Co-Cr-W high-temperature alloy welding wire and preparation method thereof

Abstract

The invention relates to a Co-Cr-W high-temperature alloy welding wire and a preparation method thereof, belongs to the technical field of high-temperature alloy materials and welding, and solves one of the problems that an existing Co-Cr-W welding wire is poor in structure uniformity, limited in welding manufacturability, low in size precision and low in abrasion resistance. Comprising the steps that raw materials are smelted and cast into an electrode through vacuum induction smelting according to ingredients for preparing the welding wire; carrying out remelting and atomization powder preparation on the electrode; the gas atomization powder is screened, and powder with the preset particle size is obtained; the screened powder is loaded into a sheath for degassing treatment, and vacuumizing and sealing packaging are carried out; carrying out hot isostatic pressing treatment on the packaged sheath; the ingot blank is heated and bloomed, and a bar is obtained; the bar is heated and subjected to finish rolling, and a first wire is obtained; annealing the first wire rod, air-cooling, straightening and polishing to obtain a second wire rod; lubricating the second wire rod with aquadag, heating and drawing to obtain a third wire rod; and the third wire is polished to the preset diameter, and a welding wire finished product is obtained.

Description

Technical Field

[0001] This invention relates to the field of high-temperature alloy materials and welding technology, and in particular to a Co-Cr-W high-temperature alloy welding wire and its preparation method. Background Technology

[0002] In aero-engines and industrial gas turbines, the blade crown interlocking structure of high-pressure and low-pressure turbine blades is subjected to complex conditions such as vibration friction, high-temperature oxidation, and gas erosion over long periods. A wear-resistant alloy layer must be welded over this structure to ensure the component's service safety. The core protection requirement for this structure is to reduce wear caused by high-frequency collisions between adjacent blade crowns and to prevent blade resonance failure due to increased clearance. Therefore, the wear-resistant layer must simultaneously possess excellent room-temperature weldability, high-temperature wear resistance, and oxidation stability to meet the long service life requirements of turbine components.

[0003] Currently, cobalt-based wear-resistant alloy welding wire is widely used for the surfacing of wear-resistant layers on turbine blade serrated crowns. This type of welding wire is mainly prepared through a casting + wire cutting process. However, this process has the following technical limitations: First, the cast structure is prone to dendritic segregation, with W element accumulating between dendrites to form coarse strengthening phases, resulting in uneven wire microstructure and properties. Second, the cast blank has poor plasticity, making subsequent wire drawing almost impossible, thus limiting the effective length of the welding wire. This fails to meet the requirements of adaptive welding processes for long, continuous welding wires and also makes it difficult to guarantee high dimensional accuracy.

[0004] Therefore, there is an urgent need to develop a new method for preparing alloy welding wire to solve the problems caused by existing processes, such as poor uniformity of welding wire structure, limited welding processability, short finished product length, and low dimensional accuracy. Summary of the Invention

[0005] In view of the above analysis, the present invention aims to provide a Co-Cr-W high-temperature alloy welding wire and its preparation method, at least to solve one of the following problems existing in the Co-Cr-W high-temperature alloy welding wire prepared by the existing Co-Cr-W high-temperature alloy welding wire preparation method: 1. Poor uniformity of welding wire structure; 2. Limited welding processability; 3. Short finished product length and low dimensional accuracy; 4. Low wear resistance.

[0006] The objective of this invention is mainly achieved through the following technical solutions: This invention provides a method for preparing Co-Cr-W high-temperature alloy welding wire, comprising the following steps: S1: According to the composition of the Co-Cr-W high-temperature alloy welding wire to be prepared, the high-temperature alloy raw materials that meet the composition requirements are melted and cast into electrodes by vacuum induction melting. S2: The electrode is remelted and atomized into powder in a vacuum melting gas atomization device; S3: The atomized powder is sieved to remove particles with a particle size of less than 30 μm and greater than 100 μm, so as to obtain powder with a predetermined particle size of 30-100 μm. S4: After sieving, the powder is placed into a sleeve for degassing, vacuumed, and sealed. S5: The encapsulated casing is subjected to hot isostatic pressing to obtain a dense ingot. S6: Remove the cladding from the surface of the billet after hot isostatic pressing, then heat and pre-roll the billet to obtain a bar. S7: The bar is heated in a tubular resistance heating furnace and then finished rolled on a Y-type wire rod mill to obtain the first wire rod; S8: After annealing the first wire, air-cool it, then straighten and polish it to obtain the second wire; S9: The second wire is lubricated with graphite emulsion, then heated and drawn to obtain the third wire; S10: Grind the third wire to the preset finished diameter to obtain the Co-Cr-W high-temperature alloy welding wire finished product.

[0007] Furthermore, in step S1, the refining temperature of the vacuum induction melting is 1350-1450℃.

[0008] Furthermore, in step S2, the melt superheat is 150-300℃, and the melting time is 25-40 minutes.

[0009] Furthermore, in step S2, the atomization pressure difference is 5000-15000 Pa, the melt diameter at the outlet of the guide tube is 4-5 mm, and the atomizing gas pressure is 5-8 MPa.

[0010] Furthermore, in step S4, the degassing temperature is 300-600℃, and the degassing holding time is 12-48h.

[0011] Furthermore, in step S5, the hot isostatic pressing temperature is 1100-1200℃, the hot isostatic pressing pressure is 140-160MPa, and the hot isostatic pressing time is 4-8h.

