A preparation method for improving performance uniformity of electric heating alloy Fe-Cr-Al wire

Abstract

The application discloses a preparation method for improving performance uniformity of an electrothermal alloy Fe-Cr-Al wire and relates to the technical field of metal material processing. The preparation method for improving performance uniformity of the electrothermal alloy Fe-Cr-Al wire solves the brittle fracture problem in the drawing process of the Fe-Cr-Al wire through the synergistic effect of temperature control, segmented deformation and precise annealing, cracks and other defects do not exist on the surface of the product, and the production qualified rate can be significantly improved. The three-stage drawing and the stage annealing are matched with each other, the wire material organization becomes small and uniform, coarse grains do not exist in the center part, and the organization difference between the edge part and the center part is greatly reduced, laying a solid foundation for the uniformity of the performance. The resistance of the product is uniformly distributed, the pitch is consistent after the product is wound into a resistance wire, heating efficiency fluctuation caused by uneven performance is avoided, and the reliability of terminal equipment use is improved.

Description

Technical Field

[0001] This application belongs to the field of metal material processing technology, and in particular relates to a preparation method for improving the uniformity of the properties of electrothermal alloy iron-chromium-aluminum wire. Background Technology

[0002] Electrothermal alloys, as key functional materials for converting electrical energy into heat energy, are widely used in many fields such as industry, energy, military, and people's livelihood. Among them, iron-chromium-aluminum materials have become the most widely used and applied category of electrothermal materials due to their advantages such as high resistivity, good thermal stability, long service life, high energy conversion efficiency, and low cost. Wire products alone account for more than 80% of the market share.

[0003] However, the matrix of iron-chromium-aluminum materials is ferrite, and the high content of chromium and aluminum makes them inherently brittle. Under conventional processing techniques, they exhibit poor plasticity and toughness, making them highly susceptible to cracking and even fracture during production. A deeper analysis of the root causes of this brittleness reveals several temperature ranges: At room temperature (below 25℃), brittleness is due to coarse grains in the cast and hot-rolled states, with the ductile-brittle transition temperature close to room temperature, resulting in a very high risk of brittle fracture during room temperature drawing in winter; at a medium temperature of approximately 475℃, a chromium-rich α' phase precipitates, forming a two-phase region and leading to brittleness; in the medium temperature range of 520–800℃, a δ phase and carbides precipitate, increasing the material's strength but decreasing its plasticity; above 1000℃, rapid grain growth further reduces plasticity.

[0004] These brittleness issues directly lead to subsequent defects in use: surface cracks generated during the drawing process reduce the local strength of the iron-chromium-aluminum wire, resulting in uneven winding pitch during the winding of resistance wires due to uneven strength; simultaneously, cracks alter the cross-sectional shape of the wire, causing localized changes in resistance and ultimately leading to uneven resistance. Existing manufacturing processes fail to address these brittleness issues specifically, neither effectively breaking up coarse grains and improving microstructure uniformity, nor avoiding the formation range of brittle precipitates, resulting in significant fluctuations in product performance and making it difficult to meet the requirements of high-end applications for uniform resistance and winding pitch. Summary of the Invention

[0005] To address some or all of the technical problems existing in the prior art, this application provides a preparation method for improving the uniformity of the properties of electrothermal alloy iron-chromium-aluminum wire.

[0006] This application provides a method for preparing electrothermal alloy iron-chromium-aluminum wire with improved performance uniformity, comprising the following steps: Step S1: Drawing temperature control, the drawing temperature of the iron-chromium-aluminum raw material wire rod is always maintained above 20℃; Step S2: First stage drawing and annealing. The first stage drawing is carried out on the raw material wire rod. The drawing reduction rate is 70-90%. After the drawing is completed, annealing is carried out. After annealing, the steel wire is quickly sent to the water cooling section for cooling. Step S3: Second stage drawing and annealing. The steel wire treated in step S2 is drawn in the second stage with a reduction in surface area of ​​45-70%. After drawing, annealing is performed. After annealing, the steel wire is quickly sent to the water cooling section for cooling. Step S4: Third stage drawing and annealing. The steel wire treated in step S3 is drawn in the third stage with a reduction in surface area of ​​40-65%. After drawing to the finished product specifications, it is annealed. After annealing, the steel wire is quickly sent to the water cooling section for cooling, thereby obtaining iron-chromium-aluminum wire with uniform properties.

