Method for processing a substrate surface by laser cladding of stainless steel powder, material obtained therefrom and applications

Abstract

The application provides a processing method for heat treatment of a substrate surface laser cladding stainless steel powder, a material prepared by the method and an application, and belongs to the technical field of surface modification of metal materials. The processing method of the application modifies the cladding layer of 300M steel and AISI 420 stainless steel, so that the strong and tough substrate provides stable mechanical support for the cladding layer, and plastic deformation or cracking of the substrate due to thermal cycling during the cladding process is avoided. The heat treatment can regulate the carbon activity and phase composition of the substrate surface layer, inhibit the carbon migration phenomenon easily occurring at the interface between the cladding layer and the substrate, prevent the formation of a brittle carbide layer, and significantly improve the metallurgical bonding strength. At the same time, through the improvement of the laser cladding parameters and the adaptive heat treatment and post-treatment, the technology not only prolongs the service life of the substrate, but also strengthens the corrosion resistance and wear resistance of the surface.

Description

Technical Field

[0001] This invention relates to the field of surface modification technology for metallic materials, and more particularly to a processing method for laser cladding stainless steel powder on the surface of a heat-treated substrate, the materials prepared therefrom, and their applications. Background Technology

[0002] Laser cladding technology, as an advanced surface engineering technology, adds and melts high-performance alloy powder on the surface of a substrate to form a coating that is metallurgically bonded to the substrate. This creates a composite structure of "low-cost, high-toughness substrate + high-performance surface," which is expected to significantly improve the surface performance of key components without substantially increasing cost and weight.

[0003] However, applying laser cladding technology directly to large, thick workpieces of ultra-high strength steel such as 300M in existing technologies faces several severe technical challenges. On the one hand, the formed cladding layer is prone to cracking. During the rapid heating and cooling process of laser cladding, huge thermal stresses are generated. This stress can easily lead to cracks in the cladding layer, or even cause the coating to peel off from the substrate, resulting in the loss of the strengthening effect. On the other hand, the weakening of the bonding strength caused by interfacial carbon migration occurs. Under the high-temperature heat source of laser cladding, carbon elements in the substrate spontaneously migrate to the cladding layer region with higher chromium content, forming chromium-rich brittle carbides at the interface. This brittle phase not only severely weakens the metallurgical bonding strength between the coating and the substrate, becoming the source of crack propagation, but also consumes chromium elements in the cladding layer, leading to a decrease in chromium content near the interface and a decrease in corrosion resistance. Finally, the unstable corrosion resistance caused by defects in the cladding layer itself is another issue. Laser cladding is a rapid melting and solidification process, and stainless steel cladding layers are prone to forming coarse dendritic structures accompanied by elemental segregation. At the same time, there is usually a high residual tensile stress within the cladding layer. These microstructural defects and stress concentration points become the preferred sites for pitting corrosion initiation, causing the coating's corrosion resistance in actual corrosive environments to be far lower than the theoretical value, resulting in unstable and unreliable performance.

[0004] Therefore, finding an innovative and systematic processing method to fundamentally and collaboratively solve the above problems and prepare a crack-free coating with high bonding strength and stable corrosion and wear resistance remains a technical challenge that needs to be addressed by those skilled in the art.

[0005] Therefore, this invention is proposed. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a processing method for laser cladding stainless steel powder onto a heat-treated substrate, the materials obtained therefrom, and their applications. Through composite processing design, and the synergistic effect of substrate strengthening, interface optimization, and cladding layer functionalization, this invention provides an engineering solution for large, heavy-duty components. This technology not only extends the service life of the substrate but also enhances its corrosion and wear resistance through surface strengthening.

[0007] In order to achieve the objective of this invention, the following technical solution is adopted:

[0008] This invention provides a method for processing stainless steel powder by laser cladding on the surface of a heat-treated substrate, comprising the following steps:

[0009] S1. Pre-treat 300M steel and AISI 420 stainless steel powder respectively to obtain modified 300M steel and modified AISI 420 stainless steel powder respectively.

