Vacuum pressure infiltration process for die casting

Abstract

The invention discloses a vacuum pressure infiltration process for a die casting. The vacuum pressure infiltration process comprises the following steps: S1, carrying out infiltration pretreatment; step S2, carrying out infiltration treatment; s3, laser cleaning is carried out; and step S4, treatment after infiltration. The die casting vacuum pressure infiltration process comprises the steps of infiltration pretreatment, infiltration treatment, laser cleaning and infiltration aftertreatment, the technological process is easy to operate, and laser cleaning surface treatment is conducted on a die casting after infiltration treatment; the problems of internal looseness and micropore defects of the die casting and difficulty in cleaning screw holes and process holes blocked by an impregnant in the impregnation process are solved, the service life of the die casting is effectively prolonged, the impregnation effect is good, and the impregnation yield is effectively improved.

Description

Technical Field

[0001] The invention relates to a die casting processing technology, more specifically, to a die casting vacuum pressure infiltration technology. Background Art

[0002] Die casting is a process that uses three major elements, namely, machines, molds and alloys, to unify pressure, speed and time. It is used for hot metal processing. The existence of pressure is the main feature of die casting that distinguishes it from other casting methods. Die casting is a special casting method with little cutting that has developed rapidly in modern metal processing technology. It is a process in which molten metal is filled into a mold under high pressure and high speed, and crystallized and solidified under high pressure to form a casting.

[0003] However, die castings may have defects such as looseness and micropores in the die casting process. Casting impregnation can prevent internal corrosion and prepare for surface treatments such as electroplating and painting. It can also be used as a remedial measure for looseness and micropores in castings. Impregnation is a micropore (fine crack) penetration sealing process, in which the sealing medium (usually a low-viscosity liquid) is infiltrated into the micropores (fine cracks) through natural penetration (i.e. micropore self-priming), vacuuming and pressurizing, etc., filling the cracks and then fixing the sealing medium in the cracks through natural (room temperature) cooling or heating to achieve the effect of sealing the cracks.

[0004] The disadvantages of the prior art are that: the die castings in the prior art have internal looseness and micropore defects during the infiltration process, and the screw holes and process holes are blocked by the infiltration agent during the infiltration process and are difficult to clean. Summary of the invention

[0005] Based on this, it is necessary to provide a vacuum pressure infiltration process for die castings to address the above technical problems.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: A vacuum pressure infiltration process for die castings, characterized in that the vacuum pressure infiltration process for die castings comprises the following steps: Step S1, infiltration pretreatment: immersing the die casting into a degreasing solution for degreasing treatment, then immersing it into a cleaning solution, washing it with water at a predetermined temperature, and drying it, then immersing the die casting into a polishing solution for selective self-dissolution to reduce the surface roughness of the die casting, and finally high-pressure washing the die casting; Step S2, impregnation treatment: the pre-treated die casting is placed in an impregnation tank and vacuumed for 5 minutes. The impregnant is sucked in by the negative pressure in the impregnation tank. When the impregnant submerges the upper end of the die casting, the pressure is increased and vacuumed again for 3 minutes. Then the pressure is slowly released to normal pressure and the die casting is taken out. Step S3, laser cleaning: using a liquid zoom laser cleaning head device to clean the uneven metal surface, screw holes and surface impregnation liquid on the die casting surface, so that the surface impregnation agent is cleaned; Step S4, post-impregnation treatment: The die casting obtained in step S3 is immersed in water for rotating running water rinsing, and then placed in a curing tank, the die casting is rotated in the curing tank, and then cured in hot water. After curing, it is rinsed with running water and then placed in a drying tank to dry the die casting with high-speed hot air.

[0007] As a preferred embodiment of the present invention, in step S1, the degreasing solution is trichloroethylene.

[0008] As a preferred embodiment of the present invention, in step S1, the cleaning solution comprises, by mass fraction, 7.5% phosphoric acid, 7.5% chromium oxide, 5.0% alcohol and 80% formaldehyde, the formaldehyde concentration is 36%, and the predetermined temperature is 60°C.

[0009] As a preferred embodiment of the present invention, in step S1, the polishing solution comprises, by mass fraction, 75% concentrated phosphoric acid, 8.8% concentrated sulfuric acid, 8.8% concentrated nitric acid, 3.1% urea, 4.4% ammonium sulfate and 0.02% copper sulfate, the polishing temperature is 100°C, and the polishing time is 2 minutes.

[0010] As a preferred embodiment of the present invention, in step S2, the height of the infiltrant is 1 cm higher than the upper end of the die casting.

[0011] As a preferred embodiment of the present invention, in step S3, the liquid zoom laser cleaning head device includes a laser generator, a straightening mirror, a protective mirror, a galvanometer, a beam mirror, a liquid zoom lens and a focusing lens. The light beam is irradiated on the liquid zoom lens, and the focal length of the light beam passing through the liquid zoom lens is continuously changed, and the light beam is automatically zoomed during the cleaning process to clean the uneven metal surface of the die-casting.

