Method and apparatus for evaluating wire toughness

Abstract

The application provides a wire toughness evaluation method and device, and relates to the technical field of material analysis. The method comprises the following steps: when a target wire is symmetrically bent with a vertical line of a to-be-measured point tangential direction as a symmetric axis, the curvatures K of the to-be-measured point under different bending degrees are obtained; initial curvature K0, end curvature K2 and at least one transition curvature K1 between K0 and K2 are determined from the plurality of K, and K0 and K2 are measured before and after plastic deformation of the symmetric bending of the target wire respectively; the stress of the to-be-measured point of the target wire under K0, K1 and K2 is determined by adopting an X-ray diffraction method, and the stress at least includes a tangential stress; and the toughness characteristics of the target wire are determined according to at least one of the tangential stress of the to-be-measured point corresponding to K0, the tangential stress of the to-be-measured point corresponding to K1 and the tangential stress of the to-be-measured point corresponding to K2. The toughness characteristics of the wire can also be accurately characterized for the wire with a relatively thin diameter, so that the quality of the wire can be more comprehensively and accurately evaluated.

Description

Technical Field

[0001] The present application relates to the technical field of material analysis, and in particular to a method and device for evaluating the toughness of a wire. Background Art

[0002] Drawn wire has a wide range of applications. For example, steel wire, with its combination of high strength and good flexibility, is a key material in industries such as aviation, long-span bridges, and the nuclear industry. Tungsten wire is an important material for the production of filaments for various lighting fixtures, cathode ray tube filaments, vapor deposition heaters, thermocouples, electrodes and contact devices, and high-temperature heating elements. Quality control of wire is crucial. Existing industry and national standards such as JGJ19-2010 "Technical Specification for the Application of Cold-Drawn Low-Carbon Steel Wire" and GB / T5223-2002 "Steel Wire for Prestressed Concrete" specify testing methods such as surface quality, diameter deviation, tensile testing (tensile strength and elongation), and repeated bending testing. GB / T 4181-2017 "Tungsten Wire" specifies creep testing, high-temperature treatment, metallographic examination methods, and sag testing.

[0003] However, these testing methods still have shortcomings. First, they are not broad enough in scope. For example, the tensile strength test for steel wire is suitable for diameters of 3-12mm, while the bending test is suitable for diameters of 0.3mm-10mm. There is a lack of methods for accurately testing smaller wires, such as those with diameters <0.39±0.03mm. Second, the testing indicators are not comprehensive enough. For example, tungsten wire only specifies winding performance, tensile strength, and linearity, but lacks quantitative indicators for toughness.

[0004] Therefore, there is an urgent need for a wire toughness evaluation method that can accurately characterize the toughness characteristics of wires with smaller diameters, so as to more comprehensively and accurately evaluate the quality of the wires. Summary of the Invention

[0005] In order to achieve the above objectives, the present application provides a wire toughness evaluation method and device, which can accurately characterize the toughness characteristics of thinner diameter wires and more comprehensively and accurately evaluate the quality of the wires.

[0006] In a first aspect, the present application provides a method for evaluating the toughness of a wire material, the method comprising:

[0007] Select any point on the target wire as the test point;

[0008] When the target wire is symmetrically bent with the vertical line in the tangential direction of the test point as the symmetry axis, the curvature K of the test point under different bending degrees is obtained;

[0009] Determine an initial curvature K0, an end curvature K2, and at least one transition curvature K1 between the initial curvature and the end curvature from the plurality of curvatures K of the measured points, wherein the initial curvature K0 and the end curvature K2 are measured before and after the target wire material is symmetrically bent and plastically deformed, respectively;

[0010] Using X-ray diffraction, determine the stress of the target wire at the test point under the initial curvature K0, the transition curvature K1 and the terminal curvature K2, wherein the stress at least includes the tangential stress of the wire;

[0011] The toughness characteristic of the target wire material is determined according to at least one of the tangential stress at the test point corresponding to the initial curvature K0, the tangential stress at the test point corresponding to the transition curvature K1, and the tangential stress at the test point corresponding to the terminal curvature K2.

[0012] In one possible implementation, determining the initial curvature K0 from the curvatures K of the plurality of points to be measured includes:

[0013] If the wire segment of the target wire at the test point is not curled under no stress, the curvature K of the test point when the target wire is bent to the point where the tangential stress is greater than 0 is determined as the initial curvature K0;

[0014] If the wire segment where the to-be-measured point of the target wire is located curls under an unstressed state, the curvature K of the to-be-measured point under the unstressed state is determined as the initial curvature K0.

[0015] In one possible implementation, determining the initial curvature K0 from the curvatures K of the plurality of points to be measured includes:

[0016] The smallest curvature among the curvatures K of the plurality of points to be measured is determined as the initial curvature K0.

[0017] In one possible implementation, the stress determined by the X-ray diffraction method also includes radial stress, and determining the end curvature K2 from the curvatures K of the plurality of measured points includes:

[0018] During the symmetrical bending process, the curvature of the target wire at the point to be measured when the direction of the radial stress on the point to be measured changes is determined as the terminal curvature K2.

