Injection head of laser cladding copper alloy die-casting machine

Abstract

The utility model discloses a laser cladding copper alloy die-casting machine injection head, which comprises an integrated body, is made of a high-temperature wear-resistant base material, and comprises a cylindrical working part, a push rod connecting part, a plunger head and a copper alloy cladding layer. A containing cavity for storing a cooling liquid inner container is formed in the cylindrical working part, and a spiral groove structure is arranged on the surface of the peripheral wall of the cylindrical working part. The push rod connecting part comprises a cylindrical connecting part and a prismatic connecting part; the cylindrical connecting part is connected with one end part of the cylindrical working part, and a spiral groove structure is arranged on the surface of the peripheral wall of the cylindrical connecting part; wherein the push rod connecting part is provided with a connecting cavity, and the connecting cavity penetrates through the cylindrical connecting part and the prismatic connecting part and is provided with a threaded connecting part used for being connected with the push rod; the plunger head is arranged at the end, away from the prismatic connecting part, of the cylindrical working part, and an annular fillet transition zone is arranged on the edge, connected with the cylindrical working part, of the plunger head. And the copper alloy cladding layer uniformly covers the spiral groove structures of the cylindrical working part and the cylindrical connecting part through a laser cladding process.

Description

Technical Field

[0001] This utility model relates to the field of die-casting equipment technology, specifically to a laser-clad copper alloy die-casting machine injection head. Background Technology

[0002] In the field of die casting equipment technology, the injection head, as one of the core components of a die casting machine, is mainly used to push molten metal to fill the mold cavity. Its performance directly affects the quality of die-cast products and production efficiency. Traditional die casting machine injection heads have the following shortcomings in practical applications:

[0003] Firstly, the injection head operates in a high-temperature, high-pressure, and high-friction environment for extended periods. The substrate is prone to deformation or even breakage due to high-temperature softening or mechanical stress, leading to the failure of the main body. At the same time, although coatings (such as plating or thermal spraying) can improve surface hardness, the bonding strength between the coating and the substrate is insufficient. Under thermal stress, frictional wear, or molten metal erosion, the coating is prone to peeling off, exposing the substrate directly to the molten metal and accelerating the wear of the injection head.

[0004] Secondly, the injection head generates a lot of heat when it comes into contact with molten metal during operation. If heat dissipation is not timely, the surface temperature may become too high, leading to problems such as material softening and coating performance degradation, thus shortening the service life.

[0005] Third, as a component that directly contacts the molten metal, the plunger head is prone to stress concentration at the connection with the working part due to abrupt changes in geometry. Under high-frequency injection impact, the coating is prone to cracking, and the substrate may also fail due to fatigue damage.

[0006] Fourth, the connection structure between the push rod and the injection head is not stable enough. It is prone to relative rotation during high-pressure transmission, which affects the accuracy of the injection action and leads to fluctuations in the quality of die-cast products.

[0007] Therefore, there is an urgent need to develop an injection head structure that has higher reliability and longer service life under high temperature, high pressure and high friction environments. Utility Model Content

[0008] In order to overcome the shortcomings of the existing technology, the purpose of this utility model is to provide a laser-clad copper alloy die-casting machine injection head, which solves the technical problems of existing die-casting machine injection heads under high temperature, high pressure and high friction conditions, such as easy softening and deformation of the substrate, insufficient coating bonding strength and easy peeling, low heat dissipation efficiency, stress concentration at the plunger head connection and poor stability of the push rod connection.

[0009] To solve the above problems, the technical solution adopted by this utility model is as follows:

[0010] A laser-clad copper alloy die-casting machine injection head, with an integral body made of a high-temperature wear-resistant substrate, comprising:

[0011] The cylindrical working part has an internal cavity for storing coolant, and its outer peripheral wall surface has a spiral groove structure.

[0012] The push rod connecting part includes a cylindrical connecting part and a prismatic connecting part; the cylindrical connecting part is connected to one end of the cylindrical working part, and its outer peripheral wall surface is provided with a spiral groove structure; wherein, the push rod connecting part has a connecting cavity, the connecting cavity passes through the cylindrical connecting part and the prismatic connecting part, and has a threaded connecting part for connecting the push rod;

[0013] The plunger head is located at the end of the cylindrical working part away from the prismatic connecting part, and the edge where it connects with the cylindrical working part is provided with an annular rounded transition zone;

[0014] A copper alloy cladding layer is uniformly applied to the spiral groove structure of the cylindrical working part and the cylindrical connecting part using a laser cladding process.

