High-nitrogen low-nickel alloy powder for 3D printing and preparation method thereof

Abstract

The invention relates to the technical field of alloy powder, in particular to high-nitrogen low-nickel alloy powder for 3D printing and a preparation method thereof, and is characterized in that the alloy powder comprises the following chemical components in percentage by weight: 45.0 wt% of Ni, 25 wt% of Cr, 7.0 wt% of Mn, 1.6 wt% of Si, 6 wt% of Mo, 0.24 wt% of Cu, 0.81 wt% of Co, 0.60 wt% of N, 1.4 wt% of Al, 1.43 wt% of Ti, 6 wt% of Nb, 2.6 wt% of W, 1.3 wt% of V and the balance of Fe and inevitable impurities. Compared with the prior art, the high-nitrogen low-nickel alloy powder for 3D printing has the beneficial effects that the high-nitrogen low-nickel alloy powder for 3D printing is prepared by reasonably designing the chemical components and the preparation method of the alloy powder, and the high-nitrogen low-nickel alloy powder is high in sphericity degree, good in compactness and low in oxygen content; and the high-temperature oxidation resistance of the alloy is improved while the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy powders, and in particular to a high-nitrogen and low-nickel alloy powder for 3D printing and a preparation method thereof. Background Art

[0002] Nickel-based alloy powders, as key materials for repairing high-temperature components, have good fracture toughness and corrosion resistance, and also have good spraying and cladding effects, and can be widely used in the aerospace field. Laser additive manufacturing technology is a process method without the need for molds, with free and flexible design methods, effectively reducing energy and time consumption, high part precision, and good performance of formed structural parts. Therefore, laser additive manufacturing technology has received wide attention and has gradually become an effective way to solve complex structural parts in aircraft manufacturing. It can even achieve the one-piece forming of dozens or even hundreds of traditional parts, and can accurately design and complete the precise forming of parts with high complexity, and is widely used in many fields. In addition, the additive manufacturing technology has the characteristics of rapid cooling, which makes the aluminum alloy formed under this process have more excellent performance than the traditional process. At present, nickel-based alloys have been able to achieve 3D printing, but their mechanical properties are poor and they cannot play the role of stressed parts. When traditional nickel-based alloys are used for additive manufacturing, thermal cracks are easily generated, which severely limits their application and development, and the related forming technology lags far behind other alloy materials.

[0003] Like nickel, nitrogen is also an element that can form austenite and expand the phase region, and the ability of nitrogen is much greater than that of nickel. In duplex stainless steel, the ability of nitrogen to stabilize austenite at high temperatures is also greater than that of nickel. Because the austenite-forming ability of nitrogen is 18 times that of nickel. In addition, nitrogen elements can improve the high-temperature corrosion resistance of steel, and the combination of N elements with W and Cr elements will improve the high-temperature mechanical properties of materials.

[0004] Chinese Patent No. 201811553628.9 discloses a high-nitrogen and low-nickel austenitic stainless steel alloy and a manufacturing method thereof. Adding vanadium elements to the high-nitrogen and low-nickel stainless steel alloy can increase the nitrogen solubility, reduce the nickel consumption, and reduce the manufacturing cost, providing a new idea for the preparation of high-nitrogen steel. Although adding vanadium elements can increase the solubility of nitrogen elements in this manufacturing method, the design concept does not focus on the powder for 3D printing, and this patent document is to solve problems such as the dissolution of N elements in the preparation process of nitrogen-containing stainless steel, which is different from the design concept of the high-nitrogen and low-nickel alloy powder for 3D printing of the present invention.

[0005] In summary, the density and high-temperature oxidation resistance of alloy powders affect the density and mechanical properties of nickel-based alloy parts. Therefore, it is very important to develop nickel-based alloy materials for 3D printing with high strength, dense powder, and not easy to oxidize. Summary of the Invention

[0006] The object of the present invention is to provide a high-nitrogen and low-nickel alloy powder for 3D printing and a preparation method thereof, overcoming the deficiencies of the prior art. By controlling the chemical composition of the alloy powder and densifying the atomized powder, the density of the prepared high-nitrogen and low-nickel alloy powder for 3D printing is significantly improved, avoiding the influence of powder hollowness on the density of the product. At the same time, the strength and oxidation resistance of the 3D printing alloy at high temperature are improved, enabling it to adapt to various high-temperature application scenarios.

