Ultrahigh-strength gas shielded welding wire

Abstract

The application discloses a kind of superhigh strength gas shielded welding wire, the filling rate of medicine core in the welding wire is 16~20%, medicine core is mixed by the powder of two components A+B, A is alloy powder, B is MnO powder;Relative to the total mass of welding wire, the mass percentage of MnO powder is 0.01~0.04%, the mass percentage of A alloy powder component is C:0.04~0.08%, Si:0.2~0.5%, Mn:2.0~3.0%, Ni:2.5~3.5%, Cr:0.1~0.3%, Mo:0.6~1.0%, Ti:0.01~0.04%, B:0.002~0.004%, S:0.002~0.005% and the like.The welding wire uses low silicon, high Mn, high Ni alloy matching, and adds MnO powder, the tensile strength of deposited metal is not less than 1200MPa, and the impact energy at-40℃ is not less than 47J.

Description

Technical Field

[0001] This invention belongs to the field of welding materials technology, specifically relating to an ultra-high strength gas-shielded welding wire. Background Technology

[0002] In recent years, with the rise of large-scale projects in various fields in my country, construction machinery and equipment have gradually developed towards the "three highs and one large" direction of "high-end, high-tech content, high added value, and large tonnage". In order to improve the performance of machinery and equipment to meet the needs of various construction projects to the greatest extent, while requiring a reduction in their own weight, energy consumption, and costs, the strength level of steel used in construction machinery is constantly increasing, and the demand for high-strength and high-toughness welding materials is also growing.

[0003] Currently, domestic steel mills have successfully developed high-strength steel varieties with tensile strengths exceeding 1200 MPa, which are widely used in related welded structures. However, the research and development of welding materials lags behind, making it difficult to meet market demand. For example, the patent CN114769939B, "A Low-Cost Welding Wire for Laser Welding of Ultra-High-Strength Steel," achieves a joint strength of over 800 MPa after welding of hot-formed cold-rolled plates, but it is only applicable to laser welding. The patent with publication number CN 104785955 A, entitled "A Gas-Shielded Welding Wire for Ultra-High Strength Steel and Weld Metal", discloses a welding wire containing, by weight percentage, C: 0.03-0.10, Si: 0.25-0.45, Mn: 1.60-1.90, S≤0.01, P≤0.01, Ni: 2.80-5.20, Cr: 0.50-2.50, Mo: 0.3-0.8, Nb: 0.02-0.15, Ti: 0.05-0.2, Zr: 0.01-0.20, with the balance being Fe and impurity elements. After mixed gas shielded welding, a weld metal with a tensile strength ≥1000MPa and a yield strength ≥850MPa can be obtained; however, its strength does not reach 1200MPa. Patent CN115673601A, "A 1200MPa Grade Ultra-High Strength Gas-Shielded Solid Welding Wire and Its Production Process," describes a welding wire that uses an optimized alloy ratio of low carbon, Si, Mn, Ni, Cr, and Mo to improve weld strength. It incorporates Nb, Ti, and V multi-element microalloying and utilizes solid solution strengthening, grain refinement strengthening, and precipitation strengthening to ensure weld ductility and toughness. During the production of the welding wire through smelting, forging, rolling, drawing, heat treatment, and copper plating processes, vacuum induction and electroslag remelting are used to control the P, S, O, and N contents to below 100ppm. The forged billet has uniform quality, the rolled structure is dense with refined grains, stress is eliminated and the microstructure is improved after annealing, and copper plating provides protection after drawing. The tensile strength of the weld metal is ≥1200MPa, but its impact toughness at -40℃ is ≥27J, indicating relatively low impact energy, which cannot meet market demands. Summary of the Invention

[0004] To overcome the shortcomings of the existing technology, the present invention provides an ultra-high strength gas-shielded welding wire with a weld metal tensile strength of not less than 1200MPa and an impact energy of not less than 47J at -40℃. It can be applied to welding scenarios of high-strength welded joints with a tensile strength of more than 1200MPa and is widely applicable to technical fields such as engineering machinery, high-strength marine engineering, and pressure vessels.

