Production process of copper-iron alloy slabs by non-vacuum down-drawing continuous casting

Abstract

This invention provides a process for producing copper-iron alloy slabs by non-vacuum down-draw continuous casting. [Solution] The process for producing copper-iron alloy slabs using non-vacuum down-drawing continuous casting mainly includes raw material preparation, furnace loading, smelting, refining and degassing, pouring, casting, and ingot cooling. Electrolytic copper sheet and CuFe50 master alloy are used as smelting raw materials, and copper-iron alloy slabs are produced through a non-vacuum down-drawing continuous casting process. Compared to conventional vacuum smelting processes, the requirements for equipment are lower, and appropriate measures such as inert gas shielding and iron content adjustment are taken during the casting process to effectively control the alloy elements and oxygen content. This has the advantages of a stable process, simple operation, and low smelting production costs, making it possible to realize the industrial production of copper-iron alloy slabs.

Description

[Technical field]

[0001] The present invention relates to the technical field of metal smelting, in particular to the production process of copper-iron alloy slabs by non-vacuum down-drawing continuous casting. [Background technology]

[0002] As high-strength, high-conductivity copper-iron alloys are widely used in various industries, the requirements for the use performance and manufacturing cost of such high-strength, high-conductivity copper-iron alloys are becoming higher. Copper-iron alloys have the properties of copper, such as electrical conductivity, thermal conductivity, ductility, elasticity, and the like, and the properties of iron, such as wear resistance, strength, hardness, and magnetism, and therefore exhibit unique and excellent properties, such as electromagnetic shielding, elasticity, electrical conductivity, heat dissipation, wear resistance, and antibacterial properties, and more. Moreover, copper-iron alloys can be processed into various physical forms, such as rods, cables, plates, films, powders, and tubes, and can be applied in various industrial fields, and have excellent competitiveness and broad market prospects.

[0003] However, according to the copper-iron phase diagram, the two are almost insoluble in each other at room temperature, the solubility remains zero at 300℃, and the solubility is only about 5% at 1094℃. Due to the extremely low solubility of Fe in Cu, the alloy is very likely to form a structure with serious segregation during solidification, which has a serious impact on the application of CuFe alloys. On the other hand, rapid solidification can refine the crystal grains and increase the solid solubility, and is also an effective method to suppress or reduce the formation of segregation structures during the solidification of CuFe alloys, so research on rapid solidification behavior has attracted more and more attention.

[0004] At present, there are several methods for producing CuFe alloys both at home and abroad, as follows: Vacuum arc smelting: A certain ratio of copper and iron ingots is melted in a vacuum induction furnace, and poured into a mold when it is completely melted. Usually, induction smelting is combined with strain aging to improve the performance of copper-iron alloys, but such ordinary induction smelting is prone to segregation. Strain in-situ composite: The original structure of CuFe in-situ composite is generally a homogeneous distribution of dendritic (smelting) or granular (powder metallurgy) Fe phase in the Cu matrix, and after a large amount of strain, the Fe phase becomes fibrous. In order to better improve the overall performance of CuFe alloys, the strain aging method is often used, and several heat treatments are added during the straining process, but it is still in the research stage at present. Mechanical alloying method: A certain ratio of Cu powder and Fe powder is polished for a long time in a high-energy ball mill, and the metal powder is subjected to frequent collisions to refine the structure, eventually reaching an atomic level of mixing to achieve the purpose of alloying. However, this method is prone to impurity elements being mixed in the ball mill, and is expensive.

