CN114438358B - Layered gradient copper-chromium alloy and preparation method thereof - Google Patents
Layered gradient copper-chromium alloy and preparation method thereof Download PDFInfo
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- CN114438358B CN114438358B CN202210130815.6A CN202210130815A CN114438358B CN 114438358 B CN114438358 B CN 114438358B CN 202210130815 A CN202210130815 A CN 202210130815A CN 114438358 B CN114438358 B CN 114438358B
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
- C22C1/03—Making non-ferrous alloys by melting using master alloys
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
- B21C37/04—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of bars or wire
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/525—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length for wire, for rods
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C9/00—Alloys based on copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C9/00—Alloys based on copper
- C22C9/02—Alloys based on copper with tin as the next major constituent
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C9/00—Alloys based on copper
- C22C9/06—Alloys based on copper with nickel or cobalt as the next major constituent
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/08—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of copper or alloys based thereon
Abstract
The invention discloses a layered gradient copper-chromium alloy and a preparation method thereof, the method comprises alloy smelting, surface milling, extrusion or rolling, internal oxidation, aging, cold rolling or cold drawing to obtain a finished product, the chromium content in the alloy is controlled to be 0.1-0.6% in weight percentage, and the material contains 0.01-0.3% of one or more alloy elements of Co, zr, ti, mg, sn, fe and the like. According to the invention, through matching control of alloy components, an internal oxidation process, an aging process and deformation, the prepared gradient composite material has high surface conductivity and high core strength, so that the high strength and high conductivity of the alloy material are ensured. The process is easy to control and implement, high in production efficiency, short in period and convenient for large-scale production.
Description
Technical Field
The invention relates to the technical field of copper alloy materials and preparation thereof, in particular to a layered gradient copper-chromium alloy and a preparation method thereof.
Background
The contact wire is a cable for transmitting power, is widely applied to industries such as railways, subways and the like which are related to national civilian life, and not only is high conductivity required, but also high strength is required. The contact wire is distributed as an important component of an electrified railway contact network, electric energy is transmitted to a locomotive from a traction substation through direct contact with a pantograph slide plate of an electric locomotive, the running safety and the speed of the railway locomotive are directly influenced, and the contact wire is a key component for ensuring the normal operation of the electrified railway. With the rapid development of high-speed railways in China, the operation speed is higher and higher, and the requirement on contact lines is higher and higher, on one hand, the material is required to have higher strength to meet the requirement on tension of the erection lines, for example, the tension of the contact network lines in the safe operation of the high-speed railways of more than 350km/h is more than or equal to 30kN, and the tensile strength and the conductivity performance indexes of the contact line material are respectively required to reach 530MPa and 72 percent IACS. It is reported that the electricity consumption of 350km/h of the high-speed railway running for 1h is about 10000 kilowatt hours, and if the conductivity of the contact line is improved by 1% IACS, the energy consumption can be reduced by more than 20 billion yuan per year by only running the high-speed railway.
At present, the mainstream material of the domestic high-speed railway contact line is Cu-Mg alloy, the strength of the Cu-Mg alloy can reach about 550MPa, but the highest conductivity is about 73% IACS. At present, the Cu-Cr-Zr alloy with higher performance has better performance, the strength can reach 600MPa, the conductivity can also reach 78% IACS, but the preparation difficulty is very high, the performance of the current batch is very unstable, and the large-scale application in a short time can not be realized. The layered gradient Cu-Cr composite material disclosed by the invention is simple in preparation process and stable in performance, and on the basis that the strength meets the requirement, the conductivity is obviously improved, so that the running cost of a high-speed railway is reduced.
Disclosure of Invention
The invention aims to solve the technical problem of providing a layered gradient copper-chromium alloy material and a preparation method thereof aiming at the current situation of the prior art of a contact wire. The high-strength and high-conductivity copper alloy contact line prepared by the process has the advantages of simple preparation process, easy control and convenience for production and large-scale production.
