High-strength and high-toughness automobile caliper mold and production method

Abstract

The invention belongs to the technical field of automobile calipers, and particularly relates to a high-strength and high-toughness automobile caliper mold which comprises a casting cavity, a pouring cup is arranged on one side of the casting cavity, a transverse pouring gate is communicated with the pouring cup, vertical pouring gates are communicated with the two ends of the transverse pouring gate, and the transverse pouring gate is communicated with one side of the casting cavity. The cross gate is communicated with one side of the casting cavity, the downsprue is communicated with the other side of the casting cavity, the cross gate is in lap joint with one side of the casting cavity through a first slag-avoiding sheet, the cross gate is in lap joint with the downsprue through a second slag-avoiding sheet, and the cross gate and the downsprue are in lap joint once through the first sheet. And the vertical pouring gate adopts the second sheet for secondary lap joint, so that molten iron slag and part of floating sand from the pouring opening to the sand mold pouring cup can be collected, the purity of mold filling molten iron of the casting is ensured, and the mechanical property and quality of the casting are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of automotive calipers, and particularly relates to a high-strength and high-toughness automotive caliper mold and a production method thereof. Background Art

[0002] The calipers of the automotive braking system are mainly used for frequent braking of automobiles to ensure the running safety of automobiles. Disc brakes are more advanced in technology and lighter in weight. Their heat dissipation performance, braking performance, and adaptability to complex weather and road conditions are more excellent. They are used in both new energy vehicles and traditional vehicles, and are becoming more and more widespread. The national standard grade of the calipers used in the disc brake system is QT550-6. With the rapid development of highway construction, the stability of the automotive braking system has also been correspondingly improved. The production quality control is generally controlled according to a higher grade. Although the strength of the national standard QT600-3 has been improved, its elongation rate is only 3%, which obviously cannot meet the target of the elongation rate ≥ 6% in QT550-6.

[0003] Currently, the calipers of the automotive braking system are generally cast iron parts formed by pouring through a mold. The mainstream production of cast iron parts is synthetic cast iron made from scrap steel, carburant, and return iron. During the pouring process of the existing mold, the slag in the molten iron and the floating slag involved in the molten iron during the pouring process affect the mechanical properties of the internal material of the casting, resulting in sand and slag inside the poured calipers, reducing the mechanical properties and quality of the casting. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a high-strength and high-toughness automotive caliper mold. By using a first thin sheet for one-time lapping of the cross-gate and the sprue, and a second thin sheet for secondary lapping of the vertical gate, it can collect the molten iron slag and part of the floating sand from the pouring port to the sand mold pouring cup, ensuring the purity of the molten iron for filling the casting, thereby solving the problem that the slag in the molten iron and the floating slag involved in the molten iron during the pouring process of the existing mold affect the mechanical properties of the internal material of the casting, resulting in sand and slag inside the poured calipers.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A high-strength and high-toughness automotive caliper mold includes a casting cavity. One side of the casting cavity is provided with a pouring cup. The pouring cup is connected with a cross-gate. Both ends of the cross-gate are connected with vertical gates. The cross-gate is connected with one side of the casting cavity, and the vertical gate is connected with the other side of the casting cavity. The connection between the cross-gate and one side of the casting cavity and the connection between the cross-gate and the vertical gate are both lapped by a first slag-avoiding thin sheet, and the connection between the vertical gate and the other side of the casting cavity is lapped by a second slag-avoiding thin sheet.

[0006] Preferably, the casting cavity includes a main cavity, with a first pouring gate and a second pouring gate connected to both sides of the main cavity respectively. The first pouring gate is connected to the vertical runner through a second slag skimming sheet, and the second pouring gate is connected to the horizontal runner through a first slag skimming sheet.

[0007] Preferably, first risers and second risers are respectively arranged at both ends of the horizontal runner, and a third riser is arranged between the first riser and the second riser. The first riser and the second riser are lapped with the vertical runner through a first slag skimming sheet, and the third riser is lapped with the second pouring gate through a first slag skimming sheet.

[0008] Preferably, 4 casting cavities are arranged in a cross shape on the same horizontal plane, and a sprue is arranged in the middle of the 4 casting cavities. One end of the sprue is lapped with the third riser through a first slag skimming sheet.

[0009] Preferably, a fourth riser and a fifth riser are arranged on the vertical runner, and the fourth riser and the fifth riser are respectively lapped with the first pouring gate on both sides of the main cavity through a second slag skimming sheet.

[0010] Preferably, an empty groove is arranged between the first riser and the third riser on the horizontal runner.

