Metal powder, Fe3Al composite coating and preparation method thereof

Abstract

The invention belongs to the technical field of metal coatings, and particularly relates to metal powder, a Fe3Al composite coating and a preparation method of the Fe3Al composite coating. The invention provides metal powder. The metal powder comprises the following components: 9.8-12.9% of Al; 0.09% to 0.2% of B; 17 to 34 percent of Cr; 2 to 4.6 percent of C; 0.5 to 2 percent of Ni; 0.15% to 0.22% of Zr; 0.5 to 1.5 percent of Mg; the steel comprises the following components in percentage by mass: 0.2-0.6% of Si, and the balance of Fe and inevitable impurities. According to the metal powder provided by the invention, all the elements are matched with one another, and the content of all the elements is optimized, so that when the metal powder is used for preparing the composite coating, the obtained composite coating has good plasticity, and no crack is formed.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal coatings, and in particular relates to a metal powder, an Fe3Al composite coating and a preparation method thereof. Background Art

[0002] Laser cladding technology is an advanced surface treatment technology. With the continuous improvement of laser power and the increase of stability, laser cladding technology has been fully developed and promoted. Laser cladding technology can obtain the designed alloy coating on the surface of the part. The coating and the substrate show good metallurgical bonding, achieving the required properties, such as hardness, thermal stability, wear resistance, etc. For laser cladding, the alloy composition design of the alloy coating is particularly important. At present, the laser cladding alloys mainly include nickel-based alloys, cobalt-based alloys and iron-based alloys. Since most of the parts used in actual production are iron-carbon alloys, compared with nickel-based alloys and cobalt-based alloys, iron-based alloys are closer to the composition of the parts, have a stronger bond with the substrate, and have a low preparation cost and are easy to promote and use. Therefore, it is of great significance to study iron-based alloy powders.

[0003] At present, the modification of iron-based alloy powder mainly focuses on two aspects. On the one hand, the composition of iron-based alloy powder is improved. For example, adding element B to the powder can significantly improve the plasticity of the composite material. On the other hand, the microstructure of Fe3Al alloy is improved and its strength and toughness are increased by optimizing the heat treatment process, such as tempering and annealing. Summary of the Invention

[0004] The present invention is based on the inventors' discovery and understanding of the following facts and problems: In related art, improvements to the composition of iron-based alloy powders were made using elements introduced into the iron-based alloy powder matrix through experimental experience, and their types and contents did not achieve optimal results. Improper additions may cause the formation of new phases, which in turn affect the strength and toughness of the alloy. Furthermore, whether there are other previously unstudied elements that can significantly enhance its strength and toughness requires further study. Adding a heat treatment process not only makes the overall preparation process more cumbersome, but also makes its control very complex. If the heat treatment temperature or time is not precisely controlled, a brittle phase may appear, affecting the coating's performance.

[0005] The present invention aims to address, at least to some extent, one of the technical problems in the related art. To this end, embodiments of the present invention provide a metal powder in which the elements are coordinated with each other and the content of each element is optimized so that, when used to prepare a composite coating, the resulting composite coating has good plasticity and wear resistance and is free of crack formation.

[0006] The metal powder of the embodiment of the present invention includes the following components: Al: 9.8-12.9%; B: 0.09-0.2%; Cr: 17-34%; C: 2-4.6%; Ni: 0.5-2%; Zr: 0.15-0.22%; Mg: 0.5-1.5%; Si: 0.2-0.6%, and the remainder is Fe and unavoidable impurities, calculated in percentage by mass.

