A projectile-type ultrasonic impact strengthening device for Almen test piece and its use method

Abstract

The present invention belongs to the part surface treatment technology, and relates to a projectile-type ultrasonic impact strengthening device for an Almen test piece and a method for using the device. The device comprises a horn (1), a cavity base (2), an adjustable bracket (3), a fuselage bracket (4), a support plate (5), a lower pressure plate (6), a test piece fixture (7), and a projectile-shaped cavity groove (8); the Almen test piece fixture of the present invention adopts a method of clamping and fixing at both ends to avoid structural interference with the projectile-shaped cavity groove by fixing with screws. An ultrasonic source is used to excite the movement of a hard projectile in the projectile-shaped cavity groove, so that the projectile impacts the surface of the Almen test piece at high speed under ultrasonic excitation, thereby causing elastic-plastic deformation of the surface and achieving surface strengthening. The present invention obtains a suitable impact force and impact uniformity by reasonably designing the shape and size of the projectile-shaped cavity groove, and matching the appropriate projectile size and number, thereby achieving the optimal strengthening effect of the Almen test piece.

Description

Technical Field

[0001] The invention belongs to a part surface treatment technology and relates to a projectile-type ultrasonic impact strengthening device for an Almen test piece and a use method thereof. Background Art

[0002] As a new type of surface strengthening technology, shot-type ultrasonic impact strengthening has multiple advantages such as high energy, high efficiency and no pollution. Shot peening intensity is an important indicator to measure the surface strengthening effect. The most widely used shot peening strength measurement in engineering is the Almen test piece. This method has the advantages of being fast, simple, and having wide structural adaptability, and is widely used. Traditional shot peening strengthening technology uses compressed gas to drive the projectile to move at high speed, impacting the surface of the test piece, causing a residual compressive stress layer on the surface of the test piece to form an arc height. The difference is that ultrasonic impact strengthening uses an ultrasonic source to amplify the amplitude of the ultrasonic source through a variable amplitude rod, and drives the projectile to perform high-speed, Brownian motion, thereby achieving impact on the surface of the test piece and generating an arc height. Since the tool head size of the amplitude transformer (20mm×15mm) is significantly smaller than the width (20mm) and length (76mm) of the Almen specimen, the traditional method uses the regional overlap method to strengthen the entire Almen specimen surface. However, this method has disadvantages such as low efficiency and repeated impact in the overlap area, which makes it difficult to reflect the ultrasonic impact strengthening process of real parts. Therefore, it is urgent to increase the area of ​​the upper opening plane by reasonably designing the projectile cavity groove, thereby reducing the number of overlaps.

[0003] In addition, the current shot peening technology has detailed regulations on the test method of shot peening strength in the aviation standard HB / Z 26 "Parts Shot Peening". This method uses 4 screws to fix the Almen test piece. However, this method is not suitable for projectile ultrasonic impact strengthening technology because the 4 screws will cause structural interference to the projectile cavity. If the projectile cavity completely covers the screws, on the one hand, it is easy to cause the projectile to leak, and on the other hand, the raised screws will interfere with the movement trajectory of the projectile inside the projectile cavity, seriously affecting the strengthening effect. If the screws and their adjacent areas are not strengthened, the structure of the projectile cavity will become more complicated, and the movement trajectory of the projectile will also be disturbed, which will seriously affect the strengthening effect. Summary of the invention

[0004] The purpose of the present invention is to propose a projectile-type ultrasonic impact strengthening device for an Almen specimen and a method of using the device, so as to realize ultrasonic impact strengthening of the Almen specimen, overcome the adverse effects of interference of the screw structure, increase the area of ​​single strengthening, reduce the number of overlaps, and thus improve the processing efficiency.