[0019] In one possible implementation, determining the toughness characteristic of the target wire material according to at least one of the tangential stress at the test point corresponding to the initial curvature K0, the tangential stress at the test point corresponding to the transition curvature K1, and the tangential stress at the test point corresponding to the terminal curvature K2 includes at least one of the following:

[0020] Determine the value of the tangential stress at the measuring point corresponding to the initial curvature as a first toughness factor, wherein the first toughness factor characterizes the initial deformation degree of the wire material;

[0021] arbitrarily selecting two tangential stress values ​​from the tangential stress at the measuring point corresponding to the initial curvature K0, the tangential stress at the measuring point corresponding to the transition curvature K1, and the tangential stress at the measuring point corresponding to the terminal curvature K2, and calculating the rate of change between the two tangential stress values ​​to obtain a second toughness factor, wherein the second toughness factor characterizes the stress resistance of the wire material;

[0022] The value of the tangential stress at the measuring point corresponding to the end curvature K2 is determined as the third toughness factor, and the third toughness factor characterizes the durability of the wire material;

[0023] Obtain the residual stress of the target wire at the test point after the target wire is placed for a target time when the curvature of the test point is not zero, and determine the value of the residual stress as the fourth toughness factor, which characterizes the deformation recovery ability of the wire.

[0024] In one possible implementation, after determining the toughness characteristics of a first wire and a second wire of the same material but different specifications, the method further includes:

[0025] The second toughness factors of the first wire material and the second wire material are compared to obtain a first evaluation result. In the first evaluation result, the larger the value of the second toughness factor is, the better the toughness of the corresponding specification is.

[0026] In one possible implementation, after determining the toughness characteristics of the third and fourth wires of the same material and specification, the method further includes:

[0027] Calculating the sum of the first toughness factor, the third toughness factor, and the fourth toughness factor for the third wire and the fourth wire respectively to obtain a toughness index of the third wire and a toughness index of the fourth wire;

[0028] The toughness index of the third wire material and the toughness index of the fourth wire material are compared to obtain a second evaluation result. In the second evaluation result, a wire material with a larger toughness index has relatively better toughness.

[0029] In one possible implementation, the target wire material is a tough material, and the tough material includes a metal material, and the metal material includes an alloy of one or more of tungsten, molybdenum, and steel.

[0030] In one possible implementation manner, the diameter φ of the target wire material meets the following conditions: 0.038±0.003 mm≤φ≤0.39±0.03 mm.

[0031] In a second aspect, a wire toughness evaluation device is provided, which includes a plurality of functional modules for performing corresponding steps in the wire toughness evaluation method provided in the first aspect.

[0032] In a third aspect, a computing device is provided, which includes a memory and a processor, the memory storing at least one program, and the at least one program being executed by the processor to implement the wire toughness evaluation method provided in the first aspect.

[0033] In a fourth aspect, a computer readable storage medium is provided, which stores at least one program, and the at least one program is executed by a processor to implement the wire toughness evaluation method provided in the first aspect.

[0034] In a fifth aspect, a computer program product is provided, which includes computer programs / instructions, and the computer programs / instructions are executed by a processor to implement the wire toughness evaluation method provided in the first aspect.

[0035] The technical solutions provided in the present application have at least the following technical effects:

[0036] A brand-new toughness evaluation method is provided for a wire with a relatively thin diameter, and the curvatures of the wire under different bending conditions are selected to represent different bending stages; the tangential stress causing toughness fracture is used as the main index for analysis, and the multi-dimensional toughness characteristics of the wire are accurately represented by analyzing the numerical values and changes of the tangential stress in different stages, so that the quality of the wire is more comprehensively and accurately evaluated. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a flowchart of a wire toughness evaluation method provided in an embodiment of the present application;

[0038] Figure 2 is a schematic diagram of a sample coordinate system of an XRD method provided in an embodiment of the present application;

[0039] Figure 3 is a flowchart of another wire toughness evaluation method provided in an embodiment of the present application;

[0040] Figure 4 is a schematic diagram of a wire toughness evaluation device provided in an embodiment of the present application;

[0041] Figure 5 is a hardware structure schematic diagram of a computing device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] To further illustrate each embodiment, the present application provides drawings. These drawings are part of the disclosure of the present application and are mainly used to illustrate the embodiments and to explain the operating principles of the embodiments in conjunction with the relevant descriptions in the specification. With reference to these contents, a person of ordinary skill in the art should be able to understand other possible implementations and the advantages of the present application. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components. The term "at least one" in the present application means one or more, and the term "plurality" in the present application means two or more.

[0043] The present application will now be further described with reference to the accompanying drawings and specific implementation methods.

[0044] The present application provides a wire toughness evaluation method suitable for fine-diameter drawn wire, which combines X-ray diffraction (XRD) stress testing to quickly characterize the toughness of the wire, and can provide a new toughness evaluation index to more accurately judge the quality of the wire. XRD stress testing is a method of measuring the internal stress of a material using X-ray diffraction technology. The stress applied to the wire during drawing and bending is analyzed by the XRD method, which can be decomposed along three directions, namely radial, axial and tangential (or circumferential), and the force is a three-dimensional stress state. Brittle fracture is caused by the axial stress (tensile stress component) of the applied stress, and ductile fracture is caused by the shear stress component. Therefore, the measured stress component can be used as an evaluation benchmark for the toughness of the wire. Based on this, the present application provides a variety of specific embodiments in combination with the accompanying drawings to illustrate the technical solution of the present application.

[0045] Example 1

[0046] The embodiments of the present application provide a method for evaluating the toughness of a wire material. Figure 1 This is a flow chart of a method for evaluating wire toughness provided in an embodiment of the present application. Figure 1 As shown, the method includes the following steps S1, S2, S3 and S4.

[0047] S1. Select any point on the target wire as the test point. When the target wire is symmetrically bent with the vertical line in the tangential direction of the test point as the symmetry axis, obtain the curvature K of the test point under different bending degrees.

[0048] In the embodiments of the present application, the target wire material refers to a tough material obtained by stretching, which generally has good stretchability and ductility.

