Preparation method of 304 stainless steel composite plate

Abstract

The application relates to the field of alloy composite plates, in particular to a preparation method of a 304 stainless steel composite plate. The preparation method of the 304 stainless steel composite plate comprises the following steps: mixing high-entropy alloy powder and water glass, pressing to obtain a metal-based welding agent sheet; attaching the metal-based welding agent sheet to a 304 stainless steel base plate, and performing surfacing to obtain a 304 stainless steel plate with a high-entropy alloy surfacing layer; and performing a thermal process rolling on the 304 stainless steel plate with the high-entropy alloy surfacing layer to obtain the 304 stainless steel composite plate. The surface of the 304 stainless steel composite plate provided by the application is a high-entropy alloy, the high-entropy alloy has good processability, the hardness, wear resistance and tensile strength of the composite plate can be improved through subsequent surfacing and rolling processes, the material utilization rate can be higher and the comprehensive service performance can be better under the condition of meeting the structural performance requirements.

Description

Technical Field

[0001] This invention relates to the field of alloy composite plates, and more particularly to a method for preparing a 304 stainless steel composite plate. Background Technology

[0002] 304 stainless steel is widely used in the manufacture of various load-bearing structural components due to its excellent mechanical properties and good corrosion resistance. However, its shortcomings in strength and wear resistance limit its further application in high-stress and high-wear environments. Therefore, a high-performance composite reinforcing material is needed to enhance the wear resistance of 304 stainless steel. Summary of the Invention

[0003] This invention provides a method for preparing a 304 stainless steel composite plate, which has excellent wear resistance.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides a method for preparing 304 stainless steel composite plates, characterized by comprising the following steps: High-entropy alloy powder and water glass are mixed and pressed to obtain metal-based flux flakes; Metal-based flux sheets are attached to a 304 stainless steel substrate and welded to obtain a 304 stainless steel sheet with a high-entropy alloy weld overlay layer. The 304 stainless steel sheet with the high-entropy alloy overlay is hot-rolled to obtain a 304 stainless steel composite sheet.

[0005] In some specific embodiments, the mass ratio of the high-entropy alloy powder to the water glass is 3~5:1.

[0006] In some specific embodiments, the high-entropy alloy powder comprises Fe, Co, Cr, Ni, and Mn.

[0007] In some specific embodiments, the molar ratio of Fe, Co, Cr, Ni and Mn is 1:(1~2):(1~2):(1~2):(1~2).

[0008] In some specific embodiments, the particle size of the high-entropy alloy powder is 45~105μm.

[0009] In some specific embodiments, the modulus of the water glass is 2.6.

[0010] In some specific embodiments, the metal-based flux sheet has dimensions of 12mm × 10mm × 2mm.

[0011] In some specific embodiments, the welding conditions are as follows: the protective atmosphere is an inert gas, the current is 160~240A, the speed is 1.3~3mm / s, the protective atmosphere flow rate is 12~15L / min, the electrode is a tungsten electrode, and the tungsten electrode diameter is 3.2mm.

[0012] In some specific embodiments, the conditions for the hot rolling process are: temperature of 550~600℃, time of 30~40min, total reduction of 50%~80%, number of passes ≥2, and single reduction of 30%~60%.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The preparation method of the 304 stainless steel composite plate provided by this invention mainly includes: firstly, mixing high-entropy alloy powder and water glass and pressing them to obtain a metal-based flux sheet; then, attaching the metal-based flux sheet to a 304 stainless steel substrate and sequentially performing welding and hot rolling processes to tightly bond the high-entropy alloy and 304 stainless steel, thereby achieving a good bond in the composite plate. The surface of the composite plate is a high-entropy alloy, which has good machinability. Subsequent welding and rolling processes can improve the material's hardness, wear resistance, and tensile strength, resulting in excellent performance. Its strength and wear resistance are higher than those of the 304 stainless steel substrate. Compared to traditional 304 stainless steel plates, the 304 stainless steel composite plate of this invention can achieve higher material utilization and better overall service performance while meeting structural performance requirements. Attached Figure Description

[0014] The above and other objects, features, and advantages of the invention will be apparent from the following description of preferred embodiments illustrating the gist of the invention and its use, and the accompanying drawings, in which: Figure 1 The image shown is a scanning electron microscope (SEM) image of the high-entropy alloy powder in Example 1.

