Ultrahigh-strength gas shielded welding wire

Abstract

According to the ultrahigh-strength gas shielded welding wire, the filling rate of a flux core in the welding wire ranges from 16% to 20%, the flux core is formed by mixing powder of a component A and powder of a component B, the component A is alloy powder, and the component B is MnO powder; relative to the total mass of the welding wire, the mass percent of the MnO powder is 0.01%-0.04%, and the alloy powder A comprises the following components in percentage by mass: 0.04%-0.08% of C, 0.2%-0.5% of Si, 2.0%-3.0% of Mn, 2.5%-3.5% of Ni, 0.1%-0.3% of Cr, 0.6%-1.0% of Mo, 0.01%-0.04% of Ti, 0.002%-0.004% of B, 0.002%-0.005% of S and the like. According to the welding wire, low-silicon, high-Mn and high-Ni alloy matching is adopted, MnO powder is added, the tensile strength of deposited metal is not lower than 1200 MPa, and the impact energy at the temperature of-40 DEG C is not lower than 47 J.

Description

Technical Field

[0001] The invention belongs to the technical field of welding materials, and in particular relates to an ultra-high strength gas shielded welding wire. Background Art

[0002] In recent years, with the rise of large-scale projects in various fields in my country, construction machinery and equipment have gradually developed in the direction of "high-end, high-tech content, high added value and large tonnage". In order to improve the performance of mechanical equipment to meet the needs of various engineering construction to the greatest extent, while requiring the reduction of its own weight, energy consumption and cost, the strength level of steel used in construction machinery has been continuously improved, and the demand for high-strength and high-toughness welding materials has also been increasing.

[0003] At present, domestic steel mills have successfully developed high-strength steel varieties with tensile strengths above 1200MPa and widely used them in related welding structures, but the research and development of welding materials is relatively lagging and it is difficult to meet market demand. For example, the patent "A low-cost ultra-high-strength steel laser welding wire" with publication number CN114769939B achieves a joint strength of more than 800MPa after hot-formed cold-rolled plate welding, but it is only suitable for laser welding. The welding wire disclosed in the patent "A gas shielded welding wire and weld metal for ultra-high strength steel" with publication number CN 104785955 A contains, 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, and the remainder is Fe and impurity elements; through mixed gas shielded welding, a weld metal with a tensile strength ≥1000MPa and a yield strength ≥850MPa can be obtained; but its strength does not reach 1200MPa. Patent CN115673601A "A 1200MPa grade ultra-high strength gas shielded solid welding wire and its production process" uses an optimized alloy ratio of low carbon, Si, Mn, Ni, Cr, and Mo to improve the strength of the weld, combined with Nb, Ti, and V multi-element micro-alloying, and uses solid solution strengthening, fine grain strengthening, and precipitation strengthening to ensure the plastic toughness of the weld; when producing 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 be below 100ppm, the forging billet has uniform quality, the rolling structure is dense, the grains are refined, the stress is eliminated and the structure is improved after annealing, and copper plating protection is applied after drawing; the tensile strength of the deposited metal of the welding wire is ≥1200MPa, but its -40℃ impact toughness is ≥27J, and the impact energy is relatively low, which cannot meet market demand. Summary of the invention

[0004] In order to overcome the defects of the above-mentioned prior art, the present invention provides an ultra-high strength gas shielded welding wire, the tensile strength of the deposited metal of the welding wire is not less than 1200MPa, and the impact energy at -40℃ is not less than 47J; it can be used in welding scenarios of high-strength welding joints with a tensile strength of more than 1200MPa, and is widely used in technical fields such as engineering machinery, high-strength marine engineering, and pressure vessels.

[0005] In order to achieve the above-mentioned invention object, the present invention provides an ultra-high strength gas shielded welding wire, which belongs to a metal powder type flux-cored gas shielded welding wire, and the filling rate of the flux core relative to the total mass of the welding wire is 16% to 20%; the flux core is made of a mixture of powders of two components A+B, A is an alloy powder, and B is MnO powder;

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

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

[0008] C: It will form interstitial solid solution or exist in the weld in the form of carbide; the C content has a great influence on the strength and toughness of the weld and its organizational composition. Its strengthening effect is very obvious and can significantly improve the strength of the weld; but it will greatly reduce the impact toughness and increase the toughness-brittle transition temperature, thereby greatly reducing the toughness of the weld. Therefore, according to the performance requirements of the welding wire, the C content is determined to be 0.04% to 0.08%.

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

[0010] Mn: It is an effective element for strengthening and toughening the weld. It is beneficial for deoxidation in the weld and prevents the formation of iron sulfides that cause hot cracks. It has the function of stabilizing austenite, improving the hardenability of the weld metal, and thus improving the effect of phase transformation strengthening. It can improve the strength of steel and weaken or eliminate the adverse effects of sulfur.

[0011] Ni: It is a commonly used element to obtain excellent low-temperature toughness. It can improve hardenability, promote the formation of acicular ferrite, improve the strength and toughness of the weld, especially the medium and low temperature impact toughness, and reduce the tough-to-brittle transition temperature. Ni can also stabilize austenite, thereby improving the effect of phase transformation strengthening.

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

[0013] Mo: It is the main element for obtaining high-strength weld metal. As a high-melting-point substance, it has a good grain refinement effect and does not significantly damage plasticity and toughness while increasing strength. It can significantly improve the hardenability of steel and prevent temper brittleness.

[0014] Ti: It is a microalloy strengthening element; Ti has a strong affinity with C and N, and is easy to form a precipitate phase and become a nucleation point and a pinning point at the grain boundary to achieve the effect of refining the grain structure of the steel, thereby improving the strength and toughness of the weld. Ti also has a strong affinity with S, achieving the purpose of spheroidizing non-metallic inclusions and improving uneven performance.

