A brake disc air pressure ladle precision casting process, brake disc and automobile

Abstract

This invention belongs to the field of brake disc casting technology and discloses a precise casting process for brake discs using a pneumatic ladle, a brake disc itself, and an automobile. The steps include: smelting two batches of molten iron according to the standard brake disc composition, ensuring the composition of the molten iron falls within the corresponding range for the standard brake disc; using the first batch of molten iron for furnace cleaning and the second batch for brake disc casting; distributing and injecting the first batch of molten iron into a pneumatic ladle for low-level circulation and furnace cleaning, and adding the next batch of cleaning molten iron after completion; testing the composition of the molten iron in the ladle after each round of cleaning, and casting a scrap brake disc after the composition is close to the standard value; stopping the process after the molten iron composition is qualified; after furnace cleaning, casting the brake disc, and extracting the molten iron from the ladle at preset intervals to adjust and control the carbon content, thus completing the brake disc casting. This invention eliminates the need to drain the molten iron from the ladle, avoiding damage to the pneumatic ladle; ensures consistent brake disc material; provides strong production continuity and high efficiency; and improves product quality.

Description

Technical Field

[0001] This invention belongs to the field of brake disc casting technology, specifically relating to a precise casting process for brake discs using pneumatic casting ladles, brake discs, and automobiles. Background Technology

[0002] As a core safety component of the vehicle braking system, the metallographic structure, mechanical properties, dimensional accuracy, and batch consistency of automotive brake discs directly determine the vehicle's braking safety and service life. This places extremely high technical demands on the stability of the molten iron composition, pouring precision, and production controllability in the casting process. In existing large-scale brake disc casting production, the process of melting in a medium-frequency furnace with an automatic molten iron pouring ladle is the mainstream production solution in the industry. This process has a simple overall operation, convenient equipment maintenance, and flexible molten iron material adjustment, making it suitable for most conventional brake disc mass production scenarios. Therefore, it has the widest application range and the highest adoption rate in the industry.

[0003] Compared to the traditional automatic molten iron pouring ladle process, the pouring system of medium frequency furnace melting combined with gas pressure ladle has significant precision advantages. This process can achieve precise control of pouring temperature, effectively avoid casting defects caused by pouring temperature fluctuations, and greatly improve the batch consistency of the internal metallographic structure, external dimensional accuracy, and comprehensive mechanical properties of the formed brake disc. It can significantly improve the finished product quality and yield of brake discs, and is more adaptable to high-end, high-quality brake disc production scenarios.

[0004] However, the current pneumatic ladle casting process suffers from insurmountable technical shortcomings that severely restrict the large-scale and flexible application of this high-precision technology. Specifically, the structural characteristics of the pneumatic ladle result in a certain amount of residual molten iron remaining inside after operation. During the alternating production of multiple types and grades of brake discs, it is impossible to quickly switch between molten iron of different compositions and grades. Furthermore, after prolonged heat preservation and settling, the alloy composition of the residual molten iron inside the ladle shifts, deviating from the material standards for conventional brake disc production. This significantly increases the difficulty of material switching and molten iron composition adjustment, resulting in extremely low composition calibration efficiency.

[0005] To address the challenge of material switching, the industry's conventional approach is to completely purge the residual molten iron from the pneumatic ladle and then remelt it with a matching grade of molten iron. However, this method not only results in significant waste of molten iron and a substantial increase in production costs, but the repeated pneumatic ladle evacuation and refilling also exacerbates ladle wear, directly shortening equipment lifespan and increasing maintenance and replacement costs. For a long time, the industry has lacked efficient and low-cost solutions for molten iron material switching and composition calibration. This has prevented the pneumatic ladle casting process from fully leveraging its core advantages of high precision and consistency, making it difficult to meet the current market demands for diverse, small-batch, and flexible brake disc production, thus severely limiting its application scenarios.

[0006] In summary, the existing pneumatic ladle casting process for brake discs suffers from numerous technical defects, such as difficulty in switching molten iron materials, excessive residual molten iron content, poor production flexibility, high production costs, and significant equipment wear and tear. There is an urgent need to develop a new integrated production process to address these industry pain points and balance the advantages of high-precision casting with the demands for flexible production. Summary of the Invention

[0007] This invention provides a precise casting process for brake discs using a pneumatic ladle, along with the brake discs themselves and the automobile. It enables rapid switching between different materials in the pneumatic ladle without completely emptying the ladle, thus avoiding damage to the pneumatic ladle and saving production costs. A systematic furnace cleaning process precisely calibrates the alloy composition of the molten iron, controlling carbon content fluctuations within ±0.05%, ensuring high material consistency across batches of brake discs. A dynamic carbon loss compensation mechanism is established to correct the molten iron composition in real time, adapting to continuous casting conditions using a pneumatic ladle, resulting in strong production continuity and high efficiency. The cast products meet all metallographic and mechanical property standards, pass bench tests, and demonstrate improved product quality consistency.

