Wide-temperature-range iron-based hardfacing self-protection flux-cored wire capable of resisting 650 DEG C and below

Abstract

The invention relates to a wide-temperature-range iron-based hardfacing self-protection flux-cored wire capable of resisting 650 DEG C and below. The flux-cored wire comprises a cold-rolled steel strip outer skin and flux-cored powder wrapped in the cold-rolled steel strip outer skin. The flux core powder comprises, by mass, 40%-60% of high-carbon ferrochrome, 1%-6% of graphite, 10%-21% of ferromolybdenum, 5%-13% of ferroniobium, 1%-6% of ferrovanadium, 3%-8% of ferrotungsten, 0-3% of ferro-silicon-manganese, 3%-8% of rutile, 1%-4% of sodium fluosilicate, 0-3% of potassium feldspar and 1%-3% of fluorite powder. The problem that the self-protection capability is not coordinated with the high-temperature hardness and the wear resistance in the prior art is solved. According to the wide-temperature-range iron-based hardfacing self-protection flux-cored wire capable of resisting 650 DEG C and below, the use of precious metal can be reduced, and the manufacturing cost is effectively reduced. Through multi-component strengthening, the target that the room-temperature hardness is not lower than 60 HRC can be achieved, and the average hardness in the high-temperature environment of 650 DEG C is kept within the range of 42-53 HRC. In addition, the technical blank that the iron-based hardfacing coating is used for surface protection in the medium and low temperature environment of 350-650 DEG C is filled.

Description

Technical Field

[0001] The invention relates to the field of welding materials, and in particular to an iron-based wear-resistant surfacing self-protective flux-cored welding wire that can withstand a wide temperature range of 650°C or below. Background Art

[0002] With the rapid development of industrial technology, the demand for high-quality steel is increasing, resulting in many key equipment parts in the iron and steel metallurgical industry facing increasingly harsh working environments, such as the central throat of the blast furnace in the steel plant, the distribution chute, the screen plate, the material bell, the continuous annealing roller, and the ghost teeth and grate plates of the sintering plant, which often need to withstand high temperature wear. Surface surfacing protection of these workpieces is an effective means to improve their service life. However, under high temperature and high wear conditions, traditional wear-resistant surfacing materials often cannot meet the requirements, and there are problems such as decreased hardness and insufficient wear resistance, resulting in the use efficiency and service life of parts not being effectively improved. For example, the traditional high-chromium cast iron system wear-resistant surfacing coating can usually only serve in a low temperature environment not exceeding 350°C, and cannot meet the use requirements for medium temperature (350-650°C) and above. High temperature environment. Therefore, it is of great practical significance to develop an iron-based surfacing flux-cored wire material that can maintain excellent wear resistance in a wide temperature range.

[0003] Self-shielded flux-cored welding wire is a special flux-cored welding wire developed on the basis of ordinary flux-cored welding wire. During welding, no external shielding gas is needed to protect the welding area. Instead, the slag and gas released when the flux powder inside the welding wire melts are used to cover the liquid metal and form a gas shielding layer near the surface of the molten pool to isolate the outside air. This self-shielded flux-cored welding wire is very convenient for field welding and welding without a shielding gas source. It is low in cost, easy to use and flexible. It also has significant advantages for online repair or surface modification of complex structural parts.

[0004] At present, in order to make the self-shielded flux-cored welding wire obtain good anti-porosity and process performance, the usual design idea is to add a large amount of strong deoxidizers and denitrifiers, such as aluminum-magnesium alloys, titanium iron, etc., into the flux core. However, this can easily cause the mechanical properties of the deposited metal, especially the impact toughness, to be poor, and it cannot be used for important structures. Another design idea is that in order to reduce the content of deoxidizers and denitrifiers, alkaline slag is often used. However, due to the high proportion of alkaline components such as fluorides and carbonates with low density and fine particles in the powder, it is difficult to evenly distribute them in the flux core after mixing with the required ferroalloy powder. At the same time, it also affects the fluidity of the powder, resulting in poor welding process performance, reduced anti-porosity, increased spatter, and difficulty in slag removal. Therefore, the application of these two types of self-shielded flux-cored welding wires is limited.

