Repair alloy powder, paste material and in-hole repair method for main drive sealing runway of tunnel boring machine

Abstract

The invention provides repairing alloy powder, a pasty material and an in-hole repairing method for a main drive sealing runway of a tunnel boring machine. The repair alloy powder comprises Ni-based alloy powder, WC particles and diamond particles. The repairing alloy powder comprises, by mass, 0.7%-1.2% of C, 3.0%-5.5% of Si, 3.0%-5.5% of B, 10%-20% of Cr, 7%-10% of Fe, 5%-20% of WC particles, 5%-20% of diamond particles and the balance Ni, wherein the mass of the C, the Si, the B, the Cr, the Fe, the WC particles and the diamond particles is 100%. According to the repairing method, in-hole repairing is conducted on the abraded position of the sealing runway through the repairing method of first cold coating and then heating, the repairing speed is high, and the quality of the repaired surface is high. Compared with traditional surfacing repair, the sealed runway repaired through the method is lower in abrasion weight loss. In addition, dust pollution in the repairing process is avoided, the utilization rate of repairing powder is increased, and the polishing workload after repairing is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel construction equipment, and in particular relates to an in-tunnel repair method for repairing alloy powder, paste material and a main drive sealed runway of a tunnel boring machine. Background Art

[0002] The main drive seal system is one of the core systems of the tunnel boring machine. It helps prevent rock debris from entering the main bearing, thereby protecting the main bearing's safe service and increasing the service life of the equipment. However, the main drive seal runway will gradually undergo abrasive wear under the action of highly abrasive rock debris generated by the cutterhead breaking the rock. As the wear depth and width continue to increase, it will eventually lose its protective function. Therefore, the main drive seal runway needs to be inspected frequently and repaired when it is worn to a certain extent.

[0003] At present, the repair of the main drive sealed runway in the hole generally adopts the method of first surfacing welding and then grinding. However, the surfacing layer after surfacing welding is higher than the substrate and has a relatively high hardness. In addition, the method of surfacing welding and then grinding is very time-consuming and labor-intensive, requiring a lot of time, and there will be a lot of dust in the welding wire. It is the fine particles formed by the rapid condensation and oxidation of the vapor generated when the metal is molten in the air. It is difficult to avoid, and the ventilation in the tunnel is generally poor, which is harmful to the health of the operators, so the working environment is very poor.

[0004] Therefore, it is necessary to develop an in-hole repair material and method for the main drive sealed runway of a tunnel boring machine to achieve rapid repair and reduce the time required for repair. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a repair alloy powder, a paste material and a method for repairing the main drive sealed runway of a tunnel boring machine. The specific repair alloy powder is used for the repair of the worn position of the sealed runway in the hole, which can solve the time-consuming and labor-intensive problems in the repair technology.

[0006] To achieve the above-mentioned purpose, the present invention provides a repair alloy powder, wherein the repair alloy powder comprises: Ni-based alloy powder, WC particles and diamond particles; taking the sum of the mass of the repair alloy powder as 100%, the proportion of each component is C 0.7%-1.2%, Si 3.0%-5.5%, B 3.0%-5.5% (preferably 3.0%-4.5%), Cr10%-20%, Fe 7%-10%, WC particles 5%-20%, diamond particles 5%-20%, and the remainder is Ni.

[0007] The inventors of the present invention have found that the repair alloy powder can provide the strength, impact resistance and wear resistance required for the worn runway. The various components in the alloy can play a synergistic role, as follows:

[0008] C: can form carbides with Cr to improve wear resistance;

[0009] B. Si: It can preferentially react with the oxides in the matrix when heated at high temperature to generate low-melting-point borosilicate and other substances, and has deoxidation and slag-forming capabilities; in addition, it can reduce the melting point of the alloy powder;

[0010] Cr: It can improve the strength and plasticity of the coating. Cr and Ni precipitate NiCr solid solution to improve the strength of the coating. Cr forms carbides and borides with C and B to improve the hardness and wear resistance of the coating. In addition, since the Cr element is magnetic, the Cr content in the alloy powder should not be too high to avoid greater fluidity of the molten coating when heated.

[0011] Fe: Its thermal expansion coefficient is close to that of the matrix and its cost is low;

[0012] Ni: can be used as a binder phase, has high toughness and can reduce brittleness; Ni-based alloy powder has good wettability, deoxidation and slag-forming ability, and its melting point is between 900-1200℃, which is easy to achieve;

[0013] WC particles: have high hardness and good wear resistance; WC particles are used together with Ni-based alloy powder to improve the wetting effect between alloy powder and hard particles, thus making the metallurgical bonding stronger;

[0014] Diamond particles: have the functions of wear resistance, friction reduction and friction coefficient reduction. They can hinder the movement of abrasive particles during abrasive wear, thereby significantly improving wear resistance and service life.

