CN112371752B - Processing and preparation method of ultrathin-wall copper pipe - Google Patents
Processing and preparation method of ultrathin-wall copper pipe Download PDFInfo
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- CN112371752B CN112371752B CN202011121677.2A CN202011121677A CN112371752B CN 112371752 B CN112371752 B CN 112371752B CN 202011121677 A CN202011121677 A CN 202011121677A CN 112371752 B CN112371752 B CN 112371752B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
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Abstract
The invention belongs to the field of preparation of heat-conducting copper pipes, and particularly relates to a processing and preparation method of an ultrathin-wall copper pipe. The method comprises the following steps: 100 Pre-treating the copper tube blank to obtain a wall thickness of b 0 mm of pre-copper pipe, b is more than or equal to 1.8 0 Less than or equal to 2.5;200 P. pre-copperMaking a head on the tube, then utilizing an outer die and a core head to install a pre-copper tube, adding lubricating oil into a die forming cavity to draw the pre-copper tube to obtain an ultrathin-wall copper tube, and processing the ultrathin-wall copper tube until the copper tube meets the size requirement phi a f ×b f mm wherein a f Outer diameter of ultra-thin wall copper tube, b f The thickness of the tube wall of the ultra-thin copper tube, and b f Less than or equal to 0.15. The method can effectively prepare the ultrathin-wall copper pipe with the pipe wall thickness of 0.08-0.15 mm; the ultra-thin wall copper pipe has high product percent of pass, the hundred meter processing fracture rate can be controlled to be below 0.1 percent, and the ultra-thin wall copper pipe has practical production and processing values.
Description
Technical Field
The invention belongs to the field of heat conduction copper pipe preparation, and particularly relates to a processing and preparation method of an ultrathin-wall copper pipe.
Background
Copper tube heat dissipation is the most common heat dissipation means in the existing electronic devices, and is widely used in mobile phones, portable computers and high-power high-performance computer devices. The principle of copper pipe heat dissipation is that the good heat conductivity of the copper pipe and the condensation change of liquid in the copper pipe are utilized to realize phase change heat transfer, so that heat generated by electronic equipment is quickly dissipated to the external environment.
The main functional part of copper tube heat radiation, heat conducting copper tube, also known as heat pipe, is mainly composed of main copper tube part, liquid absorption core on the inner wall of copper tube and axial steam channel. However, along with the development of intellectualization and miniaturization of electronic equipment, the electronic components are highly integrated in a tiny space, so that more demands are placed on the heat conduction copper pipe, and the most intuitive demand is reflected in the requirement on the miniaturization of the copper pipe except for ensuring the heat dissipation efficiency.
In order to meet the requirement of high-integration use of the existing electronic equipment, research and development personnel of all parties make excellent contribution to the miniaturization of the heat conduction copper pipe, and the ultrathin heat conduction copper pipe with the pipe body thickness within 2mm can be realized at present. However, even in such a case, the speed of increasing the degree of integration in the electronic device is not as high as that of the electronic device, so that the heat conducting copper tube occupies a large space in the electronic device, and the negative limitation and limitation on the integration of the electronic device are formed. If the thickness of the ultra-thin heat conducting copper pipe is further reduced, the problem to be solved is to reduce the wall thickness of the heat conducting copper pipe.
The wall thickness of the existing ultrathin heat conduction copper pipe is usually about 0.3mm, and the wall thickness of the existing ultrathin heat conduction copper pipe with a better part can be reduced to about 0.25mm, but the existing ultrathin heat conduction copper pipe is difficult to further reduce, and the reduction of the wall thickness can greatly increase the processing difficulty of the heat conduction copper pipe and reduce the product yield. For example, when a heat conduction copper pipe with a pipe wall thickness of 0.3mm is processed and prepared by the prior art, the one hundred meter processing fracture rate can be controlled to be below 0.01%, when the heat conduction copper pipe with the pipe wall thickness of 0.25mm is processed and prepared, the one hundred meter processing fracture rate can be increased to about 0.05%, and when the heat conduction copper pipe with the pipe wall thickness of 0.15mm is further processed and prepared, the one hundred meter processing fracture rate can be increased to about 6%. And every time when the processing is broken, the machine needs to be stopped and restarted after the parameters of the equipment are adjusted, so that the processing efficiency is very low, the actual yield is very low, and the normal production and sale are completely difficult to realize.
In contrast, CN201310712500.3, a processing process flow of a copper tube for an ultra-thin wall air conditioner, discloses a technical scheme for implementing thin-walled preparation of a heat-conducting copper tube by using methods such as casting, surface milling, rolling, combined drawing, tray drawing, finishing, annealing, and the like. However, according to the technical scheme, through practical inspection, when the heat conduction copper pipe with the pipe wall thickness of 0.2mm is prepared and processed, the practical hundred-meter processing fracture rate reaches about 0.3%, when the heat conduction copper pipe with the pipe wall thickness of 0.15mm is prepared and processed, the hundred-meter processing fracture rate reaches about 5%, and normal production and sale are still difficult to meet, so that a larger improvement space still exists.
The wall thickness of the copper pipe is reduced, the plastic deformation capability is poor, and repeated annealing treatment is required. Meanwhile, the processing yield of the ultrathin copper pipe is low, and the precision is poor. The yield of the ultrathin tube produced by the common process is extremely low when the heat tube is manufactured, and the requirement of high-end electronic products is difficult to meet. The research of the technical personnel of the invention shows that the existing ultrathin-wall heat-conducting copper pipe has high production fracture rate, which is mainly caused by crystal defects and residual stress generated in the drawing process.