[0015] Figure 2 The image shown is a macroscopic morphology diagram of the metal-based flux sheet in Example 1.

[0016] Figure 3 The image shown is a morphological diagram of the 304 stainless steel sheet with a high-entropy alloy overlay layer in Example 1. Figure 3 (a) shows the side with the high-entropy alloy weld overlay. Figure 3 (b) shows the side without the high-entropy alloy overlay.

[0017] Figure 4 The figure shows the stress-strain curve and tensile strength of the high-entropy alloy weld overlay in the 304 stainless steel sheet with the high-entropy alloy weld overlay in Example 1.

[0018] Figure 5The figure shows the hardness of the high-entropy alloy weld overlay in the 304 stainless steel sheet with the high-entropy alloy weld overlay in Example 1.

[0019] Figure 6 The image shown is a macroscopic morphology of the 304 stainless steel sheet with a high-entropy alloy overlay layer after the first hot rolling process in Example 1.

[0020] Figure 7 The stress-strain curve and tensile strength of the cladding layer in the 304 stainless steel composite plate in Example 1 are shown.

[0021] Figure 8 The figure shows the hardness of the cladding layer in the 304 stainless steel composite plate in Example 1.

[0022] Figure 9 The image shown is a morphological diagram of the 304 stainless steel sheet with a high-entropy alloy overlay layer in Example 2. Figure 9 (a) shows the side with the high-entropy alloy weld overlay. Figure 9 (b) shows the side without the high-entropy alloy overlay.

[0023] Figure 10 The figure shows the stress-strain curve and tensile strength of the high-entropy alloy weld overlay in the 304 stainless steel sheet with the high-entropy alloy weld overlay in Example 2.

[0024] Figure 11 The figure shows the hardness of the high-entropy alloy weld overlay in the 304 stainless steel sheet with the high-entropy alloy weld overlay in Example 2.

[0025] Figure 12 The image shown is a macroscopic morphology diagram of the 304 stainless steel sheet with a high-entropy alloy overlay layer after the first hot rolling process in Example 2.

[0026] Figure 13 The stress-strain curve and tensile strength of the cladding layer in the 304 stainless steel composite plate in Example 2 are shown.

[0027] Figure 14 The figure shows the hardness of the cladding layer in the 304 stainless steel composite plate in Example 2.

[0028] Figure 15 The image shown is a morphological diagram of a 304 stainless steel sheet with a high-entropy alloy weld overlay in Example 3; where (a) is the side with the high-entropy alloy weld overlay and (b) is the side without the high-entropy alloy weld overlay.

[0029] Figure 16 The figure shows the stress-strain curve and tensile strength of the high-entropy alloy weld overlay in the 304 stainless steel sheet with the high-entropy alloy weld overlay in Example 3.

[0030] Figure 17 The figure shows the hardness of the high-entropy alloy weld overlay in the 304 stainless steel sheet with the high-entropy alloy weld overlay in Example 3.

[0031] Figure 18 The image shown is a macroscopic morphology of the 304 stainless steel sheet with a high-entropy alloy overlay layer after the first hot rolling process in Example 3.

[0032] Figure 19 The stress-strain curve and tensile strength of the cladding layer in the 304 stainless steel composite plate in Example 3 are shown.

[0033] Figure 20 The figure shows the hardness of the cladding layer in the 304 stainless steel composite plate in Example 3.

