Self-protection flux-cored wire for surfacing repair, preparation method thereof and surfacing method

Abstract

The application relates to a self-protection cored wire for surfacing repair, which is composed of the following elements in percentage by mass: 0.4-0.6% of C, 1.31-1.72% of B, 1.32-1.78% of Si, 0.12-0.19% of Mn, 0.12-0.18% of Al, 0.08-0.12% of Mg, 12.0-14.4% of Cr, 2.1-2.7% of Mo, 0.56-0.75% of W, 4.5-5.4% of Ni, and the balance of Fe. The self-protection cored wire for surfacing repair has excellent welding performance, and does not contain inorganic minerals and ceramic oxides, so that the surfacing layer formed by surfacing is not prone to cracking; meanwhile, the self-protection cored wire does not contain expensive elements such as rare earth and Nb, and has low cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of welding, in particular to surfacing. BACKGROUND

[0002] Modern heavy trucks and other heavy machinery parts, such as rotating shafts, large gears and the like, have the phenomenon of wear and failure. With the increasing degree of automation in modern high technology, the running speed of such parts is faster, and there is almost no "rest" or maintenance time, so it is inevitable that the wear speed and degree are faster and faster, and even in the case of accidental accidents or erosion, serious failure phenomena such as partial small volume fracture and shedding occur. The self-protection flux-cored wire can repair defective parts or prepare composite parts through surfacing process, so that the size of the part can be repaired or achieved while the function of the part is maintained. The structural surfacing layer formed by such wire needs to meet the following requirements: high hardness to maintain the wear resistance of the part material itself; the surfacing layer and the more base material part can be metallurgically combined, and are not prone to fracture at the interface after long-term use; the surfacing layer has high toughness and can form a thick structure without cracking, which affects its application range; the wire needs to have good weldability, no spatter, no arc, the surfacing layer formed has no pores and good appearance; the cost of the wire is low, and the use amount of rare earth and heavy transition metals is reduced.

[0003] At present, in order to improve wear resistance and self-protection, self-protection flux-cored wires increase enough inorganic minerals or ceramic oxides in the formula, which leads to poor weldability, and the surfacing layer is prone to cracking after a certain thickness, thereby reducing the application range of the wire. Or directly adding hard metal compounds such as tungsten carbide and chromium carbide in the formula, the proportion of high-carbon chromium iron is very high (> 50%), and rare earth metals are also used as protective agents, which greatly increases the cost of the wire. SUMMARY

[0004] The embodiments of the present application provide a self-protection flux-cored wire for surfacing repair and a surfacing method to solve the technical problems of easy cracking and high cost of self-protection flux-cored wires.

[0005] In a first aspect, the embodiments of the present application provide a self-protection flux-cored wire for surfacing repair. The flux of the self-protection flux-cored wire for surfacing repair is composed of the following elements in mass percentage: 0.4-0.6% of C, 1.31-1.72% of B, 1.32-1.78% of Si, 0.12-0.19% of Mn, 0.12-0.18% of Al, 0.08-0.12% of Mg, 12.0-14.4% of Cr, 2.1-2.7% of Mo, 0.56-0.75% of W, 4.5-5.4% of Ni, and the balance of Fe.

[0006] In some embodiments of the present application, the flux of the surfacing repair self-shielded flux-cored wire comprises the following components:

[0007] Tungsten iron powder, low-carbon chromium iron powder, boron carbide powder, silicon iron powder, nickel powder, aluminum magnesium alloy powder, molybdenum iron powder, silicon manganese alloy powder, iron powder.

[0008] In some embodiments of the present application, the content of W in the tungsten iron powder is 75%, and the balance is Fe; and / or,

[0009] The content of C in the low-carbon chromium iron powder is 0.15% to 0.5%, the content of chromium is 60%, and the balance is Fe; and / or,

[0010] The content of Si in the silicon iron powder is 85%, and the balance is Fe; and / or,

[0011] The content of Al in the aluminum magnesium alloy powder is 62%, and the balance is Mg; and / or,

[0012] The content of Mo in the molybdenum iron powder is 60%, and the balance is Fe; and / or,

[0013] The content of Mn in the silicon manganese alloy powder is 64%, the content of Si is 27%, and the balance is Fe.

[0014] In some embodiments of the present application, the flux of the surfacing repair self-shielded flux-cored wire is composed of the following raw materials in mass percentage: 1.8% to 2.2% tungsten iron powder, 20% to 24% low-carbon chromium iron powder, 1.8% to 2.2% boron carbide powder, 1.5% to 2% silicon iron powder, 4.5% to 5.2% nickel powder, 0.2% to 0.3% aluminum magnesium alloy powder, 3.5% to 4.5% molybdenum iron powder, 0.2% to 0.3% silicon manganese alloy powder, and the balance is iron powder.

[0015] In a second aspect, the embodiments of the present application provide a preparation method of a surfacing repair self-shielded flux-cored wire, which comprises the following steps:

[0016] Providing a metal powder raw material;

[0017] Preparation of the flux-cored wire with the metal powder raw material as the flux to obtain a surfacing repair self-shielded flux-cored wire,

[0018] The metal powder raw material is composed of the following elements in percentage of the mass of the metal powder raw material: 0.4-0.6% of C, 1.31-1.72% of B, 1.32-1.78% of Si, 0.12-0.19% of Mn, 0.12-0.18% of Al, 0.08-0.12% of Mg, 12.0-14.4% of Cr, 2.1-2.7% of Mo, 0.56-0.75% of W, 4.5-5.4% of Ni, and the balance of Fe.

