Method for quickly establishing shot peening strengthening target strength saturation curve

Abstract

The invention belongs to the technical field of aircraft manufacturing, and discloses a method for quickly establishing a shot peening strengthening target strength saturation curve, which is used for improving the establishment efficiency of the target strength saturation curve and ensuring that the shot peening strength of the saturation curve is centered within a designed shot peening strength range by selecting proper air pressure and shot flow. The technical problems that the current saturation curve establishment efficiency is low, the shot blasting strength is close to the upper and lower limits of the designed shot blasting strength range, and the air pressure and the shot flow are unbalanced are solved.

Description

Technical Field

[0001] The invention belongs to the field of aircraft manufacturing-shot peening processing technology, and specifically relates to a method for quickly establishing a shot peening target strength saturation curve. Background Art

[0002] Shot peening refers to a process that uses a projectile with a certain kinetic energy to hit the surface of a metal part, creating pits on the surface of the part, causing plastic flow of the metal on the surface of the part, and thus generating a residual compressive stress layer. Shot peening can effectively improve the fatigue strength and stress corrosion resistance of metal parts. Shot peening intensity is an important control factor for the quality of shot peening of parts. If the shot peening intensity is too low, the parts will not meet the required fatigue resistance. If the shot peening intensity is too high, the ductility of the surface of the part will be reduced, reducing the fatigue strength. Therefore, a numerical range will be specified in the part design drawing as the design shot peening intensity range of the part.

[0003] The shot peening intensity can only be determined by the saturation curve. When designing the shot peening process for parts, the process personnel need to use the shot peening equipment to establish a saturation curve. The saturation curve is a curve of the relationship between the shot peening time and the ALMEN arc height value. The process of establishing the saturation curve is relatively complicated. It is necessary to peen at least four ALMEN test pieces with different shot peening times under the same equipment. Under the conditions of constant shot peening parameters such as air pressure, shot flow, shot peening medium, nozzle diameter, nozzle type, shot peening angle, and shot peening distance, the corresponding ALMEN arc height values ​​are obtained, and the saturation curve is drawn based on these data. When the shot peening time is doubled on the saturation curve, the point where the ALMEN arc height value increases by 10% is the saturation point. The ALMEN arc height value corresponding to the saturation point is the shot peening intensity of the saturation curve. The shot peening intensity of the established saturation curve must be within the design shot peening intensity range. Otherwise, it is necessary to adjust the shot peening parameters and re-establish the saturation curve until the shot peening intensity of the saturation curve is within the design shot peening intensity range. Only then can the shot peening parameters at the saturation point of the saturation curve be used as the shot peening parameters of the processed parts.

[0004] The establishment of the saturation curve is not a one-time thing. After the processing equipment is repaired, the shot peening pipeline is replaced, the shot peening pipeline is worn out after long-term use, etc., the performance of the shot peening equipment will change significantly and the original saturation curve will become invalid. The saturation point shot peening parameters will not be able to be used for processing parts, and the saturation curve needs to be re-established.

[0005] The establishment of the saturation curve is a process of continuously adjusting the shot peening parameters and establishing the saturation curve until the shot peening intensity of the saturation curve is within the designed shot peening intensity range. The key to establishing the saturation curve is to determine the shot peening parameters of the saturation curve. However, there is currently no systematic theoretical basis for determining the shot peening parameters of the saturation curve. Relying solely on the experience of process personnel to repeatedly adjust the shot peening parameters to establish the saturation curve has the following three problems:

[0006] (1) The efficiency of establishing the saturation curve is low, and long-term occupation of production equipment will seriously affect the production progress.

[0007] (2) Relying on experience to adjust the shot peening parameters cannot guarantee that the shot peening intensity is determined in the middle area of ​​the designed shot peening intensity range. When the shot peening intensity of the saturation curve is close to the upper and lower limits of the designed shot peening intensity range, the strength verification during part processing is likely to exceed the strength range, and the saturation curve has poor ability to adapt to changes in equipment performance, and the probability of saturation curve failure is greater.