[0005] In view of the above, there remains a need in the current market for a low-cost, easy-to-operate fabrication process for industrially producing high-quality copper-iron alloy slabs. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to overcome the above-mentioned shortcomings of the prior art and to provide a production process for copper-iron alloy slabs by non-vacuum down-drawing continuous casting, which has advantages such as a stable process, simple operation, and low production cost, and can realize industrial production of copper-iron alloy slabs. [Means for solving the problem]

[0007] In order to achieve the above objectives, the present invention provides the following technical solutions:

[0008] The process for producing a copper-iron alloy slab by non-vacuum down-drawing continuous casting according to the present invention includes the following steps S1 to S7: S1 is a raw material preparation step of preparing an electrolytic copper plate having a mass percentage of 80% to 95% and an Fe element having a mass percentage of 5% to 20% according to the composition ratio of a copper-iron alloy, the Fe element being prepared in the form of a CuFe50 master alloy; S2 is a step of filling the furnace with raw materials, which is a step of filling the furnace with the flux, CuFe50 mother alloy, electrolytic copper plate, and coating material in sequence; S3 is a step of heating the smelting furnace to 1420-1450°C to melt the copper-iron master alloy, in which the copper-iron master alloy is melted by increasing the temperature, and gas shielding is performed at the furnace throat during the melting by increasing the temperature; S4 is a refining and degassing step in which degassing is performed by passing argon gas through the mixture and deoxidizing using an oxygen scavenger; S5 is the pouring step, when the temperature reaches 1300-1450℃, pouring starts. If the pouring temperature is too high, the internal gradient of the ingot will be large, the thermal stress will increase, the tendency to crack will increase, and the wall of the sump will become thin, making it easy to crack on the large surface. On the other hand, if the temperature is too low, the viscosity of the molten metal will increase, the fluidity will decrease, and defects such as cold shut and slag entrapment will easily occur; S6 is a square molten metal template When the flow rate reaches 70-85%, the electromagnetic stirring is turned on, and its specific parameters are frequency 3-10Hz, current 80-100A, the casting speed is slowly adjusted from low to high to 60-80mm / min, and the mechanical vibration is 30 times / min. This is the casting step. The casting speed is the key parameter during casting that determines the sump depth. For flat ingots, if the casting speed is too high, the wall of the sump on the wide surface will become thin, and the tensile stress on the surface layer of the wide surface, which was originally in a tensile stress state, will increase, which will easily lead to cracks. On the other hand, if the casting speed is too low, it may lead to side cracks or defects such as cold shuts on the narrow surface; The S7 is template In the ingot cooling step, water is sprayed at a certain angle onto the ingot that has been pulled out after solidification to perform secondary cooling. template The advantage of water cooling by water quenching is that it can realize "hot top casting" inside, slow down the solidification speed of the molten metal at the top end, ensure timely feeding, and is favorable for the floating removal of slag and gas.

[0009] Preferably, the CuFe50 master alloy is smelted by the following first to third steps: The first step is to prepare the raw materials and load them into the furnace. The Cu and Fe raw materials are weighed out in a 1:1 ratio, mixed uniformly, and then loaded into a crucible and placed in a vacuum smelting furnace. The second step is vacuum induction smelting. Turn on the mechanical pump and low vacuum flapper valve to suck the vacuum. When the pressure in the vacuum smelting furnace is P≦0.08MPa, turn on the Roots pump. When the vacuum is sucked until the vacuum level is P≦4Pa, increase the power of the heating device to 20KW~30KW and keep warm for 5min~10min. Increase the heating power of the heating device to 40KW~50KW and keep warm for 5min~10min. Increase the heating power of the heating device to 60KW~70KW. After the raw materials in the crucible are uniform up and down, reduce the heating power to 20KW. Slowly fill the furnace body with argon gas. When the pressure in the furnace rises to 0.08Mpa, stop filling the argon gas, increase the power to 70KW±5KW, and smelt for 1min~2min. The third step is pouring and unloading. The power of the vacuum smelting furnace is reduced to 40KW±5KW and maintained for 0.5 minutes, pouring into the mold is started, and once pouring is completed, the heating is turned off and the material is cooled for 60 minutes before being unloaded from the furnace. The CuFe alloy produced by this method has a dense structure, few pores and inclusions, and is free of defects such as macro-segregation and micro-segregation, ensuring the quality of the final copper-iron slab.

