Titanium alloy beta-phase region heating method based on finite element analog simulation

Abstract

The invention relates to a titanium alloy beta-phase region heating method based on finite element analog simulation. The titanium alloy beta-phase region heating method comprises the steps of blank preparation, blank heating test, blank surface convective heat transfer coefficient back calculation, establishment of heating models of titanium alloy workpieces with different thicknesses, setting of heating systems of the titanium alloy workpieces with different thicknesses and the like. According to the method, the heat exchange coefficient of the heating furnace can be effectively obtained, so that a visual heating process scheme is established, the temperature field in the beta-phase region heating process of blanks with different thicknesses is accurately calculated, the alloy is ensured to be thoroughly heated, the high surface oxidation degree and grain deterioration and growth are avoided, and the product quality is improved. The problem that the heating duration of a titanium alloy single-phase region is difficult to accurately control is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of titanium processing, and in particular to a titanium alloy β-phase region heating method based on finite element simulation. Background Art

[0002] Titanium began to develop in the 1950s and is known as the "third metal" after steel and aluminum. Titanium alloys have low density, high strength, excellent corrosion resistance and high-temperature durability. They are often used as important components and are widely used in aerospace, marine ships, national defense and military industry, weapons and energy, chemical and medical fields.

[0003] The preparation of titanium alloy plates, bars, wires and many other products requires a strict heat treatment system. Before forging, β-treatment is often used to heat the blank to above the phase transition point, thereby improving the metal fluidity, reducing deformation resistance and mold wear, etc. However, the heating time must be strictly controlled. If the heating time is too short, the blank cannot be fully heated through, resulting in a further increase in the temperature gradient during subsequent forging deformation; if the heating time is too long, the surface of the blank is severely oxidized, and the β grains grow rapidly, resulting in β embrittlement and reduced plasticity. On the other hand, there must be certain differences in the heat-through time of blanks of different thicknesses. The preheating temperature, heating time, and holding time need to be accurately calculated according to the blank size to ensure their specification and rationality. To this end, there is an urgent need for a method to solve the deficiencies in the existing technology. The relevant existing technologies are as follows:

[0004] Invention patent application number CN 201510034559.0 discloses a method for heating titanium alloy billets. This method provides a complementary heating method using a resistance furnace and a gas furnace, thereby avoiding hydrogen embrittlement and oxidation of the titanium material caused by prolonged heating. However, this method does not provide the heat-through time for billets of different thicknesses or the basis for its formulation.

[0005] The invention patent with application number CN 202211366932.9 discloses a formulaic control method for the shortest holding time of TC17 titanium alloy beta forging heating, which provides a minimum time for TC17 titanium alloy beta heating and its calculation method; however, whether this method is applicable to other titanium alloy grades is still unknown, and the maximum calculated thickness does not exceed 510mm, and the scope of implementation is limited.

[0006] The invention patent with application number CN 202311256466.3 discloses a heating method for large-thickness titanium alloy slabs, which provides a heating system for large-thickness titanium alloy slabs and optimizes the temperature uniformity of the slabs during the heating process; however, the heating system of this method has many steps, the process is cumbersome and complicated, and the heating effect for non-large-thickness slabs is still unclear.

[0007] The document titled "Finite Element Study on Thermal-Flow Coupling of Heating Furnace Heating Process" proposes a heating process model for TC4 plates before rolling, which can effectively calculate the temperature field and flow field during the heating process of the billet; however, this method is only applicable to gas furnace heating. Compared with electric heating furnaces, the heating process has many influencing parameters, and the billet temperature distribution is not constant.

[0008] The paper, titled "Finite Element Model of TC17 Titanium Alloy Heating Process," proposed a TC17 heating model based on finite element simulation calculations and performed grain size verification; however, this method did not provide specific calculations and guidance for the actual heating process of TC17, and was limited to the establishment and verification process of the finite element simulation model.

[0009] In summary, the above-mentioned existing technologies all have certain limitations and shortcomings, and there is still room for further improvement and perfection. Summary of the Invention

[0010] In response to the above problems, the purpose of the present invention is to provide a β-phase zone heating method for titanium alloys based on finite element simulation, which can effectively obtain the heat transfer coefficient of the heating furnace, establish a visual heating process plan, and accurately calculate the temperature field during the β-phase zone heating process of billets of different thicknesses, ensuring that the alloy is heated through while avoiding high surface oxidation and grain deterioration and growth, and can effectively solve the problem of difficult to accurately control the heating time of the single-phase zone of titanium alloys.

