A high hardness crack-free flux cored wire and a method of making the same

Abstract

This invention provides a high-hardness, crack-free flux-cored welding wire and its preparation method. The flux-cored welding wire includes an outer sheath and a flux core. By weight, the flux core comprises the following components: boron carbide 5.6-8.6 parts; 75% ferrosilicon 3.1-4.6 parts; electrolytic manganese 0.6-1.6 parts; 80% ferrovanadium 0.3-1.2 parts; nickel powder 0.3-1.0 parts; 68% high-carbon ferrochrome 67.5-94.5 parts; and iron powder 6-6.5 parts. The preparation method of the flux-cored welding wire is as follows: [The following components are listed:] boron carbide, 75% ferrosilicon, electrolytic manganese, 80% ferrovanadium... Ferrovanadium, nickel powder, 68% high-carbon ferrochrome, and iron powder are added sequentially to a dryer and dried for 2-3 hours. The mixture is then thoroughly mixed using a three-dimensional motion mixer and placed in an insulated box for later use. The outer sheath is placed on a forming machine, which rolls the outer steel strip into a U-shaped groove. Flux-cored powder is added to the U-shaped groove, and the forming machine closes and pulls the groove to obtain the flux-cored welding wire. The flux-cored welding wire of this invention features high hardness, no cracks, high temperature resistance, and corrosion resistance. Furthermore, the low production cost of the flux-cored welding wire facilitates industrial production.

Description

Technical Field

[0001] This invention belongs to the field of materials processing and welding materials, and in particular relates to a high-hardness, crack-free flux-cored welding wire and its preparation method. Background Technology

[0002] Flux-cored welding wire, also known as powder-cored welding wire or tubular welding wire, is divided into two main categories: gas-shielded and non-gas-shielded. The surface of flux-cored welding wire is the same as that of solid welding wire, made of materials with good plasticity such as low-carbon steel or low-alloy steel.

[0003] Currently used flux-cored welding wires are prone to cracking and breakage during surfacing, affecting their performance in surfacing applications.

[0004] Therefore, there is a need to provide a flux-cored welding wire that is crack-free and has high hardness, as well as a method for its preparation. Summary of the Invention

[0005] One object of the present invention is to provide a high-hardness, crack-free flux-cored welding wire, and another object of the present invention is to provide a method for preparing the aforementioned high-hardness, crack-free flux-cored welding wire.

[0006] To achieve the first objective of this invention, the following technical solution is adopted:

[0007] A high-hardness, crack-free flux-cored welding wire, comprising an outer sheath and a flux core filled within the outer sheath, wherein the flux core comprises the following components by weight:

[0008] Boron carbide 5.6-8.6 parts; 75% ferrosilicon 3.1-4.6 parts; electrolytic manganese 0.6-1.6 parts; 80% ferrovanadium 0.3-1.2 parts; nickel powder 0.3-1.0 parts; 68% high-carbon ferrochrome 67.5-94.5 parts; iron powder 5.7-6.7 parts;

[0009] The powder filling rate within the core is 30-45%.

[0010] Preferably, the core comprises the following components by weight:

[0011] Boron carbide 7.1 parts; 75% ferrosilicon 3.7 parts; electrolytic manganese 1.0 part; 80% ferrovanadium 0.6 parts; nickel powder 0.5 parts; 68% high-carbon ferrochrome 81 parts; iron powder 6.2 parts.

[0012] Preferably, the powder filling rate within the core is 45%.

[0013] Preferably, the chemical composition of the fused metal of the core comprises, by weight percentage, the following components:

[0014] Boron: 1.8–2.8%; Carbon: 1.5–2.5%; Silicon: 1–1.5%; Manganese: 0.3–0.8%; Vanadium: 0.1–0.4%; Nickel: 0.1–0.4%; Chromium: 20–28%, with the balance being iron.

[0015] The present invention will be further described below:

[0016] In this invention, the flux-cored welding wire needs to be used for surfacing operations. Therefore, there are certain requirements for the physical and chemical properties of the flux-cored welding wire. For example, the flux-cored welding wire needs to have high hardness and no cracks. In addition, the flux-cored welding wire also needs to have high temperature resistance and corrosion resistance. Based on this, the flux-cored welding wire of this invention was developed.

[0017] In this invention, each component of the flux-cored wire has a corresponding function, as detailed below:

[0018] Boron carbide has high wear resistance, high hardness and good chemical stability. Boron carbide can improve the hardness and wear resistance of flux-cored welding wire.

