Modulated alloy core wire for wear-resistant steel and preparation method of modulated alloy core wire

Abstract

The invention is applicable to the technical field of alloying process and material processing, and provides a modulated alloy core wire for wear-resistant steel and a preparation method thereof, the alloy core wire comprises a core material and an outer-layer steel belt; the core material comprises the following chemical components in percentage by mass: 10-50% of Fe; b: 1%-5%; 5%-15% of V; 3%-8% of Nb; 1%-5% of Ti; 1%-5% of Ca; 1%-3% of Ba; 2%-10% of Al; 5%-20% of Si; and 2%-5% of rare earth elements, namely Ce and La. The method comprises the following steps: performing stirring and ball-milling mixing on powder under vacuum; filling a mold with the mixed powder in vacuum, carrying out compression molding, and then carrying out sectional sintering in vacuum; and finally, coating the sintered core material with a steel strip, and welding and sealing under vacuum. According to the prepared alloy core wire, the yield of easy-to-oxidize elements is remarkably increased, and the hardness, wear resistance and impact resistance of steel are enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of alloying technology and material processing, and in particular relates to a modulated alloy core wire for wear-resistant steel and a preparation method thereof. Background Art

[0002] With the development of modern industry, the demand for high-strength, wear-resistant and long-life steel is increasing. Wear-resistant high-strength steel is widely used in high-stress environments such as mining machinery, engineering machinery, and construction equipment, which require excellent strength, hardness and wear resistance. The traditional steelmaking alloying process improves the performance of steel by directly adding block or strip alloy elements, but this method has limitations in composition control, element absorption rate and uniformity, and it is difficult to meet the refined needs of high-performance steel.

[0003] Wire feeding technology is an effective method for adding alloy elements. By continuously feeding a core wire containing specific alloy elements into the molten steel, the alloy components can be released more evenly and accurately, thereby achieving precise composition control and improving the absorption efficiency of the alloy elements.

[0004] At present, traditional core wires mainly adopt a thin shell design that wraps the filling alloy powder. However, due to the complexity of powder filling and process limitations, this method is usually difficult to achieve the composite addition of multiple trace elements, and may cause problems such as uneven composition and unstable release. Powder metallurgy technology provides a more efficient option for the preparation of composite multi-alloy core wires. By uniformly mixing and sintering to form a dense material, the uniformity and absorption rate of the alloy composition can be improved. However, in practical applications, some alloy elements in the powder metallurgy process (especially active metals such as calcium and aluminum) are easily oxidized during high-temperature sintering, resulting in a decrease in component purity and a large loss during the steelmaking process, which reduces the recovery rate of these alloy elements. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a modulated alloy core wire for wear-resistant steel and a preparation method thereof, aiming to solve the problems raised in the above-mentioned background technology.

[0006] The embodiment of the present invention is implemented as follows: a modulated alloy core wire for wear-resistant steel includes a core material and an outer steel strip;

[0007] The chemical composition of the core material includes, by mass fraction, Fe: 10% to 50%; B: 1% to 5%; V: 5% to 15%; Nb: 3% to 8%; Ti: 1% to 5%; Ca: 1% to 5%; Ba: 1% to 3%; Al: 2% to 10%; Si: 5% to 20%; rare earth elements (Ce, La) 2% to 5%; wherein Ca, Ba and rare earth elements exist in the form of oxides and metals.

[0008] In a further technical solution, the B and Ti in the core material exist in the form of FeB and TiAlB respectively, and the components of the core material are configured in the following mass fraction ranges: iron powder: 30% to 50%; titanium dioxide: 2% to 20%; alumina: 5% to 18%; borax: 5% to 30%;

[0009] After the proportioning is completed, the mixture is calcined at 1650-1750°C for 2-4 hours, and then the product is crushed into particles with an average particle size of 100-450 μm.

[0010] In a further technical solution, the ratio of the mixed components should satisfy the following relationship:

[0011]

[0012] Where k is the revision coefficient, and its value range is: k∈[1.1,1.5], where: m Fe is the mass fraction of iron powder; is the mass fraction of titanium dioxide; is the mass fraction of aluminum oxide; m B is the mass fraction of boron; m O is the mass fraction of oxygen; m C is the mass fraction of carbon.

