A laser cladding surface strengthening method for improving the wear resistance of pick teeth

Abstract

The present invention belongs to the field of surface engineering technology, and specifically relates to a laser cladding surface strengthening method for improving the wear resistance of picks. In order to solve the problem of poor hardness and wear resistance of existing picks due to insufficient surface strengthening, the present invention uses laser cladding technology to prepare a multi-component composite metal ceramic cladding layer on the outer surface of the pick, and the specific steps are: clean the pick and put it into a tooling; use a three-dimensional powder mixer to mix the cladding powder according to proportion; use a laser cladding device composed of a manipulator and a turntable to clad the wear-resistant layer on the conical surface of the pick, and send the mixed powder to the molten pool for melting through a powder feeder, and finally form a multi-component composite metal ceramic cladding layer on the outer surface of the pick. By optimizing the cladding process and cladding materials, the sedimentation, decarburization and decomposition of WC in the cladding process are significantly slowed down, and the lack of reinforcing phase at the top of the cladding layer is compensated by low-density TiC and diamond micropowder, so as to prepare a dense and defect-free wear-resistant cladding layer with high wear resistance and extended the service life of the pick.

Description

Technical Field

[0001] The invention belongs to the technical field of surface engineering, and in particular relates to a laser cladding surface strengthening method for improving the wear resistance of a pick. Background Art

[0002] Coal is my country's basic energy and important industrial raw material, providing a reliable energy guarantee for the national economy and social development. With the continuous advancement of the "dual carbon target", coal will continue to play an important supporting role in the future transformation of the energy structure. my country's coal is mainly mined underground, and the number of coal mining equipment required each year is astonishing. As one of the vulnerable parts in coal mining machinery such as coal mining and tunneling, the pick is not only subjected to shear stress, compressive stress and impact load during the coal mining process, but also in the harsh environment underground for a long time, prone to partial wear, chipping, tooth fracture and tooth stripping. Statistics show that 400-1300 picks are needed to mine 10,000 tons of coal, and the output value of the pick is calculated based on the annual coal mining volume. 16-52 billion yuan. Therefore, it is urgent to increase the research and development of pick technology, improve the wear resistance and impact resistance of the pick, and extend the service life of the pick.

[0003] In response to the wear failure of picks, surface engineering technologies such as plasma cladding, surfacing, and thermal spraying are used to prepare wear-resistant coatings on the surface of picks, which effectively improves the service performance of picks (patent CN 113586050 A, patent CN 113774377 A, etc.). However, the relevant surface strengthening technology only forms a mechanical bond with the substrate, and there are problems such as low bonding strength and expansion of the heat-affected zone of the substrate due to high heat input, which restricts the further improvement of the performance of the picks. In recent years, the rapid rise and development of laser cladding technology has provided a new way to strengthen picks. Compared with thermal spraying technology and surfacing technology, laser cladding has many advantages such as metallurgical bonding between the substrate and the cladding layer, small heat-affected zone, excellent performance of the cladding layer, and easy further processing of the repaired parts, providing a new strengthening method for improving the quality of picks. Summary of the invention

[0004] The invention aims to solve the problem that the existing pick surface is insufficiently strengthened, resulting in poor hardness and wear resistance of the pick surface, and provides a laser cladding surface strengthening method for improving the wear resistance of the pick, so as to improve the wear resistance of the pick and extend the service life.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a laser cladding surface strengthening method for improving the wear resistance of a pick, characterized in that a multi-component composite metal-ceramic cladding layer is prepared on the outer surface of the pick by using laser cladding technology.

[0006] The specific steps include:

[0007] S1: Clean the surface of the pick substrate and install it into the tooling;

[0008] S2: Use a three-dimensional powder mixer to mix the cladding powder according to the proportion;

[0009] S3: A laser cladding device with a manipulator and a turntable is used to clad the wear-resistant layer on the conical surface of the pick. The molten mixed cladding powder is sent to the molten pool for melting through a powder feeder, and finally a multi-component composite metal ceramic cladding layer is formed on the outer surface of the pick.

[0010] Further, the pick is preferably a pick-shaped pick.

[0011] Furthermore, the mixing time of the powder mixer in step S2 is 30-60 minutes.

[0012] Furthermore, the metal ceramic comprises the following raw materials in parts by weight: 35-65 parts of nickel-based alloy powder (Ni-B-Si), 30-60 parts of WC micropowder, 5-20 parts of TiC micropowder and 2-10 parts of diamond micropowder.

[0013] Furthermore, in step S3, the laser cladding process is as follows: cladding power 2-4KW, powder feeding amount 40-80g / min, overlap rate 40-60%, pick rotation speed 5-10rmp / min.