[0011] The technical solution adopted in the present invention is as follows:

[0012] The present invention proposes a method for heating the titanium alloy β phase region based on finite element simulation, comprising the following steps:

[0013] Step S1: Prepare three square titanium alloy billets, labeled 1#-3#, and prepare several thermocouples; mark drilling positions ①-⑤ on the surface of each billet, where ① is the center of 1 / 4 width from one long side, ② is the center of 1 / 4 length from one wide side, ③ is the center of 1 / 4 length from ②, and ④ is the center of the billet; ⑤ is the center of 1 / 4 width from the other long side; complete drilling at positions ①-⑤ of each billet, and connect the thermocouples one by one to the bottom of the blind hole positions ①-⑤ of the billet;

[0014] Step S2: Complete the heating test of 1#-3# titanium alloy billets by heating at room temperature in a furnace until the temperature reaches above 1100°C, with a heating rate of 4-8°C / min. Use a patrol meter to record the temperature rise curves of different billets respectively, and set the temperature collection cycle range from 2min to 10min / time;

[0015] Step S3: Complete the back calculation of the surface convection heat transfer coefficient at different positions of the furnace, and repeatedly debug the model until the error between the simulated temperature rise curve value and the measured value is within 5°C;

[0016] Step S4: Establish heating models for titanium alloy workpieces of different thicknesses, compare the calculation results of 1#-3# in step S3, and take the minimum calculated value among the three as the surface convection heat transfer coefficient of the current heating model; set the thermal radiation coefficient to 0.6-0.8, and complete the temperature field calculation of the titanium alloy workpiece under different heating systems;

[0017] Step S5: Based on the temperature field calculation results, the preheating, heating, and holding times required for the minimum heat penetration of the titanium alloy workpiece are analyzed, and then the heating system for titanium alloy workpieces of different thicknesses is set. The minimum temperature of the core of the billet is greater than or equal to the heating temperature -3°C, and finally the heating system for the titanium alloy β phase region is formulated.

[0018] Furthermore, in step S1, the length of the square blank is L, the width is W, and the thickness is D, and the punching depths of ①-⑤ are recorded as M1-M5 respectively; wherein L=2W=2D≥280mm, and M1=M4=M5=0.5D, M3=0.25D, and M2=0.125D;

[0019] Furthermore, in step S1, the thermocouple is an N-type thermocouple with a diameter of 6-8 mm, and the designed drilling diameter is 8-10 mm.

[0020] Furthermore, in step S1, thermal insulation cotton is used to seal the gap between the blind hole and the thermocouple wire, and a thermocouple is additionally prepared to measure the ambient temperature of the blank.

[0021] Furthermore, in step S2, the length of the heating furnace is Amm and the width is Bmm; the coordinates of the 1#-3# billets are set to (x1, y1), (x2, y2), and (x3, y3), respectively; among which (x1, y1) = (0, 0); (x2, y2) = [(B / 2)-50, 0]; (x3, y3) = [0, (A / 2)-50].

[0022] Furthermore, in step S3, the surface convection heat transfer coefficient of samples 1#-3# was calculated using the Deform 3D finite element simulation software and the 3D Inverse Heat module. The surface convection heat transfer coefficient was output every 100°C from 0 to 1100°C, and the calculated value was within the range of 0.01-0.4N / s / mm / °C.

[0023] Furthermore, in step S4, the titanium alloy workpiece is of α-type or (α+β)-type titanium alloy.

[0024] Furthermore, in step S5, the heating regime for titanium alloy workpieces of different thicknesses is as follows:

[0025] When the workpiece thickness is 200-400mm, the preheating time is 80-100min, the heating time is 90-120min, and the holding time is 120-180min;

[0026] When the workpiece thickness is 400-600mm, the preheating time is 110-130min, the heating time is 120-150min, and the holding time is 150-180min;

[0027] When the workpiece thickness is 600-750mm, the preheating time is 140-160min, the heating time is 150-180min, and the holding time is 180-240min;

[0028] When the workpiece thickness is 750-900mm, the preheating time is 170-190min, the heating time is 180-240min, and the holding time is 240-300min.

[0029] Furthermore, in step S5, the charging temperature of the heating system is 800°C-850°C, the heating temperature is 50-150°C above the phase transition point temperature of the titanium alloy, and the workpiece thickness is the thickness dimension of the workpiece at the maximum cross-sectional area.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention can effectively obtain the heat transfer coefficient of the heating furnace, establish a visual heating process plan, and accurately calculate the temperature field during the heating process of the β phase region of billets with different thicknesses, ensuring that the alloy is heated through while effectively avoiding problems such as high surface oxidation and grain deterioration and growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the size design of the titanium billet used in the test of the present invention;

[0033] Figure 2 This is a schematic diagram of a titanium ingot heated for testing in the present invention;

[0034] Figure 3 This is a schematic diagram of the heating furnace distribution position in the present invention;

[0035] Figure 4 This is a schematic diagram of the verification of the simulated and actual temperature rise curves in the present invention;

[0036] Figure 5 Schematic diagram of the relationship between the temperature and time of each stage of the heating system in the present invention;

[0037] Figure 6 This is a schematic diagram of the cloud map distribution of the temperature field inside the titanium billet in Example 1. DETAILED DESCRIPTION

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] The present invention proposes a method for heating the titanium alloy β phase region based on finite element simulation, which specifically includes the following steps:

[0040] Step S1: Prepare three square titanium alloy billets, labeled 1#-3#, and prepare several thermocouples; mark drilling positions ①-⑤ on the upper surface of each billet;

[0041] Drilling location Figure 1-2 As shown, ① is the center of 1 / 4 width from one long side, ② is the center of 1 / 4 length from one wide side, ③ is the center of 1 / 4 length from ②, and ④ is the center of the blank; ⑤ is the center of 1 / 4 width from the other long side. Subsequently, blind holes are drilled in positions ①-⑤ of each blank, and thermocouples are connected to the bottom of the blind holes in each blank one by one. The gap between the blind holes and the thermocouple wires is sealed with thermal insulation cotton, and additional thermocouples are prepared to measure the ambient temperature of the blank.

