water to remove residual pickling solution and avoid uneven corrosion.

[0069] S52. Dry the surface to remove moisture. This prevents oxidation or corrosion of the surface metal layer caused by moisture.

[0070] S6. Cold drawing Lubricant is applied to the surface of the metal layer, and cold drawing is performed at room temperature. Under the combined effect of the metal layer and the lubricant, the raw material coarse wire is stretched and deformed into a metal wire of the target diameter.

[0071] Cold drawing is performed using a multi-die cold drawing device. Methods for applying lubricant to the surface include: (1) Immerse multiple wire drawing die holes in lubricating liquid, and then immerse the raw material coarse wire in lubricating liquid in the same way, so that the surface of its metal layer is covered with lubricating liquid.

[0072] (2) Lubricating liquid is sprayed onto the metal layer surface of the raw material coarse wire through a spraying device.

[0073] (3) Apply lubricant to the metal layer surface of the raw material coarse wire using a coating equipment.

[0074] Lubricants include water-based lubricants, oil-based lubricants, and emulsified lubricants. In order to efficiently remove the heat of cold drawing by the lubricant, water-based lubricants are preferred. Water-based lubricants have a higher specific heat, which can quickly remove the heat during the drawing process, avoid localized high temperatures, prevent the formation of carbide hard spots by tribochemical reactions, and reduce surface defects.

[0075] By using a multi-die cold drawing device, different compression rates can be set for each pass. The raw material filament is drawn and compressed step by step through various drawing dies using traction rollers or traction wheels to obtain the final ultrafine metal wire. For example, by setting the deformation degree of the metal wire in each drawing to 1-3%, 5-50 cold drawing passes can yield ultrafine metal wires with a target wire diameter of less than 35μm.

[0076] Depending on the target product's wire diameter requirements and actual drawing conditions, if die wear or wire breakage rate is too high, the semi-finished metal wire after cold drawing can be annealed to reduce work hardening and soften the wire, thus facilitating subsequent drawing. No further annealing is performed after the final cold drawing.

[0077] The ultra-fine metal wires obtained after drawing are finally wound onto a wheel and packaged to form the finished product.

[0078] Example 2 This embodiment discloses a manufacturing process for surface alloyed metal wires. The difference from Embodiment 1 is that step S3 in this embodiment uses a hot-dip galvanizing process.

[0079] Steps S1-S2 are the same as in Example 1.

[0080] S3. Hot-dip galvanizing A metal layer is hot-dip galvanized onto the surface of the inner core substrate. The specified metal is melted at 500℃~1200℃ to form a hot-dip galvanizing solution. The inner core substrate is then passed through this solution, allowing the metal layer to form on its surface. The hot-dip galvanizing process exhibits more stable quality when a protective gas is present. Therefore, hot-dip galvanizing can be performed in an environment filled with a protective gas.

[0081] This embodiment uses a hot-dip galvanizing process, which eliminates the need for electroplating, pre-plating, and corresponding water washing, making it simpler than the process in Embodiment 1.

[0082] Example 3 This embodiment discloses a metal wire, including an inner core matrix and one or more metal layers covering the inner core matrix. The inner core matrix is ​​made of chromium group metals or an alloy with chromium group metals as the main component.

[0083] like Figure 1 As shown, the metal wire produced using the manufacturing process of Example 1 has an inner core substrate 1 of tungsten or a tungsten alloy, an intermediate metal layer 2 of nickel, cobalt, manganese, or their alloys, a first outer metal layer 3 of copper, and a second outer metal layer 4 of zinc or tin. The intermediate metal layer 2 is partially or completely fused with the first metal layer 3, and the first metal layer 3 is partially fused with the second metal layer 4.

[0084] like Figure 2 As shown, the metal wire produced using the manufacturing process of Example 1 has an inner core substrate 1 surrounded by a hot-dip galvanized metal layer. The hot-dip galvanized metal layer 41 can be a mixed metal of copper and zinc, or a mixed metal layer of manganese alloy or copper alloy, etc.