[0010] Preferably, the coating agent is quartz glass and the amount used is 0.25 to 0.50% by weight of the alloy, and the solvent is a mixture of sodium silicate and fluorite and the amount used is 0.32 to 0.45% by weight of the alloy.

[0011] Preferably, in S3, the Fe content is sampled and detected using a crucible during smelting, and an appropriate amount of CuFe master alloy is added accordingly to adjust the molten metal composition until the iron (Fe) content reaches a target value.

[0012] Preferably, in S4, the specific procedure of deoxidizing with a deoxidizer is deoxidizing with an aluminum wire, deoxidizing with a CuMg alloy, and adding a titanium wire before being removed from the furnace.

[0013] Preferably, in S6, when the amount of molten metal in the crucible of the smelting furnace decreases to less than 10% of the original amount, the pulling speed is slowly decreased until it stops, and when the ingot is completely solidified, the cooling water is turned off.

[0014] Preferably, in S7, the flow rate of the cooling water is set to 6.0 to 8.0 before the casting. m 3 / h If the water flow rate is too high, the cooling rate will be too high, causing stress concentrations and cold shuts, which can lead to cracking, while if the water flow rate is too low, the ingot will cool too slowly, which can lead to coarsening of the structure, poor performance, and other defects.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention uses a manufacturing process suitable for copper-iron alloy slabs, and in particular, through a large amount of process exploration, a series of key parameters for non-vacuum smelting casting for different specifications are determined. (2) The present invention is a built-in template The copper-iron solution is electromagnetically stirred using a magnetron to increase the equiaxed crystal ratio, refine the grains, reduce surface and subsurface pores and inclusions, and improve center porosity and segregation of the ingot. (3) The copper-iron alloy slab produced by the present invention can be used as a rolling material for copper-iron alloy ribbons, which reduces material loss and production costs compared to conventional round ingots. (4) The present invention uses a non-vacuum down-drawing continuous casting process, which places less demands on equipment than the conventional vacuum melting process. During casting, appropriate measures such as inert gas shielding and adjustment of the iron content are taken to effectively control the alloy components and oxygen content, making the operation simple and stable and reliable. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a flow chart of a process according to the present invention. [Diagram 2] FIG. 2 is a diagram showing the actual embodiment of the present invention. [Diagram 3] FIG. 3 is a metal structure diagram of Example 1 of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, the technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings in the embodiments of the present invention. Of course, the described embodiments are only some of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without paying creative labor are all within the protection scope of the present invention.

[0018] (Examples 1 to 3) (1) CuFe50 master alloy smelting steps: First step: preparing raw materials and loading into the furnace. Cu and Fe raw materials are weighed out in a 1:1 content percentage ratio, mixed uniformly, and then loaded into a crucible and placed into a vacuum smelting furnace. The second step is vacuum induction smelting. Turn on the mechanical pump and low vacuum flapper valve to suck the vacuum. When the pressure inside the vacuum smelting furnace is P≦0.08MPa, turn on the roots pump. When the vacuum is sucked until the vacuum degree is P≦4Pa, increase the power of the heating device to 20KW and keep warm for 5min. Increase the heating power of the heating device to 40KW and keep warm for 5min. Increase the heating power of the heating device to 60KW. After the raw materials in the crucible are uniform up and down, reduce the heating power to 20KW. Slowly fill the vacuum smelting furnace with argon gas. When the pressure inside the furnace rises to 0.08Mpa, stop filling the argon gas, increase the power to 65KW, and smelt for 1min. The third step is pouring and unloading. The power of the vacuum smelting furnace is reduced to 35KW and maintained for 0.5min, pouring into the mold is started, and once pouring is completed, the heating is turned off and the material is cooled for 60min before being unloaded.

