Titanium alloy ingot preparation method with coordinated control of melting rate and cooling rate

Abstract

This invention discloses a method for preparing titanium alloy ingots with coordinated control of melting rate and cooling rate, specifically implemented according to the following steps: S1, establishing a finite element model of vacuum self-consuming arc melting of titanium alloy ingots, completing mesh generation, and setting core process and physical property parameters; S2, determining parameter gradient values ​​and calculating deviation; S3, dividing the melting process into three stages: arc initiation period, normal melting period, and feeding period, ensuring that the average elemental composition deviation throughout the process is within the range of 0.02~0.06; S4, evaluating and analyzing the composition at the head, middle, and tail points and the longitudinal section composition of the ingot after melting. This method solves the ingot quality problem caused by mismatched process parameters in existing VAR melting processes, improves ingot quality and performance, and reduces production costs.

Description

Technical Field

[0001] This invention belongs to the field of special metal metallurgy technology, specifically relating to a method for preparing titanium alloy ingots with coordinated control of melting rate and cooling rate. Background Technology

[0002] Titanium alloys are widely used in high-end fields such as aerospace due to their high strength, low density, and excellent corrosion resistance. Vacuum arc remelting (VAR) is the mainstream process for preparing titanium alloy ingots, but existing VAR processes have significant technical bottlenecks: during the melting process, the melting rate and cooling rate are independently controlled, lacking an effective matching mechanism. This leads to unstable temperature gradients in the molten pool, changes in the solidification front morphology, and a series of metallurgical defects. Specifically, for large-sized ingots, if the melting rate is too high and the cooling is insufficient during the stabilization stage, it will result in an excessively deep molten pool and severe element segregation; if the melting rate is too low and the cooling is too fast, it will easily cause uneven advancement of the solidification front interface, leading to solute depletion at the ingot edge, and also significantly increasing production costs and cycle time.

[0003] Therefore, there is an urgent need to develop a method for preparing titanium alloy ingots with coordinated control of melting rate and cooling rate to overcome the technical defects in the existing VAR melting process and meet the growing demand for high-quality metal materials. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing titanium alloy ingots with coordinated control of melting rate and cooling rate, which solves the ingot quality problem caused by mismatch of process parameters in the existing VAR melting process, improves ingot quality and performance, and reduces production costs.

[0005] The technical solution adopted in this invention is a method for preparing titanium alloy ingots by synergistic control of melting rate and cooling rate, specifically implemented according to the following steps:

[0006] S1. Establish a finite element model for vacuum self-consuming electric arc melting of titanium alloy ingots, complete mesh generation, and set core process and physical property parameters.

[0007] S2. Determination of parameter gradient values ​​and calculation of deviation;

[0008] S3. Divide the smelting process into three stages: arc initiation period, normal smelting period, and feeding period, to ensure the deviation of the average elemental composition throughout the process. It is within the range of 0.02 to 0.06;

[0009] S4. Evaluate and analyze the composition of the head, middle and tail longitudinal points and the longitudinal section composition of the ingot after melting.

[0010] The invention is further characterized in that:

[0011] In step S1, the specifications of the finite element model for vacuum consumable arc melting of titanium alloy ingots are as follows: 520mm~ 920mm.

[0012] In step S1, the established finite element model of vacuum consumable arc melting of titanium alloy ingots is a two-dimensional axisymmetric structure.

[0013] In step S1, the core process and physical property parameters set specifically include: solid-liquid phase temperature, specific heat, thermal conductivity and dynamic viscosity in the range of 0~2200℃ as a function of temperature, radiation and convection heat transfer coefficients on the side of the ingot, and effective distribution coefficients of each element.

[0014] In step S2, the specific rules for the parameter gradient values ​​are as follows: when the melting rate is in the range of 6 kg / min to 23 kg / min, it is divided into a gradient of 2 kg / min; when the cooling rate is in the range of 0.1 K / s to 0.67 K / s, it is divided into a gradient of 0.09 K / s, forming a combination of multiple melting rate and cooling rate combinations that fully cover the range.

[0015] In step S2, the specific process for calculating the deviation is as follows: Based on the finite element model of vacuum self-consuming arc melting of titanium alloy ingots established in S1, the parameter combinations are divided according to the specific rules for parameter gradient values, and the deviation of the average elemental composition under each parameter combination is calculated. The calculation formula is as follows:

[0016] ;

[0017] In the formula, This represents the element mass fraction at each grid node along the axial positions of the ingot edge, R / 2, and center. This represents the average mass fraction of elements in the entire ingot.

