Method for improving cavitation erosion resistance of fe-mn-al-c light weight steel

Abstract

This invention belongs to the field of alloy materials technology and discloses a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel. The method involves: pretreating the Fe-Mn-Al-C lightweight steel to remove dust and impurities from its surface, obtaining pretreated Fe-Mn-Al-C lightweight steel; and then subjecting the surface of the pretreated Fe-Mn-Al-C lightweight steel to electron beam remelting under vacuum conditions to form a cladding layer on the surface of the pretreated Fe-Mn-Al-C lightweight steel, thereby improving its cavitation erosion resistance. This invention involves pretreating Fe-Mn-Al-C lightweight steel and then subjecting it to electron beam remelting. The electron beam remelting process alters the surface roughness and structure of the Fe-Mn-Al-C lightweight steel, causing the surface grains to form equiaxed and columnar crystals under the influence of the electron beam. This results in the formation of a dense and more uniform cladding layer on the surface of the Fe-Mn-Al-C lightweight steel, which not only improves the surface hardness and strength of the Fe-Mn-Al-C steel but also enhances its wear resistance, corrosion resistance, and cavitation erosion resistance.

Description

Technical Field

[0001] This invention relates to the field of alloy materials technology, and in particular to a method for improving the cavitation resistance of Fe-Mn-Al-C lightweight steel. Background Technology

[0002] Fe-Mn-Al-C lightweight steel is a novel lightweight alloy. Compared to ordinary steels, it has a higher content of Al and Mn elements, thus altering the steel's smelting and subsequent processing techniques, particularly the evolution and control of microstructure and the strengthening and toughening mechanisms. Currently, most reports on this system of lightweight steels are based on laboratory research data, with few industrial applications. This is because current research on low-density steels, both domestically and internationally, primarily focuses on thermodynamic calculations and related theories, austenite stability, B2 / DO3 / κ-carbide precipitation characteristics, and strength and toughness mechanisms, while its cavitation erosion properties require further investigation. Based on current research on lightweight steels, high-Al content Fe-Mn-Al-C lightweight steel exhibits excellent weight reduction potential, high strength-plasticity product, strain hardening, and high energy absorption, making it one of the most promising lightweight steel types.

[0003] Fe-Mn-Al-C lightweight steel, due to its light weight, high strength, and certain corrosion resistance, has great application potential in flow-through components such as turbine blades and valve stems. However, it faces cavitation damage during service, reducing its service life. Macroscopically, the large addition of Al in Fe-Mn-Al-C lightweight steel complicates metallurgical issues, making continuous casting impossible and limiting its industrial application. Extensive and in-depth research is needed on the processing technology of Fe-Mn-Al-C steel to provide effective parameters for practical industrial applications. Controlling precipitates to achieve reinforcement and toughening of Fe-Mn-Al-C lightweight steel and improve its practical performance is of great significance.

[0004] Therefore, the present invention provides a method for improving the cavitation resistance of Fe-Mn-Al-C lightweight steel. Summary of the Invention

[0005] To address the shortcomings of the existing technology, this invention provides a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel. First, the Fe-Mn-Al-C lightweight steel is pretreated to remove dust and impurities from its surface. Then, the pretreated Fe-Mn-Al-C lightweight steel is subjected to electron beam remelting under vacuum conditions. This electron beam remelting process alters the surface roughness and structure of the Fe-Mn-Al-C lightweight steel, causing the surface grains to form equiaxed and columnar crystals under the action of the electron beam. This results in the in-situ formation of a dense and more uniform cladding layer on the surface of the Fe-Mn-Al-C lightweight steel. The formed cladding layer has high density, which not only improves the surface hardness and strength of the Fe-Mn-Al-C steel but also enhances its wear resistance, corrosion resistance, and cavitation erosion resistance.

[0006] The present invention provides a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel through the following technical solution:

[0007] A method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel includes the following steps:

[0008] Fe-Mn-Al-C light steel is pretreated to remove dust and impurities from its surface, thereby obtaining pretreated Fe-Mn-Al-C light steel.

