Solid gas shield welding wire for welding 1000MPa-grade high-strength steel

Abstract

The invention provides a solid gas shielded welding wire for welding 1000MPa-grade high-strength steel. The solid gas shielded welding wire comprises the following components in percentage by weight: 0.06-0.10 wt% of C; si: 0.30 to 0.60 wt%; mn: 0.85 to 1.25 wt%; 0.60 to 0.80 wt% of Mo; ni: 8.4 to 9.4 wt%; 0.014 to 0.050 wt% of Ti (titanium); 0.010 wt% to 0.030 wt% of Al; p is less than 0.010 wt%; s is less than 0.010 wt%; less than or equal to 0.10 wt% of Cr; v: less than or equal to 0.040 wt%; cu: less than or equal to 0.03 wt%, and the balance Fe and inevitable impurities. According to the welding wire, a Mn-Ni-Mo alloy system is designed, and the components of the welding wire are optimized, so that the strength, toughness and manufacturability are synergistically improved.

Description

Technical Field

[0001] This invention belongs to the field of welding materials technology, and in particular relates to a solid gas-shielded welding wire for welding 1000MPa grade high-strength steel. Background Technology

[0002] With the development of high-end equipment manufacturing industries such as construction machinery, hydropower, mining machinery, pipeline transportation, and offshore platforms, the requirements for material strength are constantly increasing. Construction machinery is developing towards larger size, lighter weight, and higher parameters, making the use of high-strength steel in the manufacture of large construction machinery structural components a trend. 600MPa-grade high-strength steel is gradually being phased out of the manufacture of large construction machinery structural components, while 890MPa-grade and above steel has become the mainstream demand. To meet the higher requirements for strength, toughness, and high wear resistance of key structural components in construction machinery, 1000MPa-grade and above high-strength steel has been developed and used, with its usage increasing significantly in recent years, showing broad application prospects in many fields. For example, in the hydropower sector, 1000MPa-grade steel has achieved significant breakthroughs in hydropower projects. 1000MPa-grade high-strength steel plates have been successfully applied in the Tiantai pumped storage power station in Zhejiang Province, marking the first large-scale application of this technology in the domestic hydropower industry. As my country's hydropower units develop towards larger head and higher displacement, higher demands are placed on the strength, toughness, and high plasticity of steel. 1000MPa grade steel is expected to see wider application in key pressure-bearing components of subsequent large-scale hydropower projects, ultra-high head pumped storage power stations, and large-capacity impulse generator units. In the automotive sector, this grade of steel can be used in car body structural components. For example, a 1.2mm thick B-pillar reinforcement made of 1000MPa grade steel is 30% thinner than traditional materials, while reducing side impact intrusion by 22mm. This reduces overall vehicle weight without sacrificing safety, contributing to vehicle lightweighting, improved energy efficiency, and extended driving range. In the construction machinery sector, 1000MPa grade steel also performs exceptionally well. For instance, excavator booms made of 1000MPa grade steel, while maintaining the same load-bearing capacity, have reduced structural weight, saving diesel consumption, and allowing for better control of platform sway, thus improving equipment performance and stability. In the field of special equipment, the pressure hulls of submersibles and other equipment are made of 1000MPa grade steel, which makes the hull more resistant to deformation when subjected to water pressure, thus improving the safety and reliability of the submersible.

[0003] Welding is an indispensable processing and manufacturing step in the promotion and application of low-alloy high-strength steel. Developing welding materials that match low-alloy high-strength steel and optimizing welding processes are key to obtaining high-quality welded joints. To meet the welding requirements of 1000MPa grade steel, the industry is actively conducting research. Currently, the demand for welding 1000MPa grade high-strength steel in the engineering field is increasing. Existing solid welding wires have two major problems: First, the weld metal has poor strength-toughness matching. While meeting the 1000MPa grade tensile strength, the low-temperature impact toughness (-40℃) is often below 40J, making it difficult to adapt to cold and impact load conditions. Second, the welding process is poor. During welding, problems such as large spatter and poor weld formation are prone to occur, and the requirements for bevel cleaning are stringent, resulting in low welding efficiency and high cost. Summary of the Invention

