A cladding material for hobbing cutter rings, a cladding layer, and the hobbing cutter ring.

Abstract

This invention provides a cladding material, a cladding layer, and a hobbing cutter ring for use. The cladding material comprises: 10-20% coated diamond, 2-5% MoS2, 2-5% B, 1-4% Si, 5-22% hard phase, 5-17% Cr, and 40-60% Co, Ni, or Fe; the hard phase includes one or more combinations of WC, TiC, TiN, VC, and NbC; the coated diamond is diamond powder externally coated with Fe, with diamond comprising 20-40% and Fe comprising 60-80%. This invention also provides a cladding layer made based on the above cladding material and a hobbing cutter ring with the cladding layer. This invention, by laser-cladding the above cladding material onto the surface of the cutter ring, has advantages such as high bonding strength with the substrate, a dense cladding layer, a fast heating rate, a small heat-affected zone, and will not cause excessive thermal damage to the hobbing cutter ring.

Description

Technical Field

[0001] This invention relates to a cladding material, cladding layer, and hobbing cutter ring for use as a hobbing cutter ring, belonging to the field of surface treatment for engineering equipment. Background Technology

[0002] During the excavation of underground projects such as tunnels and subways, the cutterhead of the tunnel boring machine drives the roller cutter to rotate. Rock breaking is mainly achieved by squeezing the rock with the roller cutter ring. If the roller cutter ring cannot meet the performance and life requirements, it is necessary to replace the cutter frequently. This not only greatly increases the cost of the cutter but also increases the replacement time and may even delay the project schedule. Therefore, the performance and life of the roller cutter ring have an important impact on the construction of underground projects.

[0003] The material of hobbing cutter rings is mainly ultra-high strength steel, but in extremely hard rocks or highly abrasive strata, the cutter rings still experience severe wear, leading to failure and replacement. Surface treatment processes can strengthen the surface of the base material and improve the lifespan of the workpiece. Among various surface treatment processes, electroplating results in thin coatings and weak adhesion; thermal spraying easily leads to diamond ablation and graphitization; and chemical vapor deposition produces thin coatings and is expensive, limiting its application. Laser cladding has advantages such as high bonding strength with the substrate and a dense cladding layer. It can form a wear-resistant cladding layer by laser cladding wear-resistant powder onto the workpiece surface, thereby increasing the wear resistance and lifespan of the workpiece, and its application has become increasingly widespread in recent years. Among various wear-resistant materials, diamond has the highest hardness and best wear resistance. However, laser cladding of diamond particles can easily cause the diamond to undergo a morphological transformation at high temperatures, partially transforming into graphite, resulting in a decrease in the hardness of the cladding layer and insufficient wear resistance.

[0004] Therefore, it is necessary to develop a new laser cladding material for hobbing cutter rings to improve their wear resistance and service life. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the purpose of this invention is to provide a laser cladding material for a hobbing cutter ring, wherein the cladding layer obtained by using the laser cladding material has high hardness and wear resistance.

[0006] To achieve the above objectives, the present invention provides a cladding material for hobbing cutter rings, wherein, by mass percentage, the composition of the cladding material for hobbing cutter rings comprises:

[0007] 10-20% coated diamond, 2-5% MoS2, 2-5% B, 1-4% Si, 5-22% hard phase, 5-17% Cr, 40-60% Co or Ni or Fe;

[0008] The hard phase includes one or more of WC, TiC, TiN, VC, and NbC, preferably WC;

[0009] The coated diamond is diamond powder with Fe coated on the outside. The diamond accounts for 20-40% and the Fe accounts for 60-80% of the total weight of the coated diamond (100%).

[0010] According to a specific embodiment of the present invention, among the above-mentioned cladding materials for hobbing cutter rings, diamond has the strongest wear resistance and can significantly increase the hardness and wear resistance of the cladding layer; in addition, diamond micro powder has a large specific surface area effect, the coefficient of friction decreases significantly, and it has a good friction-reducing effect.

[0011] MoS2 has a low coefficient of friction, which can effectively reduce friction.

