Tensile titanium alloy wire processing technology

Abstract

The application relates to the technical field of titanium material manufacturing, in particular to a tensile titanium alloy wire processing technology, which comprises the following steps: placing aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen and titanium into a vacuum self-consumption arc furnace according to proportions to perform smelting, so as to obtain a titanium alloy ingot; performing heating forging on the titanium alloy ingot after chemical cleaning; performing rolling and drawing on the forged blank, and performing annealing treatment on the drawn wire; collecting the temperature of each position in each temperature region of a continuous annealing furnace at each time point, determining the thermal diffusion fluctuation degree of each position in each time period in the continuous annealing furnace; calculating the heat flow coefficient of each position in each time period in the continuous annealing furnace; obtaining the proportional parameter of a PID controller of each position in each time period in the continuous annealing furnace, and controlling the temperature of each position by using the PID controller; and obtaining the titanium alloy wire after the annealing treatment. The application improves the tensile property of the titanium alloy wire.

Description

Technical Field

[0001] This application relates to the field of titanium material manufacturing technology, specifically to a tensile titanium alloy wire processing technology. Background Technology

[0002] Titanium alloy wire is a crucial basic material in the manufacturing of titanium materials, widely used in aerospace, medical, and other fields. Titanium alloy wire can be processed into various precision shapes and sizes to meet the specific requirements of different fields for material form and performance. Especially in industries with high precision requirements such as aerospace, the processing of titanium alloy wire can provide the necessary dimensional accuracy and stable performance.

[0003] In the annealing process of titanium alloy wire, a continuous annealing furnace is usually used to process the metal wire. The traditional method is to use a PID algorithm with fixed parameters to control the temperature of different areas of the annealing furnace. However, due to the existence of heat diffusion, heat will flow from the high-temperature area to the low-temperature area during the annealing process. The traditional fixed-parameter PID control fails to fully consider the phenomenon of heat diffusion during the annealing process, resulting in poor annealing effect of titanium alloy wire and the problem of reduced tensile strength of titanium alloy wire. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a tensile titanium alloy wire processing technology to solve the existing issues.

[0005] The technical solution for processing tensile-strength titanium alloy wire in this application is as follows:

[0006] One embodiment of this application provides a process for processing tensile-resistant titanium alloy wire, the process including:

[0007] Aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen, and titanium are placed in a vacuum arc furnace in a certain proportion for melting to obtain titanium alloy ingots; the chemically cleaned titanium alloy ingots are then heated and forged.

[0008] The forged billet is rolled and drawn, and the drawn wire is annealed in a continuous annealing furnace.

[0009] The temperature at each location in each temperature zone of the continuous annealing furnace is collected at each time. The temperature zones in the continuous annealing furnace are arranged in sequence as preheating zone, heating zone, soaking zone, and cooling zone.

[0010] Analyze the temperature differences between each location and its neighboring locations at each time point to determine the heat loss rate at each location at each time point; based on the temperature difference between each location and the target temperature at each time point within each preset time period, and in conjunction with the heat loss rate, determine the heat diffusion fluctuation rate of each location within each time period.

[0011] For the preheating zone and the heating zone, the heat flow coefficient of each location in the preheating zone and the heating zone in each time period is determined by the difference in heat diffusion fluctuation between each location and all locations to its left in each time period.

[0012] For the heat spreader and cooling zone, the heat flow coefficient of each location in the heat spreader and cooling zone is determined by the difference in heat diffusion fluctuation between each location in each time period and a set location in the same temperature zone.

[0013] Based on the heat flow coefficient of each location in each time period and the previous time period, and combined with the proportional parameters of the PID controller of each location in the previous time period, the proportional parameters of the PID controller of each location in each time period are determined, and the temperature of each location is controlled by the PID controller.

[0014] Titanium alloy wire is obtained after annealing.

[0015] In one embodiment, the ratio of aluminum, vanadium, iron, carbon, nitrogen, hydrogen, and oxygen is:

[0016] Aluminum is 5.5-6.8%, vanadium is 3.5-4.5%, iron is ≤0.30%, carbon is ≤0.08%, nitrogen is ≤0.05%, hydrogen is ≤0.015%, oxygen is ≤0.20%, and the balance is titanium raw material.

[0017] In one embodiment, the maximum melting current of the vacuum arc furnace is 1500A, the operating voltage is 20-45V, and the operating vacuum degree is 1×10⁻⁶. -1 Pa~10 -2 Pa.

[0018] In one embodiment, the chemical cleaning involves first using a grinding wheel to remove oxide scale, inclusions, and surface defects from the surface of the titanium alloy ingot, and then chemically cleaning the titanium alloy ingot with hydrofluoric acid.

[0019] In one embodiment, the temperature of the heated casting is 900℃~1200℃; the temperature of the rolling is 800℃~1100℃; and the drawing is performed by drawing 10~15 times using a wire drawing machine to make the final wire diameter ≤0.5mm.