[0005] To achieve the above-mentioned objectives, this invention provides an ultra-high strength gas-shielded welding wire, which belongs to the category of metal powder-cored gas-shielded welding wire. The filling rate of the flux core relative to the total mass of the welding wire is 16% to 20%. The flux core is composed of a mixture of powders of two components, A and B, where A is an alloy powder and B is MnO powder.

[0006] The mass percentage of MnO powder relative to the total mass of the welding wire is 0.01%–0.04%; the mass percentage of alloy A powder relative to the total mass of the welding wire is: C: 0.04%–0.08%, Si: 0.2%–0.5%, Mn: 2.0%–3.0%, Ni: 2.5%–3.5%, Cr: 0.1%–0.3%, Mo: 0.6%–1.0%, Ti: 0.01%–0.04%, B: 0.002%–0.004%, S: 0.002%–0.005%, P: 0–0.01%; the balance is Fe and unavoidable impurities.

[0007] The principle behind the composition design of the aforementioned ultra-high strength gas-shielded welding wire is as follows:

[0008] C: In the weld, C forms interstitial solid solutions or exists in the form of carbides. The C content has a significant impact on the strength, toughness, and microstructure of the weld; its strengthening effect is obvious, significantly improving weld strength. However, it greatly reduces impact toughness and increases the ductile-brittle transition temperature, thus greatly reducing weld toughness. Therefore, based on the performance requirements of the welding wire, the C content is determined to be 0.04%–0.08%.

[0009] Si has the function of deoxidation and strengthening the strength of the weld matrix. It can improve the hardenability of weld metal, but excessive Si content can easily form primary ferrite, which is not conducive to improving the toughness of ultra-high strength welds.

[0010] Mn is an effective element for strengthening and toughening welds. In welds, it facilitates deoxidation and prevents the formation of iron sulfides that cause hot cracking. It also stabilizes austenite, improves the hardenability of the weld metal, and thus enhances the phase transformation strengthening effect. Furthermore, it can increase the strength of steel and weaken or eliminate the adverse effects of sulfur.

[0011] Ni (Ni) is a commonly used element for achieving excellent low-temperature toughness. It can improve hardenability, promote the formation of acicular ferrite, enhance the strength and toughness of welds, especially their impact toughness at medium and low temperatures, and lower the ductile-brittle transition temperature. Furthermore, Ni can stabilize austenite, thereby improving the phase transformation strengthening effect.

[0012] Cr: It helps to reduce proeutectoid ferrite, refine grains, and can also form dispersed carbides with carbon, thereby improving weld strength and toughness.

[0013] Mo is a key element for obtaining high-strength weld metal. As a high-melting-point substance, it has a good grain-refining effect and improves strength with minimal damage to ductility and toughness. It can significantly improve the hardenability of steel and prevent temper brittleness.

[0014] Ti is a microalloying strengthening element. Ti has a strong affinity for C and N, easily forming precipitates that act as nucleation sites and grain boundary pinning sites, thus refining the grain structure of steel and improving the strength and toughness of welds. Ti also has a strong affinity for S, achieving the purpose of spheroidizing non-metallic inclusions and improving performance inhomogeneity.

[0015] B: The combined addition of Ti and B to the weld can better exert the metallurgical effect of B. The presence of appropriate amounts of Ti and B in the weld can effectively suppress and expand the temperature range of acicular ferrite transformation, thereby obtaining a large amount of acicular ferrite in the weld and greatly improving the strength and toughness matching of the weld metal.

[0016] MnO: Adding a certain amount of powdered manganese oxide to metal powder-cored gas-shielded welding wire can improve the purity of the weld, reduce the loss of alloying elements, improve the low-temperature toughness of the weld metal, improve weld formation, and reduce welding spatter.