[0042] Among them, the thermocouple is an N-type thermocouple with a diameter of 6-8 mm, and the punching diameter of the designed blank is 8-10 mm;

[0043] The length of each square blank is L, the width is W, and the thickness is D. The punching depths of ①-⑤ are recorded as M1-M5 respectively; among which L=2W=2D≥280mm, and M1=M4=M5=0.5D, M3=0.25D, and M2=0.125D.

[0044] Step S2: Complete the heating test of 1#-3# titanium alloy billets by heating at room temperature in a furnace until the temperature reaches above 1100°C, with a heating rate of 4-8°C / min. Use a patrol meter to record the temperature rise curves of different billets respectively, and set the temperature collection cycle range from 2min to 10min / time;

[0045] Among them, the length of the heating furnace is Amm and the width is Bmm; Figure 3 As shown, the coordinates of 1#-3# blanks are set to (x1, y1), (x2, y2), and (x3, y3), respectively; among which (x1, y1) = (0, 0); (x2, y2) = [(B / 2)-50, 0]; (x3, y3) = [0, (A / 2)-50].

[0046] Step S3: Complete the back calculation of the convection heat transfer coefficient of the billet surface at different furnace positions, and repeatedly debug the model until the error between the simulated temperature rise curve value and the measured value is within 5°C. Figure 4 As shown;

[0047] The Deform 3D finite element simulation software and the 3D Inverse Heat module were used to calculate the surface convection heat transfer coefficient of billets 1#-3#. The surface convection heat transfer coefficient was output every 100°C from 0 to 1100°C, and the calculated values ​​were within the range of 0.01-0.4N / s / mm / °C.

[0048] Step S4: Establish a heating model for titanium alloy workpieces of different thicknesses, compare the calculation results of 1#-3# in step S3, and take the minimum calculated value among the three as the surface convection heat transfer coefficient of the current heating model; set the thermal radiation coefficient to 0.6-0.8, and complete the temperature field calculation of the titanium alloy workpiece under different heating systems; among which, the titanium alloy workpiece category is α-type or (α+β)-type titanium alloy.

[0049] Step S5: Based on the temperature field calculation results, the preheating, heating, and holding times required for the minimum heat penetration of the titanium alloy workpiece are analyzed, and then the heating system for titanium alloy workpieces of different thicknesses is set. The minimum temperature of the core of the billet is greater than or equal to the heating temperature -3°C, and finally the heating system for the titanium alloy β phase region is formulated.

[0050] The heating system for titanium alloy workpieces of different thicknesses is shown in the following table:

[0051] Workpiece thickness / mm Preheating time / min Heating time / min Holding time / min 200～400 80～90 90～120 120～180 400～600 110～130 120～150 150～180 600～750 140～160 150～180 180～240 750～900 170～190 180～240 240～300

[0052] like Figure 5 As shown, A is the preheating stage; B is the heating stage; C is the insulation stage; the furnace charging temperature is 800℃-850℃, the heating temperature is above the phase transformation point of titanium alloy (50~150)℃, and the workpiece thickness is the thickness dimension under the maximum cross-sectional area of ​​the workpiece.

[0053] Traditional methods for designing heating schedules often use empirical formulas based on billet thickness. During the actual heating process, thermocouples only record changes in the ambient temperature within the furnace and are unable to measure the temperature rise within the billet. Therefore, the core principle of this invention is to collect the internal temperature rise of the billet, inversely calculate the heat transfer coefficient of the heating furnace through numerical simulation, and establish a heating model after parameter verification and verification. This allows for precise calculations of the preheating, heating, and temperature equalization stages during the heating process for billets of different thicknesses, thereby formulating a reasonable heating schedule and optimizing the deficiencies of traditional empirical formula design.

[0054] The present invention will be further described below by means of specific embodiments:

[0055] Example 1:

[0056] Step S1: Prepare three square titanium alloy billets, marked as 1# to 3#. The size of the titanium billets is as follows: Figure 1 . Prepare several thermocouples, complete the drilling of the blank at positions ①~⑤, connect the thermocouples to the blank at positions ①~⑤ blind holes, use insulation cotton to seal the gaps between the blind holes and the thermocouple wires, and prepare additional thermocouples to measure the ambient temperature of the blank. In step S1, the titanium alloy material is a common low-cost titanium metal such as TC4. It is stipulated that the length of the square billet is 280mm, the width is 140mm, and the thickness is 140. The drilling depths of ①~⑤ are respectively recorded as M1~M5; wherein L=2W=2D≥280mm, and M1=M4=M5=70mm, M3=35mm, and M2=17.5mm; the thermocouple is an N-type thermocouple with a diameter of 8mm, and the designed drilling diameter is 10mm.

