Welding rod for cold stamping die surfacing and manufacturing method thereof

Abstract

The present invention provides a welding rod for cold die surfacing, comprising a welding core and a coating. The coating is evenly arranged on the outer periphery of the welding core. The coating is composed of the following raw materials in percentage by mass: 31-33% high-carbon ferrochromium, 15-17% tungsten carbide, 9-11% tungsten powder, 7-8.5% marble, 5-7% ferrovanadium, 4-5.5% ferromolybdenum, 3-4.5% ferroniobium, 3-4% phlogopite, 2-4% manganese silicon alloy, 2-4% ferrosilicon, 2-5% boron carbide, 1-2.5% fluorite, 1-2.5% high-carbon ferromanganese, 0.5-1.2% graphite, and 1-2.5% ferrotitanium. The welding rod has high anti-porosity performance, strong weld hardness after welding, a smooth surface, good pressure-coating properties, high hardness, and good wear resistance and toughness.

Description

Technical Field

[0001] The invention relates to the field of welding materials, and in particular to a welding rod for cold stamping die surfacing and a manufacturing method thereof. Background Art

[0002] Molds are a fundamental component of industrial production processes and are widely used in industries such as machinery, automobiles, electronics, and home appliances. Over 80% of product parts are produced using molds, and cold stamping dies represent the largest portion of all molds, accounting for over 60% of the total mold market. Therefore, the repair of cold stamping dies during use is highly worthy of research. Cold stamping dies, also known as cold stamping dies, are specialized tools typically mounted on a press, applying a deforming force to a sheet of material placed within them at room temperature, thereby deforming the product to a desired shape, size, and performance. Based on the nature of the process, they can be categorized as blanking dies, drawing dies, bending dies, and forming dies. Based on the degree of process integration, they can be divided into single-process dies, compound dies, and continuous dies. Stamping dies are subject to impact, vibration, friction, high-pressure tensile forces, bending and torsion loads, and even high temperatures (cold extrusion). These complex operating conditions are prone to wear, fatigue, fracture, and deformation. The material requirements for mold working parts are higher than those for ordinary parts. These parts must possess the following properties: 1. High wear resistance and hardness to ensure smooth blanking. 2. High strength, hardness, and wear resistance to prevent breakage due to impact. 3. Certain strength and toughness. Therefore, the cold stamping die surfacing welding rods used for cold stamping die repair also need to have the same characteristics, but the current welding rods do not have the corresponding performance. Summary of the Invention

[0003] In view of the above shortcomings of the prior art, the present invention provides a welding rod and a manufacturing method for cold die cladding to improve the technical problems in the prior art of the welding rod cladding metal being not wear-resistant, having low hardness, low strength and insufficient toughness.

[0004] To achieve the above and other related purposes, the present invention provides a welding rod for cold die surfacing, comprising: a welding core and a coating, wherein the coating is evenly arranged on the periphery of the welding core, and the coating is composed of the following raw materials in the following mass percentages:

[0005] High carbon ferrochrome 31-33%, tungsten carbide 15-17%, tungsten powder 9-11%, marble 7-8.5%, ferrovanadium 5-7%, ferromolybdenum 4-5.5%, ferroniobium 3-4.5%, phlogopite 3-4%, manganese silicon alloy 2-4%, ferrosilicon 2-4%, boron carbide 2-5%, fluorite 1-2.5%, high carbon ferromanganese 1-2.5%, graphite 0.5-1.2%, ferrotitanium 1-2.5%.

[0006] In one example of the present invention, the chromium content in high-carbon ferrochrome is 60-68 wt%; the tungsten content in tungsten powder is greater than or equal to 99 wt%; the calcium carbonate content in marble is greater than or equal to 96 wt%; the vanadium content in ferrovanadium is 50-55 wt%; the molybdenum content in ferromolybdenum is 55-60 wt%; the niobium content in ferroniobium is 50-60 wt%; the manganese content in manganese-silicon alloy is 62-67 wt% and the silicon content is 20-23 wt%; the silicon content in ferrosilicon is 42-48 wt%; and the manganese content in high-carbon ferromanganese is 65-75 wt%.

[0007] In one embodiment of the present invention, the particle size of the graphite in the coating is 80-120 mesh.