[0015] According to a specific embodiment of the present invention, preferably, the particle size of the diamond particles is 53-165 μm, the particle size of the WC particles is 15-45 μm, and the particle size of the remaining Ni-based alloy powder is 25-35 μm.

[0016] The present invention also provides a paste material, wherein the paste material comprises an additive, a binder and the above-mentioned repair alloy powder;

[0017] According to a specific embodiment of the present invention, preferably, based on the mass of the repaired alloy powder as 100%, the content of the auxiliary agent is 3-5%, and the content of the binder is 7-10%; the calculation basis based on the mass of the repaired alloy powder as 100% does not include auxiliary agents and binders. The inventors of the present invention have found that adding auxiliary agents can reduce the melting point of the alloy, reduce the surface energy of the metal particles, improve the wettability of the metal solution to the reinforcing phase and the substrate, and improve the bonding strength of the coating, but excessive addition is prone to form slag inclusions; the binder can bond the alloy powder particles and can volatilize during the preparation process, so it basically does not affect the performance of the coating; too little binder, the powder is too loose, and the powder cannot be guaranteed to be firmly attached to the surface of the substrate, but excessive addition is prone to form an overly thick coating layer on the surface of the metal particles, affecting the contact reaction between the metal particles, causing defects such as slag inclusions and voids.

[0018] According to a specific embodiment of the present invention, preferably, the paste material is prepared by mixing the repair alloy powder after ball milling with an additive and a binder.

[0019] In some specific embodiments, preferably, the ball milling time is 4-10 hours, and the ball milling speed is 200-400 r / min.

[0020] According to a specific embodiment of the present invention, preferably, the auxiliary agent is calcium fluoride and / or sodium fluoride.

[0021] According to a specific embodiment of the present invention, preferably, the binder is a saturated aqueous solution of Na2SiO3.

[0022] The present invention also provides a method for repairing a main drive sealed runway of a tunnel boring machine in a tunnel, wherein the method comprises:

[0023] (1) cold-coating the above-mentioned paste material on the worn and cleaned runway surface, with the coating height being flush with the unworn runway surface;

[0024] (2) drying the cold-coated paste material on the runway and further heating it;

[0025] (3) Grind the heated runway surface to complete the hole repair.

[0026] In the present invention, a process of cold coating - drying - flame heating - polishing of a paste material containing repair alloy powder is adopted, which can greatly shorten the time required for repair. In addition, the method of first mixing the alloy powder into a paste, then cold coating it on the worn runway surface and heating it can reduce dust pollution.

[0027] In the above repair method, preferably, the temperature of the cold coating is 20-40° C. The cold coating temperature for repairing outside the hole is generally room temperature, while the cold coating temperature for repairing inside the hole is generally higher, and 20-40° C. meets the use requirements.

[0028] In the above repair method, preferably, the heating method includes flame heating and / or induction heating.

[0029] In the above repair method, preferably, the temperature of the flame heating is 1100-1250°C, and the heating time is 0.5-10 minutes. In the present invention, high-temperature flame heating can make the molten alloy powder form a metallurgical bond with the runway after solidification, thereby generating a higher bonding force. If the temperature is low, metallurgical bonding cannot be formed, resulting in a decrease in the bonding force between the repaired alloy powder and the substrate; in addition, residual compressive stress exists on the surface of the runway after flame heating, which helps to improve the surface wear resistance.

[0030] In some specific embodiments, preferably, the oxygen flow rate of the flame heating is 3-8 L / min, and the distance between the flame and the sample surface is 4-10 mm.

[0031] In the above repair method, preferably, the induction power of the induction heating is 40-80 kW, the frequency is 6-10 kHz, and the moving speed of the induction coil is 30-50 mm / min.

[0032] In some specific embodiments, preferably, the drying temperature is 80-150° C., and the drying time is 3-5 h.

[0033] In the present invention, there is no limitation on the material of the main drive sealing runway to be repaired, and it can be applicable to the repair of steel materials or chemical alloy materials. For example, the chemical composition of the sealing runway is: in weight percentage, C 0.38%-0.45%, Si 0.17%-0.37%, Mn 0.5%-0.8%, Cr 0.9%-1.2%, Mo 0.15%-0.25%, and the rest is Fe.

[0034] In some specific embodiments, preferably, the cleaning process is: cleaning the worn main drive seal track, removing impurities such as surface oil stains, and polishing the surface to reveal a metallic luster.