[0057] Step S2: Complete the heating test of 1#~3# titanium alloy billets. The heating method is room temperature furnace heating until the temperature reaches above 1100℃. The heating rate is 5℃ / min. The temperature rise curves of different billets are recorded separately using a patrol meter. The temperature acquisition cycle setting range is 2minn / time. The length of the heating furnace in step S2 is 3000mm and the width is 2000mm. The coordinates of 1#~3# billets are set to (x1, y1), (x2, y2), and (x3, y3), respectively. Among them, (x1, y1) = (0, 0); (x2, y2) (950, 0); (x3, y3) = (0, 1450). That is, place 1#~3# billets in the center, center edge, and center bottom of the heating furnace, respectively. As follows Figure 2 、 Figure 3 shown.

[0058] Step S3: Complete the back calculation of the surface convection heat transfer coefficient at different furnace positions, and repeatedly debug the model until the error between the simulated temperature rise curve value and the measured value is within 5°C, as follows Figure 4 In step S3, the surface convection heat transfer coefficient of samples 1# to 3# is calculated using the Deform 3D finite element simulation software and the 3D Inverse Heat module, and the surface convection heat transfer coefficient is output every 100°C from 0 to 1100°C.

[0059] Step S4: Establish heating models for titanium alloy workpieces of different thicknesses, compare the calculation results of 1# to 3# in step S3, and take the minimum calculated value 1# among the three as the surface convection heat transfer coefficient of the current heating model. Set the thermal radiation coefficient to 0.7, and complete the temperature field calculation of the workpiece under different heating systems. The heating system is set as follows Figure 5 As shown. In step S4, the titanium alloy workpiece is TA15 titanium alloy. The calculation results of the surface convection heat transfer coefficient are as follows:

[0060] Temperature (℃) 20 100 200 300 400 500 Heat transfer coefficient (N / s / mm / ℃) 0.013 0.014 0.018 0.025 0.036 0.054 Temperature (℃) 600 700 800 900 1000 1100 Heat transfer coefficient (N / s / mm / ℃) 0.068 0.139 0.209 0.235 0.27 0.31

[0061] Step S5: Based on the temperature field calculation results, the preheating, heating, and holding times required for the minimum heat penetration of the workpiece are analyzed, and then the heating system for titanium alloy workpieces of different thicknesses is set, as shown in the following table, and the heating system for the titanium alloy β phase region is finally established. The temperature field calculation results of the workpiece heating process are as follows Figure 6 shown.

[0062] The final minimum temperature of the workpiece center is 1098.1℃, which meets the set conditions.

[0063] Workpiece thickness / mm Preheating time / min Heating time / min Holding time / min 300 90 90 140

[0064] Example 2:

[0065] Step S1: Prepare three square titanium alloy billets, marked as 1# to 3#. The size of the titanium billets is as follows: Figure 1 . Prepare several thermocouples, complete the drilling of the blank at positions ①~⑤, connect the thermocouples to the blank at positions ①~⑤ blind holes, use insulation cotton to seal the gaps between the blind holes and the thermocouple wires, and prepare additional thermocouples to measure the ambient temperature of the blank. In step S1, the titanium alloy material is a common low-cost titanium metal such as TC4. It is stipulated that the length of the square billet is 280mm, the width is 140mm, and the thickness is 140. The drilling depths of ①~⑤ are respectively recorded as M1~M5; wherein L=2W=2D≥280mm, and M1=M4=M5=70mm, M3=35mm, and M2=17.5mm; the thermocouple is an N-type thermocouple with a diameter of 8mm, and the designed drilling diameter is 10mm.

[0066] Step S2: Complete the heating test of 1#~3# titanium alloy billets. The heating method is room temperature furnace heating until the temperature reaches above 1100℃. The heating rate is 5℃ / min. The temperature rise curves of different billets are recorded separately using a patrol meter. The temperature acquisition cycle setting range is 2minn / time. The length of the heating furnace in step S2 is 3000mm and the width is 2000mm. The coordinates of 1#~3# billets are set to (x1, y1), (x2, y2), and (x3, y3), respectively. Among them, (x1, y1) = (0, 0); (x2, y2) (950, 0); (x3, y3) = (0, 1450). That is, place 1#~3# billets in the center, center edge, and center bottom of the heating furnace, respectively. As follows Figure 2 、 Figure 3 shown.

[0067] Step S3: Complete the back calculation of the surface convection heat transfer coefficient at different furnace positions, and repeatedly debug the model until the error between the simulated temperature rise curve value and the measured value is within 5°C, as follows Figure 4In step S3, the surface convection heat transfer coefficient of samples 1# to 3# is calculated using the Deform 3D finite element simulation software and the 3D Inverse Heat module, and the surface convection heat transfer coefficient is output every 100°C from 0 to 1100°C.

