Wear-resistant alloy powder, wear-resistant steel belt, surface strengthening method of wear-resistant steel belt and heading machine main drive sealing runway

Abstract

The invention provides wear-resistant alloy powder, a wear-resistant steel belt, a surface strengthening method of the wear-resistant steel belt and a main drive sealing runway of a heading machine. The alloy powder comprises, by mass, 1.5%-5.0% of C, 0%-30.0% of Cr, 7%-80% of W, 10%-59% of Co, 0.6%-1.5% of Mo and the balance S, and the sum of the mass of all the components is 100%. According to the surface strengthening method of the wear-resistant steel belt, the wear-resistant coating is obtained on the surface of the steel belt material by regulating and controlling the components and proportion of the wear-resistant alloy powder and adopting a high velocity oxy-fuel spraying technology, and the steel belt subjected to surface strengthening has good wear resistance, so that the service life of a sealing runway can be prolonged; besides, in combination with the special sealing runway structural design, the wear-resistant steel belt can be mounted and replaced by detaching the bolts and the expansion rings, so that a large amount of time cost and labor cost are saved.

Description

Technical Field

[0001] The invention belongs to the technical field of main drive sealed runways of tunnel boring machines, and in particular relates to wear-resistant alloy powder, wear-resistant steel belt and surface strengthening method thereof, and main drive sealed runways of tunnel boring machines. Background Art

[0002] The main drive system of the tunnel boring machine provides power for the cutter head of the tunnel boring machine to cut and break rocks, and is the core system of the tunnel boring machine. In order to avoid damage to the main bearing in the main drive system, two sets of main drive sealing systems are designed near the main bearing to prevent mud and sand in the external environment from entering the main bearing. The main drive sealing system consists of a sealing runway and a lip seal. There are currently two forms of sealing runways. One is composed of an integral large alloy ring. The material of the alloy large ring is surface-hardened low-alloy steel, which has poor surface wear resistance and a small size in the tunnel. The large ring cannot be replaced after severe surface wear, and on-site maintenance requires more than 15 days; the other is composed of a sealing runway support ring and a wear-resistant steel belt. The wear-resistant steel belt is fixed on the support ring by a hot-loading process. The wear-resistant steel belt can be replaced, but it needs to be hot-loaded in the tunnel, which requires a large number of workers and high operating technology. At the same time, the existing wear-resistant steel belt material has poor wear performance.

[0003] Therefore, there is a need for a wear-resistant steel belt with better wear resistance and a sealed runway structure that is easy to install and replace, so as to solve the problems in the prior art of poor wear resistance of the main drive sealed runway, complex replacement process of the wear-resistant steel belt, and great difficulty in replacement. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a wear-resistant alloy powder, a wear-resistant steel belt and a surface strengthening method thereof, and a main drive sealed runway of a tunnel boring machine. By preparing the wear-resistant alloy powder and forming a wear-resistant coating on the surface of the steel belt, the wear-resistant steel belt has excellent wear resistance, and combined with the structural design of the sealed runway, the wear-resistant steel belt can be quickly installed and replaced in the sealed runway.

[0005] To achieve the above-mentioned purpose, the present invention provides a wear-resistant alloy powder, wherein the alloy powder comprises: C: 1.5%-5.0%, Cr: 0%-30.0%, W: 7%-80%, Co: 10%-59%, Mo: 0.6%-1.5%, and the remainder is S element, and the sum of the masses of each component is 100%.

[0006] According to a specific embodiment of the present invention, preferably, the particle size of the alloy powder is 15-45 μm. Among them, C, W and Cr exist in the form of hard phase, so that the prepared coating has excellent wear resistance and hardness, and Co is distributed between W and C to bond the hard phase and the matrix material together.

[0007] According to a specific embodiment of the present invention, preferably, the alloy powder includes: C: 3%-5%, Cr: 0%-10%, W: 30%-80%, Co: 10%-30%, Mo: 0.6%-1.2%, and the remainder is S element, and the sum of the masses of each component is 100%.

