Aluminum casting surface polishing process

Abstract

The invention relates to the technical field of aluminum casting treatment, and discloses an aluminum casting surface polishing process which comprises the following steps: (1) cleaning; (2) preparing pre-polishing treatment; (3) preheating treatment; (4) secondary polishing treatment; (5) cleaning and inspecting; through surface treatment of the green casting part, the roughness of the surface of the aluminum casting part can be greatly reduced, and the surface quality of the aluminum casting part is obviously improved. According to the aluminum casting surface polishing method, the aluminum casting is cleaned through the cleaning liquid before polishing treatment, stains on the surface of the aluminum casting can be effectively removed, and therefore the situation that the stains on the surface of the aluminum casting cover the follow-up polishing, and consequently the surface quality of the polished aluminum casting is not uniform is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum casting processing, in particular to a surface polishing process for an aluminum casting. Background Art

[0002] Aluminum castings are pure aluminum or aluminum alloy equipment parts obtained through the casting process. This processing method usually involves pouring heated liquid aluminum or aluminum alloy into a sand mold or metal mold, and then cooling it to form parts of various shapes and sizes. Aluminum castings are widely used in many fields due to their unique properties.

[0003] The main features and advantages of aluminum castings include the following: 1. Excellent mechanical properties, 2. Strong corrosion resistance, 3. Good thermal conductivity, 4. Lightweight, 5. High aesthetics.

[0004] Aluminum castings have a wide range of applications. Since aluminum castings are obtained through a casting process, their surface roughness is relatively high, which will produce a variety of negative effects during the application process. Therefore, it is necessary to perform certain surface treatments to reduce the surface roughness of aluminum castings.

[0005] Based on this, the present invention provides a surface polishing process for aluminum castings to solve the corresponding problems and further improve the surface hardness of the recycled aluminum alloy. Summary of the invention

[0006] In view of the problems in the prior art, the present invention provides a surface polishing process for aluminum castings.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a surface polishing process of an aluminum casting, comprising the following steps:

[0008] (1) Cleaning:

[0009] Add the aluminum casting into the cleaning solution, clean it, then take it out, put it in a drying oven to dry it for 40-50 minutes, and take it out;

[0010] (2) Preparation of pre-polishing treatment:

[0011] The dried aluminum casting is pre-polished in the pre-treatment polishing liquid for 5-6 minutes;

[0012] (3) Preheating treatment:

[0013] The pre-polished aluminum casting is first cleaned with clean water, then dried with nitrogen, heated to 400-450℃, kept warm for 1 hour, and then cooled to room temperature;

[0014] (4) Secondary polishing:

[0015] Adjust the composition of the pre-treatment polishing liquid, and then perform a secondary polishing treatment for 3-4 minutes on the aluminum casting after preheating treatment;

[0016] (5) Cleaning and inspection:

[0017] The aluminum castings after secondary polishing are cleaned and then placed in a drying oven for drying;

[0018] The dried aluminum castings are inspected and packaged after passing the polishing process.

[0019] As a further technical solution: in step (1), the cleaning solution is a mixture of sodium hydroxide, sodium carbonate, glycerol and water;

[0020] Among them, the mass fraction of sodium hydroxide is 5%;

[0021] The mass fraction of sodium carbonate is 10%;

[0022] The mass fraction of glycerol is 10%.

[0023] As a further technical solution: in step (1), the cleaning is firstly soaked in a cleaning solution for 30 minutes, then subjected to ultrasonic treatment for 10 minutes, and then taken out to complete the cleaning;

[0024] The soaking temperature is 60℃;

[0025] The ultrasonic frequency is 40kHz.

[0026] As a further technical solution: the pretreatment polishing liquid in step (2) comprises the following ingredients by weight: 3 parts of sodium dodecylbenzene sulfonate, 1.8 parts of ammonium molybdate, 3-5 parts of phosphoric acid, 6-8 parts of hydrogen peroxide, 3-4 parts of sulfuric acid, 1.2 parts of tartaric acid, and 80 parts of deionized water.

[0027] As a further technical solution: the polishing pressure of the pre-polishing treatment is: 0.85 kPa;

[0028] The polishing liquid flow rate was 18 mL / min;

[0029] The polishing head speed is 55r / min;

[0030] The polishing disc speed is 120r / min.

[0031] As a further technical solution: the heating rate of the preheating treatment in step (3) is 10°C / min.