[0008] The specific details of the plan are as follows:

[0009] A precision casting process for brake discs using pneumatic casting ladles, comprising the following steps:

[0010] S1. Preparation for smelting two furnaces of molten iron: Two furnaces of molten iron are smelted simultaneously, both according to the standard composition of the brake disc. The composition of the molten iron obtained from the smelting falls within the corresponding composition range of the standard brake disc. The first furnace of molten iron is used for furnace cleaning, and the second furnace of molten iron is used for the formal casting of the brake disc.

[0011] S2. Graded furnace cleaning: The first batch of molten iron is poured into a transfer ladle and then injected into a pneumatic ladle for low-level circulation and replacement cleaning. After the ladle level drops to a low level again, the next batch of molten iron is added, and the circulation and replacement operation is repeated. After each round of molten iron circulation and replacement is completed, the composition of the molten iron in the pneumatic ladle is sampled and tested. When the deviation between the molten iron composition content and the standard value of the brake disc composition content is less than the preset deviation value, the current molten iron is used to cast a scrap brake disc. Casting is stopped after the content of each component of the molten iron enters the range of the standard brake disc composition content.

[0012] S3. Dynamic composition compensation and continuous casting: After the furnace cleaning process is completed, the brake disc casting is officially started. Every preset time, a sample of molten iron in the pneumatic ladle is taken. Based on the carbon loss data, the carbon additive is added to adjust the carbon content of the molten iron from the medium frequency furnace. Finally, the fluctuation of the carbon content of the molten iron in the pneumatic ladle is controlled within the set range, and the brake disc casting is completed.

[0013] The invention is divided into three core processes: material preparation and smelting, furnace cleaning and replacement, and continuous casting. By preparing molten iron in two furnaces in advance, graded furnace cleaning, and dynamic composition compensation, the problems of material switching and composition loss control are solved.

[0014] After two furnaces of molten iron are smelted, the first furnace is transferred to a transfer ladle. The production line mode is switched to a dual-furnace single-line operation mode, allowing the molten iron from the induction furnace to be continuously transported to the pneumatic ladle, ensuring a continuous supply of molten iron. The first furnace of molten iron can be divided into 10 transfer ladles, which are then transported to the pouring station and poured into the pneumatic ladle for furnace cleaning. Under safe operating conditions, the remaining molten iron in the pneumatic ladle is poured to the minimum allowable liquid level. The first ladle of molten iron is then poured into the ladle, and pouring is carried out simultaneously. Once the ladle level drops to a low level again, the next ladle of molten iron is added, and the cycle of replenishing molten iron and pouring at a low level is repeated.

[0015] Composition sampling and testing: After each round of molten iron circulation and replacement, the molten iron in the pneumatic ladle is immediately subjected to spectral analysis and thermal analysis to track changes in core elements such as carbon, silicon, manganese, and chromium in real time until all indicators of the molten iron enter the qualified range of the brake disc.

[0016] After the composition of the scrap mold is close to the standard value during auxiliary calibration, that is, when the deviation between the molten iron content and the standard value of the brake disc content is less than the preset deviation value, the current molten iron is used to pour the scrap mold brake disc to further and thoroughly replace the residual old molten iron in the ladle flow channel and pipeline dead corners. Pouring the scrap mold with the composition close to the standard and the preset deviation value is a traditional and mature furnace cleaning method, which is known to any foundry and ordinary technicians and is common knowledge, so it will not be elaborated here.

[0017] During the furnace cleaning stage, the tapping temperature of molten iron is set at 1500℃. During the smelting process, carbon additives are added as needed to offset carbon loss during the transfer and settling of molten iron.

[0018] Through the above graded furnace cleaning operation, the original substandard molten iron in the pneumatic ladle is completely replaced, and the overall composition and metallurgical state of the molten iron meet the requirements for brake disc casting, thus solving the problems of difficult material switching and uneven composition from the source.

