A submerged arc welding wire suitable for high heat input welding of 50~150kJ / cm and its application

Abstract

This invention provides a submerged arc welding wire suitable for high heat input welding of 50–150 kJ / cm and its application, belonging to the field of welding materials technology. The submerged arc welding wire provided by this invention comprises the following chemical composition: C: 0.07–0.12%, Si≤0.09%, Mn: 1.70–1.95%, P≤0.012%, S≤0.005%, Ni: 0.55–1.00%, Mo: 0.40–0.58%, Ti: 0.11–0.24%, Nb≤0.05%, V: 0.03–0.04%, Ca≤0.0015%, B: 0.0005–0.0045%, Ce≤0.030%, and the balance Fe. The submerged arc welding wire provided by this invention meets the requirements for the mechanical properties of the deposited metal at a heat input of 50–150 kJ / cm, and is applicable to the production of large welded structural components and high-efficiency welding manufacturing.

Description

Technical Field

[0001] This invention relates to the field of welding materials technology, and in particular to a submerged arc welding wire suitable for welding with a high heat input of 50-150 kJ / cm and its application. Background Technology

[0002] In recent years, with the rapid development of high heat input welding technology in the welding field, and in order to promote the steel industry towards efficient and intelligent manufacturing, improve the welding efficiency of large-span, thick-gauge bridge structural components and ship berths, shorten manufacturing time, and reduce costs, there is an urgent need to develop high-heat-input welding technology and matching welding materials to achieve efficient, green, and intelligent manufacturing. High heat input welding requires high-performance welding materials, but currently, steel structure manufacturers use ordinary welding materials with high heat input to improve production efficiency. This leads to a sharp decrease in the toughness of the weld metal, making it difficult to ensure the match between the mechanical properties of the weld metal and the high welding heat input. This is because as the welding heat input increases, the cooling rate of the weld zone decreases, and the weld metal structure tends to coarsen. Therefore, developing efficient and high-performance welding materials offers advantages such as high production efficiency, energy saving, aesthetically pleasing results, low pollution, and ease of automation, making it a promising welding material.

[0003] Chinese invention patent application CN201410728048.4 discloses "a high heat input submerged arc welding wire," which adds 0.01-0.05% Ti to form TiN to pin austenite grain boundaries and prevent austenite grain growth. On the other hand, it promotes high melting points by adding alloying elements such as Si, Mn, Ti, Al, Ce, and Mg. The welding wire is matched with alkaline sintered flux GM55, and the heat input is in the range of 60kJ / cm-160kJ / cm, resulting in excellent weld performance at low temperatures. However, during high heat input welding (greater than 50kJ / cm), Ti burn-off is relatively severe, and the amount of 0.01-0.05% titanium transitioning into the weld metal is relatively small. Furthermore, in the embodiments, butt joint tests were conducted using high heat input welding. The high heat input welding resulted in a large weld metal fusion ratio, further diluting the effective components of the weld metal. Therefore, in the embodiments, the -40°C low-temperature impact value at the weld center was relatively low.

[0004] Chinese invention patent application CN200910046732.3 discloses a "high-toughness submerged arc welding wire" with moderate strength, high impact toughness, and high heat input resistance, particularly suitable for welding Q390A-Q390E and Q420A-Q420E grade steels. By optimizing carbon content, controlling the maximum upper limit of silicon content, and combining it with a Mn-Ni system, it effectively improves low-temperature toughness, high heat input resistance, and provides appropriate yield strength and tensile strength. However, in high-heat-input welding processes, the grain growth trend is quite pronounced, and simply adding Ni to refine the ferrite phase grains to improve toughness is insufficient; adding too much Ni would increase the cost of welding wire smelting. Similarly, this invention patent is applicable to welding heat inputs of 30-40 kJ / cm, which is still somewhat different from high-heat-input welding.

[0005] Chinese invention patent application CN201410666124.3 discloses a submerged arc welding wire with excellent low-temperature toughness for offshore platform construction. The chemical composition of the welding wire, by weight (%), contains C 0.01-0.15%; Si 0.1-0.9%; Mn 0.5-2.0%; Ni 0.1-1.5%; Mo 0.1-0.6%; Ti 0.01-0.25%; Al ≤ 0.01%, and Ce ≤ 0.4%. However, in the submerged arc welding process, Si is generally transitioned through the flux, and excessive content will reduce the low-temperature toughness of the weld. The upper limit of Si content in the welding wire of this invention is relatively high. Similarly, in high heat input welding, the weld metal cools slowly, and the formation of proeutectoid ferrite at grain boundaries will have a significant impact on the toughness of the weld metal. Therefore, adding an appropriate amount of Si in high heat input welding is beneficial to suppressing the formation of proeutectoid ferrite and side strip ferrite.

