CN120587431B - A die-casting mold - Google Patents

Abstract

The invention relates to a die casting die which comprises a die body, wherein the die body is provided with a profile surface, the profile surface is provided with a flow guide network, the flow guide network comprises a plurality of first groove bodies and second groove bodies which are arranged in a crossing mode, the width of each first groove body is 0.1-0.5mm, the depth of each first groove body is 50 mu m-0.2mm, the width of each second groove body is 0.08-0.3mm, the depth of each second groove body is 0.02-0.15mm, and the included angle between any first groove body and any second groove body is 30-95 degrees. Through the cross network of first cell body and second cell body, constitute directional water conservancy diversion route at the profile face, main tank guide nitrogen gas covers large tracts of land region fast, and the branch groove is with the air current introduction microcell, and die casting die can show the surface area that promotes the profile face when nitriding process, promotes the diffusion efficiency of nitriding gas, makes nitriding gas evenly diffuse along the profile face surface, promotes nitrogen atom absorption and diffusion, and then promotes the degree of depth and the homogeneity that nitrogen gas permeated.

Description

A die-casting mold

Technical Field

The present invention relates to the technical field of die casting, in particular to a die casting die.

Background Art

Molds are key process equipment used in industrial manufacturing to form various parts. By applying pressure and temperature to materials like metal and plastic, they form products of specific shapes within the mold cavity. Their core structure comprises a fixed mold cavity, which determines the product's external shape, and a dynamic mold core, which forms the internal structure. These are supplemented by a gating system, ejection mechanism, and guide components to achieve efficient production. Mold performance directly impacts product quality and production efficiency, especially under high-temperature and high-pressure conditions such as die-casting and injection molding. Surface hardening treatments are crucial, as mold surfaces must withstand molten metal erosion, molten material adhesion, and cyclical thermal stresses.

Nitriding in mold manufacturing involves infiltrating nitrogen atoms into the steel surface under high temperature, forming a modified layer composed of high-hardness nitrides. This significantly improves the mold's wear resistance, corrosion resistance, and anti-sticking properties. This process primarily involves gas nitriding and ion nitriding. Gas nitriding decomposes ammonia to produce active nitrogen atoms, which diffuse into the mold steel at high temperatures. Ion nitriding utilizes plasma bombardment to rapidly inject nitrogen ions into the surface, resulting in a faster and more environmentally friendly penetration rate.

However, as product structures become increasingly complex, molds often incorporate complex contours such as deep holes, thin walls, multi-curvature surfaces, and insert combinations. This makes it difficult to control the uniformity of the nitriding layer, leading to large variations in layer thickness and significant fluctuations in the quality of the nitriding layer. While existing manufacturing processes have been optimized through methods such as staged heating and localized airflow adjustments, they still cannot address the inherent constraints of geometric features on nitrogen atom transport. Homogenization technology has become a key shortcoming in high-end mold manufacturing.

Summary of the Invention

Based on this, it is necessary to provide a die-casting mold that can effectively improve the quality of the nitriding permeation layer of the die-casting and increase the service life of the die-casting mold.

The technical solution is as follows: a die-casting mold, comprising: a mold body, the mold body being provided with a contour surface, and the contour surface being provided with a flow guide network, wherein the flow guide network comprises a plurality of cross-arranged first trough bodies and second trough bodies, the width of the first trough body being 0.1-0.5mm, and the depth being 50μm-0.2mm; the width of the second trough body being 0.08-0.3mm, and the depth being 0.02-0.15mm, and the angle between any first trough body and the second trough body being 30°-95°.

In one embodiment, continuous arc transition structures are provided at the corners of all parting surfaces of the mold body, the radius R of the arc transition structure is ≥ 0.8 mm, and adjacent arcs are connected by smooth curves.

In one embodiment, the groove walls of the first groove body and the second groove body are provided with a micro-nano structure layer, and the micro-nano structure layer includes a plurality of spaced-apart protrusions, the diameter of the protrusions is 50-200 nm, and the height of the protrusions is 20-100 nm.

In one embodiment, the mold body is provided with an air vent, the contour surface is provided with a blind hole, the air vent is communicated with the bottom wall of the blind hole, and the air vent runs through the mold body.