[0019] Furthermore, in step S1, the composition content of the standard brake disc, by mass percentage, includes: C 3.25%-3.35%, Si 1.55%-1.75%, Mn 0.25%-0.35%, S 0.08%-0.10%, Cr 0.23%-0.27%, Ti ≤0.015%, V ≤0.01%, Zn ≤0.01%, with the balance being Fe and unavoidable impurities.

[0020] The preferred standard component content of brake discs in this invention is only an exemplary ratio and is not a limited and unique control standard. In actual production, the target control range of each element can be adjusted according to different vehicle models, loads and performance requirements. The implementation methods of different component specifications for various types of brake discs all fall within the protection scope of this technical solution and do not constitute a limitation on the protection scope of this invention.

[0021] Furthermore, in step S1, two furnaces of molten iron are smelted simultaneously in a medium-frequency furnace. The raw materials include pig iron, high-purity cast iron blocks, pure recycled materials, carbon raisers, and silicon carbide. The raw materials are weighed according to the composition of the standard brake disc and then put into the furnace for smelting. During the smelting process, the carbon content is controlled at the upper limit of 3.35% of the content range of each component of the standard brake disc, and the manganese content is set at 0.30%. The target carbon content of the gas pressure ladle is controlled at 3.30%, the chromium content is controlled at 0.25%, and the copper content is controlled at 0.35%. After the molten iron is inoculated, the manganese content is uniformly adjusted to 0.30%.

[0022] In the preparation process of dual-furnace molten iron smelting, this invention employs a medium-frequency furnace to simultaneously smelt two batches of qualified molten iron. The first batch serves as molten iron for furnace cleaning, while the second batch is used for the formal casting of the brake disc. Both batches of molten iron are prepared, smelted, and subjected to spectral analysis according to the standard composition for brake discs, ensuring that the initial composition meets process requirements and providing qualified molten iron for subsequent furnace cleaning and casting. The method for controlling the content of each component is existing technology, involving the addition of appropriate materials for adjustment, such as graphite carburizing agents for increasing carbon, ferromanganese for increasing manganese, and ferrosilicon inoculants for adjusting silicon, etc., which will not be elaborated here.

[0023] High-purity cast iron blocks, also known as pure briquettes, are low in sulfur and phosphorus, free of oxide scale and mud and sand inclusions, and are used as raw materials for furnace cleaning.

[0024] The standard brake disc composition of this invention, by mass percentage, includes: C 3.25%-3.35%, Si 1.55%-1.75%, Mn 0.25%-0.35%, S 0.08%-0.10%, Cr 0.23%-0.27%, Ti ≤0.015%, V ≤0.01%, Zn ≤0.01%, with the balance being Fe and unavoidable impurities. The raw materials are configured according to the standard brake disc composition: 10 tons of pure bales, 1.5 tons of pure recycled material, 2 tons of pig iron, 230 kg of carbonizer, and 280 kg of silicon carbide. Two batches of molten iron are simultaneously smelted in a medium-frequency furnace. The composition of both the first and second batches of molten iron falls within the range of the standard brake disc composition.

[0025] Furthermore, in step S1, the tapping temperature of the first batch of molten iron is set to 1500℃, and a carbonizer is added during the smelting process based on the results of the molten iron composition test.

[0026] Furthermore, in step S2, when using the current molten iron to cast the scrap brake disc, the cumulative number of castings is 4-10 boxes, and the casting time for each box is 5 seconds. When the content of each component of the molten iron in the pneumatic ladle enters the range of the standard brake disc component content, the casting is stopped.

[0027] Generally, the molten iron in each pneumatic ladle can be used to cast 10 boxes of scrap brake discs. Casting the scrap brake discs can completely replace the residual old molten iron in the ladle flow channel and dead corners of the pipeline.

[0028] Furthermore, in step S3, when formally casting the brake disc, the temperature of the molten iron is ≤1403℃, and the inoculation rate is maintained at 14±1g / s.

[0029] Furthermore, in step S3, a sample of molten iron is taken from the gas pressure ladle every 10 minutes, and the carbon content of the molten iron from the medium-frequency furnace is adjusted based on the burn-off data.

[0030] Furthermore, in step S3, the carbon content of the molten iron in the pneumatic ladle is ultimately controlled within the range of ±0.05%.

[0031] A brake disc is prepared using the aforementioned brake disc pneumatic casting process.

