Carbon steel surface cladding gradient copper coating and preparation method thereof

Abstract

The invention belongs to the technical field of metal coatings, 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 binding force between the coating and the carbon steel and prolong the service life, the copper-based alloy composite wear-resistant coating with the internal structure gradient is prepared on the surface of a carbon steel matrix by utilizing an ultra-high-speed laser cladding technology and an ultrasonic rolling technology. The preparation method comprises the following steps: firstly, cladding copper-based alloy cladding powder serving as an inner layer on the surface of a carbon steel substrate, then cladding SiC ceramic reinforced copper-based wear-resistant powder serving as an outer layer on the inner layer, carrying out ultrasonic rolling treatment on the outer layer, and finally, cleaning to obtain the carbon steel surface cladding gradient copper coating.

Description

Technical Field

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

[0002] Due to its good mechanical properties, low cost and wide availability of resources, carbon steel materials have been widely used in manufacturing, construction and mechanical engineering. However, carbon steel materials also have some inherent defects, such as poor corrosion resistance and limited wear resistance. Especially in humid and corrosive environments, they are prone to defects such as wear and rust, which seriously affect the service life of mechanical equipment and components and cause economic losses.

[0003] As common surface coating preparation technologies, electroplating and spraying mainly rely on physical bonding. The bonding force between the coating and the carbon steel substrate is weak, prone to wear, and prone to peeling and delamination under the action of stress or thermal stress. The coating life is short and it can no longer meet the requirements in many complex working conditions. At the same time, the chemical electrolyte in the electroplating process pollutes the environment to a certain extent, while the dust and waste in spraying are easy to pollute the air and are gradually replaced under the current environmental policies in the fields of energy conservation, emission reduction and green building.

[0004] The ultra-high speed laser cladding technology is a technology that melts and deposits the coating material on the surface of the substrate through a high heat source. Its advantage lies in that it can ensure good metallurgical bonding between the coating and the substrate while maintaining a low dilution rate and obtaining a fine and dense microstructure, effectively improving the specific performance of the part surface and extending the service life of the part. It has been widely used in fields such as mechanical manufacturing, aerospace, and petrochemical industry.

[0005] The existing laser cladding coating materials are mainly iron-based and cobalt-based. However, iron-based coatings are prone to many defects during the preparation process, resulting in a decline in the performance and reliability of the coatings. Cobalt-based coatings have poor mechanical properties and are also relatively expensive, not suitable for large-scale industrial production. In contrast, copper-based coatings not only have excellent thermal conductivity, electrical conductivity and corrosion resistance, but also have good wear resistance, providing a more economical and practical solution for the 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 usually have extremely high hardness. When added to the copper-based coating, they can significantly improve the overall hardness and wear resistance of the coating. However, at the same time, there will inevitably be a large difference in performance between the coating and the carbon steel material, which is likely to cause interface defects or stress concentration. Therefore, forming a transition region by adjusting the overall structure, gradually transitioning from the carbon steel material to the ceramic-reinforced copper-based coating, and simultaneously performing surface re-strengthening on the ceramic-reinforced copper-based coating is a new idea to improve defects and enhance the overall stability and surface performance of the coating. Summary of the Invention

[0007] To solve the above problems, the purpose of the present invention is to provide a gradient copper coating cladded on the surface of carbon steel and its preparation method. It uses copper-based coating materials to clad the surface of the carbon steel substrate. The inner layer is copper-based alloy cladding powder, and the outer layer is SiC ceramic-reinforced copper-based wear-resistant powder. The ultrasonic rolling technology is used to perform surface treatment on the cladded coating to form a tissue gradient. This gradient coating not only has excellent thermal conductivity and corrosion resistance, but also has good lubrication and a low friction coefficient, effectively improving the wear resistance of the surface of equipment and parts. At the same time, it can also avoid the occurrence of key problems such as cracking and severe deformation between materials.