The technical scheme adopted by the invention for solving the problems is as follows:
a preparation method of a layered gradient copper-chromium alloy comprises the following steps:
step 1: smelting a Cu-Cr-X alloy ingot in a vacuum induction smelting furnace by taking 0.1-0.6% of Cr,0.01-0.3% of a third alloy element X and the balance of Cu according to the weight percentage of the copper, the copper-chromium intermediate alloy and the third alloy element intermediate alloy, and milling the surface to remove surface defects and oil stains;
step 2: extruding and drawing the cast ingot with the surface treated into a bar at a certain extrusion temperature and a certain extrusion ratio;
and step 3: carrying out an internal oxidation treatment process on the material obtained in the step 2, wherein the internal oxidation temperature is 920-1000 ℃, and the heat preservation is carried out for 2.2-13h;
and 4, step 4: carrying out cold drawing treatment on the internal oxidized layered gradient Cu-Cr-X composite material, wherein the deformation is controlled to be 30-50%;
and 5: carrying out aging treatment on the material obtained in the step 4 at certain annealing temperature and time;
step 6: and (3) carrying out cold rolling treatment on the aged Cu-Cr-X composite material, wherein the deformation amount is 30-70%.
Preferably, the third alloy element X in step 1 is one or more of Co, zr, ti, mg, sn and Fe.
Preferably, the extrusion temperature in step 2 is 780 ℃ to 850 ℃ and the drawing is performed to form a rod (wire) with the diameter of 20 mm to 40 mm.
Preferably, the internal oxidation treatment process in step 3 is internal oxidation sequentially under different oxygen contents: firstly, placing a sample in an internal oxidation furnace, heating the sample to the internal oxidation temperature of 920-1000 ℃ along with the furnace, then introducing mixed gas with low oxygen content, then preserving the heat for 2-12h, then introducing mixed gas with high oxygen content, and preserving the heat for 0.2-1h; the low-oxygen content mixed gas refers to the volume ratio N of normal pressure introduced at the internal oxidation temperature 2 :Ar:O 2 1 volume ratio of =90The mixed gas of (1), wherein Ar is used for adjusting the oxygen content ratio; the mixed gas with high oxygen content refers to N introduced into the normal pressure at the internal oxidation temperature 2 ：O 2 =1:1 volume ratio of mixed gas.
Preferably, the aging treatment temperature in the step 5 is 400-600 ℃, and the aging time is 0.5-2h. More preferably, the aging treatment temperature is 450-550 ℃, and the aging time is 0.5-1.5h.
The invention also aims to provide a layered gradient Cu-Cr-X alloy contact wire which is prepared by the preparation method and is divided into a surface layer and a core part, wherein the surface layer is pure copper and a small amount of impurity oxides, and the core part is a Cu-Cr-X alloy matrix. The thickness of the surface layer ranges from 110 mu m to 1160 mu m.
The metal wire has a skin effect due to the conduction, namely when the metal wire conducts electricity, the current mainly passes through the surface layer of the wire, and the proportion of the core part participating in the conduction is low. Based on the principle of skin effect, the invention designs the layered gradient material with high surface conductivity and high core strength. The conventional mechanically-combined layered material has the defects of non-compact combination between layers and reduction of the comprehensive performance of the material, so the invention designs a layered gradient composite material preparation technology with good combination between layers. It is characterized in that:
the preferable Cu-Cr-X alloy material is added with a small amount of second and third components such as Cr, co, zr, ti, mg, sn, fe and the like, and has high solid solubility in copper at high temperature and extremely low solid solubility at room temperature, or compounds can be formed among the second component, the third component and copper. The alloy elements can form a second phase dispersed and precipitated during subsequent heat treatment, so that the effect of dispersion strengthening is achieved, and the strength of the alloy is improved.
The internal oxidation technology is to react oxygen with alloy elements or impurity elements in the Cu-Cr-X alloy to form oxides, so that the surface layer of the Cu-Cr-X alloy material is purified, the alloy surface layer achieves the performance of pure copper, the conductivity is greatly improved to more than 95% IACS, and the high-temperature performance and the wear resistance of the surface layer can be improved on the premise of not reducing the conductivity due to the existence of the oxides. The control of the internal oxidation oxygen content aims at selective oxidation, alloy elements and impurities are oxidized into oxides while the matrix copper is not oxidized, the oxidation of alloy components and the depth of an oxide layer are ensured at a low oxygen content stage, and the impurities in the matrix are oxidized at a high oxygen content stage, so that the conductivity of a surface layer is further improved. The phase change of the Cu-Cr-X alloy material after internal oxidation is as follows: the surface layer is pure copper, trace alloy elements and impurity element oxides, and the core part is a Cu-Cr-X alloy matrix. The effective internal oxide layer thickness is in the range of 110 μm-1160 μm.