[0007] The advantages and technical effects brought by the metal powder of the embodiment of the present invention are as follows: 1. In the embodiment of the present invention, the formula of the metal powder is obtained based on the first-principles calculation of density functional theory. Compared with the traditional empirical formula for given alloying elements, it can significantly shorten the time for experimental verification and improve the performance of metal powder alloy materials; 2. In the metal powder of the embodiment of the present invention, Al and Fe are basic constituent elements, B is used to strengthen the intercrystalline bonding force, Ni, Mg, and Cr are solid-solution elements of Fe3Al, and through solid-solution substitution, Fe3Al is converted into plastic phases such as Fe2AlCr and Fe2AlNi, thereby improving the plasticity of Fe3Al, Cr and C are used to form Cr7C3 strengthening phases to enhance the wear resistance of the material, Zr is used to refine the grains, and Mn and Si are used to improve hardness and deoxidation; 3. In the embodiment of the present invention, the composite coating prepared using the metal powder has good plasticity and wear resistance, and no cracks are formed.

[0008] In some embodiments, the metal powder includes the following components: Al: 11.4%; B: 0.09%; Cr: 26.5%; C: 3.3%; Ni: 1.25%; Zr: 0.22%; Mg: 0.80%; Si: 0.40%, and the remainder is Fe and unavoidable impurities, calculated in percentage by mass.

[0009] In some embodiments, the metal powder has a particle size of 80 to 125 μm.

[0010] An embodiment of the present invention further provides a method for preparing a Fe3Al composite coating, comprising the following steps: pre-treating the substrate surface, laser cladding the substrate surface using the above-mentioned metal powder as laser cladding powder, and obtaining the Fe3Al composite coating after cooling.

[0011] The advantages and technical effects brought by the preparation method of the embodiment of the present invention are as follows: 1. The Fe3Al composite coating prepared by the method of the embodiment of the present invention has good plasticity and no cracks, and has very good wear resistance; 2. The method of the embodiment of the present invention has a simple process, is easy to operate, and is convenient for promotion and application in industrial production.

[0012] In some embodiments, the pretreatment includes polishing the substrate surface with sandpaper and then cleaning with acetone.

[0013] In some embodiments, the wavelength used in the laser cladding is 1.064 μm or 1.07 μm;

[0014] And / or, the powder feeding method of the laser cladding is coaxial powder feeding;

[0015] and / or, and / or, the scanning speed of the laser cladding is 0.002-0.005 m / s, the powder feeding speed is 2-5 kg / h, and the laser power is 8000-15000 W;

[0016] And / or, the laser cladding spot is a rectangular spot of (2-4) mm×(22-25) mm.

[0017] In some embodiments, the shielding gas and powder carrier gas used in the laser cladding are high-purity argon gas, and the flow rate of the shielding gas is 10 to 25 L / min.

[0018] In some embodiments, the Fe3Al composite coating includes a first cladding coating, a second cladding coating, and a third cladding coating;

[0019] And / or, the thickness of the Fe3Al composite coating is 8-9 mm.

[0020] In some embodiments, the overlap rate of the first cladding coating is 20-25%, the overlap rate of the second cladding coating is 18-23%, and the overlap rate of the third cladding coating is 16-21%.

[0021] An embodiment of the present invention further provides a Fe3Al composite coating, which is prepared using the above-mentioned preparation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 are photos of the first cladding coating, the second cladding coating, and the third cladding coating prepared in Example 1;

[0023] Figure 2 is a photograph of the coating prepared in Comparative Example 1;

[0024] Figure 3 Surface morphologies of the Fe3Al composite coating prepared in Example 1 and the coating prepared in Comparative Example 1 after wear. DETAILED DESCRIPTION

[0025] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0026] The metal powder of the embodiment of the present invention includes the following components: Al: 9.8-12.9%; B: 0.09-0.2%; Cr: 17-34%; C: 2-4.6%; Ni: 0.5-2%; Zr: 0.15-0.22%; Mg: 0.5-1.5%; Si: 0.2-0.6%, and the remainder is Fe and unavoidable impurities, calculated in percentage by mass.

