Shaft sleeve cladding layer for hot-dip high-aluminum zinc wire zinc pot roller shaft head and preparation method of shaft sleeve cladding layer

Abstract

The invention discloses a shaft sleeve cladding layer for a hot-dip high-aluminum zinc wire zinc pot roller shaft head and a preparation method. The shaft sleeve cladding layer comprises the following components in percentage by mass: 30-50% of cast tungsten carbide, 1-3% of La2O3 powder and the balance of cobalt-based alloy powder, the cobalt-based alloy powder comprises, by mass, 1%-3% of C, 5.0%-10% of W, 25.0%-30.0% of Cr, smaller than or equal to 2.0% of Si, smaller than or equal to 2.0% of Fe, 1.5%-2.0% of Mo and the balance Co and inevitable impurities. The shaft sleeve cladding layer for the hot-dip high-aluminum-zinc wire zinc pot roller shaft head, which is uniform in structure and has good corrosion resistance, wear resistance and 600 DEG C high temperature resistance in a high-aluminum-zinc metal bath, can be obtained, and the problem that a hot-dip high-aluminum-zinc unit zinc pot roller system bearing is short in service life is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of bushings for hot-dip coating equipment shafts in the cold rolling process, and more specifically, to a cladding layer for a bushing used at the shaft head of a zinc pot roller in a hot-dip high-aluminum zinc wire and a preparation method therefor. Background Art

[0002] The hot-dip high-aluminum zinc production line is used to continuously produce strip steel with a hot-dip aluminum-zinc coating. The hot-dip process is completed in a zinc pot, which is specifically divided into a hot-dip aluminum-zinc production line and a hot-dip high-aluminum zinc-aluminum-magnesium production line. Among them, the metal bath composition used in the zinc pot of the hot-dip aluminum-zinc production line is 55% Al + 1.6% Si + the rest is Zn; the metal bath composition used in the hot-dip high-aluminum zinc-aluminum-magnesium production line is 55% Al + 1.6% Si + 2% Mg + the rest is Zn; in the above-mentioned hot-dip high-aluminum zinc production line, the temperature of the molten metal is 590 - 600°C.

[0003] Combined with Figure 1 As shown in the hot-dip high-aluminum zinc production line, the strip steel 100 enters the zinc pot obliquely. After the strip steel 100 is turned by the sink roll 3, it goes vertically upward and passes through two positioning rolls, usually called the front and rear stabilizing rolls 1 and 2, and then leaves the surface of the zinc bath; the strip steel 100 realizes the so-called "hot-dip" in the zinc bath and forms a corresponding zinc coating. Obviously, the three rolls in the zinc bath, including the sink roll 3, the front stabilizing roll 1, and the rear stabilizing roll 2, are rotating mechanical equipment that is integrally immersed in the high-temperature molten metal. Sliding bearings, which are also commonly referred to as "bushing bearings" in the industry, are required on both sides of each of the three rolls to achieve support. Figure 2 This is a schematic diagram of the bushing bearings of the zinc pot rolls in the hot-dip high-aluminum zinc production line. Among them, the bushing 4 refers to the component installed at the shaft head of the roll system and rotates with the roll system during use. The bearing 5 refers to the component that matches the bushing to form a friction pair and does not rotate itself.

[0004] During continuous hot-dip high-aluminum zinc production of strip steel, the composition and temperature of the metal bath have an important impact on the continuous hot-dip process of strip steel. Generally, elements such as zinc, aluminum, magnesium, and silicon in the zinc liquid will accelerate the corrosion rate of the strip steel and iron facilities in the zinc pot under the melting condition of 590 - 600°C. Therefore, for the friction pair materials such as the bushing bearings of the zinc pot rolls in the hot-dip high-aluminum zinc production line, first of all, the bushing bearings should have excellent corrosion resistance; secondly, the bushing bearings should have excellent wear resistance. The moving speed of the strip steel is as high as 3 - 4 m / s, and the force is 3 - 6 tons at the same time, or the tensile stress is (1 / 10 - 1 / 3) of the yield limit of the strip steel. The bushing bearings are used as support components; thirdly, the bushing bearings should also have excellent high-temperature resistance, that is, at 600°C, the material still has good mechanical properties, etc. At present, the bearing life of the zinc pot roll system in the hot-dip high-aluminum zinc production line is generally relatively short, about 7 - 14 days. Therefore, there is an urgent need in the industry to develop bushing materials with high-temperature resistance of 600°C, corrosion resistance to aluminum-zinc liquid, and wear resistance.

[0005] At present, there are mainly two paths for the preparation of hot-dip high-aluminum zinc bushings at home and abroad: integral casting and additive manufacturing modification from the surface of the base material.

[0006] Integral casting means that after the cobalt-based alloy is melted as a whole, it is cast into shape through a mold; the bushings obtained by this technology are homogeneous phases, and the wear resistance mainly depends on the phase structure of the material, and the wear resistance is insufficient in principle.

