A 590mpa grade solid wire, laser-arc hybrid welding process and welded joint

Abstract

This invention provides a 590MPa grade solid welding wire, a laser-arc hybrid welding process, and a welded joint. The composition system of this invention is precisely adapted to the rapid heating and cooling thermal cycle characteristics and the burn-off law of key alloying elements in laser-arc hybrid welding of 590MPa grade marine engineering steel. By strictly controlling the content of highly hardenable elements such as C, Mn, Ni, and Mo, the formation of hardened structures in the weld metal is avoided. A certain amount of Ti element is added to provide nucleation points within the grains, directionally inducing the formation of a highly oriented and complex acicular ferrite matrix structure, thereby simultaneously improving strength and toughness through grain refinement. At the same time, an appropriate amount of V element is added to further improve the strength margin of the weld metal through microalloying. This welding wire has excellent welding processability and crack resistance, and can achieve room temperature welding without preheating or post-heating, providing material support for the high-quality and high-efficiency construction of marine engineering equipment.

Description

Technical Field

[0001] This invention relates to the field of welding materials technology, and more specifically, to a 590MPa grade solid welding wire, a laser-arc hybrid welding process, and a welded joint. Background Technology

[0002] Laser-arc hybrid welding is a core technology for the efficient construction of high-end marine engineering equipment. 590MPa grade marine steel, as a core high-strength load-bearing steel, places stringent requirements on weld strength, -50℃ low-temperature toughness, and thick-plate adaptability. However, the rapid heating and cooling thermal cycling characteristics of hybrid welding cause the weld to easily form hardened structures such as granular bainite and lath bainite when directly welded using conventional gas-shielded welding wire. The impact absorption energy at -50℃ drops drastically from 120-136J to 32-57J, failing to meet the requirements for high load-bearing capacity and low-temperature service. The Norwegian shipyard Kleven used equal-strength gas-shielded welding wire to complete laser-arc hybrid welding of 420MPa grade marine high-strength steel. Mechanical property testing showed that the impact absorption energy at -30℃ decreased from 210-240J to 20-40J, while the crack opening displacement decreased to 0.13-0.19mm, resulting in a significant reduction in overall performance.

[0003] Existing technologies are completely inadequate for the 590MPa level requirement. Patent CN113441871A discloses a flux-cored welding wire suitable for laser-arc hybrid welding, with a weld metal yield strength of 420-460MPa. However, its impact absorption energy at -20℃ is only about 50J, which is insufficient to meet the performance requirements of my country's marine engineering equipment for this strength level of welding wire. Furthermore, the welding material in this invention is flux-cored welding wire, which is more expensive than solid welding wire. Due to its softness, flux-cored welding wire is difficult to meet the high-speed and stable wire feeding requirements of laser-arc hybrid welding. In addition, flux-cored welding wire has high requirements for storage environment and poor adaptability to practical engineering applications.

[0004] Patent CN113001059A discloses a 440MPa grade high-strength steel welding wire and a laser-arc hybrid welding process. The welding wire requires the use of a material containing… The use of mixed gas for protection increases the cost of engineering applications. Furthermore, the welding wire contains Cr and Cu elements, resulting in a complex alloy system and high element content, making batch stability control difficult. In addition, the strength is insufficient and cannot meet the high strength and toughness matching requirements of 590MPa grade composite weld metal.

[0005] Currently, there is a lack of solid welding wire specifically designed for laser-arc hybrid welding of 590MPa grade marine steel. The efficient welding of high-end marine engineering equipment is limited by the lack of welding materials. There is an urgent need to develop a dedicated solid welding wire that meets the unique metallurgical characteristics of laser-arc hybrid welding and has excellent strength and toughness matching and good adaptability. Summary of the Invention

[0006] In view of this, the present invention aims to propose a 590MPa grade solid welding wire, a laser-arc hybrid welding process, and a welded joint to solve the problem that the lack of a dedicated high-performance solid welding wire suitable for laser-arc hybrid welding of 590MPa grade marine engineering steel in the prior art leads to poor strength and toughness matching of the weld metal, which cannot meet the high-efficiency and high-quality welding requirements of marine engineering equipment.

