A projectile-type ultrasonic impact strengthening device for turbine disc tenon groove 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 turbine disk tenon groove and its use method. It comprises an adjustable base (1), a fuselage bracket (2), an adjustable bracket (3), a projectile cavity groove (4), a cavity base (5), a horn (6), a transducer fixing clamp (7) and a transducer (8); the present invention sets the structure of the device of the present invention, firstly closes the semi-open tenon groove completely to form a cavity, then places a hard projectile in the cavity, and the projectile impacts the inner wall of the cavity at high speed under ultrasonic excitation, so that the inner wall surface undergoes elastic-plastic deformation, thereby achieving surface strengthening. The strengthening effect of the tenon tooth surface is uniform, which solves the problem of structural interference and improves the uniformity of the strengthening effect of the tenon tooth surface, which is not only beneficial to improving the anti-fatigue strengthening effect of the turbine disk tenon groove, but also beneficial to reducing the deformation of the tenon tooth, and realizing the coordinated control of the shape and property.

Description

Technical Field

[0001] The invention belongs to the part surface treatment technology and relates to a projectile type ultrasonic impact strengthening device for a turbine disc tenon groove and a use method thereof. Background Art

[0002] The turbine disk has a harsh service environment and is subjected to multiple loads such as the centrifugal load of the blades, its own cyclic load, and high-temperature corrosion of the gas. It is prone to low-cycle fatigue failure and has become one of the "life-limited parts" of aircraft engines, which has attracted great attention. Among them, the tenon groove is one of the main areas where fatigue crack failure occurs. The reason is that, on the one hand, the tenon tooth transition R angle of the tenon groove has a high structural stress concentration coefficient. Under the action of alternating loads, the actual stress level borne by the R angle area is much higher than the external load, and even exceeds the yield strength of the material, which is very easy to cause low-cycle fatigue failure; on the other hand, the tenon tooth surface has fine cuts and a small bottom fillet radius, which has a high stress concentration coefficient, resulting in a high local surface stress concentration. Under alternating loads, it is very easy to induce the initiation of fatigue cracks; thirdly, the tenon tooth force surface contacts the blade tenon. If it is not assembled properly, under the action of alternating loads, alternating thermal expansion and contraction, there will be micro-wear between the two, which is easy to cause micro-fatigue failure of the tooth surface.

[0003] At present, the commonly used strengthening method for mortise and tenon is shot peening, which uses compressed gas to drive the projectile to hit the surface of the part. However, the gap between the tenons of the mortise and tenon is small (less than 10mm), and the force-bearing surface of the tenon is blocked by the adjacent structure and is difficult to be hit by the projectile. Therefore, it is difficult for the middle part of the force-bearing surface of the tenon to reach the shot peening intensity specified in the drawing, resulting in uneven shot peening effect on the surface of the tenon. On the one hand, the anti-fatigue effect of shot peening cannot reach the expected effect, and on the other hand, it causes the tenon to deform beyond the tolerance, affecting assembly. Summary of the invention

[0004] The purpose of the present invention is to propose a projectile-type ultrasonic impact strengthening device for a turbine disc tenon groove and a method of using the same, in order to overcome the problem of poor projectile accessibility of the tenon teeth of the turbine disc tenon groove and to improve the uniformity of the strengthening effect of the tenon teeth.

[0005] The technical solution of the present invention is: a projectile-type ultrasonic impact strengthening device for a turbine disc tenon groove: comprising an adjustable base 1, a fuselage bracket 2, an adjustable bracket 3, a projectile-shaped cavity groove 4, a cavity base 5, a variable amplitude rod 6, a transducer fixing clamp 7 and a transducer 8; wherein, the fuselage bracket 2 is fixed on the adjustable base 1; the adjustable bracket 3 and the cavity base 5 are fixed on the fuselage bracket 2 by locating pins, and the cavity base 5 is in front of the adjustable bracket 3; the projectile-shaped cavity groove 4 is fixed on the cavity base 5 by locating pins; the transducer 8 is connected to the variable amplitude rod 6 by internal threads, and the transducer 8 is connected and fixed to the fuselage bracket 2 by the transducer fixing clamp 7; the projectile-shaped cavity groove 4 is located directly below the turbine disc 9, closing the side of the tenon groove directly below the turbine disc 9, and the tool head at the upper end of the variable amplitude rod 6 closes the bottom of the tenon groove directly below the turbine disc 9, thereby completely closing the tenon groove to form a projectile-shaped cavity.

