Iron-based wear-resistant corrosion-resistant coating for marine environment and preparation method of iron-based wear-resistant corrosion-resistant coating

Abstract

The invention discloses an iron-based wear-resistant and corrosion-resistant coating for a marine environment and a preparation method of the iron-based wear-resistant and corrosion-resistant coating, the method comprises the steps that composite powder is prepared from wear-resistant powder and corrosion-resistant powder, the wear-resistant powder comprises the following chemical components in percentage by weight: 1.9-2.2 wt% of C, 8-10 wt% of V, 4.5-5.2 wt% of Cr, 0.8-1.2 wt% of Mo and 0.4-0.6 wt% of Mn, and the corrosion-resistant powder comprises the following chemical components in percentage by weight: 0.2-0.3 wt% of C, 0.8-1.2 wt% of B, 17-19 wt% of Cr, 1.5-2 wt% of Ni, 0.8-1.1 wt% of Mo and 0.2-0.5 wt% of Mn; the wear-resistant powder and the corrosion-resistant powder are mixed according to the proportion of 1: (9-13) and are cladded on a base body through laser cladding. The wear-resistant powder and the corrosion-resistant powder with specific components are mixed, the proportion of the wear-resistant powder and the corrosion-resistant powder is regulated and controlled, laser cladding process parameters are optimized and controlled, and the iron-based coating which has wear resistance and corrosion resistance and is strongly metallurgically bonded is obtained.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of surface treatment of metal materials, and particularly relates to an iron-based wear-resistant and corrosion-resistant coating for marine environment and a preparation method thereof. BACKGROUND

[0002] Various gate valves in the marine machinery, coal chemical industry and petroleum industry, various sand pumps, slurry pumps, water turbines and conveying pipelines in the mining and cement industries work in complex and harsh wear and corrosion environments. The service life of these workpieces is greatly shortened due to the unsatisfactory protective coating materials and properties of the workpiece surfaces, which not only brings safety hazards but also becomes the most consumed and easily damaged parts. The commonly used methods to improve the surface properties mainly include laser and plasma cladding, surfacing, double-metal composite casting or inlaying, spraying and the like, which can prepare different coatings on different metal material substrates to improve the wear resistance or corrosion resistance.

[0003] Chinese patent application with publication number CN110423540A discloses a preparation process of an anti-wear and anti-corrosion coating for an automobile chassis. The anti-wear and anti-corrosion coating prepared by the invention has greatly improved anti-wear and anti-corrosion performance compared with traditional chassis coatings, reduces the probability of chassis damage caused by stone impact or long-term corrosion, and thus ensures the service life of the automobile chassis.

[0004] Chinese patent with publication number CN115922149B discloses a high wear-resistant and corrosion-resistant laser cladding flux-cored wire and a preparation method thereof. The invention realizes the strength of the metal coating by adding C, Cr, Ni and Mo elements for solid solution strengthening, generating WC by CW reaction, and generating borides by B and C reaction. The combined strengthening adopted by the invention has better and more obvious strengthening effect than single alloy element strengthening, has high production efficiency, low cost and wide application prospect.

[0005] Chinese patent application with publication number CN118668205A discloses a high wear-resistant and corrosion-resistant mold steel surface cladding layer and a preparation method thereof. The invention regulates and adds Mo and Nb elements to synergistically enhance the performance of the mold surface cladding layer through solid solution strengthening and precipitation strengthening. The hardness of the mold surface cladding layer is improved by more than 500 HV-(0.2) compared with the base material, the wear resistance and corrosion resistance are both more than 15 times of the base material, the mold surface cladding layer is metallurgically combined with the base material, has high bonding strength and is not easy to fall off.

[0006] Chinese patent application with publication number CN102181857A discloses a method for preparing a seawater corrosion-resistant cladding layer on a steel substrate. The method uses a high-energy density laser beam to melt mixed powder and form an alloyed Ni-Cr-Mo corrosion-resistant cladding layer in situ on the surface of the steel substrate. The cladding layer is metallurgically combined with the base material, has low dilution rate, low preparation cost, long seawater corrosion-resistant service life of the cladding layer and simple process.

[0007] A Chinese patent with publication number CN116180078B discloses a steel surface corrosion and wear resistant composite coating and its preparation method and application, which solves the corrosion problem existing between the PVD coating and the steel surface, reduces the stress between the interfaces of different layers, and further enhances the bonding force between the PVD nitride coating and the base steel, thereby improving the corrosion and wear resistance of the steel surface composite coating.