[0007] To achieve the above object, the present invention is realized through the following technical solutions:

[0008] Technical solution one: A high-nitrogen and low-nickel alloy powder for 3D printing, the chemical composition of the alloy powder is as follows by weight percentage: Ni: 45.0 wt%, Cr: 25 wt%, Mn: 7.0 wt%, Si: 1.6 wt%, Mo: 6 wt%, Cu: 0.24 wt%, Co: 0.81 wt%, N: 0.60 wt%, Al: 1.4 wt%, Ti: 1.43 wt%, Nb: 6 wt%, W: 2.6 wt%, V: 1.3 wt%, and the balance is Fe and inevitable impurities.

[0009] Technical solution two: A high-nitrogen and low-nickel alloy powder for 3D printing, the chemical composition of the alloy powder is as follows by weight percentage: Ni: 44.0 wt%, Cr: 26 wt%, Mn: 7.2 wt%, Si: 1.5 wt%, Mo: 6.3 wt%, Cu: 0.23 wt%, Co: 0.83 wt%, N: 0.55 wt%, Al: 1.5 wt%, Ti: 1.45 wt%, Nb: 5.8 wt%, W: 2.7 wt%, V: 1.2 wt%, and the balance is Fe and inevitable impurities.

[0010] Technical solution three: A high-nitrogen and low-nickel alloy powder for 3D printing, the chemical composition of the alloy powder is as follows by weight percentage: Ni: 43.0 wt%, Cr: 24 wt%, Mn: 6.8 wt%, Si: 1.7 wt%, Mo: 6.1 wt%, Cu: 0.25 wt%, Co: 0.86 wt%, N: 0.63 wt%, Al: 1.6 wt%, Ti: 1.41 wt%, Nb: 6.1 wt%, W: 2.6 wt%, V: 1.4 wt%, and the balance is Fe and inevitable impurities.

[0011] Technical Solution 4: A preparation method of high-nitrogen and low-nickel alloy powder for 3D printing, including alloy melting, atomization, and drying steps. First, calculate and weigh the alloy element raw materials according to the chemical composition, where the N element is added in the form of MnN and CrN; then, except for MnN and CrN, select block alloys of Mn, Mo, Cr, V, Al, Ti, Nb, and W with a purity above 99.9% to adjust the ratio of other elements and mix the alloy element raw materials, and use the vacuum melting method to melt them to obtain alloy bars; finally, add the alloy bars into the atomization chamber for atomization treatment to obtain alloy powder, dry the powder, and perform densification treatment on the dried alloy powder. Grind it in a ball mill at a speed of 20-150 r / min for 1-6 hours, where the grinding spheres are alloy spheres of the same composition with a particle size of 20-50 mm. After screening the discharge of the ball mill, the particle size of the high-nitrogen and low-nickel alloy powder for 3D printing obtained is 18-54 μm.

[0012] Further, the atomization treatment includes any one of gas atomization treatment, water atomization treatment, and plasma atomization treatment.

[0013] Further, in the gas atomization treatment, the vacuum degree in the gas atomization chamber is 9.9×10-3 Pa, and the melting temperature is 1100 °C; gas atomization process parameters: rotation speed 4-6 rpm / min; pressure 2-3 MPa; power 35 kW.

[0014] In the present invention, by adding the N element to reduce the Ni element, while reducing the cost, the high-temperature oxidation resistance of the alloy is improved. In terms of the role of the N element, the N element not only has the function of expanding the austenite phase region, but also has the ability to stabilize the austenite structure. At the same time, the N element can also inhibit the activation energy of martensite and deformed martensite, so that the alloy obtains a single austenite structure and ensures the stability of the structure. In the present invention, by adding a densification treatment step in the preparation process, the high-nitrogen and low-nickel alloy powder for 3D printing is prepared, with high sphericity and good density. Due to the reduction of the nickel element content, the cost of the high-nitrogen and low-nickel alloy powder is reduced.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1) By reasonably designing the chemical composition and preparation method of the alloy powder, the present invention prepares high-nitrogen and low-nickel alloy powder for 3D printing, with high sphericity and good density. Since China is a nickel-poor country and nickel resources rely on imports, the price of nickel remains high. Reducing the use content of nickel elements can reduce the cost of high-nitrogen and low-nickel alloy powder by 37.5%;

[0017] 2) While reducing the cost, the density, strength, and oxidation resistance of the alloy are also improved. Description of the Drawings

[0018] Figure 1 Appearance photograph of the high-nitrogen and low-nickel alloy powder for 3D printing prepared in Example 1 of the present invention;

[0019] Figure 2 Microstructure morphology diagram of the high-nitrogen and low-nickel alloy powder for 3D printing in Example 1 of the present invention. Detailed implementation manners

[0020] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are some embodiments of the present invention, rather than all embodiments.

