Horizontal continuous casting fine grain copper strip blank preparation process
By adding phosphorus to the copper liquid and controlling harmful elements, combined with multiple repeated rolling and annealing treatments, the problem of horizontal continuous cast copper tape cracking during stamping and bending at 90°C is solved, and the internal quality of the copper tape is significantly improved and surface properties.
Patent Information
- Application Number
- CN202411310271.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-19
- Publication Date
- 2024-12-27
AI Technical Summary
Horizontal continuous cast copper tape blanks are prone to cracking during stamping and bending at 90°C, which is mainly due to mass internal grains, microcracks and tissue defects.
By adding phosphorus to the copper liquid, the content of harmful elements is controlled, and the copper tape blank is continuously pulled and cast by horizontal continuous casting process, and repeated rolling and annealing are carried out multiple times, combining four-sided milling and degreasing to improve grain uniformity and surface quality.
It effectively improves the internal quality of the casting billet, ensures that the copper belt does not crack when it is 1.2mm thick, improves the performance of stamping and 90℃ bending, and improves the surface quality of the thick belt.
Smart Images
Figure CN119188172A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of copper strip production and processing, and particularly relates to a process for preparing a horizontal continuous casting fine-grain copper strip blank. Background Art
[0002] The thickness of horizontally continuously cast copper strip is generally around 1.2mm, which reaches the industry's product thickness limit when stamping and bending at 90°C. Addressing this issue primarily lies in the melting process. If the resulting ingot exhibits structural defects such as coarse grains, microcracks, shrinkage cavities, and porosity, these defects can lead to varying degrees of stamping cracking and 90°C bending cracking. Therefore, it is necessary to employ appropriate methods to overcome this problem. Summary of the Invention
[0003] The purpose of the present invention is to provide a horizontal continuous casting fine-grain copper strip preparation process so as to overcome the cracking problem during stamping and 90° bending when the horizontal continuous casting copper strip thickness is 1.2 mm, and to improve the grain uniformity and surface quality of the thick strip.
[0004] In order to achieve the above objectives, the technical solutions of the present invention are as follows.
[0005] A process for preparing a horizontal continuous casting fine-grain copper strip is characterized by comprising the following steps: Step S1: Billet melting: copper ingots are placed in a horizontal continuous casting furnace for melting, and phosphorus is added to the copper liquid; the content of harmful elements in the furnace is controlled to be below 10 PPM, such as sulfur and selenium; Step S2: Horizontal continuous casting: using a horizontal continuous casting furnace to continuously pull and cast copper strip billets; Step S3: Four-side milling: Use a milling machine to mill off the oxide scale on the upper and lower surfaces and sides of the copper strip blank; Step S4: rolling and homogenizing annealing: The copper strip blank obtained in step S3 is repeatedly rolled multiple times. The first rolling is repeated until a certain thickness of the copper strip blank is obtained, and the first annealing is performed. After the first annealing, the strip becomes soft. After annealing, there is residual ash on the surface, which is removed by cleaning to make the surface clean. Then, the copper strip is repeatedly rolled for a second time, and the second annealing is continued. After cleaning, the copper strip is rolled for a third time to obtain a finished product, which is then cleaned. Step S5: Degreasing and cleaning: The copper strip is subjected to alkaline cleaning, pickling, water cleaning and passivation treatment in a cleaning machine to remove grease from the surface of the copper strip and obtain an anti-oxidation layer through passivation treatment; Step S6: Finished product shearing: according to the order requirements, the copper strip is cut into the width size required by the customer, the product is cut by a shearing machine, and samples are sent for performance testing; Step S7: Packaging: After passing the inspection, the product packaging is stored in the warehouse.
[0006] Preferably, in step S1, the melting temperature of the copper ingot in the horizontal continuous casting furnace is 1165-1175°C.
[0007] Preferably, in step S1, the phosphorus content added to the copper liquid is: 10-20 PPM of phosphorus content in each piece of copper with a mass of 160 kg.
[0008] Preferably, in step S1, phosphorus is added to the copper liquid by using a phosphorus-copper alloy, which is wrapped with copper and pressed into the copper liquid, and the phosphorus content of the phosphorus-copper alloy block is 14% by mass.
[0009] Preferably, in step S2, the copper strip blank obtained has a thickness of 17.9 mm.
[0010] Preferably, in step S2, the slab drawing is performed in a double reverse push, small pitch, and fast pace manner, with a pitch of 4-5 mm and a drawing speed of 5-6 mm / s.
[0011] Preferably, in step S3, the upper and lower surfaces are milled by a milling cutter to remove the surface oxide layer by 0.7 mm, and the obtained copper strip has a thickness of 16.5 mm.
[0012] Preferably, in step S4, the first annealing temperature and time are: annealing at 390° C. for 5 hours.
[0013] Preferably, in step S4, the second annealing temperature and time are: annealing at 360° C. for 5 hours.