[0005] Patent CN 1152490A discloses a high-basicity self-shielded flux-cored welding wire, the flux-cored welding wire composition includes (by weight percentage): pre-treated mixed powder 40-60% (including fluorite-based fluoride salt 50-80%, marble-based carbonate 20-50%, oxide 0-15%), ferromanganese 0-8%, ferrosilicon 0-3%, aluminum-magnesium alloy 16-36%, nickel powder 0-4%, the balance is iron powder, and the filling rate is 15-35%. The self-shielded flux-cored welding wire has the ability to resist rust and cracking, but does not have the ability to resist high temperature wear.

[0006] Patent CN 112222682A discloses a high-fluorine alkaline powder, a preparation method and a self-shielding flux-cored welding wire, wherein the flux-cored welding wire comprises (by mass percentage): 5-10% marble, 14-18% fluorite, 18-22% barium fluoride, 2-4% lithium fluoride, 1-3% rare earth fluoride, 3-6% quartz sand, 5-9% rutile, 4-8% magnesia sand, 2-4% zircon sand, 3-6% iron sand, 4-6% ferrotitanium, 2-4% ferromanganese, 4-6% electrolytic manganese, 3-6% nickel powder and 2-4% ferrosilicon. The self-shielding flux-cored welding wire solves the problem of excessive oxidation of weld metal and overcomes the disadvantage of poor fluidity of high alkaline powder by pelletization. However, in terms of applicability, due to the lack of high temperature resistant and wear resistant metal elements, it cannot be used in the field of high temperature wear resistance.

[0007] Patent CN 1304161C discloses a high-hardness, high-wear-resistant self-protective metal core cladding wire, the metal core composition of which includes (by mass percentage): 64-77% chromium carbide, 4-7% 75# ferrosilicon, 5-10% metallic manganese, 1-3% aluminum-magnesium alloy, 2-5% ferroboron, 2-6% ferrotitanium, 1-5% ferroniobium, and 1-8% ferrovanadium. The protection mechanism of the self-protective metal core cladding wire for the welding molten pool mainly includes the gas protection mechanism formed by manganese vapor, the deoxidation protection mechanism of silicon + manganese + aluminum + magnesium, the denitrification-fixation mechanism of aluminum + boron + titanium + niobium, and the molten pool self-protection mechanism. Although the invention adds a large amount of chromium carbide to improve hardness and wear resistance, the strong deoxidation and denitrification agents are relatively small, the self-protection effect may be lacking, and it does not show the ability to resist high-temperature wear. Summary of the invention

[0008] The purpose of the present invention is to provide an iron-based wear-resistant surfacing self-protecting flux-cored welding wire with a wide temperature range of 650°C and below, so as to overcome the problem of the incompatibility between the self-protection ability and the high temperature hardness and wear resistance in the prior art.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] The invention discloses an iron-based wear-resistant surfacing self-protected flux-cored welding wire capable of resisting a wide temperature range of 650°C or below, comprising a cold-rolled steel strip outer skin and a flux-cored powder wrapped therein, wherein the flux-cored powder comprises the following components by mass percentage: 40% to 60% high-carbon ferrochromium, 1% to 6% graphite, 10% to 21% ferromolybdenum, 5% to 13% ferroniobium, 1% to 6% ferrovanadium, 3% to 8% ferrotungsten, 0% to 3% ferrosiliconmanganese, 3% to 8% rutile, 1% to 4% sodium fluorosilicate, 0% to 3% potassium feldspar and 1% to 3% fluorite powder.

[0011] The flux core powder materials of the present invention are all commercially available raw materials. The main components, powder particle sizes and functions of each raw material in the welding wire are as follows:

[0012] The high carbon ferrochrome contains 7% to 9% C and ≥60% Cr; the particle size is 60 to 325 meshes; C and Cr are transitioned to the cladding layer to form a hard carbide phase, which plays a major role in wear resistance.

[0013] The ferromolybdenum contains ≥60% Mo, with a particle size of 80-200 meshes, and the Mo element is transferred to the cladding layer to improve its hardenability, wear resistance and red hardness. The ferroniobium contains ≥50% Nb, with a particle size of 60-200 meshes, and the Nb element is transferred to the cladding layer to refine the grains and improve the high temperature hardness, wear resistance and oxidation resistance of the cladding layer.