[0085] Example 4 This embodiment discloses a surface alloying metal wire preparation apparatus for implementing the manufacturing process of the present invention and producing the metal wire of the present invention.

[0086] like Figures 3-5As shown, the preparation apparatus of the present invention includes, in sequence, a primary wire feeding device 5, a primary surface treatment device 6, a metal plating production line, a primary wire take-up device 8, a secondary wire feeding device 9, a high-temperature heating device 10, a secondary surface treatment device 11, a secondary wire take-up device 12, a tertiary wire feeding device 13, a multi-die cold drawing device 14, a heat treatment device 15, and a finished product take-up device 16. The metal plating production line is either an electroplating production line 7 or a hot-dip galvanizing production line 18 (e.g.,...). Figure 6 (As shown). The multi-die cold drawing device 14 includes a lubricating fluid tank and multiple drawing dies. The lubricating fluid tank is used to hold lubricating fluid, and the drawing dies are arranged inside the lubricating fluid tank.

[0087] like Figure 3 As shown, the raw material filament is drawn by the primary unwinding device 5 to the primary surface treatment device 6 for the first surface treatment. The primary surface treatment device 6 includes a degreasing tank 61, a degreasing water washing tank 62, an acid pickling tank 63, and a post-acid water washing tank 64 connected in sequence. Then, it is drawn to the metal plating production line to electroplate or hot-dip galvanize at least one layer of ductile metal, and then wound up on the primary winding device 8.

[0088] like Figure 8 , Figure 9 As shown, the degreasing tank 61 includes a main degreasing tank 611, a pump (not shown), and a sub-degreasing tank 612 located above the main degreasing tank 611. Two first partitions 613 are provided in the middle of the sub-degreasing tank 612, dividing it into a front, middle, and rear section. First winding wheels 614 are provided in the front and rear sections, driven by a first rotary motor 615, which is mounted at the bottom of the sub-degreasing tank 612.

[0089] Several electrolytic cells 616 for holding electrolyte are installed in the middle of the degreasing tank 612. Electrode plates 617 are installed in the middle of the electrolytic cells 616. The electrode plates 617 are connected to an external circuit. The number of electrode plates 617 is odd. The polarity of the last electrode plate 617 is controlled by switching via an external circuit (e.g., by setting a timer to switch). Setting the number of electrode plates 617 to odd and the last electrode having a fixed polarity. In this embodiment, three electrode plates 617 are provided, and the polarity can be set to +–– or –+–. Switching the polarity of the first two electrode plates achieves electrolytic degreasing, removing grease and other contaminants from the surface of the raw material filaments. The structure of this invention eliminates the traditional method of electrolysis by setting conductive wheels, allowing the first and second winding wheels of this invention to be made of alkali-resistant and rust-resistant plastic material, improving service life and reducing maintenance costs.

[0090] A liquid outlet 618 is provided at the bottom center of the degreasing sub-tank 612, which communicates with the degreasing main tank 611. First slits 619 for metal wires to pass through are provided on both sides of the degreasing sub-tank 612, the first partition 613, and both sides of the electrolytic cell 616. A pump is installed on the degreasing main tank 611.

[0091] When the degreasing tank 61 is in use, the pump first draws the electrolyte from the degreasing mother tank 611 into the electrolytic tank 616. A metal wire is threaded into the first slit 613. At the front of the degreasing sub-tank 612, the raw material filament 17 is wound onto the first winding wheel 614, causing it to wrap several times before being pulled into the electrolytic tank 616. The first winding wheel 614 rotates under the drive of the first rotary motor 615. By controlling and adjusting the speed of the first rotary motor 615, the speed of the incoming wire can be flexibly adjusted. Because the first slit 619 has a certain depth, the raw material filament 17 can be immersed in the electrolyte at the upper end of the electrolytic tank 616. The electrolyte overflows from the upper end of the electrolytic cell 616 to the middle of the degreasing sub-tank 612, and flows along the outlet hole 618 to the degreasing master tank 611. The electrolyte in the degreasing master tank 611 is then pumped back into the electrolytic cell 616, thus realizing a cycle production.

