阅读说明：本技术 镍基耐磨合金粉以及在钢基材表面熔覆耐磨涂层的方法 (Nickel-based wear-resistant alloy powder and method for cladding wear-resistant coating on surface of steel substrate ) 是由 胡登文 陈辉 刘艳 王梦超 刘晋 于 2021-01-05 设计创作，主要内容包括：本发明公开了一种镍基耐磨合金粉以及在钢基材表面熔覆耐磨涂层的方法,该合金粉按重量百分比包括Ta：40～50％、TiC：0.1～2％和Ni包覆石墨粉：20～25％,余量为Ni和不可避免的微量杂质。通过激光熔覆的方式将上述镍基耐磨合金粉在钢基材表面激光熔覆形成耐磨涂层,形成的耐磨涂层可以使得钢件兼具较佳的耐磨性能和高强韧性,从而有利于其应用于高性能模具和隧道盾构掘进刀圈,减少损耗,进而降低生产成本。(The invention discloses a nickel-based wear-resistant alloy powder and a method for cladding a wear-resistant coating on the surface of a steel substrate, wherein the alloy powder comprises the following components in percentage by weight: 40-50% and TiC: 0.1-2% and Ni-coated graphite powder: 20-25%, and the balance of Ni and inevitable trace impurities. The nickel-based wear-resistant alloy powder is subjected to laser cladding on the surface of a steel base material in a laser cladding mode to form a wear-resistant coating, and the formed wear-resistant coating can enable a steel piece to have good wear resistance and high toughness, so that the nickel-based wear-resistant alloy powder is favorably applied to high-performance dies and tunnel shield tunneling cutter rings, the loss is reduced, and the production cost is further reduced.)

1. The nickel-based wear-resistant alloy powder is characterized by comprising the following components in percentage by weight: 40-50% and TiC: 0.1-2% and Ni-coated graphite powder: 20-25%, and the balance of Ni and inevitable trace impurities.

2. The nickel-based wear-resistant alloy powder according to claim 1, wherein the mass ratio of Ni to C in the Ni-coated graphite powder in the composition is 70-80: 20-30, preferably 75: 25.

3. the nickel-based wear-resistant alloy powder according to claim 1 or 2, wherein the particle sizes of the components are 150 to 300 mesh.

4. A method for cladding a wear-resistant coating on the surface of a steel substrate is characterized by comprising the following steps: cladding the components in the nickel-based wear-resistant alloy powder disclosed by any one of claims 1-3 on the surface of a steel substrate in a laser cladding manner to form a wear-resistant coating.

5. The method for cladding the wear-resistant coating on the surface of the steel substrate according to claim 4, wherein the thickness of the wear-resistant coating is 1.5-3 mm.

6. The method for cladding the wear-resistant coating on the surface of the steel substrate according to the claim 4, wherein the laser cladding process parameters for forming the wear-resistant coating are as follows: the laser power is 1-2 kw, the cladding speed is 1-3 mm/s, the lap joint rate is 28-32%, the diameter of a laser spot is 5 multiplied by 5mm, a coaxial powder feeding mode is adopted, the powder feeding rate is 10-15 g/min, and the argon flow is 10-15L/min.

7. The method for cladding the wear-resistant coating on the surface of the steel substrate according to any one of claims 4 to 6, wherein the steel substrate is preheated at the preheating temperature of 300-400 ℃ for 25-30 min before laser cladding;

preferably, the surface of the steel base material is polished before preheating, so that the surface roughness of the steel base material reaches Ra3.2-6.3;

preferably, the steel substrate is 5Cr5MoSiV steel.

8. Method for cladding a wear resistant coating on a steel substrate surface according to any of the claims 4 to 6, characterized in that said wear resistant coating is formed by two laser cladding, preferably the first laser cladding forms 35 to 45% of the preset thickness of said wear resistant coating and the second laser cladding forms the remaining preset thickness of said wear resistant coating;

preferably, after the wear-resistant coating is formed, the heat preservation treatment is carried out in a resistance furnace at the temperature of 300-400 ℃ for 3-4 hours.

9. A steel article obtained after treatment of a steel substrate by laser cladding a wear resistant coating on the surface of the steel substrate according to claim 1.

10. Use of a steel part according to claim 9 for the manufacture of a mould or a tunnel shield driving cutter ring.

Technical Field

The invention relates to the technical field of metal, in particular to nickel-based wear-resistant alloy powder and a method for cladding a wear-resistant coating on the surface of a steel substrate.