[0011] A production method of a high-strength and high-toughness automotive caliper, including an automotive caliper mold, is composed of the following elemental components by mass percentage: nodulizer: 1% ± 0.05%, C: 3.7 - 3.8%, Mn: 0.35% ± 0.05%, Cu: 0.3% ± 0.05%, Si: 2.5% ± 0.1%, Sn: 0.1 - 0.15%, and the balance is Fe and unavoidable impurities.

[0012] Preferably, the production method includes the following steps: S1: Place scrap steel in an electric furnace to heat up and melt the scrap steel, and tap the molten iron after obtaining it; S2: Use the sandwich spheroidization method to perform sub-packaging spheroidization on the molten iron; S3: Transfer the spheroidized molten iron into a mold for extrusion molding and filling. After the temperature ≤ 500 °C, demold to obtain a caliper casting.

[0013] Preferably, S1 further includes the following steps: Add graphite, ferrosilicon, and silicomanganese to the molten iron in sequence. After mixing and stirring, add silicon carbide for deoxidation within 2 - 3 minutes before tapping, and tap after the components are qualified.

[0014] Preferably, in S3, the spheroidization rate of the caliper casting detected quickly ≥ 80%, the tensile strength of the caliper casting ≥ 550 Mpa, and the elongation rate of the caliper casting ≥ 6%.

[0015] The beneficial effects of the present invention compared with the prior art are as follows: By using the first thin sheet for the first lap joint in the cross-riser and the straight-riser, and the second thin sheet for the second lap joint in the vertical riser, the molten iron slag and part of the floating sand from the pouring gate to the sand mold pouring cup can be collected, ensuring the purity of the molten iron for casting the mold cavity, and improving the mechanical properties and quality of the casting.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description, will become apparent in part from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a front structural front view of a high-strength and high-toughness automotive caliper mold.

[0018] Figure 2 It is a side view of a high-strength and high-toughness automotive caliper mold.

[0019] Figure 3 It is a front structural front view of the back of a high-strength and high-toughness automotive caliper mold.

[0020] In the figure: 1, casting cavity; 11, main cavity; 12, first pouring gate; 13, second pouring gate; 2, pouring cup; 3, cross-riser; 31, first riser; 32, second riser; 33, third riser; 4, vertical riser; 5, first slag-avoiding thin sheet; 6, second slag-avoiding thin sheet; 61, fourth riser; 62, fifth riser; 7, straight-riser; 8, empty groove. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following specifically describes the embodiments of the present invention in detail in conjunction with the drawings and examples. The following examples are used to illustrate the present invention, but cannot be used to limit the scope of the present invention. All other examples obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0022] Combined Figure 1 , Figure 2 and Figure 3 As shown, a high-strength and high-toughness automotive caliper mold includes a casting cavity 1. The shape and size of the casting cavity 1 strictly follow the design requirements of the automotive caliper to ensure that the cast caliper can perfectly match the automotive braking system. The interior of the cavity is finely processed with a smooth surface, which is beneficial to the filling and solidification of the molten metal and reduces the generation of internal defects.

[0023] A pouring cup 2 is provided on one side of the casting cavity 1. The pouring cup 2 is the entrance for the molten metal to enter the mold. The pouring cup 2 ensures that the molten metal can flow into the cross-riser 3 smoothly and quickly, while reducing the splashing and oxidation of the molten metal when it enters the mold.

[0024] A runner cup 2 is connected to a horizontal runner 3. Both ends of the horizontal runner 3 are connected to vertical runners 4. The horizontal runner 3 is connected to one side of the casting cavity 1, and the vertical runner 4 is connected to the other side of the casting cavity 1. The horizontal runner 3 starts from the runner cup 2, spans across the width direction of the mold, and is connected to the vertical runners 4 at both ends. The horizontal runner 3 ensures that the molten metal can flow evenly and stably to all parts of the casting cavity 1. The vertical runner 4 is perpendicularly connected to the horizontal runner 3 and is responsible for guiding the molten metal to the other side of the casting cavity 1. The vertical runner 4 ensures that the molten metal can flow smoothly and unobstructedly into the casting cavity 1, while reducing the eddy current and dead zone during the flow of the molten metal, and improving the density and uniformity of the casting.

[0025] Both the connection between the horizontal runner 3 and one side of the casting cavity 1 and the connection between the horizontal runner 3 and the vertical runner 4 are overlapped by a first slag - avoiding thin sheet 5. The function of the first slag - avoiding thin sheet 5 is to intercept impurities and dross in the molten metal and prevent them from entering the casting cavity 1, thereby ensuring the purity and quality of the casting. The design of the thin sheet takes into account the flow direction and impact force of the molten metal to ensure that while intercepting impurities, it will not cause too much resistance to the flow of the molten metal.