[0005] The technical solution of the present invention is:

[0006] A projectile type ultrasonic impact strengthening device for an Almen test piece comprises a horn 1, a cavity base 2, an adjustable bracket 3, a body bracket 4, a support plate 5, a lower pressure plate 6, a test piece fixture 7, and a projectile cavity groove 8; wherein the cavity base 2 and the adjustable bracket 3 are fixed on the body bracket 4, the cavity base 2 is in front of the adjustable bracket 3, and are positioned by positioning pins respectively; the lower pressure plate 6 is located on the upper part of the support plate 5, and the right end is placed in the middle groove of the support plate 5, and is connected and fixed by the left end of the adjustable bracket 3; the Almen test piece 9 is fixed in the test piece groove 703 of the test piece fixture 7, the projectile cavity groove 8 is fixed on the cavity base 2, the tool head at the upper end of the horn 1 passes through the lower opening plane 802 of the projectile cavity groove 8, and the lower surface of the Almen test piece 9 contacts the upper opening plane 801 of the projectile cavity groove 8.

[0007] The upper opening plane 801 of the projectile-shaped cavity groove 8 is a rectangle, and its length m is 0.5 to 1.0 mm smaller than the width of the Almen test piece, and its width is L; the lower opening plane 802 of the projectile-shaped cavity groove 8 is a square, and its side length is l. The transition section 803 between the upper opening plane 801 and the lower opening plane 802 is an inclined plane, and the angle between the inclined plane and the normal direction of the upper opening plane 801 is α, and the height difference between the upper opening plane 801 and the lower opening plane 802 is h.

[0008] The upper plane of the tool head at the upper end of the horn 1 is parallel to the lower opening plane 802, and the height difference between the two is Δh.

[0009] The adjustable bracket 3 is composed of a vertical support plate 301, an inclined support plate 302, a guide rail 303, a top plate 304, a slider 305, a screw 306 and a knob 307; the vertical support plate 301 is fixed on the fuselage bracket 4, the lower end of the inclined support plate 302 is connected and fixed to the fuselage bracket 4, and the upper end is connected and fixed to the vertical support plate 301; two parallel guide rails 303 are fixedly installed on one side of the vertical support plate 301, and a top plate 304 is provided above the guide rails 303 to be connected and fixed to the vertical support plate 301; the slider 305 is located between the two parallel guide rails 303 and can move up and down along the guide rails 303, and the groove on the upper part of the slider 305 is connected to the lower part of the screw 306; the screw 306 is inserted into the threaded hole in the center of the top plate 304 and is connected to the knob 307, and the screw 306 and the slider 305 can be moved up and down by rotating the knob 307.

[0010] The test piece fixture 7 is composed of a bottom plate 701, two end fixtures 702 and a test piece slot 703; the test piece slot 703 is located in the center of the bottom plate 701, and the two end fixtures 702 and the bottom plate 701 are fixedly connected to press and fix the Almen test piece 9.

[0011] The length of the test strip slot 703 is consistent with the length of the bottom plate 701 . The length, width and depth of the test strip slot 703 are respectively consistent with the length, width and thickness of the Almen test strip 9 . The length of the bottom plate 701 is 0.2 to 1.0 mm smaller than the length of the Almen test strip 9 .

[0012] The material of the projectile-shaped cavity (8) is resin.

[0013] A method for using a projectile-type ultrasonic impact strengthening device for an Almen specimen comprises the following steps:

[0014] (1) According to the requirements of the parts drawing, select a projectile with a diameter of d, 0.6mm≤d≤2mm;

[0015] (2) placing the Almen test piece 9 in the test piece slot 703 of the test piece fixture 7, and connecting and fixing the two end fixtures 702 and the bottom plate 701 by screws, thereby pressing and fixing the Almen test piece 9;

[0016] (3) The tool head at the upper end of the horn 1 is passed through the lower opening plane 802 of the projectile cavity groove 8. When the projectile diameter is 0.6 mm ≤ d ≤ 1 mm, 0 ≤ Δh ≤ 0.5 mm; when the projectile diameter is 1 mm < d ≤ 2 mm, 0 ≤ Δh ≤ 1 mm;

[0017] (4) Place N number of pellets into the pellet cavity 8, rotate the knob 307, and move the screw 306, the slider 305, the lower pressing plate 6, the support plate 5, and the specimen fixture 7 with the Almen specimen 9 fixed thereon downward together, so that the lower surface of the Almen specimen 9 contacts the upper opening plane 801, and the gap between the two does not exceed 0.1 mm;

