A method for relieving stress of a polycrystalline diamond compact

Abstract

The present application relates to the technical field of superhard material, and discloses a kind of stress relief methods of polycrystalline diamond compact, comprising the following steps: S1: the preparation of vibrating component, multiple groups of PDC piece are combined into integral component A;S2: determine the process parameters of integral component A vibration aging;S3: full-automatic vibration aging treatment;Equipment is automatically operated according to the set parameters, and automatically stops;S4: stress evaluation after vibration aging;Wherein stress evaluation adopts qualitative evaluation mode, and the change of stress before and after PDC vibration aging is tested using XRD diffraction, vibration aging is applied to the field of PDC stress relief, and the method is short in time, low in cost, simple in operation, reduces stress, and improves the strength of PDC.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of superhard materials, in particular to a method for reducing residual stress of polycrystalline diamond compact. BACKGROUND

[0002] Polycrystalline diamond compact (PDC for short) is synthesized by polycrystalline diamond and tungsten carbide-cobalt hard alloy under superhigh pressure and high temperature. PDC superhard composite products have been widely used in many fields. Because the thermal expansion coefficients of diamond and hard alloy are very different, thermal residual stress is inevitably generated in the process of cooling after PDC is sintered under high pressure. The existence of residual stress reduces the strength of PDC, and the diamond layer is easy to collapse and even peel off from the substrate during use, thereby causing PDC to fail.

[0003] The current industry generally adopts the traditional thermal aging method to reduce the residual stress of PDC. Thermal aging requires a special heating furnace, which has large investment, large energy consumption and low efficiency. Most importantly, it is easy to cause thermal damage to PDC, thereby reducing the strength of PDC. Vibration aging is to apply alternating stress to the part, and the stress is superimposed on the residual stress of the part. When the superimposed stress reaches a certain value, plastic deformation occurs at the stress concentration site, which reduces the peak value of the residual stress at the site and strengthens the metal matrix. Therefore, vibration aging can eliminate stress and improve the strength of the part. The current vibration aging is mainly applied to the stress elimination of large components and welded parts in the steel industry, and does not cause thermal damage and deformation, and has the advantages of short aging period, high efficiency, energy saving and environmental protection. In view of the problems in the prior art, the present application first applies vibration aging to the field of PDC stress elimination, which reduces the stress without damaging the strength of PDC. SUMMARY

[0004] The present application aims to overcome the defects of the prior art that the traditional thermal aging method is used to reduce the residual stress of PDC, and proposes a method for reducing the residual stress of polycrystalline diamond compact. The method applies vibration aging to the field of PDC stress elimination, which is time-saving, low-cost and easy to operate, reduces the stress and improves the strength of PDC.

[0005] The purpose of the present application is achieved by the following measures:

[0006] A polycrystalline diamond compact stress relief method, comprising the following steps:

[0007] S1: preparing a vibration component, combining a plurality of PDC pieces and clamps into an integral component A;

[0008] S2: determining the process parameters of vibration aging of the integral component A;

[0009] S3: full automatic vibration aging treatment; the device is automatically operated according to the set parameters and automatically stopped;

[0010] S4: stress evaluation after vibration aging; wherein the stress evaluation adopts a qualitative evaluation method, and the stress change of the PDC before and after vibration aging is tested by XRD diffraction.

[0011] In order to further optimize the present application, the following technical solutions can be preferred:

[0012] Preferably, the step S1 further comprises:

[0013] S101: preparing a plurality of PDC pieces requiring aging treatment, and fixing them in a special clamp to ensure rigid contact between each composite piece and between the clamp and the composite piece, forming a whole component A; wherein the rigid contact is that no relative displacement occurs during vibration;

[0014] S102: analyzing and judging the required effective vibration mode according to the material, size, stress distribution and the like of the component A prepared in the step S101;

[0015] S103: elastically supporting the component A prepared in the step S101 near the nodal line of the effective vibration mode according to the predicted effective vibration mode result in the step S102;

[0016] S104: installing an exciter at the wave crest during vibration of the component A prepared in the step S101;

[0017] S105: installing an acceleration sensor at the edge or end of the component A prepared in the step S101.

[0018] Preferably, the S101 clamp is a steel plate, and the tops of the plurality of PDC pieces are fixed on the steel plate through a screw cover plate to ensure rigid connection.

[0019] Preferably, the steel plate has a thickness of 35-40 mm, a length of 2 m and a width of 1 m.