[0026] The connection between the vertical runner 4 and the other side of the casting cavity 1 is overlapped by a second slag - avoiding thin sheet 6. The second slag - avoiding thin sheet 6 also undertakes the task of intercepting impurities and dross. Its design fully considers the connection characteristics between the vertical runner 4 and the casting cavity 1 to ensure that during the flow of the molten metal, it can effectively block impurities from entering the casting cavity 1 while ensuring the smooth flow of the molten metal.

[0027] This high - strength and high - toughness automotive caliper mold can effectively avoid slag, ensuring the uniform flow of molten metal and the effective removal of impurities during the casting process, thereby producing high - quality and high - performance automotive caliper products.

[0028] Combined Figure 1 、 Figure 2 and Figure 3 As shown, the casting cavity 1 includes a main cavity 11. The shape of the main cavity 11 is exactly the same as the final product form of the automotive caliper, including key features such as the caliper body, piston holes, and friction pad contact surfaces. The inner surface of the main cavity 11 is precision - machined using advanced numerical control machining technology to ensure that the dimensional accuracy and surface roughness of the cavity reach the micron - level standard.

[0029] A first pouring port 12 and a second pouring port 13 are respectively connected to both sides of the main cavity 11. The first pouring port 12 is connected to the vertical runner 4 through the second slag - avoiding thin sheet 6, and the second pouring port 13 is connected to the horizontal runner 3 through the first slag - avoiding thin sheet 5.

[0030] Specifically, the first pouring port 12 is not only precisely sized, but also docked with the vertical runner 4, ensuring that the molten metal can flow into the main cavity 11 in the shortest path and at the fastest speed, reducing the heat loss and oxidation risk of the molten metal during the filling process. The edge of the first pouring port 12 is also chamfered to reduce the turbulence and eddy current of the molten metal when it flows in, further reducing the possibility of pores and inclusions in the casting.

[0031] The vertical runner 4 is an important channel connecting the first pouring port 12 and the molten metal source. The vertical runner 4 ensures that the molten metal can maintain a stable flow rate and pressure distribution during the flow process. The addition of the second slag-avoiding sheet 6 further improves the quality of the casting. The first slag-avoiding sheet 5 can effectively intercept and block impurities and scum in the molten metal to prevent them from entering the main cavity 11, thereby ensuring the purity and internal quality of the casting.

[0032] The second pouring port 13 is located on the other side of the main cavity 11, and complements the first pouring port 12 to achieve balanced filling of the main cavity 11 by the molten metal. The second pouring port 13 optimizes its size and position so that the molten metal can flow into the main cavity 11 evenly and slowly, reducing stress concentration and deformation problems caused by uneven filling.

[0033] The runner 3 serves as the main channel connecting the second pouring port 13 with the molten metal source, taking into account the flow characteristics of the molten metal and the need for slag avoidance. The cross-sectional shape and size of the runner 3 are carefully designed to ensure that the molten metal can maintain a stable flow state during the flow process and reduce turbulence and eddy currents. The addition of the first slag avoidance sheet 5 further improves the quality of the casting. The first slag avoidance sheet 5 can effectively filter impurities and slag in the molten metal to prevent it from entering the main cavity 11, thereby ensuring the purity and surface quality of the casting.

[0034] Combination Figure 1 , Figure 2 and Figure 3 As shown, a first riser 31 and a second riser 32 are respectively provided at both ends of the horizontal runner 3, a third riser 33 is provided in the middle of the first riser 31 and the second riser 32, the first riser 31 and the second riser 32 are overlapped with the vertical runner 4 through the first slag avoidance sheet 5, and the third riser 33 is overlapped with the second pouring port 13 through the first slag avoidance sheet 5.

[0035] Specifically, the first riser 31 and the second riser 32 ensure that the molten metal can flow smoothly and evenly into the runner 3. The first riser 31 and the second riser 32 have spacious internal spaces, which are conducive to the rapid filling of the molten metal and provide sufficient molten metal reserves for the subsequent shrinkage feeding process.

[0036] At the connection of the third riser 33 and the cross-riser 3, as well as at the overlapping parts of the first riser 31 and the second riser 32 with the vertical riser 4, the first slag-avoiding thin sheet 5 is used for connection. The first slag-avoiding thin sheet 5 can not only effectively intercept impurities and dross in the molten metal, preventing them from entering the cross-riser 3 and subsequent cavities, but also ensure the sealing and stability of the molten metal during the flow process, reducing the leakage and eddy current phenomena of the molten metal, and improving the density and purity of the casting.