[0032] An automobile includes the aforementioned brake disc.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] 1. Enables rapid switching of molten iron of different materials in the pneumatic ladle without completely emptying the ladle, thus avoiding damage to the pneumatic ladle and saving production costs;

[0035] 2. By using a systematic furnace cleaning process to precisely calibrate the alloy composition of molten iron, the carbon content fluctuation of molten iron is controlled within ±0.05%, ensuring a high degree of consistency in the material of batch brake discs;

[0036] 3. Establish a dynamic compensation mechanism for carbon loss, correct the composition of molten iron in real time, adapt to the continuous pouring condition of pneumatic ladle, and achieve strong production continuity and high production efficiency.

[0037] 4. The metallographic structure and mechanical properties of the finished brake discs fully meet the standards, the bench test is passed, and the consistency of product quality is improved. Attached Figure Description

[0038] 1. Figure 1 This is a metallographic image of the uncorroded brake disc obtained by casting according to the present invention.

[0039] 2. Figure 2 The image shows the metallographic structure of the brake disc obtained by casting according to the present invention after corrosion. Detailed Implementation

[0040] To make the technical problem solved by this invention, the technical solution adopted, and the technical effects achieved clearer, the technical solution of this invention will be further described below through specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining this invention and are not intended to limit it.

[0041] This invention provides a precise casting process for brake discs using pneumatic casting ladles, comprising the following steps:

[0042] S1. Preparation for smelting two furnaces of molten iron: Two furnaces of molten iron are smelted simultaneously, both according to the standard composition of the brake disc. The composition of the molten iron obtained from the smelting falls within the corresponding composition range of the standard brake disc. The first furnace of molten iron is used for furnace cleaning, and the second furnace of molten iron is used for the formal casting of the brake disc.

[0043] S2. Graded furnace cleaning: The first batch of molten iron is poured into a transfer ladle and then injected into a pneumatic ladle for low-level circulation and replacement cleaning. After the ladle level drops to a low level again, the next batch of molten iron is added, and the circulation and replacement operation is repeated. After each round of molten iron circulation and replacement is completed, the composition of the molten iron in the pneumatic ladle is sampled and tested. When the deviation between the molten iron composition content and the standard value of the brake disc composition content is less than the preset deviation value, the current molten iron is used to cast a scrap brake disc. Casting is stopped after the content of each component of the molten iron enters the range of the standard brake disc composition content.

[0044] S3. Dynamic composition compensation and continuous casting: After the furnace cleaning process is completed, the brake disc casting is officially started. Every preset time, a sample of molten iron in the pneumatic ladle is taken. Based on the carbon loss data, the carbon additive is added to adjust the carbon content of the molten iron from the medium frequency furnace. Finally, the fluctuation of the carbon content of the molten iron in the pneumatic ladle is controlled within the set range, and the brake disc casting is completed.

[0045] In step S1, the composition of the standard brake disc, by mass percentage, includes: C 3.25%-3.35%, Si 1.55%-1.75%, Mn 0.25%-0.35%, S 0.08%-0.10%, Cr 0.23%-0.27%, Ti ≤0.015%, V ≤0.01%, Zn ≤0.01%, with the balance being Fe and unavoidable impurities.

[0046] In step S1, two furnaces of molten iron are smelted simultaneously in a medium-frequency furnace. The raw materials include pig iron, high-purity cast iron blocks, pure recycled materials, carbon raisers, and silicon carbide. The raw materials are weighed according to the composition of the standard brake disc and then put into the furnace for smelting. During the smelting process, the carbon content is controlled at the upper limit of 3.35% of the content range of each component of the standard brake disc, and the manganese content is set at 0.30%. The target carbon content of the gas pressure ladle is controlled at 3.30%, the chromium content is controlled at 0.25%, and the copper content is controlled at 0.35%. After the molten iron is inoculated, the manganese content is uniformly adjusted to 0.30%.

[0047] In step S1, the tapping temperature of the first batch of molten iron is set to 1500℃, and a carbonizer is added during the smelting process based on the results of the molten iron composition test.

[0048] In step S2, when using the current molten iron to cast the scrap brake disc, the cumulative number of castings is 4-10 boxes, and the casting time for each box is 5 seconds. When the content of each component of the molten iron in the pneumatic ladle enters the range of the standard brake disc component content, the casting is stopped.

[0049] In step S3, when the brake disc is formally cast, the temperature of the molten iron is ≤1403℃, and the inoculation rate remains constant at 14±1g / s.