Disclosure of Invention
The invention provides a processing and preparation method of an ultrathin-wall copper pipe, aiming at solving the problem that the existing copper pipe is difficult to adapt to highly integrated electronic equipment and the contradiction that the size of the whole heat-conducting copper pipe is reduced by reducing the wall thickness of the copper pipe is urgently needed because an effective and practical production value-possessing technical scheme for preparing the ultrathin-wall copper pipe with the pipe wall thickness of 0.15mm or less does not exist at present. The invention aims to:
1. the copper pipe with the pipe wall thickness of 0.15mm or less is effectively prepared;
2. the defects of the copper pipe are reduced, the yield of the ultrathin-wall copper pipe is improved, and the processing fracture rate of the ultrathin-wall copper pipe is reduced.
In order to achieve the purpose, the invention adopts the following technical scheme.
A method for processing and preparing an ultra-thin wall copper tube,
the method comprises the following steps:
100 Pre-treating the copper tube blank to obtain a wall thickness of b 0 mm，b 0 ≤0.3；
200 Manufacturing a head on the copper pre-tube, then utilizing an outer die and a core head to install the copper pre-tube, adding lubricating oil into a die forming cavity to perform drawing to obtain an ultra-thin-wall copper tube, and processing until the copper tube meets the size requirement phi a f ×b f mm wherein a f Outer diameter of ultra-thin wall copper tube, b f The thickness of the tube wall of the ultra-thin copper tube, and b f ≤0.15。
The invention requires that the oxygen content of the copper pipe parent metal is not more than 10ppm. In the method, the drawing process is regulated and controlled by prefabricating and drawing processing and matching with a finite element fitting control system, so that the preparation and processing of the ultrathin-wall copper pipe with the pipe wall thickness of less than or equal to 0.15mm are realized.
As a preference, the first and second liquid crystal compositions are,
the pretreatment in the step 100) comprises cleaning, rolling and combined drawing;
the cleaning comprises polishing, descaling and degreasing;
the rolling is carried out by a three-roller planetary rolling mill;
and the combined drawing adopts a clamp to clamp for carrying out the triple drawing.
The above processes are all well-established, common and commonly used processing and preparation pretreatment processes, and can effectively realize the rapid pretreatment of the copper pipe blank to obtain the pipe material for processing.
As a preference, the first and second liquid crystal compositions are,
and 200) the surfaces of the outer die and the core print are made of Ti (CN) metal ceramic materials.
Compared with the existing external mold and core print made of alloy components such as chromium steel, carbon steel, titanium nitride and the like, the invention adopts special titanium carbonitride cermet material as the surface of the external mold and the core print and the part which is in direct contact with the pre-copper pipe. It is specifically Ti 10 C 7 N 3 The titanium nitride/titanium carbide composite material is a zero-dimensional ternary solid solution, a metal ceramic composite layer is formed on the surface of an outer die or a core head in common modes such as powder spraying and ultrahigh-sound-speed flame spraying, has the advantages of both titanium nitride and titanium carbide, has high melting point, high hardness, excellent wear resistance, oxidation resistance and corrosion resistance, has good chemical stability, and simultaneously has good thermal conductivity, particularly has excellent self-lubricating characteristics, and can reduce the friction force in the processing process. And due to the particularity of the crystal structure of the copper tube, the copper tube is not easy to fall off to form impurities to be introduced into the heat conduction copper tube.
As a preference, the first and second liquid crystal compositions are,
step 200) performing mirror polishing on the surfaces of the outer die and the core print, wherein the curvature change of the polished surfaces meets the parabolic rule;
the friction coefficient between the outer die and the outer wall of the pre-copper pipe is controlled to be less than or equal to 0.10;
the friction coefficient between the core print and the inner wall of the pre-copper pipe is controlled to be less than or equal to 0.04.
After mirror polishing, the roughness of the surfaces of the outer die and the core head can be effectively controlled, and the friction coefficient between the outer die and the outer wall of the pre-copper pipe and the friction coefficient between the core head and the inner wall of the pre-copper pipe are controlled by matching with lubricating oil. Practical experiments show that when the friction coefficient between the outer die and the outer wall of the pre-copper pipe is less than or equal to 0.10, the outer die and the pre-copper pipe can be ensured to generate axial deviation only in a small range of less than 0.05mm in the drawing process, and when the friction coefficient between the core print and the inner wall of the pre-copper pipe is less than or equal to 0.04, the core print and the pre-copper pipe can be ensured to generate axial deviation only in a range of less than 0.15mm in the drawing process. Axial offset refers to the deviation from the theoretical relative position, not the relative displacement value.
As a preference, the first and second liquid crystal compositions are,
the friction coefficient between the core print and the inner wall of the pre-copper pipe is 0.02-0.03.
When the friction coefficient between the core print and the inner wall of the pre-copper pipe is accurate to be between 0.02 and 0.03, the axial offset between the core print and the inner wall of the pre-copper pipe can be reduced within an ultra-small range of 0.03mm, the problem of uneven drawing of the copper pipe caused by the axial offset is reduced, the uniformity of the wall thickness is improved, the equivalent stress range and the equivalent strain range of the pre-copper pipe in the drawing process are reduced, and the fracture protection is realized. When the friction coefficient is too small, the axial shift is liable to increase.
As a matter of preference,
and 200) drawing in a sectional type, wherein the drawing is carried out in an alternate mode of fixed drawing and moving drawing.
The fixed drawing in the invention refers to the drawing of the fixed short core print, but not the drawing of the long core print. In the conventional drawing process, the fixed drawing mainly realizes the effects of rapid growth and wall thickness reduction, and the floating drawing is less efficient than the fixed drawing, but can generally better avoid the problem of drawing fracture. The invention discovers that the actually generated radial residual stress is smaller and even generates a certain negative value in the fixed drawing process, and the axial residual stress of the floating drawing is smaller and generates a certain negative value, so that the residual stress generated in the drawing process is reduced by creatively adopting a combined mode. In addition, compared with the fixed drawing of the long core head, the cooperative effect of the fixed drawing and the moving drawing of the short core head is better, and the method is different from the widely-considered drawing of the long core head which is superior to the drawing of the short core head.