[0018] In step S3, a combination of a high melting rate of 7.5 kg / min to 23.0 kg / min and a medium-low cooling rate of 0.15 K / s to 0.25 K / s is used during the arc initiation period to ensure stable formation of the molten pool;

[0019] In step S3, during the normal smelting period, a combination of a medium-high melting rate of 6.0 kg / min to 21.0 kg / min and a medium cooling rate of 0.38 K / s to 0.50 K / s is used to balance efficiency and composition uniformity.

[0020] In step S3, during the feeding period, the melting rate is gradually reduced to 0 kg / min and the cooling rate is 0.13 K / s to 0.40 K / s to optimize the consistency of composition.

[0021] The beneficial effects of this invention are:

[0022] (1) The method of the present invention effectively reduces the tendency of element segregation and reduces the size of shrinkage cavities by precisely controlling the matching of melting rate and cooling rate, thereby significantly improving the quality and performance of ingots and meeting the strict requirements of high-end fields for metal materials;

[0023] (2) The method of the present invention adopts an optimized strategy of matching melting rate and cooling rate, which improves the yield of ingots and reduces energy consumption and production costs;

[0024] (3) The method of the present invention determines the matching relationship by establishing a numerical model, which can be flexibly adjusted and optimized for different metal materials and ingot specifications, and has wide applicability and good application prospects. Attached Figure Description

[0025] Figure 1 This is a schematic diagram showing the melting rate and cooling rate at different stages of the entire smelting process in the method of the present invention;

[0026] Figure 2 This is a schematic diagram of longitudinal point sampling at the head of the ingot in an embodiment of the present invention;

[0027] Figure 3 Prepared as described in Example 1 of this invention Fe element content diagram in the longitudinal direction of the 520mm TB6 titanium alloy head;

[0028] Figure 4 Prepared as described in Example 2 of this invention Mo content diagram in the longitudinal direction of a 920mm Ti80 titanium alloy head;

[0029] Figure 5 Prepared for Comparative Example 1 of the present invention A graph showing the longitudinal Fe content of a 920mm TC4 titanium alloy head. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0031] This invention provides a method for preparing titanium alloy ingots with coordinated control of melting rate and cooling rate, specifically implemented according to the following steps:

[0032] S1. Establish a finite element model for vacuum self-consuming electric arc melting of titanium alloy ingots, complete mesh generation, and set core process and physical property parameters.

[0033] In step S1, the specifications of the finite element model for vacuum consumable arc melting of titanium alloy ingots are as follows: 520mm~ 920mm;

[0034] The established finite element model for vacuum self-consuming arc melting of titanium alloy ingots is a two-dimensional axisymmetric structure.

[0035] The core process and physical property parameters set specifically include: solid-liquid phase temperature, specific heat, thermal conductivity and dynamic viscosity in the range of 0~2200℃ as a function of temperature, radiation and convection heat transfer coefficients on the side of the ingot, and effective distribution coefficients of each element.

[0036] S2. Determination of parameter gradient values ​​and calculation of deviation;

[0037] In step S2, the specific rules for the parameter gradient values ​​are as follows: when the melting rate is in the range of 6 kg / min to 23 kg / min, it is divided into a gradient of 2 kg / min; when the cooling rate is in the range of 0.1 K / s to 0.67 K / s, it is divided into a gradient of 0.09 K / s, forming a combination of multiple melting rate and cooling rate combinations that fully cover the range.

[0038] The specific process for calculating the deviation is as follows: Based on the finite element model of vacuum self-consuming arc melting of titanium alloy ingots established by S1, the parameter combinations are divided according to the specific rules for parameter gradient values, and the deviation of the average elemental composition under each parameter combination is calculated. The calculation formula is as follows:

[0039] ;

[0040] In the formula, This represents the element mass fraction at each grid node along the axial positions of the ingot edge, R / 2, and center. This represents the average mass fraction of elements in the entire ingot.