[0008] The present invention also provides a surface strengthening method for a wear-resistant steel belt, wherein the surface strengthening method comprises: forming a wear-resistant coating on the surface of the wear-resistant steel belt where strengthening is required; the wear-resistant coating is prepared from the above-mentioned wear-resistant alloy powder; the area to be strengthened may be the entire surface or a part thereof.

[0009] According to a specific embodiment of the present invention, preferably, the surface strengthening method specifically comprises the following steps:

[0010] S1. Clean the parts of the wear-resistant steel belt that need to be strengthened;

[0011] S2, performing sandblasting on the surface of the wear-resistant steel belt obtained in S1 where the part that needs to be strengthened;

[0012] S3, preheating the wear-resistant steel strip obtained in S2, with the preheating temperature being 150-250°C;

[0013] S4, using supersonic flame spraying, spraying the wear-resistant alloy powder on the surface of the wear-resistant steel belt obtained in S3 where the wear-resistant alloy powder needs to be strengthened to form a wear-resistant coating, thereby completing the surface strengthening of the wear-resistant steel belt. The surface strengthening method can be used to prepare a new wear-resistant steel belt or to repair a worn wear-resistant steel belt.

[0014] In some specific embodiments, preferably, when the surface strengthening method is used to repair a worn wear-resistant steel belt, it specifically includes the following steps:

[0015] S1. Clean the parts of the wear-resistant steel belt that need to be repaired;

[0016] S2, performing sandblasting on the surface of the wear-resistant steel belt obtained in S1 where the repaired part is required;

[0017] S3, preheating the wear-resistant steel strip obtained in S2, with the preheating temperature being 150-250°C;

[0018] S4. Using supersonic flame spraying, spray the wear-resistant alloy powder on the surface of the wear-resistant steel belt obtained in S3 that needs to be repaired to form a wear-resistant coating, thereby completing the repair of the wear-resistant steel belt.

[0019] In some specific embodiments, preferably, the solution for cleaning the wear-resistant steel belt is acetone, which is used to remove oil, dust and other impurities.

[0020] According to a specific embodiment of the present invention, preferably, the oxygen flow rate of the supersonic flame spraying is 720-800L / min, the kerosene amount is 12-20L / h, the powder feeding amount is 70-90g / min, and the spraying distance is 200-300mm. In the present invention, the wear-resistant coating is prepared on the surface of the wear-resistant steel belt material substrate by supersonic flame spraying, and the heat input is small, which can reduce the thermal damage to the wear-resistant steel belt substrate material, and obtain a coating with good wear resistance, resist the invasion of abrasive particles in the working environment, and make the sealed runway have a longer service life. Since the wear-resistant steel belt is thin, preheating before supersonic flame spraying can prevent deformation.

[0021] According to a specific embodiment of the present invention, preferably, the sand particles for sand blasting are 60-80 mesh corundum sand, the sand blasting angle is 60-75°, and the sand blasting pressure is 0.40-0.50 MPa.

[0022] The present invention also provides a wear-resistant steel belt, wherein the wear-resistant steel belt is obtained by surface strengthening by the above surface strengthening method; the surface of the wear-resistant steel belt contains a wear-resistant coating. The wear-resistant steel belt is made of alloy steel.

[0023] According to a specific embodiment of the present invention, preferably, the hardness of the wear-resistant steel belt is ≥500HV; the surface roughness of the wear-resistant steel belt is ≤Ra2.1μm; the coating porosity of the wear-resistant steel belt is ≤2.0%; the wear weight loss of the wear-resistant steel belt is ≤269mg. The experimental conditions for the wear weight loss are: the mass percentage of hard abrasive garnet in the wear medium is 30%, the wear time is 150min, and the rotation speed is 200rmp.

[0024] According to a specific embodiment of the present invention, preferably, the hardness of the wear-resistant steel belt is 500-1300 HV; the surface roughness of the wear-resistant steel belt is Ra1.6 μm to Ra2.1 μm; the coating porosity of the wear-resistant steel belt is 1.1%-2.0%; the wear weight loss of the wear-resistant steel belt is 59-269 mg. The experimental conditions for the wear weight loss are: the mass percentage of hard abrasive garnet in the wear medium is 30%, the wear time is 150 min, and the rotation speed is 200 rpm.

