Rare earth element-containing high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire and preparation method thereof

Abstract

The high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing the rare earth elements comprises a flux core and a welding skin, and the flux core is composed of, by mass, 18%-22% of Cr, 6%-8% of Mo, 3%-6.5% of Nb, 1%-2% of Ti, 0.5%-1% of Al, 0.8%-2% of Mn, 0.3%-0.8% of Si, 0.05%-0.1% of Ce, 0.05%-0.1% of Y and the balance Ni. The invention further discloses a preparation method and a welding method of the high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing the rare earth elements. According to the high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing the rare earth elements, the problems that an existing welding material is insufficient in endurance strength at the high temperature, high in thermal cycle crack sensitivity and weak in chloride ion stress corrosion resistance are solved; and collaborative optimization of ultrahigh-temperature structure stability, thermal cracking resistance and extreme environment corrosion resistance is realized.

Description

Technical Field

[0001] This invention belongs to the field of welding materials technology, and relates to a high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements. This invention also relates to the preparation method and welding method of the above-mentioned high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements. Background Technology

[0002] Currently, welding of special equipment operating in alternating ultra-high temperature (>950℃) and ultra-low temperature (<-50℃) environments (such as high-temperature components of steam turbines and deep geothermal drilling equipment) requires weld metals to possess both structural stability and mechanical continuity across extreme temperature ranges. Traditional high-alloy flux-cored welding wires are limited by a rigid nickel-niobium composition ratio (Ni≤50%, Nb≤4%), exposing structural defects in three dimensions: First, the high-temperature strengthening mechanism is singular; the molybdenum-tungsten system, which relies on solid solution strengthening, faces the risk of brittle precipitation of the Laves phase during long-term thermal exposure, while insufficient niobium content prevents the formation of a stable nanoscale coherent strengthening phase, resulting in a creep fracture life of less than 30% of the design requirement at 1000℃. Second, the adaptability to welding dissimilar materials is rigid; a fixed nickel content is difficult to adapt to the gradient connection between nickel-based alloys and high-strength duplex steels. The low-nickel side weld undergoes grain boundary selective corrosion in sulfur-containing media, while the high-nickel side is prone to interfacial peeling cracks due to the mismatch in thermal expansion coefficients.

[0003] Existing technologies attempt to compensate for performance gaps by adding precious elements such as tantalum and hafnium, but the following problems still exist: high-density active elements form non-equilibrium segregated clusters in the molten pool, which not only exacerbates the sensitivity of microcracks between multiple weld layers, but also causes a cliff-like decline in low-temperature toughness (impact energy fluctuation range of ±40% at -60℃). In particular, when the niobium content exceeds the critical value of 5%, conventional deoxidizers cannot suppress the grain boundary network distribution of niobium-oxygen-nitrogen composite inclusion chains, causing irreversible hydrogen-induced hysteresis cracking of thick-walled component welds in high-pressure hydrogen environments. Summary of the Invention

[0004] The purpose of this invention is to provide a high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements, which solves the problems of insufficient creep strength, high sensitivity to thermal cycling cracking, and weak resistance to chloride ion stress corrosion of existing welding materials at high temperatures. Through the synergistic effect of rare earth and high niobium, the invention achieves synergistic optimization of ultra-high temperature structural stability, thermal crack resistance, and corrosion resistance in extreme environments.

[0005] The second objective of this invention is to provide a method for preparing the above-mentioned high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements.

[0006] A third objective of this invention is to provide a welding method for the above-mentioned high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements.

[0007] The first technical solution adopted in this invention is a high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements, comprising a flux core and a welding sheath. The flux core is composed of the following components by mass percentage: chromium (Cr): 18-22%, molybdenum (Mo): 6-8%, niobium (Nb): 3-6.5%, titanium (Ti): 1-2%, aluminum (Al): 0.5-1%, manganese (Mn): 0.8-2%, silicon (Si): 0.3-0.8%, cerium (Ce): 0.05-0.1%, yttrium (Y): 0.05-0.1%, with the balance being nickel (Ni).

[0008] The invention is further characterized by: The solder sheet is made of Inconel 600 nickel-based alloy strip.

[0009] The powder filling rate of the core is 18wt%-25wt%, and the powder particle size of the core is not less than 100 mesh.

[0010] The second technical solution adopted in this invention is a method for preparing high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements, which is implemented according to the following steps: Step 1: Weigh the raw material powders according to their mass percentages; Step 2: Heat and keep warm the raw material powder weighed in Step 1; Step 3: Stir the raw material powder obtained in Step 2 until it is homogeneous; Step 4: Fill the U-shaped welding skin with the raw material powder obtained in Step 3, and close the welding skin with a mold to obtain the original welding wire; Step 5: The original welding wire obtained in Step 4 is processed into a high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements with the required diameter by a step-by-step diameter reduction method.

[0011] The second technical solution of the present invention is further characterized by: In step 1, the raw material powder has the following mass percentages: Cr: 18-22%, Mo: 6-8%, Nb: 3-6.5%, Ti: 1-2%, Al: 0.5-1%, Mn: 0.8-2%, Si: 0.3-0.8%, Ce: 0.05-0.1%, Y: 0.05-0.1%, with the balance being Ni. The powder particle size is not less than 100 mesh.