[0012] Further, in step S6, the heating temperature is 1130-1180℃, the initial rolling passes are 6-10 passes, the deformation per pass does not exceed 40%, and the final rolling temperature is not lower than 1000℃.

[0013] Furthermore, in step S8, the annealing temperature is 1120~1200℃, and the annealing holding time is 20~50min.

[0014] Further, in step S9, the heating temperature is 900~1200℃, the drawing speed is 0.05-0.3m / s, and the diameter reduction is 0.1-0.3mm per pass.

[0015] The present invention also provides a Co-Cr-W high-temperature alloy welding wire, which is prepared by the above preparation method. The chemical composition by weight percentage is: Cr: 26.0-30.0%, W: 18.0-21.0%, C: 0.7-1.0%, Ni: 4.0-6.0%, V: 0.75-1.00%, B: 0.005-0.1%, with the balance being Co and unavoidable impurities.

[0016] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: 1. This invention effectively avoids the problems of dendrite segregation and coarse reinforcing phases caused by casting processes through atomization powder preparation and hot isostatic pressing, resulting in alloy billets with uniform microstructure and small reinforcing phase size (1-2μm), thus balancing the wear resistance and toughness of the alloy. By controlling the superheat and time of the atomization process and through strict powder sieving and degassing processes, the oxygen content of the powder and the final welding wire is reduced, effectively reducing the porosity sensitivity during welding. Through hot rolling and controllable hot drawing processes, the problem of poor plasticity and difficulty in drawing wires from cast materials is overcome, enabling the production of long, continuous (coil weight over 1kg) welding wire products with high dimensional accuracy (diameter tolerance ±0.02mm), meeting the requirements of modern automated and adaptive welding processes.

[0017] 2. The preparation method provided by this invention has clear steps and well-defined range of key process parameters, which is conducive to achieving stable control of product quality and large-scale production.

[0018] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0019] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. Figure 1 This is a scanning electron microscope backscattered electron image of Embodiment 1 of the present invention; Figure 2 This is a scanning electron microscope backscattered electron image of Comparative Example 1 of the present invention. Detailed Implementation

[0020] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0021] This invention provides a method for preparing Co-Cr-W high-temperature alloy welding wire, comprising the following steps: S1: According to the composition of the Co-Cr-W high-temperature alloy welding wire to be prepared, the high-temperature alloy raw materials that meet the composition requirements are melted and cast into electrodes by vacuum induction melting. The refining temperature is 1350-1450℃. Below 1350℃, the melt temperature is insufficient to completely melt or fully diffuse high-melting-point components (especially W-rich phases), easily leading to uneven melt composition. This can cause compositional segregation during subsequent solidification, creating a potential for the precipitation of coarse, hard phases (such as W-rich TCP phases) and damaging the uniformity of the electrode structure. Excessively high refining temperatures exacerbate the volatilization and burn-off of certain active alloying elements (such as chromium, Cr), causing the final composition to deviate from the design target, affecting the alloy's oxidation resistance and wear resistance. Simultaneously, it intensifies the chemical reaction between the melt and the refractory crucible, increasing the risk of introducing non-metallic inclusions and reducing alloy purity. Limiting the refining temperature to 1350-1450℃ ensures sufficient melting of high-melting-point components, promotes the removal of harmful impurities, and yields a uniform and pure melt. It also effectively avoids problems such as element burn-off, increased inclusions, or poor melt fluidity caused by excessively high or low temperatures.

[0022] S2: The electrode is remelted and atomized into powder in a vacuum melting gas atomization device; Specifically, the melt superheat is controlled within the range of 150-300℃, the melting time is 25-40min, the atomizing gas is high-purity argon, the atomization pressure difference is 5000-15000Pa, the melt diameter at the outlet of the guide tube is 4-5mm, and the atomizing gas pressure is 5-8MPa.

[0023] Melt superheat is a key physical parameter for controlling the morphology and particle size of atomized powder. If the temperature is too low (<150℃), the melt viscosity increases sharply, resulting in poor flowability and easy solidification and blockage in the guide tube, leading to atomization interruption or the production of excessively large particles. If the temperature is too high (>300℃), the reduced surface tension of the melt, while beneficial for atomization, exacerbates the oxidation of droplets during flight and the adhesion of powder after cooling and solidification, increasing the oxygen content of the powder and worsening flowability, leading to powder particle oxidation. A superheat of 150-300℃ ensures good melt flowability, achieves stable atomization, and yields powders with high sphericity and low oxygen content. If the melting time is too short (<25min), the refining is insufficient, and the removal of gases (such as H2, O2) and low-melting-point impurities (such as S, P) in the melt is inadequate, affecting the purity of the powder. If the time is too long (>40min), the active elements in the melt will volatilize and burn off due to prolonged exposure to high temperatures under vacuum or protective atmosphere, causing the alloy composition to deviate from the design value and potentially introducing inclusions.