As a preference, the first and second liquid crystal compositions are,
the sectional drawing is firstly used for drawing the thickness of the pipe wall to b by adopting fixed drawing 1 mm, followed by free drawing to tube wall thicknessDegree b 2 mm, repeating and sequentially carrying out fixed drawing and moving drawing circulation for n times in total;
sequentially drawing the tube wall from b in a sectional type 0 mm is drawn to b 1 mm、b 2 mm……b 2n-1 mm、b 2n mm, final thickness of the pipe wall of b 2n moving and drawing when mm is reached to the pipe wall thickness of b f mm。
The alternate and repeated fixed drawing and floating drawing can effectively reduce the residual stress in the drawing process, and simultaneously, the wall thickness of the tube is controlled to form step-type reduction, thereby being beneficial to reducing the copper tube fracture caused by the drawing process.
As a preference, the first and second liquid crystal compositions are,
when the drawing is performed for the mth time in the sectional drawing, m is more than or equal to 1 and less than or equal to n;
when | b m-1 -b m |≤b m-1 X 40%, and directly carrying out subsequent operations;
when | b 2m-1 -b 2m |＞b 2m-1 X 40%, and carrying out complete annealing treatment, wherein the complete annealing treatment comprises the following steps: the annealing temperature is 300-350 ℃, the heat preservation time is 2-3 h, the whole annealing process is carried out in a protective atmosphere, and the annealing is discharged after being cooled to below 50 ℃ along with the furnace;
the drawing speed of the fixed drawing in the sectional drawing is 10-40 m/min;
the drawing speed of the moving drawing in the sectional drawing is 10-20 m/min;
after the sectional drawing is finished, the thickness of the tube wall is b 2n moving and drawing the mm copper pipe to the thickness of the pipe wall of b f When mm, the drawing speed is 4-6 m/min.
In the above solution, the purpose of the fixed drawing and the travelling drawing is different. The fixed drawing mainly plays a role in reducing the thickness of the tube wall, and the floating drawing plays a role in stabilizing the structure of the copper tube to a greater extent, so that the copper tube is prevented from generating stress fracture. So that | b should be optimally controlled 2m-1 -b 2m |≤b 2m-1 X 20%. And after the final sectional drawing is finished, further adopting the traveling drawing with extremely low drawing speed to avoid generating larger radial drawingResidual stress and final thinning of the tube wall. Complete annealing treatment at b 2m-1 -b 2m |＞b 2m-1 X 40% must be processed, while at b 2m-1 -b 2m |＞b 2m-1 X 20% is optionally performed. As a preference, the first and second liquid crystal compositions are,
step 200) the drawing process adopts finite element fitting control, and the finite element fitting control steps are as follows:
201 Drawing model establishment: firstly, selecting drawing conditions, such as positioning deviation parameters of an outer die, a core print, the core print and the axis of a pre-copper pipe, analyzing and summarizing the existing mechanical model, setting a drawing range according to the mechanical model, and performing error comparison in the drawing range, so as to screen out an optimal drawing model under the fixed drawing conditions;
202 Analysis of deformation rule of pre-copper tube: based on the optimal drawing model screened in the step 201), establishing a finish Element Analysis model of the drawing deformation of the pre-copper pipe, carrying out deformation Analysis by using ANSYS according to the size change before and after drawing, and analyzing the drawing deformation change rule according to different working conditions to obtain a typical pre-copper pipe deformation change rule, namely a Finite Element Analysis result;
203 Verification of the Finite Element Analysis model built according to ANSYS: carrying out multiple groups of experiments on a copper sample, comparing the results with the Finite Element Analysis results obtained in the step 202), fitting the data, analyzing the multiple groups of experimental data, and verifying the Finite Element Analysis model established in the step 202);
204 If the finished Element Analysis model in the step 203) is verified to be qualified through the detection of multiple groups of experimental data, the drawing processing step is carried out, and if the finished Element Analysis model is not qualified, the step is returned to the step 201).
The optimal operation parameters suitable for drawing the current copper material to the required size can be effectively screened out through finite element fitting control, and the preparation efficiency of the ultrathin-wall copper pipe can be effectively improved.
As a preference, the first and second liquid crystal compositions are,
and step 201), the positioning deviation between the core print and the axle center of the pre-copper pipe is less than or equal to 0.01mm.
The positioning deviation between the core print and the axis of the pre-copper pipe is reduced, the wall thickness uniformity of the manufactured ultra-thin wall copper pipe can be further improved, and the radial residual stress is reduced.
The invention has the beneficial effects that:
1) The ultrathin-wall copper pipe with the pipe wall thickness of 0.08-0.15 mm can be effectively prepared;
2) The product percent of pass of the ultrathin-wall copper pipe is high, the hundred-meter processing fracture rate can be controlled to be below 0.1 percent, and the ultrathin-wall copper pipe has practical production and processing values.
Drawings
FIG. 1 is a graph of axial deflection of a mandrel versus time under the influence of a coefficient of friction.
Detailed Description
The invention is described in further detail below with reference to specific embodiments and the attached drawing figures. Those skilled in the art will be able to implement the invention based on these teachings. Furthermore, the embodiments of the present invention described in the following description are generally only a part of the embodiments of the present invention, and not all of the embodiments. Therefore, all other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.
Unless otherwise specified, all the raw materials used in the examples of the present invention are commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all those known to those skilled in the art.
The hundred meter work breakage Rate (D) described in the present specification unless otherwise specified 100 ) Is calculated by the formula D 100 And (b) = (a/100) × 100%, wherein a is the number of times of fracture of a finished heat conduction copper pipe of 100m obtained by each processing preparation.
If not stated otherwise, the copper pipe blanks are all prepared by copper pipe base metal with oxygen content less than 10ppm.