[0007] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0008] A 590MPa grade solid welding wire, wherein the chemical composition of the welding wire, by mass percentage, is: C: 0.02-0.05%, Si: 0.20-0.40%, Mn: 0.9-1.3%, Ni: 2.1-2.6%, Cr: ≤0.3%, Mo: 0.28-0.6%, V: 0.03-0.06%, Ti: ≤0.05%, S≤0.010%, P≤0.015%, with the balance being Fe and unavoidable impurities.

[0009] The composition system of this invention is precisely adapted to the rapid heating and cooling thermal cycling characteristics and the burn-off patterns of key alloying elements in laser-arc hybrid welding of 590MPa grade marine engineering steel. By strictly controlling the content of highly hardenable elements such as C, Mn, Ni, and Mo, the formation of hardened structures in the weld metal is avoided. A certain amount of Ti is added to provide nucleation sites within the grains, directionally inducing the formation of a highly oriented and complex acicular ferrite matrix, thereby simultaneously improving strength and toughness through grain refinement. Simultaneously, an appropriate amount of V is added to further enhance the strength margin of the weld metal through microalloying. This welding wire exhibits excellent weldability and crack resistance, enabling room temperature welding without preheating or post-heating, providing material support for the high-quality and efficient construction of marine engineering equipment.

[0010] In some embodiments, the chemical composition of the welding wire, by mass percentage, is: C: 0.036%, Si: 0.308%, Mn: 1.09%, Ni: 2.57%, Mo: 0.626%, V: 0.051%, Ti: 0.027%, S: 0.0032%, P: 0.0087%, with the remainder being Fe and unavoidable impurities.

[0011] This formulation utilizes the synergistic effect of high Ni content (2.57%) and moderate Mo content (0.626%) in the alloy system to greatly improve the low-temperature toughness of the microstructure while ensuring strength. Furthermore, the C content is controlled at 0.036%, which effectively avoids cold cracking sensitivity and achieves a balance in overall mechanical properties.

[0012] In some embodiments, the chemical composition of the welding wire, by mass percentage, is: C: 0.047%, Si: 0.319%, Mn: 1.06%, Ni: 2.48%, Cr: 0.206%, Mo: 0.607%, V: 0.051%, Ti: 0.031%, S: 0.0030%, P: 0.010%, with the remainder being Fe and unavoidable impurities.

[0013] This formulation introduces a trace amount of Cr (0.206%), which ensures good hardenability of the welding wire without significantly increasing crack susceptibility. The deposited metal yield strength of this formulation reaches 704 MPa, and the impact absorption energy at -50℃ remains at a high level of 130 J. The welded joint exhibits excellent uniformity of mechanical properties, balancing strength, toughness, and process adaptability.

[0014] In some embodiments, the chemical composition of the welding wire, by mass percentage, is: C: 0.035%, Si: 0.309%, Mn: 1.33%, Ni: 2.49%, Mo: 0.612%, V: 0.051%, Ti: 0.027%, S: 0.0030%, P: 0.0092%, with the remainder being Fe and unavoidable impurities.

[0015] This formulation appropriately increases the Mn content (1.33%), utilizing its solid solution strengthening effect to further enhance strength. Simultaneously, the composite precipitation strengthening of Mo (0.612%) and V (0.051%) compensates for the potential strength loss due to the low C content (0.035%). This formulation achieves a good match between a yield strength of 691 MPa and an impact energy of 122 J at -50℃, demonstrating the flexibility of the composition design.

[0016] In some embodiments, the chemical composition of the welding wire, by mass percentage, is: C: 0.029%, Si: 0.310%, Mn: 0.92%, Ni: 2.13%, Mo: 0.28%, V: 0.031%, Ti: 0.025%, S: 0.0046%, P: 0.0061%, with the remainder being Fe and unavoidable impurities.

[0017] This formulation demonstrates the feasibility of implementing the present invention at a relatively low alloy cost. By reducing the content of elements such as C, Mn, Ni, and Mo, and adding an appropriate amount of V (0.031%) for microalloying, it is still possible to ensure that the yield strength of the weld metal reaches the minimum standard requirement of 593 MPa. Furthermore, due to the low total alloy content, the weld metal exhibits excellent plasticity and toughness (impact energy up to 146 J at -50℃), making it particularly suitable for engineering scenarios where cost control of welding materials is required.