[0041] S3, such as Figure 1 As shown, the smelting process is divided into three stages: the arc initiation period, the normal smelting period, and the feeding period. Targeted optimal process parameter combinations are used in each stage to ensure the deviation of the average elemental composition throughout the entire process. The value is within the range of 0.02 to 0.06 (based on production experience). Specifically, during the arc initiation period, a high melting rate of 7.5 kg / min to 23.0 kg / min and a medium-low cooling rate of 0.15 K / s to 0.25 K / s are used to ensure stable formation of the molten pool; during the normal melting period, a medium-high melting rate of 6.0 kg / min to 21.0 kg / min and a medium cooling rate of 0.38 K / s to 0.50 K / s are used to balance efficiency and compositional uniformity; during the feeding period, the melting rate is gradually reduced to 0 kg / min and the cooling rate is 0.13 K / s to 0.40 K / s to optimize compositional consistency.

[0042] S4. Evaluate and analyze the composition of the head, middle and tail longitudinal points and the longitudinal section composition of the ingot after melting.

[0043] The present invention will be further described in detail below with reference to specific embodiments.

[0044] Example 1

[0045] Preparation by coordinated control of melting rate and cooling rate 520mm TB6 titanium alloy

[0046] S1, Establish A two-dimensional axisymmetric finite element model of vacuum consumable arc melting of 520mm TB6 titanium alloy ingot was created, and the mesh was generated and the core process and physical property parameters were set.

[0047] The core process and physical property parameters set specifically include: the solid-liquid phase temperature of TB6 alloy, specific heat, thermal conductivity and dynamic viscosity in the range of 0~2200℃ as a function of temperature, as well as the radiation and convection heat transfer coefficients of the ingot side, and the effective distribution coefficients of Al and Fe elements.

[0048] S2, Determination of parameter gradient values ​​and calculation of deviation;

[0049] In step S2, the specific rules for the parameter gradient values ​​are as follows: when the melting rate is in the range of 6 kg / min to 10 kg / min, it is divided into a gradient of 2 kg / min; when the cooling rate is in the range of 0.10 K / s to 0.40 K / s, it is divided into a gradient of 0.09 K / s, forming a combination of multiple melting rate and cooling rate combinations that fully cover the range.

[0050] The specific process for calculating the deviation is as follows: Based on the finite element model of vacuum self-consuming arc melting of titanium alloy ingots established by S1, the parameter combinations are divided according to the specific rules for parameter gradient values, and the deviation of the average elemental composition under each parameter combination is calculated. The calculation formula is as follows:

[0051] ;

[0052] In the formula, This represents the element mass fraction at each grid node along the axial positions of the ingot edge, R / 2, and center. This represents the average mass fraction of elements in the entire ingot.

[0053] S3. The smelting process is divided into three stages, with each stage employing a targeted combination of optimal process parameters to ensure the deviation of the average elemental composition throughout the entire process. The melting rate should be within the range of 0.02 to 0.04 (based on production experience). Specifically, during the arc initiation phase, the melting rate is 7.5 kg / min and the cooling rate is 0.15 K / s to quickly establish the molten pool. After 40 minutes of arc initiation, the process transitions to a stable melting phase with a melting rate of 6.0 kg / min and a cooling rate of 0.38 K / s. During the feeding phase, the melting rate is gradually reduced to 0 kg / min, and the cooling rate is between 0.13 K / s and 0.18 K / s, with the total feeding time not exceeding 40 minutes.

[0054] S4 evaluates and analyzes the composition of the ingot at three longitudinal points and in its longitudinal section after smelting.

[0055] Chemical samples were taken from the head, middle and tail of the ingot for testing. It can be seen that the chemical composition is well uniform and the range of Al and Fe elements is less than 2000 ppm (as shown in Table 1).

[0056] Table 1. Preparation by synergistic control of melting rate and cooling rate 520mm specification TB6 titanium alloy (wt,%)

[0057]

[0058] Sampling method such as Figure 2 As shown, after removing the riser, samples were taken and tested at 60mm intervals along the radial and axial directions on a longitudinal sample piece 250mm from the head. This indicates good uniformity of chemical composition, with the Fe element variation within 1000ppm (e.g., ...). Figure 3 (As shown in the figure). This demonstrates that the method solves the ingot quality problem caused by mismatched process parameters in existing VAR smelting processes, improving ingot quality and performance while reducing production costs.

