Die-casting die structure with cooling water channel

Abstract

The utility model discloses a die-casting die structure with a cooling water channel. The die-casting die structure comprises a die structure body and the cooling water channel. The mold structure body is formed by implanting the cooling water channel into the powder base body and then molding through a hot isostatic pressing process; the cooling water channel is made of stainless steel, a compact bonding layer is formed at the junction of the cooling water channel and the powder base body through a hot isostatic pressing process, and the grain structure of the bonding layer comprises M23C6 type carbide and / or M6C type carbide. The gap between the mold structure body and the cooling water channel made of the stainless steel is eliminated through the hot isostatic pressing technology, the heat dissipation effect is good after forming, rusting is not likely to happen, the service life is long, and the later maintenance cost is low.

Description

Technical Field

[0001] This application relates to the field of die-casting mold components technology, specifically a die-casting mold structure with cooling water channels. Background Technology

[0002] Currently, the sprue bushing is typically installed between the pressure chamber and the runner cone to connect them. During casting, the molten metal in the pressure chamber enters the mold through the sprue bushing and runner cone. The speed and temperature of the molten metal passing through the sprue bushing have a significant impact on the quality of the final die-cast product. Therefore, cooling channels are usually installed inside the sprue bushing, through which a circulating coolant at a specific temperature and flow rate is introduced to regulate the temperature of the molten metal. The sprue bushing is a key component in die-casting molds that guides the molten metal into the mold cavity and must meet the following core requirements:

[0003] High temperature resistance: Must withstand the high temperature of molten aluminum (typically 670-700℃);

[0004] Thermal fatigue resistance: Frequent thermal cycling can easily lead to material cracking;

[0005] High wear resistance: High-speed scouring by molten metal can easily cause wear;

[0006] Thermal stability: Dimensional accuracy must be maintained at high temperatures;

[0007] Machining performance: Facilitates precision machining and heat treatment.

[0008] In existing technologies, the cooling of hot runner bushings is a crucial issue that cannot be ignored in mold making. During mold production, sufficient cooling and control of the mold temperature at the gate are necessary; improving cooling efficiency and surface quality at the gate is also crucial, while simultaneously shortening the cooling time at the hot runner. Due to the design requirements of the hot runner bushing gate, the larger the contact area between the cooling water channels within the bushing and the product, the better the cooling effect; however, this also results in less space for the cooling water channel design. Furthermore, the temperature at the gate is often the highest in die casting, thus placing high demands on the strength and temperature control of the parts.

[0009] Many sprue bushings on the market are limited by their manufacturing processes, and can only be produced using traditional machining methods, which are complex and costly. Furthermore, during subsequent use, the sprue bushing expands due to heat, and the welded joints are prone to cracking, leading to leakage in the cooling water channels. For example, in the die-casting industry, the current cooling system mostly relies on drilling holes at multiple locations (allowing only straight inlet and outlet), connecting them in series through the holes, and then plugging the outside to achieve water circulation. This not only results in uneven cooling but also insufficient overall stability. This phenomenon is particularly noticeable in thinner-walled areas such as the sprue area and the gate area of ​​the sprue bushing. The internal angled holes, misalignments, and sharp corners that cause stress cracking will greatly reduce the lifespan of the sprue bushing.

[0010] When using 3D printing, the sprue bushing is prone to rust and corrosion, and the internal flow channel walls are full of burrs and are not smooth. The lifespan of the sprue bushing is extremely short, which cannot meet the needs of modern high-precision molds and will directly affect the quality and pass rate of the product.

[0011] Therefore, how to improve the cooling water channels in the existing die-casting mold structure to overcome the above-mentioned shortcomings is a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0012] One objective of this application is to provide a die-casting mold structure with cooling water channels that has good cooling effect, long service life, and low maintenance cost.

[0013] To achieve the above objectives, the technical solution adopted in this application is as follows: a die-casting mold structure with cooling water channels, including a mold structure body and cooling water channels; the mold structure body is formed by hot isostatic pressing after the cooling water channels are implanted into a powder matrix; the material of the cooling water channels is stainless steel, and a dense bonding layer is formed at the interface between the cooling water channels and the powder matrix by the hot isostatic pressing process, wherein the grain structure of the bonding layer includes M23C6 type carbides and / or M6C type carbides.

