Laser cladding powder for tip surface of sand collecting bucket of sand removing vehicle

Abstract

The application relates to a laser cladding powder for a sand-collecting bucket spade tip surface of a sand-collecting vehicle, and raw materials are composed of the following components in percentage by weight: Ti: 42.7%, Al: 7.5%, Cu: 3.0%, C: 0.03%, B: 0.1%, N: 0.1, and the balance is Zr. The Zr-based powder component of the application basically guarantees the original component proportion of the powder, the thermal expansion coefficient of the cladding layer formed by the cladding powder is increased to close to 45 steel matrix, meanwhile, the interface bonding property of the cladding layer and the matrix is improved, and the powder has good cladding effect. Due to the undercooling effect of the Cu element component and the heterogeneous nucleation effect of the B element, the cladding layer structure forms fine solidification structure, and nano-hard coherent compounds (TiZr)3Al and non-coherent compounds TiC and TiN are formed, so that the hardness and wear resistance of the material surface are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of cladding materials technology. Background Technology

[0002] The use of sand removal vehicles has effectively solved the problem of severe sand accumulation on railway tracks in Northwest my country. However, the tips of the sand collection buckets on these vehicles are prone to wear during operation, significantly reducing their service life. Therefore, improving the surface hardness and wear resistance of the materials used for the tips of the sand collection buckets on sand removal vehicles has become a current research focus.

[0003] Surface laser cladding technology is an effective means to improve the surface hardness and wear resistance of parts. By controlling the cladding material and microstructure, the surface properties of parts can be optimized. The performance of surface laser cladding is affected by many factors, with the cladding material being one of the most important. To obtain a good, crack-free cladding layer, the cladding material needs to have excellent comprehensive mechanical properties, and the cladding material and the substrate need to have similar coefficients of thermal expansion and compatibility.

[0004] Currently, most existing cladding powders are pre-mixed general-purpose commercial powders, but there are no special laser cladding powder materials for the metal tip of the sand collection bucket of sand removal vehicles. Summary of the Invention

[0005] The purpose of this invention is to provide a laser cladding powder for the surface of the sand collection bucket tip of a sand removal vehicle. This invention uses a Zr-based powder composition. The cladding layer formed by the powder essentially maintains the original component ratio of the powder. Cu and Al elements increase the thermal expansion coefficient of the cladding layer to near that of a 45 steel substrate, while simultaneously improving the interfacial bonding between the cladding layer and the substrate, resulting in excellent cladding performance. Due to the supercooling effect of Cu and the heterogeneous nucleation effect of Bo, the cladding layer microstructure forms a fine solidified structure, simultaneously forming nano-hard coherent compounds (TiZr)3Al and incoherent compounds TiC and TiN, effectively improving the surface hardness and wear resistance of the material.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The laser-clad powder on the surface of the sand collection bucket tip of the sand truck has the following composition by weight percentage: Ti: 42.7%, Al: 7.5%, Cu: 3.0%, C: 0.03%, B: 0.1%, N: 0.1%, with the balance being Zr.

[0007] The powder is prepared by mixing the various substances evenly according to the formula, and the average particle size of the powder is 80-150μm.

[0008] The tip of the sand-collecting bucket of the sand removal truck is made of 45 steel.

[0009] The powder is suitable for laser cladding, and is suitable for laser cladding of 45 steel substrate.

[0010] The powder composition design principle of this invention is as follows: Ti (42.7%) and Zr elements are dissolved in solid solution to improve strength. According to the binary and ternary phase diagrams of Zr, Ti and Al, the addition of Ti to more than 40% can promote the formation of (TiZr)3Al coherent compounds, which can improve hardness and wear resistance. However, the addition of Ti to more than 43% will produce other brittle compounds that significantly reduce toughness.

[0011] Adding more than 7% Al (7.5%) will form a (TiZr)3Al coherent compound, improving hardness and wear resistance. However, adding more than 8% will significantly reduce toughness. At the same time, Al can increase the coefficient of thermal expansion, giving the alloy a coefficient of thermal expansion similar to that of 45 steel for shovel tips, thus preventing the formation of hot cracks during cladding.

