Die-casting machine punch with coating structure as well as preparation method and application of die-casting machine punch

Abstract

The invention provides a die-casting machine punch with a coating structure and a preparation method of the die-casting machine punch. The punch comprises a base body and a high-temperature wear-resistant coating arranged on the outer surface of the front end of the base body in a surrounding mode in a cladding mode. The thermal expansion coefficient of the prepared high-temperature wear-resistant coating is similar to that of a steel and iron material, the high-temperature wear-resistant coating can be metallurgically bonded with a steel and iron matrix of the punch, the surface hardness reaches HRC64 or above, the high-temperature wear resistance and molten metal corrosion resistance are excellent, the thermal expansion coefficient is low, the service life of the punch is greatly prolonged, and the service life of the punch is prolonged. The cost is effectively reduced, the production efficiency is improved, and the stability of die-casting product quality is ensured. According to the prepared die-casting machine punch with the coating structure, deposition can be carried out on the surfaces of common base materials such as cast iron, carbon steel or alloy steel, deposition preparation is only carried out on the front end part of the punch, the process is simple, the preparation cost of a workpiece is greatly reduced, raw materials are saved, and the die-casting machine punch with the coating structure can be widely applied to a die-casting machine under the high-temperature abrasion working condition; and the service life of the punch is greatly prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of die-casting machine punches, and in particular relates to a die-casting machine punch with a cladding structure and a preparation method thereof, and also relates to the application of the die-casting machine punch with a cladding structure. Background Art

[0002] Die casting machine is a machine used for pressure casting, including hot pressure chamber and cold pressure chamber. Under the action of pressure, the die casting machine hydraulically injects molten metal into the mold for cooling and forming. After the mold is opened, solid metal castings can be obtained. It is widely used in the automotive, home appliance and other industries.

[0003] The punch is an important component of the die-casting machine that directly squeezes the molten metal into the mold for forming. When the die-casting machine is working, the die-casting machine punch is in direct contact with the high-temperature die-casting metal liquid. The punch and the barrel are constantly sliding and rubbing back and forth, and are subjected to cold and hot temperature changes for a long time. In addition, penetration and adhesion occur between the molten metal liquid and the punch material, causing the punch to be easily worn and damaged by thermal fatigue. Once the surface wear of the punch exceeds the tolerance, the entire punch will be scrapped, which seriously reduces the service life of the punch. At present, the die-casting machine punches used by most manufacturers in my country are integral structural parts, especially the large imported die-casting machine punches. Due to their large size and expensive material body, the waste caused by abandonment is large, and it is not conducive to energy saving and environmental protection.

[0004] Based on this, it is a technical problem that urgently needs to be solved to provide a die-casting machine punch and a preparation method thereof, which can improve the surface hardness and high-temperature wear resistance of the punch, effectively reduce the penetration and adhesion between the molten metal and the punch material, and reduce the tendency of thermal alternation stress cracking, so as to achieve a significant increase in the service life of the die-casting machine punch. Summary of the invention

[0005] One of the purposes of the present invention is to provide a die-casting machine punch with a coating structure to address the shortcoming of the existing die-casting machine punch having an insufficient service life. The coating structure can not only improve the surface hardness and high-temperature wear resistance of the punch, but also effectively reduce the penetration and adhesion between the molten metal and the punch material, reduce the tendency of thermal alternating stress cracks, and greatly improve the service life of the punch.

[0006] The second object of the present invention is to provide a method for preparing a punch of a die-casting machine with a coating structure, which can improve the surface hardness and high-temperature wear resistance of the punch, effectively reduce the penetration and adhesion between the molten metal and the punch material, reduce the tendency of thermal alternation stress cracking, and greatly increase the service life of the punch.

[0007] A third object of the present invention is to provide a die-casting machine punch with a coating structure for use in a die-casting machine.

[0008] The technical solution adopted by the present invention to achieve one of the purposes is: to provide a die-casting machine punch with a coating structure, comprising: a substrate, and a high-temperature wear-resistant coating arranged on the outer surface of the front end of the substrate in a cladding manner; The raw material composition of the high temperature wear-resistant coating includes, by weight percentage: Mo: 20%-25%, Cr: 10%-15%, Zr: 2%-5%, Co: 5%-10%, Si: 1.5%-2.5%, C: 2%-4%, B: 1.5%-3%, Ti: 2%-5%, and the balance is Fe.

[0009] Furthermore, the material of the substrate includes one of cast iron, carbon steel or alloy steel.

[0010] Furthermore, the high temperature wear-resistant coating has a thickness of 1-5 mm and a width of 10-30 mm.

