Electrode for electric spark deposition, application of electrode, wear-resistant coating and preparation method and application of wear-resistant coating

Abstract

The invention belongs to the technical field of surface engineering, and particularly relates to an electrode for electric spark deposition, application of the electrode, a wear-resistant coating and a preparation method and application of the wear-resistant coating. According to the electrode provided by the invention, the coating is prepared by adopting an electric spark deposition method, and the Mo element in the coating can improve the lubricating performance and reduce the friction coefficient between the coating and a metal mold; the rare earth elements in the coating can refine grains, so that the coating has good mechanical properties, good metallurgical bonding is formed between the coating and a matrix, and the hardness and the adhesive wear resistance of the coating are further improved. Furthermore, the invention also provides a preparation method of the wear-resistant coating, an ultrasonic process is applied in the deposition process, and ultrasonic impact is utilized to generate pressure stress, so that the deposited tensile stress is counteracted, the residual stress of the coating is eliminated, and the hardness and wear resistance of the coating are further improved. The wear-resistant coating is applied to the surface treatment of the rim mold, so that the service life of the mold can be further prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of surface engineering, and in particular relates to an electrode for electric spark deposition and application thereof, a wear-resistant coating and a preparation method and application thereof. Background Art

[0002] The wheel rim mold is a typical cold drawing mold. Common failure modes are top corner wear and drawing surface scratches, which are caused by typical adhesive wear between iron molecules. The wheel rim and the mold are made of the same steel product. The van der Waals force (intermolecular attraction) between the two is strong, and friction pressure welding often occurs. Surface bite causes scratches on the mold and the workpiece, which causes defects on the mold surface in the long run, and the deformation of the workpiece does not meet the requirements.

[0003] The mold surface needs to be polished regularly before it can be used. Polishing the drawing mold once will remove about 0.3 to 0.5 mm. After 2 to 3 times, the rim mold cannot be used anymore. In order to solve the problem of adhesion and wear of the rim mold, foreign countries use physical vapor deposition technology to prepare ceramic films such as TiN on the surface of the cold drawing mold to improve the surface hardness of the mold and extend the service life of the mold. However, the rim mold of the agricultural machinery wheel is large and heavy, which is not suitable for physical vapor deposition technology. Summary of the invention

[0004] The object of the present invention is to provide an electrode for electrospark deposition and its application, a wear-resistant coating and its preparation method and application. The electrode provided by the present invention can perform surface treatment and strengthening on a large wheel rim mold by electrospark deposition, thereby improving the mold surface hardness and extending the mold service life.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The invention provides an electrode for electric spark deposition. The electrode comprises the following components in terms of mass percentage: 35.0-45.0% TiN, 35.0-40.0% TiC, 5.0-10.0% Mo, 5.0-10.0% Co, 5.0-10.0% Ni and 0.01-1% rare earth elements.

[0007] Preferably, the rare earth element includes one or more of Y, La, Sc, Ce, Pr and Nd.

[0008] Preferably, the electrode for electrospark deposition consists of a substrate and a hard phase, the substrate consists of Co, Ni, Mo and rare earth elements, and the hard phase consists of TiN and TiC.

[0009] Preferably, the length of the electrode for electrospark deposition is 100-120 mm, the width is 3-7 mm, and the thickness is 1-2.5 mm.

[0010] The present invention also provides the use of the electrode for electrospark deposition described in the above technical solution in the preparation of a wear-resistant coating.

[0011] The present invention also provides a method for preparing a wear-resistant coating, comprising the following steps:

[0012] The electrode for electrospark deposition described in the above technical solution is used as a working electrode, and ultrasonic electrospark deposition is used to deposit on the surface of the substrate to obtain the wear-resistant coating.

[0013] Preferably, the ultrasonic electrospark deposition condition parameters include: voltage of 60-110V, vibration frequency of 20000Hz, amplitude of 40μm, and discharge capacitance of 10-30μF.

[0014] The present invention also provides a wear-resistant coating prepared by the preparation method described in the above technical solution, wherein the wear-resistant coating consists of a matrix and a hard phase, the matrix consists of Co, Ni, Mo and rare earth elements, and the hard phase consists of TiN and TiC.

[0015] Preferably, the wear-resistant coating has a width of 3 to 7 mm and a thickness of 10 to 15 μm;

[0016] The microhardness of the wear-resistant coating is 1000-1200 HV, and the surface roughness Ra is 1.0-2.0 μm.

[0017] The present invention also provides application of the wear-resistant coating described in the above technical solution in a wheel rim mold.

