Process for preparing wear-resistant cladding layer containing tungsten carbide particles on 40Cr steel plane

Abstract

The medium-carbon low-alloy steel 40Cr is widely used in components such as gears, bearings, connecting rods and the like due to the fact that the medium-carbon low-alloy steel 40Cr has high strength, plasticity and toughness. However, the use of these workpieces mostly requires mutual contact of their surfaces. Therefore, the abrasion of the surface of the base material is unavoidable, and particularly, the abrasion of the base material is more serious in severe environments in the fields of petroleum and mines. Therefore, the invention provides a process for preparing the wear-resistant cladding layer containing the tungsten carbide particles on the 40Cr steel plane so as to improve the hardness and the wear resistance of the 40Cr steel plane. Compared with a traditional wear-resistant cladding layer preparation scheme, the wire and powder combined process is adopted in the research, so that the problem of insufficient particle content in a wire material process is solved, and the defects of poor cladding layer forming effect, low bonding strength between matrixes and the like in a single powder laying process are overcome. The powder comprises the following components: 90% of biphase eutectic tungsten carbide particles; 9% of nickel powder; the content of trace elements such as silicon iron is 1%, and the powder filling rate is about 40%. By optimizing parameters of a deposition process and a welding process, the hardness and the wear resistance of the surface of the 40Cr steel are obviously improved, and the service life of the 40Cr steel is prolonged.

Description

Technical Field

[0001] This invention relates to the field of wear-resistant cladding technology, specifically to a process for preparing a wear-resistant cladding layer containing tungsten carbide particles on a flat surface of 40Cr steel. Background Technology

[0002] In recent years, with the rapid development of my country's industrial technology, steel materials have been widely used. In particular, advanced technologies and equipment in fields such as aerospace, vehicle manufacturing, and oil extraction have placed higher demands on the service standards of steel. However, steel often faces failure issues during use. Medium-carbon low-alloy steel 40Cr, with its high strength, plasticity, and toughness, has been widely used in components such as gears, bearings, and connecting rods. However, these components mostly require surface contact. Therefore, wear on the substrate surface is unavoidable, especially in the harsh environments of the oil and mining industries, where wear is more severe. Therefore, before using 40Cr steel, appropriate surface strengthening treatment can be performed according to its actual application environment to improve its performance and extend its service life.

[0003] The preparation of particle-reinforced wear-resistant cladding is a commonly used surface strengthening method. By preparing a cladding layer containing high-hardness and wear-resistant particles on a substrate, the surface hardness and wear resistance of the material can be significantly improved. However, traditional particle-reinforced wear-resistant cladding processes have certain limitations. For example, in wire processing, the amount of hard particles added to the flux-cored wire is often limited, while pre-laying powder processes are constrained by poor cladding layer formation, low bonding strength with the substrate, and susceptibility to cracking. Therefore, it is necessary to design a particle-reinforced wear-resistant cladding process to address the shortcomings of the above two processes, so that the final cladding layer contains a large number of uniformly distributed hard particles to improve the surface hardness and wear resistance of 40Cr steel. Summary of the Invention

[0004] To address the shortcomings of current production technologies, this invention provides a process for preparing a wear-resistant cladding layer containing tungsten carbide particles on a flat surface of 40Cr steel. This includes the design of the composition of the flux-cored wire and pre-placed powder, and the exploration and optimization of processes such as deposition current, wire feed speed, and wire feed angle. This process is simple to operate and can be used in actual production. Using this process, a well-formed wear-resistant cladding layer with high bonding strength to the substrate can be prepared on a flat surface of 40Cr steel, significantly improving the hardness and wear resistance of the 40Cr steel surface. The overall hardness of the prepared wear-resistant cladding layer can reach over 630 HV1, and the wear loss volume is reduced to 0.33 μm. 3 The efficiency was increased to approximately 3 times and 45 times that of the substrate, respectively. The technical solution of the invention is as follows:

[0005] A process for preparing a wear-resistant cladding layer containing tungsten carbide particles on a flat surface of 40Cr steel includes the design of the composition of flux-cored wire and pre-placed powder, and the exploration and optimization of processes such as deposition current, wire feeding speed, and wire feeding angle.