[0008] (3) Unplanned adjustment of shot peening parameters. In order to meet the requirements of shot peening intensity, the balance between air pressure and shot flow rate is often not taken into account. If too large a flow rate is used to match too large a pressure for shot peening, the surface quality of the parts after shot peening will be poor. If too small a pressure is used to match too small a flow rate for shot peening, the shot peening efficiency will be extremely low, affecting production efficiency. Moreover, under the conditions of shot peening parameters close to the equipment limit, the equipment performance is unstable and there is a great risk of product quality.

[0009] Therefore, a method for quickly establishing a saturation curve for the target strength of shot peening is urgently needed to solve the current problems of low efficiency in establishing the saturation curve, shot peening intensity close to the upper and lower limits of the designed shot peening intensity range, and imbalance between air pressure and shot flow rate. Summary of the invention

[0010] The present invention is to solve the problems of low efficiency in establishing saturation curve, reliance on experience to adjust shot peening parameters, and unplanned adjustment of shot peening parameters in the current saturation curve establishment. A method for quickly establishing a saturation curve of target intensity of shot peening is proposed, and suitable air pressure and shot flow rate are selected to improve the efficiency of establishing the target intensity saturation curve, so as to ensure that the saturation curve shot peening intensity is centered within the designed shot peening intensity range.

[0011] In order to achieve the above invention objectives, the technical solutions adopted in this application are as follows:

[0012] A method for quickly establishing a shot peening target strength saturation curve comprises the following steps:

[0013] Step 1: Select the median of the air pressure and projectile flow rate within the adjustable range of the equipment as the reference air pressure and reference projectile flow rate, and obtain the reference supersaturated ALMEN arc height value by establishing a reference saturation curve;

[0014] Step 2: Select the upper and lower limit shot flow rates of the equipment, adjust the air pressure, shot peen the ALMEN test piece, record the respective ALMEN arc height values ​​under the upper and lower limit shot flow rates, and establish the high shot flow rate function curve and the low shot flow rate function curve;

[0015] Step 3: Using the high shot flow rate function curve and the low shot flow rate function curve, a first function region is established;

[0016] Step 4: When the performance of the equipment is changed, the reference air pressure and the reference shot flow rate are used to shot peen the ALMEN test piece, and the actual supersaturated ALMEN arc height value is obtained. The difference between the actual supersaturated ALMEN arc height value and the reference supersaturated ALMEN arc height value is used as the offset to correct the first function area, and the corrected first function area is the value range of the air pressure and the supersaturated ALMEN arc height value;

[0017] Step 5: Taking the middle value of the designed shot peening intensity range as the target shot peening intensity, taking 1.1 times the target shot peening intensity as the target supersaturated intensity, finding the middle value of the optional range of the target supersaturated intensity corresponding to the air pressure in the modified first function area as the target air pressure, and then determining the maximum supersaturated ALMEN arc height value, the minimum supersaturated ALMEN arc height value and the target supersaturated ALMEN arc height value in the optional range according to the target air pressure;

[0018] Step 6: According to the inverse relationship between the projectile flow rate and the super-saturated ALMEN arc height value, the target projectile flow rate corresponding to the target super-saturated ALMEN arc height value is obtained;

[0019] Step 7: Use the target air pressure and target shot flow rate to establish a pending saturation curve; determine whether the peening intensity of the pending saturation curve is centered within the designed peening intensity range. If so, the saturation curve is established; if not, the pending saturation curve is corrected until the target intensity saturation curve is obtained.

[0020] As a further solution of the present invention, it also includes a saturation curve failure judgment step: when the actual ALMEN arc height value obtained by strength verification does not meet the requirements of the design drawings, the saturation curve is invalid and the saturation curve needs to be re-established.

[0021] As a further solution of the present invention: The specific content of step 1 is: use the benchmark air pressure and the benchmark shot flow rate to establish a saturation curve as the benchmark saturation curve, the shot peening intensity of the benchmark saturation curve is the benchmark shot peening intensity, the time corresponding to the saturation point of the benchmark saturation curve is the benchmark saturation time, and three times the benchmark saturation time is called the benchmark super-saturation time. Use the benchmark super-saturation time to shot peen the ALMEN specimen, measure the arc height value of the ALMEN specimen, and record it as the benchmark super-saturated ALMEN arc height value.

