阅读说明：本技术 一种耐高温稀土热管坯及其制备方法 (High-temperature-resistant rare earth heat pipe blank and preparation method thereof ) 是由 陈岩 李坤 肖桥平 游婧 于 2021-07-21 设计创作，主要内容包括：本发明公开了一种耐高温稀土热管坯及其制备方法。具体步骤如下：熔炼保护,将电解铜板加热熔化,控制熔体温度,并加大熔化炉木炭覆盖厚度；洗炉,主要是降低P含量,在熔化炉里先采用氧化捞渣的办法降低P含量,然后,再通过加入纯铜不断稀释的方法,进一步降低熔化炉、铸造炉里面的P含量；在线监控O、P含量,当其小于10ppm以下时,开始投加稀土中间合金,降低铜管牵引速度,提高铸造炉熔体温度,连续铸造铜管铸坯；通过ICP在线监测铸坯稀土含量；采用三辊行星轧制、联合拉拔、盘拉等工序获得耐高温稀土热管坯。本发明制备的稀土热管管坯,经烧结弯曲和压扁加工后,表面质量良好,满足高精密热管材料加工要求。(The invention discloses a high-temperature-resistant rare earth heat pipe blank and a preparation method thereof. The method comprises the following specific steps: smelting protection, namely heating and melting the electrolytic copper plate, controlling the temperature of a melt, and increasing the charcoal coverage thickness of a melting furnace; washing the furnace, mainly reducing the P content, firstly reducing the P content in the melting furnace by adopting an oxidation slag-off method, and then further reducing the P content in the melting furnace and the casting furnace by adding pure copper for continuous dilution; the content of O, P is monitored on line, when the content is less than 10ppm, rare earth intermediate alloy is added, the traction speed of the copper pipe is reduced, the melt temperature of the casting furnace is increased, and the copper pipe casting blank is continuously cast; monitoring the rare earth content of the casting blank on line through ICP; the high-temperature resistant rare earth hot tube blank is obtained by adopting the procedures of three-roller planetary rolling, combined drawing, disc drawing and the like. The rare earth heat pipe blank prepared by the invention has good surface quality after sintering, bending and flattening processing, and meets the processing requirements of high-precision heat pipe materials.)

1. The preparation method of the high-temperature-resistant rare earth hot tube blank is characterized by comprising the following steps of:

s1) smelting protection: heating and melting an electrolytic copper plate, controlling the temperature of a melt, and increasing the covering thickness of charcoal of a melting furnace and the covering thickness of graphite flakes of a casting furnace;

s2), washing the furnace, namely reducing the content of P in the melting furnace by adopting an oxidation slag-removing method, and then further reducing the content of P in the melting furnace and the casting furnace by adding pure copper;

s3), monitoring the O, P content on line, and when the content is less than 10ppm, starting to add rare earth intermediate alloy, reducing the traction speed of the copper pipe, increasing the melt temperature of a casting furnace, and continuously casting a copper pipe casting blank;

s4) monitoring the rare earth content of the casting blank on line through ICP;

s5) adopting three-roller planetary rolling, combined drawing and coiling to obtain the high-temperature resistant rare earth hot tube blank.

2. The preparation method according to claim 1, wherein the thickness of the charcoal and the graphite flakes in S1) is 50cm to 80cm, and the mass ratio of the charcoal to the graphite flakes is 1: 1, wherein the graphite flakes are placed on the charcoal at the lower part, and the charcoal is replaced every 1.5 to 2 hours.

3. The method according to claim 1, wherein the oxidation dragout reduction P in S2) is less than 20 ppm;

the said method of diluting with purified copper further reduces the P content to less than 10 ppm.

4. The preparation method according to claim 1, wherein the master alloy in S3) is a rare earth master alloy, the drawing speed of the copper pipe is 200-400 mm/min, the melt temperature of the casting furnace is 1160-1180 ℃, the diameter of the cast pipe blank is phi 92-25 mm, and the wall thickness is 24-25 mm.

5. The preparation method according to claim 4, wherein the rare earth lanthanum content in the rare earth master alloy is 10-20%, the weight of the added master alloy single block is 1-1.5 kg, and the rare earth master alloy is subjected to preheating treatment before adding.

6. The preparation method according to claim 5, wherein the preheating treatment process is: the baking treatment is carried out for 30-40 minutes at the baking temperature of 400-500 ℃.

7. The method as claimed in claim 1, wherein the content of lanthanum in S4) is 30-70 ppm.

8. The preparation method according to claim 1, wherein the diameter of the high-temperature-resistant rare earth hot tube blank obtained in S5) is 5-8 mm, and the wall thickness is 0.1-0.4 mm.