[0019] 75% ferrosilicon refers to a ferrosilicon alloy with a silicon content of 75%. In this alloy, silicon atoms and iron atoms combine to form silicon-containing ferrite with strong covalent bonds. This not only promotes the formation of ferrite but also significantly strengthens it. The combination of the two improves the strength, plasticity, and toughness of the flux-cored wire.

[0020] Electrolytic manganese has high strength and hardness, as well as certain plasticity and toughness, which can improve the strength, hardness and toughness of flux-cored welding wire.

[0021] 80% ferrovanadium refers to a ferrovanadium alloy with a vanadium content of 80%. It has good corrosion resistance and can remain stable in harsh chemical environments, which can improve the corrosion resistance of flux-cored welding wire.

[0022] Nickel powder has good corrosion resistance, is not easily oxidized in air, and is resistant to strong alkalis. In addition, nickel powder also has good plasticity. Therefore, nickel powder can improve the corrosion resistance and plasticity of flux-cored welding wire.

[0023] 68% high-carbon ferrochrome refers to a ferrochrome alloy with a chromium content of 68%. It has good chemical stability, wear resistance and high hardness, and therefore can improve the wear resistance and hardness of flux-cored welding wire.

[0024] Iron powder can be added to the deposition rate of flux-cored welding wire, and combined with other metals to form a weld with certain strength and toughness.

[0025] In this invention, the flux filling rate of the core is 30-45%. Under normal circumstances, the filling rate needs to be kept appropriate; otherwise, it will affect the performance of the flux-cored wire and the stability of the welding process. If the filling rate is too low, the wire may not be fully filled, which may lead to powder leakage in subsequent processes. Furthermore, the wire may be easily flattened by the wire feeding wheel during welding, resulting in uneven wire feeding. At the same time, due to the relatively loose structure of the wire, the amount of gas introduced into the molten pool increases, which may cause porosity in the weld. Conversely, if the filling rate is too high, it will increase the difficulty of rolling and drawing. In more extreme cases, the outer sheath may not be able to cover the core powder, resulting in waste of core powder leakage and affecting the rolling process. Therefore, it is necessary to select an appropriate filling rate. In this invention, after multiple experiments and demonstrations, the preferred filling rate of the core is 45%, which can produce a better filling effect, and the flux-cored wire obtained by rolling and drawing has a good condition.

[0026] In this invention, the chemical composition of the metal plating in the core also plays a corresponding role, specifically:

[0027] The role of boron (B) is to strengthen the matrix and refine the grains, thereby improving the strength, hardness, plasticity and toughness of flux-cored welding wire;

[0028] The role of carbon (C) is to strengthen the matrix and generate a hard phase, thereby giving the flux-cored wire a high-hardness, high-melting-point phase;

[0029] The role of silicon (Si) is to strengthen the matrix and suture grain boundaries, making the grain boundaries between grains in the flux-cored wire more regular and compact, thereby improving the strength, plasticity and toughness of the flux-cored wire.

[0030] The role of manganese (Mn) is to strengthen and toughen the matrix, thereby improving the strength and toughness of the flux-cored wire, absorbing the energy generated during welding, and reducing the generation and propagation of cracks.

[0031] The role of vanadium (V) is to refine grains and generate a dispersed, high-hardness, non-sharp-angled reinforcing phase, thereby enhancing the strength and hardness of the flux-cored wire. Because it lacks sharp angles, the reinforcing phase can distribute stress more evenly, avoiding stress concentration and reducing localized damage and crack initiation. The reinforcing phase can also form a barrier within the material, hindering the propagation of existing cracks and thus improving the fracture toughness of the flux-cored wire. Furthermore, the reinforcing phase also possesses good thermal stability and wear resistance, giving the flux-cored wire high wear resistance and temperature resistance.

[0032] The role of nickel (Ni) is to strengthen and toughen the matrix and neutralize the properties of the hard phase, thereby improving the strength and toughness of the flux-cored wire. It can also inhibit crack propagation and help improve the overall stability and durability of the flux-cored wire.

[0033] Chromium (Cr) plays a role in neutralizing and optimizing the matrix, enhancing biocompatibility, and reducing crack tendency, thereby reducing the generation of cracks in flux-cored welding wire.