[0059] Example 2

[0060] Preparation by coordinated control of melting rate and cooling rate 920mm specification Ti80 titanium alloy

[0061] S1, Establish A two-dimensional axisymmetric finite element model of vacuum consumable arc melting of 920mm Ti80 titanium alloy ingot was created, and the mesh was generated and the core process and physical property parameters were set.

[0062] The core process and physical property parameters set specifically include: the solid-liquid phase temperature of Ti80 alloy, specific heat, thermal conductivity and dynamic viscosity in the range of 0~2200℃ as a function of temperature, as well as the radiation and convection heat transfer coefficients of the ingot side, and the effective distribution coefficients of Al, Zr, Mo and Nb elements.

[0063] S2, Determination of parameter gradient values ​​and calculation of deviation;

[0064] In step S2, the specific rules for the parameter gradient values ​​are as follows: when the melting rate is in the range of 20 kg / min to 23 kg / min, it is divided into a gradient of 2 kg / min; when the cooling rate is in the range of 0.20 K / s to 0.50 K / s, it is divided into a gradient of 0.09 K / s, forming a combination of multiple melting rate and cooling rate combinations that fully cover the range.

[0065] The specific process for calculating the deviation is as follows: Based on the finite element model of vacuum self-consuming arc melting of titanium alloy ingots established by S1, the parameter combinations are divided according to the specific rules for parameter gradient values, and the deviation of the average elemental composition under each parameter combination is calculated. The calculation formula is as follows:

[0066] ;

[0067] In the formula, This represents the element mass fraction at each grid node along the axial positions of the ingot edge, R / 2, and center. This represents the average mass fraction of elements in the entire ingot.

[0068] S3. The smelting process is divided into three stages, with each stage employing a targeted combination of optimal process parameters to ensure the deviation of the average elemental composition throughout the entire process. The value should be within the range of 0.03 to 0.05 (based on production experience). Specifically, during the arc initiation period, the melting rate is 23.0 kg / min and the cooling rate is 0.25 K / s to quickly establish the molten pool. After 80 minutes of arc initiation, the process transitions to a stable melting period with a melting rate of 21.0 kg / min and a cooling rate of 0.50 K / s. During the feeding period, the melting rate is gradually reduced to 0 kg / min, and the cooling rate is between 0.22 K / s and 0.35 K / s, with the total feeding time not exceeding 150 minutes.

[0069] S4 evaluates and analyzes the composition of the ingot at three longitudinal points and in its longitudinal section after smelting.

[0070] Chemical samples were taken from the head, middle and tail of the ingot for testing. It can be seen that the chemical composition is well uniform, and the range of Al, Zr, Mo and Nb elements is less than 3000 ppm (as shown in Table 2).

[0071] Table 2 Preparation by synergistic control of melting rate and cooling rate 520mm specification TB6 titanium alloy (wt,%)

[0072]

[0073] Sampling method such as Figure 2 As shown, after removing the riser, samples were taken and tested at 80mm intervals along the radial and axial directions on a longitudinal sample piece 300mm from the head. This indicates good uniformity of chemical composition, with the Mo element variation within 2000ppm (e.g., ...). Figure 4 (As shown in the figure). This demonstrates that the method solves the ingot quality problem caused by mismatched process parameters in existing VAR smelting processes, improving ingot quality and performance while reducing production costs.

[0074] Comparative Example 1: Preparation 920mm TC4 titanium alloy

[0075] Finite element software was not used to establish A 920mm TC4 titanium alloy melting mold was used, and the finished product was melted according to the production experience of relevant process personnel. The melting rate was kept constant at 12kg / min for the first 5000kg, and then reduced to 10kg / min. When the weight was 500kg, the melting rate was gradually reduced to enter the feeding period, with a total feeding time of not less than 180min. The cooling rate was always maintained at 0.4K / s. After melting, the composition of the ingot was evaluated and analyzed at three longitudinal points and in the longitudinal section.

[0076] Chemical samples were taken from the head, middle and tail of the ingot for testing. It can be seen that the uniformity of chemical composition is poor, and the range of Al and Fe elements is greater than 3000 ppm (as shown in Table 3).

[0077] Table 3 Preparation 920mm specification TC4 titanium alloy (wt,%)

[0078]

[0079] Sampling method such as Figure 2 As shown, after removing the riser, samples were taken at 80mm intervals along the radial and axial directions on a longitudinal sample piece 600mm from the head. The results showed that the Fe element at the edge of the ingot exhibited a significant solute deficiency and poor uniformity (e.g., Figure 5 (As shown).