[0007] Preferably, the annealing processes in steps S2, S3 and S4 are all performed using a continuous bright annealing furnace.

[0008] Preferably, the annealing process parameters in steps S2, S3 and S4 are in the same range, the annealing heating temperature is 820-850℃ and the heating and holding time is 60-120 seconds.

[0009] Preferably, during water cooling in steps S2, S3 and S4, the cooling rate range is 50 to 200°C / second.

[0010] The preparation method for improving the uniformity of properties of electrothermal alloy iron-chromium-aluminum wire in this application has the following advantages and positive effects: By combining temperature control, segmented deformation, and precise annealing, the problem of brittle fracture during the drawing process of iron-chromium-aluminum wire was solved. The product surface is free of cracks and other defects, significantly improving the production qualification rate. The three-stage drawing process combined with staged annealing results in a finer and more uniform wire microstructure, eliminating coarse grains in the center and greatly reducing the microstructure difference between the edges and the center, laying a solid foundation for uniform performance. The product has a uniform resistance distribution, and the pitch remains consistent after winding into resistance wire, avoiding heating efficiency fluctuations caused by uneven performance and improving the reliability of end-use equipment. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for further understanding of the embodiments of this application and constitute a part of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1A schematic diagram of the surface state of iron-chromium-aluminum wire prepared by traditional drawing process clearly shows the surface cracks generated in the iron-chromium-aluminum wire during the drawing process due to its brittleness. Figure 2 This is a schematic diagram of the surface condition of the iron-chromium-aluminum wire drawn using the preparation method of the present invention. It clearly shows that the surface of the wire is smooth and flat, without any cracks or other defects. Figure 3 A schematic diagram of the state of iron-chromium-aluminum wire prepared by traditional process after winding into resistance wire shows the phenomenon of uneven winding pitch caused by uneven wire strength. Figure 4 This is a schematic diagram showing the state of the iron-chromium-aluminum wire obtained by the preparation method of the present invention after it is wound into a resistance wire, which shows that the winding pitch of the resistance wire is uniform. Figure 5 A magnified schematic diagram of a portion of an iron-chromium-aluminum resistance wire prepared by a traditional process, highlighting the crack defects that occur at locations with uneven winding pitch; Figure 6 This is a partially enlarged schematic diagram of the iron-chromium-aluminum resistance wire prepared by the method of the present invention, showing that the winding pitch is uniform and there are no cracks or defects. Figure 7 This is a comparison chart showing the relationship between the resistance uniformity of iron-chromium-aluminum wire and surface defects. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0013] The preparation method for improving the uniformity of the properties of electrothermal alloy iron-chromium-aluminum wire of this application includes the following steps: Step S1: Temperature control during drawing. The drawing temperature of the iron-chromium-aluminum raw material wire rod should always be maintained above 20℃. In winter, the raw material wire rod can be preheated to 20-150℃ in an electric heating furnace to ensure that the drawing process is carried out within the toughness temperature range.

[0014] Step S2: First-stage drawing and annealing. The first-stage drawing is performed on the raw wire rod, with a reduction in surface area of ​​70-90%. This range is the optimal deformation range for the initial drawing stage of the iron-chromium-aluminum wire. Below 70%, the deformation energy is insufficient to effectively break up the coarse grains in the as-cast structure, and it is impossible to completely eliminate defects such as porosity and segregation in the original structure. Subsequent annealing and recrystallization will also struggle to form uniform and fine grains. Above 90%, the wire experiences excessive deformation stress, easily leading to surface scratches, internal cracks, and other damage. Furthermore, the degree of work hardening is too high, increasing the difficulty of stress relief during subsequent annealing. After drawing, annealing is performed to ensure complete elimination of work hardening and promote recrystallization. After annealing, the wire is quickly sent to the water-cooling section for cooling to inhibit abnormal grain growth and brittle phase precipitation, locking in a fine recrystallized structure. Step S3: Second-stage drawing and annealing. The steel wire treated in step S2 undergoes a second-stage drawing process with a reduction in surface area of ​​45-70%, falling within the medium deformation range of 45-70%. This range follows the large deformation process of the first stage and is crucial for microstructure refinement and wire performance control. Below 45%, the deformation is insufficient to further refine the grains after the first-stage annealing and to reduce the grain difference between the edges and center of the wire, resulting in limited improvement in microstructure uniformity. Above 70%, it approaches the large deformation threshold, which can easily lead to a decrease in wire toughness and exacerbate stress concentration at the edges, increasing the risk of brittle fracture. After drawing, annealing is performed, followed by rapid water cooling to further optimize ductility and toughness. Step S4: Third-stage drawing and annealing. The steel wire treated in step S3 undergoes a third-stage drawing process with a reduction in surface area of ​​40-65%. This range represents the optimized deformation amount for the finished product stage. It avoids the problems of insufficient microstructure refinement and residual stress that are difficult to completely eliminate through subsequent annealing when the deformation amount is below 40%, while also avoiding the risks of surface cracking, increased internal stress concentration, and decreased toughness caused by excessive deformation when the deformation amount is above 65%. This deformation amount can moderately regularize the internal grains of the wire while retaining the microstructure refinement results of the first two stages, further reducing the microstructure difference between the edge and the core, making the ferrite grain arrangement more uniform and dense, and providing an ideal microstructure for the subsequent annealing process. After drawing to the finished specifications, annealing is performed. After annealing, the steel wire is quickly sent to the water-cooling section for cooling, thereby obtaining a uniform iron-chromium-aluminum wire, completely eliminating residual internal stress, locking in a uniform and fine ferrite microstructure, and meeting the requirements for uniform resistance and winding pitch.