[0034] To achieve the second objective of this invention, the following technical solution is adopted:

[0035] A method for preparing a high-hardness, crack-free flux-cored welding wire as described above includes the following steps:

[0036] S1. Add boron carbide, 75% ferrosilicon, electrolytic manganese, 80% ferrovanadium, nickel powder, 68% high-carbon ferrochrome and iron powder to a dryer at 180-220℃ and dry for 2-3 hours. Then put the dryer into a three-dimensional motion mixer at 200℃ and mix thoroughly. Then put the mixture into a heat preservation box at 140-160℃ and keep it warm. Set aside the obtained core powder.

[0037] S2. Place the outer skin on the forming machine, and the forming machine rolls the outer skin steel strip into a U-shaped groove;

[0038] S3. Add the core powder to the U-shaped groove and control the powder filling rate in the core to be 30-45%. The forming machine rolls and closes the U-shaped groove after adding the core powder and pulls it to obtain the core welding wire.

[0039] Preferably, the temperature of the dryer is 200°C, and the temperature of the insulation box is 150°C.

[0040] Preferably, the outer sheath is a low-carbon steel strip. In this invention, high-quality low-carbon steel strip is selected as the outer sheath of the flux-cored welding wire.

[0041] More preferably, the low-carbon steel strip has a thickness of 0.4 mm and a width of 14 mm.

[0042] Preferably, in step S3, the welding wire is wiped with anhydrous ethanol before drawing.

[0043] Preferably, the diameter of the flux-cored wire obtained by drawing is 2.8 mm.

[0044] Preferably, the preparation method may further include the following steps:

[0045] S4. Wind the flux-cored welding wire layer into a disc to obtain a high wear-resistant flux-cored welding wire product for mold steel.

[0046] The beneficial effects of this invention are:

[0047] The flux-cored welding wire of the present invention has the following properties:

[0048] ① In this invention, the addition of boron carbide and 68% high-carbon ferrochrome gives the flux-cored wire high hardness and wear resistance. The Rockwell hardness HRC of the flux-cored wire of this invention is between 60 and 62.

[0049] ② The manganese and chromium elements provided by electrolytic manganese and 68% high carbon ferrochrome strengthen and toughen the matrix, neutralize and optimize the affinity between the matrix and the reinforcement, reduce the tendency of cracking, and make the flux-cored welding wire have crack-free characteristics.

[0050] ③ The vanadium element provided by 80% ferrovanadium refines the grains and generates a dispersed, high-hardness, non-sharp-angled reinforcing phase. This reinforcing phase possesses excellent thermal stability and wear resistance, giving the flux-cored wire high wear and temperature resistance. Its relative wear resistance is 2.5-2.8 times that of Cr26 high-chromium cast iron, and it maintains a Vickers hardness of HV at 850℃. 10 No less than 530;

[0051] ④ The vanadium provided by 80% ferrovanadium enables the flux-cored welding wire to perform well in molten salt corrosion at 750°C for 48 hours, giving the flux-cored welding wire of the present invention good corrosion resistance and the ability to remain stable in harsh chemical environments.

[0052] ⑤ The preparation method of the flux-cored welding wire of the present invention is simple and convenient to use. It can be directly welded manually or automatically by machine, which is conducive to industrial production. Attached Figure Description

[0053] Figure 1 This is a microhardness test image of a single-layer weld overlay of flux-cored welding wire according to Embodiment 1 of the present invention;

[0054] Figure 2 This is a microhardness test image of a single-layer weld overlay of flux-cored wire according to Embodiment 2 of the present invention. Detailed Implementation

[0055] The invention can be further understood through the specific embodiments given below, but they are not intended to limit the invention.

[0056] Example 1

[0057] This embodiment 1 provides a high-hardness, crack-free flux-cored welding wire. The flux-cored welding wire includes an outer sheath and a flux core filled inside the outer sheath. By weight, the flux core includes the following components: 5.6 parts boron carbide; 3.1 parts 75% ferrosilicon; 0.5 parts electrolytic manganese; 0.3 parts 80% ferrovanadium; 0.3 parts nickel powder; 67.5 parts 68% high-carbon ferrochrome; and 5.7 parts iron powder.

[0058] The powder filling rate inside the core is 30%.

[0059] Based on the above, the total content of boron in the above components is 1.8%, the total content of carbon is 1.5%, the total content of silicon is 1%, the total content of manganese is 0.3%, the total content of vanadium is 0.1%, the total content of nickel is 0.1%, the total content of chromium is 20%, and the total content of iron is 75.2%.