[0020] In one embodiment, the temperature of the preheating zone is 400℃~500℃, the temperature of the heating zone is 750℃~900℃, the temperature of the heat spreader zone is 750℃~900℃, and the cooling zone is subjected to isothermal annealing, followed by air cooling after holding at 600℃~650℃.

[0021] In one embodiment, determining the degree of heat loss includes:

[0022] Obtain the location corresponding to the maximum temperature among all locations at each time point, and record it as the maximum location;

[0023] For each moment, if any position is to the left of the maximum position, calculate the temperature difference between the left adjacent position and the position and the position, and record it as the first difference. Calculate the temperature difference between the position and the right adjacent position, and record it as the second difference. The heat loss of any position at each moment is the sum of the first difference and the second difference.

[0024] Otherwise, calculate the temperature difference between the right adjacent position and the location of any given position, and record it as the third difference. Calculate the temperature difference between the location of any given position and its left adjacent position, and record it as the fourth difference. The heat loss of any given position at each time moment is the sum of the third difference and the fourth difference.

[0025] In one embodiment, determining the thermal diffusion fluctuation includes:

[0026] For each location, the difference between the temperature and the target temperature at each time within each time period is calculated and recorded as the fifth difference. The absolute value of the sum of the fifth difference and the heat loss at each time at each location is calculated. The heat diffusion fluctuation is the average of the absolute values ​​at all times within each time period at each location.

[0027] In one embodiment, determining the heat flow coefficient at each location in the preheating and heating zones over each time period includes:

[0028] For each time period, if any position is located in the preheating zone or the heating zone, the difference between the thermal diffusion fluctuation of the position and each position to its left is calculated and recorded as the sixth difference. The sum of the sixth differences between the position and each position to its left is calculated, and the heat flow coefficient of the position in each time period is the normalized value of the sum.

[0029] The determination of the heat flow coefficient of each location in the heat homogenization zone and the cooling zone in each time period includes: if any location is located in the heat homogenization zone, then calculate the difference in heat diffusion fluctuation between any location and each location in the heat homogenization zone, which is recorded as the seventh difference. The heat flow coefficient of any location in each time period is the normalized value of the sum of the seventh differences between any location and all locations in the heat homogenization zone.

[0030] If any of the positions is located in the cooling zone, the difference between the thermal diffusion fluctuation of each position to the right of the position and that of the position is calculated and recorded as the eighth difference. The heat flow coefficient of the position in each time period is the normalized value of the sum of the eighth difference between the position to the right of the position and that of the position.

[0031] In one embodiment, the proportional parameter of the PID controller at each location and time period is determined by the following expression:

[0032] In the formula, K p,x K represents the proportional parameter of the PID controller at position x in each time period. p,x ' is the proportional parameter of the PID controller at position x in the previous time period, sr x Let sr be the heat flow coefficient at location x in each time period. x ′ is the heat flow coefficient of the x-th position in the previous time period.

[0033] This application has at least the following beneficial effects:

[0034] This application calculates the thermal diffusion fluctuation at each location within a continuous annealing furnace over various time periods, enabling precise quantification of temperature fluctuations at each location at different times. This helps to clearly understand the temperature stability of each region, thus allowing for more accurate temperature control of the annealing furnace. Furthermore, by determining the heat flow coefficient at each location within the continuous annealing furnace over various time periods, the application reflects the heat flow from high-temperature to low-temperature regions, demonstrating the temperature stability at each location and improving the accuracy and reliability of subsequent temperature control. Using the heat flow coefficient, the application determines the proportional parameters of the PID controller at each location and time period, and then uses the PID controller to control the temperature at each location, achieving the desired annealing temperature. The adaptive adjustment of the temperature field inside the furnace helps the PID controller to respond quickly to temperature deviations and improve annealing uniformity. Compared with traditional fixed-parameter PID control, this application can dynamically adjust the control strategy according to actual temperature fluctuations, avoiding unsatisfactory annealing effects caused by temperature fluctuations, thereby significantly improving the accuracy of temperature control. Stable temperature control is conducive to the uniform generation and distribution of primary and secondary α phases in titanium alloy wire. The content and distribution of primary and secondary α phases play a key role in the tensile strength and other performance indicators of titanium alloy wire. By optimizing the crystallization process, the microstructure of titanium alloy wire is made more uniform, thereby effectively improving the tensile strength of titanium alloy wire, reducing performance fluctuations caused by temperature fluctuations, and improving the finished product quality of titanium alloy wire. Attached Figure Description

[0035] To more clearly illustrate the technical solutions and advantages 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A flowchart of the processing steps for tensile titanium alloy wire provided in this application;

[0037] Figure 2 This is a schematic diagram showing the temperature zones and temperature sensor distribution in a continuous annealing furnace.