[0020] Preferably, the S101 clamp is a drawer type box body, and a baffle for moving the fixed PDC pieces is movably arranged on one side of the box body.

[0021] Preferably, the support point of the elastic support in the step S103 is the position with the minimum amplitude in the effective vibration mode.

[0022] Preferably, the step S2 specifically comprises:

[0023] S201: the vibration aging device automatically detects the inherent resonance frequency of the aging component in a scanning manner, selects a sub-resonance zone as the resonance peak of the effective vibration mode, and determines the sub-resonance zone in the frequency range corresponding to 1 / 3-2 / 3 of the resonance peak height;

[0024] S202: Vibration aging treatment time 0.5-3 hours; vibration acceleration is controlled at 20-100 m / s during vibration aging process 2 ;

[0025] S203: The component is excited at an effective frequency.

[0026] Preferably, the plurality of PDC pieces are stacked and arranged side by side in step S101.

[0027] Advantages of the present application:

[0028] 1. The stress relief method proposed by the present application can reduce stress and improve strength.

[0029] 2. The method is suitable for production application, has high efficiency, small investment, convenient operation, energy saving and environmental protection.

[0030] 3. In the present application, residual stress is qualitatively described by XRD. No phase change occurs before and after vibration aging, only the right shift of diffraction peak occurs. According to Bragg formula 2dsinθ=nλ, the diffraction angle increases and the lattice distance decreases, that is, the tensile stress decreases or changes into beneficial compressive stress after vibration aging of the sample. Scanning electron microscope analysis of the sample before and after vibration aging shows that no microstructure morphology change occurs. Drop hammer impact strength comparison of the samples subjected to vibration aging and thermal aging shows that the average impact strength of the sample after vibration aging is 12.5% higher than that of the sample after thermal aging. The processing method has high efficiency: vibration aging of a batch takes tens of minutes, and thermal aging takes tens of hours, which greatly improves the processing efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a step flow chart for stress relief of polycrystalline diamond compact

[0032] Figure 2 is a first component schematic diagram of polycrystalline diamond compact formation.

[0033] Figure 3 is Figure 2 top view of

[0034] Figure 4 is XRD diffraction pattern before and after vibration aging.

[0035] Wherein: 100-component, 101-exciter, 102-acceleration sensor, 103-elastic support. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0037] Among them, the polycrystalline diamond compact (PDC) belongs to a new type of functional material, which is sintered from diamond powder and hard alloy substrate under ultra-high pressure and high temperature, has high hardness, high wear resistance and thermal conductivity of diamond, and has strength and impact toughness of hard alloy, and is an ideal material for manufacturing cutting tools, drilling bits and other wear-resistant tools.

[0038] The composite material with a polycrystalline diamond thin layer attached and bonded on a hard alloy substrate is called a diamond compact, and the code is PDC. The diamond compact has both the extremely high wear resistance of polycrystalline diamond and the high impact resistance of hard alloy, and the diamond layer can always maintain a sharp cutting edge, so it is very good in soft to medium-hard strata in oil and geological drilling. The diamond content in the compact is as high as 99%, so the diamond layer has extremely high hardness and excellent wear resistance, and its Knoop hardness is (6.5-7) x 104 megapascals or even higher. The thickness is very thin, generally controlled at about 0.5-1 millimeters. It is vertically inserted and welded on a drill bit, and the cutting edge is sharp and always self-sharpening, also known as a micro-cutting tool drill bit.

[0039] As shown in Figures 1-4 ,

[0040] Embodiment 1

[0041] A polycrystalline diamond compact stress relief method, comprising the following steps:

[0042] S1: preparation of a vibration member, combining multiple groups of PDC pieces with a clamp into an integral member A100;

[0043] In step S1, it further comprises:

[0044] S101: preparing multiple groups of PDC pieces that need to be aged, arranging them in stacks and side by side, and fixing them in a special clamp to ensure rigid contact between each compact and between the clamp and the compacts, forming an integral member A; the rigid contact is that there is no relative displacement during vibration;

[0045] S102: analyzing and judging the required effective vibration mode according to the material, size, stress distribution, etc. of the member A prepared in step S101;

[0046] S103: supporting the component A prepared in step S101 elastically around the nodal line of the effective mode according to the result of the effective mode predicted in step S102; the supporting point of the elastic support in step S103 is the position of the minimum amplitude in the effective mode, and the elastic support in the embodiment uses a rubber pad.