Background

The 21 st century is the age of the great development of tunnels and underground spaces, and with the vigorous construction of super underground projects such as high-speed railways, drinking water projects, urban subways, national defense projects, coal mine excavation, highway tunnels and the like, higher requirements are put forward on special equipment and basic parts of tunnel projects. The shield machine/TBM is a special machine for tunneling tunnels, is widely applied to the tunneling of tunnels at home and abroad, the cutter is the tooth of the tunneling machine, and the service life of the cutter of the tunneling machine determines the construction safety and progress. In the process of shield/TBM tunneling, under the action of rock breaking thrust, the hob generates severe friction and abrasion with hard mineral phases in rock and soil, the hob needs to be stopped continuously to replace a hob ring, so that the construction cost, risk and construction period are increased, the consumption of the hob ring accounts for about 30% of the total construction cost of the shield/TBM, and the annual demand reaches more than 20 hundred million yuan. Therefore, the development of a high-toughness shield machine cutter ring with long service life is urgently needed to meet the tunneling requirement of complex rock and soil. The existing cutter ring is subjected to rolling forming, vacuum quenching and three-time tempering, the hardness reaches 56-60HRC, and the tensile strength reaches about 2200MPa, so that the wear resistance of the cutter ring is difficult to improve from the aspect of improving the performance of steel, and a surface treatment mode is required to be adopted for strengthening.

The in-situ synthesis generates a ceramic phase and intermetallic compound particles with high hardness and high wear resistance, which can obviously enhance the matrix performance, but the intermetallic compound generally has higher brittleness and is easy to crack, so the existing coating cannot have the performances of high toughness and high wear resistance.

In view of this, the invention is particularly proposed.

Disclosure of Invention

The invention aims to provide nickel-based wear-resistant alloy powder and a method for cladding a wear-resistant coating on the surface of a steel substrate so as to improve the technical problem.

The invention is realized by the following steps:

in a first aspect, the invention provides a nickel-based wear-resistant alloy powder, which comprises the following components in percentage by weight: 40-50% and TiC: 0.1-2% and Ni-coated graphite powder: 20-25%, and the balance of Ni and inevitable trace impurities.

In a second aspect, the present invention also provides a method of cladding a wear resistant coating on a surface of a steel substrate, comprising: the nickel-based wear-resistant alloy powder is cladded on the surface of a steel base material in a laser cladding mode to form a wear-resistant coating.

In a third aspect, the invention further provides a steel part which is obtained by processing the steel base material through the method for cladding the wear-resistant coating on the surface of the steel base material through laser.

In a fourth aspect, the invention also provides an application of the steel piece in preparation of a mold or a tunnel shield tunneling cutter ring.

The invention has the following beneficial effects: the coating with better wear resistance is formed by laser cladding in the nickel-based wear-resistant alloy powder, and because the TiC particles are added, the TaC takes TiC as a heterogeneous core to generate small TaC particles in situ, thereby inhibiting the Ni of a long lath₃Ta intermetallic compound is generated, and the hardness of the obtained cladding layer is equivalent to that without TiC, but the toughness is obviously improved. Therefore, the wear-resistant coating is formed on the surface of the steel base material, so that the steel piece has better wear resistance, and the wear-resistant coating is favorable for being applied to high-performance dies and tunnel shield tunneling cutter rings, reduces loss and further reduces production cost.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a comparative diagram of flaw detection of a laser cladding cutter ring and a cladding layer, wherein (a) in fig. 1 is a schematic diagram of the cladding cutter ring; (b) and (c) are respectively a graph of the appearance and the dye check effect after laser cladding in comparative example 1, and (d) and (e) are respectively a graph of the appearance and the dye check effect after laser cladding in example 1;

FIG. 2 is a SEM microstructure map of a laser cladding in-situ synthesized wear-resistant coating, wherein (a), (b) and (c) in FIG. 2 are SEM microstructure maps of a wear-resistant coating of comparative example 1; (d) the (e) and the (f) are SEM microstructure and morphology images of the wear-resistant coating of the example 1;

fig. 3 is an EBSD phase distribution diagram of a laser cladding in-situ synthesized wear-resistant coating, wherein (a) in fig. 3 is the EBSD phase distribution diagram of the wear-resistant coating of comparative example 1, and (b) is the EBSD phase distribution diagram of the wear-resistant coating of example 1;

fig. 4 is a graph comparing hardness and wear resistance of the wear-resistant coating after laser cladding, wherein (a) in fig. 4 is a graph comparing hardness distribution of the coatings of the steel members of comparative example 1 and example 1, and (b) is a graph comparing wear performance of the steel members of example 1, comparative example 1, and comparative example 2.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The nickel-based wear-resistant alloy powder and the method for cladding the wear-resistant coating on the surface of the steel substrate provided by the invention are specifically described below.

