Copper rod with zero high-temperature heating defect as well as preparation method and application of copper rod

Abstract

The invention discloses a preparation method of a copper bar with zero high-temperature heating defect, which comprises the following steps of: smelting, up-drawing continuous casting, rolling, coiling, peeling, multi-pass coiling, reserved bottom annealing and drawing, the hydrogen embrittlement grade of the copper rod subjected to upward continuous casting reaches the second grade or below; in the rolling process, the rolling speed is 3-10 m / min, and the machining rate is larger than or equal to 30%. The hydrogen embrittlement grade of the copper rod is reduced, the surface defects of the copper rod are eliminated, and the liquid leakage condition during high-temperature heating is avoided by raising the height of the cooling water tank during upward continuous casting and combining cold machining modes such as rolling and coiling.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of copper alloys, in particular to a copper bar without high-temperature heating defects and a preparation method and application thereof. BACKGROUND

[0002] With the explosive growth of user scale and penetration rate, AI computing power presents exponential growth. According to industry forecasts, the compound growth rate of the AI chip market will exceed 30% from 2024 to 2030. In the high-computing-power scene, heat dissipation becomes a core bottleneck. For example, the power consumption of a single NVIDIA H100 chip is more than 700W, and a large amount of heat dissipation materials are needed. The high-thermal-conductivity performance, excellent electrical conductivity and high-thermal-capacity characteristics of red copper are the first choice for heat dissipation substrates.

[0003] In AI heat dissipation, the requirements for red copper substrates are becoming more and more demanding. In addition to the substrate, a liquid cooling head connected with the substrate is also needed to transfer cooling medium. The liquid cooling head needs to be welded with the substrate, so it needs to be heated to 700-800 DEG C. If air bubble defects occur during heating, leakage will occur during the transfer of the cooling medium. Moreover, the liquid cooling head needs to be bent and machined, so the internal organization of the material needs to be dense.

[0004] The Chinese patent document with the publication number CN116532473A discloses a production system and process for double-zero ultra-fine wire copper wire, which comprises an up-drawing copper rod device, a rod rolling machine and a wire drawing machine. The up-drawing copper rod device comprises a melting furnace, a high-temperature copper liquid purification bin and a heat preservation furnace connected in sequence. The solid electrolytic copper added into the melting furnace is melted into copper liquid, which is covered with charcoal. The copper liquid flowing into the high-temperature copper liquid purification bin is further reduced, which is covered with charcoal and graphite scales in an inlaid manner. The copper liquid is cast into copper wire blanks through a mold in the heat preservation furnace, which is covered with graphite scales. The rod rolling machine rolls the copper wire blanks into rods with a set size, and the wire drawing machine draws the rods into copper monofilaments. By reducing the oxygen content of the up-drawing copper rod, the purpose of ultra-low oxygen content copper wire blanks is achieved, and the internal porosity defects of the ultra-low oxygen content copper wire blanks are prevented, thereby improving the quality of the cast rod.

[0005] The Chinese patent document with the publication number CN116833242A discloses a production process for a high-temperature sintering uniform plate copper plate. By designing the process route and specific process parameters for producing the uniform plate copper strip through the up-drawing continuous extrusion method, a copper strip with low oxygen content and dense and uniform internal organization can be obtained, effectively solving the gas leakage problem caused by the loose and layered defects of the copper strip produced by traditional horizontal continuous casting after high-temperature sintering, and controlling the oxygen content to avoid the problem of uneven bubbling on the surface after sintering.

[0006] But the existing continuous extrusion process, in the continuous extrusion process, the introduction of oxide, can cause the increase of oxygen content in the continuous extrusion product in local position, and the subsequent processing process cannot eliminate the introduced oxygen, resulting in the product prepared reaches five level when hydrogen embrittlement test. If the product prepared by continuous extrusion process is used for preparing liquid cooling head, in the process of high temperature heating, the part with higher hydrogen embrittlement level has very high sensitivity, because of the combined action of high temperature and cooling medium pressure, hydrogen atoms diffuse and enrich to grain boundary quickly, form high pressure water vapor bubble, induce micro crack initiation. At the same time, high temperature reduces the toughness of the material, and the crack propagates along the grain boundary and penetrates the thin wall area of the flow channel, finally leads to the problem of leakage of the transmission cooling liquid medium.

