High-corrosion-resistance CO2 gas shielded welding material and application thereof

Abstract

The invention belongs to the field of corrosion-resistant steel welding materials for railway vehicles, and particularly relates to a high-corrosion-resistant CO2 gas shielded welding material and application thereof. The invention provides a CO2 gas shielded welding material with high corrosion resistance. The CO2 gas shielded welding material comprises the following elements in percentage by mass: 0 to 0.04 percent of C, 0.85 to 1.10 percent of Si, 0.90 to 1.15 percent of Mn, 1.50 to 2.70 percent of Cr, 2.10 to 2.40 percent of Ni, 0.18 to 0.34 percent of Cu, 0.035 to 0.055 percent of Ti, 0.015 to 0.035 percent of Zr, 0.035 to 0.055 percent of Ce, 0.025 to 0.050 percent of V, 0.0015 to 0.003 percent of B, less than or equal to 0.005 percent of O, 0.003 to 0.009 percent of N and the balance of Fe and other inevitable impurities.

Description

Technical Field

[0001] The invention belongs to the field of corrosion-resistant steel welding materials for railway vehicles, and in particular relates to a highly corrosion-resistant CO2 gas shielded welding material and an application thereof. Background Art

[0002] my country's railways have been extended to various regions. The environment and conditions of railway vehicle migration are complex and harsh, which requires high performance of railway vehicle steel. At the same time, with the development of railway vehicles towards heavy load, high speed and lightweight, the comprehensive performance requirements of railway vehicle steel are higher, not only requiring excellent corrosion resistance, but also excellent mechanical properties. Traditional railway vehicles are generally made of 09CuPCrNi and O450NQR1 steel, but their corrosion resistance is poor and their service life is short, which makes it difficult to meet the development needs of heavy load, lightweight and long life of railway vehicles. Q350EWR1-Q450EWR1 grade railway vehicle steel has excellent corrosion resistance and high strength. In recent years, it has been widely used in the field of railway vehicle steel. In order to ensure excellent crack resistance and low-temperature impact toughness in the engineering application of this series of steel, gas shielded welding solid wire and submerged arc welding wire are generally used. Among them, gas shielded welding solid wire is mainly argon-rich gas-protected solid wire, and is widely used in the welding of flat-position fillet joints and butt joints of high-corrosion-resistant steel. However, the welding parameters and actual operation are highly variable during component splicing and assembly welding and vertical welding of joint components. Due to the small molten pool volume and fast cooling rate during argon-rich gas shielded welding, it is easy for the gas generated by the metallurgical reaction to not have time to overflow from the molten pool and cause porosity defects. In vertical welding, arc breaking problems are also prone to occur during argon-rich gas welding, and the weld continuity is poor. CO2 gas shielded welding has low sensitivity to changes in welding parameters, high arc stability, and easy to obtain gas at low cost. It is particularly suitable for component standing welding and splicing welding. However, when using CO2 gas shielded welding, the oxidizing atmosphere is high, the welding spatter is large, and the weld often needs multiple grinding treatments. In addition, the strong oxidizing atmosphere causes serious burnout of alloy elements. The existing solid welding wire uses CO2 gas for welding, and a large amount of hard and brittle phases such as granular bainite and M / A components are produced in the weld microstructure. The mechanical properties of the weld, especially the impact properties, are significantly reduced, and the corrosion properties are also reduced due to element burnout. Therefore, in the field of railway vehicles, CO2 gas shielded welding is almost not used, and there is little research on related CO2 gas shielded welding solid welding wire. Considering the needs of actual projects and the characteristics of good operability and low cost of CO2 gas shielded welding, it is necessary to develop a CO2 gas shielded welding solid welding wire for Q350EWR1-Q450EWR1 steel with small welding spatter and low alloy element burnout based on the relevant principles of metallurgy. Summary of the invention

[0003] To solve the above problems, the present invention provides a highly corrosion-resistant CO2 gas shielded welding material, comprising the following elements in percentage by mass: C: 0-0.04, Si: 0.85-1.10, Mn: 0.90-1.15, Cr: 1.50-2.70, Ni: 2.10-2.40, Cu: 0.18-0.34, Ti: 0.035-0.055, Zr: 0.015-0.035, Ce: 0.035-0.055, V: 0.025-0.050, B: 0.0015-0.003, O: ≤0.005, N: 0.003-0.009, and the balance is Fe and other inevitable impurities.