[0004] In view of this, the present invention aims to propose a solid gas-shielded welding wire for welding 1000MPa grade high-strength steel. It is designed with a Mn-Ni-Mo alloy system, and the tensile strength of the weld metal is ≥1000MPa. At the same time, it has excellent low-temperature impact toughness, with an impact energy of ≥60J at -40℃. It also has good welding process performance, can adapt to high-current welding, reduce spatter and defects, and improve welding efficiency and quality.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] A solid gas-shielded welding wire for welding 1000MPa grade high-strength steel, wherein the chemical composition of the welding wire by weight percentage includes: C: 0.06-0.10wt%; Si: 0.30-0.60wt%; Mn: 0.85-1.25wt%; Mo: 0.60-0.80wt%; Ni: 8.4-9.4wt%; Ti: 0.014-0.050wt%; Al: 0.010-0.030wt%; P < 0.010wt%; S < 0.010wt%; Cr: ≤ 0.10wt%; V: ≤ 0.040wt%; Cu: ≤ 0.03wt%, with the balance being Fe and unavoidable impurities.

[0007] Furthermore, the harmful element Sb+Sn+As+Bi≤0.008wt%.

[0008] Furthermore, the oxygen, nitrogen, and hydrogen content is O≤0.0050wt%, N≤0.0060wt%, and H≤0.0003wt%.

[0009] Furthermore, the chemical composition of the welding wire, by weight percentage, includes: C: 0.071 wt%; Si: 0.46 wt%; Mn: 0.95 wt%; Mo: 0.67 wt%; Ni: 8.9 wt%; Ti: 0.045 wt%; Al: 0.011 wt%; P: 0.0025 wt%; S: 0.0040 wt%; Cr: 0.010 wt%; V: 0.010 wt%; Cu: 0.010 wt%; O: 0.0021 wt%; N: 0.0029 wt%; H: 0.00027 wt%, with the balance being Fe and unavoidable impurities.

[0010] Furthermore, the chemical composition of the welding wire, by weight percentage, includes: C: 0.085 wt%; Si: 0.56 wt%; Mn: 1.16 wt%; Mo: 0.75 wt%; Ni: 9.3 wt%; Ti: 0.047 wt%; Al: 0.013 wt%; P: 0.0035 wt%; S: 0.0041 wt%; Cr: 0.010 wt%; V: 0.010 wt%; Cu: 0.010 wt%; O: 0.0025 wt%; N: 0.0024 wt%; H: 0.00023 wt%, with the balance being Fe and unavoidable impurities.

[0011] Furthermore, the chemical composition of the welding wire, by weight percentage, includes: C: 0.069 wt%; Si: 0.48 wt%; Mn: 0.88 wt%; Mo: 0.61 wt%; Ni: 8.6 wt%; Ti: 0.039 wt%; Al: 0.017 wt%; P: 0.0025 wt%; S: 0.0049 wt%; Cr: 0.010 wt%; V: 0.010 wt%; Cu: 0.010 wt%; O: 0.0026 wt%; N: 0.0027 wt%; H: 0.00028 wt%, with the balance being Fe and unavoidable impurities.

[0012] This invention also provides a method for preparing solid gas-shielded welding wire for 1000MPa grade high-strength steel welding as described above. The method is as follows: steelmaking is carried out in an industrial converter, and a top-bottom composite blowing process is used to control the S and P at the end of the smelting process to a low level; after deoxidation and alloying, the steel is refined in an LF furnace to produce molten steel with the required composition; the molten steel is cast into a continuous casting billet by a special casting machine under full protection, and the continuous casting billet is rolled into wire rod by a high-speed twist-free rolling mill; after annealing, the wire rod is processed into finished welding wire by rough drawing and fine drawing.

[0013] Furthermore, the diameter of the wire rod is 5.5 mm.