[0011] The raw material composition of the high temperature wear-resistant coating used in the present invention is a self-fluxing alloy, and the surface coating formed by cladding is composed of a high temperature resistant Fe-Cr-Co alloy bonding phase and a high hardness Mo 2 FeB 2 、ZrB、TiC、CrB 2 It is composed of a variety of composite hard phases. This in-situ formed composite metal ceramic material has excellent high-temperature wear resistance and resistance to erosion by molten metal, and has a low thermal expansion coefficient similar to that of steel materials. It can be metallurgically bonded with the steel substrate of the punch to ensure the bonding strength between the coating and the substrate, and avoid the problem of coating peeling caused by thermal alternating stress during use. In addition, the raw materials of the high-temperature wear-resistant coating provided by the present invention can self-deoxidize and slag during the cladding process to avoid defects such as holes and cracks at the interface between the substrate and the coating.

[0012] The present invention can not only improve the surface hardness and high-temperature wear resistance of the punch, but also effectively reduce the penetration and adhesion between the molten metal and the punch material, reduce the tendency of thermal alternating stress cracks, fully meet the working condition requirements of the die-casting machine punch, greatly improve the service life of the punch in production applications, effectively reduce costs, improve production efficiency and ensure the stability of the quality of die-casting products.

[0013] The technical solution adopted by the present invention to achieve the second purpose is: to provide a method for preparing a die-casting machine punch with a cladding structure according to one of the purposes of the present invention, comprising the following steps: S1, preparing a punch blank, and preheating and heat-insulating the punch blank; S2, mixing the raw materials of the high temperature wear-resistant coating to obtain the cladding powder, drying it, then filling it with an outer skin, and drawing it to obtain a flux-cored welding wire; S3, forming a high-temperature wear-resistant coating on the outer surface of the front end of the preheated punch blank by cladding the flux-cored welding wire; S4. Finish-process the clad punch to a specified size to obtain a clad structure die-casting machine punch.

[0014] Furthermore, in step S1, the punch blank is made of a base material by casting or machining, and the preheating temperature of the punch blank is 200-300°C, and the insulation time is 2-3 hours. In the present invention, the uniformity of the temperature distribution of the punch blank and the quality of the subsequent surface cladding layer can be ensured by preheating and insulation treatment of the punch blank.

[0015] Furthermore, in step S2, the raw materials of the high temperature wear-resistant coating are all in powder form, with a particle size of 25-150 μm.

[0016] Furthermore, in step S2, the mixing is performed by a mixing device, and the mixing time is 2-3 hours. The mixing process can improve the uniformity of the raw material powder dispersion, which is beneficial to subsequent processing.

[0017] Furthermore, in step S2, the outer skin of the flux-cored welding wire is low carbon steel or stainless steel, and the diameter of the flux-cored welding wire is 2.0-4.0 mm. In the present invention, the composition and material of the outer skin of the flux-cored welding wire can also be adjusted according to specific needs to improve the selection range of the outer skin and the performance regulation of the high temperature wear-resistant coating.

[0018] Furthermore, the cladding method includes one or more combinations of plasma cladding, argon arc cladding, and submerged arc welding. In the present invention, the cladding method has great selectivity for rapid processing. Specifically, a suitable process can be selected according to factors such as the substrate material and the raw material composition of the high-temperature wear-resistant coating to clad the flux-cored wire on the substrate surface.

[0019] Preferably, the process parameters of the plasma cladding include: current of 200-350A, voltage of 48-60V, and cladding speed of 38-45mm / min.

[0020] Preferably, the process parameters of the argon arc cladding include: current of 280-400A, voltage of 26-32V, and cladding speed of 30-35mm / min.

[0021] Preferably, the process parameters of the submerged arc welding include: current of 480-560A, voltage of 32-36V, and cladding speed of 55-65mm / min.

[0022] The technical solution adopted by the present invention to achieve the third purpose is: to provide a die-casting machine, which includes a die-casting machine punch with a coating structure according to one of the purposes of the present invention, or a die-casting machine punch with a coating structure prepared by the preparation method described in the second purpose of the present invention.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) The cladding structure die-casting machine punch provided by the present invention has a surface cladding layer composed of a high-temperature resistant Fe-Cr-Co alloy bonding phase and a high-hardness Mo 2 FeB 2 、ZrB、TiC、CrB 2 Composed of a variety of composite hard phases, this in-situ formed complex phase metal ceramic material has excellent high-temperature wear resistance and resistance to molten metal erosion, and has a low thermal expansion coefficient, which fully meets the working requirements of the die-casting machine punch. In production applications, it greatly improves the service life of the punch, effectively reduces costs, improves production efficiency and ensures the stability of the quality of die-casting products.

