A carbon steel surface cladding gradient copper coating and a preparation method thereof

Abstract

The present application belongs to the technical field of metal coating, and particularly relates to a carbon steel surface cladding gradient copper coating and a preparation method thereof. In order to improve the wear resistance of carbon steel, improve the bonding force between the coating and the carbon steel, and prolong the service life, the present application utilizes the super-speed laser cladding technology and the ultrasonic rolling technology to prepare a copper-based alloy composite wear-resistant coating with internal organization gradient on the surface of the carbon steel substrate. First, the copper-based alloy cladding powder is cladded as an inner layer on the surface of the carbon steel substrate, then the SiC ceramic reinforced copper-based wear-resistant powder is cladded as an outer layer on the inner layer, and the outer layer is subjected to ultrasonic rolling treatment, and finally the carbon steel surface cladding gradient copper coating is obtained after cleaning.

Description

Technical Field

[0001] The invention belongs to the technical field of metal coatings, and in particular relates to a carbon steel surface cladding gradient copper coating and a preparation method thereof. Background Art

[0002] Carbon steel has been widely used in manufacturing, construction, and mechanical engineering due to its good mechanical properties, low cost, and wide resource availability. However, carbon steel also has inherent defects, such as poor corrosion resistance and limited wear resistance. Especially in humid and corrosive environments, it is prone to wear and rust, which seriously affects the service life of mechanical equipment and components, causing economic losses.

[0003] Electroplating and spraying are commonly used surface coating preparation technologies, which mainly rely on physical bonding. The bonding force between the coating and the carbon steel substrate is weak, which makes it easy to wear and tear, and it is easy to peel off and delaminate under stress or thermal stress. The coating life is short and it can no longer meet the needs in many complex working conditions. At the same time, the chemical electrolyte in the electroplating process has certain pollution to the environment, and the dust and waste in the spraying are easy to pollute the air. Under the current environmental policies in the fields of energy conservation, emission reduction and green building, they are gradually being replaced.

[0004] Ultra-high-speed laser cladding technology is a technology that uses high-temperature energy to melt the coating material and deposit it on the surface of the substrate. Its advantage is that it can maintain a low dilution rate and obtain a fine and dense microstructure while ensuring a good metallurgical bond between the coating and the substrate. It can effectively improve the specific performance of the part surface and extend the service life of the part. It has been widely used in mechanical manufacturing, aerospace, petrochemical and other fields.

[0005] Existing laser cladding coating materials are primarily iron- and cobalt-based. However, iron-based coatings are prone to numerous defects during the preparation process, which can reduce the coating's performance and reliability. Cobalt-based coatings have poor mechanical properties and are relatively expensive, making them unsuitable for large-scale industrial production. In contrast, copper-based coatings offer not only excellent thermal and electrical conductivity, as well as corrosion resistance, but also good wear resistance, providing a more economical and practical solution for ultra-high-speed laser cladding technology.

[0006] However, a single copper-based coating still cannot meet the higher performance requirements in some harsh environments. Ceramic particles generally have very high hardness and can significantly improve the overall hardness and wear resistance of the coating when added to the copper-based coating, but at the same time, the performance difference between the coating and the carbon steel material is inevitably large, which is prone to interface defects or stress concentration. Therefore, by adjusting the overall structure to form a transition region, gradually transitioning from the carbon steel material to the ceramic reinforced copper-based coating, and at the same time, surface re-strengthening the ceramic reinforced copper-based coating, is a new idea to improve defects, enhance the overall stability and surface performance of the coating. SUMMARY

[0007] To solve the above problems, the purpose of the present application is to provide a carbon steel surface cladding gradient copper coating and its preparation method, which uses copper-based coating material to cladding the surface of carbon steel substrate, the inner layer is copper-based alloy cladding powder, the outer layer is SiC ceramic reinforced copper-based wear-resistant powder, and the surface of the cladding coating is treated by ultrasonic rolling to form a gradient structure. This gradient coating not only has excellent thermal conductivity and corrosion resistance, as well as good lubrication and low friction coefficient, effectively improving the wear resistance of the surface of the equipment and parts, but also can avoid the occurrence of key problems such as material cracking and severe deformation.

