Cutting method and application suitable for high-temperature alloy disc contour method residual stress test

Abstract

The present application relates to residual stress detection technical field, especially to a kind of cutting method and application suitable for high-temperature alloy disc piece profile method residual stress test.The cutting method suitable for high-temperature alloy disc piece profile method residual stress test includes the following steps: (a) determining the position of profile cutting;(b) on the disc piece assembly supplementary block, so that the cutting surface of the disc piece in the cutting path direction The thickness remains consistent;(c) rigid hold is set on the two sides close to the cutting surface of the disc piece;(d) according to the determined cutting position, cutting is carried out using wire cutting technology.The cutting method of the present application, on the disc piece assembly supplementary block matched with the disc piece, so that the thickness of the disc piece on the cutting path always remains consistent, and the cutting section thickness does not mutate during cutting, ensuring accuracy.

Description

Technical Field

[0001] This invention relates to the field of residual stress detection technology, and in particular to a cutting method and its application suitable for residual stress testing of high-temperature alloy discs using the contour method. Background Technology

[0002] Residual stress is the stress that exists in equilibrium within an object even without external force, primarily originating from uneven plastic deformation during the manufacturing process. High-temperature alloys have low stacking fault energy and are difficult to recover from, therefore, compared to other metallic materials, residual stress is more prone to accumulation, difficult to release, and challenging to control, leading to various problems in subsequent processing and service.

[0003] Among existing methods for testing residual stress, X-ray diffraction can only measure residual stress in the surface plane; high-energy rays such as neutron diffraction have a certain testing depth but are costly and resource-constrained; drilling methods have limited resolution and cannot measure continuous distribution patterns; ultrasonic methods are immature and greatly affected by microstructure; and methods such as crack compliance and kerf analysis have limitations for the shape of disc or ring forgings. Research has found that the contour method can determine the chordal residual stress distribution perpendicular to the cut surface in disc / ring forgings. This method can be combined with dissected parts in mass production, is engineering-feasible, and has reasonable accuracy.

[0004] The basic principle of the profile method for measuring residual stress is to utilize the relationship between stress release and deformation, combining the finite element method and stress release techniques to calculate the internal stress distribution on a specific cross-section. The component is cut in half along the plane where stress needs to be evaluated using wire electrical discharge machining (EDM). Stress release causes deformation of the cut surface. Assuming the deformation profile of the cut surface is caused by the elastic release of residual stress and that the cutting process does not generate additional stress, if an external force is applied to restore the deformed cut surface to its pre-cut planar state, the resulting stress state is equivalent to the original residual stress on that plane before cutting. Therefore, the original internal stress value can be obtained using the deformation profile on the cut surface.

[0005] However, there are engineering problems with using the contour method to determine residual stress, such as symmetry errors caused by unstable cutting, which affect the accuracy of the measurement. In addition, for high-temperature alloy discs, there are also the following difficulties: (1) the cross-sectional shape of the high-temperature alloy disc cut radially is complex and the thickness often has abrupt changes; (2) the melting point of high-temperature alloys is high, and the EDM cutting speed has a significant impact on the quality of the cut surface.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] One objective of this invention is to provide a cutting method suitable for residual stress testing of high-temperature alloy discs using the contour method, thereby solving the technical problem of poor testing accuracy caused by unstable cutting in the prior art.

[0008] Another objective of this invention is to provide a method for testing residual stress in high-temperature alloy discs using the profile method.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] A cutting method suitable for residual stress testing of high-temperature alloy discs using the contour method includes the following steps:

[0011] (a) Determine the location for contour cutting;

[0012] (b) Assemble supplementary blocks on the disc to ensure that the thickness of the cut surface of the disc remains consistent in the cutting path direction;

[0013] (c) Rigid reinforcement is provided on both sides of the cut surface near the disc;

[0014] (d) Use wire cutting technology to cut at the determined cutting position.

[0015] In a specific embodiment of the present invention, the chemical composition of the supplementary block is the same as that of the disk.

[0016] In a specific embodiment of the present invention, the assembly method of the supplementary block and the disk includes: a mechanical rigid connection or an adhesive connection. Furthermore, there is no interaction force between the supplementary block and the disk in the cutting direction.

[0017] In a specific embodiment of the present invention, when adhesive bonding is used, the bonding position does not overlap with the cutting path.

[0018] In a specific embodiment of the present invention, the supplementary block is assembled at the stepped position of the disc. Further, the step is formed by connecting the upper or lower surface of the disc's rim to the outer edge of the disc's hub.