The inventor finds that the wear-resistant coating is prepared on the surface of the cutter ring in a mode of synchronously feeding powder by laser cladding, and compared with surfacing, spray welding, spraying, electroplating and vapor deposition, the laser cladding has the advantages of small dilution, compact structure, good combination of the coating and a matrix, more suitable cladding materials, and large particle size and content change. However, in the existing process of forming a wear-resistant coating of a high-hardness and high-wear-resistance ceramic phase and intermetallic compound particles through laser cladding, the intermetallic compound is generally high in brittleness and easily causes cracking, and further the performance of the wear-resistant coating is poor. Therefore, the inventors further proposed the following technical solutions through a great deal of research and practice on the basis of this.

Some embodiments of the present invention provide a nickel-based wear-resistant alloy powder, which comprises, by weight, Ta: 40-50% and TiC: 0.1-2% and Ni-coated graphite powder: 20-25%, and the balance of Ni and inevitable trace impurities.

A coating with strong wear resistance is formed by laser cladding, and TiC particles are added into the components, so that TaC takes TiC as a heterogeneous core, and TaC small particles are generated in situ, thereby inhibiting long lath-shaped Ni₃Ta intermetallic compounds are generated, the hardness of the obtained cladding layer is equivalent to that without TiC, but the toughness is obviously improved, and the formed coating has high strength and toughness and high wear resistance.

In some embodiments, in order to achieve a better effect, the composition ratio of the components of the nickel-based wear-resistant alloy powder is further optimized, and the nickel-based wear-resistant alloy powder comprises, by weight, Ta: 45-49% and TiC: 1-1.5% and Ni-coated graphite powder: 20-23%, and the balance of Ni and inevitable trace impurities.

Further, in some embodiments, the mass ratio of Ni and C of the Ni-coated graphite powder is 70-80: 20-30, preferably 75: 25.

further, the selection of the particle size of the components can affect the mixing uniformity among the components and the laser cladding effect, so that in some embodiments, the particle size of the components is 150-300 meshes. Through the selection of the particle size, the components can be fully and uniformly mixed, and the melting of the Ni-based wear-resistant alloy powder is facilitated during laser cladding.

Some embodiments of the present invention also provide a method of cladding a wear resistant coating on a surface of a steel substrate, comprising: the nickel-based wear-resistant alloy powder is subjected to laser cladding on the surface of a steel base material in a laser cladding mode to form a wear-resistant coating.

The wear-resistant coating can be generated on the surface of the steel base material through in-situ reaction in a laser cladding mode, and the coating has good bonding performance and uniformity.

In order to meet the requirements related to surface treatment and wear resistance of steel parts, the thickness of the wear-resistant coating is 1.5-3 mm in some embodiments.