[0008] To achieve the above purpose, the present application adopts the following technical scheme:

[0009] On the one hand, the present application provides a preparation method of a carbon steel surface cladding gradient copper coating, comprising the following steps:

[0010] Step 1, select copper-based alloy cladding powder, SiC ceramic particles and carbon steel substrate, and pretreat the copper-based alloy cladding powder, SiC ceramic particles and carbon steel substrate respectively;

[0011] Step 2, mix the pretreated copper-based alloy cladding powder and the pretreated SiC ceramic particles in proportion by high-energy ball milling to obtain uniform SiC ceramic reinforced copper-based wear-resistant powder;

[0012] Step 3, use coaxial powder feeding method for the inner layer, set the inner layer cladding parameters, and use ultra-high-speed laser cladding technology to cladding the copper-based alloy cladding powder on the surface of the carbon steel substrate, and then cool it quickly;

[0013] Step 4, use coaxial powder feeding method for the outer layer, set the outer layer cladding parameters, and use ultra-high-speed laser cladding technology to cladding the SiC ceramic reinforced copper-based wear-resistant powder obtained in step 2 on the outer surface of the inner layer, and then naturally cool it to obtain a cladding SiC ceramic reinforced copper-based wear-resistant coating;

[0014] Step 5, ultrasonic rolling is performed on the outer surface of the cladding SiC ceramic reinforced copper-based wear-resistant coating;

[0015] Step 6: Cleaning the cladding gradient copper-based coating after ultrasonic rolling to obtain the cladding gradient copper coating on the carbon steel surface.

[0016] Furthermore, the copper-based alloy cladding powder in step 1 comprises, by weight percentage, 58-60% copper, 19.5-21% nickel, 6% molybdenum, 4.8-5% iron, 4.8-5% cobalt, 1.8-2.1% chromium, and 3% silicon;

[0017] In the step 1, the carbon steel substrate is made of 27SiMn alloy steel.

[0018] Furthermore, in step 1, the copper-based alloy cladding powder, SiC ceramic particles, and carbon steel substrate are pretreated respectively, wherein the pretreatment of the copper-based alloy cladding powder is specifically as follows: the copper-based alloy cladding powder is sieved using a sieve to keep the particle size of the copper-based alloy cladding powder between 25 and 50 μm, ultrasonically cleaned in anhydrous ethanol for 3 to 5 minutes at an ultrasonic frequency of 100 kHz, and then dried at 120 to 150° C. for 10 minutes; surface impurities and oil stains are removed to prevent pores and cracks from being generated during the cladding process, thereby ensuring a clean interface between the copper-based alloy cladding powder and the carbon steel substrate, improving the wettability of the copper-based alloy cladding powder and the carbon steel substrate, and enhancing the bonding strength;

[0019] The SiC ceramic particles are pretreated by using a sieve to screen the SiC ceramic particles so that the average particle size of the SiC ceramic particles is maintained at 8 μm, washing the SiC ceramic particles with deionized water and drying the SiC ceramic particles until the surface is dry.

[0020] The pretreatment of the carbon steel substrate is specifically as follows: wiping the surface of the carbon steel substrate with anhydrous ethanol and waiting for it to dry naturally.

[0021] Furthermore, in step 2, the mass ratio of the copper-based alloy cladding powder to the SiC ceramic particles is 9-19:1.

[0022] Furthermore, in step 2, the pretreated copper-based alloy cladding powder and the pretreated SiC ceramic particles are fully mixed in proportion by high-energy ball milling, specifically:

[0023] The pretreated SiC ceramic particles and pretreated copper-based alloy cladding powder were loaded into a ball mill jar in proportion and placed in a high-energy ball mill. Zirconia balls were selected as the ball milling medium, the ball-to-material ratio was 8:1, the mixing time was set to 8 h, and the mixing speed was 1400 r / min to obtain uniform SiC ceramic reinforced copper-based wear-resistant powder.

[0024] Further, the inner layer cladding parameters set in step 3 include: laser power is 1500-2000W, scanning speed is 800-1500mm / min, single pass transverse amount is 1.0-1.5mm, overlapping rate is 40%, powder feeding amount is 15-25g / min, protective gas flow is 15-30L / min, and powder feeding gas flow is 6-10L / min.