[0006] The method includes the following steps:

[0007] (1) Preparation of substrate:

[0008] The 40Cr steel is processed into a size of 100mm×100mm×10mm using a cutting machine, and the 100mm×10mm flat surface is used for subsequent cladding.

[0009] (2) Composition design of flux-cored welding wire and pre-placed powder:

[0010] To improve the hardness and wear resistance of the substrate surface, the flux-cored welding wire and pre-placed powder are composed of irregularly shaped tungsten carbide particles of different sizes, as well as nickel powder and a mixture of trace elements such as ferrosilicon.

[0011] (3) Pre-powder spreading process:

[0012] This study uses a wire-powder combination method, which requires preparing a pre-coating layer containing tungsten carbide particles on the surface to be clad before the cladding work begins.

[0013] (4) Selection of welding process parameters:

[0014] This study uses TIG arc cladding technology with the following process parameters: 99.9% argon as the shielding gas, with a flow rate of 10 L / min; tungsten electrode tip diameter of 3.2 mm, approximately 6 mm from the substrate surface; DC welding; cladding current of 120-140 A; cladding speed of 0.05 m / min; and wire feed speed of 0.8-1.4 m / min.

[0015] (5) Optimization of welding process:

[0016] To improve the forming quality of the cladding layer and the distribution of tungsten carbide particles within it, a tungsten electrode oscillation process was incorporated into the cladding process. Furthermore, adjusting the distance between the tungsten electrode and the substrate, as well as the wire feed angle, significantly increased the amount of tungsten carbide particles retained in the cladding layer.

[0017] The preferred conditions are as follows:

[0018] In step (1), the 40Cr steel is processed into a size of 100mm×100mm×10mm using a cutting machine. The prepared substrate is cleaned with anhydrous ethanol to remove surface oil and dirt, and its surface is polished with an angle grinder to remove the oxide layer on its surface, ensuring that the surface to be melted is clean and tidy.

[0019] In step (2), in order to improve the hardness and wear resistance of the substrate surface, the composition of the flux-cored wire and the pre-placed powder is set as follows: 90% of dual-phase eutectic tungsten carbide particles; 9% of nickel powder; 1% of trace elements such as ferrosilicon; the powder filling rate is about 40%; and the outer sheath of the wire is made of pure nickel.

[0020] During the pre-powdering process, first, the powder prepared in step (2) is mixed evenly, and then mixed and stirred with binder (glass water) to make it a viscous state between solid and liquid. Finally, it is evenly spread on the surface to be fused and coated. It should be noted that the coating thickness should not be too thick or too thin, and should be controlled at about 1.5 mm.

[0021] In step (4), the welding process parameters are as follows: 99.9% argon is selected as the shielding gas, with a flow rate of 10 L / min; the tungsten electrode tip diameter is 3.2 mm, and it is positioned approximately 6 mm from the substrate surface; DC welding is used. The deposition current is 120-140 A, the cladding speed is 0.05 m / min, and the wire feed speed is 0.8-1.4 m / min. When the deposition current is 130 A, the cladding speed is 0.05 m / min, and the wire feed speed is 1.1 m / min, the resulting cladding layer exhibits the best performance.

[0022] In step (5), during the welding process optimization, a tungsten electrode tip oscillation process was incorporated into the welding program. This improves the morphology of the cladding layer and the distribution of tungsten carbide particles within it, preventing excessive settling. Furthermore, the wire feed angle and the distance between the tungsten electrode and the substrate also significantly affect the formation of the cladding layer. Process exploration revealed that a tungsten electrode distance of 6 mm from the substrate and a wire feed angle of approximately 23° resulted in a better cladding layer formation.

[0023] The wear-resistant cladding layer prepared above can achieve an overall hardness of over 630 HV1, and the wear loss volume is reduced to 0.33m³. 3 The efficiency was increased to approximately 3 times and 45 times that of the substrate, respectively.

[0024] Compared with the prior art, the advantages of this invention are:

[0025] 1. The wear-resistant cladding layer prepared using the process of this invention can achieve an overall hardness of over 630 HV1, and the wear loss volume is reduced to 0.33 μm. 3 The efficiency was increased to approximately 3 times and 45 times that of the substrate, respectively.