[0014] Preferably, in step S4, the thickness of the copper strip blank after the first repeated rolling is 2.3 mm; the thickness of the copper strip blank after the second repeated rolling is 1.35 mm; and the thickness of the finished product after the third repeated rolling is 1.2 mm.
[0015] The beneficial effects of this invention are that the process can effectively improve the internal quality of horizontal continuous casting ingots, improve the internal grain density of the ingots, and ensure that horizontal continuous casting copper strip ingots with a thickness of approximately 1.2 mm will not crack when stamped or bent at 90°C. This process ensures uniform mold cooling and reduces casting resistance by flattening the internal mold, regularly performing surface mold repairs and cooling tank cleaning. Phosphorus is added to increase copper fluidity, reduce the oxygen content in the copper liquid, increase the bonding between grains, and utilize a secondary annealing process to further improve grain uniformity and the surface quality of thick strips. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 Schematic diagram of the process steps used in the embodiment of the present invention.
[0017] Figure 2This is a physical photo of the slab fracture of the product obtained by the control group using the process.
[0018] Figure 3 This is a physical photo of a slab fracture obtained using the process in an embodiment of the present invention.
[0019] Figure 4 This is a physical photo of the surface of the product obtained by the control group using the process.
[0020] Figure 5 This is a photo of a real object on the surface obtained using a process in an embodiment of the present invention. DETAILED DESCRIPTION
[0021] The specific implementation of the present invention will be described below with reference to the accompanying drawings and examples for better understanding of the present invention. Example
[0022] like Figure 1 The present invention provides a horizontal continuous casting fine-grain copper strip preparation process, comprising the following steps: Step S1: Melting the billet: Place the copper ingot into a horizontal continuous casting furnace and melt it at a melting temperature of 1165-1175°C. Phosphorus is added to the molten copper, with the phosphorus content of each 160kg copper block being 10-20 parts per million (ppm). The content of harmful elements in the furnace, such as sulfur and selenium, is controlled to be below 10 ppm. The phosphorus-copper alloy is wrapped in copper and pressed into the molten copper, with the phosphorus content of the phosphorus-copper alloy block being 14% by mass. Step S2: Horizontal continuous casting, using a horizontal continuous casting furnace to continuously draw and cast copper strip billets, with a thickness of 17.9 mm; slab drawing uses double reverse thrust, small pitch, fast rhythm, pitch of 4-5 mm, and a drawing speed of 5-6 mm / s; Step S3: Four-side milling: Use a milling machine to mill off the oxide scale on the upper and lower surfaces and sides of the copper strip blank. Use a milling cutter to mill 0.7mm on each of the upper and lower surfaces to remove the surface oxide layer. The thickness of the copper strip is 16.5mm. Step S4: rolling and homogenizing annealing: The copper strip blank with a thickness of 16.5 mm is repeatedly rolled multiple times. The first rolling is repeated to a thickness of 2.3 mm, and the first annealing is performed at 390°C for 5 hours. After annealing, the strip becomes soft. After annealing, there is residual ash on the surface, which is removed by cleaning to make the surface clean. After a second rolling, the thickness reaches 1.35 mm, and a second annealing is continued at 360°C for 5 hours. After cleaning, a third rolling is performed to obtain a finished product with a thickness of 1.2 mm, which is then cleaned. Step S5: Degreasing and cleaning: the copper strip is subjected to alkaline cleaning, acid cleaning, water cleaning and passivation treatment in a cleaning machine to remove grease from the surface of the copper strip and obtain an anti-oxidation layer through passivation treatment; Step S6: Finished product shearing: according to the order requirements, the copper strip is cut into the width size required by the customer, the product is cut by a shearing machine, and samples are sent for performance testing; Step S7: Packaging: After passing the inspection, the product packaging is stored in the warehouse.
[0023] The preparation process of the horizontal continuous casting fine-grained copper strip in this control group includes the following steps: Step S1: melting the billet, adding the copper ingot into the horizontal continuous casting furnace for melting at a melting temperature of 1165-1175°C, and adding phosphorus to the copper liquid; Step S2: Horizontal continuous casting: using a horizontal continuous casting furnace to continuously draw and cast copper strip billets with a thickness of 17.9 mm; slab drawing is performed using a single reverse push; Step S3: four-side milling, using a milling machine to mill off the oxide scale on the upper and lower surfaces and sides of the copper strip blank; Step S4: rolling and homogenizing annealing treatment: the copper strip blank is repeatedly rolled multiple times and annealed once; Step S5: Degreasing and cleaning: the copper strip is subjected to alkaline cleaning, acid cleaning, water cleaning and passivation treatment in a cleaning machine to remove grease from the surface of the copper strip and obtain an anti-oxidation layer through passivation treatment; Step S6: Finished product shearing: according to the order requirements, the copper strip is cut into the width size required by the customer, the product is cut by a shearing machine, and samples are sent for performance testing; Step S7: Packaging: After passing the inspection, the product packaging is stored in the warehouse.