[0013] In a further technical solution, the hard phase forming elements include B, V, Ti and Nb, the purifying elements include Ca and Ba, and the mass ratio of the hard phase forming elements to the purifying elements should be proportioned according to the following formula:

[0014] (B+V+Ti+Nb) / (Ca+Ba)=0.6~6.

[0015] In a further technical solution, the ratio between the rare earth element and the purification element should be proportioned according to the following formula:

[0016] (Ca+Ba) / (Ce+La)=0.3~3.5.

[0017] According to a further technical solution, the ratio of Ca and Ba in the oxide and metal states needs to be controlled at 30-80%; the ratio of rare earth elements in the oxide state should be 35-80%; the total mass fraction of B, V, Nb and Ti is controlled at 15-25%; the total content of Ca, Ba, Al and rare earth elements is controlled at 8-35%.

[0018] According to a further technical solution, the particle size of the core material should be less than 2.5 mm, and its components include at least one of Fe, B, V, Nb, Ti, Al and Si and at least one of Ca and Ba; the particle size of the oxide powder should be less than 0.81 μm to 1.2 μm, and its components include at least one of CaO and BaO.

[0019] Another object of an embodiment of the present invention is to provide a method for preparing a modulated alloy core wire for wear-resistant steel, based on the above-mentioned modulated alloy core wire for wear-resistant steel, comprising the following steps:

[0020] Step 1: Powder preparation;

[0021] The alloy powders of Fe, B, V, Nb, Ti, Ca, Ba, Al, Si and rare earth elements are mixed in the required proportions; the powders with the good proportions are stirred, and after the stirring is completed, the powders are placed in a ball mill for ball milling;

[0022] The stirring and ball milling working environment are both vacuum conditions, and the vacuum degree is controlled at 10 -3 Torr~10 -5 Torr, ambient temperature is 18-26°C, and ambient humidity is controlled at 8%-10%;

[0023] Step 2: extrusion molding;

[0024] First, the prepared alloy powder was placed in a vacuum environment at a depth of 2.5 cm 3 / s~10.5cm 3 / s volume flow rate is filled into a predetermined cylindrical mold, a hole is opened at the other end of the mold, and a heating device is installed at the opening; during the filling process, the opening end is blocked to prevent powder leakage, and vibration is applied to the mold to avoid the generation of gaps; before formal pressing, the powder in the mold is lightly pre-pressed to increase the filling density of the powder; during formal pressing, the blocking device and the heating device at the opening are opened, and when the heating device reaches a preset temperature, the powder in the mold is started to be extruded and cut according to a preset length;

[0025] Step 3: Coating the steel strip;

[0026] After extrusion molding, when the core wire is cooled, the steel belt is used to wrap and seal the core wire to coat the obtained core material; after filling the core material, the two ends of the steel belt tube are welded and sealed, and the welding method is laser welding; the working environment of the coated steel belt is vacuum conditions, and the vacuum degree is controlled at 10 -3 Torr~10 -5 Torr.

[0027] A further technical solution is that in step 2, the compression ratio r of the extrusion molding ranges from 0.72 to 50.5, according to the following formula:

[0028]

[0029] v out = k·T

[0030]

[0031] Among them, v in is the inlet flow rate, cm 3 / s;v out is the outlet flow rate, cm 3 / s; A in is the inlet cross-sectional area, cm 3 ; A out is the outlet cross-sectional area, cm 3 ;D in is the inlet diameter, cm; D out is the outlet diameter, cm; T is the ambient temperature, ℃; k is a constant, ranging from 0.02 to 0.1.

[0032] The embodiments of the present invention provide a modulated alloy core wire for wear-resistant steel and a preparation method thereof, and the beneficial effects thereof are as follows:

[0033] (1) Through the vacuum powder metallurgy process, the core material is sintered in a vacuum or inert gas environment, which effectively avoids the oxidation loss of easily oxidized elements such as calcium, barium, and aluminum, and significantly improves the recovery rate of alloy elements.

[0034] (2) Compared with the traditional process, this method can retain more active elements during the extrusion molding process, improve the utilization efficiency of alloy components, and reduce production costs.