[0015] Preferably, the high-temperature wear-resistant substrate is any one of ductile iron, 42CrMo alloy steel, or H13 hot work die steel.

[0016] Preferably, the cladding thickness of the copper alloy cladding layer is 1.0-3.0 mm.

[0017] Preferably, the copper alloy cladding layer extends toward the plunger head and completely covers the annular rounded transition zone.

[0018] Preferably, the copper alloy cladding layer at the annular rounded corner transition zone is locally thickened to form an annular reinforcing zone.

[0019] Preferably, the spiral groove structure is a continuous single-head or multi-head spiral groove;

[0020] The spiral groove has a depth of 0.2-0.4 mm, a groove width of 0.3-0.8 mm, and a ridge spacing of 0.5-1.5 mm between adjacent spiral grooves.

[0021] Preferably, the cross-sectional shape of the spiral groove is V-shaped or U-shaped with a rounded bottom, and the radius of the bottom fillet R is ≥ 0.1 mm; the spiral angle of the spiral groove is 30° to 60° and is evenly distributed on the outer peripheral wall surface of the cylindrical working part and the cylindrical connecting part.

[0022] Preferably, the end face of the plunger head is a flat surface or a slightly convex curved surface, and the radius R of the rounded corner transition zone is 0.5–1.0 mm.

[0023] Preferably, the connecting cavity forms an annular retaining edge at one end port facing the receiving cavity and at the upper edge of the threaded connection portion.

[0024] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0025] (1) Improve the structural stability under high temperature and high pressure: adopt an integrated body design and select high temperature and wear-resistant base materials such as ductile iron, 42CrMo alloy steel or H13 hot work die steel to ensure that the injection head has sufficient strength and heat resistance under high temperature and high pressure conditions, and avoid body failure problems such as deformation and fracture caused by high temperature softening or mechanical stress.

[0026] (2) Enhance the bonding strength and wear resistance of the cladding layer: By setting a spiral groove structure on the outer peripheral wall of the cylindrical working part and the cylindrical connecting part (with optimized parameters such as depth 0.2-0.4mm and groove width 0.3-0.8mm), the contact area between the substrate and the copper alloy cladding layer is increased, forming a "biting" mechanical lock, so that the cladding layer and the substrate can achieve metallurgical bonding. The bonding strength is significantly better than that of traditional plating or thermal spraying, significantly improving the bonding strength (shear resistance) between the cladding layer and the substrate. At the same time, the copper alloy (such as Cu-Ni-Cr system or Cu-Al-Fe system) itself has excellent wear resistance and high temperature corrosion resistance, which can directly contact the molten metal and reduce friction loss, avoid the cladding layer from falling off due to wear or corrosion, and extend the protection cycle.

[0027] (3) Optimize heat dissipation efficiency: The cylindrical working part has a cavity for installing a coolant tank. The coolant circulates and absorbs the heat generated by the contact between the injection head and the molten metal. Combined with the high thermal conductivity of the copper alloy cladding layer (quickly transfers heat to the coolant), the surface temperature is effectively reduced, preventing material softening or cladding layer performance degradation due to overheating, and extending service life.

[0028] (4) Relieve stress concentration and improve fatigue resistance: The edge connecting the plunger head and the working part is provided with an annular rounded transition zone (rounded radius 0.5-1.0mm), and the area is completely covered by the copper alloy cladding layer (local thickening forms an annular reinforcing zone) to disperse the stress concentration under high frequency injection impact; the toughness of the copper alloy can absorb some impact energy, reducing the risk of cladding layer cracking and substrate fatigue damage.

[0029] (5) Improve the stability of push rod connection: The push rod connection adopts a combination structure of cylindrical and prismatic shapes (prismatic shape prevents relative rotation), and annular retaining edges are set at the connection cavity port and threaded connection to avoid excessive installation or loosening of the push rod, ensure the accuracy of the injection action, and reduce the quality fluctuation of die-cast products caused by unstable transmission.