[0012] Borosilicate (B) primarily functions to deoxidize and slag. During laser cladding, it preferentially reacts with oxygen in the alloy powder and oxides on the material surface to form low-melting-point borosilicates, thereby protecting other elements. In addition, it has good self-lubricating properties, which can reduce the coefficient of friction and improve wear resistance. However, excessive B content can easily lead to cracking.

[0013] Si mainly functions as a deoxidizer and slagging agent;

[0014] WC particles, as a hard phase, can significantly increase the wear resistance, melting point, fracture toughness, and thermal conductivity of the cladding layer, and can reduce the thermal impact on diamond. However, excessive WC content can easily lead to cracking. This invention uses two hard phases, diamond and WC, to avoid cracking caused by excessive content of a single hard phase, thereby improving the life of the hobbing cutter ring.

[0015] Cr can improve the oxidation resistance and thermal strength of the cladding layer;

[0016] Co serves as the binder phase. Furthermore, Co-based alloy coatings exhibit good self-fluxing properties, high-temperature resistance, and thermal shock resistance.

[0017] Fe, as a coating material, has a high specific heat capacity and a high melting point. It can absorb heat and melt in the cladding layer, reducing or avoiding the impact of high temperature on diamond, and it is also low in cost.

[0018] According to a specific embodiment of the present invention, preferably, the coated diamond is prepared by the following method:

[0019] After the Fe is melted, it is poured out from top to bottom, and diamond particles are sprayed out from below the Fe solution using a nozzle, so that the surface of the diamond particles is coated with a layer of Fe. Then, it is immediately cooled with brine to obtain coated diamond particles. Preferably, the angle between the spraying direction and the horizontal direction is 20°-45°.

[0020] According to a specific embodiment of the present invention, preferably, the diamond particles have a particle size of 150-325 mesh.

[0021] According to a specific embodiment of the present invention, preferably, the speed at which diamond particles are ejected from the nozzle is 5-15 m / s.

[0022] The present invention also provides a cladding layer, wherein the cladding layer is prepared by laser cladding using the cladding material described above for the roller cutter ring, and the thickness of the cladding layer is 0.5-2 mm.

[0023] According to a specific embodiment of the present invention, preferably, the preparation process of the above-mentioned cladding layer includes the following specific steps:

[0024] Preheat the hob cutter ring substrate;

[0025] Laser cladding powder, made from cladding material for roller cutter rings, is coated onto the surface of a preheated roller cutter ring substrate, and then laser cladding is performed to form a cladding layer.

[0026] The roller cutter ring, after laser cladding, is heat-insulated and then air-cooled to remove residual stress.

[0027] According to a specific embodiment of the present invention, preferably, in the preparation process of the above-mentioned cladding layer, the preheating temperature is 200-300℃ and the holding time is 1-3h.

[0028] According to a specific embodiment of the present invention, preferably, in the process of preparing the above-mentioned cladding layer, the laser power of laser cladding is 1-3 kW, the laser spot diameter is 3-10 mm, the scanning speed is 150-300 mm / min, and the protective gas is argon.

[0029] According to a specific embodiment of the present invention, preferably, in the preparation process of the above-mentioned cladding layer, the temperature of the heat preservation treatment is 220-350℃, and the heat preservation time is 1-4h.

[0030] According to a specific embodiment of the present invention, preferably, the preparation process of the cladding layer may include the following specific steps:

[0031] Step 1: Pre-treat the blade ring substrate by grinding and polishing the surface, then cleaning it with anhydrous ethanol;

[0032] Step 2: Perform ultrasonic cleaning on the diamond particles and powder materials;

[0033] Step 3: Prepare diamond-coated material. The coating material is Fe particles. After melting Fe, pour it out from top to bottom. Use a nozzle to spray diamond particles from below the Fe solution, so that the surface of the diamond is coated with a layer of Fe. Then immediately cool it with brine to obtain diamond-coated particles. The particle size of the diamond particles is 150-325 mesh. The speed of the liquid sprayed from the nozzle is 5-15 m / s.

[0034] Step 4: Prepare cladding powder. Mix all the components of the cladding material evenly, put it into a ball mill for grinding for 30-90 minutes to obtain laser cladding powder, and then put it into a drying oven to dry at a temperature of 120-200℃ for 30-60 minutes.

