Coating for all-position vertical downward welding, welding rod and preparation method

Abstract

The invention discloses a coating for all-position vertical downward welding, a welding rod and a preparation method. The coating comprises the following raw materials: a component A and a component B, wherein the component A comprises the following raw materials in percentage by weight: 40%-50% of rutile, 1%-3% of titanium dioxide, 5%-9% of marble, 5%-9% of olivine, 6%-10% of mica, 7%-15% of feldspar, 3%-6% of sepiolite, 3%-6% of talcum powder, 2%-5% of wollastonite, 3%-6% of starch, 3%-6% of microcrystalline fiber and 7%-10% of medium carbon ferromanganese; and the component B is a binder. The components are compounded to form the coating for all-position vertical downward welding, the coating is used for preparing the welding rod for all-position vertical downward welding, the yield is high (larger than 98%), and the excellent flat welding performance and the excellent vertical downward welding performance are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of welding materials, and in particular to a flux coating, a welding rod and a preparation method for all-position vertical downward welding. Background Art

[0002] At present, domestic common carbon steel welding rods J421 and MT-12 have lower cost and better mechanical properties, but they cannot be used for vertical downward welding, and are called low-end products for export. E6013 welding rods, which have equivalent mechanical properties to J421 and MT-12, can be used for flat welding, all-position welding, and vertical downward welding, such as Japan Kobelco's RB-26 welding rods and Sweden Isa's OK46.00 welding rods, are sold at a price of 400-600 USD / ton higher than our current low-end products for export in the Southeast Asian market. The market situation in the Middle East, Africa and South America is the same. The formula cost (coating raw material cost) of E6013 welding rods that can be used for vertical downward welding is about 150 USD / ton higher than that of MT-12 welding rods, but the export price is more than 400 USD / ton higher than that of MT-12 welding rods, so the export profit per ton of welding rods can increase by more than 250 USD. This type of welding rod is currently the most widely used welding rod in developing countries around the world. It has great export potential and is worth focusing on in order to open up export markets.

[0003] E6013 all-position vertical downward welding rod is a rutile type welding rod, which can be used for welding various low-carbon steel structures. According to the use survey in Southeast Asia, the Middle East and South America, 70% of this welding rod is still used for flat welding and flat fillet welding, and 30% is used for flat plate butt vertical downward welding and fillet vertical downward welding. Therefore, it must have excellent flat welding performance and excellent vertical downward welding performance. It is often difficult to take both into account. Summary of the invention

[0004] The purpose of the present invention is to overcome the above technical deficiencies, and to propose a flux coating, welding rod and preparation method for all-position vertical downward welding, so as to solve the technical problem in the prior art that the preparation of welding rods that can take into account both excellent flat welding performance and vertical downward welding performance is difficult.

[0005] In a first aspect, the present invention provides a flux coating for all-position vertical downward welding, wherein the raw materials include component A and component B; wherein the raw materials of component A, by weight percentage, include: 40%-50% rutile, 1%-3% titanium dioxide, 5%-9% marble, 5%-9% olivine, 6%-10% mica, 7%-15% feldspar, 3%-6% sepiolite, 3%-6% talc, 2%-5% wollastonite, 3%-6% starch, 3%-6% microcrystalline fiber, and 7%-10% medium carbon ferromanganese; component B is a binder.

[0006] In a second aspect, the present invention provides a welding rod for all-position vertical downward welding, comprising a welding core and a flux coating covering the surface of the welding core; wherein the flux coating is the flux coating for all-position vertical downward welding provided in the first aspect of the present invention.

[0007] In a third aspect, the present invention provides a method for preparing a welding rod for all-position vertical downward welding, comprising the following steps: The raw materials of the flux for all-position vertical downward welding are mixed evenly and then coated on the surface of the welding core, and then dried to obtain the welding rod for all-position vertical downward welding.

[0008] Compared with the prior art, the beneficial effects of the present invention include: The present invention compounds the above components into a flux coating for all-position vertical downward welding, and uses the flux coating to prepare welding rods for all-position vertical downward welding, which not only has a high yield rate (>98%), but also has excellent flat welding performance and excellent vertical downward welding performance. DETAILED DESCRIPTION

[0009] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. 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.