[0037] The third riser 33 is located in the middle position between the first riser 31 and the second riser 32, enabling the molten metal to be more evenly distributed to each area during the filling process, reducing the stress concentration and crack risk caused by uneven flow of the molten metal. The third riser 33 is also overlapped with the second pouring gate 13 through the first slag-avoiding thin sheet 5, ensuring that the molten metal can continuously maintain a pure state during the process of flowing from the third riser 33 into the second pouring gate 13 and further into the main cavity 11, avoiding the influence of impurities on the quality of the casting.

[0038] Combined Figure 1 、 Figure 2 and Figure 3 As shown, there are 4 casting cavities 1 arranged in a cross shape on the same horizontal plane. A vertical riser 7 is provided in the middle of the 4 casting cavities 1. One end of the vertical riser 7 is overlapped with the third riser 33 through the first slag-avoiding thin sheet 5.

[0039] Specifically, in the complex die structure for precision casting of automotive calipers, the layout design of the casting cavities 1 is extremely ingenious. Especially when there are 4 casting cavities 1 arranged in a cross shape on the same horizontal plane, it not only optimizes the space utilization rate, but also greatly improves the casting efficiency and the quality of the casting.

[0040] These 4 casting cavities 1 are like a carefully laid out chessboard, being both independent and closely connected to each other, jointly constituting an efficient and stable casting unit. Each casting cavity 1 strictly follows the design standards of the automotive caliper, from shape to size, all of which have been precisely calculated and repeatedly verified to ensure that the finally cast caliper can perfectly meet the requirements of the automotive braking system. The cross-shaped arrangement enables the molten metal to be more evenly distributed to each cavity during the filling process, reducing the stress concentration and crack risk caused by uneven flow, laying a solid foundation for the high-quality forming of the casting.

[0041] In the center of these 4 casting cavities 1, a vertical riser 7 is cleverly provided. This vertical riser 7 is not only the hub of the molten metal flow, but also the soul of the entire casting system. The vertical riser 7 ensures that the molten metal can flow into each casting cavity 1 at a stable and uniform speed.

[0042] One end of the sprue 7 is seamlessly connected to the third riser 33 through the first slag - avoiding thin sheet 5. The third riser 33 not only undertakes the functions of feeding, exhausting gas, and accommodating impurities, but also provides additional buffer space for the molten metal through its unique design layout. The first slag - avoiding thin sheet 5 can not only efficiently intercept impurities and dross in the molten metal and prevent them from entering the casting cavity 1, but also ensure the sealing and stability of the molten metal during the flowing process, providing a strong guarantee for the high - quality forming of the casting.

[0043] Combined with 1 and Figure 3 As shown, on the vertical runner 4, there are a fourth riser 61 and a fifth riser 62. The fourth riser 61 and the fifth riser 62 are respectively lapped with the first pouring ports 12 on both sides of the main cavity 11 through the second slag - avoiding thin sheet 6.

[0044] Specifically, the vertical runner 4 is like a vertical lifeline running through the entire mold structure, providing a smooth channel for the molten metal from the furnace to the casting cavity 1. Its cross - sectional shape and size are precisely calculated, which not only ensure that the molten metal can flow with sufficient pressure and speed, but also avoid the turbulence and splashing phenomena caused by too fast flow velocity. The inner wall of the vertical runner 4 is specially treated with high smoothness and good wear resistance, effectively reducing the flow resistance of the molten metal and improving the filling efficiency.

[0045] The fourth riser 61 and the fifth riser 62 ensure that the molten metal can be fully buffered and fed during the flowing process. They not only provide additional storage space for the molten metal, but also effectively guide the molten metal to flow into the casting cavity 1 along the predetermined path through their unique structural design.

[0046] The fourth riser 61 and the fifth riser 62 are respectively lapped with the first pouring ports 12 on both sides of the main cavity 11 through the second slag - avoiding thin sheet 6 to achieve efficient lapping.

[0047] Combined with Figure 1 、 Figure 2 and Figure 3 As shown, there is an empty groove 8 between the first riser 31 and the third riser 33 on the horizontal runner 3.

[0048] Specifically, the empty groove 8 set between the first riser 31 and the third riser 33, as a buffer area in the horizontal runner 3, can effectively adjust the flow velocity and pressure distribution of the molten metal. When the molten metal flows from the vertical runner 4 into the horizontal runner 3, it first passes through the buffering and guiding of the first riser 31 and then flows into the empty groove 8. In the empty groove 8, the velocity and pressure of the molten metal are further adjusted so that it can flow into the subsequent third riser 33 and the casting cavity 1 in a more uniform and stable state.