[0038] Figure 3 Flowchart for determining the proportional parameters of a PID controller. Detailed Implementation

[0039] To further illustrate the technical means and effects adopted by this application to achieve the intended purpose of the invention, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a tensile titanium alloy wire processing technology proposed in this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0041] The following description, in conjunction with the accompanying drawings, details a specific scheme for the processing technology of tensile titanium alloy wire provided in this application.

[0042] Example 1

[0043] Please see Figure 1 It shows a flowchart of the processing steps of a tensile titanium alloy wire according to Embodiment 1 of this application, the process including:

[0044] S1: Aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen, and titanium are placed in a vacuum arc furnace in proportion for smelting to obtain titanium alloy ingots.

[0045] Aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen, and titanium are smelted in a vacuum arc remelting furnace according to the specified proportions. In this embodiment, aluminum (Al) is 5.5%, vanadium (V) is 3.5%, iron (Fe) ≤0.30%, carbon (C) ≤0.08%, nitrogen (N) ≤0.05%, hydrogen (H) ≤0.015%, and oxygen (O) ≤0.20%. Alternatively, iron (Fe) is 0.2%, carbon (C) is 0.06%, nitrogen (N) is 0.03%, hydrogen (H) is 0.013%, and oxygen (O) is 0.18%, with the balance being titanium (Ti). The maximum smelting current of the vacuum arc remelting furnace is 1500A; the operating voltage is 20–45V; and the ultimate vacuum degree is 1.33 × 10⁻⁶.-2 Pa, working vacuum degree: 1×10 -1 Pa~10 -2 Pa, all raw materials are melted and solidified into ingots by electric arc melting in a high vacuum environment, thus realizing the preparation of titanium alloy ingots in titanium material manufacturing.

[0046] S2: The chemically cleaned titanium alloy ingot is heated and forged.

[0047] For titanium alloy ingots smelted in S1, natural cooling is used. After cooling, the ingots are first cleaned by using a grinding wheel to remove oxide scale, inclusions, and surface defects. Then, the ingots are chemically cleaned with hydrofluoric acid.

[0048] The chemically cleaned titanium alloy ingot is heated to 900°C using electric heating, and then forged into a titanium rod with a diameter of 5mm using a press.

[0049] S3: Rolling and drawing the forged billet.

[0050] The forged billet is heated to a rolling temperature of 800℃ and held for 5 minutes to ensure uniform temperature. The billet is then rolled into coiled wire blanks using a rolling mill.

[0051] The rolled wire blank is pickled to remove the surface oxide layer and defects. Then, the surface of the wire blank is pre-oxidized to form a protective film. The wire blank is then drawn 10 times through a wire drawing machine, gradually reducing the diameter to ≤0.5mm.

[0052] S4: The drawn wire is annealed in a continuous annealing furnace.

[0053] The drawn wire is annealed, specifically in a continuous annealing furnace. The furnace includes four temperature zones: a preheating zone, a heating zone, a soaking zone, and a cooling zone. The preheating zone has a temperature range of 400℃–500℃, the heating zone 750℃–900℃, and the soaking zone 750℃–900℃. After complete annealing, the wire is slowly cooled. Isothermal annealing is performed in the cooling zone, holding at 600℃–650℃ followed by air cooling. This application controls the temperature of each zone during the annealing process, specifically as follows:

[0054] S401: Collect the temperature of each location in each temperature zone of the continuous annealing furnace at each time.

[0055] In this embodiment, for each temperature zone in the continuous annealing furnace—namely, the preheating zone, the heating zone, the soaking zone, and the cooling zone—four temperature sensors are evenly distributed in each temperature zone. Each temperature sensor corresponds to a specific position within its assigned temperature zone, resulting in a total of 16 temperature sensors installed in the continuous annealing furnace. Since the temperature zones in the continuous annealing furnace are arranged in the order of preheating zone, heating zone, soaking zone, and cooling zone, the position numbers of each temperature sensor can be obtained by following the left-to-right arrangement. A schematic diagram of the temperature zones and temperature sensor distribution in the continuous annealing furnace is shown below. Figure 2 As shown.

[0056] Then, temperature sensors are used to collect the temperature of titanium alloy wire at various locations within different temperature zones of the continuous annealing furnace during annealing. The collection frequency is 100Hz, and the collection period is 2 seconds. The implementer can set this frequency according to actual conditions; this embodiment does not impose any limitations. One collection period is considered a time period. The temperature data collected by each temperature sensor is denoised using a mean filter. The denoised temperature data for each location and time period are then arranged in chronological order of collection time to obtain the annealing temperature sequence for each location and time period. Mean filtering is a well-known existing technique, and its specific process will not be elaborated upon. The implementer can choose other feasible filtering algorithms; this embodiment does not impose any limitations.

[0057] S402: Analyze the temperature difference between each location and its adjacent locations at each time to determine the heat loss at each location at each time; based on the temperature difference between each location and the target temperature at each time within each preset time period, and in conjunction with the heat loss, determine the heat diffusion fluctuation of each location in each time period.