[0035] Step 5: Preheat the blade ring substrate to prevent cracking of the cladding layer. The preheating temperature is 200-300℃, and the holding time is 1-3 hours.

[0036] Step 6: Perform laser cladding. Use a laser to clad the laser cladding powder obtained in Step 4 onto the blade ring substrate material. The laser power is 1-3kW, the laser spot diameter is 3-10mm, the scanning speed is 150-300mm / min, the cladding layer thickness is 0.5-2mm, and the protective gas is argon.

[0037] Step 7: After laser cladding, the blade ring is kept at a high temperature in a heat treatment furnace to remove residual stress. The holding temperature is 220-350℃ and the holding time is 1-4 hours, followed by air cooling.

[0038] The present invention also provides a hobbing cutter ring, wherein the surface of the hobbing cutter ring has the above-mentioned cladding layer.

[0039] In the cladding material for roller cutter rings provided by this invention, diamond particles coated with Fe can reduce the heat input of diamond during laser cladding, lower the diamond temperature during laser cladding, and reduce or avoid the impact of the high temperature generated by laser cladding on the hardness and wear resistance of diamond, effectively increasing the hardness and wear resistance of the cladding layer of the cutter ring. MoS2 powder can effectively reduce friction, thereby reducing the wear of the roller cutter ring. Other elements have high melting points and high thermal conductivity, which can effectively reduce the temperature of diamond and reduce or avoid the transformation of diamond into graphite. In addition, this invention uses two hard phases, diamond and WC, which can avoid cracking caused by excessive content of a single hard phase and improve the life of the roller cutter ring. Rock debris produced after the roller cutter breaks rocks will adhere to the surface of the roller cutter, reducing the rock breaking efficiency and easily causing uneven wear of the roller cutter. The cladding material of this invention forms a cladding layer on the surface of the cutter ring, which can reduce the adhesion between the roller cutter surface and rock debris, and reduce uneven wear of the roller cutter. In addition, the roller cutter generates vibration and impact when breaking rocks, which can easily lead to the breakage and failure of the roller cutter ring. The cladding layer provided by this invention can reduce the vibration caused by the roller cutter breaking rocks, help reduce abnormal damage to the roller cutter, and ensure equipment safety.

[0040] This invention combines liquid Fe with sprayed diamond, coating the diamond particles with Fe. This reduces the temperature of the diamond during laser cladding, minimizing or eliminating the impact of the high temperatures generated during laser cladding on the diamond's hardness and wear resistance. Furthermore, diamond micropowder has a small particle size and large specific surface area, leading to uneven coatings and particle agglomeration during surface plating processes such as electroless plating and electroplating, affecting its usability. This invention utilizes a nozzle to coat the diamond surface with a layer of molten iron, followed by rapid cooling. This results in a uniformly distributed coating of diamond, preventing agglomeration and solving the problems associated with diamond micropowder.

[0041] This invention utilizes laser cladding of a diamond-containing material onto the cutter ring surface. This process offers advantages such as high bonding strength with the substrate, a dense cladding layer, rapid heating, and a small heat-affected zone, minimizing thermal damage to the cutter ring. The cladding layer also reduces adhesion between the cutter surface and rock debris, minimizing cutter wear. Furthermore, the cladding layer reduces vibrations caused by the cutter breaking rock, ensuring the safety of the tunneling equipment. Detailed Implementation

[0042] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0043] Example 1

[0044] This embodiment provides a cladding layer, wherein, by mass percentage, the composition of the cladding material used to prepare the cladding layer includes: 10% coated diamond, 2% MoS2, 2% B, 4% Si, 5% WC, 17% Cr, and 60% Co.

[0045] The diamond powder contains 20% diamond by mass and 80% Fe by mass.

[0046] The coated diamond powder is prepared by the following steps:

[0047] After melting Fe, it is poured out from top to bottom. Diamond particles are sprayed out from below the Fe solution using a nozzle (at an angle of 30° with the horizontal direction), so that the surface of the diamond particles is coated with a layer of Fe. Then, it is immediately cooled with brine to obtain diamond-coated particles. The diamond particles have a particle size of 200 mesh, and the speed at which the diamond particles are sprayed from the nozzle is 8 m / s.