[0012] Cu (3%) can refine the microstructure through supercooling during solidification, and also improves the coefficient of thermal expansion and the bonding between the cladding layer and the substrate.

[0013] C (0.03%) and N (0.1%) elements can form a small amount of fine hard precipitates, which can improve hardness and wear resistance.

[0014] B (0.1%) can effectively refine the cladding layer structure through heterogeneous nucleation.

[0015] Zr provides high strength and toughness, thermal stability, and resistance to abrasion, fatigue, and stress corrosion cracking in the working environment.

[0016] The beneficial effects of adopting the above technical solution are: The Zr-based powder composition of this invention maintains the original component ratio of the powder in the cladding layer formed by the cladding powder. Cu and Al elements increase the thermal expansion coefficient of the cladding layer to near that of a 45 steel substrate, while also improving the interfacial bonding between the cladding layer and the substrate, resulting in excellent cladding performance. Due to the supercooling effect of Cu and the heterogeneous nucleation of B, the cladding layer microstructure forms a fine solidified structure, simultaneously forming nano-hard coherent compounds (TiZr)3Al and incoherent compounds TiC and TiN, effectively enhancing the surface hardness and wear resistance of the material. Attached Figure Description

[0017] Figure 1 This is the physical object prepared in Example 1 of the present invention.

[0018] Figure 2 This is a SEM image of the cladding layer structure prepared in Example 1 of the present invention.

[0019] Figure 3 This is a TEM image of the cladding layer structure prepared in Example 1 of the present invention.

[0020] Figure 4 The friction coefficient and morphology of the cladding layer and the substrate prepared in Example 1 of this invention are shown. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the following examples and comparative examples, the substrate is made of 45 steel with a diameter of 120 mm, a thickness of 15 mm, and a cladding layer thickness of 1 mm.

[0023] The powder weight percentage composition of each embodiment and comparative example is shown in Table 1 below: Table 1

[0024] The powder is prepared by mixing the various substances evenly according to the formula, and the average particle size of the powder is 80-150μm.

[0025] Before the cladding operation in the above embodiments and comparative examples, the substrate was pretreated by ultrasonic cleaning with acetone and drying with a blower. After drying, the mixed slurry was evenly coated onto the substrate surface and dried in an 80°C oven for 2-3 hours.

[0026] The above embodiments and comparative examples use vacuum chamber laser cladding. The cladding process parameters are: laser power 1200W, scanning speed 5mm / s, turntable voltage 9Vf, overlap rate 35%, and lifting amount 0.45mm.

[0027] The performance of the prepared workpieces was tested, and the test results are shown in Table 2 below: Table 2

[0028] As can be seen from the data in Table 2, the hardness and wear resistance of Example 1 were significantly improved.

[0029] Analysis of the microstructure of the cladding layer using scanning electron microscopy and transmission electron microscopy revealed that the microstructure of the cladding layer in Example 1 consisted of fine dendrites, and also formed nano-hard compounds (TiZr)3Al and incoherent compounds TiC and TiN. The combination of various factors led to a significant improvement in hardness and wear resistance.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A laser cladding powder for sand truck hopper blade tip surface, characterized in that: The raw material is composed of the following components in percentage by weight: Ti: 42.7%, Al: 7.5%, Cu: 3.0%, C: 0.03%, B: 0.1%, N: 0.1%, and the balance of Zr. ​ 2. The laser cladded powder for the sander hopper blade tip surface of claim 1, wherein: The sand-collecting bucket tip of the sand-collecting vehicle is made of 45 steel.

3. The laser cladded powder for the tip surface of the sander hopper blade of the sand removal vehicle according to claim 1 or 2, characterized in that: The powder is suitable for laser cladding.

4. The laser cladded powder for the tip surface of the sander hopper blade of the sand removal vehicle according to claim 1 or 2, characterized in that: The average particle size of the powder is 80-150 microns.

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