[0017] S and P are harmful elements, and their content must be controlled to improve weld purity and welding performance. S and P are highly prone to segregation; they easily form non-metallic inclusions and second-phase particles between grains. The presence of a certain amount of S helps to improve weld bead formation and welding wire processability; therefore, welding wire contains 0.002% to 0.005% S and 0 to 0.01% P.

[0018] In the above technical solution, furthermore, the filler content of the flux core relative to the total mass of the welding wire is 17% to 19%; relative to the total mass of the welding wire, the mass percentages of each component of the flux core are: C: 0.045% to 0.075%, Si: 0.25% to 0.45%, Mn: 2.1% to 2.8%, Ni: 2.6% to 3.4%, Cr: 0.15% to 0.3%, Mo: 0.65% to 1.0%, Ti: 0.015% to 0.04%, B: 0.0025% to 0.004%, MnO: 0.015% to 0.04%, S: 0.0025% to 0.005%, P: 0 to 0.01%; the balance is Fe and unavoidable impurities.

[0019] Furthermore, relative to the total mass of the welding wire, the mass percentages of each component in the flux core are as follows: C: 0.05%–0.07%, Si: 0.3%–0.4%, Mn: 2.2%–2.6%, Ni: 2.7%–3.3%, Cr: 0.2%–0.3%, Mo: 0.7%–0.9%, Ti: 0.02%–0.035%, B: 0.003%–0.004%, MnO: 0.02%–0.04%, S: 0.003%–0.0045%, P: 0–0.01%; the balance being Fe and unavoidable impurities.

[0020] Furthermore, relative to the total mass of the welding wire, the mass percentages of each component in the flux core are as follows: C: 0.06%–0.065%, Si: 0.35%–0.4%, Mn: 2.3%–2.5%, Ni: 2.8%–3.2%, Cr: 0.25%–0.3%, Mo: 0.75%–0.8%, Ti: 0.025%–0.03%, B: 0.0035%–0.004%, MnO: 0.03%–0.04%, S: 0.0035%–0.004%, P: 0–0.01%; the balance being Fe and unavoidable impurities.

[0021] Furthermore, the tensile strength of the weld metal deposited by the welding wire is not less than 1200 MPa, and the impact energy at -40℃ is not less than 47 J.

[0022] The above-mentioned metal powder-cored gas shielded welding wire adopts the conventional method for preparing flux-cored welding wire. The steel strip is rolled into a U-shaped tube, and then the flux powder is added into the U-shaped tube. Then, the wire is joined, drawn to reduce the diameter, wound, surface treated, and layered to obtain a metal powder-cored gas shielded welding wire with a diameter of 1.2 to 1.8 mm.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] This invention employs a low-Si, high-Mn, and high-Ni alloy composition, and adds an appropriate amount of powdered MnO, resulting in an ultra-high strength gas-shielded welding wire with excellent processability. The tensile strength is not less than 1200MPa, and the impact energy at -40℃ is not less than 47J; it can well meet the welding requirements of ultra-high strength steel plates. Detailed Implementation

[0025] The present invention will be further described below with reference to specific embodiments, but this does not limit the invention in any way. To avoid redundancy, unless otherwise specified, the raw materials used in the following embodiments are all commercially available products, and the methods used are all conventional methods unless otherwise specified.

[0026] An ultra-high strength gas-shielded welding wire, belonging to the metal powder type flux-cored gas-shielded welding wire, has a flux filling rate of 16% to 20% relative to the total mass of the welding wire; the flux is composed of two powders, A and B, where A is alloy powder and B is MnO powder.