9. The preparation method according to claim 1, wherein the grain size of the prepared high temperature resistant rare earth heat pipe blank is 50-100 μm after high temperature sintering at 880-; and after sintering, bending and flattening tests show that the surface roughness of the sintered ceramic is 2000-3000 nm.

10. A high temperature resistant rare earth heat pipe blank, characterized in that the high temperature resistant rare earth heat pipe blank is prepared by the method of any one of claims 1-8.

Technical Field

The invention belongs to a copper alloy material processing technology, and relates to a high-temperature-resistant rare earth heat pipe blank mainly applied to a heat dissipation material of 5G communication electronic equipment and a preparation method thereof.

Background

At present, electronic equipment in the 5G era faces important heat conduction and dissipation problems, which also becomes one of the "neck of card" problems in the field of consumer electronics. In recent years, heat pipe technology has begun to be applied to the field of heat dissipation of electronic devices. The pure copper pipe blank is a key material of the electronic heat pipe, the capillary structure in the heat pipe is usually a braided mesh wire or copper powder particles, and the capillary structure is attached to the inner wall of the copper pipe by adopting a high-temperature sintering process (not less than 920 ℃) in production. And the pure copper tube in a drawing state also has serious grain growth after sintering. And the heat pipe structure which is coarsened seriously weakens the deformation capability of the heat pipe, particularly the surface quality after forming. At present, in the application of high-end electronic equipment, the surface of a bent part of a heat pipe has a remarkable orange peel-shaped roughening phenomenon. The undulation of the surface of the heat pipe affects the fit tightness, gaps are formed to reduce heat transfer, and micro cracks formed on the surface are easy to oxidize and corrode. Therefore, the tube wall structure of the sintered heat pipe and the surface quality after bending become a pair of restriction factors, and the application of the domestic heat pipe in high-end electronic equipment is also limited. How to break through the constraint relation and prepare the heat pipe material with good surface quality and the process method are extremely important scientific problems and urgent industrial problems to be solved.

The essence of the surface roughening defect is a residual uneven displacement field on the surface of a polycrystalline metal material in the plastic deformation process, and the surface roughening phenomenon to a certain extent can be formed when the displacement of individual crystal grains on the original surface exceeds the original plane after the plastic deformation, and macroscopically visible orange peel-shaped defects can be formed when the displacement is serious. The factors causing surface roughening can be divided into internal and external factors, the internal factors being mainly related to the texture of the material; external factors are mainly related to deformation modes, process parameters, friction conditions and the like. For the heat pipe, the current sintering process is difficult to avoid, and the heat pipe can be heated in the bending process or the surface roughening degree can be reduced by adopting a multi-pass bending mode and the like, so that the production efficiency can be reduced, and the cost can be increased. Therefore, the patent proposes a new idea of regulating and controlling the wall structure of the heat pipe by adding rare earth elements to solve the problem.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a high-temperature-resistant rare earth heat pipe blank and a preparation method thereof, which solve the problem of surface roughening of bending and flattening processing of a heat pipe, are used for large-scale mass production of high-surface-quality heat pipe materials and are applied to preparation of heat dissipation materials of high-end electronic equipment in the field of 5G communication.

In order to achieve the purpose, the technical scheme of the invention is as follows: a preparation method of a high-temperature-resistant rare earth hot tube blank comprises the following steps:

s1) smelting protection: heating and melting an electrolytic copper plate, controlling the temperature of a melt, and increasing the covering thickness of charcoal of a melting furnace and the covering thickness of graphite flakes of a casting furnace;

s2), washing the furnace, namely reducing the content of P in the melting furnace by adopting an oxidation slag-removing method, and then further reducing the content of P in the melting furnace and the casting furnace by adding pure copper;

s3), monitoring the O, P content on line, and when the content is less than 10ppm, starting to add rare earth intermediate alloy, reducing the traction speed of the copper pipe, increasing the melt temperature of a casting furnace, and continuously casting a copper pipe casting blank;

s4) monitoring the rare earth content of the casting blank on line through ICP;

s5) adopting three-roller planetary rolling, combined drawing and coiling to obtain the high-temperature resistant rare earth hot tube blank.

Further, the thickness of the charcoal and the graphite flakes in the S1) is 50 cm-80 cm, and the mass ratio of the charcoal to the graphite flakes is 1: 1, graphite flakes are placed on the upper part of charcoal, and the charcoal is replaced every 1.5 to 2 hours.