[0014] Furthermore, the diameter of the finished welding wire is 1.2mm.

[0015] The welding wire described in this invention is a high-strength steel welding wire based on the Mn-Ni-Mo alloy system. Through the synergistic effect of multiple elements, it achieves a comprehensive balance of high strength, high toughness, and low crack sensitivity in the weld metal. Ni (nickel) is the core element in the design, and its performance regulation, combined with elements such as C (carbon), Mn (manganese), and Mo (molybdenum), meets the welding requirements of 1000MPa through composite mechanisms such as solid solution strengthening, microstructure regulation, and precipitation strengthening.

[0016] Ni is a key element in this invention that determines the synergistic balance between weld toughness and strength, and it is present in high amounts. It mainly functions through a dual mechanism of solid solution strengthening and microstructure regulation. Ni is a face-centered cubic (FCC) structural element, which can form an infinite solid solution with iron (body-centered cubic BCC or FCC). When its atoms are incorporated into the iron matrix, they induce lattice distortion, creating additional resistance to moving dislocations and hindering dislocation slip, thereby increasing yield strength and tensile strength (in low-alloy high-strength steel, every 1% increase in Ni can increase tensile strength by 30-50 MPa, with the effect increasing with content within the solid solubility range). Simultaneously, Ni can lower the transformation temperature from austenite to ferrite, promoting the formation of fine-grained structures (such as acicular ferrite and fine-grained bainite). According to the Hall-Page relation, the finer the grains, the stronger the resistance of grain boundaries to dislocations, and the higher the strength. A large amount of Ni dissolved in the ferrite matrix can significantly reduce the ductile-brittle transition temperature of the weld and improve low-temperature toughness. At the same time, Ni can inhibit the formation of harmful low-strength structures such as coarse Widmanstätten structure and network cementite, reduce microstructure inhomogeneity, and further ensure toughness stability.

[0017] Ni, when added alone, offers limited strength enhancement and needs to be combined with C, Mn, and Mo. C is one of the core elements ensuring 1000 MPa strength, enhancing dislocation resistance in the matrix through solid solution strengthening, thereby increasing strength. However, excessively high levels significantly increase weld hardenability, leading to the formation of hard and brittle martensite during cooling, greatly increasing cold cracking susceptibility and reducing toughness. Conversely, excessively low levels result in insufficient solid solution strengthening, failing to meet the 1000 MPa strength standard. Mo, as a strong carbide-forming element, promotes the uniform precipitation of carbide (such as Mo2C) strengthening phases in weld wires with high Ni content, thus enhancing strength through solid solution strengthening. It also strongly inhibits pearlite transformation, promotes bainite formation, and refines grain size. Simultaneously, it improves weld hot strength and tempering stability, preventing strength degradation under high-temperature conditions. Mn enhances strength through solid solution strengthening, and when used as a deoxidizer, it reduces the oxygen content of the weld, decreases oxide inclusions, and improves weld purity. It combines with sulfur to form manganese sulfide, which inhibits sulfur-induced hot cracking. At the same time, it can lower the critical transformation temperature of austenite, promote the formation of acicular ferrite, refine grains, and synergistically optimize strength and toughness. Meanwhile, the synergistic effect of Ni and Mn can expand the austenite region and optimize the grain refinement effect.

[0018] Simultaneously, the content of silicon (Si) and impurity elements must be controlled. Si acts as a deoxidizer, reducing the oxygen content of the weld and playing a crucial role in preventing CO porosity. It also assists in improving strength through solid solution strengthening. S readily forms low-melting-point sulfides, which can trigger hot cracking during weld solidification; P reduces weld toughness and increases cold brittleness. Therefore, the content of S and P must be strictly controlled to ensure weld purity.

[0019] To achieve better performance and process effects, Ti and Al, two trace elements, are added to the welding wire. Ti has a strong affinity for oxygen and nitrogen, and can effectively deoxidize and denitrify. The resulting titanium nitride and titanium oxide fine particles can act as nucleation sites for acicular ferrite, refining the grain and simultaneously improving strength and toughness. Al is a strong deoxidizer that can refine the grain and improve impact toughness; at the same time, it can reduce the burn-off of other alloying elements (such as Ni and Mo) and ensure compositional stability.