[0022] As a further solution of the present invention: the specific content of step 2 is: within the range of shot flow within the adjustable range of the equipment, the upper limit is selected as the high shot flow rate, and the lower limit is selected as the low shot flow rate. Under the conditions of high shot flow rate and low shot flow rate, the reference supersaturation time is used to change the air pressure within the adjustable range of the equipment air pressure, and shot peening multiple ALMEN test pieces is performed to measure the arc height value of each ALMEN test piece as the supersaturated ALMEN arc height value. The air pressure is taken as the independent variable x and the supersaturated ALMEN arc height value is taken as the dependent variable y. In the same coordinate system, function curves of the air pressure x and the supersaturated ALMEN arc height value y under the conditions of high shot flow rate and low shot flow rate are fitted respectively, which are called the high shot flow rate function curve and the low shot flow rate function curve respectively. The high shot flow rate function curve and the low shot flow rate function curve are collectively referred to as the first function curve.

[0023] As a further solution of the present invention: the specific content of step 3 is: make a straight line segment parallel to the y-axis to connect the starting ends of the high projectile flow function curve and the low projectile flow function curve, and then make another straight line segment parallel to the y-axis to connect the ends of the high projectile flow function curve and the low projectile flow function curve. The two straight line segments and the high projectile flow function curve and the low projectile flow function curve form a closed area, and this closed area is called the first function area.

[0024] As a further solution of the present invention: the specific content of step 4 is: when it is necessary to establish a saturation curve, use the reference air pressure, the reference projectile flow rate, and the reference supersaturation time to shot peen the ALMEN test piece to obtain the actual supersaturated ALMEN arc height value, calculate the difference between the actual supersaturated ALMEN arc height value and the reference supersaturated ALMEN arc height value, use the difference as an offset, translate the first function area along the y-axis direction by the offset, and obtain a corrected first function area.

[0025] As a further solution of the present invention: Step 5 specifically includes: taking the middle value of the designed shot peening intensity range as the target shot peening intensity, taking 1.1 times the target shot peening intensity as the target supersaturation intensity, whose value is recorded as N, and drawing a straight line y=N to intersect the boundary of the modified first function region to obtain an intersection point X 1 and intersection point X 2 , the intersection point X 1 and intersection point X 2 The midpoint of the line connecting the two is recorded as point A, and the x coordinate value of point A is the target air pressure, and its value is recorded as K. Draw a straight line x = K to intersect with the boundary of the modified first function area, and get the intersection point Y 1 and intersection point Y 2 , the intersection point Y 1 and intersection point Y 2 The y-coordinate value of 1 and 2 ,y 2 >y 1.

[0026] As a further solution of the present invention: The specific content of step 6 is: under the condition of constant air pressure, the projectile flow rate is approximately inversely proportional to the supersaturated ALMEN arc height value. Therefore, the projectile flow rate is taken as the independent variable l, and the supersaturated ALMEN arc height value is taken as the dependent variable y. Using the intersection Y 1 and Y 2 The coordinate value of can be used to obtain a function in the form of y=kl+b, called the second function. The target supersaturation intensity is substituted into the second function as the y value to obtain the corresponding l value as the target projectile flow rate.

[0027] As a further solution of the present invention: in step 7, the specific content of the correction method is: calculate the difference △y between the target shot peening intensity and the shot peening intensity of the pending saturation curve, calculate the difference △y if the super-saturated ALMEN arc height value needs to be changed according to the slope k of the second function, and the corresponding shot flow difference △l that needs to be changed, adjust the target shot flow according to △l, and establish a pending corrected saturation curve with the target air pressure and the adjusted target shot flow. If the shot peening intensity of the pending corrected saturation curve is centered within the designed shot peening intensity range and meets expectations, the pending saturation curve is the target intensity saturation curve. If the shot peening intensity of the pending corrected saturation curve still does not meet expectations, adjust the target shot flow again according to the above method to establish the saturation curve until the shot peening intensity meets expectations.