[0006] Chinese invention patent application CN01135349.X discloses a complete technology for "high heat input submerged arc welding joint, its manufacturing method, and the welding wire and flux used". The welding wire for high heat input submerged arc welding is composed of C: 0.03-0.10%, N: ≤0.0035%, Si: ≤0.4%, Mn: 1.0-2.5%, and Ti above 0.03%, satisfying a Ti / N ratio of 15-50. The welding wire composition also contains one or more of Mo, Nb, B, and Ni, and the weld metal composition of the joint must satisfy 0.6 ≤ B / N ≤ 1.2, and the amount of grain boundary ferrite in the weld metal must be controlled to be below 10.0% of its area. This invention patent technology is complex, has high requirements, and is difficult to implement. Furthermore, although the submerged arc welding wire of this invention can be used for welding under a high heat input of 150 kJ / cm, the examples only provide the low-temperature impact toughness at 0℃ and -20℃, and fail to provide the low-temperature impact toughness value required for Grade E steel at -40℃.

[0007] Chinese invention patent application CN92105621.4 discloses a "low-carbon micro-alloyed submerged arc welding wire," mainly suitable for the pipe manufacturing and construction of oil and gas pipelines. It adds 1.2–1.6% Mn and 0.2–0.4% Mo to improve weld strength through solid solution strengthening; and adds 0.02–0.08% Ti and 0.001–0.008% B to improve weld toughness through a composite effect, where Ti can also combine with free N. While this invention indicates its applicability to high heat input and high-speed welding, it does not specify the welding heat input. If this welding wire is applied under the high heat input welding conditions (50–125 kJ / cm) applicable to this invention, the trace amounts of Ti and B will be significantly burned off. Furthermore, the welding wire does not contain Ni, which has a relatively stable transition coefficient. Under high heat input welding conditions, the mechanical properties of the weld, especially the low-temperature impact toughness of the joint, are difficult to guarantee.

[0008] To improve the welding efficiency of large steel structures such as bridges, selecting superior submerged arc welding wire is a crucial way to further enhance welding efficiency, reduce costs, improve the mechanical properties of welded joints, and replace imported products. Therefore, developing a submerged arc welding wire suitable for Q420–Q460qE grade welding heat inputs of 50–150 kJ / cm² while meeting the mechanical property requirements of relevant standards and specifications has become a pressing problem in this field. Summary of the Invention

[0009] The purpose of this invention is to provide a submerged arc welding wire suitable for welding with a high heat input of 50-150 kJ / cm and its application. The submerged arc welding wire provided by this invention achieves various specifications for the mechanical properties of the deposited metal within the heat input range of 50-150 kJ / cm, that is, it obtains good strength and plasticity while also having excellent low-temperature impact toughness. It can be applied to the production and efficient welding manufacturing of large welded structural components in industries such as bridges, ships and buildings.

[0010] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0011] This invention provides a submerged arc welding wire suitable for high heat input welding of 50-150 kJ / cm, comprising the following chemical composition by mass percentage: C: 0.07-0.12%, Si≤0.09%, Mn: 1.70-1.95%, P≤0.012%, S≤0.005%, Ni: 0.55-1.00%, Mo: 0.40-0.58%, Ti: 0.11-0.24%, Nb≤0.05%, V: 0.03-0.04%, Ca≤0.0015%, B: 0.0005-0.0045%, Ce≤0.030%, and the balance Fe;

[0012] The chemical composition ratio of the submerged arc welding wire conforms to 620≤θ≤715;

[0013] θ = 9.8 × (36.69 + 160.6W) C +5.28W Mn +2.618W Ni +6.966W Mo +2.24W Ti ).

[0014] Preferably, the submerged arc welding wire comprises the following chemical composition by mass percentage: C: 0.08-0.11%, Si≤0.09%, Mn: 1.75-1.90%, P≤0.012%, S≤0.005%, Ni: 0.60-0.90%, Mo: 0.40-0.58%, Ti: 0.11-0.24%, Nb≤0.05%, V: 0.03-0.04%, Ca≤0.0015%, B: 0.0005-0.0045%, Ce≤0.030%, and the balance Fe.

[0015] Preferably, the submerged arc welding wire comprises the following chemical composition by mass percentage: C: 0.08-0.11%, Si ≤ 0.09%, Mn: 1.80-1.85%, P ≤ 0.012%, S ≤ 0.005%, Ni: 0.70-0.80%, Mo: 0.45-0.55%, Ti: 0.15-0.20%, Nb ≤ 0.05%, V: 0.03-0.04%, Ca ≤ 0.0015%, B: 0.0015-0.0035%, Ce ≤ 0.030%, and the balance Fe.

