Q550qENH uncoated bridge steel welding wire, flux core and deposited metal

Abstract

This invention provides a welding wire, flux core, and deposited metal for welding Q550qENH uncoated bridge steel, belonging to the field of welding materials. The flux core comprises, by weight, the following: titanium dioxide: 3.5-5 parts; ferrosilicon powder: 2-4 parts; silicate: 0.2-0.5 parts; ferroaluminum powder: 0.2-0.4 parts; fluoride: 0.2-0.3 parts; ferromanganese powder: 1-3 parts; nickel powder: 0.6-1.2 parts; copper powder: 0.10-0.40 parts; ferrochrome: 0.2-0.4 parts; quartz sand: 0.3-0.6 parts; zircon sand: 0.2-0.4 parts; iron powder: 0.45-1.8 parts; and electrolytic manganese: 0.8-1.2 parts. This solves the problem that existing welding materials are unsuitable for welding Q550qENH uncoated bridge steel.

Description

Technical Field

[0001] This application relates to the field of welding materials technology, and in particular to a welding wire, flux core and deposited metal for welding Q550qENH uncoated bridge steel. Background Technology

[0002] Unpainted weathering steel is made by adding appropriate amounts of weather-resistant alloying elements such as Cu, Cr, and Ni to ordinary bridge steel. Its combined effect is to form and maintain a dense and stable rust layer on the steel structure surface under specific treatment and suitable environmental conditions, effectively "stopping rust with rust," thus providing long-term resistance to atmospheric corrosion. Unpainted weathering bridges made of unpainted steel not only have lower life-cycle costs but also offer significant environmental benefits by eliminating the need for painting, reducing pollution. Furthermore, they save on the workload and maintenance costs associated with conventional painted steel bridges in harsh natural environments, making them of great practical engineering significance. Countries such as the United States, Japan, and Germany have widely adopted unpainted steel bridges, and my country has also accelerated its construction of unpainted steel bridges in recent years. The rapid development of unpainted weathering steel necessitates the development of matching welding materials.

[0003] With the development trend of high-strength and lightweight steel structure materials, several major steel mills in my country have successfully developed Q550qENH weathering steel. However, welding wire suitable for use with Q550qENH weathering steel plates is still unavailable. Welding with existing wires results in the following defects: significant compositional differences, strength mismatch, insufficient impact toughness at -40℃, or failure to meet corrosion resistance index I requirements. Therefore, there is an urgent need to develop a welding wire suitable for welding Q550qENH uncoated bridge steel. Summary of the Invention

[0004] This application provides a welding wire, flux core, and deposited metal for welding Q550qENH uncoated bridge steel, in order to solve the technical problem that the welding materials in the prior art are not suitable for welding Q550qENH uncoated bridge steel.

[0005] In a first aspect, this application provides a flux core for welding Q550qENH uncoated bridge steel, wherein the raw materials of the flux core, by weight, comprise:

[0006] Titanium dioxide: 3.5 to 5 parts, ferrosilicon powder: 2 to 4 parts, silicate: 0.2 to 0.5 parts, ferroaluminum powder: 0.2 to 0.4 parts, fluoride: 0.2 to 0.3 parts, ferromanganese powder: 1 to 3 parts, nickel powder: 0.6 to 1.2 parts, copper powder: 0.10 to 0.40 parts, ferrochrome: 0.2 to 0.4 parts, quartz sand: 0.3 to 0.6 parts, zircon sand: 0.2 to 0.4 parts, iron powder: 0.45 to 1.8 parts, and electrolytic manganese: 0.8 to 1.2 parts.

[0007] Optionally, the raw materials for the core are, by weight:

[0008] Titanium dioxide: 3.5 parts, ferrosilicon powder: 2 parts, silicate: 0.2 parts, ferroaluminum powder: 0.2 parts, fluoride: 0.2 parts, ferromanganese powder: 1 part, nickel powder: 0.6 parts, copper powder: 0.10 parts, ferrochrome: 0.2 parts, quartz sand: 0.3 parts, zircon sand: 0.2 parts, iron powder: 0.45 parts, electrolytic manganese: 0.8 parts; or,

