A kind of corrosion-resistant alloy iron powder and preparation method thereof

Abstract

The invention relates to the technical field of powder metallurgy, and proposes a corrosion-resistant alloy iron powder and a preparation method thereof, wherein the corrosion-resistant alloy iron powder is composed of the following elements in percentage by mass: C 0.5%-1%, Cr 8%-10%, Ni 1.1%-1.5%, V 2.5%-5.5%, W 6.2%-7.8%, Si 1.2%-1.7%, Nb 2.5%-3.1%, and the remainder is Fe. Through the above technical scheme, the problem of poor corrosion resistance of iron-based powder metallurgy materials in the prior art is solved.

Description

Technical Field

[0001] The invention relates to the technical field of powder metallurgy, and in particular to a corrosion-resistant alloy iron powder and a preparation method thereof. Background Art

[0002] Powder metallurgy is a process technology that produces metal powder or uses metal powder as raw material, and then manufactures metal materials, composite materials and various types of products through molding and sintering. It has the advantages of energy saving, material saving, high product precision and good stability. It is suitable for mass production and is widely used in transportation, machinery, electronics, aerospace, weapons, biology, new energy, information and nuclear industries.

[0003] Among metal powders, iron-based powders are low-cost and easy to shape. Therefore, iron-based powders have the largest production volume and the widest range of applications. For example, iron-based powders are used to form a cladding layer on the surface of mechanical parts using laser cladding rapid prototyping technology to meet the performance requirements of materials under different working conditions of mechanical parts. Corrosion, wear, and fracture are the three major ways to cause material failure. Cladding layers with excellent properties such as corrosion resistance, wear resistance, and fatigue resistance can meet the requirements of various harsh working conditions. However, existing research on iron-based powders only stays at improving hardness and wear resistance, and there is less research on corrosion resistance. At the same time, iron-based powder metallurgy materials have poor corrosion resistance and are difficult to meet the requirements of harsh working conditions such as acid and alkali resistance. Therefore, it is urgent to improve the corrosion resistance of iron-based powder metallurgy materials. Summary of the invention

[0004] The invention provides a corrosion-resistant alloy iron powder and a preparation method thereof, which solves the problem of poor corrosion resistance of iron-based powder metallurgy materials in the prior art.

[0005] The technical solution of the present invention is as follows:

[0006] A corrosion-resistant alloy iron powder is composed of the following elements in percentage by mass: C 0.5%-1%, Cr 8%-10%, Ni1.1%-1.5%, V 2.5%-5.5%, W 6.2%-7.8%, Si 1.2%-1.7%, Nb 2.5%-3.1%, and the balance is Fe.

[0007] As a further technical solution, it is composed of the following elements in mass percentage: C 0.7%-0.8%, Cr 8%-9.3%, Ni1.2-1.4%, V 2.8%-5%, W 6.5%-7.5%, Si 1.5%-1.7%, Nb 2.5%-3%, and the balance is Fe.

[0008] As a further technical solution, the mass ratio of Ni to V is 1:(2.5-3.5).

[0009] As a further technical solution, the mass ratio of Ni to V is 1:3.

[0010] As a further technical solution, the particle size of the corrosion-resistant alloy iron powder is 80-120 μm.

[0011] The present invention also provides a method for preparing the corrosion-resistant alloy iron powder, comprising the following steps:

[0012] S1. preparing raw materials according to the elemental composition of the corrosion-resistant alloy iron powder, and removing impurities on the surface of the raw materials;

[0013] S2, adding raw materials carbon, chromium, silicon, and iron into an electric arc furnace, heating them until they are melted, then transferring them to a refining furnace, adding nickel and tungsten, heating them until they are melted, then adding vanadium and niobium, and keeping them warm after they are completely melted to obtain an alloy melt;

[0014] S3, atomizing the alloy melt by water mist method, and obtaining metal powder after cooling;

[0015] S4. Screening the metal powder to obtain corrosion-resistant alloy iron powder.

[0016] As a further technical solution, the insulation temperature in S2 is 1550-1650° C., and the insulation time is 5-8 minutes.

[0017] As a further technical solution, the atomization pressure in S3 is 10-15 MPa.

