Electron beam cold bed melting energy control method for improving titanium alloy inclusion removal rate and application

Abstract

The invention discloses an electron beam cold bed smelting energy control method for improving the titanium alloy inclusion removal rate and application, and relates to the technical field of metallurgical smelting. The control method specifically comprises the steps that a process functional area of the electron beam cold bed furnace is divided into a smelting area A, a refining area B and a refining area C; wherein the smelting area A is subdivided into a central area A1, a middle lower area A2 and edge areas A3 and A4; the refining area B is subdivided into areas B1, B2 and B3 in the melt flowing direction; the refining area C is subdivided into areas C1, C2 and C3 in the melt flowing direction; energy differentiation distribution is carried out on the refining area B and the refining area C; the energy control method acts on the titanium alloy smelting process, the shape of a molten pool can be actively reconstructed, a thermal shock pit beneficial to sedimentation and an ascending flow field beneficial to floating interception are formed, and the removal rate of low-density inclusions is effectively increased.

Description

Technical Field

[0001] This invention relates to an energy control method and application for electron beam cold hearth melting to improve the removal rate of inclusions in titanium alloys, belonging to the field of metallurgical melting technology. Background Technology

[0002] Titanium and titanium alloys, with their high specific strength, excellent corrosion resistance, and biocompatibility, have found wide application in aerospace, chemical, and biomedical fields. In particular, with the development of aerospace propulsion towards higher thrust-to-weight ratios, the requirements for the purity of titanium alloy materials are becoming increasingly stringent. Even the smallest inclusions can become the origin of crack fatigue, leading to poor application performance. Therefore, producing high-quality, defect-free titanium alloy ingots has been a long-term goal of the metallurgical industry.

[0003] Currently, electron beam cold hearth melting (EBCHM) is the mainstream process for realizing high-density inclusions (HDI, such as WC, W) and low-density inclusions (LDI, such as TiN, TiO2) in titanium alloys, and it is also the only industrial production technology that can simultaneously and effectively realize both types of inclusions. Compared to vacuum arc melting (VAR), EBCHM maintains the flow of the melt in a water-cooled copper cold hearth by scanning with a high-energy-density electron beam. Its basic principle is: utilizing the density difference between different materials, high-density inclusions sink to the bottom of the cold hearth under gravity and are fixed by a solidified shell, while low-density inclusions float to the surface of the melt and are eliminated under high temperature and high vacuum conditions.

[0004] While EBCHM technology theoretically possesses extremely high purification capabilities, energy control during the smelting process faces significant challenges in actual industrial production. Related technologies and processes typically employ a "uniform surface" or a simple "energy distribution" scanning strategy, controlling the electron beam to scan uniformly across the cooling bed surface in an attempt to maintain a consistent surface temperature of the molten pool. However, with in-depth research into the thermal flow field behavior within the molten pool, the following significant technical defects and limitations have been identified in this crude "uniform distribution" control method: (1) Dead zones in the flow field and unidirectional flow restrict the removal of low-density inclusions: Under uniform energy distribution, the molten pool in the cooling bed often exhibits a "wide and shallow" shape. Due to the lack of necessary numerical simulations and production practice, the shallow depth of the molten pool (shallow solid-liquid interface) greatly hinders the settling and capture of high-density inclusions. When the melt flow rate is high, high-density particles with a large specific gravity (such as WC) have not yet had time to settle into the solidified shell, causing them to be easily "washed" out of the smelting zone with the main fluid and eventually enter the forming device, resulting in ingot defects.

[0005] (2) The energy uniformity strategy is difficult to drive an effective upward flow field: The removal efficiency of low-density inclusions (especially TiN with extremely high thermal stability) is highly dependent on their residence time on the surface of the high-temperature melt and whether they can be effectively transported to the surface. However, in conventional processes, the melt flow is often relatively slow, and there are even obvious "flow dead zones" near the corners of the cooling bed and the overflow port. Due to the lack of forced convection and an effective upward flow field, deep low-density inclusions are difficult to float to the surface and often pass directly through the refining zone in a suspended state (leading to removal failure). At the same time, if the surface residence time is insufficient, TiN-type hard inclusions cannot be completely decomposed or dissolved, resulting in a significant reduction in the refining effect.

[0006] (3) Energy control strategies cannot resolve the contradictions among various types of inclusions: There is an inherent contradiction between the elimination mechanisms of high-density inclusions and low-density inclusions: the former requires a deep molten pool and a low-velocity environment to facilitate sedimentation, while the latter requires high surface temperature and a specific upward flow field to promote its flotation separation and interception. Existing energy distribution strategies are essentially a "compromise" solution, which is difficult to balance these two completely different physical removal conditions, often resulting in one aspect being neglected and the other being difficult to achieve deep purification of all types of inclusions.