[0009] Titanium dioxide: 4.2 parts, ferrosilicon powder: 3 parts, silicate: 0.35 parts, ferroaluminum powder: 0.35 parts, fluoride: 0.25 parts, ferromanganese powder: 2 parts, nickel powder: 0.9 parts, copper powder: 0.25 parts, ferrochrome: 0.3 parts, quartz sand: 0.45 parts, zircon sand: 0.3 parts, iron powder: 1.1 parts, electrolytic manganese: 1.0 part; or,

[0010] Titanium dioxide: 5 parts, ferrosilicon powder: 4 parts, silicate: 0.5 parts, aluminum ferropter powder: 0.4 parts, fluoride: 0.3 parts, manganese ferropter powder: 3 parts, nickel powder: 1.2 parts, copper powder: 0.40 parts, chromium ferropter powder: 0.4 parts, quartz sand: 0.6 parts, zircon sand: 0.4 parts, iron powder: 1.8 parts, electrolytic manganese: 1.2 parts.

[0011] Secondly, this application provides a Q550qENH uncoated bridge steel welding wire, the welding wire comprising a steel outer sheath and a flux core as described in the embodiment of the first aspect.

[0012] Optionally, the weight of the flux core is 10% to 20% of the weight of the welding wire.

[0013] Optionally, the filling rate of the flux core is 10% to 20%; the wire diameter of the welding wire is 1.20 mm to 2.40 mm.

[0014] Optionally, the chemical composition of the steel outer skin, by mass fraction, is: C: 0.01% to 0.06%, Mn: 0.10% to 0.40%, Si ≤ 0.04%, S ≤ 0.015%, P ≤ 0.03%, with the balance being iron powder and unavoidable impurities.

[0015] Optionally, the chemical composition of the steel outer skin, by mass fraction, is: C: 0.03%, Mn: 0.25%, Si: 0.03%, S: 0.005%, P: 0.08%, with the balance being iron and unavoidable impurities.

[0016] Thirdly, this application provides a cladding metal for welding Q550qENH uncoated bridge steel, wherein the cladding metal is prepared by welding wire as described in any embodiment of the second aspect during the welding process.

[0017] Optionally, the chemical composition of the deposited metal, in mass fraction, includes:

[0018] C≤0.15%, Mn: 0.75%~2.25%, Si≤0.80%, S≤0.030%, P≤0.030%, Ni: 1.25%~2.60%, Cr≤0.50%, Cu≤0.50%.

[0019] Optionally, the deposited metal satisfies at least one of the following properties: tensile strength R m ≥690MPa, yield strength R el ≥550MPa, elongation A≥14%, impact energy AKV2≥54J at -40℃, diffusible hydrogen content<5mL / 100g, corrosion resistance index I≥6.5.

[0020] The technical solutions provided in this application have the following advantages compared with the prior art:

[0021] This application provides a flux core for welding Q550qENH uncoated bridge steel. Through the organic combination of the above-mentioned flux core raw materials, the tensile strength R of the deposited metal formed after welding is increased. m ≥690MPa, yield strength R el ≥550MPa, elongation A≥14%, impact energy A at -40℃ KV2 With a flux of ≥54J, diffusible hydrogen content <5mL / 100g, and a corrosion resistance index I≥6.5, this effectively improves the overall performance of the weld and solves the problems of insufficient low-temperature toughness and atmospheric corrosion resistance in the weld metal. It exhibits good welding process performance, with a stable arc, minimal spatter, and aesthetically pleasing weld formation. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic flowchart illustrating a method for preparing welding wire for Q550qENH uncoated bridge steel, as provided in an embodiment of this application. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0027] Furthermore, in the description of this application, the terms "comprising," "including," etc., mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0028] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0029] This application provides a flux core for welding Q550qENH uncoated bridge steel. The raw materials of the flux core, by weight, include: titanium dioxide: 3.5 to 5 parts, ferrosilicon powder: 2 to 4 parts, silicate: 0.2 to 0.5 parts, ferroaluminum powder: 0.2 to 0.4 parts, fluoride: 0.2 to 0.3 parts, ferromanganese powder: 1 to 3 parts, nickel powder: 0.6 to 1.2 parts, copper powder: 0.10 to 0.40 parts, ferrochrome: 0.2 to 0.4 parts, quartz sand: 0.3 to 0.6 parts, zircon sand: 0.2 to 0.4 parts, iron powder: 0.45 to 1.8 parts, and electrolytic manganese: 0.8 to 1.2 parts.

