A polishing method for improving the service life of an aluminum alloy die-casting mold

Abstract

The application discloses a polishing method for prolonging the service life of an aluminum alloy die-casting die, which comprises the following steps: polishing the die riser in multiple passes by using a polishing device in a way that the particle size of the polishing particles is from coarse to fine, and the final surface roughness is not higher than 0.3 microns; the polishing device comprises a coarse grinding device with a particle size of 200 meshes or less and a fine grinding device with a particle size of 1200 meshes or more; the depth of coarse grinding is not higher than 0.1 mm, and the depth of fine grinding is not higher than 0.05 mm; if the surface is still not smooth after coarse grinding and fine grinding, fine grinding is continuously performed until the surface is smooth; and the total polishing depth of coarse grinding and fine grinding is not higher than 0.2 mm. The die riser is polished to remove corrosion pits, micro-cracks and carburized layers, improve the flatness of the die riser, reduce stress concentration, and solve the problem that the die is prone to cracking, so that the service life of the die is prolonged. The application has the advantages of simple operation, high practicability, low use cost, significant prolongation of the service life of the die and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of die casting auxiliary equipment parts, and particularly relates to a polishing method for prolonging the service life of an aluminum alloy die casting die. BACKGROUND

[0002] Differential pressure casting is a process of using pressure to press melt (670-710 DEG C) into a mold cavity, and is an economical manufacturing method for aluminum alloy automobile parts. However, the mold is subjected to high pressure, high temperature, and chemical corrosion during service, and is prone to premature failure. The failure forms include thermal fatigue cracks, melt flow erosion, corrosion and welding of the aluminum liquid to the mold surface, deformation and serious fracture of the mold contact surface, and the like.

[0003] The mold cost accounts for about 8-15% of the total cost of producing aluminum die castings, and premature mold failure will increase the production cost. Therefore, how to prevent mold cracking and prolong the service life of the mold is of great significance to production efficiency and cost reduction. SUMMARY

[0004] To solve the above problems, the present application provides a polishing method for prolonging the service life of an aluminum alloy die casting die, which prolongs the service life of the aluminum alloy die by a simple and low-cost method.

[0005] According to one aspect of the present application, a polishing method for prolonging the service life of an aluminum alloy die casting die is provided, which comprises the following steps: using a polishing device to polish the mold riser in a manner of gradually decreasing the particle size from coarse to fine, and finally the surface roughness is not higher than 0.3 μm, the polishing device comprises: a coarse grinding device with a particle size of 200 mesh or less, a fine grinding device with a particle size of 1200 mesh or more, the depth of coarse grinding is not more than 0.1 mm, the depth of fine grinding is not more than 0.05 mm, if the surface is still not smooth, continue to fine grinding until the surface is smooth, and the total polishing depth of coarse grinding and fine grinding is not more than 0.2 mm.

[0006] Preferably, the total polishing depth of each time is 0.1-0.2 mm.

[0007] Preferably, the polishing method for prolonging the service life of the aluminum alloy die casting die is implemented at an interval of 8000-10000 die casting times.

[0008] Preferably, the coarse grinding is performed by using sandpaper or a grinding wheel with a particle size of 200 mesh to polish off the oxide layer, corrosion pits, and carburized layer at the mold riser.

[0009] Preferably, the fine grinding is performed on the mold riser after coarse grinding by using sandpaper or a grinding wheel with a particle size of 1200 mesh or more, and the grinding marks of coarse grinding are polished off.

[0010] Preferably, the hardness of the surface of the mold riser is tested by a portable hardness tester, if the hardness is higher than the hardness of the mold base, the decarburized layer is not completely removed, continue to polish the mold riser to be consistent with the hardness of the mold base.

[0011] Preferably, the total polishing depth is recorded each time, and the total polishing depth within the mold service period is not more than 2 mm.

[0012] Preferably, water or a fan is used for cooling during polishing.

[0013] Preferably, the polishing device uses sandpaper or a grinding wheel.

[0014] According to the polishing method of the application, the operation is simple, the service life of the aluminum alloy mold can be improved by 1.5 times, and the production cost is greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0015] Fig. 1 is a schematic diagram of the polishing method for improving the service life of an aluminum alloy die casting mold;

[0016] Fig. 2 is a longitudinal section metallographic diagram of a 10000 mold aluminum alloy mold riser;

[0017] Fig. 3 is a longitudinal section scanning diagram of a 10000 mold aluminum alloy mold riser. DETAILED DESCRIPTION

[0018] Exemplary embodiments of the present application are described in detail below with reference to the attached drawing figures. The exemplary embodiments described below and shown in the drawings are intended to teach the principles of the present application, with the understanding that the present application can be adapted or modified as can be desired for a number of different applications and environments. Accordingly, the protection sought for the present application is defined by the claims that follow, rather than the exemplary embodiments that are described below. Furthermore, the same reference numerals in different drawings represent the same or similar elements. The size of each part shown in the drawings can not be to scale, and the orientation of each part can be shown schematically. Orientation descriptions, such as longitudinal, and up, down, left, right, top, bottom, etc., are made with reference to the orientation or position shown in the drawings, and are used for the convenience of description and simplification of the description, and should not be construed as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present application. The description of each embodiment below emphasizes the differences between the embodiments, and the same or similar parts can be referred to each other, and for brevity, will not be repeated. The technical features in different embodiments can be freely combined to form more embodiments according to design needs. Any numerical range stated herein is intended to include all sub-ranges contained therein, and a numerical range expressed using "value A ~ value B" means a range including the end values A and B. Those skilled in the art can understand that the terms "first", "second", "step", etc. in the present application are only used to distinguish different steps, devices or modules, and do not represent any specific technical meaning, nor indicate a certain logical order between them. For example, steps two and three can be transposed or performed in parallel.