[0024] The atomizing pressure difference is the main driving force for the gas to break up the melt flow. If the pressure difference is too small (<5000Pa), the gas kinetic energy is insufficient, and the melt flow is not broken up sufficiently, which easily produces a large number of coarse particles (>150μm) and trailing filaments, reducing the yield of qualified powder. If the pressure difference is too large (>15000Pa), the gas flow rate is too high, which will cause excessive cooling and disturbance to the melt flow, resulting in an excessively wide powder particle size distribution and a surge in the proportion of fine powder (<20μm). Fine powder has a higher specific surface area, which will significantly adsorb oxygen and increase the difficulty of subsequent degassing. An atomizing pressure difference of 5000-15000Pa is the key to achieving efficient and controllable crushing and obtaining the target particle size distribution. Gas pressure and atomization pressure difference work together to determine the flow rate and velocity of the atomizing gas. If the pressure is too low (<5MPa), the gas flow rate is insufficient, making it impossible to form a stable, high-kinetic-energy atomizing cone. The cooling rate is low, and the powder is prone to sticking together and has poor sphericity. If the pressure is too high (>8MPa), the gas velocity is extremely fast, and the cooling rate of the droplets is too high, which may cause the droplets to solidify before complete atomization, forming irregular shapes. At the same time, the high-speed airflow can easily re-entrain the solidified fine powder into the high-temperature zone, increasing equipment energy consumption and wear.

[0025] The diameter of the melt at the outlet of the guide tube determines the melt flow rate per unit time and the stability of the initial flow column. If the diameter is too small (<4mm), the melt flow rate is low, the crushing efficiency is poor, and the small flow column is extremely sensitive to airflow disturbances, making it easy to break and form irregular large particles. If the diameter is too large (>5mm), the melt flow column is thick, the surface area of ​​the melt per unit mass is small, and extremely high gas kinetic energy is required for complete crushing. Under a given gas pressure, it is easy to cause incomplete atomization, forming coarse powder or gas trapped inside the particles.

[0026] S3: The atomized powder obtained in step S2 is sieved to remove particles with a particle size of less than 30 μm and greater than 100 μm, so as to obtain powder with a predetermined particle size of 30-100 μm. It should be noted that fine powders with a particle size of less than 30μm have an extremely large specific surface area. During the cooling, collection, and storage processes after atomization, these fine powders will significantly adsorb oxygen and moisture from the environment, forming a thick oxide film. In subsequent steps, it is difficult to completely remove the chemically adsorbed oxygen. High oxygen content entering the final product will seriously impair the toughness, welding processability (increasing spatter and porosity), and high-temperature performance of the welding wire. By actively removing fine powder, the overall oxygen content and surface activity of the powder can be significantly reduced from the source. During atomization, a small amount of irregular powder, such as flakes, trailing filaments, or agglomerated particles, will inevitably be generated. These particles usually have poor flowability and may become stress concentration points or sources of contamination in subsequent processing. Mechanical sieving can effectively filter out irregularly shaped powders and inclusions, improving the purity of the powder. Powders with a particle size of 30-100μm have a moderate particle size and a narrow distribution, which can achieve a high initial filling density and a uniform filling structure during subsequent processes. This is beneficial for obtaining ingots with high density and low porosity, while reducing local shrinkage and deformation caused by excessive differences in powder size.

[0027] S4: The sieved powder obtained in step S3 is loaded into a sleeve for degassing, vacuumed and sealed. Specifically, the inner diameter of the sleeve is 40-50 mm, and the length is 300-400 mm. The degassing temperature is 300-600℃, and the degassing and heat preservation time is 12-48 hours.

[0028] It should be noted that the core purpose of degassing is to remove as much water vapor, gas, and some weakly chemically adsorbed oxygen as possible from the powder surface before densification. If the temperature is too low, it will not provide enough energy to overcome the binding energy between gas molecules (especially chemically adsorbed oxygen) and the powder surface, resulting in low degassing efficiency and high residual gas content. If the temperature is too high, although it can accelerate desorption, it will cause a significant thickening of the oxide layer on the powder surface. The oxide layer is difficult to completely dissolve or reduce through solid-state diffusion during subsequent hot isostatic pressing and will remain in the material as inclusions, damaging toughness and purity. A degassing temperature of 300-600℃ can effectively drive gas desorption and inhibit secondary oxidation of the powder surface. If the degassing time is too short, the gas diffusion will be insufficient, especially the trace amounts of gas trapped inside the powder and particles in the central area of ​​the coating cannot be effectively discharged; if the degassing time is too long, the surface of certain elements may agglomerate on the powder surface due to prolonged heating, and the improvement in degassing effect will not be significant; a degassing holding time of 12-48 hours and a degassing temperature of 300-600℃ can effectively remove most of the removable gases and stably control the oxygen, nitrogen and other gas contents of the powder at a low level, thereby improving the purity of the alloy.

[0029] S5: The encapsulated package from step S4 is subjected to hot isostatic pressing to obtain a dense ingot. Specifically, the hot isostatic pressing temperature is 1100-1200℃, the hot isostatic pressing pressure is 140-160MPa, and the hot isostatic pressing time is 4-8h.

