Wear-resistant layer for guide shoe of coal mining machine and preparation method thereof

Abstract

The present invention discloses a wear-resistant layer for a guide shoe of a coal mining machine and a preparation method thereof. The wear-resistant layer is obtained by cladding ZG35CrMo on the guide shoe by an arc additive manufacturing method. The mass percentage of the wire used in the arc additive manufacturing process is as follows: C 3%-5%, Si 1.5%-2.6%, Mn 1.5%-2.5%, Cr26.0%-28.0%, Ni 0.1%-1.1%, W 3.0%-5.0%, and the remainder is Fe. The preparation method of the wear-resistant layer comprises the following steps: (1) weighing powders of each element except iron according to the mass proportion of each component element of the wire, using a powder mixing device to mix the above powders evenly, and using a wire forming machine to wrap the mixed powder with iron sheets to obtain wire used in additive manufacturing; (2) using MAG arc additive manufacturing technology to clad the surface of the preheated guide shoe, and cooling to obtain the wear-resistant layer. The above method can prepare a wear-resistant layer on the surface of the guide shoe before and after service without the need for a base layer. The prepared wear-resistant layer has high hardness, no cracks, good formability, and low wear rate, effectively improving the wear resistance of the guide shoe.

Description

Technical Field

[0001] The invention relates to the technical field of metal material surface modification, and in particular to a wear-resistant layer for a guide shoe of a coal mining machine and a preparation method thereof. Background Art

[0002] With the rapid development of my country's economy, the demand for coal has increased dramatically. Coal shearers are essential equipment for coal mining. Their efficient and reliable operation is crucial for ensuring coal mining efficiency, while the longevity and stability of their components determine their availability. Guide shoes are essential load-bearing components of coal shearers. Their primary function is to support the shearer's directional movement on the scraper conveyor, ensure the meshing of the shearer's gears with the pinion row, and withstand some of the shearer's gravity, cutting reaction forces, and lateral forces. They also guide the shearer's movement, ensuring its proper direction. During its service life, the guide shoe's fit with the pinion row is crucial. Improper fit can easily lead to interference and jamming between the rack and pinion row, resulting in broken teeth. Given the unique operating environment of coal shearers, they require high strength and toughness, as well as precise cross-sectional dimensions.

[0003] Furthermore, during actual coal mining operations, the inner surface of the guide shoe comes into contact with the pin row surface, allowing gangue to easily enter the gap between the guide shoe and the pin row. This makes the guide shoe susceptible to severe frictional wear and tear during use, and in severe cases, tooth breakage. Since shearers operate underground in coal mines, replacing the guide shoe is difficult, resulting in high labor intensity for maintenance workers, significantly reducing the shearer's operating rate and hindering the efficient and productive mining process. Due to the harsh underground conditions, replacing the guide shoe is time-consuming, labor-intensive, and costly. This further reduces mining efficiency during the replacement cycle, resulting in significant economic losses for coal mine production.

[0004] Therefore, developing an economical, fast and stable surface repair technology to achieve the initial modification and remanufacturing of guide shoes can significantly reduce production costs and obtain considerable economic benefits. Summary of the Invention

[0005] The technical problem addressed by this invention is to provide a wear-resistant layer for guide shoes of coal mining machines and a method for its preparation. First, the alloy composition of the wire used in the arc additive manufacturing process is designed based on the service environment and wear patterns of the guide shoes. Arc additive manufacturing is then used to apply the wear-resistant layer to the surface of the guide shoes before they are shipped or when they are severely worn. This preparation method is simple to operate, efficient, stable, and highly controllable. The high-strength second phase and matrix improve wear resistance, thereby extending the service life of the guide shoes.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A first aspect of the present invention provides a wear-resistant layer for a guide shoe of a coal mining machine, wherein the wear-resistant layer is prepared on the surface of the guide shoe by arc additive manufacturing; the additive wire used in the arc additive manufacturing contains the following elements, by mass percentage: C 3%-5%, Si 1.5%-2.6%, Mn 1.5%-2.5%, Cr 26.0%-28.0%, Ni0.1%-1.1%, W 3.0%-5.0%, and the balance is Fe.