[0010] The present invention adjusts and improves the coating formula and material selection of the E6013 welding rod. The biggest difficulty in the research of the formula of the E6013 all-position vertical downward welding rod is that it requires both good flat welding performance and good vertical downward performance. It is not a special vertical downward welding rod, but a general welding rod. Vertical downward welding generally requires a large slag viscosity, while flat welding requires good slag wettability, so that the weld formation can have delicate and beautiful textures, and these two are often difficult to take into account. Therefore, the formula technical idea of ​​this welding rod is different from that of the special vertical downward welding rod, and also different from the ordinary J421 welding rod.

[0011] Based on this, the present invention is proposed.

[0012] In a first aspect, the present invention provides a flux coating for all-position vertical downward welding, wherein the raw materials include component A and component B; wherein the raw materials of component A, by weight percentage, include: 40%-50% rutile, 1%-3% titanium dioxide, 5%-9% marble, 5%-9% olivine, 6%-10% mica, 7%-15% feldspar, 3%-6% sepiolite, 3%-6% talc, 2%-5% wollastonite, 3%-6% starch, 3%-6% microcrystalline fiber, and 7%-10% medium carbon ferromanganese; component B is a binder.

[0013] In this application, the functions of each component and the amount added are as follows: Rutile: weak oxidizing property, good thermal slag removal, stable arc, making metal transition in fine mist, adjusting slag viscosity and surface tension, forming ultra-short slag, ensuring that the molten pool solidifies in a short time during all-position welding. However, if the amount added is too low, the improvement effect on all-position welding is not significant; if the amount added is too high, the viscosity of the liquid molten pool increases, the fluidity becomes worse, which is not conducive to weld formation.

[0014] Titanium dioxide: The crystal structure and melting point are somewhat different from rutile, which can make the slag form short slag in a wider temperature range, ensuring the feasibility of all-position welding; at the same time, titanium dioxide has fine particles and certain lubricity. Adding a proper amount can effectively improve the electrode pressure coating performance and electrode surface quality. However, if the amount added is too low, the powder fluidity will be poor, affecting the pressure coating performance of the coating. If the amount added is too high, it will increase the cost.

[0015] Marble: As a slag-forming agent and gas-forming agent, it can improve the arc blowing force and arc stability. However, if the amount added is too low, it will cause pores in the weld; if the amount added is too high, it will increase the oxidation of the arc atmosphere, which is not conducive to the loss of oxygen ions in TiO2 and the conductivity of the electrode sleeve.

[0016] Olivine: It can increase the oxidizability of slag, causing the liquid metal and slag to produce an interface reaction at high temperature, reducing the interfacial tension, and facilitating the balance of flat welding and vertical downward welding performance; in addition, it is also beneficial to improve the pressure coating performance of the welding rod.

[0017] Mica: As a slag-forming agent, it can also improve the pressure coating performance of welding rods. However, if the amount added is too low, it will make pressure coating difficult and the yield rate will decrease; if the amount added is too high, it will lead to excessive amorphous phase SiO2 in the slag, reduce the proportion of crystal phase, and it will be difficult to obtain short slag.

[0018] Feldspar: It can significantly improve the arc stability effect. However, if the amount added is too low, the arc will be unstable; if the amount added is too high, SiO2 and Al2O3 in the slag will increase, and the arc stabilization effect will no longer increase.

[0019] Sepiolite: It can improve the pressure-coating performance of welding rods, and the crystal water it contains can significantly improve the arc blowing force of welding rods. However, if the amount added is too low, it will not be conducive to improving the pressure-coating performance and arc blowing force; if the amount added is too high, it will increase welding spatter.

[0020] Talc: It can improve the pressure coating performance of welding rod production and is also a slag forming agent. However, if the amount added is too low, it will not be conducive to improving the pressure coating performance; if the amount added is too high, it will have an adverse effect on the weld formation.

[0021] The invention uses olivine, sepiolite and talcum powder in combination, so as to improve the pressure coating performance of the formula, produce welding rods quickly, have stable eccentricity, and have a welding rod finished product rate of more than 98%, with high production efficiency.

[0022] Wollastonite: It has physical properties such as small linear expansion coefficient and narrow crystal phase transition temperature range; it can also increase the permeability of slag.

[0023] Microcrystalline fiber: It is an organic substance with a high carbonization point. It decomposes a large amount of gas under high temperature, but it is not easy to carbonize, which enhances the protection effect, has strong arc blowing force, has stiffness, and has a deep penetration, which enables the electrode to weld vertically downward. At the same time, the addition of microcrystalline fiber improves the pressure coating of the electrode and improves the arc re-striking of the electrode. However, if the amount added is too low, the force will be slightly insufficient, especially in the vertical 90° downward operation process. If the amount added is too high, it will cause excessive welding blowing force, affecting the welding operability.