[0008] In one embodiment of the present invention, the particle size of the raw materials in the coating except graphite is 40-80 mesh.

[0009] In one example of the present invention, the diameter of the welding core ranges from 2.5 to 4.0 mm, and the welding core is an H08 steel core.

[0010] In one embodiment of the present invention, a method for manufacturing a welding rod as described above is provided, comprising:

[0011] Prepare the medicine coating;

[0012] Adding a binder to the coating and stirring evenly to form a coating mixture;

[0013] The coating mixture is pressed onto the surface of the welding core and dried to obtain a welding rod.

[0014] In one example of the present invention, the adhesive is a water glass adhesive, and the mass of the adhesive is 20-23% of the total mass of the coating mixture.

[0015] In one embodiment of the present invention, the weight of the coating mixture after drying accounts for 45-50% of the total weight of the welding rod.

[0016] In one embodiment of the present invention, the pressure of applying the coating mixture to the welding core is 8-12 MPa.

[0017] In one embodiment of the present invention, the coating mixture is dried at a temperature of 350-380° C., and the coating mixture is dried for 1-2 hours.

[0018] The present invention provides a welding rod for cold die hardfacing and a manufacturing method. Marble is added to the flux coating to generate slag and gas at arc temperatures, improving the rod's anti-porosity properties. High-carbon ferromanganese, high-carbon ferrochrome, ferrovanadium, ferromolybdenum, tungsten carbide, tungsten powder, and graphite are added to infiltrate the weld seam with an alloy. The chromium, molybdenum, tungsten, and carbon elements increase weld hardness, while molybdenum and vanadium refine the deposited metal structure and improve weld toughness. The cold die hardfacing welding rod produced by the present invention has a smooth surface, good press-coatability, high hardness, and excellent wear resistance and toughness. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 Flowchart of a welding rod manufacturing method according to one embodiment of the present invention. DETAILED DESCRIPTION

[0021] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following examples and the features in the examples can be combined with each other unless they conflict. It should also be understood that the terms used in the examples of the present invention are for the purpose of describing specific embodiments, not for the purpose of limiting the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0022] When numerical ranges are given in the examples, it should be understood that unless otherwise specified herein, both endpoints of each numerical range and any value between the two endpoints may be used. Unless otherwise defined, all technical and scientific terms used herein are consistent with the prior art as understood by those skilled in the art and the description of the present invention. Any prior art methods, devices, and materials similar or equivalent to those described in the examples of the present invention may also be used to implement the present invention.

[0023] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0024] See also Figure 1 The present invention provides a welding rod for cold die surfacing and a manufacturing method. Marble is added to the flux coating to generate slag and gas at the arc temperature, thereby improving the anti-porosity performance of the welding rod. High-carbon ferromanganese, high-carbon ferrochrome, ferrovanadium, ferromolybdenum, tungsten carbide, tungsten powder, and graphite are added to the flux coating to infiltrate the weld with alloy. Among them, chromium, molybdenum, tungsten, and carbon can improve the hardness of the weld, and molybdenum and vanadium can refine the structure of the deposited metal and improve the toughness of the weld. The welding rod of the present invention has a smooth surface, good pressure coating properties, strong hardness, good wear resistance and toughness, and can effectively improve the technical problems of the welding rod welding repair area in the prior art, such as poor wear resistance, low hardness, low strength, and insufficient toughness.

[0025] The welding rod for cold die surfacing comprises: a welding core and a flux coating, wherein the flux coating is evenly arranged on the outer periphery of the welding core, and the flux coating comprises the following raw materials in percentage by mass: 31-33% high-carbon ferrochrome, 15-17% tungsten carbide, 9-11% tungsten powder, 7-8.5% marble, 5-7% ferrovanadium, 4-5.5% ferromolybdenum, 3-4.5% ferroniobium, 3-4% phlogopite, 2-4% manganese silicon alloy, 2-4% ferrosilicon, 2-5% boron carbide, 1-2.5% fluorite, 1-2.5% high-carbon ferromanganese, 0.5-1.2% graphite, and 1-2.5% ferrotitanium.

