大型异形环件多步辗扩数值模拟研究
发布时间：2018-11-01 21:21
【摘要】：大型环形零件是海上风力发电、航空航天、海洋船舶的制造及电力、石油、工程机械等方面广泛应用的关键零件。环件辗扩新技术已经能够很好的辗扩生产矩形截面环件,它具有省力、节能、节材、生产效率高、生产成本低等显著特点。在实际异形环件辗扩过程中,辗扩过程不稳定,辗扩环件的尺寸精度低和微观组织及力学性能控制难度大,辗扩力较大,易导致模具损坏,这在一定程度上限制了异形环件辗扩工艺在工程中的应用。要解决上述问题必须研究和掌握辗扩过程中金属的流动规律,选择合理的辗扩模具以及合理的芯辊进给策略及轧辊运动控制方法。本文利用数值模拟的方法,对一种既有外凹槽又有内台阶的大型非矩形截面的环件进行了热力耦合模拟分析。通过Gleeble-3500实验机建立了Q345E钢的流变应力模型,针对成形产品复杂的轮廓特点,采用多步辗扩,并对每步辗扩多次改进辗扩用毛坯,设计出两套合理的模具,推导了辗扩过程中轧辊的运动控制方程,确定了辗扩过程中环件的塑性锻透条件和咬入条件,获得了轧辊转速和芯辊进给速度的合理取值范围。在此基础上,分别建立了内台阶双件辗扩和带有内台阶的外凹槽环件热辗扩过程的有限元数值模拟模型,分别获得了两种环件热辗扩环件等效应变及温度随辗扩时间的变化规律,系统的研究了不同锻坯加热温度、驱动辊转速、芯辊进给速度等工艺参数对环件辗扩过程的等效应变和温度分布、径向辗扩力和力矩的影响规律,优化第二步外凹槽辗扩工艺参数,确定了一种可运用于实际生产的有限元模型。数值模拟研究表明,利用所建立的模型可以实现异形环件多步辗扩的生产。其中在预热温度1250℃、芯辊速率0.8mm/s、1mm/s、驱动辊转速30.6r/min辗扩时环件的最大应变出现在外径的棱角处和内径上下两个端面,环件塑性变形区由这些部位向环件的其它部位扩展,内台阶轮廓在100s左右完全充满,充满状况较好,前100s环件发生局部变形,直径长大不明显,直径长大主要发生在100s以后的辗扩阶段;辗扩外凹槽时芯辊进给速率分别为1.2mm/s、0.8mm/s、0.3mm/s逐级减速,驱动辊转速7.644r/min参数下,环件的外凹槽在85s左右充满,整个环件的塑性变形是由外凹槽部位与环件内径小半径的台阶部位向环件的其它部位扩展的,等效应变的最大值在外凹槽部位与台阶部位。
[Abstract]:Large annular parts are the key parts of offshore wind power generation, aerospace, marine ship manufacture, electric power, petroleum, construction machinery and so on. The new ring rolling technology has been able to produce rectangular section ring, which is characterized by saving labor, saving energy, saving materials, high production efficiency, low production cost and so on. In the process of rolling, the rolling process is unstable, the dimension precision of ring rolling is low, the control of microstructure and mechanical properties is difficult, and the rolling force is large, which can easily lead to die damage. To a certain extent, the application of ring rolling technology in engineering is limited. In order to solve the above problems, it is necessary to study and master the rule of metal flow in the rolling process, select reasonable rolling die, reasonable feeding strategy of core roll and control method of roll motion. In this paper, the thermodynamic coupling analysis of a large non-rectangular ring with both external grooves and inner steps is carried out by means of numerical simulation. The flow stress model of Q345E steel was established by Gleeble-3500 test machine. In view of the complex profile characteristics of the forming products, multi-step rolling was adopted, and two sets of reasonable dies were designed for improving the blanks for rolling several times in each step of rolling. The control equation of roll motion during rolling process is derived, the plastic forging penetration condition and biting condition of ring during rolling process are determined, and the reasonable range of roll speed and feed speed of core roll is obtained. On this basis, the finite element numerical simulation models of the hot rolling process of the inner step double-piece ring and the outer groove ring with inner step are established, respectively. The changes of equivalent strain and temperature with rolling time of two kinds of hot rolling ring were obtained, and the heating temperature of different forging billet and the rotation speed of driving roll were studied systematically. The influence of process parameters such as feed speed of core-roller on equivalent strain and temperature distribution, radial rolling force and moment of ring rolling process is studied, and the technological parameters of second step external groove rolling are optimized. A finite element model which can be used in practical production is determined. The numerical simulation results show that the multi-step ring rolling can be realized by using the established model. When the preheating temperature is 1250 鈩，
本文编号：2305131
[Abstract]:Large annular parts are the key parts of offshore wind power generation, aerospace, marine ship manufacture, electric power, petroleum, construction machinery and so on. The new ring rolling technology has been able to produce rectangular section ring, which is characterized by saving labor, saving energy, saving materials, high production efficiency, low production cost and so on. In the process of rolling, the rolling process is unstable, the dimension precision of ring rolling is low, the control of microstructure and mechanical properties is difficult, and the rolling force is large, which can easily lead to die damage. To a certain extent, the application of ring rolling technology in engineering is limited. In order to solve the above problems, it is necessary to study and master the rule of metal flow in the rolling process, select reasonable rolling die, reasonable feeding strategy of core roll and control method of roll motion. In this paper, the thermodynamic coupling analysis of a large non-rectangular ring with both external grooves and inner steps is carried out by means of numerical simulation. The flow stress model of Q345E steel was established by Gleeble-3500 test machine. In view of the complex profile characteristics of the forming products, multi-step rolling was adopted, and two sets of reasonable dies were designed for improving the blanks for rolling several times in each step of rolling. The control equation of roll motion during rolling process is derived, the plastic forging penetration condition and biting condition of ring during rolling process are determined, and the reasonable range of roll speed and feed speed of core roll is obtained. On this basis, the finite element numerical simulation models of the hot rolling process of the inner step double-piece ring and the outer groove ring with inner step are established, respectively. The changes of equivalent strain and temperature with rolling time of two kinds of hot rolling ring were obtained, and the heating temperature of different forging billet and the rotation speed of driving roll were studied systematically. The influence of process parameters such as feed speed of core-roller on equivalent strain and temperature distribution, radial rolling force and moment of ring rolling process is studied, and the technological parameters of second step external groove rolling are optimized. A finite element model which can be used in practical production is determined. The numerical simulation results show that the multi-step ring rolling can be realized by using the established model. When the preheating temperature is 1250 鈩，
本文编号：2305131
本文链接：https://www.wllwen.com/kejilunwen/jiagonggongyi/2305131.html