[0058] In a continuous annealing furnace, heat is transferred from the high-temperature region to the low-temperature region, causing the temperature of the low-temperature region to rise. Since the temperature regions at the two ends of the continuous annealing furnace are the preheating region and the cooling region, respectively, the temperature at both ends is the lowest, and the temperature in the middle is the highest. Therefore, heat diffuses from the middle to both ends in the continuous annealing furnace. Thus, this embodiment obtains the maximum temperature at all positions at each moment, and the position number corresponding to the maximum value is recorded as the maximum position G.

[0059] It should be noted that if there are multiple maximum values ​​for the temperature at all locations at any given time, the average of the location indices corresponding to these multiple maximum values ​​is recorded as the maximum location G.

[0060] Therefore, in order to analyze the thermal diffusivity of temperature at different locations in a continuous annealing furnace, this embodiment determines the heat loss at each location at each time point based on the temperature difference between each location and its adjacent locations. The specific calculation method is as follows:

[0061] Cl j =(T j-1 -T j )+(T j -T j+1 ), j <G

[0062] Cl i =(T i+1 -T i )+(T i -T i-1 ), i≥G

[0063] In the formula, Cl j Cl i T represents the heat loss at the j-th and i-th positions at different times in the continuous annealing furnace, respectively. j+1 T j T j-1 T represents the temperature at the (j+1)th, jth, and (j-1)th positions in the continuous annealing furnace at various times. i-1 T i T i+1 Let T represent the temperatures at the (i-1), ith, and (i+1)th positions at various times in the continuous annealing furnace. j-1 -T j Let (T) be the first difference. For the j-th position, the (j-1)-th position is the left adjacent position of the j-th position; j -T j+1 Let (T) be the second difference. For the j-th position, the (j+1)-th position is the right-side adjacent position of the j-th position; i+1 -T i Let (T) be the third difference. For the i-th position, the (i+1)-th position is the right-side adjacent position of the i-th position; i -T i-1 Let ) be the fourth difference. For the i-th position, the (i-1)-th position is the left adjacent position of the i-th position.

[0064] It should be noted that when j-1 = 0, let T j-1 =T j When i = N, let T i+1 =T i In this embodiment, N=16, which represents the number of temperature sensors in the continuous annealing furnace. The temperature difference represents the degree of difference between two temperatures, which can be calculated using methods such as difference, ratio, or absolute value of the difference. This embodiment does not impose any restrictions on this.

[0065] It should be understood that in a continuous annealing furnace, due to heat diffusion, high-temperature areas transfer heat to low-temperature areas, resulting in heat loss. The greater the temperature difference between each location and its adjacent locations, the greater the total heat loss. Therefore, the degree of heat loss directly reflects the heat loss at each location. A greater degree of heat loss indicates more significant heat loss at that location. In the manufacturing process of titanium alloy wire, it is necessary to maintain temperature stability and reduce heat loss at each location to promote the formation of crystals in the titanium alloy wire, thereby improving its tensile strength.

[0066] During the annealing process of titanium alloy wire, it is crucial to maintain temperature stability at each stage. Unstable temperatures affect the content and distribution of primary and secondary α-phases in the titanium alloy, thereby reducing the tensile strength of the wire. Furthermore, unstable temperatures can cause fluctuations in properties such as hardness and reduction of area, leading to quality issues. Due to thermal diffusion, continuous annealing furnaces cause temperature variations across different temperature zones. Fluctuations in thermal diffusion indicate that the temperatures in different zones of the continuous annealing furnace cannot be kept balanced. The greater the fluctuations in thermal diffusion, the more uneven the tensile strength of the produced titanium alloy wire, resulting in a decrease in overall tensile strength.

[0067] Therefore, in this embodiment, the target temperature of each position in each temperature zone of the continuous annealing furnace is first set. For the heat homogenization zone, the target temperature of all positions is set to 500°C. For the heating zone and the heat homogenization zone, the target temperature of all positions is set to 840°C. For the cooling zone, the target temperature of all positions is set to 600°C. The implementer can set the target temperature of all positions according to the actual situation. This embodiment does not impose any restrictions on this.

[0068] Based on the temperature difference between each location and the target temperature at each time point within each preset time period, and combined with the heat loss rate, the heat diffusion fluctuation of each location within each time period is calculated. The specific calculation method is as follows:

[0069] In the formula, PF x ht represents the thermal diffusion fluctuation at the x-th position in a continuous annealing furnace over various time periods. x,y H represents the temperature at position x in a continuous annealing furnace at time y within any time period. x CL represents the target temperature at the x-th position in the continuous annealing furnace. x,y Let be the heat loss at position x in a continuous annealing furnace at time y in any time period, and m be the number of times within each time period. (ht) x,y -Hx This is denoted as the fifth difference.