[0012] In step 2, the raw material powder obtained in step 1 is placed in an empty tube furnace and heated to 160℃~210℃, and kept at that temperature for 2-3 hours.

[0013] In step 3, the raw material powder obtained in step 2 is placed in a mixing flask and stirred in a V-type mixer for 20-40 minutes at a speed of 10-30 rpm.

[0014] In step 4, the solder skin is an Inconel 600 nickel-based alloy strip, and the powder filling rate of the flux core is 18wt%-25wt%.

[0015] The third technical solution adopted in this invention is a welding method for high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements. Welding is performed using this high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements via automatic TIG welding, specifically implemented according to the following steps: Step 1: Set the parameters for the automatic TIG welding equipment; Step 2: Select a tungsten electrode of appropriate diameter and a high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements, and adjust the shielding gas according to the welding current and the material of the workpiece. Step 3: Weld the workpiece under a protective gas atmosphere; Step 4: Clean the surface of the weldment after welding is completed.

[0016] The third technical solution of the present invention is further characterized by: In step 1, the voltage is 10V~14V, the current is 120A~180A, and the wire extension is 8mm~122mm; in step 2, the shielding gas is argon, and the flow rate is 12L / min~18L / min; in step 3, the welding speed is 35-40cm / min.

[0017] The beneficial effects of this invention are: (1) The present invention provides a high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements, which has a short preparation cycle, high production efficiency, and can be mass-produced. (2) The high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements provided by this invention has good processability, and the weld formation is good, dense and smooth. As a key area of ​​pressure-bearing equipment in a high-temperature and high-pressure corrosive environment, the weld has a creep strength of over 180 MPa at 1200℃ and a chloride ion pitting potential of ≥0.85V, which is 2.8-3.5 times that of traditional nickel-based welding wires. Moreover, it has no tendency to reheat cracking under thermal cycling conditions, and its comprehensive performance is significantly better than that of similar high-temperature alloy base materials. At the same time, special alloy components are added to the flux-cored welding wire. These components can form hard carbides or other hard phases during the welding process, which significantly improves the strength and wear resistance of the weld layer.

[0018] (3) The present invention provides a welding method for high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements. Using high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements as raw material, the flux core is uniform and the arc is stable during the welding process, which can greatly improve the wear resistance and service life of the weld. The weld is beautiful and basically without collapse. Attached Figure Description

[0019] Figure 1This is a microstructure diagram of Example 6 of the high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements according to the present invention. Detailed Implementation

[0020] The following detailed description is provided in conjunction with specific implementation methods.

[0021] High-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements, including flux core and welding skin. The flux core is composed of the following components by mass percentage: Cr: 18-22%, Mo: 6-8%, Nb: 3-6.5%, Ti: 1-2%, Al: 0.5-1%, Mn: 0.8-2%, Si: 0.3-0.8%, Ce: 0.05-0.1%, Y: 0.05-0.1%, with the balance being Ni.

[0022] The solder sheet is made of Inconel 600 nickel-based alloy strip.

[0023] The powder filling rate of the core is 18wt%-25wt%, and the powder particle size of the core is not less than 100 mesh.

[0024] The functions and roles of each component in this welding wire are as follows: Ni, as an austenitic matrix framework element, broadens the high-temperature microstructure stability window by stabilizing the γ-phase field. Its high solid solution properties significantly enhance the low-temperature toughness reserve of weld metal, while simultaneously ensuring microstructural integrity under long-term high-temperature service by suppressing the precipitation kinetics of harmful intermetallic compounds. In dissimilar steel welding scenarios, a nickel content gradient design can effectively coordinate the mismatch in thermal expansion coefficients between the base metal and the weld, eliminating the tendency for interfacial delamination.

[0025] Cr: It is the core builder of the passivation film, forming a dense chromium trioxide (Cr2O3) protective layer in oxidizing media. Its key role is to block the chloride ion penetration path, significantly improving resistance to pitting corrosion and stress corrosion cracking. Under high-temperature conditions, chromium prevents the precipitation of brittle phases along the grain boundaries by hysteresis σ-phase nucleation barriers, thus maintaining the creep strength of the weld.

[0026] Mo plays a multi-scale protective role in welding metallurgy. At the atomic level, its strong carbide formation tendency refines the distribution of grain boundary precipitates, enhancing short-term high-temperature strength. At the macroscopic level, molybdenum significantly improves the matrix's creep resistance through solid solution strengthening. Its core breakthrough lies in constructing a "reducing medium corrosion-resistant fortress," that is, preferentially forming a molybdenum-oxygen cluster passivation layer in acidic environments to block hydrogen ion diffusion paths, which is particularly suitable for welding oil and gas pipelines containing hydrogen sulfide. In multi-layer welding scenarios, molybdenum ensures the safety of post-weld heat treatment of thick-walled components by suppressing plasticity loss in the reheat crack-sensitive temperature zone. Its synergistic effect with niobium can optimize the carbide precipitation sequence, preventing excessive coarsening of the M6C phase during high-temperature service.

