辊式楔横轧楔入轧制几何分析

在对楔入轧制过程分析的基础上 ,建立了辊式楔横轧楔入轧制接触面的数学模型。建立了轧制接触面方程及其边界方程 ,得到了不同工艺参数条件、不同轧制阶段下的接触面几何关系。     

我国平板式楔横轧技术的现状

平板式楔横轧与辊式楔横轧比较,具有模具加工简单、制造费用低,模具可以淬火因而寿命大幅度提高,以及在工件的两侧不需设置挡板等优点,所以更适合轧制中小型台阶轴类工件。本文综述了平板式楔横轧的工作原理、工艺特点;介绍了我国有关单位在平板式楔横轧设备和工艺研究方面所取得的成果实例。     

重庆建成楔横轧制生产线

重庆长江钢厂投资２５０万元，建成了重庆市第１条Ｈ７５０型二辊式楔横轧制生产线，楔横轧成型工艺是一种轴类零件成型的新技术，是冶金部推广应用的一项节能节材新技术，产品广泛应用于汽车、拖拉机、电机等轴类零件的生产，具有生产效率高，节约材料，减少加工工序，降低产品成本等优点。重庆长江钢厂历经１年半时间，于１９９４年２月底建成Ｈ７５０型二辊式楔横轧生产线，目前设备运转正常。楔横轧制工艺是利用２个装有带楔形模具的轧辊，其轴线平行配置，以相同方向旋转，带动棒料在孔型作用下，经成形精整及切断，轧制成各种阶梯轴类…     

楔横轧凸轮轴轧制半径对辊形曲线影响的规律

为获得楔横轧凸轮轴轧制半径对辊形曲线的影响规律,文章采用DEFORM-3D有限元软件,得到了楔横轧轧件的轧制半径的变化规律,有限元分析表明,轧件的轧制半径在楔入段和展宽段基本不变,精整段前段随楔面升高而变小,轧件成形后轧制半径保持不变,并用实验数据验证了此规律的正确性。在此基础上设计出了楔横轧轧制凸轮轴时轧辊的辊形曲线,应用此辊形曲线进行有限元仿真和实验轧制,取得良好的效果,验证了此种辊形曲线的求解方法的正确性。     

楔横轧多楔轧制力变化规律试验研究

以单楔与双楔楔横轧为例，研制出轧制力在线测试系统，能准确实时地测量出各种工艺参数下楔横轧多楔轧制过程中轧制力的变化全貌；通过对实验结果的分析，得出了楔横轧多楔轧制力的变化规律。     

偏心圆截面轴类零件的楔横轧成形数值模拟

提出了一种偏心轴类零件楔横轧成形新工艺,给出了楔横轧成形偏心轴类零件轧辊的辊型曲面.利用三维弹塑性有限元软件LS-DYNA对一种典型偏心轴类零件楔横轧成形进行了数值模拟,分析了其成形过程、应力应变场分布及工艺特点.模拟结果表明,从起楔开始就将坯料轧制成偏心圆截面的偏心轴类零件的楔横轧工艺是完全可行的,而且具有轧制力小、变形容易控制等优点.     

凸轮轴楔横轧成形仿真与应力应变分析

提出了一种凸轮轴楔横轧成形新工艺,得出了楔横轧成形凸轮轴轧辊的辊形曲线和轧齐曲线.利用三维有限元软件DEFORM-3D对凸轮轴成形进行了数值模拟,在模拟轧制过程中,轧辊楔面排料的同时轧件上的凸轮轮廓也被轧辊上的凸轮凹槽逐渐轧制生成,并且逐渐被轧齐,得出轧件应力、应变场在凸轮顶端和芯部较小,在与轧辊楔面接触处最大,呈非对称分布的特点.模拟结果表明,用楔横轧工艺轧制凸轮轴是完全可行的.     

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。     

铝合金楔横轧轧制技术研究现状

楔横轧轧制工艺以其高效、节能的特点越来越受到关注.模具设计是楔横轧工艺的核心之一,工艺参数的选择是影响轧制工艺正常进行的重要因素.在轧制过程中出现的缺陷严重影响轧件质量,成为制约楔横轧工艺发展的重要因素.本文介绍了楔横轧技术的发展,铝合金楔横轧技术的研究意义,在楔横轧工艺参数和缺陷等方面的研究现状.     

链同步平板式楔横轧机

链同步平板式楔横轧机２２６６００海安锻压机床厂沈瑞宏颜华薛永贵１引言楔横轧成形工艺是近几十年来发展起来的一种少无切削新工艺。到目前为止，楔横轧工艺和设备的研究已取得了较大的进展，开发研制了平板式和辊式两种类型的楔横轧机，并且取得了较好的经济效益和社会...     