[0035] (3) The prepared core wire contains elements such as boron, vanadium, titanium, and niobium, which form hard phases or microalloying in steel, which can effectively improve the wear resistance and strength of steel. Compared with traditional core wire materials, the multi-alloy core wire prepared by this method can more evenly distribute the wear-resistant elements in the steel, enhance the service life and load-bearing capacity of the steel, and is particularly suitable for applications with high strength and wear resistance requirements.

[0036] (4) The combined effect of the vacuum sintering environment and rare earth elements makes the internal structure of the steel more uniform and the grains finer. Compared with traditional processes, it effectively reduces the problems of inclusions and stress concentration, and improves the toughness and impact resistance of the material.

[0037] (5) The multi-alloy core wire prepared by this method utilizes the synergistic effect of calcium, barium and rare earth elements to optimize the inclusion morphology in the steel, making the inclusions present a more uniform and fine distribution. This improved inclusion morphology can reduce stress concentration points, thereby improving the ductility and impact resistance of the steel, making it more suitable for engineering applications requiring high toughness.

[0038] (6) This method uses a multi-alloy powder formula, which can flexibly adjust the content of different elements according to specific needs, and can accurately control the core wire composition during the production process. Compared with the traditional alloying process, this method can achieve a combination of multiple alloy elements, making the performance of the core wire more adjustable and suitable for the production of steel for various special purposes.

[0039] (7) The use of laser welding technology in a vacuum environment can ensure that the welding parts are free of oxidation and pores, and the weld quality is higher. The combination of steel strip wrapping and vacuum laser welding greatly improves the sealing and overall strength of the core wire. Compared with traditional processes, the risk of core wire breakage and leakage during transportation and use is significantly reduced. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0042] An embodiment of the present invention provides a modulated alloy core wire for wear-resistant steel, comprising a core material and an outer steel strip;

[0043] The chemical composition of the core material includes, by mass fraction, 10% to 50% iron (Fe), 1% to 5% boron (B), 5% to 15% vanadium (V), 3% to 8% niobium (Nb), 1% to 5% titanium (Ti), 1% to 5% calcium (Ca), 1% to 3% barium (Ba), 2% to 10% aluminum (Al), 5% to 20% silicon (Si), and 2% to 5% rare earth elements (Ce, La); wherein calcium, barium and rare earth elements (Ce, La) exist in the form of oxides and metals.

[0044] As a preferred embodiment of the present invention, the boron element and titanium element in the core material exist in the form of FeB and TiAlB respectively, and the components of the core material are configured in the following mass fraction range: iron powder: 30% to 50%; titanium dioxide: 2% to 20%; aluminum oxide: 5% to 18%; borax: 5% to 30%. After the proportions are completed, calcination is carried out at 1650-1750°C for 2 to 4 hours, and then the product is crushed into particles with an average particle size of 100-450μm.

[0045] As a preferred embodiment of the present invention, in order to ensure that the composition ratio of FeB and TiAlB is appropriate and satisfy the mass balance of the reactants, the ratio of the mixed components should satisfy the following relationship:

[0046]

[0047] Where k is the revision coefficient, and its value range is: k∈[1.1,1.5], where: m Fe is the mass fraction of iron powder; is the mass fraction of titanium dioxide; is the mass fraction of aluminum oxide; m B is the mass fraction of boron; m O is the mass fraction of oxygen; m C is the mass fraction of carbon.

[0048] As a preferred embodiment of the present invention, the mass ratio of the hard phase forming elements (B, V, Ti and Nb) to the purifying elements (Ca and Ba) should be proportioned according to the following formula:

[0049] (B+V+Ti+Nb) / (Ca+Ba)=0.6~6.

[0050] As a preferred embodiment of the present invention, the ratio between the rare earth element and the purification element should be formulated according to the following formula:

[0051] (Ca+Ba) / (Ce+La)=0.3~3.5.

[0052] As a preferred embodiment of the present invention, the ratio of Ca and Ba in the oxide and metal states needs to be controlled at 30% to 80%; the ratio of rare earth elements (Ce, La) in the oxide state should be 35% to 80%; the total mass fraction of boron (B), vanadium (V), niobium (Nb), and titanium (Ti) is controlled at 15% to 25%; the total content of calcium (Ca), barium (Ba), aluminum (Al) and rare earth elements (Ce, La) is controlled at 8% to 35%.

