阅读说明：本技术 一种铜锌镍合金电极母线及其制备方法 (Copper-zinc-nickel alloy electrode bus and preparation method thereof ) 是由 郑恩奇 叶东皇 于 2020-06-05 设计创作，主要内容包括：本发明涉及一种铜锌镍合金电极母线,其特征在于：该铜锌镍合金电极母线的重量百分比组成为Cu：56.0～62.0wt％、Ni：0.5～3.5wt％、B：0.003～0.01wt％、Sn：0.005～0.02wt％、Pb≤0.007wt％,余量Zn及不可避免的杂质。本发明铜锌镍合金电极母线的强度与塑性高,材料性能均匀,铜锌镍合金电极母线可以实现规格小于φ1.6mm,抗拉强度550MPa以上,延伸率20％以上,满足高速、高精度线切割加工需求。(The invention relates to a copper-zinc-nickel alloy electrode bus, which is characterized in that: the copper-zinc-nickel alloy electrode bus comprises the following components in percentage by weight: 56.0 to 62.0 wt%, Ni: 0.5-3.5 wt%, B: 0.003 to 0.01 wt%, Sn: 0.005-0.02 wt%, Pb less than or equal to 0.007 wt%, and the balance of Zn and inevitable impurities. The copper-zinc-nickel alloy electrode bus has high strength and plasticity and uniform material performance, can realize the specification of less than phi 1.6mm, the tensile strength of more than 550MPa and the elongation of more than 20 percent, and meets the requirements of high-speed and high-precision wire cutting processing.)

1. A copper-zinc-nickel alloy electrode bus is characterized in that: the copper-zinc-nickel alloy electrode bus comprises the following components in percentage by weight: 56.0 to 62.0 wt%, Ni: 0.5-3.5 wt%, B: 0.003 to 0.01 wt%, Sn: 0.005-0.02 wt%, Pb less than or equal to 0.007 wt%, and the balance of Zn and inevitable impurities.

2. The copper-zinc-nickel alloy electrode bus according to claim 1, characterized in that: the copper-zinc-nickel alloy electrode bus also comprises 0.001-0.1 wt% of ER, wherein the ER is selected from at least one of La and Ce.

3. The copper-zinc-nickel alloy electrode bus according to claim 1, characterized in that: the copper-zinc-nickel alloy electrode bus is characterized in that an alpha phase is used as a matrix, a fine beta phase is precipitated on the alpha phase, the area fraction of a columnar alpha phase in the alpha phase is controlled to be below 40%, the beta phase is fine particles, and the longest distance between two points on the particles is 3-5 micrometers.

4. The copper-zinc-nickel alloy electrode bus according to claim 1, characterized in that: the grain size of the copper-zinc-nickel alloy electrode bus is 10-15 microns.

5. The method for preparing the copper-zinc-nickel alloy electrode bus bar according to any one of claims 1 to 4, which is characterized in that: the preparation process of the copper-zinc-nickel alloy electrode bus comprises the following steps: smelting → casting → the first continuous stretching and continuous annealing process → peeling and stretching process → annealing → acid washing → the second continuous stretching and continuous annealing process → inspection; the casting process comprises the following steps: the blank is cast by adopting an upward continuous casting technology, the casting temperature is 1020-1060 ℃, the specification of the blank is phi 8-9 mm, the traction speed is 120-200 cm/min, the traction pitch is 1-8 mm, the back thrust is 1-3 mm, the cooling water inlet temperature is 20-35 ℃, and the cooling water outlet temperature is 30-45 ℃.

6. The method for preparing the copper-zinc-nickel alloy electrode bus according to claim 5, wherein the method comprises the following steps: the elongation of the drawing casting blank is 40-50%, and the elongation deviation of the front end, the middle end and the tail end of the drawing casting blank is controlled to be below 3%.

7. The method for manufacturing a copper-zinc-nickel alloy electrode bus according to claim 5, wherein the first continuous drawing and annealing step comprises: the stretching speed is 240-600 m/min, the annealing temperature is 600-800 ℃, and the total processing rate of continuous stretching is controlled to be 10-90%.