[0008] To achieve the above purpose, the present invention adopts the following technical solutions: On the one hand, the present invention provides a preparation method for a gradient copper coating cladded on the surface of carbon steel, including the following steps: Step 1, select copper-based alloy cladding powder, SiC ceramic particles, and carbon steel substrate, and perform pretreatment on the copper-based alloy cladding powder, SiC ceramic particles, and carbon steel substrate respectively; Step 2, use high-energy ball milling to fully mix the pretreated copper-based alloy cladding powder and the pretreated SiC ceramic particles in proportion to obtain uniform SiC ceramic-reinforced copper-based wear-resistant powder; Step 3, adopt coaxial powder feeding for the inner layer, set the inner layer cladding parameters, and use ultra-high-speed laser cladding technology to clad the copper-based alloy cladding powder on the surface of the carbon steel substrate and rapidly cool it; Step 4, adopt coaxial powder feeding for the outer layer, set the outer layer cladding parameters, and use 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 wait for natural cooling to obtain a cladded SiC ceramic-reinforced copper-based wear-resistant coating; Step 5, perform ultrasonic rolling on the outer surface of the cladded SiC ceramic-reinforced copper-based wear-resistant coating; Step 6, clean the cladded gradient copper-based coating after ultrasonic rolling, and obtain the gradient copper coating cladded on the surface of carbon steel after cleaning.

[0009] Further, in the step 1, the copper-based alloy cladding powder, by weight percentage, comprises 58-60% of copper, 19.5-21% of nickel, 6% of molybdenum, 4.8-5% of iron, 4.8-5% of cobalt, 1.8-2.1% of chromium, and 3% of silicon; In the step 1, the carbon steel substrate is made of 27SiMn alloy steel.

[0010] Further, in the step 1, the copper-based alloy cladding powder, SiC ceramic particles, and carbon steel substrate are pretreated respectively. Among them, the pretreatment of the copper-based alloy cladding powder is specifically as follows: The copper-based alloy cladding powder is screened using a sieve to keep the particle size of the copper-based alloy cladding powder between 25 and 50 μm, then put into absolute ethanol for ultrasonic cleaning for 3-5 min, with an ultrasonic frequency of 100 kHz, and then dried at 120-150 °C for 10 min; surface impurities and oil stains are removed to prevent pores and cracks from being generated during the cladding process, ensure the cleanliness of the bonding interface between the copper-based alloy cladding powder and the carbon steel substrate, improve the wettability of the copper-based alloy cladding powder and the carbon steel substrate, and enhance the bonding force; Among them, the pretreatment of the SiC ceramic particles is specifically as follows: The SiC ceramic particles are screened using a sieve to keep the average particle size of the SiC ceramic particles at 8 μm, and then cleaned with deionized water and dried until the surface is dry; Among them, the pretreatment of the carbon steel substrate is specifically as follows: The surface of the carbon steel substrate is wiped with absolute ethanol and left to air dry naturally.

[0011] Further, in the step 2, the mass ratio of the copper-based alloy cladding powder to the SiC ceramic particles is 9-19:1.

[0012] Further, in the step 2, the pretreated copper-based alloy cladding powder and the pretreated SiC ceramic particles are fully mixed in proportion by means of high-energy ball milling. Specifically: The pretreated SiC ceramic particles and the pretreated copper-based alloy cladding powder are loaded into a ball milling tank in proportion and placed in a high-energy ball mill. Zirconia balls are selected as the ball milling medium, the ball-to-powder ratio is 8:1, the mixing time is set to 8 h, and the mixing rotation speed is 1400 r / min to obtain uniform SiC ceramic-reinforced copper-based wear-resistant powder.

[0013] Further, in the step 3, the inner layer cladding parameters are set, including: laser power of 1500-2000 W, scanning speed of 800-1500 mm / min, single-pass lateral displacement of 1.0-1.5 mm, overlap rate of 40%, powder feeding rate of 15-25 g / min, protective gas flow rate of 15-30 L / min, and powder feeding gas flow rate of 6-10 L / min.

