A short-process production process of large-diameter red copper pipe

Abstract

The application discloses a short-process production process for large-diameter red copper pipes and belongs to the technical field of red copper pipe production, and comprises the following steps: step 1, furnace washing and temperature reduction; step 2, horizontal continuous casting; step 3, cold rolling; step 4, roller bottom annealing; step 5, drawing; step 6, roller bottom annealing; and step 7, packaging. The production process disclosed by the application is short in process, low in energy consumption and die consumption and high in material yield, meanwhile, the production process guarantees product quality, avoids large wall thickness deviation, casting cracks and coarse grain structure.

Description

Technical Field

[0001] This invention relates to the field of copper tube production technology, and in particular to a short-process production technology for large-diameter copper tubes. Background Technology

[0002] With the increase in electricity consumption in cities and industries, substations are also getting bigger, leading to increased current. The existing solid busbars cannot meet the requirements of high current power supply, so shielded insulated copper busbars with better performance are needed. The large-scale construction of new energy power generation projects such as wind power and photovoltaics also requires the construction of supporting substations, which also require a large number of shielded insulated copper busbars.

[0003] However, the copper tubes used to manufacture busbars have a large diameter and cannot be produced by casting and rolling. Instead, they are produced by the traditional extrusion method. The traditional extrusion method has disadvantages such as a long process flow, high energy consumption for secondary heating, large mold consumption, and low yield. Furthermore, due to the characteristics of large diameter and thin wall thickness of the cast tube blank, it is not conducive to horizontal continuous casting, which can easily lead to large wall thickness deviation, casting cracks, and coarse grain structure. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the technical problem to be solved by the present invention is to propose a production process that is short in process, low in energy consumption, high in yield, low in mold consumption, while ensuring product quality and avoiding large wall thickness deviation, casting cracks, and coarse grain structure.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] This invention provides a short-process manufacturing technology for large-diameter copper tubes, comprising the following steps:

[0007] Step 1: Furnace cleaning and scale reduction. Electrolytic copper plates are continuously added to the molten copper in the melting furnace, while the billet is stretched to dilute the molten copper and reduce the phosphorus content in the molten copper. The molten copper enters the holding furnace through the submerged channel.

[0008] Step 2: Horizontal continuous casting. Cooling water is introduced into the channel in the middle of the inner core, while the molten copper flows through the copper molten gate into the annular cavity formed by the graphite mold and the inner core. A copper sleeve is provided on the outer wall of the graphite mold. The graphite mold and the copper sleeve adopt a non-uniform interference fit to form a gradually changing thermal conductivity coefficient. Under the primary water cooling effect of the cooling water and the copper sleeve, the molten copper is cooled in the annular cavity to form a copper tube. The copper tube is moved to the secondary water cooling zone for secondary water cooling by a traction mechanism.

[0009] Step 3: Cold rolling, using the upper and lower rolls of a cold rolling mill to cold roll the copper tube;

[0010] Step 4: Roller hearth annealing, using a roller hearth annealing furnace for heat treatment;

[0011] Step 5: Pulling. The copper tube is installed in the pulling machine, and the copper tube is stretched axially using the pulling machine.

[0012] Step 6: Roller hearth annealing, the drawn copper tube is heat-treated again in a roller hearth annealing furnace;

[0013] Step 7: Packaging. Pack the copper tubes according to the requirements and put them into storage.

[0014] A preferred embodiment of the present invention is that, in step 2, when the temperature of the molten copper drops to 1160±5°, it enters the annular cavity formed by the graphite mold and the inner core through the molten copper gate.

[0015] A preferred embodiment of the present invention is that an electromagnetic generating cavity is provided on the outer wall of the graphite mold, and a plurality of electromagnetic coils are installed in the electromagnetic generating cavity. The electromagnetic coils are connected to a power source, and the electromagnetic generating cavity is located on one side of the copper sleeve and close to the copper liquid gate.