[0019] In some embodiments of the present application, the metal powder raw material is provided by the following steps:

[0020] The tungsten-iron powder, low-carbon chromium-iron powder, boron carbide powder, silicon-iron powder, nickel powder, aluminum-magnesium alloy powder, molybdenum-iron powder, silicon-manganese alloy powder and iron powder are mixed.

[0021] In some embodiments of the present application, the content of W in the tungsten-iron powder is 75%, and the balance is Fe; and / or,

[0022] The content of C in the low-carbon chromium-iron powder is 0.15-0.5%, the content of Cr is 60%, and the balance is Fe; and / or,

[0023] The content of Si in the silicon-iron powder is 85%, and the balance is Fe; and / or,

[0024] The content of Al in the aluminum-magnesium alloy powder is 62%, and the balance is Mg; and / or,

[0025] The content of Mo in the molybdenum-iron powder is 60%, and the balance is Fe; and / or,

[0026] The content of Mn in the silicon-manganese alloy powder is 64%, the content of Si is 27%, and the balance is Fe.

[0027] In some embodiments of the present application, the metal powder raw material is composed of the following raw materials in percentage of the mass of the metal powder raw material: 1.8-2.2% of tungsten-iron powder, 20-24% of low-carbon chromium-iron powder, 1.8-2.2% of boron carbide powder, 1.5-2% of silicon-iron powder, 4.5-5.2% of nickel powder, 0.2-0.3% of aluminum-magnesium alloy powder, 3.5-4.5% of molybdenum-iron powder, 0.2-0.3% of silicon-manganese alloy powder, and the balance of iron powder.

[0028] In some embodiments of the present application, the particle size of the metal powder raw material is not greater than 250 um.

[0029] In a third aspect, the embodiments of the present application provide a surfacing method, which is performed by the surfacing repair self-shielded flux-cored wire according to any one of the first aspect or the method for preparing the surfacing repair self-shielded flux-cored wire according to any one of the second aspect,

[0030] The surfacing voltage is 32-34V,

[0031] The surfacing current is 300-350A,

[0032] The surfacing speed is 30-40cm / min,

[0033] The dry elongation is 18-22mm,

[0034] The post-weld state is natural air cooling.

[0035] Compared with the prior art, the above technical solutions provided by the embodiments of the present application have the following advantages:

[0036] The surfacing repair self-shielded flux-cored wire provided by the embodiments of the present application has excellent welding performance, and does not contain inorganic minerals and ceramic oxides, so that the surfacing layer formed by surfacing is not easy to crack; at the same time, it does not contain expensive elements such as rare earth and Nb, and has low cost. BRIEF DESCRIPTION OF DRAWINGS

[0037] The drawings incorporated into the specification and forming a part thereof, illustrate embodiments consistent with the present application and together with the description serve to explain the principles of the present application.

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows, and obviously, other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0039] Figure 1 The appearance photo of the surfacing wear-resistant test sample plate corresponding to the embodiment 1 of the present application;

[0040] Figure 2 The cross-section photo of the surfacing wear-resistant test sample plate corresponding to the embodiment 1 of the present application;

[0041] Figure 3 The appearance photo of the surfacing cracking test sample plate corresponding to the comparative example 2 of the present application. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the drawings in the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present application.

[0043] Unless otherwise specifically defined, the terms used herein are understood as having the meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as generally understood by those skilled in the art to which the present application belongs. If there is a conflict, the present specification takes precedence.

[0044] Unless otherwise specifically stated, the various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0045] The existing self-protection drug wire has the technical problems of easy cracking and high cost.

[0046] The technical solutions provided by the embodiments of the present application are to solve the above technical problems, and the general idea is as follows:

[0047] In a first aspect, the embodiments of the present application provide a self-protection flux-cored wire for surfacing repair, wherein the flux of the self-protection flux-cored wire for surfacing repair is composed of the following elements in mass percentage: 0.4% to 0.6% of C, 1.31% to 1.72% of B, 1.32% to 1.78% of Si, 0.12% to 0.19% of Mn, 0.12% to 0.18% of Al, 0.08% to 0.12% of Mg, 12.0% to 14.4% of Cr, 2.1% to 2.7% of Mo, 0.56% to 0.75% of W, 4.5% to 5.4% of Ni, and the balance of Fe.

[0048] In the self-protection flux-cored wire for surfacing repair, the functions of each element are as follows:

[0049] Carbon is an austenite forming element, has important strengthening and deoxidizing effect, but also reduces the impact toughness of the material, and needs to control the proportion and addition form of carbon and other transition metals.

[0050] Chromium can produce solid solution strengthening and is the main element for forming hard phases such as carbides, but too high content will affect the impact toughness of the surfacing layer.

[0051] Molybdenum is a carbide forming element, and the formed solid solution and carbide are distributed in the surfacing metal organization, which is beneficial to improve the hardness of the surfacing layer and can refine the metal grains and improve the toughness of the surfacing layer. However, too much Mo can hinder the diffusion of carbon and inhibit the combination process of C and other elements.