[0008] The present invention adds carbon to the wear-resistant cladding layer to promote the formation of carbides in the steel matrix. If the carbon content is too low, it has poor compatibility with other elements in the steel, cannot form a large amount of carbides, and has poor wear resistance. If the carbon content is too high, the increase in carbon content will increase the hardenability, and cracks are easily formed during the cooling process, affecting the subsequent performance. The present invention uses thermodynamic software calculation and simulation, and through a large number of scientific experiments in the early stage, comprehensively considers the type and content of alloy elements in the wire and ensures that the alloy elements in the wire can form sufficient carbides (M 23 C6, M7C3, etc.), the C content is controlled at 3%-5%.

[0009] Silicon has a high binding energy with oxygen and is an indispensable deoxidizing element in the additive manufacturing process to suppress the formation of a large number of pores during the cooling process. At the same time, silicon has a strong solid solution strengthening effect on the steel matrix, which can significantly improve the strength and wear resistance of the matrix. Silicon tends to be enriched at the carbide crystallization front during solidification, thereby changing the morphology of the carbide. When selecting the silicon content, if the silicon content exceeds 3%, the plasticity and toughness of the wear-resistant layer will decrease significantly, and obvious cracks will appear. Therefore, the silicon content in the wire is controlled at 1.5%-2.6%, and more preferably 1.5% to 2.0%.

[0010] Manganese can form an infinite solid solution with iron, increasing the hardness and strength of the matrix. Manganese is also an austenite-stabilizing element and expands the austenite phase. During the solidification process of steel, it can promote the formation of a small amount of metastable austenite elements, alleviating the formation of cracks during solidification. Metastable austenite can also transform into martensite during friction and wear, improving wear resistance. In terms of manganese content, when the manganese content is less than 3%, it can increase high-temperature strength and toughness. Manganese is an economical and inexpensive element, and its content can be increased as much as possible. The manganese content in the above-mentioned wire is preferably 1.5%-2.5%.

[0011] Chromium can increase the hardness of the surface cladding metal, and has a good affinity with carbon, and can preferentially form stable carbides. These carbides have excellent wear resistance and can improve the wear resistance and corrosion resistance of the cladding layer. Volume fraction of carbides It is closely related to the carbon and chromium content and can be calculated as follows:

[0012]

[0013] Dispersing fine carbides in the carbide distribution improves wear resistance. However, excessive Cr content reduces plasticity, which is detrimental to thermal fatigue performance. Most wear-resistant steels have a carbon-chromium ratio of approximately 4-8. In this application, considering factors such as economic cost, carbide content, and distribution, and through extensive calculations and experimental exploration, the chromium content in the wire is preferably 26% to 28%.

[0014] Furthermore, preferably, in the additive wire, w(C)=0.11w(Cr)+0.3%, where w(C) is the mass percentage of carbon in the additive wire, and w(Cr) is the mass percentage of chromium in the additive wire.

[0015] In the process of forming carbides, the mass percentage of carbon and chromium was initially selected to be approximately 0.1, taking into account the relative content of each element in M7C3 carbides. At the same time, taking into account the order of combining carbon with the elements in the wire, and ensuring that chromium can be fully precipitated to form a large number of dispersed and evenly distributed carbides, the ratio of carbon to chromium was selected to be approximately 0.11. During the solidification process, some carbon will enter the lattice matrix to form an interstitial solid solution. Through preliminary scientific research, it was found that its percentage is approximately 0.3%. Therefore, when the content ratio of carbon and chromium in the wire satisfies w(C) = 0.11w(Cr) + 0.3%, M7C3 has the best effect in promoting wear resistance.

[0016] During the arc wire additive manufacturing process, hot cracking is highly likely to occur due to rapid cooling rates, high carbon content, and the strong kinetic driving force for second-phase formation. Nickel, insoluble in carbides during steel solidification, dissolves completely into the matrix, improving its hardenability. Furthermore, nickel promotes austenite stability, while retained austenite prevents further crack propagation and prevents extensive cracking in the cladding layer. Based on the appropriate combination of manganese and previous research on retained austenite stability, the nickel content is set at 0.1%-1.1%.

