环坯温度分布状态对径轴向轧制变形遗传影响

径轴向轧制是制造大型无缝锻态组织环件的先进塑性成形工艺。径轴向轧制生产中,由于环坯锻造时不同部位的变形和传热条件不同,导致环坯温度分布不均匀,会对轧制过程环件变形和组织演变产生不同的遗传影响,而现有的研究都忽略了这一因素。为此,采用仿真模拟分析方法来研究环坯温度分布状态对径轴向轧制变形的遗传影响。基于SIMUFACT有限元分析软件平台,建立42CrMo大型环件径轴向轧制三维热-力-组织多场耦合仿真模型,并通过耦合环坯冷却模型建立6种不同环坯温度分布状态。通过模拟分析,研究6种环坯温度分布状态对轧制成形环件应变、温度及晶粒尺寸大小及分布的不同遗传影响规律。结果表明,环坯上下表面低温分布状态导致环件轴向应变、温度和晶粒尺寸均值减小,轴向应变均匀性增加、轴向温度和晶粒尺寸均匀性减小;环坯内外表面低温分布状态导致环件径向应变、温度和晶粒尺寸均值减小,径向应变均匀性增加,径向温度和晶粒尺寸均匀性减小。研究结果为径轴向轧制合理调控环坯温度分布状态从而提高成形环件质量提供科学依据。     

控制轧制与控制冷却--温度控制系统优化

为了提高钢板的性能指标和生产率,对多坯轧制的节奏控制和温度控制数学模型进行研究,并运用到实际生产中.本文给出了利用待温时间和变形温度设计轧制节奏,温降方程来确定轧制区段温度.     

电渣熔铸500轧机辊坯试验研究

通过对电渣冶炼工艺、异型结晶器的编制、设计,成功生产出电渣熔铸覫500辊坯,试验证明电渣重熔冶炼工艺是合理的,轧辊在高温下轧制时,强度能够满足要求。     

履带钢多坯型生产工艺研究与应用

文章分析了型钢厂异型钢生产的概况以及履带钢产品多坯型生产技术的难点,通过“切分共轭孔型设计轧制技术”“有限元模拟技术的应用”“双导轮滚动导卫在型钢产品的应用”及“反弓板面矫直技术”等一系列先进技术应用,成功实现履带钢产品多坯型生产。     

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.     

加速异型钢管轧制工艺和轧制设备的研究

简要说明了异型钢管的市场需求以及国内异型钢管轧机研制的现状,介绍了异型钢管轧制工艺和设备的研究方向.     

活塞环用异型截面型材轧制的显式动力学有限元分析

利用大型通用显式动力有限元分析软件ANSYS/LS_DYNA对活塞环用6Cr13Mo钢异型截面型材的轧制进行了有限元模拟,详细介绍了有限元模型的建立、材料模型的选择以及网格的划分,得到了各道次轧制金属的流动规律,对轧件的变形及轧制区内应力场的分布进行了深入的分析,为成型轧辊的设计以及优化生产工艺提供了参考.     

微细扁线材恒张力绕卷系统

介绍了一种恒张力收卷微细扁线材的结构及控制策略。针对微细扁线材能承受的张力小、容易变形或断裂等特点,开发了一种绕卷结构,以速度和位置作为双重模式调控来获得小张力并保持恒定。通过实验检验,该结构能稳定收卷截面为0.12 mm ×0.05 mm的微细线材,并能自动适应不同的轧制成型速度。     

SPHC系列钢种连铸坯表层夹渣缺陷手工清理工艺改进研究

连铸过程结晶器内的高温氧化物卷入容易造成连铸坯表层夹渣缺陷,直接影响铸坯热轧轧制质量。通过不断探索和现场试验,发现了SPHC系列钢种连铸坯表层夹渣缺陷的分布规律,并通过改进手工火焰清理工艺,大幅减少了连铸坯表层夹渣缺陷,有效提高了连铸坯热轧轧制质量。     

