Tensile titanium alloy wire processing technology

Abstract

The invention relates to the technical field of titanium material manufacturing, in particular to a tensile titanium alloy wire machining process which comprises the steps that aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen and titanium are put into a vacuum consumable electric arc furnace in proportion to be smelted, and a titanium alloy cast ingot is obtained; the titanium alloy cast ingot obtained after chemical cleaning is heated and forged; the forged blank is rolled and drawn, and the drawn wire is subjected to annealing treatment; collecting the temperature of each position of each temperature area in the continuous annealing furnace at each moment, and determining the thermal diffusion fluctuation of each position in the continuous annealing furnace in each time period; calculating the heat flow coefficient of each position in the continuous annealing furnace in each time period; acquiring proportional parameters of a PID controller in each position and each time period in the continuous annealing furnace, and controlling the temperature of each position by using the PID controller; and the titanium alloy wire is obtained after annealing treatment. The tensile property of the titanium alloy wire is improved.

Description

Technical Field

[0001] The present application relates to the technical field of titanium material manufacturing, and in particular to a process for processing tensile-resistant titanium alloy wire. Background Art

[0002] Titanium alloy wire is a crucial base material in titanium manufacturing and is widely used in aerospace, medical, and other fields. It can be processed into a variety of precise shapes and sizes to meet the specific material form and performance requirements of various fields. Especially in high-precision industries such as aerospace, titanium alloy wire processing can provide the required precise dimensions and stable performance.

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

[0004] In order to solve the above technical problems, the present application provides a tensile titanium alloy wire processing process to solve the existing problems.

[0005] A tensile titanium alloy wire processing process of the present application adopts the following technical solution:

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

[0007] Aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen and titanium are placed in a vacuum consumable arc furnace in proportion for smelting to obtain a titanium alloy ingot; the titanium alloy ingot after chemical cleaning is heated and forged;

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

[0009] Collecting the temperature of each position in each temperature zone of the continuous annealing furnace at each time, wherein the temperature zones in the continuous annealing furnace are sequentially arranged as a preheating zone, a heating zone, a soaking zone, and a cooling zone;

[0010] Analyze the temperature difference between each location and its adjacent locations at each moment to determine the heat loss degree at each location at each moment; determine the thermal diffusion fluctuation degree of each location in each time period based on the difference between the temperature at each location at each moment in each preset time period and the target temperature, combined with the heat loss degree;

[0011] For the preheating area and heating area, the heat flow coefficient of each position in each time period is determined by the difference in heat diffusion fluctuation between each position and all positions to its left in each time period;

[0012] For the soaking zone and cooling zone, the heat flow coefficient of each position in each time period is determined by the difference in thermal diffusion fluctuation between each position in each time period and the set position in the same temperature zone;

[0013] Based on the heat flow coefficient of each position in each time period and the previous time period, combined with the proportional parameter of the PID controller of each position in the previous time period, the proportional parameter of the PID controller of each position in each time period is determined, and the temperature of each position is controlled by the PID controller;

[0014] After annealing, titanium alloy wire is obtained.

[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 ≤0.30%, carbon ≤0.08%, nitrogen ≤0.05%, hydrogen ≤0.015%, oxygen ≤0.20%, and the balance is titanium raw material.

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

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

[0019] In one embodiment, the heating casting temperature is 900°C to 1200°C; the rolling temperature is 800°C to 1100°C; and the drawing is performed by a wire drawing machine for 10 to 15 passes to make the final wire diameter ≤0.5 mm.

[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 soaking zone is 750℃~900℃, and the cooling zone adopts isothermal annealing, and is air-cooled after keeping warm at 600℃~650℃.

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

[0022] Get the position corresponding to the maximum temperature among all positions at each moment and record it as the maximum position;

[0023] At each moment, if any position is to the left of the maximum position, the temperature difference between the position adjacent to the left of the position and the position is calculated, recorded as the first difference, and the temperature difference between the position and the position adjacent to the right of the position is calculated, recorded as the second difference. The heat loss degree of the position at each moment is the sum of the first difference and the second difference.