[0024] (2) The high-temperature wear-resistant coating on the punch surface prepared by the present invention is composed of a self-fluxing alloy, and its thermal expansion coefficient is similar to that of steel materials. It can achieve metallurgical bonding with the steel substrate to ensure the bonding strength between the coating and the substrate, and can avoid the problem of coating peeling caused by thermal alternating stress during use. The coating can self-deoxidize and slag during the deposition process, avoiding defects such as holes and cracks at the interface between the substrate and the coating.

[0025] (3) The cladding structure die-casting machine punch prepared by the present invention is deposited on the surface of common substrates such as cast iron, carbon steel or alloy steel. Its surface hardness reaches HRC64 or above and can be adjusted according to the working conditions. It can prepare a die-casting machine punch with a wear-resistant and corrosion-resistant surface and a core that is sufficiently strong and tough, saving raw materials and greatly improving the service life of the punch.

[0026] (4) The coating structure die-casting machine punch and its preparation method provided by the present invention only perform the deposition preparation of the high-temperature wear-resistant coating on the front end of the punch. The process is simple and the preparation cost of the workpiece is greatly reduced. It can be widely used in die-casting machines under high-temperature wear conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A cross-sectional view of a die-casting machine punch with a cladding structure provided by an embodiment of the present invention; Figure 2 A microstructure diagram of the interface between the surface coating and the substrate of a coating structure die-casting machine punch provided in Example 2 of the present invention; Among them, 1-substrate; 2-high temperature wear-resistant coating. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0030] See also Figure 1 The embodiment of the present invention provides a die-casting machine punch with a coating structure, comprising: a substrate 1, and a high-temperature wear-resistant coating 2 disposed on the outer surface of the front end of the substrate by cladding. The high-temperature wear-resistant coating has a thickness of 1-5 mm and a width of 10-30 mm.

[0031] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.

[0032] In each embodiment of the present invention, the material of the punch base and the raw material composition (weight percentage) of the high temperature wear-resistant coating are shown in Table 1 below: Table 1

[0033] Example 1 This embodiment provides a die-casting machine punch with a coating structure, comprising a substrate 1 and a high-temperature wear-resistant coating 2 , wherein the high-temperature wear-resistant coating 2 is arranged on the outer surface of the substrate 1 .

[0034] The substrate 1 is 42CrMo alloy steel; The raw material composition of the high temperature wear-resistant coating 2 includes, by weight percentage: Mo: 20%, Cr: 15%, Zr: 2%, Co: 10%, Si: 1.5%, C: 2%, B: 2%, Ti: 2%, and the balance is Fe.

[0035] The method for preparing the cladding structure die-casting machine punch comprises the following steps: Step 1: Obtain a substrate, machine a punch blank, place the punch blank in a heating furnace, preheat the punch blank to 250° C., and keep it warm for 2.5 hours; Step 2: Take the raw material powder of the high temperature wear-resistant coating, place it in a mixing device, mix it for 2.5 hours, and obtain the cladding powder; dry the cladding powder, then put it into the outer skin, draw it, and obtain the flux-cored welding wire, the outer skin of which is ordinary low-carbon steel; Step 3: The flux-cored welding wire prepared in step 2 is clad on the outer surface of the front end of the preheated punch blank by submerged arc welding (current is 500A, voltage is 34V, and cladding speed is 60mm / min), with a cladding thickness of 5mm and a cladding width of 10mm; Step 4: Finish the clad punch to the specified size, and store the finished product in warehouse.

[0036] In this embodiment, the punch prepared is deposited on the surface of the alloy quenched and tempered steel substrate. The thermal expansion coefficient of the prepared punch surface coating is close to that of the alloy quenched and tempered steel, and can be metallurgically bonded with the steel substrate. The surface hardness reaches HRC64.5, and the surface layer is wear-resistant and resistant to metal liquid corrosion under high temperature conditions, which greatly improves the service life of the punch in production applications. At the same time, since only the front end of the punch is deposited, the preparation cost of the workpiece is effectively reduced and the production efficiency is improved.

[0037] Example 2 This embodiment provides a die-casting machine punch with a coating structure, comprising a substrate 1 and a high-temperature wear-resistant coating 2 , wherein the high-temperature wear-resistant coating 2 is arranged on the outer surface of the substrate 1 .

[0038] The substrate 1 is 45 steel; The raw material composition of the high temperature wear-resistant coating 2 includes, by weight percentage: Mo: 25%, Cr: 12%, Zr: 5%, Co: 5%, Si: 2.0%, C: 4%, B: 1.5%, Ti: 5%, and the balance is Fe.