[0004] The present invention also provides a welding wire, the composition of which includes the above welding material.

[0005] Furthermore, the chemical composition of the welding wire is calculated by weight percentage to satisfy 0.09≤σ≤0.17, 0.04≤ω≤0.12, wherein: σ=(Ti+2Zr+3Ce) / (Si+0.75Mn), ω=N / (B+2V).

[0006] The present invention also provides application of the welding material in railway vehicle welding.

[0007] The present invention has the following beneficial effects:

[0008] The invention provides a CO2 gas shielded welding wire suitable for welding high corrosion-resistant steel for railway vehicles of level Q350EWR1-Q450EWR1 and a welding method thereof. The impact energy of the weld metal at -40°C after welding by the welding wire and the welding process is higher than 65J, and the relative corrosion rate to the high corrosion-resistant steel is lower than 8.1%. The invention can effectively solve the problems of large welding spatters, low weld corrosion resistance and low impact toughness of the existing high corrosion-resistant steel welding wire for railway vehicles during CO2 gas shielded welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0010] Figure 1The present invention provides a comparison between the actual welding photos of the CO2 gas shielded welding wire provided in the present invention and the weld inclusions after welding and the CO2 gas shielded welding photos of the welding wire provided in the comparative example and the weld inclusions after welding, wherein (a1) is the actual welding photo of the CO2 gas shielded welding wire described in Example 2, and (a2) is the weld inclusions picture of the CO2 gas shielded welding wire after welding described in Example 2; (b1) is the CO2 gas shielded welding photo of the welding wire described in Comparative Example 1, and (b2) is the weld inclusions after CO2 gas shielded welding of the welding wire described in Comparative Example 1.

[0011] Figure 2 The microstructure scanning diagram of the weld metal after CO2 gas shielded welding wire provided by the present invention and the microstructure scanning diagram of the weld metal after CO2 gas shielded welding provided by the comparative example, wherein (a) is the microstructure scanning diagram of the weld after CO2 gas shielded welding wire described in Example 4, and (b) is the microstructure scanning diagram of the weld metal after CO2 gas shielded welding wire described in Comparative Example 2.

[0012] Figure 3 The present invention provides a CO2 gas shielded welding wire, and the surface rust layer morphology of the weld metal after 48 hours of accelerated corrosion test by immersion, and the surface rust layer morphology of the weld metal after 48 hours of accelerated corrosion test by immersion, provided by the comparative example, wherein (a) is the surface rust layer morphology of the weld metal after 48 hours of accelerated corrosion test by immersion, provided by the CO2 gas shielded welding wire described in Example 5, and (b) is the surface rust layer morphology of the weld metal after 48 hours of accelerated corrosion test by immersion, provided by the comparative example 3. DETAILED DESCRIPTION

[0013] Now, various exemplary embodiments of the present invention are described in detail. The methods in the examples are conventional methods unless otherwise specified, and the reagents used are conventional commercially available reagents or reagents prepared by conventional methods unless otherwise specified. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features and embodiments of the present invention.

[0014] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0015] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0016] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0017] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0018] Examples 1-7 and Comparative Examples 1-3

[0019] The invention provides a high corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof, wherein the wire is made of the following chemical components by mass percentage (wt.%): C: 0-0.04, Si: 0.85-1.10, Mn: 0.90-1.15, Cr: 1.50-2.70, Ni: 2.10-2.40, Cu: 0.18-0.34, Ti: 0.035-0.055, Zr: 0.015-0.035, Ce: 0.035-0.055, V: 0.025-0.050, B: 0.0015-0.003, O: ≤0.005, N: 0.003-0.009, and the balance is Fe and other inevitable impurities.

[0020] The invention provides a high corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof, wherein C is included in the amount of 0 to 0.04% by mass. By adding C and controlling its content within the above range, the invention can make full use of the benefits of C in improving the processing performance of the welding wire and improving the strength and toughness of the weld, significantly reduce the generation of cracks during the drawing process of the welding wire, and avoid the generation of large-sized hard and brittle carbides in the weld.