[0015] The reduction rate gradient distribution follows the "large, small, small" principle. The first stage involves large deformation to break up coarse grains, while the subsequent stages involve small deformation to refine the microstructure and ensure accuracy, balancing microstructure uniformity with processing safety.

[0016] In the annealing process of steps S2, S3 and S4, a continuous bright annealing furnace is used for annealing. The annealing process parameters in steps S2, S3 and S4 are the same, with an annealing heating temperature of 820-850℃ and a heating and holding time of 60-120 seconds. When cooling in the water cooling section in steps S2, S3 and S4, the cooling rate is 50-200℃ / second. Graphite lubricant can be used to reduce processing friction during drawing.

[0017] Annealing temperature (820~850℃) can avoid the precipitation range of brittle phase, holding time (60~120 seconds) can adapt to different stages of microstructure, and rapid water cooling (50~200℃ / second) can inhibit grain growth and brittle phase precipitation. The three work together to ensure the plasticity and toughness of the wire.

[0018] This application addresses the multi-temperature brittleness issue of iron-chromium-aluminum materials through the aforementioned process, ultimately improving the uniformity of the wire's microstructure and properties. The preparation process and its effects are detailed below, using specific product specifications as examples: Preparation method Example 1: In this embodiment, the diameter of the iron-chromium-aluminum wire is 1.40 mm, and the diameter of the raw material wire rod is 5.50 mm. The drawing temperature is controlled at an ambient temperature of 25°C, eliminating the need for preheating and ensuring that the wire temperature is maintained above 20°C during the drawing process, thus avoiding the brittle zone at room temperature.

[0019] In the first stage of drawing, the wire is drawn from 5.50 mm to 2.80 mm. The reduction rate is calculated as [(5.50÷2)² - (2.80÷2)²] / (5.50÷2)² × 100% = 74.08%, which falls within the 70-90% range. This embodiment selects a reduction rate of 74.08%, which can break up the coarse grains in the cast state and eliminate the original structural defects through sufficient deformation, laying a solid foundation for subsequent homogenization of the structure, while avoiding wire damage caused by excessive deformation. The wire is annealed in a continuous bright annealing furnace at a heating temperature of 850℃, avoiding the 520-800℃ range where brittle phases precipitate. The wire is held at this temperature for 120 seconds in the continuous annealing furnace to ensure complete elimination of work hardening and promote recrystallization. After exiting the furnace, the wire is water-cooled at a rate of 60℃ / second to inhibit abnormal grain growth and brittle phase precipitation, locking in a fine recrystallized structure.

[0020] In the second stage, the wire is drawn from 2.80 mm to 2.00 mm. The area reduction rate is calculated as [(2.80÷2)² - (2.00÷2)²] / (2.80÷2)² × 100% = 48.98%, falling within the range of 45% to 70%. This embodiment selects a reduction rate of 48.98%. While retaining the refinement results of the first stage, this further regularizes the grain morphology, reduces the difference in microstructure between the edges and the center, avoids excessive deformation leading to brittleness, and simultaneously provides a good foundation for the plasticity and toughness of the finished product in the third stage. The steel wire is annealed at a heating temperature of 820℃. The wire is heated and held in the continuous annealing furnace for 100 seconds, and then water-cooled at a rate of 80℃ / second after exiting the furnace to continuously optimize plasticity and toughness.