[0052] Tungsten can increase the hardenability of the surfacing layer, produce solid solution strengthening, inhibit temper brittleness, and appropriate addition is beneficial to the improvement of impact toughness and is one of important elements for improving the high-temperature stability of the material.

[0053] Silicon is a strong ferrite forming element, which improves solid solution strengthening and has a deoxidizing effect, reduces the oxygen content in the weld, and can make the large particles of low-melting-point oxides in the surfacing layer float up, thereby reducing the adverse effects of oxygen on the weld metal.

[0054] Manganese can improve the hardenability and has good deoxidizing and desulfurizing effect, and the combined effect of manganese and silicon is beneficial to reduce the oxygen content in the weld and improve the heat crack resistance of the weld. However, too much Mn will coarsen the material grains, reduce the ductility and toughness.

[0055] Nickel can maintain high strength of the surfacing layer while maintaining high toughness, and can also improve certain corrosion resistance.

[0056] Boron is an important alloying element, which can also improve the amorphous forming ability of the surfacing layer, and appropriate ratio can inhibit crystallization and make the grains more refined. At the same time, it is a deoxidizing agent, which can reduce pores, stabilize the arc and reduce spatter.

[0057] Aluminum has a strong binding force with oxygen, which can deoxidize and denitrogenize, and a certain value can significantly inhibit the generation of pores, stabilize the arc, reduce the generation of welding smoke, but may reduce the hardness.

[0058] Magnesium can deoxidize and denitrogenize, and also can improve the fluidity of the welding melt and improve the appearance state.

[0059] The content range of the above elements is reasonably limited in the application, so that the self-shielded flux-cored wire for surfacing repair with excellent welding performance can be obtained.

[0060] The self-shielded flux-cored wire for surfacing repair provided by the application has excellent welding performance, and does not contain inorganic minerals and ceramic oxides, and the surfacing layer formed by the surfacing thereof is not easy to crack; at the same time, it does not contain expensive elements such as rare earth and Nb, and the cost is low.

[0061] In some embodiments of the application, the flux of the self-shielded flux-cored wire for surfacing repair comprises the following components:

[0062] Tungsten iron powder, low-carbon chromium iron powder, boron carbide powder, silicon iron powder, nickel powder, aluminum magnesium alloy powder, molybdenum iron powder, silicon manganese alloy powder, iron powder.

[0063] The above components are all inexpensive and readily available raw materials, which are easy to process.

[0064] In some embodiments of the present application, the tungsten iron powder contains 75% of W and the balance of Fe; and / or,

[0065] The low-carbon chromium iron powder contains 0.15% to 0.5% of C, 60% of Cr, and the balance of Fe; and / or,

[0066] The silicon iron powder contains 85% of Si and the balance of Fe; and / or,

[0067] The aluminum magnesium alloy powder contains 62% of Al and the balance of Mg; and / or,

[0068] The molybdenum iron powder contains 60% of Mo and the balance of Fe; and / or,

[0069] The silicon manganese alloy powder contains 64% of Mn, 27% of Si, and the balance of Fe.

[0070] In some embodiments of the present application, the flux of the surfacing repair self-shielded flux-cored wire is composed of the following raw materials in terms of mass percentage: 1.8% to 2.2% of tungsten iron powder, 20% to 24% of low-carbon chromium iron powder, 1.8% to 2.2% of boron carbide powder, 1.5% to 2% of silicon iron powder, 4.5% to 5.2% of nickel powder, 0.2% to 0.3% of aluminum magnesium alloy powder, 3.5% to 4.5% of molybdenum iron powder, 0.2% to 0.3% of silicon manganese alloy powder, and the balance of iron powder.

[0071] In a second aspect, the embodiments of the present application provide a preparation method of a surfacing repair self-shielded flux-cored wire, which comprises the following steps:

[0072] S1: providing a metal powder raw material;

[0073] S2: preparing a flux-cored wire with the metal powder raw material as a flux to obtain a surfacing repair self-shielded flux-cored wire,

[0074] The metal powder raw material is composed of the following elements in percentage of the mass of the metal powder raw material: 0.4%-0.6% of C, 1.31%-1.72% of B, 1.32%-1.78% of Si, 0.12%-0.19% of Mn, 0.12%-0.18% of Al, 0.08%-0.12% of Mg, 12.0%-14.4% of Cr, 2.1%-2.7% of Mo, 0.56%-0.75% of W, 4.5%-5.4% of Ni, and the balance of Fe.

[0075] The metal powder raw material can be prepared into a flux-cored wire by a method known in the art, such as a drawing method or an extrusion method.

[0076] In some embodiments of the present application, the metal powder raw material is prepared by the following steps:

[0077] The tungsten-iron powder, low-carbon chromium-iron powder, boron carbide powder, silicon-iron powder, nickel powder, aluminum-magnesium alloy powder, molybdenum-iron powder, silicon-manganese alloy powder, and iron powder are mixed.