[0027] Niobium (Nb) is a revolutionary element for high-temperature strength and structural stability. As a strong carbide and nitride forming agent, niobium achieves both grain boundary pinning and dendrite refinement at the solidification front of the molten pool by generating nanoscale MC-type carbides (mainly niobium carbide (NbC)). Its core value lies in blocking the high-temperature grain coarsening pathway, significantly improving the weld's creep life. During the welding thermal cycle, niobium induces the formation of a coherent strengthening network by reducing the solid solubility product of the γ″ phase (Ni3Nb), thus doubling the stress fracture resistance in the sensitive temperature range of 650-850℃. For welding niobium-containing steels, its unique niobium partitioning effect can suppress liquefaction cracks in the heat-affected zone and eliminate porosity defects by fixing residual nitrogen. High niobium content (>5%) requires innovative deoxidation technology to avoid the risk of inclusion embrittlement.

[0028] Ti: A precise regulator of molten pool reaction kinetics. As a strong deoxidizer, titanium preferentially combines with active oxygen in the high-temperature region of the electric arc (>3000K) to form low-density titanium dioxide (TiO2), whose unique flotation properties promote effective slag separation. Its metallurgical essence lies in oxygen potential gradient management, which, by establishing a dynamic balance between titanium and oxidation potentials, suppresses secondary oxidation of the molten pool and reduces porosity. During the droplet transition stage, titanium optimizes the droplet morphology from jet flow to droplet transition by altering the surface tension gradient of the liquid metal, significantly reducing the spatter rate. In the later stages of solidification, titanium combines with nitrogen to form stable titanium nitride (TiN) particles, becoming a heterogeneous austenitic nucleation substrate, achieving finer weld microstructure. Its content must avoid the formation of coarse titanium oxides, which would lead to a loss of toughness.

[0029] Al is a key synergist in deoxidation systems and oxide film engineering. When combined with titanium, aluminum achieves deep deoxidation of the molten pool while ensuring the spheroidization and dispersion of inclusions by generating submicron-sized alumina-magnesia (Al2O3-MgO) spinel composite deoxidation products. Its core innovation lies in the optimization of oxide film structure. In high-temperature service environments, aluminum participates in the construction of a ferrochrome-alumina (FeCr2O4-Al2O3) gradient spinel film, significantly improving anti-stripping ability and self-healing efficiency. In welding metallurgy, aluminum improves the wetting behavior of the fusion line and eliminates incomplete fusion defects by reducing the solid-liquid interface energy of the molten pool. Its content needs to be strictly controlled to prevent low-temperature toughness degradation caused by aluminum oxide agglomeration, and it improves grain boundary purity through electronic interactions with rare earth elements.

[0030] Manganese (Mn) plays a dual role in controlling sulfur segregation and optimizing the process. As a deoxidizer, manganese promotes slag polymerization and flotation by forming a low-melting-point manganese oxide-silica (MnO-SiO2) composite oxide. Its core value lies in the morphological reconstruction of sulfur, transforming grain boundary sulfides (FeS) into spherical manganese sulfide (MnS) inclusions, effectively blocking the propagation path of sulfur-induced cracks. At the welding process level, manganese enhances the strength reserve of weld metal through solid solution strengthening and optimizes weld spreadability and penetration profile by adjusting the viscosity and surface tension coefficient of the molten pool. For high-nickel alloy welding, manganese can suppress temper brittleness and ensure the stability of impact toughness during post-weld heat treatment. Its content window needs to balance desulfurization efficiency with the risk of segregation-induced thermal cracking.

[0031] Si: A comprehensive regulator of the physicochemical behavior of the molten pool. As an auxiliary deoxidizing element, silicon promotes effective slag separation by lowering the melting point of deoxidation products. Its core metallurgical function lies in rheological optimization, reducing the viscosity of liquid metal and increasing surface tension, triggering the Marangoni convection reversal effect, and eliminating undercut and hump weld defects. During solidification, silicon refines the microstructure and reduces compositional segregation by inhibiting the lateral growth rate of austenite dendrites. Its unique advantage lies in improving the surface finish of the weld and reducing subsequent processing costs. However, excessive silicon will lead to loss of low-temperature toughness and silicate inclusion aggregation, requiring fine control through rare earth modification treatment.

[0032] Ce: A strategic element for grain boundary engineering and inclusion morphology control. Its core breakthrough lies in the grain boundary purification effect, which involves selectively adsorbing impurities such as sulfur and phosphorus to form high-melting-point rare earth compounds, blocking the precipitation channels of embrittled phases at grain boundaries. At the solidification front, cerium promotes dendrite refinement and equiaxed crystal transformation by reducing solid-liquid interfacial energy, significantly improving resistance to solidification cracks. For deoxidation products, cerium transforms oxides / sulfides from angular to spherical shapes, eliminating stress concentration sources. In corrosive environments, cerium extends the service life of components by optimizing passivation film adhesion and self-healing kinetics. Its trace addition (0.05-0.1%) requires precise control to prevent abnormal increases in molten pool viscosity.

[0033] Y: Focusing on long-term protective engineering in extreme environments. Its core value lies in the oxide film pinning effect, namely, by forming a yttrium aluminum oxide (Y-Al-O) nano-transition layer at the oxide film / substrate interface, significantly improving oxide film adhesion and resistance to thermal shock spalling. In high-temperature creep conditions, yttrium, by refining the distribution of carbides at grain boundaries, blocks the along-grain propagation path of creep cracks. Its deep metallurgical mechanism includes purifying grain boundary micro-regions, inhibiting the segregation of harmful elements, and increasing the recrystallization temperature by approximately 100°C. In chlorine-containing media, yttrium significantly slows down the stress corrosion cracking rate by altering the pitting corrosion initiation mechanism (from penetrating to shallow pitting). Its synergistic effect with cerium can construct a multi-level protection system.

