CN110468406B - Wear-resistant coating and preparation method thereof, cutter ring of shield hob, shield hob and shield machine - Google Patents

Abstract

The invention provides a wear-resistant coating and a preparation method thereof, a cutter ring of a shield hob, the shield hob and a shield machine, wherein the wear-resistant coating comprises at least two layers of brazing filler metal coatings which are basically the same; the brazing filler metal coating is prepared from the following components in parts by mass: 3-10 parts of diamond micro powder, 2-6 parts of alcohol solvent, 1-5 parts of sodium fluoride and 81-93 parts of nickel-based brazing filler metal. The wear-resistant coating provided by the invention adopts a multi-pass, basically same and thin coating to form a gradient transition coating, relieves the problem of thermal stress when a thick coating is prepared by a surfacing method, inhibits the initiation and the expansion of cracks to a certain extent, is also beneficial to improving the uniform distribution degree of hard phase diamond micro powder, and has the advantages of small thermal damage, uniform hard phase distribution and difficult shedding. According to the shield hobbing cutter provided by the invention, the wear-resistant coating is coated on the surface of the cutter ring, so that the wear resistance of the cutter ring is effectively improved, and the service life of the cutter ring is prolonged.

Description

Wear-resistant coating and preparation method thereof, cutter ring of shield hob, shield hob and shield machine

technical field

The invention relates to the field of surface treatment of engineering equipment, in particular to a wear-resistant coating and a preparation method thereof, a cutter ring of a shield hob, a shield hob and a shield machine.

Background technique

Shield hob is a kind of shield machine tool, which plays the role of advancing "forward" in construction. The shield hob consists of a cutter ring and a cutter tooth. The cutter ring is generally made of alloy steel as the base material, and the cutter teeth are brazed or inlaid carbide. Carbide teeth play the role of rolling and cutting rock and soil, and the cutter ring supports and protects the carbide teeth. Affected by the random changes of soil conditions and groundwater pressure, with the continuous advancement of construction and the continuous rotation of the cutter head, the shield hob is subjected to continuous and changing forces such as extrusion, jacking, scraping, impact, and wear. way, mainly for the strong wear and impact of the tool.

Both the hob ring and the carbide teeth are subject to rock wear. Since the rock-breaking efficiency of the hob is related to the width of the cutting edge of the hob, with the increase of the wear of the cutter ring, the width of the cutting edge increases. When it reaches a certain range, the driving speed will be affected, and even no further driving will be possible. Therefore, the failure mode of the hob is mainly the wear of the cutter ring and the fracture of the cutter ring. Among them, the wear resistance of the rolling cutter ring is the key to the failure of the hob. In order to improve the wear resistance of the hob ring and prevent micro-cracks when brazing or inlaid with cemented carbide, domestic and foreign research institutes and factories often use high-strength alloy steel as the material of the hob ring, which is forged to form and surface. Carburizing and quenching to improve wear resistance. However, the cutter ring around the tooth heel is still not very hard, and the carburizing depth is not very deep. The rock can easily grind off the carburized layer, which limits the life of the cutter ring. Therefore, it is of great significance to use surface technology to prepare wear-resistant coatings on the surface of shield hob cutter rings.

However, the existing shield hob cutter ring coating has the following problems: the wear-resistant coating of the cutter ring is prepared by the surfacing method, although a thicker coating can be prepared, but the heat output of surfacing welding is large, and the thermal stress after surfacing welding is large , it is easy to produce cracks, it is easy to expand into the base metal, and the cutter ring is broken; at present, the commonly used hard phases of coatings are mostly large-grained carbides or cemented carbides, and the coatings are uneven, which is prone to local stress concentration, resulting in micro Cracks, which cause the hard phase of large particles to easily break or fall off during the working process; the conventional brazing method is used to prepare the wear-resistant coating. Although the thermal stress is small, the prepared coating is very thin, and the hard phase in the coating is uniform. The degree of cloth is low, and the wear resistance of the cutter ring is difficult to effectively improve.