[0070] It should be understood that, ideally, the annealing temperature of titanium alloy wire in a continuous annealing furnace should be the same at different times for the same location. A greater variation in heat loss indicates that the continuous annealing furnace cannot guarantee temperature stability. Drastic temperature fluctuations interfere with the phase transformation and crystallization processes of the titanium alloy during annealing, reducing the amount of primary and secondary α-phase crystals formed in the titanium alloy wire, resulting in an uneven microstructure. The reduction in primary and secondary α-phase directly affects the tensile strength of the titanium alloy wire, causing a decrease in its tensile strength.

[0071] S403: For the preheating zone and the heating zone, the heat flow coefficient of each position in the preheating zone and the heating zone in each time period is determined by the difference in heat diffusion fluctuation between each position in each time period and all positions to its left; for the heat homogenization zone and the cooling zone, the heat flow coefficient of each position in the heat homogenization zone and the cooling zone in each time period is determined by the difference in heat diffusion fluctuation between each position in each time period and a set position in the same temperature zone.

[0072] Different temperature zones in a continuous annealing furnace have different effects on titanium alloy wires. The preheating and heating zones heat the titanium alloy wires. Due to the continuous movement of the titanium alloy, the heating time varies in different zones, thus requiring different temperatures. The closer to the homogenization zone, the higher the temperature of the titanium alloy wire, and the less heat it needs to absorb. The homogenization zone has the highest heat output, leading to heat flow from it to other temperature zones. To assess this heat flow phenomenon in different temperature zones, this embodiment calculates the heat flow coefficient at each location in the continuous annealing furnace at each time period based on the difference in heat diffusion fluctuations between each location and its neighboring locations. The specific calculation method is as follows:

[0073]

[0074]

[0075]

[0076] In the formula, sr x PF represents the heat flow coefficient at the x-th position in a continuous annealing furnace during various time periods. x PF represents the thermal diffusion fluctuation at the x-th position in a continuous annealing furnace over various time periods. kdenotes the thermal diffusion fluctuation degree of the k-th position in the continuous annealing furnace at each time period. Both x and k represent the serial numbers of each position in the continuous annealing furnace. NORM() represents the normalization function, and N is the number of temperature sensors in the continuous annealing furnace. When x ≤ 8, it indicates that the x-th position is in the preheating area or the heating area. When 8 < x ≤ 12, it indicates that the x-th position is in the soaking area. When x > 12, it indicates that the x-th position is in the cooling area. Denote (PF x -PF k ) as the sixth difference, (PF x -PF k ) as the seventh difference, and (PF k -PF x ) as the eighth difference.

[0077] It should be understood that for the same position in the continuous annealing furnace, in an ideal state, the heat flow should remain stable, that is, the thermal diffusion fluctuation degree should be zero. However, in the actual process, the thermal diffusion fluctuation degree of each position is often not zero. Since the titanium alloy wire exists in the annealing furnace for different times at different positions during the annealing process, the heat absorbed is also different, resulting in different change states of the heat flow in different temperature regions. Since the temperature in the soaking area is the highest, the heat flows from the soaking area to the temperature regions on both sides. That is, the heat in the soaking area will flow to the heating area and the preheating area, and also to the cooling area. For the preheating area and the heating area, in each time period, if the difference between the thermal diffusion fluctuation degree of the x-th position and that of all positions on its left is larger, it indicates that the x-th position is more likely to have heat flow to its left position. Therefore, the heat flow coefficient of the x-th position is larger. For the soaking area, since the soaking area is the area with the highest temperature in the continuous annealing furnace, when analyzing the heat flow of each position in the soaking area, only consider the thermal diffusion fluctuation degree of the adjacent positions within the soaking area. If the difference between the thermal diffusion fluctuation degree of the x-th position and that of all positions on its left within the soaking area is larger, it means the possibility of heat flow is greater. For the cooling area, if the difference between the thermal diffusion fluctuation degree of all positions on the right of the x-th position and that of the x-th position is larger, it indicates that the heat in the high-temperature area is more likely to flow to the low-temperature area, and the heat flow coefficient is larger, reflecting that the temperature in the continuous annealing furnace is more unstable, with larger fluctuations, and temperature control needs to be enhanced to better produce titanium alloy wire with higher tensile strength.

[0078] S404: Based on the heat flow coefficients of each position at each time period and its previous time period, combined with the proportional parameters of the PID controller of each position in the previous time period, determine the proportional parameters of the PID controller of each position at each time period, and use the PID controller to control the temperature of each position.

[0079] When the temperature stability in the annealing furnace for producing titanium alloy wire decreases continuously, i.e., the heat flow coefficient at each location within the continuous annealing furnace increases over time, it indicates that the PID controller in the furnace is not effectively controlling the temperature. During this process of decreasing temperature stability, it is necessary to increase the parameters of the PID controller to ensure stable processing of the titanium alloy wire. Therefore, this embodiment determines the proportional parameters of the PID controller at each location within the continuous annealing furnace over each time period, expressed as follows:

[0080] In the formula, K p,x K represents the proportional parameter of the PID controller at position x in each time period. p,x ' is the proportional parameter of the PID controller at position x in the previous time period, sr x Let sr be the heat flow coefficient at location x in each time period. x ′ is the heat flow coefficient of the x-th position in the previous time period.