[0034] The preparation method of high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements is implemented according to the following steps: Step 1: Weigh the raw material powders according to their mass percentages. The raw material powder has the following mass percentages: Cr: 18-22%, Mo: 6-8%, Nb: 3-6.5%, Ti: 1-2%, Al: 0.5-1%, Mn: 0.8-2%, Si: 0.3-0.8%, Ce: 0.05-0.1%, Y: 0.05-0.1%, with the balance being Ni. The powder particle size is not less than 100 mesh.

[0035] Step 2: Heat and keep warm the raw material powder weighed in Step 1. The raw material powder obtained in step 1 is placed in an empty tube furnace and heated to 160℃~210℃, and kept at that temperature for 2-3 hours.

[0036] Step 3: Stir the raw material powder obtained in Step 2 until homogeneous. Place the raw material powder obtained in step 2 into a mixing flask and mix it in a V-type mixer for 20-40 minutes at a speed of 10-30 rpm.

[0037] Step 4: Fill the U-shaped welding skin with the raw material powder obtained in Step 3, and close the welding skin with a mold to obtain the original welding wire. The welding skin is an Inconel 600 nickel-based alloy strip, and the powder filling rate of the flux core is 18wt%-25wt%.

[0038] Step 5: The original welding wire obtained in Step 4 is processed into a high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements with the required diameter by a step-by-step diameter reduction method.

[0039] When the required diameter is 1.20mm, the Inconel 600 nickel-based alloy strip with a solder pad width of 7mm and a thickness of 0.3mm is selected.

[0040] The welding method for high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements involves welding using an automated TIG welding system, specifically implemented according to the following steps: Step 1: Set the parameters of the automatic TIG welding equipment: voltage 10V~14V, current 120A~180A, and wire extension 8mm~122mm.

[0041] Step 2: Select a tungsten electrode of appropriate diameter and a high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements, based on the welding current and the material of the workpiece. Adjust the shielding gas, which is argon, with a flow rate of 12L / min to 18L / min.

[0042] Step 3: Weld the workpiece under a protective gas atmosphere. During the welding process, keep the angle of the welding torch and the welding speed stable. To ensure that the argon gas can better protect the molten pool, the center line of the tungsten electrode should be perpendicular to the surface of the workpiece at the welding point. Depending on the thickness of the plate, the welding speed is 35-40 cm / min.

[0043] Step 4: Clean the surface of the weldment after welding is completed.

[0044] Example 1 The preparation method of high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements is implemented according to the following steps: Step 1: Weigh the raw material powders according to their mass percentages. The raw material powder has the following mass percentages: Cr: 18%, Mo: 6%, Nb: 3%, Ti: 1-2%, Al: 0.6%, Mn: 0.9%, Si: 0.3%, Ce: 0.05%, Y: 0.05%, with the balance being Ni. The particle size of the core powder is not less than 100 mesh.

[0045] Step 2: Heat and keep warm the raw material powder weighed in Step 1. The raw material powder obtained in step 1 is placed in an empty tube furnace and heated to 160℃~210℃, and kept at that temperature for 2-3 hours.

[0046] Step 3: Stir the raw material powder obtained in Step 2 until homogeneous. Place the raw material powder obtained in step 2 into a mixing flask and mix it in a V-type mixer for 20-40 minutes at a speed of 10-30 rpm until it is uniformly mixed.

[0047] Step 4: Fill the U-shaped welding skin with the raw material powder obtained in Step 3, and close the welding skin with a mold to obtain the original welding wire. The powder filling rate of the flux core is 18wt%, and the welding skin is Inconel 600 nickel-based alloy strip with a width of 7mm and a thickness of 0.3mm.

[0048] Step 5: The original welding wire obtained in Step 4 is processed into a 1.2mm high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements by gradually reducing the diameter of the wire through a closed forming roll.

[0049] The welding method for high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements involves welding using an automated TIG welding system, specifically implemented according to the following steps: Step 1: Set the parameters of the automatic TIG welding equipment: voltage 10V, current 120A, and wire extension 8mm.

[0050] Step 2: Select a tungsten electrode of appropriate diameter and a high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements, based on the welding current and the material of the workpiece. Adjust the shielding gas, which is argon, with a flow rate of 12L / min to 18L / min.

[0051] Step 3: Weld the workpiece under a protective gas. During the welding process, keep the angle of the welding torch and the welding speed stable. In order to make the argon gas better protect the molten pool, the center line of the tungsten electrode is perpendicular to the surface of the workpiece at the welding point, the angle of the welding torch is 90°, and the welding speed is 35cm / min.

[0052] Step 4: Clean the surface of the weldment after welding is completed.