[0014] The ferrovanadium contains 40% to 55% of V, and the particle size is 60 to 200 meshes; the V element is transferred to the surfacing layer to improve the heat resistance and wear resistance of the surfacing layer. The ferrotungsten contains 75% to 80% of W, and the particle size is 80 to 200 meshes; the W element is transferred to the surfacing layer to improve the high temperature wear resistance of the surfacing layer.

[0015] The silicon-manganese iron contains 65% to 72% Mn and 17% to 20% Si; the particle size is 60 to 325 meshes; the Si and Mn elements are transferred to the cladding layer to achieve joint deoxidation and desulfurization, reduce the tendency of thermal cracking, and can also play a role in solid solution strengthening and improving heat resistance. The graphite contains ≥98% C; the particle size is 60 to 120 meshes; the C element is transferred to the cladding layer, which is the basic element for forming Fe-C binary alloy, and forms hard carbides with other metals to improve the wear resistance of the cladding layer. The rutile contains ≥92% TiO2; the particle size is 60 to 325 meshes; it has a good protective effect on overheated droplets, reduces metal evaporation during the droplet transition process, and at the same time plays a slag-making role, stabilizes the welding arc, and improves the welding process performance.

[0016] The sodium fluorosilicate has a purity of ≥99% and a particle size of 60-325 meshes. It decomposes and generates gas during the melting process of the welding wire to protect overheated molten droplets, and at the same time fully deoxidizes and improves the stability of the welding arc.

[0017] The potassium feldspar contains 9% to 16% of K2O, 65% to 70% of SiO2 and ≥16% of Al2O3; the particle size is 60 to 325 meshes; the arc stabilizer has the function of stabilizing the electric arc, increasing the viscosity of the slag, protecting the overheated molten droplets, and reducing the amount of dust generated.

[0018] The fluorite contains ≥96% of CaF2 and has a particle size of 60-325 meshes. It decomposes and generates gas during the melting process of the welding wire to protect the overheated molten droplets from oxidation.

[0019] The cold-rolled steel strip is H08A, and the dimensions of the steel strip are: 15-20 mm in width and 0.35-0.6 mm in thickness.

[0020] A method for manufacturing a self-shielded flux-cored welding wire with a wide temperature range of 650°C or below, comprising the following steps:

[0021] 1) The rutile and fluorite powders are subjected to a high temperature baking treatment at 550-800°C to remove the crystal water substances;

[0022] 2) drying the sodium fluorosilicate and potassium feldspar at a medium to low temperature of 300 to 500° C. to remove moisture;

[0023] 3) subjecting high carbon ferrochrome, graphite, ferromolybdenum, ferroniobium, ferrovanadium, ferrotungsten and ferrosilicon manganese to low temperature drying at 200-300°C to remove moisture;

[0024] 4) Mechanically mixing the raw materials after the above treatment according to mass percentage to obtain a core powder material;

[0025] 5) On a flux-cored welding wire production line, the flux-cored powder material of step 4) is uniformly wrapped with a cold-rolled steel strip, and is rolled and drawn into a flux-cored welding wire with a diameter of 2.4 to 3.2 mm, and the filling rate (the percentage of the flux-cored powder material in the total weight of the flux-cored welding wire) is controlled at 35% to 50%.

[0026] After at least 2 layers of cladding, the surface cladding metal contains the following alloy elements in percentage by mass: 4% to 6% C, 0.3% to 1.0% Si, 0.2% to 0.9% Mn, 18% to 24% Cr, 4% to 7% Mo, 2% to 5% Nb, 0.8% to 1.6% V, 2.5% to 6.5% W, and the remainder is Fe.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1) The present invention provides a self-shielded flux-cored welding wire with a wide temperature range of 650°C and below, which can reduce the use of precious metals and effectively reduce manufacturing costs. The room temperature hardness of not less than 60HRC can be achieved through multi-component strengthening, and the average hardness in a high temperature environment of 650°C is maintained in the range of 42 to 53HRC. In addition, the present invention fills the technical gap of surface protection by iron-based wear-resistant surfacing coatings in medium and low temperature environments between 350 and 650°C.

