Self-protection flux-cored wire for high-rise building and preparation method of self-protection flux-cored wire

Abstract

The invention discloses a self-protection flux-cored wire for high-rise buildings, which is characterized in that the self-protection flux-cored wire comprises a carbon steel sheath and a flux core, and the flux core comprises the following components by mass percent: 0.5-1.5% of electrolytic manganese; 0.5 to 1.5 percent of ferrotitanium; 0.5 to 2.0 percent of silicon zirconium alloy; 0.5 to 1.5 percent of barium carbonate; 4.0 to 6.5 percent of lithium carbonate; 0.5 to 1.5 percent of zircon sand; 2.5%-4.5% of fused magnesite; 10-15% of an aluminum-magnesium alloy; 10-15% of aluminum powder; 50-60% of sintering prefabricated powder; the sum of the mass percentages of the components is 100%. The welding process comparable with a rutile type gas shielded flux-cored wire is soft and stable in electric arc, little in splashing, good in weld forming, smooth in surface, good in deslagging, especially good in adaptability to different welding positions, good in weld metal mechanical property and good in impact toughness at the temperature of-30 DEG C.

Description

Technical Field

[0001] The invention relates to the field of welding manufacturing, and in particular to a self-shielded flux-cored welding wire for high-rise buildings and a preparation method thereof. Background Art

[0002] With the development and utilization of land resources, the scarcity of land resources has driven more high-rise buildings, bridges and outdoor steel structures to rise from the ground. Steel structures have good seismic performance, light weight, high rigidity, fast construction speed, and are increasingly widely used. This type of steel structure has a large number of joints and rods. During construction, complex welding processes of various thick plates will be applied. Especially when welding at high altitudes, the process requires light equipment and high stability. Low-hydrogen welding materials are selected, and attention is paid to wind protection to ensure welding quality. Self-shielded flux-cored welding wire does not require gas protection, is wind-resistant and pore-resistant, has strong adaptability, can perform complex position welding, is suitable for multi-layer and multi-pass welding to improve weld metal performance, has a low content of diffusible hydrogen, and has unique advantages in welding under harsh construction conditions.

[0003] The special structure of self-shielded flux-cored welding wire determines that its spatter generation mechanism is quite different from other welding materials, and the spatter is more serious during welding. During the welding process, the gasifier generates gas inside the welding wire, which makes the gas pressure inside the arc too high, pushing the metal droplets to the outside and increasing the spatter. According to the research of domestic and foreign scholars, the spatter rate increases with the increase of fluoride, oxide and carbonate in the flux core, and decreases with the increase of deoxidizer. Alloy elements have almost no effect on spatter.

[0004] Self-shielded flux core uses the gas generated by the gasifier and the steam formed by metal evaporation to protect the weld. In harsh environmental conditions, insufficient protection may lead to porosity, which is also a common defect of self-shielded flux cored welding wire.

[0005] The existing self-shielded flux-cored welding wires that are resistant to porosity and wind are mainly used to increase the gasification protection ability by adding fluoride, carbonate, Al, Mg, etc. in the powder, improve the deoxidation and denitrification effect, and adapt to outdoor and harsh environments. The self-shielded flux-cored welding wires are prone to unstable weld impact toughness and are prone to low values ​​due to the addition of a large amount of Al elements.

[0006] The existing high-toughness self-shielded flux-cored welding wire controls the size of inclusions by adding rare earth elements to improve the low-temperature impact value. For example, a pipeline self-shielded flux-cored welding wire with fluoride and carbonate gasification, aluminum and magnesium deoxidation, and rare earth elements to increase toughness has an impact of more than 200J at -40℃, which improves the control of the toughness of pipeline steel welding joints.

[0007] Or through a combination of one or more fluorides, adding rare earth and nickel to a self-shielded flux-cored welding wire, optimizing the arc through low lithium fluoride, potassium fluoride, etc., reducing spatter, and achieving an impact of 135J at -40°C, to obtain a self-shielded flux-cored welding wire with better comprehensive performance.

[0008] At present, self-shielded flux-cored welding wire still has shortcomings in spatter, slag removal, and easy operation. The welding process performance is comparable to that of rutile flux-cored welding wire. Large-sized self-shielded flux-cored welding wire with stable mechanical properties and capable of welding complex positions is very rare. Therefore, it is very necessary to invent a reliable large-diameter self-shielded flux-cored welding wire with performance equivalent to rutile in all aspects, and provide it to the vast outdoor engineering field in the future.

[0009] There is no welding process comparable to rutile gas-shielded flux-cored welding wire and self-shielded flux-cored welding wire without fluoride in the research that has been made public. The present invention innovatively studies a slag system and adopts an appropriate preparation method to obtain a self-shielded flux-cored welding wire suitable for complex positions. While having the welding operability equivalent to rutile, it also has excellent mechanical properties and good -30℃ impact toughness. Summary of the invention

[0010] In order to overcome the above-mentioned defects of the prior art, an object of the present invention is to provide a self-shielded flux-cored welding wire for high-rise buildings and a preparation method thereof.