[0081] It should be understood that if the heat flow coefficient at any point in the current continuous annealing furnace is larger, it indicates that the temperature stability is reduced. Therefore, it is necessary to increase the proportional parameter of the PID controller so that it can be quickly adjusted when an error occurs, so that the temperature is kept within a small error range, thereby improving the accuracy of temperature control.

[0082] The integral and derivative parameters of a PID controller are calculated as follows:

[0083] K i,x =K p,x / T i K d,x =K p,x ×T d , where K i,x Let T be the integral parameter of the PID controller at position x in each time period. i K represents the integration time. d,x Let T be the differential parameter of the PID controller at position x in each time period. d This represents the differential time. The calculation of the integral time and differential time is a well-known technique and will not be elaborated upon here.

[0084] Therefore, the PID controllers at various locations in the continuous annealing furnace use calculated proportional, integral, and derivative parameters to control and adjust the error between the actual and target temperatures within the furnace, thus maintaining the furnace temperature at the target level. The flowchart for determining the PID controller's proportional parameters is as follows: Figure 3 As shown.

[0085] S5: Titanium alloy wire obtained after annealing.

[0086] After annealing, titanium alloy wire is obtained. High-precision measuring equipment is used to inspect the diameter, ellipticity, and other dimensional parameters of the titanium alloy wire to ensure compliance with standard requirements. In this embodiment, a micrometer is used as the high-precision measuring equipment; however, the implementer can choose other existing high-precision measuring equipment, such as a diameter gauge.

[0087] Example 2

[0088] Please see Figure 1 It shows a flowchart of the processing steps of a tensile titanium alloy wire according to Embodiment 2 of this application, the process including:

[0089] S1: Aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen, and titanium are placed in a vacuum arc furnace in proportion for smelting to obtain titanium alloy ingots.

[0090] Aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen, and titanium are smelted in a vacuum arc remelting furnace according to the specified proportions. In this embodiment, aluminum (Al) is 6.0%, vanadium (V) is 4.0%, iron (Fe) ≤0.30%, carbon (C) ≤0.08%, nitrogen (N) ≤0.05%, hydrogen (H) ≤0.015%, and oxygen (O) ≤0.20%. Alternatively, iron (Fe) is 0.25%, carbon (C) is 0.07%, nitrogen (N) is 0.04%, hydrogen (H) is 0.014%, and oxygen (O) is 0.19%, with the balance being titanium (Ti). The maximum smelting current of the vacuum arc remelting furnace is 1500A; the operating voltage is 20–45V; and the ultimate vacuum degree is 1.33 × 10⁻⁶. -2 Pa, working vacuum degree: 1×10 -1 Pa~10 -2 Pa, all raw materials are melted and solidified into ingots by electric arc melting in a high vacuum environment, thus realizing the preparation of titanium alloy ingots in titanium material manufacturing.

[0091] S2: The chemically cleaned titanium alloy ingot is heated and forged.

[0092] For titanium alloy ingots smelted in S1, natural cooling is used. After cooling, the ingots are first sandblasted to remove oxide scale, inclusions, and surface defects. Then, the ingots are chemically cleaned with nitric acid.

[0093] The chemically cleaned titanium alloy ingot is heated to 1000°C using electric heating, and then forged into a titanium rod with a diameter of 10mm using a press.

[0094] S3: Rolling and drawing the forged billet.

[0095] The forged billet is heated to a rolling temperature of 1000℃ and held for 8 minutes to ensure uniform temperature. The billet is then rolled into coiled wire blanks using a rolling mill.

[0096] The rolled wire blank is pickled to remove the surface oxide layer and defects. Then, the surface of the wire blank is pre-oxidized to form a protective film. The wire blank is then drawn 13 times through a wire drawing machine, gradually reducing the diameter to ≤0.5mm.

[0097] The remaining steps are performed exactly the same as those in Embodiment 1 of this application to obtain titanium alloy wire.

[0098] Example 3

[0099] Please see Figure 1 It shows a flowchart of the processing steps of a tensile titanium alloy wire according to Embodiment 3 of this application, the process including:

[0100] S1: Aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen, and titanium are placed in a vacuum arc furnace in proportion for smelting to obtain titanium alloy ingots.