[0021] In order to more clearly illustrate the specific implementation manners of the present invention or the technical solutions in the prior art, the specific embodiments required for use in the description of the specific implementation manners or the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some implementation manners of the present invention. For those of ordinary skill in the art, without creative efforts, other specific embodiments can also be obtained based on these specific embodiments.

[0022] The components of the embodiments of the present invention described and shown here in specific embodiments can be arranged and designed in countless different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in specific embodiments is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0023] Example 1

[0024] The chemical composition of the alloy powder in Example 1 is as follows by weight percentage: Ni: 45.0 wt%, Cr: 25 wt%, Mn: 7.0 wt%, Si: 1.6 wt%, Mo: 6 wt%, Cu: 0.24 wt%, Co: 0.81 wt%, N: 0.60 wt%, Al: 1.4 wt%, Ti: 1.43 wt%, Nb: 6 wt%, W: 2.6 wt%, V: 1.3 wt%, and the balance is Fe and unavoidable impurities.

[0025] The preparation method of Example 1 includes steps of alloy melting, atomization, and drying. First, the alloy element raw materials are calculated and weighed according to the chemical composition. Among them, the N element is added in the form of MnN and CrN. The mass of the metal blocks under each ratio of the orthogonal test is weighed using a BL410F electronic balance (1 mg). All the alloy raw materials are added to a vacuum melting furnace, the furnace lid is sealed, and then vacuum pumping starts. The melting vacuum degree is 9.9×10 -3 Pa, and the melting temperature is 1100 °C; meanwhile, 97% Ar + 3% N2 is filled.

[0026] Then, except for MnN and CrN, select bulk alloys of Mn, Mo, Cr, V, Al, Ti, Nb, and W with a purity above 99.9% to adjust the alloying element raw materials with other element ratios, and melt them by vacuum melting to obtain alloy bars;

[0027] Finally, add the alloy bars into the atomization chamber for atomization treatment. The process parameters of gas atomization are as follows: rotation speed 4 rpm / min; pressure 2.5 MPa; power 35 kW; screen and dry the above-mentioned alloy powder;

[0028] The dried alloy powder is subjected to densification treatment, ground in a ball mill at a speed of 20 - 150 r / min for 1 - 6 hours. The grinding spheres are alloy spheres of the same composition with a particle size of 20 - 50 mm. After screening the discharge of the ball mill, the particle size of the high-nitrogen low-nickel alloy powder for 3D printing is 18 - 54 μm.

[0029] Example 2

[0030] The chemical composition of the alloy powder in Example 2 is as follows by weight percentage: Ni: 44.0 wt%, Cr: 26 wt%, Mn: 7.2 wt%, Si: 1.5 wt%, Mo: 6.3 wt%, Cu: 0.23 wt%, Co: 0.83 wt%, N: 0.55 wt%, Al: 1.5 wt%, Ti: 1.45 wt%, Nb: 5.8 wt%, W: 2.7 wt%, V: 1.2 wt%, and the rest is Fe and inevitable impurities. The preparation process of Example 2 is the same as that of Example 1.

[0031] Example 3

[0032] The chemical composition of the alloy powder in Example 3 is as follows by weight percentage: Ni: 43.0 wt%, Cr: 24 wt%, Mn: 6.8 wt%, Si: 1.7 wt%, Mo: 6.1 wt%, Cu: 0.25 wt%, Co: 0.86 wt%, N: 0.63 wt%, Al: 1.6 wt%, Ti: 1.41 wt%, Nb: 6.1 wt%, W: 2.6 wt%, V: 1.4 wt%, and the rest is Fe and inevitable impurities. The preparation process of Example 3 is the same as that of Example 1.

[0033] Comparative Example

[0034] The alloy composition of the Inconel 625 alloy in the comparative example is: Ni: 63 wt%, Cr: 21.2 wt%, Mn: 0.23 wt%, Si: 0.43 wt%, C: 0.02 wt%, Cu: 0.02 wt%, P: 0.01 wt%, S: 0.006 wt%, Ti: 0.16 wt%, Nb+Ta: 3.50 wt%. The Inconel 625 alloy was subjected to high-temperature oxidation at 1000 °C for 100 h, and the corrosion weight gain was 0.258 mg / mm 2 .

[0035] The alloy powders for 3D printing prepared in Examples 1, 2, 3 and the comparative example were used to obtain printed samples by laser melting deposition (LMD) technology. The process parameters of laser melting deposition were: laser power of 1000 W, scanning speed of 3 mm / s, and powder feeding rate of 2 g / min.