[0026] 2. The powder composition ratio provided by the present invention results in a good morphology of the cladding layer, free from defects such as pores and cracks, and a high bonding strength between the cladding layer and the substrate, making it less prone to peeling off during use.

[0027] 3. The process is simple, easy to operate, and has low equipment maintenance costs, making it suitable for actual production. Attached Figure Description

[0028] Figure 1 This is a macroscopic morphology diagram of the 40Cr steel planar wear-resistant cladding layer of the present invention;

[0029] Figure 2 This is a scanning electron microscope image of the 40Cr steel planar wear-resistant cladding layer of the present invention;

[0030] Figure 3 This is a diagram showing the hardness and wear loss of the 40Cr steel planar wear-resistant cladding layer of the present invention;

[0031] Figure 4 This is a wear morphology diagram of the 40Cr steel planar wear-resistant cladding layer of the present invention; Specific implementation methods

[0032] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with examples of this invention. The described embodiments are only some embodiments of this invention, and not all embodiments.

[0033] Specific embodiments of the present invention are as follows:

[0034] Example 1:

[0035] Substrate preparation: Using a cutting machine, 40Cr steel is processed into dimensions of 100mm×100mm×10mm, and the 100mm×10mm flat surface is used for subsequent cladding. At the same time, the prepared substrate is cleaned with anhydrous ethanol to remove surface oil and dirt, and the surface is polished with an angle grinder to remove the oxide layer, ensuring that the surface to be clad is clean and tidy.

[0036] Composition design of flux-cored welding wire and pre-placed powder: The composition of flux-cored welding wire and pre-placed powder is defined as follows: 90% duplex eutectic tungsten carbide particles; 9% nickel powder; 1% trace elements such as ferrosilicon; powder filling rate of about 40%; and the outer sheath of the welding wire is made of pure nickel.

[0037] Pre-coating process: Before cladding begins, a pre-coating layer containing tungsten carbide powder particles needs to be prepared on the surface to be clad. During pre-coating, the prepared powder is first uniformly mixed, then mixed with a binder (glass cleaner) until it reaches a viscous state between solid and liquid. Finally, it is evenly spread on the surface to be clad. It is important to note that the coating thickness should not be too thick or too thin; approximately 1.5 mm is ideal.

[0038] Selection of welding process parameters: TIG arc cladding process is selected, and its process parameters are as follows: 99.9% argon is selected as the shielding gas, the gas flow rate is 10L / min, the diameter of the tungsten electrode tip is 3.2mm, the distance from the substrate surface is about 6mm, DC welding is used, the cladding current is 120A, the cladding speed is 0.05m / min, and the wire feed speed is 0.8m / min.

[0039] Welding process optimization: During the welding process optimization, a tungsten electrode tip oscillation process was added to the welding program. This can improve the morphology of the cladding layer and the distribution of tungsten carbide particles in the cladding layer, preventing excessive sedimentation. In addition, the wire feed angle and the distance between the tungsten electrode and the substrate also have an important impact on the formation of the cladding layer. The tungsten electrode distance from the substrate was set to 6mm, and the wire feed angle was 23°.

[0040] The cladding layer prepared on a flat surface of 40Cr steel in Example 1 was subjected to hardness and wear tests, and the results are shown in Table 1. Table 1. Test results of the wear-resistant cladding layer prepared under the process parameters of Example 1.

[0041] As can be seen from Table 1, the microhardness of the wear-resistant cladding layer is significantly improved compared to the substrate, and its wear resistance is also significantly improved compared to the substrate.

[0042] Comparative Example 1:

[0043] The difference from Example 1 is that different welding process parameters (increasing wire feed speed) are used to prepare the wear-resistant cladding layer.

[0044] Selection of welding process parameters: TIG arc cladding process is selected, and its process parameters are as follows: 99.9% argon is selected as the shielding gas, the gas flow rate is 10L / min, the diameter of the tungsten electrode tip is 3.2mm, the distance from the substrate surface is about 6mm, DC welding is used, the cladding current is 120A, the cladding speed is 0.05m / min, and the wire feed speed is 1.1m / min.

[0045] The cladding layer prepared on the plane of 40Cr steel obtained in Comparative Example 1 was subjected to hardness and wear tests, and the results are shown in Table 2. Table 2. Test results of wear-resistant cladding prepared under the process parameters of Comparative Example 1

[0046] As can be seen from Table 2, the microhardness and wear resistance of the wear-resistant cladding layer prepared under different welding process parameters are significantly higher than the standard values ​​of the substrate.