In view of this, the present invention is proposed.

SUMMARY OF THE INVENTION

The first object of the present invention is to provide a wear-resistant coating to solve the above-mentioned problems completely or partially. , alleviates the thermal stress problem when preparing thicker coatings by surfacing method, inhibits the initiation and expansion of cracks to a certain extent, and also helps to improve the uniform distribution of hard phase diamond powder, with less thermal damage and hard phase The advantages of uniform distribution and not easy to fall off.

The second object of the present invention is to provide a method for preparing the wear-resistant coating, which uses a laser spot as a heat source, has the advantages of fast heating rate, small heat-affected zone of the base material and diamond, etc., and will not cause excessive heat. Large thermal damage, no heat treatment is required after coating preparation, and the integration of coating preparation and heat treatment is realized.

Another object of the present invention is to provide a shield hob, the surface of the blade ring of the shield hob is coated with the wear-resistant coating, which effectively improves the wear resistance of the blade ring and prolongs the life of the blade ring. service life.

In order to realize the above-mentioned purpose of the present invention, the following technical solutions are specially adopted:

A wear-resistant coating comprising at least two layers of substantially identical brazing filler metal coatings;

The solder coating is prepared by including the following components in parts by mass:

3-10 parts of diamond micropowder, 2-6 parts of alcohol solvent, 1-5 parts of sodium fluoride and 81-93 parts of nickel-based brazing filler metal.

Preferably, the coating thickness of the solder coating is 0.5-0.7 mm.

Preferably, the solder coating is prepared by including the following components in parts by mass:

5-8 parts of diamond micropowder, 3-5 parts of alcohol solvent, 1-3 parts of sodium fluoride and 80-90 parts of nickel-based brazing filler metal.

Preferably, the nickel-based solder is BNi-2.

Preferably, the alcohol solvent is selected from C8-10 alcohol solvents, and more preferably, the alcohol solvent is selected from terpineol.

The preparation method of the wear-resistant coating provided by the present invention comprises the following steps:

(a) Coating the brazing filler metal mixture of diamond micropowder, alcohol solvent, sodium fluoride and nickel-based brazing filler metal on the surface of the substrate, drying the brazing filler metal mixture to make it lose moisture, using a laser under the condition of protective gas Scan the dried brazing filler metal mixture, after the brazing filler metal is melted and spread, metallurgical bonding with the substrate is achieved to obtain a brazing filler metal coating;

Preferably, the particle size of the diamond micropowder is 200-325 mesh, more preferably 230-270 mesh;

Preferably, the nickel-based brazing filler metal is a powder material, and the particle size of the powder material is 200-300 mesh, more preferably 230-270 mesh;

(b) Optionally repeat step (a) until a desired thickness of the abrasion resistant coating is obtained.

Preferably, in step (a), the laser uses a CO ₂ laser spot as a heat source;

More preferably, the diameter of the laser spot is 12-15 mm, and the scanning speed is 200-380 mm/min;

More preferably, the protective gas is argon.

Preferably, in step (a), the drying is drying, and the drying temperature is 85-100° C., more preferably, the drying time is 1.5-2 h.

A cutter ring of a shield hob, the surface of which is coated with the wear-resistant coating, preferably, the thickness of the wear-resistant coating is 5-6 mm.

A shield hob includes the blade ring of the shield hob.

A shield machine includes the shield hob.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The wear-resistant coating provided by the present invention adopts multi-pass, basically the same, thinner coating to form a gradient transition coating, which relieves the thermal stress when the thick coating is prepared by the surfacing method To a certain extent, it can inhibit the initiation and expansion of cracks, and it also helps to improve the uniform distribution of the hard phase diamond powder, which has the advantages of small thermal damage, uniform distribution of the hard phase and not easy to fall off.

(2) The preparation method of a wear-resistant coating provided by the present invention uses a laser spot as a heat source, which has the advantages of fast heating rate, small heat-affected zone of base material and diamond, etc., and will not cause excessive thermal damage, After the coating is prepared, no heat treatment is required, and the integration of coating preparation and heat treatment is realized.