[0016] The preferred technical solution of the present invention is that the temperature difference of the cooling water outlet in the primary water cooling is controlled at ≤15℃, and the secondary cooling adopts spray cooling directly on the copper tube by spray pipe.

[0017] A preferred embodiment of the present invention is that the annealing temperature in step 4 is 350°C and the annealing time is 100 min.

[0018] A preferred embodiment of the present invention is that nitrogen gas is introduced into the annealing furnace during the copper tube annealing process to protect the copper tube.

[0019] A preferred embodiment of the present invention is that the hardness range of the annealed copper tube in step 6 is 55-65 HV.

[0020] The preferred technical solution of the present invention is that the copper liquid casting temperature is 1250℃, the cooling water flow rate of the primary water cooling is 1200L / h, the spray cooling water flow rate of the secondary water cooling is 800L / h, and the traction speed is 100mm / min.

[0021] The beneficial effects of this invention are as follows: Detailed Implementation

[0022] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0023] A short-process manufacturing process for large-diameter copper tubes includes the following steps:

[0024] Step 1: Furnace cleaning and de-liming. Electrolytic copper plates are continuously added to the molten copper in the melting furnace, while the billet is stretched to dilute the molten copper and reduce the phosphorus content. The molten copper enters the holding furnace through the submerged channel. The purpose is to convert the process of producing TP2 copper tubes into the process of producing TU2 copper tubes.

[0025] Step 2: Horizontal continuous casting. Cooling water is introduced into the channel in the middle of the inner core, while molten copper flows through the copper molten gate into the annular cavity formed by the graphite mold and the inner core. A copper sleeve is provided on the outer wall of the graphite mold. The graphite mold and the copper sleeve adopt a non-uniform interference fit to form a gradually changing thermal conductivity coefficient. Under the primary water cooling effect of the cooling water and the copper sleeve, the molten copper is cooled in the annular cavity to form a copper tube. The copper tube is moved to the secondary water cooling zone for secondary water cooling by a traction mechanism. An electromagnetic generation cavity is provided on the outer wall of the graphite mold. Several sets of electromagnetic coils are installed in the electromagnetic generation cavity. The electromagnetic coils are connected to a power source. The electromagnetic generation cavity is located on one side of the copper sleeve and close to the copper molten gate.

[0026] Step 3: Cold rolling, using the upper and lower rolls of a cold rolling mill to cold roll the copper tube;

[0027] Step 4: Roller hearth annealing, using a roller hearth annealing furnace for heat treatment;

[0028] Step 5: Pulling. The copper tube is installed in the pulling machine, and the copper tube is stretched axially using the pulling machine.

[0029] Step 6: Roller hearth annealing. The drawn copper tube is heat-treated again in a roller hearth annealing furnace. The hardness range of the annealed copper tube is 55-65HV.

[0030] Step 7: Packaging. Pack the copper tubes according to the requirements and put them into storage.

[0031] The copper tube graphite mold, in conjunction with the copper sleeve, effectively reduces the cooling capacity of the lower part of the copper tube under primary and secondary water cooling, ensuring consistent cooling uniformity between the upper and lower parts. This prevents uneven cooling from causing large deviations in the copper tube wall thickness or even cracks, resulting in a fine and uniform as-cast structure, thus improving the quality and yield of the copper tube. Electromagnetic stirring causes the molten copper to rotate unidirectionally within the crystallization zone, refining the grains and resulting in a finer solidified structure, ensuring a smooth copper tube surface. Direct cold rolling of the tube blank simplifies the process, effectively improving material utilization while maintaining high precision and surface roughness. It also offers advantages such as streamlined process, low energy consumption, high yield, and low mold consumption.

[0032] As a possible implementation of this solution, preferably, in step 2, when the temperature of the molten copper drops to 1160±5°, it enters the annular cavity formed by the graphite mold and the inner core through the molten copper gate, so as to reduce the temperature difference during the crystallization process and ensure the quality of the copper tube cooling.