[0007] Related technologies typically employ multiple homogenized surfaces or simple energy distribution strategies to scan and control the electron beam. While this method is simple to operate and can maintain the basic melting process, its energy distribution is too planar and lacks the necessary flow field control mechanism. This results in fine, high-density inclusions (such as WC) and refractory, low-density inclusions (such as TiN) easily escaping with the melt, and the purity of the final titanium alloy ingot often only meets the minimum production standards.

[0008] Therefore, how to develop a new energy control method without increasing equipment costs, and actively reconstruct the molten pool flow field morphology through differentiated energy allocation, so as to significantly improve the removal rate of low-density inclusions while ensuring smelting efficiency, is a technical problem that urgently needs to be solved. Summary of the Invention

[0009] To address the shortcomings of related technologies, this invention provides a method and application for energy control in electron beam cold hearth melting to improve the removal rate of inclusions in titanium alloys. Applied to actual electron beam cold hearth melting equipment, this invention first divides the electron beam cold hearth into melting zone A, refining zone B, and refining zone C. A high-energy distribution scheme is adopted in melting zone A, while a differentiated energy distribution scheme is adopted in refining zones B and C. The process flow diagram is shown below. Figure 1 As shown, this invention utilizes a differentiated energy scanning strategy to actively reconstruct the flow field and geometry of the molten pool, thereby effectively improving the removal rate of both high- and low-density inclusions.

[0010] One objective of this invention is to provide a method for controlling the energy of electron beam cold hearth melting to improve the removal rate of inclusions in titanium alloys, specifically including the following steps: (1) The electron beam cooling bed is divided into three regions: melting zone A, refining zone B and refining zone C. Melting zone A is further divided into central region A1, lower middle region A2 and edge regions A3 and A4. Refining zone B is further divided into regions B1, B2 and B3 along the melt flow direction. Refining zone C is further divided into regions C1, C2 and C3 along the melt flow direction.

[0011] (2) Implement a center-focused energy distribution in the smelting zone A.

[0012] (3) Implement differentiated energy allocation for refining zone B and refining zone C.

[0013] Preferably, the method for subdividing the smelting zone A into a central region A1, a lower middle region A2, and edge regions A3 and A4 in step (1) is as follows: the smelting zone A connected to the feed inlet is subdivided, and the area of ​​the smelting zone A with the same width as the feed inlet along the melt flow direction is defined as the main smelting region. The main smelting region is divided into a central region A1 and a lower middle region A2 with equal areas along the direction perpendicular to the melt flow direction. The central region A1 is located on the side closer to the feed inlet. The parts of the smelting zone A located on the left and right sides of the main smelting region are defined as edge regions A3 and A4, respectively.

[0014] Preferably, the method for subdividing the refining zone B into regions B1, B2, and B3 in step (1) is as follows: the refining zone B is divided into three equal parts along the melt flow direction, which are regions B1, B2, and B3 in sequence; the method for subdividing the refining zone C into regions C1, C2, and C3 is as follows: the refining zone C is divided into three equal parts along the melt flow direction, which are regions C1, C2, and C3 in sequence.

[0015] Preferably, the method for implementing center-focused energy distribution in the smelting zone A in step (2) is as follows: energy is distributed according to the energy ratio of zone A as A1:A2:A3:A4=50%:20%:15%:15% or A1:A2:A3:A4=35%:35%:15%:15% or A1:A2:A3:A4=40%:20%:20%:20%.

[0016] More preferably, the method for implementing center-focused energy distribution in the smelting zone A in step (2) is as follows: energy is distributed according to the energy ratio of A1:A2:A3:A4=50%:20%:15%:15% or A1:A2:A3:A4=35%:35%:15%:15%.

[0017] Preferably, the method for implementing differentiated energy allocation in refining zone B in step (3) is as follows: based on the total energy of refining zone B and refining zone C, the total energy allocation ratio of refining zone B and refining zone C is 60%:40%.

[0018] Preferably, the method for implementing differentiated energy allocation between refining zones B and C in step (3) is as follows: energy is allocated according to the energy ratio of refining zones B and C as follows: B1:B2:B3:C1:C2:C3=30%:20%:10%:10%:13.3%:16.7% or B1:B2:B3:C1:C2:C3=30%:15%:15%:10%:13.3%:16.7% or B1:B2:B3:C1:C2:C3=30%:15%:15%:16.7%:13.3%:10% or B1:B2:B3:C1:C2:C3=30%:20%:10%:16.7%:13.3%:10%.