[0034] Figure 21 The figures shown are the three-dimensional morphologies of the worn surfaces of the 304 stainless steel sheet, the 304 stainless steel sheet with a high-entropy alloy weld overlay, the 304 stainless steel sheet with a high-entropy alloy weld overlay after the first hot rolling process, and the 304 stainless steel composite sheet in Example 3; wherein, Figure 21 In the above, (a) is a 304 stainless steel plate, (b) is a 304 stainless steel plate with a high-entropy alloy overlay, (c) is a 304 stainless steel plate with a high-entropy alloy overlay after the first hot rolling process, and (d) is a 304 stainless steel composite plate.

[0035] Figure 22 The figures shown are the friction coefficient variation curves of the 304 stainless steel sheet, the 304 stainless steel sheet with a high-entropy alloy weld overlay, the 304 stainless steel sheet with a high-entropy alloy weld overlay after the first hot rolling process, and the 304 stainless steel composite sheet in Example 3.

[0036] Figure 23 The following are the EDS elemental distribution results of the 304 stainless steel composite plate in Example 3, where (a) is a low-magnification morphology image, (b) is a high-magnification morphology image, (c) is the EDS image of Mn, (d) is the EDS image of Cr, (e) is the EDS image of Fe, (f) is the EDS image of Ni, and (g) is the EDS image of Co.

[0037] Figure 24 The figure shows the IPF and grain size distribution of the 304 stainless steel composite plate in Example 3, where (a) is the IPF and (b) is the grain size distribution. Detailed Implementation

[0038] The present invention will be described below through specific embodiments. Those skilled in the art will understand that the specific embodiments described below are for illustrative purposes only and do not limit the scope of the invention in any way. Furthermore, in the following embodiments, unless otherwise specified, the reagents and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the following embodiments, conditions and methods known in the art can be used for processing.

[0039] This invention provides a method for preparing 304 stainless steel composite plates, comprising the following steps: High-entropy alloy powder and water glass are mixed and pressed to obtain metal-based flux flakes; Metal-based flux sheets are attached to a 304 stainless steel substrate and welded to obtain a 304 stainless steel sheet with a high-entropy alloy weld overlay layer. The 304 stainless steel sheet with the high-entropy alloy overlay is hot-rolled to obtain a 304 stainless steel composite sheet.

[0040] In some embodiments, the mass ratio of the high-entropy alloy powder to the water glass is 3 to 5:1. As examples, the mass ratio of the high-entropy alloy powder to the water glass can be 3:1, 3.5:1, 4:1, 4.5:1, and 5:1, etc.

[0041] In this invention, high-entropy alloy powder and water glass are mixed, with the water glass acting as a binder to facilitate the subsequent pressing and forming of the high-entropy alloy powder. Furthermore, the water glass is discharged as weld slag during the subsequent welding process, having no impact on the weld performance.

[0042] In some embodiments, the high-entropy alloy powder comprises Fe, Co, Cr, Ni, and Mn.

[0043] In some embodiments, the molar ratio of Fe, Co, Cr, Ni and Mn is 1:(1~2):(1~2):(1~2):(1~2), preferably 1:1:1:1:1.

[0044] In this invention, the high-entropy alloy FeCrNiCoMn is an important system for transitioning from high-entropy alloys to engineering applications. Ni and Co both belong to the fourth period and are both group VIII elements. Their atomic radii and properties are very similar, and they can easily form stable solid solutions with other metals. It has stable FCC solid solutions, low stacking fault energy, and the potential to activate multiple slip systems.

[0045] In some embodiments, the particle size of the high-entropy alloy powder is 45~105 μm. As an example, the particle size of the high-entropy alloy powder can be 45 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, and 105 μm, etc.

[0046] In some embodiments, the modulus of the water glass is 2.6.

[0047] In some embodiments, after mixing the high-entropy alloy powder and water glass, the process further includes: drying and sieving.

[0048] In this invention, water glass is a liquid. After mixing high-entropy alloy powder and binder water glass, the resulting high-entropy alloy powder is flocculent. After drying, it can be broken into powder. Sieving is done to turn the flocculent powder into fine particles.

[0049] In some embodiments, the pressing process further includes drying. In this invention, drying facilitates the storage and use of the metal-based flux sheet.