[0009] Under vacuum conditions, the surface of the pretreated Fe-Mn-Al-C lightweight steel is subjected to electron beam remelting treatment to form a cladding layer on the surface of the pretreated Fe-Mn-Al-C lightweight steel, thereby improving the cavitation resistance of the Fe-Mn-Al-C lightweight steel.

[0010] Preferably, the thickness of the cladding layer is 70–150 μm.

[0011] Preferably, the scanning speed of the electron beam remelting process is 1.000 to 5.000 m / s, the current intensity is 1.0 to 20.0 mA, and the defocusing amount is -0.100 to -0.500 V.

[0012] Preferably, the scanning speed of the electron beam remelting process is 2.000 to 3.000 m / s, the current intensity is 5.0 to 15.0 mA, and the defocusing amount is -0.200 to -0.500 V.

[0013] Preferably, the scanning speed of the electron beam remelting process is 2.600 m / s, the current intensity is 10.0 to 12.0 mA, and the defocusing amount is -0.250 to -0.500 V.

[0014] Preferably, the Fe-Mn-Al-C light steel in the cladding layer has equiaxed and columnar crystal structures.

[0015] Preferably, the vacuum degree during the electron beam remelting process is 10. -2 ~10 -4 Pa.

[0016] Preferably, the preprocessing includes the following steps:

[0017] The surface of the Fe-Mn-Al-C lightweight steel was successively ground and polished; then the polished Fe-Mn-Al-C lightweight steel was immersed in ethanol for ultrasonic treatment and then dried.

[0018] Preferably, the polishing process involves polishing the surface of the Fe-Mn-Al-C lightweight steel with sandpaper until the surface roughness of the Fe-Mn-Al-C lightweight steel is 0.1 to 0.05.

[0019] Preferably, the sandpaper is 400-2500# wet sandpaper.

[0020] Preferably, the polishing process is performed using a polishing slurry; and the polishing rotation speed is 350–400 r / min.

[0021] Preferably, the polishing fluid is a diamond polishing fluid.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] This invention first pre-treats Fe-Mn-Al-C lightweight steel to remove dust and impurities from its surface. Then, the pre-treated Fe-Mn-Al-C lightweight steel undergoes electron beam remelting under vacuum conditions. This electron beam remelting process alters the surface roughness and structure of the Fe-Mn-Al-C lightweight steel, causing the surface grains to form equiaxed and columnar crystals under the influence of the electron beam. This results in the formation of a dense and more uniform cladding layer on the surface of the Fe-Mn-Al-C lightweight steel. The resulting cladding layer exhibits high density, which not only improves the surface hardness and strength of the Fe-Mn-Al-C steel but also enhances its wear resistance, corrosion resistance, and cavitation erosion resistance. The processing method of this invention is simple and easy to operate, making it suitable for industrial production.

[0024] The surface layer of Fe-Mn-Al-C steel treated by the method of this invention becomes denser, and its surface hardness and strength are significantly improved. Furthermore, the surface roughness and surface structure of the Fe-Mn-Al-C steel treated by this invention are altered, the density of the surface layer is greatly increased, and the microstructure of the surface layer is more uniform. This significantly improves the cavitation erosion resistance, wear resistance, and corrosion resistance of the Fe-Mn-Al-C steel, enabling its use in harsh environments. In addition, electron beam remelting can also improve the mechanical properties of the metal, thereby better meeting the needs of different fields, such as for manufacturing high-strength structural parts in automobile wheels, tires, and bridges. Attached Figure Description

[0025] Figure 1 The images show the XRD patterns of the original Fe-Mn-Al-C lightweight steel, as well as the Fe-Mn-Al-C lightweight steels of Example 1 and Comparative Example 1.

[0026] Figure 2 This is a SEM image of the sample after cavitation in Example 1.

[0027] Figure 3 The image shows the SEM image of the sample after cavitation in Comparative Example 1.

[0028] Figure 4 The image shows the SEM image of the sample after cavitation in Comparative Example 2.