(3) In the shield hob provided by the present invention, the surface of the cutter ring is coated with the wear-resistant coating, which effectively improves the wear resistance of the cutter ring and prolongs the service life of the cutter ring.

Description of drawings

In order to illustrate the specific embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the specific embodiments or the prior art. Obviously, the accompanying drawings in the following description The drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

Fig. 1 is the structural representation of the wear-resistant coating provided by the present invention;

FIG. 2 is a schematic structural diagram of the grinding coating of the shield hob provided by the present invention.

Description of drawings:

1- Wear-resistant coating; 2- Brazing material coating; 3- Shield hob cutter ring.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments, but those skilled in the art will understand that the embodiments described below are part of the embodiments of the present invention, rather than all of the embodiments, It is only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market.

A wear-resistant coating 1 provided by the present invention, the wear-resistant coating 1 includes at least two layers of substantially the same brazing filler metal coating 2;

The wear-resistant coating 1 provided by the present invention adopts multi-pass, basically the same, thinner coating to form a gradient transition coating, which alleviates the thermal stress problem when the thick coating is prepared by the surfacing method. It inhibits the initiation and expansion of cracks to a certain extent, and also helps to improve the uniform distribution of the hard phase diamond micropowder, which has the advantages of less thermal damage, uniform distribution of the hard phase and not easy to fall off.

The solder coating 2 is prepared by including the following components in parts by mass:

3-10 parts of diamond powder (such as 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts), 2-6 parts of alcohol solvent (such as 2 parts, 3 parts, 4 parts) , 5 parts, 6 parts), 1-5 parts of sodium fluoride (such as 1 part, 2 parts, 3 parts, 4 parts, 5 parts) and 81-93 parts of nickel-based solder (such as 81 parts, 82 parts, 83 parts) 84, 85, 86, 87, 88, 90, 91, 92, 93).

Among them, the diamond fine powder includes single crystal diamond fine powder and polycrystalline diamond fine powder. Due to the large output of single crystal diamond micropowder and wide application fields, diamond micropowder is generally referred to as single crystal diamond micropowder in the industry. The material is produced by a special process method. Diamond micropowder has high hardness and good wear resistance, and can be widely used in cutting, grinding, drilling, polishing, etc. The diamond micropowder is added as a hard phase in the nickel-based solder, which has the advantages of small thermal damage, uniform distribution of the hard phase, and low cost. Sodium fluoride plays a role in fluxing. Alcohol solvents can make the components well combined, which is conducive to coating on the surface of the substrate.

In some preferred embodiments of the present invention, the coating thickness of each layer of the solder coating 2 is controlled to be 0.5-0.7 mm, so as to improve the bonding force between the coating and the substrate and each layer of the solder coating 2 .

In some preferred embodiments of the present invention, the raw material of the brazing filler metal coating 2 can be further optimized, and is prepared by including the following components in parts by mass:

5-12 parts of diamond micropowder, 3-5 parts of alcohol solvent, 1-3 parts of sodium fluoride and 79-95 parts of nickel-based brazing filler metal.

In some preferred embodiments of the present invention, the nickel-based solder is BNi-2 solder powder.

The nickel-based solder includes Ni60, Ni60M, Ni62, Ni45, BNi-2 and other nickel-based alloy powders. In this application, it is preferably BNi-2 (BNi ₈₂ CrSiB) solder alloy powder, with a melting point of 970°C-1000°C, with high purity , less impurities, good fluidity, low oxygen content and so on. Brazing solder for high temperature and dynamic loads, for structural parts in the field of engine blades and steel mills. It can be used for brazing of iron-based, nickel-based, cobalt-based and special materials.

In some preferred embodiments of the present invention, the alcohol solvent is selected from C8-10 alcohol solvents, and further, terpineol is used to prepare solder powder into solder paste.