[0092] like Figure 7 As shown, the electroplating production line 7 includes a pre-plating tank 71, multiple electroplating tanks 72, and multiple washing tanks 73. The washing tanks 73 are located at the tail end of the pre-plating tank 71 and each electroplating tank 72. As in Embodiment 1, a first intermediate metal layer is pre-plated, followed by two outer metal layers. Therefore, the electroplating production line 7 is composed of the pre-plating tank 71, washing tank 73, electroplating tank 72, and washing tank 73 connected in series. If the preparation process in Embodiment 2 is used, then... Figure 6 The hot-dip galvanizing production line 18 shown includes a hot-dip galvanizing tank and a washing tank for holding hot-dip galvanizing liquid, so that the raw material coarse wire 17 passes through the hot-dip galvanizing tank and the hot-dip galvanizing liquid covers the raw material coarse wire to form a metal layer.

[0093] Combination Figure 10 , Figure 11 As shown, second winding wheels 74 are provided at both ends of the pre-plating tank 71 and the electroplating tank 72, and the second winding wheels 74 are driven by a second rotary motor. Both the pre-plating tank 71 and the electroplating tank 72 have second slits 75 at their ends for the metal wire 19 to pass through. The second winding wheels 74 are located in the middle of the width of the pre-plating tank 71 or the electroplating tank 72, and the second slits 75 are located at the edge of the width. This arrangement is intended to create a wrap angle when the metal wire 19 enters the second winding wheel 74 along the second slit 75; increasing the wrap angle prevents the metal wire from falling off and slipping.

[0094] Multiple second partitions 76 are installed inside the washing tank 73. Third slits 77 are provided at the ends of the washing tank 73 and above the second partitions 76 for the metal wire to pass through. The third slits 77 are arranged in a staggered pattern, with the second slit 75 at the tail end of the pre-plating tank 71 or electroplating tank 72 corresponding to the third slit 77 at the end of the adjacent washing tank 73; and the third slit 77 at the tail end of the washing tank 73 corresponding to the second slit 75 at the front end of the adjacent electroplating tank 72. This arrangement allows the metal wire to be smoothly drawn.

[0095] like Figure 4 As shown, the raw material wire with a ductile metal layer on the primary take-up device 8 is fed into the high-temperature heating device 10 through the secondary unwinding device 9 for thermal diffusion to form a semi-finished metal wire. The high-temperature heating device 10 can be one of a medium-frequency or high-frequency induction heating furnace, a resistance heating furnace, or a flame heating furnace. A protective gas supply pipe is connected to the heating furnace, which is externally connected to a gas tank. The protective gas can be an inert gas or a reducing protective gas, including hydrogen, ammonia, nitrogen, argon, etc. The thermally diffused semi-finished metal wire is drawn to the secondary surface treatment device 11 for a second surface treatment. The secondary surface treatment device 11 includes a secondary pickling tank, a secondary post-acid washing tank, and a dryer connected in sequence. After the second surface treatment, the semi-finished metal wire is wound onto the secondary take-up device 12.

[0096] like Figure 5 As shown, the semi-finished metal wire on the secondary take-up device 12 is fed into the multi-die cold drawing device 14 via the tertiary feed-out device 13 for multiple cold drawing operations. The cold-drawn metal wire is then transferred to the heat treatment device 15 for heat treatment, and then pulled back to the tertiary feed-out device 13. After multiple cold drawing operations, it is finally wound onto the finished product take-up device 16. The heat treatment device 15 can be an annealing device, which performs annealing after cold drawing to reduce work hardening, eliminate internal stress, and promote grain recrystallization.

