基于空间啮合理论的环件轧制轧型设计

分析了环件轧制变形的啮合运动性质,基于空间啮合理论建立了环件轧制孔型的一般设计方法,并进行了实例设计计算。本文解决了复杂形状环件轧制孔型设计理论问题,对于环件轧制技术的应用和发展具有实际意义。     

环件轧制原理和设计方法

分析了环件轧制变形特点，提出了环件轧制咬入、锻透和弯曲力学模型，建立了环件轧制咬入条件、锻透条件和刚度条件，阐明了环件轧制原理。基于环件轧制原理，建立了环件轧制技术设计方法，导出了轧制用毛坯。孔型和轧制进给参数设计计算公式。根据环件轧制试验结果，对其咬入条件和锻透条件进行了验证。     

内台阶锥形环件轧制三维有限元模拟和工艺优化设计

以Abaqus三维有限元模拟软件为平台，对内台阶锥形环件的轧制过程进行了数值模拟，通过模拟计算揭示了内台阶锥形环件轧制缺陷的形成机理。根据轧制难度分析和有限元模拟结果，对轧制毛坯尺寸和轧制孔型进行了优化。采用铅环件试样在D51—160轧环机上进行了内台阶锥形环件的轧制试验，轧制了合格的内台阶锥形环件。模拟和试验结果表明，轧制毛坯尺寸和轧制孔型优化方案是合理的，基于变形模拟的轧环工艺优化方法是有效的。     

环件径轴向轧制过程锥辊旋转运动学分析

稳定轧制是环件径轴向轧制过程保证产品质量的重要条件之一.文中基于几何关系和运动学原理,对环件径轴向轧制过程中锥辊与环件接触区旋转运动进行了研究,结果表明:轴向锥辊在与环件接触面处的旋转线速度尽量保持一致非常关键,轧制过程中应尽可能地保证锥辊锥顶点位于环件的圆心处.锥辊转速大于环件转速时,应增大径向孔型中的轧制力矩,使环件重新稳定;锥辊转速小于环件转速时,会导致轧制无法正常进行,出现环件位置严重偏移或卡环等现象.     

轧环机进给速度设计

环件轧制是轴承、齿轮、法兰、轮箍等环形零件或毛坯的重要生产工序,在机械、汽车、航空等工业中得到了广泛应用。环件轧制原理如图所示,驱动辊同时作旋转轧制运动和直线进给运动,芯辊和导向辊为轴线固定的空转辊,可通过接触摩擦随环件一起转动;轧制时由于驱动辊的作用,环件不断地咬入驱动辊与芯辊构成的轧制孔型或辊缝,产生壁厚减小直径扩大的塑性变形,最终成为具有一定壁厚和直径的环件制品。环件轧制中,轧辊     

风电轴承环成形缺陷数值模拟与工艺优化

风电轴承环属于大型异形环状零件,环件轧制技术是目前成形该类零件的主要方法。环件轧制过程中金属流动复杂,轧制孔型与环件之间接触情况复杂,同时由于轧制用毛坯、轧制工艺参数等原因,导致轧制过程中出现多种缺陷,缺陷的出现降低了环件质量,甚至使零件报废。该文针对风电轴承环轧制过程中出现的直径不扩大、椭圆度缺陷,运用Deform 3D软件对0134090003p6轴承成形过程进行模拟,提出当环件轧制到一定尺寸时,改用胀形工艺成形,获得了精度较高的环件,该工艺具有一定工程实用价值。并运用正交试验设计,发现影响胀形环件综合性能的主要因素是胀形坯料的尺寸形状,同时得到了该工艺的近似最优参数组合。采用粒子群优化算法优化相应的SVR参数,用训练好的SVR模型对胀形结果进行预测,得到一个可以预测环件胀形性能的SVR模型,该模型对工程实践有较好的辅助价值。     