[0006] The adjustable bracket 3 includes a bottom plate 301, an oblique support rod 302, a vertical support plate 303, a top plate 304, a guide rail 305, a slider 306, a positioning hole bracket 307, a positioning pin 308, a disk center hole spindle 309, a wheel disc rear clamping plate 310, a wheel disc front clamping plate 311, a threaded rod 312, and a knob 313; wherein the bottom plate 301 is fixed to the fuselage bracket 2 and positioned by the positioning pin; the vertical support plate 303 is located on the bottom plate 301 and is connected and fixed to the bottom plate 301 by the oblique support rod 302; two parallel guide rails 305 are fixedly installed on one side of the vertical support plate 303; a top plate 304 is provided above the guide rail 305, which is connected and fixed to the vertical support plate 303; the slider 306 is located between the two parallel guide rails The groove on the upper part of the slider 306 is connected to the lower part of the threaded rod 312, the threaded rod 312 is inserted into the threaded hole in the center of the top plate 304, and is connected to the knob 313. There is a through hole in the center of the side of the slider 306, the right end of the disk center hole spindle 309 is inserted into the through hole, and the left end of the disk center hole spindle 309 is first inserted into the center hole of the wheel disc rear clamping plate 310, then inserted into the disk center hole of the turbine disc 9, and finally inserted into the center hole of the wheel disc front clamping plate 311, clamping and fixing the turbine disc 9; the positioning hole bracket 307 is fixed on the cavity base 5, and there is a positioning hole in the center of the top of the positioning hole bracket 307, and the positioning pin 308 passes through the mortise and tenon of the turbine disc 9 and is inserted into the positioning hole of the positioning hole bracket 307.

[0007] The gap between the projectile-shaped cavity groove 4 and the side of the tenon groove directly below the turbine disk 9 is 0.05mm-0.5mm, and the gap between the tool head at the upper end of the variable amplitude rod 6 and the bottom of the tenon groove directly below the turbine disk 9 is 0.05mm-0.5mm.

[0008] The ultrasonic frequency generated by the transducer 8 is 20-25 KHz, the resonance frequency of the horn 6 is 18-21 KHz, and the amplitude amplification factor is 12-16.

[0009] The angle between the upper end surface of the tool head at the upper end of the horn 6 and the normal line of the horizontal plane does not exceed 5°.

[0010] The central axis of the horn 6 is perpendicular to the cavity base 5 .

[0011] A method for using a projectile-type ultrasonic impact strengthening device for a turbine disc tenon groove:

[0012] (1) Install the turbine disk 9 and the rear clamping plate 310 of the wheel disk on the left end of the main shaft 309 of the center hole of the wheel disk, and then insert screws into the center hole of the front clamping plate 311 of the wheel disk and the threaded hole at the left end of the main shaft 309 of the center hole of the wheel disk in sequence to clamp and fix the turbine disk 9;

[0013] (2) placing a pellet in the pellet-shaped cavity 4;

[0014] (3) Rotate the knob 313 to lower the turbine disc so that the bottom of the tenon groove directly below the turbine disc 9 is close to the cavity base 5;

[0015] (4) The positioning pin 308 is passed through the upper tenon groove of the turbine disk 9 and then inserted into the positioning hole of the positioning hole bracket 307 to achieve accurate positioning of the turbine disk 9;

[0016] (5) Turn on the power supply, and the horn 6 moves up and down at high speed under the drive of the ultrasonic wave, driving the projectile to hit the inner wall of the tenon groove;

[0017] (6) After strengthening is completed, turn off the power, pull out the positioning pin 308, rotate the knob 313 to raise the turbine disc, loosen the screws, and remove the wheel disc front clamping plate 311 and the turbine disc 9.