[0053] As a preferred embodiment of the present invention, the particle size of the core material should be less than 2.5 mm, and its components include at least one of Fe, B, V, Nb, Ti, Al and Si and at least one of Ca and Ba; the particle size of the oxide powder should be less than 0.81 μm to 1.2 μm, and its components include at least one of CaO and BaO.

[0054] Another embodiment of the present invention provides a method for preparing a modulated alloy core wire for wear-resistant steel, based on the above-mentioned modulated alloy core wire for wear-resistant steel, comprising the following steps:

[0055] Step 1: Powder preparation;

[0056] Mix the alloy powders of Fe, B, V, Nb, Ti, Ca, Ba, Al, Si and rare earth elements (Ce, La) in the required proportions. Stir the proportioned powders with a mechanical stirrer, wherein the stirrer speed is controlled at 50r / min to 200r / min, and the stirring time is 0.8h-3.5h. After stirring, put the powder into a ball mill for ball milling, the ball mill speed is controlled at 200r / min to 500r / min, the ball-to-material ratio is 4.5 to 10:1 (mass ratio of balls to powder), the ball milling time is 2h to 6h, and the ball milling medium is selected from stainless steel balls or tungsten carbide balls. In addition, the stirring and ball milling working environments are both vacuum conditions, and the vacuum degree is controlled at 10 -3 Torr~10 -5 Torr, the ambient temperature is 18-26℃, and the ambient humidity is controlled at 8%-10%.

[0057] Step 2: extrusion molding;

[0058] First, the prepared alloy powder was placed in a vacuum environment at a depth of 2.5 cm 3 / s~10.5cm 3 / s volume flow rate is filled into a predetermined cylindrical mold. The mold size is 100mm~275mm in outer diameter, 4mm~10mm in wall thickness, 0.3m~3m in length, and the mold material is hot working die steel. A hole is opened at the other end of the mold with a hole diameter of 20mm~65mm, and a heating device is installed at the opening. The heating temperature is 700℃~1100℃. During the filling process, the opening end is blocked to prevent powder leakage, and the mold is vibrated to avoid the generation of gaps. The vibration frequency is 40Hz~110Hz. Before formal pressing, the powder in the mold is lightly pre-pressed to increase the filling density of the powder. The pre-pressing pressure is 4Mpa~15Mpa, the pressing speed is 1mm / s~16mm / s, and the holding time is set to 10s~110s. During the formal pressing, the blocking device and the heating device at the opening are opened. When the heating device reaches the preset temperature, the powder in the mold is extruded and formed. The pressing speed is 3mm / s to 20mm / s, and the powder is cut according to the preset length.

[0059] Step 3: Coating the steel strip;

[0060] After extrusion molding, when the core wire cools down, a steel strip with a thickness of 0.2mm to 1.6mm and a width of 0.2m to 1m is used to wrap and seal the core wire. The winding speed is 10 to 40r / min to coat the obtained core material. The size of the steel strip tube is processed according to the size of the powder metallurgy core material. The steel strip material is low carbon steel (Q195, Q235), 304 stainless steel or low alloy steel. After filling the core material, the two ends of the steel strip tube are welded and sealed. Laser welding is used for welding. In addition, the working environment of the coated steel strip is vacuum conditions, and the vacuum degree is controlled at 10 -3 Torr~10 -5 Torr, the ambient temperature is 18 ~ 33 ℃, the ambient humidity is controlled at 8% ~ 10%, and it is equipped with a water cooling system to prevent high heat from being generated during welding.

[0061] As a preferred embodiment of the present invention, in step 2, the compression ratio r of the extrusion molding ranges from 0.72 to 50.5, according to the following formula:

[0062]

[0063]

[0064] V out = k·T

[0065]

[0066] Among them, v in is the inlet flow rate, cm 3 / s;v out is the outlet flow rate, cm 3 / s; A in is the inlet cross-sectional area, cm 3 ; A out is the outlet cross-sectional area, cm 3 ;D in is the inlet diameter, cm; D out is the outlet diameter, cm; T is the ambient temperature, ℃; k is a constant, ranging from 0.02 to 0.1.

