TWI669501B - Residual stress detecting device and detecting method thereof - Google Patents

Abstract

The invention provides a residual stress detecting device and a testing method thereof, which are applied to the detection and calculation of surface residual stress for a curved surface and a coated detecting member, and the structure comprises: a detecting member carrier for fixing the detecting member to make the detecting member The point to be detected is maintained at the highest point; the X-ray generating source fixes or irradiates the X-ray to the point to be detected along a path; the detecting element includes a moving mechanism that causes the detecting element to follow the incident direction with the X-ray a path extending in an orthogonal direction, such that the detecting element receives the intensity of the detected diffracted X-ray at a position of the diffracted X-ray; and a stress calculation module that obtains a strain value based on the intensity peak of the diffracted X-ray detected by the detecting element, The residual stress value of the test piece is calculated by a calculation formula.

Description

Residual stress detecting device and detecting method thereof

The present invention relates to a residual stress detecting device and a detecting method thereof; more specifically, it relates to a residual stress detecting device for a curved coating and a detecting method thereof.

With the rapid development of the processing industry, coating technology and mold industry, and the development of high value, high precision and functionality, the analysis of coating life has been paid more and more attention. Residual stress is one of the important indicators of life analysis. However, because the carrier is a multi-surface geometry, it is easy to cause measurement error and numerical distortion due to the shape.

In the detection of residual stress, it is divided into contact and non-destructive testing. The commonly used contact residual stress measurement is mainly blind hole method, but the thickness of the coating is micron, and the blind hole method is not applicable. Therefore, the residual stress measurement of the coating is gradually measured by non-destructive measurement, while the non-destructive residual stress measurement is dominated by the X-ray diffraction method, and the non-destructive measurement can be measured in any process and each stage of use. Convenient for comprehensive control. However, because of the non-contact measurement, the workpiece carrier, material properties, geometry, and residual stress calculation parameters all affect the measurement data.

Residual stress is an important basis for judging process quality and material service life. Due to the use of workpieces, non-destructive testing is the mainstay, with X-Ray diffraction as the mainstream. At present, the principle of residual stress measurement by X-Ray diffraction method is based on the influence of stress on the material lattice, and the residual stress calculation is performed by fitting method with different measurement parameters. Therefore, it is divided into two measurement methods: sin ² Ψ and cos α, sin ² Ψ measurement parameters include rotation angle (ψ), tilt angle (Ψ) and other variables, suitable for small test pieces and laboratory expensive equipment; cos α is a variable of the diffraction ring and the light source and the detector are all on the same side, so it is suitable for large-sized workpieces and on-site measurement, but the above methods have the following disadvantages: 1. The residual stress measurement is mainly in the form of plane, not Applicable to the surface; 2. The calculation mode adopts the linear fitting method, and the influence caused by the surface will cause the measurement data to be distorted.

The problem to be solved by the present invention is to propose a residual stress detecting device and a calculation formula, which can be applied to the residual stress detection of a curved surface coating to solve the problem that the existing detection technology cannot accurately quantify the residual stress value of the curved coating.

In order to solve the above problems, the present invention discloses a residual stress detecting device for detecting and calculating surface residual stress for a curved surface and a coated detecting member, the structure comprising: a detecting member carrier for fixing the detecting member Having a point to be detected on the detecting member at a highest point; an X-ray generating source fixed or illuminating the X-ray to the point to be detected along a path; a detecting element including a moving mechanism, the moving mechanism The detecting element moves along a path extending in a direction orthogonal to an incident direction of the X-ray, so that the detecting element receives the intensity of detecting the X-ray at a position of the diffracted X-ray; and a stress calculation module A strain value is obtained based on the intensity peak of the diffracted X-ray detected by the detecting element, and the residual stress of the detecting member is calculated by a calculation formula value.

A residual stress detecting method using the residual stress detecting device as described above, the method comprising: fixing the detecting member to the detecting member carrier, and adjusting a point to be detected to a highest point; irradiating the X-ray generating source Moving to the point to be detected; moving the detecting element in a path extending in a direction orthogonal to the incident direction of the X-ray, and receiving the intensity of the detected X-ray to obtain a strain value; and transmitting the stress calculation module to The strain value calculates the residual stress value of the point to be detected.