[0024] Otherwise, calculate the temperature difference between the adjacent position on the right side of any position and the said arbitrary position, record it as the third difference, calculate the temperature difference between any position and the adjacent position on the left side of any position, record it as the fourth difference, and the heat loss degree of any position at each 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 position, the difference between the temperature at each moment in each time period and the target temperature is calculated, recorded as the fifth difference, and the absolute value of the sum of the fifth difference and the heat loss degree at each position at each moment is calculated. The thermal diffusion fluctuation degree is the average of the absolute values ​​at all moments in each time period for each position.

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

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

[0029] Determining the heat flow coefficient of each position in the soaking area and the cooling area in each time period includes: if any position is located in the soaking area, calculating the difference in thermal diffusion fluctuation between the any position and each position in the soaking area, recording it as a seventh difference, and the heat flow coefficient of any position in each time period is a normalized value of the sum of the seventh differences between the any position and all positions in the soaking area;

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

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

[0032] Where K p,x K is the proportional parameter of the PID controller at the xth position in each time period, p,x ′ is the proportional parameter of the PID controller of the x-th position in the previous time period of each time period, sr x is the heat flow coefficient at the x-th position in each time period, sr x ′ is the heat flow coefficient of the x-th position in the previous time period of each time period.

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

[0034] The present application calculates the thermal diffusion fluctuation of each position in the continuous annealing furnace in each time period, and can accurately quantify the temperature fluctuation of each position in the continuous annealing furnace at different times, which helps to clearly understand the temperature stability of each area, so as to more accurately regulate the temperature of the annealing furnace; further, the heat flow coefficient of each position in the continuous annealing furnace in each time period is determined, which reflects the heat flow from the high-temperature area to the low-temperature area in the continuous annealing furnace, and embodies the temperature stability of each position in the continuous annealing furnace in each time period, thereby improving the accuracy and reliability of subsequent temperature control; the heat flow coefficient is used to determine the proportional parameters of the PID controller of each position and each time period, and the PID controller is used to control the temperature of each position, thereby achieving annealing. The adaptive adjustment of the temperature field in the furnace helps the PID controller to quickly respond to temperature deviations and improve annealing uniformity. Compared with traditional fixed-parameter PID control, the present application can dynamically adjust the control strategy according to actual temperature fluctuations to avoid unsatisfactory annealing effects due to temperature fluctuations, thereby significantly improving the accuracy of temperature control. Stable temperature control is conducive to the uniform generation and distribution of primary α phase and secondary α phase of titanium alloy wire. The content and distribution of primary α phase and secondary α phase play a key role in the tensile strength and other performance indicators of titanium alloy wire. By optimizing the crystallization process, the microstructure of the titanium alloy wire is made more uniform, thereby effectively improving the tensile strength of the titanium alloy wire, reducing performance fluctuations caused by temperature fluctuations, and improving the quality of the finished product of titanium alloy wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

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

[0037] Figure 2 This is a schematic diagram of 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 DESCRIPTION

[0039] To further illustrate the technical means and effectiveness of this application's implementation of the intended invention, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effectiveness of a tensile-resistant titanium alloy wire processing process proposed in this application. In the following description, references to different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0040] Unless defined otherwise, 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 belongs.

[0041] The specific solution of a tensile-type titanium alloy wire processing technology provided by the present application is described in detail below with reference to the accompanying drawings.

[0042] Example 1

[0043] See also Figure 1 , which shows a flowchart of the steps of a tensile titanium alloy wire processing process provided in Example 1 of the present application, the process comprising:

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

[0045] Aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen, and titanium are placed in a vacuum consumable arc furnace in proportion for smelting. 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%. In this embodiment, 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%. The remainder is titanium (Ti) raw material. According to the above proportions, the materials are placed in a vacuum consumable arc furnace. The maximum smelting current of the vacuum consumable arc furnace is 1500A; the operating voltage is 20-45V, and the ultimate vacuum degree is 1.33×10-2 Pa, working vacuum degree: 1×10 -1 Pa~10 -2 Pa, all raw materials are arc-melted in a high vacuum environment, the electrodes are melted and solidified into ingots, and the preparation of titanium alloy ingots in titanium material manufacturing is realized.

[0046] S2: The titanium alloy ingot after chemical cleaning is heated and forged.