[0028] As a further solution of the present invention: for a specific device, steps 1 to 3 only need to be performed once; when a new saturation curve needs to be established, only steps 4 to 7 need to be performed.

[0029] Compared with the prior art, the beneficial effects of this application are:

[0030] 1. The reference supersaturated ALMEN arc height value is obtained by establishing a reference saturation curve, and the reference supersaturated ALMEN arc height value is used as a yardstick to measure the performance of the equipment. When the equipment performance changes, the difference between the actual supersaturated ALMEN arc height value and the reference supersaturated ALMEN arc height value is used as the offset to correct the first function area, which can quickly compensate for the impact of the change in equipment performance on the first function area. Avoid blindly selecting shot peening parameters when establishing the pending saturation curve without understanding the changed equipment performance.

[0031] 2. The saturated curve shot peening intensity is obtained directly through the approximate conversion relationship of 1.1 times between the super-saturated ALMEN arc height value and the saturated curve shot peening intensity, which can save the process of establishing the saturation curve many times, greatly improve the establishment speed of the first function curve, and increase the determination speed of the target air pressure and the target projectile flow rate.

[0032] 3. First, determine the target air pressure and target shot flow rate based on the modified first function area to ensure that the shot peening intensity of the pending saturation curve is within the designed shot peening intensity range. Then adjust the target shot flow rate based on the second function, correct the shot peening intensity of the pending saturation curve to be centered within the designed shot peening intensity range, and obtain the pending modified saturation curve. This method of establishing the target intensity saturation curve is highly efficient and can ensure that the shot peening intensity of the saturation curve is centered within the designed shot peening intensity range. The strength verification during part processing is not easy to be too long, and the saturation curve has a good ability to adapt to changes in equipment performance.

[0033] 4. The modified first function area can fully display the relationship between the current equipment air pressure and shot flow rate and the supersaturated ALMEN arc height value. When selecting the target air pressure and target shot flow rate, the modified first function area can be used to comprehensively grasp all the air pressures and shot flow rates that may establish the target intensity saturation curve. Select the median of all air pressures as the target air pressure, and then determine the shot flow rate that matches the target air pressure according to the second function as the target shot flow rate. This parameter determination method ensures that the target air pressure and target shot flow rate are located in the middle of the adjustable parameter range of the equipment. The performance of the equipment is stable when it runs in the middle of the adjustable parameter range. This parameter determination method also well balances the relationship between the target air pressure and the target shot flow rate, and strikes a balance between the surface quality of the part and the efficiency of shot peening.

[0034] The present application is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0036] In the attached picture:

[0037] Figure 1 is the reference saturation curve of the present invention;

[0038] Figure 2 is the first functional area of ​​the present invention;

[0039] Figure 3 Modifying the first functional region for the present invention;

[0040] Figure 4 is the undetermined saturation curve of the present invention;

[0041] Figure 5 This is the to-be-determined corrected saturation curve of the present invention. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0043] like Figure 1-5 As shown, an embodiment of the present invention is shown. Assuming that the design shot peening intensity range of a certain part is 0.25mmA to 0.35mmA, a method for quickly establishing a target intensity saturation curve for shot peening is further described by taking a specific method of establishing a target intensity saturation curve for a certain device as an example:

[0044] The nozzle diameter of this equipment is 10mm, the nozzle type is a straight nozzle, and the shot peening medium is hard cast steel shot ASH230. The shot peening process of the parts requires a shot peening angle of 45° and a shot peening distance of 500mm. During the establishment of the saturation curve, the above shot peening parameters remain unchanged.

[0045] Step 1: The air pressure within the adjustable range of the equipment is 0.1MPa~0.45MPa, and the pellet flow rate is 6KG~14KG. Select the median and get the reference air pressure of 0.275MPa and the reference pellet flow rate of 10kg. Establish the reference saturation curve with the reference air pressure of 0.275MPa and the reference pellet flow rate of 10kg, such as Figure 1 The benchmark peening intensity is 0.231 mmA obtained by the benchmark saturation curve. The benchmark saturation time of the benchmark saturation curve is 7.30 s, and the benchmark supersaturation time is 21.9 s. The ALMEN test piece is shot peened with the benchmark supersaturation time of 21.9 s, and the arc height of the ALMEN test piece is measured, and the benchmark supersaturated ALMEN arc height is 0.256 mmA.