[0053] The gas turbine combustor component welded using rare-earth high-niobium nickel-based flux-cored wire prepared in this embodiment exhibits excellent process adaptability in automated TIG welding. The arc combustion is stable and drift-free, and the molten pool forms a smooth liquid-solid interface due to the surface tension regulation effect of rare-earth elements. The weld formation is uniform and smooth, completely eliminating defects such as undercut and lack of fusion. X-ray inspection shows a porosity of less than 0.35%, and no solidification cracks were found in the oblique Y-groove test. The deposited metal acquires a unique dual-phase strengthening microstructure: niobium carbides and rare-earth oxides synergistically pin grain boundaries, resulting in a room temperature tensile strength of 830 MPa while maintaining a high elongation of 22%. In a 650°C high-temperature creep rupture test, its fracture life is 2.1 times that of conventional nickel-based welding materials. This is attributed to the high niobium content effectively inhibiting grain boundary slip and hindering MnO2. 23 C6 carbide chains precipitate. Meets usage requirements.

[0054] Example 2 The preparation method of high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements is implemented according to the following steps: Step 1: Weigh the raw material powders according to their mass percentages. The raw material powder has the following mass percentages: Cr: 19.3%, Mo: 6.7%, Nb: 3.5%, Ti: 1.3%, Al: 0.65%, Mn: 0.93%, Si: 0.46%, Ce: 0.06%, Y: 0.06%, with the balance being Ni. The particle size of the core powder is not less than 100 mesh.

[0055] Step 2: Heat and keep warm the raw material powder weighed in Step 1. The raw material powder obtained in step 1 is placed in an empty tube furnace and heated to 160℃~210℃, and kept at that temperature for 2-3 hours.

[0056] Step 3: Stir the raw material powder obtained in Step 2 until homogeneous. Place the raw material powder obtained in step 2 into a mixing flask and mix it in a V-type mixer for 20-40 minutes at a speed of 10-30 rpm until it is uniformly mixed.

[0057] Step 4: Fill the U-shaped welding skin with the raw material powder obtained in Step 3, and close the welding skin with a mold to obtain the original welding wire. The powder filling rate of the flux core is 19wt%, and the welding skin is an Inconel 600 nickel-based alloy strip with a width of 7mm and a thickness of 0.3mm.

[0058] Step 5: The original welding wire obtained in Step 4 is processed into a 1.2mm high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements by gradually reducing the diameter of the wire through a closed forming roll.

[0059] The welding method for high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements involves welding using an automated TIG welding system, specifically implemented according to the following steps: Step 1: Set the parameters of the automatic TIG welding equipment: voltage 11V, current 130A, and wire extension 9mm.

[0060] Step 2: Select a tungsten electrode of appropriate diameter and a high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements, based on the welding current and the material of the workpiece. Adjust the shielding gas, which is argon, with a flow rate of 12L / min to 18L / min.

[0061] Step 3: Weld the workpiece under a protective gas. During the welding process, keep the angle of the welding torch and the welding speed stable. In order to make the argon gas better protect the molten pool, the center line of the tungsten electrode is perpendicular to the surface of the workpiece at the welding point, the angle of the welding torch is 90°, and the welding speed is 36cm / min.

[0062] Step 4: Clean the surface of the weldment after welding is completed.

[0063] The gas turbine combustor component welded using the rare-earth high-niobium nickel-based flux-cored wire prepared in this embodiment exhibits excellent process adaptability in automated TIG welding. The arc combustion is stable and drift-free, and the molten pool forms a smooth liquid-solid interface due to the surface tension regulation effect of rare-earth elements. The weld formation is uniform and smooth, completely eliminating defects such as undercut and lack of fusion. X-ray inspection shows a porosity of less than 0.32%, and no solidification cracks were found in the oblique Y-groove test. The deposited metal acquires a unique dual-phase strengthening microstructure: niobium carbides and rare-earth oxides synergistically pin grain boundaries, resulting in a room temperature tensile strength of 842 MPa while maintaining a high elongation of 22%. In a 650℃ high-temperature creep rupture test, its fracture life is 2.13 times that of conventional nickel-based welding materials. This is attributed to the high niobium content effectively inhibiting grain boundary slip and hindering MnO2. 23 C6 carbide chains precipitate. Meets usage requirements.

[0064] Example 3 The preparation method of high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements is implemented according to the following steps: Step 1: Weigh the raw material powders according to their mass percentages. The raw material powder has the following mass percentages: Cr: 19.6%, Mo: 7.1%, Nb: 4.68%, Ti: 1.45%, Al: 0.66%, Mn: 1.02%, Si: 0.44%, Ce: 0.065%, Y: 0.065%, with the balance being Ni. The particle size of the core powder is not less than 100 mesh.

[0065] Step 2: Heat and keep warm the raw material powder weighed in Step 1. The raw material powder obtained in step 1 is placed in an empty tube furnace and heated to 160℃~210℃, and kept at that temperature for 2-3 hours.

[0066] Step 3: Stir the raw material powder obtained in Step 2 until homogeneous. Place the raw material powder obtained in step 2 into a mixing flask and mix it in a V-type mixer for 20-40 minutes at a speed of 10-30 rpm until it is uniformly mixed.

[0067] Step 4: Fill the U-shaped welding skin with the raw material powder obtained in Step 3, and close the welding skin with a mold to obtain the original welding wire. The powder filling rate of the flux core is 21wt%, and the welding skin is an Inconel 600 nickel-based alloy strip with a width of 7mm and a thickness of 0.3mm.