[0021] The invention provides a high corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof, wherein Si is contained by mass percentage: 0.85-1.10%. The invention can make full use of the characteristics of Si in deoxidation, improving corrosion resistance and reducing molten pool viscosity by adding Si and controlling its content within the above range. The CO2 gas shielded welding has a high oxidizing atmosphere, and a low Si content is not conducive to obtaining a weld with high weld pool fluidity and low oxygen content. The corrosion resistance of the weld can be significantly increased with the increase of Si content, but Si that is too high will be dissolved into the weld, significantly increasing the number and size of the ferrite and hard phase M / A components of the side plate strip.

[0022] The invention provides a high corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof, wherein Mn is contained by mass percentage: 0.9-1.15%. Mn in the welding wire can combine with Si to deoxidize the weld and reduce welding spatter, and can also play a role in removing S and FeO in the weld. However, when the Mn content is too high, the stiffness of the welding wire is high, which is not conducive to actual welding.

[0023] The invention provides a high corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof, wherein Cr is contained by mass percentage: 1.50-2.70%. The increase of Cr content in the weld will improve the compactness of the rust layer and increase the content of α-FeOOH thereof. When a certain amount of Cr is added, it can also play a role of solid solution strengthening. However, when the amount of Cr is excessive, the proportion of ferrite in the side plate strip and the hard phase M / A component in the weld will be increased.

[0024] The present invention provides a highly corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof, which contains Ni: 2.10-2.40% by mass. The increase in Ni content in the weld can not only increase the corrosion resistance, but also refine the ferrite grains and reduce the problem of low low-temperature toughness caused by the high oxidizing atmosphere in CO2 gas shielded welding. However, when the Ni content is too high, it will cause segregation inside the wire rod and reduce the drawing performance. During the welding process, the excessively high Ni content will increase the viscosity of the molten pool, which is not conducive to the discharge of pores and the like, and is not conducive to obtaining good metallurgical quality.

[0025] The invention provides a high corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof, which contains Cu: 0.18-0.34% by mass. During the corrosion process of steel, Cu can be enriched on its surface to form a dense oxide layer, while making the inner rust layer finer and denser to prevent further corrosion. However, excessive Cu content will increase the tendency of weld hot cracking. Considering that the welding wire developed in this invention has a copper plating layer, 0.1%-0.15% Cu will transition to the weld during welding, so the Cu addition amount in the welding wire is 0.18-0.34%.

[0026] The present invention provides a high corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof, which contains Ti by mass percentage: 0.035-0.055%. Ti can reduce the welding spatter rate during welding, and it is very easy to react with oxygen and nitrogen to form inclusions or second phase particles, which play the role of pinning the original austenite grain boundaries to refine the grains and the ferrite nucleation sites. However, too much Ti content can easily lead to large-sized inclusions in the weld, thereby increasing the sensitivity of cracks.

[0027] The present invention provides a high corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof, which contains Zr: 0.015-0.035% by mass. Adding Zr to the weld can increase the fluidity of the molten pool and significantly reduce the probability of the occurrence of hydrogen pores. At the same time, the oxide generated by the reaction of Zr and oxygen can also serve as an effective nucleation site for acicular ferrite. However, too much Zr content will significantly improve the hardenability, promote the formation of bainite, and increase the crack sensitivity of the weld.

[0028] The present invention provides a high corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof, which contains Ce in percentage by mass: 0.035-0.055%. The addition of Ce in the weld is beneficial to the spheroidization of silicate inclusions, promotes their dispersed distribution, reduces crack sensitivity, and its enrichment on the surface of inclusions can also effectively play the role of needle-shaped ferrite nucleation site. However, an increase in Ce content will cause difficulties in smelting welding wire steel and increase the spatter rate during welding.

[0029] The present invention provides a high corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof, which contains V by mass percentage: 0.025-0.050%. It is generally believed that V solid solution in the weld metal will reduce weldability and increase the tendency to crack, but if V exists in the form of precipitation and adheres to the surface of inclusions, it can significantly improve the nucleation of acicular ferrite and refine the structure of the weld.

[0030] The present invention provides a high corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof, which contains B by mass percentage: 0.0015-0.003%. The B element is solid-dissolved in the weld metal and can be concentrated at the grain boundary, which plays a role in inhibiting grain boundary migration and inhibiting the production of proeutectoid ferrite. The B element and the N element precipitate and adhere to the surface of the inclusions, which can also play the role of an effective nucleation site for ferrite. However, B is an element that significantly improves hardenability. When its content is too high, it will increase the sensitivity of cracks.