[0007] There are mainly two technical paths for additive manufacturing modification from the surface of the base material: surface thermal spraying and plasma cladding. Thermal spraying technology (Hot Spray, HS) is a surface strengthening technology and an important part of surface engineering technology. It uses a certain heat source (such as electric arc, plasma spraying or combustion flame, etc.) to heat powdery or filamentous metal or non-metal materials to a molten or semi-molten state, and then jets them onto the pre-treated substrate surface at a certain speed by means of the flame itself or compressed air to deposit and form a surface coating with various functions. Plasma cladding technology (Plasma Transferred Arc, PTA) is a surface modification technology that uses ions and electrons in a high-temperature plasma state to melt the sprayed material, so that the sprayed material fuses with the substrate surface. The above two technical paths can modify the surface of the substrate, improve wear resistance, corrosion resistance and high-temperature resistance, and can be applied in various mechanical equipment, aerospace and energy and other fields; the difference is that the working conditions are different and the applicable scenarios are different; among them, the bonding layer of thermal spraying is generally mechanical bonding, while plasma cladding is metallurgical bonding. The thermal spray coating is a brittle material and is generally thin, while plasma cladding can obtain a thicker coating. In the above additive manufacturing, the component design and manufacturing process of its surface modification layer should match each other.

[0008] The existing thermal spraying technologies are as follows: Chinese Patent CN200710030081.X discloses the chemical composition of a bushing for a nickel-based zinc pot roller: C: 0.03 - 0.8%, Cr: 4.0 - 16%, Si: 3.2 - 4.0%, W: 0 - 3.0%, Fe: 1.2 - 15%, Mo: 0 - 33.0%, B: 0 - 3.5%, and the rest is Ni; this zinc corrosion resistance is achieved by oxy-fuel spray welding, plasma spray welding or laser cladding methods, which are sprayed or clad on the surface of the bushing to make its surface have high hardness and high mechanical strength and can withstand the erosion of high-temperature zinc; this nickel-based system of components is applicable to a 460°C zinc bath, but in a high-aluminum zinc working condition of 600°C, the nickel-based powder will decompose and is not applicable. US Patent US5116431 discloses a method for preparing a Co-Cr-Ni-W-Fe-Si-B-based alloy protective layer on the surface of parts in a zinc pot by spraying and then roasting. Although the metal-based coating has good toughness and good fusion with the substrate, its hardness is relatively low and its service life is short. Chinese Patent CN201910506905.9 discloses a thermal spraying method for a mixed material of nickel-chromium-boron-silicon alloy powder and cast tungsten carbide powder, which can effectively improve the wear resistance of a pure metal base. However, due to the relatively high powder density of cast tungsten carbide, it is easy to cause composition segregation during the thermal spraying process. At the same time, due to the poor fusion of tungsten carbide with the substrate, when the coating thickness is increased, cracks are easily generated, resulting in a low coating thickness and reducing the service life of the bushing.

[0009] The existing plasma cladding technologies are as follows: Chinese Patent CN 200910018107.8 discloses an alloy powder for plasma cladding, which mainly includes 41-50% Cr, 6-25% Ti, and B, Si, C, Ni, etc. The content is extremely low, and the powder does not contain Co and W. Essentially, it is a reactive plasma cladding technology, where C and Ti react in the molten pool to form TiC. Chinese Patent CN200810102251.5 discloses a preparation method of a (FeAl+Cr7C3) / γ-Fe,Ni) composite coating. Based on iron-based powder, the wear resistance of the plasma cladding layer is improved by adding 10-15% by mass of alumina powder, and its wear-resistant layer is an iron-based + alumina system. Chinese Patent CN201310310128.3 discloses a plasma cladding gradient wear-resistant layer and its preparation process. It uses plasma cladding and adds hard phases to the iron-based powder. The so-called gradient coating refers to being divided into two layers, and the hard phases are both Cr3C2, with the difference being their respective contents. Among them, the bottom layer is 30-40%, and the outer layer is 40-50%. Its wear-resistant layer is an iron-based + Cr3C2 system. Chinese Patent CN201510305784.3 discloses a preparation method of a Ni-(Ta / Zr / Hf)-Re alloy powder for plasma cladding. The protected point of this patent is in powder preparation and does not involve the component design and processing technology of plasma cladding. Chinese Patent CN201610796406.4 discloses a method for obtaining a metallurgical coating by plasma high-speed spray cladding. Its main technical feature is that the powder is a mixture sintering of Al, Cr2O3, Ti, C, etc., and the mass percentages of the four are 10:3:2:9. Chinese Patent CN201810472894.2 discloses a preparation method of a nickel-chromium-boron-silicon and titanium nitride wear-resistant coating. The powder for plasma cladding is nickel-chromium-boron-silicon and titanium nitride, where the former accounts for 75-85%, and the remainder is the latter. The wear-resistant layer is obtained by plasma cladding, and its wear-resistant layer is a nickel + titanium nitride system. The above-mentioned plasma cladding technologies mainly focus on the materials of the cladding layer under different working conditions. However, for the application in high-aluminum-zinc working conditions, there are no reports, and there is also a lack of component design suitable for high-aluminum-zinc working conditions.