[0046] Step 2: Select the upper limit of 14KG as the high shot flow rate and the lower limit of 6KG as the low shot flow rate within the adjustable range of the equipment. Under the conditions of high shot flow rate of 14KG and low shot flow rate of 6KG, the shot peening time uses the benchmark supersaturation time of 21.9S. Increase the air pressure by 0.05MPa within the adjustable range of the equipment air pressure of 0.1MPa to 0.45MPa, and shot peen 8 ALMEN test pieces. Measure and record the arc height value of the ALMEN test piece as the supersaturated ALMEN arc height value. With air pressure as the independent variable x and supersaturated ALMEN arc height value as the dependent variable y, in the same coordinate system, use a quadratic polynomial to fit the function curve of air pressure x and supersaturated ALMEN arc height value y under high shot flow and low shot flow conditions. The high shot flow function curve is:

[0047] y=-1.4143x2 +1.2269x-0.0086, the low projectile flow function curve is:

[0048] y=-2.0024x 2 +1.7354x-0.0116, collectively known as the first function curve.

[0049] Step 3: Make a straight line segment parallel to the y-axis to connect the beginning of the high-shot flow function curve and the low-shot flow function curve, and then make another straight line segment parallel to the y-axis to connect the ends of the high-shot flow function curve and the low-shot flow function curve. The two straight lines and the high-shot flow function curve and the low-shot flow function curve form a closed area, which is called the first function area. Figure 2 .

[0050] Step 4: When a saturation curve is required, the ALMEN test piece is shot peened using a reference air pressure of 0.275 MPa, a reference shot flow rate of 10 kg, and a reference supersaturation time of 21.9 S, and the actual supersaturated ALMEN arc height value is 0.275 mmA. The difference between the actual supersaturated ALMEN arc height value of 0.275 and the reference supersaturated ALMEN arc height value of 0.256 mmA is calculated, and the difference of 0.019 mmA is used as the offset. The first function area is translated along the y-axis direction by the offset to obtain the corrected first function area.

[0051] Step 5: Set the middle value of the designed shot peening intensity range, 0.30 mmA, as the target shot peening intensity. Set the target shot peening intensity, 1.1 times, as the target supersaturation intensity, with a value of 0.33 mmA. Draw a straight line y = 0.33 that intersects the boundary of the modified first function region to obtain the intersection point X 1 and intersection point X 2 . Set the intersection point X 1 and intersection point X 2 The midpoint of the line connecting the two is recorded as point A. The x coordinate of point A is the target air pressure, which is 0.345 MPa. Draw a straight line x=0.345 and intersect the boundary of the modified first function area to obtain the intersection point Y 1 and intersection point Y 2 ,like Figure 3 . Set the intersection point Y 1 and intersection point Y 2 The y-coordinate value of 1 and 2 ,y 2 >y 1 .y 1 is 0.235, y 2 It is 0.385.

[0052] Step 6: Because the air pressure remains constant, the shot flow rate is approximately inversely proportional to the supersaturated ALMEN arc height. Therefore, the shot flow rate is taken as the independent variable l, and the supersaturated ALMEN arc height is taken as the dependent variable y. 1 and intersection point Y 2 The coordinate value of is used to obtain the second function y=-0.01875l+0.4975. Substituting the target supersaturation intensity y=0.33mmA into the second function, the corresponding projectile flow rate is l=8.93KG, that is, the target projectile flow rate is 8.93KG.

[0053] Step 7: Use the target air pressure of 0.345MPa and the target projectile flow rate of 8.93KG to establish the undetermined saturation curve, such as Figure 4 The shot peening intensity of the undetermined saturation curve is 0.286 mmA, which is not centered within the designed shot peening intensity range and still needs to be adjusted. Go to step 8.