In one embodiment, the air vent includes a main channel and branch channels that are interconnected, one end of the main channel is connected to the bottom wall of the blind hole, the diameter of the main channel is 2-3 mm, the diameter of the branch channel is 1-1.5 mm, the branch channel is connected to the side wall of the mold body, and a transition structure is provided at the connection between the main channel and the branch channel, and the opening angle of the transition structure is 120°-160°.

In one embodiment, the inner wall of the air pore is provided with a first catalytic coating, the first catalytic coating comprises at least one element of Cr, Al, and Ti, and the coating thickness is 5-15 μm.

In one embodiment, the wall thickness ratio of any two points on the contour surface is ≤1.5.

In one embodiment, the mold body is further provided with a cooling water channel, and the ratio of the shortest distance between any position of the cooling water channel and the contour surface to the wall thickness at that position is in the range of 0.2 to 0.4.

In one embodiment, the inner wall of the cooling water channel is provided with a second catalytic coating, the thickness of the second catalytic coating is 5-15 μm, the surface porosity is ≤5%, and the thermal conductivity is ≥30 W/m·K.

In one embodiment, the die-casting mold further includes an insert, and the mold body further includes a dovetail groove. The insert and the mold body are plugged into the dovetail groove, and the angle between the hypotenuse and the bottom edge of the dovetail groove is 55°-65°.

In one embodiment, a sealing ring groove is provided on the contact surface between the insert and the mold body, and the sealing ring groove is used to install a sealing member.

In one embodiment, the surface roughness Ra of the insert is 0.8-1.6 μm.

In one embodiment, a micro-groove array is provided on the surface of the insert, wherein the width of the micro-groove is 0.01-0.03 mm, the depth is 50 μm-0.2 mm, and the spacing between adjacent micro-grooves is 0.05-0.15 mm.

The die-casting mold, through the intersecting network of the first and second troughs, constructs a directional flow path on the contour surface. The main trough guides nitrogen gas to quickly cover a large area, while the branch troughs direct the gas flow into micro-regions, forming a "main road + capillary" gas distribution system. The trough dimensions ensure that gas neither stagnates nor leaks, and the Venturi effect in fluid mechanics is utilized to accelerate the diffusion of nitriding gas. In this way, the die-casting mold can significantly increase the surface area of the contour surface during the nitriding process. At the same time, the first and second troughs are arranged at a specific angle to optimize gas turbulence and prevent the formation of gas vortices at right angles. This can improve the diffusion efficiency of the nitriding gas, allowing it to diffuse evenly along the contour surface, promoting the adsorption and diffusion of nitrogen atoms, and thereby increasing the depth and uniformity of nitrogen penetration. In addition, by limiting the width, angle and depth range of the first trough body and the second trough body, the overall strength and contour surface shape of the die-casting mold can be avoided from being affected, and the nitrogen coverage rate can be further improved, thereby improving the diffusion uniformity of nitrogen atoms, ensuring the diffusion of nitriding gas while reducing the entry of melt, thereby ensuring the integrity of the contour surface and improving the die-casting accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

FIG1 is a schematic structural diagram of a die-casting mold according to an embodiment;

FIG2 is a schematic structural diagram of the die-casting mold according to an embodiment from another perspective.

FIG3 is a schematic structural diagram of a cooling water channel of a die-casting mold according to an embodiment;

FIG4 is a schematic structural diagram of the cooling water channel of the die-casting mold according to one embodiment from another perspective.

Description of reference numerals:

100. Die-casting mold; 110. Mold body; 111. Contour surface; 112. First trough body; 113. Second trough body; 114. Arc transition structure; 120. Blind hole; 121. Air vent; 130. Cooling water channel.

DETAILED DESCRIPTION

To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

Please refer to Figure 1, which shows a schematic structural diagram of a die-casting mold 100 described in an embodiment of the present invention. An embodiment of the present invention provides a die-casting mold 100, comprising: a mold body 110. The mold body 110 is provided with a contour surface 111, and the contour surface 111 is provided with a flow guide network, wherein the flow guide network includes a plurality of cross-arranged first grooves 112 and second grooves 113, wherein the width of the first groove 112 is 0.1-0.5mm and the depth is 50μm-0.2mm; the width of the second groove 113 is 0.08-0.3mm and the depth is 0.02-0.15mm, and the angle between any first groove 112 and the second groove 113 is 30°-95°.

The mold body 110 may be a mold cavity, a mold core, or other mold parts.