[0050] In this invention, there are no special limitations on the pressing conditions; the mixture of high-entropy alloy powder and water glass can be pressed into shape.

[0051] In some embodiments, the metal-based flux sheet has dimensions of 12mm × 10mm × 2mm.

[0052] In this invention, metal-based flux sheets are attached to a 304 stainless steel substrate. The small and regular structure of the flux sheets has a natural modularity, which is suitable for rapid manufacturing and automated assembly, and facilitates precise laying or configuration in complex geometric structures or specific functional areas.

[0053] In some embodiments, the welding conditions are as follows: the protective atmosphere is an inert gas, the current is 160~240A, the velocity is 1.3~3mm / s, the protective atmosphere flow rate is 12~15L / min, the electrode is a tungsten electrode with a diameter of 3.2mm. As an example, the current can be 160A, 180A, 200A, 220A, and 240A, etc.; the velocity can be 1.3mm / s, 1.5mm / s, 2mm / s, 2.5mm / s, and 3mm / s, etc.; and the protective atmosphere flow rate can be 12L / min, 12.5L / min, 13L / min, 13.5L / min, 14L / min, 14.5L / min, and 15L / min, etc. In this invention, the inert atmosphere during the welding process can be nitrogen, argon, helium, etc.

[0054] In some embodiments, the hot rolling conditions are as follows: temperature 550~600℃, time 30~40min, total reduction 50%~80%, number of passes ≥2, and single reduction 30%~60%. As examples, the temperature can be 550℃, 560℃, 570℃, 580℃, and 600℃, the time can be 30min, 32min, 35min, 38min, and 40min, the total reduction can be 50%, 55%, 60%, 65%, 70%, 75%, and 80%, the number of passes can be 2, 3, and 4, and the single reduction can be 30%, 35%, 40%, 45%, 50%, 55%, and 60%.

[0055] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. The embodiments of this application are only examples, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Example 1 High-entropy alloy powder (particle size 45~105μm, purity >99.95%) composed of Fe, Co, Cr, Ni and Mn in equimolar ratio and water glass (modulus 2.6) were mixed at a mass ratio of 3.5:1. After drying, passing through a 100-mesh sieve, pressing and drying, metal-based flux sheets with dimensions of 12mm×10mm×2mm were obtained. Metal-based flux sheets were attached to a 304 stainless steel substrate for overlay welding. 99% pure argon was used as the shielding gas during the overlay welding process. Self-fusion was carried out without wire feeding. The overlay welding was performed using DC positive polarity, with a welding current of 160A, a welding speed of 1.5mm / s, a shielding gas flow rate of 15L / min, and a tungsten electrode diameter of 3.2mm, resulting in a 304 stainless steel sheet with a high-entropy alloy overlay layer. Hot rolling of 304 stainless steel sheet with high-entropy alloy weld overlay was carried out in two passes. In the first pass, the 304 stainless steel sheet with high-entropy alloy weld overlay was heated to 600℃ and held for 30 minutes before pre-pressing, from 10mm to 7.5mm. At this time, the weld excess height was flattened. The sheet was immediately placed in a furnace to reheat to 600℃, held for 5 minutes again, and then rolled for the first pass, from 7.5mm to 5mm. The sheet was then reheated to 600℃, held for 5 minutes again, and then rolled for the second pass, from 5mm to 2mm. No cracking occurred in the material during the rolling process. The high-entropy alloy weld overlay formed a cladding layer, resulting in a 304 stainless steel composite sheet.

[0057] Figure 1 The image shown is a scanning electron microscope (SEM) image of the high-entropy alloy powder from Example 1. Figure 1It is known that the material used for arc welding is a commercially available high-purity high-entropy alloy powder with a particle size of 45-105μm and a purity greater than 99.95%.

[0058] Figure 2 The image shown is a macroscopic morphology diagram of the metal-based flux sheet in Example 1. (The image is derived from...) Figure 2 It can be seen that the flux sheet has a uniform thickness, a complete sheet shape, a smooth surface with a metallic luster, and no burrs, indicating that it is of qualified quality.