[0060] The preparation method of the high-hardness, crack-free flux-cored welding wire in Example 1 is as follows:

[0061] S1. Add 5.6 parts of boron carbide, 3.1 parts of 75% ferrosilicon, 0.5 parts of electrolytic manganese, 0.3 parts of 80% ferrovanadium, 0.3 parts of nickel powder, 67.5 parts of 68% high-carbon ferrochrome, and 6 parts of iron powder to a dryer at 180°C and dry for 2 hours. Then, put the mixture into a three-dimensional motion mixer at 200°C and mix thoroughly. Finally, put the mixture into a heat preservation box at 140°C and keep it warm. Set aside the resulting core powder.

[0062] S2. Place a low-carbon steel strip with a thickness of 0.4mm and a width of 14mm on a forming machine, and the forming machine rolls the low-carbon steel strip into a U-shaped groove.

[0063] S3. Add flux-cored powder to the U-shaped groove and control the flux filling rate in the flux core to 30%. The forming machine will roll and close the U-shaped groove after adding flux-cored powder and pull it to the diameter of the welding wire to 2.8mm to obtain the flux-cored welding wire. Wipe the welding wire with anhydrous ethanol before pulling.

[0064] S4. Wind the flux-cored wire layer into a disc to obtain a high wear-resistant flux-cored wire finished product for mold steel.

[0065] Upon observation, the flux-cored wire in Example 1 showed no cracks.

[0066] In this embodiment 1, the flux-cored welding wire is deposited in three layers with a thickness of 10mm without cracking.

[0067] Metallographic observation as follows Figure 1 As shown, in this embodiment 1, the single-layer hard phase is dispersed and strengthened, and the microstructure is uniformly distributed.

[0068] The flux-cored wire of Example 1 showed no obvious oxidation or wear after being deposited on the conveyor roller at 1200℃ for 90 days.

[0069] Example 2

[0070] This embodiment 2 provides a high-hardness, crack-free flux-cored welding wire. The flux-cored welding wire includes an outer sheath and a flux core filled inside the outer sheath. By weight, the flux core includes the following components: 7.1 parts boron carbide; 3.7 parts 75% ferrosilicon; 1.0 part electrolytic manganese; 0.6 parts 80% ferrovanadium; 0.5 parts nickel powder; 81 parts 68% high-carbon ferrochrome; and 6.2 parts iron powder.

[0071] The powder filling rate inside the core is 45%.

[0072] Based on the above, the total content of boron in the above components is 2.3%, the total content of carbon is 2%, the total content of silicon is 1.3%, the total content of manganese is 0.5%, the total content of vanadium is 0.2%, the total content of nickel is 0.2%, the total content of chromium is 24%, and the total content of iron is 69.5%.

[0073] The preparation method of the high-hardness, crack-free flux-cored welding wire in Example 2 is as follows:

[0074] S1. Add 7.1 parts of boron carbide, 3.7 parts of 75% ferrosilicon, 1.0 part of electrolytic manganese, 0.6 parts of 80% ferrovanadium, 0.5 parts of nickel powder, 81.0 parts of 68% high-carbon ferrochrome, and 6.2 parts of iron powder to a dryer at 200℃ and dry for 2.5 hours. Then, put the mixture into a three-dimensional motion mixer at 200℃ and mix thoroughly. Finally, put the mixture into a heat preservation box at 150℃ and keep it warm. Set aside the resulting core powder.

[0075] S2. Place a low-carbon steel strip with a thickness of 0.4mm and a width of 14mm on a forming machine, and the forming machine rolls the low-carbon steel strip into a U-shaped groove.

[0076] S3. Add flux-cored powder to the U-shaped groove and control the flux filling rate in the flux core to 45%. The forming machine will roll and close the U-shaped groove after adding flux-cored powder and pull it to the diameter of the welding wire to 2.8mm to obtain the flux-cored welding wire. Wipe the welding wire with anhydrous ethanol before pulling.

[0077] S4. Wind the flux-cored wire layer into a disc to obtain a high wear-resistant flux-cored wire finished product for mold steel.

[0078] Upon observation, the flux-cored welding wire in Example 2 showed no cracks.

[0079] In this embodiment 2, the flux-cored welding wire has a three-layer thickness of 10mm and does not crack.

[0080] Metallographic observation as follows Figure 2 As shown, in this embodiment 2, the single-layer weld hard phase is dispersed and strengthened, and the microstructure is uniformly distributed.

[0081] The flux-cored wire of Example 2 showed no obvious oxidation or wear after being deposited on the conveyor roller at 1200℃ for 90 days.