[0018] The projectiles are spherical in shape, with a quantity of 10 to 80 and a diameter of Φ1mm to Φ2mm.

[0019] The projectile is made of ceramic shot or cast steel shot with a hardness of HRC55~62.

[0020] The time of ultrasonic impact strengthening is 10 to 60 seconds.

[0021] The advantages of the present invention are:

[0022] (1) By setting the structure of the device of the present invention, the shortcomings of interference in the mortise and tenon structure and poor accessibility of the projectile are overcome, and the projectile is prompted to perform Brownian motion at high speed in the cavity, so that the inner wall surface of the mortise and tenon (including the tenon teeth) is indiscriminately impacted by the projectile, thereby obtaining a uniform strengthening effect at all parts of the mortise and tenon. The hard projectile in the cavity is excited by an ultrasonic source to move, and the semi-open mortise and tenon structure is first completely closed to form a cavity. Then, a hard projectile is placed in the cavity, and the projectile impacts the inner wall of the cavity at high speed under ultrasonic excitation, so that the inner wall surface undergoes elastic-plastic deformation, thereby achieving surface strengthening.

[0023] (2) This method consumes only a small amount of shot (10 to 80 shots), which is far less than traditional shot peening, resulting in lower processing costs, less dust, and less noise.

[0024] (3) 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.

[0025] (4) This method improves the uniformity of the strengthening effect on the tenon surface, which is not only beneficial to improving the anti-fatigue strengthening effect of the turbine disk tenon groove, but also beneficial to reducing the deformation of the tenon and realizing the coordinated control of shape and property. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the whole device

[0027] Figure 2 Turbine disc assembly diagram

[0028] Figure 3 Schematic diagram of the assembly of the closed projectile cavity

[0029] Figure 4 Schematic diagram of the cross section of the closed projectile cavity

[0030] Among them: 1-adjustable base, 2-fuselage bracket, 3-adjustable bracket, 4-projectile cavity groove, 5-cavity base, 6-amplitude rod, 7-transducer fixing clamp, 8-transducer, 301-bottom plate, 302-oblique support rod, 303-vertical support plate, 304-top plate, 305-guide rail, 306-slider, 307-positioning hole bracket, 308-positioning pin, 309-disk center hole spindle, 310-wheel disc rear splint, 311-wheel disc front splint, 312-threaded rod, 313-knob DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with the accompanying drawings:

[0032] like Figure 1As shown, a projectile-type ultrasonic impact strengthening device for the tenon groove of a turbine disc comprises an adjustable base 1, a fuselage bracket 2, an adjustable bracket 3, a projectile-shaped cavity groove 4, a cavity base 5, a horn 6, a transducer fixing clamp 7 and a transducer 8; wherein, the fuselage bracket 2 is located on the adjustable base 1 and fixed by bolt connection; the adjustable bracket 3 is located on the fuselage bracket 2, positioned by a locating pin, and fixed by bolt connection. The cavity base 5 is located above the fuselage bracket 2 and before the adjustable bracket 3, positioned by a locating pin, and connected and fixed with the fuselage bracket 2 by bolts. The projectile-shaped cavity groove 4 is located above the cavity base 5, positioned by a locating pin, and fixed by bolt connection. The transducer 8 is connected to the horn 6 by an internal thread to ensure coaxiality, and the transducer 8 is connected and fixed to the fuselage bracket 2 by a transducer fixing clamp 7 to ensure that the central axis of the horn 6 is perpendicular to the cavity base 5.