[0032] As a further technical solution: in step (4), the composition of the pre-treatment polishing liquid is adjusted to:

[0033] Based on the total mass of the pretreatment polishing liquid, 1-1.5% of aluminum oxide abrasive grains and 3-4% of nitric acid are added to the pretreatment polishing liquid.

[0034] As a further technical solution: the polishing pressure of the secondary polishing process is: 1.2 kPa;

[0035] The polishing liquid flow rate was 25 mL / min;

[0036] The polishing head speed is 70r / min;

[0037] The polishing disc speed is 150r / min.

[0038] As a further technical solution: in step (5), the drying time in the drying oven is 4 hours;

[0039] The drying temperature is 100°C.

[0040] Beneficial effects of the present invention:

[0041] The present invention can significantly reduce the surface roughness of the aluminum casting by treating the surface of the green casting, and significantly improve the surface quality of the aluminum casting.

[0042] By cleaning the aluminum casting with a cleaning liquid before polishing, the stains on the surface of the aluminum casting can be effectively removed, thereby avoiding the stains on the surface of the aluminum casting from covering the subsequent polishing and causing uneven surface quality of the aluminum casting after polishing.

[0043] The present invention performs a pre-polishing treatment on the surface of the aluminum casting, and the purpose is to perform a preliminary polishing treatment on the surface of the aluminum casting. During the polishing process, the pre-treatment polishing solution will form different film layers or replacement layers at the microscopic concave and convex parts of the surface of the aluminum casting. Since the current is concentrated and the activity is large on the convex surface, the formation of its film layer is relatively delayed and thin, while the concave surface preferentially forms a thicker film layer. The difference in the speed of film layer formation leads to a difference in dissolution rate, that is, the convex part dissolves faster due to the thin film layer, and the concave surface dissolves slower due to the thick film layer. Through this corrosion rate difference, the leveling effect on the surface of the aluminum alloy is achieved; by controlling the composition and conditions of the pre-treatment polishing solution, the convex parts of the surface can be dissolved more preferentially than the concave parts, thereby achieving the purpose of surface flattening. After a subsequent secondary polishing treatment, the surface of the aluminum casting can be further polished and flattened on the basis of the pre-treatment polishing, further reducing the surface roughness of the aluminum casting and improving the surface quality of the aluminum casting.

[0044] The comprehensive treatment of the present invention can not only improve the surface finish and smoothness of the aluminum casting, but also eliminate mechanical lines and defects; on the basis of improving the surface quality of the aluminum casting, the corrosion resistance is further enhanced and the service life of the product is extended. DETAILED DESCRIPTION

[0045] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application.

[0046] The polishing equipment used in the embodiment is an automatic pressure grinding and polishing machine (model UNIPOL-1200S, Shenyang Kejing Automation Equipment Co., Ltd.).

[0047] The average particle size of aluminum oxide abrasive is (20nm).

[0048] Example 1

[0049] A surface polishing process for an aluminum casting comprises the following steps:

[0050] (1) Cleaning:

[0051] The aluminum casting is added to the cleaning liquid for cleaning, then taken out, placed in a drying oven for drying for 40 minutes, and then taken out; the cleaning liquid is a mixture of sodium hydroxide, sodium carbonate, glycerin, and water;

[0052] Among them, the mass fraction of sodium hydroxide is 5%;

[0053] The mass fraction of sodium carbonate is 10%;

[0054] The mass fraction of glycerol is 10%.

[0055] The cleaning is to soak in the cleaning solution for 30 minutes, then perform ultrasonic treatment for 10 minutes, take out, and complete the cleaning;

[0056] The soaking temperature is 60℃;

[0057] The ultrasonic frequency is 40kHz.

[0058] (2) Preparation of pre-polishing treatment:

[0059] The dried aluminum casting was pre-polished in the presence of a pre-treatment polishing liquid for 5 minutes; the pre-treatment polishing liquid included the following ingredients by weight: 3 parts of sodium dodecylbenzene sulfonate, 1.8 parts of ammonium molybdate, 3 parts of phosphoric acid, 6 parts of hydrogen peroxide, 3 parts of sulfuric acid, 1.2 parts of tartaric acid, and 80 parts of deionized water.

[0060] The polishing pressure of the pre-polishing treatment is: 0.85kPa;

[0061] The polishing liquid flow rate was 18 mL / min;

[0062] The polishing head speed is 55r / min;

[0063] The polishing disc speed is 120r / min.