[0010] S2. Preheat the modified 300M steel, and then laser clad the surface with modified AISI 420 stainless steel powder;

[0011] S3. After the cladding is completed, heat, keep warm and cool to obtain the final product.

[0012] Furthermore, the preheating temperature in step S2 is 200℃-250℃.

[0013] Furthermore, the preprocessing includes the following steps:

[0014] S101. The 300M steel is subjected to one quenching and two tempering processes to obtain the matrix.

[0015] S102. The pure nickel powder is dried and preheated. Under an inert gas atmosphere, the pure nickel powder is uniformly sprayed onto the surface of the substrate while cooling it. The temperature during the spraying process is always below 200°C to obtain modified 300M steel.

[0016] S103. The AISI 420 stainless steel powder is mixed with nano-tungsten carbide-cobalt composite powder in a certain proportion, and ball-milled and dried under an inert gas atmosphere to obtain modified AISI 420 stainless steel powder.

[0017] Furthermore, the particle size of the pure nickel powder is 15μm-45μm, preferably 30μm.

[0018] Furthermore, the particle size of the nano-tungsten carbide-cobalt composite powder is 50nm-100nm, preferably 70nm.

[0019] Furthermore, in step S103, the ball milling speed is 200rpm-300rpm, and the ball milling time is 2h-4h.

[0020] Furthermore, in step S103, AISI 420 stainless steel powder and nano-tungsten carbide-cobalt composite powder are mixed at a mass ratio of 97:3.

[0021] Furthermore, the specific steps of the one quenching and two tempering processes are as follows:

[0022] Quenching was performed at 870℃, followed by holding at that temperature for 60 minutes and then cooling to room temperature.

[0023] Then temper at 300℃ for 120 minutes, and allow to cool naturally to room temperature;

[0024] It was then tempered a second time at 300℃ for 120 minutes and then naturally cooled to room temperature.

[0025] Furthermore, in the laser cladding process, the laser power is 2200W-2600W, the scanning speed is 8mm / s-12mm / s, the powder feeding rate is 25g / min-35mg / min, the working distance is 12mm-15mm, and the overlap rate is 40%-50%.

[0026] Furthermore, the laser power in the laser cladding is 2400W, the scanning speed is 9mm / s, the powder feeding rate is 30g / min, the working distance is 13.5mm, and the overlap rate is 50%.

[0027] Furthermore, step S3 specifically includes:

[0028] After the cladding is completed, all materials are placed at 300℃ for 2 hours and then cooled to room temperature.

[0029] Furthermore, in step S102, the preheating temperature is 200℃-250℃.

[0030] Furthermore, the composition of the untreated 300M steel is: C: 0.403wt%; Si: 1.03wt%; Cr: 5.41wt%; Mn: 0.41wt%; Ni: 0.06wt%; Mo: 1.24wt%; V: 0.096wt%; P: 0.017wt%; S: 0.002wt%; Fe is the balance.

[0031] The composition of untreated AISI420 stainless steel powder is as follows: C: 0.37wt%; Si: 0.76wt%; Cr: 12.89wt%; Mn: 0.64wt%; Ni: 0.51wt%; Mo: 0.31wt%; Nb: 0.048wt%; P: 0.005wt%; S: 0.009wt%; Fe is the balance.

[0032] The present invention also provides a single-pass or multi-pass AISI 420 stainless steel cladding layer material prepared by the above-mentioned processing method of laser cladding stainless steel powder on the surface of heat-treated substrate.

[0033] This invention also provides the application of the above-mentioned single-pass or multi-pass AISI 420 stainless steel cladding material in marine equipment or energy extraction.

[0034] The present invention has the following technical effects:

[0035] This invention provides a method for processing stainless steel powder by laser cladding on a heat-treated substrate, the materials obtained therefrom, and their applications. This method modifies the cladding layers of 300M steel and AISI 420 stainless steel, thereby providing a strong and tough substrate with stable mechanical support for the cladding layer, preventing plastic deformation or cracking of the substrate due to thermal cycling during the cladding process. Heat treatment can regulate the carbon activity and phase composition of the substrate surface, suppressing carbon migration at the interface between the cladding layer and the substrate, preventing the formation of brittle carbide layers, and thus significantly improving the metallurgical bonding strength.

