A welding material with low weld porosity and its application

Abstract

This invention belongs to the field of welding materials for corrosion-resistant steel used in railway vehicles, specifically relating to a welding material with low weld porosity and its application. This invention provides a high-corrosion-resistant argon-rich shielded welding material for railway vehicles with low weld porosity, comprising the following elements by mass percentage: C: 0-0.05, Si: 0.65-0.80, Mn: 1.20-1.50, Cr: 1.70-2.50, Ni: 1.50-2.00, Cu: 0-0.15, Mo: 0-0.1, Ti: 0.02-0.03, Ca: 0-0.05, Mg: 0-0.03, Y: 0.01-0.03, B: 0-0.001, O: ≤0.004, N: ≤0.006, with the balance being Fe and other unavoidable impurities.

Description

Technical Field

[0001] This invention belongs to the field of welding materials for corrosion-resistant steel used in railway vehicles, and specifically relates to a welding material with low weld porosity and its application. Background Technology

[0002] With the development of steel smelting technology and the increasing demands for high-speed, heavy-load, and low-cost railway vehicles, the main materials for railway vehicle bodies have evolved from ordinary low-strength carbon steel to low-strength atmospheric corrosion-resistant steel and then to high-strength atmospheric corrosion-resistant steel. Currently, high corrosion-resistant steels of grades Q350EWR1-Q450EWR1 have been widely developed in the railway vehicle field, primarily for welded structural components. Since railway vehicles themselves must withstand dynamic loads, high requirements are placed on the crack resistance of joints. Therefore, gas-shielded solid welding wire and submerged arc welding wire, which offer good weld metal crack resistance, are commonly used in the welding process. In particular, argon-rich solid welding wire exhibits less spatter, more stable droplet transfer, and excellent weld impact resistance, making it widely used in high corrosion-resistant steel fillet and butt joints. However, argon-rich welding wire results in a small weld pool volume and rapid weld cooling. Gases generated by the metallurgical reaction in the weld pool may not have enough time to escape and remain in the weld, forming porosity defects. To ensure a service life of 25 years, high corrosion-resistant steel incorporates 3-5.5 wt.% Cr and 0.1-0.65 wt.% Ni, among other corrosion-resistant elements. To ensure the weld metal matches the base metal, the welding wire also incorporates a high proportion of alloying elements such as Cr and Ni. During actual welding, a large amount of these alloying elements melt and transfer to the weld, increasing the viscosity of the weld pool and reducing its fluidity. This exacerbates the problem of high porosity in argon-protected welds of high corrosion-resistant steel, resulting in a lower flaw detection pass rate and a significantly higher risk of weld rework. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a welding material comprising the following elements by mass percentage: C: 0-0.05, Si: 0.65-0.80, Mn: 1.20-1.50, Cr: 1.70-2.50, Ni: 1.50-2.00, Cu: 0-0.15, Mo: 0-0.1, Ti: 0.02-0.03, Ca: 0-0.05, Mg: 0-0.03, Y: 0.01-0.03, B: 0-0.001, O: ≤0.004, N: ≤0.006, with the balance being Fe and other unavoidable impurities.

[0004] The present invention also provides a welding wire comprising the above-mentioned welding materials.

[0005] Furthermore, the diameter of the welding wire is 1.2 mm, and the thickness of the copper plating layer on the surface of the welding wire is 0.19-0.22 μm.

[0006] Furthermore, the welding wire contains at least three of Ti, Ca, Mg, Y and B; the chemical composition, calculated by weight percentage, satisfies: 0.02≤α≤0.07, 0.04≤γ≤0.60, where: α=(Ti+1 / 2Ca+1 / 2Mg+3Y) / (Si+Mn); γ=Ni+7Cu+15Mo-Cr-Si.

[0007] The present invention also provides the application of the above-mentioned welding materials in argon-rich shielded welding.