[0026] The mass percentage and function of each component of the coating are detailed as follows:

[0027] High-carbon ferrochrome: The chromium content in high-carbon ferrochrome is 60-68% by weight. Its primary function is alloying, and adding a certain amount can improve weld hardness. The weight percentage of high-carbon ferrochrome in the coating is 31-33%. For example, the weight percentage of high-carbon ferrochrome can be 31%, 32%, or 33%, or any other value within this range.

[0028] Tungsten carbide: The tungsten content is greater than or equal to 96% by weight. Tungsten carbide's primary function is alloying. It increases tempering stability, red hardness, hot strength, and wear resistance due to the formation of carbides. It also reduces the steel's overheating sensitivity, increases hardenability, and improves hardness and machinability. The weight percentage of tungsten carbide in the coating is 15-17%, for example, 15%, 15.5%, or 17%, or any other value within this range.

[0029] Marble: Marble contains 96% or more calcium carbonate by weight. Marble primarily serves as a gasifier and slag generator. During welding, calcium carbonate decomposes into calcium oxide and carbon dioxide gas. The generated carbon dioxide maintains an inert atmosphere in the weld pool. The weight percentage of marble in the coating is 7-8.5%, for example, 7%, 7.5%, or 8.5%, among other values ​​within this range.

[0030] Fluorite: Fluorite contains 95% or greater calcium fluoride. Fluorite primarily serves as a slag-forming agent. During welding, calcium deoxidizes and desulfurizes, while fluorine removes hydrogen. Therefore, fluorite purifies the deposited metal. The weight percentage of fluorite in the flux coating is 1-2.5%. For example, the weight percentage of fluorite can be 1%, 2%, or 2.5%, or any other value within these ranges.

[0031] Graphite: Graphite's primary function is to transfer carbon to the weld metal, thereby increasing its hardness. Graphite also deoxidizes and improves press-coatability. However, excessive additions can increase spatter. The weight percentage of graphite in the coating is 0.5-1.2%. For example, the weight percentage can be 0.5%, 0.8%, or 1.2%, or any other value within this range.

[0032] High-carbon ferromanganese: The manganese content in high-carbon ferromanganese is 65-75% by weight. High-carbon ferromanganese is primarily used as a deoxidizer, alloying agent, and desulfurizer. Excessive amounts can increase spatter. The weight percentage of high-carbon ferromanganese in the coating is 1-2.5%. For example, the weight percentage of high-carbon ferromanganese can be 1%, 1.5%, or 2.5%, or any other value within this range.

[0033] Ferrosilicon: Ferrosilicon contains 42-48% silicon by weight. It is primarily used as a deoxidizer and alloying agent. Excessive amounts can increase spatter and reduce toughness. The weight percentage of ferrosilicon in the coating is 2-4%. For example, the weight percentage can be 2%, 2.5%, or 4%, among other values ​​within this range.

[0034] Ferrotitanium: Ferrotitanium is primarily used as a deoxidizer. Excessive amounts can increase spatter. The weight percentage of ferrotitanium in the coating is 1-2.5%. For example, the weight percentage of ferrotitanium can be 1%, 1.5%, or 2.5%, or any other value within the above range.

[0035] Ferromolybdenum: Ferromolybdenum contains 55-60% molybdenum by weight. Its primary function is to serve as a transition alloying element to the deposited metal. Molybdenum improves the hardenability of the weld metal and its corrosion resistance, refines the grain size, and enhances the hardenability of the steel. The weight percentage of ferromolybdenum in the coating is 4-5.5%. For example, the weight percentage of ferrotitanium can be 4%, 5%, or 5.5%, or any other value within this range.

[0036] Ferrovanadium: The vanadium content in ferrovanadium is 50-55% by weight. Its primary use is in alloying. Vanadium improves weld wear resistance, refines grain size, and enhances steel's impact toughness. However, excessive vanadium can reduce wear resistance. The weight percentage of ferrovanadium in the coating is 5-7%, for example, 5%, 6%, or 7%, among other values ​​within this range.

[0037] Ferroniobium: Ferroniobium contains 50-60% niobium by weight. Its primary function is to transition alloying elements into the weld metal, imparting certain special properties to the weld metal. The weight percentage of ferroniobium in the coating is 3-4.5%. For example, the weight percentage of ferroniobium can be 3%, 4%, or 4.5%, or any other value within this range.