[0036] The high-temperature oxidation weight gain value (mg / cm2), relative density and strength of the printed samples at 1000 °C are shown in Table 1.

[0037] Table 1 High-temperature oxidation weight gain value (mg / cm2), relative density and tensile strength data of the printed samples at 1000 °C

[0038]

[0039]

[0040] As can be seen from Table 1, the high-temperature oxidation weight gain value (mg / cm2), relative density and tensile strength of the printed samples obtained from the alloy powders for 3D printing in Examples 1-3 are generally 10-15% higher than those of the comparative example.

[0041] By comparing the high-temperature oxidation weight gain of Examples 1, 2, and 3, it was found that the oxidation weight gain of Example 1 was the smallest, the addition of N element was moderate, and no pores were found; while in Examples 2 and 3, the oxidation weight gain was larger than that of Example 1. As a surface-active element, N preferentially segregates at grain boundaries. Since the precipitation phase formed by the N element and the Cr element in the low-nickel alloy containing nitrogen is Cr2N, which simultaneously inhibits the formation of Cr 23 C6, less Cr element is consumed, and the N element reduces the range of the Cr-depleted zone, indicating that the presence of an appropriate amount of N element can improve its high-temperature oxidation resistance.

[0042] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made in these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-nitrogen and low-nickel alloy powder for 3D printing, characterized in that, The chemical composition of the alloy powder is as follows by weight percentage: Ni: 45.0 wt%, Cr: 25 wt%, Mn: 7.0 wt%, Si: 1.6 wt%, Mo: 6 wt%, Cu: 0.24 wt%, Co: 0.81 wt%, N: 0.60 wt%, Al: 1.4 wt%, Ti: 1.43 wt%, Nb: 6 wt%, W: 2.6 wt%, V: 1.3 wt%, and the balance is Fe and unavoidable impurities.

2. A high-nitrogen and low-nickel alloy powder for 3D printing, characterized in that, The chemical composition of the alloy powder is as follows by weight percentage: Ni: 44.0 wt%, Cr: 26 wt%, Mn: 7.2 wt%, Si: 1.5 wt%, Mo: 6.3 wt%, Cu: 0.23 wt%, Co: 0.83 wt%, N: 0.55 wt%, Al: 1.5 wt%, Ti: 1.45 wt%, Nb: 5.8 wt%, W: 2.7 wt%, V: 1.2 wt%, and the balance is Fe and unavoidable impurities.

3. A high-nitrogen and low-nickel alloy powder for 3D printing, characterized in that, The chemical composition of the alloy powder is as follows by weight percentage: Ni: 43.0 wt%, Cr: 24 wt%, Mn: 6.8 wt%, Si: 1.7 wt%, Mo: 6.1 wt%, Cu: 0.25 wt%, Co: 0.86 wt%, N: 0.63 wt%, Al: 1.6 wt%, Ti: 1.41 wt%, Nb: 6.1 wt%, W: 2.6 wt%, V: 1.4 wt%, and the balance is Fe and unavoidable impurities.

4. A preparation method of high-nitrogen and low-nickel alloy powder for 3D printing, including alloy melting, atomization, and drying steps. First, calculate and weigh alloy element raw materials according to chemical composition, where the N element is added in the form of MnN and CrN; then, except for MnN and CrN, select Mn, Mo, Cr, V, Al, Ti, Nb, and W bulk alloys with a purity above 99.9% to adjust the alloy element raw materials of other element ratios and mix them, and use vacuum melting method to melt them to obtain alloy bars; finally, add the alloy bars into the atomization chamber for atomization treatment to obtain alloy powder, and dry the powder. It is characterized in that, The dried alloy powder is subjected to densification treatment, ground in a ball mill at a speed of 20 - 150 r / min for 1 - 6 hours, where the grinding spheres are alloy spheres of the same composition with a particle size of 20 - 50 mm. After screening the discharge of the ball mill, the particle size of the high-nitrogen low-nickel alloy powder for 3D printing is 18 - 54 μm.

5. The preparation method of a high-nitrogen and low-nickel alloy powder for 3D printing according to claim 4, wherein The atomization treatment includes any one of gas atomization treatment, water atomization treatment, and plasma atomization treatment.

6. The preparation method of a high-nitrogen and low-nickel alloy powder for 3D printing according to claim 5, characterized in that, In the gas atomization treatment, the vacuum degree in the gas atomization chamber is 9.9×10-3 Pa, and the melting temperature is 1100 °C; the gas atomization process parameters are: rotation speed 4 - 6 rpm / min; pressure 2 - 3 MPa; power 35 kW.

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