[0008] A Chinese patent application with publication number CN119824337A discloses a high-strength wear-resistant martensitic stainless steel material and a preparation method thereof. The invention prepares a nano-scale precipitated phase by adding Cu, Al and Ni elements to the martensitic stainless steel and controlling the heat treatment process, so as to improve the strength and toughness and wear-resistant performance of the traditional stainless steel.

[0009] A Chinese patent application with publication number CN119243143A discloses a Nb-induced ultra-fine-grained Fe-based high-wear-resistant laser cladding layer and its cladding process. The average grain size of the cladding layer reaches a sub-micron ultra-fine grain size, and it shows high corrosion resistance. Compared with the 27SiMn base material, the wear-resistant performance is 7.3 times that of the 27SiMn base material. Due to the special ratio of the alloy powder, the alloy powder does not need to be too fine. The coaxial powder feeding method is used to perform laser cladding without forced cooling, and the process is simple.

[0010] The above different coating preparation methods can improve the service life of the workpiece. However, so far, there are few disclosures of strong metallurgical bonding iron-based coatings with wear-resistant and corrosion-resistant properties and their preparation methods through material organization and structure design and process implementation to meet the performance requirements of wear and corrosion in marine environment. Therefore, it is urgent to develop an iron-based wear-resistant and corrosion-resistant coating for marine environment and its preparation method to meet the higher wear-resistant and corrosion-resistant requirements of wear-resistant and corrosion-resistant materials and coatings in marine environment. SUMMARY

[0011] To solve the above-mentioned technical problems in the prior art, the present application provides an iron-based wear-resistant and corrosion-resistant coating for marine environment and a preparation method thereof.

[0012] In one aspect of the present application, the preparation method of the iron-based wear-resistant and corrosion-resistant coating for marine environment comprises the following steps:

[0013] The composite powder is prepared by mixing and drying abrasion-resistant powder and corrosion-resistant powder in a proportion, wherein the abrasion-resistant powder has a chemical composition controlled as follows in terms of mass percentage: C: 1.9-2.2wt%, V: 8-10wt%, Cr: 4.5-5.2wt%, Mo: 0.8-1.2wt%, Mn: 0.4-0.6wt%, and the balance of Fe; and the corrosion-resistant powder has a chemical composition controlled as follows in terms of mass percentage: C: 0.2-0.3wt%, B: 0.8-1.2wt%, Cr: 17-19wt%, Ni: 1.5-2wt%, Mo: 0.8-1.1wt%, Mn: 0.2-0.5wt%, and the balance of Fe.

[0014] The laser cladding is performed on the substrate to obtain the abrasion-resistant and corrosion-resistant coating, and the laser cladding process parameters are controlled as follows: laser power: 1500-2000W, spot diameter: 3-4mm, scanning speed: 10-15mm / s, and overlap rate: 45-55%.

[0015] Further, in the above method for preparing the iron-based abrasion-resistant and corrosion-resistant coating for marine environment, the proportion of the abrasion-resistant powder and the corrosion-resistant powder is controlled as follows: abrasion-resistant powder: corrosion-resistant powder = 1:(9-13).

[0016] Further, in the above method for preparing the iron-based abrasion-resistant and corrosion-resistant coating for marine environment, the particle size of the abrasion-resistant powder is controlled as 80-100μm.

[0017] Preferably, in the above method for preparing the iron-based abrasion-resistant and corrosion-resistant coating for marine environment, the chemical composition of the abrasion-resistant powder is controlled as follows in terms of mass percentage: C: 2wt%, V: 9wt%, Cr: 5wt%, Mo: 1wt%, Mn: 0.5wt%, and the balance of Fe; and the chemical composition of the corrosion-resistant powder is controlled as follows in terms of mass percentage: C: 0.2wt%, B: 1wt%, Cr: 18wt%, Ni: 2wt%, Mo: 1wt%, Mn: 0.3wt%, and the balance of Fe.