[0019] The application provides a polishing method for improving the service life of an aluminum alloy die-casting die. The use of the application improves the service life of the aluminum alloy die and reduces production costs.

[0020] Reference Figs. 1 to 3 The polishing method for improving the service life of an aluminum alloy die-casting die polishes the riser 2 of the aluminum alloy die 1 to remove micro-cracks, corrosion pits, oxide layers, and carburized layers that have emerged at the riser 2, thereby reducing stress concentration at the riser 2 and preventing the emergence and propagation of fatigue cracks.

[0021] The polishing frequency is set according to the actual use environment and use characteristics of the die. Generally, the die is polished once every 10,000 die cycles, for example, once every 8,000-10,000 die cycles to eliminate adverse effects, because the corrosion pit depth and carburized layer depth at this die cycle are less than 0.2 mm. For example, Fig. 2 The riser of the aluminum alloy die is shown to have a carburized layer less than 200 μm thick at 10,000 die cycles, Fig. 3The aluminum alloy die riser is shown to have a rust layer less than 54 μm thick at 10000 die cycles. Thus, the problem of die cracking can be solved by polishing the corrosion pits, micro-cracks, carburized layer, and rust layer (oxidation layer) at the die riser according to the present application, thereby increasing the service life of the die.

[0022] According to an embodiment of the present application, the polishing method comprises the following steps: polishing the die riser in multiple passes in a manner of coarse to fine particle size, and the polishing device used for this purpose comprises: a coarse grinding device with a particle size of 200 mesh or less, and a fine grinding device with a particle size of 1200 mesh or more.

[0023] For example, sandpaper or a grinding wheel with a particle size of 200 mesh is used for coarse grinding to polish the oxidation layer, corrosion pits, and carburized layer at the riser 2, and the polishing depth should not exceed 0.1 mm. The riser 2 after the above coarse grinding is fine ground using sandpaper or a grinding wheel with a particle size of 1200 mesh or more, and the grinding marks of the coarse grinding are polished to reduce the surface roughness. The fine grinding depth should not exceed 0.05 mm, and if the surface is still not smooth, the fine grinding is continued until the surface is smooth. The total polishing depth of the coarse grinding and the fine grinding should not exceed 0.2 mm, and preferably the total polishing depth of each pass is 0.1-0.2 mm. The surface hardness of the riser is tested using a portable hardness tester, and if the hardness is higher than the hardness of the die base, the decarburized layer is not completely removed, and the polishing is continued until the hardness is consistent with the hardness of the die base.

[0024] The polishing depth of each pass is recorded, and the total polishing depth during the service life of the die should not exceed 2 mm.

[0025] The final polished surface is smooth without pits and black spots, and the final surface roughness is not higher than 0.3 μm.

[0026] Cooling is performed during the polishing process using water or a fan, etc. to avoid overheating of the surface and affecting the microstructure of the surface.

[0027] The polishing device is not particularly limited, and appropriate polishing rollers, polishing belts, etc. such as sandpaper or grinding wheels can be selected according to the use scenario.

[0028] All other embodiments obtained by other persons in the art without creative labor based on the embodiments in the present application are within the scope of protection of the present application. The specific meanings of the above terms in the present application can be understood according to the specific circumstances by those of ordinary skill in the art. Although the present application has been described with reference to various specific embodiments, it should be understood that modifications can be made within the spirit and scope of the described inventive concept. Therefore, it is intended that the present application not be limited to the described embodiments, but rather have the full scope defined by the language of the appended claims.

Claims

1. A polishing method for improving the life of an aluminum alloy die casting mold, characterized by, It comprises the following steps: using polishing device to polish the mold riser in the way of rough to fine particle size, the final surface roughness is not higher than 0.3 μm, the polishing device comprises: coarse grinding device with particle size below 200 mesh, fine grinding device with particle size above 1200 mesh, the depth of coarse grinding is not more than 0.1 mm, the depth of fine grinding is not more than 0.05 mm, if it is still not polished smooth, continue to fine grinding until the surface is smooth, the total polishing depth of coarse grinding and fine grinding is not more than 0.2 mm, the total polishing depth of each time is 0.1-0.2 mm, the interval is 8000-10000 mold times, the sandpaper or grinding wheel with particle size below 200 mesh is used for coarse grinding to polish off the oxide layer, corrosion pit and carburized layer of the mold riser, the sandpaper or grinding wheel with particle size above 1200 mesh is used for fine grinding to the mold riser after coarse grinding, and the grinding marks of coarse grinding are polished off, the hardness of the mold riser surface is tested by using portable hardness tester, if the hardness is higher than the hardness of the mold base, the mold riser is continuously polished until the hardness is consistent with the hardness of the mold base, the total polishing depth of each time is recorded, and the total polishing depth in the mold using period is not more than 2 mm.

2. The polishing method for improving the life of an aluminum alloy die-casting mold according to claim 1, characterized by, Water or fan is used for cooling during polishing.

3. The honing method for improving the life of an aluminum alloy die-casting mold according to claim 1, characterized by, The polishing device adopts sandpaper or grinding wheel.

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