[0078] In some embodiments of the present application, the tungsten-iron powder contains 75% of W and the balance of Fe; and / or,

[0079] The low-carbon chromium-iron powder contains 0.15%-0.5% of C, 60% of Cr, and the balance of Fe; and / or,

[0080] The silicon-iron powder contains 85% of Si and the balance of Fe; and / or,

[0081] The aluminum-magnesium alloy powder contains 62% of Al and the balance of Mg; and / or,

[0082] The molybdenum-iron powder contains 60% of Mo and the balance of Fe; and / or,

[0083] The silicon-manganese alloy powder contains 64% of Mn, 27% of Si, and the balance of Fe.

[0084] In some embodiments of the present application, the metal powder raw material is composed of the following raw materials in percentage of the mass of the metal powder raw material: 1.8%-2.2% of tungsten-iron powder, 20%-24% of low-carbon chromium-iron powder, 1.8%-2.2% of boron carbide powder, 1.5%-2% of silicon-iron powder, 4.5%-5.2% of nickel powder, 0.2%-0.3% of aluminum-magnesium alloy powder, 3.5%-4.5% of molybdenum-iron powder, 0.2%-0.3% of silicon-manganese alloy powder, and the balance of iron powder.

[0085] In some embodiments of the present application, the particle size of the metal powder raw material is not greater than 250 um.

[0086] The particle size of the metal powder raw material can be adjusted by sieving.

[0087] In a third aspect, the embodiments of the present application provide a surfacing method, which is performed by the surfacing repair self-protection flux-cored wire according to any one of the first aspect or the method for preparing the surfacing repair self-protection flux-cored wire according to any one of the second aspect,

[0088] The surfacing voltage is 32-34 V,

[0089] The surfacing current is 300-350 A,

[0090] The surfacing speed is 30-40 cm / min,

[0091] The dry elongation is 18-22 mm,

[0092] The post-weld state is natural air cooling.

[0093] It is easy to understand that the surfacing implementation conditions described above can make the surfacing layer obtained by surfacing have good performance.

[0094] The surfacing method is based on the surfacing repair self-protection flux-cored wire according to any one of the first aspect or the method for preparing the surfacing repair self-protection flux-cored wire according to any one of the second aspect, and the specific implementation of the surfacing method can refer to the above embodiments and the common knowledge in the art. Since the surfacing method adopts part or all of the technical solutions of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, and thus will not be described here one by one.

[0095] The present application will be further described in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. The experimental methods not specified in the following examples are usually determined according to the industry standards. If there is no corresponding industry standard, the general international standards, conventional conditions, or the conditions suggested by the manufacturers are used.

[0096] Example 1

[0097] The present embodiment provides a surfacing repair self-protection flux-cored wire, wherein the flux of the surfacing repair self-protection flux-cored wire comprises the following components:

[0098] The flux of the surfacing repair self-shielded flux-cored wire is composed of 1.8% tungsten iron powder, 20% low-carbon chromium iron powder, 1.8% boron carbide powder, 1.5% silicon iron powder, 4.5% nickel powder, 0.2% aluminum-magnesium alloy powder, 3.5% molybdenum iron powder, 0.2% silicon-manganese alloy powder, and the balance is iron powder, in terms of mass percentage of the flux of the surfacing repair self-shielded flux-cored wire.

[0099] The steel strip of the surfacing repair self-shielded flux-cored wire is a cold-rolled low-carbon steel strip with a size of 0.3mm*14mm, and the composition of the steel strip is 0.1% C, 0.5% Mn, 0.02% P, 0.003% S, 0.05% Si, and the balance is Fe, in terms of mass percentage of the steel strip.

[0100] The filling rate of the surfacing repair self-shielded flux-cored wire is 45%.

[0101] The content of W in the tungsten iron powder is 75%, and the balance is Fe,

[0102] The content of C in the low-carbon chromium iron powder is 0.25%, the content of chromium is 60%, and the balance is Fe,

[0103] The content of Si in the silicon iron powder is 85%, and the balance is Fe,

[0104] The content of Al in the aluminum-magnesium alloy powder is 62%, and the balance is Mg,

[0105] The content of Mo in the molybdenum iron powder is 60%, and the balance is Fe,

[0106] The content of Mn in the silicon-manganese alloy powder is 64%, the content of Si is 27%, and the balance is Fe.

[0107] Example 2

[0108] The surfacing repair self-shielded flux-cored wire provided in the embodiment includes the following components in the flux of the surfacing repair self-shielded flux-cored wire:

[0109] The flux of the surfacing repair self-shielded flux-cored wire is composed of 2.2% tungsten iron powder, 24% low-carbon chromium iron powder, 2.2% boron carbide powder, 2% silicon iron powder, 5.2% nickel powder, 0.3% aluminum-magnesium alloy powder, 4.5% molybdenum iron powder, 0.3% silicon-manganese alloy powder, and the balance is iron powder, in terms of mass percentage of the flux of the surfacing repair self-shielded flux-cored wire.

[0110] The steel strip of the surfacing repair self-shielded flux-cored wire is a cold-rolled low-carbon steel strip with a size of 0.3mm*14mm, and the composition of the steel strip includes, in mass percentage, 0.1% of C, 0.5% of Mn, 0.02% of P, 0.003% of S, and 0.05% of Si, with the balance being Fe.

[0111] The filling rate of the surfacing repair self-shielded flux-cored wire is 45%.