[0014] Further, in step 4, the outer layer cladding parameters are set, including: laser power of 1300 - 1800 W, scanning rate of 800 - 1500 mm / min, single-pass lateral displacement of 1.0 - 1.5 mm, overlapping rate of 40%, powder feeding rate of 15 - 25 g / min, protective gas flow rate of 15 - 30 L / min, and powder feeding gas flow rate of 6 - 10 L / min.

[0015] Further, the specific conditions for 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 contact times of 3 - 6 times, and processing temperature at room temperature.

[0016] Further, the specific conditions for cleaning in step 6 are: wiping the surface of the clad gradient copper-based coating after ultrasonic rolling with anhydrous ethanol and air drying naturally.

[0017] On the other hand, the present invention also provides a carbon steel surface clad gradient copper coating prepared by the method for preparing a carbon steel surface clad gradient copper coating as described above.

[0018] Compared with the prior art, the present invention has the following advantages: 1. The present invention adopts a clad preparation method with a copper-based alloy clad powder as the inner layer for transition, which has the following advantages: the introduction of the transition layer can reduce the large differences in thermal expansion coefficient and physical properties between the outer layer clad SiC ceramic-reinforced copper-based wear-resistant coating and the carbon steel substrate, effectively relieve the stress concentration between the clad SiC ceramic-reinforced copper-based wear-resistant coating and the carbon steel substrate, and at the same time can also prevent cracks or delamination of the clad SiC ceramic-reinforced copper-based wear-resistant coating due to thermal stress during the cladding process or subsequent use, thereby improving the bonding strength between the overall wear-resistant coating and the substrate surface.

[0019] 2. The present invention uses ultrasonic rolling technology to perform surface treatment on the prepared clad SiC ceramic-reinforced copper-based wear-resistant coating, forming a tissue gradient with gradually refined grains from the inside to the outside surface within the wear-resistant coating, effectively increasing the surface hardness and wear resistance, improving the surface density and uniformity to enhance the corrosion resistance, improving the fatigue resistance of the wear-resistant coating by introducing surface compressive stress, extending the service life, and at the same time being able to reduce the surface roughness, making the surface smoother, and further promoting the wear resistance.

[0020] 3. The present invention realizes the effective combination of the ultra-high speed laser cladding technology and the ultrasonic rolling technology. By means of the ultra-high speed laser cladding technology, the copper-based alloy cladding powder is cladded on the outer surface of the carbon steel matrix, so as to form a good metallurgical bond between the inner copper-based coating and the carbon steel matrix. At the same time, the ultrasonic rolling technology is carried out on the surface of the cladded SiC ceramic-reinforced copper-based wear-resistant coating. It can not only improve the wear resistance of the surface of the cladded SiC ceramic-reinforced copper-based wear-resistant coating and reduce the roughness, but also the ultrasonic vibration during the ultrasonic rolling process can reduce the residual stress on the surface and inside of the material caused by the ultra-high speed laser cladding technology. In particular, it can effectively relieve the thermal stress difference between the carbon steel matrix and copper, enhance the bonding strength between the inner copper-based coating and the carbon steel matrix, and further improve the overall adhesion of the coating. At the same time, while increasing the hardness, the risk of coating rupture caused by stress concentration is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of the gradient copper coating cladded on the surface of the carbon steel prepared in Examples 1 and 2.

[0022] Figure 2 Electron micrograph of the microstructure of the connection interface between the inner layer and the carbon steel matrix after ultrasonic rolling in Example 2.

[0023] Figure 3 Electron micrograph of the microstructure of the connection interface between the outer layer and the inner layer after ultrasonic rolling in Example 2.

[0024] Figure 4 Electron micrograph of the microstructure of the outer layer after ultrasonic rolling in Example 2.

[0025] Figure 5 Comparison chart of the surface hardness of the copper-based wear-resistant coatings prepared in Comparative Examples 1-2 and Examples 1-2.