[0018] Further, in the above method for preparing the iron-based abrasion-resistant and corrosion-resistant coating for marine environment, the substrate surface is pretreated before the laser cladding step, which includes the following steps: firstly, the substrate surface is treated by using a grinding wheel, and then the substrate surface is polished flat by using sandpaper with mesh numbers of 400, 800 and 1200 in sequence, so as to remove oil stains and oxides and increase roughness; and then the substrate surface is degreased by using anhydrous ethanol and dried in air.

[0019] Further, in the above-mentioned method for preparing the iron-based wear-resistant and corrosion-resistant coating for marine environment, the specific implementation process of the laser cladding step is as follows: the substrate after surface pretreatment is placed on the workbench of the laser cladding equipment, the composite powder is spread on the substrate, the laser cladding equipment is operated to scan the spread composite powder on the substrate, and protective gas is introduced to protect the atmosphere.

[0020] Further, in the above-mentioned method for preparing the iron-based wear-resistant and corrosion-resistant coating for marine environment, the thickness of the prepared wear-resistant and corrosion-resistant coating is 0.8-1.5 mm.

[0021] Further, in the above-mentioned method for preparing the iron-based wear-resistant and corrosion-resistant coating for marine environment, the substrate is a Q355 steel substrate.

[0022] In another aspect of the present application, the provided iron-based wear-resistant and corrosion-resistant coating for marine environment is prepared by the above-mentioned method for preparing the iron-based wear-resistant and corrosion-resistant coating for marine environment, and the chemical composition of the iron-based wear-resistant and corrosion-resistant coating for marine environment is as follows: C: 0.33-0.38 wt%, V: 0.64-0.9 wt%, B: 0.9-0.93 wt%, Cr: 16.7-17.17 wt%, Ni: 1.8-1.86 wt%, Mo: 0.8-1.1 wt%, Mn: 0.31-0.32 wt%, and the balance of Fe.

[0023] Further, the surface hardness of the above-mentioned iron-based wear-resistant and corrosion-resistant coating for marine environment is ≥670 HV0.2.

[0024] The iron-based wear-resistant and corrosion-resistant coating for marine environment and the preparation method thereof have the following advantages and beneficial effects:

[0025] The present application mixes wear-resistant powder and corrosion-resistant powder with specific components, controls the ratio of wear-resistant powder and corrosion-resistant powder, uses laser cladding technology, and optimizes and controls the laser cladding process parameters to cladding the composite powder on the Q355 steel substrate, forms a wear-resistant and corrosion-resistant composite coating with complete metallurgical bonding, the C and B elements in the coating are solid solution strengthened in the substrate, and form hard phases such as M 23 C6, M7C3, M3C, etc., the high Cr content promotes the generation of a dense passivation film, and the hardness of the coating is ≥670 HV 0.2 , the wear resistance is improved by 3 times compared with the substrate, the corrosion current is reduced by two orders of magnitude, and the corrosion resistance is significantly improved. Thus, an iron-based coating with wear-resistant performance, corrosion-resistant performance, and strong metallurgical bonding can be obtained, which is suitable for surface strengthening of marine equipment, can improve the performance and service life of marine equipment, and solves the problem of contradictory performance requirements of wear and corrosion in marine environment in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only used to further understand the present application and form a part of the present application. All other drawings obtained by those skilled in the art without creative effort based on the drawings are within the scope of the present application.

[0027] Figure 1 is a schematic diagram of the cross-sectional structure of the iron-based wear-resistant and corrosion-resistant coating for marine environment of the present application;

[0028] Figure 2 is a morphology diagram of the composite powder used for the iron-based wear-resistant and corrosion-resistant coating for marine environment of the present application;

[0029] Figure 3 is an XRD diagram of the iron-based wear-resistant and corrosion-resistant coating for marine environment prepared in embodiments 1 and 2 of the present application;

[0030] Figure 4 is a microhardness diagram of the iron-based wear-resistant and corrosion-resistant coating for marine environment prepared in embodiments 1 and 2 of the present application;

[0031] Figure 5 is a wear track profile diagram of the iron-based wear-resistant and corrosion-resistant coating for marine environment prepared in embodiments 1 and 2 of the present application;

[0032] Figure 6 is a polarization curve diagram of the iron-based wear-resistant and corrosion-resistant coating for marine environment prepared in embodiments 1 and 2 of the present application;

[0033] Figure 7a and Figure 7b is an EIS diagram of the iron-based wear-resistant and corrosion-resistant coating for marine environment prepared in embodiments 1 and 2 of the present application. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the present application clearer, the following will describe the technical solutions of the present application in a clear and complete manner with reference to the specific embodiments of the present application and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of the present application.