[0047] S104: installing the exciter at the wave crest when the component A prepared in step S101 is vibrating;

[0048] S105: installing the acceleration sensor at the edge or end of the component A prepared in step S101.

[0049] S2: determining the process parameters of the vibration aging of the whole component A;

[0050] In step S2, specifically comprising:

[0051] S201: the vibration aging device automatically detects the natural resonance frequency of the component to be aged in a scanning manner, selects a sub-resonance region as the resonance peak of the effective mode, and determines the sub-resonance region in the frequency range corresponding to 1 / 3-2 / 3 of the height of the resonance peak;

[0052] S202: the vibration aging time is 12 min; the vibration acceleration is controlled to be 20 m / s during the vibration aging process 2 ;

[0053] S203: exciting the component at the effective frequency.

[0054] S3: full-automatic vibration aging treatment; the device automatically runs and stops according to the set parameters;

[0055] S4: stress evaluation after vibration aging; the stress evaluation adopts a qualitative evaluation method, and the XRD diffraction is used to test the stress change of the PDC before and after vibration aging.

[0056] Embodiment 2:

[0057] A stress relieving method of a polycrystalline diamond compact, comprising the following steps:

[0058] S1: preparing the vibration component, combining a plurality of groups of PDC pieces with a clamp into a whole component A100;

[0059] In step S1, specifically further comprising:

[0060] S101: preparing a plurality of groups of PDC pieces to be aged in a stack and side-by-side arrangement, fixing them in a special clamp, ensuring rigid contact between each composite piece and between the clamp and the composite piece, forming a whole component A; wherein the rigid contact is that there is no relative displacement during vibration;

[0061] S102: judging the effective vibration mode according to the material, size, stress distribution and the like of the component A prepared in step S101;

[0062] S103: elastically supporting the component A prepared in step S101 near the nodal line of the effective vibration mode according to the result of the effective vibration mode predicted in step S102; the support point of the elastic support in step S103 is the position of the minimum amplitude in the effective vibration mode, and the elastic support in the embodiment uses a rubber pad.

[0063] S104: installing the exciter at the wave crest when the component A prepared in step S101 vibrates;

[0064] S105: installing the acceleration sensor at the edge or end of the component A prepared in step S101.

[0065] S2: determining the process parameters of the vibration aging of the whole component A;

[0066] In step S2, specifically comprising:

[0067] S201: the vibration aging equipment automatically detects the natural resonance frequency of the component to be aged in a scanning manner, selects the sub-resonance region as the resonance peak of the effective vibration mode, and determines the sub-resonance region in the frequency range corresponding to 1 / 3-2 / 3 of the height of the resonance peak;

[0068] S202: the vibration aging treatment time is 0.2-3 hours; the vibration acceleration is controlled to be 20-100 m / s during the vibration aging process 2 ;

[0069] S203: exciting the component at the effective frequency.

[0070] S3: full-automatic vibration aging treatment; the equipment automatically runs and automatically stops according to the set parameters;

[0071] S4: stress evaluation after vibration aging; wherein the stress evaluation adopts a qualitative evaluation method, and the XRD diffraction is used to test the stress change of the PDC before and after vibration aging.

[0072] Embodiment 3:

[0073] A stress relieving method of a polycrystalline diamond compact, comprising the following steps:

[0074] S1: preparation of a vibrating component, combining a plurality of PDC pieces with a clamp into a whole component A100;

[0075] In step S1, specifically further comprising:

[0076] S101: Prepare multiple groups of PDC pieces that need to be treated by time effect, arrange them in stacks and side by side, fix them in a special fixture, ensure rigid contact between each composite piece and between the fixture and the composite piece, and form an overall component A; wherein rigid contact is that there is no relative displacement during vibration;

[0077] S102: Analyze and determine the required effective vibration mode according to the material, size, stress distribution, etc. of the component A prepared in step S101;

[0078] S103: According to the effective vibration mode predicted in step S102, elastically support the component A prepared in step S101 near the nodal line of the effective vibration mode; the support point of the elastic support in step S103 is the position with the smallest amplitude in the effective vibration mode, and in this embodiment, the elastic support uses rubber pads.

[0079] S104: Install an exciter at the wave peak of the component A prepared in step S101 during vibration;

[0080] S105: Install an acceleration sensor at the edge or end of the component A prepared in step S101.