Further, the selection of laser cladding parameters has a great influence on the effect, wherein the larger the laser power is, the more the amount of the molten cladding metal is, and the higher the probability of generating the air holes is. Along with the increase of the laser power, the depth of the cladding layer is increased, the surrounding liquid metal is fluctuated violently, and the liquid metal is solidified and crystallized dynamically, so that the number of air holes is gradually reduced and even eliminated, and the cracks are also gradually reduced. When the depth of the cladding layer reaches the limit depth, the surface temperature of the substrate rises along with the increase of the power, the phenomena of deformation and cracking are aggravated, the laser power is too low, only the surface coating is melted, the substrate is not melted, and at the moment, local balling, cavities and the like appear on the surface of the cladding layer, so that the purpose of surface cladding cannot be achieved. The width of the cladding layer is mainly determined by the spot diameter of the laser beam, and the spot diameter increases and the cladding layer becomes wider. The different sizes of the light spots can cause the surface energy distribution of the cladding layer to change, and the obtained cladding layer has larger difference in appearance and structure performance. Generally, the quality of the cladding layer is better at a small-sized spot, and the quality of the cladding layer is reduced as the spot size increases. However, the diameter of the light spot is too small, which is not favorable for obtaining a large-area cladding layer. The cladding speed V has a similar effect as the laser power P. The cladding speed is too high, the alloy powder can not be completely melted, and the effect of high-quality cladding is not achieved; the cladding speed is too low, the existing time of a molten pool is too long, powder is over-sintered, alloy elements are lost, and meanwhile, the heat input quantity of a matrix is large, so that the deformation quantity can be increased. The overlapping rate is a main factor influencing the surface roughness of the cladding layer, the overlapping rate is improved, the surface roughness of the cladding layer is reduced, but the uniformity of the overlapping part is difficult to ensure. The depth of the mutual overlapping area between the cladding channels is different from the depth of the middle of the cladding channel, thereby influencing the uniformity of the whole cladding layer. And the residual tensile stress of the multi-channel lap cladding can be overlapped, so that the local total stress value is increased, and the crack sensitivity of the cladding layer is increased. Preheating and tempering reduce the tendency of the cladding to crack.

Therefore, in the embodiment of the invention, the above factors are comprehensively considered, and the laser cladding process parameters for forming the wear-resistant coating are selected as follows: the laser power is 1-2 kw, the cladding speed is 1-3 mm/s, the lap joint rate is 28-32%, the diameter of a laser spot is 5 multiplied by 5mm, a coaxial powder feeding mode is adopted, the powder feeding rate is 10-15 g/min, and the argon flow is 10-15L/min. The method can be suitable for cladding the wear-resistant alloy powder on the surface of a steel substrate, particularly a 5Cr5MoSiV steel substrate, and achieves a good cladding effect. It should be noted that the laser cladding parameters do not affect the macroscopic and microscopic quality of the cladding layer independently, but affect each other.

In some embodiments, in order to enable the steel substrate to be better combined with the alloy powder, the steel substrate needs to be preheated before laser cladding, the preheating temperature can be 300-400 ℃, and the preheating time can be 25-30 min.

Meanwhile, the surface of the steel base material can be better in combination performance between the coating and the base material only by having certain roughness, so that in some embodiments, the surface of the steel base material is polished before preheating, so that the surface roughness reaches Ra3.2-6.3. After polishing, impurities may be removed by cleaning with alcohol or the like.

The steel substrate may be 5Cr5MoSiV steel.

Further, after the wear-resistant coating is formed, heat preservation treatment is carried out for 3-4 hours at the temperature of 300-400 ℃. And residual stress left by laser cladding is further reduced by means of heat preservation treatment.

According to the embodiment of the invention, by adopting the preheating treatment and the post-heating treatment, the difference of the thermal expansion coefficients of the base material and the cladding material can be reduced, so that the cladding material and the base material are effectively metallurgically bonded, the cladding effect is good, and the cracking is obviously inhibited.

Further, the wear-resistant coating is formed by two times of laser cladding, preferably, 35-45% of the preset thickness of the wear-resistant coating is formed by the first time of laser cladding, and the residual preset thickness of the wear-resistant coating is formed by the second time of laser cladding. For example, the first laser cladding forms 40% of the preset thickness of the wear-resistant coating. When the wear-resistant coating is formed by the first laser cladding, the quality of the wear-resistant coating can be influenced by the mutual combination of the surface of the base material and the wear-resistant alloy powder.

Some embodiments of the present invention also provide a method of cladding a wear resistant coating on a surface of a steel substrate, specifically comprising:

s1, polishing and flattening the surface of the 5Cr5MoSiV steel substrate, wherein the surface roughness is Ra3.2-6.3, removing impurities by using alcohol, and preheating the steel substrate on a resistance preheating plate for 25-30 min at the preheating temperature of 300-400 ℃.

S2, forming a wear-resistant coating on the surface of the 5Cr5MoSiV steel substrate by the Ni-based wear-resistant alloy powder through a laser cladding method, wherein the thickness of the first wear-resistant coating is 0.5-1.2 mm, and the thickness of the second wear-resistant coating is 0.8-1.5 mm. The cladding process for forming the first wear-resistant coating and the second wear-resistant coating is as follows: the laser power is 1-2 kw, the cladding speed is 1-3 mm/s, the lap joint rate is 30%, and the diameter of a laser spot is as follows: 5 multiplied by 5mm, a coaxial powder feeding mode is adopted, the powder feeding rate is 10-15 g/min, and the argon flow is as follows: 10 to 15L/min.