Further, the content of P in the oxidation slag removal in the S2) is reduced to be less than 20 ppm.

The said method of diluting with purified copper further reduces the P content to less than 10 ppm.

Further, the intermediate alloy in the step S3) is a rare earth intermediate alloy, the traction speed of the copper pipe is 200-400 mm/min, the melt temperature of the casting furnace is 1160-1180 ℃, the diameter of the cast pipe blank is phi 92-25 mm, and the wall thickness is 24-25 mm.

Furthermore, the content of rare earth lanthanum in the rare earth intermediate alloy is 10-20%, and the weight of the added intermediate alloy single block is 1-1.5 kg.

Further, the content of the rare earth lanthanum tested in the S4) is 30-70 ppm.

Further, after the high-temperature resistant rare earth heat pipe blank prepared in the step S5) is subjected to high-temperature sintering at 880-; and after sintering, bending and flattening tests show that the surface roughness of the sintered ceramic is 2000-3000 nm.

The high-temperature-resistant rare earth heat pipe blank is prepared by the method.

The invention has the following advantages and beneficial effects:

1. the invention has short processing and preparation process flow, easy operation and simple process, and is convenient for forming large-scale batch production.

2. The rare earth heat pipe blank prepared by the invention has good surface quality after sintering, bending and flattening processing, and meets the processing requirements of high-precision heat pipe materials.

Drawings

FIG. 1 is a schematic view of a microstructure of a sintered heat pipe without rare earth added in example 1 of the present invention.

FIG. 2 is a schematic view of a microstructure of a sintered heat pipe with rare earth added in example 1 of the present invention.

FIG. 3 is a schematic view of a microstructure of a sintered heat pipe without rare earth added in example 2 of the present invention.

FIG. 4 is a schematic view of a microstructure of a sintered heat pipe with rare earth added in example 2 of the present invention.

FIG. 5 is a schematic diagram of the distribution morphology of the Cu-La second phase at the twin boundary observed by a transmission electron microscope in example 1 of the present invention.

FIG. 6 is a schematic diagram of the EBSD microstructure after sintering without adding a rare earth heat pipe in embodiment 2 of the present invention.

FIG. 7 is a schematic diagram of the EBSD microstructure after sintering by adding a rare earth heat pipe in embodiment 2 of the present invention.

Detailed Description

The technical solution of the present invention is further described with reference to the following specific embodiments.

In a specific embodiment, the invention provides a preparation method of a high-temperature-resistant rare earth hot tube blank, which comprises the following specific steps:

1) heating and melting the electrolytic copper plate, and controlling the temperature of the melt to be in the range of 1150-1170 ℃.

2) Smelting protection, namely increasing the covering thickness of charcoal in a melting furnace and the covering thickness of graphite scales in a casting furnace, isolating air and preventing oxygen in the air from entering a copper melt. The thickness is 50 cm-80 cm, and the charcoal is replaced every two 1.5-2 hours.

3) The furnace washing mainly reduces the phosphorus content, firstly reduces the phosphorus content to about 20ppm by adopting an oxidation slag-off method in a melting furnace, and then controls the phosphorus content in the melting furnace and a casting furnace to be below 10ppm by a continuous dilution method.

4) The content of O, P is monitored on line, and when the content is less than 10ppm, the rare earth master alloy is started to be added. The rare earth master alloy is added in the following way: the content of rare earth lanthanum in the rare earth intermediate alloy is 10-20%, the weight of a single piece of the added intermediate alloy is 1-2 kg, the intermediate alloy is added before 10 minutes of liquid rotation in each furnace of a melting furnace, the intermediate alloy is baked for 30-40 minutes before the addition, and the baking temperature is 400-500 ℃.

5) And horizontally and continuously casting a copper pipe casting blank with the diameter phi of 92-94 mm and the wall thickness of 24-25 mm, wherein the copper pipe traction speed is within the range of 200-400 mm/min, the melt temperature of the casting furnace is increased to be within the range of 1160-1180 ℃.

6) And the content of rare earth in the casting blank is monitored on line through ICP (inductively coupled plasma), so that the content of rare earth lanthanum in the casting blank is 30-100 ppm.

7) And the finished product of the electronic rare earth heat pipe blank with the diameter of 5-8 mm and the wall thickness of 0.1-0.4 mm is obtained by adopting the procedures of three-roller planetary rolling, combined drawing, disc drawing and the like.