[0021] The third stage involves drawing the wire from 2.00 mm to 1.40 mm. The reduction rate is calculated as [(2.00÷2)² - (1.40÷2)²] / (2.00÷2)² × 100% = 51%, falling within the 40-65% range. This example uses a reduction rate of 51%, which, while retaining the microstructure refinement results of the first two stages, gently and thoroughly regularizes the internal grains of the wire. This further reduces the microstructure difference between the edge and core, resulting in a more uniform and dense ferrite grain arrangement, without causing a decrease in the wire's plasticity and toughness due to excessive deformation. This provides an ideal microstructure pretreatment state for the subsequent annealing process. The wire is then annealed. The annealing temperature is 850℃, and the wire is heated and held in the continuous annealing furnace for 60 seconds. After exiting the furnace, the wire is water-cooled at a rate of 100℃ / second to completely eliminate residual internal stress and lock in a uniform and fine ferrite structure, meeting the requirements for uniform resistance and winding pitch.

[0022] The processed filament exhibits a fine and uniform microstructure, with no coarse grains in the center, minimal grain size difference between the edges and center, and no brittle precipitates such as δ phase or carbides. Figure 2 As shown, the surface of the wire is smooth and flat, without cracks, scratches, or other defects. After being wound into a resistance wire, as... Figure 4 and Figure 6 As shown, the pitch is uniform and there are no cracks.

[0023] Preparation method Example 2: In this embodiment, the diameter of the iron-chromium-aluminum wire is 1.00 mm, and the diameter of the raw material wire rod is 5.50 mm. The drawing temperature is controlled at an ambient temperature of 25°C, eliminating the need for preheating and ensuring that the wire temperature is maintained above 20°C during the drawing process, thus avoiding the brittle zone at room temperature.

[0024] In the first stage of drawing, the wire is drawn from 5.50 mm to 2.50 mm. The reduction rate is calculated as [(5.50÷2)² - (2.50÷2)²] / (5.50÷2)² × 100% = 79.34%, which falls within the 70-90% large deformation range. This embodiment selects a reduction rate of 79.34%, which is slightly above the middle of the range. This ensures sufficient deformation energy to thoroughly break up the coarse grains in the hot-rolled state, effectively solving the problem of uneven initial microstructure. It also avoids the risk of excessive deformation stress near the 90% upper limit, preventing damage such as scratches on the wire surface and stress concentration inside. Compared to 74.08% in the first stage of Example 1, the reduction rate in this stage is slightly higher, which is suitable for the process requirements of 1.00 mm finished wire. It can more fully eliminate the original microstructure defects and lay a solid foundation for microstructure refinement in subsequent stages. The steel wire is annealed in a continuous bright annealing furnace at a heating temperature of 850℃, avoiding the 520-800℃ range where brittle phases precipitate. The steel wire is heated and held in the continuous annealing furnace for 100 seconds to eliminate internal stress. After exiting the furnace, the steel wire is water-cooled at a rate of 80℃ / second to inhibit grain growth.

[0025] In the second stage, the wire is drawn from 2.50 mm to 1.40 mm. The area reduction rate is calculated as [(2.50÷2)² - (1.40÷2)²] / (2.50÷2)² × 100% = 68.64%, which falls within the 45-70% range. This embodiment uses an area reduction rate of 68.64%, close to the upper limit of the range. Building upon the large deformation process of the first stage, this further enhances the grain fragmentation effect while avoiding excessive deformation that could reduce the wire's toughness. This area reduction rate effectively reduces the grain difference between the edges and center of the wire, improving the uniformity of the microstructure, and provides suitable plasticity and toughness space for the third stage of finished wire drawing. The wire is annealed at 820℃, held in a continuous annealing furnace for 90 seconds, and then water-cooled at a rate of 100℃ / second after exiting the furnace, thus locking in the refined microstructure.