[0018] The invention also proposes the application of the corrosion-resistant alloy iron powder in laser melting coating.

[0019] The working principle and beneficial effects of the present invention are:

[0020] 1. In the present invention, elements such as C, Cr, Ni, V, W, Si, and Nb are added to the alloy iron powder. The elements act synergistically with each other. The elements such as C, Cr, and Si significantly improve the hardness of the alloy iron powder through dispersion strengthening and solid solution strengthening. Cr forms carbides with V, W, and Nb, which not only improves the hardness of the alloy iron powder, but also significantly improves the corrosion resistance of the alloy iron powder.

[0021] 2. In the present invention, Ni and V are added to the alloy iron powder, and through long-term experiments, it is found that when the mass ratio of Ni to V in the corrosion-resistant alloy iron powder is 1: (2.5-3.5), the hardness and corrosion resistance of the cladding layer made of the alloy iron powder are significantly improved.

[0022] 3. In the present invention, during the preparation of the alloy iron powder, the order of adding the raw materials is adjusted to promote the full play of the functions of the components in the raw materials, thereby further improving the hardness and corrosion resistance of the cladding layer made of the alloy iron powder. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] A corrosion-resistant alloy iron powder is composed of the following elements in percentage by mass: C 0.5%, Cr 8%, Ni 1.1%, V 2.5%, W 6.2%, Si 1.2%, Nb 2.5%, and the balance is Fe.

[0026] The preparation method comprises the following steps:

[0027] S1. preparing raw materials according to the elemental composition of the corrosion-resistant alloy iron powder, and removing impurities on the surface of the raw materials;

[0028] S2. Add raw materials of carbon, chromium, silicon and iron into an electric arc furnace, heat until melted, then transfer to a refining furnace, add nickel and tungsten, heat until melted, then add vanadium and niobium, and after complete melting, keep the temperature at 1550°C for 8 minutes to obtain an alloy melt;

[0029] S3, using high-pressure water as an atomizing medium to atomize the alloy melt, the atomizing pressure is 10 MPa, and metal powder is obtained after cooling;

[0030] S4. Screening the metal powder to obtain corrosion-resistant alloy iron powder with a particle size of 80-120 μm.

[0031] Example 2

[0032] A corrosion-resistant alloy iron powder is composed of the following elements in percentage by mass: 1% C, 10% Cr, 1.5% Ni, 5.5% V, 7.8% W, 1.7% Si, 3.1% Nb, and the balance is Fe.

[0033] The preparation method comprises the following steps:

[0034] S1. preparing raw materials according to the elemental composition of the corrosion-resistant alloy iron powder, and removing impurities on the surface of the raw materials;

[0035] S2. Add raw materials of carbon, chromium, silicon and iron into an electric arc furnace, heat until melted, then transfer to a refining furnace, add nickel and tungsten, heat until melted, then add vanadium and niobium, and keep warm at 1650°C for 5 minutes after complete melting to obtain alloy melt;

[0036] S3, using high-pressure water as an atomizing medium to atomize the alloy melt, the atomizing pressure is 12 MPa, and metal powder is obtained after cooling;

[0037] S4. Screening the metal powder to obtain corrosion-resistant alloy iron powder with a particle size of 80-120 μm.

[0038] Example 3

[0039] A corrosion-resistant alloy iron powder is composed of the following elements in percentage by mass: C 0.7%, Cr 8%, Ni 1.2%, V 2.8%, W 6.5%, Si 1.5%, Nb 2.5%, and the balance is Fe.

[0040] The preparation method comprises the following steps:

[0041] S1. preparing raw materials according to the elemental composition of the corrosion-resistant alloy iron powder, and removing impurities on the surface of the raw materials;

[0042] S2, adding raw materials carbon, chromium, silicon, and iron into an electric arc furnace, heating them until they are melted, then transferring them to a refining furnace, adding nickel and tungsten, heating them until they are melted, then adding vanadium and niobium, and after they are completely melted, keeping the temperature at 1600° C. for 6 minutes to obtain an alloy melt;

[0043] S3, using high-pressure water as an atomizing medium to atomize the alloy melt, the atomizing pressure is 15 MPa, and metal powder is obtained after cooling;

[0044] S4. Screening the metal powder to obtain corrosion-resistant alloy iron powder with a particle size of 80-120 μm.