[0012] As a preferred embodiment of the present invention, in step S4, the curing temperature is 90° C. and the curing time is 10 minutes.

[0013] In step S4, the die casting is subjected to rotational motion in the curing tank for 15 minutes.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a vacuum pressure infiltration process for die castings. Through infiltration pretreatment, infiltration treatment, laser cleaning and infiltration post-treatment, the process flow of the present invention is simple to operate. After the infiltration treatment, the die castings are subjected to laser cleaning and surface treatment, which solves the problems of internal looseness and micropore defects of the die castings and the difficulty in cleaning of screw holes and process holes blocked by the infiltration agent during the infiltration process, effectively prolongs the service life of the die castings, has good infiltration effect, and effectively improves the infiltration finished product rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the scheme of the present invention, a brief introduction is given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 It is a schematic diagram of the process flow of the vacuum pressure infiltration process of the die casting of the present invention. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Example

[0018] The vacuum pressure infiltration process for die castings includes the following steps: Step S1: Infiltration pretreatment After degreasing, the die castings are ground, polished, cleaned and dried to remove impurities and residues on the surface of the die castings; The specific method is to put the die casting into a degreasing solution for degreasing treatment, and the degreasing solution is trichloroethylene. After degreasing, the following solution is used: according to the mass fraction, the degreasing solution is 7.5% phosphoric acid, 7.5% chromium oxide, 5.0% alcohol, and 80% formaldehyde (concentration 36%), and then washed and dried at 60°C.

[0019] The die casting is placed in an acidic or alkaline electrolytic solution for selective self-dissolution to reduce surface roughness.

[0020] The polishing solution includes the following components by weight: 75% concentrated phosphoric acid, 8.8% concentrated sulfuric acid, 8.8% concentrated nitric acid, 3.1% urea, 4.4% ammonium sulfate and 0.02% copper sulfate. The polishing temperature is 100°C and the polishing time is 2 minutes.

[0021] After polishing, the high-pressure water jet from the high-pressure water gun is used to rinse the polished surface of the die-casting.

[0022] Step S2: Infiltration treatment The pre-treated die casting is placed in an impregnation tank and vacuumed for 5 minutes. The impregnation agent is sucked in by the negative pressure in the tank. When the impregnation liquid submerges the upper end of the die casting and the height of the impregnation agent is 1 cm higher than the die casting, the pressure is increased and vacuumed for 3 minutes again. Then the pressure is slowly released to normal pressure and the die casting is taken out. Step S3: Laser cleaning The removed die castings are cleaned with a liquid zoom laser cleaning head device to clean the uneven metal surface, screw holes and surface impregnation liquid of the die castings, so that the surface impregnation agent is cleaned; the liquid zoom laser cleaning head device includes a laser generator, a straightening mirror, a protective mirror, a galvanometer, a beam mirror, a liquid zoom lens and a focusing lens. The light beam is irradiated on the liquid zoom lens, and the focal length of the light beam through the liquid zoom lens is constantly changed. It can automatically zoom during the cleaning process, effectively ensuring that the laser cleaning can clean the uneven metal surface of the die casting.

[0023] Step S4: Post-infiltration treatment The laser cleaned die castings were immersed in water for rotating water rinsing, then placed in a curing tank, where they were rotated for 15 minutes, and then cured in hot water at a curing temperature of 90°C for 10 minutes.

[0024] After solidification, rinse with running water and then place in a drying tank to dry the die casting with high-speed hot air. Example

[0025] The vacuum pressure infiltration process for die castings includes the following steps: Step S1: Infiltration pretreatment After degreasing, the die castings are ground, polished, cleaned and dried to remove impurities and residues on the surface of the die castings; The specific method of degreasing treatment is to put the die casting into a degreasing solution for degreasing treatment, and the degreasing solution is trichloroethylene.

[0026] After degreasing, the surface was treated with the following solution: the degreasing solution contained 7.5% phosphoric acid, 7.5% chromium oxide, 5.0% alcohol, and 80% formaldehyde (38%) in terms of mass fraction, and then washed with water at 80°C and dried.

[0027] The specific method of polishing treatment is to place the die casting in an acidic or alkaline electrolytic solution for selective self-dissolution to reduce the surface roughness.

[0028] The polishing solution includes the following components by weight: 75% concentrated phosphoric acid, 8.8% concentrated sulfuric acid, 8.8% concentrated nitric acid, 3.1% urea, 4.4% ammonium sulfate, and 0.02% copper sulfate. The polishing temperature is 150° C. and the polishing time is 3 minutes.

[0029] After polishing, the high-pressure water jet from the high-pressure water gun is used to rinse the polished surface of the die-casting.