[0036] Meanwhile, by improving the laser cladding parameters and adapting the heat treatment and post-treatment, this technology can not only extend the service life of the substrate, but also enhance its corrosion resistance and wear resistance through surface strengthening. Attached Figure Description

[0037] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 : This is a hardness curve obtained by testing with a Vickers hardness tester in Example 1;

[0039] Figure 2 : This is the open-circuit circuit diagram used in Experiment Example 1, tested with an electrochemical workstation;

[0040] Figure 3 : Tafel plot of Experiment Example 1 obtained using an electrochemical workstation;

[0041] Figure 4 : Impedance Nyquist plot obtained by electrochemical workstation in Experiment Example 1;

[0042] Figure 5 : Impedance Bode plot obtained by electrochemical workstation test in Experiment Example 1;

[0043] Figure 6 This is a graph showing the change in the coefficient of friction over time, as tested using a friction and wear testing machine in Experiment Example 2.

[0044] Figure 7 : This refers to the wear amount measured using a friction and wear testing machine in Experiment Example 3. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0046] In a first aspect, the present invention provides a method for processing stainless steel powder by laser cladding on the surface of a heat-treated substrate, comprising the following steps:

[0047] S1. Pre-treat 300M steel and AISI 420 stainless steel powder respectively to obtain modified 300M steel and modified AISI 420 stainless steel powder respectively.

[0048] S2. Preheat the modified 300M steel, and then laser clad the surface with modified AISI 420 stainless steel powder;

[0049] S3. After the cladding is completed, heat, keep warm, and cool to obtain the final product.

[0050] In some embodiments, the preprocessing includes the following steps:

[0051] S101. The 300M steel is subjected to one quenching and two tempering processes to obtain the matrix.

[0052] S102. The pure nickel powder is dried and preheated. Under an inert gas atmosphere, the pure nickel powder is uniformly sprayed onto the surface of the substrate while cooling it. The temperature during the spraying process is always below 200°C to obtain modified 300M steel.

[0053] S103. The AISI 420 stainless steel powder is mixed with nano-tungsten carbide-cobalt composite powder in a certain proportion, and ball-milled and dried under an inert gas atmosphere to obtain modified AISI 420 stainless steel powder.

[0054] In this invention, the heat treatment process of 300M steel can provide a toughened matrix, making it easier to form a cladding layer.

[0055] In step S102, a nickel layer is sprayed onto the treated 300M steel surface. This treatment method enables the nickel powder to form a dense, uniform nickel plating layer with a thickness of 80μm-120μm on the 300M steel surface. Part of the nickel plating layer can mechanically bond with the substrate, while another part undergoes metallurgical bonding with the substrate during the laser cladding process. Therefore, it exhibits a mixed state of mechanical and metallurgical bonding, ensuring that no interface defects occur even when using higher-performance composite powders.

[0056] Meanwhile, AISI 420 stainless steel underwent modification treatment by ball milling a mixture of AISI 420 stainless steel and nano-tungsten carbide-cobalt composite powder. The nano-tungsten carbide-cobalt composite powder provides extremely high hardness and wear resistance. This mixing process is not a simple one; a simple physical mixture would easily lead to segregation and cracking. The ball milling method under an inert atmosphere significantly enhances the wear resistance of AISI 420 stainless steel, effectively inhibits carbon migration, and prevents the reaction of carbon elements in the matrix with chromium elements in the cladding layer to form brittle carbides, greatly improving the interfacial bonding strength and corrosion resistance.