[0047] Example 2:

[0048] Substrate preparation: Using a cutting machine, 40Cr steel is processed into dimensions of 100mm×100mm×10mm, and the 100mm×10mm flat surface is used for subsequent cladding. At the same time, the prepared substrate is cleaned with anhydrous ethanol to remove surface oil and dirt, and the surface is polished with an angle grinder to remove the oxide layer, ensuring that the surface to be clad is clean and tidy.

[0049] Composition design of flux-cored welding wire and pre-placed powder: The composition of flux-cored welding wire and pre-placed powder is defined as follows: 90% duplex eutectic tungsten carbide particles; 9% nickel powder; 1% trace elements such as ferrosilicon; powder filling rate of about 40%; and the outer sheath of the welding wire is made of pure nickel.

[0050] Pre-coating process: Before cladding begins, a pre-coating layer containing tungsten carbide powder particles needs to be prepared on the surface to be clad. During pre-coating, the prepared powder is first uniformly mixed, then mixed with a binder (glass cleaner) until it reaches a viscous state between solid and liquid. Finally, it is evenly spread on the surface to be clad. It is important to note that the coating thickness should not be too thick or too thin; approximately 1.5 mm is ideal.

[0051] Selection of welding process parameters: TIG arc cladding process is selected, and its process parameters are as follows: 99.9% argon is selected as the shielding gas, the gas flow rate is 10L / min, the diameter of the tungsten electrode tip is 3.2mm, the distance from the substrate surface is about 6mm, DC welding is used, the cladding current is 130A, the cladding speed is 0.05m / min, and the wire feed speed is 0.8m / min.

[0052] Welding process optimization: A tungsten electrode tip oscillation process was incorporated into the welding program, which improves the morphology of the cladding layer and the distribution of tungsten carbide particles within it, preventing excessive sedimentation. Furthermore, the wire feed angle and the distance between the tungsten electrode and the substrate also significantly affect the formation of the cladding layer; these were set to a 6mm distance between the tungsten electrode and the substrate, and a 23° wire feed angle.

[0053] The cladding layer prepared on the plane of 40Cr steel obtained in Example 2 was subjected to hardness and wear tests, and the results are shown in Table 3. Table 3. Test results of the wear-resistant cladding layer prepared under the process parameters of Example 2.

[0054] As can be seen from Table 3, the microhardness and wear resistance of the wear-resistant cladding prepared by increasing the welding heat input are significantly higher than the standard values ​​of the substrate, and are significantly improved compared with Example 1.

[0055] Comparative Example 2:

[0056] The difference from Example 2 is that different welding process parameters (increasing the wire feeding speed) are used to prepare the wear-resistant cladding layer.

[0057] Selection of welding process parameters: TIG arc cladding process is selected, and its process parameters are as follows: 99.9% argon is selected as the shielding gas, the gas flow rate is 10L / min, the diameter of the tungsten electrode tip is 3.2mm, the distance from the substrate surface is about 6mm, DC welding is used, the cladding current is 130A, the cladding speed is 0.05m / min, and the wire feed speed is 1.1m / min.

[0058] The cladding layer prepared on the plane of 40Cr steel obtained in Comparative Example 2 was subjected to hardness and wear tests, and the results are shown in Table 4. Table 4. Test results of the wear-resistant cladding layer prepared under the process parameters of Comparative Example 2.

[0059] As can be seen from Table 4, increasing the wire feed speed again under the condition of increased welding heat input significantly improved the microhardness and wear resistance of the prepared wear-resistant cladding layer.

[0060] Based on the above experimental results, it can be seen that by using the flux-cored wire with tungsten carbide particle powder composition ratio adopted in this invention, combined with the optimized TIG arc cladding process and cladding parameters, a wear-resistant cladding layer with good cladding morphology and high bonding strength with the substrate can be prepared on the plane of 40Cr steel. Moreover, the microhardness and wear resistance of the cladding layer are significantly improved compared with the substrate, thereby extending the service life of 40Cr steel workpieces and instruments.