[0011] Compared with the prior art, the present invention has a welding process comparable to that of rutile gas-shielded flux-cored welding wire, with a soft and stable arc, less spatter, good weld formation and smooth surface, good slag removal, especially good adaptability to different welding positions, good mechanical properties of the weld metal, and good impact toughness at -30°C.

[0012] A self-shielded flux-cored welding wire for high-rise buildings, comprising a carbon steel outer sheath and a flux core, wherein the flux core comprises the following components calculated by mass percentage:

[0013] Electrolytic manganese 0.5-1.5%;

[0014] Ferrotitanium 0.5-1.5%;

[0015] Silicon-zirconium alloy 0.5-2.0%;

[0016] Barium carbonate 0.5-1.5%;

[0017] Lithium carbonate 4.0-6.5%;

[0018] Zircon sand 0.5-1.5%;

[0019] Fused magnesia 2.5-4.5%;

[0020] Aluminum-magnesium alloy 10-15%;

[0021] Aluminum powder 10-15%;

[0022] Sintering preformed powder 50-60%;

[0023] Iron powder balance, the sum of the mass percentages of the above components is 100%.

[0024] In a preferred embodiment of the present invention, the proportion of the flux core to the total mass of the welding wire, that is, the filling rate, is 22-25%.

[0025] In a preferred embodiment of the present invention, the carbon steel outer skin is made of SPCC material.

[0026] In a preferred embodiment of the present invention, the sintered preformed powder is sintered and preformed by the following components:

[0027] Strontium carbonate 13-17%;

[0028] Ferrous oxide 40-50%;

[0029] Hematite 15-20%;

[0030] Microcrystalline cellulose 5-8%;

[0031] Quartz 3-5%;

[0032] Potassium water glass 12-18%.

[0033] In a preferred embodiment of the present invention, the sintering prefabrication is to mix all components except potassium water glass, add potassium water glass in batches, mix again, sinter and keep warm at 500±10℃ for 2 hours, and cool with the furnace. The sintering prefabricated powder is mechanically crushed and sieved to obtain the sintering prefabricated powder between 60-200 mesh.

[0034] A method for preparing a self-shielded flux-cored welding wire for high-rise buildings comprises the following steps:

[0035] First, the preprocessing step,

[0036] The barium carbonate, strontium carbonate, zircon sand and fused magnesia sand are baked at high temperature;

[0037] Second, the mixing step,

[0038] The product of the previous step is mixed with other core components in proportion and then filled into the carbon steel sheath.

[0039] In a preferred embodiment of the present invention, the high temperature baking is baking at 500° C. for 2 hours.

[0040] In a preferred embodiment of the present invention, the filling into the carbon steel outer skin is to roll the steel strip into a U-shape, use a powder feeder to fill the mixed powder at a ratio of 22-25%, and then roll the U-shaped groove into an "O" shape, and then draw the wire to a diameter of 1.6-2.4mm through wire drawing to obtain the final finished welding wire.

[0041] The beneficial effects of the present invention are:

[0042] The invention has a welding process comparable to that of rutile gas shielded flux-cored welding wire, with soft and stable arc, less spatter, good weld formation and smooth surface, good slag removal, especially good adaptability to different welding positions, good weld metal mechanical properties, and good -30°C impact toughness. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the weldability test effect of Example 2.

[0044] Figure 2 This is a schematic diagram of the effect of weld slag removal in Example 2.

[0045] Figure 3 This is a schematic diagram of the effect of vertical welding slag removal in Example 2.

[0046] Figure 4 This is a schematic diagram of the slag removal effect after overhead welding in Example 2. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below through the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of the present invention. In addition, in the following structure, the description of the known structure and technology is omitted to avoid unnecessary confusion of the concept of the present invention.

[0048] Table 1 shows the composition and mechanical properties of the steel strips in each embodiment.

[0049]

[0050] The present invention tested 5 groups of flux-cored welding wires, which are as follows:

[0051] Table 2 shows the core components in each example.

[0052] Material Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Sintering preform powder 51 52.5 55 45 65 Aluminum powder 10.5 12.5 13.5 15 10 Aluminum-magnesium alloy 12.5 14 13 15 10 Zircon sand 1 1 1 1.5 1 Fused magnesia 3 3 4 4 3 Lithium carbonate 5 5.6 6 6 4.5 Barium carbonate 1 1 1 1.5 0.75 Silicon Zirconium Alloy 1.25 2 2 2 1 Ferrotitanium 1 1 1 1 0.75 Electrolytic Manganese 1 1 1 1 0.75 Iron Fan 12.75 6.4 2.5 8 3.25 Filling rate % 22.5-23.0％ 23.5-24.0％ 24.0-24.5％ 23.5-24％ 23.5-24％ Specifications (mm) 1.6 2.0 2.4 2.0 2.0

[0053] Among them, the proportions of each component in the sintered preformed powder are as follows:

[0054] Strontium carbonate 12%, ferrous oxide 45%, hematite 17%, microcrystalline cellulose 7%, quartz 4%, common potassium water glass 15%.