[0025] The present invention also provides a main drive sealed runway for a tunnel boring machine, wherein the sealed runway comprises a support ring, an expansion ring and the above-mentioned wear-resistant steel belt; the upper surface of the support ring is an inclined surface; the cross-section of the expansion ring is a right triangle or a right trapezoid, and is located on the upper surface of the support ring; the wear-resistant steel belt is located on the upper surface of the expansion ring.

[0026] According to a specific embodiment of the present invention, preferably, the sealing runway comprises a support ring, a wear-resistant steel belt, an expansion ring and a pressure ring; the upper surface of the support ring is an inclined surface; the cross section of the expansion ring is a right triangle or a right trapezoid, and is located on the upper surface of the support ring; the wear-resistant steel belt is located on the upper surface of the expansion ring, so that the sealing runway has good wear resistance;

[0027] The pressure ring is detachably arranged on the outer side of the support ring and is fixed to the side of the support ring by bolts, and is tightly connected to the support ring. The bolts are provided with matching gaskets.

[0028] The expansion ring, the pressure ring and the bolt cooperate with each other to fix the wear-resistant steel belt, and also facilitate the disassembly of the wear-resistant steel belt.

[0029] According to a specific embodiment of the present invention, the sealed runway is further provided with other necessary components, which can be specifically arranged in a conventional manner.

[0030] In the present invention, through the special structure of the sealing track, the wear-resistant steel belt can be quickly installed and replaced by removing the bolts and the expansion ring.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The surface strengthening method of the wear-resistant steel belt provided by the present invention obtains a wear-resistant coating on the surface of the steel belt material by adjusting the composition and proportion of the wear-resistant alloy powder and adopting the supersonic flame spraying technology. The surface strengthened steel belt has good wear resistance, thereby being able to increase the service life of the sealed runway to meet the working requirements of the sealed runway.

[0033] (2.) The main drive sealed runway of the tunnel boring machine provided by the present invention has a special sealed runway structure design. The installation and replacement of the wear-resistant steel belt can be achieved by removing the bolts and expansion rings, thereby saving a lot of time and labor costs, improving construction safety, and realizing the long-distance use of the main drive sealed runway. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic cross-sectional structure diagram of the main drive sealed runway of the tunnel boring machine in the present invention.

[0035] Figure 2 It is a schematic diagram of the structure of the support ring in the present invention.

[0036] Description of main figures:

[0037] Support ring 1, wear-resistant steel belt 2, expansion ring 3, pressure ring 4, bolt 5, gasket 6. DETAILED DESCRIPTION

[0038] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0039] Example 1

[0040] This embodiment provides a main drive sealed runway for a tunnel boring machine, wherein the sealed runway has the following structure:

[0041] like Figure 1 As shown, the sealing runway includes a support ring 1, a wear-resistant steel belt 2, an expansion ring 3 and a pressure ring 4; the upper surface of the support ring 1 is an inclined surface; the cross-section of the expansion ring 3 is a right triangle and is located on the upper surface of the support ring 1; the wear-resistant steel belt 2 is located on the upper surface of the expansion ring 3, so that the sealing runway has good wear resistance;

[0042] The pressure ring 4 is detachably arranged on the outer side of the support ring 1 and is fixed to the side of the support ring 1 by bolts 5 and is tightly connected to the support ring 1. Figure 2 As shown, the bolt 5 is provided with an adapted gasket 6;

[0043] The expansion ring 3, the pressure ring 4 and the bolt 5 cooperate with each other to fix the wear-resistant steel belt 2, and also facilitate the removal of the wear-resistant steel belt 2; the sealing runway is also provided with other necessary components, which can be specifically arranged in a conventional manner.