[0064] (3) Preheating treatment:

[0065] The pre-polished aluminum casting was first cleaned with clean water, then dried with nitrogen, heated to 400°C, kept warm for 1 hour, and then cooled to room temperature; the heating rate of the preheating treatment was 10°C / min.

[0066] (4) Secondary polishing:

[0067] Adjust the composition of the pre-treatment polishing liquid, and then perform a secondary polishing treatment for 3 minutes on the aluminum casting after the preheating treatment;

[0068] Adjust the composition of the pretreatment polishing liquid to:

[0069] Based on the total mass of the pretreatment polishing liquid, 1% of aluminum oxide abrasive grains and 3% of nitric acid were added to the pretreatment polishing liquid.

[0070] The polishing pressure of the secondary polishing treatment is: 1.2kPa;

[0071] The polishing liquid flow rate was 25 mL / min;

[0072] The polishing head speed is 70r / min;

[0073] The polishing disc speed is 150r / min.

[0074] (5) Cleaning and inspection:

[0075] The aluminum castings after secondary polishing are cleaned and then placed in a drying oven for drying;

[0076] The aluminum castings after drying are inspected and packaged after passing the inspection, completing the entire polishing process; the drying time in the drying oven is 4 hours;

[0077] The drying temperature is 100°C.

[0078] Example 2

[0079] A surface polishing process for an aluminum casting comprises the following steps:

[0080] (1) Cleaning:

[0081] The aluminum casting is added to the cleaning liquid for cleaning, then taken out, placed in a drying oven for drying for 45 minutes, and then taken out; the cleaning liquid is a mixture of sodium hydroxide, sodium carbonate, glycerin, and water;

[0082] Among them, the mass fraction of sodium hydroxide is 5%;

[0083] The mass fraction of sodium carbonate is 10%;

[0084] The mass fraction of glycerol is 10%.

[0085] The cleaning is to soak in the cleaning solution for 30 minutes, then perform ultrasonic treatment for 10 minutes, take out, and complete the cleaning;

[0086] The soaking temperature is 60℃;

[0087] The ultrasonic frequency is 40kHz.

[0088] (2) Preparation of pre-polishing treatment:

[0089] The dried aluminum casting is pre-polished in the presence of a pre-treatment polishing liquid for 5-6 minutes; the pre-treatment polishing liquid comprises the following components by weight: 3 parts of sodium dodecylbenzene sulfonate, 1.8 parts of ammonium molybdate, 3.5 parts of phosphoric acid, 6.2 parts of hydrogen peroxide, 3.5 parts of sulfuric acid, 1.2 parts of tartaric acid, and 80 parts of deionized water.

[0090] The polishing pressure of the pre-polishing treatment is: 0.85kPa;

[0091] The polishing liquid flow rate was 18 mL / min;

[0092] The polishing head speed is 55r / min;

[0093] The polishing disc speed is 120r / min.

[0094] (3) Preheating treatment:

[0095] The pre-polished aluminum casting was first cleaned with clean water, then the surface was blown dry with nitrogen, and then heated to 420°C, kept warm for 1 hour, and then cooled to room temperature; the heating rate of the preheating treatment was 10°C / min.

[0096] (4) Secondary polishing:

[0097] The composition of the pre-treatment polishing liquid was adjusted, and then the aluminum castings after the pre-heat treatment were subjected to secondary polishing for 3.5 minutes;

[0098] Adjust the composition of the pretreatment polishing liquid to:

[0099] Based on the total mass of the pretreatment polishing liquid, 1.2% of aluminum oxide abrasive grains and 3.4% of nitric acid were added to the pretreatment polishing liquid.

[0100] The polishing pressure of the secondary polishing treatment is: 1.2kPa;

[0101] The polishing liquid flow rate was 25 mL / min;

[0102] The polishing head speed is 70r / min;

[0103] The polishing disc speed is 150r / min.

[0104] (5) Cleaning and inspection:

[0105] The aluminum castings after secondary polishing are cleaned and then placed in a drying oven for drying;

[0106] The aluminum castings after drying are inspected and packaged after passing the inspection, completing the entire polishing process; the drying time in the drying oven is 4 hours;

[0107] The drying temperature is 100°C.

[0108] Example 3

[0109] A surface polishing process for an aluminum casting comprises the following steps:

[0110] (1) Cleaning:

[0111] The aluminum casting is added to the cleaning liquid for cleaning, then taken out, placed in a drying oven for drying for 45 minutes, and then taken out; the cleaning liquid is a mixture of sodium hydroxide, sodium carbonate, glycerin, and water;

[0112] Among them, the mass fraction of sodium hydroxide is 5%;

[0113] The mass fraction of sodium carbonate is 10%;

[0114] The mass fraction of glycerol is 10%.