[0049] During the casting process, the temperature change of the molten metal can trigger significant thermal stress. The existence of the empty groove 8 provides an additional cooling and heat dissipation space for the molten metal, which helps to reduce the thermal stress caused by excessive temperature gradient. Through the buffering effect of the empty groove 8, the temperature change of the molten metal during the flow process becomes smoother, thereby reducing the risk of cracks in the casting.

[0050] A large amount of gas is generated during the filling process of the molten metal. If these gases cannot be discharged in time, pore defects will be formed, affecting the quality of the casting. The design of the empty groove 8 provides an additional discharge channel for the gas, which helps the gas to escape smoothly during the filling process of the molten metal, thereby improving the density and purity of the casting.

[0051] Combined Figure 1 and Figure 3 As shown in, a production method of a high-strength and high-toughness automotive caliper includes an automotive caliper mold, which consists of the following elemental components by mass percentage: spheroidizing agent: 1% ± 0.05%, C: 3.7 - 3.8%, Mn: 0.35% ± 0.05%, Cu: 0.3% ± 0.05%, Si: 2.5% ± 0.1%, Sn: 0.1 - 0.15%, and the balance is Fe and unavoidable impurities.

[0052] A production method of a high-strength and high-toughness automotive caliper lies in a carefully designed material formula and a refined manufacturing process. This method first relies on an automotive caliper mold customized for high-performance requirements, which not only needs to have high precision and excellent surface finish, but also needs to be able to withstand the material flow and solidification processes under high temperature and high pressure to ensure the dimensional accuracy and shape stability of the final product.

[0053] In terms of material selection, this automotive caliper uses a strictly proportioned alloy cast iron material, and its unique elemental composition design aims to achieve a perfect balance between strength and toughness. Specifically, this alloy cast iron is carefully formulated from the following elemental components by mass percentage:

[0054] Spheroidizing agent: 1% ± 0.05%. The addition of the spheroidizing agent is crucial for improving the microstructure of cast iron, which can promote the precipitation of graphite in a spherical form rather than the traditional flake form, thereby significantly improving the tensile strength and toughness of the material and reducing the possibility of crack generation.

[0055] Carbon (C): 3.7 - 3.8%. An appropriate carbon content is the basis for ensuring the hardness and wear resistance of the cast iron matrix. At the same time, it works in synergy with the spheroidizing agent to optimize the graphite morphology and improve the comprehensive performance.

[0056] Manganese (Mn): 0.35% ± 0.05%. The manganese element can not only improve the hardenability and enhance the strength of the material, but also further improve the wear resistance and fatigue resistance by forming fine and uniform carbides.

[0057] Copper (Cu): 0.3% ± 0.05%. The addition of copper can refine the grains, improve the toughness and corrosion resistance of the material, especially in high temperature environments, copper can effectively improve the thermal stability of the material.

[0058] Silicon (Si): 2.5% ± 0.1%. Silicon is an important element that promotes graphitization. An appropriate amount of silicon content helps to form evenly distributed spherical graphite while improving the material's resistance to thermal cracking and oxidation resistance.

[0059] Tin (Sn): 0.1-0.15%. As a trace element, tin can improve the cutting performance of cast iron, reduce the phenomenon of work hardening, and also play a positive role in improving the corrosion resistance and high temperature strength of the material.

[0060] The balance is Fe and inevitable impurities: Iron, as a matrix element, ensures the basic mechanical properties of the material, while strict control of impurity content is the key to ensuring material purity and performance stability.

[0061] The entire production process requires advanced smelting technology, precise component control, strict heat treatment process and precision machining to ensure that each car caliper can meet or even exceed the performance standards required by the design, providing a solid guarantee for the safe driving of the car.

[0062] Combination Figure 1 and Figure 3 As shown, the production method includes the following steps: S1, placing scrap steel in an electric furnace to heat and heat up, melting the scrap steel, and tapping the molten iron after obtaining molten iron; S2, using a sandwich spheroidizing method to transfer the molten iron to spheroidize; S3, transferring the spheroidized molten iron into a mold for extrusion molding, and after filling the mold, demolding after the temperature is ≤500°C to obtain a caliper casting.

[0063] Specifically, the production of a high-strength, high-toughness automotive caliper requires a rigorous and sophisticated process, with each step designed to optimize material properties and ensure the superior quality of the final product. The following are the detailed steps of the production method:

[0064] S1. Raw material pretreatment and melting stage: Select high-quality scrap steel as the main raw material. The scrap steel needs to be strictly screened to remove inclusions and non-metallic impurities to ensure the purity and consistency of the raw materials. Put the pretreated scrap steel into an energy-efficient electric furnace. By precisely controlling the power and heating rate of the electric furnace, the scrap steel is gradually heated to a completely molten state. During this process, the high-temperature environment of the electric furnace is used to promote the uniform distribution of various elements in the scrap steel. At the same time, advanced on-line detection technologies are adopted to monitor the temperature and chemical composition of the molten iron in real time to ensure the stability and controllability of the melting process. When the molten iron reaches the preset temperature and the chemical composition meets the formula requirements, the tapping operation is carried out. During the tapping process, a special tapping hole and diversion trough are used to reduce the contact between the molten iron and air, avoid oxidation and gas absorption, and ensure the purity of the molten iron.