[0059] Figure 3 The image shown is a morphological diagram of the 304 stainless steel sheet with a high-entropy alloy overlay layer in Example 1. Figure 3 (a) shows the side with the high-entropy alloy weld overlay. Figure 3 (b) shows the side without the high-entropy alloy weld overlay. Figure 3 As can be seen, the weld bead is smooth and flat, with a fish-scale pattern, and the edges are flat with a moderate excess height, resulting in a good surface finish. The 304 stainless steel surface on the back shows slight oxidation after heating, but this does not affect the joint quality.

[0060] Tensile tests were conducted on the high-entropy alloy weld overlay in the 304 stainless steel sheet with the high-entropy alloy weld overlay in Example 1 according to the national standard GB / T228.1-2010. The stress-strain curves are as follows: Figure 4 As shown. By Figure 4 It can be seen that the overall tensile curve of the joint shows high yield strength and tensile strength, but lower than the properties of the base material.

[0061] The hardness of the high-entropy alloy weld overlay in the 304 stainless steel sheet with the high-entropy alloy weld overlay in Example 1 was tested. Specifically, Vickers microhardness testing was used. To investigate the hardness variation under different process changes, microhardness analysis was performed on the metallographic sample. Vickers hardness was used as the hardness test standard. A Wilson VH1102 microhardness tester was used to measure the hardness at room temperature. An array method was used, with a loading load of 5 kgf, a loading time of 15 s, and a spacing of 0.2 mm between adjacent points. The results are as follows. Figure 5 As shown, Figure 5 CZ is the solder overlay, HAZ is the heat-affected zone, and BM is the 304 stainless steel substrate. Figure 5 It can be seen that the overall hardness increases from the weld overlay to the base metal, meaning the hardness of the weld zone (CZ) is lower than that of the bonding zone (BZ), lower than that of the heat-affected zone (HAZ), and lower than that of the base metal (BM). The average hardness of the weld overlay is 155 HV, while the average hardness of the base metal is 180 HV, indicating a low-strength matching joint.

[0062] Figure 6This is a macroscopic morphology image of the 304 stainless steel sheet with a high-entropy alloy weld overlay in Example 1 after the first hot rolling process, where RD represents the rolling direction. Figure 6 It can be seen that the weld excess height on the weld overlay side is completely eliminated, and the rolled surface is smooth and flat.

[0063] Tensile tests were conducted on the cladding layer of the 304 stainless steel composite plate in Example 1 according to the national standard GB / T228.1-2010, and its stress-strain curve is shown below. Figure 7 As shown. By Figure 7 It can be seen that after rolling, the tensile strength of the weld overlay material can reach 850 MPa, and the elongation can reach 25%~30%. The overall mechanical properties have exceeded those of the original base material.

[0064] The hardness of the cladding layer in the 304 stainless steel composite plate in Example 1 was tested, and the results are as follows: Figure 8 As shown, Figure 8 CZ is the cladding layer, HAZ is the heat-affected zone, and BM is the 304 stainless steel substrate. Figure 8 It can be seen that the hardness of the cladding layer is higher than that of the substrate, indicating that the rolling process has a significant work hardening effect on the high-entropy alloy layer.

[0065] Example 2 The same metal-based flux sheet as in Example 1 was attached to a 304 stainless steel substrate for overlay welding. During the overlay welding process, 99% pure argon gas was used as the shielding gas, and self-melting was carried out without wire feeding. The overlay welding was performed using DC positive polarity, with an overlay welding current of 220A, an overlay welding speed of 1.5mm / s, a shielding gas flow rate of 15L / min, and a tungsten electrode diameter of 3.2mm, resulting in a 304 stainless steel sheet with a high-entropy alloy overlay layer. Hot rolling of 304 stainless steel sheet with high-entropy alloy weld overlay was carried out in two passes. In the first pass, the 304 stainless steel sheet with high-entropy alloy weld overlay was heated to 600℃ and held for 30 minutes before pre-pressing, from 10mm to 7.5mm. At this time, the weld excess height was flattened. The sheet was immediately placed in a furnace to reheat to 600℃, held for 5 minutes again, and then rolled for the first pass, from 7.5mm to 5mm. The sheet was then reheated to 600℃, held for 5 minutes again, and then rolled for the second pass, from 5mm to 2mm. No cracking occurred in the material during the rolling process. The high-entropy alloy weld overlay formed a cladding layer, resulting in a 304 stainless steel composite sheet.