[0067] Two specific embodiments are provided below to describe the specific implementation of this method in detail.

[0068] Embodiment 1:

[0069] A modulated alloy core wire for wear-resistant steel is composed of a core material and an outer steel strip; wherein the chemical composition of the core material includes, by mass fraction: Fe: (depending on the reaction of FeB and TiAlB), B: (added in the form of FeB), V: 9.06%, Nb: 5.41%, Ti: (added in the form of TiAlB), Ca: 3.09%, Ba: 1%, Al: (the total value of alumina and aluminum powder required for the reaction of FeB and TiAlB), Si: 16.33%, and rare earth elements (Ce, La): 4.93%.

[0070] Boron and titanium are added in the form of FeB and TiAlB, using iron powder, titanium dioxide, alumina, borax and graphite, with the following mass fractions: iron powder: 47.36%; titanium dioxide: 3.66% (of which the mass fraction of titanium is 2.19%); alumina: 14.01% (of which the mass fraction of aluminum is 7.41%); borax: 27.06% (of which the mass fraction of boron is 3.22%). In order to ensure that the composition ratio of FeB and TiAlB is appropriate and to satisfy the mass balance of the reactants, the proportion of the mixed components meets m O =52.09%, m C =76.40% (K is 1) After mixing the components, they were calcined at 1670°C for 2.5 hours to form FeB and TiAlB, and then the product was crushed into particles with an average particle size of 230 μm.

[0071] The chemical components are calculated according to the mass fraction and related formulas, among which: the ratio of hard phase forming elements to purification elements is 1.21, and the ratio of rare earth to purification elements is 1.2. The ratio of Ca and Ba in oxide and metal state is 49.09%. The ratio of rare earth elements (Ce, La) in oxide state is 50.43%. The total mass fraction of boron (B), vanadium (V), niobium (Nb), and titanium (Ti) is 19.88%. The total content of calcium (Ca), barium (Ba), aluminum (Al) and rare earth elements (Ce, La) is 16.43%.

[0072] The specific preparation method of the alloy core wire is as follows:

[0073] Step 1: Powder preparation;

[0074] The proportioned powder is first stirred by a mechanical stirrer, wherein the stirrer speed is controlled at 50r / min and the stirring time is 0.9h. After the stirring is completed, the powder is placed in a ball mill for ball milling, the ball mill speed is controlled at 240r / min, the ball-to-material ratio is 5:1 (ball-to-powder mass ratio), the ball milling time is 2.5h, and the ball milling medium is selected from stainless steel balls. In addition, the stirring and ball milling working environments are both vacuum conditions, the vacuum degree is controlled at 10-3Torr, the ambient temperature is 20°C, and the ambient humidity is controlled at 9%.

[0075] Step 2: extrusion molding;

[0076] First, the prepared alloy powder was placed in a vacuum environment at a depth of 2.5 cm 3 / s volume flow rate is filled into a predetermined cylindrical mold. The mold size is 150mm in outer diameter, 5mm in wall thickness, 1.5m in length, and the mold material is hot working die steel. A hole is opened at the other end of the mold with a hole diameter of 16mm, and a heating device is installed at the opening. The heating temperature is 900℃. During the filling process, the opening end is blocked to prevent powder leakage, and the mold is vibrated to avoid the generation of voids. The vibration frequency is 50Hz. Before the formal pressing, the powder in the mold is lightly pre-pressed to increase the filling density of the powder. The pre-pressing pressure is 6Mpa, the pressing speed is 3mm / s, and the holding time is set to 30s. During the formal pressing, the blocking device and the heating device at the opening are opened. When the heating device reaches the preset temperature, the powder in the mold is extruded and formed. The compression ratio is about 19.65 (k is 0.07), the pressing speed is 10mm / s, and it is cut according to the preset length.

[0077] The extrusion molding environment is a vacuum condition, the vacuum degree is controlled at 10-3 Torr, the ambient temperature is 50°C, and the ambient humidity is controlled at 8%.