[0018] In some embodiments, the yield strength of the weld metal of the welding wire Impact absorption energy of 593–704 MPa at -50°C The J ranges from 122 to 146.

[0019] These mechanical performance indicators can precisely match the strength service requirements of 590MPa-class marine engineering structures. The energy absorbed by the -50℃ low-temperature impact far exceeds the industry standard, which can ensure the service safety of marine engineering equipment under complex working conditions of low temperature and high load. It achieves a synergistic improvement in strength and toughness, without the problems of excessive strength or insufficient toughness reserves.

[0020] A laser-arc hybrid welding process is described above, using the aforementioned 590MPa grade solid welding wire. The welding process parameters are as follows: laser power 1.0~10.0kW, defocusing amount -2~+2mm, wire spacing 2~5mm, wire feed speed 7~12m / min, welding speed 50~200cm / min, and shielding gas flow rate 15~25L / min.

[0021] The process parameters are highly compatible with the aforementioned welding wire composition, which is in line with the characteristics of concentrated heat source density and fast welding speed in laser-arc hybrid welding. This ensures smooth droplet transfer and regular weld formation, while precisely controlling the phase transformation of the weld metal structure, thus achieving efficient, low-stress, and defect-free laser-arc hybrid welding of typical specification test plates.

[0022] In some embodiments, adopt The mixed gas is used as a welding shielding gas.

[0023] Using argon-rich gas (95% Ar) as the main shielding gas helps maintain arc stability, reduce spatter, and improve weld formation; adding a small amount (5%) This helps improve arc stability and molten pool fluidity, effectively suppressing welding defects.

[0024] A welded joint is formed by welding using the aforementioned laser-arc hybrid welding process.

[0025] In some embodiments, the weld metal microstructure of the welded joint is mainly composed of acicular ferrite. At -50°C, the impact specimen size is 5×10×55mm, corresponding to the impact absorption energy of the weld metal. The impact energy is 87–96 J, and the dimensions of the impact specimen are 10 × 10 × 55 mm. This corresponds to the impact absorbed energy of the weld metal. The value is 122–141 J.

[0026] The weld metal, with its predominantly acicular ferrite microstructure, can effectively deflect crack propagation paths and hinder crack extension. Its -50℃ impact absorption energy covers the full range of working conditions for thick / thin plate joints. It has ample low-temperature toughness reserves and excellent crack resistance, making it well-suited for the harsh low-temperature service environment of marine engineering equipment and ensuring the safety and stability of the structure.

[0027] Compared with existing technologies, the 590MPa grade solid welding wire, laser-arc hybrid welding process, and welded joint described in this invention have the following advantages:

[0028] 1) The yield strength of the weld metal is 593~704MPa, and the impact absorption energy at -50℃ is 122~146J. The impact absorption energy of a typical welded joint at -50℃ is... The impact strength is 87-96J (impact sample size: 5×10×55mm); 122-141J (impact sample size: 10×10×55mm), suitable for 6mm / 35mm plates;

[0029] 2) It can effectively suppress the formation of hardened structures, form a matrix structure of acicular ferrite with high orientation complexity, and a high proportion of large-angle grain boundaries, thereby improving the crack resistance and structural stability of thick plate joints.

[0030] 3) It achieves room temperature welding without preheating or postheating, and without defects. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the double Y-shaped bevel as described in an embodiment of the present invention;

[0032] Figure 2 This is a typical metallographic morphology diagram of the weld metal described in Embodiment 1 of the present invention;

[0033] Figure 3 This is the crystallographic orientation diagram of the weld metal described in Embodiment 1 of the present invention;

[0034] Figure 4 This is a low-magnification topographic image of the front side of the laser-arc hybrid weld seam described in Embodiment 1 of the present invention;

[0035] Figure 5 This is a low-magnification topography image of the back side of the laser-arc hybrid weld seam described in Embodiment 1 of the present invention;

[0036] Figure 6 This is a low-magnification cross-sectional topography of the laser-arc hybrid welding head described in Embodiment 1 of the present invention. Detailed Implementation

[0037] The following describes in detail the 590MPa high-strength and tough solid welding wire and the laser-arc composite welding process provided by the present invention, with reference to the embodiments and accompanying drawings.