[0030] In summary, the synergistic effect of the various structures significantly improves the reliability and service life of the injection head in high-temperature, high-pressure, and high-friction die-casting environments.

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0032] Figure 1 This is a cross-sectional view of the injection head according to an embodiment of the present invention;

[0033] Figure 2 This is a top view of the injection head according to an embodiment of the present invention;

[0034] Figure 3 This is a half-sectional view of the injection head according to an embodiment of the present invention;

[0035] Figure 4 This is a front view of the injection head according to an embodiment of the present invention.

[0036] Explanation of reference numerals: 1. Piston head; 2. Cylindrical working part; 21. Receiving cavity; 3. Push rod connecting part; 31. Cylindrical connecting part; 32. Prismatic connecting part; 33. Connecting cavity; 34. Threaded connecting part; 4. Helical groove structure; 5. Copper alloy cladding layer; 6. Annular reinforcing band; 7. Annular retaining edge; 8. Annular rounded corner transition band. Detailed Implementation

[0037] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0038] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0039] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0040] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0041] like Figures 1 to 4 As shown, this embodiment discloses a laser-clad copper alloy die-casting machine injection head, an integral body made of high-temperature wear-resistant substrate, including: a cylindrical working part 2, a push rod connecting part 3, and a plunger head 1, which is covered with a copper alloy cladding layer 5. The plunger head 1, the cylindrical working part 2, and the push rod connecting part 3 are distributed sequentially along the axial direction.

[0042] Among them, the cylindrical working part 2 has an internal cavity 21 for storing coolant, and its outer peripheral wall surface is provided with a spiral groove structure 4.

[0043] The push rod connecting part 3 includes a cylindrical connecting part 31 and a prismatic connecting part 32; the cylindrical connecting part 31 is connected to one end of the cylindrical working part 2, and its outer peripheral wall surface is provided with a spiral groove structure 4; wherein, the push rod connecting part 3 has a connecting cavity 33, which passes through the cylindrical connecting part 31 and the prismatic connecting part 32, and has a threaded connecting part 34 for connecting the push rod;

[0044] The plunger head 1 is located at the end of the cylindrical working part 2 away from the prismatic connecting part 32, and the edge connecting the plunger head 1 to the cylindrical working part 2 is provided with an annular rounded transition band 8.

[0045] The copper alloy cladding layer 5 is uniformly covered on the spiral groove structure 4 of the cylindrical working part 2 and the cylindrical connecting part 31 by laser cladding process.

[0046] It should be further explained that the injection head in this embodiment adopts an integrated body design and is made of high-temperature wear-resistant substrate to ensure sufficient strength and heat resistance in the high-temperature environment of die casting, and to avoid deformation or failure of the body due to high temperature.

[0047] The receiving cavity 21 is used to install the coolant liner. During the die casting process, the coolant circulates through the liner, absorbing the heat generated by the injection head in contact with the molten metal, effectively reducing the surface temperature of the working part, preventing material softening or cladding layer peeling due to overheating, and extending the service life of the injection head.

[0048] A copper alloy cladding layer 5 is uniformly coated onto the spiral groove structure 4 of the cylindrical working part 2 and the cylindrical connecting part 31 using a laser cladding process. The spiral groove increases the contact area between the substrate and the cladding layer, enhances the bonding force between the two, and prevents the cladding layer from falling off. The copper alloy itself has good wear resistance and thermal conductivity, allowing it to directly contact the molten metal and reduce friction loss. At the same time, it quickly transfers heat to the internal coolant tank, improving heat dissipation efficiency.

[0049] The plunger head 1, as a component that directly contacts the molten metal, is used to stably push the molten metal. An annular rounded transition zone 8 is provided at the edge connecting to the cylindrical working part 2. This structure can disperse the stress concentration at the connection between the plunger head 1 and the working part during the injection process, and avoid cracking of the cladding layer or damage to the substrate caused by repeated impacts.

[0050] The push rod connecting part 3 includes a cylindrical connecting part 31 and a prismatic connecting part 32, with a through connecting cavity 33 (with a threaded connecting part 34) inside for fixing the push rod. The prismatic structure prevents the push rod from rotating relative to the injection head, ensuring the stability of the transmission.