Example 1
A processing and preparation method of an ultrathin-wall copper tube is characterized in that,
the method comprises the following steps:
100 Carrying out pretreatment such as polishing, descaling, degreasing, rolling by a three-roller planetary mill, and triple drawing by clamping by a clamp on the copper pipe blank to obtain a pre-copper pipe with phi 12 multiplied by 0.3 mm;
200 Manufacturing heads on the pre-copper pipe, then utilizing an outer die and a core head with surfaces made of Ti (CN) cermet materials to install the pre-copper pipe, coating lubricating oil on the inner wall and the outer wall of the pre-copper pipe, and drawing to obtain the ultrathin-wall copper pipe, wherein the obtained ultrathin-wall copper pipe meets the size requirement phi 5 multiplied by 0.15mm.
The remaining specific preparation parameters of this example are as follows:
the friction coefficient between the outer die and the outer wall of the pre-copper pipe is 0.10, and the friction coefficient between the core print and the inner wall of the pre-copper pipe is 0.04;
a total of five cycles of fixed and floating pulls were carried out, the specific parameters being shown in the following table:
| thickness of pipe wall | Drawing speed | Thickness of pipe wall | Drawing speed | ||
| b1 | 0.225mm | 40m/min | b2 | 0.22mm | 20m/min |
| b3 | 0.20mm | 35m/min | b4 | 0.19mm | 20m/min |
| b5 | 0.185mm | 30m/min | b6 | 0.18mm | 15m/min |
| b7 | 0.175mm | 20m/min | b8 | 0.17mm | 10m/min |
| b9 | 0.165mm | 10m/min | b10 | 0.16mm | 10m/min |
And finally, performing traveling drawing at the drawing speed of 6m/min until the thickness of the pipe wall is 0.15mm after the sectional drawing.
Wherein, in the sectional drawing, the complete annealing treatment is carried out after the first fixed drawing (b 1) is finished, and the conditions of the complete annealing treatment are as follows: the annealing temperature is 300 ℃, the heat preservation time is 2 hours, the whole annealing process is carried out in the nitrogen atmosphere, the annealing is cooled to below 50 ℃ along with the furnace, then the annealing is discharged, and the first moving drawing (b 2) is carried out.
Example 2
A processing and preparation method of an ultra-thin wall copper pipe is characterized in that,
the method comprises the following steps:
100 Carrying out pretreatment such as polishing, descaling, degreasing, rolling by a three-roller planetary mill, and triple drawing by clamping by a clamp on the copper pipe blank to obtain a pre-copper pipe with phi 12 multiplied by 0.3 mm;
200 Manufacturing heads on the pre-copper pipe, then utilizing an outer die and a core head with surfaces made of Ti (CN) cermet materials to install the pre-copper pipe, coating lubricating oil on the inner wall and the outer wall of the pre-copper pipe, and drawing to obtain the ultrathin-wall copper pipe, wherein the obtained ultrathin-wall copper pipe meets the size requirement phi 5 multiplied by 0.15mm.
The remaining specific preparation parameters of this example are as follows:
the friction coefficient between the outer die and the outer wall of the pre-copper pipe is 0.10, and the friction coefficient between the core print and the inner wall of the pre-copper pipe is 0.03; a total of five cycles of fixed and floating pulls were carried out, the specific parameters being shown in the following table:
| thickness of pipe wall | Drawing speed | Thickness of pipe wall | Drawing speed | ||
| b1 | 0.225mm | 40m/min | b2 | 0.22mm | 20m/min |
| b3 | 0.20mm | 35m/min | b4 | 0.19mm | 20m/min |
| b5 | 0.185mm | 30m/min | b6 | 0.18mm | 15m/min |
| b7 | 0.175mm | 20m/min | b8 | 0.17mm | 10m/min |
| b9 | 0.165mm | 10m/min | b10 | 0.16mm | 10m/min |
And finally, performing traveling drawing at the drawing speed of 6m/min until the thickness of the pipe wall is 0.15mm after the sectional drawing.
Wherein, in the sectional drawing, the complete annealing treatment is carried out after the first fixed drawing (b 1) is finished, and the conditions of the complete annealing treatment are as follows: the annealing temperature is 300 ℃, the heat preservation time is 2 hours, the whole annealing process is carried out in the nitrogen atmosphere, the annealing is cooled to below 50 ℃ along with the furnace, then the annealing is discharged, and the first moving drawing (b 2) is carried out.
Example 3
A processing and preparation method of an ultrathin-wall copper tube is characterized in that,
the method comprises the following steps:
100 Carrying out pretreatment such as polishing, descaling, degreasing, rolling by a three-roller planetary mill, and triple drawing by clamping by a clamp on the copper pipe blank to obtain a pre-copper pipe with phi 12 multiplied by 0.3 mm;
200 Manufacturing heads on the pre-copper pipe, then utilizing an outer die and a core head with surfaces made of Ti (CN) cermet materials to install the pre-copper pipe, coating lubricating oil on the inner wall and the outer wall of the pre-copper pipe, and drawing to obtain the ultrathin-wall copper pipe, wherein the obtained ultrathin-wall copper pipe meets the size requirement phi 5 multiplied by 0.15mm.
The remaining specific preparation parameters of this example are as follows:
the friction coefficient between the outer die and the outer wall of the pre-copper pipe is 0.10, and the friction coefficient between the core print and the inner wall of the pre-copper pipe is 0.02;
five cycles of fixed and floating pulls were performed in total, the specific parameters being shown in the table below:
| thickness of pipe wall | Drawing speed | Thickness of pipe wall | Drawing speed | ||
| b1 | 0.225mm | 40m/min | b2 | 0.22mm | 20m/min |
| b3 | 0.20mm | 35m/min | b4 | 0.19mm | 20m/min |
| b5 | 0.185mm | 30m/min | b6 | 0.18mm | 15m/min |
| b7 | 0.175mm | 20m/min | b8 | 0.17mm | 10m/min |
| b9 | 0.165mm | 10m/min | b10 | 0.16mm | 10m/min |
And finally, performing traveling drawing at the drawing speed of 6m/min until the thickness of the pipe wall is 0.15mm after the sectional drawing.