[0035] The present application aims at the problem that wear resistance and corrosion resistance of iron-based coating are difficult to be coordinated in marine environment, and provides an iron-based wear-resistant and corrosion-resistant coating for marine environment and a preparation method thereof.The present application prepares a composite powder by mixing wear-resistant powder and corrosion-resistant powder in proportion, controls contents of Cr, V and C alloy elements, fully utilizes laser cladding technology to clad the composite powder on a Q355 steel substrate, and forms a wear-resistant and corrosion-resistant composite coating in complete metallurgical bonding, which fully meets the requirements of wear-resistant and corrosion-resistant materials and higher wear resistance and corrosion resistance of the coating in marine environment.

[0036] Specifically, the preparation method of the iron-based wear-resistant and corrosion-resistant coating for marine environment comprises the following steps:

[0037] (1) Composite powder preparation: the raw materials of the wear-resistant and corrosion-resistant coating are wear-resistant powder and corrosion-resistant powder, wherein the chemical composition of the wear-resistant powder is controlled as C: 1.9-2.2wt%, V: 8-10wt%, Cr: 4.5-5.2wt%, Mo: 0.8-1.2wt%, Mn: 0.4-0.6wt%, and the balance of Fe in terms of mass percentage, and the chemical composition of the corrosion-resistant powder is controlled as C: 0.2-0.3wt%, B: 0.8-1.2wt%, Cr: 17-19wt%, Ni: 1.5-2wt%, Mo: 0.8-1.1wt%, Mn: 0.2-0.5wt%, and the balance of Fe in terms of mass percentage, and the wear-resistant powder and the corrosion-resistant powder are mixed by a three-dimensional mixer according to the ratio of wear-resistant powder: corrosion-resistant powder = 1:(9-13), and the composite powder is prepared after drying.

[0038] (2) Substrate surface pretreatment: first, the surface of the Q355 steel substrate is treated by a grinding wheel to remove oil stains and oxides and increase roughness, and if it is used directly without removing, the quality of cladding will be affected, wherein in the grinding wheel grinding process, the surface of the Q355 steel substrate is polished flat by using 400 mesh, 800 mesh and 1200 mesh sandpaper in turn, and then the surface of the Q355 steel substrate is degreased by using anhydrous ethanol and dried in air.

[0039] (3) Laser cladding: the Q355 steel substrate after surface pretreatment is placed on the workbench of the laser cladding equipment, the composite powder is spread on the Q355 steel substrate, and the laser cladding equipment is operated to scan the spread composite powder on the Q355 steel substrate, while the protective gas is introduced for atmosphere protection, the composite powder is completely melted and solidified, and the wear-resistant and corrosion-resistant coating in complete metallurgical bonding is formed on the Q355 steel substrate, wherein the laser cladding process parameters are controlled as follows: laser power 1500-2000W, spot diameter 3-4mm, scanning speed 10-15mm / s, and overlap rate 45-55%.

[0040] According to the actual application requirements, the thickness of the wear-resistant and corrosion-resistant coating formed on the Q355 steel substrate is 0.8-1.5 mm.

[0041] In the marine environment iron-based wear-resistant and corrosion-resistant coating preparation method of the application, the chemical composition of the prepared wear-resistant and corrosion-resistant coating is C: 0.33-0.38 wt%, V: 0.64-0.9 wt%, B: 0.9-0.93 wt%, Cr: 16.7-17.17 wt%, Ni: 1.8-1.86 wt%, Mo: 0.8-1.1 wt%, Mn: 0.31-0.32 wt%, and the balance is Fe.

[0042] In the marine environment iron-based wear-resistant and corrosion-resistant coating preparation method of the application, by adjusting the different proportions of wear-resistant powder and corrosion-resistant powder, the content of Cr, V, B and C alloying elements in the coating can be changed, thereby the wear resistance and corrosion resistance of the coating can be controlled. Among them, the C and B elements are solid solution strengthened and form hard carbide boride phase, and high Cr content promotes the generation of dense passivation film, thereby improving the hardness and significantly improving the wear resistance and corrosion resistance.