[0049] Curvature refers to the curvature of the wire. The curvature of the wire varies depending on the magnitude of the external force applied to it. By maintaining the wire at different curvatures, the current external force applied to the wire can be quantified and identified. A greater curvature indicates a greater external force.

[0050] In the embodiments of the present application, the curvature of the wire is used to represent its bending degree, and the greater the bending degree, the greater the curvature. That is, as the bending degree changes from small to large, the curvature also changes from small to large.

[0051] In one possible implementation, the target wire material is made of a tough material, and the tough material includes a metal material, and the metal material includes an alloy of one or more of tungsten, molybdenum, and steel.

[0052] In one possible implementation, the thin diameter range targeted by the wire toughness evaluation method provided in the present application, that is, the diameter φ of the target wire to be evaluated complies with the range of: 0.038±0.003mm≤φ≤0.39±0.03mm.

[0053] The technical solution of the present application has significant accuracy and comprehensiveness in evaluating toughness in the above-mentioned narrow diameter range. Of course, the technical solution of the present application can also be used to evaluate wires of other diameters, and is not limited thereto.

[0054] By simplifying the toughness testing process to easily measurable curvature, the convenience of data measurement can be improved.

[0055] S2. Determine an initial curvature K0, an end curvature K2, and at least one transition curvature K1 between the initial curvature and the end curvature from the curvatures K of the multiple points to be measured.

[0056] The initial curvature K0 and terminal curvature K2 are measured before and after the target wire undergoes symmetrical bending and plastic deformation, respectively. The initial curvature K0 serves as the starting value for evaluating the target wire, characterizing its initial bending state when unstressed. The terminal curvature K2 serves as the final value for evaluating the target wire, characterizing its ultimate toughness when stressed.

[0057] In a possible implementation manner, the initial curvature K0 may be determined in different ways according to different natural states of the target wire material.

[0058] (1) Natural curling state: If the wire segment of the target wire at the test point is not curled under no stress, the curvature K of the test point when the target wire is bent to the point where the tangential stress is greater than 0 is determined as the initial curvature K0.

[0059] (2) Natural non-curling: If the target wire curls when the test point is not under stress, the curvature K of the test point in the unstressed state is determined as the initial curvature K0. This method combines the tangential stress calculated by the XRD stress test method to accurately find the state where stress is just beginning, avoiding the inclusion of a large number of curvatures corresponding to the unstressed state in the evaluation range, improving the accuracy of the evaluation, and saving testing time.

[0060] (3) Arbitrary state: The minimum of the multiple curvatures K measured is determined as the initial curvature. Considering that curvature is a representation of bend, the greater the bend, the greater the curvature. Therefore, the minimum curvature is directly used as the initial curvature K0 to represent the initial bending state of the target wire. This method can reduce the difficulty of testing, does not require the analysis of tangential stress, has low calculation difficulty, and is highly applicable.

[0061] It should be noted that the presence of curl in the natural state can be determined visually, for example, by observing whether the surface of the wire exhibits noticeable curl or wavy patterns. Simpler instruments or equipment can also be used to detect curl, such as a curl tester, which can visually or through projection methods observe the curl per unit length of the wire; a magnifying glass or microscope, which can be used to observe the surface or end face of the wire to check for curl; and a manual curl measurement tool, similar to a simple ruler or template, which can be set to a certain length and angle standard to manually measure the curl of the wire.

[0062] Among them, the plastic deformation of the wire refers to the permanent deformation that occurs when the wire is subjected to external force and exceeds its elastic limit, that is, the deformation cannot be restored to the original shape and size after the external force is removed, but the internal atomic structure of the material is not destroyed.

[0063] When a wire is deformed by an external force, the stress it is subjected to undergoes a series of changes. As the stress increases, the wire reaches a specific yield point, where the stress remains almost constant while the strain continues to increase, marking the transition of the material from elastic deformation to plastic deformation.

[0064] In one possible implementation, whether plastic deformation has been achieved can be determined by analyzing the change in radial stress of the target wire at the test point under the current curvature. For example, the change in radial stress of the target wire is analyzed to test whether plastic deformation has been achieved.

[0065] Theoretically, the greater the curvature of the wire, that is, the greater the applied external force, the greater the residual stress generated within the wire to maintain equilibrium. When plastic deformation has not occurred (yield limit has not been reached), the wire surface should theoretically be subject to tensile stress in the radial direction and compressive stress in the tangential direction. As the curvature (external force) increases, the tangential stress should also show a significant upward trend. When the external force increases to a critical value or greater, and the wire undergoes significant plastic deformation, the tangential stress decreases, and the radial stress decreases to the point where it switches from tensile stress to compressive stress. In other words, the direction of the radial stress changes.

[0066] Specifically, the stress determined by the XRD method also includes radial stress. During the symmetrical bending process, the curvature of the target wire at the test point when the direction of the radial stress on the test point changes is defined as the terminal curvature K2.

[0067] Therefore, the timing of plastic deformation can be judged by the radial stress, thereby accurately determining the terminal curvature K2.

[0068] The transition curvature K1 is measured between the initial curvature K0 and the final curvature K2. As the curvature increases from small to large, the measured curvature also increases. Therefore, the three curvatures are arranged in ascending order: initial curvature K0, transition curvature K11, transition curvature K12, ..., and final curvature K2.

[0069] S3. Using X-ray diffraction, determine the stress of the target wire at the test point under the initial curvature K0, transition curvature K1 and terminal curvature K2.

[0070] In the present application, in the embodiment, the measured stress includes at least the tangential stress suffered by the wire. The stress suffered during wire drawing and bending is analyzed by XRD method, which can be decomposed in three directions, namely radial, axial and tangential (or circumferential), and the force is a three-dimensional stress state. The toughness fracture of the wire is caused by the tangential stress component, so the measured stress component can be used as an evaluation benchmark for the toughness of the wire.