[0010] In view of the above situation, it is urgent to develop a shaft sleeve cladding layer for the head of the zinc pot roller of a hot-dip high-aluminum-zinc wire that can withstand high temperatures of 600°C, corrosion by aluminum-zinc liquid, and wear, and a preparation method thereof, so as to solve the problem of the short service life of the bearings in the zinc pot roller system of the hot-dip high-aluminum-zinc unit in the prior art. Summary of the Invention

[0011] Aiming at the defects existing in the prior art, the purpose of the present invention is to provide a cladding layer for the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire and a preparation method thereof. By designing the components of the wear-resistant layer, using cobalt-based mixed powder as the binder phase and tungsten carbide as the hard phase, and adopting the plasma cladding technology, a cladding layer for the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire with uniform structure, good corrosion resistance, wear resistance and high temperature resistance of 600 °C in a high-aluminum zinc metal bath is obtained, solving the problem of the short service life of the bearings of the zinc pot roller system in a hot-dip high-aluminum zinc unit.

[0012] To achieve the above object, the present invention adopts the following technical solutions:

[0013] The first aspect of the present invention provides a cladding layer for the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire, including the following components by mass percentage: cast tungsten carbide: 30-50%, La2O3 powder: 1-3%, and the rest is cobalt-based alloy powder;

[0014] The cobalt-based alloy powder includes the following components by mass percentage: C: 1-3%, W: 5.0-10%, Cr: 25.0-30.0%, Si≤2.0%, Fe≤2.0%, Mo: 1.5-2.0%, and the balance is Co and inevitable impurities.

[0015] Preferably, in the cobalt-based alloy powder, the Si content is 1.0-2.0%, and the Fe content is 1.0-2.0%.

[0016] Preferably, the Leeb hardness HL of the cladding layer for the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire is ≥700, and the Rockwell hardness HRC is ≥50.

[0017] The second aspect of the present invention provides a preparation method for the cladding layer of the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire, including the following steps:

[0018] S1, the metal shaft sleeve substrate is subjected to surface pretreatment to remove the surface oxide layer;

[0019] S2, the cobalt-based alloy powder, cast tungsten carbide powder and La2O3 powder are configured according to the components of the cladding layer for the shaft sleeve of the zinc pot roller shaft head of the hot-dip high-aluminum zinc wire described in the first aspect of the present invention, and after being fully mixed, they are vacuum dried to obtain the cladding powder;

[0020] S3, the cladding powder obtained in step S2 is subjected to plasma cladding in a synchronous powder feeding manner under the protection of an inert gas to form a plasma cladding layer on the surface of the metal shaft sleeve substrate;

[0021] S4, the metal shaft sleeve with a plasma cladding layer on its surface is naturally cooled in a holding furnace.

[0022] Preferably, in the step S2, the particle sizes of the cobalt-based alloy powder and the cast tungsten carbide powder are 40 - 150 μm, and the particle size of the La2O3 powder is 1 - 10 μm.

[0023] Preferably, in the step S2, the cobalt-based alloy powder, the cast tungsten carbide powder, and the La2O3 powder are mixed in a double-cone mixer, and the mixing time is 12 - 48 h.

[0024] Preferably, in the step S2, the drying temperature of the vacuum drying is 100 - 200 °C, and the drying time is 3 - 10 h.

[0025] Preferably, in the step S3:

[0026] During the plasma cladding process, the working current is 300 - 400 A, the scanning speed is 80 - 200 mm / min, the distance between the nozzle and the metal bushing substrate is 10 - 50 mm, the overlapping rate is 40 - 60%, and the powder feeding rate is 30 - 100 g / min; and / or

[0027] The inert gas is Ar, the flow rate of the protective gas is 0.5 - 1.0 m 3 / h, the flow rate of the powder feeding gas is 0.5 - 1.0 m 3 / h, and the flow rate of the plasma gas is 0.5 - 1.0 m 3 / h.

[0028] Preferably, in the step S3, during the plasma cladding process, the number of plasma cladding passes is 1 - 2 passes, and the cladding thickness of a single pass is 2.0 - 3.0 mm.

[0029] Preferably, in the step S4, the natural cooling time of the metal bushing with the cladding layer in a closed heat preservation furnace is 36 - 48 h.