[0026] Wherein, 1 is the carbon steel matrix, 2 is the inner layer, and 3 is the outer layer. DETAILED DESCRIPTION OF THE INVENTION

[0027] In order to further elaborate the technical solution of the present invention, the present invention will be further described below through examples.

[0028] Comparative Example 1 This comparative example adopts a preparation method for an ultra-high speed laser cladded copper-based alloy coating, including the following steps: Step 1, select copper-based alloy cladding powder and carbon steel matrix. The copper-based alloy cladding powder, by weight percentage, includes 59% copper, 20% nickel, 6% molybdenum, 5% iron, 5% cobalt, 2% chromium, and 3% silicon. The carbon steel matrix is made of 27SiMn alloy steel; The copper-based alloy cladding powder is pretreated as follows: The copper-based alloy cladding powder is screened using a sieve to keep the particle size of the powder between 25 and 50 μm, then put into absolute ethanol for ultrasonic cleaning for 3 min with an ultrasonic frequency of 100 kHz, and then the powder is placed in a drying oven at 120 °C for drying treatment for 10 min; The carbon steel substrate is pretreated as follows: The surface of the 27SiMn alloy steel substrate is wiped with absolute ethanol and waited to air dry naturally.

[0029] Step 2, Laser cladding of the copper-based alloy coating is carried out by means of coaxial powder feeding (using a laser cladding device), and the laser cladding parameters are set as follows: the laser power is 2500 W, the scanning speed is 800 mm / min, the single-pass lateral displacement is 1.2 mm, the overlapping rate is 40%, the powder feeding rate is 30 g / min, the protective gas flow rate is 25 L / min, and the 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 waited to cool naturally.

[0030] Step 3, The obtained copper-based alloy coating is wiped with absolute ethanol and waited to air dry naturally, and finally a copper-based alloy coating is prepared on the surface of the carbon steel substrate.

[0031] Comparative Example 2 This comparative example adopts a preparation method for a copper-based alloy coating by ultra-high speed laser cladding, including the following steps: Step 1, Select copper-based alloy cladding powder, SiC ceramic particles, and a carbon steel substrate. The copper-based alloy cladding powder, by weight percentage, includes 59% copper, 20% nickel, 6% molybdenum, 5% iron, 5% cobalt, 2% chromium, and 3% silicon. The carbon steel substrate is 27SiMn alloy steel; The copper-based alloy cladding powder is pretreated as follows: The copper-based alloy cladding powder is screened using a sieve to keep the particle size of the powder between 25 and 50 μm, then put into absolute ethanol for ultrasonic cleaning for 3 min with an ultrasonic frequency of 100 kHz, and then the powder is placed in a drying oven at 120 °C for drying treatment for 10 min; The SiC ceramic particles are pretreated as follows: The SiC ceramic particles are screened using a sieve to keep the average particle size of the SiC ceramic particles at 8 μm, washed with deionized water, and then placed in a drying oven at 120 °C for drying treatment for 10 min; The carbon steel substrate is pretreated as follows: The surface of the 27SiMn alloy steel substrate is wiped with absolute ethanol and waited to air dry naturally.

[0032] Step 2, The pretreated copper-based alloy cladding powder and the pretreated SiC ceramic particles are fully mixed in proportion by means of high-energy ball milling to obtain uniform SiC ceramic-reinforced copper-based wear-resistant powder; Specifically, the pre-treated SiC ceramic particles and the pre-treated copper-based alloy cladding powder are weighed according to a mass ratio of 1:9, put into a ball milling tank, and placed in a high-energy ball mill. Zirconia balls are selected as the ball milling medium, the ball-to-powder ratio is 8:1, the mixing time is set to 8 h, the mixing rotation speed is 1400 r / min, and a uniform SiC ceramic-reinforced copper-based wear-resistant powder is obtained after sufficient mixing.