Wherein, in the sectional drawing, the complete annealing treatment is carried out after the first fixed drawing (b 1) is finished, and the conditions of the complete annealing treatment are as follows: the annealing temperature is 300 ℃, the heat preservation time is 2 hours, the whole annealing process is carried out in the nitrogen atmosphere, the annealing is cooled to below 50 ℃ along with the furnace, then the annealing is discharged, and the first moving drawing (b 2) is carried out.
Example 4
A processing and preparation method of an ultra-thin wall copper pipe is characterized in that,
the method comprises the following steps:
100 Carrying out pretreatment such as polishing, descaling, degreasing, rolling by a three-roller planetary mill, and triple drawing by clamping by a clamp on the copper pipe blank to obtain a pre-copper pipe with phi 12 multiplied by 0.3 mm;
200 Manufacturing heads on the pre-copper pipe, then utilizing an outer die and a core head with surfaces made of Ti (CN) cermet materials to install the pre-copper pipe, coating lubricating oil on the inner wall and the outer wall of the pre-copper pipe, and drawing to obtain the ultrathin-wall copper pipe, wherein the obtained ultrathin-wall copper pipe meets the size requirement phi 5 multiplied by 0.15mm.
The remaining specific preparation parameters of this example are as follows:
the friction coefficient between the outer die and the outer wall of the pre-copper pipe is 0.10, and the friction coefficient between the core print and the inner wall of the pre-copper pipe is 0.01;
five cycles of fixed and floating pulls were performed in total, the specific parameters being shown in the table below:
| thickness of pipe wall | Drawing speed | Thickness of pipe wall | Drawing speed | ||
| b1 | 0.225mm | 40m/min | b2 | 0.22mm | 20m/min |
| b3 | 0.20mm | 35m/min | b4 | 0.19mm | 20m/min |
| b5 | 0.185mm | 30m/min | b6 | 0.18mm | 15m/min |
| b7 | 0.175mm | 20m/min | b8 | 0.17mm | 10m/min |
| b9 | 0.165mm | 10m/min | b10 | 0.16mm | 10m/min |
And finally, performing traveling drawing at the drawing speed of 6m/min until the thickness of the pipe wall is 0.15mm after the sectional drawing.
Wherein in the sectional type drawing, the complete annealing treatment is carried out after the first fixed drawing (b 1) is finished, and the complete annealing treatment conditions are as follows: the annealing temperature is 300 ℃, the heat preservation time is 2 hours, the whole annealing process is carried out in the nitrogen atmosphere, the annealing is cooled to below 50 ℃ along with the furnace, then the annealing is discharged, and the first moving drawing (b 2) is carried out.
Example 5
A processing and preparation method of an ultra-thin wall copper pipe is characterized in that,
the method comprises the following steps:
100 Carrying out pretreatment such as polishing, descaling, degreasing, rolling by a three-roller planetary mill, and triple drawing by clamping by a clamp on the copper pipe blank to obtain a pre-copper pipe with phi 12 multiplied by 0.5 mm;
200 Manufacturing heads on the pre-copper pipe, then utilizing an outer die and a core head with surfaces made of Ti (CN) cermet materials to install the pre-copper pipe, coating lubricating oil on the inner wall and the outer wall of the pre-copper pipe, and drawing to obtain the ultrathin-wall copper pipe, wherein the obtained ultrathin-wall copper pipe meets the size requirement phi 5 multiplied by 0.15mm.
The remaining specific preparation parameters of this example are as follows:
the friction coefficient between the outer die and the outer wall of the pre-copper pipe is 0.10, and the friction coefficient between the core print and the inner wall of the pre-copper pipe is 0.04;
a total of five cycles of fixed and floating pulls were carried out, the specific parameters being shown in the following table:
| thickness of pipe wall | Drawing speed | Thickness of pipe wall | Drawing speed | ||
| b1 | 0.3mm | 40m/min | b2 | 0.29mm | 20m/min |
| b3 | 0.25mm | 35m/min | b4 | 0.24mm | 20m/min |
| b5 | 0.22mm | 30m/min | b6 | 0.21mm | 15m/min |
| b7 | 0.18mm | 20m/min | b8 | 0.17mm | 10m/min |
| b9 | 0.165mm | 10m/min | b10 | 0.15mm | 10m/min |
And finally, performing traveling drawing at the drawing speed of 6m/min until the thickness of the pipe wall is 0.15mm after the sectional drawing.
Wherein, in the sectional drawing, the complete annealing treatment is carried out after the first fixed drawing (b 1) is finished, and the conditions of the complete annealing treatment are as follows: the annealing temperature is 300 ℃, the heat preservation time is 2 hours, the whole annealing process is carried out in the nitrogen atmosphere, the annealing is cooled to below 50 ℃ along with the furnace, then the annealing is discharged, and the first moving drawing (b 2) is carried out.
Example 6
A processing and preparation method of an ultrathin-wall copper tube is characterized in that,
the method comprises the following steps:
100 Carrying out pretreatment such as polishing, descaling, degreasing, rolling by a three-roller planetary mill, and triple drawing by clamping by a clamp on the copper pipe blank to obtain a pre-copper pipe with phi 12 multiplied by 0.3 mm;
200 Manufacturing heads on the pre-copper pipe, then utilizing an outer die and a core head with surfaces made of Ti (CN) cermet materials to install the pre-copper pipe, coating lubricating oil on the inner wall and the outer wall of the pre-copper pipe, and drawing to obtain the ultra-thin wall copper pipe, wherein the ultra-thin wall copper pipe meets the size requirement phi of 5 multiplied by 0.15mm.