[0068] Step S4: Establish heating models for titanium alloy workpieces of different thicknesses, compare the calculation results of 1# to 3# in step S3, and take the minimum calculated value 1# among the three as the surface convection heat transfer coefficient of the current heating model. Set the thermal radiation coefficient to 0.7, and complete the temperature field calculation of the workpiece under different heating systems. The heating system is set as follows Figure 5 As shown. In step S4, the titanium alloy workpiece is TA15 titanium alloy. The calculation results of the surface convection heat transfer coefficient are as follows:

[0069] Temperature (℃) 20 100 200 300 400 500 Heat transfer coefficient (N / s / mm / ℃) 0.013 0.014 0.018 0.025 0.036 0.054 Temperature (℃) 600 700 800 900 1000 1100 Heat transfer coefficient (N / s / mm / ℃) 0.068 0.139 0.209 0.235 0.27 0.31

[0070] Step S5: Based on the temperature field calculation results, the preheating, ramp-up, and holding times required for minimum heat penetration are analyzed. Heating schedules for titanium alloy workpieces of varying thicknesses are then set, as shown in the table below. This completes the heating schedule for the titanium alloy's β-phase region. The final minimum core temperature of the workpiece is 1099.6°C, meeting the set requirements.

[0071] Workpiece thickness / mm Preheating time / min Heating time / min Holding time / min 350 90 100 150

[0072] Example 3:

[0073] Step S1: Prepare three square titanium alloy billets, marked as 1# to 3#. The size of the titanium billets is as follows: Figure 1 . Prepare several thermocouples, complete the drilling of the blank at positions ①~⑤, connect the thermocouples to the blank at positions ①~⑤ blind holes, use insulation cotton to seal the gaps between the blind holes and the thermocouple wires, and prepare additional thermocouples to measure the ambient temperature of the blank. In step S1, the titanium alloy material is a common low-cost titanium metal such as TC4. It is stipulated that the length of the square billet is 280mm, the width is 140mm, and the thickness is 140. The drilling depths of ①~⑤ are respectively recorded as M1~M5; wherein L=2W=2D≥280mm, and M1=M4=M5=70mm, M3=35mm, and M2=17.5mm; the thermocouple is an N-type thermocouple with a diameter of 8mm, and the designed drilling diameter is 10mm.

[0074] Step S2: Complete the heating test of 1#~3# titanium alloy billets. The heating method is room temperature furnace heating until the temperature reaches above 1100℃. The heating rate is 5℃ / min. The temperature rise curves of different billets are recorded separately using a patrol meter. The temperature acquisition cycle setting range is 2minn / time. The length of the heating furnace in step S2 is 3000mm and the width is 2000mm. The coordinates of 1#~3# billets are set to (x1, y1), (x2, y2), and (x3, y3), respectively. Among them, (x1, y1) = (0, 0); (x2, y2) (950, 0); (x3, y3) = (0, 1450). That is, place 1#~3# billets in the center, center edge, and center bottom of the heating furnace, respectively. As follows Figure 2 、 Figure 3 shown.

[0075] Step S3: Complete the back calculation of the surface convection heat transfer coefficient at different furnace positions, and repeatedly debug the model until the error between the simulated temperature rise curve value and the measured value is within 5°C, as follows Figure 4 In step S3, the surface convection heat transfer coefficient of samples 1# to 3# is calculated using the Deform 3D finite element simulation software and the 3D Inverse Heat module, and the surface convection heat transfer coefficient is output every 100°C from 0 to 1100°C.

[0076] Step S4: Establish heating models for titanium alloy workpieces of different thicknesses, compare the calculation results of 1# to 3# in step S3, and take the minimum calculated value 1# among the three as the surface convection heat transfer coefficient of the current heating model. Set the thermal radiation coefficient to 0.7, and complete the temperature field calculation of the workpiece under different heating systems. The heating system is set as follows Figure 5 As shown. In step S4, the titanium alloy workpiece is TA15 titanium alloy. The calculation results of the surface convection heat transfer coefficient are as follows:

[0077] Temperature (℃) 20 100 200 300 400 500 Heat transfer coefficient (N / s / mm / ℃) 0.013 0.014 0.018 0.025 0.036 0.054 Temperature (℃) 600 700 800 900 1000 1100 Heat transfer coefficient (N / s / mm / ℃) 0.068 0.139 0.209 0.235 0.27 0.31

[0078] Step S5: Based on the temperature field calculation results, the preheating, ramp-up, and holding times required for minimum heat penetration are analyzed. Heating schedules for titanium alloy workpieces of varying thicknesses are then set, as shown in the table below. This completes the heating schedule for the titanium alloy's β-phase region. The final minimum core temperature of the workpiece is 1100°C, meeting the set requirements.