8) Testing the tube blank of the rare earth heat pipe: after high-temperature sintering at 980 ℃ for 3 hours, the grain size is observed by a metallographic microscope and EBSD; observing precipitated phases in the rare earth heat pipe through a transmission electron microscope; after sintering, bending and flattening tests are carried out, and the surface roughness of the sintered ceramic is tested by a laser confocal microscope.

The thickness of the charcoal and the graphite flakes in the S1) is 50-80 cm, and the mass ratio of the charcoal to the graphite flakes is 1: 1, graphite flakes are arranged on the upper part of charcoal, and the charcoal is replaced every 1.5 to 2 hours.

The content of P in the oxidation slag-off in S2) is reduced to be less than 20 ppm.

The said method of diluting with purified copper further reduces the P content to less than 10 ppm.

The intermediate alloy in the S3) is a rare earth intermediate alloy, the traction speed of the copper pipe is 200-400 mm/min, the melt temperature of the casting furnace is 1160-1180 ℃, the diameter of the cast pipe blank is phi 92-25 mm, and the wall thickness is 24-25 mm.

The rare earth lanthanum content in the rare earth intermediate alloy is 10-20%, and the weight of the added intermediate alloy is 1-1.5 kg.

The content of the rare earth lanthanum tested in the S4) is 30-70 ppm.

The grain size of the high-temperature-resistant rare earth heat pipe blank prepared in the S5) is 50-100 mu m after high-temperature sintering at 880-980 ℃ for 2-3 hours; and after sintering, bending and flattening tests show that the surface roughness of the sintered ceramic is 2000-3000 nm.

The high-temperature-resistant rare earth heat pipe blank is prepared by the method.

Example 1

The preparation process comprises the following steps: heating and melting an electrolytic copper plate, continuously adding the copper plate to 10 tons, and controlling the temperature of the melt to 1160 ℃.

Smelting protection, namely increasing the covering thickness of charcoal in a melting furnace and the covering thickness of graphite scales in a casting furnace, isolating air and preventing oxygen in the air from entering a copper melt. The thickness was 60cm and the charcoal was replaced every two 1.5 hours.

The furnace washing mainly reduces the phosphorus content, firstly reduces the phosphorus content to 20ppm by adopting an oxidation slag-off method in a melting furnace, and then controls the phosphorus content in the melting furnace and a casting furnace to 9ppm by a continuous dilution method.

The content of O, P is monitored on line, and when the content is less than 10ppm, the rare earth master alloy is started to be added. The rare earth master alloy is added in the following way: the rare earth lanthanum content in the rare earth intermediate alloy is 15%, 12 kg of intermediate alloy is added according to 14 tons of copper melt, 2 kg of single piece of intermediate alloy is added, the melting furnace is added before liquid is converted for 10 minutes in each furnace, about 1 ton of copper liquid is converted in each furnace, and 4 kg, 2 kg and 2 kg of intermediate alloy are sequentially added for four times. Considering 30% burning loss, the rare earth lanthanum content is expected to be 90 ppm. Before adding, the intermediate alloy is baked for 40 minutes at 500 ℃.

And horizontally and continuously casting and drawing a copper pipe casting blank, wherein the drawing speed of the copper pipe is 300mm/min, the melt temperature of the casting furnace is increased to 1165 ℃, and the copper pipe casting blank with the diameter phi of 92mm and the wall thickness of 25mm is continuously cast.

And (3) monitoring the rare earth content of the casting blank on line through ICP (inductively coupled plasma), wherein the rare earth lanthanum content in the casting blank is 75 ppm.

The finished product of the electronic rare earth heat pipe blank with the diameter of 8mm and the wall thickness of 0.3mm is obtained by adopting the procedures of three-roller planetary rolling, combined drawing, disc drawing and the like.

Testing the tube blank of the rare earth heat pipe: after high-temperature sintering at 980 ℃ for 3 hours, the microstructure of a rare earth tube containing 75ppm is observed through a metallographic microscope, the grain size is 50 microns, compared with a common pure copper tube without rare earth (the grain size is 200 microns), the grain size is reduced by 1/4, and the growth of the high-temperature sintering crystal grains of the pure copper tube can be obviously inhibited by adding rare earth; observing the precipitation of the rare earth phase in the sintered rare earth heat pipe on goldenrain tree grain boundaries through a transmission electron microscope, as shown in FIG. 5, which also illustrates the reason why the rare earth addition inhibits the grain growth; after sintering, bending and flattening tests show that the surface roughness is 2467nm through a laser confocal microscope test, and compared with a common pure copper pipe (the surface roughness is 4911nm), the surface roughness is obviously improved, as shown in figure 1, the microstructure after sintering without adding a rare earth heat pipe is shown, and as shown in figure 2, the microstructure after sintering with adding a rare earth heat pipe is shown.