[0078] Step 3: Coating the steel strip;

[0079] After extrusion molding, when the core wire is cooled, a steel strip with a thickness of 0.3mm and a width of 0.5m is used to wrap and seal the core wire. The winding speed is 12r / min to coat the obtained core material. Among them, the size of the steel strip tube is processed according to the size of the powder metallurgy core material. The steel strip material is Q235 low-carbon steel. After filling the core material, the two ends of the steel strip tube are welded and sealed. The welding method is laser welding. In addition, the working environment of the coated steel strip is vacuum conditions, the vacuum degree is controlled at 10-3Torr, the ambient temperature is 23℃, and the ambient humidity is controlled at 8%.

[0080] The alloy core wire prepared in this embodiment and the core wire prepared by the existing powder coating method with the same core material composition as that in this embodiment were fed into the crystallizer at the same wire feeding position and wire feeding speed using a wire feeder, and finally an alloy steel sample was obtained. At one-half of the thickness direction of the cross-section of the alloy steel sample, samples were taken to measure the yield of easily oxidizable elements such as calcium, barium, and aluminum, as well as the hardness, wear resistance, and impact toughness of the steel part. The measurement results are shown in Table 1.

[0081] Table 1: Performance test results in Example 1

[0082]

[0083] Embodiment 2:

[0084] A modulated alloy core wire for wear-resistant steel consists of a core material and an outer steel strip; wherein the chemical composition of the core material includes, by mass fraction: Fe: (depending on the reaction of FeB and TiAlB), B: (added in the form of FeB), V: 8.50%, Nb: 3.89%, Ti: (added in the form of TiAlB), Ca: 3.14%, Ba: 1.21%, Al: (the total value of alumina and aluminum powder required for the reaction of FeB and TiAlB), Si: 18.98%, and rare earth elements (Ce, La): 4.26%.

[0085] The boron and titanium elements are added in the form of FeB and TiAlB, using iron powder, titanium dioxide, aluminum oxide, borax and graphite, with the following mass fractions: iron powder: 45.94%; titanium dioxide: 5.93% (of which the mass fraction of titanium is 3.55%); aluminum oxide: 15.73% (of which the mass fraction of aluminum is 8.32%); borax: 19.73% (of which the mass fraction of boron is 2.23%). In order to ensure that the proportion of FeB and TiAlB is appropriate and to satisfy the mass balance of the reactants, the proportion of the mixed components meets m O =74.66%, m C =109.42% (K is 1.1) After the components are mixed, they are calcined at 1700°C for 3.5 hours to form FeB and TiAlB, and then the product is crushed into particles with an average particle size of 150 μm.

[0086] The chemical composition is calculated by mass fraction and related formulas, among which: the ratio of hard phase forming elements to purification elements is 1.07, and the ratio of rare earth to purification elements is 0.98. The ratio of Ca and Ba in oxide and metal state is 43.94%. The ratio of rare earth elements (Ce, La) in oxide state is 38.26%. The total mass fraction of boron (B), vanadium (V), niobium (Nb), and titanium (Ti) is 18.17%. The total content of calcium (Ca), barium (Ba), aluminum (Al) and rare earth elements (Ce, La) is 16.92%.

[0087] The method for preparing the alloy core wire comprises the following steps:

[0088] Step 1: Powder preparation;

[0089] The proportioned powder is first stirred by a mechanical stirrer, wherein the stirrer speed is controlled at 100r / min and the stirring time is 1.5h. After the stirring is completed, the powder is placed in a ball mill for ball milling, the ball mill speed is controlled at 310r / min, the ball-to-material ratio is 6:1 (ball-to-powder mass ratio), the ball milling time is 3.3h, and the ball milling medium is selected from stainless steel balls. In addition, the stirring and ball milling working environments are all vacuum conditions, the vacuum degree is controlled at 10-4Torr, the ambient temperature is 22°C, and the ambient humidity is controlled at 8%.