[0068] Step 5: The original welding wire obtained in Step 4 is processed into a 1.2mm high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements by gradually reducing the diameter of the wire through a closed forming roll.

[0069] The welding method for high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements involves welding using an automated TIG welding system, specifically implemented according to the following steps: Step 1: Set the parameters of the automatic TIG welding equipment: voltage 12V, current 138A, and wire extension 9mm.

[0070] Step 2: Select a tungsten electrode of appropriate diameter and a high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements, based on the welding current and the material of the workpiece. Adjust the shielding gas, which is argon, with a flow rate of 12L / min to 18L / min.

[0071] Step 3: Weld the workpiece under a protective gas. During the welding process, keep the angle of the welding torch and the welding speed stable. In order to make the argon gas better protect the molten pool, the center line of the tungsten electrode is perpendicular to the surface of the workpiece at the welding point, the angle of the welding torch is 90°, and the welding speed is 37cm / min.

[0072] Step 4: Clean the surface of the weldment after welding is completed.

[0073] The gas turbine combustor component prepared in this embodiment, welded using a rare-earth-containing high-niobium nickel-based flux-cored wire, exhibits excellent process adaptability in automated TIG welding. The arc combustion is stable and drift-free, and the molten pool forms a smooth liquid-solid interface due to the surface tension regulation effect of rare-earth elements. The weld formation is uniform and smooth, completely eliminating defects such as undercut and lack of fusion. X-ray inspection shows a porosity of less than 0.34%, and no solidification cracks were found in the oblique Y-groove test. The deposited metal acquires a unique dual-phase strengthening microstructure: niobium carbides and rare-earth oxides synergistically pin grain boundaries, enabling a room temperature tensile strength exceeding 856 MPa while maintaining a high elongation of 22%. In a 650°C high-temperature creep rupture test, its fracture life is 2.1 times that of conventional nickel-based welding materials. This is due to the high niobium content effectively inhibiting grain boundary slip and hindering M... 23 C6 carbide chains precipitate. Meets usage requirements.

[0074] Example 4 The preparation method of high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements is implemented according to the following steps: Step 1: Weigh the raw material powders according to their mass percentages. The raw material powder has the following mass percentages: Cr: 20.4%, Mo: 7.2%, Nb: 4.8%, Ti: 1.69%, Al: 0.73%, Mn: 1.28%, Si: 0.59%, Ce: 0.074%, Y: 0.074%, with the balance being Ni. The particle size of the core powder is not less than 100 mesh.

[0075] Step 2: Heat and keep warm the raw material powder weighed in Step 1. The raw material powder obtained in step 1 is placed in an empty tube furnace and heated to 160℃~210℃, and kept at that temperature for 2-3 hours.

[0076] Step 3: Stir the raw material powder obtained in Step 2 until homogeneous. Place the raw material powder obtained in step 2 into a mixing flask and mix it in a V-type mixer for 20-40 minutes at a speed of 10-30 rpm until it is uniformly mixed.

[0077] Step 4: Fill the U-shaped welding skin with the raw material powder obtained in Step 3, and close the welding skin with a mold to obtain the original welding wire. The powder filling rate of the flux core is 23wt%, and the welding skin is Inconel 600 nickel-based alloy strip with a width of 7mm and a thickness of 0.3mm.

[0078] Step 5: The original welding wire obtained in Step 4 is processed into a 1.2mm high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements by gradually reducing the diameter of the wire through a closed forming roll.

[0079] The welding method for high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements involves welding using an automated TIG welding system, specifically implemented according to the following steps: Step 1: Set the parameters of the automatic TIG welding equipment: voltage 13V, current 156A, and wire extension 10mm.

[0080] Step 2: Select a tungsten electrode of appropriate diameter and a high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements, based on the welding current and the material of the workpiece. Adjust the shielding gas, which is argon, with a flow rate of 12L / min to 18L / min.

[0081] Step 3: Weld the workpiece under a protective gas. During the welding process, keep the angle of the welding torch and the welding speed stable. In order to make the argon gas better protect the molten pool, the center line of the tungsten electrode is perpendicular to the surface of the workpiece at the welding point, the angle of the welding torch is 90°, and the welding speed is 37cm / min.

[0082] Step 4: Clean the surface of the weldment after welding is completed.

[0083] The gas turbine combustor component prepared in this embodiment and welded using this rare-earth-containing high-niobium nickel-based flux-cored wire exhibits excellent process adaptability in automated TIG welding. The arc combustion is stable and drift-free, and the molten pool forms a smooth liquid-solid interface due to the surface tension regulation effect of rare-earth elements. The weld formation is uniform and smooth, completely eliminating defects such as undercut and lack of fusion. X-ray inspection shows a porosity of less than 0.39%, and no solidification cracks were found in the oblique Y-groove test. The deposited metal acquires a unique dual-phase strengthening microstructure: niobium carbides and rare-earth oxides synergistically pin grain boundaries, enabling a room temperature tensile strength exceeding 843 MPa while maintaining a high elongation of 22%. In a 650℃ high-temperature creep rupture test, its fracture life is 2.14 times that of conventional nickel-based welding materials. This is due to the high niobium content effectively inhibiting grain boundary slip and hindering M... 23 C6 carbide chains precipitate. Meets usage requirements.