[0025] Further, the outer layer cladding parameters set in step 4 include: laser power is 1300-1800W, scanning speed is 800-1500mm / min, single pass transverse amount is 1.0-1.5mm, overlapping rate is 40%, powder feeding amount is 15-25g / min, protective gas flow is 15-30L / min, and powder feeding gas flow is 6-10L / min.

[0026] Further, the specific conditions of ultrasonic rolling in step 5 are as follows: ultrasonic frequency is 25-30kHz, rolling pressure is 300-400N, rolling speed is 300-420mm / min, ultrasonic amplitude is 8-12μm, contact times is 3-6 times, and processing temperature is room temperature.

[0027] Further, the specific conditions of cleaning in step 6 are as follows: the surface of the cladding gradient copper-based coating after ultrasonic rolling is wiped with anhydrous ethanol, and naturally air-dried.

[0028] On the other hand, the application also provides a carbon steel surface cladding gradient copper coating prepared by the preparation method of the carbon steel surface cladding gradient copper coating.

[0029] Compared with the prior art, the application has the following advantages:

[0030] 1. The application adopts copper-based alloy cladding powder as the inner layer for transition, which has the following advantages: the transition layer can reduce the large difference in thermal expansion coefficient and physical properties between the outer layer cladding SiC ceramic reinforced copper-based wear-resistant coating and the carbon steel substrate, effectively relieve the stress concentration between the cladding SiC ceramic reinforced copper-based wear-resistant coating and the carbon steel substrate, and prevent the cladding SiC ceramic reinforced copper-based wear-resistant coating from cracking or delaminating due to thermal stress during cladding or subsequent use, thereby improving the overall bonding strength of the wear-resistant coating and the substrate surface.

[0031] 2、The application adopts ultrasonic rolling technology to perform surface treatment on the prepared cladding SiC ceramic reinforced copper-based wear-resistant coating, forms a grain gradually refined organization gradient from inside to outside surface in the wear-resistant coating, effectively increases the surface hardness and wear resistance, improves the surface density and uniformity to enhance the corrosion resistance, improves the fatigue resistance of the wear-resistant coating by introducing surface compressive stress, prolongs the service life, and at the same time can reduce the surface roughness, makes the surface more smooth, and further promotes the wear resistance.

[0032] 3、The application realizes the effective combination of ultrahigh-speed laser cladding technology and ultrasonic rolling technology, the copper-based alloy cladding powder is cladded on the outer surface of the carbon steel substrate by the ultrahigh-speed laser cladding technology, a good metallurgical bond is formed between the inner layer copper-based coating and the carbon steel substrate, and the ultrasonic rolling technology is performed on the surface of the cladding SiC ceramic reinforced copper-based wear-resistant coating, so that the wear resistance of the surface of the cladding SiC ceramic reinforced copper-based wear-resistant coating can be improved, the roughness can be reduced, the ultrasonic vibration in the ultrasonic rolling process can also reduce the residual stress on the surface and in the material caused by the ultrahigh-speed laser cladding technology, especially can effectively relieve the thermal stress difference between the carbon steel substrate and copper, enhance the bonding strength between the inner layer copper-based coating and the carbon steel substrate, and then improve the adhesion of the whole coating, while improving the hardness, reduce the risk of coating rupture caused by stress concentration. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The structure schematic diagram of the carbon steel surface cladding gradient copper coating prepared in examples 1 and 2.

[0034] Figure 2 The electron micrograph of the microstructure of the interface between the inner layer and the carbon steel substrate after ultrasonic rolling in example 2.

[0035] Figure 3 The electron micrograph of the microstructure of the interface between the outer layer and the inner layer after ultrasonic rolling in example 2.

[0036] Figure 4 The electron micrograph of the microstructure of the outer layer after ultrasonic rolling in example 2.

[0037] Figure 5 The surface hardness comparison diagram of the copper-based wear-resistant coating prepared in comparative examples 1-2 and examples 1-2.

[0038] Among them, 1 is the carbon steel substrate, 2 is the inner layer, and 3 is the outer layer. DETAILED DESCRIPTION

[0039] In order to further illustrate the technical scheme of the application, the application will be further described below through examples.