[0082] Example 3

[0083] This embodiment 3 provides a high-hardness, crack-free flux-cored welding wire. The flux-cored welding wire includes an outer sheath and a flux core filled inside the outer sheath. By weight, the flux core includes the following components: 8.6 parts boron carbide; 4.6 parts 75% ferrosilicon; 1.6 parts electrolytic manganese; 1.2 parts 80% ferrovanadium; 1.0 part nickel powder; 94.5 parts 68% high-carbon ferrochrome; and 6.7 parts iron powder.

[0084] The powder filling rate inside the core is 38%.

[0085] Based on the above, the total content of boron in the above components is 2.8%, the total content of carbon is 2.5%, the total content of silicon is 1.5%, the total content of manganese is 0.8%, the total content of vanadium is 0.4%, the total content of nickel is 0.4%, the total content of chromium is 28%, and the total content of iron is 63.6%.

[0086] The preparation method of the high-hardness, crack-free flux-cored welding wire in Example 3 is as follows:

[0087] S1. Add 8.6 parts of boron carbide, 4.6 parts of 75% ferrosilicon, 1.6 parts of electrolytic manganese, 1.2 parts of 80% ferrovanadium, 1.0 part of nickel powder, 94.5 parts of 68% high-carbon ferrochrome, and 6.5 parts of iron powder to a dryer at 220°C and dry for 3 hours. Then, put the mixture into a three-dimensional motion mixer at 200°C and mix thoroughly. Finally, put the mixture into a heat preservation box at 160°C and keep it warm. Set aside the resulting core powder.

[0088] S2. Place a low-carbon steel strip with a thickness of 0.4mm and a width of 14mm on a forming machine, and the forming machine rolls the low-carbon steel strip into a U-shaped groove.

[0089] S3. Add flux-cored powder to the U-shaped groove and control the flux filling rate in the flux core to 38%. The forming machine will roll and close the U-shaped groove after adding flux-cored powder and draw it to a diameter of 2.8mm to obtain flux-cored welding wire. Wipe the welding wire with anhydrous ethanol before drawing.

[0090] S4. Wind the flux-cored wire layer into a disc to obtain a high wear-resistant flux-cored wire finished product for mold steel.

[0091] Upon observation, the flux-cored welding wire in Example 3 showed no cracks.

[0092] In this embodiment 3, the flux-cored welding wire has a three-layer thickness of 10mm and does not crack.

[0093] The flux-cored wire of Example 3 showed no obvious oxidation or wear after being deposited on the conveyor roller at 1200℃ for 90 days.

[0094] Example 4

[0095] Hardness test

[0096] According to the test methods in GB / T 230.1-2009 Rockwell hardness test and GB / T 4340.1-2009 Vickers hardness test for metallic materials, the flux-cored welding wires prepared in Examples 1-3 were subjected to Rockwell hardness test and Vickers hardness test, respectively. The test results are shown in Table 1 and Table 2, respectively.

[0097] Table 1. Rockwell hardness test results

[0098] test group Example 1 Example 2 Example 3 Rockwell hardness HRC 60.7 61.8 60.3

[0099] Table 2 Vickers hardness test results

[0100] test group Example 1 Example 2 Example 3 850℃ Vickers hardness HRC 536 551 540

[0101] Example 5

[0102] Abrasion resistance test

[0103] The wear resistance of flux-cored welding wires prepared in Examples 1-3 and commercially available Cr26 high-chromium cast iron was tested according to the rubber wheel method of JB / T 7705-1995, the test method for loose abrasive wear. The test results are shown in Table 3.

[0104] Table 3. Test results of wear resistance performance

[0105] test group Initial mass m1 / g Mass after wear m2 / g Wear loss △m / g Example 1 70.323 70.252 0.071 Example 2 70.234 70.159 0.075 Example 3 70.217 70.148 0.069 Cr26 high-chromium cast iron 70.223 70.051 0.172

[0106] Analyze the results in Table 1-3 above:

[0107] As shown in Table 1, the Rockwell hardness of the flux-cored welding wires prepared in Examples 1-3 is between 60 and 62 HRC.

[0108] As shown in Table 2, the Vickers hardness of the flux-cored wires prepared in Examples 1-3 can still be greater than 530 at a temperature of 850°C.

[0109] As shown in Table 3, the wear loss of the flux-cored welding wires prepared in Examples 1-3 is significantly lower than that of Cr26 high-chromium cast iron. In particular, the wear loss of Cr26 high-chromium cast iron is 2.3 times that of the flux-cored welding wire prepared in Example 2 (multiple = wear loss of Cr26 high-chromium cast iron ÷ wear loss of flux-cored welding wire in Example 2).