[0054] Step 8: The difference △y between the target shot peening intensity 0.30mmA and the undetermined saturation curve shot peening intensity 0.286mmA is 0.014mmA. The slope of the second function is -0.01875, so the change in the supersaturated ALMEN arc height of 0.014mmA requires a corresponding change in the shot flow rate difference △l of -0.75MPa. Therefore, the target shot flow rate is adjusted to 8.18KG. The undetermined corrected saturation curve is established with the target air pressure of 0.345MPa and the target shot flow rate of 8.18KG, as shown in Figure 5 The peening intensity of the undetermined modified saturation curve is 0.298 mmA, which is in the middle of the designed peening intensity range and meets expectations. The undetermined saturation curve is the target intensity saturation curve, and the saturation curve is established.

[0055] So far, the purpose of the present invention has been achieved.

[0056] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for quickly establishing a target strength saturation curve for shot peening, characterized in that: The steps include: Step 1: Select the median of the air pressure and projectile flow rate within the adjustable range of the equipment as the reference air pressure and reference projectile flow rate, and obtain the reference supersaturated ALMEN arc height value by establishing a reference saturation curve; Step 2: Select the upper and lower limit shot flow rates of the equipment, adjust the air pressure, shot peen the ALMEN test piece, record the respective ALMEN arc height values ​​under the upper and lower limit shot flow rates, and establish the high shot flow rate function curve and the low shot flow rate function curve; Step 3: Using the high shot flow rate function curve and the low shot flow rate function curve, a first function region is established; Step 4: When the performance of the equipment is changed, the reference air pressure and the reference shot flow rate are used to shot peen the ALMEN test piece, and the actual supersaturated ALMEN arc height value is obtained. The difference between the actual supersaturated ALMEN arc height value and the reference supersaturated ALMEN arc height value is used as the offset to correct the first function area, and the corrected first function area is the value range of the air pressure and the supersaturated ALMEN arc height value; Step 5: Taking the middle value of the designed shot peening intensity range as the target shot peening intensity, taking 1.1 times the target shot peening intensity as the target supersaturated intensity, finding the middle value of the optional range of the target supersaturated intensity corresponding to the air pressure in the modified first function area as the target air pressure, and then determining the maximum supersaturated ALMEN arc height value, the minimum supersaturated ALMEN arc height value and the target supersaturated ALMEN arc height value in the optional range according to the target air pressure; Step 6: According to the inverse relationship between the projectile flow rate and the super-saturated ALMEN arc height value, the target projectile flow rate corresponding to the target super-saturated ALMEN arc height value is obtained; Step 7: Use the target air pressure and target shot flow rate to establish a pending saturation curve; determine whether the peening intensity of the pending saturation curve is centered within the designed peening intensity range. If so, the saturation curve is established; if not, the pending saturation curve is corrected until the target intensity saturation curve is obtained.

2. A method for quickly establishing a target strength saturation curve for shot peening according to claim 1, characterized in that: It also includes a saturation curve failure judgment step: when the actual ALMEN arc height value obtained by strength verification does not meet the requirements of the design drawings, the saturation curve is invalid and the saturation curve needs to be re-established.

3. The method for quickly establishing a shot peening target strength saturation curve according to claim 1, characterized in that: The specific content of step 1 is: use the reference air pressure and the reference shot flow rate to establish a saturation curve as the reference saturation curve, the shot peening intensity of the reference saturation curve is the reference shot peening intensity, the time corresponding to the saturation point of the reference saturation curve is the reference saturation time, three times the reference saturation time is called the reference super-saturation time, the ALMEN test piece is shot peened using the reference super-saturation time, the arc height value of the ALMEN test piece is measured, and recorded as the reference super-saturated ALMEN arc height value.