[0014] Preferably, the material of the cooling water channel is 304L stainless steel. Furthermore, the horizontal dimension of the cooling water channel is 10.5%-18% larger than the final product design drawing, and the vertical dimension of the cooling water channel is 10%-18% larger than the final product design drawing.

[0015] Preferably, the powder matrix is ​​E23A hot work die steel powder. Further, the horizontal dimension of the die structure body is 9%-18% larger than the final product design drawing, and the vertical dimension of the die structure body is 10%-18% larger than the final product design drawing.

[0016] Preferably, the cooling water channel has a circular cross-section.

[0017] Preferably, the mold structure body is a sprue sleeve.

[0018] Preferably, the cooling water channel includes a first connecting section, a second connecting section, and an intermediate section; the intermediate section is integrally connected between the first connecting section and the second connecting section, and the intermediate section is a spiral structure around the central axis of the sprue sleeve; one end of the first connecting section that is off from the intermediate section and one end of the second connecting section that is off from the intermediate section both extend to the outside of the sprue sleeve.

[0019] Preferably, the cooling water channel includes a first connecting section, a second connecting section, and an intermediate section; the intermediate section is integrally connected between the first connecting section and the second connecting section, and the intermediate section is a double helix structure around the central axis of the sprue sleeve; one end of the first connecting section that is off from the intermediate section and one end of the second connecting section that is off from the intermediate section both extend to the outside of the sprue sleeve.

[0020] Preferably, the first connecting segment and the second connecting segment are both located at the same end of the double helix structure.

[0021] Preferably, the first connecting segment and the second connecting segment are located on the inlet side near the sprue sleeve.

[0022] Compared with the prior art, the beneficial effects of this application are as follows: (1) The mold structure body of this application is formed by hot isostatic pressing of powder matrix. The stability of powder material improves the service life of parts, realizes the improvement of die casting production capacity, and saves mold replacement cost. Compared with traditional machining, it reduces energy consumption, improves material utilization, and has a certain environmental protection effect.

[0023] (2) Because the cooling water channels are embedded in the powder matrix, and through hot isostatic pressing, a dense bonding layer is formed at the interface between the powder matrix and the stainless steel cooling water channels, and the grain structure of the bonding layer includes M 23 C6 type carbide and / or M6C type carbide. The dense bonding layer eliminates the gap between the mold structure body and the cooling water channel, resulting in good cooling effect. The gap between the mold structure body and the cooling water channel does not easily cause rusting, thus significantly extending its service life. Compared with traditional machining methods, there are no misalignments or sharp corners. The internal stainless steel water channel is smooth and clean, with rounded corners, which reduces the risk of stress cracking. Moreover, compared with 3D printing technology, the inner wall of the cooling water channel in this application does not have the problem of burrs after printing.

[0024] (3) Improve cooling performance and shorten production cycle through water channel design: By adopting a water channel shape that cannot be achieved by traditional processing (arranged in a spiral inside the sprue sleeve), the effective cooling water channel length inside the sprue sleeve is extended by more than 3 times. Moreover, the cooling water channel has no sharp corner structure, the water flow is smooth, and it can get closer to the heat concentration area to achieve a more efficient cooling effect and effectively shorten the cooling time of the material cake.

[0025] (4) Easy to maintain and repair. The overall cooling water circuit is made of a single piece of stainless steel pipe or welded from multiple stainless steel pipes. All corners are rounded, eliminating the problem of dirt clogging the water circuit in traditional gate sleeve water circuits. This helps reduce the risk of water circuit blockage.

[0026] (5) With only two inlet and outlet ports, there are no locations for plugging or other similar issues, which can significantly reduce the risk of casting defects caused by water seepage from the sprue sleeve, improve production stability, and help customers save a lot of costs. Attached Figure Description

[0027] Figure 1 Microscopic image of the junction between the mold structure body and the cooling water channel provided in this application.

[0028] Figure 2 The cell structure diagram of the M23C6 type carbide provided in this application.

[0029] Figure 3 The cell structure of the M6C type carbide provided in this application.

[0030] Figure 4 A perspective view of the gate bushing provided in this application.

[0031] Figure 5 Provided for this application Figure 4 A 3D diagram of the central cooling water circuit.