The die-casting mold 100, through the intersecting network of first and second troughs 112, 113, constructs a directional flow path on the contour surface 111. The main trough guides nitrogen gas to quickly cover a large area, while the branch troughs direct the gas flow into micro-regions, forming a "main channel + capillary" gas distribution system. The trough dimensions ensure that gas neither stagnates nor leaks, utilizing the Venturi effect in fluid mechanics to accelerate the diffusion of nitriding gas. Thus, the die-casting mold 100 can significantly increase the surface area of the contour surface 111 during the nitriding process. Furthermore, the intersecting arrangement of the first and second troughs 112, 113 at a specific angle optimizes gas turbulence, prevents the formation of gas vortices at right angles, and improves the diffusion efficiency of the nitriding gas, ensuring uniform diffusion of the nitriding gas along the surface of the contour surface 111. This promotes the adsorption and diffusion of nitrogen atoms, thereby increasing the depth and uniformity of nitrogen penetration. In addition, by limiting the width, angle and depth range of the first trough body 112 and the second trough body 113, the overall strength of the die-casting mold 100 and the shape of the contour surface 111 are avoided from being affected, and the nitrogen coverage rate can be further improved, thereby improving the diffusion uniformity of nitrogen atoms, ensuring the diffusion of nitriding gas while reducing the entry of melt, thereby ensuring the integrity of the contour surface 111 and improving the die-casting accuracy.

It should be noted that the width of the first groove body 112 and the second groove body 113 is the maximum width of the space in the groove. Similarly, the depth of the first groove body 112 and the second groove body 113 is the shortest distance between the lowest point in the groove and the groove opening.

Optionally, the cross-sectional shapes of the first trough body 112 and the second trough body 113 can be arc-shaped, rectangular, triangular, wavy, trapezoidal, or other irregular shapes. Specifically, in this embodiment, the cross-sectional shapes of the first trough body 112 and the second trough body 113 are arc-shaped. This can further improve the diffusion efficiency of ammonia during nitriding and enhance the uniformity of the nitriding process. This embodiment only provides one cross-sectional shape option for the first trough body 112 and the second trough body 113, but is not limited thereto.

In one embodiment, the surface roughness Ra of the contour surface 111 is in the range of 0.7-1.9 μm. This provides sufficient nitrogen atom adsorption sites to increase the penetration depth of the nitriding gas, while also preventing excessive roughness that could affect the surface profile quality of the casting, avoid obvious scratches or mold sticking marks, and facilitate smooth demolding.

In one embodiment, a continuous arc transition structure 114 is provided at the corners of all parting surfaces of the mold body 110, the radius R of the arc of the arc transition structure 114 is ≥ 0.8 mm, and adjacent arcs are connected by smooth curves. The corners of the parting surface are stress concentration areas when the mold is subjected to force. Right-angled or sharp-angled structures are prone to cracks due to high-frequency die-casting loads, and the arc transition can evenly disperse the stress by increasing the radius of curvature at the corners to avoid local stress overload; the adjacent arcs are connected by smooth curves to eliminate the secondary stress concentration points caused by the traditional broken line transition and form a continuous and smooth force conduction path. By designing an arc transition with a radius greater than or equal to 0.8 mm, it is helpful to eliminate the tip effect of the traditional right angle and reduce the excessive aggregation of nitrogen atoms at the corners. Smooth curved connections avoid stress concentration, resulting in a more uniform temperature field and nitrogen potential distribution on the mold surface. Nitrogen atoms diffuse along the tangent direction of the arc, making the diffusion path more uniform. This reduces or even prevents the shedding of the nitride layer on contour surface 111 and uneven thickness, suppressing local over-thickness or over-thinness. This significantly improves the mold's resistance to fatigue cracking and extends its service life. Furthermore, the arc transition structure 114 reduces frictional resistance during mold closing, preventing wear-induced gaps on the parting surface, thereby reducing flash defects in die-cast parts and improving the dimensional accuracy of the castings.

It should be noted that “continuous arcs” refer to all corners, including the main parting surface and the side parting surface, which need to be provided with arc transition structures 114 .