[0030] It should be noted that densification in hot isostatic pressing (HIP) mainly relies on the yielding, creep, and mass diffusion of powder particles at high temperatures. For Co-Cr-W superalloys, the matrix has high high-temperature strength and recrystallization temperature. Below 1100℃, the powder particles lack plasticity, and the atomic diffusion rate is slow, making it difficult to completely eliminate interparticle porosity through sufficient plastic deformation and diffusion. This easily leads to residual closed pores in the billet or insufficient interfacial bonding strength, affecting the mechanical properties and fatigue life of the final product. If the HIP temperature is too high, the strengthening phases (W-rich TCP phase and carbides) in the Co-Cr-W alloy will undergo small-particle re-dissolution and large-particle coarsening. The coarse hard phases will damage the continuity of the matrix, easily becoming crack initiation points during subsequent hot working, and may also lead to a decrease in welding wire toughness. Pressure is the main driving force for plastic deformation of powder particles and closure of pores. For Co-Cr-W alloy powder, higher pressure is required to overcome its deformation resistance at high temperature. Pressure below 140MPa may not be enough to completely close all pores, especially irregular pores or pores located at particle overlap, resulting in insufficient product density. Within the selected temperature range, a pressure of 140-160 MPa works synergistically with temperature, efficiently achieving densification by promoting dislocation slip and creep mechanisms, thus allowing full densification to be achieved within a relatively reasonable holding time. Excessive pressure, while beneficial for densification, places higher demands on hot isostatic pressing equipment, increasing costs, and excessive plastic deformation may introduce unfavorable textures or internal stresses. Insufficient holding time leads to inadequate diffusion, resulting in residual particle interfaces and potentially incompletely healed micropores or weak particle interfaces within the alloy, leading to weak performance in those areas. Excessive holding time, in the later stages of holding, results in very limited density improvement, instead providing more time for the coarsening of the strengthening phase, potentially causing its average size to exceed the ideal range, while also increasing energy consumption and production cycle. The synergistic effect of temperature, pressure, and time in this hot isostatic pressing step ensures complete densification of the alloy powder while effectively suppressing the coarsening of the strengthening phase and unfavorable phase transformations, resulting in a high-quality ingot with uniform composition, fine microstructure, and no internal defects.

[0031] S6: Remove the cladding from the surface of the billet after hot isostatic pressing, then heat and pre-roll the billet to obtain a bar. Specifically, after removing the cladding on the surface of the billet after hot isostatic pressing, the billet is heated to 1130-1180℃ and rolled into bars with a diameter of 8-12mm in 6-10 passes. The deformation in each pass does not exceed 40%, and the final rolling temperature is not lower than 1000℃.

[0032] It should be noted that below 1130℃, the deformation resistance of Co-Cr-W superalloys increases sharply, while plasticity decreases, making them highly susceptible to surface cracks and even internal cracking during rolling, resulting in significant processing risks. Excessively high temperatures can lead to abnormal grain growth, impairing the material's mechanical properties, and causing excessive dissolution or coarsening of hard reinforcing phases (such as TCP phase) in the alloy. Setting the heating temperature between 1130-1180℃ ensures that the billet can be rolled within this temperature range, fully utilizing the material's high-temperature plasticity for smooth deformation. Simultaneously, it ensures that dynamic and static recrystallization processes are effectively triggered during rolling deformation and inter-pass heat treatment, effectively eliminating any remaining original powder particle boundaries after hot isostatic pressing and resulting in a uniform grain structure. In the multi-pass rolling process of Co-Cr-W superalloys, the temperature continuously decreases during each heat. Furthermore, the high strain rate deformation process prevents complete dynamic recrystallization to adequately soften the alloy. If the deformation amount per heat is too large (e.g., exceeding 40%), severe work hardening occurs, making cracking highly likely. Limiting the deformation amount per heat to within 40% ensures a gentle and controllable deformation process. A final rolling temperature of no less than 1000℃ ensures the material remains within a temperature range with good plasticity until the end of deformation. If the final rolling temperature is too low, the material may have entered a low-plasticity region in the final stage, making it highly susceptible to cracking during the final deformation. This step, through multi-pass, controllable deformation, transforms large-sized ingots into small-sized bars.

[0033] S7: The bar is heated in a tubular resistance heating furnace and then finished rolled on a Y-type wire rod mill to obtain the first wire rod; Specifically, the bar with a diameter of 8-12mm obtained in step S6 is heated to 1130-1180℃ in a tubular resistance heating furnace, and then precision rolled on a Y-type wire rod mill. The deformation per heat is no more than 30%, and the final rolling temperature is greater than 1000℃, until the first wire rod with a diameter of Φ4.0±0.1mm is obtained.

[0034] This step, the finish rolling of the bar stock, serves a similar purpose to step S6. The heating temperature is limited to 1130-1180℃ to reduce deformation resistance, prevent cracking, and promote dynamic recrystallization for continuous grain refinement. When finishing rolling to near the target size (Φ4.0mm), to ensure dimensional accuracy and surface quality, the deformation per pass may be small; the deformation per pass is set to no more than 30%, ensuring a gentle and controllable deformation process. The final rolling temperature in this step is exactly the same as the initial rolling requirement (≥1000℃) to ensure the material retains sufficient plasticity in the final forming stage, preventing surface cracks or internal damage caused by excessively low temperatures.

[0035] S8: After annealing the first wire, air-cool it, then straighten and polish it to obtain the second wire; Specifically, the annealing temperature is 1120~1200℃, the annealing holding time is 20~50min, followed by air cooling; then straightening is performed, and the wire is ground to Φ3.6±0.1mm on a centerless grinder to remove surface oxide scale and defects, thus obtaining the second wire.