8. The method for preparing the copper-zinc-nickel alloy electrode bus according to claim 5, wherein the method comprises the following steps: the peeling and stretching process adopts the matching of a stretching die and a convex knife edge die; the die core of the drawing die is made of polycrystalline materials; the inclination of the top surface of the convex knife edge die is 24-26 degrees; the scalping amount is controlled to be 0.1-0.6 mm, and the total stretching processing rate is controlled to be 10-60%.

9. The method for manufacturing a copper-zinc-nickel alloy electrode bus according to claim 5, wherein the annealing step comprises: annealing temperature is 300-500 ℃, and heat preservation time is as follows: 2-6 h.

10. The method for manufacturing a copper-zinc-nickel alloy electrode bus according to claim 5, wherein the second continuous drawing and continuous annealing step includes: the stretching speed is 360-660 m/min, the annealing temperature is 500-700 ℃, and the total processing rate of continuous stretching is controlled to be 10-90%.

Technical Field

The invention relates to a copper alloy, in particular to a copper-zinc-nickel alloy electrode bus and a preparation method thereof.

Background

Electric discharge machining, also known as electric discharge machining, is widely used in precision metal machining processes. In the electric discharge machining, a metal to be machined and a tool electrode are immersed in an insulating medium together, and a voltage pulse which changes periodically and rapidly is applied between the metal to be machined and the tool electrode, so that local high temperature is generated between the metal to be machined and the tool electrode due to pulse discharge, and the metal to be machined is melted or gasified through the local high temperature. By controlling the movement between the tool electrode and the metal to be machined and the frequency of the voltage pulses, unnecessary portions are etched away from the metal to be machined, thereby forming a desired specific shape on the metal.

Among various methods of electric discharge machining, electric discharge wire cutting uses a cutting wire (electrode bus) as a tool electrode, and cuts metal by a local high temperature generated by a pulse discharge between a wire rod and a metal to be cut according to the principle of electric discharge machining. In the discharge wire cutting process, the wire rod and the metal to be cut almost have no cutting force, so that compared with the mechanical process, the stress generated by the processing tool on the metal to be cut can be prevented from generating adverse influence on the mechanical property of the metal.

At present, the electrode bus for linear cutting is made of copper-zinc alloy materials generally, zinc has a good gasification chip removal effect when the bus is cut at a high speed, and the linear cutting machining efficiency is improved. However, when the Zn content is higher, the plasticity of the bus material is reduced, the risk of cutting and breaking during wire traveling is increased, and when the specification of the electrode wire is lower than phi 0.3mm, the wire breaking rate reaches 3-5 times per ton or more. In addition, by analyzing the microstructure of the conventional electrode bus, a large amount of columnar alpha phase exists, crystal grains of the microstructure are coarse, the columnar alpha phase causes uneven performance of the copper alloy electrode bus, a part with weak mechanical property is easy to break during wire cutting, and the coarse crystal grains cause strength reduction of the material and easily cause wire breakage.

Therefore, improvement is needed for the existing copper-zinc alloy electrode bus and the preparation method thereof.

Disclosure of Invention

The first technical problem to be solved by the present invention is to provide a cu-zn-ni alloy electrode bus with high strength, good plasticity and uniform performance in view of the above-mentioned current state of the art.

The technical scheme adopted by the invention for solving the first technical problem is as follows: a copper-zinc-nickel alloy electrode bus is characterized in that: the copper-zinc-nickel alloy electrode bus comprises the following components in percentage by weight: 56.0 to 62.0 wt%, Ni: 0.5-3.5 wt%, B: 0.003 to 0.01 wt%, Sn: 0.005-0.02 wt%, Pb less than or equal to 0.007 wt%, and the balance of Zn and inevitable impurities.