[0051] Based on this, the injection head of this embodiment provides basic strength through a high-temperature wear-resistant substrate, the spiral groove and copper alloy cladding layer 5 enhance surface wear resistance and heat dissipation, the coolant liner achieves efficient cooling, the rounded corner transition of the plunger head 1 buffers stress, and the push rod connection 3 ensures stable transmission. The coordinated action of these structures ultimately improves the reliability and service life of the injection head in high-temperature, high-pressure, and high-friction die-casting environments.

[0052] In one possible embodiment, the copper alloy cladding layer 5 is a Cu-Ni-Cr copper alloy or a Cu-Al-Fe copper alloy.

[0053] Further explanation is needed regarding Cu-Ni-Cr alloys: the presence of nickel (Ni) enhances the alloy's high-temperature strength and corrosion resistance, while chromium (Cr) forms a dense oxide film, strengthening surface wear resistance and resistance to molten metal erosion. These alloys maintain stable mechanical properties even at high temperatures (often in contact with molten metal at 600-900℃ during die casting). When in direct contact with molten metal, they effectively reduce frictional losses and prevent the cladding layer from failing due to wear or corrosion.

[0054] Cu-Al-Fe copper alloys: The addition of aluminum (Al) significantly improves the alloy's strength and oxidation resistance, while iron (Fe) refines the grain and enhances wear resistance. They possess excellent thermal conductivity (copper-based alloys have good intrinsic thermal conductivity), allowing for rapid transfer of heat generated by the injection head's contact with the molten metal to the internal coolant liner. This, combined with circulating coolant, achieves efficient heat dissipation, preventing softening of the cladding layer or deformation of the substrate due to overheating.

[0055] The wear-resistant properties of copper alloy reduce frictional losses between the injection head and the tube, while its high thermal conductivity quickly transfers heat to the internal coolant liner (installed through the receiving cavity 21). The coolant circulates to absorb and discharge heat, reducing the surface temperature of the injection head and preventing material softening or cladding failure due to high temperatures.

[0056] The corrosion resistance of Cu-Ni-Cr copper alloys and the high strength of Cu-Al-Fe alloys, combined with a certain cladding thickness, provide sufficient wear protection and ensure long-term stable bonding between the cladding layer and the substrate, thus extending the service life of the injection head in high-temperature, high-pressure, and high-friction environments.

[0057] Based on this, the Cu-Ni-Cr and Cu-Al-Fe copper alloy cladding layers 5 improve the reliability and durability of the injection head by adapting material properties to working conditions, strengthening structural design, and optimizing performance through functional synergy.

[0058] In one possible embodiment, the high-temperature wear-resistant substrate is any one of ductile iron, 42CrMo alloy steel, or H13 hot work die steel.

[0059] Further explanation is needed regarding the excellent casting properties of ductile iron. Furthermore, the spheroidal graphite structure formed by graphite spheroidization imparts high wear resistance (graphite reduces friction) and a certain degree of heat resistance. Its matrix strength can support the mechanical stresses (such as the thrust transmitted by the push rod) experienced by the injection head during injection, preventing deformation or breakage of the main body.

[0060] 42CrMo alloy steel is a high-strength alloy structural steel with excellent comprehensive mechanical properties, maintaining high strength and toughness even at high temperatures. Its high hardenability ensures uniform overall performance of thick-section components (such as the injection head body), making it suitable for applications requiring high loads and impacts. It can effectively resist stress concentration caused by the rapid filling speed and high pressure of molten metal during injection.

[0061] H13 hot work die steel has excellent thermal strength, thermal fatigue resistance and wear resistance, and is suitable for high temperature conditions or high frequency injection scenarios (such as continuous production). Its high temperature stability can prevent the body from softening due to long-term heating and avoid the cladding layer from falling off due to the deformation of the base material.

[0062] Based on this, ductile iron, 42CrMo alloy steel, and H13 hot work die steel adapt to different die casting conditions through their respective material properties (strength, heat resistance, and thermal conductivity), providing structural support for the injection head. At the same time, they work in synergy with the cladding layer and coolant system to ultimately improve the reliability and service life of the injection head in high temperature, high pressure, and high friction environments.