[0036] It should be noted that after multiple hot rolling passes (S6 and S7), significant dislocation density and work hardening accumulate within the wire rod. Although dynamic recrystallization occurs, the microstructure remains in a non-equilibrium state, with high internal stress and reduced plasticity reserves. Setting the annealing temperature at 1120~1200℃ aims to ensure a sufficiently high temperature to fully trigger the static recrystallization process. Holding at this temperature for 20-50 minutes provides ample time for recrystallization nucleation and growth, as well as dislocation annihilation, thereby completely eliminating the work hardening caused by the preceding hot rolling, significantly reducing deformation resistance, restoring and optimizing the wire rod's plasticity, and providing easily deformable and uniform billets for subsequent high-precision hot drawing processes. Simultaneously, it can improve any local microstructure inhomogeneities that may exist during hot rolling through recrystallization and grain growth, resulting in a more uniform, equiaxed fine-grained microstructure. It also contributes to a more stable size and distribution of strengthening phases (such as carbides and TCP phases) in the alloy. After annealing, air cooling is performed at a relatively slow rate to prevent the generation of new excessive thermal stress or quenching cracks during the cooling process; it also facilitates the precipitation of fine, stable reinforcing phases. Subsequent straightening and polishing (to Φ3.6±0.1mm) aim to remove oxide scale, improve the geometric quality and surface integrity of the wire, and provide dimensionally accurate and clean blanks for subsequent processes by eliminating shape deviations and surface defects.

[0037] S9: The second wire is lubricated with graphite emulsion, then heated and drawn to obtain the third wire; Specifically, the second wire is lubricated with graphite emulsion and heated online to 900~1200℃ for drawing. The drawing speed is 0.05-0.3m / s, and the diameter is reduced by 0.1-0.3mm per pass until the wire is drawn to the finished diameter + (0.1~0.2)mm, thus obtaining the third wire.

[0038] It should be noted that using graphite emulsion lubrication for the second wire effectively isolates the alloy from direct contact with the die, significantly reducing the coefficient of friction and drawing force, minimizing die wear and adhesion. The uniform graphite coating, to a certain extent, isolates air during heating and drawing, slowing down high-temperature oxidation of the wire surface, ensuring uniform metal flow, and preventing surface scratches, roughening, or "vibration marks" caused by uneven friction. This contributes to obtaining dimensionally stable and smooth-surfaced drawn wires. A heating temperature of 900~1200℃ ensures that the alloy remains within a well-ductile and controllable thermal processing window throughout the drawing process. Excessively high temperatures can easily lead to overheating, grain coarsening, or accelerated surface oxidation. Drawing speeds that are too low (<0.05m / s) severely reduce the alloy's drawing deformation temperature and affect production efficiency, while potentially causing excessive heating time leading to excessive surface oxidation or grain growth. Speeds that are too high (>0.3m / s) can cause lubrication failure, deformation instability leading to breakage, or surface quality deterioration. Too small a reduction (<0.1mm) will lead to a surge in the number of passes, reduced efficiency, and may result in insufficient deformation, failing to effectively drive dynamic recrystallization. Too large a reduction (>0.3mm) will result in excessive work done per pass, causing severe work hardening, significantly increasing drawing force and die wear, and greatly increasing the risk of wire breakage. A reduction of 0.1-0.3mm can balance processing efficiency, work hardening, and yield while ensuring a certain level of processing efficiency.

[0039] S10: Grind the third wire to the preset finished diameter to obtain the Co-Cr-W high-temperature alloy welding wire finished product.

[0040] Specifically, the third wire is ground down to a diameter of 0.1-0.2 mm using a belt sander to obtain the final welding wire with a diameter tolerance of ±0.02 mm.

[0041] This invention also provides a Co-Cr-W high-temperature alloy welding wire, prepared using the above-described method, with the following chemical composition by weight percentage: Cr: 26.0-30.0%, W: 18.0-21.0%. C: 0.7-1.0%, Ni: 4.0-6.0%, V: 0.75-1.00%, B 0.005-0.1%, balance Co and unavoidable impurities.

[0042] The microstructure of the Co-Cr-W high-temperature alloy welding wire prepared by this invention includes: a γ-Co solid solution matrix, a W-rich TCP strengthening phase, and a Cr-rich carbide strengthening phase. The volume fraction of the TCP phase is about 5-13%, and the volume fraction of the carbide phase is about 15-20%. Both are nearly equiaxed fine particles dispersed in the matrix with an average size of 1.0-3.0 μm.

[0043] The Co-Cr-W high-temperature alloy welding wire prepared by this invention has a diameter tolerance of ≤0.02mm (e.g., 0.015-0.018mm), exhibiting high dimensional accuracy; the single-coil length can reach 30-100m, making it suitable for automated welding processes; the 950℃ high-temperature wear rate of the weld overlay prepared by the Co-Cr-W high-temperature alloy welding wire is [not specified]. (like ).

[0044] Example 1 The chemical composition of the Co-Cr-W high-temperature alloy welding wire to be prepared in this embodiment, by weight percentage, is: Cr: 28.5%, W: 19.5%, C: 0.85%, Ni: 5.0%, V: 0.85%, B: 0.01%, with the balance being Co and unavoidable impurities.