[0030] The positive effects of controlling the titanium dioxide content to 3.5 to 5 parts by weight are that it mainly acts as an arc stabilizer and slag-forming agent, ensuring a stable arc and fine weld formation. For example, the titanium dioxide content can be 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 4.0, 4.5, 4.6, 4.8, or 5.0 parts by weight.

[0031] The positive effects of controlling the weight of the ferrosilicon powder to be 2 to 4 parts are as follows: Silicon is an important deoxidizer and also an important alloying agent for weld metal. Adding silicon to the weld can increase the number of acicular ferrite in the weld metal, reduce the oxygen content of the weld metal, and improve the impact toughness of the weld metal. However, if the content is too high, the opposite will occur. Using silicon and manganese combined deoxidation has a better effect. For example, the weight of the ferrosilicon powder can be 2 parts, 2.2 parts, 2.4 parts, 2.6 parts, 3 parts, 2.4 parts, 3.8 parts, 4 parts, etc.

[0032] The positive effects of controlling the silicate content to 0.2 to 0.5 parts by weight are as follows: silicate can play a role in slag formation; if there is too little, the slag-forming effect is not obvious; if there is too much, there will be too many oxides, which will cause a decrease in the low-temperature impact toughness of the weld. For example, the silicate content can be 0.2, 0.3, 0.4, 0.5 parts by weight, etc.

[0033] The positive effects of controlling the weight of the aluminum-iron powder to be 0.2 to 0.4 parts are as follows: the aluminum powder mainly plays a role in preliminary deoxidation. Too little aluminum powder can easily lead to insufficient deoxidation, while too much aluminum powder can cause excessive welding force and increased spatter. For example, the weight of the aluminum-iron powder can be 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, etc.

[0034] The positive effects of controlling the weight of the fluoride to 0.2 to 0.3 parts are as follows: the fluoride can reduce the diffusible hydrogen content in the weld; too little fluoride will not reduce diffusible hydrogen, while too much fluoride will worsen the arc and reduce arc stability. For example, the weight of the fluoride can be 0.2 parts, 0.23 parts, 0.26 parts, 0.28 parts, 0.3 parts, etc.

[0035] The positive effect of controlling the weight of the ferromanganese powder to be 1 to 3 parts is that ferromanganese mainly plays a deoxidizing role. For example, the weight of the ferromanganese powder can be 1 part, 1.3 parts, 1.6 parts, 1.9 parts, 2.1 parts, 2.4 parts, 2.8 parts, 3 parts, etc.

[0036] The positive effects of controlling the weight of this nickel powder to 0.6 to 1.2 parts include: nickel acting as an inoculant, refining grains, reducing segregation, and promoting the formation of acicular ferrite, thereby improving the toughness of ferrite. Nickel also increases dislocation energy, promotes cross-slip of spiral dislocations at low temperatures, increases the energy consumed in crack propagation, and also improves toughness. Ni, along with Cr and Cu, has corrosion-resistant properties. It is mainly derived from metallic nickel. For example, the weight parts of this nickel powder are 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, and 1.2 parts.

[0037] The positive effect of controlling the weight of the copper powder to be 0.10 to 0.40 parts is that adding copper powder to the flux core can improve the atmospheric corrosion resistance of the deposited metal. For example, the weight of the copper powder is 0.10 parts, 0.20 parts, 0.30 parts, 0.40 parts, etc.

[0038] The positive effects of controlling the weight of the ferrochrome to be 0.2 to 0.4 parts are as follows: Cr is one of the main elements forming the rust layer, and as a necessary additive, it improves the atmospheric corrosion resistance. For example, the weight of the ferrochrome is 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, etc.

[0039] The positive effects of controlling the weight of the quartz sand to be 0.3 to 0.6 parts are as follows: Quartz sand can play a role in slag formation and arc stabilization. If there is too little, the arc stabilization effect is not obvious; if there is too much, there will be too many oxides, which will cause the arc to soften and the operation performance to deteriorate. For example, the weight of the quartz sand is 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, etc.

[0040] The positive effects of controlling the zircon sand content to be 0.2 to 0.4 parts by weight: Zircon sand mainly plays a role in slag formation and arc stabilization. For example, the zircon sand content is 0.2 parts, 0.25 parts, 0.30 parts, 0.35 parts, 0.4 parts by weight, etc.