[0033] like Figure 2 As shown, the adjustable bracket 3 includes a bottom plate 301, an oblique support rod 302, a vertical support plate 303, a top plate 304, a guide rail 305, a slider 306, a positioning hole bracket 307, a positioning pin 308, a disk center hole spindle 309, a wheel disc rear clamping plate 310, a wheel disc front clamping plate 311, a threaded rod 312, and a knob 313. Among them, the bottom plate 301 is located on the fuselage bracket 3, is positioned by a positioning pin, and is fixed by bolt connection. The vertical support plate 303 is located on the bottom plate 301, and is connected and fixed to the bottom plate 301 by an oblique support rod 302. Two parallel guide rails 305 are installed on one side of the vertical support plate 303, which are connected and fixed by screws. There is a top plate 304 above the guide rail 305, which is connected and fixed to the vertical support plate 303 by screws. The slider 306 is located between two parallel guide rails 305 and can move up and down along the guide rails 305. The groove on the upper part of the slider 306 is connected to the lower part of the threaded rod 312. The threaded rod 312 is inserted into the threaded hole in the center of the top plate 304 and connected to the knob 313. The threaded rod 312 and the slider 306 can be moved up and down by rotating the knob 313. There is a through hole in the center of the side of the slider 306. The right end of the disk center hole spindle 309 is inserted into the through hole, and the two are interference fit. The left end of the disk center hole spindle 309 is first inserted into the center hole of the wheel disc rear clamping plate 310, then inserted into the disk center hole of the turbine disc 9, and finally inserted into the center hole of the wheel disc front clamping plate 311, all of which are clearance fit. The disk center hole spindle 309, the wheel disc rear clamping plate 310 and the wheel disc front clamping plate 311 are fixed by screw connection to clamp and fix the turbine disc 9. By rotating the knob 313, the turbine disc 9 moves up and down along with the slider 306 and the main shaft 309 of the disc center hole. The positioning hole bracket 307 is located on the cavity base 5 and fixed by screws. There is a positioning hole in the center of the top of the positioning hole bracket 307. The positioning pin 308 passes through the tenon groove of the turbine disc 9 and is inserted into the positioning hole of the positioning hole bracket 307 to achieve accurate positioning of the turbine disc 9.

[0034] like Figure 3 , Figure 4 As shown, the projectile-shaped cavity groove 4 is located directly below the turbine disk 9, closing the side of the tenon groove directly below the turbine disk 9, and the tool head at the upper end of the amplitude change rod 6 closes the bottom of the tenon groove directly below the turbine disk 9, thereby completely closing the tenon groove to form a projectile-shaped cavity.

[0035] The gap between the projectile-shaped cavity groove 4 and the side of the tenon groove directly below the turbine disk 9 is 0.05mm-0.5mm, and the gap between the tool head at the upper end of the variable amplitude rod 6 and the bottom of the tenon groove directly below the turbine disk 9 is 0.05mm-0.5mm.

[0036] The ultrasonic frequency generated by the transducer 8 is 20-25 KHz, the resonance frequency of the horn is 18-21 KHz, and the amplitude amplification factor is 12-16.

[0037] The angle between the upper end surface of the tool head at the upper end of the horn 6 and the normal line of the horizontal plane does not exceed 5°.

[0038] A method for using a projectile-type ultrasonic impact strengthening device for a turbine disc tenon groove, (1) successively installing the turbine disc 9 and the rear clamping plate 310 of the wheel disc on the left end of the main shaft 309 of the center hole of the disc, and then inserting screws into the center hole of the front clamping plate 311 of the wheel disc and the threaded hole at the left end of the main shaft 309 of the center hole of the disc in sequence to clamp and fix the turbine disc 9.

[0039] (2) Place a shot in the shot-shaped cavity 4.

[0040] (3) Rotate the knob 313 to lower the turbine disc so that the bottom of the tenon groove directly below the turbine disc 9 is close to the cavity base 5.

[0041] (4) The positioning pin 308 is passed through the upper tenon groove of the turbine disk 9 and then inserted into the positioning hole of the positioning hole bracket 307 to achieve accurate positioning of the turbine disk 9.

[0042] (5) Turn on the power supply, and the horn 6 moves up and down at high speed under the drive of ultrasonic waves, driving the projectile to hit the inner wall of the mortise and tenon groove.