[0031] In a highly corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof provided by the present invention, O in the welding wire is required to be ≤0.005wt.%, and N is 0.003-0.009wt.%, and the low oxygen content in the weld can reduce the oxidizing atmosphere of CO2 gas shielded welding and reduce spatter. The control of a certain amount of N can give full play to the role of VN particles and BN particles formed by adding V and B in the welding wire as nucleation sites for acicular ferrite.

[0032] In the present invention, a highly corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof are provided, wherein the mass percentages of Ti, Zr, Ce, Si and Mn elements are controlled to meet 0.09≤σ≤0.17, wherein σ=(Ti+2Zr+3Ce) / (Si+0.75Mn). In CO2 gas shielded welding, the oxidizing atmosphere is relatively high, and the strong oxidizing effect of Ti, Zr and Ce effectively protects the transition of Si and Mn to the weld, thereby reducing the spatter of CO2 gas shielded welding. Meanwhile, the proportional addition of Ti, Zr, Ce and Si and Mn can regulate the morphology and size of inclusions with silicate as the core, spheroidize the inclusions, and distribute them more dispersedly and finely in the weld, thereby reducing the crack sensitivity and the pitting corrosion problem of the inclusions.

[0033] In the present invention, a high corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof, the ratio of V, B and N is controlled to meet 0.04≤ω≤0.12, and the ω=N / (B+2V). In CO2 gas shielded welding, a large amount of Cr, Ni, Cu and other elements are added to ensure that the corrosion resistance of the weld metal matches that of the base material, which results in the weld structure being mainly coarse block ferrite and granular bainite. Under the action of .09≤σ≤0.17, we achieved the dispersed and refined distribution of inclusions in the weld, but the bainitic-ferrite transformation range is still dominated by granular bainite nucleated at the grain boundary, rather than acicular ferrite nucleated on the inclusions. By regulating 0.04≤ω≤0.12, the precipitation of VN and BN on the surface of inclusions is promoted, the mismatch between inclusions and acicular ferrite is reduced, and the nucleation of acicular ferrite is promoted, thereby achieving the effect of significantly refining the weld structure.

[0034] In order to further illustrate the present invention, a highly corrosion-resistant CO2 gas shielded welding wire for railway vehicles with excellent weld impact toughness and a welding method thereof provided by the present invention are described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0035] Seven furnaces of welding wire steel of the embodiment of the present invention and three furnaces of welding wire steel of the comparative example were refined in a 75kg vacuum induction furnace, wherein the element ratio of the welding wire steel of the embodiment of the present invention meets the requirements of the present invention. The welding wire steel of the embodiment and the comparative example were melted and cast in sequence according to a certain element composition ratio to obtain a cast alloy billet, and the composition of the welding wire steel of the embodiment and the comparative example was detected according to GB / T4336 "Spark Source Atomic Emission Spectroscopy Analysis Method for Carbon Steel and Medium and Low Alloy Steel (Conventional Method)", and the specific chemical composition is shown in Table 1.

[0036] Table 1 Chemical composition of welding wire steel of Examples 1 to 7 and Comparative Examples 1 to 3 (wt.%, balance Fe)

[0037] serial number C Si Mn P S Cr Ni Cu Mo Ti Zr Ce B V Nb O N σ ω Example 1 0.03 1.06 1.02 0.010 0.004 1.89 2.15 0.23 - 0.038 0.017 0.041 0.0017 0.034 - 0.004 0.005 0.11 0.07 Example 2 0.02 0.95 1.07 0.009 0.005 2.06 2.33 0.30 - 0.041 0.020 0.039 0.0018 0.041 - 0.005 0.007 0.11 0.08 Example 3 0.04 0.99 0.99 0.010 0.004 2.53 2.19 0.22 - 0.047 0.031 0.051 0.0026 0.029 - 0.004 0.006 0.15 0.10 Example 4 0.03 0.91 0.96 0.008 0.005 2.16 2.24 0.19 - 0.050 0.027 0.048 0.0021 0.038 - 0.003 0.004 0.15 0.05 Example 5 0.04 1.06 1.13 0.009 0.004 1.67 2.11 0.32 - 0.039 0.029 0.036 0.0025 0.047 - 0.004 0.006 0.11 0.06 Example 6 0.03 0.88 1.05 0.011 0.003 2.43 2.36 0.24 - 0.052 0.031 0.047 0.0019 0.043 - 0.003 0.008 0.15 0.09 Example 7 0.04 0.97 0.95 0.007 0.005 2.37 2.25 0.28 - 0.045 0.019 0.045 0.0023 0.039 - 0.005 0.005 0.13 0.06 Comparative Example 1 0.07 0.55 0.81 0.009 0.005 1.35 4.08 0.21 - 0.08 - - - 0.03 - 0.003 0.005 0.07 0.08 Comparative Example 2 0.09 0.60 1.80 0.010 0.004 1.10 0.76 0.33 0.05 0.15 - - - - 0.05 0.005 0.006 0.08 / Comparative Example 3 0.05 0.55 0.65 0.009 0.004 1.00 3.55 0.52 0.34 0.12 - - - - - 0.004 0.007 0.12 /