In one embodiment, the groove walls of the first groove body 112 and the second groove body 113 are provided with a micro-nano structure layer. The micro-nano structure layer includes a plurality of spaced protrusions, the diameter of the protrusions is 50-200nm; the height of the protrusions is 20-100nm. For example, the protrusions may be conical, semicircular, spherical, truncated cone or other shapes. The nanoscale protrusions increase the specific surface area of the groove wall, provide more adsorption sites for the nitriding gas, increase the adsorption rate of nitrogen atoms, promote the initial attachment of nitrogen atoms to the groove wall surface, prolong the residence time, increase the penetration depth of nitrogen atoms, optimize the surface energy, promote the wetting and spreading of nitrogen atoms, and improve the penetration uniformity. The height difference of the protrusions forms a nanoscale concave-convex structure, which can change the flow state of the gas in the groove, make it easier for the nitriding gas to penetrate into the microscopic gaps in the groove wall, and enhance the contact efficiency between the gas and the metal matrix. In this way, the micro-nanostructure layer is conducive to greatly improving the adsorption rate and diffusion depth of nitrogen atoms during the nitriding process, so that the surface hardness and wear resistance of the groove area are significantly enhanced; at the same time, the size control of the micro-nanostructure can avoid the groove being blocked due to excessive protrusions, and can ensure the transmission efficiency of the nitriding gas to the guide network, taking into account the balance between the nitriding effect and the melt flow resistance, while avoiding melt residue.

Optionally, the protrusions may be formed by plasma etching, laser nanomachining, or the like.

In one embodiment, referring to FIG. 1 , the mold body 110 is provided with a vent hole 121. The contour surface 111 is provided with a blind hole 120, which communicates with the bottom wall of the blind hole 120 and extends through the mold body 110. Specifically, as shown in FIG. 1 , there are multiple blind holes 120 of the same or different shapes, with each blind hole 120 corresponding to at least one vent hole 121. During the die-casting process, when molten metal is injected into the mold cavity, the blind holes 120 collect trapped gas near the contour surface 111 and discharge the gas out of the mold through the vent holes 121, thereby preventing the formation of gas pore defects on the casting surface. The structure in which the vent holes 121 communicate with the bottom wall of the blind hole 120 and penetrate the bottom wall of the blind hole 120 helps avoid deep cavity gas shielding, allowing the nitriding gas to directly reach the bottom of the blind hole 120 through the vent holes 121, thereby resolving the gas stagnation problem caused by the small opening and large depth of conventional blind holes 120. The diameter of the vent hole 121 matches the size of the blind hole 120, avoiding the creation of additional flow resistance. This allows gas to be discharged directly without passing through the mold cavity, shortening the exhaust path. This effectively discharges residual gas within the mold cavity, improving the surface quality and internal density of the die-cast part. The blind hole 120 is concealed within the contour surface 111, preventing the risk of molten metal infiltration caused by direct connection between the vent hole 121 and the mold cavity, ensuring the long-term stable operation of the exhaust system.

Furthermore, the air vent 121 includes a main channel and branch channels that are interconnected. One end of the main channel is connected to the bottom wall of the blind hole 120, and the branch channel is connected to the side wall of the mold body 110. The diameter of the main channel is 2-3mm, and the diameter of the branch channel is 1-1.5mm. A transition structure is provided at the connection between the main channel and the branch channel, and the opening angle of the transition structure is 120°-160°. The branch channel is connected to the side wall of the mold body 110. The main channel serves as the main gas channel, providing sufficient gas flow cross-sectional area, and the branch channels are radially distributed. The gas partial pressure is separated to gradually reduce the pressure of the high-pressure gas, ensuring the stability of the nitrogen potential at the outlet of the branch hole and expanding the exhaust coverage. The large-angle opening of the transition structure makes the transition between the main channel and the branch channel smooth, which is conducive to reducing the flow resistance of the gas when entering the branch channel from the main channel, avoiding the generation of vortexes, and ensuring uniform and rapid discharge of the gas. Through the graded channel design, efficient exhaust of different areas of the contour surface 111 is achieved, which is particularly suitable for gas exhaust from complex cavities. Furthermore, the diameter ratio of the main channel and the branch channel is ≈2:1, which can achieve better results in gas dynamics. Too large or too small will affect the pressure distribution effect. Therefore, a reasonable aperture ratio and transition angle can ensure the exhaust efficiency while preventing blockage problems caused by excessively thin branch channels, thereby improving the reliability of the exhaust system.