[0027] The formula of the metal powder in the embodiment of the present invention is obtained based on the first principles calculation of density functional theory. Compared with the traditional empirical formula for given alloying elements, it can significantly shorten the time for experimental verification and improve the performance of metal powder alloy materials. In the metal powder in the embodiment of the present invention, Al and Fe are basic components, B is used to strengthen the intercrystalline bonding force, Ni, Mg, and Cr are solid solution elements of Fe3Al, and through solid solution substitution, Fe3Al is converted into plastic phases such as Fe2AlCr and Fe2AlNi, thereby improving the plasticity of Fe3Al. Cr and C are used to form Cr7C3 strengthening phases to enhance the wear resistance of the material, Zr is used to refine the grains, and Mn and Si are used to improve the hardness and deoxidation. The composite coating prepared using the metal powder in the embodiment of the present invention has good plasticity and wear resistance, and no cracks are formed.

[0028] In some embodiments, preferably, the metal powder comprises the following components: Al: 11.4%; B: 0.09%; Cr: 26.5%; C: 3.3%; Ni: 1.25%; Zr: 0.22%; Mg: 0.80%; Si: 0.40%, and the remainder is Fe and unavoidable impurities, calculated in percentage by mass.

[0029] In some embodiments, preferably, the particle size of the metal powder is 80-125 μm, for example, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm, etc.

[0030] An embodiment of the present invention further provides a method for preparing a Fe3Al composite coating, comprising the following steps: pre-treating the substrate surface, laser cladding the substrate surface using the above-mentioned metal powder as laser cladding powder, and obtaining the Fe3Al composite coating after cooling.

[0031] The Fe3Al composite coating prepared by the preparation method of the embodiment of the present invention has good plasticity and no cracks, and has very good wear resistance; the method of the embodiment of the present invention has a simple process, is easy to operate, and is convenient for promotion and application in industrial production.

[0032] In some embodiments, the pretreatment preferably includes polishing the substrate surface with sandpaper and then cleaning with acetone. Polishing the substrate surface with sandpaper can reduce the brightness of the substrate surface and remove the surface oxide layer, which is beneficial for improving the bonding performance between the composite coating and the substrate surface.

[0033] In some embodiments, preferably, the substrate is made of any one of carbon steel, stainless steel, cast iron, and the like.

[0034] In some embodiments, preferably, the wavelength used in the laser cladding is 1.064 μm or 1.07 μm;

[0035] And / or, the powder feeding method of the laser cladding is coaxial powder feeding.

[0036] In some embodiments, preferably, the scanning speed of the laser cladding is 0.002 to 0.005 m / s, for example, 0.002 m / s, 0.003 m / s, 0.004 m / s or 0.005 m / s, etc.; the powder feeding speed is 2 to 5 kg / h, for example, 2 kg / h, 3 kg / h, 4 kg / h, 5 kg / h, etc.; the laser power is 8000 to 15000 W, for example, 8000, 9000, 10000 W, 11000 W, 12000 W, 13000 W, 14000 W, 15000 W, etc.

[0037] In the embodiment of the present invention, the parameters of laser cladding are optimized. By using a smaller scanning speed and a larger laser power, the heat input per unit length is increased. On the one hand, the metal powder and the matrix parent material are more fully fused, fully ensuring the metallurgical bonding and bonding strength; on the other hand, when multiple layers are stacked, the larger heat input can improve the stress state to a certain extent.

[0038] In some embodiments, preferably, the laser cladding spot is a rectangular spot of (2-4) mm x (22-25) mm. Further preferably, the laser cladding spot is a rectangular spot of 3 mm x 24 mm.

[0039] In some embodiments, preferably, the shielding gas and powder carrier gas used in the laser cladding are high-purity argon, and the flow rate of the shielding gas is 10 to 25 L / min, for example, 10 L / min, 11 L / min, 12 L / min, 13 L / min, 14 L / min, 15 L / min, 16 L / min, 17 L / min, 18 L / min, 19 L / min, 20 L / min, 21 L / min, 22 L / min, 23 L / min, 24 L / min, 25 L / min, etc.