[0020] Through the precise proportioning of the above elements (Ni as the core, C, Mn, and Mo as the main strengthening agents, Si as an auxiliary agent, Ti and Al as trace elements, and S and P as strictly controlled impurities), each element forms a composite mechanism of "solid solution strengthening + fine grain strengthening + precipitation strengthening": it achieves 1000MPa-level strength through the synergy of C, Mn, Mo, and Ni, and ensures excellent low-temperature toughness through the regulation of Ni, Ti, and Al. At the same time, it controls the content of C, S, and P to reduce crack sensitivity. Ultimately, the solid gas-shielded welding wire of the Mn-Ni-Mo system meets the welding requirements of 1000MPa-level high-strength steel, achieving a unity of high strength, high toughness, and good welding process performance.

[0021] Compared with existing technologies, the solid gas-shielded welding wire for welding 1000MPa grade high-strength steel described in this invention has the following advantages:

[0022] (1) The solid gas-shielded welding wire for welding 1000MPa grade high-strength steel described in this invention has excellent welding process performance, good arc stability, and can adapt to high-current welding, thus improving welding efficiency and quality. During welding, there is minimal spatter, good arc stability, excellent molten metal spreadability, aesthetically pleasing weld formation, good all-position operability, and it can adapt to high-current welding, improving welding efficiency and quality. The X-ray flaw detection level reaches Level I.

[0023] (2) The yield strength Rel of the solid gas-shielded welding wire for welding 1000MPa grade high-strength steel described in this invention is ≥870MPa, the tensile strength Rm is ≥960MPa, the elongation is ≥12%, and the impact energy at -40℃ is ≥47J.

[0024] (3) The solid gas-shielded welding wire for welding 1000MPa grade high-strength steel described in this invention can replace imported welding wire, significantly improve welding quality, and has significant economic and social benefits.

[0025] (4) The solid gas-shielded welding wire for welding 1000MPa grade high-strength steel described in this invention is smelted in an industrial converter, rolled by a high-speed twist-free rolling mill, and drawn into finished welding wire, which is easy to implement in production. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0027] Figure 1 The image shows the appearance of the solid gas-shielded welding wire for welding 1000MPa high-strength steel prepared in Example 1 of the present invention after welding.

[0028] Figure 2 X-ray flaw detection after welding of solid gas-shielded welding wire for welding 1000MPa grade high-strength steel prepared in Example 1 of the present invention. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] A solid gas-shielded welding wire for welding 1000MPa grade high-strength steel, wherein the chemical composition of the welding wire by weight percentage includes: C: 0.071wt%; Si: 0.46wt%; Mn: 0.95wt%; Mo: 0.67wt%; Ni: 8.9wt%; Ti: 0.045wt%; Al: 0.011wt%; P: 0.0025wt%; S: 0.0040wt%; Cr: 0.010wt%; V: 0.010wt%; Cu: 0.010wt%; O: 0.0021wt%; N: 0.0029wt%; H: 0.00027wt%, Sb+Sn+As+Bi≤0.008wt%, and the balance being Fe and unavoidable impurities.

[0033] The preparation method of the solid gas-shielded welding wire for welding the above-mentioned 1000MPa grade high-strength steel is as follows: steelmaking is carried out in an industrial converter, and the raw materials selected are pure iron, electrolytic manganese, electrolytic nickel, electrolytic molybdenum, industrial pure titanium, etc. Desulfurized molten iron is used to control the sulfur content of the molten iron entering the furnace, so as to fully ensure the cleanliness of the weld metal. Raw materials with low S and P content are selected. The top and bottom composite blowing process is adopted to control the S and P at the end of the smelting to a low level. After deoxidation and alloying, the LF furnace ladle refining process is used to smelt molten steel with the required composition. The molten steel is cast into continuous casting billets by a special type casting machine under full protection. The continuous casting billets are rolled into Φ5.5mm wire rods by a high-speed twist-free rolling mill.