[0047] The titanium alloy ingots melted in S1 are cooled naturally. After cooling, the surface oxide scale, inclusions, and surface defects on the surface of the titanium alloy ingots are first removed using a grinding wheel. Then, the titanium alloy ingots are chemically cleaned using hydrofluoric acid.

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

[0049] S3: The forged billet is rolled and drawn.

[0050] The forged billet is heated to the rolling temperature of 800℃ and maintained for 5 minutes to ensure uniform temperature. The billet is rolled into coil billet through a rolling mill.

[0051] After rolling, the wire blank is pickled to remove surface oxide layers and defects. The surface of the wire blank is then pre-oxidized to form a protective film. The wire blank is then drawn through a wire drawing machine in 10 passes, gradually reducing its diameter to ≤0.5mm.

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

[0053] The drawn wire is annealed, specifically using a continuous annealing furnace. The continuous annealing furnace includes four temperature zones: preheating zone, heating zone, soaking zone, and cooling zone. The temperature range of the preheating zone during annealing is 400°C to 500°C, the temperature range of the heating zone is 750°C to 900°C, and the temperature range of the soaking zone is 750°C to 900°C. After complete annealing, it is slowly cooled. The cooling zone adopts isothermal annealing, and the isothermal annealing is carried out at 600°C to 650°C and then air-cooled. This application controls the temperature of each temperature zone during the annealing process, specifically:

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

[0055] For each temperature zone in the continuous annealing furnace, namely the preheating zone, heating zone, soaking zone, and cooling zone, this embodiment evenly distributes 4 temperature sensors in each temperature zone, and each temperature sensor corresponds to a position in the temperature zone to which it belongs, so that a total of 16 temperature sensors are installed in the continuous annealing furnace. Since the arrangement order of the temperature zones in the continuous annealing furnace is preheating zone, heating zone, soaking zone, and cooling zone, the serial number of the corresponding position of each temperature sensor can be obtained according to the arrangement order of the temperature sensors from left to right. The schematic diagram of the distribution of temperature zones and temperature sensors in the continuous annealing furnace is shown in FIG. Figure 2 shown.

[0056] Then, a temperature sensor is used to collect the temperature of each position in each temperature zone of the continuous annealing furnace during annealing of the titanium alloy wire. The collection frequency is 100 Hz and the collection period is 2 seconds. The implementer can set it according to the actual situation, and this embodiment does not impose any restrictions on this. One collection period is regarded as a time period. The temperature collected by each temperature sensor is denoised by mean filtering, and the temperature data of all moments in each time period at each position after denoising are arranged in the order of collection time to obtain the annealing temperature sequence of each position and time period. Among them, mean filtering is an existing well-known technology, and the specific process will not be repeated here. The implementer can choose other existing feasible filtering algorithms on his own, and this embodiment does not impose any restrictions on this.

[0057] S402: Analyze the temperature difference between each position and its adjacent positions at each moment to determine the heat loss degree of each position at each moment; based on the difference between the temperature of each position at each moment in each preset time period and the target temperature, combined with the heat loss degree, determine the thermal diffusion fluctuation degree of each position in each time period.

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

[0059] It should be noted that, if there are multiple maximum values ​​in the temperatures of all positions at each moment, the average of the position numbers corresponding to the multiple maximum values ​​is recorded as the maximum position G.

[0060] Therefore, in order to analyze the thermal diffusivity of the temperature at different positions in the continuous annealing furnace, this embodiment determines the heat loss degree at each position at each moment based on the temperature difference between each position and its adjacent positions at each moment. The specific calculation method is:

[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] Where, Cl j , Cl i They represent the heat loss at the jth and ith positions in the continuous annealing furnace at each moment, T j+1 、T j 、T j-1 are the temperatures of the j+1th, jth, and j-1th positions in the continuous annealing furnace at each moment, T i-1 、T i 、T i+1 are the temperatures of the i-1th, i-th, and i+1th positions in the continuous annealing furnace at each moment. j-1 -T j ) is recorded as the first difference, for the j-th position, the j-1-th position is the left adjacent position of the j-th position; (T j -T j+1 ) is recorded as the second difference, for the jth position, the j+1th position is the right adjacent position of the jth position; (T i+1 -T i ) is recorded as the third difference, for the i-th position, the i+1-th position is the right adjacent position of the i-th position; (T i -T i-1 ) is recorded as 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 by difference, ratio, absolute value of difference, etc., and is not limited in this embodiment.