The remaining specific preparation parameters of this example are as follows:
the friction coefficient between the outer die and the outer wall of the pre-copper pipe is 0.10, and the friction coefficient between the core print and the inner wall of the pre-copper pipe is 0.04;
a total of three cycles of fixed and floating drawing were carried out, the specific parameters being shown in the following table:
| thickness of pipe wall | Drawing speed | Thickness of pipe wall | Drawing speed | ||
| b1 | 0.225mm | 30m/min | b2 | 0.22mm | 15m/min |
| b3 | 0.175mm | 25m/min | b4 | 0.17mm | 15m/min |
| b5 | 0.165mm | 20m/min | b6 | 0.16mm | 10m/min |
And finally, performing traveling drawing at the drawing speed of 6m/min until the thickness of the pipe wall is 0.15mm after the sectional drawing.
Wherein, the complete annealing treatment is carried out after the fixed drawing (b 1 and b 3) is finished in the sectional drawing, and the conditions of the complete annealing treatment are as follows: the annealing temperature is 350 ℃, the heat preservation time is 3 hours, the whole annealing process is carried out in a nitrogen atmosphere, the annealing is cooled to below 50 ℃ along with the furnace, then the annealing is discharged out of the furnace, and then the moving drawing (b 2 and b 4) is carried out.
Example 7
The specific operation was the same as example 1, except that the obtained ultra-thin wall copper tube satisfied the size Φ 3 × 0.1mm, and the specific parameters of the sectional drawing were as shown in the following table:
| thickness of pipe wall | Drawing speed | Thickness of pipe wall | Drawing speed | ||
| b1 | 0.225mm | 40m/min | b2 | 0.22mm | 20m/min |
| b3 | 0.18mm | 35m/min | b4 | 0.17mm | 20m/min |
| b5 | 0.16mm | 30m/min | b6 | 0.15mm | 15m/min |
| b7 | 0.14mm | 20m/min | b8 | 0.13mm | 10m/min |
| b9 | 0.12mm | 10m/min | b10 | 0.11mm | 10m/min |
And finally, performing traveling drawing at the drawing speed of 6m/min until the thickness of the pipe wall is 0.10mm after the sectional drawing.
Wherein, in the sectional drawing, the complete annealing treatment is carried out after the first fixed drawing (b 1) is finished, and the conditions of the complete annealing treatment are as follows: the annealing temperature is 300 ℃, the heat preservation time is 3 hours, the whole annealing process is carried out in the nitrogen atmosphere, the annealing is cooled to below 50 ℃ along with the furnace, then the annealing is discharged, and the first moving drawing (b 2) is carried out.
Example 8
The procedure is as in example 7, except that: and finally, performing traveling drawing at a drawing speed of 4m/min until the thickness of the pipe wall is 0.10mm after sectional drawing.
Example 9
The specific operation was the same as example 1, except that the obtained ultra-thin wall copper tube satisfied the size Φ 2 × 0.08mm, and the specific parameters of the sectional drawing were as shown in the following table:
| thickness of pipe wall | Drawing speed | Thickness of pipe wall | Drawing speed | ||
| b1 | 0.185mm | 30m/min | b2 | 0.18mm | 20m/min |
| b3 | 0.155mm | 25m/min | b4 | 0.15mm | 20m/min |
| b5 | 0.135mm | 20m/min | b6 | 0.13mm | 15m/min |
| b7 | 0.115mm | 20m/min | b8 | 0.11mm | 10m/min |
| b9 | 0.095mm | 10m/min | b10 | 0.09mm | 10m/min |
And finally performing traveling drawing at a drawing speed of 4m/min until the thickness of the pipe wall is 0.08mm after the sectional drawing.
Wherein, in the sectional drawing, the complete annealing treatment is carried out after the first fixed drawing (b 1) is finished, and the conditions of the complete annealing treatment are as follows: the annealing temperature is 300 ℃, the heat preservation time is 3h, the whole annealing process is carried out in the nitrogen atmosphere, the annealing is cooled to below 50 ℃ along with the furnace, and then the annealing is discharged and the first moving drawing (b 2) is carried out.
Example 10
The specific procedure was the same as in example 9, except that: the drawing process adopts finite element fitting control, and the finite element fitting control comprises the following steps:
201 Drawing model establishment: firstly, selecting drawing conditions, such as positioning deviation parameters of an outer die, a core print, the core print and the axis of a pre-copper pipe, wherein the positioning deviation parameters of the core print and the axis of the pre-copper pipe are less than or equal to 0.005mm, analyzing and summarizing the existing mechanical model, setting a drawing range according to the mechanical model, and performing error comparison in the drawing range, thereby screening out an optimal drawing model under the fixed drawing condition;
202 Analysis of deformation rule of pre-copper tube: based on the optimal drawing model screened in the step 201), establishing a finish Element Analysis model of the drawing deformation of the pre-copper pipe, carrying out deformation Analysis by using ANSYS according to the size change before and after drawing, and analyzing the drawing deformation change rule according to different working conditions to obtain a typical pre-copper pipe deformation change rule, namely a Finite Element Analysis result;
203 Verify the finish Element Analysis model built according to ANSYS: carrying out multiple groups of experiments on a copper sample, comparing the results with the Finite Element Analysis results obtained in the step 202), fitting the data, analyzing the multiple groups of experimental data, and verifying the Finite Element Analysis model established in the step 202);
204 If the finished Element Analysis model in the step 203) is verified to be qualified through the detection of multiple groups of experimental data, the drawing processing step is carried out, and if the finished Element Analysis model is not qualified, the step is returned to the step 201).
Comparative example 1
The specific procedure was the same as in example 1, except that: the sectional drawing is carried out in a fixed drawing mode.