[0007] Therefore, it is urgent to find a preparation method of copper bar which can reduce high temperature heating defects, so that the product prepared is more suitable for preparing AI heat dissipation liquid cooling head. SUMMARY

[0008] In order to solve the above technical problems, the application provides a preparation method of copper bar with zero high temperature heating defects, which raises the height of the cooling water tank during upward continuous casting, combines with rolling, coiling and other cold working forms, reduces the hydrogen embrittlement level of the copper bar, eliminates the surface defects of the copper bar, and avoids the leakage during high temperature heating.

[0009] A preparation method of copper bar with zero high temperature heating defects, comprising the following steps: melting, upward continuous casting → rolling → coiling → skinning → multi-pass coiling → bottom remaining annealing → drawing, In the upward continuous casting process, the cooling water tank is raised to 0.5-2 m above the crystallizer, and the hydrogen embrittlement level of the copper rod after upward continuous casting reaches below level two. In the rolling process, the rolling speed is 3-10 m / min, and the processing rate is greater than or equal to 30%.

[0010] In the traditional crystallizer cooling mode, the cooling water tank is parallel to the crystallizer. In the present application, the cooling water tank is raised, the water tank is raised to prolong the primary cooling zone, the surface layer of the copper rod prepared by upward continuous casting is quickly solidified to form a fine grain layer, the surface crack initiation is inhibited, the cooling intensity of the copper rod is improved, the solidification and shrinkage speed of the copper liquid is improved, the hollow or loose of the copper rod prepared by upward continuous casting is avoided, the rapid cooling also hinders the diffusion of oxygen atoms, reduces the segregation of Cu2O, inhibits the aggregation of oxygen at high temperature, and the hydrogen embrittlement level of the copper rod prepared by upward continuous casting is reduced to below level two. At the same time, in the rolling process, the loose porosity defects in the copper rod are pressed together, otherwise the internal loose porosity cannot be removed in the subsequent pass, which will cause the surface to appear pitting defects during customer machining. In addition, the rolling process can also break the coarse grains of the copper rod prepared by upward continuous casting, and the Cu2O particles of the cast state oxygen segregation are refined to be dispersed, the hydrogen trap effect is enhanced, the hydrogen embrittlement level is reduced to below level two, which is more suitable for high pressure sealing scenes such as liquid cooling head.

[0011] Preferably, in the rolling process, the ellipticity of the rolled copper rod is 0.2-0.5 mm.

[0012] Preferably, in the discing process, the discing processing rate is 6%-12%.

[0013] In the present application, after the copper rod is discing cold processed, the ellipticity can be controlled within 0.05 mm, which ensures that the surface after peeling is uniform in the subsequent peeling process, avoids that the surface pitch marks and other defects cannot be completely removed, and leads to the expansion of surface defects in the subsequent discing pass production, forming cracking defects.

[0014] Preferably, before the peeling process, the hardness of the copper rod is ≥115 HV1.

[0015] Due to the characteristics of high strength and low plasticity of copper alloy, the peeling die is widely used in the production field of copper alloy; however, pure copper is prone to die sticking during peeling, which leads to the inability to remove surface defects, and is less used in the production process of pure copper products. Through the above continuous casting, rolling and discing processes, the hardness of the copper rod is improved to avoid die sticking of the copper rod in the subsequent peeling process, form copper scrap accumulation, and realize stable and uniform peeling of the surface of the copper rod. Surface defects cannot be eliminated in subsequent production, affecting the application of the final product in the preparation of liquid cooling heads.

[0016] Further preferably, in the peeling process, the peeling amount is controlled to be 0.1-0.3 mm. Too small peeling amount leads to the inability to remove surface defects, and too large peeling amount leads to copper rod breakage.

[0017] Preferably, in the multi-pass discing process, the discing speed is controlled to be 15-40 m / min, the single-pass processing rate is controlled to be 10%-20%, and the total processing rate is controlled to be 30%-70%.