S5, carrying out heat preservation treatment on the steel piece obtained after cladding in a furnace at 300-400 ℃ for 3-4 h.

Some embodiments of the invention also provide a steel part obtained after treatment of a steel substrate by the above-described method of cladding a wear-resistant coating on the surface of the steel substrate.

Some embodiments of the invention also provide application of the steel piece in preparation of a mould or a tunnel shield tunneling cutter ring.

The features and properties of the present invention are described in further detail below with reference to examples.

Example 1

The Ni-based wear-resistant alloy powder provided by the embodiment is mainly used for preparing a wear-resistant coating on the surface of 5Cr5MoSiV steel after heat treatment, and is prepared by the following steps:

prepared by mixing commercially pure Ni powder (99.9%), pure Ta powder (99.9%), TiC powder (99%), Ni-coated graphite powder (Ni: C75: 25 mass ratio, 95%). Comprising Ta: 48%, Ni-coated graphite powder: 22%, TiC: 1.3%, the balance being Ni and inevitable trace impurities.

A5 Cr5MoSiV sample steel block (80 mm. times.50 mm. times.30 mm) cut from a 19-inch shield machine hob was used as a laser cladding substrate.

The process for preparing the wear-resistant coating on the surface of the wear-resistant 5Cr5MoSiV steel part comprises the following steps:

1) the surface of the 5Cr5MoSiV steel part is polished to be flat, the surface roughness is about Ra3.2, and impurities are removed by alcohol.

2) And (3) placing the 5Cr5MoSiV steel piece on a resistance preheating plate, fixing the steel piece and the resistance preheating plate on a workbench, and preheating on the resistance preheating plate at the preheating temperature of 300 ℃ for 30 min.

3) The Ni-based wear-resistant alloy powder is laser-cladded on the surface of a 5Cr5MoSiV steel piece, two wear-resistant layers are cladded, the thickness of the first layer is 0.8mm, the total thickness is 2mm, and the cladding process comprises the following steps: the laser power is 1.5kw, the cladding speed is 2mm/s, the lap-joint rate is 30%, and the diameter of a laser spot is as follows: 5 multiplied by 5mm, a coaxial powder feeding mode is adopted, the powder feeding rate is 15g/min, and the argon flow: 12L/min.

4) And (4) carrying out heat preservation treatment on the steel piece subjected to cladding in a furnace at 300 ℃ for 4 h.

Comparative example 1

The Ni-based wear-resistant alloy powder provided by the comparative example is mainly used for 5Cr5MoSiV steel and is prepared by the following steps:

prepared by mixing commercially pure Ni powder (99.9%), pure Ta powder (99.9%), TiC powder (99%), Ni-coated graphite powder (Ni: C75: 25 mass ratio, 95%). Comprising Ta: 48%, Ni-coated graphite powder: 23% and the balance of Ni and inevitable trace impurities.

A5 Cr5MoSiV sample steel block (80 mm. times.50 mm. times.30 mm) cut from a 19-inch shield machine hob was used as a laser cladding substrate.

The process for preparing the wear-resistant coating on the surface of the wear-resistant 5Cr5MoSiV steel part comprises the following steps:

1) the surface of the 5Cr5MoSiV steel part is polished to be flat, the surface roughness is about Ra3.2, and impurities are removed by alcohol.

2) And (3) placing the 5Cr5MoSiV steel piece on a resistance preheating plate, fixing the steel piece and the resistance preheating plate on a workbench, and preheating on the resistance preheating plate at the preheating temperature of 300 ℃ for 30 min.

3) The Ni-based wear-resistant alloy powder is laser-cladded on the surface of a 5Cr5MoSiV steel piece, two wear-resistant layers are cladded, the thickness of the first layer is 0.8mm, the total thickness is 2mm, and the cladding process comprises the following steps: the laser power is 1.5kw, the cladding speed is 2mm/s, the lap-joint rate is 30%, and the diameter of a laser spot is as follows: 5 multiplied by 5mm, a coaxial powder feeding mode is adopted, the powder feeding rate is 15g/min, and the argon flow: 12L/min.

4) And (4) carrying out heat preservation treatment on the steel piece subjected to cladding in a furnace at 300 ℃ for 4 h.