[0079] Workpiece thickness / mm Preheating time / min Heating time / min Holding time / min 440 120 120 170

[0080] Example 4:

[0081] Step S1: Prepare three square titanium alloy billets, marked as 1# to 3#. The size of the titanium billets is as follows: Figure 1. Prepare several thermocouples, complete the drilling of the blank at positions ①~⑤, connect the thermocouples to the blank at positions ①~⑤ blind holes, use insulation cotton to seal the gaps between the blind holes and the thermocouple wires, and prepare additional thermocouples to measure the ambient temperature of the blank. In step S1, the titanium alloy material is a common low-cost titanium metal such as TC4. It is stipulated that the length of the square billet is 280mm, the width is 140mm, and the thickness is 140. The drilling depths of ①~⑤ are respectively recorded as M1~M5; wherein L=2W=2D≥280mm, and M1=M4=M5=70mm, M3=35mm, and M2=17.5mm; the thermocouple is an N-type thermocouple with a diameter of 8mm, and the designed drilling diameter is 10mm.

[0082] Step S2: Complete the heating test of 1#~3# titanium alloy billets. The heating method is room temperature furnace heating until the temperature reaches above 1100℃. The heating rate is 5℃ / min. The temperature rise curves of different billets are recorded separately using a patrol meter. The temperature acquisition cycle setting range is 2minn / time. The length of the heating furnace in step S2 is 3000mm and the width is 2000mm. The coordinates of 1#~3# billets are set to (x1, y1), (x2, y2), and (x3, y3), respectively. Among them, (x1, y1) = (0, 0); (x2, y2) (950, 0); (x3, y3) = (0, 1450). That is, place 1#~3# billets in the center, center edge, and center bottom of the heating furnace, respectively. As follows Figure 2 、 Figure 3 shown.

[0083] Step S3: Complete the back calculation of the surface convection heat transfer coefficient at different furnace positions, and repeatedly debug the model until the error between the simulated temperature rise curve value and the measured value is within 5°C, as follows Figure 4 In step S3, the surface convection heat transfer coefficient of samples 1# to 3# is calculated using the Deform 3D finite element simulation software and the 3D Inverse Heat module, and the surface convection heat transfer coefficient is output every 100°C from 0 to 1100°C.

[0084] Step S4: Establish heating models for titanium alloy workpieces of different thicknesses, compare the calculation results of 1# to 3# in step S3, and take the minimum calculated value 1# among the three as the surface convection heat transfer coefficient of the current heating model. Set the thermal radiation coefficient to 0.7, and complete the temperature field calculation of the workpiece under different heating systems. The heating system is set as follows Figure 5 As shown. In step S4, the titanium alloy workpiece is TA15 titanium alloy. The calculation results of the surface convection heat transfer coefficient are as follows:

[0085] Temperature (℃) 20 100 200 300 400 500 Heat transfer coefficient (N / s / mm / ℃) 0.013 0.014 0.018 0.025 0.036 0.054 Temperature (℃) 600 700 800 900 1000 1100 Heat transfer coefficient (N / s / mm / ℃) 0.068 0.139 0.209 0.235 0.27 0.31

[0086] Step S5: Based on the temperature field calculation results, the preheating, ramp-up, and holding times required for minimum heat penetration are analyzed. Heating schedules for titanium alloy workpieces of varying thicknesses are then set, as shown in the table below. This completes the heating schedule for the titanium alloy's β-phase region. The final minimum core temperature of the workpiece is 1098.5°C, meeting the specified requirements.

[0087] Workpiece thickness / mm Preheating time / min Heating time / min Holding time / min 550 120 130 180

[0088] Example 5:

[0089] Step S1: Prepare three square titanium alloy billets, marked as 1# to 3#. The size of the titanium billets is as follows: Figure 1 . Prepare several thermocouples, complete the drilling of the blank at positions ①~⑤, connect the thermocouples to the blank at positions ①~⑤ blind holes, use insulation cotton to seal the gaps between the blind holes and the thermocouple wires, and prepare additional thermocouples to measure the ambient temperature of the blank. In step S1, the titanium alloy material is a common low-cost titanium metal such as TC4. It is stipulated that the length of the square billet is 280mm, the width is 140mm, and the thickness is 140. The drilling depths of ①~⑤ are respectively recorded as M1~M5; wherein L=2W=2D≥280mm, and M1=M4=M5=70mm, M3=35mm, and M2=17.5mm; the thermocouple is an N-type thermocouple with a diameter of 8mm, and the designed drilling diameter is 10mm.

[0090] Step S2: Complete the heating test of 1#~3# titanium alloy billets. The heating method is room temperature furnace heating until the temperature reaches above 1100℃. The heating rate is 5℃ / min. The temperature rise curves of different billets are recorded separately using a patrol meter. The temperature acquisition cycle setting range is 2minn / time. The length of the heating furnace in step S2 is 3000mm and the width is 2000mm. The coordinates of 1#~3# billets are set to (x1, y1), (x2, y2), and (x3, y3), respectively. Among them, (x1, y1) = (0, 0); (x2, y2) (950, 0); (x3, y3) = (0, 1450). That is, place 1#~3# billets in the center, center edge, and center bottom of the heating furnace, respectively. As follows Figure 2 、 Figure 3 shown.