[0018] In the present application, by controlling the processing rate of the copper rod, the surface of the copper rod is ensured to be bright and smooth; at the same time, sufficient driving force is provided for bottoming annealing and recrystallization. When the processing rate is lower than this, the grain boundaries of the coarse grain zone generated during the processing process slip, the deformation between the grains is not coordinated, which leads to the unevenness of the surface, and the subsequent processed products cannot completely eliminate the defects.

[0019] Further preferably, in the bottoming annealing process, the annealing temperature is 350-550 ℃, and the annealing time is 1-3 h.

[0020] In the present application, by controlling the annealing temperature and time, the as-cast structure is completely eliminated, the final product realizes complete recrystallization, and the grain size is controlled to be 0.02-0.06 mm.

[0021] Preferably, in the drawing process, the drawing processing rate is 8% to 20%. By controlling the drawing processing rate within the above range, the processing hardness of the product is adjusted so that the Brinell hardness reaches between 80 and 95 HB.

[0022] The present invention also provides a copper rod prepared by the above preparation method, wherein the oxygen content of the copper rod is ≤5 ppm and the hydrogen embrittlement level reaches level one.

[0023] In the present invention, rolling is introduced to press-fit the existing loose defects within the copper rod produced by continuous casting, preventing pitting defects during subsequent surface processing. Subsequent surface peeling can completely remove defects such as pitch lines on the material surface, preventing cracking defects during subsequent cold working. No oxygen is introduced during the entire processing process, ensuring that the finished product reaches a hydrogen embrittlement level of level 1. In contrast, existing continuous extrusion processes introduce oxides during the continuous extrusion process, which can lead to an increase in oxygen content in localized locations within the continuously extruded product. Subsequent processing cannot eliminate the introduced oxygen, resulting in some locations reaching level 5 in the product hydrogen embrittlement test. Therefore, compared to the continuous extrusion process, the product of the present invention completely eliminates the introduction of oxygen, allowing the product to meet the requirements of subsequent high-temperature welding at 700-800°C, while also solving the abnormal problem of loose defects within the structure.

[0024] The present invention also provides the use of the copper rod in preparing an AI heat dissipation liquid cooling head.

[0025] Compared with the prior art, the present invention has the following beneficial effects: In the present invention, by raising the cooling water tank, the water tank is raised to extend the primary cooling zone, so that the surface layer of the copper rod produced by the upward continuous casting is rapidly solidified to form a fine-grained layer, which inhibits the initiation of surface cracks, improves the cooling strength of the copper rod, increases the solidification and shrinkage feeding rate of the copper liquid, and avoids the copper rod produced by the upward continuous casting from becoming hollow or loose. Rapid cooling also hinders the diffusion of oxygen atoms, reduces the segregation of Cu2O, and inhibits the subsequent aggregation of oxygen at high temperatures, so that the hydrogen embrittlement level of the copper rod produced by the upward continuous casting is reduced to below level 2. At the same time, in conjunction with the rolling process, the rolling process can press together the loose air holes defects inside the copper rod. Otherwise, the loose air holes inside cannot be removed in the subsequent passes, which will cause pitting defects on the surface during processing by the client. In addition, the rolling process can also break up the coarse crystals of the copper rod produced by the upward continuous casting, refine the Cu2O particles with cast oxygen segregation into a dispersed distribution, enhance the hydrogen trap effect, and reduce the hydrogen embrittlement level of the copper rod to below level 2, making it more suitable for high-pressure sealing scenarios such as liquid cooling heads. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figures 1-6 The microstructures of the copper rods prepared in Examples 1 to 3 and Comparative Examples 1 to 3 after hydrogen embrittlement level testing are shown. DETAILED DESCRIPTION

[0027] The application will be further described in detail below in connection with examples, but the embodiments of the application are not limited to the following examples.

[0028] The raw materials used in the application are commercially available.

[0029] Example 1: The specification of the copper rod is φ15 mm.