[0033] Step 3: The inner layer adopts a 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 rapidly cooled. The inner layer cladding parameters are set, including: laser power of 2000 W, scanning speed of 1200 mm / min, single-pass lateral displacement of 1.2 mm, overlap rate of 40%, powder feeding rate of 25 g / min, protective gas flow rate of 20 L / min, powder feeding gas flow rate of 8 L / min, and argon is selected as the protective gas.

[0034] Step 4: The outer layer adopts a 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 after natural cooling, a cladded SiC ceramic-reinforced copper-based wear-resistant coating is obtained. The outer layer cladding parameters are set, including: laser power of 1800 W, scanning speed of 1200 mm / min, single-pass lateral displacement of 1.2 mm, overlap rate of 40%, powder feeding rate of 25 g / min, protective gas flow rate of 20 L / min, powder feeding gas flow rate of 8 L / min, and argon is selected as the protective gas.

[0035] Step 5: The obtained cladded SiC ceramic-reinforced copper-based wear-resistant coating is wiped with anhydrous ethanol and left to air dry naturally, and finally a copper-based alloy coating is prepared on the surface of the carbon steel substrate. Example 1

[0036] A method for preparing a gradient copper coating on the surface of carbon steel in this example includes the following steps: Steps 1 to 4 are the same as those in Comparative Example 2.

[0037] Step 5: The outer surface of the cladded SiC ceramic-reinforced copper-based wear-resistant coating is subjected to ultrasonic rolling (using an ultrasonic rolling device). The specific conditions for ultrasonic rolling are: ultrasonic frequency of 25 kHz, rolling pressure of 300 N, rolling speed of 420 mm / min, ultrasonic amplitude of 10 μm, number of contact times of 4 times, and processing temperature of normal temperature.

[0038] Step 6: The ultrasonically rolled gradient copper-based coating is cleaned, and the gradient copper coating on the surface of the carbon steel is obtained after cleaning, and the structure is as Figure 1As shown, it includes a carbon steel substrate 1, an inner layer 2, and an outer layer 3 from bottom to top; The specific cleaning conditions are as follows: wipe the surface of the clad gradient copper-based coating after ultrasonic rolling with anhydrous ethanol and air dry it naturally. Example 2

[0039] A preparation method of a clad gradient copper coating on a carbon steel surface in this example includes the following steps: Steps 1 to 4 and Step 6 are the same as those in Example 1.

[0040] Step 5: Perform ultrasonic rolling on the outer surface of the clad SiC ceramic-reinforced copper-based wear-resistant coating (using ultrasonic rolling equipment); 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 μm, the number of contact times is 4 times, and the processing temperature is room temperature.

[0041] The electron micrograph of the microstructure of the connection interface between the inner layer and the carbon steel substrate after ultrasonic rolling in Example 2 is as Figure 2 shown. It can be observed that the connection interface is uniform and dense, without pores, inclusions, or cracks, and the cladding condition is good.

[0042] The electron micrograph of the microstructure of the connection interface between the outer layer and the inner layer after ultrasonic rolling in Example 2 is as Figure 3 shown. It can be observed that the connection interface is uniform and dense, without pores, inclusions, or cracks, and the cladding condition is good.

[0043] The electron micrograph of the microstructure of the outer layer after ultrasonic rolling in Example 2 is as Figure 4 shown. It can be observed that the ceramic particles are evenly distributed, the mixing condition is good, and there are no pores, inclusions, or cracks inside, and the cladding condition is good.

[0044] The surface hardness comparison diagram of the copper-based wear-resistant coatings prepared in Comparative Examples 1 to 2 and Examples 1 to 2 is as Figure 5 shown. It can be seen that the measured hardness value of Comparative Example 2 shows a significant increase compared to Comparative Example 1, reflecting the strengthening effect of the outer layer clad SiC ceramic-reinforced copper-based wear-resistant coating; based on Comparative Example 2, Example 1 uses ultrasonic rolling technology for treatment, and its measured hardness value achieves a breakthrough growth again, verifying the synergistic effect of ultrasonic rolling to form a tissue gradient copper coating; through further optimizing the technical parameters in Example 2, the measured hardness value is in the optimal state. Example 3

[0045] A preparation method of a clad gradient copper coating on a carbon steel surface in this example includes the following steps: Step 1, different from Example 1: The copper-based alloy cladding powder is pretreated, the ultrasonic cleaning time is 4 min, and the drying temperature is 130 °C.