In order to improve the plasticity of the existing copper-zinc alloy electrode bus, a certain content of Ni is added into the copper-zinc alloy, the Ni improves the plasticity of the alloy and enables the alloy to have certain high-temperature softening resistance, when the addition amount of the Ni is lower than 0.5 wt%, the plasticity and the high-temperature softening resistance of the electrode bus are not obviously improved, when the addition amount of the Ni is higher than 3.5 wt%, the subsequent processing difficulty is increased, and the raw material cost of the copper-zinc alloy electrode bus is increased. In the application, 0.005-0.02 wt% of Sn is added, so that the shaping is not reduced while the strength of the copper-zinc alloy electrode bus is increased. In the application, 0.003-0.01 wt% of B is added, the B element can be added to refine grains, the grains are fine, high strength can be obtained, the plasticity is not obviously reduced, and the performance of the material is more uniform.

Preferably, the copper-zinc-nickel alloy electrode bus further comprises 0.001-0.1 wt% of ER, wherein the ER is at least one selected from La and Ce. Rare earth elements La and Ce are added to promote elimination of as-cast structure, refine grains, play a role in impurity removal and purification, and reduce the possibility of impurity inclusion and weakening of grain boundaries, thereby reducing the probability of crystal-following cracking during bus wire cutting.

Preferably, the copper-zinc-nickel alloy electrode bus is formed by taking an alpha phase as a matrix, precipitating a fine beta phase on the alpha phase, controlling the area fraction of the columnar alpha phase in the alpha phase to be less than 40%, wherein the beta phase is fine particles, and the longest distance between two points on the particles is 3-5 microns. The copper-zinc-nickel alloy electrode bus takes an alpha phase as a matrix, and a fine beta phase is precipitated on the alpha phase.

The alpha phase is used as a matrix phase, provides strength for the matrix and has excellent shaping, and if casting parameters are improperly controlled during casting, the alpha phase is easy to form coarse columnar crystals which are difficult to eliminate during subsequent processing, so that the performance of the copper-zinc-nickel alloy electrode bus is not uniform, and therefore, in order to improve the uniformity of the performance of the copper-zinc-nickel alloy electrode bus, the area fraction of the columnar alpha phase in the alpha phase is controlled to be below 40%.

The β phase is brittle and hard as compared with the α phase, and mainly provides strength to the alloy, and the larger the β phase is, the more likely the β phase is to be coarse, the more uneven the performance is, and the shape of the material is rapidly reduced, so that the β phase itself is in the form of fine particles, and the longest distance between two points on the particles is controlled to be 3 to 5 μm, in order to obtain uniformity of the performance.

Preferably, the grain size of the copper-zinc-nickel alloy electrode bus is 10-15 microns. The smaller the grain size of the copper-zinc-nickel alloy electrode bus is, the higher the strength is, and the better the uniformity of material performance is, in order to realize the balance of strength and plasticity, the grain size of the copper-zinc-nickel alloy electrode bus is controlled to be 10-15 microns.

The second technical problem to be solved by the present invention is to provide a method for preparing a cu-zn-ni alloy electrode bus in view of the above-mentioned current state of the art.

The technical scheme adopted by the invention for solving the second technical problem is as follows: a preparation method of a copper-zinc-nickel alloy electrode bus is characterized by comprising the following steps: the preparation process of the copper-zinc-nickel alloy electrode bus comprises the following steps: smelting → casting → the first continuous stretching and continuous annealing process → peeling and stretching process → annealing → acid washing → the second continuous stretching and continuous annealing process → inspection; the casting process comprises the following steps: the blank is cast by adopting an upward continuous casting technology, the casting temperature is 1020-1060 ℃, the specification of the blank is phi 8-9 mm, the traction speed is 120-200 cm/min, the traction pitch is 1-8 mm, the back thrust is 1-3 mm, the cooling water inlet temperature is 20-35 ℃, and the cooling water outlet temperature is 30-45 ℃.