[0048] The cladding material for this cladding layer is used in the form of laser cladding powder. Specifically, it is obtained by mixing various components and grinding them in a ball mill for 90 minutes. After grinding, the laser cladding powder is placed in a drying oven to dry at 150°C for 50 minutes.

[0049] The method for preparing the cladding layer in this embodiment includes the following steps:

[0050] Step 1: Pre-treat the blade ring substrate by grinding and polishing the surface, then cleaning it with anhydrous ethanol;

[0051] Step 2: Preheat the blade ring substrate to prevent cracking of the cladding layer. The preheating temperature is 200℃ and the holding time is 3 hours.

[0052] Step 3: Laser cladding is performed on the laser cladding powder coated on the blade ring substrate using a laser. The laser power is 1.5kw, the laser spot diameter is 3mm, the scanning speed is 300mm / min, the cladding layer thickness is 0.5mm, and the protective gas is argon.

[0053] Step 4: The laser-clad blade ring is kept at a temperature of 350℃ in a heat treatment furnace to remove residual stress. The holding time is 1 hour, and then it is air-cooled to complete the preparation of the cladding layer.

[0054] Example 2

[0055] This embodiment provides a cladding layer, wherein, by mass percentage, the composition of the cladding material used to prepare the cladding layer includes: 20% coated diamond, 5% MoS2, 5% B, 3% Si, 22% WC, 5% Cr, and 40% Co.

[0056] The diamond powder contains 25% diamond by mass and 75% Fe by mass.

[0057] The coated diamond powder is prepared by the following steps:

[0058] After melting Fe, it is poured out from top to bottom. Diamond particles are sprayed out from below the Fe solution using a nozzle (at an angle of 30° with the horizontal direction), so that the surface of the diamond particles is coated with a layer of Fe. Then, it is immediately cooled with brine to obtain diamond-coated particles. The diamond particles have a particle size of 325 mesh, and the speed at which the diamond particles are sprayed from the nozzle is 5 m / s.

[0059] The cladding material for this cladding layer is used in the form of laser cladding powder. Specifically, it is obtained by mixing various components and grinding them in a ball mill for 60 minutes. After grinding, the laser cladding powder is placed in a drying oven to dry at 120°C for 60 minutes.

[0060] The method for preparing the cladding layer in this embodiment includes the following steps:

[0061] Step 1: Pre-treat the blade ring substrate by grinding and polishing the surface, then cleaning it with anhydrous ethanol;

[0062] Step 2: Preheat the blade ring substrate to prevent cracking of the cladding layer. The preheating temperature is 300℃ and the holding time is 1 hour.

[0063] Step 3: Laser cladding is performed on the laser cladding powder coated on the blade ring substrate using a laser. The laser power is 1.5kw, the laser spot diameter is 10mm, the scanning speed is 250mm / min, the cladding layer thickness is 2mm, and the protective gas is argon.

[0064] Step 4: The laser-clad blade ring is kept at a temperature of 270℃ for 3 hours in a heat treatment furnace to remove residual stress, and then air-cooled to complete the preparation of the cladding layer.

[0065] Example 3

[0066] This embodiment provides a cladding layer, wherein, by mass percentage, the composition of the cladding material used to prepare the cladding layer includes: 15% coated diamond, 4% MoS2, 3% B, 1% Si, 15% WC, 15% Cr, and 47% Co.

[0067] The diamond powder contains 40% diamond by mass and 60% Fe by mass.

[0068] The coated diamond powder is prepared by the following steps:

[0069] After melting Fe, it is poured out from top to bottom. Diamond particles are sprayed out from below the Fe solution using a nozzle (at an angle of 30° with the horizontal direction), so that the surface of the diamond particles is coated with a layer of Fe. Then, it is immediately cooled with brine to obtain diamond-coated particles. The diamond particles have a particle size of 150 mesh, and the speed at which the diamond particles are sprayed from the nozzle is 15 m / s.

[0070] The cladding material for this cladding layer is used in the form of laser cladding powder. Specifically, it is obtained by mixing various components and grinding them in a ball mill for 30 minutes. After grinding, the laser cladding powder is placed in a drying oven to dry at 200°C for 30 minutes.