[0084] Example 5 The preparation method of high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements is implemented according to the following steps: Step 1: Weigh the raw material powders according to their mass percentages. The raw material powder has the following mass percentages: Cr: 21%, Mo: 7.4%, Nb: 5.5%, Ti: 1.9%, Al: 0.8%, Mn: 1.5%, Si: 0.6%, Ce: 0.084%, Y: 0.084%, with the balance being Ni. The particle size of the core powder is not less than 100 mesh.

[0085] Step 2: Heat and keep warm the raw material powder weighed in Step 1. The raw material powder obtained in step 1 is placed in an empty tube furnace and heated to 160℃~210℃, and kept at that temperature for 2-3 hours.

[0086] Step 3: Stir the raw material powder obtained in Step 2 until homogeneous. Place the raw material powder obtained in step 2 into a mixing flask and mix it in a V-type mixer for 20-40 minutes at a speed of 10-30 rpm until it is uniformly mixed.

[0087] Step 4: Fill the U-shaped welding skin with the raw material powder obtained in Step 3, and close the welding skin with a mold to obtain the original welding wire. The powder filling rate of the flux core is 24wt%, and the welding skin is an Inconel 600 nickel-based alloy strip with a width of 7mm and a thickness of 0.3mm.

[0088] Step 5: The original welding wire obtained in Step 4 is processed into a 1.2mm high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements by gradually reducing the diameter of the wire through a closed forming roll.

[0089] The welding method for high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements involves welding using an automated TIG welding system, specifically implemented according to the following steps: Step 1: Set the parameters of the automatic TIG welding equipment: voltage 13V, current 150A, and wire extension 11mm.

[0090] Step 2: Select a tungsten electrode of appropriate diameter and a high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements, based on the welding current and the material of the workpiece. Adjust the shielding gas, which is argon, with a flow rate of 12L / min to 18L / min.

[0091] Step 3: Weld the workpiece under a protective gas. During the welding process, keep the angle of the welding torch and the welding speed stable. In order to make the argon gas better protect the molten pool, the center line of the tungsten electrode is perpendicular to the surface of the workpiece at the welding point, the angle of the welding torch is 90°, and the welding speed is 39cm / min.

[0092] Step 4: Clean the surface of the weldment after welding is completed.

[0093] The gas turbine combustor component prepared in this embodiment, welded using a rare-earth-containing high-niobium nickel-based flux-cored wire, exhibits excellent process adaptability in automated TIG welding—stable arc combustion without drift, a smooth liquid-solid interface formed in the molten pool due to the surface tension regulation effect of rare-earth elements, and uniform and smooth weld formation, completely eliminating defects such as undercut and lack of fusion. X-ray inspection showed a porosity of less than 0.37%, and no solidification cracks were found in the oblique Y-groove test. The deposited metal acquires a unique dual-phase strengthening microstructure: niobium carbides and rare-earth oxides synergistically pin grain boundaries, enabling a room temperature tensile strength exceeding 869 MPa while maintaining a high elongation of 22%. In a high-temperature creep rupture test at 650℃, its fracture life is 2.15 times that of conventional nickel-based welding materials, which is attributed to the high niobium content effectively inhibiting grain boundary slip and hindering M 23 C6 carbide chains precipitate. Meets usage requirements.

[0094] Example 6 The preparation method of high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements is implemented according to the following steps: Step 1: Weigh the raw material powders according to their mass percentages. The raw material powder has the following mass percentages: Cr: 22%, Mo: 8%, Nb: 6.5%, Ti: 2%, Al: 1%, Mn: 2%, Si: 0.8%, Ce: 0.1%, Y: 0.1%, with the balance being Ni. The particle size of the core powder is not less than 100 mesh.

[0095] Step 2: Heat and keep warm the raw material powder weighed in Step 1. The raw material powder obtained in step 1 is placed in an empty tube furnace and heated to 160℃~210℃, and kept at that temperature for 2-3 hours.

[0096] Step 3: Stir the raw material powder obtained in Step 2 until homogeneous. Place the raw material powder obtained in step 2 into a mixing flask and mix it in a V-type mixer for 20-40 minutes at a speed of 10-30 rpm until it is uniformly mixed.

[0097] Step 4: Fill the U-shaped welding skin with the raw material powder obtained in Step 3, and close the welding skin with a mold to obtain the original welding wire. The powder filling rate of the flux core is 25wt%, and the welding skin is Inconel 600 nickel-based alloy strip with a width of 7mm and a thickness of 0.3mm.

[0098] Step 5: The original welding wire obtained in Step 4 is processed into a 1.2mm high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements by gradually reducing the diameter of the wire through a closed forming roll.

[0099] The welding method for high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements involves welding using an automated TIG welding system, specifically implemented according to the following steps: Step 1: Set the parameters of the automatic TIG welding equipment: voltage 14V, current 160A, and wire extension 14mm.

[0100] Step 2: Select a tungsten electrode of appropriate diameter and a high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements, based on the welding current and the material of the workpiece. Adjust the shielding gas, which is argon, with a flow rate of 12L / min to 18L / min.

[0101] Step 3: Weld the workpiece under a protective gas. During the welding process, keep the angle of the welding torch and the welding speed stable. In order to make the argon gas better protect the molten pool, the center line of the tungsten electrode is perpendicular to the surface of the workpiece at the welding point, the angle of the welding torch is 90°, and the welding speed is 40cm / min.