[0019] The second objective of this invention is to provide an application of an electron beam cold hearth melting energy control method for improving the removal rate of inclusions in titanium alloys, specifically including the following steps: Titanium alloy raw materials are fed into the melting zone of the electron beam cooling bed. Energy is distributed between the melting zone and the refining zone. The titanium alloy raw materials are melted in the melting zone to obtain a melt. The melt then flows continuously through the melting zone and the refining zone to complete the melting and refining in sequence. Finally, it enters the forming device (such as a forming machine) to solidify into an ingot.

[0020] Preferably, the titanium alloy raw material contains high-density inclusions and low-density inclusions, wherein the high-density inclusions are WC or W with a diameter of 30~300μm, and the low-density inclusions are TiN or TiO2 with a diameter of 30~300μm.

[0021] Preferably, the smelting conditions are: a smelting speed of 1400~2000 kg / h and a surface temperature of 1800~2000℃.

[0022] More preferably, the conditions are: a melting rate of 2000 kg / h and a surface temperature of 2000 °C.

[0023] More preferably, the titanium alloy raw material is TA1 or Ti-6Al-4V titanium alloy raw material.

[0024] The basis for implementing center-focused energy distribution in smelting zone A of this invention is as follows: reconstructing the electron beam cold bed molten pool, and forming a thermal shock cavity by implementing high energy input in the central region. High-density inclusions with a size exceeding 300 μm are captured at this stage and cannot escape due to gravity and inertia. The energy distribution is set based on the physical equilibrium equation, taking into account the chemical energy required to heat the solid raw material to the liquidus, and precisely matching the dynamic balance between the electron beam input heat and the thermal radiation loss calculated based on emissivity and condenser temperature factors. Combined with the mass transfer and flow field optimization requirements, and based on the Reynolds number analysis results, the energy distribution can drive the melt to form a specific vortex structure or velocity gradient, thereby extending the residence time of inclusions in the molten pool.

[0025] Mechanism of the invention: This invention achieves precise control over the morphology of the molten pool and the internal flow field by dynamically adjusting the energy distribution of the electron beam scanning on the surface of the cooling bed. The focus is on analyzing the coupling mechanism between energy distribution, molten pool morphology, flow field characteristics, and inclusion trajectory (capture rate / escape rate), providing a theoretical basis for optimizing inclusion removal processes.

[0026] This invention actively reconstructs the flow field and geometry of the molten pool through a differentiated electron beam energy scanning strategy. Its core mechanism lies in: Smelting Zone (Area A) – Deep Pit Capture of Heavy Inclusions: Through high-energy input focused at the center, a deep thermal impact cavity (central depression) is constructed in the smelting zone; using gravity and strong local disturbance, high-density inclusions with high specific gravity (such as WC, W) are efficiently intercepted and settled and locked at the bottom of the pit.

[0027] Refining Zone (B / C Zone) – Upward Slope Interception of Light Inclusions: By applying differentiated energy input along the melt flow direction, a rising slope-type melt pool with a deeper front and a shallower back is shaped. This structure forces the deep melt to flow upward, forming an upward flow field that drives low-density inclusions with low specific gravity (such as TiN) to float to the surface for removal, while significantly extending their residence time in the melt pool.

[0028] The beneficial effects of this invention are: Under the energy control method employed in this invention, the inclusion capture efficiency during the titanium alloy smelting process is significantly improved, particularly for high-density inclusions of WC (50 μm), W (200 μm), low-density inclusions of TiN (300 μm), and low-density inclusions of TiO2 (300 μm). This method effectively improves the overall inclusion removal efficiency, ensuring that the purity of the ingot meets the standard requirements, thereby increasing the utilization rate of titanium resources. Attached Figure Description

[0029] Figure 1 This is a process flow diagram of the present invention.

[0030] Figure 2 This is a schematic diagram of the fine division of the electron beam cooling bed region in Embodiment 1 of the present invention.

[0031] Figure 3 This is a diagram showing the temperature field and deep thermal impact cavity morphology of the smelting zone after a centrally focused energy distribution is formed in Embodiment 1 of the present invention.

