Residual stress removal method, workpiece processing method, composite shot peening and preparation method

Abstract

The present invention relates to the field of surface treatment technology, and specifically discloses a residual stress removal method, comprising: performing shot peening on a workpiece from which residual stress is to be removed, wherein the shot peening medium of the shot peening comprises composite shot peening, and the composite shot peening impacts the workpiece to remove residual stress on the surface of the workpiece; wherein the composite shot peening comprises a shot peening substrate and an organic polymer coating formed on the surface of the shot peening substrate. The present invention also discloses a composite shot peening, comprising a shot peening substrate and an organic polymer coating formed on the surface of the shot peening substrate. The present invention also discloses a preparation method of composite shot peening and a workpiece processing method. By applying the residual stress removal method, workpiece processing method, composite shot peening and its preparation method provided by the present invention, residual stress on the surface of the workpiece can be removed without changing the surface morphology of the material, and the processing accuracy is high, and it can be used for local processing of micro-material surfaces or small-sized workpieces.

Description

Technical Field

[0001] The present invention relates to the technical field of surface treatment, and more particularly to a residual stress removal method, a workpiece processing method, a composite shot peening method and a preparation method thereof. Background Art

[0002] Residual stress refers to the self-balanced internal stress that remains in an object after the removal of external forces or uneven temperature fields. For example, after a workpiece is sandblasted, the surface of the workpiece obtains a certain degree of cleanliness and different degrees of roughness, but at the same time, residual stress remains in the workpiece after sandblasting.

[0003] Heat treatment is typically used to remove residual stress from a workpiece. This process involves localized plastic deformation or relaxation within the workpiece, which relaxes the residual stress and eliminates it. However, to prevent structural damage to the workpiece due to high temperatures, the heat treatment temperature must be controlled. However, lower temperatures result in incomplete removal of residual stress, making it ineffective in addressing subsequent workpiece deformation.

[0004] In summary, how to effectively solve the problem that residual stress is difficult to remove effectively, which causes deformation of the workpiece during subsequent processing and affects the yield, is a problem that currently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a residual stress removal method, a workpiece processing method, a composite shot peening method and a preparation method, which can effectively solve the problem that residual stress is difficult to effectively remove, thereby causing workpiece deformation and affecting yield.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A residual stress removal method, comprising:

[0008] Shot peening is performed on the workpiece from which residual stress is to be removed, wherein the shot peening medium of the shot peening comprises composite shot peening, and the composite shot peening strikes the workpiece to remove residual stress on the surface of the workpiece;

[0009] The composite shot peening comprises a shot peening substrate and an organic polymer coating formed on the surface of the shot peening substrate.

[0010] Optionally, in the above residual stress removal method, the particle size of the shot peening substrate ranges from 40 μm to 50 μm, and the thickness of the organic polymer coating ranges from 10 μm to 20 μm.

[0011] Optionally, in the above residual stress removal method, the shot peening substrate is a ceramic substrate, and the organic polymer coating includes polyurethane.

[0012] Optionally, in the above residual stress removal method, the shot peening is performed using an air jet system.

[0013] Optionally, in the above residual stress removal method, the compressed air pressure of the air injection system is controlled to be in the range of 0.7 MPa to 1 MPa.

[0014] The residual stress removal method provided by the present invention is applied, and a composite shot peening with an organic polymer coating on the surface is used for shot peening. The composite shot peening hits the workpiece to remove the residual stress on the workpiece surface, thereby improving the mechanical properties of the workpiece and avoiding the deformation of the workpiece affecting the yield. At the same time, when the composite shot peening bombards the surface of the workpiece, the outer organic polymer coating is broken, and the shot peening matrix is in direct contact with the workpiece again, the impact force is relatively reduced, and will not cause the workpiece morphology to change. In addition, since the organic polymer coating can avoid the agglomeration phenomenon of small-sized shot peening, micron-sized composite shot peening can also be used for shot peening, which is more dispersed after spraying, thereby ensuring small-sized and high-precision impact on the workpiece to effectively remove residual stress. In summary, the residual stress removal method provided by the present invention can effectively handle residual stress to avoid the deformation of the workpiece affecting the yield, while not changing the surface morphology of the material, and has high processing accuracy, and can be used for local processing of micro-material surfaces or small-sized workpieces.