[0065] S2. Spheroidizing treatment stage: For the characteristics of molten iron, the advanced sandwich spheroidizing method is adopted for spheroidizing treatment. In this method, a layer of spheroidizing agent is pre-laid at the bottom of the ladle, followed by a layer of inoculant, and finally the molten iron is poured in to form a "sandwich" structure. During the pouring of the molten iron, the spheroidizing agent and inoculant react quickly, promoting the precipitation of carbon elements in the molten iron in the form of spherical graphite, while refining the grains and improving the comprehensive mechanical properties of the material. During the spheroidizing treatment process, advanced equipment such as thermal imagers and spectrometers are used to monitor the changes in the temperature and chemical composition of the molten iron in real time to ensure that the spheroidizing reaction is sufficient and uniform. By adjusting the addition amount and addition timing of the spheroidizing agent and inoculant, the spheroidizing effect is precisely controlled to achieve the best material properties.

[0066] S3. Casting and forming stage: Select high-precision and high-abrasion-resistant die materials. Through precision machining and heat treatment, ensure the dimensional accuracy and surface quality of the die. The die is internally designed with reasonable cooling water channels to control the cooling rate of the casting, reduce thermal stress and deformation. Quickly transfer the spheroidized molten iron into the preheated die. Through high-pressure extrusion and rapid filling technology, the molten iron fills the die cavity in a very short time to form a dense casting structure. During this process, the filling speed and pressure are precisely controlled to avoid casting defects such as pores and shrinkage porosity. After the casting naturally cools to a certain temperature (≤500 °C) in the die, the demolding operation is carried out. During the demolding process, special demolding agents and demolding tools are used to ensure that the surface of the casting is smooth and undamaged. After demolding, the casting needs to be immediately cleaned and inspected to remove surface flash, burrs and other defects to prepare for subsequent processing.

[0067] Through the careful operation and strict control of the above steps, the finally obtained automotive caliper casting not only has excellent properties of high strength and high toughness, but also has good dimensional accuracy and surface quality, and can meet the strict requirements of the automotive industry for safety, reliability and durability.

[0068] Combined with Figure 1 and Figure 3As shown, S1 also includes the following steps: successively add graphite, ferrosilicon, and silicomanganese into the molten iron. After mixing and stirring, add silicon carbide for deoxidation within 2 - 3 minutes before tapping. After the composition is qualified, tap the molten iron.

[0069] Specifically, in the high-quality production process of automotive calipers, the raw material pretreatment and melting in the S1 stage are key links in laying the foundation for the product. The specific operation steps are as follows: Select high-quality scrap steel that has undergone strict screening as the main raw material, remove non-metallic impurities such as dirt, sand, and paint mixed in it, and use magnetic separation equipment to further separate light metal impurities such as rust and iron filings that may be mixed in the scrap steel to ensure the purity and consistency of the raw materials and provide a high-quality foundation for subsequent melting. Put the pretreated scrap steel into an energy-efficient electric furnace, and use an advanced intelligent control system to precisely adjust the power of the electric furnace. According to factors such as the material, shape, and size of the scrap steel, reasonably set the heating rate to gradually heat the scrap steel to a completely molten state. During the melting process, continuously monitor the temperature of the molten iron, and use a spectral analyzer to online detect the chemical composition of the molten iron to ensure that the melting process is stable and controllable and the composition of the molten iron is uniform.

[0070] When the temperature of the molten iron reaches the appropriate alloy addition temperature (generally 1450 - 1500 °C), first slowly add a certain amount of graphite to the molten iron. The addition of graphite helps to improve the fluidity of the molten iron and creates good conditions for the uniform distribution of subsequent elements. During the addition process, use a stirring device to continuously stir the molten iron so that the graphite can be quickly dispersed in the molten iron and prevent local enrichment.

[0071] After the graphite is fully dispersed, successively add ferrosilicon and silicomanganese. Ferrosilicon and silicomanganese, as important alloying elements, can significantly improve the strength, hardness, and wear resistance of the molten iron. When adding, also use the method of slowly adding and continuously stirring to ensure that ferrosilicon and silicomanganese fully react with the molten iron and are evenly distributed in the molten iron. At the same time, closely monitor the temperature and composition changes of the molten iron, and adjust the addition amount and stirring speed in a timely manner according to the real-time detection data.