[0032] Figure 4 This is a diagram of the temperature field and rising pillar-type molten pool morphology in the refining zone of Embodiment 1 of the present invention after the energy distribution is reduced. Detailed Implementation

[0033] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. In the embodiments and comparative examples of this invention, unless otherwise specified, all chemical reagents used were commercially available analytical grade reagents. The titanium alloy raw materials used in the embodiments and comparative examples of this invention contain high-density inclusions and low-density inclusions, wherein the high-density inclusions are WC or W with a diameter of 30-300 μm, and the low-density inclusions are TiN or TiO2 with a diameter of 30-300 μm. In the embodiments and comparative examples of the present invention, the method for subdividing the smelting zone A into a central region A1, a lower-middle region A2, and edge regions A3 and A4 is as follows: The smelting zone A connected to the feed inlet is subdivided. Along the melt flow direction, the area of ​​smelting zone A with the same width as the feed inlet is defined as the main smelting region. The main smelting region is then divided into a central region A1 and a lower-middle region A2 of equal area along the direction perpendicular to the melt flow. The central region A1 is located near the feed inlet. The portions of smelting zone A located to the left and right of the main smelting region are defined as edge regions A3 and A4, respectively. The method for subdividing the refining zone B into regions B1, B2, and B3 is as follows: The refining zone C into regions C1, C2, and C3 is as follows: The refining zone C is divided into regions C1, C2, and C3 along the melt flow direction. A detailed diagram of the subdivision is shown below. Figure 2 As shown.

[0034] Example 1 A method for controlling the energy of electron beam cold hearth melting to improve the removal rate of inclusions in titanium alloys, specifically including the following steps: (1) The process functional areas of the electron beam cold hearth furnace are divided into melting zone A, refining zone B and refining zone C; melting zone A is further subdivided into central zone A1, lower middle zone A2 and edge zones A3 and A4; refining zone B is further subdivided into zones B1, B2 and B3 along the melt flow direction; refining zone C is further subdivided into zones C1, C2 and C3 along the melt flow direction.

[0035] (2) Implement a center-focused energy distribution for the smelting zone A, and distribute the electron gun power according to the energy ratio of A1:A2:A3:A4=50%:20%:15%:15%.

[0036] (3) Implement energy reduction distribution in refining zones B and C. The power of the electron gun is distributed according to the total energy of refining zones B and C as a percentage of 100%, with the energy of refining zone B accounting for 60% and the energy of refining zone C accounting for 40%. Specifically, the energy distribution is B1:B2:B3:C1:C2:C3=30%:20%:10%:16.7%:13.3%:10%, so that the depth of the molten pool in zone B gradually becomes shallower along the direction of melt flow, forming an upward flow field; and an upward trend molten pool shape is formed in refining zone C.

[0037] In this embodiment, step (2) shows the temperature field and deep thermal shock cavity morphology of melting zone A. Figure 3 As shown, a distinct deep thermal shock pit (or central depression) is formed in the smelting zone. This structure effectively increases melt disturbance and promotes the settling and separation of high-density inclusions. The temperature field and rising pillar-type molten pool morphology of zones B and C in the refining zone of this embodiment are shown in the diagram below. Figure 4 As shown, under the combined effect of decreasing energy in regions B and C, the thickness of the sidewall in the refining zone gradually increases along the flow direction, and the depth of the molten pool gradually becomes shallower, creating an "upward trend" molten pool morphology, which in turn promotes the efficient floating of the melt carrying low-density inclusions to the surface.

[0038] To verify the effectiveness of the electron beam cold hearth melting energy control method in improving the inclusion removal rate of titanium alloys, the method was applied to melting titanium alloys and removing inclusions, specifically including the following steps: TA1 pure titanium raw material is fed into the feed inlet of the electron beam cooling bed. Energy distribution is implemented in the smelting zone (zone A) and refining zones (zones B and C) (energy ratio in zone A is A1:A2:A3:A4=50%:20%:15%:15%, and energy ratio in zones B and C is B1:B2:B3:C1:C2:C3=30%:20%:10%:16.7%:13.3%:10%). The TA1 pure titanium raw material is then processed in the smelting zone... The material is smelted at a melting rate of 2000 kg / h and a surface temperature of 2000℃ to obtain a melt. Under the action of a controlled flow field constructed by differential energy distribution, the melt flows continuously through the smelting zone and the refining zone. In the smelting zone, a deep thermal impact pit is constructed to promote the sedimentation and capture of high-density inclusions. In the refining zone, a gradient molten pool morphology is constructed to remove low-density inclusions. The melting and refining are completed in sequence, and finally the material enters the forming device for solidification to obtain the finished ingot. The electron beam cold hearth melting energy control method of this embodiment achieves a 92% capture rate for high-density inclusions (WC 50μm), a 96% capture rate for high-density inclusions (W 200μm), a 98% capture rate for low-density inclusions (TiN 300μm), and a 98% capture rate for low-density inclusions (TiO2 300μm). This is because this embodiment actively reconstructs the flow field and geometry of the molten pool through a differentiated energy scanning strategy. When using the control method of this embodiment to prepare titanium alloy ingots, the removal rate of high-density and low-density inclusions is significantly improved. The quality of the resulting ingots meets production standard requirements, thereby effectively improving the utilization rate of titanium resources.