The preparation method of the wear-resistant coating 1 provided by the present invention comprises the following steps:

(a) Coating the brazing filler metal mixture of diamond micropowder, alcohol solvent, sodium fluoride and nickel-based brazing filler metal on the surface of the substrate, drying the brazing filler metal mixture to make it lose moisture, using a laser under the condition of protective gas Scanning the dried brazing filler metal mixture, after the brazing filler metal is melted and spread, metallurgical bonding with the substrate is achieved to obtain the brazing filler metal coating 2;

(b) Optionally repeat step (a), as shown in Figure 1, until a desired thickness of the wear resistant coating 1 is obtained.

The preparation method of the wear-resistant coating 1 provided by the present invention uses a laser spot as a heat source, has the advantages of fast heating rate, small heat-affected zone of the base material and diamond, etc., will not cause excessive thermal damage, and the coating No heat treatment is required after preparation, and the integration of coating preparation and heat treatment is realized.

Particle size refers to the size of the particles. Generally, the particle size of spherical particles is expressed by diameter, and the particle size of cubic particles is expressed by side length. In some preferred embodiments of the present invention, the particle size of the diamond micropowder is preferably 200-325 mesh, more preferably 230-270 mesh, so that the diamond micropowder has good dispersibility in the coating.

In some preferred embodiments of the present invention, the particle size of the nickel-based solder is 200-300 mesh, more preferably 230-270 mesh, and the nickel-based solder under this mesh size has a good matching effect with the diamond micropowder, Make the raw materials evenly dispersed.

In some preferred embodiments of the present invention, in step (a), the laser uses a CO ₂ laser spot as a heat source;

More preferably, the diameter of the laser spot is 12-15 mm, and the scanning speed is 200-380 mm/min, so that the brazing material can be rapidly melted and spread, and the generation of cracks can be reduced.

In some preferred embodiments of the present invention, the protective gas is argon.

In some preferred embodiments of the present invention, in step (a), the drying is drying, and the drying temperature is 85-100° C. More preferably, the drying time is 1.5-2 hours .

A cutter ring of a shield hob, as shown in Figure 2, is coated with the wear-resistant coating 1 on its surface, preferably, the thickness of the wear-resistant coating 1 is 5-6 mm.

In the shield hob provided by the present invention, the surface of the cutter ring is coated with the wear-resistant coating 1, and the thickness of the coating can reach 5-6 mm, which effectively improves the wear resistance of the cutter ring and prolongs the cutting cycle. the service life of the circle.

A shield hob includes the blade ring of the shield hob.

A shield machine includes the shield hob.

The embodiments of the present invention will be described in detail below with reference to the examples, but those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be obtained from the market.

Example 1

The preparation method of the wear-resistant coating 1 provided by this embodiment specifically includes the following steps:

A. Calculated by mass fraction, weigh 3 parts of diamond micropowder (200-325 mesh), 3 parts of terpineol, 1 part of sodium fluoride and 93 parts of BNi-2 solder powder (200-300 mesh), mix thoroughly , stirring to prepare a paste solder mixture for use;

B. Coat the paste brazing material mixture evenly on the working surface of shield hob cutter ring 3, control the thickness to 0.7mm, after cooling and drying, put it in a drying box, dry it at 100 ℃ for 1.5h, and dry it for coating moisture inside the layer;

C. Fix the dried shield hob cutter ring 3 on the high temperature resistant bracket, supplemented by argon as the protective gas, with a CO ₂ laser spot with a diameter of 15mm as the heat source, and the scanning speed is 380mm/min. The dried brazing filler metal mixture melts and spreads the coating brazing filler metal, and realizes metallurgical bonding with the base of the shield hob cutter ring 3 to obtain the brazing filler metal coating 2;

D. On the surface of the brazing filler metal coating 2 obtained in step C, repeat steps B and C until the coating thickness reaches 6 mm, that is, a gradient wear-resistant coating 1 is obtained on the surface of the shield hob cutter ring 3 .