[0016] Preferably, the chemical composition ratio of the submerged arc welding wire conforms to 630≤θ≤705.

[0017] Preferably, the chemical composition ratio of the submerged arc welding wire conforms to 640≤θ≤700.

[0018] Preferably, the submerged arc welding wire contains at least one of Nb, Ca, and Ce.

[0019] Preferably, the submerged arc welding wire further comprises Pb, Sn, As, Sb and Bi, and Pb+Sn+As+Sb+Bi≤0.010%.

[0020] Preferably, the submerged arc welding wire further includes a copper plating layer disposed on its surface, the thickness of which is 0.19–0.23 μm.

[0021] This invention provides the application of the submerged arc welding wire, which is suitable for high heat input welding of 50-150 kJ / cm, in submerged arc welding and flux copper backing method.

[0022] Preferably, the submerged arc welding wire is used in the production and efficient welding manufacturing of large welded structural components in the bridge, shipbuilding and construction industries.

[0023] This invention provides a submerged arc welding wire suitable for high heat input welding of 50-150 kJ / cm, comprising the following chemical composition by mass percentage: C: 0.07-0.12%, Si≤0.09%, Mn: 1.70-1.95%, P≤0.012%, S≤0.005%, Ni: 0.55-1.00%, Mo: 0.40-0.58%, Ti: 0.11-0.24%, Nb≤0.05%, V: 0.03-0.04%, Ca≤0.0015%, B: 0.0005-0.0045%, Ce≤0.030%, and the balance Fe; the chemical composition ratio conforms to 620≤θ≤715; θ=9.8×(36.69+160.6W) C +5.28W Mn +2.618W Ni +6.966W Mo +2.24W TiThe alloy design of the submerged arc welding wire provided by this invention, with high Mn, medium Mo, low Ti, and trace amounts of Ce and Ca, ensures that the weld metal after welding can obtain a deposited metal structure dominated by acicular ferrite under high heat input conditions, balancing strength and toughness, and meeting the welding requirements of a wide heat input range. Simultaneously, the low C, low Si, and high Ni alloy design ensures a low carbon equivalent (Ceq) and cold cracking sensitivity (Pcm) in the weld metal, and avoids the formation of the brittle phase (MA), improving the low-temperature toughness of the weld metal after high heat input welding. Furthermore, the high... The design of Ni can also reduce the brittle transition temperature of the ferrite matrix by toughening it, improve the low-temperature toughness stability range, and enhance the process adaptability of the weld metal to efficient welding. The addition of Ce has two effects: firstly, it spheroidizes inclusions such as S and P during the smelting process, and then melts into the slag along with the inclusions, thereby purifying the weld metal and improving its low-temperature toughness; secondly, in addition to some Ce entering the slag during smelting, some Ce also enters the weld metal, which can reduce the sensitivity of the weld metal to hydrogen-induced cracking; and the reasonable addition of Ca can achieve the effect of sulfide modification. The results of the embodiments show that the submerged arc welding wire provided by the present invention has excellent comprehensive performance of the deposited metal in the range of heat input of 50 to 150 kJ / cm, with high tensile strength and low temperature impact toughness, yield strength Rp0.2 / MPa: ≥460MPa, tensile strength Rm / MPa: >600MPa, elongation A / %: ≥20%, and impact absorption energy Akv-40℃ / J: ≥70J. It can be applied to the production and efficient welding manufacturing of large welded structural components in industries such as bridges, ships and buildings. Attached Figure Description

[0024] Figure 1 The image shows the microstructure of the weld metal obtained in Example 1.

[0025] Figure 2 The image shows the microstructure of the weld metal obtained in Example 1.

[0026] Figure 3 The image shows the microstructure of the weld metal obtained in Comparative Example 1.

[0027] Figure 4 The image shows the microstructure of the weld seam obtained in Comparative Example 1. Detailed Implementation

[0028] This invention provides a submerged arc welding wire suitable for high heat input welding of 50-150 kJ / cm, comprising the following chemical composition by mass percentage: C: 0.07-0.12%, Si≤0.09%, Mn: 1.70-1.95%, P≤0.012%, S≤0.005%, Ni: 0.55-1.00%, Mo: 0.40-0.58%, Ti: 0.11-0.24%, Nb≤0.05%, V: 0.03-0.04%, Ca≤0.0015%, B: 0.0005-0.0045%, Ce≤0.030%, and the balance Fe;

[0029] The chemical composition ratio of the submerged arc welding wire conforms to 620≤θ≤715;

[0030] θ = 9.8 × (36.69 + 160.6W) C +5.28W Mn +2.618W Ni +6.966W Mo +2.24W Ti ).

