多楔同步楔横轧金属流动分析及缺陷防止对策

针对多楔同步楔横轧工艺的特点,分析了不等直径轧件双楔平行同步楔横轧工艺和叠楔同步轧制工艺金属扭转情况,提出了减轻轧件扭转现象的措施;还分析了双楔平行同步轧制工艺轧件表面形成夹层和螺旋压痕等缺陷的原因,并提出了消除此类缺陷的楔形设计方法。     

大螺距实心螺纹件的楔横轧新工艺

在楔横轧工艺的基础上,对大螺距实心螺纹件的快速成形工艺进行了试验研究。采用文中新工艺轧出了合格的铁道用螺钉,轧制生产率高,成本低,提高了楔横轧工艺技术水平。     

多楔同步楔横轧工艺研究通过技术鉴定

由兵器工业第五九研究所承担的“多楔同步楔横轧工艺研究”项目,1992年5月13日在重庆通过机械工业发展基金委员会组织召开的技术鉴定。鉴定委员会认真听取了课题组提出的“研究报告”、“楔横轧模具的楔形参数的选取报告”和“多楔同步楔横轧金属流动分析及轧件缺陷防止对策报告”,观看了现场录相,审查了全部技术文件。一致认为,课题对多楔同步楔横轧的轧辊孔型设计方法进行了较深入的理论分析研究,提出了独特的设计见解,得出了多楔同步轧制工艺的实用设计计算公式,并在试验中应用,得到了较好的效果,     

可移式模具在楔横轧工艺中的应用

通过使用可移式轧辊模具 ,成功地利用一副模具轧制出了形状相似、仅局部尺寸不同的多种规格的阶梯轴 ,使楔横轧工艺在规格较多、批量较小的轴类零件毛坯成形中得到了应用 ,楔横轧技术得到了进一步发展和推广。     

楔横轧变形接触面的螺旋面方程及其应用

建立了楔横轧变形工件与模具接触面的旋转螺旋面方程。利用新方程求解工程问题,其结果比用传统的用圆锥曲面近似求解有明显改善。螺旋面方程的建立为楔横轧工程问题的精确求解创造了条件。对于研究楔横轧理论。提高工艺水平有一定的促进作用。     

楔横轧模具的铣削加工及其机床设计

根据楔横轧模具孔型及其加工成形的特点,对楔横轧模具大面积大螺距楔形提出了一种简单高效的铣削加工方法,并设计制造了楔横轧轧辊模具孔型加工专用机床——SDM机床。新设计的SDM机床投资小,可以加工直径为φ620 mm～φ1000mm的轧辊模具,加工导程最大可达469 mm,加工周期短,成本低,且大大降低了工人劳动强度。     

多楔同步楔横轧工艺研究通过鉴定

由吉林工业大学辊锻工艺研究所承担的。多楔同步楔横轧工艺研究”课题鉴定会,于一九九○年十二月二十二日在吉林工业大学召开。哈尔滨工业大学霍文灿教授和东北工学院栾瑰馥教授任鉴定委员会正副主任委员。鉴定委员会认真听取了课题组提出的“国内外水平对比报告”,     

楔横轧力参数的实验研究(1)

本文介绍了楔横轧力参数的测定方法,并对部分实验结果进行了分析。     

XM50齿轮轴毛坯楔横轧和箭形零件成形工艺通过鉴定

“楔横轧制坯工艺研究”和“箭形零件成形工艺研究”,是由兵器部六二研究所承担的部控研究课题。楔横轧课题在实验的基础上选择了生产量大,形状较复杂,具有一定代表性的XM50型摩托车发动机的齿轮轴作为课题的研究对象。这两项工艺研究课题的鉴定会于1986年12月2日～4日在重庆召开,参加会议的有来自兵器部、局、大专院校、研究所和工厂等十六个单位的专家、教授、工程技术人员共23名。中国特种轧制学会主任胡正寰教授主持     

楔横轧轴肩的成形曲面的设计

此文分析在二辊楔横轧中轧制各类轴肩的过程。在假想工件轴端固定的图上确定楔侧面截面轮廓形状,再通过叠加轴向刚性移动量确定各截面实际位置,比较直观简便地设计出轧制轴肩的辊面上的成形曲面。最后归纳了设计步骤。     

Stability Analysis of Chatter on a Tandem Rolling Mill

Accurate prediction of the onset of chatter is difficult in designing and operating a rolling mill. Both the lack of precise rolling process models and analytical methods for the investigation of mill stability have forced designers and users to rely on experience and trial and error, which are time consuming and cost demanding. A comprehensive rolling process model is introduced to form the foundation of chatter analysis that includes a range of possible process variations. Analytical chatter models for both single and multiple-stand rolling mills are constructed that account for interactions between mill structure and rolling process, as well as between adjacent stands. Stability analysis is performed to formulate criteria for rolling mill design and operation. Finally, simulations and experiments are presented to verify some basic components of the rolling process model that constitute the proposed chatter models.     