Example 2

The preparation method of the wear-resistant coating 1 provided by this embodiment specifically includes the following steps:

A. Calculated in parts by mass, weigh 4 parts of diamond micropowder (200-325 mesh), 4 parts of terpineol, 2 parts of sodium fluoride and 90 parts of BNi-2 solder powder (200-300 mesh), mix thoroughly , stirring to prepare a paste solder mixture for use;

B. Coat the paste brazing material mixture evenly on the working surface of the shield hob cutter ring 3, control the thickness to 0.6mm, after cooling and drying, put it in a drying box, dry it at 90 ℃ for 1.5h, dry and coat moisture inside the layer;

C. Fix the dried shield hob cutter ring 3 on the high temperature resistant bracket, supplemented by argon as the protective gas, with a CO ₂ laser spot with a diameter of 13mm as the heat source, and the scanning speed is 230mm/min. The dried brazing filler metal mixture melts and spreads the coating brazing filler metal, and realizes metallurgical bonding with the base of the shield hob cutter ring 3 to obtain the brazing filler metal coating 2;

D. On the surface of the brazing filler metal coating 2 obtained in step C, repeat steps B and C until the coating thickness reaches 6 mm, that is, a gradient wear-resistant coating 1 is obtained on the surface of the shield hob cutter ring 3 .

Example 3

The preparation method of the wear-resistant coating 1 provided by this embodiment specifically includes the following steps:

A. Calculated in parts by mass, weigh 5 parts of diamond micropowder (230-270 mesh), 5 parts of terpineol, 3 parts of sodium fluoride and 87 parts of BNi-2 solder powder (200-300 mesh), mix thoroughly , stirring to prepare a paste solder mixture for use;

B. Coat the paste solder mixture evenly on the working surface of the shield hob cutter ring 3, control the thickness to 0.5mm, after cooling and drying, put it in a drying box, dry it at 85 ℃ for 2 hours, and dry the coating internal moisture;

C. Fix the dried shield hob cutter ring 3 on the high temperature resistant bracket, supplemented by argon as the protective gas, with a CO ₂ laser spot with a diameter of 12mm as the heat source, and the scanning speed is 200mm/min. The dried brazing filler metal mixture melts and spreads the coating brazing filler metal, and realizes metallurgical bonding with the base of the shield hob cutter ring 3 to obtain the brazing filler metal coating 2;

D. On the surface of the brazing filler metal coating 2 obtained in step C, repeat steps B and C until the coating thickness reaches 5 mm, that is, a gradient wear-resistant coating 1 is obtained on the surface of the shield hob cutter ring 3 .

Example 4

The preparation method of the wear-resistant coating 1 provided by this embodiment specifically includes the following steps:

A. Calculated in parts by mass, weigh 6 parts of diamond micropowder (200-325 mesh), 3 parts of terpineol, 1 part of sodium fluoride and 90 parts of BNi-2 solder powder (200-300 mesh), mix thoroughly , stirring to prepare a paste solder mixture for use;

B. Coat the paste solder mixture evenly on the working surface of shield hob cutter ring 3, control the thickness to 0.5mm, after cooling and drying, put it in a drying box, dry it at 95 ℃ for 2 hours, and dry the coating internal moisture;

C. Fix the dried shield hob cutter ring 3 on the high temperature resistant bracket, supplemented by argon as the protective gas, with a CO ₂ laser spot with a diameter of 14mm as the heat source, and the scanning speed is 280mm/min. The dried brazing filler metal mixture melts and spreads the coating brazing filler metal, and realizes metallurgical bonding with the base of the shield hob cutter ring 3 to obtain the brazing filler metal coating 2;

D. On the surface of the brazing filler metal coating 2 obtained in step C, repeat steps B and C until the coating thickness reaches 6 mm, that is, a gradient wear-resistant coating 1 is obtained on the surface of the shield hob cutter ring 3 .