[0040] Comparative example 1

[0041] The comparative example adopts a preparation method of an ultra-high-speed laser cladding copper-based alloy coating, comprising the following steps:

[0042] Step 1, selecting a copper-based alloy cladding powder, a carbon steel substrate, the copper-based alloy cladding powder comprises, by weight percentage, copper 59%, nickel 20%, molybdenum 6%, iron 5%, cobalt 5%, chromium 2%, and silicon 3%, and the carbon steel substrate is selected to be 27SiMn alloy steel;

[0043] The copper-based alloy cladding powder is pretreated, specifically: the copper-based alloy cladding powder is sieved using a sieve screen to keep the particle size of the powder between 25-50 μm, is placed in anhydrous ethanol for ultrasonic cleaning for 3 min at an ultrasonic frequency of 100 kHz, and is then placed in a 120°C drying box for drying treatment for 10 min;

[0044] The carbon steel substrate is pretreated, specifically: the surface of the 27SiMn alloy steel substrate is wiped with anhydrous ethanol, and is allowed to air dry naturally.

[0045] Step 2, laser cladding of the copper-based alloy coating is performed using a coaxial powder feeding method (using a laser cladding device), and the laser cladding parameters are set as follows: laser power is 2500 W, scanning speed is 800 mm / min, single pass transverse amount is 1.2 mm, overlap rate is 40%, powder feeding amount is 30 g / min, protective gas flow rate is 25 L / min, and powder feeding gas flow rate is 9 L / min; the copper-based alloy cladding powder is cladded on the surface of the 27SiMn alloy steel substrate, and is allowed to cool naturally.

[0046] Step 3, the obtained copper-based alloy coating is wiped with anhydrous ethanol, and is allowed to air dry naturally, thereby obtaining a copper-based alloy coating on the surface of the carbon steel substrate.

[0047] Comparative Example 2

[0048] The comparative example adopts a preparation method of an ultra-high-speed laser cladding copper-based alloy coating, comprising the following steps:

[0049] Step 1, selecting a copper-based alloy cladding powder, SiC ceramic particles, and a carbon steel substrate, the copper-based alloy cladding powder comprises, by weight percentage, copper 59%, nickel 20%, molybdenum 6%, iron 5%, cobalt 5%, chromium 2%, and silicon 3%, and the carbon steel substrate is selected to be 27SiMn alloy steel;

[0050] The copper-based alloy cladding powder is pretreated, specifically: the copper-based alloy cladding powder is sieved using a sieve screen to keep the particle size of the powder between 25-50 μm, is placed in anhydrous ethanol for ultrasonic cleaning for 3 min at an ultrasonic frequency of 100 kHz, and is then placed in a 120°C drying box for drying treatment for 10 min;

[0051] The SiC ceramic particles are pretreated, specifically: the SiC ceramic particles are sieved using a sieve, so that the average particle size of the SiC ceramic particles is kept at 8 μm, washed with deionized water, and then dried in a 120°C drying box for 10 min;

[0052] The carbon steel substrate is pretreated, specifically: the surface of the 27SiMn alloy steel substrate is wiped with anhydrous ethanol, and it is allowed to air dry naturally.

[0053] Step 2: The pretreated copper-based alloy cladding powder and the pretreated SiC ceramic particles are mixed in proportion by high-energy ball milling to obtain a uniform SiC ceramic reinforced copper-based wear-resistant powder;

[0054] Specifically: the pretreated SiC ceramic particles and the pretreated copper-based alloy cladding powder are weighed in a mass ratio of 1:9 and placed in a ball mill jar, and then placed in a high-energy ball mill, zirconia balls are used as the ball milling medium, the ball-to-material ratio is 8:1, the mixing time is set to 8 h, the mixing speed is 1400 r / min, and after sufficient mixing, a uniform SiC ceramic reinforced copper-based wear-resistant powder is obtained.

[0055] Step 3: The inner layer is coated by the coaxial powder feeding method, the inner layer cladding parameters are set, and the copper-based alloy cladding powder is cladded on the surface of the carbon steel substrate by using the ultra-high-speed laser cladding technology, and then rapidly cooled;

[0056] The inner layer cladding parameters are set, including: the laser power is 2000 W, the scanning speed is 1200 mm / min, the single-pass transverse amount is 1.2 mm, the overlap rate is 40%, the powder feeding amount is 25 g / min, the protective gas flow is 20 L / min, the powder feeding gas flow is 8 L / min, and the protective gas is argon.