[0030] (1) Melting: Single-layer electrolytic plates with a copper content of 99.99% are selected, and the surface has no obvious copper beans. When adding the electrolytic plates to the melting furnace each time, the electrolytic plates are first placed above the melting furnace, and then they are put into the melting furnace after one minute, so as to ensure that the moisture of the electrolytic plates is fully dried before entering the melting furnace, and to reduce the disadvantages caused by the moisture. The melting furnace and the intermediate bin are covered with carbon particles with a carbon content of more than 98%, and the covering thickness is more than 100 mm. (2) Up-drawing casting: The temperature of the holding furnace is controlled between 1140-1150 ℃, and the holding furnace is covered with graphite scales with a covering thickness of more than 100 mm. The diameter of the copper rod discharged by the up-drawing casting is φ30 mm, the drawing speed of the up-drawing copper rod is controlled at 20 cm / min, the cooling water tank is higher than the crystallizer by 1 m, the material of the up-drawing crystallizer is selected to be copper alloy, and the hydrogen embrittlement test is performed on the up-drawing copper rod. (3) Rolling: After 6 passes of combined hole type rolling, the copper rod is rolled to 22 mm, the rolling speed is 4.5 m / min, the lubricating oil for each pass of rolling is water-based lubricating oil with a concentration of 15%, the total rolling processing rate is controlled at 46.2%, and the ovality of the copper rod after rolling is 0.25 mm. (4) Coiling: The coiling is drawn to 21 mm, the coiling processing rate is 8.9%, the ovality of the outer diameter is 0.02 mm, and the hardness of the copper rod is 119HV1. (5) Skin peeling: The skin peeling is to 20.8 mm, and the skin peeling is without lubrication. (6) Multi-pass coiling: The multi-pass coiling is drawn to 16 mm, the coiling speed is controlled at 20 m / min, and the lubricating oil is pure oil lubrication. (7) Bottom-remaining annealing: The annealing temperature is controlled at 350 ℃, the time is controlled at 1.5 h, the annealing atmosphere is nitrogen, and the surface is bright after annealing. (8) Drawing: The drawing is to 15 mm, the processing rate is 8.8%, the drawing speed is controlled at 20 m / min, the lubricating oil is pure oil lubrication, and the hydrogen embrittlement test at 800 ℃ / 20 minutes is performed on the drawn copper rod product.

[0031] (9) Straightening: The on-line straightening is to a single product straightness of ≤1 mm, and the end has no burr.

[0032] Example 2: The specification of the copper rod is φ14 mm.

[0033] (1) Melting: single-layer electrolytic plate with copper content of 99.99% is selected, and the surface has no obvious copper beans. When adding electrolytic plate into the melting furnace each time, the electrolytic plate is first placed above the melting furnace, and then it is put into the melting furnace after one minute, so as to ensure that the moisture of the electrolytic plate is fully dried before entering the melting furnace, and to reduce the disadvantages caused by the moisture; the melting furnace and the intermediate bin are covered with carbon particles with carbon content of more than 98%, and the covering thickness is more than 100 mm; (2) Up-drawing casting: the temperature of the holding furnace is controlled between 1140-1150 ℃, the holding furnace is covered with graphite scales, and the covering thickness is more than 100 mm; the diameter of the copper rod discharged by the up-drawing casting is φ25 mm, the drawing speed of the up-drawing copper rod is controlled at 25 cm / min, the cooling water tank is higher than the crystallizer by 1 m, the material of the up-drawing crystallizer is selected to be copper alloy, and the hydrogen embrittlement test is performed on the up-drawing copper rod; (3) Rolling: after 4 passes of combined hole type rolling, the copper rod is rolled to 20 mm, the rolling speed is 5 m / min, the water-based lubricating oil with a concentration of 15% is used for lubrication in each pass, the total rolling processing rate is controlled at 36%, and the ovality of the copper rod after rolling is 0.34 mm; (4) Disc round: the disc round is drawn to 19 mm, the disc round processing rate is 9.75%, the outer diameter ovality is 0.03 mm, and the hardness of the copper rod is 123HV1; (5) Skin stripping: the skin is stripped to 18.8 mm, and the skin stripping is without lubrication; (6) Multi-pass disc round: the multi-pass disc round is drawn to 15 mm, the disc round speed is controlled at 25 m / min, and the pure oil lubrication is used; (7) Bottom-remaining annealing: the annealing temperature is controlled at 400 ℃, the time is controlled at 1.5 h, the annealing atmosphere is nitrogen, and the surface is bright after annealing; (8) Drawing: drawing to 14 mm, processing rate is 8.7%, drawing speed is controlled at 25 m / min, lubricating oil is pure oil lubrication; the hydrogen embrittlement test is performed on the drawn copper rod product at 800 ℃ / 20 minutes.