[0043] In the marine environment iron-based wear-resistant and corrosion-resistant coating preparation method of the application, by optimizing the control of laser cladding process parameters, under the conditions of high and concentrated heat energy and capillary action in the molten pool, the molten pool temperature is high, the C and B elements act as interstitial atoms to play a solid solution strengthening effect, and are easy to form different carbides such as M 23 C6, M7C3, M3C, etc., to play a second phase strengthening effect, so that the surface hardness is ≥670 HV 0.2 , which greatly improves the hardness and wear resistance of the coating. At the same time, high Cr content makes it easier to generate a dense oxide film, improving the corrosion resistance of the material. Through the implementation of the application, the substrate deformation is small, the efficiency is high, the coating thickness is easy to control, the material composition is flexible and has a wide selection range, and it is suitable for fields such as marine engineering, mining, metallurgy, petroleum, power and chemical industry.

[0044] Therefore, the marine environment iron-based wear-resistant and corrosion-resistant coating preparation method of the application can form a rapid melting transition zone between the wear-resistant and corrosion-resistant composite coating and the substrate, and the hardness thereof is between the coating and the substrate, which is beneficial to improve the bonding force between the coating and the substrate; under suitable laser cladding process parameters, part of the contained reinforcing particles is dissolved and dispersed, and is firmly combined with the coating material through the surrounding epitaxial growth dendrites and is uniformly distributed in the cladding layer, thereby improving the surface hardness, wear resistance, coating bonding force and other properties of the coating, and the corrosion resistance is good. The cross-sectional structure of the marine environment iron-based wear-resistant and corrosion-resistant coating of the application is shown in Figure 1 ; by mixing two powders with different properties, the morphology of the mixed powder is as shown in Figure 2The wear-resistant and corrosion-resistant coating has high flexibility, can effectively save materials and energy, and is suitable for surface strengthening of marine equipment, thereby improving the service performance and service life of the marine equipment, reducing maintenance costs, and having great economic significance.

[0045] The marine environment iron-based wear-resistant and corrosion-resistant coating and the preparation method thereof will be further described below in combination with specific examples.

[0046] Example 1

[0047] The preparation method of the marine environment iron-based wear-resistant and corrosion-resistant coating of Example 1 comprises the following steps:

[0048] (1) Preparation of composite powder: The raw material of the wear-resistant and corrosion-resistant coating is wear-resistant powder and corrosion-resistant powder, wherein the chemical composition of the wear-resistant powder is controlled as C: 2wt%, V: 9wt%, Cr: 5wt%, Mo: 1wt%, Mn: 0.5wt%, and the balance of Fe in terms of mass percentage, and the particle size of the wear-resistant powder is controlled as 80-100 μm; the chemical composition of the corrosion-resistant powder is controlled as C: 0.2wt%, B: 1wt%, Cr: 18wt%, Ni: 2wt%, Mo: 1wt%, Mn: 0.3wt%, and the balance of Fe in terms of mass percentage, and the wear-resistant powder and the corrosion-resistant powder are mixed by a three-dimensional mixer according to the ratio of 1:9, and then the composite powder is prepared after drying.

[0049] (2) Surface pretreatment of the substrate: first, the surface of the Q355 steel substrate is treated by a grinding wheel, and the surface of the Q355 steel substrate is polished flat by using sandpaper with mesh numbers of 400, 800 and 1200 in sequence, so as to remove oil stains and oxides and increase roughness, and then the surface of the Q355 steel substrate is degreased by using anhydrous ethanol and dried in air.

[0050] (3) Laser cladding: the Q355 steel substrate after surface pretreatment is placed on the workbench of the laser cladding equipment, the composite powder is spread on the Q355 steel substrate, and the laser cladding equipment is operated to scan the spread composite powder on the Q355 steel substrate, while the protective gas is introduced to protect the atmosphere, the composite powder is completely melted and solidified, and the wear-resistant and corrosion-resistant composite coating in complete metallurgical bonding is formed on the Q355 steel substrate, wherein the laser cladding process parameters are controlled as follows: laser power 1800W, spot diameter 4mm, scanning speed 10mm / s, and overlap rate 50%.

[0051] In Example 1, the wear-resistant and corrosion-resistant coating with a thickness of 1.0-1.5mm is prepared on the Q355 steel substrate, and the chemical composition of the coating is C: 0.38wt%, V: 0.9wt%, B: 0.9wt%, Cr: 16.7wt%, Ni: 1.8wt%, Mo: 1wt%, Mn: 0.32wt%, and the balance of Fe in terms of mass percentage.

