Process for improving quality of brass continuous casting ingot

Abstract

The invention provides a technology for improving the quality of a brass continuous casting ingot. The technology comprises the following steps that S1, Cu, Pb, Fe, Al and CuMg20 raw materials are weighed; s2, the raw materials are smelted, brass flux is scattered into the raw materials, slag is fished out after stirring, then the surface of molten copper is covered with graphite flakes, then CuMg20 is added into furnace water for deoxidation and desulfurization, finally, the temperature of the smelted molten copper is kept, and argon is adopted for protection; s3, the molten brass is stably introduced into a high-purity side liquid inlet graphite mold and evenly stirred, and the traction speed and the cooling rate are controlled so that a continuous and defect-free hollow cast ingot can be drawn out; and S4, saw cutting is conducted, specifically, the drawn hollow cast ingot is subjected to saw cutting and purging, and the brass hollow cast ingot is obtained. According to the method, common defects such as air holes and inclusions in the cast ingot are effectively reduced, the internal organization structure of the cast ingot is remarkably improved, the cast ingot is more compact and uniform, and meanwhile the cost input in the production process is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of alloy preparation technology, and in particular to a process for improving the quality of brass continuous casting ingots. Background Technology

[0002] Traditional brass continuous casting processes often encounter problems such as poor surface quality, uneven internal structure, and numerous porosity and inclusions, which seriously affect the quality of the ingots and their subsequent processing performance. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a process for improving the quality of brass continuous casting ingots. Through precise batching and smelting processes, the proportions of each element in the brass alloy are ensured to be accurate, while effectively removing impurities from the molten metal. The design and use of a high-purity side-inlet graphite mold not only optimizes the flow path of the molten metal and reduces turbulence and eddies within the mold, but also significantly improves the surface quality of the ingot. In the traction step, precise control of the traction speed and cooling rate enables precise regulation of the ingot solidification process, thereby further improving the internal microstructure of the ingot.

[0004] The technical solution adopted in this invention is: A process for improving the quality of brass continuous casting ingots, comprising the following steps: Step S1. Batching: By mass percentage, the brass continuous casting ingot comprises the following components: Cu 67.5-68%, Pb 0.01-0.03%, Fe 0.03-0.07%, Al 0.02-0.04%, CuMg2O 0.1-0.15%, with the remainder being Zn and unavoidable impurity elements, the total of which is 100%. Weigh out the raw materials of Cu, Pb, Fe, Al and CuMg2O according to the above components; Step S2. Smelting: The Cu, Pb, Fe and Al raw materials weighed in step S1 are added to the smelting furnace for smelting. Brass flux is evenly sprinkled in and stirred. After slag is removed, the surface of the copper liquid is covered with graphite flakes. Then CuMg2O is added to the furnace water for deoxidation and desulfurization. Finally, the smelted copper liquid is poured into the holding furnace for heat preservation and protected with inert gas. Step S3. Traction: The molten brass that has been melted and reached the predetermined temperature in step S2 is stirred evenly by a continuous casting electromagnetic stirrer, then smoothly introduced into a high-purity side-feed graphite mold and cooled. Finally, a continuous and defect-free hollow ingot is pulled out by a traction machine. Step S4. Sawing: Sawing the hollow ingot pulled out in step S3 and blowing it to obtain a brass hollow ingot.

[0005] Preferably, in the process for improving the quality of brass continuous casting ingots, the thickness of the graphite flakes covering the ingot in step S2 is 10-12 cm, the melting temperature is 1100-1160℃, and the melting time is 2 hours.

[0006] Preferably, in the process of improving the quality of brass continuous casting ingots, the brass flux in step S2 includes 65-75 parts borax, 15-20 parts glass, and 5-10 parts fluorite, and the amount of brass flux added is 0.1%-0.2% of the total mass of the raw materials.

[0007] Preferably, in the process for improving the quality of continuously cast brass ingots, the holding temperature in step S2 is 1050±10℃; the inert gas is argon, and the argon flow rate is 10-15 L / min. 2 .

[0008] Preferably, in the process for improving the quality of brass continuous casting ingots, in step S3, the high-purity side-inlet graphite mold includes a mold body, a core rod is provided in the middle of the mold along the length direction, a flow channel is provided between the mold body and the core rod, and an inlet and an outlet are provided on the surface of the mold body, with the inlet and the flow channel being interconnected.

