Laser cladding titanium alloy die-casting machine injection head

Abstract

The utility model discloses a laser-cladded titanium 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 titanium alloy cladding layer, a containing cavity for storing a cooling liquid inner container is formed in the cylindrical working part, and concave-convex textures are 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 concave-convex textures are 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 edge of the plunger head is chamfered, and the plunger head is arranged on the end part, far away from the prismatic connecting part, of the cylindrical working part; and the titanium alloy cladding layer uniformly covers the concave-convex textures 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 titanium alloy die-casting machine injection head. Background Technology

[0002] As a core component of die-casting equipment, the injection head of a die-casting machine is subjected to long-term erosion, corrosion, and high-pressure impact (>100MPa) from high-temperature molten metal (such as aluminum alloys and magnesium alloys). Traditional injection heads are mostly made of tool steel or high-temperature alloys, but these methods present the following problems in practical applications:

[0003] High-temperature wear: The temperature of molten metal can reach over 600℃, which leads to a decrease in the surface hardness of the injection head, accelerating wear and shortening its service life.

[0004] Thermal fatigue cracking: Frequent hot and cold cycles (20℃ to 600℃) can easily cause surface cracking, reducing structural reliability.

[0005] To address the aforementioned problems, existing technologies attempt to employ the following solutions:

[0006] Applying a coating (such as a plating or thermal spray coating) to the substrate surface can improve surface hardness, but the coating has low bonding strength with the substrate and is prone to peeling off under high pressure, thus failing to provide long-term effective protection for the substrate.

[0007] Overall material upgrades (such as tungsten-cobalt alloys): While significantly improving wear resistance, they are costly and difficult to process, making large-scale application difficult.

[0008] In addition, the connection between the cylindrical working part of the injection head and the plunger head has a large stress concentration coefficient due to the abrupt change in geometry during high-pressure injection, which becomes a high-risk area for crack initiation and results in insufficient local protection.

[0009] In summary, there is an urgent need for an innovative injection head solution that combines high wear resistance, thermal fatigue resistance, strong bonding force, and cost-effectiveness to overcome the limitations of existing technologies. Utility Model Content

[0010] In order to overcome the shortcomings of the existing technology, the purpose of this utility model is to provide a laser cladding titanium alloy die casting machine injection head, so as to solve the technical problems of insufficient wear resistance, thermal fatigue resistance and structural reliability of traditional injection heads under high temperature, high pressure and cold and hot cycle conditions.

[0011] To solve the above problems, the technical solution adopted by this utility model is as follows:

[0012] A laser-clad titanium alloy die-casting machine injection head, with a one-piece body made of a high-temperature wear-resistant substrate, comprising:

[0013] The cylindrical working part has an internal cavity for storing coolant, and its outer peripheral wall surface has a textured surface.

[0014] 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 concave and convex textures; 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;

[0015] The plunger head, with its chamfered edges, is located at the end of the cylindrical working part away from the prismatic connecting part;

[0016] The titanium alloy cladding layer is uniformly applied to the textured surface of the cylindrical working part and the cylindrical connecting part using a laser cladding process.

[0017] Preferably, the high-temperature wear-resistant substrate is any one of ductile iron, 42CrMo alloy steel, or H13 hot work die steel.

[0018] Preferably, the cladding thickness of the titanium alloy cladding layer is 0.5-2 mm.

[0019] Preferably, the titanium alloy cladding layer extends toward the plunger head and completely covers the connection between the cylindrical working part and the plunger head.

[0020] Preferably, the titanium alloy cladding layer at the connection between the cylindrical working part and the plunger head is locally thickened to form an annular reinforcing band.

[0021] Preferably, the textured surface is a continuous or discontinuous geometric structure;

[0022] When the geometric structure is continuous, the depth of the raised texture is 0.1-0.5 mm, the width is 0.3-1.0 mm, and the spacing between adjacent textures is 0.5-2.0 mm.

[0023] Preferably, the cross-sectional shape of the textured surface is one of sawtooth, wavy, or trapezoidal, and is evenly distributed on the outer peripheral wall surface of the cylindrical working part and the cylindrical connecting part.