[0034] Due to the high strength of the raw materials for welding wire, an annealing process is considered based on the chemical composition to eliminate work hardening and soften the metal. After annealing, the wire rod is produced into Φ1.2mm copper-free welding wire through rough drawing, fine drawing, and sizing.

[0035] Example 2

[0036] A solid gas-shielded welding wire for welding 1000MPa grade high-strength steel, wherein the chemical composition of the welding wire by weight percentage includes: C: 0.085wt%; Si: 0.56wt%; Mn: 1.16wt%; Mo: 0.75wt%; Ni: 9.3wt%; Ti: 0.047wt%; Al: 0.013wt%; P: 0.0035wt%; S: 0.0041wt%; Cr: 0.010wt%; V: 0.010wt%; Cu: 0.010wt%; O: 0.0025wt%; N: 0.0024wt%; H: 0.00023wt%, Sb+Sn+As+Bi≤0.008wt%, and the balance being Fe and unavoidable impurities.

[0037] The preparation method is the same as in Example 1.

[0038] Example 3

[0039] A solid gas-shielded welding wire for welding 1000MPa grade high-strength steel, wherein the chemical composition of the welding wire by weight percentage includes: C: 0.069wt%; Si: 0.48wt%; Mn: 0.88wt%; Mo: 0.61wt%; Ni: 8.6wt%; Ti: 0.039wt%; Al: 0.017wt%; P: 0.0025wt%; S: 0.0049wt%; Cr: 0.010wt%; V: 0.010wt%; Cu: 0.010wt%; O: 0.0026wt%; N: 0.0027wt%; H: 0.0028wt%, Sb+Sn+As+Bi≤0.008wt%, and the balance being Fe and unavoidable impurities.

[0040] The preparation method is the same as in Example 1.

[0041] Comparative Example 1

[0042] A solid gas-shielded welding wire for welding 1000MPa grade high-strength steel, wherein the chemical composition of the welding wire by weight percentage includes: C: 0.072wt%; Si: 0.46wt%; Mn: 0.70wt%; Mo: 0.55wt%; Ni: 7.9wt%; Ti: 0.031wt%; Al: 0.015wt%; P: 0.0026wt%; S: 0.0039wt%; Cr: 0.010wt%; V: 0.010wt%; Cu: 0.010wt%; O: 0.0023wt%; N: 0.0028wt%; H: 0.00016wt%, Sb+Sn+As+Bi≤0.008wt%, and the balance being Fe and unavoidable impurities.

[0043] The preparation method is the same as in Example 1.

[0044] Comparative Example 2

[0045] A solid gas-shielded welding wire for welding 1000MPa grade high-strength steel, wherein the chemical composition of the welding wire by weight percentage includes: C: 0.073wt%; Si: 0.51wt%; Mn: 1.32wt%; Mo: 0.85wt%; Ni: 8.6wt%; Ti: 0.032wt%; Al: 0.016wt%; P: 0.0036wt%; S: 0.0037wt%; Cr: 0.010wt%; V: 0.010wt%; Cu: 0.010wt%; O: 0.0023wt%; N: 0.0025wt%; H: 0.00020wt%, Sb+Sn+As+Bi≤0.008wt%, and the balance being Fe and unavoidable impurities.

[0046] The preparation method is the same as in Example 1.

[0047] Comparative Example 3

[0048] A solid gas-shielded welding wire for welding 1000MPa grade high-strength steel, wherein the chemical composition of the welding wire by weight percentage includes: C: 0.069wt%; Si: 0.48wt%; Mn: 0.85wt%; Mo: 0.65wt%; Ni: 9.8wt%; Ti: 0.032wt%; Al: 0.016wt%; P: 0.0036wt%; S: 0.0037wt%; Cr: 0.010wt%; V: 0.010wt%; Cu: 0.010wt%; O: 0.0023wt%; N: 0.0027wt%; H: 0.00019wt%, Sb+Sn+As+Bi≤0.008wt%, and the balance being Fe and unavoidable impurities.