[0017] Tungsten and carbon have a strong bond, forming carbides like WC, which are extremely hard. During friction and wear, the high hardness of WC acts as a support point, preventing further wear. Considering the carbon and chromium content, the preferred tungsten content in the wire is 3.0%-5.0%.

[0018] Furthermore, in the additive wire, w(Cr)=w(W)+23%, where w(Cr) is the mass percentage of chromium in the additive wire, and w(W) is the mass percentage of tungsten in the additive wire.

[0019] In the wire used to prepare the wear-resistant layer, tungsten and chromium must be added synergistically. Simply adding one element alone will not achieve optimal wear resistance, and the amounts of both elements must be controlled in tandem. Considering the formation priorities of carbon, chromium, and tungsten, optimal wear resistance is achieved only when a significant amount of chromium-containing carbides is formed. Preliminary scientific experiments have shown that excellent wear resistance is only achieved when the difference between the chromium and tungsten content exceeds a critical 23%.

[0020] Furthermore, the guide shoe is made of ZG35CrMo.

[0021] Furthermore, the guide sliding shoe may be a guide sliding shoe before use, or a guide sliding shoe after severe friction and wear.

[0022] Furthermore, the arc additive manufacturing method is to use a melting active gas shielding arc as a heat source, and the shielding gas is a mixed gas of argon and carbon dioxide, and the mixing ratio thereof is 4:1.

[0023] Furthermore, the additively manufactured wear-resistant layer of the guide shoe has a structure of martensite.

[0024] Furthermore, a large amount of high-hardness carbides, such as (Fe, Cr)7C3 and WC, are formed in the additively manufactured wear-resistant layer of the guide shoe.

[0025] A second aspect of the present invention provides a method for preparing the wear-resistant layer according to the first aspect, comprising the following steps:

[0026] (1) Weighing carbon, silicon, manganese, chromium, nickel, and tungsten powders according to the mass ratio of each component element of the wire, using a powder mixing device to mix the above powders evenly, and using a wire forming machine to wrap the mixed powders with iron sheet to obtain a wire;

[0027] (2) The wire prepared in step (1) is used as a cladding material, and arc additive manufacturing is used to clad the surface of the guide shoe after preheating to obtain a wear-resistant layer.

[0028] Furthermore, in step (2), the pretreatment temperature is 231-249°C.

[0029] Furthermore, in step (2), the surface of the guide shoe does not need to be coated with a base layer or an intermediate layer, and the cladding can be performed directly on the surface after preheating treatment.

[0030] Furthermore, the process parameters of the arc additive manufacturing are: current 301-340A, 30-32V, and welding gun movement speed 0.8-1m / min.

[0031] Furthermore, the arc reciprocating method was used to perform additive manufacturing in 2-3 passes, and the inter-cladding layer temperature was 201-229°C.

[0032] Furthermore, the thickness of the wear-resistant cladding layer is 6 mm to 10 mm.

[0033] Furthermore, the preparation method also includes a post-processing step, specifically: machining the wear-resistant cladding layer prepared on the surface of the guide shoe to remove surface excess height and welding slag before use.

[0034] The beneficial effects of the present invention are:

[0035] 1. To improve the wear resistance of the guide shoe surface of a coal mining machine, the present invention proposes to prepare a wear-resistant cladding layer on the guide shoe surface. The wire material used in the prior art is primarily DG09, whose primary chemical components by mass percentage are: C 1.6-1.8, Cr 5.5-8.5, Mo <1.0, Mn <0.8, and Si 0.6-1.0. Due to its low carbon content, the microstructure is martensite, while also containing very small amounts of chromium-containing carbides. The chromium dissolves into the iron matrix, strengthening the structure and enhancing wear resistance primarily through the high-hardness martensite. The present invention, however, firstly designs a new alloy wire through theoretical calculations and extensive preliminary scientific experiments. By increasing the carbon and chromium content, combined with subsequent preheating and interlayer temperature control, this alters the precipitation kinetics and precipitation pathways, promoting the formation of a large number of dispersed, finely distributed chromium-containing carbides in the cladding layer. These carbides have a high hardness, effectively improving the wear resistance of the surface cladding layer. The new wire also contains a certain amount of tungsten, which prioritizes the formation of a certain amount of ultra-high-hardness tungsten carbide in the wear-resistant layer. The tungsten carbide and chromium-containing carbide work synergistically to improve the wear resistance of the cladding layer. Furthermore, by controlling the carbon, chromium, and tungsten content in the wire, the wear resistance of the cladding layer can be further optimized.