[0030] Advantages of the present invention:

[0031] 1. For the cladding layer and the preparation method of the bushing for the zinc pot roller shaft head of the hot-dip high-aluminum zinc wire provided by the present invention, through the component design of the wear-resistant layer of the bushing, using the cobalt-based alloy powder and the La2O3 powder as the bonding phase, using tungsten carbide as the hard phase, and processing by using the plasma cladding technology, while improving the overall hardness of the wear-resistant layer, the wear resistance is greatly increased;

[0032] 2. The present invention prepares a cladding layer for the shaft sleeve at the shaft head of the zinc pot roller for hot-dip high-aluminum zinc wire through plasma cladding technology. Its surface morphology is good without crack defects. The role of tungsten carbide is to strengthen as the second phase, forming a good strengthening synergistic effect, and avoiding segregation in the thickness direction of the wear-resistant layer due to a large amount of carbides. Rare earth oxide La2O3 tends to segregate at grain boundaries or phase boundaries. While reducing the melting point of the alloy system, it promotes the melting and decomposition of the surface of tungsten carbide particles, not only improving the wettability between tungsten carbide and the substrate and promoting the formation of a good metallurgical bond with the metal matrix, but also the precipitated fine tungsten carbide can increase the hardness of the cobalt-based matrix and reduce the cracking tendency of the cladding layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic diagram of the zinc pot roller system of the existing hot-dip high-aluminum zinc unit;

[0034] Figure 2 is a schematic diagram of the shaft sleeve and bearing bush of the zinc pot roller of the existing hot-dip high-aluminum zinc unit. (a) is the assembly drawing of the shaft sleeve and bearing bush of the zinc pot roller of the hot-dip high-aluminum zinc unit, and (b) is the cross-sectional view of the shaft sleeve and bearing bush of the zinc pot roller of the hot-dip high-aluminum zinc unit;

[0035] Figure 3 is the preparation flow chart of the cladding layer for the shaft sleeve at the shaft head of the zinc pot roller of the hot-dip high-aluminum zinc wire of the present invention;

[0036] Figure 4 is a sample diagram of the cladding layer for the shaft sleeve at the shaft head of the zinc pot roller of the hot-dip high-aluminum zinc wire prepared in Example 1 of the present invention;

[0037] Figure 5 is the cross-sectional tissue distribution diagram of the wear-resistant layer of the shaft sleeve wear-resistant layer sample of Example 1 of the present invention at a scale of 100 microns;

[0038] Figure 6 is the morphology diagram of the bonding phase of the wear-resistant layer of the shaft sleeve wear-resistant layer sample of Example 1 of the present invention at 10 microns;

[0039] Figure 7 is the morphology diagram of the WC balls of the wear-resistant layer of the shaft sleeve wear-resistant layer sample of Example 1 of the present invention at 20 microns;

[0040] Figure 8 is the part with a wear-resistant layer prepared in Example 2 of the present invention. (a) is the schematic diagram of the penetrant inspection of the wear-resistant layer after plasma cladding, and (b) is the schematic diagram of the surface of the part after grinding. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] In order to better understand the above technical solutions of the present invention, the technical solutions of the present invention will be further described below with reference to the drawings and embodiments.

[0042] A cladding layer for the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire provided by the present invention comprises the following components by mass percentage: cast tungsten carbide: 30-50%, La2O3 powder: 1-3%, and the balance is cobalt-based alloy powder; the cobalt-based alloy powder comprises the following components by mass percentage: C: 1-3%, W: 5.0-10%, Cr: 25.0-30.0%, Si≤2.0%, Fe≤2.0%, Mo: 1.5-2.0%, and the balance is Co and unavoidable impurities.

[0043] In a specific embodiment, the Si content is 1.0-2.0% and the Fe content is 1.0-2.0%.

[0044] The design principle of the components of the above-mentioned cladding layer for the shaft sleeve of the zinc pot roller shaft head of the hot-dip high-aluminum zinc wire is as follows:

[0045] In the cobalt-based alloy, tungsten, molybdenum, and chromium can all combine with carbon to form dispersed tungsten carbide to enhance the strength of the matrix. These carbides dispersed and dissolved in the cobalt-based matrix and the externally added cast tungsten carbide together play a role in increasing the strength and hot hardness of the cladding layer. Cast tungsten carbide is used as a hard phase, which greatly increases the wear resistance of the cladding layer while improving the overall hardness of the cladding layer; rare earth oxide La2O3 tends to segregate at grain boundaries or phase boundaries. While reducing the melting point of the alloy system, it promotes the melting and decomposition of the surface of tungsten carbide particles, not only improving the wettability of tungsten carbide with the base material and promoting the formation of good metallurgical bonding with the metal matrix, but also the precipitated fine tungsten carbide can increase the hardness of the matrix and reduce the cracking tendency of the cladding layer.

[0046] The Shore hardness HL of the cladding layer for the shaft sleeve of the zinc pot roller shaft head of the hot-dip high-aluminum zinc wire is ≥700, and the Rockwell hardness HRC is ≥50.

[0047] Combined Figure 3 As shown, the present invention also provides a preparation method for the cladding layer of the shaft sleeve of the zinc pot roller shaft head of the hot-dip high-aluminum zinc wire, comprising the following steps:

[0048] S1. Surface pretreatment is carried out on the metal shaft sleeve substrate to remove the surface oxide layer;

[0049] Specifically, surface pretreatment is carried out on the metal shaft sleeve substrate, and the surface oxide layer is removed by grinding, and it is reserved after cleaning and drying; acetone or gasoline can be used during cleaning.