[0034] (9) Straightening: online straightening to single product straightness≤1mm, and end without burr.

[0035] Example 3: the specification of the copper rod is φ13 mm.

[0036] (1) Melting: single-layer electrolytic plate with copper content of 99.99% is selected, and the surface has no obvious copper beans. When adding electrolytic plate into the melting furnace each time, the electrolytic plate is first placed above the melting furnace, and then it is put into the melting furnace after one minute, so as to ensure that the moisture of the electrolytic plate is fully dried before entering the melting furnace, and to reduce the disadvantages caused by the moisture; the melting furnace and the intermediate bin are covered with carbon particles with carbon content of more than 98%, and the covering thickness is more than 100 mm; (2) Up-casting: the temperature of holding furnace is controlled between 1140-1150 ℃, the holding furnace is covered with graphite scales, and the covering thickness is more than 100 mm; the diameter of copper rod discharged by up-casting is φ25 mm, the drawing speed of up-copper rod is controlled at 25 cm / min, the cooling water tank is 1 m higher than the crystallizer, the material of up-casting crystallizer is selected as copper alloy, and the hydrogen embrittlement test is conducted on the up-copper rod; (3) Rolling: after 6 passes of combined hole type rolling, the copper rod is rolled to 18.5 mm, the rolling speed is 6 m / min, the water-based lubricating oil is used for lubrication in each pass, the concentration is 15%, the total rolling processing rate is controlled at 45.2%, and the ovality of the copper rod after rolling is 0.28 mm; (4) Discing: the discing is drawn to 17.5 mm, the discing processing rate is 10.5%, the outer diameter ovality is 0.03 mm, and the hardness of the copper rod is 125 HV1; (5) Skinning: the skinning is to 17.25 mm, and the skinning is without lubrication; (6) Multi-pass discing: the multi-pass discing is drawn to 14 mm, the discing speed is controlled at 25 m / min, and the lubricating oil is pure oil lubrication; (7) Bottom-remaining annealing: the annealing temperature is controlled at 550 ℃, the time is controlled at 2 h, the annealing atmosphere is nitrogen, and the surface is bright after annealing; (8) Drawing: the drawing is to 13 mm, the processing rate is 8.6%, the drawing speed is controlled at 25 m / min, the lubricating oil is pure oil lubrication, and the hydrogen embrittlement test is conducted on the drawn copper rod product at 800 ℃ / 20 min.

[0037] (9) Straightening: the straightening is online, and the straightness of single product is ≤1 mm, and the end is without burr.

[0038] Comparative Example 1: φ15 mm copper rod is prepared by continuous extrusion process (1) Melting: single-layer electrolytic plate with copper content of 99.99% is selected, and there is no obvious copper bean on the surface, when the electrolytic plate is added into the melting furnace each time, the electrolytic plate is first placed above the melting furnace, and then the electrolytic plate is put into the melting furnace after one minute, so that the water in the electrolytic plate is fully dried before entering the melting furnace, and the disadvantages caused by water are reduced; the melting furnace and the intermediate storage bin are covered with carbon particles, the carbon content of the carbon particles is greater than 98%, and the covering thickness is more than 100 mm; (2) Up-casting: the temperature of holding furnace is controlled between 1140-1150 ℃, the holding furnace is covered with graphite scales, and the covering thickness is more than 100 mm; the diameter of copper rod discharged by up-casting is φ20 mm, the drawing speed of up-copper rod is controlled at 45 cm / min, the cooling water tank is 1 m higher than the crystallizer, the material of up-casting crystallizer is selected as copper alloy, and the hydrogen embrittlement test is conducted on the up-copper rod.