[0041] The positive effect of controlling the weight of the iron powder to be 0.45 parts to 1.8 parts is that the iron powder mainly plays a role in stabilizing the arc. For example, the weight of the iron powder is 0.45 parts, 0.50 parts, 0.70 parts, 0.90 parts, 1.0 parts, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, etc.

[0042] The positive effects of controlling the weight of electrolytic manganese to be 0.8 to 1.2 parts: Electrolytic manganese mainly plays a role in deoxidation. For example, the weight of electrolytic manganese is 0.8 parts, 0.9 parts, 1.0 parts, 1.1 parts, 1.2 parts, etc.

[0043] In some embodiments, the raw materials of the core are, by weight: titanium dioxide: 3.5 parts, ferrosilicon powder: 2 parts, silicate: 0.2 parts, aluminum-iron powder: 0.2 parts, fluoride: 0.2 parts, manganese-iron powder: 1 part, nickel powder: 0.6 parts, copper powder: 0.10 parts, chromium-iron: 0.2 parts, quartz sand: 0.3 parts, zircon sand: 0.2 parts, iron powder: 0.45 parts, electrolytic manganese: 0.8 parts; or, titanium dioxide: 4.2 parts, ferrosilicon powder: 3 parts, silicate: 0.35 parts, aluminum-iron powder: 0.35 parts, fluoride: 0. 25 parts, ferromanganese powder 2 parts, nickel powder: 0.9 parts, copper powder: 0.25 parts, ferrochrome: 0.3 parts, quartz sand: 0.45 parts, zircon sand: 0.3 parts, iron powder: 1.1 parts, electrolytic manganese: 1.0 parts; or, titanium dioxide: 5 parts, ferrosilicon powder: 4 parts, silicate: 0.5 parts, ferroaluminum powder: 0.4 parts, fluoride: 0.3 parts, ferromanganese powder 3 parts, nickel powder: 1.2 parts, copper powder: 0.40 parts, ferrochrome: 0.4 parts, quartz sand: 0.6 parts, zircon sand: 0.4 parts, iron powder: 1.8 parts, electrolytic manganese: 1.2 parts.

[0044] This application provides a Q550qENH uncoated bridge steel welding wire, the welding wire comprising a steel outer sheath and a flux core.

[0045] In some embodiments, the weight of the flux core is 10% to 20% of the weight of the welding wire.

[0046] The positive effects of controlling the weight of the flux core to be 10% to 20% of the weight of the welding wire are: a suitable filler ratio can ensure good slag coverage and good mechanical properties of the weld. For example, the weight of the flux core can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 18%, 19%, 20% of the weight of the welding wire, etc.

[0047] In some embodiments, the filling rate of the flux core is 10% to 20%; the wire diameter of the welding wire is 1.20 mm to 2.40 mm.

[0048] The positive effects of controlling the flux core filling rate to 10%–20% are: a suitable filling ratio can ensure good slag coverage and good mechanical properties of the weld. For example, the filling rate of the flux core can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 18%, 19%, 20%, etc.

[0049] For example, the wire diameter of the welding wire can be 1.20mm, 1.40mm, 1.60mm, 1.80mm, 2.0mm, 2.20mm, 2.40mm, etc.

[0050] In some embodiments, the chemical composition of the steel outer skin, by mass fraction, is: C: 0.01% to 0.06%, Mn: 0.10% to 0.40%, Si ≤ 0.04%, S ≤ 0.015%, P ≤ 0.030%, with the balance being iron powder and unavoidable impurities.

[0051] The positive effects of controlling the C content to 0.01% to 0.06% are that excessive C content can easily lead to cracking. For example, the C content can be 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, etc.

[0052] The positive effect of controlling the Mn content to 0.10% to 0.40% is to ensure the strength of the steel strip. For example, the Mn content can be 0.10%, 0.20%, 0.25%, 0.28%, 0.30%, 0.32%, 0.35%, 0.38%, 0.40%, etc.

[0053] The positive effect of controlling the Si content to ≤0.04% is to ensure the strength of the steel strip. For example, the Si content can be 0.01%, 0.02%, 0.03%, 0.04%, 0.045%, etc.