[0019] (2) Casting steps of copper-iron alloy slabs: S1: A step of preparing an electrolytic copper plate and Fe element in mass percent according to the composition ratio of a copper-iron alloy, in which the Fe element is prepared in the form of a CuFe50 master alloy. S2: A step of packing raw materials into a furnace, in which a flux, a CuFe50 mother alloy, an electrolytic copper plate, and a coating agent are sequentially packed into the furnace, the coating agent being quartz glass, and the flux being a mixture of sodium silicate and fluorite. S3: The temperature of the smelting furnace is heated to 1420°C to melt the copper-iron master alloy. The melting is performed by increasing the temperature and gas shielding is performed at the furnace mouth during the melting. During the melting, the Fe content is sampled and detected using a crucible, and an appropriate amount of CuFe50 master alloy is added accordingly to adjust the molten metal composition until the iron content reaches the target value. S4: This is a refining and degassing step in which argon gas is passed through to perform deoxidation, followed by deoxidation with aluminum wire, deoxidation with CuMg alloy, and addition of titanium wire before removal from the furnace. S5: When the temperature reaches 1300℃, the casting step starts. If the casting temperature is too high, the internal gradient of the ingot will be large, the thermal stress will increase, and the tendency to crack will increase. Also, the wall of the sump will become thin, and it will be easy to crack on the large surface. On the other hand, if the temperature is too low, the viscosity of the molten metal will increase, the fluidity will decrease, and defects such as cold shut and slag entrapment will easily occur. S6: The molten metal is square templateWhen the flow reaches 70%, the electromagnetic stirring is turned on, and the specific parameters are frequency 310Hz, current 80A, the casting speed is adjusted from low to high slowly to 60mm / min, and the mechanical vibration is 30 times / min. The casting speed is the key parameter during casting that determines the sump depth. For flat ingots, if the casting speed is too high, the wall of the sump on the wide surface will become thin, and the tensile stress on the surface of the wide surface, which was originally in a tensile stress state, will increase, making it easier to crack. On the other hand, if the casting speed is too low, it may cause side cracks or defects such as cold shuts on the narrow surface. S7: template In the ingot cooling step, water is sprayed at a certain angle onto the ingot that has been pulled out after solidification to perform secondary cooling. template The advantage of water cooling by this method is that it can realize "hot top casting" inside, reduce the solidification speed of the molten metal at the top end, ensure timely feeding, and is favorable for the floating removal of slag and gas. m 3 / h If the water flow rate is too high, the cooling rate will be too high, causing stress concentration and cold shut formation, which will lead to cracks, while if the water flow rate is too low, the cooling rate of the ingot will be too slow, which will lead to coarsening of the structure, poor performance, and other defects. When the amount of molten metal in the crucible of the smelting furnace falls to less than 10% of the original amount, the pulling speed will be stopped. Slowly lower it and when the ingot has completely solidified, turn off the cooling water.

[0020] A total of three sets of examples were prepared according to the differences in the initial raw materials, and the detailed raw material compositions and casting parameters are as shown in Table 1. The actual copper-iron slab prepared in Example 1 is as shown in Figure 2, and its metal structure diagram is as shown in Figure 3, which proves that the prepared copper-iron slab has a uniform structure and little segregation. Table 1. Raw materials and performance table for Examples 1 to 3 [Table 1]

[0021] (Examples 4 to 6) (1) CuFe50 master alloy smelting steps: First step: preparing raw materials and loading into the furnace. Cu and Fe raw materials are weighed out in a 1:1 content percentage ratio, mixed uniformly, and then loaded into a crucible and placed into a vacuum smelting furnace. The second step is vacuum induction smelting. Turn on the mechanical pump and low vacuum flapper valve to suck the vacuum. When the pressure inside the vacuum smelting furnace reaches P≦0.08MPa, turn on the roots pump. When the vacuum is sucked until the vacuum level reaches P≦4Pa, increase the power of the heating device to 30KW and keep warm for 10min. Increase the heating power of the heating device to 50KW and keep warm for 10min. Increase the heating power of the heating device to 70KW. After the raw materials in the crucible are uniform up and down, reduce the heating power to 20KW. Slowly fill the vacuum smelting furnace with argon gas. When the pressure inside the furnace rises to 0.08Mpa, stop filling the argon gas, increase the power to 75KW, and smelt for 2min. The third step is pouring and unloading. The power of the vacuum smelting furnace is reduced to 45KW and maintained for 0.5min, pouring into the mold is started, and once pouring is completed, the heating is turned off and the material is cooled for 60min before being unloaded.