[0046] Step 2, different from Example 1: The mass ratio of the pretreated copper-based alloy cladding powder to the pretreated SiC ceramic particles is 19:1.

[0047] Step 3, different from Example 1: The inner layer cladding parameters are set, including: laser power is 1500 W, scanning speed is 800 mm / min, single-pass transverse shift is 1.0 mm, overlapping rate is 40%, powder feeding rate is 15 g / min, protective gas flow rate is 15 L / min, and powder feeding gas flow rate is 6 L / min.

[0048] Step 4, different from Example 1: The outer layer cladding parameters are set, including: laser power is 1300 W, scanning speed is 800 mm / min, single-pass transverse shift is 1.0 mm, overlapping rate is 40%, powder feeding rate is 15 g / min, protective gas flow rate is 15 L / min, and powder feeding gas flow rate is 6 L / min.

[0049] Step 5, different from Example 1: The specific conditions of ultrasonic rolling are: ultrasonic frequency is 28 kHz, rolling pressure is 350 N, rolling speed is 400 mm / min, ultrasonic amplitude is 8 μm, contact times are 3 times, and the processing temperature is room temperature. Example 4

[0050] A preparation method of a gradient copper coating on the surface of carbon steel in this example includes the following steps: Step 1, different from Example 1: The copper-based alloy cladding powder is pretreated, the ultrasonic cleaning time is 5 min, and the drying temperature is 150 °C.

[0051] Step 2, different from Example 1: The mass ratio of the pretreated copper-based alloy cladding powder to the pretreated SiC ceramic particles is 23:2.

[0052] Step 3, different from Example 1: The inner layer cladding parameters are set, including: laser power is 1800 W, scanning speed is 1500 mm / min, single-pass transverse shift is 1.5 mm, overlapping rate is 40%, powder feeding rate is 20 g / min, protective gas flow rate is 30 L / min, and powder feeding gas flow rate is 10 L / min.

[0053] Step 4, which is different from Embodiment 1 in that: the outer layer cladding parameters are set, including: laser power of 1500 W, scanning speed of 1500 mm / min, single-pass transverse displacement of 1.5 mm, overlapping rate of 40%, powder feeding rate of 20 g / min, protective gas flow rate of 30 L / min, and powder feeding gas flow rate of 10 L / min.

[0054] Step 5, which is different from Embodiment 1 in that: the specific conditions of ultrasonic rolling are: ultrasonic frequency of 26 kHz, rolling pressure of 380 N, rolling speed of 350 mm / min, ultrasonic amplitude of 12 μm, number of contact times of 6 times, and processing temperature of normal temperature.

[0055] The foregoing has shown and described the main features and advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes that fall within the meaning and scope of the equivalent elements of the claims in the present invention.

[0056] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a gradient copper coating by cladding on the surface of carbon steel, characterized in that, It includes the following steps: Step 1: Select a copper-based alloy clad powder, SiC ceramic particles, and a carbon steel substrate, and perform pretreatment on the copper-based alloy clad powder, SiC ceramic particles, and carbon steel substrate respectively; Step 2: Adopt a high-energy ball milling method to fully mix the pretreated copper-based alloy clad powder and the pretreated SiC ceramic particles in proportion to obtain a uniform SiC ceramic-reinforced copper-based wear-resistant powder; Step 3: Use a coaxial powder feeding method for the inner layer, set the inner layer cladding parameters, and use the ultra-high-speed laser cladding technology to clad the copper-based alloy clad powder on the surface of the carbon steel substrate and rapidly cool it; Step 4: Use a coaxial powder feeding method for the outer layer, set the outer layer cladding parameters, and use the 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 wait for natural cooling to obtain a clad SiC ceramic-reinforced copper-based wear-resistant coating; Step 5: Perform ultrasonic rolling on the outer surface of the clad SiC ceramic-reinforced copper-based wear-resistant coating; Step 6: Clean the clad gradient copper-based coating after ultrasonic rolling, and obtain the clad gradient copper coating on the surface of the carbon steel after cleaning.