[0071] In one possible embodiment, the relationship between the sample coordinate system and the experimental coordinate system related to the XRD stress test is preset as follows: when the horizontal rotation angle φ of the laboratory coordinate system is 0°, the axial direction of the drawn wire is the same as the direction of the X-ray diffraction light path, and the stress measured by the tilt method at this time includes the radial stress and tangential stress of the wire.

[0072] In one possible implementation, the method for calculating the three-dimensional stress of a test point of a material based on the XRD method refers to the national standard "GB / T 7704-2017 Non-destructive Testing X-ray Stress Determination Method", which will not be described in detail here. Specifically, the axial (or tangential) stress σ of the wire is calculated φ and tangential stress τ φ Formula (30) and Formula (31) in GB / T 7704-2017 Nondestructive Testing X-ray Stress Determination Method can be used. Of course, other mathematical methods, fitting algorithms, or prediction methods can also be used to achieve the above-mentioned solution of three-dimensional stress, and this application does not limit them here.

[0073] Figure 2 This is a schematic diagram of an XRD sample coordinate system provided in an embodiment of the present application, such as Figure 2 As shown in the figure, O is a test point on the surface of the test sample (specimen), Ψ is the tilt angle of the tested sample relative to the surface normal of the sample coordinate system S1S2S3; OP is the normal direction of the crystal plane to be tested; S φ The stress direction of the plane stress is the plane stress (axial or radial) stress σ φ and tangential stress τ φWhen the horizontal rotation angle φ of the laboratory coordinate system is set to 0°, the sample coordinate system S of the target wire is φ The radial direction is the same as its own, so the stress on the S1OS2 plane of the sample coordinate system S1S2S3 measured at this time is the radial stress σ of the wire φ And, tangential stress τ φ Perpendicular to the S1OS2 plane.

[0074] S4. Determine the toughness characteristic of the target wire material according to at least one of the changes among the tangential stress at the test point corresponding to the initial curvature K0, the tangential stress at the test point corresponding to the transition curvature K1, and the tangential stress at the test point corresponding to the terminal curvature K2.

[0075] In the embodiments of the present application, the tangential stress corresponding to the initial curvature is used to characterize the initial bending state, the tangential stress corresponding to multiple transition curvatures is used to characterize the rate of change of tangential stress during the bending process, and the tangential stress corresponding to the terminal curvature characterizes the value of the tangential stress when bending to the tough end. Based on these aspects, the toughness characteristics of the wire can be comprehensively evaluated.

[0076] In one possible implementation, the determined toughness characteristic includes at least one of the first toughness factor, the second toughness factor, the third toughness factor, and the fourth toughness factor shown below.

[0077] (1) First toughness factor characterizing the initial deformation degree of the wire: The value of the initial curvature corresponding to the tangential stress is directly determined as the first toughness factor. For example, the absolute value of the initial curvature corresponding to the tangential stress can be taken to obtain the first toughness factor, as shown in formula (1).

[0078] R1=|τ0|(1)

[0079] In formula (1), R1 is the first toughness factor, and τ0 is the tangential stress corresponding to the initial curvature.

[0080] Specifically, initial curvature represents the natural state. If there is a natural bend in this state, the straightness is poor. In theory, poor straightness indicates more plastic deformation, which means poor toughness. Under the same curvature state, the shear stress of a wire with poor toughness should be lower. Therefore, a larger value of the first toughness factor indicates better toughness.

[0081] (2) The second toughness factor characterizing the stress resistance of the wire: for any two transition curvatures, the rate of change between the tangential stresses corresponding to each two transition curvatures is calculated to obtain the second toughness factor.

[0082] Specifically, for the transition curvatures K11 and K12, the rate of change of the shear stress between the two transition curvatures can be calculated by the following formula (2).

[0083] R2=(τ12 -τ 11 ) / τ 11 *100% (2)

[0084] In formula (2), R2 is the second toughness factor; τ 11 is the tangential stress corresponding to the transition curvature K11; τ 12 is the tangential stress corresponding to the transition curvature K12. R2 represents the rate of change. The larger the rate of change, the closer the external force on the wire is to the critical value (yield point) during the symmetrical bending stage.

[0085] In the embodiments of the present application, when the rate of stress change increases, if the grain structure within the wire cannot adjust in time, the wire may easily break. Therefore, by calculating the second toughness factor, the wire's ability to withstand rapid stress changes can be evaluated. Furthermore, the second toughness factor can also reflect the wire's ability to respond to external stress changes when subjected to external forces, that is, whether the wire can maintain its structural integrity and performance stability when subjected to rapid stress changes.

[0086] (3) The third toughness factor characterizing the durability of the wire material: The value of the tangential stress corresponding to the terminal curvature K2 is determined as the third toughness factor. For example, the third toughness factor can be obtained by taking the absolute value of the tangential stress corresponding to the terminal curvature K2, as shown in formula (3).

[0087] R3=|τ2|(3)

[0088] In formula (3), R3 is the third toughness factor, and τ2 is the tangential stress corresponding to the end curvature K2.

[0089] (4) A fourth toughness factor characterizing the deformation recovery ability of the wire material: Obtain the residual stress at the target wire material at the target point after the target wire material is placed for a target time while the curvature at the target point is not zero, and determine the value of the residual stress as the fourth toughness factor. Optionally, the target time is a given relaxation time.