[0024] Tests were conducted on a control group and an example product. Both the control group and the example product had a thickness of 1.2 mm and a width of 53 mm, with a thickness tolerance of -0.03 mm and a width tolerance of -0.05 mm and -0.15 mm, respectively. Tables 1 and 2 show the test data for the control group and the example product, respectively.
[0025] Table 1. Performance test data of control group products
[0026] From the above data, it can be seen that the product has low elongation and small deep drawing value, which cannot meet the bending requirements.
[0027] Table 2. Performance test data of the product in the embodiment
[0028] From the above data, it can be seen that the elongation of the product is greatly improved, the deep drawing value is significantly improved, and the bending requirements are met.
[0029] like Figure 2 The following is a photo of the slab fracture surface of the product obtained by the control group using the process. Figure 3The following are photos of the slab fractures of the product obtained by the process in the embodiment of the present invention. It can be seen that the first slab fracture is loose, while the second one is tight. The product performance is significantly improved by the process of this embodiment.
[0030] like Figure 4 Shown is a surface photo of the product obtained by the control group using the process. Figure 5 As shown in FIG, a surface photo of a product obtained by using the process in the embodiment of the present invention is shown. It can be seen that the grains obtained by using the control group process are coarser, while the grains of the product obtained by using the process in the embodiment of the present invention are finer.
[0031] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.
Claims
1. A process for preparing a horizontal continuous casting fine-grained copper strip, characterized in that: The following steps are involved: Step S1: melting the billet: adding the copper ingot into the horizontal continuous casting furnace for melting, and adding phosphorus into the copper liquid; Control the content of harmful elements in the furnace to below 10 PPM, including sulfur and selenium; Step S2: horizontal continuous casting: using a horizontal continuous casting furnace to continuously pull and cast the copper strip billet; Step S3: four-side milling: using a milling machine to mill off the oxide scale on the upper and lower surfaces and sides of the copper strip blank; Step S4: rolling and homogenization annealing treatment: the copper strip blank obtained in step S3 is repeatedly rolled for many times, the first repeated rolling is performed until a copper strip blank of a certain thickness is obtained, and the first annealing is performed, after the first annealing, the strip becomes soft, and there is residual ash on the surface after annealing, which is removed by cleaning to make the surface clean; then the second repeated rolling is performed, the second annealing is continued, and after cleaning, the third rolling is performed to obtain a finished product, and cleaning is performed; Step S5: degreasing and cleaning: the copper strip is subjected to alkaline cleaning, acid cleaning, water cleaning and passivation treatment in a cleaning machine to remove grease from the surface of the copper strip, and an anti-oxidation layer is obtained through passivation treatment; Step S6: Finished product shearing: according to the order requirements, the copper strip is cut into the width size required by the customer, the product is cut by a shearing machine, and samples are sent for performance testing; Step S7: Packaging: After passing the inspection, the product packaging is stored in the warehouse.
2. A process for preparing a horizontal continuous casting fine-grained copper strip according to claim 1, characterized in that: In the step S1, the melting temperature of the copper ingot in the horizontal continuous casting furnace is 1165-1175°C.
3. A process for preparing a horizontal continuous casting fine-grained copper strip according to claim 1, characterized in that: In the step S1, the phosphorus content added to the copper liquid is: 10-20 PPM of phosphorus in each piece of copper with a mass of 160 kg.
4. A process for preparing a horizontal continuous casting fine-grained copper strip according to claim 1, characterized in that: In the step S1, phosphorus is added to the copper liquid by using a phosphor-copper alloy, which is wrapped with a copper sheet and pressed into the copper liquid, and the phosphorus mass content in the phosphor-copper alloy block is 14%.
5. A process for preparing a horizontal continuous casting fine-grained copper strip according to claim 1, characterized in that: In step S2, the copper strip blank obtained has a thickness of 17.9 mm.
6. A process for preparing a horizontal continuous casting fine-grained copper strip according to claim 1, characterized in that: In step S2, the slab casting is performed by double reverse thrust, small pitch and fast rhythm, with a pitch of 4-5 mm and a pulling speed of 5-6 mm / s.
7. A process for preparing a horizontal continuous casting fine-grained copper strip according to claim 1, characterized in that: In step S3, the upper and lower surfaces are milled by a milling cutter to remove the surface oxide layer by 0.7 mm, and the thickness of the obtained copper strip is 16.5 mm.
8. A process for preparing a horizontal continuous casting fine-grained copper strip according to claim 1, characterized in that: In step S4, the first annealing temperature and time are: annealing at 390° C. for 5 hours.
9. A process for preparing a horizontal continuous casting fine-grained copper strip according to claim 1, characterized in that: In step S4, the second annealing temperature and time are: annealing at 360° C. for 5 hours.
10. A process for preparing a horizontal continuous casting fine-grained copper strip according to claim 1, characterized in that: In the step S4, the thickness of the copper strip blank after the first repeated rolling is 2.3 mm; the thickness of the copper strip blank after the second repeated rolling is 1.35 mm; and the finished product with a thickness of 1.2 mm is obtained by the third repeated rolling.