[0072] Within 2 - 3 minutes before tapping, accurately weigh the required amount of silicon carbide and quickly add it to the molten iron. Silicon carbide plays a key deoxidation role at this stage, can effectively remove the dissolved oxygen in the molten iron, reduce the formation of oxides in the casting, and improve the purity and mechanical properties of the casting. After adding silicon carbide, continue to stir the molten iron to make silicon carbide fully react with the oxygen in the molten iron to ensure that the deoxidation effect reaches the best.

[0073] After adding silicon carbide for deoxidation, use advanced online composition detection equipment, such as a direct-reading spectrometer, etc., to quickly and accurately detect the chemical composition of the molten iron. The detection items include main elements such as carbon, silicon, manganese, phosphorus, sulfur, and impurity elements that may exist to ensure that the content of each component strictly meets the requirements of the preset high-strength and high-toughness formula.

[0074] After the molten iron composition is detected to be qualified, the tapping operation is carried out. During the tapping process, a special tapping hole and a diversion groove are used. The inside of the diversion groove is treated with a special coating to reduce the friction and adhesion between the molten iron and the diversion groove, ensure the smooth flow of the molten iron, and avoid oxidation and gas absorption at the same time, guaranteeing the purity and fluidity of the molten iron. The molten iron after tapping is immediately transferred to the next stage of the spheroidizing treatment process.

[0075] Through the above-mentioned refined operations in the S1 stage, from raw material preparation, melting control to alloy element addition and deoxidation treatment, each link is carefully designed and strictly controlled, laying a solid foundation for producing high-quality and high-performance automotive caliper castings, ensuring that the final product can meet the strict requirements of the automotive industry for safety, reliability, and durability.

[0076] Combined Figure 1 and Figure 3 As shown, the spheroidization rate of the caliper casting in S3 is ≥80%, the tensile strength of the caliper casting is ≥550 Mpa, and the elongation of the caliper casting is ≥6%.

[0077] Specifically, in the S3 stage of the automotive caliper production process, that is, the quality inspection link after casting and forming, there are extremely strict requirements for key performance indicators such as the spheroidization rate, tensile strength, and elongation of the caliper casting, and it is necessary to ensure that the spheroidization rate is ≥80%, the tensile strength is ≥550 MPa, and the elongation is ≥6%.

[0078] According to relevant standards (such as GB / T 228.1-2010 "Metallic materials - Tensile testing - Part 1: Method of test at room temperature"), standard tensile specimens are machined from the caliper casting and tensile tests are carried out on an electronic universal testing machine. Record the load-displacement curve of the specimen during the tensile process, and calculate the tensile strength based on the curve data. The calculation formula for tensile strength is: σb = Fb / S0, where σb is the tensile strength, Fb is the maximum load before the specimen breaks, and S0 is the original cross-sectional area of the specimen.

[0079] Non-destructive testing methods such as ultrasonic testing and X-ray testing are used to detect the internal defects of the caliper casting. Internal defects such as shrinkage cavities, shrinkage porosity, and cracks will reduce the tensile strength of the casting. Through non-destructive testing, these defects can be detected in time and the quality of the casting can be evaluated.

[0080] Precisely control the contents of main elements such as carbon, silicon, manganese, phosphorus, and sulfur in the molten iron, as well as the addition amounts of trace alloy elements. A reasonable chemical composition can ensure that the casting has good mechanical properties and improve the tensile strength. For example, appropriately increasing the carbon equivalent can increase the strength and hardness of the casting, but too high a carbon equivalent will cause coarse graphite and reduce toughness.

[0081] Formulate a reasonable heat treatment process, such as normalizing, quenching + tempering, etc., to improve its tensile strength by changing the organizational structure of the casting. During the heat treatment process, strictly control parameters such as heating temperature, holding time, and cooling rate to ensure the best heat treatment effect.

[0082] Strengthen the quality control during the casting process to reduce the generation of casting defects such as pores, slag inclusions, and sand holes. These defects will become stress concentration points and reduce the tensile strength of the casting. Through measures such as optimizing the casting process, improving the quality of the mold, and strengthening the pouring operation, effectively control casting defects.

[0083] While detecting the tensile strength through a tensile test, record the elongation of the specimen during the tensile process by a tensile testing machine, and calculate the elongation rate according to the formula ε=(L - L0) / L0×100%, where ε is the elongation rate, L is the gauge length of the specimen after fracture, and L0 is the original gauge length of the specimen.