[0014] Furthermore, the particle sizes of the metal ceramic raw materials are: nickel-based alloy powder (Ni-B-Si) 40-100 μm, WC powder 100-250 μm, TiC 2-10 μm and diamond powder 30-50 μm.

[0015] Furthermore, the diamond powder is surface treated by salt bath tungsten infiltration.

[0016] Compared with the prior art, the advantages of the present invention are:

[0017] 1) The present invention uses laser cladding technology to prepare a multi-component composite metal ceramic cladding layer on the surface of the pick, thereby overcoming the problem of overheating of the substrate caused by the plasma cladding process.

[0018] 2) The present invention utilizes a laser cladding device with a manipulator and a turntable combination to achieve cladding of a wear-resistant layer on the conical surface of the pick.

[0019] 3) The present invention optimizes the multi-component cladding powder and utilizes the combination of WC, TiC and diamond powder, which not only significantly slows down the sedimentation of WC during the cladding process, but also compensates for the lack of the reinforcing phase at the top of the cladding layer through the low-density TiC and diamond powder.

[0020] 4) The present invention improves the wettability of diamond micropowder and nickel substrate through salt bath tungsten infiltration surface treatment.

[0021] 5) The present invention not only slows down the decarburization and decomposition of WC, but also prepares a dense, defect-free, wear-resistant cladding layer by optimizing the cladding process and cladding materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the surface strengthening of the pick surface by laser cladding according to the present invention;

[0023] Figure 2 This is the microstructure diagram of the salt bath chromized diamond powder of Example 1;

[0024] Figure 3 This is a microstructure diagram of the laser cladding metal ceramic layer on the surface of the pick in Example 1;

[0025] Figure 4 This is the microstructure diagram of the laser cladding metal ceramic layer on the surface of the pick in Comparative Example 1;

[0026] Figure 5 The comparison results of the hardness of the laser cladding metal ceramic layer on the surface of the pick of the present invention and the existing pick;

[0027] Figure 6 The results are a comparison of the wear resistance of the laser-clad metal ceramic layer on the surface of the pick of the present invention and that of the existing pick.

[0028] Among them: 1-pick-shaped pick, 2-pick tooling, 3-laser cladding controller, 4-manipulator controller, 5-high-speed laser cladding head, 6-manipulator, 7-laser cladding powder feeder. DETAILED DESCRIPTION

[0029] In order to make the technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] The present invention uses laser cladding technology to prepare a multi-component composite metal ceramic cladding layer on the surface of the pick. The high-energy beam laser cladding technology overcomes the problem of substrate overheating caused by the plasma cladding process; the cladding of the wear-resistant layer on the conical surface of the pick is achieved by combining a laser cladding device with a manipulator and a turntable; and the performance of the cladding layer is improved by combining a suitable metal phase and a ceramic reinforcement phase. Therefore, by using laser cladding technology, a high-performance pick wear-resistant cladding layer can be prepared by combining different ceramic phases and optimizing the cladding process, thereby extending the service life of the pick.

[0031] Example 1

[0032] A laser cladding surface strengthening method for improving the wear resistance of a pick, specifically: the pick is preferably a pick-shaped pick, and the wear-resistant layer cladding of the conical surface of the pick is achieved by using a laser cladding device with a manipulator and a turntable combination; through the optimization of the multi-component cladding powder, a multi-component composite metal ceramic cladding layer is prepared on the surface of the pick using laser cladding technology.

[0033] The specific steps include:

[0034] S1: Clean the surface of the pick substrate and install it into the tooling;

[0035] S2: Use a three-dimensional powder mixer to mix the cladding powder according to the proportion, and the mixing time is 30 minutes;

[0036] The composition of the cladding powder is: 50 parts of WC micropowder, 10 parts of TiC micropowder, 5 parts of diamond micropowder and 35 parts of nickel-based alloy powder (Ni-B-Si).

[0037] The particle sizes of the cladding powders are: nickel-based alloy powder (Ni-B-Si) 40 μm, WC powder 100 μm, TiC 2 μm and diamond powder 30 μm.

[0038] The diamond powder described in S2 is subjected to salt bath tungsten infiltration surface treatment. The specific process is: select a KCl / NaCl high temperature mixed salt bath system for tungsten infiltration treatment, the ratio of tungsten powder to diamond powder is 2:1, the infiltration process is 1000℃, and the temperature is kept for 4h. After the salt bath treatment, the salt bath diamond powder is separated by acid washing and boiling, and then dried in a vacuum oven at 80℃ for 240min. Its microscopic morphology is as follows: Figure 3 shown.