[0022] (2) Smelting process of copper-iron alloy slab: S1: A step of preparing an electrolytic copper plate and Fe element in mass percent according to the composition ratio of a copper-iron alloy, in which the Fe element is prepared in the form of a CuFe50 master alloy. S2: A step of packing raw materials into a furnace, in which a flux, a CuFe50 mother alloy, an electrolytic copper plate, and a coating agent are sequentially packed into the furnace, the coating agent being quartz glass, and the flux being a mixture of sodium silicate and fluorite. S3: The temperature of the smelting furnace is heated to 1450°C to melt the copper-iron master alloy. The copper-iron master alloy is melted by increasing the temperature. During the melting process, gas shielding is performed at the furnace throat. During the melting process, the Fe content is sampled and detected using a crucible. An appropriate amount of CuFe50 master alloy is added according to the sample, and the molten metal components are adjusted until the iron content reaches the target value. Adjust. S4: This is a refining and degassing step in which argon gas is passed through to perform deoxidation, followed by deoxidation with aluminum wire, deoxidation with CuMg alloy, and addition of titanium wire before removal from the furnace. S5: When the temperature reaches 1450℃, the casting step starts. If the casting temperature is too high, the internal gradient of the ingot will be large, the thermal stress will increase, and the tendency to crack will increase. The wall of the sump will become thin, and it will be easy to crack on the large surface. On the other hand, if the temperature is too low, the viscosity of the molten metal will increase, the fluidity will decrease, and defects such as cold shut and slag entrapment will easily occur. S6: The molten metal is square template When the flow reaches 85%, the electromagnetic stirring is turned on, and its specific parameters are frequency 10Hz, current 100A, the casting speed is adjusted from low to high slowly to 80mm / min, and the mechanical vibration is set to 30 times / min. The casting speed is a key parameter during casting that determines the sump depth. For flat ingots, if the casting speed is too high, the wall of the sump on the wide surface will become thin, and the tensile stress on the surface of the wide surface, which was originally in a tensile stress state, will increase, making it easier to crack. On the other hand, if the casting speed is too low, it may cause side cracks or defects such as cold shuts on the narrow surface. S7: template In the ingot cooling step, water is sprayed at a certain angle onto the ingot that has been pulled out after solidification to perform secondary cooling. template The advantage of water cooling by this method is that it can realize "hot top casting" inside, reduce the solidification speed of the molten metal at the top end, ensure timely feeding, and is favorable for the floating removal of slag and gas. m 3 / hIf the water flow rate is too high, the cooling rate will be too high, causing stress concentration and cold shut formation, which can lead to cracking, while if the water flow rate is too low, the ingot will cool too slowly, which can lead to coarsening of the structure, poor performance, and other defects. When the amount of molten metal in the smelting furnace crucible falls to less than 10% of its original amount, the pulling speed is slowly reduced to a halt, and when the ingot has completely solidified, the cooling water is turned off.

[0023] A total of three examples were prepared according to the difference in the initial raw materials, and the detailed raw material composition and casting parameters are as shown in Table 2. Table 2: Raw materials and performance table for Examples 4 to 6 [Table 2]

[0024] Finally, it should be noted that the above examples are merely for illustrating the technical solutions of the present invention, and do not limit the present invention. Although the present invention has been described in detail with reference to the above examples, those skilled in the art should understand that the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced equivalently. Due to these modifications and replacements, the essence of the corresponding technical solutions does not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0025] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority from Chinese Patent Application No. 2019106912032, filed on July 29, 2019. The entire text of the above Chinese patent application is incorporated herein by reference.