[0063] In one possible embodiment, the copper alloy cladding layer 5 has a cladding thickness of 1.0-3.0 mm.

[0064] Further explanation is needed regarding the fact that the injection head frequently comes into contact with high-temperature molten metal during the die-casting process and endures high-pressure friction during the injection action. If the cladding layer is too thin (<1.0 mm), it is easily worn away rapidly during long-term friction, causing the substrate to be directly exposed to the molten metal, losing its protective function and accelerating the failure of the injection head. If it is too thick (>3.0 mm), the residual stress (mainly tensile stress) generated by the rapid cooling of the laser cladding layer will increase significantly. Once it exceeds the bonding strength between the cladding layer and the substrate, it will cause the cladding layer to crack or fall off. Therefore, a thickness range of 1.0-3.0 mm balances "wear-resistant protection" and "bonding stability," ensuring that the cladding layer can effectively resist wear while maintaining a tight bond with the substrate during long-term use.

[0065] In one possible embodiment, the copper alloy cladding layer 5 extends toward the plunger head 1 and completely covers the annular rounded transition zone 8.

[0066] It needs further explanation that the plunger head 1, as the core component that directly contacts the molten metal and pushes it to fill the mold, must withstand high-frequency impact stress (such as the recoil force of the molten metal and the push rod thrust) during the injection process.

[0067] After the copper alloy cladding layer 5 completely covers the annular rounded corner transition zone 8, the stress risk is mitigated in the following ways:

[0068] Material properties buffering: Copper alloys (such as Cu-Ni-Cr series) have better toughness than the base material, which can absorb some of the impact energy and reduce the stress peak;

[0069] Enhanced geometric continuity: The rounded corner structure of the cladding layer and the transition zone forms a continuous curved surface, avoiding local stress concentration caused by sharp edges and making the stress distribution more uniform.

[0070] Copper alloys have a higher hardness than the base material and can maintain stable wear resistance at high temperatures, reducing frictional loss between the transition zone and the feed tube or molten metal.

[0071] Corrosion barrier: Copper alloys have low chemical affinity for molten metals (such as aluminum) (molten aluminum has poor wettability on copper), which can prevent molten metal from penetrating to the surface of the substrate and prevent the substrate from being corroded or embrittled.

[0072] Based on this, the copper alloy cladding layer 5 covers the annular rounded corner transition zone 8, which protects against stress concentration, enhances wear and corrosion resistance, and matches the geometric structure, ultimately improving the reliability and service life of the injection head under high-frequency impact and high-temperature friction conditions.

[0073] Preferably, the copper alloy cladding layer 5 at the annular rounded corner transition zone 8 is locally thickened to form an annular reinforcing zone 6, the thickness of which is 1.2–1.3 times that of the copper alloy cladding layer 5 in the adjacent area, and the width is 5–8 mm.

[0074] Further explanation is needed: during injection molding, the rounded edges of the transition zone are prone to sliding friction with the tube wall, leading to a faster local wear rate. The thickened cladding layer provides more "material reserves" for wear resistance, ensuring that even if the surface layer thins due to friction or corrosion, it still maintains a sufficient thickness (≥0.8mm) to continue protecting the substrate and prevent premature exposure.

[0075] Based on this, the corrosion resistance of the copper alloy, combined with the thickened design, further reduces the wear rate of the transition zone and extends the maintenance cycle of the injection head.

[0076] In one possible embodiment, the spiral groove structure 4 is a continuous single-head or multi-head spiral groove;

[0077] The spiral groove has a depth of 0.2-0.4 mm, a groove width of 0.3-0.8 mm, and a ridge spacing of 0.5-1.5 mm between adjacent spiral grooves.

[0078] Further explanation is needed regarding the spiral grooves, which, through their alternating groove-ridge microstructure, create an interlocking structure at the interface between the cladding layer and the substrate. When the cladding layer tends to peel due to thermal or mechanical stress, the groove walls exert lateral resistance on the cladding layer (similar to a tenon-and-mortise structure), significantly enhancing the shear resistance of the bonding interface.