[0024] Starch: It is also an organic substance, and its carbonization point is slightly lower than that of microcrystalline fiber.

[0025] The invention uses microcrystalline fiber and starch in combination, utilizes different carbonization points of organic matter to make the arc blowing force continuous, and optimizes the arc softness by reasonable proportion of the two organic matters.

[0026] Medium carbon ferromanganese: as a deoxidizing and desulfurizing agent, it ensures the mechanical properties of the weld. However, if the amount added is too low, the toughness of the weld will decrease; if the amount added is too high, it will lead to excessive deoxidation and easy formation of pores in the weld.

[0027] Binder: Promote the solidification of raw materials.

[0028] In this embodiment, the raw materials of component A include, by weight percentage: 40%-45% rutile, 1%-3% titanium dioxide, 5%-7% marble, 5%-7% olivine, 6%-9% mica, 7%-12% feldspar, 3%-5% sepiolite, 3%-5% talc, 2%-5% wollastonite, 3%-5% starch, 3%-5% microcrystalline fiber, and 7%-8% medium carbon ferromanganese.

[0029] In this embodiment, the binder is water glass.

[0030] In some specific embodiments of the present invention, the binder is potassium-sodium mixed water glass, and the mass ratio of potassium to sodium is 2:1, the molar ratio (modulus M) is 2.9-3.0, and the Baume degree Be is 42-45 degrees.

[0031] In this embodiment, the mass ratio of component A to component B is 100:(23-25).

[0032] In a second aspect, the present invention provides a welding rod for all-position vertical downward welding, comprising a welding core and a flux coating covering the surface of the welding core; wherein the flux coating is the flux coating for all-position vertical downward welding provided in the first aspect of the present invention.

[0033] In this embodiment, the welding core is a H08A carbon steel welding core.

[0034] In this embodiment, the diameter of the welding core is 2.5-4.0 mm, including but not limited to 2.5 mm, 3.2 mm, 4.0 mm, etc.

[0035] In this embodiment, the coating thickness of the drug coating is 1.5-2.0 mm, including but not limited to 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, etc.

[0036] In some specific embodiments of the present invention, the coating thickness of the coating is: 1.5-1.6 mm for a 2.5 mm welding core, 1.7-1.8 mm for a 3.2 mm welding core, and 1.9-2.0 mm for a 4.0 mm welding core.

[0037] In this embodiment, the eccentricity of the welding rod is less than 3 wires.

[0038] In this embodiment, the electrode for all-position vertical downward welding is an E6013 all-position vertical downward welding electrode.

[0039] In a third aspect, the present invention provides a method for preparing a welding rod for all-position vertical downward welding, comprising the following steps: The raw materials of the flux for all-position vertical downward welding are mixed evenly and then coated on the surface of the welding core, and then dried to obtain the welding rod for all-position vertical downward welding.

[0040] The present invention adopts the all-position vertical downward welding electrode made of the above-mentioned all-position vertical downward welding coating, which has both excellent flat welding performance and excellent vertical downward welding performance. In flat welding and flat corner welding, the weld is beautifully formed and the slag is well removed, especially in flat corner welding, the slag is easy to remove, and the slag shell can be removed by self-cracking or tapping after welding, while the J421 welding rod is often difficult to remove slag in flat corner welding; in flat plate butt welding and corner welding, there is no molten iron or slag dripping, the arc is stable, the operation is free, the slag is easy to remove, and the weld is beautifully formed. The welding rod of the present invention is easy to operate when welding. When performing vertical downward welding or flat corner welding under appropriate current, the welding rod can be dragged against the joint, so new workers can weld beautiful welds with a little training.

[0041] The welding rod of the present invention is not sensitive to moisture absorption, can be used immediately after opening the package, and generally does not need to be dried before use. The welding rod of the present invention can be used for welding using an AC welding machine with a low no-load voltage, and the arc of the welding rod is stable and has excellent re-striking performance.

[0042] In this embodiment, the raw materials of the all-position vertical downward welding coating are mixed evenly by a hydraulic press and then coated on the surface of the welding core. The all-position vertical downward welding electrode of the present invention is used for fillet welding and vertical downward welding, and the eccentricity of the electrode is required to be less than 3 wires. Compared with the spiral machine, the production by the hydraulic press has better advantages.