[0043] (6) After strengthening is completed, turn off the power, pull out the positioning pin 308, rotate the knob 313 to raise the turbine disc, loosen the screws, and remove the wheel disc front clamping plate 311 and the turbine disc 9.

[0044] The projectiles are spherical in shape, with a quantity of 10 to 80, a diameter of Φ1mm to Φ2mm, and are made of ceramic or cast steel shots with a hardness of HRC55 to 62.

[0045] The time of ultrasonic impact strengthening is 10 to 60 seconds.

[0046] The working principle of the present invention is:

[0047] 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, by setting the structure of the device of the present invention, the ultrasonic source is used to excite the movement of the hard projectile in the cavity, and the semi-open mortise and tenon of the structure are first closed to form a cavity, and then a hard projectile is placed in the cavity. The projectile hits the inner wall of the cavity at high speed under ultrasonic excitation, so that the inner wall surface undergoes elastic-plastic deformation and surface strengthening is achieved. Since the projectile performs Brownian motion in the cavity, the number of times and intensity of each part of the inner wall of the mortise and tenon (including the tenon tooth force surface) hit by the projectile is the same, so the strengthening effect of the tenon tooth surface is uniform, thereby solving the problem of structural interference and improving the uniformity of the strengthening effect of the tenon tooth surface, which is not only beneficial to improving the anti-fatigue strengthening effect of the turbine disk mortise and tenon, but also beneficial to reducing the deformation of the tenon and tenon, and realizing the coordinated control of the shape.

[0048] Embodiment 1:

[0049] The ultrasonic frequency generated by the transducer 8 is 20KHz, the resonance frequency of the horn is 18KHz, and the amplitude amplification factor is 12. Put the projectile in the projectile cavity 4. The projectile is spherical in shape, the number is 10, the diameter is Φ2mm, the material is cast steel shot, and the hardness is HRC55-62.

[0050] Example 2

[0051] The ultrasonic frequency generated by the transducer 8 is 25KHz, the resonance frequency of the horn is 21KHz, and the amplitude amplification factor is 16. The projectiles are spherical in shape, the number is 80, the diameter is Φ1mm, and the material is ceramic pellets.

[0052] After adopting the above method, the shot coverage rate of the tenon stress-bearing surface and the non-stress-bearing surface of the mortise is uniform, the surface roughness is basically the same, the surface residual compressive stress value is basically equivalent, and the depth difference of the hardened layer is no more than 20μm.

Claims

1. A projectile-type ultrasonic impact strengthening device for turbine disc tenon groove, characterized in that: The invention comprises an adjustable base (1), a body support (2), an adjustable support (3), a projectile cavity groove (4), a cavity base (5), a horn (6), a transducer fixing clamp (7) and a transducer (8); wherein the body support (2) is fixed on the adjustable base (1); the adjustable support (3) and the cavity base (5) are fixed on the body support (2) by means of positioning pins, and the cavity base (5) is located in front of the adjustable support (3); the projectile cavity groove (4) is fixed on the cavity base (5) by means of positioning pins; the transducer (8) is connected to the horn (6) by means of internal threads, and the transducer (8) is connected to the body support by means of the transducer fixing clamp (7). (2) connected and fixed; the projectile-shaped cavity groove (4) is located directly below the turbine disk (9), and the side of the tenon groove directly below the turbine disk (9) is closed; the tool head at the upper end of the amplitude change rod (6) closes the bottom of the tenon groove directly below the turbine disk (9), thereby completely closing the tenon groove to form a projectile-shaped cavity, the ultrasonic frequency generated by the transducer (8) is 20 to 25 kHz, the resonance frequency of the amplitude change rod (6) is 18 to 21 kHz, and the amplitude amplification factor is 12 to 16; the upper end face of the tool head at the upper end of the amplitude change rod (6) and the normal of the horizontal plane do not exceed 5°, and the central axis of the amplitude change rod (6) is perpendicular to the cavity base (5).