[0050] S2. The cobalt-based alloy powder, cast tungsten carbide powder, and La2O3 powder are configured according to the component ratio of the above-mentioned cladding layer for the shaft sleeve of the zinc pot roller shaft head of the hot-dip high-aluminum zinc wire, and after being fully mixed, vacuum drying is carried out to obtain the cladding powder;

[0051] Specifically, after configuring cobalt-based alloy powder, cast tungsten carbide powder, and La2O3 powder according to the composition ratio of the cladding layer of the shaft sleeve for the zinc pot roller head of hot-dip high-aluminum zinc wire, they are fully mixed in a double-cone mixer for 12 to 48 hours, and then vacuum-dried to obtain the cladding powder for standby. Among them, the cobalt-based alloy powder is produced by the gas atomization process, the cast tungsten carbide powder is produced by the plasma remelting and spheroidizing method, and the La2O3 powder is prepared by the precipitation method; the particle sizes of the cobalt-based alloy powder and the cast tungsten carbide powder are 40 to 150 μm, and the particle size of the La2O3 powder is 1 to 10 μm. During vacuum drying, the drying temperature is 100 to 200 °C, and the drying time is 3 to 10 hours.

[0052] S3. Using the synchronous powder feeding method, the cladding powder obtained in step S2 is subjected to plasma cladding under the protection of an inert gas to form a plasma cladding layer on the surface of the metal shaft sleeve substrate;

[0053] Specifically, the cladding powder is subjected to plasma cladding by using a synchronous powder feeding plasma arc cladding device under the protection of an inert gas to form a plasma cladding layer on the surface of the metal shaft sleeve substrate. Among them, during the plasma cladding process, the working current is 300 to 400 A, the scanning speed is 75 to 200 mm / min, the distance between the nozzle and the metal shaft sleeve substrate is 10 to 50 mm, the overlapping rate is 40 to 60%, and the powder feeding rate is 30 to 100 g / min. The inert gas is Ar, the flow rate of the shielding gas is 0.5 to 1.0 m 3 / h, the flow rate of the powder feeding gas is 0.5 to 1.0 m 3 / h, and the flow rate of the plasma gas is 0.5 to 1.0 m 3 / h.

[0054] In a specific embodiment, the number of plasma cladding passes is 1 to 2 passes, specifically depending on the final thickness required by the product. The cladding thickness of a single pass is 2.0 to 3.0 mm. Among them, after a single pass of cladding, a plasma cladding layer with a thickness of 2.5 to 3.5 mm is obtained; after 2 passes of cladding, a plasma cladding layer with a thickness of 4.0 to 6.0 mm is obtained.

[0055] S4. The metal shaft sleeve with the plasma cladding layer is naturally cooled in a heat preservation furnace.

[0056] Specifically, the metal shaft sleeve with the plasma cladding layer on its surface is placed in a closed heat preservation furnace for slow natural cooling, and the cooling time is 36 to 48 hours.

[0057] The cladding layer of the bushing for the zinc pot roller shaft head of the hot-dip high-aluminum zinc wire is obtained by the above preparation method, and its thickness is between 2.0 and 6.0 mm (the thickness of single-pass cladding is 2.5 - 3.5 mm, and the thickness of two-pass cladding is 4.0 - 6.0 mm). Its Leeb hardness HL ≥ 700, and Rockwell hardness HRC ≥ 50.

[0058] The following further introduces the cladding layer of the bushing for the zinc pot roller shaft head of the hot-dip high-aluminum zinc wire and its preparation method of the present invention in combination with specific examples;

[0059] Example 1

[0060] The preparation process of the cladding layer of the bushing for the zinc pot roller shaft head of the hot-dip high-aluminum zinc wire in this example is as follows:

[0061] (1) Perform surface pretreatment on the metal bushing substrate, grind to remove the surface oxide layer, grind its surface to be flat and bright, then use acetone or gasoline, etc. to clean the substrate to remove surface oil stains, and set aside after drying.

[0062] (2) Configure cobalt-based alloy powder, cast tungsten carbide and La2O3 powder in proportion; the proportion of cast tungsten carbide is 30%, and the proportion of La2O3 powder is 2%, and the rest is cobalt-based alloy powder, calculated by mass percentage; among them, the cobalt-based alloy powder includes the following components by mass percentage: C: 1.2%, W: 6.0%, Cr: 28%, Si: 1%, Fe: 1%, Mo: 1.5%, and the rest is Co and inevitable impurities;

[0063] Among the above powders used, the cobalt-based alloy powder is produced by gas atomization process, the cast tungsten carbide powder is produced by plasma remelting and spheroidization method, the La2O3 powder is prepared by precipitation method, the particle size of the cobalt-based alloy powder and cast tungsten carbide is 40 - 150 μm, and the particle size of the La2O3 powder is 1 - 10 μm. Put the above proportioned powders into a double-cone mixer for full mixing, the mixing time is 24 h, after mixing, put them into a vacuum drying oven for vacuum drying, the drying temperature is set at 150 °C, and the drying time is 3 hours to finally obtain the cladding powder;

[0064] (3) Use the synchronous powder feeding method for the above obtained cladding powder, and perform one-pass plasma cladding under the protection of inert gas by using a synchronous powder feeding plasma arc cladding device to obtain a plasma cladding layer with good surface forming. The plasma cladding process parameters are as follows: the working current is 300 A, the scanning speed is 100 mm / min, the distance between the nozzle and the metal bushing substrate is 20 mm, the overlap rate is 50%, and the powder feeding rate is 40 g / min; the inert gas is Ar, the flow rate of the shielding gas is 0.75 m 3 / h, the powder feeding gas flow rate is 0.75 m 3 / h, and the plasma gas flow rate is 0.75 m3 / h.