[0050] In step S3, a sample of molten iron from the gas pressure ladle is taken every 10 minutes. Based on the burn-off data, the carbon content of the molten iron from the medium-frequency furnace is adjusted, and the fluctuation of the carbon content of the molten iron in the gas pressure ladle is finally controlled within ±0.05%.

[0051] The present invention also provides a brake disc, which is prepared by applying the aforementioned brake disc pneumatic casting process.

[0052] The present invention also provides an automobile, including the aforementioned brake disc.

[0053] The following examples illustrate... Figure 1 and Figure 2 The present invention will be described in detail below:

[0054] Example 1:

[0055] Two batches of qualified molten iron are smelted simultaneously in a medium-frequency furnace. The raw materials for each batch of molten iron are 10 tons of pure lumps (i.e., high-purity cast iron lumps), 1.5 tons of pure recycled material, 2 tons of pig iron, 230 kg of carbon raiser, and 280 kg of silicon carbide. During the smelting process, the carbon content is controlled at the upper limit of 3.35% of the content range of each component in the standard brake disc, and the manganese content is set at 0.30%. The target carbon content for the gas pressure ladle is controlled at 3.30%, and the chromium content is controlled at 0.25%. After inoculation treatment, the manganese content of the molten iron is uniformly adjusted to 0.30%.

[0056] After the molten iron was smelted, the first and second batches of molten iron were subjected to spectral analysis. The composition of the first batch of molten iron, by mass percentage, was: C 3.33%, Si 1.67%, Mn 0.29%, S 0.08%, Cr 0.26%, Ti 0.003%, V 0.007%, Zn 0.004%, with the balance being Fe and unavoidable impurities. The composition of the second batch of molten iron, by mass percentage, was: C 3.34%, Si 1.64%, Mn 0.3%, S 0.09%, Cr 0.24%, Ti 0.007%, V 0.008%, Zn 0.004%, with the balance being Fe and unavoidable impurities. The composition of the molten iron obtained from the smelting both fell within the composition range corresponding to the standard brake disc.

[0057] On-site furnace cleaning operation: The first batch of molten iron is used for furnace cleaning. The production line is switched to a dual-furnace single-line mode, and the molten iron is transported to the pneumatic ladle. The remaining molten iron in the ladle is poured to the minimum safe level. Molten iron is added in multiple batches, and the level is lowered after each batch of molten iron is added. The operation is repeated. After each cycle, samples are taken for spectral and thermal analysis to monitor composition changes. The temperature of the first batch of molten iron is maintained at 1500℃. Carburizing agent is added as needed according to the composition test results to complete the entire furnace cleaning process. After the composition meets the standards, 10 boxes of scrap mold products are continuously poured, with each box poured for 5 seconds. After the furnace is cleaned and qualified, batch pouring begins. The pouring temperature of the molten iron is controlled at or below 1403℃, and the inoculation rate remains constant at 14±1g / s. The composition of the molten iron used for pouring is: C 3.29%, Si 2.05%, Mn 0.6%, P 0.019%, S 0.083%, Cr 0.24%, Cu 0.33%, Ti 0.012%, Sn 0.064%, Ni 0.014%, Mo 0.004%, Ti 0.012%, V 0.007%, Zn 0.084%, with the balance being Fe and unavoidable impurities. The pouring temperature of the molten iron is controlled at or below 1403℃, and the inoculation rate remains constant at 14±1g / s. During the pouring process, carbon loss will continuously occur in the molten iron, resulting in composition fluctuations. Therefore, a sample of molten iron from the gas-pressure ladle was taken every 10 minutes to summarize the carbon loss pattern. Based on the loss data, the carbon content of the molten iron tapped from the induction furnace was adjusted synchronously to dynamically compensate for carbon loss in real time, ultimately strictly controlling the fluctuation of carbon content in the molten iron within ±0.05%. After casting, the performance of the finished brake disc was tested, and the metallographic image of the brake disc is shown below. Figure 1 and Figure 2 Hardness tests were performed on different points of brake disc 1 and brake disc 2, and the results are shown in Table 1. Brake Disc Hardness Table:

[0058] Table 1

[0059]

[0060] Weft compressibility strength tests were performed at different points on brake discs 1 and 2, resulting in Table 2, Brake Disc Weft Compressibility Table.

