Self-shielded flux-cored wire for high-rise building and preparation method thereof

Abstract

The application discloses a self-shielded flux-cored wire for high-rise buildings, which is characterized by comprising a carbon steel outer skin and a flux core, and the flux core comprises the following components in percentage by mass: 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%; zirconium sand 0.5-1.5%; fused magnesite 2.5-4.5%; aluminum-magnesium alloy 10-15%; aluminum powder 10-15%; sintered preformed powder 50-60%; and iron powder in the rest; and the sum of the percentage by mass of the above components is 100%. The self-shielded flux-cored wire has a welding process similar to that of the rutile type gas-shielded flux-cored wire, has a soft and stable electric arc, less spatter, a well-formed weld, a smooth surface, good deslagging, good adaptability to different welding positions, good mechanical properties of the weld metal, and good impact toughness at -30 DEG C.

Description

TECHNICAL FIELD

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

[0002] With the development and utilization of land resources, the scarcity of land resources promotes more high-rise buildings, bridges and outdoor steel structures to rise from the ground. Steel structures have good seismic performance, small self-weight, large rigidity and fast construction speed, and are increasingly widely used. The number of joints of such steel structures is very large, and the number of members is also very large. Various thick plate complex welding processes are applied during construction. In particular, when welding at a high place, the process requires light and stable equipment, low hydrogen type welding materials, wind prevention and the like to ensure the welding quality. The self-shielded flux-cored wire does not need gas protection, is resistant to wind and blowholes, has strong adaptability, can be used for complex position welding, is suitable for multi-layer and multi-pass welding to improve the weld property, has low diffusible hydrogen content, and has unique advantages in welding under harsh construction conditions.

[0003] The special structure of the self-shielded flux-cored wire determines that the spatter generation mechanism thereof is quite different from that of other welding materials, and spatter is more serious during welding. In the welding process, the gas generating agent generates gas inside the wire, which makes the gas pressure inside the arc too large, pushes the metal droplet to the outside, and increases the spatter. According to the research of domestic and foreign scholars, it is found that the spatter rate increases with the increase of fluorides, oxides and carbonates in the core, decreases with the increase of deoxidizers, and the alloying elements have little effect on the spatter.

[0004] The self-shielded flux-cored wire uses the gas generated by the gas generating agent and the steam formed by metal evaporation to form protection for the weld, and in harsh environments, it is easy to be insufficiently protected, resulting in blowholes, which is also a common defect of the self-shielded flux-cored wire.

[0005] The self-shielded flux-cored wire in the prior art that is resistant to blowholes and wind mainly improves the gas protection capacity by increasing fluorides, carbonates and Al, Mg and the like in the powder, improves the deoxidation and denitrification effect, and is suitable for outdoor and harsh environment use. Due to the addition of a large amount of Al element, the self-shielded flux-cored wire is easy to cause unstable impact toughness of the weld, and is prone to low values.

[0006] The high-toughness self-shielded flux-cored wire in the prior art controls the inclusion size by adding rare earth elements to improve the low-temperature impact value. For example, a self-shielded flux-cored wire for pipelines that uses fluorides and carbonates to generate gas, Al and Mg to deoxidize, and rare earth elements to increase toughness, has an impact of 200J or more at-40℃, and improves the control of the toughness of the welded joint of the pipeline steel.

[0007] Or by a plurality of fluoride combination, add rare earth, nickel's self-shielded flux-cored wire, through low fluorinated lithium, potassium fluoride and so on optimization arc, reduce spatter, -40 DEG C impact reaches 135J, obtain a kind of self-shielded flux-cored wire with good comprehensive performance.

[0008] At present, self-shielded flux-cored wire still has the shortage in spatter, deslagging, easy operation etc., welding process performance is comparable with rutile type flux-cored wire, and the mechanical property is stable, and it is very rare to weld complex position large size self-shielded flux-cored wire, therefore it is necessary to invent a reliable large diameter self-shielded flux-cored wire with all aspects of performance equivalent to rutile type, provide for the future broad outdoor engineering field.

[0009] There is no self-shielded flux-cored wire without fluorine in the disclosed research which is comparable with rutile type gas shielded flux-cored wire in welding process.The present application obtains a self-shielded flux-cored wire suitable for complex position by innovative research of a slag system and proper preparation method, which has the welding operation performance comparable with rutile type and excellent mechanical property and good impact toughness at-30 DEG C. SUMMARY

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

[0011] Compared with the prior art, the present application has welding process comparable with rutile type gas shielded flux-cored wire, soft and stable arc, less spatter, good weld forming, smooth surface, good deslagging, especially good adaptability to different welding positions, good mechanical property of weld metal and good impact toughness at-30 DEG C.

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

[0013] Electrolytic manganese 0.5-1.5%;

[0014] Ferro-titanium 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] Zirconium sand 0.5-1.5%;

[0019] Electro-melting magnesite 2.5-4.5%;

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

[0021] aluminum powder 10-15%;

[0022] sintered pre-made powder 50-60%;

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

[0024] In a preferred embodiment of the present application, the proportion of the core in the total mass of the welding wire, i.e. the filling rate, is 22-25%.

[0025] In a preferred embodiment of the present application, the carbon steel sheath is of SPCC material.

[0026] In a preferred embodiment of the present application, the sintered pre-made powder is sintered from 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 application, the sintering of the pre-made powder is carried out by mixing the components except for the potassium water glass, adding the potassium water glass in portions and mixing again, sintering at 500±10°C for 2 hours, and cooling in the furnace. The sintered pre-made powder is obtained by mechanically crushing and sieving the sintered pre-made powder between 60-200 mesh.