[0032] Figure 6 Provided for this application Figure 4 A sectional view of the middle gate bushing.

[0033] In the diagram: 1. Mold structure body; 2. Cooling water channel; 21. First connecting section; 22. Second connecting section; 23. Intermediate section. Detailed Implementation

[0034] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0035] In the description of this application, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this application.

[0036] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0037] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0038] Reference Figures 1 to 3 One embodiment of this application provides a die-casting mold structure with a cooling water channel 2, including a mold structure body 1 and a cooling water channel 2; the mold structure body 1 is formed by hot isostatic pressing after the cooling water channel 2 is implanted into a powder matrix; the material of the cooling water channel 2 is stainless steel, and a dense bonding layer is formed at the interface between the cooling water channel 2 and the powder matrix by hot isostatic pressing; the grain structure of the bonding layer includes M23C6 type carbide and / or M6C type carbide.

[0039] Through multiple experiments, it was preliminarily verified that the diameter of the stainless steel cooling water channel 2 did not significantly collapse during hot pressing. Overall, the stainless steel material and the powder matrix formed a dense metallurgical bond. The M23C6 type carbide at the bond was the main carbide in the powder matrix. The carbon content in the powder matrix was higher than that in the stainless steel, while the chromium content was lower, and the molybdenum content was higher. During hot isostatic pressing and subsequent cooling, the main process involved the interdiffusion of these three elements.

[0040] Grain structure: The carbide structure is dominated by M23C6 and M6C, with M23C6 being the most predominant. This structure is a complex face-centered cubic structure, with 116 atoms per unit cell, including 96 metal atoms and 24 carbon atoms. Under high temperature and pressure conditions, Cr in the stainless steel and Mo in the powder matrix partially replace Cr in M23C6. M6C carbides also have a face-centered cubic structure, with a lattice constant similar to M23C6. Due to the concentration gradient, some Mo in the powder matrix forms in the diffusion layer. The presence of Ni in the stainless steel also increases the precipitation tendency in M6C carbides, but because its content is lower than Cr, the number of M6C carbides is less than that of M23C6. The complex face-centered cubic carbides formed at the interface between the powder matrix and stainless steel through elemental diffusion result in better bonding.

[0041] The mold structure body 1 of this application is formed from a powder matrix using a hot isostatic pressing (HIP) process. The stability of the powder material improves the service life of the parts, enhances die-casting production capacity, and reduces mold replacement costs. Furthermore, because the cooling water channels 2 are embedded in the powder matrix, and the HIP process creates a dense bonding layer at the interface between the powder matrix and the stainless steel cooling water channels 2, the grain structure of which includes M... 23 C6 type carbide and / or M6C type carbide. The dense bonding layer eliminates the gap between the mold structure body 1 and the cooling water channel 2, resulting in good cooling effect. This eliminates the problem of easy rusting between the mold structure body 1 and the cooling water channel 2 (because the mold structure body 1 does not come into contact with the cooling water, the cooling water flows through the cooling water channel 2, so the mold structure body 1 does not come into contact with water and therefore will not rust), thus significantly extending its service life. Secondly, because of the good bonding effect, the stainless steel cooling water channel 2 completely isolates the water from contact with the mold structure body 1, thereby protecting the body.

[0042] To achieve the same level of corrosion resistance as the stainless steel tube embedded in this product, existing 3D printing technology requires the use of stainless steel powder. However, stainless steel powder cannot be used for printing such mold structures (such as sprue sleeves) for the following two main reasons:

[0043] 1. The types of stainless steel that can be used in 3D printing are limited, and the price of these metal powders is also very expensive. For example, 316L series stainless steel powder can be used for 3D printing, but the volatile elements (such as Cr and Mn) may partially evaporate under high-temperature laser treatment, changing the material composition and affecting corrosion resistance and mechanical properties. In addition, stainless steel has a low absorption rate for common SLM lasers, requiring relatively stringent process conditions. Furthermore, 316L is expensive, and the sprue bushing, as a consumable part, needs to be replaced regularly, which is costly.