[0097] The above description is merely a preferred embodiment of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A manufacturing process for surface-alloyed metal wire, characterized in that: Includes the following steps: S1. Select raw material coarse wire as the inner core matrix of the metal wire; the raw material coarse wire is a chromium group metal or an alloy with chromium group metal as the main component; S2. Perform the first surface treatment on the surface of the raw coarse filaments; S3. A ductile metal layer is coated on the surface of the raw material coarse wire, the ductile metal layer is made of a ductile metal material, the elongation of the ductile metal material is ≥10%; the ductile metal layer includes an intermediate metal layer and one or more outer metal layers, the intermediate metal layer is nickel, cobalt, manganese metal or an alloy thereof; S4. At a temperature of 500℃~1000℃, the ductile metal layer on the surface of the raw material coarse wire is fused into several gradient metal layers to obtain a semi-finished metal wire. S5. Perform a second surface treatment on the surface of the semi-finished metal wire obtained in step S4; S6. Apply lubricant to the surface of the semi-finished metal wire and perform cold drawing at room temperature to deform the semi-finished metal wire into a metal wire of the target diameter.

2. The surface alloying metal wire manufacturing process as described in claim 1, characterized in that: The first surface treatment in step S2 includes: S21. Degreasing: The raw filaments are passed through an alkaline degreasing agent to remove surface oil and oxides; then washed with water to remove any residual alkaline degreasing agent. S22. Pickling: The raw filaments are passed through a pickling solution to neutralize contaminants on the surface of the raw filaments that could not be removed by the alkaline degreasing agent, remove oxides and activate the surface; then washed with water to remove residual pickling solution from the surface. In step S4, an inert gas or a reducing protective gas is used for heating, and the heating method is one of induction heating, resistance heating, flame burning, or high-temperature furnace heating. The second surface treatment in step S5 includes: S51. Secondary pickling: The surface of the semi-finished metal wire is pickled to remove the metal oxides on the surface; water washing: The residual pickling solution on the surface is washed away. S52. Drying, drying the surface water.

3. The surface alloying metal wire manufacturing process as described in claim 1, characterized in that: The raw material filament is tungsten metal or tungsten alloy; the ductile metal material is one or more of the following metal elements: copper, tin, zinc, cobalt, nickel, and manganese.

4. The surface alloying metal wire manufacturing process as described in claim 1, characterized in that: Step S3 involves electroplating a ductile metal layer onto the surface of the raw material coarse wire, specifically including the following steps: S31. Pre-plating: Pre-plating an intermediate metal layer on the surface of the raw material coarse wire, wherein the thickness of the intermediate metal layer H1≤2μm; washing away the residual pre-plating solution on the surface. S32. Electroplating, wherein one or more outer metal layers are electroplated on a pre-plated intermediate metal layer, wherein the thickness of each outer metal layer is less than or equal to 20 μm; Alternatively, in step S3, a ductile metal layer is hot-plated onto the surface of the raw material coarse wire. The ductile metal material is heated and melted at 500℃~1200℃ to form a hot-plating solution. The raw material coarse wire is passed through the hot-plating solution to form a ductile metal layer on the surface of the raw material coarse wire.

5. The surface alloying metal wire manufacturing process as described in claim 4, characterized in that: Two outer metal layers are electroplated on the pre-plated intermediate metal layer. The first outer metal layer is copper or a copper alloy. After electroplating, the residual copper liquid on the surface is washed away. Then, a second outer metal layer is electroplated. The second outer metal layer is zinc, tin or their alloy. After electroplating, the residual liquid on the surface is washed away.

6. The surface alloying metal wire manufacturing process as described in claim 1, characterized in that: In step S6, the wire is cold-drawn multiple times, and the deformation degree of the metal wire is set to 1-10% each time. The lubricant is a water-based lubricant. After each cold drawing, the metal wire is annealed before entering the next drawing.