[0066] Figure 9 The image shown is a morphological diagram of the 304 stainless steel sheet with a high-entropy alloy overlay layer in Example 2. Figure 9 (a) shows the side with the high-entropy alloy weld overlay. Figure 9 (b) shows the side without the high-entropy alloy weld overlay. Figure 9 It can be seen that the weld bead of the overlay layer is well formed and there are no obvious macroscopic defects.

[0067] Tensile tests were conducted on the high-entropy alloy weld overlay in the 304 stainless steel sheet with the high-entropy alloy weld overlay in Example 2 according to the national standard GB / T228.1-2010. The stress-strain curves are as follows: Figure 10 As shown. By Figure 10 It can be seen that the welded joint has a transverse tensile strength of 550MPa and an elongation of more than 50%, indicating a low-matching joint.

[0068] The hardness of the high-entropy alloy weld overlay in the 304 stainless steel sheet with the high-entropy alloy weld overlay in Example 2 was tested. The hardness testing method was the same as in Example 1, and the results are as follows: Figure 11 As shown, Figure 11 CZ is the solder overlay, HAZ is the heat-affected zone, and BM is the 304 stainless steel substrate. Figure 11 It can be seen that the overall joint hardness distribution is: weld < heat-affected zone < base metal, which is still a low-strength matching joint.

[0069] Figure 12 This is a macroscopic morphology image of the 304 stainless steel sheet with a high-entropy alloy weld overlay in Example 2 after the first hot rolling process, where RD represents the rolling direction. Figure 12 It can be seen that the surface of rolled sheet is smooth and flat, without burrs, cracks or flash.

[0070] Tensile tests were conducted on the cladding layer of the 304 stainless steel composite plate in Example 2 according to the national standard GB / T228.1-2010, and its stress-strain curve is shown below. Figure 13 As shown. By Figure 13 It can be seen that after rolling, the tensile strength of the material increases to 850MPa, while the elongation remains at 25%-30%.

[0071] The hardness of the cladding layer in the 304 stainless steel composite plate in Example 2 was tested using the same method as in Example 1. The results are as follows: Figure 14 As shown, Figure 14 CZ is the cladding layer, HAZ is the heat-affected zone, and BM is the 304 stainless steel substrate. Figure 14 It can be seen that the hardness of the weld overlay is significantly higher than that of the base metal, and the overall hardness distribution trend is weld > heat-affected zone > base metal.

[0072] Example 3 The same metal-based flux sheet as in Example 1 was attached to a 304 stainless steel substrate for overlay welding. During the overlay welding process, 99% pure argon was used as the shielding gas, and self-melting was carried out without wire feeding. The overlay welding was performed using DC positive polarity, with an overlay welding current of 240A, an overlay welding speed of 1.5mm / s, a shielding gas flow rate of 15L / min, and a tungsten electrode diameter of 3.2mm, resulting in a 304 stainless steel sheet with a high-entropy alloy overlay welding layer. Hot rolling of 304 stainless steel sheet with high-entropy alloy weld overlay was carried out in two passes. In the first pass, the 304 stainless steel sheet with high-entropy alloy weld overlay was heated to 600℃ and held for 30 minutes, then pre-pressed from 10mm to 7.5mm. At this time, the weld excess height was flattened. The sheet was then immediately placed in a furnace to reheat to 600℃, held for 5 minutes, and then rolled for the first pass from 7.5mm to 5mm. The sheet was then reheated to 600℃ and held for 5 minutes before the second pass rolling from 5mm to 2mm. No cracking occurred in the material during the rolling process. The high-entropy alloy weld overlay formed a cladding layer, resulting in a 304 stainless steel composite sheet.