[0008] The present invention has the following beneficial effects:

[0009] This invention, by limiting the content of each chemical element in the welding wire and proposing innovative technical requirements, precisely controls the addition amount of certain key elements to leverage the crucial regulatory role of elemental ratios on the comprehensive properties of argon-rich shielded welds, including metallurgical quality, corrosion resistance, and mechanical properties. This results in argon-rich shielded welding wires specifically designed for high corrosion-resistant steels (Q350EWR1-Q450EWR1), exhibiting a weld metal porosity of less than 1% under a heat input process of 10-25 kJ / cm, a relative corrosion rate of less than 7.4% with high corrosion-resistant steel, and an impact toughness of not less than 75 J at -40℃. These welding wires can be widely used in the welding of fillet and butt joints in parallel welding of high corrosion-resistant steels. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 Morphology of argon-rich shielded welding wire for examples and comparative examples;

[0012] Figure 2 The appearance morphology and radiographic testing results of argon-rich shielded welds in the examples and comparative examples;

[0013] Figure 3 Macroscopic morphology of argon-rich shielded welds after 48h and 72h of accelerated corrosion immersion tests. Detailed Implementation

[0014] Various exemplary embodiments of the present invention are now described in detail. Unless otherwise specified, the methods used in the embodiments are conventional methods, and the reagents used are commercially available reagents or reagents prepared using conventional methods. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and embodiments of the present invention.

[0015] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0016] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0017] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0018] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0019] Examples 1-7 and Comparative Examples 1-3

[0020] This invention provides a high corrosion-resistant argon-rich shielded welding wire and rod for railway vehicles with low weld porosity, comprising the following elements by mass percentage: C: 0-0.05, Si: 0.65-0.80, Mn: 1.20-1.50, Cr: 1.70-2.50, Ni: 1.50-2.00, Cu: 0-0.15, Mo: 0-0.1, Ti: 0.02-0.03, Ca: 0-0.05, Mg: 0-0.03, Y: 0.01-0.03, B: 0-0.001, O: ≤0.004, N: ≤0.006, with the balance being Fe and other unavoidable impurities.

[0021] The aforementioned high corrosion-resistant argon-rich shielded welding wire and rod for railway vehicles, characterized by low weld porosity, are welded using a mixed gas comprising 80%–95% Ar and 5%–20% CO2 and / or O2. The welding wire contains three or four of the elements Ti, Ca, Mg, Y, and B. The mass percentage content of each element satisfies the following conditions: 0.02 ≤ α ≤ 0.07, where α = (Ti + 1 / 2 Ca + 1 / 2 Mg + 3Y) / (Si + Mn); 0.04 ≤ γ ≤ 0.60, where γ = Ni + 7Cu + 15Mo - Cr - Si.

[0022] The present invention comprises C: 0-0.05 wt.% by mass percentage. C is one of the strongest alloying elements in terms of strengthening effect. Adding a certain amount of C to steel is beneficial to improving the drawability of welding wire steel and reducing cracks on the surface of wire rod. However, adding too much C to the welding wire will deteriorate the welding performance, and the plasticity and toughness of the weld will be significantly reduced.

[0023] Based on mass percentage, this invention includes Si: 0.65-0.80 wt.%. Si mainly plays a strong deoxidizing role in the weld, reducing the viscosity of the weld pool, improving the fluidity of the weld pool, and improving the strength and toughness of the weld within a certain range. At the same time, Si can also form a Si-rich protective film on the steel surface and refine α-FeOOH, thereby reducing the corrosion rate of the steel. However, excessive Si will cause coarse M / A components and side strip ferrite to appear in the weld.

[0024] The present invention comprises Mn at a mass percentage of 1.2-1.5 wt.%. The main function of Mn in the weld is similar to that of Si, acting as a deoxidizer. It can also combine with Si to increase the width and depth of the weld pool. In addition, Mn can significantly lower the phase transformation initiation temperature and refine the weld microstructure. However, increased Mn content can increase segregation within the steel plate, affecting the drawability of the welding wire rod.

[0025] The present invention comprises Cr: 1.70-2.50 wt.% by mass percentage. The main role of Cr in the present invention is to improve the weather resistance of the weld metal. With the addition of Cr, a dense passivation film can be formed on the surface of the weld metal, which significantly improves the atmospheric corrosion resistance. Furthermore, the corrosion resistance increases with the increase of Cr content. However, excessive Cr content will have an adverse effect on weldability. Coarse M / A components and side strip ferrite are easily generated in the weld microstructure, which reduces the toughness of the weld.