[0049] The preparation method is the same as in Example 1.

[0050] Comparative Example 4

[0051] A solid gas-shielded welding wire for welding 1000MPa grade high-strength steel, wherein the chemical composition of the welding wire by weight percentage includes: C: 0.072wt%; Si: 0.53wt%; Mn: 0.87wt%; Mo: 0.68wt%; Ni: 10.5wt%; Ti: 0.035wt%; Al: 0.026wt%; P: 0.0035wt%; S: 0.0033wt%; Cr: 0.010wt%; V: 0.010wt%; Cu: 0.010wt%; O: 0.0024wt%; N: 0.0022wt%; H: 0.00017wt%, Sb+Sn+As+Bi≤0.008wt%, and the balance being Fe and unavoidable impurities.

[0052] The preparation method is the same as in Example 1.

[0053] Comparative Example 5

[0054] A solid gas-shielded welding wire for welding 1000MPa grade high-strength steel, wherein the chemical composition of the welding wire by weight percentage includes: C: 0.072wt%; Si: 0.47wt%; Mn: 0.94wt%; Mo: 0.68wt%; Ni: 8.95wt%; Ti: 0.046wt%; Al: 0.017wt%; P: 0.0031wt%; S: 0.0031wt%; Cr: 0.010wt%; V: 0.010wt%; Cu: 0.010wt%; O: 0.0022wt%; N: 0.0075wt%; H: 0.00018wt%, Sb+Sn+As+Bi≤0.008wt%, and the balance being Fe and unavoidable impurities.

[0055] The preparation method is the same as in Example 1.

[0056] The welding wires prepared in the above embodiments and comparative examples were subjected to welding tests on the mechanical properties of the deposited metal using an argon-rich gas mixture of 80% Ar + 20% CO2. The welding current and voltage were 260A / 28V, the welding speed was 6-7mm / s, and the interpass temperature was 150℃. The mechanical properties of the weld metal deposited by the welding wires are shown in Table 1.

[0057] Table 1 Mechanical properties of the deposited metal

[0058]

[0059] Table 1 shows that in Comparative Example 1, the strength of the weld metal could not meet the requirements when the contents of Mn, Ni, and Mo did not meet the standards. In Comparative Example 2, increasing the contents of Mn and Mo alone improved the strength, but the impact toughness was poor. In Comparative Example 3, increasing the content of Ni alone had limited effect on improving the mechanical strength of the weld metal. In Comparative Example 4, further increasing the Ni content had limited effect on improving the mechanical strength of the weld metal and increased the cost of raw materials. In Comparative Example 5, a higher N content significantly improved the strength, but had an adverse effect on the plasticity and impact toughness of the weld metal.

[0060] The welding wires prepared in Examples 1-3 exhibit excellent welding process performance, good arc stability, and adaptability to high-current welding, thus improving welding efficiency and quality. During welding, spatter is minimal, arc stability is good, molten metal spread is excellent, weld formation is aesthetically pleasing, and all-position operability is good. They are also adaptable to high-current welding, further enhancing welding efficiency and quality.

[0061] Figure 1 The image shows the appearance of the solid gas-shielded welding wire for welding 1000MPa high-strength steel prepared in Example 1 after welding. It can be seen from the image that the weld bead of the wire is aesthetically pleasing, and the welding wires prepared in Examples 2-3 can achieve the same effect.