[0043] Examples 1-3 and Comparative Examples 1-2 Embodiment 1-3 and comparative example 1-2 provide a welding rod for all-position vertical downward welding, comprising a welding core and a coating, wherein the welding core is an H08A carbon steel welding core; the raw materials of the coating include component A and component B; wherein, in parts by weight, the raw material formula of component A is as shown in Table 1; component B is potassium-sodium mixed water glass, and the mass ratio of potassium to sodium is 2:1, the molar ratio (modulus M) is 2.9-3.0, and the Baume degree Be is 42-45 degrees.

[0044] The preparation method is as follows: According to the above formula, the raw materials of component A are mixed evenly as required, and then component B is added and mixed evenly, the mass ratio of component A to component B is 100:23, and then the mixed powder is pressed on the surface of H08A carbon steel welding core by a hydraulic press, and then baked and shaped by a drying machine, and finally inspected and packaged to make welding rods. Among them, in Examples 1-3 and Comparative Examples 1-2, the diameter of the H08A carbon steel welding core is 3.2 mm, and the thickness of the coating is 1.7-1.8 mm.

[0045] Table 1

[0046] Experimental Group The slag removal rate and spatter rate are in accordance with GB / T 25776-2010 "Welding Material Welding Process Performance Evaluation Method", the welding core diameter is 3.2mm, the electrode is DC welding, the flat welding current is 120A, and the vertical downward welding current is 100A.

[0047] Table 2

[0048] Please refer to Table 2. It can be seen from Table 2 that the all-position vertical downward welding electrode of the present invention not only has a very high yield rate (>98%), but also has excellent flat welding performance and excellent vertical downward welding performance, reaching the commercially available level of Japan Kobelco RB-26 and Sweden Isha OK46.00 welding rods, overcoming the shortcomings of existing welding rods and foreign brand products and having excellent welding rod coating performance.

[0049] Compared with Example 1, Comparative Examples 1-2 did not add olivine or added too much olivine, but all resulted in a significant decrease in the yield rate, flat welding performance and vertical downward welding performance, indicating that the addition of olivine is beneficial to improving the yield rate and welding performance of the electrode for vertical downward welding in all positions, but the addition amount should not be too much.

[0050] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A flux for all-position vertical downward welding, characterized in that: The raw materials include component A and component B; wherein, The raw materials of component A include, by weight percentage: 40%-50% rutile, 1%-3% titanium dioxide, 5%-9% marble, 5%-9% olivine, 6%-10% mica, 7%-15% feldspar, 3%-6% sepiolite, 3%-6% talc, 2%-5% wollastonite, 3%-6% starch, 3%-6% microcrystalline fiber, and 7%-10% medium carbon ferromanganese; The component B is a binder.

2. The flux for all-position vertical downward welding according to claim 1, characterized in that: The raw materials of component A include, by weight percentage: 40%-45% rutile, 1%-3% titanium dioxide, 5%-7% marble, 5%-7% olivine, 6%-9% mica, 7%-12% feldspar, 3%-5% sepiolite, 3%-5% talc, 2%-5% wollastonite, 3%-5% starch, 3%-5% microcrystalline fiber, and 7%-8% medium carbon ferromanganese.

3. The flux for all-position vertical downward welding according to claim 1, characterized in that: The binder is water glass.

4. The flux for all-position vertical downward welding according to claim 1, characterized in that: The mass ratio of component A to component B is 100:(23-25).

5. A welding rod for all-position vertical downward welding, characterized in that: The all-position vertical downward welding electrode comprises a welding core and a coating covering the surface of the welding core; wherein, The flux coating is the flux coating for all-position vertical downward welding as described in any one of claims 1-4.

6. The welding rod for all-position vertical downward welding according to claim 5, characterized in that: The welding core is a H08A carbon steel welding core.

7. The welding rod for all-position vertical downward welding according to claim 5, characterized in that: The diameter of the welding core is 2.5-4.0 mm, and the coating thickness of the coating is 1.5-2.0 mm.

8. The all-position vertical downward welding electrode according to claim 5, characterized in that: The welding rod eccentricity is less than 3 wires.

9. A method for preparing a welding rod for all-position vertical downward welding as claimed in claim 5, characterized in that: The following steps are involved: The raw materials of the flux for all-position vertical downward welding according to any one of claims 1 to 4 are mixed evenly and then coated on the surface of the welding core, and then dried to obtain a welding rod for all-position vertical downward welding.

10. The method for preparing the electrode for all-position vertical downward welding according to claim 9, characterized in that: The raw materials of the flux for all-position vertical downward welding are mixed evenly and then coated on the surface of the welding core by hydraulic press coating.

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