[0039] (3) Continuous extrusion: extrusion speed control at 6 rpm / min, overflow control at 5.5%, continuous extrusion blank control at 16 mm; (4) Drawing: drawing cold working to 15 mm, drawing speed control at 20 m / min, pure oil lubrication for lubricating oil; 800℃ / 20min hydrogen embrittlement test for copper bar product drawn to 15 mm; (5) Straightening: online straightening to single product straightness≤1 mm, and end without burr.

[0040] Comparative Example 2: φ14 mm copper bar was prepared by continuous extrusion process (1) Melting: single-layer electrolytic plate with copper content of 99.99% was selected, and there was no obvious copper bean on the surface. When adding electrolytic plate into the melting furnace each time, the electrolytic plate was first placed above the melting furnace, and then it was put into the melting furnace after one minute, so as to ensure that the moisture of the electrolytic plate was fully dried before entering the melting furnace, and to reduce the disadvantages caused by moisture. Carbon particles with carbon content greater than 98% were covered on the melting furnace and the intermediate bin, and the covering thickness was more than 100 mm. (2) Up-drawing casting: the temperature of the holding furnace was controlled between 1140~1150℃, and the holding furnace was covered with graphite scales with a covering thickness of more than 100 mm. The diameter of the copper rod discharged by up-drawing casting was φ20 mm, and the up-drawing casting speed was controlled at 45 cm / min. The cooling water tank was 1 m higher than the crystallizer, the material of the up-drawing crystallizer was selected as copper alloy, and the hydrogen embrittlement test was conducted on the up-drawing copper rod.

[0041] (3) Continuous extrusion: extrusion speed control at 6 rpm / min, overflow control at 5.5%, continuous extrusion blank control at 15 mm; (4) Drawing: drawing cold working to 14 mm, drawing speed control at 25 m / min, pure oil lubrication for lubricating oil; 800℃ / 20min hydrogen embrittlement test for copper bar product drawn to 14 mm; (5) Straightening: online straightening to single product straightness≤1 mm, and end without burr.

[0042] Comparative Example 3: The specification of the copper bar was φ15 mm.

[0043] (1) Melting: single-layer electrolytic plate with copper content of 99.99% was selected, and there was no obvious copper bean on the surface. When adding electrolytic plate into the melting furnace each time, the electrolytic plate was first placed above the melting furnace, and then it was put into the melting furnace after one minute, so as to ensure that the moisture of the electrolytic plate was fully dried before entering the melting furnace, and to reduce the disadvantages caused by moisture. Carbon particles with carbon content greater than 98% were covered on the melting furnace and the intermediate bin, and the covering thickness was more than 100 mm. (2) Up-casting: the temperature of the holding furnace is controlled between 1140-1150 ℃, the holding furnace is covered with graphite scales, the covering thickness is more than 100 mm; the diameter of the up-casting copper rod is φ30 mm, the drawing speed of the up-casting copper rod is controlled at 20 cm / min, the cooling water tank is leveled with the crystallizer, the material of the up-casting crystallizer is selected as copper alloy, and the hydrogen embrittlement test is performed on the up-casting copper rod; (3) Rolling: after 6 passes of combined hole type rolling, the copper rod is rolled to 22 mm, the rolling speed is 4.5 m / min, the water-based lubricating oil is used for lubrication in each pass, the concentration is 15%, the total rolling processing rate is controlled at 46.2%, and the ovality of the copper rod after rolling is 0.28 mm; (4) Discing: the discing is drawn to 21 mm, the discing processing rate is 8.9%, the ovality of the outer diameter is 0.02 mm, and the hardness of the copper rod is 119HV1; (5) Skinning: the skinning is to 20.8 mm, and the skinning is without lubrication; (6) Multi-pass discing: the multi-pass discing is drawn to 16 mm, the discing speed is controlled at 20 m / min, and the pure oil lubrication is used; (7) Bottom-remaining annealing: the annealing temperature is controlled at 350 ℃, the time is controlled at 1.5 h, the annealing atmosphere is nitrogen, and the surface is bright after annealing; (8) Drawing: the drawing is to 15 mm, the processing rate is 8.8%, the drawing speed is controlled at 20 m / min, the pure oil lubrication is used, and the hydrogen embrittlement test at 800 ℃ / 20 min is performed on the drawn copper rod product.