[0015] In order to achieve the above object, the present invention also provides a method for preparing a composite shot peening, comprising:

[0016] Preparation of organic polymer coating raw materials;

[0017] The organic polymer coating material is formed on the surface of the shot blasting substrate to form an organic polymer coating to obtain a composite shot blasting.

[0018] Optionally, in the above-mentioned preparation method of composite shot peening, the organic polymer coating raw material is an organic polymer infiltration liquid, and the organic polymer coating raw material is formed on the surface of the shot peening substrate to form an organic polymer coating, specifically comprising:

[0019] The shot blasting substrate is immersed in the organic polymer infiltration liquid, and an organic polymer coating is formed on the surface of the shot blasting substrate after standing.

[0020] Optionally, in the above-mentioned method for preparing composite shot peening, the solid content of the organic polymer impregnation liquid ranges from 10% to 15%.

[0021] Optionally, in the above-mentioned method for preparing composite shot blasting, the organic polymer impregnation liquid includes an additive and a curing agent, the additive is a mixed solvent of water-soluble polyurethane and water, and the volume ratio of the water-soluble polyurethane to water is 2.5-3.5 to 6.5-7.5, and the curing agent is a mixture of dihydrogen carbide and water, and the volume ratio of the dihydrogen carbide to water is 3.5-4.5 to 5.5-6.5.

[0022] Optionally, in the above-mentioned preparation method of composite shot peening, the particle size of the shot peening substrate ranges from 40 μm to 50 μm, and the thickness of the organic polymer coating ranges from 10 μm to 20 μm.

[0023] In order to achieve the above object, the present invention also provides a composite shot peening method for shot peening to remove residual stress on the surface of a workpiece, comprising a shot peening substrate and an organic polymer coating formed on the surface of the shot peening substrate.

[0024] Optionally, in the above composite shot peening, the particle size of the shot peening matrix ranges from 40 μm to 50 μm, and the thickness of the organic polymer coating ranges from 10 μm to 20 μm.

[0025] Optionally, in the above-mentioned composite shot peening, the organic polymer coating is a polyurethane coating, and the shot peening substrate is a ceramic substrate.

[0026] The composite shot peening and preparation method provided by the present invention are applied, and the obtained composite shot peening is used for shot peening treatment. The composite shot peening hits the surface of the workpiece to remove the residual stress on the surface of the workpiece, thereby improving the mechanical properties and avoiding deformation of the workpiece to affect the yield. At the same time, when the composite shot peening bombards the surface of the workpiece, the outer organic polymer layer is broken, and the shot peening matrix is in direct contact with the workpiece again, the impact force is relatively reduced, and the morphology of the workpiece will not be changed. In addition, since the organic polymer coating can avoid the agglomeration phenomenon of small-sized shot peening, micron-sized composite shot peening can be used for shot peening treatment, which is more dispersed after spraying, thereby ensuring small-sized and high-precision impact on the workpiece to effectively remove residual stress. In summary, the composite shot peening and preparation method provided by the present invention can remove the residual stress on the surface of the workpiece without changing the surface morphology of the material, and has high processing accuracy, and can be used for local processing of micro-material surfaces or small-sized workpieces.

[0027] In order to achieve the above object, the present invention also provides a workpiece processing method, comprising:

[0028] Sandblasting the workpiece surface;

[0029] The surface of the workpiece that has been sandblasted is subjected to shot peening, wherein the shot peening medium of the shot peening comprises composite shot peening, so as to remove residual stress on the surface of the workpiece; wherein the composite shot peening comprises a shot peening substrate and an organic polymer coating formed on the surface of the shot peening substrate;

[0030] The surface of the workpiece that has been shot blasted is anodized.

[0031] Optionally, in the above workpiece processing method, the particle size of the shot peening substrate ranges from 40 μm to 50 μm, and the thickness of the organic polymer coating ranges from 10 μm to 20 μm.