In one embodiment, the inner wall of the vent 121 is provided with a first catalytic coating, which includes at least one element selected from Cr, Al, and Ti, and has a thickness of 5-15 μm. Specifically, the oxides of Cr, Al, and Ti have catalytic activity, which can reduce the activation energy of the nitriding reaction and help accelerate the chemical reaction between nitrogen atoms and the mold body 110. At the same time, the first catalytic coating can isolate the high-temperature nitriding gas from direct contact with the mold body 110, inhibiting oxidation of the mold body 110 and protecting the inner wall of the vent 121. This, in turn, significantly increases the permeation rate of nitrogen atoms during the nitriding process and improves the uniformity of the surface hardness in the area surrounding the vent 121. Furthermore, the corrosion resistance of the coating prevents the vent 121 from failing due to long-term exposure to high-temperature gas, thereby extending the maintenance cycle of the die-casting mold 100.

In one embodiment, the wall thickness ratio of any two points on the contour surface 111 is ≤1.5. Excessive wall thickness differences can lead to uneven cooling rates in different areas of the mold during the die-casting process. Thick walls form thermal nodes due to slow heat dissipation, generating thermal stress, while thin walls cause shrinkage stress due to rapid cooling. The superposition of the two can easily cause mold deformation or cracking. By controlling the wall thickness ratio within a reasonable range, the overall temperature field distribution of the mold can be made more uniform, avoiding local overheating or overcooling, and reducing thermal stress concentration. On the one hand, it can improve the structural strength and dimensional stability of the mold, avoid cavity deformation caused by wall thickness differences, and thus ensure the dimensional accuracy of the die-casting part. On the other hand, the uniform temperature field can reduce the fluctuation of the nitrogen atomic diffusion coefficient, suppress the layer depth difference caused by the temperature gradient, reduce the thickness difference of the nitride layer at the wall thickness mutation point, and improve the uniformity of the nitride layer. At the same time, the uniform wall thickness design of the contour surface 111 can simplify the cooling system layout and improve cooling efficiency.

Furthermore, the wall thickness ratio between any two points on the contour surface 111 of the mold body 110 is 0.8-1.2, which can further ensure uniform wall thickness, thereby improving the uniformity of the nitride layer thickness by controlling the uniformity of the temperature field.

In one embodiment, referring to Figures 2 and 3, Figure 2 shows a schematic structural diagram of the die-casting mold 100 according to one embodiment of the present invention from another perspective, and Figure 3 shows a schematic structural diagram of the cooling channels of the die-casting mold 100 according to one embodiment of the present invention. Figure 4 shows a schematic structural diagram of the cooling channels of the die-casting mold 100 according to one embodiment of the present invention from another perspective. The mold body 110 further includes cooling channels 130, and the ratio of the shortest distance between any position of the cooling channels 130 and the contour surface 111 to the wall thickness at that position ranges from 0.2 to 0.4. For example, the cooling channels 130 are disposed within the mold body 110, close to the contour surface 111, and the shortest distance between the cooling channels 130 and the contour surface 111 is less than the shortest distance between the cooling channels 130 and the fixed surface. Specifically, referring to Figures 2, 3, and 4, there are multiple cooling channels 130, and the multiple cooling channels 130 are interconnected. This distance can not only ensure that there is a sufficient heat conduction path between the cooling medium and the contour surface 111, avoiding the weakening of the contour surface 111 due to the close distance, but also prevent the cooling efficiency from decreasing due to the long distance; the uniform distance setting can make each area of the contour surface 111 heated evenly, avoiding local overheating, ensuring that the mold body 110 maintains a stable temperature field during the high-speed die-casting process, and preventing defects such as shrinkage and deformation of the casting caused by temperature fluctuations; a reasonable cooling distance takes into account both mold strength and heat dissipation efficiency, thereby improving the stability of die-casting production.

In one embodiment, the inner wall of the cooling water channel 130 is provided with a second catalytic coating. The thickness of the second catalytic coating is 5-15 μm, the surface porosity of the second catalytic coating is ≤5%, and the thermal conductivity of the second catalytic coating is ≥30 W/m・K. The high thermal conductivity property of the coating can accelerate the heat exchange between the cooling medium and the mold body 110, improve the heat dissipation efficiency, accelerate the uniform distribution of heat, increase the nitrogen potential in the area around the cooling water channel 130, and avoid the problem of insufficient penetration. The low porosity design can prevent impurities in the cooling medium, such as scale and ions, from penetrating into the coating, avoiding peeling or corrosion of the coating; the coating material can resist electrochemical corrosion of the cooling medium, extend the service life of the water channel, significantly improve the thermal conductivity of the cooling system, make the mold temperature control more precise, and reduce defects in castings caused by uneven cooling; the corrosion resistance of the coating can reduce the maintenance cost of the water channel and avoid production interruptions caused by water channel blockage.