[0080] Example 3

[0081] Preparation by coordinated control of melting rate and cooling rate 800mm specification Ti80 titanium alloy

[0082] S1, Establish A two-dimensional axisymmetric finite element model of vacuum consumable arc melting of 800mm Ti80 titanium alloy ingots was created, and the mesh was generated and the core process and physical property parameters were set.

[0083] The core process and physical property parameters set specifically include: the solid-liquid phase temperature of Ti80 alloy, specific heat, thermal conductivity and dynamic viscosity in the range of 0~2200℃ as a function of temperature, as well as the radiation and convection heat transfer coefficients of the ingot side, and the effective distribution coefficients of Al, Zr, Mo and Nb elements.

[0084] S2, Determination of parameter gradient values ​​and calculation of deviation;

[0085] In step S2, the specific rules for the parameter gradient values ​​are as follows: when the melting rate is in the range of 20 kg / min to 23 kg / min, it is divided into a gradient of 2 kg / min; when the cooling rate is in the range of 0.20 K / s to 0.50 K / s, it is divided into a gradient of 0.09 K / s, forming a combination of multiple melting rate and cooling rate combinations that fully cover the range.

[0086] The specific process for calculating the deviation is as follows: Based on the finite element model of vacuum self-consuming arc melting of titanium alloy ingots established by S1, the parameter combinations are divided according to the specific rules for parameter gradient values, and the deviation of the average elemental composition under each parameter combination is calculated. The calculation formula is as follows:

[0087] ;

[0088] In the formula, This represents the element mass fraction at each grid node along the axial positions of the ingot edge, R / 2, and center. This represents the average mass fraction of elements in the entire ingot.

[0089] S3. The smelting process is divided into three stages, with each stage employing a targeted combination of optimal process parameters to ensure the deviation of the average elemental composition throughout the entire process. The melting rate should be within the range of 0.04 to 0.06 (based on production experience). Specifically, during the arc initiation phase, the melting rate is 22.0 kg / min and the cooling rate is 0.20 K / s to quickly establish the molten pool. After 70 minutes of arc initiation, the process transitions to a stable melting phase with a melting rate of 20.0 kg / min and a cooling rate of 0.40 K / s. During the feeding phase, the melting rate is gradually reduced, and the cooling rate is between 0.35 K / s and 0.40 K / s, with the total feeding time not exceeding 120 minutes.

[0090] S4 evaluates and analyzes the composition of the ingot at three longitudinal points and in its longitudinal section after smelting.

[0091] Example 4

[0092] Preparation by coordinated control of melting rate and cooling rate 600mm TB6 titanium alloy

[0093] S1, Establish A two-dimensional axisymmetric finite element model of vacuum consumable arc melting of 600mm TB6 titanium alloy ingots was created, and the mesh was generated and the core process and physical property parameters were set.

[0094] The core process and physical property parameters set specifically include: the solid-liquid phase temperature of TB6 alloy, specific heat, thermal conductivity and dynamic viscosity in the range of 0~2200℃ as a function of temperature, as well as the radiation and convection heat transfer coefficients of the ingot side, and the effective distribution coefficients of Al and Fe elements.

[0095] S2, Determination of parameter gradient values ​​and calculation of deviation;

[0096] In step S2, the specific rules for the parameter gradient values ​​are as follows: when the melting rate is in the range of 20 kg / min to 23 kg / min, it is divided into a gradient of 2 kg / min; when the cooling rate is in the range of 0.20 K / s to 0.50 K / s, it is divided into a gradient of 0.09 K / s, forming a combination of multiple melting rate and cooling rate combinations that fully cover the range.

[0097] The specific process for calculating the deviation is as follows: Based on the finite element model of vacuum self-consuming arc melting of titanium alloy ingots established by S1, the parameter combinations are divided according to the specific rules for parameter gradient values, and the deviation of the average elemental composition under each parameter combination is calculated. The calculation formula is as follows:

[0098] ;

[0099] In the formula, This represents the element mass fraction at each grid node along the axial positions of the ingot edge, R / 2, and center. This represents the average mass fraction of elements in the entire ingot.