Claims

1. A raw material preparation step S1 in which 80% to 95% electrolytic copper plate and 5% to 20% Fe element are prepared in mass percent according to a predetermined compounding ratio of copper-iron alloy, the Fe element being prepared in the form of CuFe50 mother alloy; A step S2 of filling a furnace with raw materials, which sequentially fills a furnace with a solvent, the CuFe50 mother alloy, an electrolytic copper plate, and a coating agent; A smelting step S3 in which the temperature of the smelting furnace is heated to 1420 to 1450°C to melt the copper-iron master alloy, in which gas shielding is performed at the furnace throat during melting by the temperature increase; A refining and degassing step S4 in which argon gas is passed through to perform degassing and a deoxidizing agent is used to perform deoxidation; When the temperature reaches 1300 to 1450° C., casting step S5 starts casting; When the molten metal has flowed into 70-85% of the rectangular mold, a casting step S6 is performed in which the electromagnetic stirring is turned on, the frequency is set to 3-10 Hz, the current is set to 80-100 A, the casting speed is slowly adjusted from low to high to 60-80 mm / min, and the mechanical vibration is set to 30 times / min; and (S7) performing water cooling using a mold and injecting water at a certain angle onto the ingot pulled out after solidification to perform secondary cooling.

2. The CuFe50 mother alloy is smelted by the following first to third steps: The first step is to prepare raw materials and load them into the furnace. The Cu and Fe raw materials are weighed out in a 1:1 content percentage ratio, mixed uniformly, and then loaded into a crucible and placed in a vacuum smelting furnace. The second step is vacuum induction smelting. When the vacuum level is P≦4 Pa, the power of the heater is increased to 20KW-30KW and kept warm for 5-10 minutes, the heating power of the heater is increased to 40KW-50KW and kept warm for 5-10 minutes, the heating power of the heater is increased to 60KW-70KW, and after the raw materials in the crucible are uniform from top to bottom, the heating power is reduced to 20KW, and argon gas is slowly filled into the vacuum smelting furnace. When the pressure in the furnace rises to 0.08Mpa, the filling of argon gas is stopped, and the power is increased to 70KW±5KW and smelting is continued for 1-2 minutes. The process for producing copper-iron alloy slabs by non-vacuum down-drawing continuous casting as claimed in claim 1, characterized in that the third step is pouring and unloading, in which the power of the vacuum smelting furnace is reduced to 40KW±5KW and maintained for 0.5min, pouring into the casting mold is started, and when pouring is completed, heating is turned off, and cooling is performed for 60min before unloading from the furnace.

3. The process for producing copper-iron alloy slabs by non-vacuum down-drawing continuous casting according to claim 1, characterized in that the coating material is quartz glass, the amount of which is 0.25-0.50% wt of the alloy weight, and the solvent is a mixture of sodium silicate and fluorite, the amount of which is 0.32-0.45% wt of the alloy weight.

4. The process for producing copper-iron alloy slabs by non-vacuum down-drawing continuous casting according to claim 1, characterized in that in the smelting step S3, a crucible is used to sample and detect the Fe content during smelting, and an appropriate amount of CuFe master alloy is added accordingly, thereby adjusting the molten metal composition until the Fe content reaches a target value.

5. The production process of copper-iron alloy slabs by non-vacuum down-drawing continuous casting according to claim 1, characterized in that in the refining and degassing step S4, the specific procedures of degassing by the deoxidizer are deoxidization by aluminum wire, deoxidization by CuMg alloy, and addition of titanium wire before being discharged from the furnace.

6. In the casting step S6, the amount of molten metal in the crucible of the smelting furnace is reduced to 10% or less of the original amount. and slowly decreasing the pull-down speed until it stops, and turning off the cooling water when the ingot is completely solidified.

7. The process for producing copper-iron alloy slabs by non-vacuum down-drawing continuous casting according to claim 1, characterized in that in the ingot cooling step S7, the flow rate of the cooling water is gradually increased to 6.0-8.0 m 3 / h before casting.

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