[0009] Preferably, the process for improving the quality of brass continuous casting ingots includes: both the inner and outer surfaces of the mold body are coated with silicon carbide, the roughness of the inner wall of the mold body is ≤0.6μm, the inclination angle of the core rod is 1.75°, and the vent is perpendicular to the horizontal plane of the mold body.

[0010] Preferably, in the process for improving the quality of brass continuous casting ingots, the thickness of the silicon carbide coating is 0.1~0.3mm.

[0011] Preferably, in the process of improving the quality of brass continuous casting ingots, the traction speed of the traction machine in step S3 is 145-160 mm / min, the cooling water flow rate is ≤2500 L / h, and the return water temperature is ≤50℃.

[0012] Advantages of this invention: The present invention provides a process for improving the quality of brass continuous casting ingots. It designs a novel high-purity side-inlet graphite mold, optimizes the surface quality of the ingot, uses an electronic stirring device in the crystallizer to reduce component segregation, and configures reasonable traction parameters and controls the cooling rate to ensure that the ingot forms a uniform and fine grain structure during solidification. The present invention effectively reduces common defects in ingots such as porosity and inclusions, significantly improves the internal structure of the ingot, making it more dense and uniform, and at the same time greatly reduces the cost input in the production process. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the high-purity side-inlet graphite mold of the present invention. Detailed Implementation

[0014] The present invention will be further described below with reference to specific embodiments.

[0015] Example 1 A process for improving the quality of brass continuous casting ingots, comprising the following steps: Step S1. Batching: By mass percentage, the brass continuous casting ingot comprises the following components: Cu 67.5-68%, Pb 0.01-0.03%, Fe 0.03-0.07%, Al 0.02-0.04%, CuMg2O 0.1-0.15%, with the remainder being Zn and unavoidable impurity elements, the total of which is 100%. Weigh out the raw materials of Cu, Pb, Fe, Al and CuMg2O according to the above components; Step S2. Smelting: The Cu, Pb, Fe, and Al raw materials weighed in Step S1 are added to a smelting furnace for smelting. Brass flux is evenly sprinkled in and stirred, then slag is skimmed off. The brass flux consists of 70 parts borax, 20 parts glass, and 10 parts fluorite. The amount of brass flux added is 0.1% of the total mass of the raw materials. Then, graphite flakes are placed on the surface of the molten copper to a thickness of 12 cm. The smelting temperature is 1150℃, and the smelting time is 2 hours. Then, CuMg2O is added to the molten copper for deoxidation and desulfurization. Samples of the molten copper are taken for pre-furnace composition analysis to ensure that the chemical composition meets the requirements. Finally, the smelted molten copper is poured into a holding furnace for heat preservation, using inert gas argon protection. The holding temperature is 1050℃, and the argon flow rate is 13 L / min·m. 2 ; Step S3. Traction: The molten brass that has been melted and reached the predetermined temperature in step S2 is stirred evenly by a continuous casting electromagnetic stirrer, and then smoothly introduced into a φ90×25mm high-purity side-inlet graphite mold. The inner and outer surfaces of the high-purity side-inlet graphite mold are coated with silicon carbide. The high-purity side-inlet graphite mold is connected to the primary and secondary cooling water assemblies. Finally, the traction speed and cooling rate are controlled by the traction machine to traction out a continuous and defect-free hollow ingot. The traction speed is 150mm / min, the cooling water flow rate is 2300L / h, and the return water temperature is 32℃. like Figure 1 The high-purity side-inlet graphite mold includes a mold body 1, a core rod 2 arranged along the length of the mold in the middle, a flow channel 3 arranged between the mold body 1 and the core rod 2, an inlet 4 and an outlet 5 arranged on the surface of the mold body 1, and the inlet 4 and the flow channel 3 are interconnected; both the inner and outer surfaces of the mold body 1 are coated with silicon carbide, the thickness of the silicon carbide coating is 0.2 mm, the roughness of the inner wall of the mold body 1 is ≤0.6 μm, the inclination angle of the core rod 2 is 1.75°, and the outlet 5 is perpendicular to the horizontal plane of the mold body 1.

[0016] Step S4. Sawing: The hollow ingot pulled out in step S3 is precisely sawn to the predetermined length, and metal debris is blown away to ensure that the sawn surface is flat and smooth. The surface of the hollow ingot is thoroughly inspected to ensure that there are no defects such as cracks, peeling, or pores, and that the dimensions and chemical composition meet the requirements, thus obtaining a brass hollow ingot.