[0112] The tungsten-iron powder contains 75% of W, with the balance being Fe.

[0113] The low-carbon chromium-iron powder contains 0.25% of C and 60% of Cr, with the balance being Fe.

[0114] The silicon-iron powder contains 85% of Si, with the balance being Fe.

[0115] The aluminum-magnesium alloy powder contains 62% of Al, with the balance being Mg.

[0116] The molybdenum-iron powder contains 60% of Mo, with the balance being Fe.

[0117] The silicon-manganese alloy powder contains 64% of Mn and 27% of Si, with the balance being Fe.

[0118] Example 3

[0119] The surfacing repair self-shielded flux-cored wire provided in this example includes a flux composed of the following components:

[0120] The flux of the surfacing repair self-shielded flux-cored wire is composed of, in mass percentage, 2% of tungsten-iron powder, 22% of low-carbon chromium-iron powder, 2% of boron carbide powder, 1.8% of silicon-iron powder, 5% of nickel powder, 0.25% of aluminum-magnesium alloy powder, 4% of molybdenum-iron powder, 0.25% of silicon-manganese alloy powder, and the balance being iron powder.

[0121] The steel strip of the surfacing repair self-shielded flux-cored wire is a cold-rolled low-carbon steel strip with a size of 0.3mm*14mm, and the composition of the steel strip includes, in mass percentage, 0.1% of C, 0.5% of Mn, 0.02% of P, 0.003% of S, and 0.05% of Si, with the balance being Fe.

[0122] The filling rate of the surfacing repair self-shielded flux-cored wire is 45%.

[0123] The tungsten-iron powder contains 75% of W, with the balance being Fe.

[0124] The content of C in the low-carbon chromium iron powder is 0.25%, the content of chromium is 60%, and the balance is Fe,

[0125] The content of Si in the silicon iron powder is 85%, and the balance is Fe,

[0126] The content of Al in the aluminum magnesium alloy powder is 62%, and the balance is Mg,

[0127] The content of Mo in the molybdenum iron powder is 60%, and the balance is Fe,

[0128] The content of Mn in the silicon manganese alloy powder is 64%, the content of Si is 27%, and the balance is Fe.

[0129] Comparative Example 1

[0130] The present embodiment provides a self-protection cored wire for surfacing repair, the flux of the self-protection cored wire for surfacing repair comprises the following components:

[0131] The flux of the self-protection cored wire for surfacing repair is composed of the following raw materials in mass percentage: 2% of tungsten iron powder, 22% of low-carbon chromium iron powder, 2% of boron carbide powder, 4％ Silicon iron powder, 8％ Nickel powder, 0.25% of aluminum magnesium alloy powder, 6％ Molybdenum iron powder, 1％ Silicon manganese alloy powder, and the balance is iron powder.

[0132] The steel strip of the self-protection cored wire for surfacing repair is a cold-rolled low-carbon steel strip with a size of 0.3mm*14mm, and the composition elements of the steel strip are 0.1% of C, 0.5% of Mn, 0.02% of P, 0.003% of S, 0.05% of Si, and the balance is Fe in mass percentage.

[0133] The filling rate of the self-protection cored wire for surfacing repair is 45%.

[0134] The content of W in the tungsten iron powder is 75%, and the balance is Fe,

[0135] The content of C in the low-carbon chromium iron powder is 0.25%, the content of chromium is 60%, and the balance is Fe,

[0136] The content of Si in the silicon iron powder is 85%, and the balance is Fe,

[0137] The content of Al in the aluminum magnesium alloy powder is 62%, and the balance is Mg,

[0138] The content of Mo in the molybdenum iron powder is 60%, and the balance is Fe,

[0139] The content of Mn in the silicon-manganese alloy powder is 64%, the content of Si is 27%, and the balance is Fe.

[0140] Comparative Example 2

[0141] The present embodiment provides a self-protection cored wire for surfacing repair, the flux of the self-protection cored wire for surfacing repair comprises the following components:

[0142] The flux of the self-protection cored wire for surfacing repair is composed of the following raw materials in mass percentage: 4％ 75% tungsten-iron powder, 30％ 2% low-carbon chromium-iron powder, 2% boron carbide powder, 4％ 1% silicon-iron powder, 8％ 1% nickel powder, 0.65％ 1% aluminum-magnesium alloy powder, 6％ 0.2% molybdenum-iron powder, 0.2% silicon-manganese alloy powder, and the balance of iron powder.

[0143] The steel strip of the self-protection cored wire for surfacing repair is a cold-rolled low-carbon steel strip with a size of 0.3mm*14mm, and the composition of the steel strip is 0.1% C, 0.5% Mn, 0.02% P, 0.003% S, 0.05% Si, and the balance of Fe in mass percentage.

[0144] The filling rate of the self-protection cored wire for surfacing repair is 43%.

[0145] The content of W in the tungsten-iron powder is 75%, and the balance is Fe,

[0146] The content of C in the low-carbon chromium-iron powder is 0.25%, the content of chromium is 60%, and the balance is Fe,

[0147] The content of Si in the silicon-iron powder is 85%, and the balance is Fe,

[0148] The content of Al in the aluminum-magnesium alloy powder is 62%, and the balance is Mg,

[0149] The content of Mo in the molybdenum-iron powder is 60%, and the balance is Fe,

[0150] The content of Mn in the silicon-manganese alloy powder is 64%, the content of Si is 27%, and the balance is Fe.