[0038] Tungsten powder: Tungsten content is greater than or equal to 99% by weight. Tungsten powder is primarily used for alloying. Tungsten increases tempering stability, hot hardness, and heat resistance due to the formation of carbides, while also improving wear resistance by reducing steel's overheating sensitivity, increasing hardenability, and enhancing hardness and machinability. The weight percentage of tungsten powder in the coating is 9-11%. For example, the weight percentage of molybdenum powder can be 9%, 9.5%, or 11%, or any other value within this range.

[0039] Phlogopite: Phlogopite contains 42-55% silica by weight. Its primary function is to enhance the coating's plasticity, fluidity, and lubricity, improve coating pressure-coating performance, enhance welding rod pressure-coating quality, and reduce electrode eccentricity. The weight percentage of phlogopite in the coating is 3-4%. For example, the weight percentage of phlogopite can be 3%, 3.8%, or 4%, or any other value within these ranges.

[0040] Manganese-silicon alloy: The manganese content in manganese-silicon alloy is 62-67% by weight, and the silicon content is 20-23%. The main function of manganese-silicon alloy is a deoxidizer, improving the properties of the weld metal and reducing the oxygen content in the weld metal. The weight proportion of manganese-silicon alloy in the coating is 2-4%. For example, the weight proportion of manganese-silicon alloy can be any value within the above range, such as 2%, 3%, or 4%.

[0041] Boron carbide: The boron carbide content is greater than or equal to 96% by weight. Boron carbide primarily acts as an arc stabilizer, maintaining stable arc combustion, arc concentration, and a certain degree of arc rigidity during welding. The weight percentage of boron carbide in the flux coating is 2-5%, for example, the weight percentage of boron carbide can be any value within the above range, such as 2%, 3.2%, or 5%.

[0042] In one embodiment of the present invention, the particle size of the graphite in the coating is 80 to 120 mesh. The particle size of the graphite in the coating can be any value between 80 and 120 mesh, for example, the particle size of the graphite in the coating is 80 mesh, 99 mesh, or 120 mesh. The particle size of the raw materials other than graphite in the coating is 40 to 80 mesh. The particle size of the raw materials other than graphite in the coating can be any value between 40 and 80 mesh, for example, the particle size of the raw materials other than graphite in the coating is 40 mesh, 66 mesh, or 80 mesh. Mesh size refers to the size of the raw material particles, and a larger mesh number indicates finer particles.

[0043] In one embodiment of the present invention, the diameter of the welding core ranges from 2.5 to 4.0 mm. The diameter of the welding core can be any value between 2.5 and 4.0 mm, for example, the diameter of the welding core is 2.5 mm, 3.3 mm, or 4.0 mm. The welding core is H08 steel core.

[0044] In one embodiment of the present invention, a method for manufacturing the welding rod as described in any one of the above items is further provided, comprising:

[0045] Step S1, preparing the coating. Specifically, the coating is prepared by mixing high-carbon ferrochrome 31-33%, tungsten carbide 15-17%, tungsten powder 9-11%, marble 7-8.5%, ferrovanadium 5-7%, ferromolybdenum 4-5.5%, ferroniobium 3-4.5%, phlogopite 3-4%, manganese silicon alloy 2-4%, ferrosilicon 2-4%, boron carbide 2-5%, fluorite 1-2.5%, high-carbon ferromanganese 1-2.5%, graphite 0.5-1.2%, and ferrotitanium 1-2.5%.

[0046] In step S2, a binder is added to the coating and stirred to form a coating mixture. The binder is a water glass binder. The modulus of the water glass binder is the ratio of sodium oxide to silicon dioxide in the water glass binder. The modulus of the water glass binder is 2.8 to 3.1. For example, the modulus of the binder is 2.8, 3, or 3.1. The mass of the binder is 20 to 23% of the total mass of the coating mixture.

[0047] In step S3, the coating mixture is press-coated onto the surface of the welding core and dried to obtain a welding rod. The dried coating mixture accounts for 45-50% of the total weight of the welding rod. The coating mixture is dried at a temperature of 350-380°C for 1-2 hours. The coating mixture is press-coated onto the welding core at a pressure of 8-12 MPa.