Optionally, the second catalytic coating may be made of metal nitride coating, such as TiAlN, CrN, AlCrN; or metal carbide coating, such as WC-Co, TiC; or metal-based composite coating, such as Ni-Cr alloy, Cu-Al _alloy , or ceramic coating, such as _Al2O3 , _ZrO2 .

Preferably, the second catalytic coating is made of titanium aluminum nitride. This offers high thermal conductivity, excellent hardness, high-temperature resistance, wear resistance, and corrosion resistance, extending the service life of the mold body 110. Furthermore, TiAlN coatings deposited via PVD (physical vapor deposition) or CVD (chemical vapor deposition) processes offer strong bonding strength with the mold steel substrate (e.g., H13, SKD61), reducing the risk of coating spalling. This makes them particularly suitable for areas like the cooling channel 130 that are subject to alternating thermal stresses. This embodiment provides only one specific material option for the second catalytic coating, but is not intended to be limiting.

In one embodiment, the die-casting mold 100 further includes an insert. The mold body 110 further defines a dovetail groove, through which the insert is plugged and mated with the mold body 110. The angle between the bevel and the bottom of the dovetail groove is 55°-65°. This design of the insert allows for independent secondary nitriding of vulnerable areas such as the gate and core head, increasing the depth of the localized permeation layer and preventing nitrided layer shedding. The angle between the bevel and the bottom of the dovetail groove balances the ease of installation and structural stability of the insert. When the angle is less than 55°, the insert is difficult to remove. When the angle is greater than 65°, the lateral forces generated during the die-casting process can easily cause the insert to fall out. This angle range allows the insert to produce a self-locking effect under die-casting loads while facilitating mechanical assembly and disassembly, facilitating rapid assembly and disassembly of the insert and the mold body 110 and facilitating replacement and maintenance of vulnerable parts. The stable mating structure can withstand the impact forces of high-pressure die-casting and prevent dimensional deviations in the casting caused by insert displacement.

In one embodiment, the contact surface between the insert and the mold body 110 is provided with a sealing ring groove for mounting a seal. In the high-temperature, high-pressure die-casting environment, the sealing ring elastically deforms to fill the contact surface gap of the sealing ring groove, forming a dynamic seal. This blocks the leakage of nitriding gas from the contact surface between the insert and the substrate, while also preventing molten metal from penetrating the mating surface between the insert and the body. This design maintains elasticity at high temperatures, ensuring sealing performance. This helps completely eliminate problems such as flash and mold sticking caused by molten metal leakage, thereby improving the surface quality of the casting. Furthermore, the replaceable design of the sealing ring reduces mold maintenance costs and avoids seal failure due to contact surface wear.

Specifically, the sealing member is a high-temperature resistant sealing ring. Furthermore, the Shore hardness of the sealing ring is 70-80A. This is conducive to balancing sealing performance and aging resistance.

In one embodiment, the surface roughness Ra of the insert is 0.8-1.6 μm. This roughness range can provide sufficient surface microscopic concave-convex structures to form a micro-adsorption surface, provide sufficient nitrogen atom adsorption sites, and increase the depth of the nitride layer on the surface of the insert, thereby increasing the bonding strength between the surface nitride layer and the matrix of the insert and reducing the risk of peeling. It is also beneficial to enhance the mechanical bite between the molten metal and the surface of the insert, preventing the insert from moving with the casting during demolding, and avoiding the increase in metal flow resistance and scratches on the casting surface caused by excessive roughness values, which is beneficial to balancing the demolding performance and the surface quality of the casting. When the roughness is moderate, the casting is demolded smoothly, and there are no obvious scratches or mold sticking marks on the surface; at the same time, this roughness range is easy to achieve through grinding, polishing and other processes, taking into account both processing efficiency and precision requirements.