[0018] (5) Turn on the power supply, and the tool head drives the projectile to perform high-speed Brownian motion and hit the surface of the Almen test piece. When it reaches 10 to 60 seconds, turn off the power supply;

[0019] (6) Push the lower pressing plate 6 to slide along the length direction of the middle groove so that the upper opening plane 801 is aligned with the unstrengthened area of ​​the Almen test piece, and repeat step 5;

[0020] (7) When the entire surface of the Almen test piece 9 is struck by the projectile, rotate the knob 307 to move the screw 306, the slider 305, the lower pressure plate 6, the support plate 5, and the test piece fixture 7 on which the Almen test piece 9 is fixed upward together, loosen the screws, remove the Almen test piece, and use a digital micrometer to measure the arc height value of the Almen test piece 9.

[0021] The relationship between the shot peening intensity I specified in the part drawing and the shot diameter d, the number of shots N, the height difference Δh, the height difference h between the upper opening plane (801) and the lower opening plane 802, the width L of the upper opening plane 801, and the side length l of the lower opening plane 802 is as follows:

[0022]

[0023] Almen test piece 9 meets the requirements of type A and type C test pieces in the aviation standard HB / Z26 "Shot Peening of Parts".

[0024] The advantages of the present invention are:

[0025] (1) Since the area of ​​the Almen specimen is larger than the area of ​​the tool head of the horn, the area of ​​the upper opening plane is increased through the design of the projectile cavity, thereby increasing the area of ​​single strengthening and reducing the number of overlaps, thereby improving the processing efficiency. However, increasing the upper opening area of ​​the projectile cavity groove will change the movement trajectory of the internal projectile, which will affect the impact force of the projectile on the one hand and the uniformity of the projectile's impact on the surface of the Almen specimen on the other hand. Therefore, the shape and size of the projectile cavity groove must be reasonably designed, and the appropriate projectile size and number must be matched to obtain the appropriate impact force and impact uniformity, thereby achieving the optimal strengthening effect of the Almen specimen.

[0026] (2) The Almen test piece fixture of the present invention adopts a method of clamping and fixing at both ends, thereby avoiding structural interference with the projectile cavity groove caused by fixing with four screws.

[0027] (3) This method consumes only a small amount of shot (10 to 100 shots), which is far less than traditional shot peening, resulting in lower processing costs, less dust, and less noise.

[0028] (4) Since the ultrasonic frequency is as high as 20-25 kHz and the resonance frequency of the horn is as high as 18-21 kHz, the surface strengthening processing efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the whole device

[0030] Figure 2 Turbine disc assembly diagram

[0031] Figure 3 Schematic diagram of the assembly of the closed projectile cavity

[0032] Figure 4 Schematic diagram of the structure of the test piece fixture 7

[0033] Among them: 1-amplifier, 2-cavity base, 3-adjustable bracket, 4-fuselage bracket, 5-support plate, 6-lower pressure plate, 7-test piece fixture, 8-projectile cavity groove, 9-Almen test piece, 301-vertical support plate, 302-oblique support plate, 303-slide rail, 304-top plate, 305-slider, 306-screw, 307-knob, 701-bottom plate, 702-clamps at both ends and 703-test piece groove, 801-upper opening plane, 802-lower opening plane DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with the accompanying drawings:

[0035] like Figure 1 , Figure 2 As shown, a projectile ultrasonic impact strengthening device for Almen test piece includes a horn 1, a cavity base 2, an adjustable bracket 3, a fuselage bracket 4, a support plate 5, a lower pressure plate 6, a test piece fixture 7, a projectile cavity groove 8 and an Almen test piece 9. The cavity base 2 is located above the fuselage bracket 4 and in front of the adjustable bracket 3, is positioned by a positioning pin, and is connected and fixed to the fuselage bracket 4 by a screw. The adjustable bracket 3 is located above the fuselage bracket 4, and is positioned by a positioning pin and fixed by a screw.