[0039] Example 2 A method for controlling the energy of electron beam cold hearth melting to improve the removal rate of inclusions in titanium alloys, specifically including the following steps: (1) The process functional areas of the electron beam cold hearth furnace are divided into melting zone A, refining zone B and refining zone C; melting zone A is further subdivided into central zone A1, lower middle zone A2 and edge zones A3 and A4; refining zone B is further subdivided into zones B1, B2 and B3 along the melt flow direction; refining zone C is further subdivided into zones C1, C2 and C3 along the melt flow direction.

[0040] (2) Implement a center-focused energy distribution for the smelting zone A, and distribute the electron gun power according to the energy ratio of A1:A2:A3:A4=35%:35%:15%:15%.

[0041] (3) Implement differentiated energy allocation for refining zones B and C. The electron gun power is allocated as a percentage of the total energy of zones B and C, with zone B accounting for 60% and zone C accounting for 40%. Specifically, the energy allocation is B1:B2:B3:C1:C2:C3=30%:15%:15%:16.7%:13.3%:10%. This makes the depth of the molten pool in zone B gradually shallower along the direction of melt flow, forming an upward flow field and reconstructing the molten pool morphology in zone C.

[0042] In step (2) of this embodiment, a significant deep thermal impact pit (or central depression) is formed in the smelting zone A. This structure can effectively increase the disturbance of the melt and promote the settling and separation of high-density inclusions. In this embodiment, under the combined effect of differentiated energy distribution, the thickness of the sidewall of the refining zone gradually increases along the flow direction, and the depth of the molten pool gradually becomes shallower, thus constructing an "upward trend" molten pool shape, thereby prompting the melt to carry low-density inclusions to float efficiently to the surface.

[0043] To verify the effectiveness of the electron beam cold hearth melting energy control method in improving the inclusion removal rate of titanium alloys, the method was applied to melting titanium alloys and removing inclusions, specifically including the following steps: TA1 pure titanium raw material is fed into the feed inlet of the electron beam cooling bed. Energy distribution is implemented in the smelting zone (zone A) and refining zone (zones B and C) (energy ratio in zone A is A1:A2:A3:A4=35%:35%:15%:15%, energy ratio in zones B and C is B1:B2:B3:C1:C2:C3=30%:15%:15%:16.7%:13.3%:10%). In the smelting zone, the TA1 pure titanium raw material... The material is smelted at a melting rate of 2000 kg / h and a surface temperature of 2000℃ to obtain a melt. Under the action of a controlled flow field constructed by differential energy distribution, the melt flows continuously through the smelting zone and the refining zone. In the smelting zone, a deep thermal impact pit is constructed to promote the sedimentation and capture of high-density inclusions. In the refining zone, a gradient molten pool morphology is constructed to remove low-density inclusions. The melting and refining are completed in sequence, and finally the material enters the forming device for solidification to obtain the finished ingot. The electron beam cold hearth melting energy control method of this embodiment achieves a 90% capture rate for high-density inclusions (WC 50μm), a 94% capture rate for high-density inclusions (W 200μm), a 96% capture rate for low-density inclusions (TiN 300μm), and a 96% capture rate for low-density inclusions (TiO2 300μm). This is because this embodiment actively reconstructs the flow field and geometry of the molten pool through a differentiated energy scanning strategy. When using the control method of this embodiment to prepare titanium alloy ingots, the removal rate of high-density and low-density inclusions is significantly improved. The quality of the resulting ingots meets production standard requirements, thereby effectively improving the utilization rate of titanium resources.

[0044] Example 3 A method for controlling the energy of electron beam cold hearth melting to improve the removal rate of inclusions in titanium alloys, specifically including the following steps: (1) The process functional areas of the electron beam cold hearth furnace are divided into melting zone A, refining zone B and refining zone C; melting zone A is further subdivided into central zone A1, lower middle zone A2 and edge zones A3 and A4; refining zone B is further subdivided into zones B1, B2 and B3 along the melt flow direction; refining zone C is further subdivided into zones C1, C2 and C3 along the melt flow direction.