[0055] Among them, in the welding test of comparative example 1, the slag coverage was uneven, and part of the weld was not protected by slag, resulting in poor weld formation. Therefore, the weld metal composition and performance testing were not performed.

[0056] Among them, in the welding test of Comparative Example 2, the porosity sensitivity is relatively high, internal pores and surface pores are prone to occur, and the arc stability is reduced, so the weld metal composition and performance testing are not performed.

[0057] Table 3 shows the composition of the deposited metal in each example.

[0058] Material Example 1 Example 2 Example 3 C 0.244 0.240 0.227 Mn 0.45 0.42 0.43 Si 0.17 0.15 0.14 S 0.009 0.008 0.009 P 0.010 0.010 0.011 Al 0.57 0.62 0.65

[0059] Table 4 shows the weld metal properties of each embodiment.

[0060]

[0061] In actual welding operation, the self-shielded flux-cored welding wire of the present invention has a gentle and stable arc, a molten droplet jet transition, fine spatter, moderate slag viscosity, fast slag solidification, good slag removal, and a bright and beautiful weld surface after slag removal. It can be welded in all positions with good welding processability and is easy to operate. See the attached drawings for details.

[0062] According to the above experimental data, the deposited metal has high low-temperature (-30°C) impact toughness, and an appropriate amount of transition alloy elements can ensure that the weld metal has excellent strength and high low-temperature impact toughness.

[0063] The basic principles and main features of the invention and the advantages of the invention are shown and described above.

[0064] Those skilled in the art should understand that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A self-shielded flux-cored welding wire for high-rise buildings, characterized in that: It includes a carbon steel outer skin and a core. The core is composed of the following components by mass percentage: Electrolytic manganese 0.5-1.5%; Ferrotitanium 0.5-1.5%; Silicon-zirconium alloy 0.5-2.0%; Barium carbonate 0.5-1.5%; Lithium carbonate 4.0-6.5%; Zircon sand 0.5-1.5%; Fused magnesia 2.5-4.5%; Aluminum-magnesium alloy 10-15%; Aluminum powder 10-15%; Sintering preformed powder 50-60%; Iron powder balance, the sum of the mass percentages of the above components is 100%.

2. A self-shielded flux-cored welding wire for high-rise buildings as claimed in claim 1, characterized in that: The proportion of the flux core to the total mass of the welding wire, that is, the filling rate, is 22-25%.

3. A self-shielded flux-cored welding wire for high-rise buildings as claimed in claim 1, characterized in that: The carbon steel outer skin is made of SPCC material.

4. A self-shielded flux-cored welding wire for high-rise buildings as claimed in claim 1, characterized in that: The sintered preformed powder is sintered and preformed by the following components: Strontium carbonate 13-17%; Ferrous oxide 40-50%; Hematite 15-20%; Microcrystalline cellulose 5-8%; Quartz 3-5%; Potassium water glass 12-18%.

5. A self-shielded flux-cored welding wire for high-rise buildings as claimed in claim 4, characterized in that: The sintering prefabrication is to mix all components except potassium water glass, add potassium water glass in batches, mix again, sinter and keep warm at 500±10°C for 2 hours, and cool with the furnace. The sintering prefabrication powder is mechanically crushed and sieved to obtain the sintering prefabrication powder between 60-200 mesh.

6. A method for preparing a self-shielded flux-cored welding wire for high-rise buildings as claimed in any one of claims 1 to 5, characterized in that: The steps include: First, the preprocessing step, The barium carbonate, strontium carbonate, zircon sand and fused magnesia sand are baked at high temperature; Second, the mixing step, The product of the previous step is mixed with other core components in proportion and then filled into the carbon steel sheath.

7. The method for preparing a self-shielded flux-cored welding wire for high-rise buildings according to claim 6, characterized in that: The high temperature baking is baking at 500° C. for 2 hours.

8. The method for preparing a self-shielded flux-cored welding wire for high-rise buildings according to claim 6, characterized in that: The filling into the carbon steel outer skin is to roll the steel strip into a U-shape, use a powder adding machine to fill the mixed powder at a ratio of 22-25%, then roll the U-shaped groove into an "O" shape, and draw the welding wire to a diameter of 1.6-2.4mm through wire drawing to obtain the final finished welding wire.

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