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

[0066] In the process of annealing titanium alloy wire, it is necessary to maintain the temperature stability of each stage. This is because unstable temperature will affect the content and distribution of primary α phase and secondary α phase in titanium alloy, thereby reducing the tensile strength of titanium alloy wire. At the same time, unstable temperature may also cause fluctuations in performance indicators such as hardness and cross-sectional shrinkage of titanium alloy wire, causing quality problems of titanium alloy wire. Due to the existence of thermal diffusion, the temperature of different temperature zones in the continuous annealing furnace changes when annealing titanium alloy wire. When thermal diffusion fluctuates, it means that the temperature of each temperature zone in the continuous annealing furnace cannot be balanced, and the greater the thermal diffusion fluctuation, the more unbalanced the tensile strength of each part of the produced titanium alloy wire, resulting in a decrease in the tensile strength of the titanium alloy wire.

[0067] Therefore, this embodiment first sets the target temperature of each position in each temperature zone of the continuous annealing furnace, wherein, for the soaking zone, the target temperature of all positions is set to 500°C, for the heating zone and the soaking zone, the target temperature of all positions is set to 840°C, and 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 actual conditions, and this embodiment does not impose any restrictions on this.

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

[0069] Where PF x It represents the thermal diffusion fluctuation of the xth position in the continuous annealing furnace in each time period, ht x,y is the temperature of the xth position in the continuous annealing furnace at the yth moment in each time period, H x is the target temperature of the xth position in the continuous annealing furnace, CL x,y is the heat loss degree of the xth position in the continuous annealing furnace at the yth moment in each time period, and m is the number of moments in each time period. x,y -Hx Recorded as the fifth difference.

[0070] It should be understood that, ideally, the annealing temperature of a continuous annealing furnace should be the same for titanium alloy wire at different times at the same location. The greater the variation in heat loss, the less stable the continuous annealing furnace's temperature. Drastic temperature fluctuations can disrupt the titanium alloy's phase transformation and crystallization during annealing, reducing the amount of primary and secondary α-phase crystals in the titanium alloy wire and leading to an uneven microstructure. This reduction in primary and secondary α-phase directly impacts the titanium alloy wire's tensile strength, reducing it.

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

[0072] Different temperature zones of the continuous annealing furnace have different effects on the titanium alloy wire. The function of the preheating zone and the heating zone is to heat the titanium alloy wire. Due to the continuous movement of the titanium alloy, the heating time of different zones of the titanium alloy wire is different. Therefore, the temperature required by the titanium alloy wire is also different. The closer the titanium alloy wire is to the soaking zone, the higher the temperature is, and the less heat it needs to absorb. The soaking zone has the highest heat, and the heat in the soaking zone will flow to other temperature zones. In order to evaluate the heat flow phenomenon in different temperature zones, this embodiment calculates the heat flow coefficient of each position in the continuous annealing furnace in each time period based on the difference in thermal diffusion fluctuation between each position and its adjacent positions in each time period. The specific calculation method is:

[0073]

[0074]

[0075]

[0076] Where sr x It represents the heat flow coefficient of the xth position in the continuous annealing furnace in each time period, PF x Indicates the thermal diffusion fluctuation of the xth position in the continuous annealing furnace in each time period, PF kIt represents the thermal diffusion fluctuation degree at the k-th position in the continuous annealing furnace during 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. Take (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 absorbed heat 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, during each time period, if the difference between the thermal diffusion fluctuation degree of the x-th position and that of all the 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 the 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 the 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 it is necessary to enhance temperature control to better produce titanium alloy wires with higher tensile strength.