[0040] In some embodiments, preferably, the Fe3Al composite coating includes a first cladding coating, a second cladding coating, and a third cladding coating. The first cladding coating is metallurgically bonded to the substrate surface, the second cladding coating is metallurgically bonded to a side of the first cladding coating away from the substrate surface, and the third cladding coating is metallurgically bonded to a side of the second cladding coating away from the substrate surface.

[0041] In the embodiment of the present invention, the Fe3Al composite coating preferably includes three layers of cladding coating. The three-layer design can realize the preparation of a high-thickness cladding layer, thereby extending the service life. It is difficult to prepare such a high thickness with a single layer, but layering can be achieved relatively easily.

[0042] In some embodiments, preferably, the Fe3Al composite coating has a thickness of 8 to 9 mm, wherein the thickness of the first cladding coating is 2.5 to 3 mm, the thickness of the second cladding coating is 2.5 to 3 mm, and the thickness of the third cladding coating is 2.5 to 3 mm.

[0043] In some embodiments, preferably, the overlap rate of the first cladding coating is 20-25%, the overlap rate of the second cladding coating is 18-23%, and the overlap rate of the third cladding coating is 16-21%.

[0044] The technical solution of the present invention is described in detail below with reference to specific embodiments and drawings.

[0045] Example 1

[0046] (1) Polish the surface of the 45# steel substrate with 320# SiC sandpaper to reduce its brightness and remove the surface oxide layer, and then clean and wipe the polished substrate with acetone;

[0047] (2) preparing a metal powder according to the following proportions: Al: 12.9%; B: 0.09%; Cr: 18%; C: 2%; Ni: 1.25%; Zr: 0.22%; Mg: 0.8%; Si: 0.4%, with the remainder being Fe and unavoidable impurities, calculated in percentage by mass; and having a particle size of 95 to 100 μm;

[0048] (3) A Gaussian distribution focusing lens was selected for the laser head to generate a rectangular laser spot with a size of 3 mm × 24 mm. The powder feeding method was coaxial powder feeding. The shielding gas and powder carrier gas used in the laser cladding process were both high-purity argon (99.99%), and the shielding gas flow rate was 15 L / min.

[0049] (4) The laser wavelength was set to 1.07 μm, the laser scanning speed was 0.002 m / s, the powder feeding speed was 3 kg / h, and the laser power was 10,000 W for laser cladding. Three layers of cladding coatings were formed on the surface of the substrate. The overlap rate of the first cladding coating was 20%, and the thickness was 2.6 to 3 mm. The overlap rate of the second cladding coating was 18%, and the thickness was 2.6 to 3 mm. The overlap rate of the third cladding coating was 16%, and the thickness was 2.6 to 3 mm. The thickness of the composite coating was 8 to 9 mm.

[0050] Wherein, the first cladding coating formed on the substrate surface is as follows Figure 1 As shown in a, the second cladding coating formed on the first cladding coating is as shown in Figure 1 As shown in b, the third cladding coating formed on the second cladding coating is as shown in Figure 1 As shown in c. Figure 1 It can be seen from the figure that the composite coating is made by successively cladding three layers of the metal powder in this embodiment, and no cracks appear in any of the layers, indicating that the composite coating has good plasticity.

[0051] The wear rate of the Fe3Al composite coating prepared in this embodiment is 0.325×10 -5 mm 3 / N*m.

[0052] Example 2

[0053] The preparation method of this embodiment is the same as that of Example 1, except that, in step (2), the composition of the metal powder is: Al: 11.4%; B: 0.09%; Cr: 26.5%; C: 3.3%; Ni: 1.25%; Zr: 0.22%; Mg: 0.8%; Si: 0.4%, and the remainder is Fe and unavoidable impurities, calculated in percentage by mass.

[0054] The wear rate of the Fe3Al composite coating prepared in this embodiment is 0.285×10 -5 mm 3 / N*m.