2. The projectile-type ultrasonic impact strengthening device for turbine disc tenon groove according to claim 1, characterized in that: The adjustable bracket (3) comprises a bottom plate (301), an oblique support rod (302), a vertical support plate (303), a top plate (304), a guide rail (305), a slider (306), a positioning hole bracket (307), a positioning pin (308), a disk center hole spindle (309), a wheel disc rear clamping plate (310), a wheel disc front clamping plate (311), a threaded rod (312), and a knob (313); wherein the bottom plate (301) is fixed on the fuselage bracket (2) and positioned by the positioning pin; the vertical support plate (303) is located on the bottom plate (301) and is connected and fixed to the bottom plate (301) by the oblique support rod (302); two parallel guide rails (305) are fixedly installed on one side of the vertical support plate (303); a top plate (304) is provided above the guide rail (305) and is connected and fixed to the vertical support plate (303); the slider (306) is located Between the two parallel guide rails (305), the groove on the upper part of the slider (306) is connected to the lower part of the threaded rod (312), the threaded rod (312) is inserted into the threaded hole in the center of the top plate (304), and is connected to the knob (313), there is a through hole in the center of the side of the slider (306), the right end of the disk center hole spindle (309) is inserted into the through hole, the left end of the disk center hole spindle (309) is first inserted into the center hole of the wheel disc rear clamping plate (310), then inserted into the disk center hole of the turbine disc (9), and finally inserted into the center hole of the wheel disc front clamping plate (311), so as to clamp and fix the turbine disc (9); the positioning hole bracket (307) is fixed on the cavity base (5), the top center of the positioning hole bracket (307) is provided with a positioning hole, and the positioning pin (308) passes through the tongue and groove of the turbine disc (9) and is inserted into the positioning hole of the positioning hole bracket (307).

3. The projectile-type ultrasonic impact strengthening device for turbine disc tenon groove according to claim 1, characterized in that: The gap between the projectile-shaped cavity groove (4) and the side of the tenon groove directly below the turbine disk (9) is 0.05mm-0.5mm, and the gap between the tool head at the upper end of the variable amplitude rod (6) and the bottom of the tenon groove directly below the turbine disk (9) is 0.05mm-0.5mm.

4. A method for using a projectile-type ultrasonic impact strengthening device for a turbine disk tenon groove according to any one of claims 1 to 3, characterized in that: (1) The turbine disk (9) and the wheel disk rear clamping plate (310) are successively mounted on the left end of the disk center hole main shaft (309), and screws are then inserted into the center hole of the wheel disk front clamping plate (311) and the threaded hole at the left end of the disk center hole main shaft (309) in sequence to clamp and fix the turbine disk (9); (2) placing a pellet in the pellet-shaped cavity (4); (3) Rotate the knob (313) to lower the turbine disc so that the bottom of the tenon groove directly below the turbine disc (9) is close to the cavity base (5); (4) The positioning pin (308) is passed through the upper tenon groove of the turbine disk (9), and then inserted into the positioning hole of the positioning hole bracket (307) to achieve accurate positioning of the turbine disk (9); (5) Turn on the power supply, and the horn (6) performs a high-speed up-and-down reciprocating motion driven by the ultrasonic wave, driving the projectile to hit the inner wall of the tenon groove; (6) After strengthening is completed, turn off the power supply, pull out the positioning pin (308), rotate the knob (313) to raise the turbine disc, loosen the screws, and remove the wheel disc front clamping plate (311) and the turbine disc (9).

5. The method for using the projectile-type ultrasonic impact strengthening device for turbine disk tenon groove according to claim 4 is characterized in that: The projectiles are spherical in shape, with a quantity of 10 to 80 and a diameter of Φ1mm to Φ2mm.

6. The method for using the projectile-type ultrasonic impact strengthening device for turbine disk tenon groove according to claim 4 is characterized in that: The projectile is made of ceramic shot or cast steel shot with a hardness of HRC55~62.

7. The method for using the projectile-type ultrasonic impact strengthening device for turbine disk tenon groove according to claim 4 is characterized in that: The time of ultrasonic impact strengthening is 10 to 60 seconds.

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