[0036] 2. The present invention utilizes the alloy wire prepared by the above-mentioned design to produce a cladding layer on the surface of the guide shoe through arc additive manufacturing. The guide shoe base material (ZG35CrMo, ZG35CrMoV, etc.) has a high carbon equivalent, and the cladding layer also has a high carbon equivalent. To better connect the base and the cladding layer, the traditional guide shoe additive manufacturing cladding process requires the use of a low-carbon material as a base layer (CN101608546A). In this application, despite the high carbon equivalent of the cladding layer, through alloy cost optimization and appropriate preheating and subsequent cooling control, additive manufacturing can be performed directly on the surface of the guide shoe without the need for a base layer, effectively improving the efficiency of additive manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a surface picture of the cladding layer prepared in Example 1;

[0038] Figure 2The morphology of the surface of the cladding layer prepared in Example 1 after wear;

[0039] Figure 3 The microscopic morphology of the surface of the cladding layer prepared in Example 1 after wear;

[0040] Figure 4 This is the microstructure of the cladding layer prepared in Example 1. DETAILED DESCRIPTION

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0043] Example 1

[0044] This embodiment relates to a method for improving the wear resistance of a guide shoe of a coal mining machine. The method mainly comprises forming a high-hardness wear-resistant layer on the surface of the guide shoe using arc additive manufacturing technology. The wire material used contains the following elements by mass percentage: C 3%, Si 1.6%, Mn 2%, Cr 27%, Ni 0.2%, W 4%, and the balance is Fe. The guide shoe is made of ZG35CrMo. The wear-resistant layer is prepared as follows:

[0045] (1) Weigh carbon, silicon, manganese, chromium, nickel, and tungsten powders according to the mass ratio of each element in the wire, mix the powders evenly using a powder mixing device, and use a wire forming machine to wrap the powders with iron sheets to form a wire with a diameter of 1.6 mm;

[0046] (2) The surface of the guide shoe is preheated with a flame at a preheating temperature of 235°C, and a MAG welder is used to perform additive manufacturing on the surface of the guide shoe; the process parameters are: current 305A, voltage 30V, speed 0.8m / min, shielding gas composition 80% Ar + 20% CO2, gas flow rate 15L / min, the arc motion trajectory during the additive manufacturing process is a broken line, and the process is completed in two passes, with an interlayer temperature of 210°C. A wear-resistant cladding layer can be obtained by the above method;

[0047] (3) Use a machine tool to process the wear-resistant cladding layer prepared on the surface of the guide shoe to remove the excess height.

[0048] The wear-resistant cladding layer prepared in this embodiment is as follows Figure 1 As shown in the figure, it can be seen that the prepared wear-resistant cladding layer has good surface formability and no obvious cracks are observed; the microstructure morphology is as follows Figure 4 As shown, it is martensite and dispersed carbides.

[0049] The friction and wear performance test of the wear-resistant layer prepared in this embodiment was carried out. A friction and wear testing machine was used to simulate the service wear test. The final wear rate was determined to be 0.16*10 -4 N -1 mm -1 The surface morphology of the wear-resistant layer after wear is as follows: Figure 2 As shown in Figure 2, the wear scar is narrow and no obvious wear debris is observed ( Figure 3 ), which also shows that the wear-resistant layer prepared by the present invention exhibits good wear resistance.