[0031] The submerged arc welding wire provided by this invention, suitable for high heat input welding of 50-150 kJ / cm, comprises C: 0.07-0.12%, preferably 0.08-0.11%, and more preferably 0.09-0.10% by mass percentage. In this invention, carbon has the effect of increasing the strength of the weld metal, but it also has a significant effect on reducing its toughness and crack resistance. To improve toughness and crack resistance, the carbon content should be as low as possible. However, carbon is significantly lost during submerged arc welding; therefore, to ensure appropriate strength and minimize the impact of carbon on toughness and crack resistance, the carbon content is limited to the range of 0.07-0.12%.

[0032] By mass percentage, the submerged arc welding wire provided by this invention, suitable for welding with a high heat input of 50–150 kJ / cm, contains Si ≤0.09%, preferably ≤0.08%. In this invention, silicon is an effective deoxidizing element during the welding process. When the silicon content in the weld metal is less than 0.1%, the deoxidation effect is poor, and porosity is easily formed in the weld metal; when the silicon content in the weld metal is greater than 0.6%, the toughness of the weld metal is significantly reduced. For submerged arc welding, the silicon in the weld metal after welding will be transferred from the base metal and the submerged arc welding flux, therefore, the silicon content in the welding wire composition is limited to ≤0.09%.

[0033] The submerged arc welding wire provided by this invention, suitable for high heat input welding of 50-150 kJ / cm, comprises Mn: 1.70-1.95%, preferably 1.75-1.90%, and more preferably 1.80-1.85%, by mass percentage. In this invention, adding an appropriate amount of Mn to the weld metal can increase the AF content and improve impact toughness while ensuring the strength of the weld metal. Generally, the Mn content is below 2.0%, which can improve the microstructure and mechanical properties of the weld metal. Excessive Mn, like C and P elements, easily forms segregation bands in the weld metal, causing uneven microstructure and hardness of the weld, which is detrimental to toughness. Therefore, the Mn content of the weld metal should be limited. If the Mn content is below 1.2%, the toughness of the weld metal cannot be guaranteed. Considering the large loss of manganese during high heat input submerged arc welding, the Mn content in the welding wire composition is controlled within the range of 1.70-1.95%.

[0034] By mass percentage, the submerged arc welding wire provided by this invention, suitable for welding with a high heat input of 50–150 kJ / cm, contains P ≤ 0.012%. In this invention, P is an impurity element and should be reduced as much as possible. However, metallurgical de-P removal is very costly, so the P content is limited to below 0.012%.

[0035] By mass percentage, the submerged arc welding wire provided by this invention, suitable for welding with a high heat input of 50–150 kJ / cm, contains S ≤ 0.005%. In this invention, sulfur reduces the mechanical properties of the weld, so its content, similar to P, is better the lower it is; therefore, the S content is limited to below 0.005%.

[0036] By mass percentage, the submerged arc welding wire provided by this invention, suitable for high heat input welding of 50–150 kJ / cm, comprises Ni: 0.55–1.00%, preferably 0.60–0.90%, more preferably 0.70–0.80%. In this invention, nickel is an austenite-forming element that can improve the low-temperature toughness of the weld metal. To ensure that the weld metal has a certain degree of ductility and toughness under high heat input welding conditions, the nickel content is controlled at 0.55–1.0%, thereby toughening the ferrite matrix, reducing its brittle transition temperature, and improving low-temperature toughness.

[0037] By mass percentage, the submerged arc welding wire provided by this invention, suitable for welding with a high heat input of 50–150 kJ / cm, comprises Mo: 0.40–0.58%, preferably 0.45–0.55%. In this invention, adding 0.4–0.58% Mo to the submerged arc welding wire can improve the strength and low-temperature impact toughness of the weld metal; at the same time, the added Mo can effectively reduce the phase transformation temperature of the weld metal during the cooling process after welding, thereby refining the weld metal microstructure and simultaneously expanding the formation temperature range of acicular ferrite and bainite. The refinement of the submerged arc welding wire microstructure improves the strength of the weld metal, while the promotion of acicular ferrite improves the low-temperature impact toughness.

[0038] The submerged arc welding wire provided by this invention, suitable for high heat input welding of 50–150 kJ / cm, comprises Ti: 0.11–0.24%, preferably 0.15–0.20%, by mass percentage. In this invention, the addition of Ti to the submerged arc welding wire primarily serves to disperse the oxides and nitrides it forms, effectively inhibiting austenite grain growth. Furthermore, when its volume content increases within an appropriate range, it significantly promotes the formation of acicular ferrite in the weld metal. Simultaneously, the inclusion of Ti in composite oxides with Si, Mn, Al, and Mg is beneficial for the nucleation and growth of acicular ferrite, improving the low-temperature toughness of the weld metal under high heat input. In high heat input welding, Ti burn-off is severe, so the amount of Ti added should be increased; therefore, the Ti content in the welding wire composition is controlled within the range of 0.11–0.24%.