[0029] Figure 5 The image shows the SEM image of the sample in Comparative Example 3 after cavitation.

[0030] Figure 6 The image shows the SEM image of the sample in Comparative Example 4 after cavitation.

[0031] Figure 7 The results are the hardness test results of Fe-Mn-Al-C lightweight steels in Examples 1-2 and Comparative Examples 1-4. Detailed Implementation

[0032] This invention addresses the limitation of traditional Fe-Mn-Al-C lightweight steel in its application to marine turbines due to its poor cavitation resistance. To address this limitation, this invention proposes using electron beam remelting technology to modify the surface of Fe-Mn-Al-C lightweight steel, thereby forming a dense cladding layer in situ on the surface. This improves the density, wear resistance, and corrosion resistance of the surface layer, significantly enhancing the mechanical properties of the Fe-Mn-Al-C lightweight steel.

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below.

[0034] This invention provides a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel, comprising the following steps:

[0035] Step 1: Pre-treat the Fe-Mn-Al-C light steel to remove dust and impurities from the surface of the Fe-Mn-Al-C light steel, and obtain pre-treated Fe-Mn-Al-C light steel.

[0036] It should be noted that, considering the presence of impurities and dust on the surface of Fe-Mn-Al-C lightweight steel, which is detrimental to the formation of a cladding layer during subsequent electron beam remelting, the present invention pre-treats the Fe-Mn-Al-C lightweight steel before electron beam remelting to remove dust and impurities from its surface. This improves the purity of the cladding layer during subsequent electron beam remelting, thereby effectively enhancing the density of the surface layer of the Fe-Mn-Al-C lightweight steel and improving its mechanical properties.

[0037] To ensure the removal of dust and impurities from the surface of Fe-Mn-Al-C lightweight steel, in a preferred embodiment of the present invention, the pretreatment includes the following steps: grinding and polishing the surface of the Fe-Mn-Al-C lightweight steel in sequence; then immersing the polished Fe-Mn-Al-C lightweight steel in ethanol for ultrasonic treatment and drying it.

[0038] In another preferred embodiment of the present invention, the polishing process involves polishing the surface of the Fe-Mn-Al-C light steel with sandpaper until the surface roughness of the Fe-Mn-Al-C light steel is 0.1 to 0.05, so as to initially remove dust and impurities from the surface of the Fe-Mn-Al-C light steel.

[0039] In another preferred embodiment of the present invention, the sandpaper is 400-2500# wet sandpaper.

[0040] In another preferred embodiment of the present invention, the polishing process is performed using a polishing liquid; and the polishing speed is 350-400 r / min.

[0041] Furthermore, in another preferred embodiment of the present invention, the polishing fluid is a diamond polishing fluid.

[0042] Step 2: Under vacuum conditions, the surface of the pretreated Fe-Mn-Al-C light steel is subjected to electron beam remelting treatment to form a cladding layer on the surface of the pretreated Fe-Mn-Al-C light steel, thereby improving the cavitation resistance of the Fe-Mn-Al-C light steel.

[0043] It should be noted that this invention takes into account that electron beam remelting should be performed under vacuum; therefore, a vacuum degree of 10 is used. -2 ~10 -4 Electron beam remelting is performed within the vacuum chamber of Pa.

[0044] To ensure that the mechanical properties of Fe-Mn-Al-C lightweight steel, especially its cavitation resistance, can be improved through electron beam remelting treatment of the surface, in a preferred embodiment of the present invention, the process parameters for electron beam remelting treatment are: scanning speed of 1.000–5.000 m / s, current intensity of 1.0–20.0 mA, and defocusing amount of -0.100–-0.500 V. In another preferred embodiment of the present invention, the process parameters for electron beam remelting treatment are more preferably: scanning speed of 2.000–3.000 m / s, current intensity of 5.0–15.0 mA, and defocusing amount of -0.200–-0.500 V.