[0115] The cleaning is to soak in the cleaning solution for 30 minutes, then perform ultrasonic treatment for 10 minutes, take out, and complete the cleaning;

[0116] The soaking temperature is 60℃;

[0117] The ultrasonic frequency is 40kHz.

[0118] (2) Preparation of pre-polishing treatment:

[0119] The dried aluminum casting was pre-polished in the presence of a pre-treatment polishing liquid for 5.5 minutes; the pre-treatment polishing liquid included the following ingredients by weight: 3 parts of sodium dodecylbenzene sulfonate, 1.8 parts of ammonium molybdate, 4 parts of phosphoric acid, 7 parts of hydrogen peroxide, 3.8 parts of sulfuric acid, 1.2 parts of tartaric acid, and 80 parts of deionized water.

[0120] The polishing pressure of the pre-polishing treatment is: 0.85kPa;

[0121] The polishing liquid flow rate was 18 mL / min;

[0122] The polishing head speed is 55r / min;

[0123] The polishing disc speed is 120r / min.

[0124] (3) Preheating treatment:

[0125] The pre-polished aluminum casting was first cleaned with clean water, then the surface was blown dry with nitrogen, and then heated to 430°C, kept warm for 1 hour, and then cooled to room temperature; the heating rate of the preheating treatment was 10°C / min.

[0126] (4) Secondary polishing:

[0127] The composition of the pre-treatment polishing liquid was adjusted, and then the aluminum castings after the pre-heat treatment were subjected to secondary polishing for 3.6 minutes;

[0128] Adjust the composition of the pretreatment polishing liquid to:

[0129] Based on the total mass of the pretreatment polishing liquid, 1.2% of aluminum oxide abrasive grains and 3.5% of nitric acid were added to the pretreatment polishing liquid.

[0130] The polishing pressure of the secondary polishing treatment is: 1.2kPa;

[0131] The polishing liquid flow rate was 25 mL / min;

[0132] The polishing head speed is 70r / min;

[0133] The polishing disc speed is 150r / min.

[0134] (5) Cleaning and inspection:

[0135] The aluminum castings after secondary polishing are cleaned and then placed in a drying oven for drying;

[0136] The aluminum castings after drying are inspected and packaged after passing the inspection, completing the entire polishing process; the drying time in the drying oven is 4 hours;

[0137] The drying temperature is 100°C.

[0138] Example 4

[0139] A surface polishing process for an aluminum casting comprises the following steps:

[0140] (1) Cleaning:

[0141] The aluminum casting is added to the cleaning liquid for cleaning, then taken out, placed in a drying oven for drying for 45 minutes, and then taken out; the cleaning liquid is a mixture of sodium hydroxide, sodium carbonate, glycerin, and water;

[0142] Among them, the mass fraction of sodium hydroxide is 5%;

[0143] The mass fraction of sodium carbonate is 10%;

[0144] The mass fraction of glycerol is 10%.

[0145] The cleaning is to soak in the cleaning solution for 30 minutes, then perform ultrasonic treatment for 10 minutes, take out, and complete the cleaning;

[0146] The soaking temperature is 60℃;

[0147] The ultrasonic frequency is 40kHz.

[0148] (2) Preparation of pre-polishing treatment:

[0149] The dried aluminum casting was pre-polished in the presence of a pre-treatment polishing liquid for 5.8 minutes; the pre-treatment polishing liquid included the following ingredients by weight: 3 parts of sodium dodecylbenzene sulfonate, 1.8 parts of ammonium molybdate, 4.5 parts of phosphoric acid, 6.5 parts of hydrogen peroxide, 3.5 parts of sulfuric acid, 1.2 parts of tartaric acid, and 80 parts of deionized water.

[0150] The polishing pressure of the pre-polishing treatment is: 0.85kPa;

[0151] The polishing liquid flow rate was 18 mL / min;

[0152] The polishing head speed is 55r / min;

[0153] The polishing disc speed is 120r / min.

[0154] (3) Preheating treatment:

[0155] The pre-polished aluminum casting was first cleaned with clean water, then the surface was blown dry with nitrogen, and then heated to 440°C, kept warm for 1 hour, and then cooled to room temperature; the heating rate of the preheating treatment was 10°C / min.