[0036] The adjustable bracket 3 is composed of a vertical support plate 301, an inclined support plate 302, a slide rail 303, a top plate 304, a slider 305, a screw 306 and a knob 307. The vertical support plate 301 is located above the fuselage support 4 and is fixed by screws. The lower end of the inclined support plate 302 is connected and fixed to the fuselage support 4, and the upper end is connected and fixed to the vertical support plate 301. Two parallel guide rails 303 are installed on one side of the vertical support plate 301 and are connected and fixed by screws. There is a top plate 304 above the guide rails 303, which is connected and fixed to the vertical support plate 301 by screws. The slider 305 is located between the two parallel guide rails 303 and can move up and down along the guide rails 303. The groove on the upper part of the slider 305 is connected to the lower part of the screw 306. The screw rod 306 is inserted into the threaded hole in the center of the top plate 304 and connected to the knob 307 . The screw rod 306 and the slider 305 can be moved up and down by rotating the knob 307 .

[0037] The lower pressing plate 6 is located on the upper part of the support plate 5, and the right end of the lower pressing plate 6 is placed in the middle groove of the support plate 5. The lower end of the slider 305 is connected to the upper right end of the support plate 5 and fixed by screws, so that the lower pressing plate 6 is pressed and fixed between the support plate 5 and the slider 305, and can only slide along the length direction of the middle groove. The upper part of the test piece fixture 7 is connected and fixed to the left end of the lower pressing plate 6 by screws. Figure 4 As shown, the test piece fixture 7 is composed of a base plate 701, two end fixtures 702 and a test piece slot 703. The test piece slot 703 is located in the center of the base plate, and the length of the test piece slot 703 is consistent with the length of the base plate 701. The length, width and depth of the test piece slot 703 are respectively consistent with the length, width and thickness of the Almen test piece 9. The length of the base plate 701 is 0.2 to 1.0 mm smaller than the length of the Almen test piece 9. The two end fixtures 702 and the base plate 701 are fixedly connected by screws to press and fix the Almen test piece 9. The projectile cavity slot 8 is located on the top of the cavity base 2 and is fixed by screws. As shown Figure 3As shown, the upper opening plane 801 of the projectile-shaped cavity groove 8 is a rectangle, the length m of the upper opening plane 801 is 0.5 to 1.0 mm smaller than the width of the Almen test piece, the width of the upper opening plane 801 is L, the lower opening plane 802 of the projectile-shaped cavity groove 8 is a square, the side length is l, the transition section 803 between the upper opening plane 801 and the lower opening plane 802 is an inclined plane, the angle between the inclined plane and the normal direction of the upper opening plane 801 is α, the height difference between the upper opening plane 801 and the lower opening plane 802 is h, the tool head at the upper end of the amplitude transformer 1 passes through the lower opening plane 802, the upper plane of the tool head at the upper end of the amplitude transformer 1 is parallel to the lower opening plane 802, and the height difference between the two is Δh.

[0038] A method for using a projectile-type ultrasonic impact strengthening device for an Almen test piece,

[0039] (1) According to the requirements of the parts drawing, select a projectile with a diameter of d, 0.6mm≤d≤2mm.

[0040] (2) The Almen test piece 9 is placed in the test piece slot 703 of the test piece fixture 7, and the two end fixtures 702 and the bottom plate 701 are connected and fixed by screws, so that the Almen test piece 9 is pressed and fixed.

[0041] (3) The tool head at the upper end of the horn 1 is passed through the lower opening plane 802 of the projectile cavity 8. When the projectile diameter is 0.6 mm ≤ d ≤ 1 mm, then 0 ≤ Δh ≤ 0.5 mm; when the projectile diameter is 1 mm < d ≤ 2 mm, then 0 ≤ Δh ≤ 1 mm.

[0042] (4) Place N number of pellets into the pellet cavity 8. Rotate the knob 307 to move the screw 306, the slider 305, the lower pressing plate 6, the support plate 5, and the fixture 7 with the Almen test piece 9 fixed thereon downward together, so that the lower surface of the Almen test piece 9 contacts the upper opening plane 801, and the gap between the two does not exceed 0.1 mm.

[0043] (5) Turn on the power supply, and the tool head drives the projectile to perform high-speed Brownian motion and hit the surface of the Almen test piece. When the time t is reached, turn off the power supply.