[0044] This embodiment also provides a surface strengthening method for a wear-resistant steel belt, the surface strengthening method comprising the following steps:

[0045] (1) Preparation of wear-resistant alloy powder:

[0046] The wear-resistant alloy powder comprises the following components: C: 5.0%, Cr: 3.5%, W: 80.0%, Co: 10.0%, Mo: 1.0%, and the balance is S element, and the sum of the masses of the components is 100%; the powder particle size is 15-35 μm.

[0047] (2) Strengthen the surface of wear-resistant steel belt:

[0048] S1. Use acetone to clean the surface of the wear-resistant steel belt of the sealed runway where the parts need to be strengthened, and remove oil, dust and other impurities;

[0049] S2. Sandblast the parts of the wear-resistant steel belt that need to be strengthened. The sandblasting sand is 60 mesh corundum sand, the sandblasting angle is 75°, and the sandblasting pressure is 0.40MPa;

[0050] S3, preheating the wear-resistant steel belt at a temperature of 250°C;

[0051] S4, spraying the wear-resistant alloy powder on the surface of the wear-resistant steel belt where reinforcement is required by supersonic flame spraying to form a wear-resistant coating, thereby completing the surface reinforcement of the wear-resistant steel belt;

[0052] Among them, the process parameters of supersonic flame spraying are: oxygen flow rate 720L / min, kerosene volume 12L / h, powder feeding volume 90g / min, and spraying distance 200mm.

[0053] Example 2

[0054] This embodiment adopts the same structure as the main drive sealed runway of the tunnel boring machine in Embodiment 1, but the surface strengthening method of the wear-resistant steel belt is different. The surface strengthening method includes the following steps:

[0055] (1) Preparation of wear-resistant alloy powder:

[0056] The wear-resistant alloy powder comprises the following components: C: 4.5%, W: 64%, Co: 30.5%, Mo: 0.6%, and the remainder is S element, and the sum of the masses of the components is 100%; the powder particle size is 20-40 μm.

[0057] (2) Strengthen the surface of wear-resistant steel belt:

[0058] S1. Use acetone to clean the surface of the wear-resistant steel belt of the sealed runway where the parts need to be strengthened, and remove oil, dust and other impurities;

[0059] S2. Sandblast the parts of the wear-resistant steel belt that need to be strengthened. The sandblasting sand is 70 mesh corundum sand, the sandblasting angle is 65°, and the sandblasting pressure is 0.45MPa;

[0060] S3, preheating the wear-resistant steel belt at a temperature of 200°C;

[0061] S4, spraying the wear-resistant alloy powder on the surface of the wear-resistant steel belt where reinforcement is required by supersonic flame spraying to form a wear-resistant coating, thereby completing the surface reinforcement of the wear-resistant steel belt;

[0062] Among them, the process parameters of supersonic flame spraying are: oxygen flow rate 760L / min, kerosene volume 16L / h, powder feeding volume 80g / min, and spraying distance 250mm.

[0063] Example 3

[0064] This embodiment adopts the same structure as the main drive sealed runway of the tunnel boring machine in Embodiment 1, but the surface strengthening method of the wear-resistant steel belt is different. The surface strengthening method includes the following steps:

[0065] (1) Preparation of wear-resistant alloy powder:

[0066] The wear-resistant alloy powder comprises the following components: C: 1.5%, Cr: 30%, W: 7%, Co: 59%, Mo: 1.5%, and the balance is S element, and the sum of the masses of the components is 100%; the powder particle size is 25-45 μm.

[0067] (2) Strengthen the surface of wear-resistant steel belt:

[0068] S1. Use acetone to clean the surface of the wear-resistant steel belt of the sealed runway where the parts need to be strengthened, and remove oil, dust and other impurities;

[0069] S2. Sandblast the parts of the wear-resistant steel belt that need to be strengthened. The sandblasting sand is 80 mesh corundum sand, the sandblasting angle is 60°, and the sandblasting pressure is 0.50MPa;

[0070] S3, preheating the wear-resistant steel belt at a temperature of 150°C;

[0071] S4, spraying the wear-resistant alloy powder on the surface of the wear-resistant steel belt where reinforcement is required by supersonic flame spraying to form a wear-resistant coating, thereby completing the surface reinforcement of the wear-resistant steel belt;

[0072] Among them, the process parameters of supersonic flame spraying are: oxygen flow rate 800L / min, kerosene volume 20L / h, powder feeding volume 70g / min, and spraying distance 300mm.