[0078] S404: Based on the heat flow coefficients of each position during 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 for each position during 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 wires is continuously decreasing, that is, the greater the heat flow coefficient at each position in the continuous annealing furnace in each time period, the greater the PID controller in the annealing furnace is. This indicates that the PID controller in the annealing furnace is unable to effectively control the temperature in the annealing furnace. In the process of decreasing temperature stability, it is necessary to increase the various parameters of the PID controller to ensure that the processing of titanium alloy wires can run smoothly. Therefore, this embodiment determines the proportional parameters of the PID controller at each position and each time period in the continuous annealing furnace, and the expression is:

[0080] Where K p,x K is the proportional parameter of the PID controller at the xth position in each time period, p,x ′ is the proportional parameter of the PID controller of the x-th position in the previous time period of each time period, sr x is the heat flow coefficient at the x-th position in each time period, sr x ′ is the heat flow coefficient of the x-th position in the previous time period of each time period.

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

[0082] The calculation of the integral parameter and differential parameter of the PID controller are:

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

[0084] Therefore, the PID controller at each position of the continuous annealing furnace uses the calculated proportional parameters, integral parameters, and differential parameters to control and adjust the error between the actual temperature and the target temperature in the continuous annealing furnace, so that the temperature in the continuous annealing furnace is maintained at the target temperature. The flow chart for determining the proportional parameters of the PID controller is as follows: Figure 3 shown.

[0085] S5: After annealing, the titanium alloy wire is obtained.

[0086] After annealing, the titanium alloy wire is obtained. High-precision measuring equipment is used to test the diameter, ovality, and other dimensional parameters of the titanium alloy wire to ensure that they meet standard requirements. In this embodiment, the high-precision measuring equipment is a micrometer. The implementer can choose other existing high-precision measuring equipment, such as a caliper.

[0087] Example 2

[0088] See also Figure 1 , which shows a flowchart of the steps of a tensile titanium alloy wire processing process provided in Example 2 of the present application, the process comprising:

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

[0090] Aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen, and titanium are placed in a vacuum consumable arc furnace in proportion for smelting. 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%. In this embodiment, 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%. The remainder is titanium (Ti) raw material. According to the above proportions, the materials are placed in a vacuum consumable arc furnace. The maximum smelting current of the vacuum consumable arc furnace is 1500A; the operating voltage is 20-45V, and the ultimate vacuum degree is 1.33×10 -2 Pa, working vacuum degree: 1×10 -1 Pa~10 -2 Pa, all raw materials are arc-melted in a high vacuum environment, the electrodes are melted and solidified into ingots, and the preparation of titanium alloy ingots in titanium material manufacturing is realized.

[0091] S2: The titanium alloy ingot after chemical cleaning is heated and forged.

[0092] The titanium alloy ingots melted in S1 are cooled naturally. After cooling, the ingots are first sandblasted to remove the oxide scale, inclusions, and surface defects on the surface. Then, the ingots are chemically cleaned with nitric acid.

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

[0094] S3: The forged billet is rolled and drawn.

[0095] The forged billet is heated to the rolling temperature of 1000℃ and maintained for 8 minutes to ensure uniform temperature. The billet is rolled into coil billet through a rolling mill.

[0096] After rolling, the wire blanks are pickled to remove surface oxide layers and defects. The surface of the wire blanks is then pre-oxidized to form a protective film. The wire blanks are then drawn through a wire drawing machine in 13 passes, gradually reducing their diameter to ≤0.5mm.

[0097] The remaining steps are processed in exactly the same manner as in Example 1 of the present application to obtain a titanium alloy wire.

[0098] Example 3

[0099] See also Figure 1 , which shows a flowchart of the steps of a tensile titanium alloy wire processing process provided in Example 3 of the present application, the process comprising:

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

[0101] Aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen, and titanium are placed in a vacuum consumable arc furnace in proportion for smelting. 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%. In this embodiment, 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%. The remainder is titanium (Ti) raw material. According to the above proportions, the materials are placed in a vacuum consumable arc furnace. The maximum smelting current of the vacuum consumable arc furnace is 1500A; the operating voltage is 20-45V, and the ultimate vacuum degree is 1.33×10 -2 Pa, working vacuum degree: 1×10 -1 Pa~10 -2 Pa, all raw materials are arc-melted in a high vacuum environment, the electrodes are melted and solidified into ingots, and the preparation of titanium alloy ingots in titanium material manufacturing is realized.

[0102] S2: The titanium alloy ingot after chemical cleaning is heated and forged.