[0062] Figure 2 The image shows the X-ray flaw detection image after welding of the solid gas-shielded welding wire for welding 1000MPa high-strength steel prepared in Example 1 of this invention. The level reaches Level I, and the welding wires prepared in Examples 2-3 can reach the same level.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A solid gas-shielded welding wire for welding 1000MPa grade high-strength steel, characterized in that: The chemical composition of the welding wire, by weight percentage, includes: C: 0.06-0.10 wt%; Si: 0.30-0.60 wt%; Mn: 0.85-1.25 wt%; Mo: 0.60-0.80 wt%; Ni: 8.4-9.4 wt%; Ti: 0.014-0.050 wt%; Al: 0.010-0.030 wt%; P < 0.010 wt%; S < 0.010 wt%; Cr: ≤ 0.10 wt%; V: ≤ 0.040 wt%; Cu: ≤ 0.03 wt%, with the balance being Fe and unavoidable impurities.

2. The solid gas-shielded welding wire for welding 1000MPa grade high-strength steel according to claim 1, characterized in that: The content of harmful elements Sb+Sn+As+Bi ≤ 0.008wt%.

3. The solid gas-shielded welding wire for welding 1000MPa grade high-strength steel according to claim 1, characterized in that: The oxygen, nitrogen, and hydrogen content is O≤0.0050wt%, N≤0.0060wt%, and H≤0.0003wt%.

4. The solid gas-shielded welding wire for welding 1000MPa grade high-strength steel according to claim 1, characterized in that: The chemical composition of the welding wire, by weight percentage, includes: C: 0.071 wt%; Si: 0.46 wt%; Mn: 0.95 wt%; Mo: 0.67 wt%; Ni: 8.9 wt%; Ti: 0.045 wt%; Al: 0.011 wt%; P: 0.0025 wt%; S: 0.0040 wt%; Cr: 0.010 wt%; V: 0.010 wt%; Cu: 0.010 wt%; O: 0.0021 wt%; N: 0.0029 wt%; H: 0.00027 wt%, with the balance being Fe and unavoidable impurities.

5. The solid gas-shielded welding wire for welding 1000MPa grade high-strength steel according to claim 1, characterized in that: The chemical composition of the welding wire, by weight percentage, includes: C: 0.085 wt%; Si: 0.56 wt%; Mn: 1.16 wt%; Mo: 0.75 wt%; Ni: 9.3 wt%; Ti: 0.047 wt%; Al: 0.013 wt%; P: 0.0035 wt%; S: 0.0041 wt%; Cr: 0.010 wt%; V: 0.010 wt%; Cu: 0.010 wt%; O: 0.0025 wt%; N: 0.0024 wt%; H: 0.00023 wt%, with the balance being Fe and unavoidable impurities.

6. The solid gas-shielded welding wire for welding 1000MPa grade high-strength steel according to claim 1, characterized in that: The chemical composition of the welding wire, by weight percentage, includes: C: 0.069 wt%; Si: 0.48 wt%; Mn: 0.88 wt%; Mo: 0.61 wt%; Ni: 8.6 wt%; Ti: 0.039 wt%; Al: 0.017 wt%; P: 0.0025 wt%; S: 0.0049 wt%; Cr: 0.010 wt%; V: 0.010 wt%; Cu: 0.010 wt%; O: 0.0026 wt%; N: 0.0027 wt%; H: 0.00028 wt%, with the balance being Fe and unavoidable impurities.

7. A method for preparing a solid gas-shielded welding wire for welding 1000MPa grade high-strength steel as described in any one of claims 1-6, characterized in that: The method is as follows: steelmaking is carried out in an industrial converter, and a top-bottom combined blowing process is used to control the S and P at the end of the smelting process at a low level; after deoxidation and alloying, the LF furnace ladle refining process is used to smelt molten steel with the required composition; the molten steel is cast into continuous casting billets by a special type casting machine under full protection, and the continuous casting billets are rolled into wire rods by a high-speed twist-free rolling mill; after annealing, the wire rods are processed into finished welding wires by rough drawing and fine drawing.

8. The method for preparing solid gas-shielded welding wire for welding 1000MPa grade high-strength steel according to claim 7, characterized in that: The diameter of the wire rod is 5.5mm.

9. The method for preparing solid gas-shielded welding wire for welding 1000MPa grade high-strength steel according to claim 7, characterized in that: The diameter of the finished welding wire is 1.2mm.

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