[0017] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that: in step S1, the alloy of Comparative Example 1 does not contain Al and CuMg2O, and the missing amount is made up by the remaining components in the proportion of Example 1; Step S3. Traction: The molten brass that has been melted and reached the predetermined temperature in step S2 is smoothly introduced into a φ90×25mm high-purity side-inlet graphite mold. The surface of the high-purity side-inlet graphite mold is not coated with silicon carbide. The high-purity side-inlet graphite mold is connected to the primary and secondary cooling water assemblies. Finally, the traction speed and cooling rate are controlled by the traction machine to traction out a continuous and defect-free hollow ingot. The traction speed is 150mm / min, the cooling water flow rate is ≤2300L / h, and the return water temperature is 32℃. The high-purity side-inlet graphite mold includes a mold body 1, a core rod 2 arranged along the length of the mold in the middle, a flow channel 3 arranged between the mold body 1 and the core rod 2, an inlet 4 and an outlet 5 arranged on the surface of the mold body 1, and the inlet 4 and the flow channel 3 are interconnected; the surface of the mold body 1 is coated with silicon carbide, the inner wall roughness of the mold body 1 is ≤0.6μm, the inclination angle of the core rod 2 is 1°, and the outlet 5 is perpendicular to the horizontal plane.

[0018] The chemical composition, product yield, and mold usage records of the brass hollow ingots of Example 1 and Comparative Example 1 were compared. The chemical composition must meet the requirements of H68 in standard GB / T 5231-2022. The test points were the ends of the ingot cut to length. The chemical composition test results of Example 1 and Comparative Example 1 are shown in Table 1.

[0019] Table 1

[0020] As can be seen from Table 1 above, the Cu content at both ends of the φ90*25*9m hollow ingot of grade H68 after treatment in Example 1 is relatively uniform, and the segregation is significantly improved.

[0021] The yield rate and mold usage of Example 1 and Comparative Example 1 are shown in Table 2.

[0022] Table 2

[0023] As can be seen from Table 2 above, the yield of H68 hollow ingots after treatment in Example 1 is significantly improved, greatly reducing defects such as porosity and inclusions on the surface of the ingots. After applying a silicon carbide coating to the surface of the side-entry graphite mold, the service life is extended, and the cost input in the production process is reduced.

[0024] Example 2 A process for improving the quality of brass continuous casting ingots, comprising the following steps: Step S1. Batching: By mass percentage, the brass continuous casting ingot comprises the following components: Cu 67.5-68%, Pb 0.01-0.03%, Fe 0.03-0.07%, Al 0.02-0.04%, CuMg2O 0.1-0.15%, with the remainder being Zn and unavoidable impurity elements, the total of which is 100%. Weigh 3000 kg of Cu, Pb, Fe, Al and CuMg2O raw materials that have been screened, cut into small pieces and dried according to the above components; Step S2. Smelting: The Cu, Pb, Fe, and Al raw materials weighed in Step S1 are added to a single-flow brass smelting furnace for smelting. After the metal is completely melted, brass flux is evenly sprinkled in, stirred, and then slag is removed. The brass flux includes 70 parts borax, 20 parts glass, and 10 parts fluorite. The amount of brass flux added is 0.1% of the total mass of the raw materials. Then, graphite flakes are covered on the surface of the copper liquid to a thickness of 12 cm. The smelting temperature is 1150℃, and the smelting time is 2 hours. Then, CuMg2O is added to the furnace water for deoxidation and desulfurization. Samples of the copper liquid are taken for pre-furnace composition analysis to ensure that the chemical composition requirements are met. Finally, the smelted copper liquid is poured into a holding furnace for heat preservation, using inert gas argon protection. The holding temperature is 1050℃, and the argon flow rate is 12 L / min·m. 2 ; Step S3. Traction: The molten brass that has been melted and reached the predetermined temperature in step S2 is stirred evenly by a continuous casting electromagnetic stirrer, and then smoothly introduced into a φ85×15mm high-purity side-inlet graphite mold. The surface of the high-purity side-inlet graphite mold is coated with a silicon carbide coating. The high-purity side-inlet graphite mold is connected to the primary and secondary cooling water assemblies. Finally, the traction speed and cooling rate are controlled by the traction machine to traction out a continuous and defect-free hollow ingot. The traction speed is 155mm / min, the cooling water flow rate is 2300L / h, and the return water temperature is 35℃. like Figure 1The high-purity side-inlet graphite mold includes a mold body 1, a core rod 2 arranged along the length of the mold in the middle, a flow channel 3 arranged between the mold body 1 and the core rod 2, an inlet 4 and an outlet 5 arranged on the surface of the mold body 1, and the inlet 4 and the flow channel 3 are interconnected; both the inner and outer surfaces of the mold body 1 are coated with silicon carbide, the thickness of the silicon carbide coating is 0.2 mm, the roughness of the inner wall of the mold body 1 is ≤0.6 μm, the inclination angle of the core rod 2 is 1.75°, and the outlet 5 is perpendicular to the horizontal plane of the mold body 1.