[0110] Example 6

[0111] High temperature and corrosion resistance test

[0112] The flux-cored welding wires prepared in Examples 1-3 and commercially available OCr25Ni2O heat-resistant stainless steel were used as samples to test their high-temperature corrosion resistance through a molten salt corrosion test. The specific test steps were as follows: ① The sample surface was polished with 1200# sandpaper and placed in a crucible with a diameter of 50 mm; ② 40 g of potassium nitrate + sodium chloride (mixed in a mass ratio of 1:1) was added to the crucible; ③ The crucible was placed in a muffle furnace and kept at 750℃ for 48 h; ④ The samples were removed, ultrasonically cleaned with pure water, and the surface corrosion was observed. The test results are shown in Table 4.

[0113] Table 4. Test results of high temperature resistance and corrosion resistance

[0114]

[0115]

[0116] As shown in Table 4, under the same test conditions, the flux-cored welding wires of Examples 1-3 have better resistance to molten salt corrosion than OCr25Ni2O heat-resistant stainless steel, and can better meet the requirements of high temperature and corrosion resistance.

[0117] The above description is merely an embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A high-hardness, crack-free flux-cored welding wire, the flux-cored welding wire comprising an outer sheath and a flux core filled within the outer sheath, characterized in that, The core comprises the following components in parts by weight: Boron carbide 5.6-8.6 parts; 75% ferrosilicon 3.1-4.6 parts; electrolytic manganese 0.6-1.6 parts; 80% ferrovanadium 0.3-1.2 parts; nickel powder 0.3-1.0 parts; 68% high-carbon ferrochrome 67.5-94.5 parts; iron powder 6-6.5 parts; The powder filling rate within the core is 30-45%. The chemical composition of the fused metal of the core, by weight percentage, includes the following components: Boron: 1.8–2.8%; Carbon: 1.5–2.5%; Silicon: 1–1.5%; Manganese: 0.3–0.8%; Vanadium: 0.1–0.4%; Nickel: 0.1–0.4%; Chromium: 20–28%, with the balance being iron.

2. The high-hardness, crack-free flux-cored welding wire according to claim 1, characterized in that, The core comprises the following components in parts by weight: Boron carbide 7.1 parts; 75% ferrosilicon 3.7 parts; electrolytic manganese 1.0 part; 80% ferrovanadium 0.6 parts; nickel powder 0.5 parts; 68% high-carbon ferrochrome 81 parts; iron powder 6.2 parts.

3. The high-hardness, crack-free flux-cored welding wire according to claim 1, characterized in that, The powder filling rate of the core is 45%.

4. A method for preparing a high-hardness, crack-free flux-cored welding wire as described in any one of claims 1 to 3, characterized in that, The preparation method includes the following steps: S1. Add boron carbide, 75% ferrosilicon, electrolytic manganese, 80% ferrovanadium, nickel powder, 68% high-carbon ferrochrome and iron powder to a dryer at 180-220℃ and dry for 2-3 hours. Then put the mixture into a three-dimensional motion mixer at 200℃ and mix thoroughly. Then put the mixture into a heat preservation box at 140-160℃ and keep it warm. Set aside the obtained core powder. S2. Place the outer skin on the forming machine, and the forming machine rolls the outer skin steel strip into a U-shaped groove; S3. Add the core powder to the U-shaped groove and control the powder filling rate in the core to be 30-45%. The forming machine rolls and closes the U-shaped groove after adding the core powder and pulls it to obtain the core welding wire.

5. The method for preparing high-hardness, crack-free flux-cored welding wire according to claim 4, characterized in that, The temperature of the dryer is 200℃, and the temperature of the insulation box is 150℃.

6. The method for preparing high-hardness, crack-free flux-cored welding wire according to claim 5, characterized in that, The outer sheath is made of low-carbon steel strip.

7. The method for preparing high-hardness, crack-free flux-cored welding wire according to claim 6, characterized in that, The low-carbon steel strip has a thickness of 0.4 mm and a width of 14 mm.

8. The method for preparing high-hardness, crack-free flux-cored welding wire according to claim 4, characterized in that, In step S3, the welding wire is wiped with anhydrous ethanol before drawing.

9. The method for preparing high-hardness, crack-free flux-cored welding wire according to claim 7, characterized in that, The diameter of the flux-cored welding wire obtained by drawing is 2.8 mm.

Images