[0026] The present invention comprises Ni at a mass percentage of 1.50-2.00 wt.%. Adding Ni to the weld seam is beneficial for forming a stable and dense rust layer on the steel surface, and it can also improve the low-temperature toughness of the steel plate, significantly increasing the low-temperature toughness of the weld metal and effectively preventing network cracking caused by Cu hot brittleness. However, excessive Ni addition will significantly increase the viscosity of the molten pool, reduce fluidity, and deteriorate the metallurgical quality of the weld seam. Furthermore, the large addition of Ni will significantly increase costs.

[0027] The present invention comprises Cu: 0-0.15 wt.% by mass percentage. Increasing the Ni content in the weld can also significantly improve corrosion resistance. At the same time, the addition of a certain amount of Cu is also beneficial to the formation of ε-Cu in the weld, which improves the strength of the weld. However, if the Cu content is too high, brittle cracks will be generated in the steel plate, affecting the quality of the wire rod and welding wire. A high Cu content in the weld will increase crack sensitivity. Considering that copper plating on the surface of the welding wire will transfer Cu element to the weld, the Cu content added to the welding wire is 0-0.15 wt.%.

[0028] The present invention comprises Mo: 0-0.10 wt.% by mass percentage. Appropriate addition of Mo to the weld can improve the rust layer structure, and its combined effect with Si and Ni increases the density of the rust layer, thereby improving atmospheric corrosion resistance. Simultaneously, Mo can expand the bainite region and refine the weld microstructure; however, excessive Mo content can lead to the formation of high-density hard and brittle M / A phases in argon-rich shielded welds.

[0029] The present invention comprises Ti: 0.02-0.03 wt.% by mass percentage. The main function of Ti in the weld is deoxidation. Its ability to combine with oxygen is stronger than that of Mn and Si, which is beneficial to protecting the transition of Si and Mn into the weld. At the same time, the oxide of Ti of 0.1-0.3 μm is an effective nucleation site for acicular ferrite. However, when the Ti content increases, the size of inclusions will increase. Large inclusions often appear in welds with high Ti content, which increases crack sensitivity. At the same time, large inclusions are also strong pitting corrosion zones, which can easily destroy the dense oxide film formed by elements such as Cr and Ni on the surface of the weld metal, significantly reducing corrosion resistance.

[0030] The present invention comprises Ca: 0-0.05 wt.% by mass percentage. Ca is also a strong deoxidizing element. In the welding pool reaction, it can react with compounds with high melting points to form calcium salts, thereby reducing the viscosity of the welding pool and improving its fluidity. The addition of Ca can also denature inclusions, significantly reducing the number of inclusions in the weld. At the same time, the addition of Ca to the welding wire can also reduce the phenomenon of rust splattering during welding. However, the excessive addition of Ca can cause the molten pool reaction to be violent, which is not conducive to obtaining excellent weld metallurgical quality.

[0031] The present invention comprises Mg: 0-0.03 wt.% by mass percentage. Mg is also a strong deoxidizing element. Its reaction with oxygen to form Mg oxide can pin the original austenite grain boundaries, significantly reducing the size of austenite grains. At the same time, through Mg treatment, micron-sized magnesium oxide and sulfide composite inclusions can be formed, controlling the size and morphology of the inclusions and inducing acicular ferrite to nucleate on the inclusions. However, when the Mg content is too high, it is easy to form a low-melting-point eutectic structure with other metals, which can easily lead to crystallization cracks in the weld.

[0032] The present invention comprises Y (yttrium) at a mass percentage of 0.01–0.03 wt.%. The introduction of metallic Y into the weld can improve the fluidity of the weld pool, accelerate the expulsion of pores, and reduce porosity. Simultaneously, the addition of Y can react with oxygen and nitrogen, purifying the weld. However, the excessive addition of Y can lead to its precipitation along grain boundaries, increasing grain boundary brittleness and hindering the attainment of high weld toughness.

[0033] The present invention comprises B: 0-0.001 wt.% by mass. B can promote grain boundary movement and recrystallization, making the grain boundaries smoother, which is beneficial for improving weld morphology and reducing welding defects. It can also combine with Mo to refine the weld microstructure. However, increasing the B content will improve the hardenability of the weld metal; excessively high content will significantly increase the joint hardness and weld crack susceptibility.