[0057] After laser cladding, the present invention further performs post-processing on the finished product in step S3. Specifically, the entire part undergoes low-temperature stress-relief annealing. This annealing temperature is lower than the recrystallization temperature of the cold-sprayed nickel layer, thus preventing recrystallization and softening of the cold-sprayed nickel layer and preserving its good toughness and strength. Specifically, the holding temperature is much lower than the tempering temperature of 300M steel, therefore it does not produce any annealing or softening effect on the already tempered substrate structure, strength, and hardness, perfectly preserving the strength and toughness of the substrate. At the same time, this temperature is highly consistent with the service temperature of 300M steel (the tempering temperature of 300M steel), which is sufficient to effectively eliminate residual stress generated during laser cladding and prevent stress corrosion cracking without negatively impacting the strength and hardness of the 300M steel substrate. Finally, the low-temperature heat treatment further promotes the diffusion of elements between the nickel layer and the substrate interface, enhancing the metallurgical bonding strength and making the entire coating system more stable and reliable.

[0058] In some embodiments, the preheating temperature in step S2 is 200°C-250°C.

[0059] In some embodiments, the particle size of the pure nickel powder is 15μm-45μm, preferably 30μm.

[0060] In some embodiments, the particle size of the nano-tungsten carbide-cobalt composite powder is 50nm-100nm, preferably 70nm.

[0061] The present invention also limits the particle size of pure nickel powder and nano-tungsten carbide-cobalt composite powder to prevent agglomeration caused by excessively large or small particle size.

[0062] In some embodiments, in step S103, the ball milling speed is 200rpm-300rpm and the ball milling time is 2h-4h.

[0063] The ball milling speed and time should not be too long to prevent a serious decrease in wear resistance due to excessive ball milling.

[0064] In some embodiments, in step S103, AISI 420 stainless steel powder and nano-tungsten carbide-cobalt composite powder are mixed at a mass ratio of 97:3.

[0065] This ratio represents the optimal blending ratio of AISI 420 stainless steel powder to nano-tungsten carbide-cobalt composite powder. Excessive addition of AISI 420 stainless steel powder does not significantly improve wear resistance; conversely, excessive addition of nano-tungsten carbide-cobalt composite powder can lead to nanoparticle agglomeration, increasing the risk of cladding layer cracking and reducing corrosion resistance. This ratio maximizes wear resistance while ensuring good cladding layer formation and corrosion resistance.

[0066] In some embodiments, the specific steps of the one quenching and two tempering are as follows:

[0067] Quenching was performed at 870℃, followed by holding at that temperature for 60 minutes and then cooling to room temperature.

[0068] Then temper at 300℃ for 120 minutes, and allow to cool naturally to room temperature;

[0069] It was then tempered a second time at 300℃ for 120 minutes and then naturally cooled to room temperature.

[0070] Pretreatment of 300M steel involves low-temperature processing of both nickel and the steel in step S102. During this process, quenching rapidly cools to form martensite, significantly improving the hardness and strength of the matrix. Subsequent tempering eliminates quenching stress and promotes the dispersed precipitation of carbides, maintaining strength while ensuring sufficient toughness and plasticity in the matrix. This strong and tough matrix provides stable mechanical support for the cladding layer, preventing plastic deformation or cracking due to thermal cycling during the cladding process. Heat treatment can regulate the carbon activity and phase composition of the matrix surface, suppressing carbon migration at the interface between the cladding layer and the matrix, preventing the formation of a brittle carbide layer, and thus significantly improving the metallurgical bonding strength.

[0071] In some embodiments, the laser power in the laser cladding is 2200W-2600W, the scanning speed is 8mm / s-12mm / s, the powder feeding rate is 25g / min-35mg / min, the working distance is 12mm-15mm, and the overlap rate is 40%-50%.

[0072] In some embodiments, the laser power in the laser cladding is 2400W, the scanning speed is 9mm / s, the powder feeding rate is 30g / min, the working distance is 13.5mm, and the overlap rate is 50%.