[0032] The workpiece processing method provided by the present invention is applied, and the workpiece is first sandblasted to change the surface morphology of the workpiece. After sandblasting, residual stress exists on the surface of the workpiece, so shot peening is performed, and the surface of the workpiece is impacted by composite shot peening to remove the residual stress on the surface of the workpiece. When the composite shot peening bombards the surface of the workpiece, the outer organic polymer layer is broken, and the shot peening matrix is in direct contact with the workpiece again, and the impact force is relatively reduced, which will not cause the morphology of the workpiece to change. In addition, since the organic polymer coating can avoid the agglomeration phenomenon of small-sized shot peening, micron-sized composite shot peening can be used for shot peening, which is more dispersed after spraying, thereby ensuring small-sized and high-precision impact on the workpiece to effectively remove residual stress. After shot peening, anodizing is performed. Since shot peening removes the residual stress on the surface of the workpiece, the workpiece will not be deformed after anodizing. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only 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.

[0034] Figure 1 A schematic flow chart of a residual stress removal method according to a specific embodiment of the present invention;

[0035] Figure 2 A schematic diagram of the structure of composite shot peening in a specific embodiment of the present invention;

[0036] Figure 3 This is the morphology of composite shot peening;

[0037] Figure 4 A schematic flow chart of a method for preparing composite shot peening according to a specific embodiment of the present invention;

[0038] Figure 5 This is the surface morphology of the workpiece before shot peening in Example 2;

[0039] Figure 6 This is the surface morphology of the workpiece after shot peening in Example 2;

[0040] Figure 7 This is the surface morphology of the workpiece before shot peening in Example 5;

[0041] Figure 8 This is the surface morphology of the workpiece after shot peening in Example 5;

[0042] Figure 9 This is the surface morphology of the workpiece before shot peening in Example 7;

[0043] Figure 10 This is the surface morphology of the workpiece after shot peening in Example 7.

[0044] The following are marked in the accompanying drawings:

[0045] Composite shot peening 1, shot peening substrate 11, organic polymer coating 12. DETAILED DESCRIPTION

[0046] The embodiments of the present invention disclose a residual stress removal method, a workpiece processing method, a composite shot peening method and a preparation method, so as to effectively remove residual stress and avoid deformation of the workpiece without changing the surface morphology of the material.

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 efforts are within the scope of protection of the present invention.

[0048] The residual stress removal method provided by the present invention is applicable to, but not limited to, the removal of residual stress in relatively precise components such as mobile phone frames. That is, the workpieces referred to in the present invention include, but are not limited to, mobile phone accessories and precision components. Taking a mobile phone frame as an example, residual stress exists on the workpiece surface after sandblasting, and the surface requirements of the material are relatively high. Therefore, after conventional heat treatment and then anodizing, a large number of defective products with deformed frames appear. The residual stress removal method provided by the present invention can remove residual stress without changing the surface appearance of the material.

[0049] See also Figure 1 , Figure 1 Schematic diagram of a residual stress removal method according to a specific embodiment of the present invention.

[0050] In a specific embodiment, the residual stress removal method provided by the present invention comprises the following steps:

[0051] S11: Shot peening is performed on the workpiece from which residual stress is to be removed, and the shot peening medium of the shot peening includes composite shot peening, which impacts the workpiece to remove residual stress on the surface of the workpiece; wherein the composite shot peening includes a shot peening substrate and an organic polymer coating formed on the surface of the shot peening substrate.

[0052] Shot peening is a cold working process used to apply compressive residual stress to the surface of a component or to remove residual stress through shot peening. In this application, a high-speed shot stream is sprayed onto the surface of the workpiece to cause plastic deformation of the surface of the workpiece, thereby forming a strengthening layer of a certain thickness. The residual stress formed in the strengthening layer can neutralize the residual stress generated on the surface of the part due to processing, thereby removing the residual stress. In this embodiment, composite shot peening is used for shot peening. The structure of the composite shot peening can be found in Figure 2 and Figure 3 The shot peening matrix 11 can provide the impact strength required to hit the workpiece surface, while the outer organic polymer layer can avoid the agglomeration of small-sized shot peening, so that the composite shot peening 1 can meet the needs of small-sized shot peening processing.