[0034] By mass percentage, this invention strictly controls the O content in the welding wire to be no higher than 0.004 wt.% and the N content to be no higher than 0.006 wt.%.

[0035] In this invention, the mass percentage content of each element in the high corrosion resistance argon-rich shielded welding wire and wire rod for railway vehicles with low weld porosity satisfies the following conditions: 0.02≤α≤0.07, where α=(Ti+1 / 2Ca+1 / 2Mg+3Y) / (Si+Mn); 0.04≤γ≤0.60, where γ=Ni+7Cu+15Mo-Cr-Si;

[0036] For argon-enriched shielded welding, the molten pool volume is small and the cooling rate is fast during actual welding. Gases generated during the welding metallurgical reaction stage can easily fail to escape in time, leading to porosity. This is especially true for welding wires used in corrosion-resistant steels containing high Cr and Ni content, where the increased viscosity of the molten pool exacerbates the porosity problem, with porosity typically exceeding 15%. In this invention, the addition of Ca, Y, and Si elements significantly reduces the viscosity of the molten pool and improves its fluidity. Simultaneously, controlling the ratio α of Ti, Ca, Mg, Y to Si and Mn within the range of 0.02-0.07 increases the molten pool volume, reduces the cooling rate of the molten metal in the weld, and facilitates porosity escape. Furthermore, it controls the type and size of inclusions, increasing the number of acicular ferrite nucleation sites and preventing the formation of high-density, large-sized inclusions.

[0037] In addition, this invention regulates the elemental ratio γ between Ni, Cu, Mo, Cr, and Si in the range of 0.04-0.6. The addition of these elements can significantly increase the corrosion resistance of the weld metal. However, the increase of Cr and Si can easily lead to the appearance of coarse side-plate ferrite and hard phase M / A components in the weld microstructure. By regulating the ratio between Ni, Cu, Mo and Cr, and Si, the onset temperature of the austenite-ferrite phase transformation is reduced. Based on the above-mentioned regulation formula α increasing the number of acicular ferrite nucleation sites, the nucleation of acicular ferrite rather than granular bainite is promoted, significantly refining the weld microstructure and improving the weld toughness.

[0038] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, describes the high corrosion resistance argon-rich shielded welding wire and rod with low weld porosity for railway vehicles provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0039] Seven heats of welding wire steel according to the embodiments of the present invention and three heats of welding wire steel according to the comparative examples were produced in a 75kg vacuum induction furnace. The elemental composition of the welding wire steel according to the embodiments of the present invention meets the requirements of the present invention. The welding wire steels of the embodiments and the comparative examples were melted and cast sequentially according to a certain elemental composition ratio to obtain as-cast alloy billets. The composition of the welding wire steels of the embodiments and the comparative examples was analyzed according to GB / T4336 "Spark Source Atomic Emission Spectroscopy Analysis Method (Conventional Method) for Carbon Steel and Medium and Low Alloy Steels". The specific chemical composition is shown in Table 1.

[0040] Table 1. Chemical composition (wt.%, balance Fe) of welding wire steel in Examples 1-7 and Comparative Examples 1-3

[0041] Example 1 0.04 0.69 1.35 0.007 0.005 1.85 1.85 0.05 0.04 0.024 0 0.012 0.0009 0.015 - 0.004 0.005 0.037 0.26 Example 2 0.03 0.66 1.42 0.011 0.004 2.14 1.94 0.14 0.03 0.025 0.015 0 0 0.017 - 0.003 0.006 0.040 0.57 Example 3 0.05 0.78 1.26 0.009 0.004 2.34 1.85 0.1 0.07 0.027 0 0.023 0.0007 0.027 - 0.004 0.006 0.059 0.48 Example 4 0.03 0.68 1.37 0.009 0.005 1.97 1.89 0.12 0 0.021 0 0.026 0 0.018 - 0.003 0.005 0.043 0.08 Example 5 0.04 0.67 1.29 0.012 0.005 1.89 1.67 0.09 0.05 0.028 0.036 0.016 0 0.018 - 0.004 0.005 0.055 0.49 Example 6 0.05 0.78 1.44 0.008 0.003 1.96 1.98 0.12 0 0.029 0 0 0.005 0.025 - 0.003 0.006 0.047 0.08 Example 7 0.04 0.71 1.48 0.009 0.005 2.41 1.61 0.13 0.06 0.022 0.025 0 0.007 0.019 - 0.004 0.006 0.042 0.30 Comparative Example 1 0.01 0.51 0.89 0.011 0.004 1.35 3.50 0.25 - 0.04 - - 0.004 - - 0.004 0.005 0.029 3.39 Comparative Example 2 0.06 0.60 0.57 0.007 0.005 1.0 3.20 0.45 0.35 0.10 - - - - - 0.003 0.006 0.086 10 Comparative Example 3 0.08 0.58 0.75 0.009 0.004 1.30 4.0 0.25 - 0.11 - - - - 0.03 0.004 0.006 0.083 3.87