[0073] The parameters for this laser cladding are not general parameters, but are specifically optimized to suit the pretreated substrate and modified powder. This parameter range ensures that the nanoparticles are fully melted and evenly distributed, and that the nickel transition layer and the cladding layer achieve good metallurgical bonding without being overly diluted. At the same time, the heat input is moderate, which can both ensure the cladding quality and control stress and deformation.

[0074] In some embodiments, step S3 specifically includes:

[0075] After the cladding is completed, all materials are placed at 300℃ for 2 hours and then cooled to room temperature.

[0076] Step S3 is the post-processing step, where the selection of temperature and time is crucial. The temperature should be lower than the recrystallization temperature of the cold-sprayed nickel layer to prevent the nickel layer from becoming too soft and slippery; at the same time, it should be sufficient to eliminate most of the residual stress generated by laser cladding.

[0077] In some embodiments, the preheating temperature in step S102 is 200°C-250°C.

[0078] Moderate preheating of nickel powder can lower the critical deposition rate of cold-sprayed particles, making them easier to deposit and improving the deposition efficiency and density of the nickel layer. This helps to form a more complete and denser nickel barrier layer, thereby more effectively inhibiting carbon migration.

[0079] In some embodiments, the untreated 300M steel has the following composition: C: 0.403 wt%; Si: 1.03 wt%; Cr: 5.41 wt%; Mn: 0.41 wt%; Ni: 0.06 wt%; Mo: 1.24 wt%; V: 0.096 wt%; P: 0.017 wt%; S: 0.002 wt%; Fe is the balance.

[0080] In some embodiments, the composition of the untreated AISI 420 stainless steel powder is as follows: C: 0.37 wt%; Si: 0.76 wt%; Cr: 12.89 wt%; Mn: 0.64 wt%; Ni: 0.51 wt%; Mo: 0.31 wt%; Nb: 0.048 wt%; P: 0.005 wt%; S: 0.009 wt%; Fe is the balance.

[0081] Secondly, the present invention also provides a single-pass or multi-pass AISI 420 stainless steel cladding layer material prepared by the above-mentioned processing method of laser cladding stainless steel powder on the surface of heat-treated substrate.

[0082] Thirdly, the present invention also provides the application of single- or multi-pass AISI 420 stainless steel cladding materials in marine equipment or energy extraction.

[0083] The following is a detailed explanation using specific embodiments:

[0084] Example 1

[0085] (1) Place 300M steel into a high-temperature box furnace, heat it to 870℃, hold it for 60 minutes, and then cool it to room temperature.

[0086] (2) The quenched 300M steel obtained in step (1) is placed in a furnace for one tempering at a temperature of 300℃ and held for 120 minutes, and then cooled to room temperature in air.

[0087] (3) The 300M steel obtained in step (2) is placed in a furnace for secondary tempering at a temperature of 300℃ and held for 120 minutes. It is then cooled to room temperature in air to obtain the base 300M steel.

[0088] (4) Use sandpaper to polish the surface of the 300M steel obtained in step (3) after two tempering processes, rinse with anhydrous ethanol, blow dry, and put into a 100℃ drying oven for later use.

[0089] (5) Place AISI 420 stainless steel powder in a 100℃ drying oven and dry for 1 hour; place pure nickel powder in a 100℃ drying oven and dry for 2 hours to remove moisture, while preheating.

[0090] (6) Under nitrogen atmosphere, a nickel layer is sprayed on the surface of 300M steel. The spraying distance is set to 30mm and the spray gun moving speed is 15mm / s. During the spraying process, the temperature of the substrate is kept below 200℃. When the temperature approaches 200℃, attention is paid to cooling the substrate to obtain modified 300M steel.

[0091] (7) AISI 420 stainless steel powder and nano tungsten carbide-cobalt composite powder (WC / Co powder) are mixed in a mass ratio of 97:3. The mixed powder is placed in a high-energy ball mill and ball-milled at 200 rpm for 3 hours. Then it is dried in a drying oven at 100°C for 1 hour to obtain modified AISI 420 stainless steel powder.