[0039] By mass percentage, the submerged arc welding wire provided by this invention, suitable for welding with a high heat input of 50–150 kJ / cm, contains Nb ≤ 0.05%, preferably ≤ 0.04%. In this invention, the addition of appropriate amounts of Nb can significantly improve the high-temperature performance of the weld metal, and can increase the ratio of the high-temperature yield strength to the room-temperature yield strength of the weld metal, thereby improving the refractory properties of the weld metal. The main high-temperature strengthening mechanism of Nb is that it stabilizes acicular ferrite grains during high-temperature heating, inhibiting their growth, while simultaneously forming more fine, dispersed, and stable carbides, playing a precipitation strengthening role and effectively improving the high-temperature refractory properties of the weld metal. Therefore, the Nb content of the welding wire of this invention is controlled within the range of ≤ 0.05%.

[0040] By mass percentage, the submerged arc welding wire provided by this invention, suitable for welding with a high heat input of 50–150 kJ / cm, comprises V: 0.03–0.04%, preferably 0.035–0.04%. In this invention, the addition of alloying element V enhances the corrosion resistance of the deposited metal. The increased number of precipitated phases leads to an increase in the content of solid solution elements, improving the density of the passivation film on the surface of the deposited metal. Simultaneously, the large number of precipitated phases causes corrosion to occur from multiple locations, which helps to reduce the cathode area and anolyte current density during corrosion, promoting uniform corrosion of the deposited metal and enhancing its corrosion resistance. Therefore, the V content of the welding wire of this invention is controlled within the range of 0.03–0.04%.

[0041] By mass percentage, the submerged arc welding wire provided by this invention, suitable for welding with a high heat input of 50–150 kJ / cm, contains ≤0.0015% Ca, preferably ≤0.0012%. In this invention, adding an appropriate amount of Ca can spheroidize the originally strip-shaped MnS inclusions, promoting the nucleation and growth of AF (aggregate ferrite). Simultaneously, the Ca-formed CaS or CaO combines with other inclusions, inducing AF formation, thereby improving the toughness of the deposited metal. However, the Ca content should not exceed 0.0015%, otherwise coarse inclusions will form, reducing the toughness of the weld metal. Therefore, the Ca content in this welding wire is controlled at ≤0.0015%.

[0042] By mass percentage, the submerged arc welding wire provided by this invention, suitable for high heat input welding of 50-150 kJ / cm, comprises B: 0.0005-0.0045%, preferably 0.0015-0.0035%. In this invention, boron is added to the chemical composition of the raw materials of the welding wire, making it more fluid than silicon manganese steel welding wire during welding, changing the density of the weld metal of silicon manganese steel welding material, and improving the aesthetic appearance of the weld formation. The dendritic structure of the alloy begins to refine after the addition of B, and B acts as a strong modifier in the alloy. The boron-containing alloy steel welding wire has stronger corrosion resistance than silicon manganese steel welding wire, and at the same time, it can make the weld metal obtain very high toughness. Therefore, this invention controls the B content within the range of 0.0005-0.0045%.

[0043] By mass percentage, the submerged arc welding wire provided by this invention, suitable for high heat input welding of 50–150 kJ / cm, contains Ce ≤ 0.030%, preferably ≤ 0.025%. In this invention, adding trace amounts of rare earth elements to the welding wire can effectively reduce the content of inclusions such as oxides, nitrides, and sulfides, and change the morphology of these inclusions. Simultaneously, rare earth elements can improve the fluidity of the weld pool, further reducing the gas and inclusion content in the weld, and improving the metallurgical quality of the weld metal. Therefore, this invention controls the Ce content within the range of Ce ≤ 0.030%.

[0044] By weight percentage, the submerged arc welding wire provided by this invention, suitable for welding with a high heat input of 50–150 kJ / cm, includes the balance Fe. In this invention, iron is the matrix element of the welding wire.

[0045] In this invention, the submerged arc welding wire preferably contains at least one of Nb, Ca, and Ce. In this invention, Nb can significantly improve the high-temperature performance of the weld metal and increase the ratio of high-temperature yield strength to room-temperature yield strength; Ce can purify the weld metal, improving its low-temperature toughness, and reduce the weld metal's susceptibility to hydrogen-induced cracking; the appropriate addition of Ca achieves sulfide modification; by adding at least one of the above three elements, the submerged arc welding wire can possess excellent mechanical properties.

[0046] The submerged arc welding wire provided by this invention for welding with a high heat input of 50-150 kJ / cm preferably further includes Pb, Sn, As, Sb, and Bi by mass percentage, and Pb+Sn+As+Sb+Bi≤0.010%. In this invention, Pb, Sn, As, Sb, and Bi are all harmful elements, so their total mass percentage content needs to be strictly controlled within the range of ≤0.010%.