[0052] After the prepared workpiece with cladding coating is cooled to room temperature, the sample is cut into a suitable size by wire cutting, and after embedding, grinding, polishing and etching treatment, a reciprocating friction test is carried out under the test conditions of a mechanical load of 80 N, a wear rate of 6 mm / s and a wear frequency of 1 Hz, and an electrochemical test is carried out in a three-electrode system using an electrochemical workstation, so as to test the wear resistance and corrosion resistance of the coating of the embodiment 1 of the present application respectively. The above wear resistance and corrosion resistance tests are carried out in a simulated seawater solution containing 3.5 wt% chloride.

[0053] As shown in Figure 3 , the coating of the embodiment 1 exhibits diffraction peaks corresponding to the body-centered cubic (BCC) structure of α-Fe and the face-centered cubic (FCC) structure of γ-Fe, and weak diffraction peaks of M7C3, M3C and M 23 C6. As shown in Figure 4 , the average hardness of the workpiece surface of the embodiment 1 can reach 670 HV 0.2 , which is more than 3 times higher than the hardness of the Q355 steel substrate itself. Figure 5 The wear scar profile of the coating after the friction and wear test is shown, and it can be obviously seen that the wear scar width and depth of the coating of the embodiment 1 are smaller than those of Q355, and the wear resistance is improved. Figure 6 The potentiodynamic polarization curve of the coating is shown, and it can be seen that there is an obvious passivation interval for the coating of the embodiment 1. Figure 7a and Figure 7b The EIS graph of the coating is shown, wherein Figure 7a The Nyquist graph of the coating is shown, Figure 7b The Bode graph of the coating is shown. The EIS curve characterizes the electrochemical response of the substrate / electrolyte interface, and the Bode graph shows that the phase angle of the coating of the embodiment 1 is obviously larger than that of Q355 at low frequency, indicating that the passivation film on the surface of the coating of the embodiment 1 is more dense. The Nyquist graph shows that the capacity resistance arc is a single arc, and the arc radius of the coating of the embodiment 1 is larger than that of the Q355 substrate. According to Figure 6 and Figure 7a , 7b , the corrosion resistance of the coating of the embodiment 1 is significantly better than that of Q355. In Figure 3 , 4 , 5, 6, 7a, 7b, the coating of the embodiment 1 is indicated as "9-1".

[0054] Embodiment 2

[0055] The preparation method of the marine environment-resistant iron-based wear-resistant and corrosion-resistant coating of the embodiment 2 comprises the following steps:

[0056] (1) Composite powder preparation: The raw material of the wear-resistant and corrosion-resistant coating is wear-resistant powder and corrosion-resistant powder, wherein the chemical composition of the wear-resistant powder is controlled as follows in percentage by mass: C: 2wt%, V: 9wt%, Cr: 5wt%, Mo: 1wt%, Mn: 0.5wt%, and the balance of Fe, and the particle size of the wear-resistant powder is controlled as 80-100μm; the chemical composition of the corrosion-resistant powder is controlled as follows in percentage by mass: C: 0.2wt%, B: 1wt%, Cr: 18wt%, Ni: 2wt%, Mo: 1wt%, Mn: 0.3wt%, and the balance of Fe; the wear-resistant powder and the corrosion-resistant powder are mixed by a three-dimensional mixer according to the ratio of 1:13, and the composite powder is prepared after drying.

[0057] (2) Substrate surface pretreatment: The surface of the Q355 steel substrate is first treated by a grinding wheel, and the surface of the Q355 steel substrate is polished flat by using sandpaper with mesh numbers of 400, 800 and 1200 in sequence, so as to remove oil stains and oxides and increase roughness, and then the surface of the Q355 steel substrate is degreased by using anhydrous ethanol and dried in air.

[0058] (3) Laser cladding: The Q355 steel substrate after surface pretreatment is placed on the workbench of a laser cladding device, the composite powder is spread on the Q355 steel substrate, and the laser cladding device is operated to scan the spread composite powder on the Q355 steel substrate, while a protective gas is introduced to protect the atmosphere, so that the composite powder is completely melted and solidified to form a wear-resistant and corrosion-resistant composite coating on the Q355 steel substrate, which is completely metallurgically bonded, wherein the laser cladding process parameters are controlled as follows: laser power 1800W, spot diameter 4mm, scanning speed 10mm / s, and overlap rate 50%.