[0045] (2) Implement a center-focused energy distribution for the smelting zone A, and distribute the electron gun power according to the energy ratio of A1:A2:A3:A4=40%:20%:20%:20%.

[0046] (3) Implement differentiated energy allocation for refining zones B and C. The electron gun power is allocated as a percentage of the total energy of zones B and C, with zone B accounting for 60% and zone C accounting for 40%. Specifically, the energy allocation is B1:B2:B3:C1:C2:C3=30%:20%:10%:10%:13.3%:16.7%. This makes the depth of the molten pool in zone B gradually shallower along the direction of melt flow, forming an upward flow field. An upward trend molten pool shape is formed in zone C.

[0047] In step (2) of this embodiment, a flexible, adjustable solidified shell thickness is formed in melting zone A, expanding the effective molten pool width. In this embodiment, refining zone B implements decreasing energy distribution, and refining zone C implements increasing energy distribution. This method drives low-density inclusions to float to the surface of the molten pool and utilizes the high-temperature, high-vacuum environment on the surface to generate a decomposition reaction. At the same time, by adjusting the energy density, the temperature of the refining bed is maintained within the superheat window of 30-50℃, ensuring a high degree of consistency between the melt composition and temperature.

[0048] To verify the effectiveness of the electron beam cold hearth melting energy control method in improving the inclusion removal rate of titanium alloys, the method was applied to melting titanium alloys and removing inclusions, specifically including the following steps: Ti-6Al-4V titanium alloy raw material is fed into the feed inlet of the electron beam cooling bed. Energy distribution is implemented in the melting zone (zone A) and refining zones (zones B and C) (energy ratio in zone A is A1:A2:A3:A4=40%:20%:20%:20%, energy ratio in zones B and C is B1:B2:B3:C1:C2:C3=30%:20%:10%:10%:13.3%:16.7%). In the melting zone, Ti-6Al... -4V titanium alloy raw material is smelted at a melting rate of 1800 kg / h and a surface temperature of 1800℃ to obtain a melt. Under the action of a controlled flow field constructed by differential energy distribution, the melt flows continuously through the melting zone and the refining zone. In the melting zone, a deep thermal shock pit is constructed to promote the sedimentation and capture of high-density inclusions. In the refining zone, a gradient molten pool morphology is constructed to remove low-density inclusions. The melting and refining are completed in sequence, and finally the melt enters the forming device for solidification to obtain the finished ingot. The electron beam cold hearth melting energy control method of this embodiment achieves a capture rate of 89% for high-density inclusions (WC 50μm), 92% for high-density inclusions (W 200μm), 92% for low-density inclusions (TiN 300μm), and 93% for low-density inclusions (TiO2 300μm). This is because this embodiment actively reconstructs the flow field and geometry of the molten pool through a differentiated energy scanning strategy. When using the control method of this embodiment to prepare titanium alloy ingots, the removal rate of high-density and low-density inclusions is significantly improved. The quality of the resulting ingots meets production standard requirements, thereby effectively improving the utilization rate of titanium resources.

[0049] Example 4 A method for controlling the energy of electron beam cold hearth melting to improve the removal rate of inclusions in titanium alloys, specifically including the following steps: (1) The process functional areas of the electron beam cold hearth furnace are divided into melting zone A, refining zone B and refining zone C; melting zone A is further subdivided into central zone A1, lower middle zone A2 and edge zones A3 and A4; refining zone B is further subdivided into zones B1, B2 and B3 along the melt flow direction; refining zone C is further subdivided into zones C1, C2 and C3 along the melt flow direction.

[0050] (2) Implement a center-focused energy distribution for the smelting zone A, and distribute the electron gun power according to the energy ratio of A1:A2:A3:A4=35%:35%:15%:15%.

[0051] (3) Implement differentiated energy allocation for refining zones B and C. The electron gun power is allocated as a percentage of the total energy of zones B and C, with zone B accounting for 60% and zone C accounting for 40%. Specifically, the energy allocation is B1:B2:B3:C1:C2:C3=30%:15%:15%:10%:13.3%:16.7%. This makes the depth of the molten pool in zone B gradually shallower along the direction of melt flow, forming an upward flow field. An upward trend molten pool shape is formed in zone C.

[0052] In step (2) of this embodiment, a significant deep thermal shock pit (or central depression) is formed in the melting zone A. This structure can effectively increase melt disturbance and promote the settling and separation of high-density inclusions. In this embodiment, the refining zones B and C implement differentiated energy distribution, which not only maintains the continuous accuracy of the sidewall solidified shell thickness, but also ensures the stability of the rising flow field throughout the entire process by reconstructing the molten pool cross-section, thereby effectively eliminating the flow dead zone at the bottom corner and sidewall of the refining zone. The precise adjustment of the energy matching gap improves the inclusion rate while ensuring the stability of the ingot and the microstructure composition.