[0047] In this invention, the chemical composition ratio of the submerged arc welding wire conforms to 620≤θ≤715, preferably 630≤θ≤705, and more preferably 640≤θ≤700; wherein, θ=9.8×(36.69+160.6W) C +5.28W Mn +2.618W Ni +6.966W Mo +2.24W Ti This invention combines the transition allowance of each alloying element after high heat input welding burn-off with the strength increment caused by chemical composition, and takes into account the influence of strengthening and toughening methods such as solid solution strengthening, dislocation strengthening, precipitation and dispersion strengthening, and grain boundary strengthening on the properties of metallic materials, thereby obtaining the above-mentioned relationship. By controlling the contents of C, Mn, Ti, Ni, and Mo to satisfy the above relationship, the deposited metal obtained by submerged arc welding wire under a heat input of 50-150 kJ / cm has excellent comprehensive properties, with high tensile strength and low-temperature impact toughness.

[0048] In this invention, the submerged arc welding wire preferably further includes a copper plating layer on its surface; the thickness of the copper plating layer is preferably 0.19–0.23 μm, more preferably 0.20–0.22 μm, and even more preferably 0.20–0.21 μm. This invention avoids internal elemental oxidation by providing a copper plating layer.

[0049] The alloy design of the submerged arc welding wire provided by this invention, with high Mn, medium Mo, low Ti, and trace amounts of Ce and Ca, ensures that the weld metal can obtain a deposited metal microstructure dominated by acicular ferrite under high heat input conditions, balancing strength and toughness to meet the welding requirements of a wide heat input range. Simultaneously, the low C, low Si, and high Ni alloy design ensures a low carbon equivalent (Ceq) and low cold cracking susceptibility (Pcm) in the weld metal, and avoids the formation of the brittle phase (MA), improving the low-temperature toughness of the weld metal after high heat input welding. Furthermore, the high... The design of Ni can also reduce the brittle transition temperature of the ferrite matrix by toughening it, improve the low-temperature toughness stability range, and enhance the process adaptability of the weld metal to efficient welding. The addition of Ce has two effects: firstly, it spheroidizes inclusions such as S and P during the smelting process, and then melts into the slag along with the inclusions, thereby purifying the weld metal and improving its low-temperature toughness; secondly, in addition to some Ce entering the slag during smelting, some Ce also enters the weld metal, which can reduce the sensitivity of the weld metal to hydrogen-induced cracking; and the reasonable addition of Ca can achieve the effect of sulfide modification.

[0050] In this invention, the preferred method for preparing submerged arc welding wire suitable for high heat input welding of 50-150 kJ / cm includes: smelting and casting steel ingots according to the alloy composition of the submerged arc welding wire, then forging, rolling into wire rods, drawing into welding wires of the corresponding size, copper plating and polishing, and finally coiling and packaging into finished products. This invention does not impose specific limitations on the process parameters in the preparation method; they can be determined based on the technical knowledge of those skilled in the art. The alloy system of the submerged arc welding wire of this invention is reasonably controlled, and its wire rod smelting, rolling, and welding wire drawing processes are easy to implement, resulting in stable quality and suitability for large-scale application.

[0051] This invention provides the application of the submerged arc welding wire, which is suitable for high heat input welding of 50-150 kJ / cm, in submerged arc welding and flux copper backing method.

[0052] In this invention, the submerged arc welding wire is preferably matched with an Fe-containing basic sintered flux during application; the Fe-containing basic sintered flux is preferably a Fe-powder-MgO-SiO2-CaF2-Al2O3 system basic sintered flux. This invention does not have a specific limitation on the specific source of the Fe-containing basic sintered flux; commercially available products well-known to those skilled in the art can be used.

[0053] In this invention, the submerged arc welding is preferably a single-wire submerged arc automatic welding, a double-wire submerged arc automatic welding, or a three-wire submerged arc automatic welding, and more preferably a double-wire submerged arc automatic welding or a three-wire submerged arc automatic welding.

[0054] In this invention, the submerged arc welding wire is preferably used in the production and efficient welding manufacturing of large welded structural components in the bridge, shipbuilding and construction industries, and is more preferably used for efficient welding of Q420 to Q460qE grade steel plates under a welding heat input of 50 to 150 kJ / cm.

[0055] The submerged arc welding wire provided by this invention has a suitable heat input range of 50–150 kJ / cm. It is compatible with a dedicated Fe-containing alkaline sintered flux, exhibiting stable welding performance, good molten pool fluidity, aesthetically pleasing deposited metal formation, and excellent crack resistance during welding. This submerged arc welding wire has a simple chemical composition, high deposition efficiency, excellent low-temperature toughness, and strong adaptability to various welding heat input ranges. It is suitable for the efficient welding and manufacturing of large steel structures in fields such as bridges, ships, and buildings.