[0039] S3: A laser cladding device with a manipulator and a turntable is used to clad the wear-resistant layer on the conical surface of the pick. The mixed cladding powder is sent to the molten pool for melting through a powder feeder. The laser cladding process is: cladding power 3KW, powder feeding amount 50g / min, overlap rate 50%, pick rotation speed 5rmp / min, and finally a multi-component composite metal ceramic cladding layer is formed on the outer surface of the pick. The schematic diagram of the laser cladding process is shown in the figure. Figure 1 As shown in the figure, the specific cladding process of the pick is as follows: in order to meet the surface cladding of the pick-shaped pick 1, it is necessary to use the tooling 2 to adjust the surface of the pick to be clad to a horizontal position. Then, the laser cladding equipment controller 3, the manipulator controller 4 and the powder feeder 7 are turned on to prepare for cladding. Then, the high-speed cladding equipment is turned on, and the moving speed of the cladding head 5 is controlled by the manipulator 6 to achieve uniform cladding of the wear-resistant layer on the surface of the pick. The microscopic morphology of the prepared multi-component composite metal ceramic cladding layer is shown in FIG. Figure 2 shown.

[0040] Through analysis, the hardness of the wear-resistant cladding layer on the cone surface of the pick prepared by laser cladding technology is as high as 1200HV ( Figure 5 ), which is significantly higher than the hardness of the cladding layer prepared by the commercially available pick and the comparative example.

[0041] Furthermore, the wear weight loss of the wear-resistant cladding layer on the conical surface of the pick prepared by the laser cladding technology is as low as 4.5 mg / min ( Figure 6 ), which is significantly better than the hardness of the cladding layer prepared by the commercially available pick and the comparative example.

[0042] Example 2

[0043] A laser cladding surface strengthening method for improving the wear resistance of a pick, specifically: the pick is preferably a pick-shaped pick, and the wear-resistant layer cladding of the conical surface of the pick is achieved by using a laser cladding device with a manipulator and a turntable combination; through the optimization of the multi-component cladding powder, a multi-component composite metal ceramic cladding layer is prepared on the surface of the pick using laser cladding technology.

[0044] The specific steps include:

[0045] S1: Clean the surface of the pick substrate and install it into the tooling;

[0046] S2: Use a three-dimensional powder mixer to mix the cladding powder according to the proportion, and the mixing time is 60 minutes;

[0047] The composition of the cladding powder is: 50 parts of WC, 10 parts of TiC, 2 parts of diamond and 38 parts of nickel-based alloy (Ni-B-Si).

[0048] The particle sizes of the cladding powders are: nickel-based alloy powder (Ni-B-Si) 100 μm, WC powder 250 μm, TiC 10 μm and diamond powder 50 μm.

[0049] The diamond powder is subjected to a surface treatment of salt bath tungsten infiltration, and the specific process is: a KCl / NaCl high temperature mixed salt bath system is selected for tungsten infiltration, the ratio of tungsten powder to diamond powder is 4:1, the melt infiltration process is 1000°C, and the heat preservation is 8h. After the salt bath treatment, the salt bath diamond powder is separated by acid washing and boiling, and a vacuum oven is used for drying at 80°C for 240min.

[0050] S3: A laser cladding device with a manipulator and a turntable is used to clad the wear-resistant layer on the conical surface of the pick. The molten mixed cladding powder is sent to the molten pool for melting through a powder feeder. The laser cladding process is: cladding power 3KW, powder feeding amount 50g / min, overlap rate 50%, pick rotation speed 5rmp / min, and finally a multi-component composite metal ceramic cladding layer is formed on the outer surface of the pick.

[0051] Example 3

[0052] A laser cladding surface strengthening method for improving the wear resistance of a pick, specifically: the pick is preferably a pick-shaped pick, and the wear-resistant layer cladding of the conical surface of the pick is achieved by using a laser cladding device with a manipulator and a turntable combination; through the optimization of the multi-component cladding powder, a multi-component composite metal ceramic cladding layer is prepared on the surface of the pick using laser cladding technology.

[0053] The specific steps include:

[0054] S1: Clean the surface of the pick substrate and install it into the tooling;

[0055] S2: Use a three-dimensional powder mixer to mix the cladding powder according to the proportion, and the mixing time is 30 minutes;

[0056] The composition of the cladding powder is: 50 parts of WC, 5 parts of TiC, 10 parts of diamond and 35 parts of nickel-based alloy (Ni-B-Si).

[0057] The particle sizes of the cladding powders are: nickel-based alloy powder (Ni-B-Si) 50 μm, WC powder 150 μm, TiC 8 μm and diamond powder 40 μm.

[0058] The diamond powder is treated with salt bath tungsten infiltration surface. The specific process is: KCl / NaCl high temperature mixed salt bath system is used for tungsten infiltration treatment, the ratio of tungsten powder to diamond powder is 2:1, the infiltration process is 1000℃, and the temperature is kept for 4h. After the salt bath treatment, the salt bath diamond powder is separated by acid washing and boiling, and the vacuum oven is used for drying at 80℃ for 240min.