Example 5

The preparation method of the wear-resistant coating 1 provided by this embodiment specifically includes the following steps:

A. Calculated in parts by mass, weigh 7 parts of diamond micropowder (230-270 mesh), 4 parts of terpineol, 2 parts of sodium fluoride and 92 parts of BNi-2 solder powder (200-300 mesh), mix thoroughly , stirring to prepare a paste solder mixture for use;

B. Coat the paste solder mixture evenly on the working surface of shield hob cutter ring 3, control the thickness to be 0.7mm, after cooling and drying, put it in a drying box, and dry it at 85 ℃ for 2 hours, and dry the coating internal moisture;

C. Fix the dried shield hob cutter ring 3 on the high temperature resistant bracket, supplemented by argon as the protective gas, with a CO ₂ laser spot with a diameter of 15mm as the heat source, and the scanning speed is 300mm/min. The dried brazing filler metal mixture melts and spreads the coating brazing filler metal, and realizes metallurgical bonding with the base of the shield hob cutter ring 3 to obtain the brazing filler metal coating 2;

D. On the surface of the brazing filler metal coating 2 obtained in step C, repeat steps B and C until the coating thickness reaches 6 mm, that is, a gradient wear-resistant coating 1 is obtained on the surface of the shield hob cutter ring 3 .

Example 6

The preparation method of the wear-resistant coating 1 provided by this embodiment specifically includes the following steps:

A. Calculated in parts by mass, weigh 8 parts of diamond micropowder (200-325 mesh), 5 parts of terpineol, 3 parts of sodium fluoride and 84 parts of BNi-2 solder powder (200-300 mesh), mix thoroughly , stirring to prepare a paste solder mixture for use;

B. Coat the paste brazing material mixture evenly on the working surface of shield hob cutter ring 3, control the thickness to 0.7mm, after cooling and drying, put it in a drying box, dry it at 100 ℃ for 1.5h, and dry it for coating moisture inside the layer;

C. Fix the dried shield hob cutter ring 3 on the high temperature resistant bracket, supplemented by argon as the protective gas, with a CO ₂ laser spot with a diameter of 12mm as the heat source, and the scanning speed is 330mm/min. The dried brazing filler metal mixture melts and spreads the coating brazing filler metal, and realizes metallurgical bonding with the base of the shield hob cutter ring 3 to obtain the brazing filler metal coating 2;

D. On the surface of the brazing filler metal coating 2 obtained in step C, repeat steps B and C until the coating thickness reaches 6 mm, that is, a gradient wear-resistant coating 1 is obtained on the surface of the shield hob cutter ring 3 .

Example 7

The preparation method of the wear-resistant coating 1 provided by this embodiment specifically includes the following steps:

A. Calculated in parts by mass, weigh 9 parts of diamond micropowder (230-270 mesh), 2 parts of terpineol, 1 part of sodium fluoride and 88 parts of BNi-2 solder powder (230-270 mesh), mix thoroughly , stirring to prepare a paste solder mixture for use;

B. Coat the paste solder mixture evenly on the working surface of the shield hob cutter ring 3, control the thickness to 0.5mm, after cooling and drying, put it in a drying box, dry it at 85 ℃ for 2 hours, and dry the coating internal moisture;

C. Fix the dried shield hob cutter ring 3 on the high temperature resistant bracket, supplemented by argon as the protective gas, with a CO ₂ laser spot with a diameter of 15mm as the heat source, and the scanning speed is 350mm/min. The dried brazing filler metal mixture melts and spreads the coating brazing filler metal, and realizes metallurgical bonding with the base of the shield hob cutter ring 3 to obtain the brazing filler metal coating 2;

D. On the surface of the brazing filler metal coating 2 obtained in step C, repeat steps B and C until the coating thickness reaches 5 mm, that is, a gradient wear-resistant coating 1 is obtained on the surface of the shield hob cutter ring 3 .