[0100] S3. The smelting process is divided into three stages, with each stage employing a targeted combination of optimal process parameters to ensure the deviation of the average elemental composition throughout the entire process. The melting rate is within the range of 0.05 to 0.06 (based on production experience). Specifically, during the arc initiation period, the melting rate is 21.0 kg / min and the cooling rate is 0.19 K / s to quickly establish the molten pool. After 70 minutes of arc initiation, the process transitions to a stable melting period with a melting rate of 20.0 kg / min and a cooling rate of 0.40 K / s. During the feeding period, the melting rate is gradually reduced, and the cooling rate is between 0.35 K / s and 0.40 K / s, with the total feeding time not exceeding 80 minutes.

[0101] S4 evaluates and analyzes the composition of the ingot at three longitudinal points and in its longitudinal section after smelting.

[0102] Example 5

[0103] Preparation by coordinated control of melting rate and cooling rate 800mm specification Ti80 titanium alloy

[0104] S1, Establish A two-dimensional axisymmetric finite element model of vacuum consumable arc melting of 800mm Ti80 titanium alloy ingots was created, and the mesh was generated and the core process and physical property parameters were set.

[0105] The core process and physical property parameters set specifically include: the solid-liquid phase temperature of Ti80 alloy, specific heat, thermal conductivity and dynamic viscosity in the range of 0~2200℃ as a function of temperature, as well as the radiation and convection heat transfer coefficients of the ingot side, and the effective distribution coefficients of Al, Zr, Mo and Nb elements.

[0106] S2, Determination of parameter gradient values ​​and calculation of deviation;

[0107] In step S2, the specific rules for the parameter gradient values ​​are as follows: when the melting rate is in the range of 20 kg / min to 23 kg / min, it is divided into a gradient of 2 kg / min; when the cooling rate is in the range of 0.20 K / s to 0.50 K / s, it is divided into a gradient of 0.09 K / s, forming a combination of multiple melting rate and cooling rate combinations that fully cover the range.

[0108] The specific process for calculating the deviation is as follows: Based on the finite element model of vacuum self-consuming arc melting of titanium alloy ingots established by S1, the parameter combinations are divided according to the specific rules for parameter gradient values, and the deviation of the average elemental composition under each parameter combination is calculated. The calculation formula is as follows:

[0109] ;

[0110] In the formula, This represents the element mass fraction at each grid node along the axial positions of the ingot edge, R / 2, and center. This represents the average mass fraction of elements in the entire ingot.

[0111] S3. The smelting process is divided into three stages, with each stage employing a targeted combination of optimal process parameters to ensure the deviation of the average elemental composition throughout the entire process. The value should be within the range of 0.04 to 0.05 (based on production experience). Specifically, during the arc initiation period, the melting rate is 22.0 kg / min and the cooling rate is 0.20 K / s to quickly establish the molten pool. After 70 minutes of arc initiation, the process transitions to a stable melting period with a melting rate of 20.0 kg / min and a cooling rate of 0.40 K / s. During the feeding period, the melting rate is gradually reduced, and the cooling rate is between 0.35 K / s and 0.40 K / s, with the total feeding time not exceeding 90 minutes.

[0112] S4 evaluates and analyzes the composition of the ingot at three longitudinal points and in its longitudinal section after smelting.

[0113] Example 6

[0114] Preparation by coordinated control of melting rate and cooling rate 800mm specification Ti80 titanium alloy

[0115] S1, Establish A two-dimensional axisymmetric finite element model of vacuum consumable arc melting of 800mm Ti80 titanium alloy ingots was created, and the mesh was generated and the core process and physical property parameters were set.

[0116] The core process and physical property parameters set specifically include: the solid-liquid phase temperature of Ti80 alloy, specific heat, thermal conductivity and dynamic viscosity in the range of 0~2200℃ as a function of temperature, as well as the radiation and convection heat transfer coefficients of the ingot side, and the effective distribution coefficients of Al, Zr, Mo and Nb elements.

[0117] S2, Determination of parameter gradient values ​​and calculation of deviation;

[0118] In step S2, the specific rules for the parameter gradient values ​​are as follows: when the melting rate is in the range of 20 kg / min to 23 kg / min, it is divided into a gradient of 2 kg / min; when the cooling rate is in the range of 0.20 K / s to 0.50 K / s, it is divided into a gradient of 0.09 K / s, forming a combination of multiple melting rate and cooling rate combinations that fully cover the range.