[0045] Example 4

[0046] A corrosion-resistant alloy iron powder is composed of the following elements in percentage by mass: 0.8% C, 9.3% Cr, 1.4% Ni, 5% V, 7.5% W, 1.7% Si, 3% Nb, and the balance is Fe.

[0047] The preparation method comprises the following steps:

[0048] S1. preparing raw materials according to the elemental composition of the corrosion-resistant alloy iron powder, and removing impurities on the surface of the raw materials;

[0049] S2, adding raw materials carbon, chromium, silicon, and iron into an electric arc furnace, heating them until they are melted, then transferring them to a refining furnace, adding nickel and tungsten, heating them until they are melted, then adding vanadium and niobium, and after they are completely melted, keeping the temperature at 1600° C. for 6 minutes to obtain an alloy melt;

[0050] S3, using high-pressure water as an atomizing medium to atomize the alloy melt, the atomizing pressure is 15 MPa, and metal powder is obtained after cooling;

[0051] S4. Screening the metal powder to obtain corrosion-resistant alloy iron powder with a particle size of 80-120 μm.

[0052] Example 5

[0053] A corrosion-resistant alloy iron powder, composed of the following elements in percentage by mass: C 0.7%, Cr 8%, Ni 1.2%, V 3%, W 6.5%, Si 1.5%, Nb 2.5%, and the balance Fe;

[0054] The preparation method comprises the following steps:

[0055] S1. preparing raw materials according to the elemental composition of the corrosion-resistant alloy iron powder, and removing impurities on the surface of the raw materials;

[0056] S2, adding raw materials carbon, chromium, silicon, and iron into an electric arc furnace, heating them until they are melted, then transferring them to a refining furnace, adding nickel and tungsten, heating them until they are melted, then adding vanadium and niobium, and after they are completely melted, keeping the temperature at 1600° C. for 6 minutes to obtain an alloy melt;

[0057] S3, using high-pressure water as an atomizing medium to atomize the alloy melt, the atomizing pressure is 3 MPa, and metal powder is obtained after cooling;

[0058] S4. Screening the metal powder to obtain corrosion-resistant alloy iron powder with a particle size of 80-120 μm.

[0059] Example 6

[0060] A corrosion-resistant alloy iron powder, composed of the following elements in percentage by mass: C 0.7%, Cr 8%, Ni 1.2%, V 3.6%, W 6.5%, Si 1.5%, Nb 2.5%, and the balance Fe;

[0061] The preparation method comprises the following steps:

[0062] S1. preparing raw materials according to the elemental composition of the corrosion-resistant alloy iron powder, and removing impurities on the surface of the raw materials;

[0063] S2, adding raw materials carbon, chromium, silicon, and iron into an electric arc furnace, heating them until they are melted, then transferring them to a refining furnace, adding nickel and tungsten, heating them until they are melted, then adding vanadium and niobium, and after they are completely melted, keeping the temperature at 1600° C. for 6 minutes to obtain an alloy melt;

[0064] S3, using high-pressure water as an atomizing medium to atomize the alloy melt, the atomizing pressure is 15 MPa, and metal powder is obtained after cooling;

[0065] S4. Screening the metal powder to obtain corrosion-resistant alloy iron powder with a particle size of 80-120 μm.

[0066] Example 7

[0067] A corrosion-resistant alloy iron powder, composed of the following elements in percentage by mass: C 0.7%, Cr 8%, Ni 1.2%, V 4.2%, W 6.5%, Si 1.5%, Nb 2.5%, and the balance Fe;

[0068] The preparation method comprises the following steps:

[0069] S1. preparing raw materials according to the elemental composition of the corrosion-resistant alloy iron powder, and removing impurities on the surface of the raw materials;

[0070] S2, adding raw materials carbon, chromium, silicon, and iron into an electric arc furnace, heating them until they are melted, then transferring them to a refining furnace, adding nickel and tungsten, heating them until they are melted, then adding vanadium and niobium, and after they are completely melted, keeping the temperature at 1600° C. for 6 minutes to obtain an alloy melt;

[0071] S3, using high-pressure water as an atomizing medium to atomize the alloy melt, the atomizing pressure is 15 MPa, and metal powder is obtained after cooling;

[0072] S4. Screening the metal powder to obtain corrosion-resistant alloy iron powder with a particle size of 80-120 μm.