[0019] In a specific embodiment of the present invention, the supplementary block includes a first supplementary block, a second supplementary block, a third supplementary block, and a fourth supplementary block; the first supplementary block is fitted onto the step formed by the connection between the upper surface of the wheel rim and the outer edge of the wheel hub; the second supplementary block is fitted onto the step formed by the connection between the lower surface of the wheel rim and the outer edge of the wheel hub, and is located below the first supplementary block; the third supplementary block is fitted onto the step formed by the connection between the upper surface of the wheel rim and the outer edge of the wheel hub, and is located on opposite sides of the disc body in the radial direction from the first supplementary block; the fourth supplementary block is fitted onto the step formed by the connection between the lower surface of the wheel rim and the outer edge of the wheel hub, and is located below the third supplementary block. This arrangement ensures that the thickness of the disc is consistent along the cutting path, and that the height of the disc is the same as that of the central wheel hub throughout its radial range.

[0020] In a specific embodiment of the present invention, in step (d), the diameter of the cutting wire used for cutting satisfies:

[0021] When the maximum thickness of the disc is less than 15mm, the diameter of the cutting wire is 100-200μm;

[0022] When the maximum thickness of the disc is 15-50mm, the diameter of the cutting wire is 150-300μm;

[0023] When the maximum thickness of the disc is greater than 50 mm, the diameter of the cutting wire is 200-500 μm.

[0024] In a specific embodiment of the present invention, in step (d), the cutting speed is 0.1 to 5 mm / min.

[0025] In a specific embodiment of the present invention, the method further includes: after the cutting, removing the cut disc; performing contour scanning, contour regression and stress reconstruction on the cut surface, and calculating the value of the chordal residual stress of the disc.

[0026] The present invention also provides a method for testing residual stress of high-temperature alloy discs using the contour method, including any of the above-described cutting methods applicable to the residual stress testing of high-temperature alloy discs using the contour method.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] (1) The cutting method of the present invention assembles a supplementary block that matches the disc on the disc, so that the thickness of the disc on the cutting path remains consistent and the thickness of the cutting section does not change suddenly during the cutting process, thus ensuring accuracy.

[0029] (2) The cutting method of the present invention selects an appropriate cutting wire diameter according to the thickness of the disc and adopts an appropriate cutting speed to ensure appropriate cutting time and surface quality of the cut surface, thereby further improving the accuracy of measurement. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 A schematic diagram of the assembly structure of the disk and the supplementary block provided in an embodiment of the present invention;

[0032] Figure 2 A side view of the assembly structure of the disk and the supplementary block provided in an embodiment of the present invention;

[0033] Figure 3 This is a deformation contour diagram of the cut surface obtained by the cutting method in Embodiment 1 of the present invention;

[0034] Figure 4 This is a contour view of the cut surfaces on both sides obtained by the cutting method of Embodiment 2 of the present invention;

[0035] Figure 5 The deformed profile of the cut surface obtained by the cutting method in Comparative Example 1 is shown.

[0036] Figure 6 The chordal residual stress cloud diagram is obtained by calculating the cutting surface of the cutting surface obtained by the cutting method in Embodiment 1 of the present invention.

[0037] Figure 7 The diagram shows the chordal residual stress data calculated from the cutting surface obtained by the cutting method in Embodiment 1 of the present invention.

[0038] Figure 8 The chordal residual stress contour plot is calculated for the cutting surface obtained by the cutting method in Comparative Example 1.

[0039] Figure 9 The diagram shows the chordal residual stress data calculated from the cut surface obtained by the cutting method in Comparative Example 1. Detailed Implementation

[0040] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0041] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] A cutting method suitable for residual stress testing of high-temperature alloy discs using the contour method includes the following steps:

[0044] (a) Determine the location for contour cutting;

[0045] (b) Assemble supplementary blocks on the disc to ensure that the thickness of the cut surface of the disc remains consistent in the cutting path direction;

[0046] (c) Rigid reinforcement is provided on both sides of the cut surface near the disc;

[0047] (d) Use wire cutting technology to cut at the determined cutting position.

[0048] In the contour method for measuring residual stress, existing cutting methods suffer from symmetrical errors caused by cutting instability, affecting the accuracy of the measurement. Specifically, when the thickness of the cut section changes abruptly, the discharge current also changes abruptly, resulting in contour distortion at the abrupt change location, creating a "step" or irregular local cutting phenomenon, thus producing symmetrical errors.