[0084] Use microscopic analysis methods such as scanning electron microscopy (SEM) to observe the microscopic morphology and organizational structure of the tensile fracture of the caliper casting. By analyzing the characteristics such as the size, distribution, and morphology of the dimples on the fracture surface, the plastic deformation ability and elongation rate of the casting can be evaluated.

[0085] Through the above detailed detection and strict safeguard measures for spheroidization rate, tensile strength, and elongation rate, it can be ensured that the caliper castings produced in the S3 stage meet the high-performance requirements of spheroidization rate ≥ 80%, tensile strength ≥ 550 MPa, and elongation rate ≥ 6%, providing a strong guarantee for the production of high-quality and highly reliable automotive calipers.

[0086] This is a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. An automotive caliper mold with high strength and high toughness, including a casting cavity. On one side of the casting cavity (1), there is a pouring cup (2). A cross-riser (3) is connected to the pouring cup (2). Both ends of the cross-riser (3) are connected to vertical risers (4). The cross-riser (3) is connected to one side of the casting cavity (1), and the vertical riser (4) is connected to the other side of the casting cavity (1). Both the connection between the cross-riser (3) and one side of the casting cavity (1) and the connection between the cross-riser (3) and the vertical riser (4) are overlapped by a first thin sheet (5), and the connection between the vertical riser (4) and the other side of the casting cavity (1) is overlapped by a second thin sheet (6).

2. The high-strength and high-toughness automotive caliper mold according to any one of claims 1, characterized in that The casting cavity (1) includes a main cavity (11). On both sides of the main cavity (11), there are a first pouring port (12) and a second pouring port (13) respectively. The first pouring port (12) is connected to the vertical riser (4) through the second thin sheet (6), and the second pouring port (13) is connected to the cross-riser (3) through the first thin sheet (5).

3. The high-strength and high-toughness automotive caliper mold according to claim 2, characterized in that, On both ends of the cross-riser (3), there are a first riser (31) and a second riser (32) respectively. Between the first riser (31) and the second riser (32), there is a third riser (33). The first riser (31) and the second riser (32) are overlapped with the vertical riser (4) through the first thin sheet (5), and the third riser (33) is overlapped with the second pouring port (13) through the first thin sheet (5).

4. The high-strength and high-toughness automotive caliper mold according to claim 3, characterized in that, Four casting cavities (1) are arranged in a "field" shape on the same horizontal plane. A connecting runner (7) is arranged in the middle of the four casting cavities (1). One end of the connecting runner (7) is overlapped with the third riser (33) through the first thin sheet (5).

5. The high-strength and high-toughness automotive caliper mold according to claim 4, characterized in that, On the vertical riser (4), there are a fourth riser (61) and a fifth riser (62). The fourth riser (61) and the fifth riser (62) are overlapped with the first pouring ports (12) on both sides of the main cavity (11) through the second thin sheet (6).

6. The high-strength and high-toughness automotive caliper mold according to claim 5, characterized in that An empty groove (8) is arranged between the first riser (31) and the third riser (33) on the cross-riser (3).

7. A production method of an automotive caliper mold with high strength and high toughness, including the automotive caliper mold according to any one of 1-6, characterized in that, It is composed of the following elements by mass percentage: spheroidizing agent: 1% ± 0.05%, C: 3.7 - 3.8%, Mn: 0.35% ± 0.05%, Cu: 0.3% ± 0.05%, Si: 2.5% ± 0.1%, Sn: 0.1 - 0.15%, and the balance is Fe and inevitable impurities.

8. The production method of a high-strength and high-toughness automotive caliper according to claim 7, characterized in that, The production method includes the following steps: S1: Place scrap steel in an electric furnace to heat up and melt the scrap steel. After obtaining molten iron, tap the iron. S2: Use the sandwich spheroidizing method to perform sub-packaging spheroidization on the molten iron. S3: Transfer the spheroidized molten iron into the automotive caliper mold for extrusion molding and filling. After the temperature ≤ 500 °C, demold to obtain caliper castings.

9. The production method of a high-strength and high-toughness automotive caliper according to claim 8, characterized in that S1 also includes the following steps: Add graphite, ferrosilicon, and silicomanganese to the molten iron in sequence. After mixing and stirring, add silicon carbide for deoxidation within 2 - 3 minutes before tapping. After the composition is qualified, tap the furnace.

10. The production method of a high-strength and high-toughness automotive caliper according to claim 9, characterized in that, In S3, the spheroidization rate of the caliper castings detected quickly ≥ 80%, the tensile strength of the caliper castings ≥ 550 Mpa, and the elongation rate of the caliper castings ≥ 6%.

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