[0065] (4) Place the metal bushing with a plasma clad layer on its surface in a well-sealed heat preservation furnace and let it cool naturally. The cooling time is 48 h, and a clad layer for the shaft head of the zinc pot roller for hot-dip high-aluminum zinc wire with a thickness of 3.0 mm can be obtained.

[0066] Perform performance testing on the clad layer for the shaft head of the zinc pot roller for the hot-dip high-aluminum zinc wire prepared above. Use a wire cutting machine to cut the clad layer into small sample pieces as shown in Figure 4 The outer arc surface is shown. After grinding and polishing the cross-sectional sample, observe it with a scanning electron microscope to obtain Figure 5 , Figure 6 , Figure 7 ; among them Figure 5 is the cross-sectional microstructure distribution diagram of the clad layer observed at a scale of 100 microns. The spherical shapes in the figure are WC particles, and their mass fraction is 31.5%; Figure 6 is the bonding phase of the clad layer observed at a scale of 10 microns, that is, there are no WC particles. It can be seen that the bonding phase structure is uniform; Figure 7 is the morphology diagram of WC balls at a scale of 20 microns. It can be seen that the WC balls and the surrounding alloy components show a metallurgical bonding morphology.

[0067] Perform hardness testing on the clad layer for the shaft head of the zinc pot roller for the hot-dip high-aluminum zinc wire above. Use a Leeb hardness tester to measure its hardness. Select five points on the working surface of the clad layer, measure each point 5 times, and take the average value. The measurement results are shown in Table 1. The Leeb hardness HL of the clad layer for the shaft head of the zinc pot roller for the hot-dip high-aluminum zinc wire is ≥700, and the Rockwell hardness HRC is ≥50. Its hardness meets the expectations and has good application prospects.

[0068] Table 1 Hardness of the clad layer sample in Example 1

[0069] Position Shore hardness HL Rockwell hardness HRC 1 737 52.6 2 719 50.4 3 768 56.9 4 728 51.5 5 709 50.1 Mean value 732 52.3

[0070] Example 2

[0071] The preparation process of the clad layer for the shaft head of the zinc pot roller for the hot-dip high-aluminum zinc wire in this example is as follows:

[0072] (1) Perform surface pretreatment on the metal bushing substrate. Grind and remove the surface oxide layer, grind its surface flat and bright, and then use acetone or gasoline, etc. to clean the substrate to remove surface oil stains. After drying, it is ready for use.

[0073] (2) Configure cobalt-based alloy powder, cast tungsten carbide, and La2O3 powder in proportion; the proportion of cast tungsten carbide is 45%, the proportion of La2O3 powder is 3%, and the rest is cobalt-based alloy powder, by mass percentage; among them, the cobalt-based alloy powder includes the following components by mass percentage: C: 1.2%, W: 6.0%, Cr: 28%, Si: 1%, Fe: 1%, Mo: 1.5%, and the rest is Co and unavoidable impurities;

[0074] Among the powders used above, the cobalt-based alloy powder is produced by gas atomization process, the cast tungsten carbide powder is produced by plasma remelting and spheroidizing method, and the La2O3 powder is prepared by precipitation method. The particle sizes of the cobalt-based alloy powder and cast tungsten carbide are 40 - 150 μm, and the particle size of the La2O3 powder is 1 - 10 μm. Put the above-prepared powders into a double-cone mixer for sufficient mixing, the mixing time is 24 h, after mixing, put them into a vacuum drying oven for vacuum drying, the drying temperature is set at 200 °C, and the drying time is 3 hours to finally obtain the clad powder;

[0075] (3) Use the synchronous powder feeding method for the above-obtained clad powder, and carry out one-pass plasma cladding under the protection of inert gas by using a synchronous powder feeding plasma arc cladding device to obtain a plasma cladding layer with good surface forming. The plasma cladding process parameters are as follows: the working current is 300 A, the scanning speed is 75 mm / min, the distance between the nozzle and the metal bushing substrate is 20 mm, the overlapping rate is 50%, and the powder feeding rate is 40 g / min; the inert gas is Ar, the flow rate of the shielding gas is 0.75 m 3 / h, the flow rate of the powder feeding gas is 0.75 m 3 / h, and the flow rate of the plasma gas is 0.75 m 3 / h.

[0076] (4) Put the metal bushing with a plasma cladding layer on the surface into a well-sealed heat preservation furnace for natural cooling, and the cooling time is 48 h, then a bushing cladding layer with a thickness of 3.5 mm for the shaft head of the hot-dip high-aluminum zinc wire zinc pot roller can be obtained.