[0044] 2. The sprue bushing is a key component in die casting molds that guides molten metal into the mold cavity. It needs to withstand the high temperature of molten aluminum or zinc (usually about 670-700℃). Frequent thermal cycling can easily cause the material to crack. Therefore, it needs to have good thermal conductivity and high yield strength and resistance to deformation, which are characteristics that stainless steel does not possess.

[0045] In some embodiments of this application, the material of the cooling water channel 2 is 304L stainless steel.

[0046] In some embodiments of this application, the powder matrix is ​​E23A hot work die steel powder.

[0047] This application employs a near-net-shape forming process using HIP (hot isostatic pressing). First, the mold structure body 1 and cooling water channel 2 are scaled up proportionally according to their respective shrinkage rates in different directions based on the finished product dimensions (the shrinkage rates of the cooling water channels embedded in the mold structure body are different in the horizontal and vertical directions). Then, a sleeve with added machining allowance is used for metal powder canning and welding followed by hot isostatic pressing.

[0048] Because the E23A powder shrinks differently in the horizontal, vertical and horizontal directions, the horizontal dimension of the mold structure body 1 is 9%-18% larger than the final product design drawing, and the vertical dimension of the mold structure body 1 is 10%-18% larger than the final product design drawing.

[0049] Because the cooling water channels of 304 stainless steel contract differently in the horizontal, vertical and horizontal directions, the horizontal dimension of cooling water channel 2 is 10.5%-18% larger than the final finished product design drawing, and the vertical dimension of cooling water channel 2 is 10%-18% larger than the final finished product design drawing.

[0050] In some embodiments of this application, the cooling water channel 2 has a circular cross-section. The circular structure of the cooling water channel 2 facilitates shaping and bending.

[0051] This application does not limit the specific process of hot isostatic pressing; the following is only one specific process for reference:

[0052] For example, hot work die steel powder is first filled into the casing and then inserted into cooling water channel 2. The mixture is then vibrated until the powder no longer collapses. During hot vacuuming, the heating temperature is 650℃. The water-cooled pipe assembly, after being filled with powder, undergoes hot isostatic pressing. During hot isostatic pressing, a three-stage heat preservation process and a phased cooling process are performed.

[0053] The first stage involves pressurizing the furnace to 20-35 MPa using a hot isostatic pressing system, followed by heating to 750-900℃ at a rate of 10℃ / min, while simultaneously pressurizing to 120-145 MPa and maintaining the pressure for 3-4 hours.

[0054] The second stage involves simultaneously increasing the temperature and pressure to 1030-1150℃ and 140-170MPa, and holding at that temperature for 0.5-4 hours.

[0055] The third stage involves further heating to 1150-1190℃, pressurizing to 170-188MPa, and holding at that temperature for 0.5-4 hours.

[0056] Heating and pressurization are carried out simultaneously.

[0057] The specific process of staged cooling is as follows: the furnace is cooled to 650-780℃ and held for 1.5-3 hours, and then cooled to the furnace outlet temperature at a cooling rate of 0.9℃ / min.

[0058] It should be understood that this application does not limit the specific structure of the mold structure body 1 and the cooling water channel 2. The following only provides a specific structure for reference, see Embodiment 1 for details.

[0059] Example 1

[0060] Reference Figures 4-6 In this embodiment, the mold structure body 1 is the sprue bushing. The aforementioned novel water-cooling structure primarily addresses the vulnerable sprue bushing portion of the injection chamber. This sprue bushing is highly susceptible to damage under its own weight, operational impact, and the erosive action of high-temperature molten metal. This novel water-cooling structure provides constant-temperature cooling to the outer wall of the injection chamber, which is subjected to prolonged exposure to high-temperature molten metal, reducing expansion and deformation caused by temperature increases. The injection chamber of this novel water-cooling structure includes cooling pipes connected to an inlet water pipe and a return water pipe. The arrangement of these cooling pipes allows the coolant to circulate within them. This circulation effectively suppresses cracking and deformation of the sprue bushing portion, as well as preventing aluminum shavings from getting trapped between the punch and the injection chamber, which can lead to punch seizure. This improves the thermal stability and overall strength of the injection chamber, extends its service life, increases product efficiency, and reduces the company's economic costs.