[0073] Figure 15 The image shown is a morphological diagram of the 304 stainless steel sheet with a high-entropy alloy overlay layer in Example 3. Figure 15 (a) shows the side with the high-entropy alloy weld overlay. Figure 15 (b) shows the side without the high-entropy alloy weld overlay. Figure 15 It can be seen that the weld bead is smooth and flat, with good formation and no obvious macroscopic defects. The weld reinforcement is large and the weld bead is narrow, which is due to the increased cladding rate under large-scale welding conditions.

[0074] Tensile tests were conducted on the high-entropy alloy weld overlay in the 304 stainless steel sheet with the high-entropy alloy weld overlay in Example 3 according to the national standard GB / T228.1-2010. The stress-strain curves are as follows: Figure 16 As shown. By Figure 16 It is known that the tensile strength of 304 stainless steel sheet with high-entropy alloy overlay reaches 550MPa and the elongation is 45%.

[0075] The hardness of the high-entropy alloy weld overlay in the 304 stainless steel sheet with the high-entropy alloy weld overlay in Example 3 was tested. The hardness testing method was the same as in Example 1, and the results were as follows: Figure 17 As shown, Figure 17 CZ is the solder overlay, HAZ is the heat-affected zone, and BM is the 304 stainless steel substrate. Figure 17 It can be seen that the overall hardness distribution is: weld < heat-affected zone < base metal.

[0076] Figure 18This is a macroscopic morphology image of the 304 stainless steel sheet with a high-entropy alloy weld overlay in Example 3 after the first hot rolling process, where RD represents the rolling direction. Figure 18 It can be seen that the weld bead excess disappears, and the surface of the rolled plate is smooth and flat without burrs.

[0077] The cladding layer of the 304 stainless steel composite plate in Example 3 was subjected to a tensile test according to the national standard GB / T228.1-2010, and its stress-strain curve is shown below. Figure 19 As shown. By Figure 19 It can be seen that the tensile strength of the material after rolling reaches 800MPa, and the elongation remains at 25%.

[0078] The hardness of the cladding layer in the 304 stainless steel composite plate in Example 3 was tested using the same method as in Example 1. The results are as follows: Figure 20 As shown, Figure 20 CZ is the cladding layer, HAZ is the heat-affected zone, and BM is the 304 stainless steel substrate. Figure 20 It can be seen that the hardness of the weld overlay material increases to 320HV after rolling, exceeding that of the base material and the heat-affected zone.

[0079] Figure 21 The image shows the three-dimensional morphology of the worn surfaces of 304 stainless steel sheet, 304 stainless steel sheet with a high-entropy alloy weld overlay, 304 stainless steel sheet with a high-entropy alloy weld overlay after the first hot rolling process, and 304 stainless steel composite sheet in Example 3. The specific wear process involved: friction tests on the composite material, using an HT-1000 ball-and-disc high-temperature friction testing machine to detect the friction and wear performance of the test samples. The paired balls used in the friction test were 6mm diameter Si3N4 ceramic balls, and the sample was a 20mm diameter, 2mm thick disc. (a) is a 304 stainless steel sheet, (b) is a 304 stainless steel sheet with a high-entropy alloy weld overlay, (c) is a 304 stainless steel sheet with a high-entropy alloy weld overlay after the first hot rolling process, and (d) is a 304 stainless steel composite sheet. Figure 21 It can be seen that the wear depth of the high-entropy alloy composite layer after rolling with 50% reduction is significantly reduced to 21.5 µm, and shallow furrows appear on the surface with relatively uniform overall wear. This is closely related to the increase in hardness after rolling, indicating that the work hardening effect improves the wear resistance of the composite layer.