[0038] This invention is based on the composition system of 590MPa marine engineering steel, combined with the rapid heating and cooling thermal cycle characteristics of laser-arc composite welding and the burning loss law of alloy elements. With the core design principle of improving the orientation complexity of weld metal structure, it carries out precise design of welding wire composition.

[0039] By measuring the thermal cycle curve of laser-arc hybrid welded seam of 590MPa grade marine engineering steel and comparing it with the thermal cycle of conventional gas shielded welding, the metallurgical behavior characteristics of hybrid welding were clarified. The burn-off mechanism of key elements such as C, Si, Mn and Ni in laser-arc hybrid welding process was systematically studied, and an alloy composition control system was constructed on this basis.

[0040] Based on the understanding of the microstructure characteristics of weld metal at this strength level, acicular ferrite is used as the matrix microstructure of weld metal. The content of highly hardenable elements such as C and Mn is strictly controlled to suppress the formation of bainite under rapid cooling conditions, thus avoiding excessive strength and insufficient toughness reserves. At the same time, the content of Ni and Mo elements is synergistically regulated and a certain amount of Ti element is added to provide nucleation particles, inducing the formation of highly oriented and complex acicular ferrite in weld metal, suppressing the formation of side strip ferrite and granular bainite, thereby achieving a synergistic improvement in the strength and toughness of weld metal.

[0041] This invention provides a 590MPa grade solid welding wire, the chemical composition of which, by mass percentage, is: C: 0.02-0.05%, Si: 0.20-0.40%, Mn: 0.9-1.3%, Ni: 2.1-2.6%, Cr: ≤0.3%, Mo: 0.3-0.6%, V: 0.03-0.06%, Ti: ≤0.05%, S≤0.010%, P≤0.010%, with the remainder being Fe and unavoidable impurities.

[0042] The alloying elements in the welding wire were designed with different contents based on the analysis of their functions. The final composition of the welding wire was determined only after a long period of extensive trial production.

[0043] Carbon (C), as an interstitial solid solution strengthening element, can significantly improve strength. However, excessive C can easily lead to lattice distortion, stress concentration, crack induction, and deterioration of toughness. Under rapid cooling conditions in composite welding, high C content can promote lath bainite formation and reduce low-temperature toughness. Therefore, the C content is limited to 0.02–0.05% to balance strengthening effect and toughness assurance.

[0044] Si can combine with O to form SiO2, thus playing a role in deoxidation and improving the wettability of the molten metal droplet. This has an important impact on the weld formation when carrying out high-speed laser-arc hybrid welding. However, the Si content in the deposited metal should not be too high to avoid increasing the crack sensitivity of the deposited metal. Therefore, the Si content is controlled between 0.20% and 0.40%.

[0045] Manganese (Mn) can effectively strengthen metals through solid solution; theoretically, an increase of 0.1% in Mn content can increase the yield strength by 20–30 MPa. It also acts as a deoxidizer during welding, combining with oxygen to form MnO. However, excessive Mn content will reduce weldability and toughness; the Mn content should be controlled between 0.9% and 1.3%.

[0046] Ni is a typical element that expands the austenite phase region. It is generally believed that Ni can improve the low-temperature toughness of steel materials by increasing the content of retained austenite or reducing the resistance to dislocation movement. Taking into account both the alloy system compatibility and the requirements for phase transformation control, the Ni content is controlled at 2.1% to 2.6%.

[0047] Cr can effectively improve the hardenability of weld metal and enhance its strength through solid solution strengthening. However, in laser-arc hybrid welding, excessive Cr content can lead to a greater tendency for hardening of the weld metal, resulting in reduced low-temperature toughness. Considering the combined effects of Cr on the strength and toughness of weld metal, the Cr content should be controlled below 0.3%.

[0048] Mo is an element that has a significant impact on the bainitic transformation point. At the same time, Mo is a strong carbide-forming element. Under the action of subsequent weld beads, it can combine with C to form M2C type nano-precipitates, which can effectively improve the strength of weld metal through precipitation strengthening. Considering the influence of elements in this alloy system on the hardenability of weld metal, the Mo content is controlled at 0.3-0.6%.