[0042] Performance Measurement and Result Analysis

[0043] The welding wire steel billet is forged into a cross section of 50x50mm. 2The billet is held at 1100-1140℃ for 3 hours, then descaled at 1020-1050℃, and rolled in multiple passes at 880-920℃. Sizing and wire drawing are then performed at 800-820℃. Subsequently, the 5.5mm sized wire rod is slowly cooled in an insulated hood at a temperature range of 740-465℃ for 630-670 seconds. The specific wire rod rolling process for the examples and comparative examples is shown in Table 2 below. Finally, the wire rod is processed into 1.2mm welding wire through pickling, borax treatment, rough drawing (φ5.5mm→φ2.55mm), first fine drawing (φ2.55mm→φ1.25mm), second fine drawing (φ1.25mm→φ1.175mm), and copper plating. Figure 1 The morphology of the wire rods after rolling in Example 5 and Comparative Example 3 was observed. The wire rod surface in the Example 5 was smooth, while the wire rod surface in the Comparative Example had cracks and peeling. This led to multiple wire breakage problems during the subsequent drawing of welding wire, which seriously affected the drawing efficiency and the quality of the finished welding wire.

[0044] Table 2. Welding wire rod rolling process parameters for Examples 1-7 and Comparative Examples 1-3

[0045]

[0046] Welding tests were conducted on typical butt joints of the welding wires prepared in Examples 1-7 and Comparative Examples 1-3. The specific welding process parameters are shown in Table 3. The test plates used for welding were made of Q450EWR1 corrosion-resistant steel with a thickness of 16mm, a yield strength of 485MPa, a tensile strength of 605MPa, an elongation of 21%, and a low-temperature impact of 205J at -40℃.

[0047] Table 3. Process parameters for argon-rich shielded welding of Examples 1-7 and Comparative Examples 1-3.

[0048]

[0049] After welding, the specimens were visually inspected, and the weld was examined using radiographic testing. The macroscopic morphology and radiographic photographs of the joints in Example 2 and Comparative Example 1 are shown below. Figure 1 The welding wire provided by this invention exhibits excellent weld formation, with no obvious internal defects under X-ray irradiation. In contrast, the weld surface of the comparative welding wire has an uneven texture and poor formation; under X-ray irradiation, pores of varying sizes can be observed. Samples were taken from the defect-free area, and the chemical composition of the weld metal from the examples and comparative examples was analyzed according to GB / T 4336 "Spark Source Atomic Emission Spectroscopy Analysis Method (Conventional Method) for Carbon Steel and Medium-Low Alloy Steel". The test results are shown in Table 4.

[0050] Table 4. Chemical composition (wt.%, balance Fe) of weld metals after argon-rich shielded welding in Examples 1-7 and Comparative Examples 1-3.