[0050] Example 2

[0051] This embodiment relates to a method for improving the wear resistance of the surface of a guide shoe of a coal mining machine. The method mainly involves forming a high-hardness wear-resistant layer on the surface of the guide shoe using arc additive manufacturing technology. The wire material used contains the following components by mass percentage: C 3.5%, Si 1.7%, Mn 2.1%, Cr 26.6%, Ni 0.3%, W 3.5%, and the balance is Fe. The material of the guide shoe is ZG35CrMo. The specific preparation process is as follows:

[0052] (1) Weigh carbon, silicon, manganese, chromium, nickel, and tungsten powders according to the mass ratio of each component of the wire, mix the powders evenly using a powder mixing device, and use a wire forming machine to wrap the powders with iron sheets to form a wire with a diameter of 1.6 mm;

[0053] (2) The surface of the guide shoe is preheated with a flame at a preheating temperature of 238°C, and a MAG welder is used to perform additive manufacturing on the surface of the guide shoe; the process parameters are: current 308A, voltage 30V, speed 0.9m / min, shielding gas composition 80% Ar + 20% CO2, gas flow rate 17L / min, the arc motion trajectory during the additive manufacturing process is a broken line, and the process is completed after 3 passes, and the interlayer temperature is 215°C. The wear-resistant cladding layer can be obtained by the above method;

[0054] (3) Use a machine tool to process the wear-resistant cladding layer prepared on the surface of the guide shoe to remove the excess height.

[0055] The friction and wear performance test of the wear-resistant layer prepared in this embodiment was carried out. A friction and wear testing machine was used to simulate the service wear test. The final wear rate was determined to be 0.28*10 -4 N-1 mm -1 .

[0056] Example 3

[0057] This embodiment relates to a method for improving the wear resistance of the surface of a guide shoe of a coal mining machine. The method mainly involves forming a high-hardness wear-resistant layer on the surface of the guide shoe using arc additive manufacturing technology. The wire material used contains the following components by weight: C 4.1%, Si 1.7%, Mn 2.3%, Cr 27%, Ni 0.3%, W 3.9%, and the balance is Fe. The guide shoe is made of ZG35CrMo. The specific preparation process is as follows:

[0058] (1) Weigh carbon, silicon, manganese, chromium, nickel, and tungsten powders according to the mass ratio of each component of the wire, mix the powders evenly using a powder mixing device, and use a wire forming machine to wrap the powders with iron sheets to form a wire with a diameter of 1.6 mm;

[0059] (2) The surface of the guide shoe is preheated with a flame at a preheating temperature of 240°C, and a MAG welder is used to perform additive manufacturing on the surface of the guide shoe; the process parameters are: current 315A, voltage 31V, speed 0.9m / min, shielding gas composition 80% Ar + 20% CO2, gas flow rate 16L / min, the arc motion trajectory during the additive manufacturing process is a broken line, and the process is completed after 3 passes, and the interlayer temperature is 219°C. A wear-resistant cladding layer can be obtained by the above method;

[0060] (3) Use a machine tool to process the wear-resistant cladding layer prepared on the surface of the guide shoe to remove the excess height.

[0061] The friction and wear performance test of the wear-resistant layer prepared in this embodiment was carried out. A friction and wear testing machine was used to simulate the service wear test. The final wear rate was determined to be 0.24*10 -4 N -1 mm -1 .

[0062] Example 4

[0063] This embodiment relates to a method for improving the surface wear resistance of a guide shoe of a coal mining machine. The method mainly involves forming a high-hardness wear-resistant layer on the surface of the guide shoe using arc additive manufacturing technology. The wire used contains the following components by mass percentage: C 4%, Si 2%, Mn 2.1%, Cr 27.1%, Ni 0.7%, W 4.1%, and the balance is Fe. The guide shoe is made of ZG35CrMo. The specific preparation process is as follows:

[0064] (1) Weigh carbon, silicon, manganese, chromium, nickel, and tungsten powders according to the mass ratio of each component of the wire, mix the powders evenly using a powder mixing device, and use a wire forming machine to wrap the powders with iron sheets to form a wire with a diameter of 1.6 mm;

[0065] (2) The surface of the guide shoe is preheated with a flame at a preheating temperature of 241°C, and a MAG welder is used to perform additive manufacturing on the surface of the guide shoe; the process parameters are: current 320A, voltage 31V, speed 1m / min, shielding gas composition 80% Ar + 20% CO2, gas flow rate 17L / min, the arc motion trajectory during the additive manufacturing process is a broken line, and the process is completed in two passes, with an interlayer temperature of 220°C. A wear-resistant cladding layer can be obtained by the above method;

[0066] (3) Use a machine tool to process the wear-resistant cladding layer prepared on the surface of the guide shoe to remove the excess height.