[0090] In one possible embodiment, after a given relaxation time (target duration), the stress state within the material undergoes a process from instability to gradual stability. The residual stress after the target relaxation time refers to the relatively stable stress state achieved within the material after the target duration. For example, the fourth toughness factor can be the absolute value of the residual stress, as shown in formula (4).

[0091] R4=|τ H |(4)

[0092] In formula (4), R4 is the fourth toughness factor, τ H The residual stress at the test point is measured after maintaining a certain curvature (i.e. the curvature of the test point is not 0) for H hours.

[0093] In the embodiments of the present application, relaxation time describes the time required for a wire material to transition from one state to another. When subjected to external stress or impact, the residual stress after relaxation of the material can reflect its deformation recovery ability.

[0094] In one possible implementation, by calculating any one or more combinations of the above-mentioned various toughness factors, the toughness characteristics of the wire material can be obtained, thereby comprehensively analyzing the toughness of the wire material in multiple dimensions.

[0095] In one possible implementation, the target filaments include multiple groups of filaments. After the toughness characteristics of the target filaments are determined, the quality of the different groups of filaments can be analyzed by comparing the toughness factors of the multiple groups of filaments.

[0096] In one possible implementation, the multiple groups of wires are made of the same material but have different specifications. The comparative analysis process includes:

[0097] For a first wire material and a second wire material having the same material but different specifications, the second toughness factors of the first wire material and the second wire material are compared to obtain a first evaluation result.

[0098] Among them, in the first evaluation result: the larger the value of the second toughness factor, the better the toughness of the corresponding specification.

[0099] In another possible implementation, the multiple groups of wire materials are made of the same material and have the same specifications, and the comparative analysis process includes:

[0100] For a third wire and a fourth wire of the same material and specification, respectively, the sum of the first toughness factor, the third toughness factor, and the fourth toughness factor is calculated for the third wire and the fourth wire to obtain a toughness index of the third wire and a toughness index of the fourth wire;

[0101] The toughness index of the third wire material and the toughness index of the fourth wire material are compared to obtain a second evaluation result. In the second evaluation result, a wire material with a larger toughness index has relatively better toughness.

[0102] The above toughness index can be expressed as: R = |R1+R3+R4|, R1, R3 and R4 refer to formulas (1), (3) and (4), which will not be repeated here.

[0103] Example 2

[0104] The present invention provides another method for evaluating the toughness of a wire. Figure 3 This is a flow chart of another method for evaluating the toughness of a wire provided in an embodiment of the present application. Figure 3 The following describes a method for evaluating the toughness of a wire according to an embodiment of the present application.

[0105] In the embodiment of the present application, the target wire is symmetrically bent with the vertical line of the tangential direction of the point to be measured as the axis of symmetry, the endpoint of the short side of the target wire is parallel to the tangential direction of the point to be measured, and the straight line intersects with the target wire long side at point A, and the straight-line distance d (hereinafter referred to as silk foot straight-line distance d) between the short side endpoint and point A of the target wire is used to characterize the curvature. The shorter the straight-line distance between the two silk feet of the wire, the larger the curvature of the target wire is, and the larger the degree of curvature is. It is understandable that straight-line distance is easy to measure and can accurately indirectly characterize the curvature of the wire, and this measurement parameter can be used to improve the convenience of data measurement. Of course, in other embodiments, other measurement parameters, indicators can also be used to characterize the curvature, or directly use curvature measurement instrument to measure the curvature.

[0106] 201. Sample preparation.

[0107] For example, a 5-10 cm section of wire is cut, maintained at a certain curvature, and placed horizontally or vertically on a sample stage. The relationship between the sample coordinate system and the laboratory coordinate system is as follows: when the instrument sample stage's horizontal rotation angle φ is 0°, the axis of the drawn wire segment to be measured is parallel to the diffraction beam path, and the point to be measured lies on this segment.

[0108] 202. Test preparation.

[0109] The test preparation includes setting the test conditions. Taking W (tungsten) as an example, the target is Cu, the scanning angle is 40-42°, the step length is 0.03°, and the dwell time per step is 0.5s. 2 The ψ method uses a tilting method with φ angles of 0° and 180°, and a ψ angle range of 0 to 50°, with 5 to 10 equally spaced points. The collimator tube diameter is 0.03-0.5 mm. The measurement instrument is a Bruker D8 DISCOVER X-ray diffractometer.

[0110] 203. Testing process.

[0111] For example, the wire is maintained at different curvatures to test the test points, and the linear distance d of the wire legs is generally ≥ 3. Alternatively, when the wire is naturally curled, the linear distance of the wire legs of the cut wire can be measured as d0. When the wire is not obviously curled, the wire can be curled until it is clearly stressed, at which point the linear distance of the wire legs is d0.

[0112] Furthermore, the distance D when plastic deformation occurs is defined based on whether the radial stress changes suddenly (for example, the direction changes from positive to negative), that is, the wire foot distance when the wire material just undergoes plastic deformation. In addition, the distance d00 corresponding to the end curvature is defined to be less than or equal to D. At least one of the distances measured between the distance d0 corresponding to the initial curvature and the distance corresponding to the end curvature d00 is taken as the distance corresponding to the transition curvature, and the values ​​are recorded from large to small as: d1, d2...di, where i is a positive integer. The corresponding stress result is marked as: radial stress σ di and tangential stress τ di .

[0113] 204. Resilience analysis.

[0114] The measured linear distances are then used to calculate the radial and shear stress components using XRD. The toughness factor is then used to quantify and determine the toughness of wires of the same or different specifications. Specifically, the toughness factor includes R1-R4 as described in Example 1.