双相钢铸坯表面孔状缺陷热轧过程演变规律

针对双相不锈钢在铸坯易出现因氮气上浮形成孔状缺陷的问题,在铸坯上进行热轧轧制,发现铸坯表面孔状缺陷随轧制过程的演变规律,确定可增加轧制道次,消除缺陷。     

H型钢轧制过程摩擦力分布的数值分析

为了分析万能法轧制H型钢过程中不同接触区内摩擦力分布的规律,利用数值模拟法建立了H型钢的轧制模型。以铅为坯料,在给定轧制规程的前提下,系统地模拟了H型钢轧制的全过程;分析了翼缘和腹板变形区的长度、宽度等参数;最终获得了稳态轧制过程中摩擦力在不同接触区域内的矢量分布规律。研究结果表明:H型钢翼缘表层金属受到的摩擦力的方向指向变形区的中部,翼缘变形区存在前滑区和后滑区;H型钢腹板表面金属受到的摩擦力的方向一致,与轧制的方向相反,使得接触区基本为后滑区。     

Analysis of railway wheel rolling process based on three-dimensional simulation

Rolling is one of the key stages of railway wheel hot forming process. In this work, a three-dimensional finite element analysis on wheel vertical rolling process based on some strategies proposed has been carried out by using FE code SuperForm. In modeling, a virtual mandrel is exploited in the hub hole to keep the wheel central instead of the guide rolls and centering rolls. Some features of the wheel forming are deeply investigated such as the rim diameter expanding, the rim lateral spreading, the metal flow in the circumferential direction, and the stresses distribution. The results show that (1) the rim radius expanding mainly occurs in the two affected zones before and after the back roll deformation zone; (2) the rim metal has flow trend in the circumferential direction during rolling, the metal of the intersection area, between the tread and the rim external side surface has the largest relative angular displacement; and (3) the tensile stresses of the web both in radial and circumferential directions during rolling result in the web thickness decreasing by about 3 mm for the investigated wheel. The simulations results reveal the forming mechanisms of wheel rolling, laying the basis for designing and optimizing railway wheel forming process.     

材料参数对环件冷辗扩工艺的影响规律研究

基于ABAQUS软件环境,采用弹塑性动态显示有限元法,通过三维数值模拟研究揭示了几个重要的材料参数(硬化指数、屈服强度和弹性模量)对环件冷辗扩过程中环件端面质量、轴向宽展、辗扩力、辗扩力矩以及金属流动特性的影响规律,并从金属塑性成形原理和塑性加工力学等角度对这些规律进行了合理的解释,从而获得了何种材料性能适应冷辗扩成形的认识,为环件冷辗扩在实际应用中材料和设备的选择提供了依据,对揭示冷辗扩成形机理也具有十分重要的意义。     

Effects of rolling parameters on work-roll temperature distribution in the hot rolling of steels

Temperature variations of work-rolls in the process of hot rolling of slabs were analyzed by solving heat conduction equation with time-dependent boundary conditions. The Raylieght-Ritz and the finite-element methods were employed to solve the governing equation. To improve the accuracy, the thermal relationship between rolling metal and work-rolls was taken into account as well as the effects of different parameters such as interface heat transfer coefficient, rolling speed, and slab initial temperature were considered in the calculations. To verify the employed model, a comparison was made between the predicted and the recorded time-temperature history and good agreement was observed. Modelling results show that the interface heat transfer coefficient and rolling speed are important factors that vary effectively the temperature field within the work-roll. In addition, the interface heat transfer coefficient is affected by the other parameters and factors such as flow stress behavior of the metal being rolled and initial temperature of metal. Therefore, in order to determine an accurate temperature field within the work-rolls, flow behavior and temperature distribution in the rolling metal should also be calculated at the same time.     

Roll System and Stock’s Multi-parameter Coupling Dynamic Modeling Based on the Shape Control of Steel Strip

The existence of rolling deformation area in the rolling mill system is the main characteristic which distinguishes the other machinery. In order to analyze the dynamic property of roll system’s flexural deformation, it is necessary to consider the transverse periodic movement of stock in the rolling deformation area which is caused by the flexural deformation movement of roll system simultaneously. Therefore, the displacement field of roll system and flow of metal in the deformation area is described by kinematic analysis in the dynamic system. Through introducing the lateral displacement function of metal in the deformation area, the dynamic variation of per unit width rolling force can be determined at the same time. Then the coupling law caused by the co-effect of rigid movement and flexural deformation of the system structural elements is determined. Furthermore, a multi-parameter coupling dynamic model of the roll system and stock is established by the principle of virtual work. More explicitly, the coupled motion modal analysis was made for the roll system. Meanwhile, the analytical solutions for the flexural deformation movement’s mode shape functions of rolls are discussed. In addition, the dynamic characteristic of the lateral flow of metal in the rolling deformation area has been analyzed at the same time. The establishment of dynamic lateral displacement function of metal in the deformation area makes the foundation for analyzing the coupling law between roll system and rolling deformation area, and provides a theoretical basis for the realization of the dynamic shape control of steel strip.     