[0067] The friction and wear performance test of the wear-resistant layer prepared in this embodiment was carried out. A friction and wear testing machine was used to simulate the service wear test. The final wear rate was determined to be 0.22*10 -4 N -1 mm -1

[0068] Example 5

[0069] This embodiment relates to a method for improving the wear resistance of the surface of a guide shoe of a coal mining machine. The method mainly involves forming a high-hardness wear-resistant layer on the surface of the guide shoe using arc additive manufacturing technology. The wire material used contains the following components by mass percentage: C 3.3%, Si 2.0%, Mn 2.3%, Cr 27.6%, Ni 1%, W 4.6%, and the balance is Fe. The material of the guide shoe is ZG35CrMo. The specific preparation process is as follows:

[0070] (1) Weigh carbon, silicon, manganese, chromium, nickel, and tungsten powders according to the mass ratio of each component of the wire, mix the powders evenly using a powder mixing device, and use a wire forming machine to wrap the powders with iron sheets to form a wire with a diameter of 1.6 mm;

[0071] (2) The surface of the guide shoe is preheated with a flame at a preheating temperature of 243°C, and a MAG welder is used to perform additive manufacturing on the surface of the guide shoe; the process parameters are: current 335A, voltage 32V, speed 1m / min, shielding gas composition 80% Ar + 20% CO2, gas flow rate 18L / min, the arc motion trajectory during the additive manufacturing process is a broken line, and the process is completed after 3 passes, and the interlayer temperature is 225°C. The wear-resistant cladding layer can be obtained by the above method;

[0072] (3) Use a machine tool to process the wear-resistant cladding layer prepared on the surface of the guide shoe to remove the excess height.

[0073] The friction and wear performance test of the wear-resistant layer prepared in this embodiment was carried out. A friction and wear testing machine was used to simulate the service wear test. The final wear rate was determined to be 0.11*10 -4 N -1 mm -1 .

[0074] Comparative Example 1

[0075] This embodiment relates to a method for improving the surface wear resistance of a guide shoe of a coal mining machine. The method mainly involves forming a high-hardness wear-resistant layer on the surface of the guide shoe using arc additive manufacturing technology. The wire material used contains the following components by mass percentage: C 1%, Si 3%, Mn 1%, Cr 26%, Ni 0.3%, and the balance is Fe. The guide shoe is made of ZG35CrMo. The specific preparation process is as follows:

[0076] (1) Weigh carbon, silicon, manganese, chromium, nickel, and tungsten powders according to the mass ratio of each component of the wire, mix the powders evenly using a powder mixing device, and use a wire forming machine to wrap the powders with iron sheets to form a wire with a diameter of 1.6 mm;

[0077] (2) The surface of the guide shoe is preheated with a flame at a preheating temperature of 100°C, and a MAG welder is used to perform additive manufacturing on the surface of the guide shoe; the process parameters are: current 290A, voltage 28V, speed 1.2m / min, shielding gas composition 80% Ar + 20% CO2, gas flow rate 12L / min, the arc motion trajectory during the additive manufacturing process is a broken line, and the process is completed after 3 passes, and the interlayer temperature is 400°C. The wear-resistant cladding layer can be obtained by the above method;

[0078] (3) Use a machine tool to process the wear-resistant cladding layer prepared on the surface of the guide shoe to remove the excess height.

[0079] The friction and wear performance test of the wear-resistant layer prepared in this comparative example was carried out. A friction and wear testing machine was used to simulate the service wear test. The final wear rate was determined to be 0.64*10 -4 N -1 mm -1 .