[0018] The present invention provides an electrode for electrospark deposition, which comprises the following components in terms of mass percentage: 35.0-45.0% TiN, 35.0-40.0% TiC, 5.0-10.0% Mo, 5.0-10.0% Co, 5.0-10.0% Ni and 0.01-1% rare earth elements. The electrode provided by the present invention is used as a working electrode and an electrospark deposition method is adopted to prepare a coating, wherein the Mo element in the coating can increase the lubrication performance and reduce the friction coefficient between the coating and the metal mold; the rare earth element in the coating can refine the grains, so that the coating has good mechanical properties, forms a good metallurgical bond with the substrate, and thus improves the hardness and adhesive wear resistance of the coating.

[0019] The present invention also provides a method for preparing a wear-resistant coating, comprising the following steps: using the electrode described in the above technical solution as a working electrode, and depositing on the surface of a substrate by ultrasonic electric spark deposition to obtain the wear-resistant coating. The present invention applies an ultrasonic process during the deposition process, uses ultrasonic impact to generate compressive stress, offsets the tensile stress of the deposition, eliminates the residual stress of the coating, and further improves the hardness and wear resistance of the coating.

[0020] The present invention also provides the application of the wear-resistant coating described in the above technical solution in a wheel rim mold. The present invention uses the wear-resistant coating to strengthen the surface of the wheel rim mold, avoids shutdown and polishing due to surface scratches, prolongs the service life of the mold, and improves the production efficiency of the wheel rim. In the same time, the number of wheel rims produced is increased by more than 10 times; it not only saves downtime and reduces the use of spare molds, but also improves production efficiency and product consistency, and has significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the ultrasonic deposition gun in the present invention;

[0022] Figure 2 A schematic diagram of the process of ultrasonic electrospark deposition in the present invention;

[0023] Figure 3 is a cross-sectional metallographic image of the coating obtained in Example 1;

[0024] Among them, 1-working electrode, 2-clamping screw, 3-heat sink, 4-fastening screw, 5-positive electrode of power supply, 6-amplitude transformer, 7-transducer, 8-ultrasonic deposition gun housing, 9-workpiece to be deposited. DETAILED DESCRIPTION

[0025] The invention provides an electrode for electric spark deposition. The electrode comprises the following components in terms of mass percentage: 35.0-45.0% TiN, 35.0-40.0% TiC, 5.0-10.0% Mo, 5.0-10.0% Co, 5.0-10.0% Ni and 0.01-1% rare earth elements.

[0026] In terms of mass percentage, the electrode for electrospark deposition provided by the present invention includes 35.0-45.0% TiN, specifically 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%.

[0027] In terms of mass percentage, the electrode for electrospark deposition provided by the present invention comprises 35.0-40.0% TiC, specifically 35%, 36%, 37%, 38%, 39%, 40%.

[0028] In terms of mass percentage, the electrode for electrospark deposition provided by the present invention comprises 5.0-10.0% Mo, specifically 5%, 6%, 7%, 8%, 9%, 9.9%, and 10%.

[0029] In terms of mass percentage, the electrode for electrospark deposition provided by the present invention comprises 5.0-10.0% Co, specifically 5%, 6%, 7%, 8%, 9%, 10%.

[0030] In terms of mass percentage, the electrode for electrospark deposition provided by the present invention includes 5.0-10.0% Ni, specifically 5%, 6%, 7%, 8%, 9%, 9.9%, and 10%.

[0031] In terms of mass percentage, the electrode for electrospark deposition provided by the present invention includes 0.01-1% of rare earth elements, specifically 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%. In the present invention, the rare earth elements preferably include one or more of Y, La, Sc, Ce, Pr and Nd.

[0032] In the present invention, the electrode for electrospark deposition is preferably composed of a matrix and a hard phase, the matrix is ​​preferably composed of Co, Ni, Mo and rare earth elements, and the hard phase is preferably composed of TiN and TiC.

[0033] In the present invention, the length of the electrode for electrospark deposition is preferably 100 to 120 mm, the width is preferably 3 to 7 mm, more preferably 5 to 6 mm, and the thickness is preferably 1 to 2.5 mm.

[0034] The present invention also provides the use of the electrode for electrospark deposition described in the above technical solution in the preparation of a wear-resistant coating.

[0035] The present invention also provides a method for preparing a wear-resistant coating, comprising the following steps:

[0036] The electrode for electrospark deposition described in the above technical solution is used as a working electrode, and ultrasonic electrospark deposition is used to deposit on the surface of the substrate to obtain the wear-resistant coating.

[0037] In the present invention, the condition parameters of the ultrasonic spark deposition preferably include: voltage of 60 to 110 V, vibration frequency of 20,000 Hz, amplitude of 40 μm, and discharge capacitance of 10 to 30 μF. In the present invention, the ultrasonic spark deposition is preferably carried out in an inert atmosphere, and the inert atmosphere is preferably argon. In the present invention, the substrate preferably includes a rim mold.