In the above embodiment, the calculus is:

In the above calculation formula, σ f is the residual stress of the coating, Ef is the Young's modulus of the coating, ε _XRD is the strain value obtained by the residual stress detecting device of the present invention, Es is the Young's modulus of the substrate, and hs is the substrate. The thickness, hf is the thickness of the coating, k is the curvature of the point to be detected and x is the depth position of the point to be detected.

In one embodiment, the detecting carrier further includes a rotating mechanism that causes the detecting carrier to rotate to change an incident direction in which the detecting member receives X-rays.

In an embodiment, the detecting carrier is provided with a detecting member fixing structure.

In the above embodiment, the detecting and fixing structure is a fixing groove and a locking structure, and the detecting member is locked in the fixing groove.

In the above embodiment, the detecting member fixing structure further includes a level adjusting structure.

In an embodiment, the horizontal height adjusting structure is an ejector shape, which is disposed at the bottom of the fixing groove, and adjusts the point to be detected to the highest point by ejecting the position at the end of the detecting member.

The main features of the present invention are as follows: 1. The present invention is applicable to the detection of residual stress values of curved coated parts; 2. The stress calculation module and the test piece carrier proposed by the present invention can also be integrated into X-rays used today. The instrument is generated without increasing the cost; 3. Adjusting the point to be detected to the highest point can reduce the detection error, reduce the surface influence factor, effectively grasp the geometric characteristics, and break the detection error caused by the shape of the surface to be detected.

The present invention will be further described in conjunction with the drawings and specific embodiments, so that those skilled in the art can understand the invention and practice.

1‧‧‧Residual stress detecting device

10‧‧‧Test pieces

100‧‧‧ substrate layer

101‧‧‧ coating layer

11‧‧‧X-ray generation source

110‧‧‧X-ray

12‧‧‧Detection components

120‧‧‧Diffraction X-ray

13‧‧‧Test piece carrier

130‧‧‧Detector fixed structure

1301‧‧‧fixed slot

1302‧‧‧Locking structure

1303‧‧‧Horizontal height adjustment structure

14‧‧‧stress calculation module

P‧‧‧ Path

h _s ‧‧‧Substrate thickness

h _f ‧‧‧coating thickness

T‧‧‧ point to be tested

Ε‧‧‧ strain value

S1‧‧‧Residual stress detection method

S11~S14‧‧‧Steps

1A is a schematic structural view of a residual stress detecting device according to the present invention; FIG. 1B is a schematic view showing a detecting method of a residual stress detecting device according to the present invention; FIG. 1C is a schematic structural view of a curved coating detecting member according to the present invention; FIG. 2B is a schematic view of a detecting member carrier according to another embodiment of the present invention; and FIG. 3 is a flow chart of a residual stress detecting method according to the present invention.

The invention discloses a residual stress detecting device 1 , as shown in FIG. 1A to FIG. 1C , which is applied to the detection and calculation of surface residual stress for a curved surface and coated detecting member 10 , and the structure thereof comprises: a detecting member carrier 13 . For Fixing the detecting member 10 such that a point T to be detected on the detecting member 10 is maintained at the highest point; an X-ray generating source 11 is fixed or irradiated along the path P with the X-ray 110 to the point T to be detected; 12, comprising a moving mechanism for moving the detecting element 12 along the path P in a direction orthogonal to an incident direction of the X-ray 110, in other words, the path P is simultaneously incident with the X-ray 110 and The emission direction of the diffracted X-rays 120 is orthogonal, such that the detecting element 12 receives the intensity of the diffracted X-ray 120 at the position of the diffracted X-ray 120; and a stress calculation module 14 based on the diffraction detected by the detecting element 12. The intensity peak of the X-ray 120 is obtained by a strain value ε, and the residual stress value of the detecting member 10 is calculated by a calculation formula.

As shown in FIG. 1B, the method for detecting residual stress by the residual stress detecting device according to the present invention includes the steps of: fixing the detecting member 10 to the detecting member carrier 13 and adjusting the point T to be detected to the highest point. The X-ray 110 generating source 11 is irradiated toward the point T to be detected; as shown in FIG. 1A, the detecting element 12 is moved along the path P so that the detecting element 12 can be oriented in a direction orthogonal to the incident direction of the X-ray 110. And receiving the intensity of the diffracted X-ray 120 to obtain a strain value ε; and calculating the residual stress value of the point T to be detected by the stress calculation module 14 as shown in FIG. 1A.