[0044] (6) Push the lower pressing plate 6 to slide along the length direction of the middle groove so that the upper opening plane 801 is aligned with the unstrengthened area of ​​the Almen test piece, and repeat step (5).

[0045] (7) When the entire surface of the Almen test piece is struck by the projectile, the knob 307 is rotated to move the screw 306, the slider 305, the lower pressure plate 6, the support plate 5, and the fixture 7 on which the Almen test piece 9 is fixed downward together, the screws are loosened, the Almen test piece is removed, and the arc height value of the Almen test piece 9 is measured using a digital micrometer.

[0046] The relationship between the shot peening intensity I specified in the part drawing and the shot diameter d, the number of shots N, the height difference Δh, the height difference h between the upper opening plane 801 and the lower opening plane 802, the width L of the upper opening plane 801, and the side length l of the lower opening plane 802 is as follows:

[0047]

[0048] The Almen test piece meets the requirements of the C-type test piece in the aviation standard HB / Z26 "Shot Peening of Parts".

[0049] The working principle of the present invention is:

[0050] Ultrasonic waves have the advantages of high frequency, high energy, and high power density, and are one of the ideal power sources for high-energy surface strengthening. Therefore, the present invention uses an ultrasonic source to excite the movement of hard projectiles in the projectile cavity groove, so that the projectiles impact the surface of the Almen test piece at high speed under ultrasonic excitation, thereby causing elastic-plastic deformation of the surface and achieving surface strengthening. Since the area of ​​the Almen test piece is larger than the area of ​​the tool head of the horn, the upper opening area of ​​the projectile cavity groove must be increased, which will change the movement trajectory of the internal projectile, on the one hand affecting the impact force of the projectile, and on the other hand affecting the uniformity of the impact of the projectile on the surface of the Almen test piece. Therefore, the shape and size of the projectile cavity groove must be reasonably designed, and the appropriate projectile size and number must be matched to obtain the appropriate impact force and impact uniformity, thereby achieving the optimal strengthening effect of the Almen test piece.

[0051] The Almen test piece fixture of the present invention adopts a method of clamping and fixing at both ends to avoid structural interference with the projectile cavity groove by screw fixing. If screw fixing is adopted, if the projectile cavity groove completely covers the screw, it is easy to cause projectile leakage on the one hand, and on the other hand, the protruding screw will interfere with the projectile movement trajectory inside the projectile cavity groove, seriously affecting the strengthening effect. If the screw and its adjacent area are not strengthened, the structure of the projectile cavity groove will become more complicated, and the projectile movement trajectory will also be disturbed, thereby seriously affecting the strengthening effect.

[0052] Embodiment 1:

[0053] A projectile type ultrasonic impact strengthening device for Almen test piece, the device comprises a horn 1, a cavity base 2, an adjustable bracket 3, a fuselage bracket 4, a support plate 5, a lower pressure plate 6, a test piece fixture 7, a projectile cavity groove 8 and an Almen test piece 9. The cavity base 2 is located above the fuselage bracket 4 and in front of the adjustable bracket 3, is positioned by a positioning pin, and is connected and fixed to the fuselage bracket 4 by a screw. The adjustable bracket 3 is located above the fuselage bracket 4, and is positioned by a positioning pin and fixed by a screw.

[0054] The adjustable bracket 3 is composed of a vertical support plate 301, an inclined support plate 302, a slide rail 303, a top plate 304, a slider 305, a screw 306 and a knob 307. The vertical support plate 301 is located above the fuselage support 4 and is fixed by screws. The lower end of the inclined support plate 302 is connected and fixed to the fuselage support 4, and the upper end is connected and fixed to the vertical support plate 301. Two parallel guide rails 303 are installed on one side of the vertical support plate 301 and are connected and fixed by screws. There is a top plate 304 above the guide rails 303, which is connected and fixed to the vertical support plate 301 by screws. The slider 305 is located between the two parallel guide rails 303 and can move up and down along the guide rails 303. The groove on the upper part of the slider 305 is connected to the lower part of the screw 306. The screw rod 306 is inserted into the threaded hole in the center of the top plate 304 and connected to the knob 307 . The screw rod 306 and the slider 305 can be moved up and down by rotating the knob 307 .