[0045] Prepared by the following method: S1: According to the composition of the Co-Cr-W high-temperature alloy welding wire to be prepared, the high-temperature alloy raw materials that meet the composition requirements are melted and cast into electrodes by vacuum induction melting, and the refining temperature is 1400℃. S2: The electrode is remelted and atomized into powder in a vacuum melting gas atomization device; The melt superheat is controlled at 200℃, the melting time is 30min, the atomizing gas is high-purity argon, the atomization pressure difference is 10000Pa, the melt diameter at the outlet of the guide tube is 4.5mm, and the atomizing gas pressure is 6.5MPa.

[0046] S3: The atomized powder obtained in step S2 is sieved to remove particles with a particle size of less than 30 μm and greater than 100 μm, so as to obtain powder with a predetermined particle size of 30-100 μm. S4: The sieved powder obtained in step S3 is loaded into a sleeve for degassing, vacuumed and sealed. The inner diameter of the sleeve is 45mm, and the length is 350mm. The degassing temperature is 450℃, and the degassing holding time is 24h.

[0047] S5: The encapsulated package from step S4 is subjected to hot isostatic pressing to obtain a dense ingot. The hot isostatic pressing temperature was 1150℃, the hot isostatic pressing pressure was 150MPa, and the hot isostatic pressing time was 6h.

[0048] S6: Remove the cladding from the surface of the billet after hot isostatic pressing, then heat and pre-roll the billet to obtain a bar. The process involves removing the cladding from the surface of the billet after hot isostatic pressing, heating the billet to 1150℃, and rolling it into Φ10mm bars in eight passes, with a deformation of 25-35% per pass and a final rolling temperature of 1050℃.

[0049] S7: The bar is heated in a tubular resistance heating furnace and then finished rolled on a Y-type wire rod mill to obtain the first wire rod; In step S6, the Φ10mm bar is heated to 1150℃ in a tubular resistance heating furnace and then finished rolled on a Y-type wire rod mill for a total of 5 heats, with a deformation of 15%-30% per heat, and a final rolling temperature of 1050℃, to obtain the first wire rod with Φ4.0±0.1mm.

[0050] S8: After annealing the first wire, air-cool it, then straighten and polish it to obtain the second wire; The annealing temperature was 1160℃, the annealing holding time was 35 minutes, and then the wire was air-cooled. The wire was then straightened and polished to Φ3.6±0.1mm on a centerless grinder to obtain the second wire.

[0051] S9: The second wire is lubricated with graphite emulsion, then heated and drawn to obtain the third wire; The second wire is lubricated with graphite emulsion and heated online to 1000℃ for drawing at a speed of 0.15m / s. The diameter is reduced by 0.15-0.25mm per pass until the wire is drawn to a size of Φ1.3mm, thus obtaining the third wire.

[0052] S10: The third wire is ground down by 0.1 mm using a belt sander to obtain a finished Co-Cr-W high-temperature alloy welding wire with a diameter of Φ1.2±0.015 mm and a coil weight of 1.5 kg.

[0053] Example 2 The chemical composition of the Co-Cr-W high-temperature alloy welding wire to be prepared in this embodiment, by weight percentage, is: Cr: 29.5%, W: 18.5%, C: 1.0%, Ni: 4.5%, V: 0.95%, B: 0.005%, with the balance being Co and unavoidable impurities.

[0054] Prepared by the following method: S1: According to the composition of the Co-Cr-W high-temperature alloy welding wire to be prepared, the high-temperature alloy raw materials that meet the composition requirements are melted and cast into electrodes by vacuum induction melting, and the refining temperature is 1370℃. S2: The electrode is remelted and atomized into powder in a vacuum melting gas atomization device; The melt superheat is controlled at 180℃, the melting time is 35min, the atomizing gas is high-purity argon, the atomization pressure difference is 8000Pa, the melt diameter at the outlet of the guide tube is 4.5mm, and the atomizing gas pressure is 6.0MPa.

[0055] S3: The atomized powder obtained in step S2 is sieved to remove particles with a particle size of less than 30 μm and greater than 100 μm, so as to obtain powder with a predetermined particle size of 30-100 μm. S4: The sieved powder obtained in step S3 is loaded into a sleeve for degassing, vacuumed and sealed. The inner diameter of the sleeve is 45mm, and the length is 350mm. The degassing temperature is 450℃, and the degassing holding time is 24h.

[0056] S5: The encapsulated package from step S4 is subjected to hot isostatic pressing to obtain a dense ingot. The hot isostatic pressing temperature was 1120℃, the hot isostatic pressing pressure was 155MPa, and the hot isostatic pressing time was 7h.

[0057] S6: Remove the cladding from the surface of the billet after hot isostatic pressing, then heat and pre-roll the billet to obtain a bar. The process involves removing the cladding from the surface of the billet after hot isostatic pressing, heating the billet to 1170℃, and rolling it into Φ11mm bars in seven passes, with a deformation of 20-38% per pass and a final rolling temperature of 1030℃.

[0058] S7: The bar is heated in a tubular resistance heating furnace and then finished rolled on a Y-type wire rod mill to obtain the first wire rod; In step S6, the Φ11mm bar is heated to 1175℃ in a tubular resistance heating furnace and then finished rolled on a Y-type wire rod mill for a total of 6 heats, with a deformation of 10%-28% per heat and a final rolling temperature of 1010℃, to obtain the first wire rod with Φ4.0±0.1mm.

[0059] S8: After annealing the first wire, air-cool it, then straighten and polish it to obtain the second wire; The annealing temperature was 1180℃, the annealing holding time was 25 minutes, and then the wire was air-cooled. The wire was then straightened and polished to Φ3.6±0.1mm on a centerless grinder to obtain the second wire.

