CN111893285A - Composite strengthening method for prolonging fatigue life and resisting permanent deformation of single leaf spring - Google Patents
Composite strengthening method for prolonging fatigue life and resisting permanent deformation of single leaf spring Download PDFInfo
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- CN111893285A CN111893285A CN202010678417.9A CN202010678417A CN111893285A CN 111893285 A CN111893285 A CN 111893285A CN 202010678417 A CN202010678417 A CN 202010678417A CN 111893285 A CN111893285 A CN 111893285A
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/02—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for springs
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D7/00—Modifying the physical properties of iron or steel by deformation
- C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
- C21D7/04—Modifying the physical properties of iron or steel by deformation by cold working of the surface
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
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Abstract
The invention discloses a composite strengthening method for prolonging the fatigue life and resisting permanent deformation of a single leaf spring, which comprises the following steps: the hardness of the single leaf spring after quenching and tempering heat treatment is 46 HRC-51 HRC, the single leaf spring is kept at the bending stress of 1000 MPa-1250 MPa by using a tool fixture, the first stress shot blasting is carried out by using steel wire shot cutting with the diameter of 0.8 mm-1.2 mm and shot blasting strength of 0.30C-0.35C, then the second stress shot blasting is carried out by using steel wire shot cutting with the diameter of 0.4 mm-0.6 mm and shot blasting strength of 0.20C-0.25C, the bending stress applied by the tool fixture is unloaded after the two stress shot blasting processes are finished, and finally the single leaf spring is heated to 180-220 ℃ to carry out three-point bending loading and unloading for 3 times of circulation. The invention can obviously improve the surface residual compressive stress of the single leaf spring, optimize the distribution of the surface residual compressive stress field and obtain smaller surface roughness, thereby improving the fatigue life and the bearing capacity of the single leaf spring and simultaneously reducing the permanent deformation of the single leaf spring in the using process.
Description
Technical Field
The invention belongs to the technical field of manufacturing of single leaf springs of automobile suspensions, and particularly relates to a composite strengthening method for prolonging the fatigue life of the single leaf springs and resisting permanent deformation.
Background
Leaf spring is the key elastic component in the automotive suspension system, through relaxing the impact of transmitting to the frame by the wheel, influences the ride comfort, the security and the travelling comfort of car, and leaf spring divide into many leaf springs, few leaf spring and single leaf spring etc. according to the structure difference. Along with the development trend of light weight, high reliability and high comfort of automobiles, single leaf springs are widely adopted in automobile suspension systems in foreign countries such as scandinia, gallop, man and the like, the single leaf springs are simple in structure and excellent in vibration reduction effect, friction abnormal sound generated by end contact is eliminated, the weight is reduced by 20% compared with that of the existing 2-3 leaf springs, and the weight of the automobile suspension system is remarkably reduced. The foreign single leaf spring adopts spring steel with high hardenability, high purity and high fatigue strength, the manufacturing process technology of variable cross-section rolling, heat treatment, shot peening, forced pressure treatment and the like is relatively mature, and the single leaf spring has very high reliability and small permanent deformation.
The domestic automobile industry is still in the research stage in single leaf spring material, manufacturing process and application, and the production of single leaf spring follows the manufacturing process technical route of few leaf springs, and each process comprises: blanking flat steel → processing of a central hole → rolling of a variable cross section → end curling → heat treatment → shot peening → forced pressing treatment → surface painting, wherein the shot peening and the forced pressing treatment are key strengthening processes for improving the fatigue life, the bearing capacity and the permanent deformation resistance of the single leaf spring. The prior single-leaf spring shot blasting reinforcement adopts the traditional stress shot blasting, the pre-applied bending stress during the shot blasting is generally 600MPa to 800MPa, meanwhile, the pressure treatment is common normal temperature pressure, and the bending stress applied by the pressure is only 300MPa to 500 MPa. The domestic single leaf spring is subjected to a strengthening process of stress shot blasting and high-pressure treatment, the surface residual compressive stress is only 350-500 MPa, the depth of a surface layer residual compressive stress field is about 0.8mm, the surface residual compressive stress of the domestic single leaf spring reaches 700-900 MPa, the depth of the surface layer residual compressive stress field reaches 2mm, and the difference of surface strengthening effects is large, so that the domestic single leaf spring is low in fatigue life and bearing capacity, easy to generate permanent deformation and the like, and the popularization and application of the single leaf spring in an automobile suspension system are hindered.