In one embodiment, the surface of the insert is provided with an array of microgrooves, each with a width of 0.01-0.03 mm and a depth of 50 μm-0.2 mm, with a spacing of 0.05-0.15 mm between adjacent microgrooves. In this way, the microgrooves can form a flow-guiding network on the surface of the insert, guiding the nitriding gas to diffuse directionally along the surface of the insert, improving the uniformity of the thickness of the nitriding layer on the surface of the insert and increasing the penetration depth of the edge area. Furthermore, the microgrooves can store release agent or gas during the die-casting process, forming a lubricating layer or air cushion, reducing the direct contact area between the molten metal and the insert surface and lowering frictional resistance. Furthermore, the dimensional design of the microgrooves (small width and depth) prevents molten metal from penetrating into the grooves and solidifying, which could lead to groove failure. This can significantly reduce the sticking phenomenon between the casting and the insert, improving demolding efficiency. The microgroove array can also promote the uniform filling of the mold cavity by changing the flow path of the molten metal, improving the local filling capacity of the casting and reducing defects such as cold shuts and flow marks.

The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims (11)

1. A die-casting mold, characterized in that the die-casting mold comprises: A mold body, wherein the mold body is provided with a contour surface, and the contour surface is provided with a flow guide network, and continuous arc transition structures are provided at the corners of all parting surfaces of the mold body, the radius of the arc of the arc transition structure R ≥ 0.8 mm, and adjacent arcs are connected by smooth curves, wherein the flow guide network includes a plurality of cross-arranged first trough bodies and second trough bodies, the width of the first trough body is 0.1-0.5 mm, and the depth is 50 μm-0.2 mm; the width of the second trough body is 0.08-0.3 mm, and the depth is 0.02-0.15 mm, and the angle between any first trough body and the second trough body is 30°-95°, and the groove walls of the first trough body and the second trough body are provided with a micro-nano structure layer, and the micro-nano structure layer includes a plurality of spaced-apart protrusions, the diameter of the protrusions is 50-200 nm; the height of the protrusions is 20-100 nm. 2. The die-casting mold according to claim 1, wherein the mold body is provided with an air vent, the contour surface is provided with a blind hole, the air vent is communicated with the bottom wall of the blind hole, and the air vent runs through the mold body. 3. The die-casting mold according to claim 2 is characterized in that: the air vent includes a main channel and branch channels that are interconnected, one end of the main channel is connected to the bottom wall of the blind hole, the diameter of the main channel is 2-3 mm, the diameter of the branch channel is 1-1.5 mm, the branch channel is connected to the side wall of the mold body, and a transition structure is provided at the connection between the main channel and the branch channel, and the opening angle of the transition structure is 120°-160°. 4. The die-casting mold according to claim 2, wherein the inner wall of the air vent is provided with a first catalytic coating, the first catalytic coating comprises at least one element of Cr, Al, and Ti, and the coating thickness is 5-15 μm. 5 . The die-casting mold according to claim 1 , wherein the wall thickness ratio of any two points on the contour surface is ≤1.5. 6. The die-casting mold according to claim 1, wherein the mold body is further provided with a cooling water channel, and the ratio of the shortest distance between any position of the cooling water channel and the contour surface to the wall thickness at that position is in the range of 0.2 to 0.4. 7. The die-casting mold according to claim 6, characterized in that the inner wall of the cooling water channel is provided with a second catalytic coating, the thickness of the second catalytic coating is 5-15 μm, the surface porosity is ≤5%, and the thermal conductivity is ≥30 W/m·K. 8. The die-casting mold according to any one of claims 1 to 7, characterized in that: the die-casting mold further comprises an insert, the mold body further comprises a dovetail groove, the insert and the mold body are plug-fitted into the dovetail groove, and the angle between the hypotenuse and the bottom edge of the dovetail groove is 55°-65°. 9 . The die-casting mold according to claim 8 , wherein a sealing ring groove is provided on the contact surface between the insert and the mold body, and the sealing ring groove is used for installing a sealing member. 10 . The die-casting mold according to claim 8 , wherein the surface roughness Ra of the insert is 0.8-1.6 μm. 11. The die-casting mold according to claim 10, wherein a micro-groove array is formed on the surface of the insert, the micro-groove has a width of 0.01-0.03 mm, a depth of 50 μm-0.2 mm, and a spacing between adjacent micro-grooves of 0.05-0.15 mm.