[0103] The titanium alloy ingots melted in S1 are cooled naturally. After cooling, the surface oxide scale, inclusions, and surface defects on the surface of the titanium alloy ingots are first removed using a grinding wheel. Then, the titanium alloy ingots are chemically cleaned using hydrofluoric acid.

[0104] The titanium alloy ingot after chemical cleaning is heated to 1200°C by electric heating, and then forged by a press into a titanium rod with a diameter of 15 mm.

[0105] S3: The forged billet is rolled and drawn.

[0106] The forged billet is heated to the rolling temperature of 1100°C and maintained at this temperature for 10 minutes to ensure uniform temperature. The billet is then rolled into a coil billet through a rolling mill.

[0107] After rolling, the wire blank is pickled to remove surface oxide layers and defects. The surface of the wire blank is then pre-oxidized to form a protective film. The wire blank is then drawn through a wire drawing machine in 15 passes, gradually reducing its diameter to ≤0.5mm.

[0108] The remaining steps are processed in exactly the same manner as in Example 1 of the present application to obtain a titanium alloy wire.

[0109] Comparative Example 1

[0110] The titanium alloy wire was processed according to the same steps and parameters as in Example 1 of the present 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 parameter and the differential parameter 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 various parameters of the PID controller, and the temperature of each position in the continuous annealing furnace is controlled in each time period to finally obtain titanium alloy wire.

[0111] Comparative Example 2

[0112] The titanium alloy wire was processed according to the same steps and parameters as in Example 2 of the present 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 parameter and the differential parameter 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 various parameters of the PID controller, and the temperature of each position in the continuous annealing furnace is controlled in each time period to finally obtain titanium alloy wire.

[0113] Comparative Example 3

[0114] The titanium alloy wire was processed according to the same steps and parameters as in Example 3 of the present 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 parameter and the differential parameter 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 various parameters of the PID controller, and the temperature of each position in the continuous annealing furnace is controlled in each time period to finally obtain titanium alloy wire.

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

[0116] Table 1 Titanium alloy wire performance test results

[0117]

[0118]

[0119] As can be seen from Table 1, the present 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 in which the embodiments of the present application are presented is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. Furthermore, the foregoing descriptions of specific embodiments of this specification are provided. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order or sequential sequence shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

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

[0122] The above-described embodiments are only used to illustrate the technical solutions of the present application, and not to limit them. Modifications to the technical solutions described in the aforementioned embodiments, or equivalent replacements of some of the technical features therein, do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A tensile titanium alloy wire processing process, characterized in that: The process includes: Aluminum, vanadium, iron, carbon, nitrogen, hydrogen, oxygen and titanium are placed in a vacuum consumable arc furnace in proportion for smelting to obtain a titanium alloy ingot; the titanium alloy ingot after chemical cleaning is heated and forged; The forged billet is rolled and drawn, and the drawn wire is annealed in a continuous annealing furnace; Collecting the temperature of each position in each temperature zone of the continuous annealing furnace at each time, wherein the temperature zones in the continuous annealing furnace are sequentially arranged as a preheating zone, a heating zone, a soaking zone, and a cooling zone; Analyze the temperature difference between each location and its adjacent locations at each moment to determine the heat loss degree at each location at each moment; determine the thermal diffusion fluctuation degree of each location in each time period based on the difference between the temperature at each location at each moment in each preset time period and the target temperature, combined with the heat loss degree; For the preheating area and heating area, the heat flow coefficient of each position in each time period is determined by the difference in heat diffusion fluctuation between each position and all positions to its left in each time period; For the soaking zone and cooling zone, the heat flow coefficient of each position in each time period is determined by the difference in thermal diffusion fluctuation between each position in each time period and the set position in the same temperature zone; Based on the heat flow coefficient of each position in each time period and the previous time period, combined with the proportional parameter of the PID controller of each position in the previous time period, the proportional parameter of the PID controller of each position in each time period is determined, and the temperature of each position is controlled by the PID controller; After annealing, titanium alloy wire is obtained.

2. A tensile titanium alloy wire processing process according to claim 1, characterized in that: The ratio of aluminum, vanadium, iron, carbon, nitrogen, hydrogen and oxygen is: Aluminum is 5.5-6.8%, vanadium is 3.5-4.5%, iron ≤0.30%, carbon ≤0.08%, nitrogen ≤0.05%, hydrogen ≤0.015%, oxygen ≤0.20%, and the balance is titanium raw material.