Based on the consideration of safety and comfort of an automobile suspension system, a single leaf spring needs to have high reliability and permanent deformation resistance in the use process, and the technical problems of low fatigue life, permanent deformation in the use process and the like of the single leaf spring cannot be solved by adopting the traditional strengthening method at present, so that technical innovation in the aspects of shot peening strengthening, forced pressure treatment and the like of the single leaf spring is urgently needed to improve the fatigue life and the permanent deformation resistance of the single leaf spring.
Disclosure of Invention
Aiming at the technical problems, the invention aims to provide a composite strengthening method for prolonging the fatigue life and resisting the permanent deformation of a single leaf spring by improving the traditional strengthening method of the single leaf spring, so that the single leaf spring obtains high surface residual compressive stress, good surface residual compressive stress field distribution and smaller surface roughness, thereby prolonging the fatigue life and the bearing capacity of the single leaf spring and simultaneously reducing the permanent deformation of the single leaf spring in the using process.
The technical scheme adopted by the invention is as follows:
a composite strengthening method for improving the fatigue life and permanent deformation resistance of a single leaf spring comprises the following steps:
step one, quenching and tempering the single spring, wherein the hardness of the single spring after heat treatment is 46 HRC-51 HRC;
secondly, applying bending load to the single leaf spring by using a tool clamp to keep the single leaf spring at high bending stress;
thirdly, carrying out first stress shot blasting on the coarse shot by the single leaf spring along with the tool fixture;
fourthly, carrying out secondary stress shot blasting on the fine shot by the single leaf spring along with the tool fixture;
fifthly, unloading the bending stress applied by the fixture by the single spring;
and step six, heating the single leaf spring to a certain temperature, and then carrying out three-point bending loading and unloading for 3 times of circulation.
Optionally, in the second step, the bending stress maintained by the tool clamp is 1000MPa to 1250 MPa.
Preferably, the bending stress is 1100MPa to 1200 MPa.
Optionally, in the third step, the coarse shot is a steel wire cut shot with a diameter of 0.8mm to 1.2mm, and the steel wire cut shot is subjected to finishing and rounding treatment, wherein the shot blasting strength is 0.30C to 0.35C, and the shot blasting time is 2min to 5 min.
Preferably, the coarse shot is a steel wire cut shot with the diameter of 1.0mm, the steel wire cut shot is subjected to finishing and rounding treatment, the shot blasting intensity is 0.32-0.33C, and the shot blasting time is 3-4 min.
Optionally, in the fourth step, the fine shot is a steel wire cut shot with a diameter of 0.4mm to 0.6mm, and the steel wire cut shot is subjected to finishing and rounding treatment, wherein the shot blasting strength is 0.20C to 0.25C, and the shot blasting time is 3min to 6 min.
Preferably, the fine shot is a steel wire cut shot with the diameter of 0.5mm, and the steel wire cut shot is subjected to finishing and rounding treatment, the shot blasting intensity is 0.22-0.24C, and the shot blasting time is 4-5 min.
Optionally, in the sixth step, the heating temperature range is 180 ℃ to 220 ℃, and the bending stress of the three-point bending load is 1100MPa to 1300 MPa.
Preferably, the heating temperature range is 210 ℃, and the bending stress of the three-point bending loading is 1200 MPa-1250 MPa.
Optionally, the tool clamp includes a clamp base, a clamping arm, and a force application gasket; the force application gasket is placed on the clamp base and used for supporting the bottom of the bending surface of the single leaf spring to be kept; the two clamping arms can move horizontally relative to the clamp base, and the two clamping arms move horizontally inwards from two ends of the single leaf spring until clamping the single leaf spring which is bent and deformed; the clamping arm and the force application gasket act together to keep the single leaf spring bent and deformed.
Compared with the prior art, the invention at least has the following advantages:
(1) the single leaf spring is loaded and kept at high bending stress by using a tool fixture, high surface residual compressive stress and deep surface residual compressive stress field distribution are obtained through coarse shot and a first stress shot with high shot blasting strength, then the surface residual compressive stress is further improved through fine shot and a second stress shot with high shot blasting strength, smaller surface roughness is obtained, the surface strengthening effect and the surface quality are obviously improved, and therefore the fatigue life of the single leaf spring is prolonged. In addition, the two stress shot blasting processes share one set of tool clamp, the loaded and maintained bending stress is the same, unloading and reloading are not needed in the middle, and the production efficiency is improved.