The thickness of the solidified shell is continuously thickened by controlling the casting temperature, the traction speed, the traction pitch and the cooling water inlet temperature, and the cooling water outlet temperature has enough strength to be led out from the crystallizer. Set up the backstepping and set up the backstepping volume as 1 ~ 3 mm: firstly, the copper liquid is subjected to the action of mechanical compression during solidification, so that the copper liquid is more fully fed, and the crystalline structure is more compact; secondly, the vibration effect is achieved during crystallization, and crystal grains are refined, so that the strength and the plasticity of the casting blank are improved. The elongation of the finally obtained up-drawing blank can stably reach more than 40 percent, and the up-drawing blank has excellent processing performance.

Preferably, the elongation of the drawing casting blank is 40-50%, and the elongation deviation of the front end, the middle end and the tail end of the drawing casting blank is controlled to be less than 3%. The quality of the blank directly determines the subsequent processing performance and the uniformity of the overall performance of the material, the elongation of the blank is controlled to be 40-50%, the elongation deviation of the front end, the middle end and the tail end of the stretch-cast blank is controlled to be below 3%, the high elongation and the uniformity of the elongation are favorable for continuous subsequent stretching on one hand, and on the other hand, the uniformity of the performance of the electrode bus of the copper-zinc-nickel alloy can be ensured.

Preferably, the first continuous stretch annealing step includes: the stretching speed is 240-600 m/min, the annealing temperature is 600-800 ℃, and the total processing rate of continuous stretching is controlled to be 10-90%.

Preferably, the peeling and stretching process adopts the matching of a stretching die and a convex knife edge die; the die core of the drawing die is made of polycrystalline materials; the inclination of the top surface of the convex knife edge die is 24-26 degrees; the scalping amount is controlled to be 0.1-0.6 mm, and the total stretching processing rate is controlled to be 10-60%. The purpose of the peeling and stretching process is to eliminate burrs on the surface of the blank, and compared with the traditional tungsten steel die, the wire blank after stretching is better in surface quality because the die core of the stretching die is made of polycrystalline materials. The top surface gradient of the convex knife edge die is 24-26 degrees, the resistance in stretching can be effectively reduced, the service life loss of the die is reduced, and the production efficiency and the yield are improved.

Preferably, the annealing step: annealing temperature is 300-500 ℃, and heat preservation time is as follows: 2-6 h. The blank is fully softened in the annealing process, and the internal stress of the material is eliminated. In order to keep higher processing plasticity of the copper-zinc-nickel alloy material under the low-temperature heat treatment processing condition, the annealing temperature is set to be 300-500 ℃, so that the energy consumption is reduced, the production cost is saved, and the risk of greatly reducing the strength of a final finished product material due to the growth of a grain structure caused by overhigh temperature is avoided.

Preferably, the second continuous stretch continuous annealing step: the stretching speed is 360-660 m/min, the annealing temperature is 500-700 ℃, and the total processing rate of continuous stretching is controlled to be 10-90%. The continuous stretching and continuous annealing process can realize continuous and synchronous production operation, greatly improves the production efficiency, controls the material performance by matching the stretching speed and the annealing temperature, and can obtain a single finished product with the quality of more than 800 kg/coil.

Compared with the prior art, the invention has the advantages that: in order to improve the strength and plasticity of the copper-zinc alloy electrode bus, a proper amount of Ni is added into the copper-zinc alloy, the plasticity and the high-temperature softening resistance of the material are improved by the Ni element, the B element is added to play a role in refining grains, the formation of a thick columnar alpha phase is avoided, and the uniformity of the material performance is improved; adding trace Sn element to properly improve the strength of the material; the copper-zinc-nickel alloy electrode bus can realize the specification of being smaller than phi 1.6mm, the tensile strength of more than 550MPa, the elongation of more than 20 percent, uniform performance and excellent high-temperature processing performance, and meets the requirements of high-speed and high-precision wire cutting processing.

Drawings

FIG. 1 is a metallographic photograph (magnified 200 times) of a Cu-Zn-Ni alloy electrode bus bar according to example 1 of the present invention.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.