[0061] Table 2

[0062]

[0063] Specialized bench tests were conducted on the brake discs for hot cracking, hot deformation, and high load. All test items met the evaluation indicators, and the tests were passed. The above test results demonstrate that the brake discs cast using the precise air-pressure casting process of this invention achieve full compliance with standards in terms of metallographic structure and mechanical properties, pass the bench tests, and improve product quality consistency.

[0064] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A precise casting process for brake discs using pneumatic casting ladles, characterized by the following steps: include: S1. Preparation for smelting two furnaces of molten iron: Two furnaces of molten iron are smelted simultaneously, both according to the standard composition of the brake disc. The composition of the molten iron obtained from the smelting falls within the corresponding composition range of the standard brake disc. The first furnace of molten iron is used for furnace cleaning, and the second furnace of molten iron is used for the formal casting of the brake disc. S2. Graded furnace cleaning: The first batch of molten iron is poured into a transfer ladle and then injected into a pneumatic ladle for low-level circulation and replacement cleaning. After the ladle level drops to a low level again, the next batch of molten iron is added, and the circulation and replacement operation is repeated. After each round of molten iron circulation and replacement is completed, the composition of the molten iron in the pneumatic ladle is sampled and tested. When the deviation between the molten iron composition content and the standard value of the brake disc composition content is less than the preset deviation value, the current molten iron is used to cast a scrap brake disc. Casting is stopped after the content of each component of the molten iron enters the range of the standard brake disc composition content. S3. Dynamic composition compensation and continuous casting: After the furnace cleaning process is completed, the brake disc casting is officially started. Every preset time, a sample of molten iron in the pneumatic ladle is taken. Based on the carbon loss data, the carbon additive is added to adjust the carbon content of the molten iron from the medium frequency furnace. Finally, the fluctuation of the carbon content of the molten iron in the pneumatic ladle is controlled within the set range, and the brake disc casting is completed.

2. The brake disc pneumatic casting process according to claim 1, characterized in that, In step S1, the composition of the standard brake disc, by mass percentage, includes: C 3.25%-3.35%, Si 1.55%-1.75%, Mn 0.25%-0.35%, S 0.08%-0.10%, Cr 0.23%-0.27%, Ti ≤0.015%, V ≤0.01%, Zn ≤0.01%, with the balance being Fe and unavoidable impurities.

3. The precise casting process for brake disc pneumatic casting ladle according to claim 1, characterized in that, In step S1, two furnaces of molten iron are smelted simultaneously in a medium-frequency furnace. The raw materials include pig iron, high-purity cast iron blocks, pure recycled materials, carbon raisers, and silicon carbide. The raw materials are weighed according to the composition of the standard brake disc and then put into the furnace for smelting. During the smelting process, the carbon content is controlled at the upper limit of 3.35% of the content range of each component of the standard brake disc, and the manganese content is set at 0.30%. The target carbon content of the gas pressure ladle is controlled at 3.30%, the chromium content is controlled at 0.25%, and the copper content is controlled at 0.35%. After the molten iron is inoculated, the manganese content is uniformly adjusted to 0.6%.

4. The brake disc pneumatic casting process according to claim 1, characterized in that, In step S1, the tapping temperature of the first batch of molten iron is set to 1500℃, and a carbonizer is added during the smelting process based on the results of the molten iron composition test.

5. The brake disc pneumatic casting process according to claim 1, characterized in that, In step S2, when using the current molten iron to cast the scrap brake disc, the cumulative number of castings is 4-10 boxes, and the casting time for each box is 5 seconds. When the content of each component of the molten iron in the pneumatic ladle enters the range of the standard brake disc component content, the casting is stopped.

6. The brake disc pneumatic casting process according to claim 1, characterized in that, In step S3, when formally casting the brake disc, the temperature of the molten iron is ≤1403℃, and the inoculation rate is maintained at 14±1g / s.

7. The brake disc pneumatic casting process according to claim 1, characterized in that, In step S3, a sample of molten iron is taken from the gas pressure ladle every 10 minutes, and the carbon content of the molten iron from the medium frequency furnace is adjusted based on the burn-off data.

8. The brake disc pneumatic casting process according to claim 1, characterized in that, In step S3, the carbon content of the molten iron in the pneumatic ladle is ultimately controlled within the range of ±0.05%.

9. A brake disc, characterized in that, The brake disc is prepared using the precise casting process described in any one of claims 1-8.

10. A car, characterized in that, Includes the brake disc as described in claim 9.

Images