TA15鈦合金徑軸向環(huán)軋全過程變形與組織演變
發(fā)布時間：2018-07-18 15:26
【摘要】：環(huán)件徑軸向輾軋是制造高性能鈦合金環(huán)件的先進(jìn)成形技術(shù),在航空、航天等領(lǐng)域得到了廣泛的應(yīng)用。為滿足鈦合金環(huán)件的高性能要求,需要同時獲得滿足精度要求的環(huán)件形狀和滿足使用要求的組織性能,即要實(shí)現(xiàn)鈦合金環(huán)件的成形成性一體化制造。然而,鈦合金環(huán)件徑軸向輾軋是多模具、多參數(shù)、多場耦合作用下的復(fù)雜動態(tài)時變成形過程,并且該過程通常包含加熱、轉(zhuǎn)移、輾軋、冷卻等復(fù)雜的溫度和變形歷程,使得鈦合金環(huán)件成形和組織控制成為具有挑戰(zhàn)性的難題。為此,本文采用有限元數(shù)值模擬、實(shí)驗(yàn)研究和理論分析相結(jié)合的方法,對TA15鈦合金環(huán)件徑軸向輾軋變形和組織演變進(jìn)行了系統(tǒng)深入的研究,主要研究內(nèi)容及結(jié)果如下:實(shí)驗(yàn)獲得了TA15鈦合金熱變形全過程的組織演變規(guī)律,并分別建立了相應(yīng)過程的組織演變模型。在溫降過程,初生等軸α相長大速率隨溫降速度的增大而增大,但在相同的溫降范圍內(nèi),低的溫降速度會導(dǎo)致較長的冷卻時間,生成的初生等軸α相體積分?jǐn)?shù)和晶粒尺寸較大。在溫升過程,初生等軸α相溶解速率隨溫升速度的增大而增大,而在相同的溫升范圍內(nèi),低的溫升速度會導(dǎo)致較長的溫升時間,最終的初生等軸α相體積分?jǐn)?shù)和晶粒尺寸較小。在壓縮變形過程,隨應(yīng)變速率的增大,初生等軸α相晶粒細(xì)化程度有所增大,而初生等軸α相體積分?jǐn)?shù)主要由變形溫度決定,變形過程對初生等軸α相體積分?jǐn)?shù)的影響較小。確定了環(huán)件徑軸向輾軋中導(dǎo)向輥、芯輥和錐輥的運(yùn)動與環(huán)件實(shí)時外徑、高度和厚度的關(guān)聯(lián)關(guān)系,進(jìn)而建立了多軋輥運(yùn)動控制模型�；贏BAQUS有限元軟件,通過VUAMP子程序開發(fā)引入多軋輥運(yùn)動控制模型,并設(shè)置虛擬傳感器在線實(shí)時檢測環(huán)件外徑、高度和厚度,同時通過VUSDFLD和USDFLD子程序開發(fā)引入加熱、轉(zhuǎn)移、輾軋和冷卻階段的TA15鈦合金組織演變模型,實(shí)現(xiàn)了多軋輥反饋控制下鈦合金環(huán)件徑軸向輾軋全過程宏微觀有限元建模與仿真。并從宏觀變形和微觀組織兩方面實(shí)驗(yàn)驗(yàn)證了有限元模型可靠性。探明了環(huán)坯軋比Ψ和軸徑向變形量比k對TA15環(huán)件變形和組織演變的影響規(guī)律。結(jié)果表明,Ψ較大同時k較小時,圓度誤差較大,而其他條件下的圓度都較好;隨Ψ增大,高度誤差和厚度誤差都增大,初生等軸α相晶粒尺寸分布均勻性變差,而初生等軸α相體積分?jǐn)?shù)分布均勻性先變好后變差;隨k增大,高度誤差減小而厚度誤差增大;Ψ較大時,隨k增大,初生等軸α相體積分?jǐn)?shù)和晶粒尺寸分布均勻性都先變好后變差;Ψ較小時,隨k增大,初生等軸α相晶粒尺寸分布均勻性變差而體積分?jǐn)?shù)分布均勻性變好。綜合考慮環(huán)件的圓度、截面質(zhì)量和組織,本文研究條件下確定的優(yōu)選環(huán)坯為:Ψ約為1.7,k為0.3-0.7�；趦�(yōu)選環(huán)坯,揭示了環(huán)坯加熱溫度T_0、直徑增長速度V_D、軋制速度V_1對TA15環(huán)件變形和組織演變的影響規(guī)律。結(jié)果表明,不同工藝條件下的環(huán)件圓度和高度誤差都較小,減小V_D和增大V_1能減小厚度誤差;T_0決定了初生等軸α相體積分?jǐn)?shù);提高V_D能改善初生等軸α相晶粒尺寸和體積分?jǐn)?shù)的分布均勻性;增大V_1能改善初生等軸α相體積分?jǐn)?shù)的分布均勻性,但使晶粒尺寸分布均勻性變差。綜合考慮環(huán)件的圓度、截面質(zhì)量和組織,確定優(yōu)選工藝參數(shù)組合為:T_0約為相變點(diǎn)以下25℃,保證環(huán)件穩(wěn)定性和不超過設(shè)備力能極限的前提下,盡量增大V_D和V_1,本文研究條件下優(yōu)選的V_D和V_1分別約為40mm/s和1.38m/s。
[Abstract]:Axial ring rolling is an advanced forming technology for manufacturing high performance titanium alloy ring parts. It has been widely used in aerospace and aerospace fields. In order to meet the high performance requirements of titanium alloy rings, it is necessary to obtain the shape of the ring parts which meet the requirements of precision and meet the requirements of the use of the fabric. That is to realize the forming of the titanium alloy ring. However, the axial rolling of the titanium alloy ring is the process of forming the complex dynamic time of multi die, multi parameter and multi field coupling, and the process usually contains complex temperature and deformation processes such as heating, transfer, rolling and cooling, making the forming and microstructure control of the titanium alloy ring a challenging problem. In this paper, the finite element numerical simulation, the experimental study and the theoretical analysis are combined to study the axial rolling deformation and microstructure evolution of the TA15 titanium alloy ring. The main contents and results are as follows: the experiment has obtained the microstructure evolution law of the full range of hot deformation of the TA15 titanium alloy, and established the corresponding over. In the process of temperature drop, the growth rate of primary ISO axis alpha phase increases with the increase of temperature drop, but in the same temperature drop range, the low temperature drop speed will lead to a longer cooling time, and the initial equiaxed alpha phase volume fraction and grain size are larger. In the process of temperature rise, the initial ISO axis alpha dissolution rate increases with the temperature rise. In the same temperature rise range, the low temperature rise speed will lead to a longer temperature rise