[0035] According to a specific embodiment of the present invention, preferably, the time taken to repair a runway with a diameter of 7 m using the in-hole repair method is 5-10 days.

[0036] The present invention further provides a tunnel boring machine main drive sealed runway, which is repaired by the above-mentioned in-hole repair method.

[0037] According to a specific embodiment of the present invention, preferably, the hardness of the main drive seal track is ≥998HV, and the wear weight loss of the main drive seal track after wear is ≤0.98g. The wear condition is: wear for 10 hours under laboratory accelerated test conditions, with a rotation speed of 200r / min.

[0038] According to a specific embodiment of the present invention, preferably, the hardness of the main drive seal track is 998-1108 HV, and the wear weight loss of the main drive seal track after wear is 0.34-0.98 g. The wear conditions are: wear for 10 hours under laboratory accelerated test conditions, and the rotation speed is 200 r / min.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The repair alloy powder provided by the present invention is added with diamond particles. Combined with the shorter heating time in the repair method, the diamond in the alloy powder of the present invention does not ablate at high temperature, thereby significantly improving the wear resistance and life. In addition, the repair alloy powder used in the present invention is Ni-based powder, which has a lower cost.

[0041] (2) The present invention adopts a repair method of first cold coating and then heating to repair the worn position of the main drive seal runway in the hole, with a fast repair speed and high repair surface quality. In addition, the repair method can directly repair the main drive seal runway in situ in the hole, greatly shortening the time required for repair.

[0042] (3) Compared with the traditional cladding repair, the seal runway repaired by the present invention has lower wear weight loss, can achieve high-quality repair of the worn runway surface, and has a short repair time. Moreover, the repaired surface has high wear resistance and is not prone to re-wear. In addition, dust pollution during the repair process is avoided, the utilization rate of the repair powder is improved, and the grinding workload after the repair is reduced. DETAILED DESCRIPTION

[0043] 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.

[0044] The chemical composition of the main drive seal runway repaired in the following Examples 1-3 and Comparative Examples 3-4 is as follows: by weight percentage, C: 0.43%, Si: 0.25%, Mn: 0.65%, Cr: 1.1%, Mo: 0.20%, and the rest is Fe. The material of the main drive seal runway repaired in Comparative Example 1-2 is 42CrMo, and the standard is GB / T 3077-2015.

[0045] Example 1

[0046] This embodiment provides a repair alloy powder, which includes: C 0.7%, Si 3.0%, B 5.5%, Cr 10%, Fe 7%, WC particles 5%, diamond particles 20%, and the rest is Ni, with the total mass of the repair alloy powder being 100%. The diamond particles have a particle size of 53-165 μm, the WC particles have a particle size of 15-45 μm, and the remaining Ni-based alloy powder has a particle size of 25-35 μm. The diamond particles, WC particles, and the remaining Ni-based alloy powder are uniformly mixed to obtain the repair alloy powder.

[0047] This embodiment further provides a method for repairing a main drive sealed runway of a tunnel boring machine in a tunnel, and the specific process is as follows:

[0048] Step 1: Clean the worn main drive seal runway, remove impurities such as oil on the surface, and polish the surface to reveal the metallic luster.

[0049] Step 2: ball mill the above repair alloy powder at a speed of 300r / min for 5h, then mix it evenly with the additive and adhesive to make a paste material. Taking the mass of the repair alloy powder as 100%, the content of the additive is 3%, and the content of the adhesive is 7%. Among them, the additives are calcium fluoride and sodium fluoride, and the mass ratio of calcium fluoride to sodium fluoride is 2:1; the adhesive is a saturated aqueous solution of Na2SiO3.

[0050] Step 3: At room temperature in the hole, cold-apply the paste material to the worn surface of the runway to a height that is flush with the unworn surface of the runway.

[0051] Step 4: Drying the cold-coated paste material on the runway, wherein the drying temperature is 100° C. and the drying time is 4 hours.

[0052] Step 5: Use a spray gun to flame heat the dried material, where the heating temperature is 1100°C, the heating time is 10 min, the oxygen flow rate is 4 L / min, and the distance between the flame and the sample surface is 4 mm.

[0053] Step 6: Grind the flame-heated runway surface to complete the repair.

[0054] Example 2

[0055] This embodiment provides a repair alloy powder, which includes: C 1.2%, Si 5.5%, B 3.0%, Cr 20%, Fe 10%, WC particles 20%, diamond particles 15%, and the rest is Ni, with the total mass of the repair alloy powder being 100%. The diamond particles have a particle size of 53-165 μm, the WC particles have a particle size of 15-45 μm, and the rest of the Ni-based alloy powder has a particle size of 25-35 μm. The diamond particles, WC particles, and the rest of the alloy powder are mixed evenly to obtain the repair alloy powder.