Comparative example 2

5Cr5MoSiV sample steel blocks (80mm multiplied by 50mm multiplied by 30mm) cut by the steel piece from a 19-inch shield machine hobbing cutter ring polish the surface of the 5Cr5MoSiV steel piece to be smooth, the surface roughness is about Ra3.2, the hardness is 56-58HRC, and the impact energy AKU: 20-30J.

Test examples

The appearance of the clad parts of the example 1 and the comparative example 1 is observed and the dye check test is carried out, and the steps are as follows: 1. cleaning the surfaces of the cladding parts in the example 1 and the comparative example 1 by using a cleaning agent; 2. placing the cleaned cladding pieces of the example 1 and the comparative example 1, and uniformly spraying a penetrant on the surface of the detected material; 3. after about 5-15 minutes of infiltration, using a cleaning agent to clean the penetrating agent sprayed on the surface of the workpiece; 4. and (3) fully shaking the developer uniformly, uniformly spraying the developer on the surface of the detected material at a distance of 150-300 mm, and after waiting for a few minutes, displaying the defects.

Fig. 1 (a) is a schematic view of a cladding cutter ring, and fig. 1 (b) and (c) are graphs of the appearance and the dye check effect after laser cladding in comparative example 1. It can be seen that the cladding layer completely covers the substrate to form a wear-resistant protective layer, and long straight cracks appear in dye penetrant inspection, indicating that high brittleness phase synthesis exists. In fig. 1, (d) and (e) are graphs of the morphology and the dye check effect after laser cladding in example 1, and it is found that cracks are significantly reduced, indicating that brittle phases are suppressed.

The microstructure of the just-seen coating structures of example 1 and comparative example 1 was observed by SEM, and the structures are shown in fig. 2, and (a) to (c) in fig. 2 are SEM images of the coating after laser cladding in comparative example 1, and it can be seen that a long lath phase was present and a small particle phase was less in the coating. Fig. 2 (d) - (f) are SEM images of the coating after laser cladding in example 1, and it can be seen that the coating contains a large amount of small particles and is significantly aggregated near the TiC particles.

FIG. 3 (a) is the EBSD phase composition of the coating after laser cladding in comparative example 1Layout, it can be seen that the red Ni is the binder phase in the coating and the blue long lath phase is the in situ synthesized Ni₃Ta intermetallic compound is a typical brittle phase, and yellow small particle phase is TaC small particles synthesized in situ; fig. 3 (b) is an EBSD phase distribution diagram of the coating after laser cladding in example 1, and it can be seen that red Ni is a binder phase in the coating, a yellow large particle phase is an added TiC phase, and a blue small particle phase is an in-situ synthesized TaC small particle, and the particles are obviously aggregated near the TiC phase, indicating that the added TiC can be an effective heterogeneous core, promoting the formation of TaC particles, and Ni is an EBSD phase distribution diagram of the coating after laser cladding₃Ta phase is not obvious, indicating that the addition of TiC inhibits Ni₃And forming Ta.

Fig. 4 (a) is a comparison of the hardness profiles of comparative example 1 and example 1, and it was found that the addition of TiC had no significant effect on the hardness of the coatings, and the hardness of the two coatings was comparable. Fig. 4 (b) is a graph comparing the wear properties of example 1, comparative example 1 and comparative example 2, and it was found that after laser-producing the coatings, the wear resistance of both coatings was about 4 times that of the coatings without the coatings. The addition of TiC does not affect the wear resistance of the coating, but obviously improves the toughness, and is beneficial to preparing the wear-resistant coating on the surface of the shield tunneling machine/TBM hob ring.

In summary, the embodiments of the present invention have the following advantages:

1. the surface wear-resistant layer is made of the 5Cr5MoSiV steel piece with the hardness reaching 56-58HRC after heat treatment, so that the service life of the steel piece can be prolonged.

2. The Ni-based alloy powder provided by the embodiment of the invention has the advantages of simple preparation method and obviously improved wear resistance.

3. By adopting the preheating treatment and the post-heating treatment, the difference of the thermal expansion coefficients of the base material and the cladding material can be reduced, so that the cladding material and the base material are effectively metallurgically bonded, and the cladding effect is good.

4. The coating processing method provided by the embodiment of the invention can be widely applied to surface strengthening treatment of the shield hob ring.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.