[0029] 2) Rutile, sodium fluorosilicate, potassium feldspar and fluorite powder are added to the self-shielded flux-cored welding wire of the present invention, which will form high-basicity slag through metallurgical reaction during the surfacing process, effectively weakening the oxidation effect of high-temperature air on liquid metal, and forming a variety of fluoride gases covering the surface of liquid slag to isolate external air from invading the molten pool. Thus, a double protection measure is formed near the surface of the molten pool. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the microstructure of the cladding metal in Example 1 of the present invention. DETAILED DESCRIPTION

[0031] The present invention is described in detail below with reference to actual tooling conditions, but the present invention is not limited to these implementation cases. Unless otherwise specified, the raw materials involved in the present invention are purchased through commercial channels.

[0032] Embodiment 1:

[0033] The invention discloses an iron-based wear-resistant surfacing self-protected flux-cored welding wire capable of resisting a wide temperature range of 650°C or below, comprising a cold-rolled steel strip outer skin and a flux core powder wrapped therein, wherein the flux core is composed of the following raw materials in percentage by mass: 41% high-carbon ferrochromium, 5.9% graphite, 10.4% ferromolybdenum, 12.7% ferroniobium, 5.8% ferrovanadium, 7.6% ferrotungsten, 2.8% ferrosiliconmanganese, 7.5% rutile, 1.2% sodium fluorosilicate, 1.2% potassium feldspar and 1.1% fluorite powder.

[0034] Among them, high carbon ferrochromium contains 8.8wt% C, 68wt% Cr, and the powder particle size is 60-325 mesh. Ferromolybdenum contains 64wt% Mo, and the powder particle size is 80-120 mesh. Ferroniobium contains 55wt% Nb, and the powder particle size is 60-180 mesh. Ferrovanadium contains 52wt% V, and the particle size is 80-150 mesh. Ferrotungsten contains 76wt% W, and the particle size is 120-200 mesh. Ferrosilicomanganese contains 68wt% Mn and 19wt% Si, and the powder particle size is 80-240 mesh. Graphite contains 98.5wt% C, and the powder particle size is 60-120 mesh. Rutile contains 93% TiO2, and the particle size is 80-240 mesh. Sodium fluorosilicate has a purity of 99% and a particle size of 60-200 mesh. Potassium feldspar contains 15% K2O, 18% Al2O3 and 65% SiO2, with a particle size of 80 to 200 mesh. Fluorite powder contains 96.5% CaF2, with a particle size of 60 to 180 mesh.

[0035] The cold-rolled steel strip is H08A, and the dimensions of the steel strip are: 16 mm in width and 0.4 mm in thickness.

[0036] The rutile and fluorite powders are baked at high temperature (750°C) to remove their crystal water; sodium fluorosilicate and potassium feldspar are dried at medium and low temperature (500°C) to remove their moisture; high carbon ferrochrome, graphite, ferromolybdenum, ferroniobium, ferrovanadium, ferrotungsten and ferrosilicon manganese are dried at low temperature (250°C) to remove their moisture; the raw materials after the above treatments are mechanically mixed according to mass percentage to obtain a core powder material.

[0037] On the flux-cored welding wire production line, H08A cold-rolled steel strip is wrapped with evenly mixed flux-cored powder, which is then drawn and reduced to produce flux-cored welding wire with a diameter of 2.8 mm and a filling rate of 46%.

[0038] After two layers of open arc surfacing, the main chemical composition of the outer surface of the surfacing layer is 5.4wt% C, 0.85wt% Si, 0.82wt% Mn, 18.6wt% Cr, 4.1wt% Mo, 4.8wt% Nb, 1.58% V, 6.3% W, and the rest is Fe. The average hardness at room temperature is 60.5HRC, and the high temperature hardness at 650℃ is 43HRC. After 30min of high temperature friction and wear at 650℃, the wear loss is 106.3mg.