[0080] Comparative Example 2

[0081] This embodiment relates to a method for improving the wear resistance of the surface of a guide shoe of a coal mining machine. The method mainly involves forming a high-hardness wear-resistant layer on the surface of the guide shoe using arc additive manufacturing technology. The wire used contains the following components by mass percentage: C 4%, Si 1.7%, Mn 5%, Cr 13%, Ni 0.3%, W 1%, and the balance is Fe. The material of the guide shoe is ZG35CrMo. The specific preparation process is as follows:

[0082] (1) Weigh carbon, silicon, manganese, chromium, nickel, and tungsten powders according to the mass ratio of each component of the wire, mix the powders evenly using a powder mixing device, and use a wire forming machine to wrap the powders with iron sheets to form a wire with a diameter of 1.6 mm;

[0083] (2) The surface of the guide shoe is preheated with a flame at a preheating temperature of 200°C, and a MAG welder is used to perform additive manufacturing on the surface of the guide shoe; the process parameters are: current 350A, voltage 35V, speed 0.7m / min, shielding gas composition 80% Ar + 20% CO2, gas flow rate 120L / min, the arc motion trajectory during the additive manufacturing process is a broken line, and the process is completed after 3 passes, and the interlayer temperature is 100°C. The wear-resistant cladding layer can be obtained by the above method;

[0084] (3) Use a machine tool to process the wear-resistant cladding layer prepared on the surface of the guide shoe to remove the excess height.

[0085] The friction and wear performance test of the wear-resistant layer prepared in this comparative example was carried out. A friction and wear testing machine was used to simulate the service wear test. The final wear rate was determined to be 0.72*10 -4 N -1 mm -1 .

[0086] Comparative Example 3

[0087] This embodiment relates to a method for improving the wear resistance of the surface of a guide shoe of a coal mining machine. The method mainly involves forming a high-hardness wear-resistant layer on the surface of the guide shoe using arc additive manufacturing technology. The wire material used contains the following components by mass percentage: C 5%, Si 3%, Mn 2.1%, Cr 26%, Ni 0.3%, and the balance is Fe. The material of the guide shoe is ZG35CrMo. The specific preparation process is as follows:

[0088] (1) Weigh carbon, silicon, manganese, chromium, nickel, and tungsten powders according to the mass ratio of each component of the wire, mix the powders evenly using a powder mixing device, and use a wire forming machine to wrap the powders with iron sheets to form a wire with a diameter of 1.6 mm;

[0089] (2) The surface of the guide shoe is preheated with a flame at a preheating temperature of 150°C, and a MAG welder is used to perform additive manufacturing on the surface of the guide shoe; the process parameters are: current 310A, voltage 30V, speed 1.2m / min, shielding gas composition 80% Ar + 20% CO2, gas flow rate 17L / min, the arc motion trajectory during the additive manufacturing process is a broken line, and the process is completed after 4 passes, and the interlayer temperature is 150°C. The wear-resistant cladding layer can be obtained by the above method;

[0090] (3) Use a machine tool to process the wear-resistant cladding layer prepared on the surface of the guide shoe to remove the excess height.

[0091] The friction and wear performance test of the wear-resistant layer prepared in this comparative example was carried out. A friction and wear testing machine was used to simulate the service wear test. The final wear rate was determined to be 0.8*10 -4 N -1 mm -1 .

[0092] Comparative Example 4

[0093] The difference between this comparative example and Example 1 is that this comparative example uses conventional DG09 welding wire to prepare the cladding layer on the surface of the unused guide shoe, and the other conditions are the same. The wear resistance of the wear-resistant cladding layer prepared in this comparative example was tested. A friction and wear tester was used to simulate the service wear test. The final wear rate was measured by the weight loss method to be 0.52*10 -4 N -1 mm -1 .