[0071] The method for preparing the cladding layer in this embodiment includes the following steps:

[0072] Step 1: Pre-treat the blade ring substrate by grinding and polishing the surface, then cleaning it with anhydrous ethanol;

[0073] Step 2: Preheat the blade ring substrate to prevent cracking of the cladding layer. The preheating temperature is 260℃ and the holding time is 2 hours.

[0074] Step 3: Laser cladding is performed on the laser cladding powder coated on the blade ring substrate using a laser. The laser power is 1.5kw, the laser spot diameter is 5mm, the scanning speed is 150mm / min, the cladding layer thickness is 1mm, and the protective gas is argon.

[0075] Step 4: The laser-clad blade ring is kept at a temperature of 220℃ for 4 hours in a heat treatment furnace to remove residual stress, and then air-cooled to complete the preparation of the cladding layer.

[0076] Comparative Example 1:

[0077] No cladding layer, only the blade ring base, made of H13 steel.

[0078] Comparative Example 2

[0079] The cladding material in this comparative example is the same as that in Example 1, except for the preparation method. Preparation method: The cladding material, including diamond, is directly ball-milled and mixed evenly before laser cladding. The diamond is not coated again, and the remaining processes are the same.

[0080] Comparative Example 3

[0081] This comparative example provides a cladding layer, wherein, by mass percentage, the composition of the cladding material used to prepare the cladding layer includes: 13% coated diamond, 4% MoS2, 3% B, 3% Si, 15% WC, 15% Cr, and 47% Co.

[0082] The diamond powder contains 30% diamond by mass and 70% Fe by mass.

[0083] The coated diamond powder is prepared by the following steps:

[0084] After melting Fe, it is poured out from top to bottom. Diamond particles are sprayed out from below the Fe solution using a nozzle (at an angle of 30° with the horizontal direction), so that the surface of the diamond particles is coated with a layer of Fe. Then, it is immediately cooled with brine to obtain diamond-coated particles. The diamond particles have a particle size of 150 mesh, and the speed at which the diamond particles are sprayed from the nozzle is 25 m / s.

[0085] The cladding material for this cladding layer is used in the form of laser cladding powder. Specifically, it is obtained by mixing various components and grinding them in a ball mill for 30 minutes. After grinding, the laser cladding powder is placed in a drying oven to dry at 200°C for 30 minutes.

[0086] The preparation method of the cladding layer in this comparative example includes the following steps:

[0087] Step 1: Pre-treat the blade ring substrate by grinding and polishing the surface, then cleaning it with anhydrous ethanol;

[0088] Step 2: Preheat the blade ring substrate to prevent cracking of the cladding layer. The preheating temperature is 260℃ and the holding time is 2 hours.

[0089] Step 3: Laser cladding is performed on the laser cladding powder coated on the blade ring substrate using a laser. The laser power is 1.5kw, the laser spot diameter is 5mm, the scanning speed is 400mm / min, the cladding layer thickness is 1mm, and the protective gas is argon.

[0090] Step 4: The laser-clad blade ring is kept at a temperature of 220℃ for 4 hours in a heat treatment furnace to remove residual stress, and then air-cooled to complete the preparation of the cladding layer.

[0091] Comparative Example 4

[0092] The cladding material in this comparative example does not contain diamond, has a WC content of 42%, and the contents of other materials are the same as in Example 2. Because it does not contain diamond, the preparation method does not involve coating; the other preparation methods are the same as in Example 2. Cracking occurred in the roller cladding layer after cladding.

[0093] To compare the differences in cladding layer particle size distribution, wear resistance, and vibration performance between the embodiments of the present invention and the comparative examples, the particle size distribution of the coated diamond was statistically analyzed. The average particle size of the Fe-coated diamond is shown in Table 1.

[0094] Samples of the same size (1.9 inches in diameter) were selected for reciprocating wear tests using a roller cutter. The test material was granite with a compressive strength of approximately 100 MPa. The rock sample dimensions were 320 mm × 100 mm × 100 mm. The test thrust was 3 kN, the single stroke of the sample was 290 mm, the linear velocity was 50 mm / s, and the wear test duration was 2 hours. Vibration data during the test was recorded using a vibration sensor at a frequency of 256 Hz. Before the wear test, the hardness of the substrate, the hardness of the cladding layer, and the depth of the cladding layer were measured. After the wear test, the weight loss due to wear was measured, and the diamond burn-off was observed. The results are shown in Table 2.