7. A metal wire, characterized in that: Made using the surface alloying metal wire manufacturing process according to any one of claims 1 to 6, comprising an inner core substrate and a ductile metal layer covering the inner core substrate, wherein the inner core substrate is made of a chromium group metal or an alloy with chromium group metal as the main component.

8. A device for preparing surface alloyed metal wire, characterized in that: The process for manufacturing surface-alloyed metal wire according to any one of claims 1 to 6 comprises, in sequence, a primary wire feeding device, a primary surface treatment device, a metal plating production line, a high-temperature heating device, a secondary surface treatment device, a multi-die cold drawing device, and a finished wire take-up device. The metal plating production line is an electroplating production line or a hot-dip galvanizing production line. The multi-die cold drawing device includes a lubricating fluid tank and multiple drawing dies. The lubricating fluid tank is used to hold lubricating fluid, and the drawing dies are disposed within the lubricating fluid tank. The raw material filament is drawn by the primary wire feeding device to the primary surface treatment device for primary surface treatment, and then drawn to the metal plating production line for electroplating or hot-dip plating at least one layer of ductile metal layer. Raw material coarse wire with a ductile metal layer is thermally diffused in a high-temperature heating device to form a semi-finished metal wire. The high-temperature heating device is connected to a protective gas supply pipe. The thermally diffused semi-finished metal wire is drawn to a second surface treatment device for a second surface treatment, and then fed into a multi-die cold drawing device for multiple cold drawing to form a finished metal wire. Finally, it is wound onto the finished wire take-up device.

9. The surface alloying wire manufacturing apparatus as described in claim 8, characterized in that: It also includes a heat treatment device, wherein the semi-finished metal wire is transferred to the heat treatment device for heat treatment after passing through the multi-die cold drawing device, and then returns to the multi-die cold drawing device for cold drawing. The first surface treatment device includes a degreasing tank, a degreasing water washing tank, an acid pickling tank, and an acid post-acid washing tank connected in sequence; the second surface treatment device includes a secondary acid pickling tank, a secondary acid post-acid washing tank, and a dryer connected in sequence; the electroplating production line includes a pre-plating tank, multiple electroplating tanks, and multiple water washing tanks, with the water washing tanks located at the end of the pre-plating tank and each electroplating tank.

10. The apparatus for preparing surface alloyed metal wire as described in claim 9, characterized in that: The degreasing tank includes a main degreasing tank, a pump, and a sub-degreasing tank located above the main degreasing tank; The degreasing sub-tank has two first partitions in its middle section, dividing it into a front, middle, and rear section. First winding reels are installed in the front and rear sections, driven by a first rotary motor mounted at the bottom of the degreasing sub-tank. Several electrolytic cells for holding electrolyte are installed in the middle of the degreasing sub-tank. Electrode plates are installed in the middle of each electrolytic cell and connected to an external circuit. The number of electrode plates is odd, and their polarity is controlled by an external circuit. A liquid outlet is located at the bottom of the middle section of the degreasing sub-tank, communicating with the main degreasing tank. First slits for metal wires to pass through are provided on both sides of the degreasing sub-tank, the first partitions, and both sides of the electrolytic cells. A pump is installed on the main degreasing tank to transfer electrolyte from the main degreasing tank to the electrolytic cells. The pre-plating tank and the electroplating tank are provided with second winding wheels at both ends. The second winding wheels are driven by a second rotary motor. The ends of the pre-plating tank and the electroplating tank are provided with second slits for metal wires to pass through. The second winding wheels are located in the middle of the width of the pre-plating tank or the electroplating tank, and the second slits are located at the edge of the width of the tank. Multiple second partitions are provided inside the washing tank. Third slits for metal wires to pass through are provided at the end of the washing tank and above the second partitions. The third slits are arranged alternately. The second slit at the tail end of the pre-plating tank or electroplating tank corresponds to the position of the third slit at the front end of the adjacent washing tank. The third slit at the tail end of the washing tank corresponds to the position of the second slit at the front end of the adjacent electroplating tank.

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