环件径轴向轧制中轴向爬升机制与抑制方法研究

环件径轴向轧制过程是多运动耦合作用下的复杂动态变形过程,轧制过程中容易出现各种不稳定现象,研究针对环件在径向孔型中沿轴向向上爬升（又称爬辊）的轧制失稳现象, 首先运用力学理论,分析了环件在径轴向轧制过程中的受力状态,揭示了其爬辊现象产生的力学机制,然后提出了一种基于导向辊的形状与分布优化设计的爬辊现象抑制方法,并通过有限元模拟和实验验证了该方法的有效性。研究结果为实际生产中有效地解决爬辊现象提供了科学指导依据。     

大型L形环件径轴向轧制成形仿真分析

环件径轴向轧制工艺是生产大型环锻件的一种先进加工技术,目前关于大型异形环锻件的径轴向轧制成形理论和工艺的研究相对较少,无法为该类型环件实际轧制生产提供指导。因此,本文为主要针对工程机械用大型L环件的稳定轧制问题,采用优化的毛坯设计控制环件精密成形,采用轧辊分级降速控稳定轧制,借助有限元软件ABAQUS进行仿真建模与分析。研究结果对于该类型环件的径轴向轧制工艺设计具有重要意义。     

超大型环件径轴向轧制过程偏移机理及自适应模糊控制方法研究

超大型环件径轴向轧制过程容易产生偏移,影响环件轧制稳定性和成形质量。为研究环件偏移机理及其控制方法,分析了轴向孔型滑移区中前滑区和后滑区的分布变化规律,建立了理想情况下不产生环件偏移时锥辊旋转运动学条件,获得了滑移区的最优速度匹配系数。此外,从历史轧制数据中归纳人工控制经验后提出了基于锥辊转速自适应模糊调节的环心偏移量控制方法,基于ABAQUS软件和VUAMP子程序开发,建立了集成有环心偏移量模糊控制算法的?10 m超大型环件径轴向轧制有限元模型,研究了采用最优速度匹配系数的常规控制和自适应模糊控制下的环心偏移量变化规律。结果表明,自适应模糊控制下的平均环心偏移量相比于常规控制降低了72.4%,仿真结果和试验数据均验证了所提超大型环件轧制过程偏移自适应模糊控制方法的有效性。     

环件辗轧过程建模

在论述环件轧制过程与特征的基础上,对热态矩形截面环轧制的数学模型作了初步探讨,分析了液压伺服控制系统与环件轧制的关系。所建立的轧制模型可用于环轧控制系统的设计与轧制规程的优化,对环件轧制预测和实际生产有重要的指导意义。     

沟球断面环件冷辗扩三维有限元模拟与工艺设计

沟球断面环件冷辗扩是滚珠轴承套圈制造新工艺。以有限元软件Abaqus为平台,根据冷辗环机实际工作条件,建立从矩形断面毛坯冷辗扩成形沟球断面环件的三维弹塑性动力显式有限元模型。通过动力显式有限元数值模拟,研究沟球断面环件冷辗扩变形过程,揭示出该环件冷辗扩中直径增长和圆度变化规律。基于数值模拟结果,优化设计矩形断面环件毛坯尺寸和冷辗扩工艺参数。在D56G90冷辗环机上进行沟球断面环件冷辗扩试验,验证了数值模拟结果,并采用矩形断面环件毛坯成功冷辗扩出了沟球断面轴承套圈。     

Modeling and simulation of cold rolling process for double groove ball-section ring