The first cold deformation aims at forming a deformed structure in the alloy material, increasing the distortion degree of the material and increasing the driving force for the precipitation of a second phase during aging; the aging treatment aims at separating out the alloy elements in a supersaturated solid solution formed by the Cu-Cr-X alloy material core during internal oxidation to form a second phase which is dispersed and distributed, so that the effect of hindering dislocation movement is achieved when the material is deformed, and the strength of the material is improved; the purpose of the secondary cold deformation is to adjust the work hardening degree and the strengthening proportion of the work strengthening, so that the final performance of the Cu-Cr-X layered gradient composite material is adjusted according to the requirement.
The layered gradient composite material prepared by the technology has high conductivity on the surface layer, high strength and good conductivity on the inner layer, and high strength and high conductivity of the whole material. The interface between layers of the layered gradient material is well combined, no layering phenomenon exists, the grain boundary of the material can cross the surface layer and the inner layer, the conductivity of the surface layer is more than 90% IACS, the strength of the inner layer is more than 500MPa, after the material is processed and deformed, the integral strength of the material is more than 540MPa, and the conductivity is more than 75% IACS.
Compared with the prior art, the invention also has the following advantages:
1. the base material of the material has the advantages of simple preparation, mature process, low production cost, simple and stable preparation process and stable and reliable product quality.
2. The technology for preparing the layered gradient composite material is convenient to control, easy to realize, environment-friendly in production process and free of pollution. The interface between layers of the prepared layered gradient composite material is well combined, the phenomenon of cracking or falling off can not occur, and the processing performance is excellent.
3. The layered gradient composite material prepared by the invention can simultaneously meet the requirements of the contact line on the strength and the conductivity of the material, and obtains high conductivity while ensuring high strength. The difficult problem of high difficulty in preparing the Cu-Cr-Zr alloy is avoided, the performance of the Cu-Cr-Zr alloy is basically achieved, and the optimized combination of material strength and high conductivity is realized.
Drawings
FIG. 1 is a metallographic photograph of a gradient copper chromium alloy prepared according to specific example 1 of the present invention.
FIG. 2 is a metallographic photograph of a gradient Cu-Cr alloy prepared according to example 2 of the present invention.
FIG. 3 shows the morphology and calibration of a precipitated phase of a gradient copper-chromium alloy core prepared according to embodiment 2 of the present invention.
FIG. 4 shows the morphology and calibration of the surface oxide of the gradient Cu-Cr alloy prepared in example 2 of the present invention.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Example 1:
the embodiment provides a preparation method of a layered gradient copper-chromium alloy, which is specifically carried out according to the following steps:
step 1: taking 0.5 percent of Cr,0.1 percent of Ti and the balance of Cu by weight percent of copper, copper-chromium intermediate alloy and copper-titanium intermediate alloy, smelting a Cu-Cr-Ti alloy ingot in a vacuum induction smelting furnace, and milling the surface to remove surface defects, oil stains and the like;
and 2, step: extruding the cast ingot with the surface treated at 820 ℃ to form a wire rod with the diameter of 30 mm;
and 3, step 3: subjecting the material obtained in step 2 to a treatment under low oxygen content (N) 2 :Ar:O 2 ＝909: 1), carrying out internal oxidation at the temperature of 960 ℃, keeping the temperature for 3h, and then carrying out internal oxidation under the condition of high oxygen content (N) 2 :O 2 1) internal oxidation for 30min, wherein the internal oxidation temperature is 960 ℃;
and 4, step 4: carrying out cold drawing treatment on the internal oxidized layered gradient Cu-Cr-Ti composite material, wherein the deformation amount is 40% (first deformation);
and 5: annealing the material obtained in the step 4 at 500 ℃ for 1h to obtain an aging state Cu-Cr-Ti composite material;
and 6: and (4) carrying out 70% cold drawing treatment (secondary deformation) on the aged Cu-Cr-Ti composite material.