In the above embodiment, the calculation formula is:

Where σ _f is the residual stress of the coating, E _f is the Young's modulus of the coating, ε _XRD is the strain value obtained by the residual stress detecting device of the present invention, E _s is the Young's modulus of the substrate, and h _s is the thickness of the substrate, h _f is the coating thickness, k is the curvature of the point T to be detected, and x is the depth position of the point T to be detected.

In the embodiment of FIG. 1B, the detecting device 13 is provided with a detecting member fixing structure 130, and the detecting fixing structure 130 is a fixing groove 1301 and a locking structure 1302, and the detecting member 10 is locked to the fixing member. In the slot 1301.

In one embodiment, the detecting carrier 13 further includes a rotating mechanism that causes the detecting carrier 13 to rotate to change the incident direction of the detecting member 10 to receive the X-rays 110.

In an embodiment described above, the rotating mechanism can be a two-dimensional 360 degree rotation.

In an embodiment described above, the rotating mechanism can be a three-dimensional 360 degree rotation.

With the residual stress detecting device described above, when the X-ray 110 is irradiated on the to-be-detected point T of the detecting member 10, the detecting element 12 can receive the intensity of the diffracted X-ray 120 and obtain an intensity peak to obtain the to-be-detected. A strain value ε at point T.

As shown in FIG. 1C, the coated curved detecting member 10 can be divided into a substrate layer 100 and a plating layer 101 according to its structure, and each has a substrate thickness h _s and a coating thickness h _f . After the detection device and the detection method of the invention obtain the strain value ε of the point T to be detected, the calculation formula can be substituted: The residual stress value σ _f is calculated.

σ _f in the calculation formula is the residual stress of the coating, E _f is the Young's modulus of the coating, ε _XRD is the strain value obtained by the residual stress detecting device of the present invention, E _s is the Young's modulus of the substrate, and h _s is the basis. The thickness of the material, h _f is the thickness of the coating, k is the curvature, and x is the depth position of the point T to be detected.

2A and 2B, FIG. 2A and FIG. 2B are schematic views of different embodiments of the detecting member carrier 13 of the present invention.

As shown in FIG. 2A, the detecting member carrier 13 of the present invention is provided with a detecting member fixing structure 130. The detecting fixing structure 130 is a fixing groove 1301 and a locking structure 1302, and the detecting member 10 is locked. In the fixing groove 1301, the point T to be detected can be maintained at the highest point as shown in FIG. 1B, and the point T to be detected is maintained at the highest point to reduce the detection error, reduce the surface influence factor, and effectively grasp the geometric characteristics. Break through the detection error caused by the offset of the shape of the surface to be detected.

As shown in FIG. 2B, the detecting member carrier 13 of the present invention is provided with a detecting member fixing structure 130. The detecting fixing structure 130 is a fixing groove 1301, a locking structure 1302 and a level adjusting structure 1303. The height adjustment structure 1303 is in an ejector form, and is disposed at the bottom of the fixing slot 1301. The level adjustment structure 1303 adjusts the point T to be detected to the highest point by ejecting the position at the end of the detecting member 10, thereby reducing the detection error. Reduce the influence factor of the surface, effectively grasp the geometric characteristics, and break the detection error caused by the offset of the shape of the surface to be detected.

Continuing to refer to FIG. 3, FIG. 3 is a residual stress detecting method S1 applied by the residual stress detecting device 1 as described above, the steps of which include: Step S11: fixing the detecting member to the detecting member carrier, and to be detected Adjusting the point to the highest point; step S12: illuminating the X-ray generating source to the point to be detected; Step S13: moving the detecting component to enable the detecting component to receive and detect the intensity of the diffracted X-ray in a direction orthogonal to the incident direction of the X-ray to obtain a strain value; and Step S14: transmitting the stress calculating module The residual stress value of the point to be detected is calculated from the strain value.