[0038] Forge the welding wire steel into a cross section of 50×50mm 2 The forged billet is kept at 1150-1250℃ for 3h, then wire rod rolled at 850-900℃, sized and wired at 810-830℃, and slowly cooled at 730-480℃ for 10min to finally prepare a billet with a diameter of Finally, the wire rod is processed into φ1.2mm finished welding wire through the processes of pickling, borax treatment, rough drawing (φ5.5mm→φ2.35mm), primary fine drawing (φ2.35mm→φ1.25mm), secondary fine drawing (φ1.25mm→φ1.175mm) and copper plating.

[0039] Performance measurement

[0040] The processed finished welding wires of Examples 1 to 7 and Comparative Examples 1 to 3 were subjected to welding tests of typical joints. The specific welding parameters of each welding wire are shown in Table 2. The welding test plate is made of Q350EWR1 corrosion-resistant steel with a thickness of 16 mm. The steel plate has a yield strength of 370 MPa, a tensile strength of 537 MPa, an elongation of 22.5%, and a low-temperature impact of -40°C of 214 J.

[0041] Table 2 CO2 gas shielded welding parameters of welding wires in Examples 1 to 7 and Comparative Examples 1 to 3

[0042]

[0043] The welding process of the welding wire was observed during the welding process, and the actual welding photos of Example 2 and Comparative Example 1 are shown in FIG. Figure 1 (a1) and Figure 1 (b1), the welding wire of the present invention has good weld formation during the welding process, almost no arc breaking occurs during the welding process, the weld has good continuity, and the welding spatter rate is low. However, the comparative welding wire often has arc breaking problems during welding, the weld continuity is poor, and the spatter rate is high during welding, and fine grinding is required after welding one layer. After welding is completed, the welding section is cut at the defect-free part of the weld, and the chemical composition of the weld metal after each welding wire is welded is tested according to GB / T 4336 "Spark Source Atomic Emission Spectrometry Analysis Method for Carbon Steel and Medium and Low Alloy Steel (Conventional Method)", and the specific results are shown in Table 3. The results show that the welding wire developed by the present invention has a low Si and Mn burnout rate through the optimized ratio of alloy elements.

[0044] Table 3 Chemical composition of weld metal after CO2 gas shielded welding of Examples 1 to 7 and Comparative Examples 1 to 3 (wt.%, remainder Fe)

[0045]

[0046]

[0047] The macroscopic cross-sections of the joints of Examples 1 to 7 and Comparative Examples 1 to 3 were sanded with 100x to 1500x sandpaper, and then the weld inclusions in each sample were observed under a 200x metallographic microscope. The weld inclusion observation diagrams of Example 2 and Comparative Example 1 are shown in FIG. Figure 1 (a2) and Figure 1 (b2). At the same time, the 1mm 2 The size distribution of inclusions in the region was statistically analyzed, and the results are shown in Table 4. The results show that after the welding wire of the present invention is welded with CO2 gas protection, the inclusions in the weld are dispersedly distributed, and the inclusions in the weld are clustered. According to the size statistics in Table 4, it can be found that the number of inclusions in the weld of the welding wire of this embodiment with a size greater than 1 μm is small, accounting for about 10%, while in the comparative example, the number of inclusions greater than 1 μm accounts for about 50%.