[0059] A wear-resistant and corrosion-resistant coating with a thickness of 1.0-1.5mm is prepared on the Q355 steel substrate by using Example 2, and the chemical composition of the coating is as follows in percentage by mass: C: 0.33wt%, V: 0.64wt%, B: 0.93wt%, Cr: 17.17wt%, Ni: 1.86wt%, Mo: 1wt%, Mn: 0.31wt%, and the balance of Fe.

[0060] After the workpiece with the prepared coating is cooled to room temperature, a sample is cut into a suitable size by wire cutting, and then inlaid, ground, polished and etched, and then a reciprocating friction experiment is carried out under the test conditions of a mechanical load of 80N, a wear rate of 6mm / s and a wear frequency of 1Hz, and an electrochemical test is carried out in a three-electrode system by using an electrochemical workstation, so as to test the wear resistance and corrosion resistance of the coating of Example 2, respectively, and the tests of the wear resistance and the corrosion resistance are both carried out in a simulated seawater solution containing 3.5wt% of chloride.

[0061] As Figure 3As shown, the coating of Example 2 exhibited diffraction peaks corresponding to body-centered cubic (BCC) structure of a-Fe and face-centered cubic (FCC) structure of γ-Fe, as well as M7C3, M3C and M 23 As shown, the coating of Example 2 exhibited diffraction peaks corresponding to body-centered cubic (BCC) structure of a-Fe and face-centered cubic (FCC) structure of γ-Fe, as well as M7C3, M3C and M Figure 4 As shown, the workpiece surface average hardness of Example 2 can reach 650HV 0.2 , which is more than 3 times higher than the hardness of the Q355 steel substrate itself. Figure 5 As shown, the coating after the friction and wear test, it can be clearly seen that the wear scar width and depth of the coating of Example 2 is smaller than that of Q355, and the wear resistance is improved. Figure 6 As shown, the coating of Example 2 exhibited diffraction peaks corresponding to body-centered cubic (BCC) structure of a-Fe and face-centered cubic (FCC) structure of γ-Fe, as well as M7C3, M3C and M Figure 7a As shown, the coating of Example 2 exhibited diffraction peaks corresponding to body-centered cubic (BCC) structure of a-Fe and face-centered cubic (FCC) structure of γ-Fe, as well as M7C3, M3C and M Figure 7b As shown, the coating of Example 2 exhibited diffraction peaks corresponding to body-centered cubic (BCC) structure of a-Fe and face-centered cubic (FCC) structure of γ-Fe, as well as M7C3, M3C and M Figure 7a As shown, the coating of Example 2 exhibited diffraction peaks corresponding to body-centered cubic (BCC) structure of a-Fe and face-centered cubic (FCC) structure of γ-Fe, as well as M7C3, M3C and M Figure 7b As shown, the coating of Example 2 exhibited diffraction peaks corresponding to body-centered cubic (BCC) structure of a-Fe and face-centered cubic (FCC) structure of γ-Fe, as well as M7C3, M3C and M Figure 6 As shown, the coating of Example 2 exhibited diffraction peaks corresponding to body-centered cubic (BCC) structure of a-Fe and face-centered cubic (FCC) structure of γ-Fe, as well as M7C3, M3C and M Figure 7a 、 7b According to the electrochemical test results of 1, 2, 3, 4, 5, 6, 7a, 7b, the corrosion resistance of the coating of Example 2 is significantly better than that of Q355. Figure 3 、 4 In 1, 2, 3, 4, 5, 6, 7a, 7b, the coating of Example 2 is denoted as "13-1".

[0062] It should be noted that the nomenclature and terminology herein have the meanings commonly understood by those skilled in the art unless otherwise specified. Moreover, when a numerical range is disclosed herein, the range is considered continuous along the entire range and includes each minimum and maximum value, as well as every value between the minimum and maximum values. Further, when multiple ranges are provided to describe a characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood as including any and all sub-ranges subsumed therein.

[0063] It should also be noted that the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that an item or apparatus including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such item or apparatus.

[0064] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can still be modified, or some technical features therein can be replaced by equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the present application.