[0081] S2: Determine the process parameters of the vibration time effect of the overall component A;

[0082] Wherein step S2, specifically includes:

[0083] S201: The vibration time effect equipment automatically detects the natural resonance frequency of the time effect component in a scanning manner, selects the sub-resonance area as the resonance peak of the effective vibration mode, and determines the sub-resonance area in the frequency range corresponding to 1 / 3-2 / 3 of the resonance peak height;

[0084] S202: The vibration time effect processing time is 15 min; the vibration acceleration is controlled to be 35 m / s during the vibration time effect process 2 ;

[0085] S203: Excite the component at the effective frequency.

[0086] S3: Full-automatic vibration time effect treatment; the equipment automatically runs and stops according to the set parameters;

[0087] S4: Stress evaluation after vibration time effect; wherein the stress evaluation adopts a qualitative evaluation method, and XRD diffraction is used to test the stress change of PDC before and after vibration time effect.

[0088] Example 4:

[0089] A method for removing stress from a polycrystalline diamond compact, comprising the following steps:

[0090] S1: Preparation of a vibrating component, combining multiple groups of PDC pieces with a fixture into an overall component A100;

[0091] Wherein step S1, specifically further comprises:

[0092] S101: Prepare multiple groups of PDC pieces that need to be treated by aging, arrange them in stacks and side by side, fix them in a special fixture, ensure rigid contact between each composite piece and between the fixture and the composite piece, and form an overall component A; wherein rigid contact is that there is no relative displacement during vibration;

[0093] S102: Analyze and determine the required effective vibration mode according to the material, size, stress distribution, etc. of the component A prepared in step S101;

[0094] S103: According to the effective vibration mode result predicted in step S102, elastically support the component A prepared in step S101 near the nodal line of the effective vibration mode; the support point of the elastic support in step S103 is the position of the minimum amplitude in the effective vibration mode, and in this embodiment, the elastic support uses rubber pads.

[0095] S104: Install the exciter at the wave peak of the component A prepared in step S101 during vibration;

[0096] S105: Install the acceleration sensor 102 at the edge or end of the component A prepared in step S101.

[0097] S2: Determine the process parameters of the vibration aging of the overall component A;

[0098] Wherein step S2, specifically comprises:

[0099] S201: The vibration aging equipment automatically detects the natural resonance frequency of the aged component in a scanning manner, selects the sub-resonance region as the resonance peak of the effective vibration mode, and determines the sub-resonance region in the frequency range corresponding to 1 / 3-2 / 3 of the resonance peak height;

[0100] S202: The vibration aging treatment time is 1 hour; the vibration acceleration is controlled to be 50 m / s during the vibration aging process 2 ;

[0101] S203: Excite the component at the effective frequency.

[0102] S3: Full-automatic vibration aging treatment; the equipment automatically runs and stops according to the set parameters;

[0103] S4: Stress evaluation after vibration aging; wherein the stress evaluation adopts a qualitative evaluation method, and the XRD diffraction is used to test the stress change of the PDC before and after vibration aging.

[0104] Example 5:

[0105] A method for removing stress from a polycrystalline diamond compact, comprising the following steps:

[0106] S1: preparing the vibration member, combining multiple groups of PDC pieces with a clamp into an integral member A100;

[0107] In step S1, it further specifically comprises:

[0108] S101: preparing multiple groups of PDC pieces that need to be treated by aging in a stack and side-by-side arrangement, fixing them in a special clamp, ensuring rigid contact between each composite piece and between the clamp and the composite piece, and forming an integral member A; the rigid contact is that there is no relative displacement during vibration;

[0109] S102: judging the required effective vibration mode according to the material, size, stress distribution, etc. of the member A prepared in step S101;

[0110] S103: according to the effective vibration mode result predicted in step S102, elastically supporting the member A prepared in step S101 near the nodal line of the effective vibration mode; the support point of the elastic support in step S103 is the position of the minimum amplitude in the effective vibration mode, and the elastic support 103 in this embodiment uses a rubber pad.

[0111] S104: installing an exciter at the wave crest of the member A prepared in step S101 during vibration;

[0112] S105: installing an acceleration sensor at the edge or end of the member A prepared in step S101.

[0113] S2: determining the process parameters of the vibration aging of the integral member A;

[0114] In step S2, it specifically comprises:

[0115] S201: the vibration aging equipment automatically detects the natural resonance frequency of the aging member in a scanning manner, selects a sub-resonance zone as the resonance peak of the effective vibration mode, and determines the sub-resonance zone in the frequency range corresponding to 1 / 3-2 / 3 of the height of the resonance peak;

[0116] S202: the vibration aging treatment time is 3 hours; the vibration acceleration is controlled to be 100 m / s during the vibration aging process 2 ;

[0117] S203: exciting the member at the effective frequency.