(2) The single leaf spring is heated at the temperature of 180-220 ℃, and is subjected to three-point bending loading and unloading thermal stress treatment for 3 times of cycles, so that the elastic limit and yield strength of the single leaf spring material are improved, and favorable residual compressive stress distribution opposite to the working stress direction is generated on the surface layer of the single leaf spring material, so that the fatigue life and the bearing capacity of the single leaf spring are improved, the permanent deformation generated in the use process is reduced, and the geometric dimension of the single leaf spring is stabilized.
Drawings
FIG. 1 is a schematic view of a tooling fixture employed in the present invention;
FIG. 2 is a graph showing the surface residual compressive stress of a single leaf spring using a conventional strengthening method and a composite strengthening method of the present invention;
FIG. 3 is a surface residual compressive stress field of a single leaf spring using a conventional strengthening method and a composite strengthening method of the present invention;
FIG. 4 illustrates the surface roughness of a single leaf spring using conventional strengthening methods;
FIG. 5 is a surface roughness of a single leaf spring using the composite strengthening method of the present invention;
FIG. 6 is a flow chart of a composite strengthening method for improving the fatigue life and permanent deformation resistance of a single leaf spring according to the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.
As shown in fig. 6, a composite strengthening method for improving the fatigue life and permanent deformation resistance of a single leaf spring comprises the following steps:
step one, quenching and tempering the single spring, wherein the hardness of the single spring after heat treatment is 46 HRC-51 HRC;
step two, applying bending load to the single leaf spring by using a tool clamp to keep the bending stress of the single leaf spring between 1000MPa and 1250 MPa;
thirdly, carrying out first stress shot blasting on the coarse shot by the single leaf spring along with the tool fixture, wherein the coarse shot is a steel wire cut shot with the diameter of 0.8-1.2 mm, the steel wire cut shot is subjected to finishing and rounding treatment, the shot blasting strength is 0.30-0.35C, and the shot blasting time is 2-5 min;
fourthly, carrying out secondary stress shot blasting on fine pills by the single leaf spring along with the tool fixture, wherein the fine pills are steel wire cut pills with the diameter of 0.4-0.6 mm, the steel wire cut pills are subjected to finishing and rounding treatment, the shot blasting strength is 0.20-0.25C, and the shot blasting time is 3-6 min;
fifthly, unloading the bending stress applied by the fixture by the single spring;
and step six, heating the single leaf spring to 180-220 ℃, and then performing three-point bending loading 1100-1300 MPa bending stress and unloading for 3 times of circulation.
As shown in fig. 1, the work fixture includes a fixture base, a clamping arm, and a force application pad; the force application gasket is placed on the clamp base and used for supporting the bottom of the bending surface of the single leaf spring to be kept; the two clamping arms can move horizontally relative to the clamp base, and the two clamping arms move horizontally inwards from two ends of the single leaf spring until clamping the single leaf spring which is bent and deformed; the clamping arm and the force application gasket act together to keep the single leaf spring bent and deformed.
[ examples ] A method for producing a compound
The technical solution, advantages and the like of the composite reinforcement method of the present invention will be described below by taking a single leaf spring made of 52CrMoV4 steel as an example.
The chemical composition of the single leaf spring material in this example is shown in table 1 below:
TABLE 1 chemical composition (mass fraction,%)
| Chemical elements | C | P | S | Mn | Si | Cr | Mo | V | O |
| Test results | 0.53 | 0.014 | 0.010 | 1.05 | 0.27 | 1.10 | 0.20 | 0.12 | 0.0010 |
[ example 1 ]
In this embodiment, the single leaf spring is processed by the conventional strengthening method and the composite strengthening method of the present invention, and then the surface residual compressive stress field and the surface roughness are tested to determine the surface residual compressive stress, the maximum residual compressive stress depth, the residual compressive stress field depth, the surface roughness Ra and Rz, and other parameters of the single leaf spring processed by different strengthening methods, and the specific test results are shown in table 2. A bench fatigue test of a single leaf spring was conducted to verify the fatigue life and permanent set of the single leaf spring after treatment with different strengthening methods, and the specific test results are shown in table 3.