[0049] V is a strong carbide-forming element that tends to form MX-type carbides with C and N, playing a strengthening role in weld metal. V also has a solid solution strengthening effect, which can effectively improve strength. Adding an appropriate amount of V can compensate for the strength loss caused by the reduction of C content. The V content should be controlled between 0.03% and 0.06%.

[0050] Ti readily combines with oxygen in the weld metal to form small oxides, which can provide nucleation sites for bainite laths within the grains, inducing intragranular nucleation and further increasing the complexity of the weld metal's microstructure orientation, the proportion of large-angle grain boundaries, and the microstructure's ability to prevent cracking. However, excessively high Ti content can reduce the weld wire's processability. Based on previous experimental data, the Ti content is controlled below 0.05%.

[0051] S and P are harmful impurity elements that can easily cause hot brittleness and cold brittleness. To balance smelting costs and weld performance, the upper limit for both is controlled at 0.010%.

[0052] The preparation process of the welding wire of this invention is the same as that of the prior art.

[0053] Example 1

[0054] This embodiment provides a 590MPa grade solid welding wire. The chemical composition of the welding wire, by mass percentage, is: C: 0.036%, Si: 0.308%, Mn: 1.09%, Ni: 2.57%, Mo: 0.626%, V: 0.051%, Ti: 0.027%, S: 0.0032%, P: 0.0087%, with the remainder being Fe and unavoidable impurities.

[0055] Preferably, the chemical composition of the welding wire, by mass percentage, is as follows: C: 0.029–0.047%, Si: 0.308–0.319%, Mn: 0.92–1.33%, Ni: 2.13–2.57%, Cr: ≤0.206%, Mo: 0.28–0.626%, V: 0.031–0.051%, Ti: 0.025–0.031%, S ≤0.0046%, P ≤0.010%, with the remainder being Fe and unavoidable impurities.

[0056] The welding wire specification was φ1.2mm. The steel plates used in the test were typical specifications of 6mm and 35mm thick 590MPa grade marine engineering steel. The preparation process of the deposited metal is shown in Table 2, and the laser-arc hybrid welding process of typical specification test plates is shown in Table 3. As a protective gas.

[0057] Example 2

[0058] The difference between this embodiment and Embodiment 1 is that the chemical composition of the welding wire is different. In this embodiment, the chemical composition of the welding wire, by mass percentage, is: C: 0.047%, Si: 0.319%, Mn: 1.06%, Ni: 2.48%, Cr: 0.206%, Mo: 0.607%, V: 0.051%, Ti: 0.031%, S: 0.0030%, P: 0.010%, with the remainder being Fe and unavoidable impurities.

[0059] Example 3

[0060] The difference between this embodiment and Embodiment 2 lies in the chemical composition of the welding wire. In this embodiment, the chemical composition of the welding wire, by mass percentage, is as follows: C: 0.035%, Si: 0.309%, Mn: 1.33%, Ni: 2.49%, Mo: 0.612%, V: 0.051%, Ti: 0.027%, S: 0.0030%, P: 0.0092%, with the remainder being Fe and unavoidable impurities.

[0061] Example 4

[0062] The difference between this embodiment and Embodiment 3 is that the chemical composition of the welding wire is different. In this embodiment, the chemical composition of the welding wire, by mass percentage, is: C: 0.029%, Si: 0.310%, Mn: 0.92%, Ni: 2.13%, Mo: 0.28%, V: 0.031%, Ti: 0.025%, S: 0.0046%, P: 0.0061%, with the remainder being Fe and unavoidable impurities.

[0063] Comparative Example 1

[0064] The difference between this comparative example and Examples 1-4 is that the chemical composition of the welding wire is different. In this comparative example, the chemical composition of the welding wire, by mass percentage, is: C: 0.034%, Si: 0.201%, Mn: 0.798%, Ni: 1.48%, Ti: 0.029%, S: 0.0022%, P: 0.0080%, with the remainder being Fe and unavoidable impurities.