Double groove ball-section ring (DGBR) is an important part of bearing rings. Cold DGBR rolling is an advanced continuous and local plastic forming technique by reducing cross section and increasing the diameter of ring blanks between rotating roll, and can directly obtain the DGBR with good mechanical properties. In this paper, the cold DGBR rolling processes from some initially rectangular blanks are investigated by using 3D-FE numerical simulation to reveal its deforming rules. Firstly, by analyzing the dimension relationship between rectangular blank and deformed ring, a new blank size design method is proposed based on rolling ratio and the volume conservation law, and thus a series of different original blanks can be precisely designed under different rolling ratios for a same final required DBGR. Secondly, under the ABAQUS/Explicit software environment, a reliable guide roll adaptive control-based 3D-FE model for cold DGBR rolling process is built via elastic–plastic dynamic explicit finite element method. Finally, several rectangular blanks are designed under different roll ratios and the deforming behaviors of cold DGBR rolling process are investigated with thorough numerical simulation. The results show that: (1) the maximum radial thickness of ring H reduces firstly slowly and then rapidly after the ball groove achieves its final shape; (2) the diameters of the ring expand gradually during the whole process and no sudden change occurs just when the final shape of the ball groove is completely formed; (3) the largest deformation occurs around the ball groove all the time under small rolling ratio; while under large rolling ratio, it occurs first around the ball groove and then gradually transfers to the ring outer surface; and (4) the inhomogeneous deformation degree increases with the progress of the process, and for final parts, it increases slowly first with the increasing of roll ratio and then fast when the roll ratio is greater than a certain value. These results will not only reveal the forming mechanisms of cold DGBR rolling process but also provide a basis to blank optimum design and process adaptive control of the relevant profiled ring rolling processes.     

环件辗扩成形过程微观组织及性能控制研究进展

高性能大型环件精确辗扩控形控性一体化制造是大型运载火箭仓体、风电法兰、核电反应堆及石油化工容器等高端装备向着安全、轻量、高效和长寿命方面发展的迫切需求。综述环件辗扩成形过程微观组织及性能研究现状,分析单、双道次简单热模拟压缩试验和显微组织演变数值模拟技术在环件辗扩过程组织演变研究中的应用,探讨环件组织与性能控制中存在的问题,并指出目前的研究已无法满足上述高性能环件制造要求。提出复杂多道次物理模拟及内变量组织建模用于环件辗扩组织演化分析的必要性,探明环件宏观/微观织构定量表征和晶体塑性有限元法(Crystal plasticity finite element method,CPFEM)揭示组织演变机理的可行性。阐述今后高性能环件辗扩成形组织演变及性能控制的研究方向与重点,未来必须构建辗扩过程环件组织、织构和力学性能之间及其与工艺参数的定量关系。     

Analysis of plastic penetration in process of groove ball-section ring rolling

Plastic penetration is a necessary condition of ring rolling forming. In this paper, based on the principle of groove ball-section ring rolling and characteristics of plastic penetration, a three dimensional (3D) finite element (FE) analysis model for the plastic penetration of ball groove-section ring is established under the ABAQUS software environment. A decisive factor for plastic penetration behavior, namely the penetration speed of plastic zone, has firstly been ascertained. The distribution pattern of the plastic zone in the process of plastic penetration is revealed by 3D simulation. By researching the diffusion rules of the plastic zone under the conditions of different ring radial thickness and feed speed, the influences of ring radial thickness and feed speed on plastic penetration are obtained. Lastly, the necessary condition for the plastic penetration of groove ball-section ring rolling is summarized, and is validated by experiment and simulation. The achievements of this study expressly reveal the plastic penetration rules of groove ball-section ring rolling, and it’s useful for technology design and production.     

Analysis of guide modes in vertical hot ring rolling and their effects on the ring’s dimensional precision using FE method

In the vertical hot ring rolling (VHRR) process, roundness, outer radius, and width spread are three important indexes to the formed ring’s dimensional precision. In this paper, features of the guide modes of the VHRR process, such as single fixed guide mode (SFGM) and single follow-up guide mode (SFUGM), are analyzed to investigate their effects on the ring’s dimensional precision. The geometrical models of all the guide modes are then established and reliable three-dimensional coupled thermal-mechanical elastic-plastic FE models of the VHRR process are developed in ABAQUS/Explicit. Some key technologies, such as the guide roller’s motion control, are reasonably dealt with. The research results show that: (1) The roundness of the rings rolled by SFUGM is obviously superior to that of the ring rolled by SFGM. (2) With the same feed amount, the outer radius of the ring rolled by SFGM is always larger than that of the rings rolled by SFUGM. (3) During the rolling process of the ring rolled by SFGM, severe eccentricity will exist at the ring’s center, which is not obvious in the rolling process of the ring rolled by SFUGM. (4) The average value of width spread of the ring rolled by SFGM is slightly larger than that of the rings rolled by SFUGM. The research results can yield an understanding of some phenomena in the VHRR process. The modeling methods presented in this paper have general significance in the study of the VHRR process of the ring with complex profile.     

