钛合金管材复合辊型矫直机辊型曲线及仿真研究

发布时间：2018-04-08 16:35

本文选题：钛合金管材　切入点：金属强化　出处：《燕山大学》2015年硕士论文

【摘要】：随着钛合金管材在航空、航天和船舶领域的广泛应用,对其需求量和质量要求越来越高,矫直是钛合金管材生产中的关键工序,矫直质量直接影响产品质量,所以对其探索新的矫直技术成为亟待解决的问题。对于钛合金管材矫直,若采用双曲线多斜辊矫直机进行矫直,会使管材头尾得不到矫直;若采用二辊矫直机,因为钛合金弹性模量小,反弯半径小,使用单向反弯二辊辊型必然使辊端辊腰半径差加大,使咬入倾角过大产生应力集中降低矫直质量,使用双向反弯辊型因其屈服极限高矫直力就会加大,不利于矫直。本文研究了复合辊型矫直机对钛合金管材的矫直过程,管材先经前置六个双曲线辊矫直,再经后置二辊进行头尾补充矫直使其全长得到矫直,并且从整体设计角度对二辊辊型进行了设计。本文根据塑性变形深度的不同,给出了考虑金属强化时管材弯矩计算模型,与以往对其推导方式不同。在此基础之上,研究管材反弯弹复过程,为减小矫直辊端与辊腰直径差,对二辊辊型进行较短辊身长度设计,使辊型平缓,通过编程计算不同反弯曲率比下的残余曲率比,来确定最佳反弯曲率比组合以弥补较短辊长设计对矫直精度的影响,使管材在此种辊型设计下达到最高的矫直精度。确定辊型结构参数之后,求解了辊型曲线,并编辑了辊型设计可视化界面。通过有限元软件对复合辊型矫直机的矫直过程进行仿真,分析了整个矫直过程中的应力、应变和矫后管材残余应力。分析了不同压弯量和压扁量下管材的残余应力、直线度等参数并对矫直最佳压扁量和压弯量进行选取。对于管材在后置二辊为单向反弯辊型和双向反弯辊型下的矫直质量进行对比,选择最佳辊型并且进行辊型修正降低了管材残余应力,提高了直线度和圆度。最后,复合辊型矫直机与六辊双曲线辊型矫直机矫直质量进行对比,可看出其解决了管材头尾矫直的问题且使管材全长矫直精度有所提高。
[Abstract]:With the wide application of titanium alloy pipe in the fields of aviation, aerospace and ship, the demand and quality requirements for titanium alloy pipe are more and more high. Straightening is the key process in the production of titanium alloy pipe, and straightening quality directly affects the product quality.Therefore, to explore new straightening technology has become an urgent problem.For titanium alloy pipe straightening, if a hyperbolic multi-oblique roll straightening machine is used to straighten the pipe, the head and tail of the pipe will not be straightened; if a two-roll straightener is used, because the titanium alloy has a small elastic modulus and a small reverse bending radius,The use of unidirectional reverse bending two-roll profile will inevitably increase the difference of roll waist radius at the end of the roll and cause stress concentration to decrease the straightening quality due to excessive bite angle. The use of two-way reverse bending roller will increase due to its high yield limit straightening force, which is not conducive to straightening.In this paper, the straightening process of titanium alloy pipe by compound roller straightening machine is studied. The tube is straightened by six front hyperbolic rollers, and then by two rollers after which the full length of the pipe is straightened by the head and tail supplementary straightening.And from the overall design point of view of the two-roll design.According to the different depth of plastic deformation, a calculation model of pipe bending moment considering metal strengthening is presented in this paper, which is different from the previous derivation.On this basis, the reverse bending process of pipe is studied. In order to reduce the diameter difference between straightening roll end and roll waist, the short roll body length is designed to make the roll shape smooth, and the residual curvature ratio under different ratio of reverse bending rate is calculated by programming.In order to make up for the influence of short roll length design on straightening accuracy, the best combination of reverse bending ratio is determined to make the tube achieve the highest straightening accuracy under the design of this kind of roll shape.After determining the structural parameters of the roll profile, the roll profile curve is solved and the visual interface of the roll profile design is edited.The simulation of the straightening process of the compound roller straightener was carried out by finite element software, and the stress, strain and residual stress of the tube after straightening were analyzed.The parameters of residual stress and straightness of pipe under different bending and flattening quantities are analyzed and the optimum flattening and bending amount are selected.The straightening quality of pipe is compared under the condition that the back two rollers are unidirectional reverse bending roll and bidirectional reverse bending roll. The optimum roll shape is selected and the residual stress of pipe is reduced and the straightness and roundness are improved.Finally, by comparing the straightening quality of compound roller straightening machine with that of six-high hyperbolic roller straightening machine, it can be seen that the problem of pipe head and tail straightening has been solved and the straightening accuracy of the whole length of pipe has been improved.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG333.23

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