[0065] Comparative Example 2

[0066] The difference between this comparative example and Examples 1-4 is that the chemical composition of the welding wire is different. In this comparative example, the chemical composition of the welding wire, by mass percentage, is: C: 0.042%, Si: 0.502%, Mn: 1.56%, Ni: 2.33%, Mo: 0.732%, V: 0.048%, Ti: 0.022%, S: 0.0025%, P: 0.0081%, with the remainder being Fe and unavoidable impurities.

[0067] Comparative Example 3

[0068] The difference between this comparative example and Examples 1-4 is that the chemical composition of the welding wire is different. In this comparative example, the chemical composition of the welding wire, by mass percentage, is: C: 0.036%, Si: 0.194%, Mn: 0.847%, Ni: 1.24%, V: 0.055%, Ti: 0.019%, S: 0.0026%, P: 0.0084%, with the remainder being Fe and unavoidable impurities.

[0069] Table 1 Chemical composition (wt.%) of welding wire for 590MPa grade composite welding

[0070]

[0071] Table 2. Preparation process of fused metal

[0072]

[0073] Table 3. Specifications for Laser-Arc Hybrid Welding of 6mm Thick Butt Plates

[0074]

[0075] Table 4. Test results of mechanical properties of the deposited metal

[0076]

[0077] Table 5. Test results of mechanical properties of 6mm thick laser-arc hybrid welded butt joints

[0078]

[0079] Note (a): Straight bend, back bend. It won't crack at 120° and won't break at 180°.

[0080] As shown in Tables 4 and 5, the mechanical property test results indicate that Examples 1-4 all have good strength and toughness matching. With the yield strength of the fused metal reaching 590 MPa, the impact absorption energy at -50℃ reaches more than 120 J.

[0081] The yield strength of the weld metal in Comparative Examples 1 and 3 did not reach 590 MPa, failing to meet the structural safety service strength requirements. In Comparative Example 1, the Mn content was only 0.798%, and the Ni content was 1.48%, while Mo and V were not added, resulting in insufficient strengthening of the weld metal. In Comparative Example 3, 0.055% V was added, but the Mn content was only 0.847%, and the Ni content was only 1.24%, while Mo was not added, again resulting in insufficient strengthening. In Comparative Example 2, the Mn and Mo contents were significantly higher than in the examples. Mn and Mo are typical elements that improve hardenability and have good solid solution strengthening effects, resulting in higher weld metal strength in Comparative Example 2, with a yield strength of 731 MPa and a considerable strength margin. However, the impact absorption energy at -50°C decreased to 77 J, far lower than the low-temperature toughness of the weld metal in the examples.

[0082] Meanwhile, laser-arc hybrid welding was performed using 590MPa grade marine steel with a typical specification of 6mm. Through plate tension, bending and weld metal impact tests on the welded joints, it was found that the tensile strength of the welded joints with different alloy compositions of welding wires was above 700MPa, and the fracture location was in the base metal. The weld metal of the four examples could absorb more than 87J of impact energy at -50℃ (impact specimen size: 5×10×55mm), while the weld metal of Comparative Example 2 absorbed only 32J of impact energy (impact specimen size: 5×10×55mm), indicating insufficient low-temperature toughness reserve.

[0083] Table 6 Specifications for Laser-Arc Hybrid Welding of 35mm Thick Butt Test Plates

[0084]

[0085] Table 7. Test results of mechanical properties of 35mm thick laser-arc hybrid welded butt joints

[0086]

[0087] To verify the engineering applicability of the welding wires in Examples 1-4, a typical specification of 35mm thick 590MPa marine engineering steel was used for adaptability verification. The welding wires in Examples 1-4 were used, and the welding parameters are shown in Table 6. The welded joints were constructed using... Figure 1 The mechanical properties of the welded joints with the double Y-groove (H=8mm, θ=60°) shown are illustrated in Table 7. It can be seen that when welding a typical 35mm thick test plate using the welding wires from Examples 1-4, the welded joints exhibit excellent strength-toughness matching, reflecting the good engineering adaptability of this welding wire.