[0053] The residual stress removal method provided by the present invention is applied, and a composite shot peening 1 having an organic polymer coating 12 on the surface is used for shot peening. The composite shot peening 1 impacts the workpiece to remove the residual stress on the surface of the workpiece, thereby improving the mechanical properties of the workpiece and avoiding deformation of the workpiece affecting the yield. At the same time, when the composite shot peening 1 bombards the surface of the workpiece, the outer organic polymer layer is broken, and the shot peening matrix 11 is in direct contact with the workpiece again, and the impact force is relatively reduced, which will not cause the workpiece morphology to change. In addition, since the organic polymer coating 12 can avoid the agglomeration phenomenon of small-sized shot peening, micron-sized composite shot peening 1 can be used for shot peening, which is more dispersed after spraying, thereby ensuring small-sized and high-precision impact on the workpiece to effectively remove residual stress. In summary, the residual stress removal method provided by the present invention can process residual stress without changing the surface morphology of the material, and has high processing accuracy, and can be used for local processing of micro-material surfaces or small-sized workpieces.

[0054] In one embodiment, see Figure 3, the particle size range of the shot peening substrate 11 is 40μm to 50μm, and the thickness range of the organic polymer coating 12 is 10μm to 20μm for composite shot peening. The existing shot peening process is mainly aimed at large parts, large equipment such as construction, transportation, and aviation. For more precise parts such as mobile phone accessories, it is currently not applicable due to the limitation of the size of the shot peening medium. If the size of the shot peening medium is too large, it will affect the surface morphology of the material. Therefore, the shot peening technology for precision parts needs to make the size of the shot peening medium smaller in order to remove residual stress without changing the surface morphology. The size of the shot peening medium is limited because when the shot size is too small, it is easy to cause agglomeration, which increases the particle size, so it cannot meet the demand.

[0055] In this application, a composite shot 1 is used to modify the surface of the shot base 11 using an organic polymer coating 12, thereby inhibiting contact between the composite shot 1 and reducing the interaction between the composite shot 1. Furthermore, the organic polymer coating 12 is coated on the surface of the shot base 11, thereby enlarging the shot size, thereby improving the dispersion of the composite shot 1, allowing the composite shot 1 to separate from each other, effectively improving the phenomenon of small-sized agglomeration, and overcoming the technical bottleneck of fine-grained shot peening without agglomeration. Therefore, the composite shot 1 with a particle size range of 40 μm to 50 μm for the shot base 11 and a thickness range of 10 μm to 20 μm for shot peening can be used to perform small-scale, high-precision impact on the workpiece, effectively removing residual stress. Of course, depending on the workpiece being shot peened, the particle size of the composite shot 1 is not limited to the above numerical range. Composite shots 1 with larger or smaller particle sizes can also be used according to the size of the workpiece and the processing accuracy requirements.

[0056] In one embodiment, the organic polymer coating 12 comprises a polyurethane coating. Polyurethane coatings cure quickly and are simple to prepare, making them easy to form on the shot-peening substrate 11. Furthermore, the polyurethane coating is colorless and odorless, yet relatively weak. When struck against the workpiece surface, it easily breaks, allowing direct contact between the shot-peening substrate 11 and the workpiece to remove residual stress. In other embodiments, the organic polymer coating 12 is not limited to polyurethane coatings; for example, polyvinyl acetate coatings, polyester resin coatings, and the like may be employed, depending on the workpiece.

[0057] In one embodiment, the shot peening substrate 11 is a ceramic substrate. The ceramic substrate has excellent strength, thereby being able to provide the impact strength required to remove residual stress when impacting the workpiece. In other embodiments, a metal substrate or a glass substrate may also be used depending on the workpiece.

[0058] In one embodiment, shot peening is performed using an air jet system in step S11. The air jet system uses high-pressure air through a nozzle to spray the workpiece. The specific jet power is set according to the residual stress removal requirements of the workpiece and is not specifically limited here. Using an air jet system for shot peening can achieve excellent residual stress removal results.

[0059] In one embodiment, an air jet system is used for shot peening, and the compressed air pressure of the air jet system is controlled to be in the range of 0.7 MPa to 1 MPa, so as to obtain an excellent residual stress removal effect without changing the surface morphology.

[0060] In other embodiments, a centrifugal flywheel shot blasting machine may also be used for shot peening. The centrifugal shot blasting machine uses a high-speed flywheel, adjusts the shot peening medium inlet position to release the shot peening medium at a regular time, and uses centrifugal force to push the shot peening medium. The specific flywheel jet speed is set according to the requirement of removing residual stress of the workpiece, and is not specifically limited here.