[0118] S3: full-automatic vibration aging treatment; the equipment automatically runs and stops according to the set parameters;

[0119] S4: stress evaluation after vibration aging; the stress evaluation adopts a qualitative evaluation method, and the XRD diffraction is used to test the stress change of the PDC before and after vibration aging.

[0120] As a form of clamp, the clamp for the webbing in S101 is a steel plate with a thickness of 35-40mm, a length of 2m and a width of 1m. The tops of multiple groups of PDC sheets are fixed to the steel plate by screw covers to ensure a rigid connection.

[0121] like Figure 2 、 3 As shown, as another type of fixture, the S101 fixture is a drawer-type box, and a baffle for moving and fixing the PDC sheet is movably provided on one side of the box.

[0122] like Figure 3 As shown in the figure, there is no change in the phase after vibration aging, and the diffraction peak of the binder phase shifts significantly to the right, indicating that the lattice spacing becomes smaller. The macroscopic explanation is that the compressive stress increases or the tensile stress is transformed into compressive stress. It is well known that compressive stress is beneficial to the strength improvement of materials. By comparison, the impact strength of PDC after vibration aging is increased by about 10%, which proves that vibration aging is effective in eliminating PDC stress.

[0123] A drop hammer impact test was performed on the product after vibration aging and thermal aging in this embodiment:

[0124] Experimental method: The industry-standard drop hammer impact method was used to compare the two aging methods: 5 samples were taken from each method and marked as #1, #2, #3, #4, and #5 respectively; each sample was impacted at the same impact energy until it was destroyed. The comparative experimental data is shown in Table 1.

[0125] Table 1 Test data of vibration aging and thermal aging impact strength

[0126]

[0127] The above data show that the average number of impact failures of the five pieces were 10.8 and 9.6 respectively, and the vibration aging impact strength increased by 12.5% ​​compared with the thermal aging strength.

[0128] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for stress relieving of a polycrystalline diamond compact, characterized by, The method comprises the following steps: S1: preparation of the vibrating component, combining multiple groups of PDCs with a fixture into a whole component A; S2: determining the process parameters of the vibration aging of the whole component A; The step S2 specifically comprises: S201: the vibration aging equipment automatically detects the natural resonance frequency of the component to be aged in a scanning manner, selects a sub-resonance area as the resonance peak of the effective vibration mode, and determines the sub-resonance area in the frequency range corresponding to 1 / 3-2 / 3 of the height of the resonance peak; S202: Vibration aging treatment time 0.5 hours to 3 hours; vibration acceleration is controlled at 20-100 m / s during vibration aging process 2 ; S203: exciting the component at the effective frequency; S3: full-automatic vibration aging treatment; the equipment automatically runs and stops according to the set parameters; S4: stress evaluation after vibration aging; The stress evaluation adopts a qualitative evaluation method, and the XRD diffraction is used to test the stress change of the PDC before and after vibration aging.

2. The method according to claim 1, wherein: The step S1 specifically further comprises: S101: preparing multiple groups of PDCs to be aged, fixing the PDCs in a fixture, ensuring rigid contact between the multiple composite pieces and between the fixture and the composite pieces, and forming a whole component A; wherein the rigid contact is that no relative displacement occurs during vibration; S102: judging the required effective vibration mode according to the material, size and stress distribution analysis of the component A prepared in the step S101; S103: elastically supporting the component A prepared in the step S101 at the position of the minimum amplitude of the effective vibration mode according to the predicted effective vibration mode result in the step S102; S104: installing an exciter at the wave peak of the component A prepared in the step S101 during vibration; S105: installing an acceleration sensor at the edge of the component A prepared in the step S101.

3. The method according to claim 2, wherein: The fixture in the step S101 is a steel plate, and the top of the multiple groups of PDCs is fixed on the steel plate through a screw cover plate to ensure rigid connection.

4. The method according to claim 3, wherein: The thickness of the steel plate is 35-40 mm, the length is 2 m, and the width is 1 m.

5. The method of claim 2, wherein: The fixture in the step S101 is a drawer type box, and a baffle for fixing the PDCs is movably arranged on one side of the box.

6. The method of claim 2, wherein: The multiple groups of PDCs in the step S101 are stacked and arranged side by side.

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