[0048] In one embodiment of the present invention, the mass of the binder can be any value between 20% and 23% of the total mass of the coating, for example, the mass of the binder can be 20%, 22.5% or 23% of the total mass of the coating. The weight of the coating mixture after drying can account for any value between 45% and 50% of the total weight of the welding rod, for example, the weight of the coating mixture after drying can account for 45%, 48.7% or 50% of the total weight of the welding rod. The drying temperature of the coating mixture can be any value between 350 and 380°C, for example, the drying temperature of the coating mixture is 350°C, 366.9°C or 380°C. The drying time of the coating mixture is any value between 1 and 2 hours, for example, the drying time of the coating mixture is 1 hour, 1.35 hours or 2 hours. The pressure of the coating mixture applied to the welding core is any value between 8 and 12 MPa, for example, 8 MPa, 9 MPa or 12 MPa.

[0049] The present invention is described in detail below through some specific examples. The drugs used in the following examples can be obtained through common commercial means.

[0050] Example 1:

[0051] The cold stamping die surfacing electrode of this embodiment includes a welding core and a coating, wherein the coating includes the following components and the weight proportions of each component are: 31% high carbon ferrochrome, 15% tungsten carbide, 11% tungsten powder, 8% marble, 6% ferrovanadium, 4% ferromolybdenum, 4% ferroniobium, 3% phlogopite, 4% manganese silicon alloy, 3% ferrosilicon, 4% boron carbide, 2% fluorite, 2% high carbon ferromanganese, 1% graphite, and 2% ferrotitanium.

[0052] During preparation, an H08A welding core with a diameter of 2.5 mm was selected, and a water glass binder accounting for 23% of the total mass of the dry powder mixture was added to the above-mentioned coating. The mixture was stirred and mixed evenly to form a coating mixture. The coating mixture was press-coated on the surface of the welding core at 8 MPa and dried at 350°C for 1 hour to obtain a cold stamping die surfacing electrode. The mass of the coating mixture after drying accounted for 45% of the total mass of the cold stamping die surfacing electrode.

[0053] Example 2:

[0054] The cold stamping die surfacing electrode of this embodiment includes a welding core and a coating, wherein the coating includes the following components and the weight proportions of each component are: 33% high carbon ferrochrome, 17% tungsten carbide, 9% tungsten powder, 7% marble, 7% ferrovanadium, 5% ferromolybdenum, 3% ferroniobium, 3.5% phlogopite, 3% manganese silicon alloy, 4% ferrosilicon, 5% boron carbide, 1% fluorite, 1% high carbon ferromanganese, 0.5% graphite, and 1% ferrotitanium.

[0055] During preparation, an H08A welding core with a diameter of 3.2 mm was selected, and a water glass binder accounting for 22% of the total mass of the dry powder mixture was added to the above-mentioned coating. The mixture was stirred and mixed evenly to form a coating mixture. The coating mixture was press-coated on the surface of the welding core at 12 MPa and dried at 360°C for 1.5 hours to obtain a cold stamping die surfacing electrode. The mass of the coating mixture after drying accounted for 47% of the total mass of the cold stamping die surfacing electrode.

[0056] Example 3:

[0057] The cold stamping die surfacing electrode of this embodiment includes a welding core and a coating, wherein the coating includes the following components and the weight proportions of each component are: 32% high carbon ferrochrome, 16% tungsten carbide, 10% tungsten powder, 8.5% marble, 5% ferrovanadium, 5.5% ferromolybdenum, 4.5% ferroniobium, 4% phlogopite, 2% manganese silicon alloy, 2% ferrosilicon, 2% boron carbide, 2.5% fluorite, 2.5% high carbon ferromanganese, 1.2% graphite, and 2.5% ferrotitanium.

[0058] During preparation, a H08A welding core with a diameter of 4 mm was selected, and a water glass binder accounting for 20% of the total mass of the dry powder mixture was added to the above-mentioned coating. The mixture was stirred and mixed evenly to form a coating mixture. The coating mixture was press-coated on the surface of the welding core at 10 MPa and dried at 380°C for 2 hours to obtain a cold stamping die surfacing electrode. The mass of the coating mixture after drying accounted for 50% of the total mass of the cold stamping die surfacing electrode.