[0090] Step 2: extrusion molding;

[0091] First, the prepared alloy powder is loaded into a predetermined cylindrical mold at a volume flow rate of 3.5cm3 / s in a vacuum environment. The mold size is 200mm in outer diameter, 5mm in wall thickness, and 1.7m in length. The mold material is hot working die steel. A hole is opened at the other end of the mold with a hole diameter of 16mm, and a heating device is installed at the opening. The heating temperature is 1000℃. During the filling process, the opening end is blocked to prevent powder leakage, and the mold is vibrated to avoid the generation of voids. The vibration frequency is 60Hz. Before the formal pressing, the powder in the mold is lightly pre-pressed to increase the packing density of the powder. The pre-pressing pressure is 10Mpa, the pressing speed is 5mm / s, and the holding time is set to 50s. During the formal pressing, the blocking device and the heating device at the opening are opened. When the heating device reaches the preset temperature, the powder in the mold is extruded and formed. The compression ratio is about 11.67 (k is 0.07), the pressing speed is 15mm / s, and it is cut according to the preset length.

[0092] The extrusion molding environment is a vacuum condition, the vacuum degree is controlled at 10-3 Torr, the ambient temperature is 70°C, and the ambient humidity is controlled at 8%.

[0093] Step 3: Coating the steel strip;

[0094] After extrusion molding, when the core wire cools down, a steel strip with a thickness of 0.2mm and a width of 0.5m is used to wrap and seal the core wire. The winding speed is 15r / min to coat the obtained core material. Among them, the size of the steel strip tube is processed according to the size of the powder metallurgy core material. The steel strip material is low-alloy steel. After filling the core material, the two ends of the steel strip tube are welded and sealed. The welding method is laser welding. In addition, the working environment of the coated steel strip is vacuum conditions, the vacuum degree is controlled at 10-3Torr, the ambient temperature is 30℃, and the ambient humidity is controlled at 8%.

[0095] The alloy core wire prepared in this embodiment and the core wire prepared by the existing powder coating method with the same core material composition as that in this embodiment were fed into the crystallizer at the same wire feeding position and wire feeding speed using a wire feeder, and finally the alloy steel sample was obtained. At one-half of the thickness direction of the cross section of the alloy steel sample, samples were taken to measure the yield of easily oxidizable elements such as calcium, barium, and aluminum, as well as the hardness, wear resistance, and impact toughness of the steel part. The measurement results are shown in Table 2.

[0096] Table 2: Performance test results in Example 2

[0097]

[0098] It can be seen from Examples 1 and 2 that the alloy core wire prepared by the present method has obvious improvements in various performance parameters.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A modulated alloy core wire for wear-resistant steel, characterized in that: Including core material and outer steel belt; The chemical composition of the core material includes, by mass fraction, Fe: 10% to 50%; B: 1% to 5%; V: 5% to 15%; Nb: 3% to 8%; Ti: 1% to 5%; Ca: 1% to 5%; Ba: 1% to 3%; Al: 2% to 10%; Si: 5% to 20%; rare earth elements, namely Ce and La: 2% to 5%; wherein Ca, Ba and rare earth elements exist in the form of oxides and metals.

2. The wear-resistant steel modulated alloy core wire according to claim 1, characterized in that: The B and Ti in the core material exist in the form of FeB and TiAlB respectively, and the components of the core material are configured in the following mass fraction ranges: iron powder: 30% to 50%; titanium dioxide: 2% to 20%; aluminum oxide: 5% to 18%; borax: 5% to 30%; After the proportioning is completed, the mixture is calcined at 1650-1750°C for 2-4 hours, and then the product is crushed into particles with an average particle size of 100-450 μm.

3. The wear-resistant steel modulated alloy core wire according to claim 2, characterized in that: The proportions of the mixed ingredients should satisfy the following relationship: Among them, k is the revision coefficient, the value range is: k∈[1.1,1.5], among which: m Fe is the mass fraction of iron powder; is the mass fraction of titanium dioxide; is the mass fraction of aluminum oxide; m B is the mass fraction of boron; m O is the mass fraction of oxygen; m C is the mass fraction of carbon.

4. The wear-resistant steel modulated alloy core wire according to claim 2, characterized in that: The hard phase forming elements include B, V, Ti and Nb, and the purifying elements include Ca and Ba. The mass ratio of the hard phase forming elements to the purifying elements is formulated according to the following formula: (B+V+Ti+Nb) / (Ca+Ba)=0.6~6.

5. The wear-resistant steel modulated alloy core wire according to claim 2, characterized in that: The ratio between rare earth elements and purification elements should be matched according to the following formula: (Ca+Ba) / (Ce+La)=0.3~3.

5.