[0079] The spiral groove increases the contact area between the substrate and the cladding layer. During laser cladding, the copper alloy melt in the molten pool can penetrate into the groove more fully, forming a more uniform metallurgical bonding layer with the substrate surface, reducing defects (such as pores and cracks) caused by incomplete fusion at the interface.

[0080] The depth is 0.2-0.4 mm.

[0081] If the depth is too shallow (<0.2mm), the mechanical interlocking "locking" effect is weak, and the cladding layer is prone to peeling due to thermal stress. If it is too deep (>0.4mm), the remaining wall thickness of the substrate is reduced, which may decrease the overall strength of the substrate (e.g., the tensile strength of ductile iron substrate drops from 400MPa to below 350MPa), causing the injection head to deform or break under high pressure. A depth of 0.2-0.4mm ensures the mechanical interlocking effect while avoiding excessive loss of substrate strength.

[0082] Groove width (0.3-0.8mm) and ridge spacing (0.5-1.5mm):

[0083] If the groove width is too narrow (<0.3mm), the cladding powder will not be able to fill the groove evenly, which will easily lead to incomplete fusion defects; if the groove width is too wide (>0.8mm), microcracks will easily be generated in the center of the groove due to volume shrinkage when the molten pool cools.

[0084] If the ridge spacing is too narrow (<0.5mm), the ridge may melt and collapse during the cladding process due to excessive laser heat input, damaging the structure; if the ridge spacing is too wide (>1.5mm), the "interlocking" density of the mechanical interlocking will decrease (the number of grooves per unit area will decrease), and the bonding strength will decrease.

[0085] The combination of a groove width of 0.3-0.8 mm and a ridge spacing of 0.5-1.5 mm ensures the uniformity of cladding powder filling and the stability of the ridge structure, while the number of grooves per unit area provides sufficient mechanical interlocking density.

[0086] Single-head spiral groove: The groove has strong continuity, and the stress distribution of the cladding layer in the spiral direction is more uniform.

[0087] Multi-head spiral grooves: The intersections of the grooves form a grid-like locking structure, resulting in higher mechanical locking density and more effective resistance to circumferential peeling of the cladding layer.

[0088] Based on this, the structural parameters of the spiral groove (depth, groove width, ridge spacing) and the single / multi-head design, by strengthening the bonding between the cladding layer and the substrate, balancing structural strength and process feasibility, and adapting to different working conditions, ultimately improve the reliability and service life of the injection head in high temperature, high pressure, and high friction environments.

[0089] Preferably, the cross-sectional shape of the spiral groove is V-shaped or U-shaped with a rounded bottom, and the radius of the bottom fillet R is ≥0.1mm; the spiral angle of the spiral groove is 30° to 60° and is evenly distributed on the outer peripheral wall surface of the cylindrical working part 2 and the cylindrical connecting part 31.

[0090] It needs further explanation that the V-groove has an acute angle in its cross-section and steep walls. Its core advantage lies in enhancing the mechanical interlocking effect: the steep groove walls form a "barbed" interlocking structure with the cladding layer. When the cladding layer tends to peel off due to thermal or mechanical stress, the groove walls exert greater lateral resistance on the cladding layer, significantly improving the interface's shear resistance.

[0091] The U-shaped groove with rounded corners and curved walls offers a key advantage in mitigating stress concentration: the rounded corners disperse stress at the groove bottom, reducing the risk of cracking. The curved groove walls also result in smoother contact with the cladding layer, leading to a more uniform distribution of shrinkage stress during molten pool cooling and improved density of the cladding layer.

[0092] In one possible embodiment, the end face of the plunger head 1 is a flat surface or a slightly convex curved surface, and the radius R of the rounded corner transition zone 8 is 0.5–1.0 mm.

[0093] Further explanation is needed regarding the plunger head 1 end face, which is the core interface that directly pushes the molten metal. Its shape improves injection efficiency and structural life by influencing the flow state of the molten metal and the distribution of contact stress.

[0094] (1) The contact area between the flat end face and the molten metal is large and symmetrical. During injection, the molten metal is pushed at the same speed at each point on the end face, which can reduce the eddy current caused by the difference in flow velocity. At the same time, the back pressure of the molten metal is applied evenly to the end face, avoiding local high stress.