[0049] The cutting method of the present invention assembles a supplementary block that matches the disc on the disc, so that the thickness of the disc on the cutting path remains consistent. During the cutting process, the thickness of the cutting section will not change abruptly, thus avoiding the change in discharge current caused by the change in cutting thickness, which in turn causes the abrupt change position to produce a symmetry error due to contour distortion.

[0050] In step (a), for the disc, the cutting position should be along the longitudinal direction of the diameter to cut the disc into two halves. Then, after cutting, the distribution characteristics of the chordal residual stress in the longitudinal section are measured.

[0051] In a specific embodiment of the present invention, the chemical composition of the supplementary block is the same as that of the disk.

[0052] In a specific embodiment of the present invention, the assembly method of the supplementary block and the disk includes: a mechanical rigid connection or an adhesive connection. Furthermore, there is no interaction force between the supplementary block and the disk in the cutting direction.

[0053] In a specific embodiment of the present invention, when adhesive bonding is used, the bonding location does not overlap with the cutting path, thus avoiding affecting the surface quality of the cut surface.

[0054] In a specific embodiment of the present invention, the supplementary block is assembled at the stepped position of the disc. Further, the step is formed by connecting the upper or lower surface of the disc's rim to the outer edge of the disc's hub.

[0055] In a specific embodiment of the present invention, the supplementary block includes a first supplementary block, a second supplementary block, a third supplementary block, and a fourth supplementary block; the first supplementary block is fitted onto the step formed by the connection between the upper surface of the wheel rim and the outer edge of the wheel hub; the second supplementary block is fitted onto the step formed by the connection between the lower surface of the wheel rim and the outer edge of the wheel hub, and is located below the first supplementary block; the third supplementary block is fitted onto the step formed by the connection between the upper surface of the wheel rim and the outer edge of the wheel hub, and is located on opposite sides of the disc body in the radial direction from the first supplementary block; the fourth supplementary block is fitted onto the step formed by the connection between the lower surface of the wheel rim and the outer edge of the wheel hub, and is located below the third supplementary block. This arrangement ensures that the thickness of the disc is consistent along the cutting path, and that the height of the disc is the same as that of the central wheel hub throughout its radial range.

[0056] In practice, a matching supplementary block is designed according to the size and shape of the high-temperature alloy disc to be tested, so that when the disc is cut along the cutting path after assembly, the thickness of the cross section (cut surface) to be tested remains consistent in the cutting direction.

[0057] In step (c), a rigid clamping method is used to prevent the disc from shifting or rotating during the cutting process. The rigid clamping and constraint are located on both sides of the cutting surface, and the rigid clamping constraint does not introduce stress into the disc in the normal direction of the cutting surface. In actual operation, the rigid clamping can be achieved by bolt fixing.

[0058] Figure 1 A schematic diagram of the assembly structure of the disk and the supplementary block provided in an embodiment of the present invention; Figure 2 This is a side view of the assembly structure of the disk and supplementary blocks provided in an embodiment of the present invention. As can be seen from the figure, each supplementary block is assembled with the disk as shown, so that the thickness of the cut surface of the disk remains consistent in the cutting path direction.

[0059] In a specific embodiment of the present invention, in step (d), the diameter of the cutting wire used for cutting satisfies:

[0060] When the maximum thickness of the disc is less than 15mm, the diameter of the cutting wire is 100-200μm;

[0061] When the maximum thickness of the disc is 15-50mm, the diameter of the cutting wire is 150-300μm;

[0062] When the maximum thickness of the disc is greater than 50 mm, the diameter of the cutting wire is 200-500 μm.

[0063] Selecting the cutting wire diameter according to the above requirements can reduce the impact of the cutting width on the measurement results during the cutting process, while avoiding problems such as prolonged cutting time or cutting wire breakage caused by an excessively small cutting diameter.

[0064] In different embodiments, when the maximum thickness of the disc is <15mm, the diameter of the cutting wire can be, for example, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, etc.; when the maximum thickness of the disc is 15-50mm, the diameter of the cutting wire can be, for example, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, etc. The diameters of the cutting wires can be, for example, 200μm, 210μm, 220μm, 230μm, 240μm, 250μm, 260μm, 270μm, 280μm, 290μm, 300μm, etc.; when the maximum thickness of the disc is >50mm, the diameter of the cutting wire can be, for example, 200μm, 220μm, 250μm, 280μm, 300μm, 320μm, 350μm, 380μm, 400μm, 420μm, 450μm, 480μm, 500μm, etc.