[0156] (4) Secondary polishing:

[0157] The composition of the pre-treatment polishing liquid was adjusted, and then the aluminum castings after the pre-heat treatment were subjected to secondary polishing for 3.2 minutes;

[0158] Adjust the composition of the pretreatment polishing liquid to:

[0159] Based on the total mass of the pretreatment polishing liquid, 1.4% of aluminum oxide abrasive grains and 3.6% of nitric acid were added to the pretreatment polishing liquid.

[0160] The polishing pressure of the secondary polishing treatment is: 1.2kPa;

[0161] The polishing liquid flow rate was 25 mL / min;

[0162] The polishing head speed is 70r / min;

[0163] The polishing disc speed is 150r / min.

[0164] (5) Cleaning and inspection:

[0165] The aluminum castings after secondary polishing are cleaned and then placed in a drying oven for drying;

[0166] The aluminum castings after drying are inspected and packaged after passing the inspection, completing the entire polishing process; the drying time in the drying oven is 4 hours;

[0167] The drying temperature is 100°C.

[0168] Example 5

[0169] A surface polishing process for an aluminum casting comprises the following steps:

[0170] (1) Cleaning:

[0171] The aluminum casting is added to the cleaning liquid for cleaning, then taken out, placed in a drying oven for drying for 50 minutes, and then taken out; the cleaning liquid is a mixture of sodium hydroxide, sodium carbonate, glycerin, and water;

[0172] Among them, the mass fraction of sodium hydroxide is 5%;

[0173] The mass fraction of sodium carbonate is 10%;

[0174] The mass fraction of glycerol is 10%.

[0175] The cleaning is to soak in the cleaning solution for 30 minutes, then perform ultrasonic treatment for 10 minutes, take out, and complete the cleaning;

[0176] The soaking temperature is 60℃;

[0177] The ultrasonic frequency is 40kHz.

[0178] (2) Preparation of pre-polishing treatment:

[0179] The dried aluminum casting was pre-polished in the presence of a pre-treatment polishing liquid for 6 minutes; the pre-treatment polishing liquid included the following components by weight: 3 parts of sodium dodecylbenzene sulfonate, 1.8 parts of ammonium molybdate, 5 parts of phosphoric acid, 8 parts of hydrogen peroxide, 4 parts of sulfuric acid, 1.2 parts of tartaric acid, and 80 parts of deionized water.

[0180] The polishing pressure of the pre-polishing treatment is: 0.85kPa;

[0181] The polishing liquid flow rate was 18 mL / min;

[0182] The polishing head speed is 55r / min;

[0183] The polishing disc speed is 120r / min.

[0184] (3) Preheating treatment:

[0185] The pre-polished aluminum casting was first cleaned with clean water, then the surface was blown dry with nitrogen, and then heated to 450°C, kept warm for 1 hour, and then cooled to room temperature; the heating rate of the preheating treatment was 10°C / min.

[0186] (4) Secondary polishing:

[0187] The composition of the pre-treatment polishing liquid was adjusted, and then the aluminum castings after the pre-heat treatment were subjected to secondary polishing for 4 minutes;

[0188] Adjust the composition of the pretreatment polishing liquid to:

[0189] Based on the total mass of the pretreatment polishing liquid, 1.5% of aluminum oxide abrasive grains and 4% of nitric acid were added to the pretreatment polishing liquid.

[0190] The polishing pressure of the secondary polishing treatment is: 1.2kPa;

[0191] The polishing liquid flow rate was 25 mL / min;

[0192] The polishing head speed is 70r / min;

[0193] The polishing disc speed is 150r / min.

[0194] (5) Cleaning and inspection:

[0195] The aluminum castings after secondary polishing are cleaned and then placed in a drying oven for drying;

[0196] The aluminum castings after drying are inspected and packaged after passing the inspection, completing the entire polishing process; the drying time in the drying oven is 4 hours;

[0197] The drying temperature is 100°C.

[0198] Comparative Example 1:

[0199] On the basis of Example 1, only the pre-polishing process is performed, and the rest of the technical solutions remain unchanged.

[0200] Comparative Example 2:

[0201] On the basis of Example 1, only a secondary polishing process is performed, and the rest of the technical solutions remain unchanged.