[0057] Step 4: The outer layer is coated by the coaxial powder feeding method, the outer layer cladding parameters are set, and the SiC ceramic reinforced copper-based wear-resistant powder obtained in step 2 is cladded on the outer surface of the inner layer by using the ultra-high-speed laser cladding technology, and then naturally cooled to obtain a cladded SiC ceramic reinforced copper-based wear-resistant coating;

[0058] The outer layer cladding parameters are set, including: the laser power is 1800 W, the scanning speed is 1200 mm / min, the single-pass transverse amount is 1.2 mm, the overlap rate is 40%, the powder feeding amount is 25 g / min, the protective gas flow is 20 L / min, the powder feeding gas flow is 8 L / min, and the protective gas is argon.

[0059] Step 5: The obtained cladded SiC ceramic reinforced copper-based wear-resistant coating is wiped with anhydrous ethanol, and then allowed to air dry naturally, and finally a copper-based alloy coating is prepared on the surface of the carbon steel substrate. Example 1

[0060] The preparation method of the carbon steel surface gradient copper coating of the embodiment comprises the following steps:

[0061] Steps 1-4 are the same as those of Comparative Example 2.

[0062] Step 5, ultrasonic rolling is performed on the outer surface of the cladded SiC ceramic reinforced copper-based wear-resistant coating (ultrasonic rolling equipment is used);

[0063] The specific conditions of ultrasonic rolling are as follows: the ultrasonic frequency is 25 kHz, the rolling pressure is 300 N, the rolling rate is 420 mm / min, the ultrasonic amplitude is 10 pm, the contact times are 4, and the processing temperature is room temperature.

[0064] Step 6, the cladded gradient copper-based coating after ultrasonic rolling is cleaned, and the carbon steel surface gradient copper coating is obtained after cleaning, and the structure is as shown in Figure 1 The carbon steel surface gradient copper coating comprises, from bottom to top, a carbon steel base 1, an inner layer 2 and an outer layer 3.

[0065] The specific conditions of cleaning are as follows: the surface of the cladded gradient copper-based coating after ultrasonic rolling is wiped with anhydrous ethanol, and is naturally air-dried. Example 2

[0066] The preparation method of the carbon steel surface gradient copper coating of the embodiment comprises the following steps:

[0067] Steps 1-4 and Step 6 are the same as those of Example 1.

[0068] Step 5, ultrasonic rolling is performed on the outer surface of the cladded SiC ceramic reinforced copper-based wear-resistant coating (ultrasonic rolling equipment is used);

[0069] The specific conditions of ultrasonic rolling are as follows: the ultrasonic frequency is 30 kHz, the rolling pressure is 400 N, the rolling rate is 300 mm / min, the ultrasonic amplitude is 10 pm, the contact times are 4, and the processing temperature is room temperature.

[0070] The electron micrograph of the microstructure of the interface between the inner layer and the carbon steel base after ultrasonic rolling in Example 2 is as shown in Figure 2 It can be observed that the interface is uniform and dense, has no pores, no inclusions, no cracks, and the cladding condition is good.

[0071] The electron micrograph of the microstructure of the interface between the outer layer and the inner layer after ultrasonic rolling in Example 2 is as shown in Figure 3 It can be observed that the interface is uniform and dense, has no pores, no inclusions, no cracks, and the cladding condition is good.

[0072] The electron micrograph of the microstructure of the outer layer after ultrasonic rolling in Example 2 is as shown in Figure 4As shown, it can be observed that the ceramic particles are evenly distributed and well mixed, and there are no holes, inclusions or cracks inside, and the cladding is in good condition.

[0073] The surface hardness comparison of the copper-based wear-resistant coatings obtained in Comparative Examples 1-2 and Examples 1-2 is shown in FIG. Figure 5 As shown, it can be seen that the hardness measurement value of Comparative Example 2 is significantly improved compared with Comparative Example 1, reflecting the enhancement effect of the outer layer SiC ceramic cladding reinforced copper-based wear-resistant coating; Example 1, based on Comparative Example 2, adopts ultrasonic rolling technology for treatment, and its hardness measurement value once again achieves a breakthrough growth, verifying the synergistic effect of ultrasonic rolling to form a tissue gradient copper coating; Example 2 further optimizes the technical parameters, and the hardness measurement value is optimal. Example 3

[0074] The method for preparing a gradient copper coating on a carbon steel surface according to the present embodiment comprises the following steps:

[0075] Step 1 is different from Example 1 in that: the copper-based alloy cladding powder is pretreated, the ultrasonic cleaning time is 4 minutes, and the drying temperature is 130°C.