[0056] This embodiment further provides a method for repairing a main drive sealed runway of a tunnel boring machine in a tunnel, and the specific process is as follows:

[0057] Step 1: Clean the worn main drive seal runway, remove impurities such as oil on the surface, and polish the surface to reveal the metallic luster.

[0058] Step 2: Ball mill the above repair alloy powder at a speed of 400r / min for 4h, then mix it evenly with the additive and adhesive to make a paste material. Taking the mass of the repair alloy powder as 100%, the content of the additive is 5%, and the content of the adhesive is 8%. Among them, the additives are calcium fluoride and sodium fluoride, and the mass ratio of calcium fluoride to sodium fluoride is 2:1; the adhesive is a saturated aqueous solution of Na2SiO3.

[0059] Step 3: At room temperature in the hole, cold-apply the paste material to the worn surface of the runway to a height that is flush with the unworn surface of the runway.

[0060] Step 4: Dry the cold-coated paste material on the runway at a temperature of 80°C and a drying time of 5 hours.

[0061] Step 5: Use a spray gun to flame heat the dried material. The heating temperature is 1180℃, the heating time is 3min, the oxygen flow rate is 3L / min, and the distance between the flame and the sample surface is 10mm.

[0062] Step 6: Grind the flame-heated runway surface.

[0063] Example 3

[0064] This embodiment provides a repair alloy powder. Taking the sum of the mass of the repair alloy powder as 100%, the repair alloy powder includes: C 0.9%, Si 4.6%, B 4%, Cr 15%, Fe 8%, WC particles 13%, diamond particles 5%, and the rest is Ni. The particle size of the diamond particles is 53-165 μm, the particle size of the WC particles is 15-45 μm, and the particle size of the remaining Ni-based alloy powder is 25-35 μm. The diamond particles, WC particles and the remaining alloy powder are mixed evenly to obtain the repair alloy powder.

[0065] This embodiment further provides a method for repairing a main drive sealed runway of a tunnel boring machine in a tunnel, and the specific process is as follows:

[0066] Step 1: Clean the worn main drive seal runway, remove impurities such as oil on the surface, and polish the surface to reveal the metallic luster.

[0067] Step 2: Ball mill the above repair alloy powder at a speed of 200r / min for 10h, then mix it with the additive and adhesive to make a paste material. Taking the mass of the repair alloy powder as 100%, the content of the additive is 4.5%, and the content of the adhesive is 10%. Among them, the additives are calcium fluoride and sodium fluoride, and the mass ratio of calcium fluoride to sodium fluoride is 2:1; the adhesive is a saturated aqueous solution of Na2SiO3.

[0068] Step 3: At room temperature in the hole, cold-apply the paste material to the worn surface of the runway to a height that is flush with the unworn surface of the runway.

[0069] Step 4: Dry the cold-coated paste material on the runway at a drying temperature of 150°C and a drying time of 3 hours.

[0070] Step 5: Use a spray gun to flame heat the dried material. The heating temperature is 1250℃, the heating time is 0.5min, the oxygen flow rate is 8L / min, and the distance between the flame and the sample surface is 6mm.

[0071] Step 6: Grind the flame-heated runway surface.

[0072] Comparative Example 1

[0073] This comparative example provides a method for repairing a main drive sealed runway of a tunnel boring machine, and uses a surface quenching method to repair a sealed runway made of 42CrMo. The specific process is as follows:

[0074] The worn parts of the sealed runway are surface hardened, and the hardness after surface quenching is 598HV.

[0075] Comparative Example 2

[0076] This comparative example provides a method for repairing a main drive sealed runway of a tunnel boring machine, using a surfacing repair method to repair a sealed runway made of 42CrMo. The specific process is as follows:

[0077] The hardness of the sealed runway before repair was 55HRC. The worn parts of the sealed runway were repaired with welding wire, and the welding wire was HF-63T flux-cored welding wire. The hardness after repair was 540HV.

[0078] Comparative Example 3

[0079] This comparative example provides a method for repairing a main drive sealed runway of a tunnel boring machine in a tunnel. The repair method is basically the same as that of Example 1, except that the content of the auxiliary agent in step 2 is 2% and the content of the binder is 5%.

[0080] Comparative Example 4

[0081] This comparative example provides a method for repairing a main drive sealed runway of a tunnel boring machine in a tunnel. The repair method is basically the same as Example 1, except that the flame heating temperature in step five is 1000° C. and the heating time is 20 seconds.