[0024] Preferably, the end face of the plunger head is a flat surface or a slightly convex curved surface, and its chamfer angle is 30° to 45°.

[0025] Preferably, the connecting cavity has an annular retaining edge at one end facing the receiving cavity and at the upper edge of the threaded connection portion.

[0026] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0027] (1) Significantly improves wear resistance and service life

[0028] The titanium alloy cladding layer is uniformly covered on the surface of the substrate through laser cladding process. Combining the high temperature stability of titanium alloy with the toughness of the substrate, it can effectively resist the erosion and wear of molten metal and extend the service life of the injection head.

[0029] (2) Enhance the bonding strength between the cladding layer and the substrate

[0030] Bionic surface texture design: The uneven texture on the surface of the cylindrical working part and the connecting part forms a mechanical interlocking structure, which enables the cladding layer to achieve metallurgical bonding with the substrate. The bonding strength is significantly better than that of traditional coatings or thermal spray coatings, avoiding the risk of peeling under high pressure impact.

[0031] Texture optimization: Evenly distributed serrated / wavy / trapezoidal textures provide a "rivet-like" anchoring effect, resisting axial shear forces. Texture spacing acts as a stress buffer zone, absorbing thermal deformation during thermal cycling and inhibiting crack propagation.

[0032] (3) Effectively inhibits thermal fatigue cracking

[0033] Annular reinforcement band design: At the connection between the cylindrical working part and the plunger head, the cladding layer is locally thickened to form a smooth gradient transition: reducing the stress concentration factor caused by geometric abrupt changes and reducing the risk of crack initiation; the thickened part provides wear allowance and extends the maintenance cycle.

[0034] Overall thermal barrier effect: The cladding layer completely covers the joint, reducing the temperature fluctuation amplitude, dispersing thermal stress, and improving thermal fatigue resistance.

[0035] (4) Optimize structural reliability

[0036] Proper plunger head chamfer design (30°–45°):

[0037] Eliminate stress concentration at sharp edges, absorb differences in thermal expansion, and avoid plastic deformation (<30° residual stress, >45° reduced crush resistance).

[0038] Modular connection structure:

[0039] Prismatic connectors (such as hexagonal prisms) and through-type connecting cavities ensure anti-rotation properties and high load-bearing capacity of the push rod installation;

[0040] The annular flange at the connection cavity port disperses axial pressure and protects the thread root from overload.

[0041] This invention solves the core problems of high-temperature wear and thermal fatigue cracking of traditional injection heads through innovative titanium alloy laser cladding process, biomimetic surface texture, stress-optimized structure (ring reinforcement band, chamfer design) and modular connection, significantly improving wear resistance, thermal fatigue resistance and structural reliability.

[0042] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0043] Figure 1 This is a cross-sectional view of the injection head according to an embodiment of the present invention;

[0044] Figure 2 This is a top view of the injection head according to an embodiment of the present invention;

[0045] Figure 3 This is a half-sectional view of the injection head according to an embodiment of the present invention.

[0046] The reference numerals in the attached diagram are as follows: 1. Piston head; 2. Cylindrical working part; 21. Receiving cavity; 3. Push rod connection part; 31. Cylindrical connection part; 32. Prismatic connection part; 33. Connection cavity; 34. Threaded connection part; 4. Textured surface; 5. Titanium alloy cladding layer; 6. Annular reinforcing band; 7. Annular retaining edge. Detailed Implementation

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] like Figures 1 to 3 As shown, this embodiment discloses a laser-clad titanium 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 titanium 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.

[0052] 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 textured surface 4.

[0053] 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 textured surface 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;

[0054] The plunger head 1 has a chamfered edge and is located on the end of the cylindrical working part 2 away from the prismatic connecting part 32;

[0055] The titanium alloy cladding layer 5 is uniformly covered on the textured surface 4 of the cylindrical working part 2 and the cylindrical connecting part 31 by laser cladding process.