[0055] The lower pressing plate 6 is located at the upper part of the support plate 5, and the right end of the lower pressing plate 6 is placed in the middle groove of the support plate 5. The lower end of the slider 305 is connected to the upper right end of the support plate 5 and fixed by screws, and the lower pressing plate 6 is pressed and fixed between the support plate 5 and the slider 305, and can only slide along the length direction of the middle groove. The upper part of the test piece fixture 7 is connected and fixed to the left end of the lower pressing plate 6 by screws. The test piece fixture 7 consists of a base plate 701, two end fixtures 702 and a test piece groove 703. The test piece groove 703 is located in the center of the base plate, and the length of the test piece groove 703 is consistent with the length of the base plate 701. The length, width and depth of the test piece groove 703 are respectively consistent with the length, width and thickness of the Almen test piece 9. The length of the base plate 701 is 1.0 mm less than the length of the Almen test piece 9, and the two end fixtures 702 and the base plate 701 are fixedly connected by screws to press and fix the Almen test piece 9. The projectile cavity groove 8 is located on the cavity base 2 and fixed by screws. The upper opening plane 801 of the projectile cavity groove 8 is rectangular, the length m of the upper opening plane 801 is 1.0 mm smaller than the width of the Almen test piece, the width of the upper opening plane 801 is L, the lower opening plane 802 of the projectile cavity groove 8 is square, the side length is l, the transition section 803 between the upper opening plane 801 and the lower opening plane 802 is an inclined plane, the angle between the inclined plane and the normal direction of the upper opening plane 801 is α, the height difference between the upper opening plane 801 and the lower opening plane 802 is h, the tool head at the upper end of the horn 1 passes through the lower opening plane 802, the upper plane of the tool head at the upper end of the horn 1 is parallel to the lower opening plane 802, and the height difference between the two is Δh.

[0056] A method for using a projectile-type ultrasonic impact strengthening device for an Almen test piece,

[0057] (1) According to the requirements of the parts drawing, select a projectile with a diameter of d = 2 mm.

[0058] (2) The Almen test piece 9 is placed in the test piece slot 703 of the test piece fixture 7, and the two end fixtures 702 and the bottom plate 701 are connected and fixed by screws, so that the Almen test piece 9 is pressed and fixed.

[0059] (3) The tool head at the upper end of the amplitude transformer 1 passes through the lower opening plane 802 of the projectile-shaped cavity groove 8. The upper plane of the tool head at the upper end of the amplitude transformer 1 is parallel to the lower opening plane 802, and the height difference between the two is Δh=1 mm.

[0060] (4) Place N number of pellets into the pellet cavity 8. Rotate the knob 307 to move the screw 306, the slider 305, the lower pressing plate 6, the support plate 5, the Almen test piece fixing fixture 7 and the Almen test piece 9 downward together, so that the lower surface of the Almen test piece 9 contacts the upper opening plane 801, and the gap between the two is 0.1 mm.

[0061] (5) Turn on the power supply, and the tool head drives the projectile to perform high-speed Brownian motion and hit the surface of the Almen test piece. When the time reaches 15 seconds, turn off the power supply.

[0062] (6) Push the lower pressing plate 6 to slide along the length direction of the middle groove so that the upper opening plane 801 is aligned with the unstrengthened area of ​​the Almen test piece, and repeat step (5).

[0063] (7) When the entire surface of the Almen test piece is struck by the projectile, the knob 307 is rotated to move the screw 306, the slider 305, the lower pressure plate 6, the support plate 5, the Almen test piece fixing fixture 7 and the Almen test piece upward together, the screws are loosened, the Almen test piece is removed, and the 9-arc height value of the Almen test piece is measured using a digital micrometer.

[0064] A method for using a shot-type ultrasonic impact strengthening device for an Almen test piece, wherein the relationship between the shot peening intensity I and the shot diameter d, the number of shots N, the height difference Δh, the height difference h between the upper opening plane 801 and the lower opening plane 802, the width L of the upper opening plane 801, and the side length l of the lower opening plane 802 specified in the part drawing is as follows:

[0065]

[0066] The Almen test piece meets the requirements of the C-type test piece in the aviation standard HB / Z26 "Shot Peening of Parts".