[0088] Since the weld metal microstructure is similar in different embodiments, the weld metal microstructure in Example 1 will be observed here. Figure 2-3 The typical metallographic structure and crystallographic orientation diagram of the weld metal in Example 1 show that the weld metal is composed of a large number of acicular ferrites, and the contents of granular bainite and lath bainite are low. The orientation of this type of structure is very complex. By forcing the crack to continuously change its propagation direction during the propagation process, the crack propagation is effectively hindered, thereby improving the low-temperature toughness of the weld metal.

[0089] Figure 4-6 The images show the surface and cross-sectional morphology of the laser-arc hybrid weld seam of the welding wire in Example 1, which is a typical specification. It can be seen that the deposited metal has good spreadability and no defects. The crack resistance of the welding wire in Example 1 was tested using the Padon crack resistance and window crack resistance testing methods. By dissecting the weld seam, it was found that no cracks were generated in the weld metal without preheating or postheating under room temperature conditions. This indicates that the welding wire of the present invention has good crack resistance and has an excellent basis for engineering applications.

[0090] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A 590MPa grade solid welding wire, characterized in that, The chemical composition of the welding wire, by mass percentage, is as follows: C: 0.02-0.05%, Si: 0.20-0.40%, Mn: 0.9-1.3%, Ni: 2.1-2.6%, Cr: ≤0.3%, Mo: 0.28-0.6%, V: 0.03-0.06%, Ti: ≤0.05%, S≤0.010%, P≤0.015%, with the balance being Fe and unavoidable impurities.

2. The 590MPa grade solid welding wire according to claim 1, characterized in that, The chemical composition of the welding wire, by mass percentage, is as follows: C: 0.036%, Si: 0.308%, Mn: 1.09%, Ni: 2.57%, Mo: 0.626%, V: 0.051%, Ti: 0.027%, S: 0.0032%, P: 0.0087%, with the remainder being Fe and unavoidable impurities.

3. The 590MPa grade solid welding wire according to claim 1, characterized in that, The chemical composition of the welding wire, by mass percentage, is as follows: C: 0.047%, Si: 0.319%, Mn: 1.06%, Ni: 2.48%, Cr: 0.206%, Mo: 0.607%, V: 0.051%, Ti: 0.031%, S: 0.0030%, P: 0.010%, with the remainder being Fe and unavoidable impurities.

4. The 590MPa grade solid welding wire according to claim 1, characterized in that, The chemical composition of the welding wire, by mass percentage, is as follows: C: 0.035%, Si: 0.309%, Mn: 1.33%, Ni: 2.49%, Mo: 0.612%, V: 0.051%, Ti: 0.027%, S: 0.0030%, P: 0.0092%, with the remainder being Fe and unavoidable impurities.

5. The 590MPa grade solid welding wire according to claim 1, characterized in that, The chemical composition of the welding wire, by mass percentage, is: C: 0.029%, Si: 0.310%, Mn: 0.92%, Ni: 2.13%, Mo: 0.28%, V: 0.031%, Ti: 0.025%, S: 0.0046%, P: 0.0061%, with the remainder being Fe and unavoidable impurities.

6. The 590MPa grade solid welding wire according to any one of claims 1-5, characterized in that, The yield strength of the weld metal deposited by the welding wire Impact absorption energy of 593–704 MPa at -50°C The J ranges from 122 to 146.

7. A laser-arc hybrid welding process, using the 590MPa grade solid welding wire as described in any one of claims 1-5, characterized in that, The welding process parameters are as follows: laser power 1.0~10.0kW, defocusing amount -2~+2mm, wire spacing 2~5mm, wire feed speed 7~12m / min, welding speed 50~200cm / min, and shielding gas flow rate 15~25L / min.

8. The laser-arc hybrid welding process according to claim 7, characterized in that, use The mixed gas is used as a welding shielding gas.

9. A welded joint, characterized in that, It is welded using the laser-arc hybrid welding process described in any one of claims 7-8.

10. The welded joint according to claim 9, characterized in that, The weld metal microstructure of the welded joint is mainly acicular ferrite. At -50℃, the impact specimen size is 5×10×55mm, corresponding to the impact absorbed energy of the weld metal. The impact energy is 87–96 J, and the dimensions of the impact specimen are 10 × 10 × 55 mm. This corresponds to the impact absorbed energy of the weld metal. The value is 122–141 J.

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