卷绕成形加工专用机床的设计

卷绕成形加工是指通过一根或数根具有一定廓形的带材卷绕形成零件主体部分的加工方法，该带材称为芯带。实现卷绕成形加工的关键在于芯带的成形和卷绕。文章讨论了芯带成形，卷绕设备，一体化机床及其控制系统的设计，并给出了应用例。     

环件径轴向轧制毛坯尺寸设计方法

毛坯尺寸设计是环件径轴向轧制过程优化设计的前提和基础,合理的毛坯尺寸设计,对于成功建立环件径轴向轧制过程、通过包括毛坯在内的过程优化设计以获得精确的环件尺寸和良好性能,具有十分重要的意义.为此,提出一种基于轧比和径轴向变形量分配比的矩形截面环件径轴向轧制毛坯尺寸设计方法,给出毛坯尺寸的计算公式与确定流程,阐明该毛坯尺寸设计方法的特点及应用范围.该方法基于体积不变原理,针对同一环件的轧制,可以设计不同轧比和变形量分配比的多个环坯,为研究不同环坯下的环件径轴向轧制变形行为、工艺规律以及包括毛坯在内的工艺过程优化设计、成形成性一体化调控提供了重要的方法和基础.     

Towards a steady forming condition for radial-axial ring rolling

Radial-axial ring rolling (RARR) is a typical incremental forming process with high flexibility. It is difficult but essential to establish a successful RARR process and remain its stability by properly designing process variables. This paper is an attempt to develop a steady forming condition under which the RARR process can be established successfully and then proceeds stably with qualified ring rolled parts. For remaining process stability by alleviating dynamic contacts and collisions between the ring and the rolls, constant growth velocity condition (CGVC) of the ring is proposed as a design objective of the process variables. Then a mathematical model of the steady forming condition for RARR is developed based on the CGVC. The model describes both the mathematic correlations and the reasonable ranges of key process variables of RARR, and the application and role of the model are illustrated by a case study in detail. For verifying the steady forming condition for RARR, FE simulations and analyses are carried out through developing reliable 3D-FE models for the entire RARR processes under ABAQUS/Explicit platform. The simulation results show that the designed processes based on the mathematical model of the steady forming condition are successfully operated and have good stability. A value of the growth velocity of the ring, which is close to the median of its reasonable range determined by the steady forming condition, is recommended for the design of the process by taking into account the geometry of the rolled ring, material plastic deformation behavior of the ring and process stability.     

大变形量下高碳钢环件冷轧变形过程模拟与试验研究

研究了大变形量下高碳钢环件冷轧变形行为,利用有限元模拟方法分析了环件冷轧过程中的形变规律,采用光学显微镜、SEM等材料表征手段研究了大变形量下环件冷轧过程中的组织演化特点。结果表明：在较小的变形量下,环件内外侧应变较中间应变大,且变形首先发生在环件外侧;整个环件变形过程中,环件中间层的晶粒变形程度最小,外层次之,内层的变形最为剧烈;铁素体基体沿轧制方向呈现明显的方向性,碳化物颗粒分布更为均匀,且数量变少;随着变形量的增大,环件内层的应变明显大于外层的应变,且最小应变的位置偏移至靠外层比较近的区域,其组织中碳化物颗粒脱落加重;当变形量达到625%时,环件达到塑性极限,在内侧表面产生裂纹发生破坏。