[0115] Specifically, the toughness factor evaluates toughness from three aspects: the initial shear stress value of bending (tangential stress corresponding to the initial curvature), the stress change rate, and the shear stress value at the end of bending.

[0116] ① Toughness factor R1 = |τ0|, τ0 is the initial shear stress of bending, that is, the shear stress corresponding to the initial curvature.

[0117] ②Toughness factor R2=K, K is τ d1 to τ d2 The rate of change of K = (τ d1 -τ d2 ) / τ d2 *100%, the greater the rate of change, the closer the external force applied to the wire is to the critical value during the bending stage.

[0118] ③ Toughness factor R3=|τ 00 |,τ 00 is the shear stress at the bending end, which is the shear stress measured at the corresponding end curvature. That is, the shear stress measured when the bending degree approaches or reaches plastic deformation.

[0119] ④ Toughness factor R4=|τ H |,τ H It is the stress measured after the sample is placed for H hours.

[0120] When testing wires of the same specification using the same bending method, if R = |R1+R3+R4| is large, it means the wire has relatively good toughness. When testing wires of different specifications using the same bending method, if R2 is large, it means the wire has relatively good toughness.

[0121] Through the technical solution, the multi-dimensional toughness characteristics of the thin-diameter wire can be accurately characterized, the quality of the wire is more comprehensively and accurately evaluated, and the toughness of the wires of the same specification or different specifications is comprehensively evaluated. Further, after the related data are sorted and accumulated, the quality of the wire can be quickly determined.

[0122] In order to facilitate understanding of the actual effect of the technical solutions provided in Embodiments 1 and 2 in analyzing different specifications of wires and the same specification of wires, the present application further provides some examples, as shown in Examples 1-3.

[0123] Example 1

[0124] Two tungsten wires A1 and A2 of a diameter specification of 0.18 mm have different straightness (curvatures). In theory, A2 has a poor straightness, indicating that the plastic deformation is more, that is, the toughness is poor, and the shear stress should be smaller (resistance is small) under the same curvature. Based on this, the technical solution provided by the present application is used to determine the distance d0 corresponding to the initial curvature by using the natural curvature, and to determine the distance D corresponding to the plastic deformation according to the radial stress of the mutation. The distances corresponding to multiple transition curvatures and the distance corresponding to the end curvature are measured: d1 = 80% d0, d2 = 50% d0, d00 = 30% d0 (the distance d00 corresponding to the end curvature is greater than D). The test results are shown in Table 1. It can be seen that R1, R3 and R4 of A1 are all greater than those of A2, which is consistent with the theory, that is, the conclusion of the wire toughness evaluation method provided by the present application for toughness evaluation and analysis of the same specification of wires completely conforms to the actual natural principle, and the effect is significant.

[0125] Table 1

[0126]

[0127] Example 2

[0128] Two molybdenum wires A3 and A4 of a diameter specification of 0.18 mm have different straightness (curvatures). A3 has a poor straightness, which theoretically indicates that the plastic deformation is more, which also indicates that the toughness is poor, and the shear stress should be smaller (resistance is small) under the same curvature. The distance d0 corresponding to the initial curvature is determined by using the natural curvature, and the distance D corresponding to the plastic deformation is determined according to the radial stress of the mutation. The distances corresponding to multiple transition curvatures and the distance corresponding to the end curvature are measured: d1 = 80% d0, d2 = 50% d0, d00 = 30% d0 (the distance d00 corresponding to the end curvature is greater than D). The test results are shown in Table 2. It can be seen that R1, R3 and R4 of A4 are all greater than those of A3, which is consistent with the theory, that is, the conclusion of the wire toughness evaluation method provided by the present application for toughness evaluation and analysis of the same specification of wires completely conforms to the actual natural principle, and the effect is significant.

[0129] Table 2

[0130]

[0131] Example 3

[0132] Two steel wires B1 and B2 with diameters of 0.040mm and 0.35mm. Theoretically, B1 has better toughness. The steel wire is curled to a stressed state to determine the initial curvature d0. According to the sudden change in radial stress, the curvature D corresponding to the plastic deformation is determined. A number of transition curvature corresponding distances and terminal curvature corresponding distances are measured: d1=90%d0, d2=80%d0, d00=70%d0 (terminal curvature corresponding distance>D). The test results are shown in Table 3. It can be seen that R2 of B1 is larger, which is consistent with the theory. That is, the conclusion of the wire toughness evaluation method provided in this application for toughness evaluation and analysis of wires of different specifications is completely consistent with actual natural principles, and the effect is significant.

[0133] Table 3

[0134]

[0135]

[0136] Through the above technical solution, the measured data is processed into radial stress components and shear stress components, and then through multi-dimensional analysis, a composite toughness index is obtained, which can accurately quantify and determine the toughness of wires of the same or different specifications, achieving a comprehensive and accurate toughness evaluation.

[0137] The technical solution provided in this application provides a new toughness evaluation method for wires with thinner diameters. The curvature of the wire under different bending conditions is selected to characterize different bending stages; the tangential stress that causes toughness fracture is used as the main analysis indicator. By analyzing the numerical value and change of the tangential stress at different stages, the multi-dimensional toughness characteristics of the wire are accurately characterized, and the quality of the wire is evaluated more comprehensively and accurately.