2. The preparation method of a gradient copper coating by cladding on the surface of carbon steel according to claim 1, wherein, In Step 1, the copper-based alloy clad powder, by weight percentage, includes 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 Step 1, the carbon steel substrate is selected as 27SiMn alloy steel.

3. A method for preparing a gradient copper coating by cladding on the surface of carbon steel according to claim 1 or 2, characterized in that, In Step 1, pretreatment is performed on the copper-based alloy clad powder, SiC ceramic particles, and carbon steel substrate respectively. Among them, the pretreatment of the copper-based alloy clad powder is specifically: use a sieve to screen the copper-based alloy clad powder to keep the particle size of the copper-based alloy clad powder between 25 and 50 μm, put it into absolute ethanol for ultrasonic cleaning for 3-5 min, the ultrasonic frequency is 100 kHz, and then place it at 120-150 °C for drying treatment for 10 min; Among them, the pretreatment of the SiC ceramic particles is specifically: use a sieve to screen the SiC ceramic particles to keep the average particle size of the SiC ceramic particles at 8 μm, clean them with deionized water and dry them until the surface is dry; Among them, the pretreatment of the carbon steel substrate is specifically: wipe the surface of the carbon steel substrate with absolute ethanol and wait for natural air drying.

4. The preparation method of a gradient copper coating by surface melting on carbon steel according to claim 1, characterized in that, In Step 2, the mass ratio of the pretreated copper-based alloy clad powder to the pretreated SiC ceramic particles is 9-19:

1.

5. The preparation method of a gradient copper coating by surface cladding on carbon steel according to claim 1 or 4, characterized in that, In Step 2, the high-energy ball milling method is used to fully mix the pretreated copper-based alloy clad powder and the pretreated SiC ceramic particles in proportion, specifically: Load the pretreated SiC ceramic particles and the pretreated copper-based alloy clad powder into the ball milling tank in proportion, place it in a high-energy ball mill, select zirconia balls as the ball milling medium, the ball-to-material ratio is 8:1, set the mixing time to 8 h, and the mixing speed to 1400 r / min to obtain a uniform SiC ceramic-reinforced copper-based wear-resistant powder.

6. The preparation method of a gradient copper coating by cladding on the surface of carbon steel according to claim 1, characterized in that, In step 3, the inner layer cladding parameters are set, including: laser power of 1500 - 2000 W, scanning speed of 800 - 1500 mm / min, single-pass lateral displacement of 1.0 - 1.5 mm, overlapping rate of 40%, powder feeding rate of 15 - 25 g / min, protective gas flow rate of 15 - 30 L / min, and powder feeding gas flow rate of 6 - 10 L / min.

7. A method for preparing a gradient copper coating on the surface of carbon steel according to claim 1, characterized in that, In step 4, the outer layer cladding parameters are set, including: laser power of 1300 - 1800 W, scanning speed of 800 - 1500 mm / min, single-pass lateral displacement of 1.0 - 1.5 mm, overlapping rate of 40%, powder feeding rate of 15 - 25 g / min, protective gas flow rate of 15 - 30 L / min, and powder feeding gas flow rate of 6 - 10 L / min.

8. The preparation method of a gradient copper coating by surface melting on a carbon steel according to claim 1, characterized in that, In step 5, the specific conditions for ultrasonic rolling are: ultrasonic frequency of 25 - 30 kHz, rolling pressure of 300 - 400 N, rolling speed of 300 - 420 mm / min, ultrasonic amplitude of 8 - 12 μm, contact times of 3 - 6 times, and processing temperature at room temperature.

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

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

Images