[0054] The positive effect of controlling the sulfur content to ≤0.015% is the reduction of impurity elements. For example, the sulfur content can be 0.005%, 0.006%, 0.008%, 0.009%, 0.010%, 0.011%, 0.012%, 0.013%, 0.014%, 0.015%, etc.

[0055] The positive effect of controlling the P content to ≤0.030% is the reduction of impurity elements. For example, the P content can be 0.005%, 0.006%, 0.008%, 0.009%, 0.010%, 0.011%, 0.012%, 0.015%, 0.020%, 0.024%, 0.028%, 0.030%, etc.

[0056] In some embodiments, the chemical composition of the steel outer skin, by mass fraction, is: C: 0.03%, Mn: 0.25%, Si: 0.03%, S: 0.005%, P: 0.08%, with the balance being iron and unavoidable impurities.

[0057] Figure 1This is a schematic flowchart illustrating a method for preparing welding wire for Q550qENH uncoated bridge steel, as provided in an embodiment of this application.

[0058] Please see Figure 1 This application provides a method for preparing Q550qENH uncoated bridge steel welding wire, the method comprising:

[0059] S1. Mix the core material to obtain the core mixture;

[0060] S2. Using a wire forming device, the metal outer sheath is used to coat the flux-cored mixture;

[0061] S3. After being coated, it is rolled into wire and then drawn into welding wire.

[0062] This application provides a cladding metal for welding Q550qENH uncoated bridge steel, wherein the cladding metal is obtained by welding wire during the welding process.

[0063] In some embodiments, the chemical composition of the deposited metal, by mass fraction, includes: C ≤ 0.15%, Mn: 0.75%–2.25%, Si ≤ 0.80%, S ≤ 0.030%, P ≤ 0.030%, Ni: 1.25%–2.60%, Cr ≤ 0.50%, Cu ≤ 0.50%.

[0064] The positive effect of controlling the C content to ≤0.15% is reduced crack susceptibility. For example, the C content can be 0.05%, 0.06%, 0.07%, 0.09%, 0.10%, 0.12%, 0.13%, 0.14%, 0.15%, etc.

[0065] The positive effects of controlling the Mn content to be between 0.75% and 2.25% include: appropriate manganese content can improve weld strength, enhance deoxidation, and improve weld impact toughness. For example, the Mn content can be 0.75%, 1.00%, 1.25%, 1.50%, 1.75%, 2.00%, 2.25%, etc.

[0066] The positive effects of controlling the Si content to ≤0.80%: Too high a Si content is detrimental to impact toughness and can cause a decrease in low-temperature impact toughness. For example, the Si content can be 0.30%, 0.35%, 0.40%, 0.45%, 0.50%, 0.55%, 0.60%, 0.65%, 0.70%, 0.75%, 0.80%, etc.

[0067] The positive effects of controlling the sulfur content to ≤0.030% include: controlling impurity elements and preventing hot cracking. For example, the sulfur content can be 0.003%, 0.006%, 0.009%, 0.012%, 0.016%, 0.019%, 0.023%, 0.025%, 0.028%, 0.030%, etc.

[0068] The positive effects of controlling the P content to ≤0.030% include: controlling impurity elements and avoiding cold cracking. For example, the P content can be 0.003%, 0.006%, 0.009%, 0.012%, 0.016%, 0.019%, 0.023%, 0.025%, 0.028%, 0.030%, etc.

[0069] The positive effect of controlling the Ni content to be 1.25% to 2.60% is to improve the low-temperature impact toughness of the weld. For example, the Ni content can be 1.25%, 1.50%, 1.75%, 2.00%, 2.25%, 2.5%, 2.60%, etc.

[0070] The positive effect of controlling the Cr content to ≤0.5% is to improve the corrosion resistance of the weld. For example, the Cr content can be 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, etc.

[0071] The positive effect of controlling the Cu content to ≤0.5% is to improve the corrosion resistance of the weld. For example, the Cu content can be 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, etc.

[0072] In some embodiments, the deposited metal satisfies at least one of the following properties: tensile strength R m ≥690MPa, yield strength R el ≥550MPa, elongation A≥14%, impact energy A at -40℃ KV2 ≥54J, diffusible hydrogen content <5mL / 100g, corrosion resistance index I≥6.5.