[0092] (8) The modified 300M steel is placed in a heating furnace and preheated to 230℃ to prevent the modified 300M from cracking. Modified AISI 420 stainless steel powder is laser-clad on the surface of the modified 300M steel. The specific laser cladding process parameters are as follows: laser power is 2400W, scanning speed is 9mm / s, powder feeding rate is 30g / min, working distance is 13.5mm, cladding length is 60mm, and a single-pass AISI 420 stainless steel cladding layer material is obtained.

[0093] (9) The hardness distribution of a single-pass cladding layer was tested using a Vickers microhardness tester. During the hardness measurement, a load of 1 kg was applied and the holding time was 10 s. After polishing the sample cross-section, it was placed on the stage of the microhardness tester and measured perpendicular to the laser cladding cross-section area. Taking the bottom of the cladding layer as the reference plane, 10 points were measured vertically upwards and 24 points were measured vertically downwards. Three points were measured horizontally, and the vertical point interval was 0.1 mm.

[0094] Experimental results are as follows Figure 1 As shown in the figure, the hardness of the cladding layer is higher than that of the substrate. This is because the AISI 420 cladding layer contains a large amount of chromium. The maximum hardness of the cladding layer is located at the top of the cladding layer. This is because the top layer is composed of finer and denser equiaxed crystals. The refined dendrites enhance the surface hardness of the coating, giving it a denser microstructure.

[0095] Experiment Example 1: Corrosion Resistance Test

[0096] Take the cladding material prepared in Example 1.

[0097] (1) Cut the modified 300M steel and modified AISI 420 stainless steel cladding material into 10×10×5mm squares using a wire cutting machine, then use a welding gun to connect them to the wires and seal them in epoxy resin. After drying, grind off the epoxy resin on the surface of the material on 2000 grit sandpaper.

[0098] (2) Prepare a 3.5% NaCl solution as an electrochemical solution and use an electrochemical experimental platform for testing. The material is used as the working electrode, the saturated calomel electrode is used as the reference electrode, and the platinum sheet is used as the auxiliary electrode to build a three-electrode system.

[0099] (3) Electrochemical testing experiments were conducted on the materials, including open circuit potential (OPC) testing, electrochemical impedance spectroscopy (EIS) testing, and potentiodynamic testing. The open circuit potential testing time was 60 min, the electrochemical impedance spectroscopy frequency range was 100 kHz to 10 mHz, the amplitude was 10 mV, and the recommended initial voltage for potentiodynamic testing / Tafel was [missing value]. 0.3V, stop voltage 0.3V, scan rate 0.001V / s. Experimental results are as follows: Figure 2-5 As shown.

[0100] pass Figure 2 The data shows that the open circuit potential of the cladding layer is higher than that of the 300M steel substrate, indicating that the cladding layer has better corrosion resistance.

[0101] pass Figure 3 After Tafel fitting and analysis of the polarization curves, the self-corrosion potential and corrosion current were obtained. The corrosion current density of the cladding layer was lower than that of the substrate, indicating that the cladding layer had better corrosion resistance.

[0102] pass Figure 4 The Nyquist plot of the medium impedance shows that the radius of the capacitive arc of the cladding layer is much larger than that of the substrate, indicating that the cladding layer has better corrosion resistance.

[0103] pass Figure 5 The Bode plot of the impedance shows that the phase angle is close to 0 in the 4-5 high-frequency region, indicating that the impedance in this region is mainly solution impedance. In the mid-frequency range of 0-4, the phase angle reaches its maximum value, with the cladding material being higher than the substrate, exhibiting typical capacitive characteristics. This indicates that the passivation film on the material surface tends to be a capacitive insulating layer, and the passivation film has a certain protective effect on the material. In the low-frequency region of -2-0, the impedance (Z) represents the impedance of the corrosion reaction. In the low-frequency region, the impedance of the cladding layer is greater than that of the substrate, indicating that it is more difficult for corrosive ions in 3.5% NaCl solution to corrode through the passivation film on the surface of the cladding layer, and the cladding layer is more corrosion resistant.