[0102] Step 4: Clean the surface of the weldment after welding is completed.

[0103] The gas turbine combustor component prepared in this embodiment, welded using a rare-earth-containing high-niobium nickel-based flux-cored wire, exhibits excellent process adaptability in automated TIG welding—stable arc combustion without drift, a smooth liquid-solid interface formed in the molten pool due to the surface tension regulation effect of rare-earth elements, and uniform and smooth weld formation, completely eliminating defects such as undercut and lack of fusion. X-ray inspection showed a porosity of less than 0.3%, and no solidification cracks were found in the oblique Y-groove test. The deposited metal acquires a unique dual-phase strengthening microstructure: niobium carbides and rare-earth oxides synergistically pin grain boundaries, enabling a room temperature tensile strength exceeding 874 MPa while maintaining a high elongation of 22%. In a high-temperature creep rupture test at 650℃, its fracture life is 2.1 times that of conventional nickel-based welding materials, which is attributed to the high niobium content effectively inhibiting grain boundary slip and hindering M 23 The C6 carbide chains precipitate out, which meets the usage requirements.

[0104] like Figure 1 As shown, the metal powder core wire prepared according to this embodiment clearly displays the microstructure of its weld. The γ-austenite matrix is ​​dispersed with 80-150nm of (Ni,Cr)3Nb coherent strengthening phase, which significantly improves the high-temperature strength at 760℃ by pinning dislocations. The original austenite grain boundaries are continuously coated with cerium dioxide-yttrium oxide (CeO2-Y2O3) rare earth oxides, forming a chloride ion penetration barrier. After 15,000 hours of operation verification, the chromium-niobium-rare earth gradient oxide film (Cr2O3 / Nb2O5 / YCrO3) on the weld surface remains intact under the scouring of high-speed steam at 120m / s, and there are no signs of σ phase precipitation in the heat-affected zone. The maintenance cycle is extended to 24,000 hours.

Claims

1. A high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements, characterized in that, It includes a flux core and a solder coating. The flux core is composed of the following components by mass percentage: Cr: 18-22%, Mo: 6-8%, Nb: 3-6.5%, Ti: 1-2%, Al: 0.5-1%, Mn: 0.8-2%, Si: 0.3-0.8%, Ce: 0.05-0.1%, Y: 0.05-0.1%, with the balance being Ni.

2. The high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements according to claim 1, characterized in that, The solder sheet is an Inconel 600 nickel-based alloy strip.

3. The high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements according to claim 1, characterized in that, The powder filling rate of the core is 18wt%-25wt%, and the powder particle size of the core is not less than 100 mesh.

4. A method for preparing high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements, characterized in that, The specific steps are as follows: Step 1: Weigh the raw material powders according to their mass percentages; Step 2: Heat and keep warm the raw material powder weighed in Step 1; Step 3: Stir the raw material powder obtained in Step 2 until it is homogeneous; Step 4: Fill the U-shaped welding skin with the raw material powder obtained in Step 3, and close the welding skin with a mold to obtain the original welding wire; Step 5: The original welding wire obtained in Step 4 is processed into a high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements with the required diameter by a step-by-step diameter reduction method.

5. The method for preparing the high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements according to claim 4, characterized in that, In step 1, the raw material powder has the following mass percentages: Cr: 18-22%, Mo: 6-8%, Nb: 3-6.5%, Ti: 1-2%, Al: 0.5-1%, Mn: 0.8-2%, Si: 0.3-0.8%, Ce: 0.05-0.1%, Y: 0.05-0.1%, with the balance being Ni, and the powder particle size is not less than 100 mesh.

6. The method for preparing the high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements according to claim 5, characterized in that, In step 2, the raw material powder obtained in step 1 is placed in an empty tube furnace and heated to 160℃~210℃, and kept at that temperature for 2-3 hours.

7. The method for preparing the high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements according to claim 5, characterized in that, In step 3, the raw material powder obtained in step 2 is placed in a mixing bottle and stirred in a V-type mixer for 20-40 minutes at a speed of 10-30 rpm.

8. The method for preparing the high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements according to claim 5, characterized in that, In step 4, the solder sheet is an Inconel 600 nickel-based alloy strip, and the powder filling rate of the flux core is 18wt%-25wt%.

9. A welding method for high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wire containing rare earth elements, characterized in that, Welding is performed using any of the rare earth element-containing high-niobium nickel-based high-temperature corrosion-resistant flux-cored welding wires as described in claims 1-3 via automated TIG welding, specifically following these steps: Step 1: Set the parameters for the automatic TIG welding equipment; Step 2: Select a tungsten electrode of appropriate diameter and a high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements, and adjust the shielding gas according to the welding current and the material of the workpiece. Step 3: Weld the workpiece under a protective gas atmosphere; Step 4: Clean the surface of the weldment after welding is completed.

10. The welding method of the high-niobium nickel-based high-temperature corrosion-resistant flux-cored wire containing rare earth elements according to claim 9, characterized in that, In step 1, the voltage is 10V~14V, the current is 120A~180A, and the wire extension is 8mm~122mm; in step 2, the shielding gas is argon, and the flow rate is 12L / min~18L / min; in step 3, the welding speed is 35-40cm / min.

Images