[0059] Various welding tests were conducted on the welding rods provided in the above-mentioned Examples 1, 2 and 3 according to relevant standards and specifications. The chemical composition of the deposited metal is shown in Table 1, and the hardness test is shown in Table 2:

[0060] Table 1 Chemical composition of deposited metal

[0061]

[0062] Table 2 Welding performance three-point hardness test

[0063]

[0064] The test results of Examples 1 to 3 show that the cold stamping die surfacing electrode of the present invention has good welding processability, good hardness, wear resistance and crack resistance, and the HRC hardness of the deposited metal is uniform and stable.

[0065] The present invention discloses a welding rod and manufacturing method for cold die hardfacing. The addition of marble to the flux coating acts as a slag and gas generator at arc temperatures, improving the rod's anti-porosity properties. High-carbon ferromanganese, high-carbon ferrochromium, ferrovanadium, ferromolybdenum, ferrotitanium, tungsten powder, and graphite are then added to the weld for alloying. The chromium, molybdenum, tungsten, and carbon elements increase weld hardness, while the molybdenum and vanadium elements refine the deposited metal structure and improve weld toughness. The cold die hardfacing welding rod produced by the present invention has a smooth surface, excellent press-coatability, strong hardenability and hardenability, as well as good wear resistance and dimensional stability. Therefore, the present invention effectively overcomes several practical problems in the prior art and thus has high utility and practical significance. The above-described embodiments are merely illustrative of the principles and efficacy of the present invention and are not intended to limit the invention. Anyone skilled in the art may modify or alter the above-described embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A welding rod for cold die surfacing, characterized in that: include: A welding core and a coating, wherein the coating is evenly arranged on the periphery of the welding core, and the coating is composed of the following raw materials in the following mass percentages: High carbon ferrochrome 31-33%, tungsten carbide 15-17%, tungsten powder 9-11%, marble 7-8.5%, ferrovanadium 5-7%, ferromolybdenum 4-5.5%, ferroniobium 3-4.5%, phlogopite 3-4%, manganese silicon alloy 2-4%, ferrosilicon 2-4%, boron carbide 2-5%, fluorite 1-2.5%, high carbon ferromanganese 1-2.5%, graphite 0.5-1.2%, ferrotitanium 1-2.5%.

2. The welding rod according to claim 1, characterized in that The chromium content of the high-carbon ferrochrome is 60-68wt%; the tungsten content of the tungsten powder is greater than or equal to 99wt%; the calcium carbonate content of the marble is greater than or equal to 96wt%; the vanadium content of the ferrovanadium is 50-55wt%; the molybdenum content of the ferromolybdenum is 55-60wt%; the niobium content of the ferroniobium is 50-60wt%; the manganese content of the manganese silicon alloy is 62-67wt%, and the silicon content is 20-23wt%; the silicon content of the ferrosilicon is 42-48wt%; and the manganese content of the high-carbon ferromanganese is 65-75wt%.

3. The welding rod according to claim 1, characterized in that The particle size of the graphite in the medicine coating is 80 to 120 meshes.

4. The welding rod according to claim 1, characterized in that The particle size of the raw materials in the coating except the graphite is 40 to 80 meshes.

5. The welding rod according to claim 1, characterized in that The diameter of the welding core is in the range of 2.5 to 4.0 mm, and the welding core is an H08 steel core.

6. A method for manufacturing a welding rod according to any one of claims 1 to 5, characterized in that: include: Prepare the medicine coating; Adding a binder to the coating and stirring evenly to form a coating mixture; The coating mixture is press-coated on the surface of the welding core and dried to obtain the welding rod.

7. The production method according to claim 6, characterized in that: The adhesive is a water glass adhesive, and the mass of the adhesive is 20-23% of the total mass of the coating mixture.

8. The manufacturing method according to claim 6, characterized in that: The weight of the coating mixture after drying accounts for 45-50% of the total weight of the welding rod.

9. The manufacturing method according to claim 6, characterized in that: The pressure of applying the coating mixture to the welding core is 8-12 MPa.

10. The manufacturing method according to claim 6, characterized in that: The coating mixture is dried at a temperature of 350 to 380° C., and the coating mixture is dried for 1 to 2 hours.

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