[0026] The third stage involves drawing the wire from 1.40 mm to 1.00 mm. The area reduction rate is calculated as [(1.40÷2)² - (1.00÷2)²] / (1.40÷2)² × 100% = 48.98%, falling within the 40-65% range. This embodiment uses a reduction rate of 48.98%, which is in the lower middle of the range, forming a reasonable gradient with the 68.64% reduction rate in the second stage, thus avoiding microstructural fluctuations caused by abrupt changes in deformation. This area reduction rate gently regulates the internal grains of the wire, preserving the refinement results of the first two stages without sacrificing ductility and toughness due to excessive deformation. The wire is then annealed. The annealing temperature is 820℃, and the wire is held at that temperature in a continuous annealing furnace for 80 seconds. After exiting the furnace, the wire is water-cooled at a rate of 100℃ / second, effectively eliminating residual stress, thoroughly optimizing the microstructure, and ensuring the quality of the finished product.

[0027] After processing, the finished filament exhibits fine and uniform grains, with no localized coarse grains. Figure 2 As shown, the surface of the wire is highly smooth, free from defects such as cracks and inclusions. Figure 4 and Figure 6 As shown, there was no breakage or deformation during the winding process.

[0028] Preparation method Example 3: In this embodiment, the diameter of the iron-chromium-aluminum wire is 0.80 mm, and the diameter of the raw material wire rod is 5.50 mm. The drawing temperature is controlled at an ambient temperature of 25°C, eliminating the need for preheating and ensuring that the wire temperature is maintained above 20°C during the drawing process, thus avoiding the brittle zone at room temperature.

[0029] In the first stage of drawing, the wire is drawn from 5.50 mm to 2.00 mm. The reduction rate is calculated as [(5.50÷2)² - (2.00÷2)²] / (5.50÷2)² × 100% = 86.78%, which is in the 70-90% range, close to the upper limit of 90%. This embodiment uses this high reduction rate because it is designed for the special needs of ultra-fine wire. By maximizing the deformation, the original coarse grains can be broken up more thoroughly, and even the grain boundaries can be disintegrated, laying a solid foundation for the uniformity of the microstructure of the ultra-fine wire. At the same time, this value does not exceed the upper limit of 90%, which can avoid irreversible damage to the wire due to excessive deformation. The wire is then annealed at a heating temperature of 820℃. The wire is heated and held in the continuous annealing furnace for 100 seconds to ensure sufficient recrystallization and avoid the precipitation of brittle phases. After exiting the furnace, the wire is water-cooled at a rate of 80℃ / second to quickly lock in the fine recrystallized structure, improve the ductility and toughness of the wire, and meet the requirements of subsequent fine drawing.

[0030] In the second stage, the wire is drawn from 2.00 mm to 1.20 mm. The area reduction rate is calculated as [(2.00÷2)² - (1.20÷2)²] / (2.00÷2)² × 100% = 64%, falling within the 45-70% range. This embodiment uses a 64% area reduction rate, which is in the upper-middle range. Following the high deformation process of the first stage, this further refines the grains, continuously optimizes the uniformity of the microstructure, and precisely controls the deformation intensity, avoiding an increased risk of brittle fracture in the ultrafine wire due to excessive deformation. This area reduction rate balances the microstructure refinement effect with the wire's toughness, providing stable microstructure support for the third stage of ultrafine wire drawing. The wire is annealed at 820°C, held at that temperature in a continuous annealing furnace for 80 seconds, and then water-cooled at a rate of 100°C / second after exiting the furnace. This continuously optimizes the uniformity of the microstructure and reduces the risk of brittle fracture in the ultrafine wire.

[0031] The third stage involves drawing the wire from 1.20 mm to a finished product of 0.80 mm. The area reduction rate is calculated as [(1.20÷2)² - (0.80÷2)²] / (1.20÷2)² × 100% = 55.55%, falling within the 40-65% range. This embodiment uses a reduction rate of 55.55%, which is in the middle of the range and suits the final drawing requirements of ultra-fine finished products. This not only further regulates the grain arrangement through moderate deformation, reducing the difference in structure between the edge and the core, but also avoids excessive deformation that could cause scratches on the wire surface or residual internal stress. The wire is then annealed at 820°C. The wire is heated and held in the continuous annealing furnace for 60 seconds, and then water-cooled at a rate of 120°C / second after exiting the furnace. This process completely eliminates residual internal stress, locks in a fine and uniform ferrite structure, and ensures that the wire does not crack or deform during winding, meeting the stringent requirements for ultra-fine wire specifications.

[0032] The processed filament exhibits excellent uniformity in its microstructure, with fine and consistent grain size and no microscopic defects. Figure 2 As shown, the surface of the silk is smooth and flawless, without cracks, scratches or other defects, such as... Figure 4 and Figure 6 As shown, the pitch is uniform and there are no cracks.