[0027] The mass percentage of MnO powder relative to the total mass of the welding wire is 0.01%–0.04%; the mass percentage of alloy A powder relative to the total mass of the welding wire is: C: 0.04%–0.08%, Si: 0.2%–0.5%, Mn: 2.0%–3.0%, Ni: 2.5%–3.5%, Cr: 0.1%–0.3%, Mo: 0.6%–1.0%, Ti: 0.01%–0.04%, B: 0.002%–0.004%, S: 0.002%–0.005%, P: 0–0.01%; the balance is Fe and unavoidable impurities.

[0028] Any aspects not described in the following embodiments are the same as those described in the specific embodiments above.

[0029] Example

[0030] A high-strength gas-shielded welding wire is described. Table 1 shows the specific components of Examples 1-4. The aforementioned metal powder-cored gas-shielded welding wire is prepared using conventional flux-cored welding wire methods. Steel strip is rolled into a U-shaped tube, flux powder is added to the U-shaped tube, and then the tube is joined, drawn to reduce diameter, wound, surface-treated, and layered to obtain a metal powder-cored gas-shielded welding wire with a diameter of 1.2–1.8 mm. Welding tests were conducted using 80% Ar + 20% CO2 shielding, with a welding current of 280A–320A, a welding voltage of 28V–32V, and a welding speed of 6 mm / s. Table 2 shows the mechanical properties of the deposited metal in each example.

[0031] Table 1. Composition of Ultra-High Strength Gas-Shielded Welding Wire in Examples

[0032] Example 1 0.04 0.2 2.1 3.0 0.1 0.7 0.04 0.002 0.01 0.002 0.006 Example 2 0.06 0.3 2.5 2.6 0.1 0.7 0.03 0.002 0.02 0.003 0.008 Example 3 0.05 0.4 2.8 3.3 0.2 0.9 0.02 0.003 0.03 0.004 0.006 Example 4 0.08 0.5 2.9 2.8 0.3 0.9 0.02 0.003 0.04 0.003 0.008

[0033] Table 2. Deposited metal properties of welding wires in the examples.

[0034]

[0035] As shown in Table 2, the technical solution of this invention can make the tensile strength of the weld metal not less than 1200MPa, the impact toughness of the weld at -40℃ not less than 47J, and the strength and toughness of the weld metal are well matched.

[0036] For anyone skilled in the art, many possible variations and modifications can be made to the technical solutions of this invention, or equivalent embodiments can be modified based on the disclosed technical content, without departing from the scope of the technical solutions of this invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this invention without departing from the content of the technical solutions of this invention should still fall within the protection scope of the technical solutions of this invention.

Claims

1. An ultra-high strength gas shielded welding wire, characterized by, The flux core has a filling rate of 16% to 20% relative to the total mass of the welding wire; the flux core is composed of two powders, A and B, where A is alloy powder and B is MnO powder. Relative to the total mass of the welding wire, the mass percentage of MnO powder is 0.01%~0.02%; the mass percentage of alloy A powder components is: C: 0.04%~0.08%, Si: 0.2%~0.5%, Mn: 2.0%~3.0%, Ni: 2.6%~3.0%, Cr: 0.1%~0.3%, Mo: 0.6%~1.0%, Ti: 0.01%~0.04%, B: 0.002%~0.004%, S: 0.002%~0.005%, P: 0~0.01%; the balance is Fe and unavoidable impurities. The tensile strength of the weld metal deposited by the welding wire shall not be less than 1200 MPa, and the impact energy at -40℃ shall not be less than 47 J. The diameter of ultra-high strength gas-shielded welding wire is 1.2 to 1.8 mm.

2. The UHSS gas shielded welding wire of claim 1, wherein, The flux-cored filler content relative to the total mass of the welding wire is 17% to 19%.

3. A method for preparing the ultra-high strength gas-shielded welding wire as described in any one of claims 1-2, characterized in that, The steel strip is rolled into a U-shaped tube, and then the flux powder is added into the U-shaped tube. Then the tube is joined, drawn to reduce the diameter, wound up, surface treated, and layered to produce a metal powder-cored gas shielded welding wire with a diameter of 1.2~1.8 mm.

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