[0119] The specific process for calculating the deviation is as follows: Based on the finite element model of vacuum self-consuming arc melting of titanium alloy ingots established by S1, the parameter combinations are divided according to the specific rules for parameter gradient values, and the deviation of the average elemental composition under each parameter combination is calculated. The calculation formula is as follows:

[0120] ;

[0121] In the formula, This represents the element mass fraction at each grid node along the axial positions of the ingot edge, R / 2, and center. This represents the average mass fraction of elements in the entire ingot.

[0122] S3. The smelting process is divided into three stages, with each stage employing a targeted combination of optimal process parameters to ensure the deviation of the average elemental composition throughout the entire process. The melting rate is within the range of 0.04 to 0.06 (based on production experience). Specifically, during the arc initiation period, the melting rate is 22.0 kg / min and the cooling rate is 0.20 K / s to quickly establish the molten pool. After 85 minutes of arc initiation, the process transitions to a stable melting period with a melting rate of 19.0 kg / min and a cooling rate of 0.40 K / s. During the feeding period, the melting rate is gradually reduced, and the cooling rate is between 0.30 K / s and 0.40 K / s, with the total feeding time not exceeding 70 minutes.

[0123] S4 evaluates and analyzes the composition of the ingot at three longitudinal points and in its longitudinal section after smelting.

Claims

1. A method for the production of titanium alloy ingots with coordinated control of solidification and cooling rates, characterized in that, The specific steps are as follows: S1. Establish a finite element model for vacuum self-consuming electric arc melting of titanium alloy ingots, complete mesh generation, and set core process and physical property parameters. In step S1, the core process and physical property parameters set specifically include: solid-liquid phase temperature, specific heat, thermal conductivity and dynamic viscosity in the range of 0~2200℃ as a function of temperature, radiation and convection heat transfer coefficients of the ingot side, and effective distribution coefficients of each element. S2. Determination of parameter gradient values ​​and calculation of deviation; In step S2, the specific rules for taking parameter gradient values ​​are as follows: when the melting rate is in the range of 6 kg / min to 23 kg / min, it is divided into a gradient of 2 kg / min; when the cooling rate is in the range of 0.1 K / s to 0.67 K / s, it is divided into a gradient of 0.09 K / s, forming a combination of multiple melting rate and cooling rate combinations that fully cover the range. S3, the smelting process is divided into three stages of arc starting period, normal smelting period and feeding period, to ensure the average composition deviation of the whole process is in the range of 0.02~0.06; In step S3, a combination of a high melting rate of 7.5 kg / min to 23.0 kg / min and a medium-low cooling rate of 0.15 K / s to 0.25 K / s is used during the arc initiation period; In step S3, a medium-high melting rate of 6.0 kg / min to 21.0 kg / min and a medium cooling rate of 0.38 K / s to 0.50 K / s are used during the normal melting period; In step S3, the feeding period employs a cooling rate that gradually decreases from a melting rate to 0 kg / min and from 0.13 K / s to 0.40 K / s. S4. Evaluate and analyze the composition of the head, middle and tail longitudinal points and the longitudinal section composition of the ingot after melting.

2. The method for preparing titanium alloy ingots with synergistic control of melting rate and cooling rate according to claim 1, characterized in that, In step S1, the specifications of the finite element model for vacuum consumable arc melting of titanium alloy ingots are as follows: 520mm~ 920mm.

3. The method for preparing titanium alloy ingots with synergistic control of melting rate and cooling rate according to claim 1, characterized in that, In step S1, the established finite element model of vacuum consumable arc melting of titanium alloy ingots is a two-dimensional axisymmetric structure.

4. The method for preparing titanium alloy ingots with synergistic control of melting rate and cooling rate according to claim 1, characterized in that, In step S2, the specific process for calculating the deviation is as follows: Based on the finite element model of vacuum self-consuming arc melting of titanium alloy ingots established in S1, the parameter combinations are divided according to the specific rules for parameter gradient values, and the deviation of the average elemental composition under each parameter combination is calculated. The calculation formula is as follows: ； In the formula, This represents the element mass fraction at each grid node along the axial positions of the ingot edge, R / 2, and center. This represents the average mass fraction of elements in the entire ingot.

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