[0073] Comparative Example 1

[0074] A corrosion-resistant alloy iron powder, the element composition of which is the same as that of Example 1;

[0075] The preparation method comprises the following steps:

[0076] S1. preparing raw materials according to the elemental composition of the corrosion-resistant alloy iron powder, and removing impurities on the surface of the raw materials;

[0077] S2. Add raw materials of carbon, chromium, silicon, iron, nickel and tungsten into an electric arc furnace, heat until melted, then transfer to a refining furnace, add vanadium and niobium, and keep the temperature at 1600°C for 6 minutes after complete melting to obtain an alloy melt;

[0078] S3, using high-pressure water as an atomizing medium to atomize the alloy melt, the atomizing pressure is 15 MPa, and metal powder is obtained after cooling;

[0079] S4. Screening the metal powder to obtain corrosion-resistant alloy iron powder with a particle size of 80-120 μm.

[0080] Comparative Example 2

[0081] A corrosion-resistant alloy iron powder, the element composition of which is the same as that of Example 1;

[0082] The preparation method comprises the following steps:

[0083] S1. preparing raw materials according to the elemental composition of the corrosion-resistant alloy iron powder, and removing impurities on the surface of the raw materials;

[0084] S2. Add 50% carbon, 40% chromium, 40% iron and 40% nickel in the raw materials into an electric arc furnace, heat until melted, continue to add 50% carbon, 30% chromium, 30% iron and 30% nickel, continue to add 30% chromium, 30% iron and 30% nickel after melting, transfer to a refining furnace after complete melting, add all tungsten and all silicon, add all vanadium and all niobium after complete melting, keep warm at 1600°C for 6 minutes after complete melting to obtain alloy melt;

[0085] S3, using high-pressure water as an atomizing medium to atomize the alloy melt, the atomizing pressure is 15 MPa, and metal powder is obtained after cooling;

[0086] S4. Screening the metal powder to obtain corrosion-resistant alloy iron powder with a particle size of 80-120 μm.

[0087] Comparative Example 3

[0088] A corrosion-resistant alloy iron powder, the element composition of which is the same as that of Example 1;

[0089] The preparation method comprises the following steps:

[0090] S1. preparing raw materials according to the elemental composition of the corrosion-resistant alloy iron powder, and removing impurities on the surface of the raw materials;

[0091] S2. Add the raw material components into the electric arc furnace, transfer them to the refining furnace after they are completely melted, and keep them at 1600°C for 6 minutes to obtain alloy melt;

[0092] S3, using high-pressure water as an atomizing medium to atomize the alloy melt, the atomizing pressure is 15 MPa, and metal powder is obtained after cooling;

[0093] S4. Screening the metal powder to obtain corrosion-resistant alloy iron powder with a particle size of 80-120 μm.

[0094] The corrosion-resistant alloy iron powder prepared in Examples 1-7 and Comparative Examples 1-3 was laser clad on a steel substrate to obtain laser rapid prototyping specimens, wherein the thickness of the cladding layer formed by the corrosion-resistant alloy iron powder was 2 mm, and the surface of the steel substrate was cleaned with acetone before cladding. The parameters of the laser cladding were: scanning speed 5 mm / s, laser power 4 kW, argon protection, and powder feeding rate 50 g / min.

[0095] The samples of Examples 1-7 and Comparative Examples 1-3 were subjected to the following hardness test and corrosion resistance test:

[0096] (1) Hardness test: Test the hardness of the specimen according to the method specified in GB / T 21838.4-2020 "Instrumented indentation test for hardness and material parameters of metallic materials Part 4: Test methods for metallic and non-metallic coatings";

[0097] (2) Corrosion resistance test: The corrosion resistance of the test specimen is tested by the neutral salt spray test specified in GB / T 10125-2012 “Artificial atmosphere corrosion test salt spray test”.