[0061] In this embodiment, the cooling water channel 2 includes a first connecting section 21, a second connecting section 22, and an intermediate section 23. The intermediate section 23 is integrally connected between the first connecting section 21 and the second connecting section 22, and the intermediate section 23 is a spiral structure around the central axis of the sprue sleeve. The ends of the first connecting section 21 and the second connecting section 22 that are off-center from the intermediate section 23 both extend to the outside of the sprue sleeve. By modifying the cooling water channel 2 into a spiral structure, unlike other water channel structures, the impact of uneven shrinkage is reduced, and it is convenient to measure and collect shrinkage data later to serve subsequent manufacturing. It also facilitates the calculation and verification of the hot isostatic pressing shrinkage rate. Furthermore, the spiral structure can increase the contact area between the cooling water channel 2 and the part, ensuring the effectiveness of the cooling water channel 2 while facilitating later maintenance. In addition, the purpose of this embodiment is to serve the hot isostatic pressing technology. During the powder loading process, a sieving effect occurs between the powder matrix, forming a cone shape. Using a spiral cooling water channel 2 has less impact on powder loading and vibration.

[0062] It is understandable that the intermediate section 23 can also be a double-helix structure around the central axis of the sprue bushing. A dual-loop (double-helix) temperature-controlled gradient cooling module is adopted: the spiral cooling channel connected by the water inlet pipe achieves uniform axial temperature field uniformity of the sprue bushing through a conformal water channel design; the three-dimensional curved cooling channel maintains an equidistant gap with the outer wall of the sprue bushing to ensure balanced temperature control. To facilitate the connection of the cooling medium, the first connecting section 21 and the second connecting section 22 are both located at the same end of the double-helix structure. Furthermore, since the inlet side of the sprue bushing faces away from the mold cavity, placing the first connecting section 21 and the second connecting section 22 near the inlet side of the sprue bushing makes it easier for them to connect to the cooling medium.

[0063] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A die casting mold structure with a cooling water path, comprising a mold structure body and a cooling water path; characterized by: The mold structure body is formed by implanting the cooling water channel into a powder base through a hot isostatic pressing process; The material of the cooling water path is stainless steel, and the junction of the cooling water path and the powder matrix forms a dense bonding layer through the hot isostatic pressing process, the grain structure of the bonding layer includes M 23 C6 type carbide and / or M6C type carbide.

2. The die casting mold structure with a cooling water path according to claim 1, wherein The powder base is E23A hot work die steel powder.

3. The die casting mold structure with a cooling water path according to claim 2, wherein The horizontal dimension of the mold structure body is 9%-18% larger than the final product design drawing, and the vertical dimension of the mold structure body is 10%-18% larger than the final product design drawing.

4. The die casting mold structure with a cooling water path according to claim 1, wherein The material of the cooling water channel is 304L stainless steel. The horizontal dimension of the cooling water channel is 10.5%-18% larger than the final product design drawing, and the vertical dimension of the cooling water channel is 10%-18% larger than the final product design drawing.

5. The die casting mold structure with a cooling water path according to claim 1, wherein The cross section of the cooling water channel is a circular structure.

6. A die casting mold structure with a cooling water path according to any one of claims 1 to 5, wherein The mold structure body is a sprue bushing.

7. The die casting mold structure with a cooling water path according to claim 6, wherein The cooling water channel comprises a first connecting section, a second connecting section, and an intermediate section; the intermediate section is integrally connected between the first connecting section and the second connecting section, and the intermediate section is a spiral structure around the central axis of the sprue bushing; one end of the first connecting section deviating from the intermediate section and one end of the second connecting section deviating from the intermediate section both penetrate to the outside of the sprue bushing.

8. The die casting mold structure with a cooling water path according to claim 6, wherein The cooling water channel comprises a first connecting section, a second connecting section, and an intermediate section; the intermediate section is integrally connected between the first connecting section and the second connecting section, and the intermediate section is a double spiral structure around the central axis of the sprue bushing; one end of the first connecting section deviating from the intermediate section and one end of the second connecting section deviating from the intermediate section both penetrate to the outside of the sprue bushing.

9. The die casting mold structure with a cooling water path according to claim 8, wherein The first connecting section and the second connecting section are located at the same end of the double spiral structure.

10. The die casting mold structure with a cooling water path according to claim 9, wherein The first connecting section and the second connecting section are located close to the inlet side of the sprue bushing.

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