Claims

1. A method for preparing a wear and corrosion resistant iron-based coating for marine environments, characterized in that, The method comprises the following steps: The composite powder is prepared by mixing and drying wear-resistant powder and corrosion-resistant powder in a proportion, wherein the wear-resistant powder has a chemical composition controlled as follows in percentage by mass: C: 1.9-2.2 wt%, V: 8-10 wt%, Cr: 4.5-5.2 wt%, Mo: 0.8-1.2 wt%, Mn: 0.4-0.6 wt%, and the balance of Fe; and the corrosion-resistant powder has a chemical composition controlled as follows in percentage by mass: C: 0.2-0.3 wt%, B: 0.8-1.2 wt%, Cr: 17-19 wt%, Ni: 1.5-2 wt%, Mo: 0.8-1.1 wt%, Mn: 0.2-0.5 wt%, and the balance of Fe. The laser cladding process parameters are controlled as follows: laser power: 1500-2000 W, spot diameter: 3-4 mm, scanning speed: 10-15 mm / s, and overlap rate: 45-55%.

2. The method of claim 1, wherein the iron-based wear and corrosion resistant coating for marine environments is prepared by, The proportion of the wear-resistant powder to the corrosion-resistant powder is controlled as follows: wear-resistant powder: corrosion-resistant powder = 1: (9-13).

3. The method of claim 1, wherein the iron-based wear and corrosion resistant coating for marine environments is prepared by, The particle size of the wear-resistant powder is controlled as 80-100 μm.

4. The method of claim 1, wherein the iron-based wear and corrosion resistant coating for marine environments is prepared by, The chemical composition of the wear-resistant powder is controlled as follows in percentage by mass: C: 2 wt%, V: 9 wt%, Cr: 5 wt%, Mo: 1 wt%, Mn: 0.5 wt%, and the balance of Fe; and the chemical composition of the corrosion-resistant powder is controlled as follows in percentage by mass: C: 0.2 wt%, B: 1 wt%, Cr: 18 wt%, Ni: 2 wt%, Mo: 1 wt%, Mn: 0.3 wt%, and the balance of Fe.

5. The method of claim 1, wherein the iron-based wear and corrosion resistant coating for marine environments is prepared by, The substrate surface pretreatment step is further included before the laser cladding step, wherein the substrate surface is first treated by a grinding wheel, and then polished flat by using sandpaper with mesh numbers of 400, 800 and 1200 in sequence to remove oil stains and oxides and increase roughness, and then degreased by using anhydrous ethanol and dried in air.

6. The method of claim 5, wherein the iron-based wear and corrosion resistant coating for marine environments is prepared by, The laser cladding step is specifically implemented as follows: the substrate after surface pretreatment is placed on a workbench of a laser cladding device, the composite powder is spread on the substrate, and the laser cladding device is operated to scan the spread composite powder on the substrate while protective gas is introduced for atmosphere protection.

7. The method of claim 1, wherein the iron-based wear and corrosion resistant coating for marine environments is prepared by, In the laser cladding step, the laser power is controlled as 1800 W, the spot diameter is controlled as 4 mm, the scanning speed is controlled as 10 mm / s, and the overlap rate is controlled as 50%.

8. The method of claim 1, wherein the iron-based wear and corrosion resistant coating for marine environments is prepared by, The prepared wear-resistant and corrosion-resistant coating has a thickness of 0.8-1.5 mm.

9. The method of producing a wear and corrosion resistant iron-based coating for marine environments according to any one of claims 1 to 8, characterized in that, The substrate is a Q355 steel substrate.

10. A marine environment iron-based wear-resistant and corrosion-resistant coating prepared by the marine environment iron-based wear-resistant and corrosion-resistant coating preparation method according to any one of claims 1 to 9, and the chemical composition of the marine environment iron-based wear-resistant and corrosion-resistant coating is C: 0.33-0.38 wt%, V: 0.64-0.9 wt%, B: 0.9-0.93 wt%, Cr: 16.7-17.17 wt%, Ni: 1.8-1.86 wt%, Mo: 0.8-1.1 wt%, Mn: 0.31-0.32 wt%, and the balance is Fe.

11. The iron-based wear and corrosion resistant coating for marine environments as claimed in claim 10, wherein, The surface hardness of the iron-based wear-resistant and corrosion-resistant coating for marine environment is ≥670 HV 0.2 .

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