Example 2

The difference from the embodiment 1 is that:

the preparation process comprises the following steps: heating and melting an electrolytic copper plate, continuously adding the copper plate to 8 tons, and controlling the temperature of the melt to 1165 ℃.

Smelting protection, namely increasing the covering thickness of charcoal in a melting furnace and the covering thickness of graphite scales in a casting furnace, isolating air and preventing oxygen in the air from entering a copper melt. The thickness was 70cm and the charcoal was replaced every two 2 hours.

The furnace washing mainly reduces the phosphorus content, firstly reduces the phosphorus content to 18ppm by adopting an oxidation slag-off method in a melting furnace, and then controls the phosphorus content in the melting furnace and a casting furnace to 8ppm by a continuous dilution method.

The content of O, P is monitored on line, and when the content is less than 10ppm, the rare earth master alloy is started to be added. The rare earth master alloy is added in the following way: the rare earth lanthanum content in the rare earth intermediate alloy is 20%, 3 kg of intermediate alloy is added according to 10 tons of copper melt, the weight of a single piece of the intermediate alloy is 1.5 kg, the intermediate alloy is added before 10 minutes of liquid rotation in each furnace of a melting furnace, the amount of the copper liquid is about 1 ton per furnace, and the amount of the intermediate alloy added for four times is 1.5 kg and 1.5 kg respectively. Considering 30% burning loss, the rare earth lanthanum content is expected to be 42 ppm. Before adding, the intermediate alloy is baked for 30 minutes at 400 ℃.

And horizontally and continuously casting and drawing a copper pipe casting blank, wherein the drawing speed of the copper pipe is 400mm/min, the melt temperature of the casting furnace is increased to 1160 ℃, and the copper pipe casting blank with the diameter phi of 94mm and the wall thickness of 24mm is continuously cast.

And (3) monitoring the rare earth content of the casting blank on line through ICP, wherein the rare earth lanthanum content in the casting blank is 34 ppm.

The finished product of the electronic rare earth heat pipe blank with the diameter of 6mm and the wall thickness of 0.2mm is obtained by adopting the procedures of three-roller planetary rolling, combined drawing, disk drawing and the like.

Testing the tube blank of the rare earth heat pipe: after high-temperature sintering at 980 ℃ for 3 hours, the structure of a rare earth tube containing 34ppm is observed through a metallographic microscope, the grain size is 100 microns, compared with a common pure copper tube without rare earth (the grain size is 200 microns), the grain size is reduced by 1/2, and the growth of the high-temperature sintering crystal grains of the pure copper tube can be obviously inhibited by adding rare earth; through further observation of EBSD, the crystal grains are obviously refined after the rare earth is added. After sintering, bending and flattening tests are carried out, the surface roughness is 2719nm through a laser confocal microscope test, and as shown in fig. 6, the shape and the appearance of the EBSD microstructure after sintering by the heat pipe without adding rare earth are shown. As shown in fig. 7, the shape and appearance of the EBSD microstructure after sintering by adding the rare earth heat pipe is shown to be improved significantly compared with the common pure copper pipe (the surface roughness is 4911nm), as shown in fig. 3, the microstructure after sintering by adding no rare earth heat pipe is shown, and as shown in fig. 4, the microstructure after sintering by adding the rare earth heat pipe is shown.

The embodiment result shows that the method can inhibit the grain growth problem of the heat pipe in the high-temperature sintering process, and further solve the problem of surface roughening defects of bending and flattening processes after the heat pipe is sintered, so that the rare earth heat pipe blank prepared by the method has good surface quality after being sintered, bent and flattened, and meets the processing requirements of high-precision heat pipe materials.

The embodiment of the present application provides a high temperature resistant rare earth heat pipe blank and a method for manufacturing the same, which are described in detail above. The above description of the embodiments is only for the purpose of helping to understand the method of the present application and its core ideas; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

As used in the specification and claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect. The description which follows is a preferred embodiment of the present application, but is made for the purpose of illustrating the general principles of the application and not for the purpose of limiting the scope of the application. The protection scope of the present application shall be subject to the definitions of the appended claims.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a commodity or system that includes the element.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The foregoing description shows and describes several preferred embodiments of the present application, but as aforementioned, it is to be understood that the application is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the application as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the application, which is to be protected by the claims appended hereto.