[0044] (9) Straightening: the straightening is in line to make the straightness of the single product ≤1 mm, and the end is without burr.

[0045] Performance test and result analysis (1) Oxygen content detection method: the test is performed according to GB / T 5121.8-2008 Chemical Analysis Methods for Copper and Copper Alloys Part 8: Determination of Oxygen Content.

[0046] (2) Hardness test is performed according to the Brinell method in GB / T 4909.8 Test Methods for Bare Electric Wire Part 8: Hardness Test. The sample length is 10 mm.

[0047] (3) Hydrogen embrittlement grade detection method: the detection is performed on 2 positions of the copper rod every 1.0 mm along the circumference according to YS / T 335-2009 Metallographic Examination Method for Oxygen Content of Oxygen-free Copper.

[0048] Table 1 is the performance test results of Examples 1-3 and Comparative Examples 1 and 2 Figures 1-6The figure of the copper bar prepared by example 1~3 and comparative example 1~3 after hydrogen embrittlement level test, wherein, the surface of the copper bar prepared by example 1~3 has no obvious crack, and the hydrogen embrittlement level reaches the first level, while the surface of the copper bar prepared by comparative example 1 and 2 has obvious continuous crack during the hydrogen embrittlement level test, and the hydrogen embrittlement level is the fourth or fifth level, and the surface of the copper bar prepared by comparative example 3 has discontinuous grain boundary crack during the hydrogen embrittlement level test, and the hydrogen embrittlement level is the third level.

[0049] The preferred embodiments of the present application have been described above with the specific examples, but the present application is not limited to the above examples. Although the present application has been described in detail with the above examples, those skilled in the art can modify the technical solutions described in the above examples, or replace some of the technical features with equivalent ones, without departing from the spirit and principles of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a copper rod with zero high temperature heating defects, characterized in that: The following steps are involved: Melting, continuous casting → rolling → coiling → peeling → multi-pass coiling → bottom annealing → drawing, In the upward continuous casting process, the cooling water tank is raised to 0.5-2 m above the crystallizer, and the hydrogen embrittlement level of the copper rod after the upward continuous casting reaches level 2 or below; In the rolling process, the rolling speed is 3-10 m / min and the processing rate is ≥30%.

2. The method for preparing a copper rod with zero high-temperature heating defects according to claim 1, characterized in that: In the rolling process, the ovality of the copper rod after rolling is 0.2-0.5 mm.

3. The method for preparing a copper rod with zero high-temperature heating defects according to claim 1, characterized in that: In the coiling process, the coiling processing rate is 6% to 12%.

4. The method for preparing a copper rod with zero high-temperature heating defects according to claim 1, characterized in that: Before the peeling process, the hardness of the copper rod is ≥115 HV1.

5. The method for preparing a copper rod with zero high temperature heating defects according to claim 1, characterized in that: In the peeling process, the peeling amount is controlled to be 0.1-0.3 mm.

6. The method for preparing a copper rod with zero high-temperature heating defects according to claim 1, characterized in that: In the multi-pass coiling process, the coiling speed is controlled at 15-40 m / min, the single-pass processing rate is controlled at 10%-20%, and the total processing rate is controlled at 30%-70%.

7. The method for preparing a copper rod with zero high temperature heating defects according to claim 6, characterized in that: In the bottom annealing process, the annealing temperature is 350-550°C and the annealing time is 1-3 hours.

8. The method for preparing a copper rod with zero high-temperature heating defects according to claim 1, characterized in that: In the drawing process, the drawing processing rate is 8% to 20%.

9. A copper rod with zero high-temperature heating defects obtained by the preparation method according to any one of claims 1 to 8, wherein the oxygen content of the copper rod is ≤5 ppm and the hydrogen embrittlement level reaches level 1.

10. Use of the copper rod with zero high-temperature heating defects according to claim 9 in preparing an AI heat dissipation liquid cooling head.

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