[0094] The comparative data of the wear resistance of the cladding layers prepared using different welding wires in the above embodiments and comparative examples are shown in Table 1 below:

[0095] Table 1 Wear rate of cladding layers prepared by different welding wires

[0096]

[0097]

[0098] It can be seen from the wear rate test data in Table 1 that the cladding layer prepared on the surface of the guide shoe by the arc additive manufacturing method using the alloy wire of the present invention has a significantly lower wear rate than the cladding layer prepared using conventional DG09, that is, the wear resistance is more than doubled; among them, the wear-resistant layers prepared in Examples 1 and 5 by linkedly controlling the carbon, chromium and tungsten contents in the wire have better wear resistance than those of other Examples and Comparative Examples.

[0099] Compared with Examples 1 to 5, the wire prepared in Comparative Example 1 does not contain tungsten, and has low contents of carbon and manganese. The wear resistance of the wear-resistant layer prepared therefrom is much lower than that of the wear-resistant layer prepared in the examples, and even slightly lower than that of the wear-resistant layer prepared by the DG09 welding wire. The wire prepared in Comparative Example 2 contains relatively small amounts of chromium and tungsten, but high contents of carbon and manganese. The wear rate of the wear-resistant layer prepared therefrom is slightly higher than that of Comparative Example 1. The composition of the wire in Comparative Example 3 does not contain tungsten, and the content of carbon is much higher than the required amount. The wear rate of the wear-resistant layer prepared therefrom is the highest under the same conditions.

[0100] The above-described embodiments are merely preferred embodiments for the purpose of fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are within the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

Claims

1. A wear-resistant layer for a guide shoe of a coal mining machine, characterized in that: The wear-resistant layer is prepared on the surface of the guide shoe by arc additive manufacturing; the additive wire used in the arc additive manufacturing contains the following elements by mass percentage: C 3%-5%, Si 1.5%-2.6%, Mn 1.5%-2.5%, Cr 26.0%-28.0%, Ni 0.1%-1.1%, W 3.0%-5.0%, and the balance is Fe; In the additive wire, w(C)=0.11w(Cr)+0.3%, where w(C) is the mass percentage of carbon in the additive wire, and w(Cr) is the mass percentage of chromium in the additive wire.

2. The wear-resistant layer for a guide shoe of a coal mining machine according to claim 1, characterized in that: The mass percentage of silicon in the additive filament is 1.5% to 2.0%.

3. The wear-resistant layer for a guide shoe of a coal mining machine according to claim 1, characterized in that: In the additive wire, w(Cr)=w(W)+23%, where w(Cr) is the mass percentage of chromium in the additive wire, and w(W) is the mass percentage of tungsten in the additive wire.

4. The wear-resistant layer for a guide shoe of a coal mining machine according to claim 1, characterized in that: The guide shoe is made of ZG35CrMo.

5. The wear-resistant layer for a guide shoe of a coal mining machine according to claim 1, characterized in that: The arc additive manufacturing method is to melt the active gas to shield the arc, and the shielding gas is a mixed gas of argon and carbon dioxide in a volume ratio of 4:

1.

6. The wear-resistant layer for a guide shoe of a coal mining machine according to claim 1, characterized in that: The matrix structure of the wear-resistant layer of the guide shoe is martensite.

7. A method for preparing the wear-resistant layer according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Weigh carbon, silicon, manganese, chromium, nickel, and tungsten powders according to the mass ratio of each component element of the wire, mix the above powders evenly using a powder mixing device, and use a wire forming machine to wrap the mixed powders with iron sheets to obtain wire; (2) The wire prepared in step (1) is clad on the surface of the guide shoe after preheating by using an arc additive manufacturing method to obtain a wear-resistant layer.

8. The preparation method according to claim 7, characterized in that In step (2), the temperature of the preheating treatment is 231-249°C.

9. The preparation method according to claim 7, characterized in that In step (2), the process parameters of the arc additive manufacturing are: current 301~340 A, voltage 30~32 V, and welding gun moving speed 0.8~1 m / min.

10. The preparation method according to claim 7, characterized in that Additive manufacturing is performed in 2 to 3 passes using an arc reciprocating method, with the temperature between cladding layers being 201 to 229°C. The thickness of the wear-resistant cladding layer is 6 to 10 mm, and the wear-resistant layer prepared on the surface of the guide shoe is machined to remove surface excess height and welding slag before use.

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