[0065] In a specific embodiment of the present invention, the cutting method is a unidirectional cutting method.

[0066] In a specific embodiment of the present invention, in step (d), the cutting speed is 0.1 to 5 mm / min, preferably 0.5 to 2 mm / min.

[0067] The above cutting speed is used to ensure the surface quality of the cut surface, with a surface roughness ≤1.6μm. When the cutting speed is >5mm / min, the surface quality is poor; while when the cutting speed is <0.1mm / min, the cutting time is too long, posing a risk of wire breakage.

[0068] In different implementations, the cutting speed in step (d) can be exemplarily 0.1 mm / min, 0.5 mm / min, 1 mm / min, 1.5 mm / min, 2 mm / min, 2.5 mm / min, 3 mm / min, 3.5 mm / min, 4 mm / min, 4.5 mm / min, 5 mm / min, etc.

[0069] In a specific embodiment of the present invention, the method further includes: after the cutting, removing the cut disc; performing contour scanning, contour regression and stress reconstruction on the cut surface, and calculating the value of the chordal residual stress of the disc.

[0070] After the disc is removed, the cut surface becomes an uneven curved surface due to the release of chordal residual stress. Then, contour scanning, contour regression and stress reconstruction are performed to calculate the value of the chordal residual stress of the disc.

[0071] The present invention also provides a method for testing residual stress of high-temperature alloy discs using the contour method, including any of the above-described cutting methods applicable to the residual stress testing of high-temperature alloy discs using the contour method.

[0072] Example 1

[0073] This embodiment provides a cutting method suitable for residual stress testing of high-temperature alloy discs using the contour method, including the following steps:

[0074] (1) Determine the location of the contour method cut: For the disc, the disc should be cut into two halves along the longitudinal direction of the diameter, and the distribution characteristics of the chordal residual stress in the longitudinal section should be determined.

[0075] (2) Based on the size and shape of the high-temperature alloy disc to be tested, according to... Figure 1 and Figure 2 The structure shown includes a supplementary block designed to match the disc, ensuring that the thickness of the cut surface of the disc remains consistent along the cutting path direction; the chemical composition of the supplementary block is consistent with that of the high-temperature alloy disc to be tested.

[0076] (3) Then, the supplementary block and the disk are connected by mechanical rigid connection or adhesive bonding. Figure 1 and Figure 2 Assembly can be carried out in a manner that, for example, uses adhesive to fix the supplementary block to the disc, and the adhesive position does not overlap with the cutting path.

[0077] (4) Rigid reinforcement is provided on both sides of the cutting surface near the disc to prevent displacement or rotation of the disc during cutting; the fixing and constraint positions are close to both sides of the cutting surface, such as... Figure 1 As shown. The clamping constraint will not introduce stress in the direction of the cut surface normal to the disc.

[0078] (5) Use wire cutting technology to cut at the determined cutting position; the maximum thickness of the disc is 150mm, the diameter of the cutting wire is 200μm, and the disc is cut into two halves in a slow unidirectional cutting method with a cutting speed of 1mm / min.

[0079] (6) After cutting, remove the cut disc; perform contour scanning, contour regression and stress reconstruction on the cut surface, and calculate the value of the residual stress in the chord direction of the disc.

[0080] Example 2

[0081] This embodiment provides a cutting method suitable for residual stress testing of high-temperature alloy discs using the contour method. Refer to Embodiment 1, except that step (4) is not included.

[0082] Example 3

[0083] This embodiment provides a cutting method suitable for residual stress testing of high-temperature alloy discs using the contour method. Referring to Embodiment 1, the only difference is that in step (5), the cutting speed is 10 mm / min.

[0084] Comparative Example 1

[0085] Comparative Example 1 refers to the cutting method of Example 1, except that steps (2) and (3) are not included.

[0086] Experimental Example 1

[0087] Figure 3 This is a deformation contour diagram of the cut surface obtained by the cutting method in Embodiment 1 of the present invention. Figure 4 This is a contour diagram of the cut surface obtained by the cutting method in Embodiment 2 of the present invention. From... Figure 3 As can be seen from the diagram, in the deformation contour map of the cut surface obtained using the cutting method of Example 1, no ripples appear at points A and B (Note: the ripples in the diagram are water stains left after cleaning). From Figure 4 As can be seen, without rigid support, the deformation profiles on the left and right sides of the disc are inconsistent. On the right side of the wire-cut disc, the deformation range of the cut surface is ±1mm; on the left side, the deformation range of the cut surface is ±0.5mm.