[0138] This application also provides a schematic diagram of a wire toughness evaluation device, see Figure 4 , the device comprises:

[0139] An acquisition module 401 is configured to acquire a curvature K of a target wire at a point to be measured when the target wire is symmetrically bent with different curvatures about a vertical line in a tangential direction of the point to be measured as an axis of symmetry;

[0140] The analysis module 402 is configured to determine, from the plurality of curvatures K of the test points, an initial curvature K0, an end curvature K2, and at least one transition curvature K1 between the initial curvature and the end curvature, wherein the initial curvature K0 and the end curvature K2 are measured before and after the target wire is symmetrically bent and plastically deformed, respectively; determine, by X-ray diffraction, the stresses of the test points of the target wire under the initial curvature K0, the transition curvature K1, and the end curvature K2, wherein the stresses at least include the tangential stress exerted on the wire; and determine the toughness characteristics of the target wire based on at least one of the tangential stress of the test point corresponding to the initial curvature K0, the tangential stress of the test point corresponding to the transition curvature K1, and the tangential stress of the test point corresponding to the end curvature K2.

[0141] Through the above technical solution, the multi-dimensional toughness characteristics of wires with finer diameters can be accurately characterized, and the quality of the wires can be evaluated more comprehensively and accurately.

[0142] It should be noted that the wire toughness evaluation device provided in the above embodiment only uses the division of the above functional modules as an example to illustrate the corresponding steps. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the wire toughness evaluation device provided in the above embodiment and the above-mentioned wire toughness evaluation method are based on the same concept. The specific implementation process is detailed in Method Examples 1 and 2, and will not be repeated here.

[0143] The wire toughness evaluation method provided in this application can be executed by any computing device. The computing device can be a terminal device such as a personal computer or a desktop computer, or it can be a server, a server cluster composed of multiple physical servers, or a distributed file system, or a cloud server cluster that provides basic cloud computing services such as cloud storage and cloud services, cloud databases, cloud computing, cloud functions, network services, cloud communications, middleware services, domain name services, security services, content delivery networks (CDNs), big data and artificial intelligence platforms. This application does not limit this.

[0144] An embodiment of the present application provides a computing device. Figure 5 This is a schematic diagram of the hardware structure of a computing device provided in an embodiment of the present application. Figure 5As shown, the computing device includes a processor 501, a memory 502, a bus 503, and a computer program stored in the memory 502 and executable on the processor 501. The processor 501 includes one or more processing cores. The memory 502 is connected to the processor 501 via the bus 503. The memory 502 is used to store program instructions. When the processor executes the computer program, all or part of the steps in the above-mentioned method embodiment provided in this application are implemented.

[0145] Furthermore, as an executable solution, the computing device may be a computer unit, which may be a computing device such as a desktop computer, a laptop, a PDA, or a cloud server. The computer unit may include, but is not limited to, a processor and a memory. Those skilled in the art will appreciate that the composition of the computer unit described above is merely an example of a computer unit and does not constitute a limitation of the computer unit. The computer unit may include more or fewer components than described above, or a combination of certain components, or different components. For example, the computer unit may also include input and output devices, network access devices, a bus, etc., which are not limited in the present embodiment.

[0146] Furthermore, as an executable solution, the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the computer unit and connects various parts of the entire computer unit using various interfaces and lines.

[0147] The memory can be used to store the computer programs and / or modules, and the processor implements the various functions of the computer unit by running or executing the computer programs and / or modules stored in the memory, and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system and at least one application required for a function; the data storage area can store data created based on the use of the mobile phone, etc. In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage device.

[0148] The present application also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, all or part of the steps of the wire material toughness evaluation method described above in the embodiment of the present application are implemented.

[0149] The present application also provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements all or part of the steps of the wire toughness evaluation method described above in the embodiment of the present application.

[0150] If the module / unit integrated in the above-mentioned computing device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the process in the above-mentioned wire toughness evaluation method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by the processor, it can implement the steps of the above-mentioned various method embodiments. Wherein, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory) and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction.

[0151] Although the present application has been specifically shown and described in conjunction with preferred embodiments, it should be understood by those skilled in the art that various changes in form and details may be made to the present application without departing from the spirit and scope of the present application as defined by the appended claims, and all such changes are within the scope of protection of the present application.

Claims

1. A method for evaluating wire toughness, characterized in that: The method comprises: Select any point on the target wire as the test point; When the target wire is symmetrically bent with a vertical line in the tangential direction of the test point as the symmetry axis, the curvature K of the test point under different curvatures is obtained; Determine an initial curvature K0, an end curvature K2, and at least one transition curvature K1 between the initial curvature and the end curvature from the plurality of curvatures K of the measured points, wherein the initial curvature K0 and the end curvature K2 are measured before and after the target wire material is symmetrically bent and plastically deformed, respectively; Using X-ray diffraction, determine the stress of the target wire at the test point under the initial curvature K0, the transition curvature K1 and the terminal curvature K2, wherein the stress at least includes the tangential stress of the wire; Determining the toughness characteristic of the target wire material according to at least one of the tangential stress at the test point corresponding to the initial curvature K0, the tangential stress at the test point corresponding to the transition curvature K1, and the tangential stress at the test point corresponding to the terminal curvature K2; Determining the toughness characteristic of the target wire material according to at least one of the tangential stress at the test point corresponding to the initial curvature K0, the tangential stress at the test point corresponding to the transition curvature K1, and the tangential stress at the test point corresponding to the terminal curvature K2 includes at least one of the following: Determine the value of the tangential stress at the measuring point corresponding to the initial curvature as a first toughness factor, wherein the first toughness factor characterizes the initial deformation degree of the wire material; arbitrarily selecting two tangential stress values ​​from the tangential stress at the measuring point corresponding to the initial curvature K0, the tangential stress at the measuring point corresponding to the transition curvature K1, and the tangential stress at the measuring point corresponding to the terminal curvature K2, and calculating the rate of change between the two tangential stress values ​​to obtain a second toughness factor, wherein the second toughness factor characterizes the stress resistance of the wire material; The value of the tangential stress at the measuring point corresponding to the end curvature K2 is determined as the third toughness factor, and the third toughness factor characterizes the durability of the wire material; Obtaining a residual stress at a test point of the target wire material after the target wire material is placed at the test point for a target time when the curvature of the test point is not zero, and determining the value of the residual stress as a fourth toughness factor, wherein the fourth toughness factor characterizes deformation recovery ability of the wire material; After determining the toughness characteristics of a first wire and a second wire of the same material but different specifications, the method further includes: Comparing the second toughness factors of the first wire material and the second wire material to obtain a first evaluation result, wherein in the first evaluation result, a larger value of the second toughness factor indicates relatively better toughness of the corresponding specification; After determining the toughness characteristics of the third and fourth wire materials of the same material and specification, the method further includes: Calculating the sum of the first toughness factor, the third toughness factor, and the fourth toughness factor for the third wire and the fourth wire respectively to obtain a toughness index of the third wire and a toughness index of the fourth wire; The toughness index of the third wire material and the toughness index of the fourth wire material are compared to obtain a second evaluation result. In the second evaluation result, a wire material with a larger toughness index has relatively better toughness.