[0080] Figure 22 The figures shown are the friction coefficient variation curves of the 304 stainless steel sheet, the 304 stainless steel sheet with a high-entropy alloy weld overlay, the sheet after the first hot rolling process, and the 304 stainless steel composite sheet in Example 3. Figure 22In this context, BM represents 304 stainless steel sheet, surfacing welding indicates 304 stainless steel sheet with a high-entropy alloy weld overlay, Rolling-50% indicates sheet after the first hot rolling process, and Rolling-80% indicates 304 stainless steel composite sheet. Figure 22 As shown in the curve, this is the friction coefficient curve of the composite material as a function of time. The curve reveals that the friction coefficient of the material under different processing conditions exhibits a trend of first increasing rapidly and then gradually stabilizing. This indicates that the material's wear resistance is stable and durable.

[0081] Figure 23 The image shows the EDSEDS elemental distribution results of the 304 stainless steel composite sheet in Example 3, where CZ represents the cladding layer and BM represents the matrix. Figure 23 It is evident that the various elements exhibit different diffusion behaviors in the weld overlay and the matrix region. Enhanced diffusion of Fe at the interface indicates that rolling promotes metallurgical bonding; Cr is uniformly distributed in the weld overlay without significant segregation; Mn, Ni, and Co are mainly distributed in the weld overlay, exhibiting very uniform distribution without severe segregation. Rolling deformation not only improves the interfacial bonding strength, thereby promoting dynamic recovery and local recrystallization, resulting in a more uniform microstructure, but also reduces stress concentration, improving the overall performance of the composite material.

[0082] Figure 24 The image shows the IPF and grain size distribution of the 304 stainless steel composite plate in Example 3, where (a) is the IPF and (b) is the grain size distribution. Figure 24 It can be seen that the grain size distribution is relatively dispersed, and recrystallized grains appear in some areas. Grain statistical analysis shows that the internal structure of the material underwent partial dynamic recovery and dynamic recrystallization in the high strain region, thereby reducing dislocation pile-up and improving the deformation compatibility of the material. This indicates that rolling deformation significantly improves the microstructure of the weld overlay high-entropy alloy, reducing internal stress and refining the grains.

[0083] Although preferred embodiments of the invention have been shown and described, it is conceivable that those skilled in the art can devise various modifications to the invention within the spirit and scope of the appended claims.

Claims

1. A method for preparing a 304 stainless steel composite plate, characterized in that, Includes the following steps: High-entropy alloy powder and water glass are mixed and pressed to obtain metal-based flux flakes; Metal-based flux sheets are attached to a 304 stainless steel substrate and welded to obtain a 304 stainless steel sheet with a high-entropy alloy weld overlay layer. The 304 stainless steel sheet with the high-entropy alloy overlay is hot-rolled to obtain a 304 stainless steel composite sheet.

2. The method for preparing 304 stainless steel composite plate according to claim 1, characterized in that, The mass ratio of the high-entropy alloy powder to the water glass is 3~5:

1.

3. The method for preparing 304 stainless steel composite plate according to claim 1, characterized in that, The high-entropy alloy powder comprises Fe, Co, Cr, Ni, and Mn. The molar ratio of Fe, Co, Cr, Ni and Mn is 1:(1~2):(1~2):(1~2):(1~2); The particle size of the high-entropy alloy powder is 45~105μm.

4. The method for preparing 304 stainless steel composite plate according to claim 1, characterized in that, The modulus of the water glass is 2.

6.

5. The method for preparing 304 stainless steel composite plate according to claim 1, characterized in that, The metal-based flux sheet has dimensions of 12mm × 10mm × 2mm.

6. The method for preparing 304 stainless steel composite plate according to claim 1, characterized in that, The conditions for the welding are as follows: the protective atmosphere is an inert gas, the current is 160~240A, the speed is 1.3~3mm / s, the protective atmosphere flow rate is 12~15L / min, the electrode is a tungsten electrode, and the diameter of the tungsten electrode is 3.2mm.

7. The method for preparing 304 stainless steel composite plate according to claim 1, characterized in that, The conditions for hot rolling are: temperature of 550~600℃, time of 30~40min, total reduction of 50%~80%, number of passes ≥2, and single reduction of 30%~60%.

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