径轴向辗环机优化轧制规程的计算机辅助设计

此文介绍了利用数字计算机进行矩形截面环轧制的优化规程设计方法,优化是基于轧制过程的物理模型,考虑了各种轧制约束条件,结果符合实际生产情况,并且可使轧机容量得到充分利用,大大缩短轧制所需时间,节约材料与能源消耗。     

Design of Profile Ring Rolling by Backward Simulation Using Upper Bound Element Technique (UBET)

The upper bound element technique (UBET) is used to determine the optimum intermediate shape for profile ring rolling using backward simulation. The lowest energy rate is the key issue in achieving the optimal intermediate shape as well as the backward simulation of the process. The plastic flow of material in ring rolling is assumed to be a sequence of successive closed-die forging processes. The ring is divided into features, which provide an approximated profile consisting of a number of rectangular elements. The simulation of the profile ring rolling was tested with different profiles of rolls, and two such cases are presented here. The present method was validated using an experimental radial ring rolling mill designed and fabricated in the Dept. of Mechanical Engineering at Ohio University for the investigation of both cold and hot ring rolling processes. As the results show, this technique is capable of solving the backward simulation of profile ring rolling problems in a much shorter time compared to the finite element method (FEM), which cannot easily simulate profile ring rolling. Moreover, as an engineering tool, this approach can be applied effectively to the profile ring rolling process and can serve as a useful tool in industrial applications.     

PVD coated mill rolls for cold rolling of stainless steel strips—Tribological and mechanical laboratory tests

The cost of rolling is determined in particular by productivity and lifetime of rolls before regrinding. Adhesive wear of the sheet gives rise to transfer on the roll surface. Its occurrence depends on rolling conditions and is one of the determining factors of the maximal reduction for a given rolling speed. Abrasive wear of the roll is the second factor for roll lifetime. Both phenomena are strongly related to tribological and mechanical characteristics of the surface layer of rolls. Stainless steel is known for its high adhesiveness. Coatings with good tribological properties could help extend the roll service. In this paper, the potential of different PVD coatings (CrN, TiN and TiBN) is explored. The impact of these coatings on influential phenomena during rolling is analyzed thanks to well-adapted tribological and mechanical laboratory tests. The results show that TiN has a good potential in cold rolling of stainless steel strips.     

The effect of cold rolling on the foaming efficiency of aluminium precursors

The objective of the present study is to investigate the role of cold rolling on the foaming ability (or foamability) of aluminium precursors, made by continuous rotary extrusion, a process performed at elevated temperature, starting by powder. For this purpose, the effect of different parameters including initial shape of precursors, rolling direction, amount of deformation in each rolling pass and final thickness of rolled specimens are experimentally investigated. Furthermore, the foaming efficiency of both rolled precursors and as-received extruded ones is compared. To clarify the role of secondary processing operations on the foaming efficiency, precursor samples are prepared following different forming and machining process chains, before the final foaming operation. Finally, hardness tests are performed on as-received precursors and rolled samples to notice the correlation between rolling parameters, state of strain, foaming efficiency and hardness. The results of the study show that: (a) cold rolling considerably improves foamability, (b) rectangular precursor bars have higher foaming efficiency than round ones, both before and after cold rolling. Besides, the improvement in foamability due to cold rolling is greater if precursors are rolled in the extrusion direction, rather than the orthogonal direction.     

采用大变形弹塑性有限元法对带材异步冷轧过程的数值模拟

此文采用纠正的拉格朗日列式和基于弹塑性乘法分解的超弹性塑性本构关系,对铝带在不同轧制条件下的异步冷轧过程进行了大变形弹塑性有限元模拟.结果表明,在异步轧制时,轧制力对工作辊辊径的变化表现出非敏感性,而且由于搓轧区的存在,使得变形区内静水压力的绝对值比同步轧制时要小得多.     

铝合金复合板轧制变形规律研究

此文研究了Al-Si/Al-Mn/Al-Si三层铝合金复合板轧制过程中包覆率的变化规律,基体金属和包覆金属的变形速度关系。讨论了复合板的变形规律。     

方轧件在椭圆孔型中轧制温度场的三维有限元分析

应用MARC/autoforge有限元软件对方轧件在椭圆孔型中的轧制温度场进行了热力耦合模拟.研究了模拟过程中的传热边界条件,分析了轧制前和轧制过程中轧件中温度场的分布和变化规律.模拟计算结果和实验结果的比较说明二者基本是相符的.     

非对称交叉轧制压力研究与分析

对冷轧条件下非对称交叉轧制情况下变形区金属流动状态进行了分析 ,建立了总轧制压力计算公式 ,并用理论与实验两方面进一步分析了轧制压力与交叉角之间的关系。     

车门框条滚压成形工艺及滚压线设计

以X110型车门为例,分析零件工艺性,介绍滚压成形工艺过程,强调在模具设计和制作中应注意的问题。设计由滚压、校正、滚焊和自动断料等工艺流程组成的滚压线,可作为类似滚压工艺参考。