Example 8

The preparation method of the wear-resistant coating 1 provided by this embodiment specifically includes the following steps:

A. Calculated in parts by mass, weigh 10 parts of diamond micropowder (200-325 mesh), 6 parts of terpineol, 5 parts of sodium fluoride and 81 parts of BNi-2 solder powder (200-300 mesh), mix thoroughly , stirring to prepare a paste solder mixture for use;

B. Coat the paste solder mixture evenly on the working surface of shield hob cutter ring 3, and control the thickness to be 0.5-0.7mm. After cooling and drying, put it into a drying box, and dry it at 99 °C for 2 hours. Moisture inside the coating;

C. Fix the dried shield hob cutter ring 3 on the high temperature resistant bracket, supplemented by argon as the protective gas, with a CO ₂ laser spot with a diameter of 15mm as the heat source, and the scanning speed is 350mm/min. The dried brazing filler metal mixture melts and spreads the coating brazing filler metal, and realizes metallurgical bonding with the base of the shield hob cutter ring 3 to obtain the brazing filler metal coating 2;

D. On the surface of the brazing filler metal coating 2 obtained in step C, repeat steps B and C until the coating thickness reaches 6 mm, that is, a gradient wear-resistant coating 1 is obtained on the surface of the shield hob cutter ring 3 .

Examples 9-16 are shield hob cutters with the wear-resistant coating 1 prepared in Examples 1-8.

Comparative Example 1

The coating material and coating thickness of this comparative example are the same as those in Example 1, but the preparation method is different. Preparation method: fully mix and stir the coating materials to prepare a paste-like mixture, coat the paste-like mixture on the working surface of the knife ring, control the thickness to be 6mm, and prepare the coating by a surfacing method.

Comparative Example 2

The coating material of this comparative example is the same as that of Example 1, but the preparation method is different. Preparation method: fully mix and stir the coating materials to prepare a paste-like mixture, coat the paste-like mixture on the working surface of the cutter ring, control the thickness to 0.5mm, prepare the first layer of coating by the surfacing method. The surface of the coating is then coated with a 0.5mm thick paste mixture, followed by surfacing to prepare a second layer of coating, the surface of the second coating is coated with a 0.5mm thick paste mixture, and a third layer is prepared by surfacing again. And so on, until the coating thickness reaches the requirements.

Comparative Example 3

The coating material of this comparative example is the same as that of Example 1, except that the preparation method is slightly different, and the multiple coating is changed to one coating to a total thickness of 6 mm, and brazing in the furnace is carried out.

Comparative Example 4

Uncoated.

Experimental example

In order to compare and illustrate the difference in wear resistance of the coating between the embodiment of the present invention and the comparative example, the same specification of cutter ring was selected for testing: a TBM disc-shaped hob cutter ring with an outer diameter of 100 mm and a thickness of 7 mm, and the material was H13 steel. On this TBM disc hob cutter ring of the same specification, the methods of Examples 1-8 and Comparative Examples 1-3 were used to prepare the hob cutter ring with thick coating, and the coating thickness was controlled at 5mm. The wear test was carried out with different coated cutter rings as the test objects. The test was carried out on a self-developed wear test bench. The test rock was a granite rock commonly used in TBM projects, and the rock size was 1000mm × 500mm × 300mm. The rock is fixed on the workbench of the test bench, the cutter ring is installed on the drive shaft through a key connection, and the drive shaft is driven by a hydraulic motor to achieve rotary motion. The speed of the drive shaft is 20r/min, and the test time is 3h. Try to ensure that the average contact stress between the cutter ring and the rock during the test is the same. The wear amount of the cutter ring after the wear test was tested, and the results are shown in Table 1.