[0095] When the cutter is breaking rocks, it will be subjected to strong vibration and impact. Excessive vibration will cause the cutter ring to crack. The vibration situation during the wear test is shown in Table 3.

[0096] Table 1 Average particle size of coated diamond particles

[0097] Example 1 130±12 Example 2 92±10 Example 3 158±14 Comparative Example 3 143±10

[0098] Table 2 Wear loss weight of the cutter ring after wear test

[0099]

[0100]

[0101] Table 3 Vibration of the cutter ring during the wear test

[0102] Example 1 14.6 Example 2 8.4 Example 3 12.8 Comparative Example 1 25.0 Comparative Example 2 20.7 Comparative Example 3 18.5

[0103] Table 1 shows the average particle size of the Fe-coated diamond. The experimental results in Table 1 show that the average particle size of the Fe-coated diamond is relatively small and uniform.

[0104] As can be seen from the experimental results in Table 2, compared with Comparative Examples 1-3, the diamonds in Examples 1-3 did not ablate, indicating that the technical solution of the present invention helps to avoid diamond ablation. Moreover, although the hardness and depth of the cladding layer in Examples 1-3 are different, resulting in different wear loss weights, they are all lower than 2.30g, which is lower than that in Comparative Examples 1-3, indicating that the technical solution of the present invention improves the wear resistance of the cladding layer.

[0105] The experimental results in Table 3 show that the vibration acceleration of Comparative Examples 1-3 is 18.5 m / s². 2 The vibration acceleration in Examples 1-3 is <15m / s². 2 As can be seen, the technical solution of the present invention effectively reduces the vibration acceleration of the cutter ring when breaking rock, thereby helping to improve the service life of the cutter ring.

Claims

1. A cladding material for hobbing cutter rings, wherein, The composition of the cladding material for hobbing cutter rings, by weight percentage, includes: 10-20% coated diamond, 2-5% MoS2, 2-5% B, 1-4% Si, 5-22% hard phase, 5-17% Cr, 40-60% Co or Ni or Fe. The hard phase includes one or more of WC, TiC, TiN, VC, and NbC; The coated diamond is diamond powder with Fe coated on the outside, wherein, based on the mass of the coated diamond as 100%, the proportion of diamond is 20-40% and the proportion of Fe is 60-80%. The coated diamond is prepared by the following method: Fe is melted and poured out from top to bottom. Diamond particles are sprayed out from below the Fe solution using a nozzle, so that the surface of the diamond particles is coated with a layer of Fe. Then, it is immediately cooled with brine to obtain coated diamond particles. The speed of spraying the diamond particles using the nozzle is 5-15 m / s, the angle between the spraying direction and the horizontal direction is 20°-45°, and the particle size of the diamond particles is 150-325 mesh.

2. A cladding layer, wherein, The cladding layer is prepared by laser cladding using the cladding material for the roller cutter ring as described in claim 1, and the thickness of the cladding layer is 0.5-2 mm; The laser power of the laser cladding is 1-3kW, the laser spot diameter is 3-10mm, the scanning speed is 150-300mm / min, and the protective gas is argon.

3. The cladding layer according to claim 2, wherein, The preparation process includes the following specific steps: Preheat the hob cutter ring substrate; Laser cladding powder, made from cladding material for roller cutter rings, is coated onto the surface of a preheated roller cutter ring substrate, and then laser cladding is performed to form a cladding layer. The roller cutter ring, after laser cladding, is heat-insulated and then air-cooled to remove residual stress.

4. The cladding layer according to claim 3, wherein, The preheating temperature is 200-300℃, and the holding time is 1-3 hours.

5. The cladding layer according to claim 3, wherein, The heat preservation treatment is carried out at a temperature of 220-350℃ for 1-4 hours.

6. A hobbing cutter ring, wherein, The surface of the hobbing cutter ring has the cladding layer as described in any one of claims 2-5.

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