The traditional strengthening method comprises the following steps: quenching + tempering → stress shot peening under the bending stress of 800MPa is maintained → 1 time of three-point bending loading and unloading of 500 MPa.
The composite strengthening method comprises the following steps: quenching + tempering → applying and maintaining 1000MPa bending stress by using a tooling fixture → first pass stress shot blasting: the diameter of the steel wire shot is 0.8mm, the shot blasting intensity is 0.30C, and the shot blasting time is 2min → the second stress shot blasting: the steel wire shot cutting diameter is 0.4mm, the shot blasting strength is 0.20C, the shot blasting time is 3min → the bending stress applied by an unloading tool clamp → the three-point bending stress of 1100MPa is loaded and unloaded after heating to 220 ℃ for 3 cycles.
TABLE 2 test results of residual compressive stress field and surface roughness of surface layer
As can be seen from Table 2, compared with the conventional strengthening method, the surface residual compressive stress of the single leaf spring treated by the method is improved by 72%, the maximum residual compressive stress is improved by 19%, the maximum residual compressive stress depth is improved by 72%, the residual compressive stress field depth is improved by 76%, the surface roughness Ra is reduced by 63%, and the surface roughness Rz is reduced by 49%. Therefore, the single-piece spring processed by the method has higher surface residual compressive stress and deeper surface residual compressive stress field, and smaller surface roughness.
TABLE 3 bench fatigue test results
As can be seen from Table 3, compared with the conventional strengthening method, the fatigue life of the single-piece spring treated by the method is improved by more than 4 times under different bench test stress conditions, and the permanent deformation before and after the bench test is reduced by more than 54%. Therefore, the single-piece spring processed by the method has higher fatigue life and bearing capacity and smaller permanent deformation.
[ example 2 ]
In this embodiment, the single leaf spring is processed by the conventional strengthening method and the composite strengthening method of the present invention, and then the surface residual compressive stress field and the surface roughness are tested to determine the surface residual compressive stress, the maximum residual compressive stress depth, the residual compressive stress field depth, the surface roughness Ra and Rz, and other parameters of the single leaf spring processed by different strengthening methods, and the specific test results are shown in table 4 and fig. 2 to 5. A bench fatigue test of a single leaf spring was conducted to verify the fatigue life and permanent set of the single leaf spring after treatment with different strengthening methods, and the specific test results are shown in table 5.
The traditional strengthening method comprises the following steps: the procedure is as in example 1.
The composite strengthening method comprises the following steps: quenching + tempering → applying and maintaining 1100MPa of bending stress by using a tool clamp → first pass stress shot blasting: the diameter of the steel wire shot is 1.0mm, the shot blasting intensity is 0.32C, and the shot blasting time is 3min → the second stress shot blasting: the steel wire shot cutting diameter is 0.5mm, the shot blasting strength is 0.22C, the shot blasting time is 4min → the bending stress applied by an unloading tool clamp → the three-point bending stress of 1200MPa is loaded and unloaded after heating to 210 ℃ for 3 cycles.
TABLE 4 test results of residual compressive stress field and surface roughness of surface layer
As can be seen from table 4, compared with the conventional strengthening method, the surface residual compressive stress of the single leaf spring treated by the method of the present invention is increased by 91%, the maximum residual compressive stress is increased by 27%, the maximum residual compressive stress depth is increased by 88%, the residual compressive stress field depth is increased by 87%, the surface roughness Ra is reduced by 61%, and the surface roughness Rz is reduced by 47%. Therefore, the single-piece spring processed by the method has higher surface residual compressive stress and deeper surface residual compressive stress field, and smaller surface roughness.
TABLE 5 bench fatigue test results
As can be seen from Table 5, compared with the conventional strengthening method, the fatigue life of the single-piece spring treated by the method is improved by more than 4 times under different bench test stress conditions, and the permanent deformation before and after the bench test is reduced by more than 63%. Therefore, the single-piece spring processed by the method has higher fatigue life and bearing capacity and smaller permanent deformation.
[ example 3 ]
In this embodiment, the single leaf spring is processed by the conventional strengthening method and the composite strengthening method of the present invention, and then the surface residual compressive stress field and the surface roughness are tested to determine the surface residual compressive stress, the maximum residual compressive stress depth, the residual compressive stress field depth, the surface roughness Ra and Rz, and other parameters of the single leaf spring processed by different strengthening methods, and the specific test results are shown in table 6. A bench fatigue test of a single leaf spring was conducted to verify the fatigue life and permanent set of the single leaf spring after treatment with different strengthening methods, and the specific test results are shown in table 7.