[0056] It should be further explained that this embodiment proposes an integrated pressure head for titanium alloy laser cladding, and achieves a performance leap through the following core innovations:

[0057] (1) Synergistic optimization of substrate and cladding layer: Using high temperature wear-resistant substrate (such as H13 hot work die steel) as the base, a titanium alloy layer is laser clad in the key area, combining the high temperature stability of titanium alloy with the toughness of substrate; and the cladding layer and the substrate form a metallurgical bond, which is significantly better than the existing coating and thermal spray coating.

[0058] (2) Enhanced biomimetic surface texture: The concave and convex texture 4 design of the working part and the connecting part makes the cladding layer form a mechanical interlocking structure, which significantly improves the bonding strength;

[0059] (3) Modular connection structure: The prism-shaped connection part 32 (such as a hexagonal prism) and the threaded connection part 34 of the connection cavity 33 ensure the anti-rotation performance and high load-bearing capacity of the push rod installation.

[0060] 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. The selected substrate, combined with integral molding, not only avoids the risks of stress concentration and seal failure associated with split structures, but also ensures that the injection head maintains structural integrity and resistance to deformation in high-temperature environments above 600°C.

[0061] In one possible embodiment, the titanium alloy cladding layer 5 is a β-type titanium alloy. The β-type titanium alloy is any one of Ti-5Al-5Mo-5V-3Cr, Ti-10V-2Fe-3Al, or Ti-15V-3Cr-3Sn-3Al.

[0062] The working temperature of the injection head can reach over 600℃. β-type titanium alloys have better phase stability, creep resistance and oxidation resistance at high temperatures, which is superior to α-type or α+β-type titanium alloys (such as Ti-6Al-4V).

[0063] β-type titanium alloys can achieve high strength and hardness through laser cladding while maintaining good toughness, significantly improving wear resistance.

[0064] Laser cladding technology for β-type titanium alloys is mature, with good molten pool fluidity, low crack sensitivity, and easy metallurgical bonding with high-temperature wear-resistant substrates (such as H13 steel), reducing interface defects.

[0065] In one possible embodiment, the cladding thickness of the titanium alloy cladding layer 5 is 0.5-2 mm. The lower limit of 0.5 mm ensures that the cladding layer completely covers surface defects of the substrate (such as microcracks and pores), preventing substrate erosion caused by molten metal penetration under high-pressure injection (>100 MPa). The upper limit of 2 mm prevents interface stress concentration caused by excessively thick coatings due to mismatch in thermal expansion coefficients.

[0066] Background Description: Due to the abrupt change in geometry at the connection between the cylindrical working part 2 and the plunger head 1, a stress concentration factor ≥3.0 is generated at high-pressure injection (>100MPa), which is much higher than in other areas, significantly increasing the risk of crack initiation. During the injection cycle (20℃ to 600℃), the difference in thermal expansion coefficients between the titanium alloy matrix and the cladding layer generates periodic shear stress at the connection interface, inducing thermal fatigue cracks.

[0067] Based on this: In one possible embodiment, the titanium alloy cladding layer 5 extends toward the plunger head 1 and completely covers the connection between the cylindrical working part 2 and the plunger head 1.

[0068] Further explanation is needed: the cladding layer covers the chamfered area at the joint, transforming the sharp angle transition into a smooth gradient and reducing the stress concentration factor. The continuous cladding layer creates an overall thermal barrier effect during thermal cycling, reducing temperature fluctuations and thermal stress amplitude in the joint area.

[0069] Preferably, the titanium alloy cladding layer 5 at the connection between the cylindrical working part 2 and the plunger head 1 is locally thickened to form an annular reinforcing band 6. The thickness of this band is 1.2–1.3 times that of the adjacent titanium alloy cladding layer 5, and its width is 5–8 mm. This thickened portion further reduces the stress concentration factor and provides wear allowance, extending the regrinding cycle. The 5–8 mm width effectively covers areas with high stress gradients.

[0070] In one possible embodiment, the bump texture 4 is a continuous or discontinuous geometric structure;

[0071] When the geometric structure is continuous, the depth of the bump texture 4 is 0.1-0.5mm, the width is 0.3-1.0mm, and the spacing between adjacent textures is 0.5-2.0mm.

[0072] Due to the difference in thermal expansion coefficients, the interface between the substrate and the cladding layer is prone to shear stress during thermal cycling, resulting in insufficient bonding strength at the traditional smooth interface. The textured surface 4 significantly improves the bonding strength through a mechanical interlocking effect.