[0039] Embodiment 2:

[0040] The invention discloses an iron-based wear-resistant surfacing self-protected flux-cored welding wire capable of resisting a wide temperature range of 650°C or below, comprising a cold-rolled steel strip outer skin and a flux core powder wrapped therein, wherein the flux core is composed of the following raw materials in percentage by mass: 45% high-carbon ferrochromium, 5.1% graphite, 12.7% ferromolybdenum, 10.95% ferroniobium, 5.1% ferrovanadium, 6% ferrotungsten, 2.3% ferrosiliconmanganese, 6.2% rutile, 1.9% sodium fluorosilicate, 0.5% potassium feldspar and 1.6% fluorite powder.

[0041] Among them, high carbon ferrochromium contains 8.2wt% C, 67wt% Cr, and the powder particle size is 80-325 mesh. Ferromolybdenum contains 65wt% Mo, and the powder particle size is 80-200 mesh. Ferroniobium contains 51wt% Nb, and the powder particle size is 60-200 mesh. Ferrovanadium contains 46wt% V, and the particle size is 60-180 mesh. Ferrotungsten contains 79wt% W, and the particle size is 120-200 mesh. Ferrosilicomanganese contains 65wt% Mn and 20wt% Si, and the powder particle size is 80-325 mesh. Graphite contains 99wt% C, and the powder particle size is 60-120 mesh. Rutile contains 95% TiO2, and the particle size is 60-240 mesh. Sodium fluorosilicate has a purity of 99% and a particle size of 80-240 mesh. Potassium feldspar contains 10% K2O, 20% Al2O3 and 68% SiO2, with a particle size of 80 to 240 mesh. Fluorite powder contains 97% CaF2, with a particle size of 80 to 325 mesh.

[0042] The cold-rolled steel strip is H08A, and the dimensions of the steel strip are: 20 mm in width and 0.55 mm in thickness.

[0043] The rutile and fluorite powders are baked at high temperature (780°C) to remove their crystal water; sodium fluorosilicate and potassium feldspar are dried at medium and low temperature (450°C) to remove their moisture; high carbon ferrochrome, graphite, ferromolybdenum, ferroniobium, ferrovanadium, ferrotungsten and ferrosilicon manganese are dried at low temperature (230°C) to remove their moisture; the raw materials after the above treatments are mechanically mixed according to mass percentage to obtain a core powder material.

[0044] On the flux-cored welding wire production line, H08A cold-rolled steel strip is wrapped with uniformly mixed flux-cored powder, which is then drawn and reduced to produce flux-cored welding wire with a diameter of 3.2 mm and a filling rate of 50%.

[0045] After two layers of open arc surfacing, the main chemical composition of the outer surface of the surfacing layer is 5.1wt% C, 0.8wt% Si, 0.78wt% Mn, 19wt% Cr, 4.3wt% Mo, 4.6wt% Nb, 1.53% V, 5.8% W, and the rest is Fe. The average hardness at room temperature is 61.3HRC, and the high temperature hardness at 650℃ is 45HRC. After 30min of high temperature friction and wear at 650℃, the wear loss is 63.5mg.

[0046] Embodiment 3:

[0047] The invention discloses an iron-based wear-resistant surfacing self-protected flux-cored welding wire capable of resisting a wide temperature range of 650°C or below, comprising a cold-rolled steel strip outer skin and a flux core powder wrapped therein, wherein the flux core is composed of the following raw materials in percentage by mass: 48% high-carbon ferrochromium, 4.8% graphite, 15.2% ferromolybdenum, 8.5% ferroniobium, 4.5% ferrovanadium, 5% ferrotungsten, 2% ferrosilicomanganese, 5.4% rutile, 3.8% sodium fluorosilicate, 2.5% potassium feldspar and 1.3% fluorite powder.