The traditional strengthening method comprises the following steps: the procedure is as in example 1.
The composite strengthening method comprises the following steps: quenching + tempering → applying and maintaining 1200MPa bending stress by using a tooling fixture → first pass stress shot blasting: the diameter of the steel wire shot is 1.0mm, the shot blasting intensity is 0.33C, and the shot blasting time is 4min → the second stress shot blasting: the steel wire shot cutting diameter is 0.5mm, the shot blasting strength is 0.24C, the shot blasting time is 5min → the bending stress applied by an unloading tool clamp → the three-point bending stress of 1250MPa is loaded and unloaded after heating to 200 ℃ for 3 cycles.
TABLE 6 test results of residual compressive stress field and surface roughness of surface layer
As can be seen from table 6, compared with the conventional strengthening method, the surface residual compressive stress of the single leaf spring treated by the method of the present invention is increased by 99%, the maximum residual compressive stress is increased by 27%, the maximum residual compressive stress depth is increased by 100%, the residual compressive stress field depth is increased by 102%, the surface roughness Ra is reduced by 59%, and the surface roughness Rz is reduced by 46%. Therefore, the single-piece spring processed by the method has higher surface residual compressive stress and deeper surface residual compressive stress field, and smaller surface roughness.
TABLE 7 bench fatigue test results
As can be seen from Table 7, compared with the conventional strengthening method, the fatigue life of the single-piece spring treated by the method is improved by more than 4 times under different bench test stress conditions, and the permanent deformation before and after the bench test is reduced by more than 57%. Therefore, the single-piece spring processed by the method has higher fatigue life and bearing capacity and smaller permanent deformation.
[ example 4 ]
In this embodiment, the single leaf spring is processed by the conventional strengthening method and the composite strengthening method of the present invention, and then the surface residual compressive stress field and the surface roughness are tested to determine the surface residual compressive stress, the maximum residual compressive stress depth, the residual compressive stress field depth, the surface roughness Ra and Rz, and other parameters of the single leaf spring processed by different strengthening methods, and the specific test results are shown in table 8. A bench fatigue test of a single leaf spring was conducted to verify the fatigue life and permanent set of the single leaf spring after treatment with different strengthening methods, and the specific test results are shown in table 9.
The traditional strengthening method comprises the following steps: the procedure is as in example 1.
The composite strengthening method comprises the following steps: quenching + tempering → applying and maintaining 1250MPa bending stress by using a tooling fixture → first pass stress shot blasting: the diameter of the steel wire shot is 1.2mm, the shot blasting intensity is 0.35C, and the shot blasting time is 5min → the second stress shot blasting: the steel wire shot cutting diameter is 0.6mm, the shot blasting strength is 0.25C, the shot blasting time is 6min → the bending stress applied by an unloading tool clamp → the three-point bending stress of 1300MPa is loaded and unloaded after heating to 180 ℃ for 3 cycles.
TABLE 8 test results of residual compressive stress field and surface roughness of surface layer
As can be seen from table 8, compared with the conventional strengthening method, the surface residual compressive stress of the single leaf spring treated by the method of the present invention is increased by 103%, the maximum residual compressive stress is increased by 31%, the maximum residual compressive stress depth is increased by 116%, the residual compressive stress field depth is increased by 117%, the surface roughness Ra is reduced by 57%, and the surface roughness Rz is reduced by 40%. Therefore, the single-piece spring processed by the method has higher surface residual compressive stress and deeper surface residual compressive stress field, and smaller surface roughness.
TABLE 9 bench fatigue test results
As can be seen from Table 9, compared with the conventional strengthening method, the fatigue life of the single-piece spring treated by the method is improved by more than 4 times under different bench test stress conditions, and the permanent deformation before and after the bench test is reduced by more than 51%. Therefore, the single-piece spring processed by the method has higher fatigue life and bearing capacity and smaller permanent deformation.