[0073] The weld metal produced by the welding wire during the welding process can achieve good mechanical properties and atmospheric corrosion resistance.

[0074] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to industry standards. If there is no corresponding industry standard, then common international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0075] Example 1

[0076] This embodiment provides a Q550qENH uncoated bridge steel welding wire, which includes a steel outer sheath and a flux core. The steel outer sheath is made of steel strip (width × thickness) 14mm × 0.9mm, and its chemical composition by mass fraction is C: 0.03%, Mn: 0.25%, Si: 0.03%, S: 0.005%, P: 0.08%, with the balance being iron and unavoidable impurities. The flux core accounts for 15wt% of the total weight of the welding wire, and the raw materials of the flux core by weight are: titanium dioxide: 3.5 parts, ferrosilicon powder: 2 parts, silicate: 0.2 parts, ferroaluminum powder: 0.2 parts, fluoride: 0.2 parts, ferromanganese powder: 1 part, nickel powder: 0.6 parts, copper powder: 0.10 parts, ferrochrome: 0.2 parts, quartz sand: 0.3 parts, zircon sand: 0.2 parts, iron powder: 0.45 parts, and electrolytic manganese: 0.8 parts.

[0077] Based on the aforementioned steel outer sheath and flux core, this embodiment also provides a method for preparing Q550qENH uncoated bridge steel welding wire, including the following steps:

[0078] The raw materials for the drug core are mixed to obtain the drug core mixture;

[0079] The steel strip is placed in the welding wire forming machine, and the flux core mixture to be used is injected into the groove of the steel strip which is laterally bent into a "U" shape. Then it is rolled into wire and finely drawn to obtain Q550qENH uncoated bridge steel welding wire with a wire diameter of 1.2mm.

[0080] Based on the above welding wire, this embodiment provides a cladding metal obtained during the welding process of Q550qENH uncoated bridge steel welding wire. The welding parameters are: I = 230A~250A, U = 28V~30V, gas flow rate 20L / min, 100% CO2.

[0081] Example 2

[0082] The difference between this embodiment and Embodiment 1 is that the raw materials of the core are as follows (by weight): titanium dioxide: 4.2 parts, ferrosilicon powder: 3 parts, silicate: 0.35 parts, ferroaluminum powder: 0.35 parts, fluoride: 0.25 parts, ferromanganese powder: 2 parts, nickel powder: 0.9 parts, copper powder: 0.25 parts, ferrochrome: 0.3 parts, quartz sand: 0.45 parts, zircon sand: 0.3 parts, iron powder: 1.1 parts, and electrolytic manganese: 1.0 parts.

[0083] Example 3

[0084] The difference between this embodiment and Embodiment 1 is that the raw materials of the core are as follows (by weight): titanium dioxide: 5 parts, ferrosilicon powder: 4 parts, silicate: 0.5 parts, ferroaluminum powder: 0.4 parts, fluoride: 0.3 parts, ferromanganese powder: 3 parts, nickel powder: 1.2 parts, copper powder: 0.40 parts, ferrochrome: 0.4 parts, quartz sand: 0.6 parts, zircon sand: 0.4 parts, iron powder: 1.8 parts, and electrolytic manganese: 1.2 parts.

[0085] The chemical composition and properties of the cladding metals in Examples 1 to 3 were tested, and the test results are shown in Tables 1 and 2.

[0086] Table 1. Chemical composition (wt%) of the cladding metals in Examples 1-3

[0087]

[0088]

[0089] Table 2 shows the performance test results of the cladding metals in Examples 1-3.

[0090]

[0091] As shown in Tables 1 and 2, the welding wire in this embodiment effectively improves the overall performance of the weld during the welding process, solving the problems of insufficient low-temperature toughness and atmospheric corrosion resistance of the weld metal. Welded metal after welding: Tensile strength R m ≥690MPa, yield strength R el ≥550MPa, elongation A≥14%, impact energy A at -40℃ KV2 ≥54J, diffusible hydrogen content <5mL / 100g, corrosion resistance index I≥6.5.

[0092] Furthermore, one or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0093] (1) In the embodiments of the present invention, a high-toughness, uncoated Q550qENH gas-shielded flux-cored welding wire for bridge steel with good welding process performance and physicochemical properties is prepared. In terms of welding process performance, it achieves the goals of stable arc, minimal spatter, and aesthetically pleasing weld formation; in terms of performance, it achieves the goals of good mechanical properties and atmospheric corrosion resistance.