[0101] Aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen, and titanium are smelted in a vacuum arc remelting furnace according to the specified proportions. In this embodiment, aluminum (Al) is 6.8%, vanadium (V) is 4.5%, iron (Fe) ≤0.30%, carbon (C) ≤0.08%, nitrogen (N) ≤0.05%, hydrogen (H) ≤0.015%, and oxygen (O) ≤0.20%. Alternatively, iron (Fe) is 0.3%, carbon (C) is 0.08%, nitrogen (N) is 0.05%, hydrogen (H) is 0.015%, and oxygen (O) is 0.20%, with the balance being titanium (Ti). The maximum smelting current of the vacuum arc remelting furnace is 1500A; the operating voltage is 20–45V; and the ultimate vacuum degree is 1.33 × 10⁻⁶. -2 Pa, working vacuum degree: 1×10 -1 Pa~10 -2 Pa, all raw materials are melted and solidified into ingots by electric arc melting in a high vacuum environment, thus realizing the preparation of titanium alloy ingots in titanium material manufacturing.

[0102] S2: The chemically cleaned titanium alloy ingot is heated and forged.

[0103] For titanium alloy ingots smelted in S1, natural cooling is used. After cooling, the ingots are first cleaned by using a grinding wheel to remove oxide scale, inclusions, and surface defects. Then, the ingots are chemically cleaned with hydrofluoric acid.

[0104] The chemically cleaned titanium alloy ingot is heated to 1200℃ using electric heating, and then forged into a titanium rod with a diameter of 15mm using a press.

[0105] S3: Rolling and drawing the forged billet.

[0106] The forged billet is heated to a rolling temperature of 1100℃ and held for 10 minutes to ensure uniform temperature. The billet is then rolled into coiled wire blanks using a rolling mill.

[0107] The rolled wire blank is pickled to remove the surface oxide layer and defects. Then, the surface of the wire blank is pre-oxidized to form a protective film. The wire blank is then drawn 15 times through a wire drawing machine, gradually reducing the diameter to ≤0.5mm.

[0108] The remaining steps are performed exactly the same as those in Embodiment 1 of this application to obtain titanium alloy wire.

[0109] Comparative Example 1

[0110] The titanium alloy wire was processed according to the exact same steps and parameters as in Embodiment 1 of this application. The difference was that the proportional parameter of the PID controller at each position of the continuous annealing furnace was set to a fixed value of 15, and the integral and derivative parameters were set according to K. i,x =K p,x / T i K d,x =K p,x ×T d Calculations are performed to obtain the parameters of the PID controller, which controls the temperature at each location in the continuous annealing furnace at each time period, and finally processes the titanium alloy wire.

[0111] Comparative Example 2

[0112] The titanium alloy wire was processed according to the exact same steps and parameters as in Embodiment 2 of this application. The difference was that the proportional parameter of the PID controller at each position of the continuous annealing furnace was set to a fixed value of 15, and the integral and derivative parameters were set according to K. i,x =K p,x / T i K d,x =K p,x ×T dCalculations are performed to obtain the parameters of the PID controller, which controls the temperature at each location in the continuous annealing furnace at each time period, and finally processes the titanium alloy wire.

[0113] Comparative Example 3

[0114] The titanium alloy wire was processed according to the exact same steps and parameters as in Embodiment 3 of this application. The difference was that the proportional parameter of the PID controller at each position of the continuous annealing furnace was set to a fixed value of 15, and the integral and derivative parameters were set according to K. i,x =K p,x / T i K d,x =K p,x ×T d Calculations are performed to obtain the parameters of the PID controller, which controls the temperature at each location in the continuous annealing furnace at each time period, and finally processes the titanium alloy wire.

[0115] The performance of the titanium alloy wires processed according to the embodiments and comparative examples of this application was tested, and the results are shown in Table 1.

[0116] Table 1. Test results of titanium alloy wire properties

[0117]

[0118]

[0119] As shown in Table 1, this application improves the accuracy of temperature control during the annealing process by adjusting the proportional parameters of the PID controller, thereby improving the tensile properties of the titanium alloy wire.

[0120] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, the above description focuses on specific embodiments of this specification. Additionally, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some implementations, multitasking and parallel processing are possible or may be advantageous.