[0033] As one possible implementation of this solution, preferably, the temperature difference of the cooling water outlet in the primary water cooling is controlled to be ≤15℃, and the secondary cooling adopts spray cooling directly onto the copper tube through a spray nozzle to ensure uniform cooling of the copper tube surface and reduce the subsequent stretching speed.

[0034] As a possible implementation of this solution, preferably, the annealing temperature in step 4 is 350°C and the annealing time is 100 min. Nitrogen gas is introduced into the annealing furnace during the copper tube annealing process to protect the copper tube. The purpose of using a roller hearth annealing furnace for heat treatment is to eliminate residual stress and work hardening, while obtaining a copper tube with fine, uniform grains and a dense structure.

[0035] As one possible implementation of this solution, preferably, the copper liquid casting temperature is 1250°C, the cooling water flow rate for primary water cooling is 1200L / h, the spray cooling water flow rate for secondary water cooling is 800L / h, and the traction speed is 100mm / min, to ensure the cooling efficiency of the copper tube and improve the quality of the copper tube.

[0036] This invention has been described through preferred embodiments. Those skilled in the art will understand that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. This invention is not limited to the specific embodiments disclosed herein; other embodiments falling within the scope of the claims are also within the protection scope of this invention.

Claims

1. A short-process production technology for large-diameter copper pipes, characterized in that: Includes the following steps: Step 1: Furnace cleaning and scale reduction. Electrolytic copper plates are continuously added to the molten copper in the melting furnace, while the billet is stretched to dilute the molten copper and reduce the phosphorus content in the molten copper. The molten copper enters the holding furnace through the submerged channel. Step 2: Horizontal continuous casting. Cooling water is introduced into the channel in the middle of the inner core, while the molten copper flows through the copper molten gate into the annular cavity formed by the graphite mold and the inner core. A copper sleeve is provided on the outer wall of the graphite mold. The graphite mold and the copper sleeve adopt a non-uniform interference fit to form a gradually changing thermal conductivity coefficient. Under the primary water cooling effect of the cooling water and the copper sleeve, the molten copper is cooled in the annular cavity to form a copper tube. The copper tube is moved to the secondary water cooling zone for secondary water cooling by a traction mechanism. Step 3: Cold rolling, using the upper and lower rolls of a cold rolling mill to cold roll the copper tube; Step 4: Roller hearth annealing, using a roller hearth annealing furnace for heat treatment; Step 5: Pulling. The copper tube is installed in the pulling machine, and the copper tube is stretched axially using the pulling machine. Step 6: Roller hearth annealing, the drawn copper tube is heat-treated again in a roller hearth annealing furnace; Step 7: Packaging. Pack the copper tubes according to the requirements and put them into storage. In step 4, the annealing temperature is 350°C and the annealing time is 100 min. Nitrogen gas is introduced into the annealing furnace during the copper tube annealing process to protect the copper tube; The hardness range of the annealed copper tube in step 6 is 55-65 HV.

2. The short-process production process for large-diameter copper tubes according to claim 1, characterized in that: In step 2, when the temperature of the molten copper drops to 1160±5°, it enters the annular cavity formed by the graphite mold and the inner core through the molten copper gate.

3. The short-process production process for large-diameter copper tubes according to claim 1, characterized in that: The graphite mold has an electromagnetic generating cavity on its outer wall. Several sets of electromagnetic coils are installed in the electromagnetic generating cavity. The electromagnetic coils are connected to a power source. The electromagnetic generating cavity is located on the side of the copper sleeve and is close to the copper liquid gate.

4. The short-process production process for large-diameter copper tubes according to claim 1, characterized in that: The temperature difference of the cooling water outlet in the primary water cooling is controlled at ≤15°C, and the secondary water cooling uses a spray nozzle to directly spray and cool the copper tube.

5. The short-process production process for large-diameter copper tubes according to claim 1, characterized in that: The primary water cooling flow rate is 1200L / h, the secondary water cooling spray flow rate is 800L / h, and the traction speed is 100mm / min.