圆形凸台件的冷挤压工艺及模具设计

对圆形凸台件的冷挤压工艺与机械加工工艺进行了比较，对圆形凸台件进行了冷挤压工艺分析，叙述了工艺难点，详细叙述了圆形凸台件冷挤压工艺的工序设计、毛坯计算、毛坯软化处理、凸、凹模的设计及模具整体设计、介绍了圆形凸台件的冷挤压工艺的优越性。     

冷挤压锥形件小端圆柱工艺研究

通过对锥罩圆柱部成形工艺进行分析,采用冷挤压工艺成形该零件圆柱部,并进行了工艺计算;介绍了冷挤压圆柱模的结构及工作过程,并给出了冷挤压凹模和凸模的设计方法;该工艺保证了该零件圆柱部冷挤压成形的顺利进行.     

气门顶杆冷挤压模设计

介绍了气门顶杆冷挤压成形工艺,计算了毛坯尺寸、挤压件的变形程度,论述了冷挤压模结构及模具设计要点。采用冷挤压加工工艺后,提高了零件精度和表面质量,改善了零件的力学性能,显著降低了材料消耗。     

《冷挤压模具设计与制造》讲座(连载十一)

第4讲冷挤压工艺分析及制定4.4冷挤压工艺计算实例4.4.1汽车活塞销汽车活塞销如图4-20所示,材料为20钢或20Cr,这里主要讨论活塞销冷挤压的工艺方案。(1)冷挤压工艺方案的拟定。首先要把活塞销零件图变成适合于冷挤压工艺的冷挤压件图。活塞销     

底螺冷挤压工艺及模具设计

通过对底螺零件的加工工艺进行了分析,介绍了底螺冷挤压模具结构及工作过程,并进行了工艺计算,提出了冷挤压凹模和凸模的设计方法,保证了底螺冷挤压成形的顺利进行。     

阶梯方铝罩挤压成形工艺与模具设计

叙述了冷挤压的工艺特点,对纯铝阶梯方铝罩的加工进行了工艺分析,计算了挤压力并选择了压力机,阐述了冷挤压模具结构及设计要点。     

钛合金六角法兰面自锁螺母的冷挤压工艺及模具设计

详细介绍了钛合金六角法兰面自锁螺母用冷挤工艺代替热镦加工方法的优点.对钛合金六角法兰面自锁螺母进行了工艺分析、制订了冷挤压工艺路线、计算了毛坯尺寸及冷挤压力.根据实践经验总结了毛坯的制备处理、冷挤压模具结构设计及加工技术要求.     

硬铝主动轮冷挤压及精推挤成形工艺

对硬铝主动轮的冷挤压工艺进行分析,确定了冷挤压零件图和冷挤压方案及毛坯尺寸,对零件冷挤压的变形程度进行了校核,计算了挤压吨位,拟定了挤压前的毛坯处理规范,并对模具结构进行了介绍。     

螺塞毛坯冷挤压工艺与模具设计

介绍了采用冷挤压工艺生产螺塞毛坯的特点,并对螺塞毛坯冷挤压工艺进行了分析,计算了坯料尺寸及挤压力,还介绍了毛坯润滑处理方法与挤压模具结构。     

曲柄冷挤压工艺及模具设计

针对曲柄制件,指出了制件的结构特点,分析了制件的成形工艺并介绍了各种成形工艺特点,指出了采用冷挤压工艺成形该制件,并进行了工艺计算,设计了曲柄冷挤压模,介绍了模具结构特点及模具主要工作部分零件设计。     

定位偏心轴冷温挤压成形工艺及模具

分析了定位偏心轴的形状特点,针对冷、温挤压各自的特点,采用两者相结合的成形工艺方案.制定了零件挤压成形图,确定了挤压工艺路线.校核了各道挤压工序的变形程度,同时介绍了冷温挤压模具.指出对于一些尺寸精度高、变形程度较大的零件,可采用冷、温挤压相结合的工艺进行成形;同时,在温挤压前,要预先合理地分配材料,以保证零件充分成形.考虑到坯料在温挤压时受到多种因素的影响,可采用冷推挤工序来确保零件关键部位的尺寸精度.     