The above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (10)
1. A composite strengthening method for improving the fatigue life and resisting permanent deformation of a single leaf spring is characterized by comprising the following steps:
step one, quenching and tempering the single spring, wherein the hardness of the single spring after heat treatment is 46 HRC-51 HRC;
secondly, applying bending load to the single leaf spring by using a tool clamp to keep the single leaf spring at high bending stress;
thirdly, carrying out first stress shot blasting on the coarse shot by the single leaf spring along with the tool fixture;
fourthly, carrying out secondary stress shot blasting on the fine shot by the single leaf spring along with the tool fixture;
fifthly, unloading the bending stress applied by the fixture by the single spring;
and step six, heating the single leaf spring to a certain temperature, and then carrying out three-point bending loading and unloading for 3 times of circulation.
2. The composite strengthening method for improving the fatigue life and the permanent deformation resistance of a single leaf spring according to claim 1, wherein in the second step, the bending stress kept by the tool holder is 1000MPa to 1250 MPa.
3. The composite strengthening method for improving the fatigue life and the permanent deformation resistance of a single-piece spring according to claim 2, wherein the bending stress is 1100MPa to 1200 MPa.
4. The composite strengthening method for improving the fatigue life and permanent deformation resistance of a single leaf spring according to claim 1, wherein in the third step, the coarse pellets are cut steel wire pellets with the diameter of 0.8mm to 1.2mm, the cut steel wire pellets are subjected to a finishing and rounding treatment, the shot blasting strength is 0.30C to 0.35C, and the shot blasting time is 2min to 5 min.
5. The composite strengthening method for improving the fatigue life and permanent deformation resistance of a single leaf spring according to claim 4, wherein the coarse pellets are cut steel wire pellets with a diameter of 1.0mm, and the cut steel wire pellets are subjected to a finishing rounding treatment, and the shot strength is 0.32C-0.33C, and the shot blasting time is 3 min-4 min.
6. The composite strengthening method for improving the fatigue life and permanent deformation resistance of a single leaf spring according to claim 1, wherein in the fourth step, the fine shot is a steel wire cut shot with a diameter of 0.4mm to 0.6mm, and the steel wire cut shot is subjected to a finishing rounding treatment, the shot strength is 0.20C to 0.25C, and the shot blasting time is 3min to 6 min.
7. The composite strengthening method for improving the fatigue life and permanent deformation resistance of a single leaf spring according to claim 6, wherein the fine pellets are cut steel wire pellets with a diameter of 0.5mm, and the cut steel wire pellets are subjected to a finishing rounding treatment, and the shot strength is 0.22C-0.24C, and the shot blasting time is 4 min-5 min.
8. The composite strengthening method for improving the fatigue life and the permanent deformation resistance of the single-piece spring according to claim 1, wherein in the sixth step, the heating temperature is 180 ℃ to 220 ℃, and the bending stress of the three-point bending loading is 1100MPa to 1300 MPa.
9. The composite strengthening method for improving the fatigue life and permanent deformation resistance of a single-leaf spring according to claim 8, wherein the heating temperature is 210 ℃ and the bending stress of three-point bending loading is 1200MPa to 1250 MPa.
10. The composite strengthening method for improving the fatigue life and the permanent deformation resistance of the single leaf spring according to claim 1, wherein the tool clamp comprises a clamp base, a clamping arm and a force application gasket; the force application gasket is placed on the clamp base and used for supporting the bottom of the bending surface of the single leaf spring to be kept; the two clamping arms move to two ends of the single leaf spring along the horizontal direction and are used for clamping the single leaf spring which is subjected to bending deformation; the clamping arm and the force application gasket act together to keep the single leaf spring bent and deformed.
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| CN1607995A (en) * | 2001-12-26 | 2005-04-20 | 日本发条株式会社 | Leaf spring for vehicle and method of manufacturing the leaf spring |
| CN102189493A (en) * | 2011-04-22 | 2011-09-21 | 重庆红旗弹簧有限公司 | Reinforced stress shot blasting method and device |
| CN105728601A (en) * | 2014-12-11 | 2016-07-06 | 上海中国弹簧制造有限公司 | Manufacturing process for valve spring |
| JP2016156082A (en) * | 2015-02-26 | 2016-09-01 | 愛知製鋼株式会社 | Leaf spring and manufacturing method therefor |
| CN108747218A (en) * | 2018-06-02 | 2018-11-06 | 江苏翔鹰五金弹簧有限公司 | A kind of processing technology of arc spring |
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