[0048] Table 4 Size distribution of inclusions in CO2 gas shielded welding seams of Examples 1 to 7 and Comparative Examples 1 to 3

[0049]

[0050] The weld metal samples that passed the flaw detection in Examples 1 to 7 and Comparative Examples 1 to 3 were sampled and tested for mechanical properties and corrosion properties of the weld metal. The tensile properties of the weld metal were sampled and tested in accordance with GB / T 228.1, and the impact sampling and performance testing were in accordance with GB / T 2650. Three impact samples were taken for each sample to reduce errors. For the detection of weld metal corrosion performance, according to TB 2374-2008 "Atmospheric Corrosion Resistant Steel and Stainless Steel Welding Materials for Railway Vehicles" and TB 2375-1993 "Cyclic Immersion Corrosion Test Method for Weathering Steel for Railways" standards, a 0.01 mol / L NaHSO3 solution was used to simulate the industrial atmospheric environment, and an accelerated corrosion test of Q350EWR1 base material and weld metal was carried out in a cyclic immersion accelerated corrosion test box for 120 hours. The relative corrosion rate of the base material and the weld metal of the embodiment and the comparative example at 120 hours was calculated (relative corrosion rate = | (base material weight loss - weld metal weight loss) / base material weight loss × 100% |) to evaluate the atmospheric corrosion resistance of the base material and the weld metal. The test results of mechanical properties and corrosion properties are shown in Table 5.

[0051] Table 5 Test results of corrosion performance and mechanical properties of weld metal after CO2 gas shielded welding of Examples 1 to 7 and Comparative Examples 1 to 3

[0052]

[0053] It can be seen from the mechanical properties test results in Table 5 that the strength of the embodiment and the comparative example can match that of Q350EWR1, but compared with the impact toughness of the embodiment, the -40°C low-temperature impact toughness of the CO2 gas shielded welding weld metal of the comparative example is significantly reduced and can only be maintained at about 35J. By scanning and observing the weld tissues of the embodiment and the comparative example, it can be found that Figure 2 As shown, the weld metal of the embodiment has high density of acicular ferrite, while the weld of the comparative example has a lower amount of acicular ferrite, which is mainly composed of granular bainite and coarse ferrite. High-density acicular ferrite can provide a large-angle grain boundary that has a crack extension effect, effectively improving the crack extension function. In addition, the inclusion size in the embodiment is relatively small (such as Figure 1 ), which further reduces the crack sensitivity and improves the crack initiation work.

[0054] The results of the accelerated corrosion test of the weld metal after CO2 gas shielded welding of Examples 1 to 7 and Comparative Examples 1 to 3 also indicate that the relative corrosion rate of the weld metal of the Examples to the parent material is between 6.74% and 8.10%, which meets the requirement of less than 10% in the railway vehicle standard, indicating that the weld metal can match the parent material, while the relative corrosion rate of the comparative example to the parent material is higher than 13%, indicating that the corrosion performance of the metal after CO2 gas shielded welding of the comparative example welding wire is poor. Scanning and analyzing the rust layer on the surface of the samples after 48h of the accelerated corrosion test of the Examples and Comparative Examples can be found. Figure 3 The rust layer on the surface of the weld metal in the comparative example is relatively loose, unevenly distributed, and has cracks, while the rust layer on the surface of the weld metal in the embodiment is evenly distributed and has a high density, indicating that the optimized ratio of alloy elements in the embodiment is conducive to the formation of a stable and dense rust layer, which is conducive to the CO2 gas shielded welding weld metal to obtain high corrosion resistance.

[0055] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A highly corrosion-resistant CO2 gas shielded welding material, characterized in that: Including the following elements in mass percentage: C: 0-0.04, Si: 0.85-1.10, Mn: 0.90-1.15, Cr: 1.50-2.70, Ni: 2.10~2.40, Cu: 0.18-0.34, Ti: 0.035~0.055, Zr: 0.015-0.035, Ce: 0.035-0.055, V: 0.025-0.050, B: 0.0015-0.003, O: ≤0.005, N: 0.003-0.009, and the balance is Fe and other inevitable impurities.

2. A welding wire, characterized in that: The composition comprises the welding material as claimed in claim 1.

3. The welding wire according to claim 2, characterized in that The chemical composition of the welding wire is calculated by weight percentage to satisfy 0.09≤σ≤0.17, 0.04≤ω≤0.12, wherein: σ=(Ti+2Zr+3Ce) / (Si+0.75Mn), ω=N / (B+2V).

4. Use of the welding material as claimed in claim 1 in railway vehicle welding.

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