[0053] To verify the effectiveness of the electron beam cold hearth melting energy control method in improving the inclusion removal rate of titanium alloys, the method was applied to melting titanium alloys and removing inclusions, specifically including the following steps: Ti-6Al-4V titanium alloy raw material is fed into the feed inlet of the electron beam cooling bed. Energy distribution is implemented in the melting zone (zone A) and refining zones (zones B and C) (energy ratio in zone A is A1:A2:A3:A4=35%:35%:15%:15%, energy ratio in zones B and C is B1:B2:B3:C1:C2:C3=30%:15%:15%:10%:13.3%:16.7%). In the melting zone, Ti-6Al... -4V titanium alloy raw material is smelted at a melting rate of 1400 kg / h and a surface temperature of 1900℃ to obtain a melt. Under the action of a controlled flow field constructed by differential energy distribution, the melt flows continuously through the melting zone and the refining zone. In the melting zone, a deep thermal shock pit is constructed to promote the sedimentation and capture of high-density inclusions. In the refining zone, a gradient molten pool morphology is constructed to remove low-density inclusions. The melting and refining are completed in sequence, and finally the melt enters the forming device for solidification to obtain the finished ingot. The electron beam cold hearth melting energy control method of this embodiment achieves a capture rate of 88.5% for high-density inclusions (WC 50μm), 90% for high-density inclusions (W 200μm), 90% for low-density inclusions (TiN 300μm), and 91% for low-density inclusions (TiO2 300μm). This is because this embodiment actively reconstructs the flow field and geometry of the molten pool through a differentiated energy scanning strategy. When using the control method of this embodiment to prepare titanium alloy ingots, the removal rate of high-density and low-density inclusions is significantly improved. The quality of the resulting ingots meets production standard requirements, thereby effectively improving the utilization rate of titanium resources.

[0054] Comparative Example 1 An energy control method for electron beam cold bed melting specifically includes the following steps: (1) The process functional areas of the electron beam cooling bed are divided into melting zone A, refining zone B and refining zone C; melting zone A is further subdivided into central zone A1, lower middle zone A2 and edge zone A3 and A4; refining zone B is further subdivided into zone B1, B2 and B3 along the melt flow direction; refining zone C is further subdivided into zone C1, C2 and C3 along the melt flow direction.

[0055] (2) Implement uniform energy distribution in the smelting zone A, and distribute the electron gun power according to the energy ratio of A1:A2:A3:A4=25%:25%:25%:25%.

[0056] (3) Implement uniform energy distribution in refining zone B and refining zone C, and distribute the electron gun power equally to zones B1, B2, B3, C1, C2 and C3 according to the total energy of zones B and C as a percentage of 100%.

[0057] To verify the effectiveness of the comparative electron beam cold hearth melting energy control method in improving the inclusion removal rate of titanium alloys, the comparative electron beam cold hearth melting energy control method was applied to melting titanium alloys and removing inclusions, specifically including the following steps: TA1 titanium alloy raw material is fed into the feed inlet of an electron beam cooling bed. Energy is allocated to the melting zone (zone A) and refining zones (zones B and C) (energy ratio in zone A is A1:A2:A3:A4 = 25%:25%:25%:25%, energy is evenly distributed in zones B and C, and the total energy is 100% by percentage). In the melting zone, the TA1 titanium alloy raw material is melted at a melting rate of 2000 kg / h and a surface temperature of 2000℃ to obtain a melt. The melt then continuously flows through the melting zone and refining zone, completing the melting and refining processes sequentially. Finally, it enters the forming device for solidification to obtain the finished ingot. The molten pool morphology formed by the electron beam cooling bed melting energy control method in this comparative example is flat (or relatively simple), without the formation of deep thermal impact pits or gradient upflow characteristics. The comparative example of electron beam cold bed melting energy control method achieved a capture rate of 88% for high-density inclusions (WC 50μm), 88% for high-density inclusions (W 200μm), 85% for low-density inclusions (TiN 300μm), and 86% for low-density inclusions (TiO2 300μm). This is because the uniform energy distribution strategy adopted in this comparative example resulted in an overly flat overall morphology of the molten pool. In the melting zone, an effective deep thermal impact pit was not formed, resulting in a lack of geometric traps for the high-density inclusions to settle and be captured. In the refining zone, the lack of an energy gradient prevented the formation of an upward flow field, which could not drive the deep low-density inclusions to float efficiently to the surface, thus resulting in poor overall inclusion removal effect.