[0048] Among them, high carbon ferrochromium contains 8.5wt% C, 65wt% Cr, and the powder particle size is 60-200 mesh. Ferromolybdenum contains 67wt% Mo, and the powder particle size is 80-120 mesh. Ferroniobium contains 53wt% Nb, and the powder particle size is 60-200 mesh. Ferrovanadium contains 50wt% V, and the particle size is 80-200 mesh. Ferrotungsten contains 75wt% W, and the particle size is 120-200 mesh. Ferrosilicomanganese contains 67wt% Mn and 20wt% Si, and the powder particle size is 60-200 mesh. Graphite contains 98wt% C, and the powder particle size is 60-120 mesh. Rutile contains 92% TiO2, and the particle size is 80-325 mesh. Sodium fluorosilicate has a purity of 99% and a particle size of 80-200 mesh. Potassium feldspar contains 11% K2O, 18% Al2O3 and 67% SiO2, with a particle size of 120 to 325 mesh. Fluorite powder contains 96% CaF2, with a particle size of 60 to 240 mesh.

[0049] The cold-rolled steel strip is H08A, and the dimensions of the steel strip are: 18 mm in width and 0.5 mm in thickness.

[0050] The rutile and fluorite powders are baked at high temperature (630°C) to remove their crystal water; sodium fluorosilicate and potassium feldspar are dried at medium and low temperature (380°C) to remove their moisture; high carbon ferrochrome, graphite, ferromolybdenum, ferroniobium, ferrovanadium, ferrotungsten and ferrosilicon manganese are dried at low temperature (280°C) to remove their moisture; the raw materials after the above treatments are mechanically mixed according to mass percentage to obtain the core powder material.

[0051] On the flux-cored welding wire production line, H08A cold-rolled steel strip is wrapped with evenly mixed flux-cored powder, which is then drawn and reduced to produce flux-cored welding wire with a diameter of 2.8 mm and a filling rate of 48%.

[0052] After two layers of open arc surfacing, the main chemical composition of the outer surface of the surfacing layer is 4.8wt% C, 0.7wt% Si, 0.6wt% Mn, 20wt% Cr, 4.5wt% Mo, 4.5wt% Nb, 1.5% V, 4.6% W, and the rest is Fe. The average hardness at room temperature is 62HRC, and the high temperature hardness at 650℃ is 49HRC. After 30min of high temperature friction and wear at 650℃, the wear loss is 35.8mg.

[0053] Embodiment 4:

[0054] The invention discloses an iron-based wear-resistant surfacing self-protected flux-cored welding wire, comprising a cold-rolled steel strip outer skin and a flux core powder wrapped therein, wherein the flux core is composed of the following raw materials in percentage by mass: 55% high-carbon ferrochromium, 3.9% graphite, 14.8% ferromolybdenum, 7.9% ferroniobium, 2.5% ferrovanadium, 4.2% ferrotungsten, 1.5% ferrosilicomanganese, 4.6% rutile, 1.6% sodium fluorosilicate, 0.9% potassium feldspar and 2.7% fluorite powder.

[0055] Among them, high carbon ferrochromium contains 9wt% C, 68wt% Cr, and the powder particle size is 80-240 mesh. Ferromolybdenum contains 68wt% Mo, and the powder particle size is 80-150 mesh. Ferroniobium contains 60wt% Nb, and the powder particle size is 60-150 mesh. Ferrovanadium contains 52wt% V, and the particle size is 60-120 mesh. Ferrotungsten contains 77wt% W, and the particle size is 120-200 mesh. Ferrosilicomanganese contains 72wt% Mn and 17wt% Si, and the powder particle size is 80-240 mesh. Graphite contains 98.5wt% C, and the powder particle size is 80-120 mesh. Rutile contains 95% TiO2, and the particle size is 60-240 mesh. Sodium fluorosilicate has a purity of 99.5% and a particle size of 80-325 mesh. Potassium feldspar contains 12% K2O, 19% Al2O3 and 68% SiO2, with a particle size of 60 to 200 mesh. Fluorite powder contains 98% CaF2, with a particle size of 80 to 325 mesh.

[0056] The cold-rolled steel strip is H08A, and the dimensions of the steel strip are: 15 mm in width and 0.4 mm in thickness.

[0057] The rutile and fluorite powders are baked at high temperature (600°C) to remove their crystal water; sodium fluorosilicate and potassium feldspar are dried at medium and low temperature (350°C) to remove their moisture; high carbon ferrochrome, graphite, ferromolybdenum, ferroniobium, ferrovanadium, ferrotungsten and ferrosilicon manganese are dried at low temperature (240°C) to remove their moisture; the raw materials after the above treatments are mechanically mixed according to mass percentage to obtain a core powder material.