6. The modulated alloy core wire for wear-resistant steel according to claim 2, characterized in that: The ratio of Ca and Ba in the oxide and metal states needs to be controlled at 30-80%; the ratio of rare earth elements in the oxide state should be 35%-80%; the total mass fraction of B, V, Nb and Ti is controlled at 15%-25%; the total content of Ca, Ba, Al and rare earth elements is controlled at 8%-35%.

7. A method for preparing a modulated alloy core wire for wear-resistant steel, based on the modulated alloy core wire for wear-resistant steel according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Powder preparation; The alloy powders of Fe, B, V, Nb, Ti, Ca, Ba, Al, Si and rare earth elements are mixed in the required proportions; the powders with the good proportions are stirred, and after the stirring is completed, the powders are placed in a ball mill for ball milling; The stirring and ball milling working environment are both vacuum conditions, and the vacuum degree is controlled at 10 -3 Torr~10 -5 Torr, ambient temperature is 18-26°C, and ambient humidity is controlled at 8%-10%; Step 2: extrusion molding; First, the prepared alloy powder was placed in a vacuum environment at a depth of 2.5 cm 3 / s~10.5cm 3 / s volume flow rate is filled into a predetermined cylindrical mold, a hole is opened at the other end of the mold, and a heating device is installed at the opening; during the filling process, the opening end is blocked to prevent powder leakage, and vibration is applied to the mold to avoid the generation of gaps; before formal pressing, the powder in the mold is lightly pre-pressed to increase the filling density of the powder; during formal pressing, the blocking device and the heating device at the opening are opened, and when the heating device reaches a preset temperature, the powder in the mold is started to be extruded and cut according to a preset length; Step 3: Coating the steel strip; After extrusion molding, when the core wire is cooled, the steel belt is used to wrap and seal the core wire to coat the obtained core material; after filling the core material, the two ends of the steel belt tube are welded and sealed, and the welding method is laser welding; the working environment of the coated steel belt is vacuum conditions, and the vacuum degree is controlled at 10 -3 Torr~10 -5 Torr.

8. The method for preparing a modulated alloy core wire for wear-resistant steel according to claim 7, characterized in that: In step 1, the stirring process is carried out by a mechanical stirrer, wherein the stirrer speed is controlled at 50 r / min to 200 r / min, and the stirring time is 0.8 h to 3.5 h; The ball mill speed is controlled at 200 r / min to 500 r / min, the ball to powder mass ratio is 4.5 to 10:1, the ball milling time is 2 h to 6 h, and the ball milling medium is selected from stainless steel balls or tungsten carbide balls.

9. The method for preparing a modulated alloy core wire for wear-resistant steel according to claim 7, characterized in that: In step 2, the mold size is 100 mm to 275 mm in outer diameter, 4 mm to 10 mm in wall thickness, 0.3 m to 3 m in length, the mold material is hot working die steel, and the diameter of the mold opening is 20 mm to 65 mm; The heating temperature of the heating device is 700°C to 1100°C; The vibration frequency of the mold is 40Hz~110Hz; The pre-pressing pressure of light pre-pressing is 4Mpa~15Mpa, the pressing speed is 1mm / s~16mm / s, and the holding time is set to 10s~110s; The pressing speed during the formal pressing is 3 mm / s to 20 mm / s.

10. The method for preparing a modulated alloy core wire for wear-resistant steel according to claim 9, characterized in that: In step 2, the compression ratio r of the extrusion molding ranges from 0.72 to 50.5, according to the following formula: v out =k·T Among them, v in is the inlet flow rate, cm 3 / s;v out is the outlet flow rate, cm 3 / s; A in is the inlet cross-sectional area, cm 3 ; A out is the outlet cross-sectional area, cm 3 ;D in is the inlet diameter, cm; D out is the outlet diameter, cm; T is the ambient temperature, ℃; k is a constant, ranging from 0.02 to 0.

1.

11. The method for preparing a modulated alloy core wire for wear-resistant steel according to claim 7, characterized in that: In step 3, The thickness of the outer steel belt is 0.2mm~1.6mm, and the width is 0.2m~1m; The winding speed of the steel belt is 10~40r / min; The steel strip is made of low carbon steel, 304 stainless steel or low alloy steel.

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