[0033] like Figure 1 , Figure 3 and Figure 5 As shown, the traditional process has a low surface smoothness of the wire material, with defects such as cracks and inclusions. The winding pitch is uneven and there are breakage and deformation phenomena during the winding process, which is in stark contrast to the effects of Example 1, Example 2 and Example 3.

[0034] like Figure 7 As shown, the fewer defects in the wire, the more uniform the resistance value.

[0035] The specific operating procedure is as follows: The processing conditions are adjusted according to the ambient temperature. Drawing operations are carried out above 20℃. In winter, the raw material wire rod needs to be preheated to ensure that the material is within its toughness temperature range, thus preparing it for drawing. Then, a three-stage segmented drawing process is initiated: In the first stage, a large deformation is used to fully break down the coarse grains in the hot-rolled state, eliminating original structural defects. After drawing, the wire is fed into a continuous bright annealing furnace and held at a specific temperature for a certain duration to eliminate work hardening and internal stress, promoting recrystallization. Immediately after annealing, rapid water cooling is performed to inhibit grain growth and brittle phase precipitation, enhancing the material's ductility and toughness. The second stage of drawing then uses a moderate deformation to further refine the microstructure, reducing grain differences between the edges and the center. The annealing and water cooling steps are repeated to ensure continuous optimization of microstructure uniformity. Finally, the wire is processed to the target specifications through the third stage of drawing, completing the final annealing and water cooling treatment, fixing the uniform and fine recrystallized microstructure, and ultimately obtaining a defect-free, uniformly performing iron-chromium-aluminum wire product.

[0036] This application solves the brittle fracture problem in the drawing process of iron-chromium-aluminum wire by synergistically combining temperature control, segmented deformation, and precise annealing. The resulting product surface is free of cracks and other defects, significantly improving the production yield. The three-stage drawing process combined with staged annealing promotes a finer and more uniform wire microstructure, eliminating coarse grains in the center and greatly reducing the microstructure difference between the edges and the center, laying a solid foundation for uniform performance. The product exhibits uniform resistance distribution, and the pitch remains consistent after winding into resistance wire, avoiding heating efficiency fluctuations caused by performance inconsistencies and improving the reliability of end-use equipment.

[0037] It should be noted that, unless otherwise expressly specified and limited, the term "connection" or its synonyms should be interpreted broadly in this document. For example, "connection" can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, expressions such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. At the same time, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In addition, the terms "front," "rear," "left," "right," "upper," and "lower" in this document refer to the placement states shown in the accompanying drawings.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing electrothermal alloy iron-chromium-aluminum wire with improved performance uniformity, characterized in that, Includes the following steps: Step S1: Drawing temperature control, the drawing temperature of the iron-chromium-aluminum raw material wire rod is always maintained above 20℃; Step S2: First stage drawing and annealing. The first stage drawing is carried out on the raw material wire rod. The drawing reduction rate is 70-90%. After the drawing is completed, annealing is carried out. After annealing, the steel wire is quickly sent to the water cooling section for cooling. Step S3: Second stage drawing and annealing. The steel wire treated in step S2 is drawn in the second stage with a reduction in surface area of ​​45-70%. After drawing, annealing is performed. After annealing, the steel wire is quickly sent to the water cooling section for cooling. Step S4: Third stage drawing and annealing. The steel wire treated in step S3 is drawn in the third stage with a reduction in surface area of ​​40-65%. After drawing to the finished product specifications, it is annealed. After annealing, the steel wire is quickly sent to the water cooling section for cooling, thereby obtaining iron-chromium-aluminum wire with uniform properties.

2. The preparation method for improving the uniformity of the properties of electrothermal alloy iron-chromium-aluminum wire according to claim 1 is characterized in that the annealing process in steps S2, S3 and S4 is carried out in a continuous bright annealing furnace.

3. The preparation method for improving the uniformity of the properties of electrothermal alloy iron-chromium-aluminum wire according to claim 2 is characterized in that the annealing process parameters in steps S2, S3 and S4 are in the same range, the annealing heating temperature is 820-850℃ and the heating and holding time is 60-120 seconds.

4. The preparation method for improving the uniformity of the properties of electrothermal alloy iron-chromium-aluminum wire according to claim 1 is characterized in that, during the water cooling process in steps S2, S3 and S4, the cooling rate range is 50 to 200°C / second.

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