[0015] B: The combined addition of Ti and B in the weld can better exert the metallurgical effect of B. The appropriate amount of Ti and B in the weld can effectively inhibit and expand the temperature range of acicular ferrite transformation, and thus a large amount of acicular ferrite can be obtained in the weld, greatly improving the strength and toughness matching of the weld metal.

[0016] MnO: Adding a certain amount of powdered manganese oxide to metal powder-type flux-cored gas shielded welding wire can improve the purity of the weld, reduce the burn-off of alloy elements, increase the low-temperature toughness of the weld metal, improve weld formation, reduce welding spatter, etc.

[0017] S and P are harmful elements. Their contents are controlled to improve the purity and welding performance of the weld. S and P are very easy to segregate; they are easy to form non-metallic inclusions and second phase particles between grains. A certain amount of S helps to improve the weld bead forming and the processability of the welding wire. Therefore, the welding wire contains 0.002% to 0.005% S and 0 to 0.01% P.

[0018] In the above technical scheme, further, the filling rate 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 percentage of each component of the flux core is 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 the components of the flux core are 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 remainder is Fe and unavoidable impurities.

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

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

[0022] The above-mentioned metal powder type flux-cored gas shielded welding wire adopts the conventional flux-cored welding wire preparation method, rolling the steel strip into a U-shaped tube, adding the powder into the U-shaped tube, and then closing the seam, drawing and reducing the diameter, winding the wire, surface treatment, and layer winding to obtain a metal powder type flux-cored gas shielded welding wire with a diameter of 1.2 to 1.8 mm.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention adopts low Si, high Mn, high Ni alloy matching, and adds a proper amount of powdered MnO to obtain an ultra-high strength gas shielded welding wire with good processability, a tensile strength of not less than 1200MPa, and an impact energy of not less than 47J at -40°C; and can well meet the welding requirements of ultra-high strength steel plates. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with specific examples, but the present invention is not limited in any way. To avoid redundant description, the raw materials in the following examples are all commercially available products unless otherwise specified, and the methods used are all conventional methods unless otherwise specified.

[0026] An ultra-high strength gas shielded welding wire, belonging to a metal powder type flux 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 made of a mixture of powders of two components A+B, A is an alloy powder, and B is MnO powder;

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

[0028] The matters not described in the following embodiments are the same as the description of the above specific implementation methods.

[0029] Example

[0030] An ultra-high strength gas shielded welding wire, Table 1 shows the specific components of Examples 1-4, the above metal powder type flux cored gas shielded welding wire adopts a conventional flux cored welding wire preparation method, the steel strip is rolled into a U-shaped tube, and then the powder is added to the U-shaped tube, and then the seam is closed, the wire is drawn and reduced, the wire is taken up, the surface is treated, and the layer is wound to obtain a metal powder type flux cored gas shielded welding wire with a diameter of 1.2-1.8 mm. The welding test adopts 80% Ar + 20% CO2 for protection, the welding current is 280A-320A, the welding voltage is 28V-32V, and the welding speed is 6mm / s. Table 2 shows the mechanical properties of the deposited metal of each embodiment.

[0031] Table 1 Composition of ultra-high strength gas shielded welding wire in the embodiment

[0032] C Si Mn Ni Cr Mo Ti B MnO S P 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 wire welding test in Example

[0034]

[0035] It can be seen from the data in Table 2 that the technical solution of the present invention can make the tensile strength of the deposited metal not less than 1200MPa, the impact toughness of the -40℃ weld not less than 47J, and the strength and toughness of the deposited metal of the welding wire are well matched.

[0036] For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should still fall within the scope of protection of the technical solution of the present invention.

Claims

1. An ultra-high strength gas shielded welding wire, characterized in that: The filling rate of the flux core relative to the total mass of the welding wire is 16% to 20%; the flux core is a mixture of two powder components A+B, A is an 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% to 0.04%; the mass percentages of the components of the A alloy powder are C: 0.04% to 0.08%, Si: 0.2% to 0.5%, Mn: 2.0% to 3.0%, Ni: 2.5% to 3.5%, Cr: 0.1% to 0.3%, Mo: 0.6% to 1.0%, Ti: 0.01% to 0.04%, B: 0.002% to 0.004%, S: 0.002% to 0.005%, P: 0 to 0.01%; the remainder is Fe and unavoidable impurities.

2. The ultra-high strength gas shielded welding wire according to claim 1, characterized in that: The filling rate 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 percentage of each component of the flux core is 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%~0.04%, S: 0.0025%~0.005%, P: 0~0.01%; the balance is Fe and unavoidable impurities.

3. The ultra-high strength gas shielded welding wire according to claim 1, characterized in that: Relative to the total mass of the welding wire, the mass percentage of each component of the flux core is 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 is Fe and unavoidable impurities.

4. The ultra-high strength gas shielded welding wire according to claim 1, characterized in that: Relative to the total mass of the welding wire, the mass percentage of each component of the flux core is 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 is Fe and unavoidable impurities.

5. The ultra-high strength gas shielded welding wire according to claim 1, characterized in that: The deposited metal tensile strength of the welding wire is not less than 1200MPa, and the impact energy at -40°C is not less than 47J.

6. A method for preparing the ultra-high strength gas shielded welding wire according to any one of claims 1 to 5, characterized in that: The steel strip is rolled into a U-shaped tube, and then powder is added into the U-shaped tube, followed by seaming, wire drawing and reducing the diameter, wire winding, surface treatment, and layer winding to obtain a metal powder type flux-cored gas shielded welding wire with a diameter of 1.2 to 1.8 mm.

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