[0091] Step S3: Complete the back calculation of the surface convection heat transfer coefficient at different furnace positions, and repeatedly debug the model until the error between the simulated temperature rise curve value and the measured value is within 5°C, as follows Figure 4 In step S3, the surface convection heat transfer coefficient of samples 1# to 3# is calculated using the Deform 3D finite element simulation software and the 3D Inverse Heat module, and the surface convection heat transfer coefficient is output every 100°C from 0 to 1100°C.

[0092] Step S4: Establish heating models for titanium alloy workpieces of different thicknesses, compare the calculation results of 1# to 3# in step S3, and take the minimum calculated value 1# among the three as the surface convection heat transfer coefficient of the current heating model. Set the thermal radiation coefficient to 0.7, and complete the temperature field calculation of the workpiece under different heating systems. The heating system is set as follows Figure 5 As shown. In step S4, the titanium alloy workpiece is TA15 titanium alloy. The calculation results of the surface convection heat transfer coefficient are as follows:

[0093] Temperature (℃) 20 100 200 300 400 500 Heat transfer coefficient (N / s / mm / ℃) 0.013 0.014 0.018 0.025 0.036 0.054 Temperature (℃) 600 700 800 900 1000 1100 Heat transfer coefficient (N / s / mm / ℃) 0.068 0.139 0.209 0.235 0.27 0.31

[0094] Step S5: Based on the temperature field calculation results, the preheating, ramp-up, and holding times required for minimum heat penetration are analyzed. Heating schedules for titanium alloy workpieces of varying thicknesses are then set, as shown in the table below. This completes the heating schedule for the titanium alloy's β-phase region. The final minimum core temperature of the workpiece is 1100°C, meeting the set requirements.

[0095] Workpiece thickness / mm Preheating time / min Heating time / min Holding time / min 650 150 160 220

[0096] Example 6:

[0097] Step S1: Prepare three square titanium alloy billets, marked as 1# to 3#. The size of the titanium billets is as follows: Figure 1 . Prepare several thermocouples, complete the drilling of the blank at positions ①~⑤, connect the thermocouples to the blank at positions ①~⑤ blind holes, use insulation cotton to seal the gaps between the blind holes and the thermocouple wires, and prepare additional thermocouples to measure the ambient temperature of the blank. In step S1, the titanium alloy material is a common low-cost titanium metal such as TC4. It is stipulated that the length of the square billet is 280mm, the width is 140mm, and the thickness is 140. The drilling depths of ①~⑤ are respectively recorded as M1~M5; wherein L=2W=2D≥280mm, and M1=M4=M5=70mm, M3=35mm, and M2=17.5mm; the thermocouple is an N-type thermocouple with a diameter of 8mm, and the designed drilling diameter is 10mm.

[0098] Step S2: Complete the heating test of 1#~3# titanium alloy billets. The heating method is room temperature furnace heating until the temperature reaches above 1100℃. The heating rate is 5℃ / min. The temperature rise curves of different billets are recorded separately using a patrol meter. The temperature acquisition cycle setting range is 2minn / time. The length of the heating furnace in step S2 is 3000mm and the width is 2000mm. The coordinates of 1#~3# billets are set to (x1, y1), (x2, y2), and (x3, y3), respectively. Among them, (x1, y1) = (0, 0); (x2, y2) (950, 0); (x3, y3) = (0, 1450). That is, place 1#~3# billets in the center, center edge, and center bottom of the heating furnace, respectively. As follows Figure 2 、 Figure 3 shown.

[0099] Step S3: Complete the back calculation of the surface convection heat transfer coefficient at different furnace positions, and repeatedly debug the model until the error between the simulated temperature rise curve value and the measured value is within 5°C, as follows Figure 4 In step S3, the surface convection heat transfer coefficient of samples 1# to 3# is calculated using the Deform 3D finite element simulation software and the 3D Inverse Heat module, and the surface convection heat transfer coefficient is output every 100°C from 0 to 1100°C.

[0100] Step S4: Establish heating models for titanium alloy workpieces of different thicknesses, compare the calculation results of 1# to 3# in step S3, and take the minimum calculated value 1# among the three as the surface convection heat transfer coefficient of the current heating model. Set the thermal radiation coefficient to 0.7, and complete the temperature field calculation of the workpiece under different heating systems. The heating system is set as follows Figure 5 As shown. In step S4, the titanium alloy workpiece is TA15 titanium alloy. The calculation results of the surface convection heat transfer coefficient are as follows:

[0101] Temperature (℃) 20 100 200 300 400 500 Heat transfer coefficient (N / s / mm / ℃) 0.013 0.014 0.018 0.025 0.036 0.054 Temperature (℃) 600 700 800 900 1000 1100 Heat transfer coefficient (N / s / mm / ℃) 0.068 0.139 0.209 0.235 0.27 0.31

[0102] Step S5: Based on the temperature field calculation results, the preheating, ramp-up, and holding times required for minimum heat penetration are analyzed. Heating schedules for titanium alloy workpieces of varying thicknesses are then set, as shown in the table below. This completes the titanium alloy β-phase heating schedule. The final minimum core temperature is 1098.8°C, meeting the specified requirements.