[0104] Experimental Example 2: Abrasion Resistance Test of Cladding Materials

[0105] Take the cladding material prepared in Example 1.

[0106] (1) Modified 300M steel and modified AISI 420 stainless steel cladding material were processed into pins with a diameter of 4 mm and a height of 12 mm. Friction and wear tests were conducted using a friction and wear testing machine. Based on the experimental data, the friction coefficient versus time curve was plotted, and the average friction coefficient of both materials was calculated. The experimental results are as follows: Figure 6 As shown.

[0107] The average friction coefficient of the AISI 420 cladding layer is 0.552, which is significantly lower than the average friction coefficient of 0.830 for 300M steel, a reduction of 35.1%. This indicates that laser cladding of AISI 420 stainless steel powder onto the surface of tempered 300M steel significantly reduces the surface friction coefficient and improves its wear resistance.

[0108] Experimental Example 3

[0109] Take the cladding material prepared in Example 1.

[0110] (1) Tempered 300M steel and AISI 420 stainless steel cladding material were processed into material pins with a diameter of 4mm and a height of 12mm. Before the friction and wear test, all material pins were weighed separately. The friction and wear test was carried out using a friction and wear testing machine. All material pins that had undergone the friction and wear test were weighed again, and their wear amount was calculated. The experimental results are as follows: Figure 7 As shown.

[0111] The wear amount of the 300M steel pin was 0.54mg, while that of the AISI 420 cladding material pin was 0.24mg. Data shows that the AISI 420 cladding material pin exhibited less wear over the same time period, demonstrating superior wear resistance compared to the 300M steel pin.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A method for processing a laser cladding of stainless steel powder on a surface of a substrate by heat treatment, characterized in that, It comprises the following steps: S1, respectively, pretreat 300M steel and AISI 420 stainless steel powder, and obtain modified 300M steel and modified AISI 420 stainless steel powder respectively; S2, preheat the modified 300M steel, and then surface laser cladding modified AISI 420 stainless steel powder; S3, after cladding, heat, keep warm and cool, and obtain; The specific steps of S1 are: S101, quench the 300M steel once and temper it twice to obtain a substrate; S102, dry and preheat pure nickel powder, cool the substrate while spraying the pure nickel powder uniformly on the surface of the substrate in the atmosphere of inert gas, and the temperature during the spraying process of S102 is always lower than 200 DEG C, to obtain modified 300M steel; S103, mix the AISI 420 stainless steel powder with nano tungsten carbide-cobalt composite powder in proportion, and ball mill in the atmosphere of inert gas, and dry to obtain modified AISI 420 stainless steel powder; The laser cladding has a laser power of 2200 W-2600 W, a scanning speed of 8 mm / s-12 mm / s, a powder feeding rate of 25 g / min-35 mg / min, a working distance of 12 mm-15 mm, and an overlapping rate of 40%-50%; The specific steps of S3 are: After cladding, place all the materials at 300 DEG C for 2 h, and then cool to room temperature; In the step S103, the AISI 420 stainless steel powder and the nano tungsten carbide-cobalt composite powder are mixed in a mass ratio of 97:

3.

2. The method of claim 1, wherein the laser cladding of the stainless steel powder on the substrate surface is performed by a heat treatment. The specific steps of the once quenching and twice tempering are: ​ Quench at 870 DEG C, and then keep warm for 60 min and cool to room temperature; Then temper at 300 DEG C, keep warm for 120 min, and naturally cool to room temperature; Then secondly temper at 300 DEG C, keep warm for 120 min, and naturally cool to room temperature.

3. The processing method for laser cladding stainless steel powder on the surface of a heat-treated substrate according to claim 1, characterized in that, In the step S102, the preheating temperature is 200 DEG C-250 DEG C.

4. A single or multi-track AISI 420 stainless steel cladding layer material prepared by the processing method of claim 1-3.

5. The single or multi-track AISI 420 stainless steel cladding layer material of claim 4 is applied in marine equipment or energy exploitation.

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