[0060] S9: The second wire is lubricated with graphite emulsion, then heated and drawn to obtain the third wire; The second wire is lubricated with graphite emulsion and heated online to 1050℃ for drawing. The drawing speed is 0.1m / s, and the diameter is reduced by 0.12-0.18mm per pass until the wire is drawn to a size of Φ1.7mm, thus obtaining the third wire.

[0061] S10: The third wire is ground down by 0.1 mm using a belt sander to obtain a finished Co-Cr-W high-temperature alloy welding wire with a diameter of Φ1.6±0.018 mm and a coil weight of 1.8 kg.

[0062] Example 3 The chemical composition of the Co-Cr-W high-temperature alloy welding wire to be prepared in this embodiment, by weight percentage, is: Cr: 27.0%, W: 20.5%, C: 0.75%, Ni: 5.5%, V: 0.78%, B: 0.008%, with the balance being Co and unavoidable impurities.

[0063] Prepared by the following method: S1: According to the composition of the Co-Cr-W high-temperature alloy welding wire to be prepared, the high-temperature alloy raw materials that meet the composition requirements are melted and cast into electrodes by vacuum induction melting, and the refining temperature is 1420℃. S2: The electrode is remelted and atomized into powder in a vacuum melting gas atomization device; The melt superheat was controlled at 250℃, the melting time was 28min, the atomizing gas was high-purity argon, the atomization pressure difference was 13000Pa, the melt diameter at the outlet of the guide tube was 4.5mm, and the atomizing gas pressure was 7.5MPa.

[0064] S3: The atomized powder obtained in step S2 is sieved to remove particles with a particle size of less than 30 μm and greater than 100 μm, so as to obtain powder with a predetermined particle size of 30-100 μm. S4: The sieved powder obtained in step S3 is loaded into a sleeve for degassing, vacuumed and sealed. The inner diameter of the sleeve is 45mm, and the length is 350mm. The degassing temperature is 450℃, and the degassing holding time is 24h.

[0065] S5: The encapsulated package from step S4 is subjected to hot isostatic pressing to obtain a dense ingot. The hot isostatic pressing temperature was 1180℃, the hot isostatic pressing pressure was 145MPa, and the hot isostatic pressing time was 5h.

[0066] S6: Remove the cladding from the surface of the billet after hot isostatic pressing, then heat and pre-roll the billet to obtain a bar. The process involves removing the cladding from the surface of the billet after hot isostatic pressing, heating the billet to 1140℃, and rolling it into Φ9mm bars in 9 passes, with a deformation of 28-40% per pass and a final rolling temperature of 1060℃.

[0067] S7: The bar is heated in a tubular resistance heating furnace and then finished rolled on a Y-type wire rod mill to obtain the first wire rod; In step S6, the Φ9mm bar is heated to 1145℃ in a tubular resistance heating furnace and then finished rolled on a Y-type wire rod mill for a total of 7 heats, with a deformation of 8%-25% per heat, and a final rolling temperature of 1040℃, to obtain the first wire rod with Φ4.0±0.1mm.

[0068] S8: After annealing the first wire, air-cool it, then straighten and polish it to obtain the second wire; The annealing temperature was 1130℃, the annealing holding time was 45 minutes, and then the wire was air-cooled. The wire was then straightened and polished to Φ3.6±0.1mm on a centerless grinder to obtain the second wire.

[0069] S9: The second wire is lubricated with graphite emulsion, then heated and drawn to obtain the third wire; The second wire is lubricated with graphite emulsion, heated online to 950℃ and drawn at a speed of 0.25m / s, with a diameter reduction of 0.20-0.30mm per pass, until the wire is drawn to a size of Φ0.9mm, thus obtaining the third wire.

[0070] S10: The third wire is ground down by 0.1 mm using a belt sander to obtain a finished Co-Cr-W high-temperature alloy welding wire with a diameter of Φ0.8±0.015 mm and a coil weight of 1.2 kg.

[0071] Comparative Example 1 The Co-Cr-W alloy welding wire, prepared using the same alloy composition as in Example 1 and through a conventional casting and wire cutting process, includes the following steps: S1: Vacuum induction melting and casting: Raw materials that meet the composition requirements are loaded into a vacuum induction melting furnace and melted under a vacuum degree ≤10Pa. The refining temperature is 1400℃ and the refining time is 30 minutes. The molten alloy is then poured into a cast iron mold preheated to 300-400℃ to form a cylindrical ingot with a diameter of 80 mm × 300 mm. S2: Homogenization heat treatment: The ingot is placed in a box-type resistance furnace for homogenization annealing, heated to 1200℃, held for 8 hours, and then cooled to 600℃ in the furnace before being removed from the furnace and air-cooled. S3: Reheat the homogenized ingot to 1180℃, hold for 2 hours, and perform multi-fire forging, a total of 5-7 fires, to forge the Φ80 mm ingot into a Φ20 mm round bar. The deformation amount per fire is about 30-50%, the final forging temperature is 1000℃, and the forging is air-cooled. S4: The forged bar is solution treated at 1150℃ for 2 hours (air cooling) to optimize its processing performance and straighten it; S5: Grind the Φ20 mm bar on a precision centerless grinder to gradually reduce the diameter, grinding it to Φ15 mm, Φ10 mm, Φ6 mm, and Φ3 mm in sequence. Then, further process the Φ3 mm bar to the target size Φ1.2±0.05 mm on a special multi-axis CNC lathe or rotary forging machine by precision turning or rotary forging. S6: Cut it into fixed lengths of 500 mm, polish the surface of the cut short straight strips and sharpen the ends to obtain the final welding wire product. The product is in the form of straight strips and cannot be coiled.