[0055] Example 3

[0056] The preparation method of this embodiment is the same as that of Example 1, except that in step (2), the composition of the metal powder is: Al: 9.81%; B: 0.09%; Cr: 34%; C: 4.6%; Ni: 1.25%; Zr: 0.22%; Mg: 0.8%; Si: 0.4%, and the remainder is Fe and unavoidable impurities, calculated in percentage by mass.

[0057] The wear rate of the composite coating prepared in this embodiment is 0.396×10 -5 mm 3 / N*m.

[0058] Comparative Example 1

[0059] The preparation method of this comparative example is the same as that of Example 1, except that pure Fe3Al alloy is used to prepare the coating.

[0060] The photo of the coating prepared in this comparative example is shown in FIG. Figure 2 As shown, from Figure 2 It can be seen that the coating obtained in this comparative example has obvious cracks.

[0061] The wear rate of the coating prepared in this comparative example is 0.514×10 -5 mm 3 / N*m.

[0062] In addition, the surface morphology of the Fe3Al composite coating in Example 1 and the coating in Comparative Example 1 after wear was characterized, and the results were as follows: Figure 3 As shown, from Figure 3 It can be seen from the figure that the coating material made from the metal powder in the embodiment of the present invention has relatively slight wear and better wear resistance.

[0063] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0064] Although the above embodiments have been shown and described, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are all within the scope of protection of the present invention.

Claims

1. A metal powder, characterized in that: It includes the following components: Al: 9.8-12.9%; B: 0.09~0.2%; Cr: 17~34%; C: 2~4.6%; Ni: 0.5-2%; Zr：0.15～0.22％； Mg: 0.5-1.5%; Si: 0.2-0.6%, the balance being Fe and unavoidable impurities, calculated as percentage by mass.

2. The metal powder according to claim 1, characterized in that It includes the following components: Al: 11.4%; B: 0.09%; Cr: 26.5%; C: 3.3%; Ni: 1.25%; Zr: 0.22%; Mg: 0.80%; Si: 0.40%, the balance being Fe and inevitable impurities, calculated in percentage by mass.

3. The metal powder according to claim 1 or 2, characterized in that The particle size of the metal powder is 80 to 125 μm.

4. A method for preparing a Fe3Al composite coating, characterized in that: The following steps are involved: After pre-treating the substrate surface, the metal powder according to any one of claims 1 to 3 is used as laser cladding powder to perform laser cladding on the substrate surface, and Fe3Al composite coating is obtained after cooling.

5. The method for preparing the Fe3Al composite coating according to claim 4, characterized in that: The pretreatment includes polishing the substrate surface with sandpaper and then cleaning it with acetone.

6. The method for preparing the Fe3Al composite coating according to claim 4, characterized in that: The wavelength used in the laser cladding is 1.064 μm or 1.07 μm; And / or, the powder feeding method of the laser cladding is coaxial powder feeding; And / or, the scanning speed of the laser cladding is 0.002-0.005 m / s, the powder feeding speed is 2-5 kg / h, and the laser power is 8000-15000 W; And / or, the laser cladding spot is a rectangular spot of (2-4) mm×(22-25) mm.

7. The method for preparing the Fe3Al composite coating according to claim 4, characterized in that: The protective gas and / or powder carrier gas used in the laser cladding is high-purity argon gas, and the flow rate of the protective gas is 10 to 25 L / min.

8. The method for preparing the Fe3Al composite coating according to claim 4, characterized in that: The Fe3Al composite coating includes a first cladding coating, a second cladding coating and a third cladding coating; And / or, the thickness of the Fe3Al composite coating is 8-9 mm.

9. The method for preparing the Fe3Al composite coating according to claim 8, characterized in that: The overlap rate of the first cladding coating is 20-25%, the overlap rate of the second cladding coating is 18-23%, and the overlap rate of the third cladding coating is 16-21%.

10. A Fe3Al composite coating, characterized in that: The preparation method is described in any one of claims 4 to 9.

Images