[0073] The injection head withstands impacts exceeding 100 MPa and erosion from high-temperature molten metal during the injection stage. The textured structure forms a micro-turbulent damping layer, reducing the direct erosion of the surface by the molten metal and significantly decreasing the wear rate.

[0074] Textured grooves (0.5–2.0 mm spacing) act as stress buffers, absorbing thermal deformation during thermal cycling (20°C to 600°C) and inhibiting crack propagation.

[0075] Preferably, the cross-sectional shape of the texture 4 is one of sawtooth, wave, or trapezoid, and is evenly distributed on the outer peripheral wall surface of the cylindrical working part 2 and the cylindrical connecting part 31.

[0076] Among them, the inclined tooth profile of the serrated texture provides a large mechanical locking effect, and the peak-valley structure of the serrated texture makes the cladding material fill into "rivet-like" anchor points to resist the axial shear force during high-pressure injection.

[0077] The wavy texture can smoothly transition and eliminate stress concentration, thus improving thermal fatigue life; the symmetrical distribution of wave peaks can evenly disperse thermal stress, making it suitable for cylindrical working parts 2 that experience frequent temperature changes.

[0078] The trapezoidal slope of the trapezoidal texture increases the cladding contact area, while the bottom width ensures the load-bearing strength of the substrate.

[0079] In one possible embodiment, the end face of the plunger head 1 is a flat or slightly convex surface with a chamfer angle of 30° to 45°. A 30° to 45° chamfer can effectively reduce the stress concentration factor and absorb the expansion difference in thermal cycles (20°C to 600°C), which helps to improve thermal fatigue life.

[0080] <30°: Sharp edge effect remains, and stress concentration at the chamfer root is still significant;

[0081] >45°: The effective load-bearing area is reduced, the crush resistance decreases, and plastic deformation is more likely to occur.

[0082] In one possible embodiment, an annular retaining flange 7 is formed at one end of the connecting cavity 33 facing the receiving cavity 21 and at the upper edge of the threaded connection portion 34. The stepped transition of the annular retaining flange 7 can effectively reduce the stress concentration factor. At the same time, the retaining flange acts as a rigid support ring to disperse the axial pressure transmitted by the push rod and prevent the root of the thread from bearing excessive load.

[0083] 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 titanium 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 textured surface. 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 concave and convex textures; 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, with its chamfered edges, is located at the end of the cylindrical working part away from the prismatic connecting part; The titanium alloy cladding layer is uniformly applied to the textured surface of the cylindrical working part and the cylindrical connecting part using a laser cladding process.

2. The laser-clad titanium 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 titanium alloy die-casting machine injection head according to claim 2, characterized in that, The thickness of the titanium alloy cladding layer is 0.5-2 mm.

4. The laser-clad titanium alloy die-casting machine injection head according to claim 3, characterized in that, The titanium alloy cladding layer extends toward the plunger head and completely covers the connection between the cylindrical working part and the plunger head.

5. The laser-clad titanium alloy die-casting machine injection head according to claim 4, characterized in that, The titanium alloy cladding layer at the connection between the cylindrical working part and the plunger head is locally thickened, forming an annular reinforcing band.

6. The laser-clad titanium alloy die-casting machine injection head according to any one of claims 1-5, characterized in that, The raised or recessed texture is a continuous or discontinuous geometric structure; When the geometric structure is continuous, the depth of the raised texture is 0.1-0.5 mm, the width is 0.3-1.0 mm, and the spacing between adjacent textures is 0.5-2.0 mm.

7. The laser-clad titanium alloy die-casting machine injection head according to claim 6, characterized in that, The cross-sectional shape of the textured surface is one of sawtooth, wave, or trapezoid, and it is evenly distributed on the outer peripheral wall surface of the cylindrical working part and the cylindrical connecting part.

8. The laser-clad titanium alloy die-casting machine injection head according to claim 1, characterized in that, The end face of the plunger head is a flat or slightly convex curved surface, with a chamfer angle of 30° to 45°.

9. The laser-clad titanium 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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