[0058] On the flux-cored welding wire production line, H08A cold-rolled steel strip is wrapped with evenly mixed flux-cored powder, which is then drawn and reduced to produce flux-cored welding wire with a diameter of 2.8 mm and a filling rate of 49%.

[0059] After two layers of open arc surfacing, the main chemical composition of the outer surface of the surfacing layer is 4.5wt% C, 0.5wt% Si, 0.8wt% Mn, 22wt% Cr, 4.1wt% Mo, 3.7wt% Nb, 1.2% V, 4.1% W, and the rest is Fe. The average hardness at room temperature is 64HRC, and the high temperature hardness at 650℃ is 52HRC. After 30min of high temperature friction and wear at 650℃, the wear loss is 24.8mg.

[0060] Embodiment 5:

[0061] The invention discloses an iron-based wear-resistant surfacing self-protected flux-cored welding wire, comprising a cold-rolled steel strip outer skin and a flux core powder wrapped therein, wherein the flux core is composed of the following raw materials in percentage by mass: 58% high-carbon ferrochromium, 3.5% graphite, 17.3% ferromolybdenum, 5.5% ferroniobium, 1.5% ferrovanadium, 3.5% ferrotungsten, 0.7% ferrosiliconmanganese, 3.7% rutile, 2.5% sodium fluorosilicate, 0.2% potassium feldspar and 1.9% fluorite powder.

[0062] Among them, high carbon ferrochromium contains 9.2wt% C, 69wt% Cr, and the powder particle size is 80-325 mesh. Ferromolybdenum contains 70wt% Mo, and the powder particle size is 80-150 mesh. Ferroniobium contains 65wt% Nb, and the powder particle size is 80-200 mesh. Ferrovanadium contains 55wt% V, and the particle size is 80-200 mesh. Ferrotungsten contains 79wt% W, and the particle size is 80-150 mesh. Ferrosilicomanganese contains 72wt% Mn and 19wt% Si, and the powder particle size is 60-240 mesh. Graphite contains 98.5wt% C, and the powder particle size is 60-120 mesh. Rutile contains 97% TiO2, and the particle size is 60-200 mesh. Sodium fluorosilicate has a purity of 99.5% and a particle size of 60-240 mesh. Potassium feldspar contains 14% K2O, 16% Al2O3 and 69% SiO2, with a particle size of 80 to 200 mesh. Fluorite powder contains 97.5% CaF2, with a particle size of 80 to 240 mesh.

[0063] The cold-rolled steel strip is H08A, and the dimensions of the steel strip are: 15 mm in width and 0.35 mm in thickness.

[0064] The rutile and fluorite powders are baked at high temperature (580°C) to remove their crystal water; sodium fluorosilicate and potassium feldspar are dried at medium and low temperature (320°C) to remove their moisture; high carbon ferrochrome, graphite, ferromolybdenum, ferroniobium, ferrovanadium, ferrotungsten and ferrosilicon manganese are dried at low temperature (200°C) to remove their moisture; the raw materials after the above treatments are mechanically mixed according to mass percentage to obtain a core powder material.

[0065] On the flux-cored welding wire production line, H08A thin steel strip is wrapped with evenly mixed flux-cored powder, which is then drawn and reduced to produce flux-cored welding wire with a diameter of 2.4 mm and a filling rate of 38%.

[0066] After two layers of open arc surfacing, the main chemical composition of the outer surface of the surfacing layer is 3.8wt% C, 0.35wt% Si, 0.5wt% Mn, 23wt% Cr, 6.2wt% Mo, 3.1wt% Nb, 0.9% V, 3.4% W, and the rest is Fe. The average hardness at room temperature is 60HRC, and the high temperature hardness at 650℃ is 47HRC. After 30min of high temperature friction and wear at 650℃, the wear loss is 41.3mg.

[0067] The above is only a preferred embodiment of the present invention. It should be pointed out that the present invention is not limited to the above embodiments. Without departing from the technical principles of the present invention, various changes can be made according to the invention purpose of the present invention. Any changes, modifications, substitutions, combinations, and simplifications made according to the spirit and principles of the technical solution of the present invention should be regarded as equivalent replacement methods, and these changes also belong to the protection scope of the present invention.