Comparative example 2
The procedure is as in example 1, except that: the sectional drawing is carried out in a moving drawing mode.
Comparative example 3
The specific procedure was the same as in example 1, except that: and in the sectional drawing cycle, complete annealing treatment is not carried out after the first fixed drawing.
Comparative example 4
The specific procedure was the same as in example 1, except that: the friction coefficient between the core print and the inner wall of the pre-copper pipe is 0.05.
Comparative example 5
The specific procedure was the same as in example 1, except that: the outer die and the core print are both made of conventional chromium steel.
And recording and comparing the hundred-meter processing fracture rate and the product yield of the examples 1-10 and the comparative examples 1-5, wherein the product yield is detected by randomly selecting 20 measuring points for each hundred meters of products to measure the thickness of the measuring points and the wall thickness of the pipe, the difference between the thickness of the measuring result of at least 19 measuring points and the thickness in the calibration specification is less than 3%, and the difference between the wall thickness of the pipe and the wall thickness of the pipe in the calibration specification is less than 3%, and the pipe is marked as a good product. Since the comparative examples 1 to 5 are non-industrial production, only 1000 m copper tube processing preparation is carried out in each process for saving cost, the proportion of the measurement points meeting the standard is taken as the yield, and the daily production record of a factory is taken as data in the embodiment part.
The test results are reported in the table below.
| Test sample | D 100 | Yield of good products | Test sample | D 100 | Yield of good products |
| Example 1 | 0.092％ | 97.8％ | Example 9 | 0.099％ | 97.4％ |
| Example 2 | 0.031％ | 99.1％ | Example 10 | 0.091％ | 98.3％ |
| Example 3 | 0.029％ | 99.4％ | Comparative example 1 | 4.100％ | 76.5％ |
| Example 4 | 0.087％ | 99.4％ | Comparative example 2 | 5.200％ | 85.5％ |
| Example 5 | 0.094％ | 97.9％ | Comparative example 3 | 2.400％ | 96.0％ |
| Example 6 | 0.114％ | 95.5％ | Comparative example 4 | 1.100％ | 96.5％ |
| Example 7 | 0.106％ | 97.2％ | Comparative example 5 | 0.600％ | 89.0％ |
| Example 8 | 0.093％ | 98.2％ |
The data in the table above were analyzed. As is apparent from the comparison between example 1 and comparative examples 1 to 2, the fracture rate in the hundred-meter process is significantly improved by both the completely fixed drawing and the completely floating drawing. I.e., making the overall process difficult to perform efficiently, requiring frequent shutdowns. Compared with the data of the comparative example 1 and the comparative example 2, the fixed drawing is less prone to fracture compared with the moving drawing, and the stress analysis on the fixed drawing shows that the axial residual stress in the product of the comparative example 1 is greater than that of the comparative example 2, but the radial residual stress is significantly less than that of the comparative example 2, and both the axial residual stress and the radial residual stress of the comparative example 1 and the comparative example 2 are far greater than those of the example 1, so that the fracture of the comparative example 1 and the comparative example 2 is mainly caused by the residual stress generated in the drawing process, and the radial residual stress has a greater influence in the preparation of the ultrathin-wall copper pipe, but due to the characteristics of the moving drawing, the average pipe wall thickness and the copper pipe thickness of the product can be controlled more favorably in the drawing process, and the yield is higher than that of the comparative example 1. Further comparative examples 1 to 4. In examples 1 to 4, the friction coefficient between the core print and the inner wall of the pre-copper tube was gradually decreased, and the control was mainly performed by adding lubricating oil and the degree of surface polishing of the core print. And along with the reduction of the friction coefficient, the hectometer processing fracture rate is the trend that reduces earlier the increase later, and the yields is single growth trend, shows that lower friction coefficient is favorable to the promotion of yields, and the friction coefficient is less than 0.02 back and leads to the hectometer processing fracture rate to rise on the contrary easily, this is mainly because the axial excursion of core head in the copper pipe causes, and the axial excursion leads to stress concentration and then takes place the fracture easily. In addition, in comparison with the data of comparative example 4, comparative example 4 only increased the coefficient of friction to 0.05, which has resulted in a significant increase in the one hundred meter process breakage rate and a decrease in yield, again due to a dramatic increase in axial run out. It is evident from a comparison of examples 1, 5 and 6 that the pre-copper tubes, when adjusted within the specifications defined in the present invention, have negligible impact on the processing. Example 6 shows that simply reducing the number of cycles of the segmental drawing results in a hundred meter process with increased breakage and decreased yield, but is still more controllable, so that the number of cycles of the segmental drawing should be at least three cycles. While comparing with comparative example 3. Embodiment 6 reduces the number of cycles and increases the number of times of annealing treatment, still can keep lower hectometer processing fracture rate and higher yields, and comparative example 3 is under the condition of not carrying out annealing treatment completely, though the yields is slightly higher than embodiment 6, hectometer processing fracture rate is showing and is promoting, this is because the pipe wall thickness once has produced very big residual stress after thinning too much, leads to constantly breaking easily in the attenuate process of pipe wall thickness. Examples 7 and 8 show that when an ultrathin-wall copper pipe with a thinner pipe wall is processed and prepared, the reduction of the moving drawing speed after sectional drawing is more beneficial to reducing the hundred-meter processing fracture rate of the product and improving the yield to a certain extent. Examples 9 and 10 show that the use of finite element fit to control the drawing process is also optimized for reducing one hundred meter process breakage rate and product quality during the manufacturing process.
The comparative example 5 and the example 1 are different only in the material of the core print and the outer mold surface, which causes the difference of the processing and preparation processes. The processing fracture rate of hectometer is relatively controllable, but the yield rate is sharply reduced. The reason is that compared with the surface of Ti (CN) metal ceramic material used by the invention, the chromium steel is easier to form particle doping, which causes local change of the crystal structure and components of the tube wall, and the problem of uneven thickness is easy to occur in the preparation process of the ultra-thin copper tube.