[0061] The present invention also provides a method for preparing composite shot peening, wherein the composite shot peening prepared by the method is applicable to but not limited to the above-mentioned residual stress removal method. In a specific embodiment, refer to Figure 4 The preparation method of the composite shot peening comprises the following steps:

[0062] S21: preparing organic polymer coating raw materials;

[0063] S22: forming an organic polymer coating raw material on the surface of the shot peening substrate to form an organic polymer coating to obtain a composite shot peening.

[0064] The specific materials for the shot peening substrate and the organic polymer coating can be found in the descriptions of the above embodiments and will not be further described here. The shot peening substrate can be prepared by machining or other methods, and the organic polymer coating raw material can be prepared by mixing or other methods. The prepared organic polymer coating raw material is then molded onto the surface of the shot peening substrate to form the organic polymer coating, thereby ultimately producing a composite shot peening material.

[0065] The preparation method of the composite shot peening provided by the present application is applied, and the obtained composite shot peening is used for shot peening treatment. The composite shot peening impacts the surface of the workpiece to remove the residual stress on the surface of the workpiece, thereby improving the mechanical properties of the workpiece and avoiding deformation of the workpiece affecting the yield. At the same time, when the composite shot peening bombards the surface of the workpiece, the outer organic polymer layer breaks, the shot peening matrix is in direct contact with the workpiece, the impact force is relatively reduced, and the morphology of the workpiece will not be changed. In addition, since the organic polymer coating can avoid the agglomeration phenomenon of small-sized shot peening, micron-sized composite shot peening can be used for shot peening treatment, which is more dispersed after spraying, thereby ensuring small-sized and high-precision impact on the workpiece to effectively remove residual stress. In summary, the preparation method of the composite shot peening provided by the present invention can remove the residual stress on the surface of the workpiece without changing the surface morphology of the material, and has high processing accuracy, and can be used for local processing of micro-material surfaces or small-sized workpieces.

[0066] In one embodiment, the organic polymer coating raw material is an organic polymer infiltration liquid, and in the above step S22, the organic polymer coating raw material is formed on the surface of the shot peening substrate to form an organic polymer coating, specifically comprising: infiltrating the shot peening substrate in the organic polymer infiltration liquid, and forming an organic polymer coating on the surface of the shot peening substrate after standing. In one embodiment, the shot peening substrate can be immersed in the organic polymer infiltration liquid for 12-24 hours by stirring, and then taken out after standing for 12-24 hours. After the shot peening substrate is dispersed and placed, it is dried under vacuum conditions or allowed to stand and dry at room temperature. In this embodiment, the organic polymer coating is formed on the surface of the shot peening substrate by infiltration. The infiltration method can obtain an organic polymer coating with good uniformity, so that the prepared composite shot peening has a good bombardment effect in all directions, so as to effectively remove the residual stress on the workpiece surface.

[0067] In one embodiment, the organic polymer impregnation liquid includes an additive and a curing agent. The additive is a mixed solvent of water-soluble polyurethane and water, and the volume ratio of the water-soluble polyurethane to water is 2.5-3.5:6.5-7.5. The curing agent is a mixture of dihydrogen carbide and water, and the volume ratio of the dihydrogen carbide to water is 3.5-4.5:5.5-6.5. The polyurethane coating is formed on the surface of the shot peening substrate by the impregnation liquid.

[0068] Furthermore, the organic polymer impregnation liquid can be prepared according to the following steps:

[0069] S31: mixing an additive with a curing agent, wherein the additive is a mixed solvent of water-soluble polyurethane and water, and the volume ratio of the water-soluble polyurethane to water is 2.5-3.5:6.5-7.5; and the curing agent is a mixture of dihydrogen amine carbide and water, and the volume ratio of the dihydrogen amine carbide to water is 3.5-4.5:5.5-6.5; stirring, specifically, the stirring speed range is 250 rpm to 300 rpm, and the stirring time is 5-10 minutes;

[0070] S32: adding isopropyl alcohol-based infiltration liquid; stirring, specifically stirring speed range is 250 rpm~300 rpm, stirring time is 5-10 minutes;

[0071] S33: adding diluent or deionized water; stirring, specifically stirring speed range is 250 rpm to 300 rpm, stirring time is 1-5 minutes;

[0072] S34: Filter to obtain the filtrate, which is then sealed and allowed to stand for defoaming to obtain the organic polymer impregnation solution. The standing time is 5-10 minutes.