[0095] (2) When the edge of the micro-convex curved surface comes into contact with the molten metal, the contact point gradually expands from the center to the edge, which can guide the molten metal to spread evenly in all directions and reduce the molten metal stagnation caused by the dead zone of flow.

[0096] The R=0.5–1.0mm design reduces the stress concentration factor through "moderate rounded transition". At the same time, the rounded corner radius is adapted to the cladding process, which can ensure that the thickness of the cladding layer is uniform in the rounded corner area. It also forms a continuous protective interface with the cladding layer of the plunger head 1 and the working part, avoiding stress concentration at the interface.

[0097] In one possible embodiment, the connecting cavity 33 forms an annular retaining flange 7 at one end port facing the receiving cavity 21 and the upper edge of the threaded connection portion 34.

[0098] It needs further explanation that the annular retaining edge 7 at the upper edge of the threaded connection part 34 and the port of the connecting cavity 33 serves as a limit to prevent the push rod from being over-installed or loosened, thus ensuring the accuracy of the injection action.

[0099] The above embodiments are merely preferred embodiments of this utility model and should not be construed as limiting the scope of protection of this utility model. Any non-substantial changes and substitutions made by those skilled in the art based on this utility model shall fall within the scope of protection claimed by this utility model.

Claims

1. A laser-clad copper alloy die-casting machine injection head, characterized in that, The unibody design, made of high-temperature wear-resistant substrate, includes: The cylindrical working part has an internal cavity for storing coolant, and its outer peripheral wall surface has a spiral groove structure. The push rod connecting part includes a cylindrical connecting part and a prismatic connecting part; the cylindrical connecting part is connected to one end of the cylindrical working part, and its outer peripheral wall surface is provided with a spiral groove structure; wherein, the push rod connecting part has a connecting cavity, the connecting cavity passes through the cylindrical connecting part and the prismatic connecting part, and has a threaded connecting part for connecting the push rod; The plunger head is located at the end of the cylindrical working part away from the prismatic connecting part, and the edge where it connects with the cylindrical working part is provided with an annular rounded transition zone; A copper alloy cladding layer is uniformly applied to the spiral groove structure of the cylindrical working part and the cylindrical connecting part using a laser cladding process.

2. The laser-clad copper alloy die-casting machine injection head according to claim 1, characterized in that, The high-temperature wear-resistant base material is any one of ductile iron, 42CrMo alloy steel, or H13 hot work die steel.

3. The laser-clad copper alloy die-casting machine injection head according to claim 2, characterized in that, The thickness of the copper alloy cladding layer is 1.0-3.0 mm.

4. The laser-clad copper alloy die-casting machine injection head according to claim 3, characterized in that, The copper alloy cladding layer extends toward the plunger head and completely covers the annular rounded transition zone.

5. The laser-clad copper alloy die-casting machine injection head according to claim 4, characterized in that, The copper alloy cladding layer at the annular rounded corner transition zone is locally thickened, forming an annular reinforcing zone.

6. The laser-clad copper alloy die-casting machine injection head according to any one of claims 1-5, characterized in that, The spiral groove structure is a continuous single-head or multi-head spiral groove; The spiral groove has a depth of 0.2-0.4 mm, a groove width of 0.3-0.8 mm, and a ridge spacing of 0.5-1.5 mm between adjacent spiral grooves.

7. The laser-clad copper alloy die-casting machine injection head according to claim 6, characterized in that, The cross-sectional shape of the spiral groove is V-shaped or U-shaped with a rounded bottom, and the radius of the bottom fillet R is ≥ 0.1 mm; the spiral angle of the spiral groove is 30° to 60° and is evenly distributed on the outer peripheral wall surface of the cylindrical working part and the cylindrical connecting part.

8. The laser-clad copper alloy die-casting machine injection head according to claim 1, characterized in that, The end face of the plunger head is a flat surface or a slightly convex curved surface, and the radius R of the rounded corner transition zone is 0.5–1.0 mm.

9. The laser-clad copper alloy die-casting machine injection head according to claim 1, characterized in that, The connecting cavity forms an annular retaining edge at one end of the receiving cavity and the upper edge of the threaded connection.

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