[0051] Example 1 0.03 0.61 1.22 0.009 0.004 1.83 1.84 0.17 0.04 0.010 0 0.005 0.0009 0.004 - 0.006 0.008 Example 2 0.03 0.60 1.34 0.010 0.005 2.11 1.93 0.21 0.03 0.008 0.005 0 0 0.006 - 0.007 0.009 Example 3 0.04 0.71 1.19 0.009 0.005 2.30 1.82 0.24 0.07 0.011 0 0.009 0.0007 0.009 - 0.007 0.008 Example 4 0.03 0.59 1.21 0.009 0.003 1.95 1.87 0.23 0 0.009 0 0.010 0 0.008 - 0.008 0.009 Example 5 0.04 0.60 1.16 0.008 0.004 1.85 1.67 0.21 0.05 0.011 0.012 0.006 0 0.006 - 0.007 0.009 Example 6 0.03 0.71 1.35 0.010 0.005 1.92 1.97 0.26 0 0.010 0 0 0.005 0.007 - 0.007 0.008 Example 7 0.04 0.62 1.35 0.009 0.005 2.38 1.60 0.27 0.06 0.008 0.007 0 0.007 0.007 - 0.007 0.007 Comparative Example 1 0.02 0.39 0.80 0.009 0.004 1.27 3.45 0.38 - 0.02 - - 0.004 - - 0.006 0.009 Comparative Example 2 0.04 0.48 0.48 0.008 0.004 0.95 3.18 0.56 0.34 0.05 - - - - - 0.008 0.008 Comparative Example 3 0.06 0.46 0.60 0.007 0.005 1.21 3.98 0.37 - 0.04 - - - - 0.025 0.011 0.009

[0052] Samples were taken from the welded joints provided in Examples 1-7 and Comparative Examples 1-3. Tensile specimens of the entire weld metal were taken along the weld direction according to GB / T 228.1 standard to complete the strength test. Impact specimens of the weld were taken according to GB / T 2650 standard. Three specimens were tested, and the average value was taken. The test results of the mechanical properties of the weld metal are shown in Table 5. The results show that the weld metal of the examples can achieve a balance between strength and toughness, while the comparative examples have problems with either excessive strength or insufficient toughness.

[0053] Table 5. Mechanical property test results of weld metals after argon-rich shielded welding in Examples 1-7 and Comparative Examples 1-3.

[0054]

[0055] Weld metal samples were taken from Examples 1-7 and Comparative Examples 1-3. Referring 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", a 0.01 mol / L NaHSO3 solution was used to simulate the industrial atmospheric environment. Accelerated corrosion tests were conducted on the Q450EWR1 base material and weld metal for 120 hours in a cyclic immersion accelerated corrosion test chamber. The relative corrosion rate (relative corrosion rate = |base material weight loss - weld metal weight loss / base material weight loss × 100%) was calculated to evaluate the atmospheric corrosion resistance of the base material and weld metal. The test results after 120 hours are shown in Table 6. The results showed that the weld metals of the examples all had a relative corrosion rate of less than 10% with the Q450EWR1 base material, meeting the standard requirements and achieving a match with the corrosion performance of the base material. In contrast, the relative corrosion rate of the welding wire in the comparative example was higher than 13%, indicating poor corrosion performance. Furthermore, the accelerated corrosion plates of Example 3 and Comparative Example 2 were observed after 48 hours and 72 hours, respectively. The plates of the examples showed higher uniformity of the rust layer on the surface, with no obvious corrosion pits. In contrast, the plates of the comparative example showed numerous obvious pits and poor uniformity, indicating significant uneven corrosion in the solution, which is detrimental to obtaining high corrosion resistance.

[0056] Table 6 shows the comparison of corrosion weight loss and base metal in the immersion test of weld metal after argon-rich shielded welding in Examples 1-7 and Comparative Examples 1-3.

[0057]

[0058] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A welding wire, characterized in that, The welding wire contains the following elements by weight percentage: C: 0-0.05, Si: 0.65-0.80, Mn: 1.20-1.50, Cr: 1.70-2.50, Ni: 1.50-2.00, Cu: 0-0.15, Mo: 0-0.1, Ti: 0.02-0.03, Ca: 0-0.05, Mg: 0-0.03, Y: 0.01-0.03, B: 0-0.001, O: ≤0.004, N: ≤0.006, with the balance being Fe and other unavoidable impurities; the welding wire contains at least three of Ti, Ca, Mg, Y, and B; the chemical composition, calculated by weight percentage, satisfies: 0.02≤α≤0.07, 0.04≤γ≤0.60, where: α = (Ti + 1 / 2 Ca + 1 / 2 Mg + 3 Y) / ( Si+Mn); γ=Ni+7Cu+15Mo-Cr-Si.

2. The welding wire according to claim 1, characterized in that, The welding wire has a diameter of 1.2 mm and a copper plating thickness of 0.19-0.22 μm on its surface.

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