[0059] S3: A laser cladding device with a manipulator and a turntable is used to clad the wear-resistant layer on the conical surface of the pick. The mixed cladding powder is sent to the molten pool for melting through a powder feeder. The laser cladding process is: cladding power 3KW, powder feeding amount 50g / min, overlap rate 50%, pick rotation speed 5rmp / min. Finally, a multi-component composite metal ceramic cladding layer is formed on the outer surface of the pick.

[0060] Comparative Example 1

[0061] A laser cladding surface strengthening method for improving the wear resistance of a pick, specifically: the pick is preferably a pick-shaped pick, and the wear-resistant layer cladding of the conical surface of the pick is achieved by using a laser cladding device with a manipulator and a turntable combination; through the optimization of the multi-component cladding powder, a multi-component composite metal ceramic cladding layer is prepared on the surface of the pick using laser cladding technology.

[0062] The specific steps include:

[0063] S1: Clean the surface of the pick substrate and install it into the tooling;

[0064] S2: Use a three-dimensional powder mixer to mix the cladding powder according to the proportion, and the mixing time is 30 minutes;

[0065] The composition of the cladding powder is: 50 parts of WC and 50 parts of nickel-based alloy (Ni-B-Si).

[0066] The particle sizes of the cladding powders described in S2 are: 50 μm for nickel-based alloy powder (Ni-B-Si) and 120 μm for WC powder.

[0067] S3: A laser cladding device with a manipulator and a turntable is used to clad the wear-resistant layer on the conical surface of the pick. The mixed cladding powder is sent to the molten pool for melting through a powder feeder. The laser cladding process is: cladding power 3KW, powder feeding amount 50g / min, overlap rate 50%, pick rotation speed 5rmp / min, and finally a multi-component composite metal ceramic cladding layer is formed on the outer surface of the pick. The micromorphology of the prepared cladding layer is as follows Figure 4 shown.

[0068] The first embodiment of the present invention is the best embodiment. By optimizing the powder ratio of the laser cladding powder and using the powder combination of WC, TiC and diamond powder, the sedimentation of WC during the cladding process is significantly slowed down, and the lack of the reinforcing phase at the top of the cladding layer is compensated by the low-density TiC and diamond powder, and the hardness of the cladding layer is improved; by optimizing the cladding process, the decarburization and decomposition of WC are slowed down, and a dense, defect-free, wear-resistant cladding layer is prepared. Compared with the current picks, the laser cladding wear-resistant layer and pick sample analysis of the present invention show that the hardness of the laser cladding layer on the pick surface reaches 1350HV, which is nearly 50% higher than the single WC reinforcing phase cladding layer of Comparative Example 1, and about 60% higher than the current picks ( Figure 5 ); At the same time, the wear resistance of the composite cladding layer is about 43% higher than that of the single WC cladding layer and about 45% higher than that of the current pick ( Figure 6 ).

Claims

1. A laser cladding surface strengthening method for improving the wear resistance of a pick, characterized in that: The pick is a pick-shaped pick. The wear-resistant layer on the conical surface of the pick is clad by a laser cladding device with a manipulator and a turntable. The multi-component composite metal-ceramic cladding layer is prepared on the surface of the pick by optimizing the multi-component cladding powder using laser cladding technology. The specific steps include: S1: Clean the surface of the pick substrate and install it into the tooling; S2: The cladding powders are mixed in proportion using a three-dimensional powder mixer for 60 min; The composition of the cladding powder is: 50 parts of WC, 10 parts of TiC, 2 parts of diamond and 38 parts of nickel-based alloy; The particle sizes of cladding powders are: 100 μm for nickel-based alloy, 250 μm for WC powder, 10 μm for TiC and 50 μm for diamond powder. The nickel-based alloy is Ni-B-Si alloy. The diamond powder is subjected to a surface treatment of salt bath tungsten infiltration, and the specific process is: a KCl / NaCl high temperature mixed salt bath system is selected for tungsten infiltration treatment, the ratio of tungsten powder to diamond powder is 4:1, the tungsten infiltration treatment process temperature is 1000°C, and the temperature is kept for 8 hours; After the surface treatment of salt bath tungsten infiltration, the salt bath diamond powder was separated by acid washing and boiling, and then dried in a vacuum oven. The drying parameters were 80 ℃ and 240 min. S3: A laser cladding device with a manipulator and a turntable is used to clad the wear-resistant layer on the conical surface of the pick. The mixed cladding powder is sent to the molten pool for melting through a powder feeder. The laser cladding process is: cladding power 3kW, powder feeding amount 50g / min, overlap rate 50%, pick rotation speed 5rmp / min, and finally a multi-component composite metal ceramic cladding layer is formed on the outer surface of the pick.

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