[0045] To further ensure that the treatment of Fe-Mn-Al-C lightweight steel surface layer can be significantly improved by the present invention, in another preferred embodiment of the present invention, the scanning speed of the electron beam remelting treatment is 2.600 m / s, the current intensity is 10.0 to 12.0 mA, and the defocusing amount is -0.250 to -0.500 V.

[0046] Example 1

[0047] This embodiment provides a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel, including the following steps:

[0048] Step 1, cut the sample:

[0049] The Fe-Mn-Al-C light steel to be treated was cut into samples with a size of 20×20mm for later use;

[0050] Step 2, Pre-treatment of the sample:

[0051] First, use fine sandpaper to polish the Fe-Mn-Al-C light steel sample obtained in step 1 above until the surface roughness is 0.1 to 0.05, so as to obtain a smooth surface;

[0052] The sample after the above grinding treatment was then polished with diamond polishing fluid to remove dust and impurities from the surface of the Fe-Mn-Al-C light steel sample, thus obtaining the pretreated Fe-Mn-Al-C light steel sample.

[0053] Step 3, Electron beam remelting:

[0054] The Fe-Mn-Al-C lightweight steel sample obtained in step 2 was placed in a Y150 powder bed electron beam printer, a vacuum was drawn, and then the process parameters for electron beam remelting were set as follows: scanning speed of 2.600 m / s, current intensity of 12.0 mA, and defocusing amount of -0.500 V, thereby improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel.

[0055] Example 2

[0056] This embodiment provides a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel, including the following steps:

[0057] Step 1, cut the sample:

[0058] The Fe-Mn-Al-C light steel to be treated was cut into samples with a size of 20×20mm for later use;

[0059] Step 2, Pre-treatment of the sample:

[0060] First, use fine sandpaper to polish the Fe-Mn-Al-C light steel sample obtained in step 1 above until the surface roughness is 0.1 to 0.05, so as to obtain a smooth surface;

[0061] The sample after the above grinding treatment is then polished with diamond polishing fluid to remove dust and impurities from the surface of the Fe-Mn-Al-C light steel sample, thus obtaining the pretreated Fe-Mn-Al-C light steel sample.

[0062] Step 3, Electron beam remelting:

[0063] The Fe-Mn-Al-C lightweight steel sample obtained in step 2 was placed in a Y150 powder bed electron beam printer, a vacuum was drawn, and then the process parameters for electron beam remelting were set as follows: scanning speed of 2.600 m / s, current intensity of 10.0 mA, and defocusing amount of -0.250 V, thereby improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel.

[0064] Example 3

[0065] This embodiment provides a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel. The only difference between this comparative example and Example 1 is that:

[0066] In this embodiment, the scanning speed of the electron beam remelting process is 1.000 m / s, the current intensity is 1.0 mA, and the defocusing amount is -0.100 V.

[0067] Example 4

[0068] This embodiment provides a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel. The only difference between this comparative example and Example 1 is that:

[0069] In this embodiment, the scanning speed of the electron beam remelting process is 5.000 m / s, the current intensity is 20.0 mA, and the defocusing amount is -0.500 V.

[0070] Example 5

[0071] This embodiment provides a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel. The only difference between this comparative example and Example 1 is that:

[0072] In this embodiment, the scanning speed of the electron beam remelting process is 2.000 m / s, the current intensity is 5.0 mA, and the defocusing amount is -0.200 V.

[0073] Example 6

[0074] This embodiment provides a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel. The only difference between this comparative example and Example 1 is that:

[0075] In this embodiment, the scanning speed of the electron beam remelting process is 3.000 m / s, the current intensity is 15.0 mA, and the defocusing amount is -0.300 V.

[0076] Comparative Example 1

[0077] This comparative example provides a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel, comprising the following steps:

[0078] Step 1, cut the sample:

[0079] The Fe-Mn-Al-C light steel to be treated was cut into samples with a size of 20×20mm for later use;

[0080] Step 2, Pre-treatment of the sample:

[0081] First, use fine sandpaper to polish the Fe-Mn-Al-C light steel sample obtained in step 1 above until the surface roughness is 0.1 to 0.05, so as to obtain a smooth surface;

[0082] The sample after the above grinding treatment was polished with diamond polishing fluid to remove dust and impurities from the surface of the Fe-Mn-Al-C light steel sample, thus obtaining the pretreated Fe-Mn-Al-C light steel sample.