Claims

1. A self-protected flux-cored welding wire with a wide temperature range of 650°C or below, characterized in that: The invention comprises a cold-rolled steel strip outer skin and a flux core powder wrapped therein, wherein the flux core powder comprises the following components by mass percentage: 40% to 60% high-carbon ferrochromium, 1% to 6% graphite, 10% to 21% ferromolybdenum, 5% to 13% ferroniobium, 1% to 6% ferrovanadium, 3% to 8% ferrotungsten, 0% to 3% ferrosilicomanganese, 3% to 8% rutile, 1% to 4% sodium fluorosilicate, 0% to 3% potassium feldspar and 1% to 3% fluorite powder.

2. The self-shielded flux-cored welding wire with a wide temperature range of 650°C or below according to claim 1, characterized in that: The high carbon ferrochrome contains 7% to 9% C and ≥60% Cr; and the particle size is 60 to 325 meshes.

3. The self-shielded flux-cored welding wire with a wide temperature range of 650°C or below according to claim 1, characterized in that: The ferromolybdenum contains ≥60% Mo and has a particle size of 80-200 meshes; the ferroniobium contains ≥50% Nb and has a particle size of 60-200 meshes.

4. The self-shielded flux-cored welding wire with a wide temperature range of 650°C or below according to claim 1, characterized in that: The ferrovanadium contains 40% to 55% of V and has a particle size of 60 to 200 meshes; the ferrotungsten contains 75% to 80% of W and has a particle size of 80 to 200 meshes.

5. The self-shielded flux-cored welding wire for wear-resistant cladding in a wide temperature range of 650°C or below according to claim 1, characterized in that: The ferrosilicomanganese contains 65% to 72% of Mn and 17% to 20% of Si, and has a particle size of 60 to 325 meshes; the graphite contains ≥98% of C, and has a particle size of 60 to 120 meshes; the rutile contains ≥92% of TiO2, and has a particle size of 60 to 325 meshes.

6. The self-shielded flux-cored welding wire with a wide temperature range of 650°C or below according to claim 1, characterized in that: The purity of the sodium fluorosilicate is ≥99% and the particle size is 60-325 meshes.

7. The self-shielded flux-cored welding wire for wear-resistant cladding with a wide temperature range of 650°C or below according to claim 1, characterized in that: The potassium feldspar contains 9% to 16% of K2O, 65% to 70% of SiO2 and ≥16% of Al2O3; and the particle size is 60 to 325 meshes.

8. The self-shielded flux-cored welding wire for wear-resistant cladding in a wide temperature range of 650°C or below according to claim 1, characterized in that: The fluorite contains ≥96% of CaF2 and has a particle size of 60 to 325 meshes.

9. The self-shielded flux-cored welding wire for wear-resistant cladding in a wide temperature range of 650°C or below according to claim 1, characterized in that: The cold-rolled steel strip is H08A, and the dimensions of the steel strip are: 15-20 mm in width, and 0.35-0.6 mm in thickness.

10. A method for manufacturing a self-shielded flux-cored wire for wear-resistant cladding in a wide temperature range of 650°C or below as claimed in claim 1, characterized in that: The specific steps include: 1) The rutile and fluorite powders are subjected to a high temperature baking treatment at 550-800°C to remove the crystal water substances; 2) drying the sodium fluorosilicate and potassium feldspar at a medium to low temperature of 300 to 500° C. to remove moisture; 3) subjecting high carbon ferrochrome, graphite, ferromolybdenum, ferroniobium, ferrovanadium, ferrotungsten and ferrosilicon manganese to low temperature drying at 200-300°C to remove moisture; 4) Mechanically mixing the raw materials after the above treatment according to mass percentage to obtain a core powder material; 5) On a flux-cored welding wire production line, the flux-cored powder material of step 4) is uniformly wrapped with a cold-rolled steel strip, and is rolled and drawn into a flux-cored welding wire with a diameter of 2.4 to 3.2 mm, and the filling rate is controlled at 35% to 50%.

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