[0121] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0122] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them; modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some of the technical features, do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A processing method for tensile-strength titanium alloy wire, characterized in that, The process includes: Aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen, and titanium are placed in a vacuum arc furnace in a certain proportion for melting to obtain titanium alloy ingots; the chemically cleaned titanium alloy ingots are then heated and forged. The forged billet is rolled and drawn, and the drawn wire is annealed in a continuous annealing furnace. The temperature at each location in each temperature zone of the continuous annealing furnace is collected at each time. The temperature zones in the continuous annealing furnace are arranged in sequence as preheating zone, heating zone, soaking zone, and cooling zone. Analyze the temperature differences between each location and its neighboring locations at each time point to determine the heat loss rate at each location at each time point; based on the temperature difference between each location and the target temperature at each time point within each preset time period, and in conjunction with the heat loss rate, determine the heat diffusion fluctuation rate of each location within each time period. For the preheating zone and the heating zone, the heat flow coefficient of each location in the preheating zone and the heating zone in each time period is determined by the difference in heat diffusion fluctuation between each location and all locations to its left in each time period. For the heat spreader and cooling zone, the heat flow coefficient of each location in the heat spreader and cooling zone is determined by the difference in heat diffusion fluctuation between each location in each time period and a set location in the same temperature zone. Based on the heat flow coefficient of each location in each time period and the previous time period, and combined with the proportional parameters of the PID controller of each location in the previous time period, the proportional parameters of the PID controller of each location in each time period are determined, and the temperature of each location is controlled by the PID controller. After annealing, titanium alloy wire is obtained; The determination of the degree of heat loss includes: Obtain the location corresponding to the maximum temperature among all locations at each time point, and record it as the maximum location; For each moment, if any position is to the left of the maximum position, calculate the temperature difference between the left adjacent position and the position and the position, and record it as the first difference. Calculate the temperature difference between the position and the right adjacent position, and record it as the second difference. The heat loss of any position at each moment is the sum of the first difference and the second difference. Otherwise, calculate the temperature difference between the right adjacent position and the location of any given position, and record it as the third difference. Calculate the temperature difference between the location of any given position and its left adjacent position, and record it as the fourth difference. The heat loss of any given position at each time moment is the sum of the third difference and the fourth difference.

2. The tensile titanium alloy wire processing technology as described in claim 1, characterized in that, The proportions of aluminum, vanadium, iron, carbon, nitrogen, hydrogen, and oxygen are as follows: Aluminum is 5.5-6.8%, vanadium is 3.5-4.5%, iron is ≤0.30%, carbon is ≤0.08%, nitrogen is ≤0.05%, hydrogen is ≤0.015%, oxygen is ≤0.20%, and the balance is titanium raw material.

3. The tensile titanium alloy wire processing technology as described in claim 1, characterized in that, The maximum smelting current of the vacuum self-consuming electric arc furnace is 1500A, the operating voltage is 20~45V, and the operating vacuum degree is 1×10⁻⁶. -1 Pa~10 -2 Pa.

4. The tensile titanium alloy wire processing technology as described in claim 1, characterized in that, The chemical cleaning process involves first using a grinding wheel to remove oxide scale, inclusions, and surface defects from the surface of the titanium alloy ingot, and then chemically cleaning the titanium alloy ingot with hydrofluoric acid.

5. The tensile titanium alloy wire processing technology as described in claim 1, characterized in that, The heating forging temperature is 900℃~1200℃; the rolling temperature is 800℃~1100℃; the drawing is performed by drawing 10~15 times through a wire drawing machine to make the final wire diameter ≤0.5mm.

6. The tensile titanium alloy wire processing technology as described in claim 1, characterized in that, The temperature of the preheating zone is 400℃~500℃, the temperature of the heating zone is 750℃~900℃, the temperature of the heat spreader zone is 750℃~900℃, and the cooling zone is subjected to isothermal annealing, followed by air cooling after holding at 600℃~650℃.

7. The tensile titanium alloy wire processing technology as described in claim 1, characterized in that, The determination of the thermal diffusion fluctuation includes: For each location, the difference between the temperature and the target temperature at each time within each time period is calculated and recorded as the fifth difference. The absolute value of the sum of the fifth difference and the heat loss at each time at each location is calculated. The heat diffusion fluctuation is the average of the absolute values ​​at all times within each time period at each location.

8. The tensile titanium alloy wire processing technology as described in claim 1, characterized in that, The determination of the heat flow coefficient at each location in the preheating and heating zones over each time period includes: For each time period, if any position is located in the preheating zone or the heating zone, the difference between the thermal diffusion fluctuation of the position and each position to its left is calculated and recorded as the sixth difference. The sum of the sixth differences between the position and each position to its left is calculated, and the heat flow coefficient of the position in each time period is the normalized value of the sum. The determination of the heat flow coefficient of each location in the heat homogenization zone and the cooling zone in each time period includes: if any location is located in the heat homogenization zone, then calculate the difference in heat diffusion fluctuation between any location and each location in the heat homogenization zone, which is recorded as the seventh difference. The heat flow coefficient of any location in each time period is the normalized value of the sum of the seventh differences between any location and all locations in the heat homogenization zone. If any of the positions is located in the cooling zone, the difference between the thermal diffusion fluctuation of each position to the right of the position and that of the position is calculated and recorded as the eighth difference. The heat flow coefficient of the position in each time period is the normalized value of the sum of the eighth difference between the position to the right of the position and that of the position.

9. The tensile titanium alloy wire processing technology as described in claim 1, characterized in that, The expression for determining the proportional parameters of the PID controller at each location and time period is as follows: In the formula, Let x be the proportional parameter of the PID controller at each time period. Let x be the proportional parameter of the PID controller in the previous time period for each position. Let x be the heat flow coefficient at the x-th location in each time period. Let x be the heat flow coefficient of the x-th position in the previous time period.

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