[0083] Step 3, heat treatment:

[0084] The Fe-Mn-Al-C light steel sample obtained in step 2 was placed in a reaction furnace and kept at 800℃ for 8 hours.

[0085] In other words, the only difference between this comparative example and Example 1 is that:

[0086] This comparative example uses heat treatment instead of electron beam remelting.

[0087] Furthermore, the heat treatment temperature in this comparative example was 800℃, and the heat treatment time was 8h.

[0088] Comparative Example 2

[0089] This comparative example provides a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel, comprising the following steps:

[0090] Step 1, cut the sample:

[0091] The Fe-Mn-Al-C light steel to be treated was cut into samples with a size of 20×20mm for later use;

[0092] Step 2, Pre-treatment of the sample:

[0093] First, use fine sandpaper to polish the Fe-Mn-Al-C light steel sample obtained in step 1 above until the surface roughness is 0.1 to 0.05, so as to obtain a smooth surface;

[0094] The sample after the above grinding treatment is then polished with diamond polishing fluid to remove dust and impurities from the surface of the Fe-Mn-Al-C light steel sample, so as to obtain the pretreated Fe-Mn-Al-C light steel sample as the final sample.

[0095] In other words, the only difference between this comparative example and Example 1 is that:

[0096] This comparative example omits the electron beam remelting treatment of Fe-Mn-Al-C light steel.

[0097] Comparative Example 3

[0098] This comparative example provides a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel, comprising the following steps:

[0099] Step 1, cut the sample:

[0100] The Fe-Mn-Al-C light steel to be treated was cut into samples with a size of 20×20mm for later use;

[0101] Step 2, Pre-treatment of the sample:

[0102] First, use fine sandpaper to polish the Fe-Mn-Al-C light steel sample obtained in step 1 above until the surface roughness is 0.1 to 0.05, so as to obtain a smooth surface;

[0103] The sample after the above grinding treatment is then polished with diamond polishing fluid to remove dust and impurities from the surface of the Fe-Mn-Al-C light steel sample, thus obtaining the pretreated Fe-Mn-Al-C light steel sample.

[0104] Step 3, Electron beam remelting:

[0105] The Fe-Mn-Al-C lightweight steel sample obtained in step 2 was placed in a Y150 powder bed electron beam printer, a vacuum was drawn, and then the process parameters for electron beam remelting were set as follows: scanning speed of 0.500 m / s, current intensity of 25.0 mA, and defocusing amount of -1.000 V, thereby improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel.

[0106] In other words, the only difference between this comparative example and Example 1 is that:

[0107] The process parameters for electron beam remelting in this comparative example are not within the scope of this invention.

[0108] The scanning speed is 0.500 m / s, the current intensity is 25.0 mA, and the defocusing amount is -1.000 V.

[0109] Comparative Example 4

[0110] This comparative example provides a method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel, comprising the following steps:

[0111] Step 1, cut the sample:

[0112] The Fe-Mn-Al-C light steel to be treated was cut into samples with a size of 20×20mm for later use;

[0113] Step 2, Pre-treatment of the sample:

[0114] First, use fine sandpaper to polish the Fe-Mn-Al-C light steel sample obtained in step 1 above until the surface roughness is 0.1 to 0.05, so as to obtain a smooth surface;

[0115] The sample after the above grinding treatment is then polished with diamond polishing fluid to remove dust and impurities from the surface of the Fe-Mn-Al-C light steel sample, thus obtaining the pretreated Fe-Mn-Al-C light steel sample.

[0116] Step 3, Electron beam remelting:

[0117] The Fe-Mn-Al-C lightweight steel sample obtained in step 2 was placed in a Y150 powder bed electron beam printer, a vacuum was drawn, and then the process parameters for electron beam remelting were set as follows: tracing speed of 6.000 m / s, current intensity of 0.50 mA, and defocusing amount of 1.000 V, thereby improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel.