[0067] Example 2

[0068] A projectile-type ultrasonic impact strengthening device for an Almen test piece, wherein the length of a bottom plate 701 is 0.2 mm smaller than the length of the Almen test piece 9, and the length m of an upper opening plane 801 is 0.5 mm smaller than the width of the Almen test piece.

[0069] A method for using a projectile-type ultrasonic impact strengthening device for an Almen specimen, characterized in that:

[0070] (1) According to the requirements of the parts drawing, select a projectile with a diameter of d, d = 0.6 mm.

[0071] (3) The tool head at the upper end of the horn 1 is passed through the lower opening plane 802 of the projectile cavity groove 8, Δh = 0.5 mm.

[0072] (4) Place N number of pellets into the pellet cavity 8. Rotate the knob 307 to move the screw 306, the slider 305, the lower pressing plate 6, the support plate 5, the Almen test piece fixing fixture 7 and the Almen test piece 9 downward together, so that the lower surface of the Almen test piece 9 contacts the upper opening plane 801, and the gap between the two is 0.05 mm.

[0073] (5) Turn on the power supply, and the tool head drives the projectile to perform high-speed Brownian motion and hit the surface of the Almen test piece. When the time reaches 30 seconds, turn off the power supply.

[0074] A method for using a shot-type ultrasonic impact strengthening device for an Almen test piece, characterized in that the relationship between the shot peening intensity I and the shot diameter d, the number of shots N, the height difference Δh, the height difference h between the upper opening plane 801 and the lower opening plane 802, the width L of the upper opening plane 801, and the side length l of the lower opening plane 802 specified in the part drawing is as follows:

[0075]

[0076] The Almen test piece meets the requirements of the C-type test piece in the aviation standard HB / Z26 "Shot Peening of Parts".

Claims

1. A projectile-type ultrasonic impact strengthening device for Almen test pieces, characterized in that: The invention comprises a horn (1), a cavity base (2), an adjustable bracket (3), a body bracket (4), a support plate (5), a lower pressure plate (6), a test piece fixture (7), and a projectile cavity groove (8); wherein the cavity base (2) and the adjustable bracket (3) are fixed on the body bracket (4), the cavity base (2) is located in front of the adjustable bracket (3), and is positioned by positioning pins respectively; the lower pressure plate (6) is located on the upper part of the support plate (5), and the right end is placed in the middle groove of the support plate (5), and is positioned by the adjustable The left end of the bracket (3) is connected and fixed; the Almen test piece (9) is fixed in the test piece groove (703) of the test piece fixture (7); the projectile mold cavity groove (8) is fixed on the cavity base (2); the tool head at the upper end of the amplitude change rod (1) passes through the lower opening plane (802) of the projectile mold cavity groove (8); the lower surface of the Almen test piece (9) contacts the upper opening plane (801) of the projectile mold cavity groove (8); and the upper plane of the tool head at the upper end of the amplitude change rod (1) is parallel to the lower opening plane (802); The upper opening plane (801) of the projectile-shaped cavity groove (8) is a rectangle, the length m is 0.5-1.0 mm smaller than the width of the Almen test piece, and the width is L; the lower opening plane (802) of the projectile-shaped cavity groove (8) is a square, the side length is l, the transition section (803) between the upper opening plane (801) and the lower opening plane (802) is an inclined plane, the angle between the inclined plane and the normal direction of the upper opening plane (801) is α, the height difference between the upper opening plane (801) and the lower opening plane (802) is h, and the height difference between the two is Δh; when the projectile diameter is 0.6 mm≤d≤1 mm, then 0≤Δh≤0.5 mm; when the projectile diameter is 1 mm<d≤2 mm, then 0≤Δh≤1 mm; The relationship between the shot peening intensity I specified in the part drawing and the shot diameter d, the number of shots N, the height difference Δh, the height difference h between the upper opening plane (801) and the lower opening plane (802), the width L of the upper opening plane (801), and the side length l of the lower opening plane (802) is as follows:

2. The projectile-type ultrasonic impact strengthening device for Almen test pieces according to claim 1, characterized in that: The adjustable support (3) is composed of a vertical support plate (301), an inclined support plate (302), a guide rail (303), a top plate (304), a slider (305), a screw rod (306) and a knob (307); the vertical support plate (301) is fixed on the fuselage support (4); the lower end of the inclined support plate (302) is connected and fixed to the fuselage support (4), and the upper end is connected and fixed to the vertical support plate (301); two parallel guide rails (303) are fixedly installed on one side of the vertical support plate (301); the guide rails (303) are fixedly installed on the one side of the vertical support plate (301); 03) is provided with a top plate (304) connected and fixed to the vertical support plate (301); a slider (305) is located between two parallel guide rails (303) and can move up and down along the guide rails (303); a groove on the upper part of the slider (305) is connected to the lower part of the screw rod (306); the screw rod (306) is inserted into the threaded hole in the center of the top plate (304) and is connected to the knob (307); the screw rod (306) and the slider (305) can be moved up and down by rotating the knob (307).

3. The projectile-type ultrasonic impact strengthening device for Almen test pieces according to claim 1, characterized in that: The test piece fixture (7) is composed of a bottom plate (701), two end fixtures (702) and a test piece slot (703); the test piece slot (703) is located in the center of the bottom plate (701), and the two end fixtures (702) and the bottom plate (701) are fixedly connected to press and fix the Almen test piece (9).

4. The projectile-type ultrasonic impact strengthening device for Almen test pieces according to claim 3, characterized in that: The length of the test strip slot (703) is consistent with the length of the bottom plate (701), and the length, width and depth of the test strip slot (703) are respectively consistent with the length, width and thickness of the Almen test strip (9), and the length of the bottom plate (701) is 0.2 to 1.0 mm smaller than the length of the Almen test strip (9).

5. The projectile-type ultrasonic impact strengthening device for Almen test pieces according to claim 1, characterized in that: The material of the projectile-shaped cavity (8) is resin.

6. A method for using a pellet-type ultrasonic impact strengthening device for an Almen test piece according to any one of claims 1 to 5, characterized in that: (1) According to the requirements of the parts drawing, select a projectile with a diameter of d, 0.6mm≤d≤2mm; (2) placing the Almen test piece (9) in the test piece slot (703) of the test piece fixture (7), and connecting and fixing the two end fixtures (702) and the bottom plate (701) by screws, thereby pressing and fixing the Almen test piece (9); (3) The tool head at the upper end of the horn (1) is passed through the lower opening plane (802) of the projectile cavity groove (8). When the projectile diameter is 0.6 mm ≤ d ≤ 1 mm, 0 ≤ Δh ≤ 0.5 mm; when the projectile diameter is 1 mm < d ≤ 2 mm, 0 ≤ Δh ≤ 1 mm; (4) placing N number of pellets into the pellet-shaped cavity (8), rotating the knob (307) to move the screw (306), the slider (305), the lower pressure plate (6), the support plate (5), and the specimen fixture (7) on which the Almen specimen (9) is fixed downward together, so that the lower surface of the Almen specimen (9) contacts the upper opening plane (801), and the gap between the two does not exceed 0.1 mm; (5) Turn on the power supply, and the tool head drives the projectile to perform high-speed Brownian motion and hit the surface of the Almen test piece. When it reaches 10 to 60 seconds, turn off the power supply; (6) Push the lower pressing plate (6) to slide along the length direction of the middle groove, align the upper opening plane (801) with the unstrengthened area of ​​the Almen test piece, and repeat step (5); (7) When the entire surface of the Almen test piece (9) is struck by the projectile, the knob (307) is rotated to move the screw rod (306), the slider (305), the lower pressure plate (6), the support plate (5), and the test piece fixture (7) on which the Almen test piece (9) is fixed upward together, the screws are loosened, the Almen test piece is removed, and the arc height value of the Almen test piece (9) is measured using a digital micrometer.

7. The method for using the pellet-type ultrasonic impact strengthening device for Almen test pieces according to claim 6, characterized in that: The Almen test piece (9) meets the requirements of type A and type C test pieces in the aviation standard HB / Z26 "Shot Peening of Parts".

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