[0073] In the above embodiment, the organic polymer coating raw material is an organic polymer infiltration liquid. In other embodiments, the organic polymer coating raw material can also be an organic polymer coating powder, etc., such as preparing the organic polymer coating powder by ball milling, and then forming it on the shot peening substrate by coating or spraying to form an organic polymer coating.

[0074] In one embodiment, the solid content of the organic polymer impregnation liquid ranges from 10% to 15%. Different solid contents result in different surface morphologies and residual stress removal effects on the workpiece after shot peening using the resulting composite shot. Using an impregnation liquid with a solid content range of 10% to 15% can achieve excellent residual stress removal without affecting the workpiece's surface morphology. Of course, depending on the workpiece being shot peened, the solid content of the organic polymer impregnation liquid is not limited to the aforementioned numerical range and can be increased or decreased based on the workpiece's shot peening requirements.

[0075] In one embodiment, the particle size of the shot peening substrate ranges from 40 μm to 50 μm, and the thickness of the organic polymer coating ranges from 10 μm to 20 μm. Using composite shot peening with the aforementioned particle size ranges for shot peening can achieve small-scale, high-precision impacts on workpieces, is less prone to agglomeration, and effectively removes residual stress.

[0076] The embodiment of the present invention also provides a composite shot peening method for removing residual stress on the surface of a workpiece by shot peening. Figure 2 and Figure 3In one embodiment, the composite shot 1 includes a shot base 11 and an organic polymer coating 12 formed on the surface of the shot base 11. Specifically, the composite shot 1 can be prepared by any one of the preparation methods in the above embodiments.

[0077] In one embodiment, the particle size of the shot peening substrate 11 is in the range of 40 μm to 50 μm, and the thickness of the organic polymer coating 12 is in the range of 10 μm to 20 μm.

[0078] In one embodiment, the organic polymer coating 12 is a polyurethane coating.

[0079] In one embodiment, the shot peening substrate 11 is a ceramic substrate.

[0080] The composite shot peening 1 provided by the present invention is used for shot peening treatment. The composite shot peening 1 impacts the surface of the workpiece to remove the residual stress on the surface of the workpiece, thereby improving the mechanical properties of the workpiece and avoiding deformation of the workpiece affecting the yield. At the same time, when the composite shot peening 1 bombards the surface of the workpiece, the outer organic polymer layer is broken, and the shot peening matrix 11 is in direct contact with the workpiece. The impact force is relatively reduced and will not cause the morphology of the workpiece to change. In addition, since the organic polymer coating 12 can avoid the agglomeration phenomenon of small-sized shot peening, micron-sized composite shot peening 1 can be used for shot peening treatment, which is more dispersed after spraying, thereby ensuring small-sized and high-precision impact on the workpiece to effectively remove residual stress. In summary, the composite shot peening 1 provided by the present invention can remove residual stress on the surface of the workpiece without changing the surface morphology of the material, and has high processing accuracy, and can be used for local processing of micro-material surfaces or small-sized workpieces.

[0081] In order to more clearly illustrate the significant advantages of the residual stress removal method, composite shot peening and preparation method thereof provided by the present invention in residual stress removal, a plurality of embodiments are used for comparative description below.

[0082] Example 1

[0083] The workpiece is shot peened by composite shot peening, which includes a ceramic matrix and a polyurethane coating coated on the surface of the ceramic matrix by infiltration. The particle size of the composite shot peening matrix is 40 μm, and the solid content of the infiltration liquid is 5%.

[0084] Example 2

[0085] The solid content of the infiltration liquid is 10%, and the other parameters are the same as those in Example 1.

[0086] Example 3

[0087] The solid content of the infiltration liquid is 20%, and the other parameters are the same as those in Example 1.

[0088] The residual stress test results of the workpiece before and after shot peening are shown in Table 1.