In an embodiment, the detecting carrier is rotatably changed to receive the incident direction of the X-ray to detect the X-ray intensity diffracted by the point to be detected at different angles, thereby obtaining an accurate strain value of the point to be detected. .

The strain values obtained by the above method are brought into the following formula: The residual stress value σ _f is calculated.

σ _f in the calculation formula is the residual stress of the coating, E _f is the Young's modulus of the coating, ε _XRD is the strain value obtained by the residual stress detecting device of the present invention, E _s is the Young's modulus of the substrate, and h _s is the basis. The thickness of the material, h _f is the thickness of the coating, k is the curvature of the point to be detected and x is the depth position of the point to be detected.

The residual stress detecting device and the detecting method thereof according to the present invention have the following characteristics: 1. The present invention breaks through the problem that the residual stress detecting is only applicable to the planar detecting member, and can be applied to the residual stress value detection of the curved coated member; The stress calculation module and the detection component carrier proposed by the invention can also be integrated into the X-ray generation instrument used today, without increasing the cost; 3. Adjusting the point to be detected to the highest point can reduce the detection error and reduce The surface influence factor effectively grasps the geometric characteristics and breaks the detection error caused by the offset of the shape to be detected.

In summary, it is only stated that the present invention is used to solve the problem. The embodiments or examples of the technical means are not intended to limit the scope of the practice of the invention. That is, the equivalent changes and modifications made to the scope of the patent application of the present invention, or the scope of the patent application of the present invention, are covered by the scope of the invention.

Claims (9)

A residual stress detecting device is applied to the detection and calculation of surface residual stress for a curved surface and a coated detecting member, and the structure comprises: a detecting member carrier for fixing the detecting member to make a waiting for the detecting member The detection point is maintained at the highest point; an X-ray generating source fixed or illuminating the X-ray to the point to be detected along a path; a detecting element including a moving mechanism, the moving mechanism moving the detecting element along the path, so that The detecting element can receive the intensity of detecting a diffracted X-ray in a direction orthogonal to an incident direction of the X-ray; and a stress calculation module that obtains a strain based on a peak intensity of the D-ray detected by the detecting element The value is calculated and the residual stress value of the test piece is calculated by a formula. The residual stress detecting device according to claim 1, wherein the calculation formula is: Where σ _f is the residual stress of the coating, E _f is the Young's modulus of the coating, ε _XRD is the strain value obtained by the residual stress detecting device of the present invention, E _s is the Young's modulus of the substrate, and h _s is the thickness of the substrate, h _f is the coating thickness, k is the curvature and x is the depth position of the point to be detected. The residual stress detecting device according to claim 1, wherein The detecting carrier further includes a rotating mechanism that causes the detecting carrier to rotate to change an incident direction in which the detecting member receives X-rays. The residual stress detecting device according to claim 1, wherein the detecting carrier is provided with a detecting member fixing structure. The residual stress detecting device of claim 4, wherein the detecting fixing structure is a fixing groove and a locking structure, and the detecting member is locked in the fixing groove. The residual stress detecting device of claim 4 or 5, wherein the detecting member fixing structure further comprises a level adjusting structure. The residual stress detecting device according to claim 6, wherein the horizontal height adjusting structure is an ejector shape, disposed at the bottom of the fixing groove, and the position to be detected is adjusted to a position at the end of the detecting member The highest point. A method for detecting a residual stress of a curved surface coating, comprising the steps of: providing a surface to be inspected by a curved coating, and adjusting a point to be detected on the coating to a highest point; and applying an X-ray source to the point to be inspected Irradiating an X-ray; enabling a detecting element to face a direction orthogonal to an incident direction of the X-ray, and receiving a intensity of detecting a diffracted X-ray to obtain a strain value; and calculating the waiting value by the strain value and a calculation formula The residual stress value of the detection point. The method for detecting a residual stress according to claim 8 of the patent application, wherein the calculation formula is: Where σ _f is the residual stress of the coating, E _f is the Young's modulus of the coating, ε _XRD is the strain value obtained by the residual stress detecting device of the present invention, E _s is the Young's modulus of the substrate, and h _s is the thickness of the substrate, h _f is the coating thickness, k is the curvature and x is the depth position of the point to be detected.