[0030] Step S2: Infiltration treatment The pre-treated die casting is placed in an impregnation tank and vacuumed for 10 minutes. The impregnation agent is sucked in by the negative pressure in the tank. When the impregnation liquid submerges the upper end of the die casting and the height of the impregnation agent is 3 cm higher than the die casting, the pressure is increased and vacuumed for 6 minutes again. Then the pressure is slowly released to normal pressure and the die casting is taken out. Step S3: Laser cleaning The taken-out die casting is cleaned with a liquid zoom laser cleaning head device to clean the uneven metal surface, screw holes and impregnation liquid on the die casting surface, so that the surface impregnation agent is cleaned; The liquid zoom laser cleaning head device includes a laser generator, a straightening mirror, a protective mirror, a galvanometer, a beam mirror, a liquid zoom lens and a focusing lens. The light beam is irradiated on the liquid zoom lens, and the focal length of the light beam passing through the liquid zoom lens is constantly changed. It can automatically zoom during the cleaning process, effectively ensuring that the laser cleaning can clean the uneven metal surface of the die casting.

[0031] Step S4: Post-infiltration treatment After laser cleaning, the die castings are immersed in water for rotating water rinsing. Then they are placed in a curing tank, rotated for 15 minutes in a curing tank at a curing temperature of 95°C, and then cured in hot water. After curing, they are rinsed with running water and placed in a drying tank for drying with high-speed hot air.

[0032] By adopting the vacuum pressure infiltration process for die castings of the present invention, the problems of looseness and micropore defects inside the die castings and the difficulty in cleaning of screw holes and process holes blocked by the infiltration agent during the infiltration process are solved, thereby improving the service life of the die castings and the infiltration yield rate.

[0033] Obviously, the embodiments described above are only part of the embodiments of the present application, rather than all the embodiments. The drawings provide preferred embodiments of the present application, but do not limit the patent scope of the present application.

Claims

1. A vacuum pressure infiltration process for die castings, characterized in that: The vacuum pressure infiltration process for die castings comprises the following steps: Step S1, infiltration pretreatment: immersing the die casting into a degreasing solution for degreasing treatment, then immersing it into a cleaning solution, washing it with water at a predetermined temperature, and drying it, then immersing the die casting into a polishing solution for selective self-dissolution to reduce the surface roughness of the die casting, and finally high-pressure washing the die casting; Step S2, impregnation treatment: the pre-treated die casting is placed in an impregnation tank and vacuumed for 5 minutes. The impregnant is sucked in by the negative pressure in the impregnation tank. When the impregnant submerges the upper end of the die casting, the pressure is increased and vacuumed again for 3 minutes. Then the pressure is slowly released to normal pressure and the die casting is taken out. Step S3, laser cleaning: using a liquid zoom laser cleaning head device to clean the uneven metal surface, screw holes and surface impregnation liquid on the die casting surface, so that the surface impregnation agent is cleaned; Step S4, post-impregnation treatment: The die casting obtained in step S3 is immersed in water for rotating running water rinsing, and then placed in a curing tank, the die casting is rotated in the curing tank, and then cured in hot water. After curing, it is rinsed with running water and then placed in a drying tank to dry the die casting with high-speed hot air.

2. The vacuum pressure infiltration process for die casting according to claim 1, characterized in that: In step S1, The degreasing solution is trichloroethylene.

3. The vacuum pressure infiltration process for die casting according to claim 1, characterized in that: In step S1, The cleaning solution comprises, by mass fraction, 7.5% phosphoric acid, 7.5% chromium oxide, 5.0% alcohol and 80% formaldehyde, the formaldehyde concentration is 36%, and the predetermined temperature is 60°C.

4. The vacuum pressure infiltration process for die casting according to claim 1, characterized in that: In step S1, The polishing solution comprises, by mass fraction, 75% concentrated phosphoric acid, 8.8% concentrated sulfuric acid, 8.8% concentrated nitric acid, 3.1% urea, 4.4% ammonium sulfate and 0.02% copper sulfate. The polishing temperature is 100° C. and the polishing time is 2 minutes.

5. The vacuum pressure infiltration process for die casting according to claim 1, characterized in that: In step S2, the height of the infiltrant is 1 cm higher than the upper end of the die casting.

6. The vacuum pressure infiltration process for die casting according to claim 1, characterized in that: In step S3, the liquid zoom laser cleaning head device includes a laser generator, a straightening mirror, a protective mirror, a galvanometer, a beam mirror, a liquid zoom lens and a focusing lens. The light beam is irradiated on the liquid zoom lens. The focal length of the light beam passing through the liquid zoom lens changes continuously, and the light beam automatically zooms during the cleaning process to clean the uneven metal surface of the die-casting.

7. The vacuum pressure infiltration process for die casting according to claim 1, characterized in that: In step S4, the curing temperature is 90° C. and the curing time is 10 minutes.

8. The vacuum pressure infiltration process for die casting according to claim 1, characterized in that: In step S4, the die casting is subjected to rotational motion in the curing tank for 15 minutes.

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