[0118] In other words, the only difference between this comparative example and Example 1 is that:

[0119] The process parameters for electron beam remelting in this comparative example are not within the scope of this invention.

[0120] The scanning speed is 6.000 m / s, the current intensity is 0.50 mA, and the defocusing amount is 1.000 V.

[0121] Comparative Example 5

[0122] The only difference between this comparative example and Example 1 is that:

[0123] No treatment was performed, i.e., the original Fe-Mn-Al-C light steel without any treatment was used as a control.

[0124] Experimental Section

[0125] (I) Cavitation Resistance Test

[0126] The present invention takes the samples obtained by Example 1 and Comparative Examples 1-4 as examples, and conducts cavitation erosion experiments respectively, and the test results are shown in Table 1 below.

[0127] Table 1. Cavitation erosion test results of the samples obtained from Example 1 and Comparative Examples 1-4.

[0128] Example 1 9 5.3 0.59 Example 2 9 5.9 0.66 Comparative Example 1 9 8.0 0.89 Comparative Example 2 9 13.8 1.53 Comparative Example 3 9 15.3 1.7 Comparative Example 4 9 14.6 1.6

[0129] The cavitation erosion experiment of the present invention is carried out through the following steps:

[0130] The cavitation testing equipment was an XOQS-1000 ultrasonic material cavitation testing machine. The amplitude transformer vibrating head was 2 mm away from the sample, and an ultrasonic frequency of 20 kHz was used. The experimental temperature was controlled at 25 ± 2℃ using an XODC-100F high-precision cryogenic circulator. The cumulative cavitation time was 9 hours. Weighing was performed using a FA2004 electronic balance with a precision of 0.1 mg at the beginning of cavitation, and at 0.5 h, 1 h, 1.5 h, 2.5 h, 3.5 h, 4.5 h, 5.5 h, 6.5 h, 7.5 h, and 9 h of cavitation. The cumulative mass loss was recorded to determine the cavitation rate of the alloy during the cavitation process.

[0131] According to the test results in Table 1, the total cavitation mass loss of the sample in Example 1 was 5.3 mg, and the cavitation rate was 0.59 mg / h; the total cavitation mass loss of the sample in Example 2 was 5.9 mg, and the cavitation rate was 0.66 mg / h; while the total cavitation mass loss of the sample in Comparative Example 1 was 8.0 mg, and the cavitation rate was 0.89 mg / h; the total cavitation mass loss of the sample in Comparative Example 2 was 13.8 mg, and the cavitation rate was 1.53 mg / h; the total cavitation mass loss of the sample in Comparative Example 3 was 15.3 mg, and the cavitation rate was 1.7 mg / h; and the total cavitation mass loss of the sample in Comparative Example 4 was 14.6 mg, and the cavitation rate was 1.6 mg / h. It can be seen that the total cavitation mass loss of Examples 1 and 2 is significantly less than that of Comparative Examples 1-4, indicating that the method of the present invention can significantly improve the cavitation resistance of Fe-Mn-Al-C lightweight steel.

[0132] Furthermore, the total mass loss and cavitation rate of the samples in Examples 1 and 2 were similar. This may be because after the treatment of the present invention, the grain size of the Fe-Mn-Al-C light steel surface structure becomes smaller and the grain boundaries increase, which improves the hardness and strength of the Fe-Mn-Al-C light steel material, thereby reducing the mass loss rate and improving the cavitation resistance of Fe-Mn-Al-C light steel.

[0133] By comparing the test results of Example 1 and Comparative Example 1, it can be seen that, compared with Example 1, the total mass loss and cavitation rate of the sample in Comparative Example 1 both increased. The mass loss rate was relatively slow, and the mass loss increased over time until the end of the cavitation experiment. This indicates that electron beam remelting treatment can significantly improve the cavitation resistance of Fe-Mn-Al-C light steel compared with ordinary heat treatment.