[0151] Related experiments and effect data:

[0152] After surface grinding, cleaning and rust removal of the 45# steel plate, the bottom plate was prepared for surfacing. The surfacing repair self-shielded flux-cored wire provided in Example 1 was continuously longitudinally surfacing along one end of the bottom plate. After cooling, the second layer was surfacing. Each layer was surfacing 8-10 passes. The thickness of the final surfacing layer was about 5 millimeters. The area was about 50 square centimeters. The surfacing wear-resistant test sample plate was obtained. The surfacing layer of the surfacing wear-resistant test sample plate was tested for hardness and wear resistance. Subsequently, the surfacing repair self-shielded flux-cored wire provided in Example 2, Example 3, Comparative Example 1, Comparative Example 2 was used to replace the surfacing repair self-shielded flux-cored wire provided in Example 1 to prepare the surfacing layer of the surfacing wear-resistant test sample plate. The surfacing layer of the surfacing wear-resistant test sample plate obtained was tested for hardness and wear resistance.

[0153] After surface grinding, cleaning and rust removal of the 45# steel plate, the bottom plate was prepared for surfacing. The surfacing repair self-shielded flux-cored wire provided in Example 1 was continuously longitudinally surfacing along one end of the bottom plate. After cooling, the second layer was surfacing. Each layer was surfacing 8-10 passes. The thickness of the final surfacing layer was about 5 millimeters. The area was about 50 square centimeters. The surfacing wear-resistant test sample plate was obtained. The surfacing layer of the surfacing wear-resistant test sample plate was tested for hardness and wear resistance. Subsequently, the surfacing repair self-shielded flux-cored wire provided in Example 2, Example 3, Comparative Example 1, Comparative Example 2 was used to replace the surfacing repair self-shielded flux-cored wire provided in Example 1 to prepare the surfacing layer of the surfacing wear-resistant test sample plate. The surfacing layer of the surfacing wear-resistant test sample plate obtained was tested for hardness and wear resistance.

[0154] The above surfacing processes were implemented with the following parameters: surfacing voltage was 34V, surfacing current was 300A, surfacing speed was 35cm / min, dry elongation was 20mm, and post-welding state was natural air cooling.

[0155] The hardness test specifically included Rockwell hardness test and Vickers hardness test. The Rockwell hardness test was performed by TH-320 Rockwell hardness tester,

[0156] The Vickers hardness test was performed by the following way:

[0157] After wire cutting, grinding and polishing of the surfacing wear-resistant test sample plate, the load was 300 grams, the loading time was 15 seconds, the interface between the substrate and the surfacing layer was taken as the first point, and the Vickers hardness of the cross section was measured every 300 microns.

[0158] The hardness test data is shown in Table 1:

[0159] Table 1: Hardness test data of surfacing wear-resistant test sample plates corresponding to Examples 1-5

[0160] HRC HV 0.3 ]] Example 1 60.08 1072.5 Example 2 60.91 1223.2 Example 3 60.44 1147.1 Comparative Example 1 36.21 518.5 Comparative Example 2 62.26 1165.32

[0161] As can be seen from Table 1, the Rockwell hardness and Vickers hardness values of the surfacing wear-resistant test samples corresponding to Examples 1-3 and Comparative Example 2 are higher, while the hardness values of the surfacing wear-resistant test sample corresponding to Comparative Example 1 are lower.

[0162] The wear resistance test was performed as follows:

[0163] The surfacing layers were subjected to rotary dry friction at room temperature, with a load of 1 kg, a wear time of 20 minutes, a wear radius of 2 mm, a rotation speed of 1300 rpm, and wear data were collected.

[0164] The wear data are shown in Table 2.

[0165] Table 2 Wear data of the surfacing wear-resistant test samples corresponding to Examples 1-5

[0166] Friction coefficient Wear volume (mm 3 )]]> Wear rate (mm 3 / Nm) Example 1 0.48 10.02 x 10 -3 ]] 3.41 x 10 -6 ]]> Example 2 0.51 12.08 x 10 -3 ]] 4.15 x 10 -6 ]] Example 3 0.49 11.26 x 10 -3 ]] 3.86 x 10 -6 ]] Comparative Example 1 0.43 154.3 x 10 -3 ]]> 52.9 x 10 -6 ]]> Comparative Example 2 0.50 69.32 x 10 -3 ]]> 23.49 x 10 -6 ]]

[0167] As can be seen from Table 2, the wear resistance of the surfacing wear-resistant test samples corresponding to Examples 1-3 is very good, with a very low wear rate. The wear resistance of Comparative Examples 1-2 is much lower than that of Examples 1-3, and the wear resistance of Comparative Example 1 is the lowest.

[0168] The cracking test was performed as follows:

[0169] After the surfacing cracking test sample was ground and polished, a "cross" indentation was formed on the surface under a microhardness tester with a load of 1 kg for 30 seconds, and whether there was an obvious crack extending was observed under a scanning electron microscope.