In this example, referring to fig. 1, it can be seen from the microstructure that the surface layer and the inner layer of the composite material have a distinct boundary, but it can be seen that the grain boundary penetrates through the inner layer and the surface layer, which indicates that the internal oxidation does not change the grain distribution of the material, the interface bonding is very good, and no cracking or falling-off phenomenon occurs. The surface layer conductivity of the composite material reached 96.7% iacs, and the properties of the finished product after deformation were: the electrical conductivity of the finished composite material is 75.8 percent IACS, and the strength reaches 559MPa.
The preparation steps of examples 2-10 are essentially the same as in example 1, with slight differences in alloy composition and processing.
The specific example process parameters and performance are tabulated as follows:
finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equally replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (4)
1. A laminar gradient Cu-Cr-X alloy is characterized by comprising a surface layer and a core part, wherein the surface layer is made of pure copper and a small amount of impurity oxides, and the core part is a Cu-Cr-X alloy matrix; the preparation method of the laminar gradient Cu-Cr-X alloy comprises the following steps:
step 1: smelting a Cu-Cr-X alloy ingot in a vacuum induction smelting furnace by taking 0.1-0.6% of Cr,0.01-0.3% of a third alloy element X and the balance of Cu according to the weight percentage of the copper, the copper-chromium intermediate alloy and the third alloy element intermediate alloy, and milling the surface to remove surface defects and oil stains;
and 2, step: extruding and drawing the cast ingot with the surface treated into a bar at a certain extrusion temperature and a certain extrusion ratio;
and step 3: and (3) carrying out an internal oxidation treatment process on the material obtained in the step (2), wherein the internal oxidation treatment process comprises the following steps of sequentially carrying out internal oxidation under different oxygen contents: firstly, placing a sample in an internal oxidation furnace, heating the sample to the internal oxidation temperature of 920-1000 ℃ along with the furnace, introducing mixed gas with low oxygen content, preserving the heat for 2-12h, introducing mixed gas with high oxygen content, and preserving the heat for 0.2-1h; the low-oxygen content mixed gas refers to N introduced into the reactor at normal pressure at the internal oxidation temperature 2 :Ar:O 2 A mixed gas of = 90; the mixed gas with high oxygen content is N introduced into the reactor at normal pressure at the internal oxidation temperature 2 ：O 2 =1:1 volume ratio of mixed gas;
and 4, step 4: carrying out cold drawing treatment on the internal oxidized layered gradient Cu-Cr-X composite material, wherein the deformation is controlled to be 30-50%;
and 5: carrying out aging treatment on the material obtained in the step 4 at certain annealing temperature and time;
step 6: and (3) carrying out cold rolling treatment on the aged Cu-Cr-X composite material, wherein the deformation amount is 30-70%.
2. The layered gradient Cu-Cr-X alloy of claim 1, wherein the third alloying element X in step 1 is one or more of Co, zr, ti, mg, sn, fe elements.
3. The layered gradient Cu-Cr-X alloy of claim 1, wherein the aging temperature in step 5 is 400-600 ℃ and the aging time is 0.5-2h.
4. The layered gradient Cu-Cr-X alloy of claim 1, having a skin thickness in a range of 110 μ ι η to 1160 μ ι η.
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| JP4563480B2 (en) * | 2008-11-28 | 2010-10-13 | Ｄｏｗａメタルテック株式会社 | Copper alloy sheet and manufacturing method thereof |
| CN102108451A (en) * | 2011-02-15 | 2011-06-29 | 常州大学 | Preparation method of copper alloys with high strength and high electric conductivity |
| CN102154572B (en) * | 2011-05-25 | 2012-12-19 | 宁波汉博贵金属合金有限公司 | Method for preparing sliver-tin oxide and indium oxide electrical contact material by gradient internal oxidation method |
| CN103695825B (en) * | 2013-12-31 | 2016-05-04 | 上海电缆研究所 | A kind of preparation method of high-strength copper Cr-Zr alloy fine rule conductor of high conductivity |
| CN103966475B (en) * | 2014-05-15 | 2015-12-02 | 江西理工大学 | A kind of copper chromium titanium alloy osculatory and preparation method thereof |
| CN106086504B (en) * | 2016-05-16 | 2018-03-09 | 浙江大学 | Superpower high-conductivity copper alloy as more than 400 kilometers high-speed railway contact line materials applications of speed per hour |
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