[0089] Table 1 Residual stress test results of workpiece before and after shot peening

[0090]

[0091] It can be seen that in Example 2, a polyurethane coating is formed on the surface of the ceramic substrate by infiltration using an infiltration liquid with a solid content of 10%. The composite shot peening obtained has the best residual stress elimination effect after shot peening. The surface morphology photos of the workpiece before and after shot peening corresponding to Example 2 are shown in FIG. Figure 5 and Figure 6 As shown, the surface morphology of the workpiece remains basically unchanged.

[0092] Example 4

[0093] The workpiece is shot peened by composite shot peening, which includes a ceramic matrix and a polyurethane coating coated on the surface of the ceramic matrix by infiltration. The particle size of the composite shot peening matrix is 20 μm, and the solid content of the infiltration liquid is 10%.

[0094] Example 5

[0095] The particle size of the shot peening matrix of the composite shot peening is 40 μm, and the other parameters are the same as those in Example 4.

[0096] Example 6

[0097] The particle size of the shot peening matrix of the composite shot peening is 80 μm, and the other parameters are the same as those in Example 4.

[0098] The residual stress test results of the workpiece before and after shot peening are shown in Table 2.

[0099] Table 2 Residual stress test results of workpiece before and after shot peening

[0100]

[0101] It can be seen that Example 5, that is, the composite shot peening with a shot peening matrix particle size of 40 μm, has a good residual stress elimination effect. The surface morphology photos of the workpiece before and after shot peening corresponding to Example 5 are shown in FIG. Figure 7 and Figure 8 As shown in the figure, it can be seen that it does not cause changes in the surface morphology. The composite shot peening with a shot peening matrix particle size of 80μm has a certain effect on the surface morphology of the workpiece, while the composite shot peening with a shot peening matrix particle size of 20μm has a lower residual stress removal effect than the composite shot peening with a particle size of 40μm.

[0102] Example 7

[0103] The workpiece is shot peened using composite shot peening, which includes a ceramic matrix and a polyurethane coating coated on the surface of the ceramic matrix by infiltration. The particle size of the shot peening matrix of the composite shot peening is 40 μm, the solid content of the infiltration liquid is 10%, and the shot peening is performed using an air jet system.

[0104] Example 8

[0105] The shot blasting was performed using a centrifugal shot blasting machine, and the other parameters were the same as those in Example 7.

[0106] The residual stress test results of the workpiece before and after shot peening are shown in Table 3.

[0107] Table 3 Residual stress test results of workpiece before and after shot peening

[0108]

[0109] It can be seen that the residual stress elimination effect after shot peening by the air jet system in Example 7 is the best. The surface morphology photos of the workpiece before and after shot peening corresponding to Example 7 are shown in FIG. Figure 9 and Figure 10 As shown, the surface morphology remains basically unchanged.

[0110] The present application also provides a workpiece processing method, comprising the following steps:

[0111] S41: sandblasting the workpiece surface;

[0112] S42: performing shot peening on the surface of the workpiece that has been sandblasted, wherein the shot peening medium of the shot peening includes composite shot peening, so as to remove residual stress on the surface of the workpiece; wherein the composite shot peening includes a shot peening substrate and an organic polymer coating formed on the surface of the shot peening substrate;

[0113] S43: Anodizing the shot-peened workpiece surface.

[0114] The workpiece processing method provided by the present application is applied, and the workpiece is first sandblasted to change the surface morphology of the workpiece. After sandblasting, residual stress exists on the surface of the workpiece, so shot peening is performed, and the surface of the workpiece is impacted by composite shot peening to remove the residual stress on the surface of the workpiece, and when the composite shot peening bombards the surface of the workpiece, the outer organic polymer layer is broken, and the shot peening matrix is in direct contact with the workpiece again, and the impact force is relatively reduced, which will not cause the morphology of the workpiece to change. In addition, since the organic polymer coating can avoid the agglomeration phenomenon of small-sized shot peening, micron-sized composite shot peening can be used for shot peening, which is more dispersed after spraying, thereby ensuring small-sized and high-precision impact on the workpiece to effectively remove residual stress. After shot peening, anodizing is performed. Since shot peening removes the residual stress on the surface of the workpiece, the workpiece will not be deformed after anodizing. Anodizing is a prior art, and the process parameters are different according to different products. It is well known to those skilled in the art and will not be described in detail.