[0202] test

[0203] The parameters of the experimental aluminum castings are:

[0204] Table 1

[0205] Mass fraction % Cu 4.1 Mg 1.5 Mn 0.7 Fe 0.5 Si 0.25 Zn 0.12 Ti 0.10 Cr 0.10 Al margin

[0206] The samples were randomly divided into 7 groups, each of which was treated by the process of the embodiment and the comparative example, and the surface roughness of each group was compared;

[0207] Table 2

[0208]

[0209]

[0210] It can be seen from Table 2 that after being processed by the process of the present invention, the surface roughness of the aluminum casting can be greatly reduced.

[0211] Taking Example 1 as the basic sample, the effects of different secondary polishing treatment times on the surface roughness of aluminum castings were compared;

[0212] Table 3

[0213] Time / min Surface roughness Ranm 1 12.37 2 8.12 3 4.03 4 4.16 5 6.33 6 8.05

[0214] It can be seen from Table 3 that with the increase of the secondary polishing treatment time, the surface roughness of the aluminum casting first decreases and then gradually increases.

[0215] Taking Example 1 as the basic sample, the effects of different amounts of aluminum oxide abrasive addition on the surface roughness of aluminum castings are compared, as shown in Table 4;

[0216] Table 4

[0217]

[0218]

[0219] It can be seen from Table 4 that different amounts of alumina abrasive added will affect the surface roughness of aluminum alloy.

[0220] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A surface polishing process for aluminum castings, characterized in that: The following steps are involved: (1) Cleaning: Add the aluminum casting into the cleaning solution, clean it, then take it out, put it in a drying oven to dry it for 40-50 minutes, and take it out; (2) Preparation of pre-polishing treatment: The dried aluminum casting is pre-polished in the pre-treatment polishing liquid for 5-6 minutes; (3) Preheating treatment: The pre-polished aluminum casting is first cleaned with clean water, then dried with nitrogen, heated to 400-450℃, kept warm for 1 hour, and then cooled to room temperature; (4) Secondary polishing: Adjust the composition of the pre-treatment polishing liquid, and then perform a secondary polishing treatment for 3-4 minutes on the aluminum casting after preheating treatment; (5) Cleaning and inspection: The aluminum castings after secondary polishing are cleaned and then placed in a drying oven for drying; The dried aluminum castings are inspected and packaged after passing the polishing process.

2. The surface polishing process of an aluminum casting according to claim 1, characterized in that: In step (1), the cleaning solution is a mixture of sodium hydroxide, sodium carbonate, glycerol and water; Among them, the mass fraction of sodium hydroxide is 5%; The mass fraction of sodium carbonate is 10%; The mass fraction of glycerol is 10%.

3. The surface polishing process of an aluminum casting according to claim 2, characterized in that: The cleaning in step (1) is to first soak in a cleaning solution for 30 minutes, then perform ultrasonic treatment for 10 minutes, take out, and complete the cleaning; The soaking temperature is 60℃; The ultrasonic frequency is 40kHz.

4. The surface polishing process of an aluminum casting according to claim 3, characterized in that: The pretreatment polishing liquid in step (2) comprises the following ingredients by weight: 3 parts of sodium dodecylbenzene sulfonate, 1.8 parts of ammonium molybdate, 3-5 parts of phosphoric acid, 6-8 parts of hydrogen peroxide, 3-4 parts of sulfuric acid, 1.2 parts of tartaric acid, and 80 parts of deionized water.

5. The surface polishing process of aluminum casting according to claim 4, characterized in that: The polishing pressure of the pre-polishing treatment is: 0.85kPa; The polishing liquid flow rate was 18 mL / min; The polishing head speed is 55r / min; The polishing disc speed is 120r / min.

6. The surface polishing process of an aluminum casting according to claim 5, characterized in that: The heating rate of the preheating treatment in step (3) is 10°C / min.

7. The surface polishing process of aluminum casting according to claim 1, characterized in that: In step (4), the composition of the pre-treatment polishing liquid is adjusted to: Based on the total mass of the pretreatment polishing liquid, 1-1.5% of aluminum oxide abrasive grains and 3-4% of nitric acid are added to the pretreatment polishing liquid.

8. The surface polishing process of aluminum casting according to claim 7, characterized in that: The polishing pressure of the secondary polishing treatment is: 1.2kPa; The polishing liquid flow rate was 25 mL / min; The polishing head speed is 70r / min; The polishing disc speed is 150r / min.

9. The surface polishing process of aluminum casting according to claim 1, characterized in that: The drying time in the drying oven in step (5) is 4 hours; The drying temperature is 100°C.

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