[0077] Combined Figure 8 As shown in (a) in, perform coloring flaw detection on the bushing cladding layer for the shaft head of the hot-dip high-aluminum zinc wire zinc pot roller prepared in this embodiment, and there are no cracks on the entire cladding surface; combined Figure 8 As shown in (b) in, after grinding the bushing cladding layer for the shaft head of the hot-dip high-aluminum zinc wire zinc pot roller, the surface of the product shows a metallic luster and has no defects such as cracks and pores.

[0078] In the bushing cladding layer for the shaft head of the hot-dip high-aluminum zinc wire zinc pot roller prepared in this embodiment, the content of WC is 45%, the Leeb hardness HL is 788, and the Rockwell hardness HRC is 57.2, which can meet the requirements of the high-aluminum zinc working conditions.

[0079] Example 3

[0080] The preparation process of the cladding layer of the bushing for the zinc pot roller shaft head of the hot-dip high-aluminum zinc wire in this example is as follows:

[0081] (1) Perform surface pretreatment on the metal bushing substrate, grind to remove the surface oxide layer, grind its surface to be flat and bright, then use acetone or gasoline, etc. to clean the substrate to remove surface oil stains, and dry it for later use.

[0082] (2) Configure cobalt-based alloy powder, cast tungsten carbide and La2O3 powder in proportion; the proportion of cast tungsten carbide is 50%, the proportion of La2O3 powder is 1%, and the rest is cobalt-based alloy powder, calculated by mass percentage; among them, the cobalt-based alloy powder includes the following components calculated by mass percentage: C: 1.0%, W: 5.0%, Cr: 25%, Si: 1%, Fe: 1%, Mo: 1.5%, and the rest is Co and inevitable impurities;

[0083] All the powders used above are produced by the aerosol process. The particle sizes of the cobalt-based alloy powder and cast tungsten carbide are 40 - 150 μm, and the particle size of the La2O3 powder is 1 - 10 μm. Put the above-prepared powders into a double-cone mixer for sufficient mixing. The mixing time is 48 h. After mixing, put them into a vacuum drying oven for vacuum drying. The drying temperature is set at 200 °C, and the drying time is 6 hours. Finally, the cladding powder is obtained;

[0084] (3) Use the synchronous powder feeding method for the above-obtained cladding powder, and perform 2 passes of plasma cladding under the protection of inert gas by using a synchronous powder feeding plasma arc cladding device to obtain a plasma cladding layer with good surface forming. The plasma cladding process parameters are as follows: the working current is 400 A, the scanning speed is 80 mm / min, the distance between the nozzle and the metal bushing substrate is 50 mm, the overlapping rate is 40%, and the powder feeding rate is 30 g / min; the inert gas is Ar, the flow rate of the protection gas is 0.5 m 3 / h, the flow rate of the powder feeding gas is 0.5 m 3 / h, and the flow rate of the plasma gas is 0.5 m 3 / h.

[0085] (4) Put the metal bushing with a plasma cladding layer on its surface into a heat preservation furnace with good sealing performance for natural cooling. The cooling time is 36 h, and a bushing cladding layer for the zinc pot roller shaft head of the hot-dip high-aluminum zinc wire with a thickness of 6.0 mm can be obtained.

[0086] The Leeb hardness HL of the bushing cladding layer for the zinc pot roller shaft head of the hot-dip high-aluminum zinc wire prepared in this example is 804, and the Rockwell hardness HRC is 59.2, which can meet the requirements of the high-aluminum zinc working conditions.

[0087] Example 4

[0088] The preparation process of the cladding layer for the shaft sleeve at the shaft head of the hot-dip high-aluminum zinc wire zinc pot in this example is as follows:

[0089] (1) Perform surface pretreatment on the metal shaft sleeve substrate, grind to remove the surface oxide layer, grind its surface to be flat and bright, then use acetone or gasoline, etc. to clean the substrate to remove surface oil stains, and set aside after drying.

[0090] (2) Configure cobalt-based alloy powder, cast tungsten carbide, and La2O3 powder in proportion; the proportion of cast tungsten carbide is 30%, the proportion of La2O3 powder is 3%, and the rest is cobalt-based alloy powder, by mass percentage; among them, the cobalt-based alloy powder includes the following components by mass percentage: C: 1.5%, W: 10.0%, Cr: 30%, Si: 2%, Fe: 2%, Mo: 2.0%, and the rest is Co and inevitable impurities;

[0091] All the powders used above are produced by the aerosol method. The particle sizes of the cobalt-based alloy powder and cast tungsten carbide are 40 - 150 μm, and the particle size of the La2O3 powder is 1 - 10 μm. Put the above-prepared powders into a double-cone mixer for full mixing. The mixing time is 12 h. After mixing, put them into a vacuum drying oven for vacuum drying. The drying temperature is set at 120 °C, and the drying time is 10 hours to finally obtain the cladding powder;

[0092] (3) Use the synchronous powder feeding method for the above-obtained cladding powder, and perform 2 passes of plasma cladding under the protection of inert gas by using a synchronous powder feeding plasma arc cladding device to obtain a plasma cladding layer with good surface forming. The plasma cladding process parameters are as follows: the working current is 350 A, the scanning speed is 200 mm / min, the distance between the nozzle and the metal shaft sleeve substrate is 10 mm, the overlapping rate is 60%, and the powder feeding rate is 100 g / min; the inert gas is Ar, the flow rate of the protection gas is 1.0 m 3 / h, the flow rate of the powder feeding gas is 1.0 m 3 / h, and the flow rate of the plasma gas is 1.0 m 3 / h.