[0056] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0057] Examples 1-3 and Comparative Examples 1-3

[0058] The chemical compositions of the submerged arc welding wires provided in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1:

[0059] Table 1. Chemical composition (wt.%) of the submerged arc welding wires provided in Examples 1-3 and Comparative Examples 1-3

[0060]

[0061] The preparation methods of the submerged arc welding wires provided in Examples 1-3 and Comparative Examples 1-3 are as follows: Based on the precisely calculated welding wire composition ratio, raw materials with low P, S, gas and inclusion content are selected, the amount of alloy added is calculated, and welding wire steel is smelted in a 75kg vacuum induction furnace. After charging, melting and refining, the steel is cast into steel ingots after the composition is qualified. The steel ingots are forged into square billets and rolled into 8.5mm wire rods. The wire rods are then drawn into 5.0mm solid submerged arc welding wires through one coarse drawing and two fine drawing. The welding wire quality is stable. The surface of the welding wire is further coated with copper using a chemical copper plating method, with a copper plating thickness of 0.20μm, to obtain the submerged arc welding wire.

[0062] The submerged arc welding wires provided in Examples 1-3 and Comparative Examples 1-3 were subjected to single-wire deposited metal tests according to the welding process parameters in Table 2. The welding heat input was 50 kJ / cm, and a specially formulated Fe powder-MgO-SiO2-CaF2-Al2O3 alkaline sintering flux was used for welding. The layer temperature was controlled to be no more than 160℃.

[0063] Table 2. Bevel type and process parameters for the single-wire metal deposition test.

[0064]

[0065] Examples 4-6 and Comparative Examples 4-6

[0066] The chemical compositions of the submerged arc welding wires provided in Examples 4-6 and Comparative Examples 4-6 are shown in Table 3:

[0067] Table 3 Chemical composition (wt.%) of the submerged arc welding wires provided in Examples 4-6 and Comparative Examples 4-6

[0068]

[0069] The preparation methods of the submerged arc welding wires provided in Examples 4-6 and Comparative Examples 4-6 are the same as those in Example 1.

[0070] The submerged arc welding wires provided in Examples 4-6 and Comparative Examples 4-6 were subjected to a double-wire deposited metal test according to the welding process parameters in Table 4. The welding heat input was 100 kJ / cm, and a specially formulated Fe powder-MgO-SiO2-CaF2-Al2O3 alkaline sintering flux was used for welding. The layer temperature was controlled to be no more than 160℃.

[0071] Table 4. Bevel type and process parameters for monofilament metal deposition test.

[0072]

[0073] Examples 7-9 and Comparative Examples 7-9

[0074] The chemical compositions of the submerged arc welding wires provided in Examples 7-9 and Comparative Examples 7-9 are shown in Table 5:

[0075] Table 5. Chemical composition (wt.%) of the submerged arc welding wires provided in Examples 7-9 and Comparative Examples 7-9.

[0076]

[0077] The preparation methods of the submerged arc welding wires provided in Examples 7-9 and Comparative Examples 7-9 are the same as those in Example 1.

[0078] The submerged arc welding wires provided in Examples 7-9 and Comparative Examples 7-9 were subjected to a three-wire fused metal test according to the welding process parameters in Table 6. The welding heat input was 150 kJ / cm, and a specially formulated Fe powder-MgO-SiO2-CaF2-Al2O3 alkaline sintering flux was used for welding. The layer temperature was controlled to be no more than 160℃.

[0079] Table 6. Bevel type and process parameters for the single-wire metal deposition test.

[0080]

[0081] Performance Testing: Samples were taken from the welded fusion metal, ensuring that the entire parallel length consisted of fusion metal. The sample size and test methods were performed according to GB / T 228. Impact test specimens were cut from the center of the fusion metal, with the longitudinal axis of the specimen perpendicular to the length of the fusion metal, the notched surface perpendicular to the fusion metal surface, and the notch axis located at the center of the fusion metal. The specimen size was 10×10×55mm, and the impact test method was performed according to GB / T 229. The tensile and impact test results of the fusion metal are shown in Table 7, with the values ​​in parentheses representing averages.

[0082] Table 7 Mechanical properties of weld metal obtained from the submerged arc welding wires provided in Examples 1-9 and Comparative Examples 1-9

[0083]

[0084] As shown in Table 7, the submerged arc welding wire provided by this invention can meet various specifications for deposited metal within a heat input range of 50-150 kJ / cm, exhibiting excellent comprehensive performance, high tensile strength and low-temperature impact toughness, yield strength Rp0.2 / MPa: ≥460MPa, tensile strength Rm / MPa: >600MPa, elongation A / %: ≥20%, and impact absorption energy Akv-40℃ / J: ≥70J. It can be applied to the production and efficient welding manufacturing of large welded structural components in industries such as bridges, ships, and buildings.