[0170] No obvious crack extending was observed in the surfacing cracking test samples corresponding to Examples 1-3 and Comparative Example 1. This indicates that the surfacing layers of the surfacing cracking test samples corresponding to Examples 1-3 and Comparative Example 1 have good cracking resistance. The surfacing layer of the surfacing cracking test sample corresponding to Comparative Example 2 is poorly deslagged, with a very poor appearance, and cannot be used for this test and has no practical value. The appearance of the surfacing cracking test sample corresponding to Comparative Example 2 is shown in Figure 3 .

[0171] Overall, the weld overlays formed in Examples 1-3 all exhibited good hardness, wear resistance, and crack resistance. Comparative Example 1, however, showed poor hardness and wear resistance, while its crack resistance was acceptable. This may be because molybdenum and nickel elements improve the toughness of the weld overlay and reduce cracking by refining the ferrite structure. However, excessive use or an imbalance in the proportion of molybdenum and nickel with other strengthening elements may inhibit the bonding of these elements and hinder the diffusion of carbon and boron, thus rapidly reducing the amount of hard phase in the weld overlay. Consequently, the hardness and wear resistance of the weld overlay also decrease significantly as the hard phase decreases. Furthermore, an excessive silicon-manganese ratio caused the grains of the weld overlay to become coarse, also negatively impacting performance. Comparative Example 2 exhibits better hardness and wear resistance, but poorer crack resistance. This may be because, compared to Comparative Example 1, the proportion of reinforcing elements chromium and tungsten was increased to increase the content of hard phases such as tungsten carbide or chromium carbide in the weld overlay to maintain hardness and wear resistance. However, more deoxidizing elements are required to maintain deoxidation and slag removal. But the light metals such as aluminum and magnesium used for deoxidation will rapidly reduce the toughness of the weld overlay, making cracking very easy to occur. Furthermore, excessive aluminum and magnesium will severely reduce the surface condition of the weld overlay, and even result in an incomplete weld overlay surface appearance.

[0172] Furthermore, during the welding process using the self-shielded flux-cored welding wires provided in Examples 1-3, the generated fumes were minimal, and there was no arc interruption. Visual observation of the final weld overlay revealed very small weld spatter particles, with no visible cracks or obvious slag adhesion. The slag initially formed a dark black color and uniformly covered the weld overlay surface, then detached itself upon cooling. Ultimately, the entire weld overlay surface exhibited a faint reddish hue, appearing smooth, bright, and aesthetically pleasing—an acceptable morphology for practical applications. A photograph of the weld overlay wear resistance test specimen corresponding to Example 1 is shown below. Figure 1 As shown, by Figure 1 It is evident that the surface morphology of the weld overlay is good. After cutting, grinding, etching, and cleaning the weld overlay wear resistance test specimen corresponding to Example 1, the cross-section of the weld overlay was observed, as shown... Figure 2 As shown, the weld overlay thickness is approximately 4-5 mm. Scanning electron microscopy reveals a distinct planar transition layer between the weld overlay and the base plate, with a thickness of approximately 15 micrometers, indicating that the weld overlay is well bonded to the substrate and exhibits a stable metallurgical bond.

[0173] Various embodiments of the application can exist in a range of forms; it should be understood that a range recitation is given only as a convenience and brevity, and should not be construed as a rigid limitation on the scope of the application; thus, it should be considered that the recitation of a range is specifically disclosed as disclosing all possible sub-ranges contained therein, as well as individual numerical values within that range. For example, a range recitation of 1 to 6 should be considered to have specifically disclosed the sub-ranges like 1 to 3, 1 to 4, 1 to 5, 2 to 4, 2 to 6, 3 to 6, etc., as well as the individual numbers 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integral) within the indicated range.

[0174] In this application, the use of directional adjectives such as "upper" and "lower" are specific to the orientation of the drawing figures unless otherwise indicated. In addition, in the description of the application, the terms "including", "containing" and the like are meant to be open-ended and non-limiting. Also, the terms "including", "containing" or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article or apparatus. An element proceeded by "comprises a", "has", "includes" or "contains", without more, does not, without more, exclude the presence of additional identical elements following the comma. In this document, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual relationship or order between such entities or actions. In this document, the term "and / or" is used to describe a relationship between two or more objects, and is meant to mean that any one of the objects, or any combination of two or more of the objects, can be present. For example, the phrase "A and / or B" is meant to mean that only A, only B, or both A and B can be present. For combinations having more than two objects, such as "A, B, and / or C", the intended meaning is that any of the combinations of A, B, and C can be present, including only A, only B, only C, A and B, A and C, B and C, or A and B and C. In this document, the term "at least one" is used to describe a relationship between two or more objects, and is meant to mean that any one of the objects, or any combination of two or more of the objects, can be present. For example, the phrase "at least one of A, B, and C" is meant to mean that A, B, C, A and B, A and C, B and C, or A and B and C can be present. In this document, the term "plurality" is used to describe a relationship between two or more objects, and is meant to mean that any one of the objects, or any combination of two or more of the objects, can be present. For example, the phrase "a plurality of A, B, and C" is meant to mean that A, B, C, A and B, A and C, B and C, or A and B and C can be present.