[0088] As can be seen from the radial deformation curve of the cut surface obtained by the cutting method of Embodiment 3 of the present invention, when the cutting is too fast, the surface quality of the cut surface is poor and there are periodic fluctuations.

[0089] Figure 5 The figure shows the deformation profile of the cut surface obtained by the cutting method of Comparative Example 1. As can be seen from the figure, in the deformation profile of the cut surface obtained by the cutting method of Comparative Example 1, there are fluctuations at points A and B due to the inconsistent cutting thickness.

[0090] Experiment Example 2

[0091] The cut surfaces obtained by the cutting methods of Example 1 and Comparative Example 1 were subjected to contour scanning, contour regression, and stress reconstruction to calculate the numerical value of the chordal residual stress of the disc. Specifically, Figure 6 and Figure 7 The images are, respectively, the chordal residual stress cloud diagram and the chordal residual stress data diagram obtained by calculating the cutting surface obtained by the cutting method of Embodiment 1 of the present invention; Figure 8 and Figure 9 The figures show the chordal residual stress cloud diagram and chordal residual stress data diagram calculated from the cut surface obtained by the cutting method of Comparative Example 1, respectively. The comparison shows that the calculated residual stress of the cut surface obtained by the cutting method of this invention exhibits stronger regularity, is closer to the actual results, and more accurately reflects the actual residual stress of the disc.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cutting method suitable for residual stress testing of high-temperature alloy discs using the contour method, characterized in that, Includes the following steps: (a) Determine the location for contour cutting; (b) Assemble supplementary blocks on the disc to ensure that the thickness of the cut surface of the disc remains consistent in the cutting path direction; (c) Rigid reinforcement is provided on both sides of the cut surface near the disc; (d) Cutting is performed using wire cutting technology at the determined cutting positions; The supplementary block includes a first supplementary block, a second supplementary block, a third supplementary block, and a fourth supplementary block; The first supplementary block is fitted onto the step formed by the connection between the upper surface of the wheel rim and the outer edge of the wheel hub; the second supplementary block is fitted onto the step formed by the connection between the lower surface of the wheel rim and the outer edge of the wheel hub, and is located below the first supplementary block; the third supplementary block is fitted onto the step formed by the connection between the upper surface of the wheel rim and the outer edge of the wheel hub, and is located on opposite sides of the disc in the radial direction from the first supplementary block; the fourth supplementary block is fitted onto the step formed by the connection between the lower surface of the wheel rim and the outer edge of the wheel hub, and is located below the third supplementary block.

2. The method according to claim 1, characterized in that, The chemical composition of the supplementary block is the same as that of the disk.

3. The method according to claim 1, characterized in that, The assembly method of the supplementary block and the disk includes: mechanical rigid connection or adhesive connection.

4. The method according to claim 3, characterized in that, There is no interaction force between the supplementary block and the disk in the cutting direction.

5. The method according to claim 1, characterized in that, The supplementary block is assembled at the stepped position of the disk component; The step is formed by connecting the upper or lower surface of the rim of the disc to the outer edge of the hub of the disc.

6. The method according to claim 1, characterized in that, In step (d), the diameter of the cutting wire used for cutting satisfies: When the maximum thickness of the disc is less than 15mm, the diameter of the cutting wire is 100~200μm; When the maximum thickness of the disc is 15~50mm, the diameter of the cutting wire is 150~300μm; When the maximum thickness of the disc is greater than 50 mm, the diameter of the cutting wire is 200~500 μm.

7. The method according to claim 1, characterized in that, In step (d), the cutting speed is 0.1~5 mm / min.

8. The method according to claim 7, characterized in that, The cutting speed is 0.5~2mm / min.

9. The method according to claim 7, characterized in that, The surface roughness of the cut surface is ≤1.6μm.

10. The method according to claim 1, characterized in that, Also includes: After the cutting, the cut disc is removed; The cut surface is subjected to contour scanning, contour regression, and stress reconstruction to calculate the numerical value of the chordal residual stress of the disc.

11. A method for testing residual stress in high-temperature alloy discs using the profile method, characterized in that, The cutting method described in any one of claims 1 to 10, applicable to residual stress testing of high-temperature alloy discs using the contour method, includes the cutting method described in any one of claims 1 to 10.

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