3. A tensile titanium alloy wire processing process according to claim 1, characterized in that: The maximum melting current of the vacuum consumable arc furnace is 1500A, the working voltage is 20-45V, and the working vacuum degree is 1×10 -1 Pa~10 -2 Pa.

4. A tensile titanium alloy wire processing process according to claim 1, characterized in that: The chemical cleaning is to first use a grinding wheel to remove the oxide scale, inclusions and surface defects on the surface of the titanium alloy ingot, and then chemically clean the titanium alloy ingot with hydrofluoric acid.

5. The process for processing a tensile-resistant titanium alloy wire according to claim 1, wherein: The heating casting temperature is 900° C. to 1200° C.; the rolling temperature is 800° C. to 1100° C.; and the drawing is performed by a wire drawing machine for 10 to 15 passes to make the final wire diameter ≤0.5 mm.

6. A tensile titanium alloy wire processing process according to claim 1, characterized in that: The temperature of the preheating zone is 400°C to 500°C, the temperature of the heating zone is 750°C to 900°C, the temperature of the soaking zone is 750°C to 900°C, and the cooling zone adopts isothermal annealing, keeping warm at 600°C to 650°C and then air cooling.

7. A process for processing a tensile-resistant titanium alloy wire according to claim 1, characterized in that: The determination of the heat loss degree includes: Get the position corresponding to the maximum temperature among all positions at each moment and record it as the maximum position; At each moment, if any position is to the left of the maximum position, the temperature difference between the position adjacent to the left of the position and the position is calculated, recorded as the first difference, and the temperature difference between the position and the position adjacent to the right of the position is calculated, recorded as the second difference. The heat loss degree of the position at each moment is the sum of the first difference and the second difference. Otherwise, calculate the temperature difference between the adjacent position on the right side of any position and the said arbitrary position, record it as the third difference, calculate the temperature difference between any position and the adjacent position on the left side of any position, record it as the fourth difference, and the heat loss degree of any position at each moment is the sum of the third difference and the fourth difference.

8. The process for processing a tensile-resistant titanium alloy wire according to claim 1, wherein: The determination of the thermal diffusion fluctuation degree includes: For each position, the difference between the temperature at each moment in each time period and the target temperature is calculated, recorded as the fifth difference, and the absolute value of the sum of the fifth difference and the heat loss degree at each position at each moment is calculated. The thermal diffusion fluctuation degree is the average of the absolute values ​​at all moments in each time period for each position.

9. A process for processing a tensile-resistant titanium alloy wire according to claim 1, characterized in that: Determining the heat flow coefficient at each position in the preheating area and the heating area in each time period includes: For each time period, if any position is located in the preheating area or the heating area, the difference in thermal diffusion fluctuation between the position and each position to its left is calculated, recorded as the sixth difference, and the cumulative sum of the sixth differences between the position and all positions to its left is calculated. The heat flow coefficient of the position in each time period is the normalized value of the cumulative sum; Determining the heat flow coefficient of each position in the soaking area and the cooling area in each time period includes: if any position is located in the soaking area, calculating the difference in thermal diffusion fluctuation between the any position and each position in the soaking area, recording it as a seventh difference, and the heat flow coefficient of any position in each time period is a normalized value of the sum of the seventh differences between the any position and all positions in the soaking area; If any of the positions is located in the cooling area, the difference in thermal diffusion fluctuation between the positions to the right of the any of the positions and the any of the positions is calculated and recorded as the eighth difference. The heat flow coefficient of the any of the positions in each time period is the normalized value of the sum of the eighth difference between all the positions to the right of the any of the positions and the any of the positions.

10. The process for processing a tensile-resistant titanium alloy wire according to claim 1, wherein: The proportional parameters of the PID controller at each position and time period are determined as follows: Where K p,x K is the proportional parameter of the PID controller at the xth position in each time period, p,x ′ is the proportional parameter of the PID controller of the x-th position in the previous time period of each time period, sr x is the heat flow coefficient at the x-th position in each time period, sr x ′ is the heat flow coefficient of the x-th position in the previous time period of each time period.

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