[0073] Comparative Example 1

[0074] The difference between this comparative example and Example 3 is that the components of the prepared wear-resistant alloy powder are different, and the other aspects are exactly the same, and the surface strengthening process and process parameters are also exactly the same.

[0075] The wear-resistant alloy powder of this comparative example includes the following components: C: 0.5%, Cr: 31.0%, W: 6.0%, Co: 59.0%, Mo: 2.0%, and the balance is S element, and the sum of the masses of the components is 100%.

[0076] Comparative Example 2

[0077] The difference between this comparative example and Example 3 is that the components of the prepared wear-resistant alloy powder are different, and the other aspects are exactly the same, and the surface strengthening process and process parameters are also exactly the same.

[0078] The wear-resistant alloy powder of this comparative example includes the following components: C: 1.0%, Cr: 30.0%, W: 6.0%, Co: 60.0%, Mo: 1.8%, and the balance is S element, and the sum of the masses of the components is 100%.

[0079] Comparative Example 3

[0080] The difference between this comparative example and Example 3 is that the components of the prepared wear-resistant alloy powder are different, and the other aspects are exactly the same, and the surface strengthening process and process parameters are also exactly the same.

[0081] The wear-resistant alloy powder of this comparative example includes the following components: C: 1.2%, Cr: 30.0%, W: 3.0%, Co: 59.0%, Ni: 4.0%, Mo: 1.7%, and the balance is S element, and the sum of the masses of the components is 100%.

[0082] Test Example 1

[0083] This test example compares the performance effects of the surface-strengthened wear-resistant steel belts in Examples 1-3 and Comparative Examples 1-3, and respectively tests the hardness, surface roughness, porosity, and wear weight loss of the sealed runway wear-resistant steel belts sprayed by supersonic flame, and the measured performance data results are shown in Table 1. The test methods for the above performances are as follows:

[0084] Hardness: measured using a HVS-1000 microhardness tester with a loading load of 2.94N, a holding time of 10s, and measurement at 5 points.

[0085] Surface roughness: Measured using a TR200 surface roughness tester. Five areas were measured and the results were averaged.

[0086] Porosity: measured using an EM-30AX+ electron microscope, measuring 10 areas and taking the average value of the results of the 10 areas.

[0087] Wear weight loss: MLGS-225C dry and wet sand rubber wheel wear tester was used for measurement. The wear medium contained a large amount of hard abrasive garnet. The mass percentage of garnet was 30%. The load was 175N, the rotation speed was 200rmp, the wear time was 150min, and 5 samples were measured. The results were taken as the average of 5 times.

[0088] Table 1. Performance comparison of surface-reinforced wear-resistant steel belts in Examples 1-3 and Comparative Examples 1-3

[0089] Hardness (HV) Surface roughness(μm) Porosity Weight loss due to abrasion (mg) Example 1 1100-1300 Ra1.6 1.1％ 59 Example 2 700-900 Ra1.8 1.9％ 155 Example 3 500-700 Ra2.1 2.0％ 269 Comparative Example 1 400-600 Ra2.1 1.9％ 568 Comparative Example 2 400-600 Ra2.2 2.3％ 671 Comparative Example 3 400-600 Ra2.0 1.8％ 1021

[0090] The results of the examples and comparative examples in Table 1 show that when the composition and content of the wear-resistant alloy powder are not within the scope of protection of the present invention, the hardness of the material will be reduced, the weight loss due to wear will increase, and the wear performance will deteriorate.

[0091] Therefore, the present invention forms a wear-resistant coating prepared from alloy powder on the surface of the wear-resistant steel belt by reasonably selecting alloy powder components and optimizing the content of each component, and combines the processing technology of supersonic flame spraying to make the various elements cooperate with each other to obtain a wear-resistant steel belt with excellent wear resistance; further, through the interaction of structures such as bolts and expansion rings, the wear-resistant steel belt is fixed to the support ring, thereby realizing a sealed runway with excellent wear resistance and rapid installation and disassembly.