[0175] The foregoing detailed description of the application has been presented for purposes of illustration and description. Various modifications and changes can be made to these embodiments without departing from the spirit and scope of the application. It is intended that the scope of the application should not be limited by the particular representative embodiments described above. Rather, the general scope of the application is to be determined by the appended claims and their equivalents.

Claims

1. A self-shielded flux-cored welding wire for weld overlay repair, characterized in that, The flux of the self-shielded flux-cored wire for weld overlay repair, by mass percentage, comprises the following elements: 0.4%~0.6% C, 1.31%~1.72% B, 1.32%~1.78% Si, 0.12%~0.19% Mn, 0.12%~0.18% Al, 0.08%~0.12% Mg, 12.0%~14.4% Cr, 2.1%~2.7% Mo, 0.56%~0.75% W, 4.5%~5.4% Ni, with the balance being Fe; the flux of the self-shielded flux-cored wire for weld overlay repair includes the following components: ferrotungsten powder, low-carbon ferrochrome powder, boron carbide powder, ferrosilicon powder, nickel powder, aluminum-magnesium alloy powder, ferromolybdenum powder, silicon-manganese alloy powder, and iron powder.

2. The self-shielded flux-cored welding wire for weld overlay repair according to claim 1, characterized in that, The ferrotungsten powder contains 75% W and the balance is Fe; and / or, The low-carbon ferrochrome powder contains 0.15% to 0.5% carbon, 60% chromium, and the balance is Fe; and / or, The ferrosilicon powder contains 85% Si and the balance is Fe; and / or, The aluminum-magnesium alloy powder contains 62% Al and the balance is Mg; and / or, The ferromolybdenum powder contains 60% Mo and the balance is Fe; and / or, The silicon-manganese alloy powder contains 64% Mn, 27% Si, and the balance is Fe.

3. The self-shielded flux-cored welding wire for weld overlay repair according to claim 1, characterized in that, The flux of the self-shielded flux-cored wire for weld overlay repair, by weight percentage, is composed of the following raw materials: 1.8%~2.2% ferrotungsten powder, 20%~24% low-carbon ferrochrome powder, 1.8%~2.2% boron carbide powder, 1.5%~2% ferrosilicon powder, 4.5%~5.2% nickel powder, 0.2%~0.3% aluminum-magnesium alloy powder, 3.5%~4.5% ferromolybdenum powder, 0.2%~0.3% silicon-manganese alloy powder, and the balance being iron powder.

4. A method for preparing a self-shielded flux-cored welding wire for weld overlay repair, characterized in that, The preparation method of the self-shielded flux-cored welding wire for weld overlay repair includes the following steps: Provide metal powder raw materials: mix ferrotungsten powder, low-carbon ferrochrome powder, boron carbide powder, ferrosilicon powder, nickel powder, aluminum-magnesium alloy powder, ferromolybdenum powder, ferrosilicon manganese alloy powder, and iron powder; Using the aforementioned metal powder raw material as flux, a flux-cored welding wire is prepared to obtain a self-shielded flux-cored welding wire for weld overlay repair. The metal powder raw material, by mass percentage, is composed of the following elements: 0.4%~0.6% C, 1.31%~1.72% B, 1.32%~1.78% Si, 0.12%~0.19% Mn, 0.12%~0.18% Al, 0.08%~0.12% Mg, 12.0%~14.4% Cr, 2.1%~2.7% Mo, 0.56%~0.75% W, 4.5%~5.4% Ni, with the balance being Fe.

5. The method for preparing the self-shielded flux-cored welding wire for weld overlay repair according to claim 4, characterized in that, The ferrotungsten powder contains 75% W and the balance is Fe; and / or, The low-carbon ferrochrome powder contains 0.15% to 0.5% carbon, 60% chromium, and the balance is Fe; and / or, The ferrosilicon powder contains 85% Si and the balance is Fe; and / or, The aluminum-magnesium alloy powder contains 62% Al and the balance is Mg; and / or, The ferromolybdenum powder contains 60% Mo and the balance is Fe; and / or, The silicon-manganese alloy powder contains 64% Mn, 27% Si, and the balance is Fe.

6. The method for preparing the self-shielded flux-cored welding wire for weld overlay repair according to claim 4, characterized in that, Based on the mass percentage of the metal powder raw material, the metal powder raw material is composed of the following raw materials: 1.8%~2.2% ferrotungsten powder, 20%~24% low-carbon ferrochrome powder, 1.8%~2.2% boron carbide powder, 1.5%~2% ferrosilicon powder, 4.5%~5.2% nickel powder, 0.2%~0.3% aluminum-magnesium alloy powder, 3.5%~4.5% ferromolybdenum powder, 0.2%~0.3% silicon-manganese alloy powder, and the balance being iron powder.

7. The method for preparing the self-shielded flux-cored welding wire for weld overlay repair according to claim 4, characterized in that, The particle size of the metal powder raw material is no greater than 250 μm.

8. A method for overlaying welding, characterized in that, The welding method is performed using the self-shielded flux-cored wire for welding repair as described in any one of claims 1 to 3, or using the self-shielded flux-cored wire for welding repair prepared by the method described in any one of claims 4 to 7. The welding voltage is 32~34V. The welding current is 300~350A. The welding speed is 30~40cm / min. The elongation is 18~22mm. The post-weld condition is natural air cooling.

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