[0115] In one embodiment, the particle size of the shot peening substrate ranges from 40 μm to 50 μm, and the thickness of the organic polymer coating ranges from 10 μm to 20 μm.

[0116] In one embodiment, the organic polymer coating is a polyurethane coating.

[0117] In one embodiment, the shot peening substrate is a ceramic substrate.

[0118] In one embodiment, in step S42 , an air jet system is used for shot peening.

[0119] In one embodiment, an air jet system is used for shot peening, and the compressed air pressure of the air jet system is controlled to be in the range of 0.7 MPa to 1 MPa, so as to obtain an excellent residual stress removal effect without changing the surface morphology.

[0120] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0121] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for removing residual stress, characterized in that: include: Shot peening is performed on the workpiece from which residual stress is to be removed, wherein the shot peening medium of the shot peening comprises composite shot, and the composite shot peening strikes the workpiece to remove residual stress on the surface of the workpiece; The composite shot peening comprises a shot peening substrate and an organic polymer coating formed on the surface of the shot peening substrate; the particle size of the shot peening substrate ranges from 40 μm to 50 μm, and the thickness of the organic polymer coating ranges from 10 μm to 20 μm.

2. The residual stress removal method according to claim 1, characterized in that: The shot blasting substrate is a ceramic substrate, and the organic polymer coating comprises polyurethane.

3. The residual stress removal method according to claim 1, characterized in that: In the shot blasting process, an air jet system is used for the shot blasting process.

4. The residual stress removal method according to claim 3, characterized in that: The compressed air pressure range of the air injection system is controlled to be 0.7 MPa to 1 MPa.

5. A method for preparing composite shot peening, characterized in that: include: Preparation of organic polymer coating raw materials; The organic polymer coating raw material is formed on the surface of a shot peening substrate to form an organic polymer coating to obtain a composite shot peening; the particle size of the shot peening substrate ranges from 40 μm to 50 μm, and the thickness of the organic polymer coating ranges from 10 μm to 20 μm.

6. The method for preparing composite shot according to claim 5, characterized in that: The organic polymer coating raw material is an organic polymer infiltration liquid, and the organic polymer coating raw material is formed on the surface of the shot blasting substrate to form the organic polymer coating, specifically comprising: The shot blasting substrate is immersed in the organic polymer infiltration liquid, and an organic polymer coating is formed on the surface of the shot blasting substrate after standing.

7. The method for preparing composite shot according to claim 6, characterized in that: The solid content of the organic polymer impregnation solution is in the range of 10% to 15%.

8. The method for preparing composite shot according to any one of claims 5 to 7, characterized in that: The organic polymer impregnation liquid includes an additive and a curing agent. The additive is a mixed solvent of water-soluble polyurethane and water, and the volume ratio of the water-soluble polyurethane to water is 2.5-3.5 to 6.5-7.

5. The curing agent is a mixture of dihydrogen carbide and water, and the volume ratio of the dihydrogen carbide to water is 3.5-4.5 to 5.5-6.

5.

9. A composite shot peening method for removing residual stress on the surface of a workpiece by shot peening, characterized in that: The invention comprises a shot peening substrate and an organic polymer coating formed on the surface of the shot peening substrate; the particle size of the shot peening substrate ranges from 40 μm to 50 μm, and the thickness of the organic polymer coating ranges from 10 μm to 20 μm.

10. The composite shot peening according to claim 9, characterized in that: The organic polymer coating is a polyurethane coating, and the shot blasting substrate is a ceramic substrate.

11. A workpiece processing method, characterized in that: include: Sandblasting the workpiece surface; The surface of the workpiece that has been sandblasted is subjected to shot peening, wherein the shot peening medium of the shot peening comprises composite shot peening, so as to remove residual stress on the surface of the workpiece; wherein the composite shot peening comprises a shot peening substrate and an organic polymer coating formed on the surface of the shot peening substrate, the particle size of the shot peening substrate ranges from 40 μm to 50 μm, and the thickness of the organic polymer coating ranges from 10 μm to 20 μm; The surface of the workpiece that has been shot blasted is anodized.

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