[0093] (4) Put the metal shaft sleeve with a plasma cladding layer on its surface into a heat preservation furnace with good sealing performance for natural cooling. The cooling time is 48 h, and a shaft sleeve cladding layer with a thickness of 5.0 mm for the shaft head of the hot-dip high-aluminum zinc wire zinc pot can be obtained.

[0094] The Leeb hardness HL of the shaft sleeve cladding layer for the shaft head of the hot-dip high-aluminum zinc wire zinc pot prepared in this example is 725, and the Rockwell hardness HRC is 52.2, which can meet the requirements of the high-aluminum zinc working conditions.

[0095] Those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. As long as within the scope of the spirit of the present invention, changes and modifications to the above-described embodiments will fall within the scope of the claims of the present invention.

Claims

1. A cladding layer for the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire, characterized in that, It includes the following components by mass percentage: cast tungsten carbide: 30 - 50%, La2O3 powder: 1 - 3%, and the balance is cobalt-based alloy powder; The cobalt-based alloy powder includes the following components by mass percentage: C: 1 - 3%, W: 5.0 - 10%, Cr: 25.0 - 30.0%, Si ≤ 2.0%, Fe ≤ 2.0%, Mo: 1.5 - 2.0%, and the balance is Co and unavoidable impurities.

2. The cladding layer for the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire according to claim 1, characterized in that, In the cobalt-based alloy powder, the Si content is 1.0 - 2.0% and the Fe content is 1.0 - 2.0%.

3. The cladding layer for the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire according to claim 1, characterized in that, The Leeb hardness HL of the clad layer of the bushing for the zinc pot roller shaft head of hot-dip high-aluminum zinc wire is ≥700, and the Rockwell hardness HRC is ≥50.

4. A preparation method for the cladding layer of the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire, characterized in that, It includes the following steps: S1. Surface-pre-treat the metal bushing substrate to remove the surface oxide layer; S2. Configure the cobalt-based alloy powder, cast tungsten carbide powder and La2O3 powder according to the components of the clad layer of the bushing for the zinc pot roller shaft head of hot-dip high-aluminum zinc wire as described in Claim 1 or 2, fully mix them and then perform vacuum drying to obtain the clad powder; S3. Adopt the synchronous powder feeding method for the clad powder obtained in Step S2, and perform plasma cladding under the protection of inert gas to form a plasma clad layer on the surface of the metal bushing substrate; S4. Naturally cool the metal bushing with the plasma clad layer on its surface in a holding furnace.

5. The preparation method for the cladding layer of the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire according to claim 4, characterized in that, In Step S2, the particle sizes of the cobalt-based alloy powder and the cast tungsten carbide powder are 40 - 150 μm, and the particle size of the La2O3 powder is 1 - 10 μm.

6. The preparation method for the cladding layer of the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire according to claim 4, characterized in that, In Step S2, the cobalt-based alloy powder, cast tungsten carbide powder and La2O3 powder are mixed in a double-cone mixer, and the mixing time is 12 - 48 h.

7. The preparation method for the cladding layer of the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire according to claim 4, characterized in that, In Step S2, the drying temperature of the vacuum drying is 100 - 200 °C, and the drying time is 3 - 10 h.

8. The preparation method for the cladding layer of the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire according to claim 4, characterized in that, In Step S3: During the plasma cladding process, the working current is 300 - 400 A, the scanning speed is 80 - 200 mm / min, the distance between the nozzle and the metal bushing substrate is 10 - 50 mm, the overlapping rate is 40 - 60%, and the powder feeding rate is 30 - 100 g / min; and / or The inert gas used is Ar, and the flow rate of the shielding gas is 0.5 to 1.0 m 3 / h, the powder feeding gas flow rate is 0.5 to 1.0 m 3 / h, and the plasma gas flow rate is 0.5 to 1.0 m 3 / h.

9. The preparation method for the cladding layer of the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire according to claim 4, characterized in that, In Step S3, during the plasma cladding process, the number of plasma cladding passes is 1 - 2 passes, and the cladding thickness of a single pass is 2.0 - 3.0 mm.

10. The preparation method for the cladding layer of the shaft sleeve of the zinc pot roller shaft head of a hot-dip high-aluminum zinc wire according to claim 4, characterized in that, In Step S4, the natural cooling time of the metal bushing with the clad layer in the closed holding furnace is 36 - 48 h.

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