一种缸筒类零件内孔的加工方法

介绍了一种缸筒内孔加工方法,它在精镗内孔完成后,再对缸筒内孔进行滚压,其粗镗、精镗和滚压均在采用普通车床改装制成的专用机床上进行。这种缸筒内孔的加工方法与现有技术相比,可解决现有缸筒内孔废品率高、加工成本高的问题。     

Tribological testing of commercial CrN, (Ti,Al)N and CrC/C PVD coatings — Evaluation of galling and wear characteristics against different high strength steels

The increasing use of high strength steels in a variety of mechanical engineering applications has illuminated problems associated with galling in sheet metal forming operations. Galling is a tribological phenomenon associated with transfer of material from the steel sheet to the tool surface during forming resulting in seizure of the tool/steel sheet contact and extensive scratching of the steel sheet surface. As a result, a number of concepts have been developed in order to reduce the tendency of galling in sheet metal forming, including the development of new dry lubricants, new forming tool steel grades and improved surface engineering treatments such as the deposition of low friction CVD- and PVD-coatings. In the present study the potential performance of three commercial PVD coatings, including CrN, (Ti,Al)N and a CrC/C DLC-based coating, in the forming of hot and cold rolled high strength steel as well as electro and hot-dip galvanized high strength steel has been evaluated using pin-on-disc testing under lubricated contact conditions. Post-test examination of the tribosurfaces using FEG-SEM and EDS analyses was performed in order to evaluate the mechanisms controlling the tendency to material transfer and wear. The results show that in contact with the hot and cold rolled steel the material pick-up tendency of the PVD coatings tend to increase in the order CrC/C-CrN-(Ti,Al)N while in contact with the two galvanized steel sheets, the CrC/C and the (Ti,Al)N coating show a significantly lower material pick-up tendency as compared with the CrN coating. Further, the substrate hardness has a strong influence on the wear of the PVD coatings and consequently on the friction characteristics and galling tendency of the coating/substrate composite. Low substrate hardness, resulting in a low load bearing capacity, increases the tendency to cracking and subsequently chipping of the brittle coating.     

提高渗碳钢多冲接触疲劳抗力的研究

研究了渗碳钢20CrMo表面滚压强化工艺,结果表明,钢渗碳、淬火、低温回火后进行滚压,具有高的多冲接触疲劳抗力,在一定深度范围内,多冲接触疲劳抗力随滚压层深的增加而提高.     

Contact resistance between roll and titanium sheet during cold rolling

In metal forming processes, electrical contact resistance between the workpiece and a tool could give useful information on the contact state of the two surfaces. However, measurement during rolling is difficult because rolls rotate at high speed. In this study, two titanium sheets were cold-rolled in parallel. A closed circuit was composed of the two sheets, one roll and a power source. Difference in electrical potentials between the two sheets was measured to estimate the contact resistance. It is found that the contact resistance decreases with reduction in thickness and that it depends on lubrication and surface conditions of the rolls.     

半固态60Si2Mn直接轧制成形技术的研究

利用自行研制的高熔点半固态金属材料的轧制设备，对60Si2Mn弹簧钢进行半固态直接轧制成形，并研究流变行为和规律，探索出适合于半固态钢铁材料直接轧制成形的生产工艺。研究结果表明：固－液两相的塑性变形行为是不同的，从而导致了轧制产品的心部和边部在组织及性能上的差异。在变形过程中，大多数的固相集中在试样的心部，而液相则流向轧件的边部。随着固相率的提高，固相颗粒发生塑性变形的程度亦提高。若半固态浆料中液相含量过少或变形速率过大，轧辊表面与轧件的温差过大，则轧件的表面会产生微小的裂纹。     

Improved Fracture Toughness of Cryorolled and Room Temperature Rolled 6082 Al Alloys

In the present work,6082 Al alloy has been rolled to 40% and 70% thickness reductions at the cryogenic and room temperatures for the improvement in mechanical and fracture toughness properties.All cryorolled samples are subjected to aging at different temperatures,i.e.,140,160,and 190 °C to improve the strength,ductility,and fracture toughness.The microstructures of the cryorolled(CR) and room temperature rolled(RTR) alloy after 40% and 70%thickness reductions are characterized by FE-SEM to reveal the modes of failure.The results show that the starting bulk Al alloy specimen is fractured in total ductile manner,consisting of well-developed dimples over the entire surface.The mechanical properties and fracture toughness of the 70% CR alloy are found better than 70% RTR alloy due to higher dislocations density and formation of sub-grain structures in the CR alloy.     

表面微坑对轴承振动的影响

以6308轴承为例,用完全数值解法研究了表面微坑对滚动轴承振动的影响,分析了接触位移、接触振动速度、加速度随工况参数的变化.结果表明,对于表面微坑引起的接触振动,速度型检测与加速度型检测具有相同的效果;随载荷的增大、转速的降低,振动加速度增大,在微坑的边缘引起两个接触振动响应,并且这两个响应强度不一样;表面微坑的形状对接触振动有影响,微坑的斜率越大,则其引起的接触振动越剧烈.     

适用于铝合金板材成形的无压痕弯曲模具设计

铝合金板材在弯曲成形过程中,使用传统的折弯模具很难满足零件表面质量的设计要求。本文通过研究铝合金材料的成形特点和折弯模具的工作原理,将折弯过程中的滑动摩擦改为滚动摩擦,设计适用于铝合金板材折弯成形的无压痕弯曲模具,满足零件表面质量要求。     

浅谈轧辊使用技术

介绍了轧辊使用技术对提高轧材质量和延长轧辊使用寿命的主要影响 ,以及轧辊使用技术与促进新材质轧辊应用的关系 ,并对轧辊使用技术的形成、特点、主要内容、作用及发展方向等进行了阐述     

静压支承轧辊轧机支承辊底座的稳定性分析

介绍了一种新型轧机，它依靠由弹性流体动压油膜支承的支承辊来提供轧制力，克服了传统轧机在进行轧制时难以克服的板凸度问题，这对于提高产品的质量以及整个轧辊轧机的工作性能是有益的。在以上优点被证实的同时，进一步对其支承辊底座的稳定性进行探究，用能量稳定法证实了支承辊底座具有稳定性。