[0058] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for controlling the energy of electron beam cold hearth melting to improve the removal rate of inclusions in titanium alloys, characterized in that, Specifically, the following steps are included: (1) The electron beam cooling bed is divided into three regions: smelting zone A, refining zone B, and refining zone C. Smelting zone A is further divided into central region A1, lower middle region A2, and edge regions A3 and A4. Refining zone B is further divided into regions B1, B2, and B3 along the melt flow direction. Refining zone C is further divided into regions C1, C2, and C3 along the melt flow direction. (2) Implement a center-focused energy distribution for smelting zone A; (3) Implement differentiated energy allocation for refining zone B and refining zone C.

2. The method for controlling the energy of electron beam cold hearth melting to improve the removal rate of inclusions in titanium alloys according to claim 1, characterized in that, The method for subdividing the smelting zone A into a central region A1, a lower middle region A2, and edge regions A3 and A4 in step (1) is as follows: The smelting zone A connected to the feed inlet is subdivided. The area of ​​the smelting zone A with the same width as the feed inlet along the melt flow direction is defined as the main smelting region. The main smelting region is divided into a central region A1 and a lower middle region A2 with equal areas along the direction perpendicular to the melt flow direction. The central region A1 is located on the side closer to the feed inlet. The parts of the smelting zone A located on the left and right sides of the main smelting region are defined as edge regions A3 and A4, respectively.

3. The electron beam cold hearth melting energy control method for improving the removal rate of inclusions in titanium alloys according to claim 1, characterized in that, The method for subdividing the refining zone B into regions B1, B2, and B3 in step (1) is as follows: divide the melt flow direction into three equal parts, which are regions B1, B2, and B3 in sequence; the method for subdividing the refining zone C into regions C1, C2, and C3 is as follows: divide the melt flow direction into three equal parts, which are regions C1, C2, and C3 in sequence.

4. The method for controlling the energy of electron beam cold hearth melting to improve the removal rate of inclusions in titanium alloys according to claim 1, characterized in that, The method for implementing center-focused energy distribution in the smelting zone A in step (2) is as follows: energy is distributed according to the energy ratio of zone A as A1:A2:A3:A4=50%:20%:15%:15% or A1:A2:A3:A4=35%:35%:15%:15% or A1:A2:A3:A4=40%:20%:20%:20%.

5. The method for controlling the energy of electron beam cold hearth melting to improve the removal rate of inclusions in titanium alloys according to claim 1, characterized in that, In step (3), the total energy of refining zone B and refining zone C is used as the basis, and the total energy distribution ratio of refining zone B and refining zone C is 60%:40%.

6. The method for controlling the energy of electron beam cold hearth melting to improve the removal rate of inclusions in titanium alloys according to claim 1, characterized in that, The method for implementing differentiated energy allocation in refining zones B and C in step (3) is as follows: energy is allocated according to the energy ratio of refining zones B and C as follows: B1:B2:B3:C1:C2:C3=30%:20%:10%:10%:13.3%:16.7% or B1:B2:B3:C1:C2:C3=30%:15%:15%:10%:13.3%:16.7% or B1:B2:B3:C1:C2:C3=30%:15%:15%:16.7%:13.3%:10% or B1:B2:B3:C1:C2:C3=30%:20%:10%:16.7%:13.3%:10%.

7. The application of the electron beam cold hearth melting energy control method for improving the removal rate of inclusions in titanium alloys as described in claim 1, characterized in that, Specifically, the following steps are included: Titanium alloy raw materials are fed into the melting zone of the electron beam cooling bed. Energy is distributed between the melting zone and the refining zone. The titanium alloy raw materials are melted in the melting zone to obtain a melt. The melt then flows continuously through the melting zone and the refining zone to complete the melting and refining in sequence. Finally, it enters the forming device to solidify into an ingot.

8. The application of the electron beam cold hearth melting energy control method for improving the removal rate of inclusions in titanium alloys according to claim 7, characterized in that, The titanium alloy raw material contains high-density inclusions and low-density inclusions, wherein the high-density inclusions are WC or W with a diameter of 30~300μm, and the low-density inclusions are TiN or TiO2 with a diameter of 30~300μm.

9. The application of the electron beam cold hearth melting energy control method for improving the removal rate of inclusions in titanium alloys according to claim 7, characterized in that, The smelting conditions are: smelting speed of 1400~2000 kg / h and surface temperature of 1800~2000℃.

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