[0038] In the present invention, the specific process of ultrasonic electric spark deposition is preferably: connect the positive electrode of the power supply to the rear end of the electrode clamping part of the ultrasonic deposition gun, insert the working electrode into the clamping part, and tighten the clamping screw; connect the negative electrode of the power supply to the workpiece to be deposited, start the power supply and the ultrasonic generator, contact the end of the working electrode with the surface of the workpiece, the working electrode starts to discharge, and deposition is performed under limited conditions. The end of the working electrode is in a contact and disconnected state with the surface of the workpiece, and the charging and discharging conditions of the electric spark deposition power supply are met. In the present invention, the ultrasonic deposition gun is preferably installed on the wrist of an industrial robot, and the workpiece to be deposited is preferably installed on a positioner to realize automated production and further improve the deposition uniformity of the coating.

[0039] In the present invention, the structural schematic diagram of the ultrasonic deposition gun is as follows Figure 1 As shown, 1 is a working electrode, 2 is a clamping screw, 3 is a heat sink, 4 is a fastening screw, 5 is a positive electrode of a power supply, 6 is a horn, 7 is a transducer, and 8 is a housing of an ultrasonic deposition gun.

[0040] In the present invention, the process schematic diagram of ultrasonic electrospark deposition is as follows: Figure 2 As shown, 1 is a working electrode, 2 is a clamping screw, 3 is a heat sink, 4 is a fastening screw, 5 is a positive electrode of a power supply, 6 is an amplitude transformer, 7 is a transducer, 8 is a housing of an ultrasonic deposition gun, and 9 is a workpiece to be deposited.

[0041] The present invention also provides a wear-resistant coating prepared by the preparation method described in the above technical solution, wherein the wear-resistant coating consists of a matrix and a hard phase, the matrix consists of Co, Ni, Mo and rare earth elements, and the hard phase consists of TiN and TiC.

[0042] In the present invention, the composition of the wear-resistant coating is preferably the same as that of the electrode.

[0043] In the present invention, the width of the wear-resistant coating is preferably 3-7 mm, more preferably 5-6 mm, and the thickness is preferably 10-15 μm. In the present invention, the microhardness of the wear-resistant coating is preferably 1000-1200 HV, and the surface roughness Ra is preferably 1.0-2.0 μm.

[0044] The present invention also provides application of the wear-resistant coating described in the above technical solution in a wheel rim mold.

[0045] Unless otherwise specified, the materials and equipment used in the present invention are all commercially available products in the art.

[0046] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] Example 1

[0048] use Figure 2 The schematic diagram of the process shown is deposited on the mold surface;

[0049] In this embodiment, the electrode includes the following components in percentage by mass: TiN 45.0%, TiC 35.0%, Mo 9.9%, Co 5.0%, Ni 5.0% and rare earth element Nd 0.1%; the length of the electrode is 100 mm, the width is 5 mm and the thickness is 1 mm;

[0050] Connect the positive electrode of the power supply to the rear end of the electrode clamping part of the ultrasonic deposition gun, insert the working electrode into the clamping part, and tighten the clamping screw; connect the negative electrode of the power supply to the mold, and contact the end of the working electrode to the mold surface; install the ultrasonic deposition gun on the wrist of the industrial robot, and wait for the mold to be installed on the positioner;

[0051] The electric spark deposition power supply and the ultrasonic generator are started, the working electrode begins to discharge, and the electrode end is in contact and disconnection with the mold surface, meeting the charging and discharging conditions of the electric spark deposition power supply, wherein the condition parameters of ultrasonic electric spark deposition are: voltage of 100V, vibration frequency of 20000Hz, amplitude of 40μm, and discharge capacitance of 30μF; the ultrasonic electric spark deposition is carried out under argon protection to obtain a wear-resistant coating, with a single coating width of 5mm and a thickness of 15μm. Figure 3 This is a cross-sectional metallographic image of a single-layer coating. It can be seen that the coating thickness is uniform and there are few defects.

[0052] After one layer of deposition is completed, the ultrasonic electrospark deposition gun moves down 4mm, overlaps with the previous coating by 1mm, and starts to deposit the second layer. The above process is repeated until the entire mold surface is strengthened, that is, the preparation of a single layer of coating on the entire mold surface is completed; the above process is repeated to deposit 3 layers of coating on the mold surface.

[0053] Example 2

[0054] The wear-resistant coating was prepared in the manner of Example 1, except that the electrode in this example included the following components in percentage by mass: TiN 40.0%, TiC 40.0%, Mo 5%, Co 5.0%, Ni 9.9% and rare earth element Nd 0.1%.