[0072] Comparative Example 2 The Co-Cr-W high-temperature alloy welding wire of the comparative example preparation Example 1 was prepared in a similar process to that of Example 1, except that conventional hot pressing (1100℃, 100MPa, 2h) was used instead of hot isostatic pressing.

[0073] Comparative Example 3 The Co-Cr-W high-temperature alloy welding wire prepared in this comparative example has a similar preparation process to that of Example 1, except that: In step S5, the hot isostatic pressing temperature is 1250℃; In step S6, the initial rolling process is completed in only 4 passes, with a deformation of 55% per pass and a final rolling temperature of 950℃. In step S9, the hot drawing speed is 0.45 m / s; The remaining steps are the same as in Example 1.

[0074] Table 1 shows a comparison of the wear resistance of the examples and comparative examples; Table 3 shows the microstructure and product geometry of the examples and comparative examples.

[0075] Table 1. Abrasion resistance of the examples and comparative examples

[0076] Table 2 shows the microstructure and product geometry of the examples and comparative examples.

[0077] The preparation method of the embodiments of the present invention meets the requirements of the present invention, with uniform structure, good wear resistance and weldability. Comparative Example 1 uses traditional casting and machining processes to prepare welding wire, and its product shape (short straight bar) can no longer meet the basic requirements of modern automated welding, resulting in poor performance. The comparative example uses atomized powder starting point, which is better than traditional casting in terms of structural uniformity, but due to insufficient density (hot pressing), the product has closed pores, high wire breakage rate, and lower performance than the present invention. The hot isostatic pressing temperature, hot rolling process, and hot drawing speed of Comparative Example 3 do not meet the requirements of the present invention, resulting in deteriorated structure, unstable processing, and overall decline and large fluctuation in final performance.

[0078] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a Co-Cr-W high-temperature alloy welding wire, characterized in that, Includes the following steps: S1: According to the composition of the Co-Cr-W high-temperature alloy welding wire to be prepared, the high-temperature alloy raw materials that meet the composition requirements are melted and cast into electrodes by vacuum induction melting. S2: The electrode is remelted and atomized into powder in a vacuum melting gas atomization device; S3: The atomized powder is sieved to remove particles with a particle size of less than 30 μm and greater than 100 μm, so as to obtain powder with a predetermined particle size of 30-100 μm. S4: After sieving, the powder is placed into a sleeve for degassing, vacuumed, and sealed. S5: The encapsulated casing is subjected to hot isostatic pressing to obtain a dense ingot. S6: Remove the cladding from the surface of the billet after hot isostatic pressing, then heat and pre-roll the billet to obtain a bar. S7: The bar is heated in a tubular resistance heating furnace and then finished rolled on a Y-type wire rod mill to obtain the first wire rod; S8: After annealing the first wire, air-cool it, then straighten and polish it to obtain the second wire; S9: The second wire is lubricated with graphite emulsion, then heated and drawn to obtain the third wire; S10: Grind the third wire to the preset finished diameter to obtain the Co-Cr-W high-temperature alloy welding wire finished product.

2. The preparation method according to claim 1, characterized in that, In step S1, the refining temperature of the vacuum induction melting is 1350-1450℃.

3. The preparation method according to claim 1, characterized in that, In step S2, the melt superheat is 150-300℃ and the melting time is 25-40 minutes.

4. The preparation method according to claim 3, characterized in that, In step S2, the atomization pressure difference is 5000-15000 Pa, the melt diameter at the outlet of the guide tube is 4-5 mm, and the atomizing gas pressure is 5-8 MPa.

5. The preparation method according to claim 1, characterized in that, In step S4, the degassing temperature is 300-600℃, and the degassing holding time is 12-48h.

6. The preparation method according to claim 1, characterized in that, In step S5, the hot isostatic pressing temperature is 1100-1200℃, the hot isostatic pressing pressure is 140-160MPa, and the hot isostatic pressing time is 4-8h.

7. The preparation method according to claim 1, characterized in that, In step S6, the heating temperature is 1130-1180℃, the initial rolling passes are 6-10 passes, the deformation per pass does not exceed 40%, and the final rolling temperature is not lower than 1000℃.

8. The preparation method according to claim 1, characterized in that, In step S8, the annealing temperature is 1120~1200℃, and the annealing holding time is 20~50min.

9. The preparation method according to claim 1, characterized in that, In step S9, the heating temperature is 900~1200℃, the drawing speed is 0.05-0.3m / s, and the diameter reduction is 0.1-0.3mm per pass.

10. A Co-Cr-W high-temperature alloy welding wire, prepared by the preparation method according to any one of claims 1-9, characterized in that, The chemical composition by weight percentage is as follows: Cr: 26.0-30.0%, W: 18.0-21.0%, C: 0.7-1.0%, Ni: 4.0-6.0%, V: 0.75-1.00%, B: 0.005-0.1%, with the balance being Co and unavoidable impurities.

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