[0039] The method for preparing the cladding structure die-casting machine punch comprises the following steps: Step 1: Obtain a substrate, machine a punch blank, place the punch blank in a heating furnace, preheat the punch blank to 300° C., and keep it warm for 2 hours; Step 2: Take the raw material powder of the high temperature wear-resistant coating, place it in a mixing device, mix it for 3 hours, and obtain the cladding powder; dry the cladding powder, then put it into the outer skin, draw it, and obtain the flux-cored welding wire, the outer skin of which is stainless steel; Step 3: The flux-cored welding wire prepared in step 2 is clad on the outer surface of the front end of the preheated punch blank by an argon arc cladding process (current is 300A, voltage is 26V, and cladding speed is 30mm / min) to obtain a cladding layer, with a cladding thickness of 3mm and a cladding width of 20mm; Step 4: Finish the clad punch to the specified size, and store the finished product in warehouse.

[0040] In this embodiment, the punch prepared is deposited on the surface of the carbon steel substrate. The thermal expansion coefficient of the surface coating of the punch prepared is close to that of carbon steel, and can be metallurgically bonded with the steel substrate. The surface hardness reaches HRC66.2, which is wear-resistant and resistant to metal liquid corrosion under high temperature conditions, and greatly improves the service life of the punch in production applications. At the same time, since only the front end of the punch is deposited, the preparation cost of the workpiece is effectively reduced and the production efficiency is improved.

[0041] Example 3 This embodiment provides a die-casting machine punch with a coating structure, comprising a substrate 1 and a high-temperature wear-resistant coating 2 , wherein the high-temperature wear-resistant coating 2 is arranged on the outer surface of the substrate 1 .

[0042] The substrate 1 is QT600 ductile iron; The raw material composition of the high temperature wear-resistant coating 2 includes, by weight percentage: Mo: 23%, Cr: 10%, Zr: 3%, Co: 8%, Si: 2.5%, C: 3%, B: 2.5%, Ti: 3%, and the balance is Fe.

[0043] The method for preparing the cladding structure die-casting machine punch comprises the following steps: Step 1: Obtain a substrate, machine a punch blank, place the punch blank in a heating furnace, preheat the punch blank to 200° C., and keep it warm for 3 hours; Step 2: Take the raw material powder of the high temperature wear-resistant coating, place it in a mixing device, mix it for 3 hours, and obtain the cladding powder; dry the cladding powder, then put it into the outer skin, draw it, and obtain the flux-cored welding wire, the outer skin of which is stainless steel; Step 3: The flux-cored welding wire prepared in step 2 is clad on the outer surface of the front end of the preheated punch blank by plasma cladding (current is 300A, voltage is 52V, cladding speed is 40mm / min), the cladding thickness is 5mm, and the cladding width is 15mm; Step 4: Finish the clad punch to the specified size, and store the finished product in warehouse.

[0044] In this embodiment, the punch prepared is deposited on the surface of the cast iron substrate. The thermal expansion coefficient of the prepared punch surface coating is close to that of cast iron, and can be metallurgically bonded with the cast iron substrate. The surface hardness reaches HRC65.8, which is wear-resistant and resistant to molten metal corrosion under high temperature conditions, and greatly improves the service life of the punch in production applications. At the same time, since only the front end of the punch is deposited, the preparation cost of the workpiece is effectively reduced and the production efficiency is improved.

[0045] Example 4 This embodiment provides a die-casting machine punch with a coating structure, comprising a substrate 1 and a high-temperature wear-resistant coating 2 , wherein the high-temperature wear-resistant coating 2 is arranged on the outer surface of the substrate 1 .

[0046] The substrate 1 is GCr15 alloy steel; The raw material composition of the high temperature wear-resistant coating 2 includes, by weight percentage: Mo: 20%, Cr: 13%, Zr: 3%, Co: 8%, Si: 2.5%, C: 2%, B: 3%, Ti: 5%, and the balance is Fe.

[0047] The method for preparing the cladding structure die-casting machine punch comprises the following steps: Step 1: Obtain a substrate, machine a punch blank, place the punch blank in a heating furnace, preheat the punch blank to 200°C, and keep it warm for 2.5 hours; Step 2: Take the raw material powder of the high temperature wear-resistant coating, place it in a mixing device, mix it for 2.5 hours, and obtain the cladding powder; dry the cladding powder, then put it into the outer skin, draw it, and obtain the flux-cored welding wire, the outer skin of which is ordinary low-carbon steel; Step 3: The flux-cored welding wire prepared in step 2 is clad on the outer surface of the front end of the preheated punch blank by an argon arc cladding process (current is 280A, voltage is 28V, and cladding speed is 35mm / min), with a cladding thickness of 2mm and a cladding width of 30mm; Step 4: Finish the clad punch to the specified size, and store the finished product in warehouse.