Table 1 The wear amount of the cutter ring and the analysis results of the coating after the wear test

Wear test/3h Wear/g Analysis results Example 1 4.62 The thick coating is intact, and the diamond has no burning loss Example 2 4.55 The thick coating is intact, and the diamond has no burning loss Example 3 4.37 The thick coating is intact, and the diamond has no burning loss Example 4 4.23 The thick coating is intact, and the diamond has no burning loss Example 5 3.84 The thick coating is intact, and the diamond has no burning loss Example 6 3.68 The thick coating is intact, and the diamond has no burning loss Example 7 3.45 The thick coating is intact, and the diamond has no burning loss Example 8 3.26 The thick coating is intact, and the diamond has no burning loss Comparative Example 1 10.65 The base of the cutter ring is deformed, and the surface diamond is slightly thermally damaged Comparative Example 2 13.54 The knife ring is seriously deformed, and the diamond is almost completely burned out Comparative Example 3 9.32 The knife ring is slightly deformed, and the diamond part is burnt Comparative Example 4 14.45 uncoated

The experimental results show that, from the comparison in Table 1, it can be seen that the wear resistance of the cutter ring prepared by using the wear-resistant coating provided by the present application is better, and the service life of the cutter is significantly improved.

Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; those of ordinary skill in the art should understand that: Under the circumstance that deviates from the spirit and scope of the present invention, the technical solutions recorded in the foregoing embodiments may be modified, or some or all of the technical features thereof may be equivalently replaced; and these modifications or replacements do not make the corresponding technical solutions. Essentially depart from the scope of the technical solutions of the embodiments of the present invention; therefore, it is intended that all such substitutions and modifications that fall within the scope of the present invention be included in the appended claims.

Claims (12)

1. The cutter ring of the shield hobbing cutter is characterized in that a wear-resistant coating is coated on the surface of the cutter ring, and the thickness of the wear-resistant coating is 5-6 mm;

the wear-resistant coating comprises at least two layers of the same brazing filler metal coating;

the brazing filler metal coating is prepared from the following components in parts by mass:

3-10 parts of diamond micro powder, 2-6 parts of alcohol solvent, 1-5 parts of sodium fluoride and 81-93 parts of nickel-based brazing filler metal;

the coating thickness of the brazing filler metal coating is 0.5-0.7 mm;

the preparation method of the wear-resistant coating comprises the following steps:

(a) coating a brazing filler metal mixture of diamond micro powder, an alcohol solvent, sodium fluoride and a nickel-based brazing filler metal on the surface of a substrate, drying the brazing filler metal mixture to lose moisture, scanning the dried brazing filler metal mixture by adopting laser under the condition of protective gas, melting and spreading the brazing filler metal, and then realizing metallurgical bonding with the substrate to obtain a brazing filler metal coating;

the granularity of the diamond micro powder is 200-325 meshes;

the nickel-based brazing filler metal is a powdery material, and the granularity of the powdery material is 200-300 meshes;

(b) optionally repeating step (a) until a wear resistant coating of a desired thickness is obtained.

2. The cutter ring of the shield hob according to claim 1, wherein the particle size of the powdery material is 230 to 270 mesh.

3. The cutter ring of the shield hob according to claim 1, wherein the diamond micro powder has a particle size of 230 to 270 meshes.

4. The cutter ring of the shield hob according to claim 1, wherein the brazing filler metal coating is prepared from the following components in parts by mass:

5-8 parts of diamond micro powder, 3-5 parts of alcohol solvent, 1-3 parts of sodium fluoride and 80-90 parts of nickel-based brazing filler metal.

5. The cutter ring of the shield hobbing cutter of claim 1 or 4, wherein the nickel-based brazing filler metal is BNi-2.

6. The cutter ring of the shield hob according to claim 1 or 4, wherein the alcohol solvent is selected from C8-10 alcohol solvents.

7. The shield hob ring of claim 6, wherein the alcohol solvent is selected from terpineol.

8. The shield hob ring of claim 1, wherein in step (a), the laser is CO₂The laser spot is a heat source;

the diameter of the laser spot is 12-15 mm, and the scanning speed is 200-380 mm/min.

9. The shield hob ring of claim 1, wherein the protective gas is argon.

10. The shield hob ring of claim 5, wherein in the step (a), the drying is drying, the drying temperature is 85-100 ℃, and the drying time is 1.5-2 h.

11. A shield hob comprising the rim of the shield hob according to any one of claims 1 to 10.

12. A shield tunneling machine incorporating the shield hob of claim 11.

Images