[0134] Comparing the test results of Example 1 and Comparative Example 2, it can be seen that, compared with Example 1, omitting the electron beam remelting treatment of Fe-Mn-Al-C lightweight steel significantly increased the total mass loss and cavitation rate of the sample in Comparative Example 2. Furthermore, Comparative Example 2 did not exhibit a significant incubation period within 0–2.5 hours of the onset of cavitation, showing mass loss in the initial stage at a rapid rate. This indicates that the original density of the Fe-Mn-Al-C lightweight steel was not high, further demonstrating that electron beam remelting plays a crucial role in improving the cavitation resistance of Fe-Mn-Al-C lightweight steel.

[0135] By comparing the test results of Example 1 with those of Comparative Examples 3 and 4, it can be seen that, compared with Example 1, the sample of Comparative Example 2 experienced mass loss after the start of the cavitation erosion experiment, and the rate of mass loss was faster. This indicates that when the process parameters of electron beam remelting are not within the limits of the present invention, even if electron beam remelting is performed, it is impossible to effectively change the surface microstructure of Fe-Mn-Al-C light steel through electron beam remelting. This further demonstrates that the technical effect of the present invention cannot be achieved by arbitrarily performing electron beam remelting. The range of process parameters for electron beam remelting plays an important role in improving the cavitation erosion resistance of Fe-Mn-Al-C light steel.

[0136] In summary, the processing method of the present invention can significantly improve the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel. The key factor in the improvement of the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel by the present invention lies in the control of the process parameters of electron beam remelting. When electron beam remelting is not performed, or when the process parameters of electron beam remelting are lower or higher than the process parameters of the present invention, the improvement of the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel cannot be effectively achieved.

[0137] (II) X-ray diffraction test

[0138] Since the sample materials obtained in Example 2 are similar to those in Example 1, and their cavitation resistance is similar, this invention uses the sample obtained in Example 1 as an example, and the Fe-Mn-Al-C light steel obtained in Comparative Example 1 and the untreated Fe-Mn-Al-C light steel in Comparative Example 5 as controls. X-ray diffraction tests were performed on both, and the test results are as follows: Figure 1 As shown.

[0139] And by Figure 1It can be seen that, compared with the original untreated Fe-Mn-Al-C light steel of Comparative Example 5, only γ-Fe appears in both the Fe-Mn-Al-C light steel sample after electron beam remelting in Example 1 and the Fe-Mn-Al-C light steel sample after heat treatment in Comparative Example 1. This indicates that the Fe-Mn-Al-C light steel does not undergo phase transformation during remelting or heat treatment, and the resulting microstructure is austenitic.

[0140] (III) Surface morphology of alloy after cavitation erosion

[0141] Since the sample materials obtained in Example 2 are similar to those in Example 1, and their cavitation resistance is similar, this invention uses the cavitation-corrosion ... Figure 2-6 As shown.

[0142] Figure 2 The SEM image of the sample from Example 1 after cavitation shows that, after electron beam remelting, the cladding layer formed on the sample surface is not a flat plane, but rather a wavy plane. This indicates that cavitation erosion occurs in the gaps between the cladding layers. The corrosion of the cladding layer progresses gradually from the edges inwards. Therefore, the cladding layer reduces direct corrosion of the Fe-Mn-Al-C light steel, thereby improving its cavitation erosion resistance.

[0143] Figure 3 The SEM image of the sample after cavitation in Comparative Example 1 shows that the cavitation mechanism of the sample after heat treatment is that plastic deformation begins at the austenite grain boundaries, resulting in grain boundary spalling. This indicates that the heat-treated sample still cannot effectively improve the cavitation resistance of Fe-Mn-Al-C light steel.

[0144] Figure 4 The SEM image of Comparative Example 2 after cavitation erosion shows that, compared with Example 1, cavitation erosion occurred at the austenite grain boundaries in Comparative Example 2. This indicates that the Fe-Mn-Al-C light steel sample of Comparative Example 2, after omitting electron beam remelting treatment, has low density. This further illustrates that electron beam remelting treatment plays an important role in improving the cavitation erosion resistance of Fe-Mn-Al-C light steel.