[0048] In this embodiment, the punch prepared is deposited on the surface of the alloy steel substrate. The thermal expansion coefficient of the surface coating of the punch prepared is close to that of the alloy steel, and can be metallurgically bonded with the steel substrate. The surface hardness reaches HRC65.7, and the surface layer is wear-resistant and resistant to metal liquid corrosion under high temperature conditions, which greatly improves the service life of the punch in production applications. At the same time, since only the front end of the punch is deposited, the preparation cost of the workpiece is effectively reduced and the production efficiency is improved.

[0049] Application performance testing Figure 2 This is a microscopic metallographic structure diagram of the surface coating and the substrate interface of the coating structure die-casting machine punch provided in Example 2 of the present invention. Figure 2 It can be seen that the substrate is well combined with the high temperature wear-resistant coating, and there are no defects such as holes and cracks. The relevant performance test results of the coating structure die-casting machine punches prepared in various embodiments of the present invention are shown in Table 2 below: Table 2

[0050] As can be seen from the above table, The present invention prepares a high temperature wear-resistant coating on the punch surface, which can not only significantly improve the surface hardness of the front end of the punch, but also has a thermal expansion coefficient of 8.96×10 -6 to 9.32×10-6 m / K, which is similar to that of steel materials. It can achieve metallurgical bonding with the steel matrix, ensure the bonding strength between the coating and the matrix, and avoid the problem of coating peeling caused by thermal alternating stress during use. Furthermore, the provision of a high-temperature wear-resistant coating can greatly increase the service life of the punch. Compared with the service life of a punch made of conventional materials, which is about 3,000 mold times, the service life of the punch with a high-temperature wear-resistant coating prepared by the present invention is as high as 28,000-33,100 mold times. The high-temperature wear-resistant coating is only prepared by deposition on the front end of the punch. The process is simple, which greatly reduces the preparation cost and use cost of the workpiece and can be widely used in die-casting machines under high-temperature wear conditions.

[0051] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of the specification of the present invention should be included in the protection scope of the present invention.

Claims

1. A die-casting machine punch with a cladding structure, characterized in that: include: A substrate, and a high-temperature wear-resistant coating disposed on the outer surface of the front end of the substrate in a cladding manner; The raw material composition of the high temperature wear-resistant coating includes, by weight percentage: Mo: 20%-25%, Cr: 10%-15%, Zr: 2%-5%, Co: 5%-10%, Si: 1.5%-2.5%, C: 2%-4%, B: 1.5%-3%, Ti: 2%-5%, and the balance is Fe.

2. The cladding structure die-casting machine punch according to claim 1, characterized in that: The material of the substrate includes one of cast iron, carbon steel and alloy steel.

3. The cladding structure die-casting machine punch according to claim 1, characterized in that: The high temperature wear-resistant coating has a thickness of 1-5 mm and a width of 10-30 mm.

4. The method for preparing a die-casting machine punch with a cladding structure according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, preparing a punch blank, and preheating and heat-insulating the punch blank; S2, mixing the raw materials of the high temperature wear-resistant coating to obtain the cladding powder, drying it, then filling it with an outer skin, and drawing it to obtain a flux-cored welding wire; S3, forming a high-temperature wear-resistant coating on the outer surface of the front end of the preheated punch blank by cladding the flux-cored welding wire; S4. Finish-process the clad punch to a specified size to obtain a clad structure die-casting machine punch.

5. The preparation method according to claim 4, characterized in that: In step S1, the preheating temperature of the punch blank is 200-300°C, and the insulation time is 2-3h.

6. The preparation method according to claim 4, characterized in that In step S2, the raw materials of the high temperature wear-resistant coating are all in powder form, with a particle size of 25-150 μm.

7. The preparation method according to claim 4, characterized in that: In step S2, the mixing is performed using a mixing device, and the mixing time is 2-3 hours.

8. The preparation method according to claim 4, characterized in that In step S2, the outer sheath of the flux-cored welding wire is low carbon steel or stainless steel, and the diameter of the flux-cored welding wire is 2.0-4.0 mm.

9. The preparation method according to claim 4, characterized in that: In step S3, the cladding method includes one or more combinations of plasma cladding, argon arc cladding, and submerged arc welding.

10. A die casting machine, characterized in that: It comprises a die-casting machine punch with a cladding structure according to any one of claims 1-3, or a die-casting machine punch with a cladding structure made by the preparation method according to any one of claims 4-9.

Images