[0025] Step S4. Sawing: The hollow ingot pulled out in step S3 is precisely sawn to the predetermined length, and metal debris is blown away to ensure that the sawn surface is flat and smooth. The surface of the hollow ingot is thoroughly inspected to ensure that there are no defects such as cracks, peeling, or pores, and that the dimensions and chemical composition meet the requirements, thus obtaining a brass hollow ingot.

[0026] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A process for improving the quality of brass continuous casting ingots, characterized in that: Includes the following steps: Step S1. Batching: By mass percentage, the brass continuous casting ingot comprises the following components: Cu 67.5-68%, Pb 0.01-0.03%, Fe 0.03-0.07%, Al 0.02-0.04%, CuMg2O 0.1-0.15%, with the remainder being Zn and unavoidable impurity elements, the total of which is 100%. Weigh out the raw materials of Cu, Pb, Fe, Al and CuMg2O according to the above components; Step S2. Smelting: The Cu, Pb, Fe and Al raw materials weighed in step S1 are added to the smelting furnace for smelting. Brass flux is evenly sprinkled in and stirred. After slag is removed, the surface of the copper liquid is covered with graphite flakes. Then CuMg2O is added to the furnace water for deoxidation and desulfurization. Finally, the smelted copper liquid is poured into the holding furnace for heat preservation and protected with inert gas. Step S3. Traction: The molten brass that has been melted and reached the predetermined temperature in step S2 is stirred evenly by a continuous casting electromagnetic stirrer, then smoothly introduced into a high-purity side-feed graphite mold and cooled. Finally, a continuous and defect-free hollow ingot is pulled out by a traction machine. Step S4. Sawing: Sawing the hollow ingot pulled out in step S3 and blowing it to obtain a brass hollow ingot.

2. The process for improving the quality of brass continuous casting ingots according to claim 1, characterized in that: In step S2, the thickness of the graphite flakes covering the surface is 10-12 cm, the melting temperature is 1100-1160℃, and the melting time is 2 hours.

3. The process for improving the quality of brass continuous casting ingots according to claim 1, characterized in that: In step S2, the holding temperature is 1050±10℃; the inert gas is argon, and the argon flow rate is 10⁻¹⁵ L / min. 2 .

4. The process for improving the quality of brass continuous casting ingots according to claim 1, characterized in that: In step S2, the brass flux includes 65-75 parts borax, 15-20 parts glass, and 5-10 parts fluorite. The amount of brass flux added is 0.1%-0.2% of the total mass of the raw materials.

5. The process for improving the quality of brass continuous casting ingots according to claim 1, characterized in that: In step S3, the high-purity side-inlet graphite mold includes a mold body (1), a core rod (2) is set in the middle of the mold along the length direction, a flow channel (3) is set between the mold body (1) and the core rod (2), and an inlet (4) and an outlet (5) are set on the surface of the mold body (1). The inlet (4) and the flow channel (3) are interconnected.

6. The process for improving the quality of brass continuous casting ingots according to claim 1, characterized in that: The inner and outer surfaces of the mold body (1) are coated with silicon carbide. The roughness of the inner wall of the mold body (1) is ≤0.6μm. The inclination angle of the core rod (2) is 1.75°. The vent (5) is perpendicular to the horizontal plane of the mold body (1).

7. The process for improving the quality of brass continuous casting ingots according to claim 6, characterized in that: The thickness of the silicon carbide coating is 0.1~0.3mm.

8. The process for improving the quality of brass continuous casting ingots according to claim 1, characterized in that: In step S3, the traction speed of the traction machine is 145-160 mm / min, the cooling water flow rate is ≤2500 L / h, and the return water temperature is ≤50℃.

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