2. The method for evaluating wire toughness according to claim 1, wherein: The determining of the initial curvature K0 from the curvatures K of the plurality of points to be measured comprises: If the wire segment of the target wire at the test point is not curled under no stress, the curvature K of the test point when the target wire is bent to the point where the tangential stress is greater than 0 is determined as the initial curvature K0; If the wire segment where the to-be-measured point of the target wire is located curls under an unstressed state, the curvature K of the to-be-measured point under the unstressed state is determined as the initial curvature K0.

3. The method for evaluating wire toughness according to claim 1, wherein: The determining of the initial curvature K0 from the curvatures K of the plurality of points to be measured comprises: The smallest curvature among the curvatures K of the plurality of points to be measured is determined as the initial curvature K0.

4. The method for evaluating wire toughness according to claim 1, wherein: The stress determined by the X-ray diffraction method also includes radial stress. Determining the end curvature K2 from the curvatures K of the plurality of points to be measured includes: During the symmetrical bending process, the curvature of the target wire at the point to be measured when the direction of the radial stress on the point to be measured changes is determined as the terminal curvature K2.

5. The method for evaluating wire toughness according to claim 1, wherein: The target wire material is a tough material, and the tough material includes a metal material, and the metal material includes an alloy of one or more of tungsten, molybdenum, and steel.

6. The method for evaluating wire toughness according to claim 1, wherein: The diameter φ of the target wire material meets the following conditions: 0.038±0.003mm≤φ≤0.39±0.03mm.

7. A wire toughness evaluation device, characterized in that: The device comprises: An acquisition module is used to obtain the curvature K of the target wire at the test point when the target wire is symmetrically bent with different curvatures around a vertical line in the tangential direction of the test point as the symmetry axis; An analysis module is configured to determine, from a plurality of curvatures K of the test points, an initial curvature K0, an end curvature K2, and at least one transition curvature K1 between the initial curvature and the end curvature, wherein the initial curvature K0 and the end curvature K2 are respectively measured before and after the target wire is symmetrically bent and plastically deformed; determine, by X-ray diffraction, the stress of the test point of the target wire under the initial curvature K0, the transition curvature K1, and the end curvature K2, wherein the stress at least includes the tangential stress exerted on the wire; and determine the toughness characteristics of the target wire based on at least one of the tangential stress of the test point corresponding to the initial curvature K0, the tangential stress of the test point corresponding to the transition curvature K1, and the tangential stress of the test point corresponding to the end curvature K2; Wherein, determining the toughness characteristic of the target wire material according to at least one of the tangential stress at the measuring point corresponding to the initial curvature K0, the tangential stress at the measuring point corresponding to the transition curvature K1, and the tangential stress at the measuring point corresponding to the terminal curvature K2 includes at least one of the following: Determine the value of the tangential stress at the measuring point corresponding to the initial curvature as a first toughness factor, wherein the first toughness factor characterizes the initial deformation degree of the wire material; arbitrarily selecting two tangential stress values ​​from the tangential stress at the measuring point corresponding to the initial curvature K0, the tangential stress at the measuring point corresponding to the transition curvature K1, and the tangential stress at the measuring point corresponding to the terminal curvature K2, and calculating the rate of change between the two tangential stress values ​​to obtain a second toughness factor, wherein the second toughness factor characterizes the stress resistance of the wire material; The value of the tangential stress at the measuring point corresponding to the end curvature K2 is determined as the third toughness factor, and the third toughness factor characterizes the durability of the wire material; Obtaining a residual stress at a test point of the target wire material after the target wire material is placed at the test point for a target time when the curvature of the test point is not zero, and determining the value of the residual stress as a fourth toughness factor, wherein the fourth toughness factor characterizes deformation recovery ability of the wire material; After determining the toughness characteristics of a first wire and a second wire of the same material but different specifications, a first evaluation result is obtained by comparing the second toughness factors of the first wire and the second wire. In the first evaluation result, a larger value of the second toughness factor indicates relatively better toughness of the corresponding specification. After determining the toughness characteristics of a third wire and a fourth wire of the same material and specification, respectively, calculating the sum of the first toughness factor, the third toughness factor, and the fourth toughness factor for the third wire and the fourth wire to obtain a toughness index of the third wire and a toughness index of the fourth wire; The toughness index of the third wire material and the toughness index of the fourth wire material are compared to obtain a second evaluation result. In the second evaluation result, a wire material with a larger toughness index has relatively better toughness.

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