[0085] Figure 1 and Figure 2 These are microstructure images of different parts of the weld seam obtained in Example 1. Figure 1 and Figure 2 It can be seen that the microstructure formed by the welding wire provided by the present invention is mainly composed of fine acicular ferrite and granular bainite, and the microstructure is evenly distributed; therefore, even under a high heat input of 150 kJ / cm, it can still obtain excellent tensile strength and low-temperature impact toughness.

[0086] Figure 3 and Figure 4 These are microstructure images of different parts of the weld metal obtained in Comparative Example 1. Figure 3 and Figure 4 It can be seen that the microstructure is mainly composed of proeutectoid ferrite, granular bainite and a small amount of acicular ferrite; the microstructure is relatively coarse and unevenly distributed, so the tensile strength and low-temperature impact toughness are both low.

[0087] pass Figures 1-4The comparison shows that the submerged arc welding wire provided by the present invention is more suitable for welding with a high heat input of 50 to 150 kJ / cm.

[0088] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A submerged arc welding wire suitable for high heat input welding of 50-150 kJ / cm, comprising the following chemical composition by mass percentage: C: 0.07-0.12%, Si≤0.09%, Mn: 1.70-1.95%, P≤0.012%, S≤0.005%, Ni: 0.55-1.00%, Mo: 0.40-0.58%, Ti: 0.11-0.24%, Nb≤0.05%, V: 0.03-0.04%, Ca≤0.0015%, B: 0.0005-0.0045%, Ce≤0.030%, and the balance Fe; The chemical composition ratio of the submerged arc welding wire conforms to 620≤θ≤715; θ = 9.8 x (36.69 + 160.6W C + 5.28W Mn + 2.618W Ni + 6.966W Mo + 2.24W Ti ).

2. The submerged arc welding wire suitable for high heat input welding of 50-150 kJ / cm as described in claim 1, characterized in that, The chemical composition, by mass percentage, includes the following: C: 0.08–0.11%, Si ≤ 0.09%, Mn: 1.75–1.90%, P ≤ 0.012%, S ≤ 0.005%, Ni: 0.60–0.90%, Mo: 0.40–0.58%, Ti: 0.11–0.24%, Nb ≤ 0.05%, V: 0.03–0.04%, Ca ≤ 0.0015%, B: 0.0005–0.0045%, Ce ≤ 0.030%, and the balance Fe.

3. The submerged arc welding wire suitable for high heat input welding of 50-150 kJ / cm as described in claim 2, characterized in that, The chemical composition, by mass percentage, includes the following: C: 0.08–0.11%, Si ≤ 0.09%, Mn: 1.80–1.85%, P ≤ 0.012%, S ≤ 0.005%, Ni: 0.70–0.80%, Mo: 0.45–0.55%, Ti: 0.15–0.20%, Nb ≤ 0.05%, V: 0.03–0.04%, Ca ≤ 0.0015%, B: 0.0015–0.0035%, Ce ≤ 0.030%, and the balance Fe.

4. The submerged arc welding wire suitable for high heat input welding of 50-150 kJ / cm as described in claim 1, characterized in that, The chemical composition ratio of the submerged arc welding wire conforms to 630≤θ≤705.

5. The submerged arc welding wire suitable for high heat input welding of 50-150 kJ / cm as described in claim 4, characterized in that, The chemical composition ratio of the submerged arc welding wire conforms to 640≤θ≤700.

6. The submerged arc welding wire suitable for high heat input welding of 50-150 kJ / cm as described in claim 1, characterized in that, The submerged arc welding wire contains at least one of Nb, Ca, and Ce.

7. The submerged arc welding wire suitable for high heat input welding of 50-150 kJ / cm as described in claim 1, characterized in that, The submerged arc welding wire also includes Pb, Sn, As, Sb and Bi, and by mass percentage, Pb+Sn+As+Sb+Bi≤0.010%.

8. The submerged arc welding wire suitable for high heat input welding of 50-150 kJ / cm as described in claim 1, characterized in that, The submerged arc welding wire also includes a copper plating layer on its surface, the thickness of which is 0.19–0.23 μm.

9. The application of the submerged arc welding wire of any one of claims 1 to 8, suitable for welding with a high heat input of 50 to 150 kJ / cm, in submerged arc welding and flux copper backing method.

10. The application according to claim 9, characterized in that, The submerged arc welding wire is used in the production and efficient welding manufacturing of large welded structural components in the bridge, shipbuilding and construction industries.

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