time, and the final initial equiaxial alpha phase volume fraction and grain size are smaller. In the compression deformation process, the grain refinement range of primary iso - axial alpha phase increases with the increase of the strain rate, but the primary iso - axial alpha phase volume fraction is mainly in the compression deformation process. It is determined by the deformation temperature that the deformation process has little effect on the volume fraction of the primary equiaxed alpha phase. The relationship between the motion of the guide roll, the core roll and the cone roll, the real time outer diameter of the ring, the height and the thickness of the ring is determined, and the motion control model of the multi roll is established. Based on the ABAQUS finite element software, the VUAMP subprogram is developed. The multi roll motion control model was introduced and the virtual sensor was set up to detect the outer diameter, height and thickness of the ring in real time. At the same time, the microstructure evolution model of TA15 titanium alloy was introduced into the stage of heating, transfer, rolling and cooling by VUSDFLD and USDFLD subroutines, and the whole process macro of the axial rolling of titanium alloy ring was realized under the feedback control of multi roll. Micro finite element modeling and simulation are used to verify the reliability of the finite element model from two aspects of macroscopic deformation and microstructure. The effect of K on the deformation and microstructure evolution of TA15 ring is explored. The results show that the roundness error is larger when the K is larger than the size, and the roundness under other conditions is all round. The height error and thickness error increased with the increase, and the uniformity of the grain size distribution of the primary iso - axis alpha phase became worse, while the uniformity of the primary iso - axial alpha phase distribution became better and then changed. With the increase of K, the height error decreased and the thickness error increased; the initial equiaxial alpha phase volume fraction and grain size distribution increased with the increase of K. With the increase of K, the uniformity of the grain size distribution of the primary equiaxed grain size distribution and the uniformity of the distribution of the volume fraction become better with the increase of the uniformity of the grain size distribution of the initial equiaxed alpha phase. The optimum ring billet determined under the condition of this study is about 1.7, and K is 0.3-0.7. based on the preferred ring billet, and the ring billet is revealed. The effect of heat temperature T_0, diameter growth rate V_D and rolling speed V_1 on the deformation and microstructure evolution of TA15 ring parts. The results show that the roundness and height error of ring parts under different technological conditions are smaller, reducing V_D and increasing V_1 can reduce the thickness error; T_0 determines the initial equiaxial alpha phase volume fraction, and V_D can improve the primary equiaxial alpha phase crystal. The distribution uniformity of the particle size and volume fraction can be improved by increasing V_1, but the uniformity of the volume fraction of the initial equiaxed alpha phase can be improved, but the uniformity of the grain size distribution becomes worse. Considering the roundness, the mass and the structure of the ring, the optimum combination of the technological parameters is determined as follows: the T_0 is about 25 degrees below the phase change point, and the stability of the ring is guaranteed and the set is not exceeded. On the premise of the limit of reserve force, V_D and V_1 are increased as far as possible. The optimum V_D and V_1 are about 40mm/s and 1.38m/s. respectively.