Claims

1. A process for preparing a wear-resistant cladding layer containing tungsten carbide particles on a flat surface of 40Cr steel, characterized in that, The preparation steps are as follows: (1) Preparation of substrate: Use a cutting machine to process 40Cr steel into a size of 100mm×100mm×10mm, and use the 100mm×10mm flat surface for subsequent cladding. (2) Composition design of flux-cored wire and pre-placed powder: In order to improve the hardness and wear resistance of the substrate surface, the composition of flux-cored wire and pre-placed powder is selected from irregularly shaped tungsten carbide particles of different sizes, as well as nickel powder and a mixture of trace elements such as silicon iron. (3) Pre-coating process: This study adopts a combination of wire and powder. Before the cladding work begins, a pre-coating containing tungsten carbide particles needs to be prepared on the surface to be clad. (4) Selection of welding process parameters: This study uses TIG arc cladding process, and its process parameters are as follows: the shielding gas is 99.9% argon gas, the gas flow rate is 10L / min, the diameter of the tungsten electrode tip is 3.2mm, the distance from the substrate surface is about 6mm, DC welding is used, the cladding current is 120-140A, the cladding speed is 0.05m / min, and the wire feeding speed is 0.8-1.4m / min. (5) Optimization of welding process: In order to improve the forming quality of the cladding layer and improve the distribution of tungsten carbide particles in the cladding layer, a tungsten electrode oscillation process was added during the cladding process. In addition, by adjusting the distance between the tungsten electrode and the substrate and the wire feed angle, the content of tungsten carbide particles retained in the cladding layer was significantly increased.

2. The process for preparing a wear-resistant cladding layer containing tungsten carbide particles on a flat surface of 40Cr steel as described in claim (1), characterized in that, The 40Cr steel was processed into 100mm×100mm×10mm size using a cutting machine. The prepared substrate was cleaned with anhydrous ethanol to remove surface oil and dirt, and the surface was polished with an angle grinder to remove the oxide layer, ensuring that the surface to be melted was clean and tidy.

3. The process for preparing a wear-resistant cladding layer containing tungsten carbide particles on a flat surface of 40Cr steel as described in claim (2), characterized in that, To improve the hardness and wear resistance of the substrate surface, the composition of the flux-cored welding wire and the pre-placed powder is set as follows: 90% duplex eutectic tungsten carbide particles; 9% nickel powder; 1% trace elements such as ferrosilicon; the powder filling rate is about 40%; and the outer sheath of the welding wire is made of pure nickel.

4. The process for preparing a wear-resistant cladding layer containing tungsten carbide particles on a flat surface of 40Cr steel as described in claim (3), characterized in that, During the pre-powdering process, first, the powder prepared in step (2) is mixed evenly, and then mixed and stirred with binder (glass water) to make it a viscous state between solid and liquid. Finally, it is evenly spread on the surface to be fused and coated. It should be noted that the coating thickness should not be too thick or too thin, and should be controlled at about 1.5 mm.

5. The process for preparing a wear-resistant cladding layer containing tungsten carbide particles on a flat surface of 40Cr steel as described in claim (4), characterized in that, In selecting the welding process parameters, 99.9% argon was chosen as the shielding gas, with a flow rate of 10 L / min. The tungsten electrode tip diameter was 3.2 mm, positioned approximately 6 mm from the substrate surface, and DC welding was employed. The deposition current was 120-140 A, the cladding speed was 0.05 m / min, and the wire feed speed was 0.8-1.4 m / min. The cladding layer exhibited the best performance when the deposition current was 130 A, the cladding speed was 0.05 m / min, and the wire feed speed was 1.1 m / min.

6. The process for preparing a wear-resistant cladding layer containing tungsten carbide particles on a flat surface of 40Cr steel as described in claim (5), characterized in that, During the welding process optimization, a tungsten electrode tip oscillation technique was incorporated into the welding program. This improved the morphology of the cladding layer and the distribution of tungsten carbide particles within it, preventing excessive sedimentation. Furthermore, the wire feed angle and the distance between the tungsten electrode and the substrate also significantly impacted the cladding layer formation. Process exploration revealed that a tungsten electrode distance of 6mm from the substrate and a wire feed angle of approximately 23° resulted in optimal cladding layer formation.

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