[0094] (2) In this embodiment of the invention, the successful preparation of welding wire suitable for welding Q550qENH uncoated bridge steel saves a lot of construction costs and paves the way for bridge construction in my country. At the same time, the use of uncoated bridge steel eliminates the need for painting, greatly protecting the ecological environment. The social benefits of the research and development of welding materials for bridge steel supporting uncoated weathering steel bridges are particularly significant.

[0095] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A welding wire for welding Q550qENH uncoated bridge steel, characterized in that, The welding wire includes a steel outer sheath and a flux core; The raw materials of the drug core, by weight, include: Titanium dioxide: 3.5-5 parts, ferrosilicon powder: 2-4 parts, silicate: 0.2-0.5 parts, ferroaluminum powder: 0.2-0.4 parts, fluoride: 0.2-0.3 parts, ferromanganese powder: 1-3 parts, nickel powder: 0.6-1.2 parts, copper powder: 0.10-0.40 parts, ferrochrome: 0.2-0.4 parts, quartz sand: 0.3-0.6 parts, zircon sand: 0.2-0.4 parts, iron powder: 0.45-1.8 parts, and electrolytic manganese: 0.8-1.2 parts; The chemical composition of the steel outer skin, expressed as a mass fraction, is as follows: C: 0.01%~0.06%, Mn: 0.10%~0.40%, Si≤0.04%, S≤0.015%, P≤0.03%, balance is iron and unavoidable impurities.

2. The welding wire according to claim 1, characterized in that, The raw materials for the drug core are, by weight, as follows: Titanium dioxide: 3.5 parts, ferrosilicon powder: 2 parts, silicate: 0.2 parts, ferroaluminum powder: 0.2 parts, fluoride: 0.2 parts, ferromanganese powder: 1 part, nickel powder: 0.6 parts, copper powder: 0.10 parts, ferrochrome: 0.2 parts, quartz sand: 0.3 parts, zircon sand: 0.2 parts, iron powder: 0.45 parts, electrolytic manganese: 0.8 parts; or, Titanium dioxide: 4.2 parts, ferrosilicon powder: 3 parts, silicate: 0.35 parts, ferroaluminum powder: 0.35 parts, fluoride: 0.25 parts, ferromanganese powder: 2 parts, nickel powder: 0.9 parts, copper powder: 0.25 parts, ferrochrome: 0.3 parts, quartz sand: 0.45 parts, zircon sand: 0.3 parts, iron powder: 1.1 parts, electrolytic manganese: 1.0 part; or, Titanium dioxide: 5 parts, ferrosilicon powder: 4 parts, silicate: 0.5 parts, aluminum ferropter powder: 0.4 parts, fluoride: 0.3 parts, manganese ferropter powder: 3 parts, nickel powder: 1.2 parts, copper powder: 0.40 parts, chromium ferropter powder: 0.4 parts, quartz sand: 0.6 parts, zircon sand: 0.4 parts, iron powder: 1.8 parts, electrolytic manganese: 1.2 parts.

3. The welding wire according to claim 1, characterized in that, The weight of the flux core is 10% to 20% of the weight of the welding wire.

4. The welding wire according to claim 1, characterized in that, The diameter of the welding wire is 1.20mm to 2.40mm.

5. A weld metal for welding Q550qENH uncoated bridge steel, characterized in that, The deposited metal is obtained from the welding wire described in any one of claims 1 to 4 during the welding process.

6. The weld metal according to claim 5, characterized in that, The chemical composition of the deposited metal, expressed as a mass fraction, includes: C≤0.15%, Mn: 0.75%~2.25%, Si≤0.80%, S≤0.030%, P≤0.030%, Ni: 1.25%~2.60%, Cr≤0.50%, Cu≤0.50%.

7. The weld metal according to claim 5, characterized in that, The deposited metal satisfies at least one of the following properties: tensile strength R m ≥690MPa, yield strength R el ≥550MPa, elongation A≥14%, impact energy at -40℃ A KV2 ≥54J, diffusible hydrogen content <5mL / 100g, corrosion resistance index I≥6.5.

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