[0098] The test results are shown in the table below:

[0099] Table 1 Performance test results of the cladding layers formed by the corrosion-resistant alloy iron powders of Examples 1-7 and Comparative Examples 1-3

[0100]

[0101] From the data in the above table, it can be seen that the hardness of the cladding layer formed by the corrosion-resistant alloy iron powder of Examples 1-7 is as high as 865-923 HV 0.5 The salt spray resistance time is as long as 720-1500h, which shows that the corrosion-resistant alloy iron powder of the present invention has high hardness and good corrosion resistance.

[0102] Compared with Example 4, the hardness and salt spray resistance time of Examples 5-7 are significantly increased, indicating that when the mass ratio of Ni to V in the corrosion-resistant alloy iron powder is 1: (2.5-3.5), the hardness and corrosion resistance of the alloy iron powder are significantly improved.

[0103] Compared with comparative examples 1-3, the salt spray resistance time of Example 1 is significantly increased, indicating that the preparation method of the present invention can fully exert the efficacy of each component in the raw materials by adding the raw materials step by step, thereby further improving the hardness and corrosion resistance of the alloy iron powder.

[0104] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A corrosion-resistant iron alloy powder, characterized in that: Composed of the following elements in mass percentage: C 0.5%-1%, Cr8%-10%, Ni 1.1%-1.5%, V 2.5%-5.5%, W 6.2%-7.8%, Si 1.2%-1.7%, Nb 2.5%-3.1%, and the balance is Fe; the mass ratio of Ni to V is 1:(2.5-3.5); The method for preparing the corrosion-resistant alloy iron powder comprises the following steps: S1. preparing raw materials according to the elemental composition of the corrosion-resistant alloy iron powder, and removing impurities on the surface of the raw materials; S2, adding raw materials carbon, chromium, silicon, and iron into an electric arc furnace, heating them until they are melted, then transferring them to a refining furnace, adding nickel and tungsten, heating them until they are melted, then adding vanadium and niobium, and keeping them warm after they are completely melted to obtain an alloy melt; S3, atomizing the alloy melt by water mist method, and obtaining metal powder after cooling; S4. Screening the metal powder to obtain corrosion-resistant alloy iron powder.

2. The corrosion-resistant iron alloy powder according to claim 1, characterized in that: It is composed of the following elements in percentage by mass: C 0.7%-0.8%, Cr 8%-9.3%, Ni 1.1%-1.4%, V 2.8%-5%, W 6.5%-7.5%, Si 1.5%-1.7%, Nb 2.5%-3%, and the balance is Fe.

3. The corrosion-resistant iron alloy powder according to claim 1, characterized in that: The mass ratio of Ni to V is 1:

3.

4. The corrosion-resistant iron alloy powder according to claim 1, characterized in that: The particle size of the corrosion-resistant alloy iron powder is 80-120 μm.

5. The method for preparing the corrosion-resistant alloy iron powder according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. preparing raw materials according to the elemental composition of the corrosion-resistant alloy iron powder, and removing impurities on the surface of the raw materials; S2, adding raw materials carbon, chromium, silicon, and iron into an electric arc furnace, heating them until they are melted, then transferring them to a refining furnace, adding nickel and tungsten, heating them until they are melted, then adding vanadium and niobium, and keeping them warm after they are completely melted to obtain an alloy melt; S3, atomizing the alloy melt by water mist method, and obtaining metal powder after cooling; S4. Screening the metal powder to obtain corrosion-resistant alloy iron powder.

6. The method for preparing a corrosion-resistant alloy iron powder according to claim 5, characterized in that: The insulation temperature in S2 is 1550-1650° C., and the insulation time is 5-8 minutes.

7. The method for preparing a corrosion-resistant alloy iron powder according to claim 5, characterized in that: The atomization pressure in S3 is 10-15MPa.

8. An application of corrosion-resistant alloy iron powder, characterized in that: Use of the corrosion-resistant alloy iron powder described in any one of claims 1 to 4 or the corrosion-resistant alloy iron powder obtained by the preparation method described in any one of claims 5 to 7 in laser melting coating.

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