4. A method for quickly establishing a shot peening target strength saturation curve according to claim 2, characterized in that: The specific content of step 2 is: within the range of shot flow within the adjustable range of the equipment, select the upper limit as the high shot flow rate, select the lower limit as the low shot flow rate, under the conditions of high shot flow rate and low shot flow rate, use the reference supersaturation time, change the air pressure within the adjustable range of the equipment air pressure, shot peen multiple ALMEN test pieces, measure the arc height value of each ALMEN test piece, as the supersaturated ALMEN arc height value, take the air pressure as the independent variable x, and the supersaturated ALMEN arc height value as the dependent variable y, and fit the function curves of the air pressure x and the supersaturated ALMEN arc height value y under the conditions of high shot flow rate and low shot flow rate in the same coordinate system, which are respectively called the high shot flow rate function curve and the low shot flow rate function curve, and the high shot flow rate function curve and the low shot flow rate function curve are collectively referred to as the first function curve.

5. A method for quickly establishing a shot peening target strength saturation curve according to claim 4, characterized in that: The specific content of step 3 is: make a straight line segment parallel to the y-axis connecting the starting ends of the high projectile flow function curve and the low projectile flow function curve, and then make another straight line segment parallel to the y-axis connecting the ends of the high projectile flow function curve and the low projectile flow function curve. The two straight line segments and the high projectile flow function curve and the low projectile flow function curve form a closed area, and this closed area is called the first function area.

6. A method for quickly establishing a target strength saturation curve for shot peening according to claim 5, characterized in that: The specific content of step 4 is: when it is necessary to establish a saturation curve, use the reference air pressure, the reference shot flow rate, and the reference supersaturation time to shot peen the ALMEN test piece to obtain the actual supersaturated ALMEN arc height value, calculate the difference between the actual supersaturated ALMEN arc height value and the reference supersaturated ALMEN arc height value, use the difference as an offset, translate the first function area along the y-axis direction by the offset, and obtain a corrected first function area.

7. A method for quickly establishing a shot peening target strength saturation curve according to claim 6, characterized in that: The specific content of step 5 is: take the middle value of the designed shot peening intensity range as the target shot peening intensity, take 1.1 times the target shot peening intensity as the target supersaturation intensity, and record its value as N. Draw a straight line y=N to intersect with the boundary of the modified first function area to obtain intersection X1 and intersection X2. Record the midpoint of the line connecting intersection X1 and intersection X2 as point A. The x-coordinate value of point A is the target air pressure, and its value is recorded as K. Draw a straight line x=K to intersect with the boundary of the modified first function area to obtain intersection Y1 and intersection Y2. Record the y-coordinate values ​​of intersection Y1 and intersection Y2 as y1 and y2, and y2>y1.

8. A method for quickly establishing a target strength saturation curve for shot peening according to claim 7, characterized in that: The specific content of step 6 is: under the condition of constant air pressure, the projectile flow rate is approximately inversely proportional to the supersaturated ALMEN arc height value. Therefore, taking the projectile flow rate as the independent variable l and the supersaturated ALMEN arc height value as the dependent variable y, a function of the form of y=kl+b can be obtained using the coordinate values ​​of the intersection points Y1 and Y2, which is called the second function. The target supersaturated intensity is substituted into the second function as the y value to obtain the corresponding l value as the target projectile flow rate.

9. A method for quickly establishing a shot peening target strength saturation curve according to claim 8, characterized in that: In step 7, the specific content of the correction method is: calculate the difference △y between the target shot peening intensity and the shot peening intensity of the pending saturation curve, calculate the difference △y if the super-saturated ALMEN arc height value needs to be changed according to the slope k of the second function, and the corresponding shot flow difference △l needs to be changed, adjust the target shot flow according to △l, and establish the pending corrected saturation curve with the target air pressure and the adjusted target shot flow. If the shot peening intensity of the pending corrected saturation curve is centered within the design shot peening intensity range and meets expectations, the pending saturation curve is the target intensity saturation curve. If the shot peening intensity of the pending corrected saturation curve still does not meet expectations, adjust the target shot flow again according to the above method to establish the saturation curve until the shot peening intensity meets expectations.

10. A method for quickly establishing a shot peening target strength saturation curve according to any one of claims 1 to 9, characterized in that: For a specific device, steps 1 to 3 only need to be performed once; when a new saturation curve needs to be established, only steps 4 to 7 need to be performed.

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