Mechatronic simulation of the 300 rolling mill

Attempts are made to improve metal rolling on the basis of models of the mechatronic system in the 300 rolling mill. The relations between the electric drive, the rolling stands, and the deformed metal are taken into account here.     

Research on forming precision of flexible rolling method for three-dimensional surface parts through simulation

Flexible rolling is a novel forming process for three-dimensional surface parts using a pair of bendable rolls. By controlling the distribution of the gap between the upper and lower forming rolls in the rolling process, the sheet metal is nonuniformly thinned in the thickness direction and the longitudinal elongation is different in the width direction of the sheet metal, which makes the sheet metal deform in rolling direction. With the rotation of the bendable rolls, the sheet metal is deformed consecutively and a three-dimensional surface part could be obtained. A small experimental device has been designed. Finite element analysis (FEA) model is established. Spherical surface and saddle surface are simulated, and their experimental results are presented. The major purpose of the present work is to analyze the forming precision of flexible rolling and the reasons for the shape errors through simulated and experimental results. The results demonstrate that the proposed process is a feasible and effective way of forming three-dimensional surface parts.     

[成形过程仿真优化与集成计算材料工程]限动芯棒连轧管机轧制过程轧件变形行为及规律仿真

基于ABAQUS有限元软件建立了180 mm限动芯棒连轧管机组钢管连轧过程仿真模型。通过仿真模拟展现了连轧各机架连续轧制过程中轧制区钢管横截面上应力、应变及位移的分布和壁厚形成演变过程,揭示了轧制压力分布和轧辊上总轧制力的变化规律以及轧件温度与轧制区摩擦因数对壁厚与轧制力的影响。使用三次样条插值方法从仿真结果数据中提取钢管壁厚和直径,通过研究对象机组的工业生产实测数据验证了有限元模型的正确性。仿真发现:连轧过程中,金属在纵向上先发生减径变形后发生减壁变形,横向上金属主要从孔顶区流向开口区;前三机架接触压力主要集中在孔顶区,变形量较大,是主变形机架,第四五机架接触压力最大在侧壁区,变形量较小,主要起到精整和归圆作用;随着轧制温度的升高,出口壁厚增大,轧制力减小,随着芯棒与轧件之间摩擦因数的增大,壁厚减小,轧制力减小。仿真研究结果支撑了针对该机组的关键轧机结构参数设计、轧制工艺参数确定以及工程调试中工艺参数优化。     

Optimal contact design and allowable limit on spindle assembly of aluminum hot rolling process

Aluminum sheet ingots go through the hot rolling process to be converted into coils with a gauge suitable for the cold rolling process or plates. The top spindle, end coupling and slipper metal are main components of the hot roll process and used for transmission of rotational power with heavy-duty load. The top spindle connected to the motor and end coupling connected to the roller are combined with the slipper metal which acts as a bearing and joint. The contact surface between end coupling and slipper metal is subjected to stress concentration, and life cycles of slipper metal is reduced. This study aims to minimize the mechanical problems which might happen in the production process. The load condition for hot rolling processes is derived under load condition that is conducted for a hot rolling process under slipper metal combination types and operation situations. A structural analysis is performed by applying mechanical characteristics, combination type, and rotational boundary condition of top spindle, end coupling and slipper metal. Optimal design is performed for contact surface between end coupling and slipper metal. Interference analysis is studied to reduce the stress concentrations. Kinematics simulation is performed by applying the various combination type and dynamic boundary condition of the mill spindle assembly. The interference does not occur on the top spindle and slipper metal, so actual driving of the hot mill spindle assembly can operate in the normal operation condition.     

对滚轧小模数渐开线花键轧辊结构的改进与研究

分析了在滚丝机上滚轧加工小模数渐开线花键轴成形理论，并根据金属变形走向和采用复杂刀具的分层切削原理，制造了一种分层压入的纵向齿纹轧辊。介绍了这种轧辊的优点，分析了滚轧过程申出现多齿、少齿或斜齿现象的原因并提出了相应的解决办法。