[0034] A method for preparing a self-protecting flux-cored wire for high-rise buildings, comprising the following steps:

[0035] First, a pretreatment step,

[0036] high-temperature baking of the barium carbonate, strontium carbonate, zircon sand and fused magnesite;

[0037] Second, a mixing step,

[0038] mixing the product of the previous step with the other core components in the appropriate proportions and filling into the carbon steel sheath.

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

[0040] In a preferred embodiment of the present application, the filling into the carbon steel outer skin is to roll the steel strip into a U shape, fill the mixed powder in a proportion of 22-25% by using a powder filling machine, and then roll the U-shaped groove into a "O" shape by closing the mouth, and then draw the diameter of the welding wire to 1.6-2.4mm by wire drawing, to obtain the final product welding wire.

[0041] The present application has the following beneficial effects:

[0042] The present application has a welding process comparable to the rutile type gas shielded flux cored wire, the arc is soft and stable, the spatter is less, the weld forming is good, the surface is smooth, the deslagging is good, especially the adaptability to different welding positions is good, the mechanical properties of the weld metal are good, and the impact toughness at-30℃ is good. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The welding test effect schematic diagram for example 2.

[0044] Figure 2 The weld deslagging effect schematic diagram for example 2.

[0045] Figure 3 The vertical welding deslagging effect schematic diagram for example 2.

[0046] Figure 4 The overhead welding deslagging effect schematic diagram for example 2. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical scheme and advantages of the present application more clear and obvious, the present application is further described in detail below by means of drawings and examples. However, it should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the scope of the present application. 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 application.

[0048] Table 1 is the composition and mechanical properties of the steel strip in each example

[0049]

[0050] The present application tests 5 groups of flux cored wires, as follows:

[0051] Table 2 is the composition of the flux core in each example

[0052] Materials Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Sintered preformed powder 51 52.5 55 45 65 Aluminium powder 10.5 12.5 13.5 15 10 Aluminium magnesium alloy 12.5 14 13 15 10 Zircon sand 1 1 1 1.5 1 Electrolytic magnesium 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 Titanium iron 1 1 1 1 0.75 Electrolytic manganese 1 1 1 1 0.75 Iron powder 12.75 6.4 2.5 8 3.25 Fill rate % 22.5-23.0％ 23.5-24.0％ 24.0-24.5％ 23.5-24％ 23.5-24％ Specification mm 1.6 2.0 2.4 2.0 2.0

[0053] Among them, the composition ratio in the sintered preformed powder is as follows:

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

[0055] The welding test of the comparative example 1 was not uniform in slag coverage, and part of the weld was not protected by slag, resulting in poor weld formation, so the composition and performance of the weld metal were not detected.

[0056] The welding test of the comparative example 2 was high in porosity sensitivity, prone to internal porosity and surface porosity, and the arc stability was reduced, so the composition and performance of the weld metal were not detected.

[0057] Table 3 is the composition of the deposited metal of each example

[0058] Materials 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 is the performance of the weld metal of each example

[0060]

[0061] In actual welding operation, the self-protection flux-cored wire of the present application has a soft and stable arc, droplet spray transition, small 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 and has good welding process and easy operation, as shown in the drawings.

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

[0063] The above shows and describes the basic principles and main features of the invention and the advantages of the invention.

[0064] Those skilled in the art should understand that the present application is not limited to the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A self-shielded flux-cored wire for high-rise buildings, characterized by comprising: It comprises a carbon steel outer skin and a core, the core comprising the following components by mass percentage: Electrolytic manganese 0.5-1.5%; Titanium iron 0.5-1.5%; Silicon-zirconium alloy 0.5-2.0%; Barium carbonate 0.5-1.5%; Lithium carbonate 4.0-6.5%; Zirconium sand 0.5-1.5%; Fused magnesite 2.5-4.5%; Aluminum-magnesium alloy 10-15%; Aluminum powder 10-15%; Sintered preform powder 50-60%; Iron powder the balance, the sum of the mass percentages of the above components being 100%; The sintered preform powder is sintered from 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%.

2. A self-shielded flux-cored wire for high-rise buildings according to claim 1, wherein The proportion of the core in the total mass of the welding wire, i.e. the filling rate, is 22-25%.

3. A self-shielded flux-cored wire for high-rise buildings according to claim 1, wherein The carbon steel outer skin is of SPCC material.

4. A self-shielded flux-cored wire for high-rise buildings according to claim 1, wherein The sintered preform is prepared by mixing the components except for the potassium water glass, adding the potassium water glass in portions and mixing again, sintering at 500±10℃ for 2 hours, cooling in the furnace, mechanically crushing the sintered preform powder, and sieving to obtain the sintered preform powder of 60-200 mesh.

5. A method of manufacturing a self-shielded flux-cored wire for high-rise buildings according to any one of claims 1 to 4, characterized in that, It comprises the following steps: First, a pretreatment step, High-temperature baking of the barium carbonate, strontium carbonate, zirconium sand, and fused magnesite; Second, a mixing step, Mixing the product of the previous step with the other core components in the appropriate proportions and filling into the carbon steel outer skin.

6. The method of producing a self-shielded flux-cored wire for high-rise buildings according to claim 5, characterized by, The high-temperature baking is baking at 500℃ for 2 hours.

7. The method of manufacturing a self-shielded flux-cored wire for high-rise buildings according to claim 5, wherein the flux-cored wire is manufactured by the steps of: mixing the flux powder with the flux solvent to prepare the flux slurry; and mixing the flux slurry with the flux solvent to prepare the flux solution. The filling into the carbon steel outer skin is rolling the steel strip into a U shape, filling the mixed powder into the U-shaped groove according to a proportion of 22-25% using a powder filling machine, rolling the U-shaped groove to close the mouth into an "O" shape, and drawing the diameter of the welding wire to 1.6-2.4mm by wire drawing to obtain the final product welding wire.

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