【學(xué)位授予單位】：西北工業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：TG339
本文編號：2132331
[Abstract]:Axial ring rolling is an advanced forming technology for manufacturing high performance titanium alloy ring parts. It has been widely used in aerospace and aerospace fields. In order to meet the high performance requirements of titanium alloy rings, it is necessary to obtain the shape of the ring parts which meet the requirements of precision and meet the requirements of the use of the fabric. That is to realize the forming of the titanium alloy ring. However, the axial rolling of the titanium alloy ring is the process of forming the complex dynamic time of multi die, multi parameter and multi field coupling, and the process usually contains complex temperature and deformation processes such as heating, transfer, rolling and cooling, making the forming and microstructure control of the titanium alloy ring a challenging problem. In this paper, the finite element numerical simulation, the experimental study and the theoretical analysis are combined to study the axial rolling deformation and microstructure evolution of the TA15 titanium alloy ring. The main contents and results are as follows: the experiment has obtained the microstructure evolution law of the full range of hot deformation of the TA15 titanium alloy, and established the corresponding over. In the process of temperature drop, the growth rate of primary ISO axis alpha phase increases with the increase of temperature drop, but in the same temperature drop range, the low temperature drop speed will lead to a longer cooling time, and the initial equiaxed alpha phase volume fraction and grain size are larger. In the process of temperature rise, the initial ISO axis alpha dissolution rate increases with the temperature rise. In the same temperature rise range, the low temperature rise speed will lead to a longer temperature rise time, and the final initial equiaxial alpha phase volume fraction and grain size are smaller. In the compression deformation process, the grain refinement range of primary iso - axial alpha phase increases with the increase of the strain rate, but the primary iso - axial alpha phase volume fraction is mainly in the compression deformation process. It is determined by the deformation temperature that the deformation process has little effect on the volume fraction of the primary equiaxed alpha phase. The relationship between the motion of the guide roll, the core roll and the cone roll, the real time outer diameter of the ring, the height and the thickness of the ring is determined, and the motion control model of the multi roll is established. Based on the ABAQUS finite element software, the VUAMP subprogram is developed. The multi roll motion control model was introduced and the virtual sensor was set up to detect the outer diameter, height and thickness of the ring in real time. At the same time, the microstructure evolution model of TA15 titanium alloy was introduced into the stage of heating, transfer, rolling and cooling by VUSDFLD and USDFLD subroutines, and the whole process macro of the axial rolling of titanium alloy ring was realized under the feedback control of multi roll. Micro finite element modeling and simulation are used to verify the reliability of the finite element model from two aspects of macroscopic deformation and microstructure. The effect of K on the deformation and microstructure evolution of TA15 ring is explored. The results show that the roundness error is larger when the K is larger than the size, and the roundness under other conditions is all round. The height error and thickness error increased with the increase, and the uniformity of the grain size distribution of the primary iso - axis alpha phase became worse, while the uniformity of the primary iso - axial alpha phase distribution became better and then changed. With the increase of K, the height error decreased and the thickness error increased; the initial equiaxial alpha phase volume fraction and grain size distribution increased with the increase of K. With the increase of K, the uniformity of the grain size distribution of the primary equiaxed grain size distribution and the uniformity of the distribution of the volume fraction become better with the increase of the uniformity of the grain size distribution of the initial equiaxed alpha phase. The optimum ring billet determined under the condition of this study is about 1.7, and K is 0.3-0.7. based on the preferred ring billet, and the ring billet is revealed. The effect of heat temperature T_0, diameter growth rate V_D and rolling speed V_1 on the deformation and microstructure evolution of TA15 ring parts. The results show that the roundness and height error of ring parts under different technological conditions are smaller, reducing V_D and increasing V_1 can reduce the thickness error; T_0 determines the initial equiaxial alpha phase volume fraction, and V_D can improve the primary equiaxial alpha phase crystal. The distribution uniformity of the particle size and volume fraction can be improved by increasing V_1, but the uniformity of the volume fraction of the initial equiaxed alpha phase can be improved, but the uniformity of the grain size distribution becomes worse. Considering the roundness, the mass and the structure of the ring, the optimum combination of the technological parameters is determined as follows: the T_0 is about 25 degrees below the phase change point, and the stability of the ring is guaranteed and the set is not exceeded. On the premise of the limit of reserve force, V_D and V_1 are increased as far as possible. The optimum V_D and V_1 are about 40mm/s and 1.38m/s. respectively.
【學(xué)位授予單位】：西北工業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：TG339
【參考文獻(xiàn)】
相關(guān)博士學(xué)位論文 前1條
1 潘利波;環(huán)件徑軸向軋制變形規(guī)律與CAPP系統(tǒng)研究[D];武漢理工大學(xué);2007年
相關(guān)碩士學(xué)位論文 前1條
1 萬自永;難變形材料環(huán)件軋制過程的三維有限元數(shù)值模擬[D];西北工業(yè)大學(xué);2007年
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