[0082] Test Example 1

[0083] This test example provides a comparison of the effects of the repair methods in Examples 1-3 and Comparative Examples 1-4, and compares the wear resistance of the coating layer. The specific test method is as follows:

[0084] Samples of the same size in Examples 1-3 and Comparative Examples 1-4 were respectively selected for wet sand wear tests, wherein the wear test object was nitrile rubber commonly used in tunnel boring machine seals, with a Shore hardness of 80 and a nitrile rubber sample diameter of 178 mm. The load was 200 N, the rotation speed was 200 r / min, and the wear test time was 10 h.

[0085] The hardness was measured by a Vickers hardness tester, the substrate hardness was tested before wear, and the wear weight loss was tested after the wear test. At the same time, the cracking of the coating layer was observed before and after the test.

[0086] The above results are shown in Table 1.

[0087] Table 1. Wear test results of Examples 1-3 and Comparative Examples 1-4

[0088] Hardness, HV Wear loss, g Coating cracking Example 1 1108 0.34 no Example 2 1056 0.45 no Example 3 998 0.98 no Comparative Example 1 598 3.06 - Comparative Example 2 540 4.58 no Comparative Example 3 1089 - yes Comparative Example 4 1010 1.24 no

[0089] It can be seen from Table 1 that the wear weight loss of Examples 1-3 of the present invention is significantly lower than that of the surface-quenched 42CrMo steel and the 42CrMo steel surfacing layer after surfacing welding repair. It can be seen that the in-hole repair method provided by the present invention improves the wear resistance of the main drive sealed runway of the tunnel boring machine, and still has a low wear weight loss after long-term wear for 10 hours, which is helpful to increase the service life of the sealed runway.

[0090] In addition, Examples 1-3 have a shorter repair time. Taking a runway with a diameter of 7 m as an example, the traditional repair method in Comparative Example 2 requires 30 days, while Examples 1-3 only require 10 days, shortening the repair time by 67%.

Claims

1. A repair alloy powder, wherein: The repair alloy powder comprises: Ni-based alloy powder, WC particles and diamond particles; Taking the total mass of the repair alloy powder as 100%, the proportion of each component is C 0.7%-1.2%, Si 3.0%-5.5%, B 3.0%-5.5%, Cr 10%-20%, Fe 7%-10%, WC particles 5%-20%, diamond particles 5%-20%, and the remainder is Ni.

2. The repair alloy powder according to claim 1, wherein: The particle size of the diamond particles is 53-165 μm, the particle size of the WC particles is 15-45 μm, and the particle size of the remaining Ni-based alloy powder is 25-35 μm.

3. A paste material, wherein: The paste material comprises an additive, a binder and the repair alloy powder according to claim 1 or 2; Taking the mass of the repair alloy powder as 100%, the content of the auxiliary agent is 3-5%, and the content of the binder is 7-10%; Preferably, the paste material is prepared by mixing the repair alloy powder after ball milling with an additive and a binder.

4. The paste material according to claim 3, wherein: The auxiliary agent is calcium fluoride and / or sodium fluoride.

5. The paste material according to claim 3, wherein: The binder is a saturated aqueous solution of Na2SiO3.

6. A method for repairing a tunnel boring machine main drive sealed runway in a tunnel, wherein: The hole repair method includes: (1) cold-coating the paste material according to any one of claims 3 to 5 on the surface of a runway that has been cleaned after wear, with the coating height being flush with the surface of the runway that has not been worn; (2) drying the cold-coated paste material on the runway and further heating it; (3) Grind the heated runway surface to complete the hole repair.

7. The hole repair method according to claim 6, wherein: The temperature of the cold coating is 20-40°C.

8. The hole repair method according to claim 6, wherein: The heating method includes flame heating and / or induction heating; Preferably, the flame heating temperature is 1100-1250°C, and the heating time is 0.5-10min; Preferably, the induction power of the induction heating is 40-80 kW, the frequency is 6-10 kHz, and the moving speed of the induction coil is 30-50 mm / min.

9. The hole repair method according to claim 6, wherein: The time taken to repair a runway with a diameter of 7 m using the in-hole repair method is 5-10 days.

10. A tunnel boring machine main drive sealed runway, which is repaired by the in-hole repair method according to any one of claims 6 to 9; Preferably, the hardness of the main drive seal runway is ≥998HV, and the wear weight loss of the main drive seal runway after wear is ≤0.98g; Preferably, the hardness of the main drive sealing track is 998-1108 HV, and the wear weight loss of the main drive sealing track after wear is 0.34-0.98 g.