[0076] Step 2 is different from Example 1 in that the mass ratio of the pretreated copper-based alloy cladding powder to the pretreated SiC ceramic particles is 19:1.

[0077] Step 3 is different from Example 1 in that the inner layer cladding parameters are set, including: laser power of 1500 W, scanning rate of 800 mm / min, single-pass lateral displacement of 1.0 mm, overlap rate of 40%, powder feeding amount of 15 g / min, shielding gas flow rate of 15 L / min, and powder feeding gas flow rate of 6 L / min.

[0078] Step 4 is different from Example 1 in that the outer layer cladding parameters are set, including: laser power of 1300 W, scanning rate of 800 mm / min, single-pass lateral displacement of 1.0 mm, overlap rate of 40%, powder feeding amount of 15 g / min, shielding gas flow rate of 15 L / min, and powder feeding gas flow rate of 6 L / min.

[0079] Step 5 is different from Example 1 in that the specific conditions of ultrasonic rolling are: ultrasonic frequency of 28 kHz, rolling pressure of 350 N, rolling rate of 400 mm / min, ultrasonic amplitude of 8 μm, number of contacts of 3 times, and processing temperature of room temperature. Example 4

[0080] The method for preparing a gradient copper coating on a carbon steel surface according to the present embodiment comprises the following steps:

[0081] Step 1 is different from Example 1 in that: the copper-based alloy cladding powder is pretreated, the ultrasonic cleaning time is 5 minutes, and the drying temperature is 150°C.

[0082] Step 2 is different from Example 1 in that the mass ratio of the pretreated copper-based alloy cladding powder to the pretreated SiC ceramic particles is 23:2.

[0083] Step 3 is different from Example 1 in that the inner layer cladding parameters are set, including: laser power of 1800 W, scanning rate of 1500 mm / min, single-pass lateral displacement of 1.5 mm, overlap rate of 40%, powder feeding amount of 20 g / min, shielding gas flow rate of 30 L / min, and powder feeding gas flow rate of 10 L / min.

[0084] Step 4 is different from Example 1 in that the outer layer cladding parameters are set, including: laser power of 1500 W, scanning rate of 1500 mm / min, single-pass lateral displacement of 1.5 mm, overlap rate of 40%, powder feeding amount of 20 g / min, shielding gas flow rate of 30 L / min, and powder feeding gas flow rate of 10 L / min.

[0085] Step 5 is different from Example 1 in that the specific conditions of ultrasonic rolling are: ultrasonic frequency of 26 kHz, rolling pressure of 380 N, rolling rate of 350 mm / min, ultrasonic amplitude of 12 μm, number of contacts of 6 times, and processing temperature of room temperature.

[0086] The foregoing shows and describes the principal features and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations that come within the meaning and range of equivalents of the claims are intended to be embraced therein.

[0087] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for preparing a gradient copper coating on a carbon steel surface, characterized in that: The following steps are involved: Step 1: selecting copper-based alloy cladding powder, SiC ceramic particles, and carbon steel substrate, and pretreating the copper-based alloy cladding powder, SiC ceramic particles, and carbon steel substrate respectively; Step 2: using high-energy ball milling to fully mix the pretreated copper-based alloy cladding powder and the pretreated SiC ceramic particles in proportion to obtain a uniform SiC ceramic reinforced copper-based wear-resistant powder; Step 3: The inner layer adopts coaxial powder feeding method, sets inner layer cladding parameters, and uses ultra-high-speed laser cladding technology to clad the copper-based alloy cladding powder on the surface of the carbon steel substrate, and quickly cools it; Step 4: The outer layer adopts a coaxial powder feeding method, sets the outer layer cladding parameters, and uses ultra-high-speed laser cladding technology to clad the SiC ceramic reinforced copper-based wear-resistant powder obtained in step 2 on the outer surface of the inner layer, and waits for natural cooling to obtain a cladding SiC ceramic reinforced copper-based wear-resistant coating; Step 5, ultrasonic rolling is performed on the outer surface of the SiC ceramic reinforced copper-based wear-resistant coating; Step 6: Cleaning the cladding gradient copper-based coating after ultrasonic rolling to obtain the cladding gradient copper coating on the carbon steel surface.