[0055] Performance Testing

[0056] Test Example 1

[0057] According to the standard T / CSTM 00646.1-2021 "Metallic material pin-disc friction and wear test Part 1: Room temperature friction and wear test method", the friction and wear properties of the coating obtained in the embodiment under different test times and loads were measured. The friction and wear test parameters are designed according to the actual working conditions of the mold. The agricultural machinery wheel rim mold works under a 500-ton to 1,000-ton press, and the force area is about 0.25m 2 , the corresponding test loads are 350N and 700N, the friction pair is GCr15 with a diameter of 4.8mm, the disc sample size is 30mm (diameter) × 5mm, and the rotation speed is 20rpm. Before and after the friction and wear test, the mass of the sample was measured by an XPE504 analytical balance with an accuracy of 0.1mg. Finally, the wear scar was observed using a NexView three-dimensional white light interferometer profiler, and the wear scar depth was calculated. The test results are as follows:

[0058] (1) A friction and wear test was carried out for 480 min under a load of 350 N. The average friction coefficient of the coating obtained in Example 1 was 0.615, and the average friction coefficient of the quenched GCr15 was 0.66, which was 7% lower than that of the quenched GCr15.

[0059] In the friction and wear test for 480 min under a load of 350 N, the wear amount of the coating obtained in Example 1 was 4.3 mg, and the wear amount of the quenched GCr15 was 13 mg, which was about 67% lower than that of the quenched GCr15;

[0060] (2) A friction and wear test was carried out for 480 min under a load of 700 N. The average friction coefficient of the coating obtained in Example 2 was 0.578, and the average friction coefficient of the quenched GCr15 was 0.615, which was 6% lower than that of the quenched GCr15.

[0061] The friction and wear test was carried out for 480 min under a load of 700 N. The wear amount of the coating obtained in Example 2 was 8.2 mg, and the wear amount of the quenched GCr15 was 29.3 mg, which was reduced by about 72% compared with the quenched GCr15.

[0062] Test Example 2

[0063] The microhardness of the coating obtained in the embodiment was measured using a MH-500D microhardness tester, where the measuring load was 25 g and the holding time was 10 s. The test results are as follows:

[0064] The microhardness of the coating obtained in Example 1 is 1114.6HV, while the hardness of GCr15 after quenching is HRC60, which is converted into a microhardness of 666HV, and the microhardness is 67% higher than that of the quenched GCr15;

[0065] The microhardness of the coating obtained in Example 2 is 1115 HV, while the hardness of GCr15 after quenching is HRC60, which is converted into a microhardness of 666 HV. The microhardness is 67% higher than that of the quenched GCr15.

[0066] Test Example 3

[0067] The surface roughness of the coating was measured using a HUD280+ surface roughness meter. The surface roughness Ra of the coating obtained in Example 1 was 1.2 μm, and the surface roughness Ra of the coating obtained in Example 2 was 1.6 μm.

[0068] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An electrode for electrospark deposition, characterized in that: The electrode for electrospark deposition comprises the following components in terms of mass percentage: 35.0-45.0% TiN, 35.0-40.0% TiC, 5.0-10.0% Mo, 5.0-10.0% Co, 5.0-10.0% Ni and 0.01-1% rare earth elements.

2. The electrode for electrospark deposition according to claim 1, characterized in that: The rare earth element includes one or more of Y, La, Sc, Ce, Pr and Nd.

3. The electrode for electrospark deposition according to claim 1 or 2, characterized in that: The electrode for electrospark deposition consists of a substrate and a hard phase, wherein the substrate consists of Co, Ni, Mo and rare earth elements, and the hard phase consists of TiN and TiC.

4. The electrode for electrospark deposition according to claim 3, characterized in that: The length of the electrode for electrospark deposition is 100-120 mm, the width is 3-7 mm, and the thickness is 1-2.5 mm.

5. Use of the electrode for electrospark deposition according to any one of claims 1 to 4 in the preparation of wear-resistant coatings.

6. A method for preparing a wear-resistant coating, characterized in that: The following steps are involved: The wear-resistant coating is obtained by using the electrode for electrospark deposition as claimed in any one of claims 1 to 4 as a working electrode and depositing on the surface of a substrate by ultrasonic electrospark deposition.

7. The preparation method according to claim 6, characterized in that: The condition parameters of the ultrasonic electric spark deposition include: voltage of 60-110V, vibration frequency of 20000Hz, amplitude of 40μm, and discharge capacitance of 10-30μF.

8. The wear-resistant coating prepared by the preparation method according to claim 6 or 7, characterized in that: The wear-resistant coating consists of a matrix and a hard phase, wherein the matrix consists of Co, Ni, Mo and rare earth elements, and the hard phase consists of TiN and TiC.

9. The wear-resistant coating according to claim 8, characterized in that: The wear-resistant coating has a width of 3 to 7 mm and a thickness of 10 to 15 μm; The microhardness of the wear-resistant coating is 1000-1200 HV, and the surface roughness Ra is 1.0-2.0 μm.

10. Use of the wear-resistant coating according to claim 8 or 9 in a wheel rim mould.

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