[0145] Figure 5 The image shows the SEM image of the sample in Comparative Example 3 after cavitation. Figure 6The image shows the SEM image of the sample in Comparative Example 4 after cavitation erosion. It can be seen that after the cladding layer forms on the surface of the Fe-Mn-Al-C lightweight steel, the surface is not a smooth plane, but rather a corrugated plane. However, compared to Example 1, the corrosion phenomenon in Comparative Examples 3 and 4 is more severe. This indicates that when the process parameters of electron beam remelting are not within the limits of this invention, even if electron beam remelting is performed, it cannot effectively change the grain structure of the Fe-Mn-Al-C lightweight steel surface. This further demonstrates that the technical effects of this invention cannot be achieved simply by arbitrarily performing electron beam remelting. The range of process parameters for electron beam remelting plays a crucial role in improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel.

[0146] (iv) Hardness test

[0147] The present invention also tested the hardness of the Fe-Mn-Al-C lightweight steels obtained in Examples 1-2 and Comparative Examples 1-4, and the test results are as follows. Figure 7 As shown.

[0148] And by Figure 7 It can be seen that the hardness of the Fe-Mn-Al-C light steel obtained in Examples 1 and 2 is significantly greater than that in Comparative Examples 1-4. This indicates that the treatment method of the present invention can effectively improve the hardness of Fe-Mn-Al-C light steel, thereby improving its cavitation resistance.

[0149] Obviously, the above embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for improving the cavitation erosion resistance of Fe-Mn-Al-C lightweight steel, characterized in that, Includes the following steps: Fe-Mn-Al-C light steel is pretreated to remove dust and impurities from its surface, thereby obtaining pretreated Fe-Mn-Al-C light steel. Under vacuum conditions, the surface of the pretreated Fe-Mn-Al-C light steel is subjected to electron beam remelting treatment to form a cladding layer on the surface of the pretreated Fe-Mn-Al-C light steel, thereby improving the cavitation resistance of the Fe-Mn-Al-C light steel. The scanning speed of the electron beam remelting process is 1.000~5.000m / s, the current intensity is 1.0~20.0mA, and the defocusing amount is -0.100~-0.500V.

2. The method for improving the cavitation resistance of Fe-Mn-Al-C lightweight steel as described in claim 1, characterized in that, The thickness of the cladding layer is 70~150μm.

3. The method as described in claim 1, characterized in that, The scanning speed of the electron beam remelting process is 2.000~3.000m / s, the current intensity is 5.0~15.0mA, and the defocusing amount is -0.200~-0.500V.

4. The method for improving the cavitation resistance of Fe-Mn-Al-C lightweight steel as described in claim 3, characterized in that, The scanning speed of the electron beam remelting process is 2.600 m / s, the current intensity is 10.0~12.0 mA, and the defocusing amount is -0.250~-0.500 V.

5. The method for improving the cavitation resistance of Fe-Mn-Al-C lightweight steel as described in claim 1, characterized in that, The Fe-Mn-Al-C light steel in the cladding layer has equiaxed and columnar crystal structures.

6. The method for improving the cavitation resistance of Fe-Mn-Al-C lightweight steel as described in claim 1, characterized in that, The vacuum level during the electron beam remelting process is 10. -2 ~10 -4 Pa.

7. The method for improving the cavitation resistance of Fe-Mn-Al-C lightweight steel as described in claim 1, characterized in that, The preprocessing includes the following steps: The surface of the Fe-Mn-Al-C lightweight steel was successively ground and polished; then the polished Fe-Mn-Al-C lightweight steel was immersed in ethanol for ultrasonic treatment and then dried.

8. The method for improving the cavitation resistance of Fe-Mn-Al-C lightweight steel as described in claim 7, characterized in that, The polishing process involves using sandpaper to polish the surface of the Fe-Mn-Al-C lightweight steel until the surface roughness of the Fe-Mn-Al-C lightweight steel is 0.1~0.05.

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