2. The method for preparing a gradient copper coating on a carbon steel surface according to claim 1, wherein: The copper-based alloy cladding powder in step 1 comprises, by weight percentage, 58-60% copper, 19.5-21% nickel, 6% molybdenum, 4.8-5% iron, 4.8-5% cobalt, 1.8-2.1% chromium, and 3% silicon; In the step 1, the carbon steel substrate is made of 27SiMn alloy steel.

3. The method for preparing a gradient copper coating on a carbon steel surface according to claim 1 or 2, characterized in that: In the step 1, the copper-based alloy cladding powder, SiC ceramic particles, and carbon steel substrate are pretreated respectively, wherein the pretreatment of the copper-based alloy cladding powder is specifically as follows: the copper-based alloy cladding powder is sieved using a sieve to keep the particle size of the copper-based alloy cladding powder between 25 and 50 μm, ultrasonically cleaned in anhydrous ethanol for 3 to 5 minutes at an ultrasonic frequency of 100 kHz, and then dried at 120 to 150° C. for 10 minutes; The SiC ceramic particles are pretreated by using a sieve to screen the SiC ceramic particles so that the average particle size of the SiC ceramic particles is maintained at 8 μm, washing the SiC ceramic particles with deionized water and drying the SiC ceramic particles until the surface is dry. The pretreatment of the carbon steel substrate is specifically as follows: wiping the surface of the carbon steel substrate with anhydrous ethanol and waiting for it to dry naturally.

4. The method for preparing a gradient copper coating on a carbon steel surface according to claim 1, wherein: The mass ratio of the pretreated copper-based alloy cladding powder to the pretreated SiC ceramic particles in step 2 is 9-19:

1.

5. The method for preparing a gradient copper coating on a carbon steel surface according to claim 1 or 4, characterized in that: In step 2, the pre-treated copper-based alloy cladding powder and the pre-treated SiC ceramic particles are fully mixed in proportion by high-energy ball milling, specifically: The pretreated SiC ceramic particles and pretreated copper-based alloy cladding powder were loaded into a ball mill jar in proportion and placed in a high-energy ball mill. Zirconia balls were selected as the ball milling medium, the ball-to-material ratio was 8:1, the mixing time was set to 8 h, and the mixing speed was 1400 r / min to obtain uniform SiC ceramic reinforced copper-based wear-resistant powder.

6. The method for preparing a gradient copper coating on a carbon steel surface according to claim 1, wherein: In step 3, the inner layer cladding parameters are set, including: laser power of 1500~2000W, scanning rate of 800~1500mm / min, single-pass traverse amount of 1.0~1.5mm, overlap rate of 40%, powder feeding amount of 15~25g / min, shielding gas flow rate of 15~30L / min, and powder feeding gas flow rate of 6~10L / min.

7. The method for preparing a gradient copper coating on a carbon steel surface according to claim 1, wherein: In step 4, the outer layer cladding parameters are set, including: laser power of 1300~1800W, scanning rate of 800~1500mm / min, single-pass traverse amount of 1.0~1.5mm, overlap rate of 40%, powder feeding amount of 15~25g / min, shielding gas flow rate of 15~30L / min, and powder feeding gas flow rate of 6~10L / min.

8. The method for preparing a gradient copper coating on a carbon steel surface according to claim 1, wherein: The specific conditions of ultrasonic rolling in step 5 are: ultrasonic frequency of 25-30 kHz, rolling pressure of 300-400 N, rolling rate of 300-420 mm / min, ultrasonic amplitude of 8-12 μm, number of contacts of 3-6 times, and processing temperature of room temperature.

9. The method for preparing a gradient copper coating on a carbon steel surface according to claim 1, wherein: The specific conditions for cleaning in step 6 are: wiping the surface of the cladding gradient copper-based coating after ultrasonic rolling with anhydrous ethanol and naturally air-drying.

10. A carbon steel surface cladding gradient copper coating prepared according to the method for preparing a carbon steel surface cladding gradient copper coating according to any one of claims 1 to 9.

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