[0103] Workpiece thickness / mm Preheating time / min Heating time / min Holding time / min 800 180 200 260

[0104] The heating system of the above embodiment is:

[0105]

[0106] Matters not described in detail in this invention are all known technologies.

[0107] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A titanium alloy β-phase region heating method based on finite element simulation, characterized by: The method comprises the following steps: Step S1: Prepare three square titanium alloy billets, labeled 1#-3#, and prepare several thermocouples; mark drilling positions ①-⑤ on the surface of each billet, where ① is the center of 1 / 4 width from one long side, ② is the center of 1 / 4 length from one wide side, ③ is the center of 1 / 4 length from ②, and ④ is the center of the billet; ⑤ is the center of 1 / 4 width from the other long side; complete drilling at positions ①-⑤ of each billet, and connect the thermocouples one by one to the bottom of the blind hole positions ①-⑤ of the billet; Step S2: Complete the heating test of 1#-3# titanium alloy billets by heating at room temperature in a furnace until the temperature reaches above 1100°C, with a heating rate of 4-8°C / min. Use a patrol meter to record the temperature rise curves of different billets respectively, and set the temperature collection cycle range from 2min to 10min / time; Step S3: Complete the back calculation of the surface convection heat transfer coefficient at different positions of the furnace, and repeatedly debug the model until the error between the simulated temperature rise curve value and the measured value is within 5°C; Step S4: Establish heating models for titanium alloy workpieces of different thicknesses, compare the calculation results of 1#-3# in step S3, and take the minimum calculated value among the three as the surface convection heat transfer coefficient of the current heating model; set the thermal radiation coefficient to 0.6-0.8, and complete the temperature field calculation of the titanium alloy workpiece under different heating systems; Step S5: Based on the temperature field calculation results, the preheating, heating, and holding times required for the minimum heat penetration of the titanium alloy workpiece are analyzed, and then the heating system for titanium alloy workpieces of different thicknesses is set. The minimum temperature of the core of the billet is greater than or equal to the heating temperature -3°C, and finally the heating system for the titanium alloy β phase region is formulated.

2. The method for heating the titanium alloy β phase region based on finite element simulation according to claim 1, characterized in that: In step S1, the length of the square blank is L, the width is W, and the thickness is D, and the punching depths of ①-⑤ are respectively recorded as M1-M5; wherein L=2W=2D≥280mm, and M1=M4=M5=0.5D, M3=0.25D, and M2=0.125D.

3. The method for heating the titanium alloy β phase region based on finite element simulation according to claim 1, characterized in that: In step S1, the thermocouple is an N-type thermocouple with a diameter of 6-8 mm, and the designed drilling diameter is 8-10 mm.

4. The method for heating the titanium alloy β phase region based on finite element simulation according to claim 1, characterized in that: In step S1, the blind hole and the gap between the thermocouple wires are sealed with thermal insulation cotton, and a thermocouple is additionally prepared to measure the ambient temperature of the blank.

5. The method for heating the titanium alloy β phase region based on finite element simulation according to claim 1, characterized in that: In step S2, the length of the heating furnace is A mm and the width is B mm; the coordinates of the 1#-3# billets are set to (x1, y1), (x2, y2), and (x3, y3), respectively; among which (x1, y1) = (0, 0); (x2, y2) = [(B / 2)-50, 0]; (x3, y3) = [0, (A / 2)-50].

6. The method for heating the titanium alloy β phase region based on finite element simulation according to claim 1, characterized in that: In step S3, the surface convection heat transfer coefficient of samples 1#-3# is calculated using the Deform 3D finite element simulation software and the 3D Inverse Heat module. The surface convection heat transfer coefficient is output every 100°C from 0 to 1100°C, and the calculated value is within the range of 0.01-0.4N / s / mm / °C.

7. The method for heating the titanium alloy β phase region based on finite element simulation according to claim 1, characterized in that: In step S4, the titanium alloy workpiece is of α-type or (α+β)-type titanium alloy.

8. The method for heating the titanium alloy β phase region based on finite element simulation according to claim 1, characterized in that: In step S5, the heating system for titanium alloy workpieces of different thicknesses is as follows: When the workpiece thickness is 200-400mm, the preheating time is 80-100min, the heating time is 90-120min, and the holding time is 120-180min; When the workpiece thickness is 400-600mm, the preheating time is 110-130min, the heating time is 120-150min, and the holding time is 150-180min; When the workpiece thickness is 600-750mm, the preheating time is 140-160min, the heating time is 150-180min, and the holding time is 180-240min; When the workpiece thickness is 750-900mm, the preheating time is 170-190min, the heating time is 180-240min, and the holding time is 240-300min.

9. The method for heating the titanium alloy β phase region based on finite element simulation according to claim 8, characterized in that: In step S5, the charging temperature of the heating system is 800° C.-850° C., the heating temperature is 50-150° C. above the phase transition point temperature of the titanium alloy, and the workpiece thickness is the thickness dimension of the workpiece at the maximum cross-sectional area.

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