TA15钛合金径轴向环轧全过程变形与组织演变
发布时间：2018-07-18 15:26
【摘要】：环件径轴向辗轧是制造高性能钛合金环件的先进成形技术,在航空、航天等领域得到了广泛的应用。为满足钛合金环件的高性能要求,需要同时获得满足精度要求的环件形状和满足使用要求的组织性能,即要实现钛合金环件的成形成性一体化制造。然而,钛合金环件径轴向辗轧是多模具、多参数、多场耦合作用下的复杂动态时变成形过程,并且该过程通常包含加热、转移、辗轧、冷却等复杂的温度和变形历程,使得钛合金环件成形和组织控制成为具有挑战性的难题。为此,本文采用有限元数值模拟、实验研究和理论分析相结合的方法,对TA15钛合金环件径轴向辗轧变形和组织演变进行了系统深入的研究,主要研究内容及结果如下:实验获得了TA15钛合金热变形全过程的组织演变规律,并分别建立了相应过程的组织演变模型。在温降过程,初生等轴α相长大速率随温降速度的增大而增大,但在相同的温降范围内,低的温降速度会导致较长的冷却时间,生成的初生等轴α相体积分数和晶粒尺寸较大。在温升过程,初生等轴α相溶解速率随温升速度的增大而增大,而在相同的温升范围内,低的温升速度会导致较长的温升时间,最终的初生等轴α相体积分数和晶粒尺寸较小。在压缩变形过程,随应变速率的增大,初生等轴α相晶粒细化程度有所增大,而初生等轴α相体积分数主要由变形温度决定,变形过程对初生等轴α相体积分数的影响较小。确定了环件径轴向辗轧中导向辊、芯辊和锥辊的运动与环件实时外径、高度和厚度的关联关系,进而建立了多轧辊运动控制模型。基于ABAQUS有限元软件,通过VUAMP子程序开发引入多轧辊运动控制模型,并设置虚拟传感器在线实时检测环件外径、高度和厚度,同时通过VUSDFLD和USDFLD子程序开发引入加热、转移、辗轧和冷却阶段的TA15钛合金组织演变模型,实现了多轧辊反馈控制下钛合金环件径轴向辗轧全过程宏微观有限元建模与仿真。并从宏观变形和微观组织两方面实验验证了有限元模型可靠性。探明了环坯轧比Ψ和轴径向变形量比k对TA15环件变形和组织演变的影响规律。结果表明,Ψ较大同时k较小时,圆度误差较大,而其他条件下的圆度都较好;随Ψ增大,高度误差和厚度误差都增大,初生等轴α相晶粒尺寸分布均匀性变差,而初生等轴α相体积分数分布均匀性先变好后变差;随k增大,高度误差减小而厚度误差增大;Ψ较大时,随k增大,初生等轴α相体积分数和晶粒尺寸分布均匀性都先变好后变差;Ψ较小时,随k增大,初生等轴α相晶粒尺寸分布均匀性变差而体积分数分布均匀性变好。综合考虑环件的圆度、截面质量和组织,本文研究条件下确定的优选环坯为:Ψ约为1.7,k为0.3-0.7。基于优选环坯,揭示了环坯加热温度T_0、直径增长速度V_D、轧制速度V_1对TA15环件变形和组织演变的影响规律。结果表明,不同工艺条件下的环件圆度和高度误差都较小,减小V_D和增大V_1能减小厚度误差;T_0决定了初生等轴α相体积分数;提高V_D能改善初生等轴α相晶粒尺寸和体积分数的分布均匀性;增大V_1能改善初生等轴α相体积分数的分布均匀性,但使晶粒尺寸分布均匀性变差。综合考虑环件的圆度、截面质量和组织,确定优选工艺参数组合为:T_0约为相变点以下25℃,保证环件稳定性和不超过设备力能极限的前提下,尽量增大V_D和V_1,本文研究条件下优选的V_D和V_1分别约为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.
【学位授予单位】：西北工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TG339
本文编号：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.
【学位授予单位】：西北工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TG339
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相关博士学位论文 前1条
1 潘利波;环件径轴向轧制变形规律与CAPP系统研究[D];武汉理工大学;2007年
相关硕士学位论文 前1条
1 万自永;难变形材料环件轧制过程的三维有限元数值模拟[D];西北工业大学;2007年
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