The axial shift of the core print in the final floating drawing process of the examples 1 to 4 and the comparative example 4 was examined to obtain a graph of the axial shift of the core print as shown in fig. 1, as is apparent from the graph. The axial offset distances of the core prints of example 1 and example 4 are similar and are all in the range of about 0.12 to 0.14mm, while the axial offset distances of the core prints of example 2 and example 3 are all within about 0.02 to 0.03mm, and the axial offset distance of the core print of comparative example 4 is increased to about 0.3mm. Indicating the large effect of the coefficient of friction on axial deflection of the core print.
Claims (7)
1. A processing and preparation method of an ultrathin-wall copper tube is characterized in that,
the method comprises the following steps:
100 Pre-treating the copper tube base material to obtain a wall thickness of b 0 ，b 0 ≤0.3；
200 Heading a copper tube base material, then installing the copper tube base material by utilizing an outer die and a core head, adding lubricating oil into a die forming cavity for drawing to obtain an ultra-thin-wall copper tube, and processing until the copper tube meets the size requirementΦa f ×b f mm wherein a f Outer diameter of ultra-thin wall copper tube, b f The thickness of the tube wall of the ultra-thin wall copper tube, and b f ≤0.15；
Step 200) drawing is performed in a sectional drawing mode in an alternative mode of fixed drawing and moving drawing;
the sectional drawing is firstly used for drawing the thickness of the pipe wall to b by adopting fixed drawing 1 mm, followed by free drawing to a wall thickness of b 2 mm, repeating and sequentially carrying out fixed drawing and moving drawing circulation for n times in total;
sequentially drawing the tube wall from b in a sectional type 0 mm is drawn to b 1 mm、b 2 mm……b 2n-1 mm、b 2n mm, final thickness of the pipe wall of b 2n moving and drawing when mm is reached to the pipe wall thickness of b f mm；
When the drawing is performed for the mth time in the sectional drawing, m is more than or equal to 1 and less than or equal to n;
when | b m-1 -b m |≤b m-1 X 20%, and directly carrying out subsequent operations;
when | b 2m-1 -b 2m |＞b 2m-1 X 20%, and carrying out complete annealing treatment, wherein the complete annealing treatment comprises the following steps: the annealing temperature is 300-350 ℃, the heat preservation time is 2-3 h, the whole annealing process is carried out in a protective atmosphere, and the annealing is discharged after being cooled to below 50 ℃ along with the furnace;
the drawing speed of the fixed drawing in the sectional drawing is 10-40 m/min;
the drawing speed of the moving drawing in the sectional drawing is 10-20 m/min;
after the sectional type drawing is finished, the thickness of the pipe wall is b 2n The copper pipe with the thickness of b is drawn to the thickness of the pipe wall f When mm, the drawing speed is 4-6 m/min.
2. The method for manufacturing ultra-thin copper tube according to claim 1, wherein the copper tube is made of a material having a high thermal conductivity,
the pretreatment in the step 100) comprises cleaning, rolling and combined drawing;
the cleaning comprises polishing, descaling and degreasing;
the rolling is carried out by a three-roller planetary rolling mill;
and the combined drawing adopts a clamp to clamp for carrying out the triple drawing.
3. The method for manufacturing an ultra-thin wall copper tube as claimed in claim 1, wherein the copper tube is a copper tube,
and 200) the surfaces of the outer die and the core print are made of Ti (CN) metal ceramic materials.
4. A processing and manufacturing method for ultra-thin wall copper tube as claimed in claim 1 or 3,
step 200) carrying out mirror polishing on the surfaces of the outer die and the core print;
the friction coefficient between the outer die and the outer wall of the pre-copper pipe is controlled to be less than or equal to 0.10;
and the friction coefficient between the core print and the inner wall of the pre-copper pipe is controlled to be 0.02 to 0.04.
5. The method for manufacturing ultra-thin copper tube as claimed in claim 4, wherein the copper tube is made of copper,
the friction coefficient between the core print and the inner wall of the pre-copper pipe is 0.02-0.03.
6. The method for manufacturing ultra-thin copper tube according to claim 1, wherein the copper tube is made of a material having a high thermal conductivity,
step 200) the drawing process adopts finite element fitting control, and the finite element fitting control steps are as follows:
201 Drawing model establishment: firstly, selecting drawing conditions, and positioning deviation parameters of an external mold, a core print, the core print and the axis of a pre-copper pipe, analyzing and summarizing the existing mechanical model, setting a drawing range according to the mechanical model, and carrying out error comparison in the drawing range, thereby screening out an optimal drawing model under the condition of fixed drawing;
202 Analysis of deformation rule of pre-copper tube: based on the optimal drawing model screened in the step 201), establishing a finish Element Analysis model of the drawing deformation of the pre-copper pipe, performing deformation Analysis by using ANSYS according to the size change before and after drawing, and analyzing the drawing deformation change rule according to different working conditions to obtain a typical pre-copper pipe deformation change rule, namely a Finite Element Analysis result;
203 Verification of the Finite Element Analysis model built according to ANSYS: carrying out multiple groups of experiments on a copper sample, comparing the results with the Finite Element Analysis results obtained in the step 202), fitting the data, analyzing the results, and verifying the Finite Element Analysis model established in the step 202);
204 If the finished Element Analysis model in the step 203) is verified to be qualified through the detection of multiple groups of experimental data, the drawing processing step is carried out, and if the finished Element Analysis model is not qualified, the step is returned to the step 201).
7. The method for manufacturing ultra-thin copper tube as claimed in claim 6, wherein the copper tube is made of copper,
and step 201), the positioning deviation between the core print and the axle center of the pre-copper pipe is less than or equal to 0.01mm.
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