Claims

1. A wear-resistant alloy powder, wherein: The alloy powder comprises: C: 1.5%-5.0%, Cr: 0%-30.0%, W: 7%-80%, Co: 10%-59%, Mo: 0.6%-1.5%, and the remainder is S element, and the sum of the masses of the components is 100%.

2. The alloy powder according to claim 1, wherein The particle size of the alloy powder is 15-45 μm.

3. The alloy powder according to claim 1, wherein The alloy powder comprises: C: 3%-5%, Cr: 0%-10%, W: 30%-80%, Co: 10%-30%, Mo: 0.6%-1.2%, and the remainder is S element, and the sum of the masses of the various components is 100%.

4. A method for strengthening the surface of a wear-resistant steel belt, wherein: The surface strengthening method comprises: forming a wear-resistant coating on a portion of the wear-resistant steel belt surface that needs to be strengthened; The wear-resistant coating is prepared from the wear-resistant alloy powder according to any one of claims 1 to 3.

5. The surface strengthening method according to claim 4, wherein: The surface strengthening method comprises the following steps: S1. Clean the parts of the wear-resistant steel belt surface that need to be strengthened; S2, performing sandblasting on the surface of the wear-resistant steel belt obtained in S1 where the part that needs to be strengthened; S3, preheating the wear-resistant steel strip obtained in S2, with the preheating temperature being 150-250°C; S4. Using supersonic flame spraying, spray the wear-resistant alloy powder on the surface of the wear-resistant steel strip obtained in S3 where reinforcement is required to form a wear-resistant coating, thereby completing the surface reinforcement of the wear-resistant steel strip.

6. The surface strengthening method according to claim 5, wherein: The oxygen flow rate of the supersonic flame spraying is 720-800 L / min, the kerosene amount is 12-20 L / h, the powder feeding amount is 70-90 g / min, and the spraying distance is 200-300 mm.

7. The surface strengthening method according to claim 5, wherein: The sand particles used in the sand blasting are 60-80 mesh corundum sand, the sand blasting angle is 60-75°, and the sand blasting pressure is 0.40-0.50 MPa.

8. A wear-resistant steel belt, wherein: The wear-resistant steel belt is obtained by surface strengthening by the surface strengthening method described in any one of claims 4 to 7; the surface of the wear-resistant steel belt contains a wear-resistant coating.

9. The wear-resistant steel belt according to claim 8, wherein: The hardness of the wear-resistant steel belt is ≥500HV; the surface roughness of the wear-resistant steel belt is ≤Ra2.1μm; the coating porosity of the wear-resistant steel belt is ≤2.0%; the wear weight loss of the wear-resistant steel belt is ≤269mg; Preferably, the hardness of the wear-resistant steel belt is 500-1300 HV; the surface roughness of the wear-resistant steel belt is Ra1.6 μm to Ra2.1 μm; the coating porosity of the wear-resistant steel belt is 1.1%-2.0%; and the wear weight loss of the wear-resistant steel belt is 59-269 mg.

10. A main drive sealed runway for a tunnel boring machine, wherein: The sealed runway comprises a support ring, an expansion ring and the wear-resistant steel belt according to claim 8 or 9; The upper surface of the support ring is an inclined surface; the cross section of the expansion ring is a right triangle or a right trapezoid, which is located on the upper surface of the support ring; and the wear-resistant steel belt is located on the upper surface of the expansion ring.

11. The main drive sealed runway according to claim 10, wherein: The sealing runway comprises a support ring, a wear-resistant steel belt, an expansion ring and a pressure ring; The upper surface of the support ring is an inclined surface; the cross section of the expansion ring is a right triangle or a right trapezoid, which is located on the upper surface of the support ring; the wear-resistant steel belt is located on the upper surface of the expansion ring; The pressure ring is detachably arranged on the outer side surface of the support ring, and is fixed on the side surface of the support ring by bolts, and is tightly connected to the support ring. The bolts are provided with matching gaskets.

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