Squeeze casting of aluminium alloys for higher formability in cold forging

Abstract

This research project investigated the process conditions of using squeeze casting process to produce aluminium alloy preforms or billets for subsequent cold forging process. The comparative effects of heat treatments, their microstructures and mechanical properties were evaluated. Through these studies and experiments, the main emphasis is on the study of commercial material Al 6061, Al 2014 and Al 356 alloys. The formability of the alloys was carried out using forward and backward extrusion test at 50% area reduction at room temperature (cold extrusion). It was found that when wrought aluminium 6061, 2014 and 356 alloys were squeeze cast to form the preforms, the preform microstructures revealed very fine microstructures that are feasible to be cold extruded. In addition, after thermal annealing treatment of 6061 squeeze cast preforms, the samples showed a similar value of work hardening exponent value of 0˙20 as compared to the wrought aluminium alloy 6061, with a workhardening exponent value of 0˙21 obtained from the static compression test. Wrought aluminium alloys generally cost twice the amount as compared with casting ingots. The microstructures of the squeeze cast 6061 alloy showed no visible cracks or inclusions after the deformation by extrusion. The results of the studies showed that Al 6061 preforms via squeeze cast technique may be cold extruded or formed, which provide an alternative means for the production of billets for the cold extrusion or forging process.     

Cold repeated forming of compact for aluminium foam

A cold repeated forming process of compacts for producing metal foams was developed in order to strongly bond powder particles. In this process, the compact undergoes severe plastic deformation for the strong bonding of particles by repeated backward extrusion and cup compression, and thus the compact largely foams owing to the accumulation of gas released from blowing agents inside the compact during heating. The cold repeated forming process without heating is much simpler than that for the conventional hot extrusion process. The relative density of the foam was decreased by adding silicon powder to the compact, and an aluminium foam having a relative density of 0.27 was obtained using two repeats of backward extrusion and cup compression, 1.5 mass% titanium hydride powder and 4 mass% silicon powder. In addition, a one-piece foam was successively produced from the bonding of two compacts during the foaming in a die. It was found that the cold repeated forming of compacts is effective for the production of metal foams.     

台阶内花键套筒冷挤压工艺研究

分析了台阶内花键套筒的冷挤压工艺 ,制定出冷挤压件图 ,确定了挤压方案及工艺流程 ,对各工序变形程度进行了校核 ,并计算出了挤压力,同时对挤压模具的设计制造进行了简单的介绍。     

Solid-state recycling of aluminium alloy swarf through cold profile extrusion and cold rolling

In this study, the possibility of solid-state recycling of aluminium alloy machining swarf using cold extrusion and a subsequent cold rolling process is investigated. Cast Al-Si alloy swarf was cold compacted into billets and successfully profile-extruded into square bars with a rectangular cross-sectional aspect ratio of 1:1.8 under an extrusion ratio of 4 or more. After annealing, the extruded bars underwent multi-pass cold rolling into 1-mm thick strips with a total rolling reduction of 85%. Optical microscopy demonstrated that in material recycled using only an extrusion process, coarse residual voids existed in regions where insufficient plastic strain was introduced, causing a visible expansion of the material during heat treatment. However, uniaxial tensile tests showed that extrusion-recycled material had a higher mechanical strength than the original aluminium alloy, implying sufficient bonding among the individual pieces of machining swarf. It was also found that the strength and density of material recycled through extrusion and an additional rolling process were superior to material recycled using extrusion only. Moreover, it was observed that the ductility of the recycled materials was inferior to that of the original aluminium alloy.     

局部加载控制不均匀变形与精确塑性成形研究进展

局部加载控制不均匀变形与精确塑性成形关键理论与技术研究,既是先进塑性成形学科前沿领域中的关键和挑战性课题,又是航空航天高技术发展的迫切需求。文章以局部不均匀加载实现通常极难的板面内弯曲成形为切入点,发展了控制不均匀变形以实现精确塑性成形的理论与技术,为我国先进飞机发展面临的大型复杂整体钛框成形制造难题的解决,提供了启示。建立了薄壁管数控弯曲失稳起皱、回弹、截面畸变预测和成形极限分析的模型、过程仿真和优化设计的方法;揭示了其关键影响因素和影响规律;实现了难度很大的薄壁管小弯曲半径数控弯曲精确成形。建立了多道次普旋、曲母线和带内筋件强旋等复杂过程三维仿真模型,提出了解决不均匀变形导致的复杂成形缺陷和旋轮轨迹优化设计难题的方法。解决了大型铝型材先进等温挤压中迫切需要解决的多场耦合作用下温度与速度效应和控制的重大难题。发展了复杂环件辗扩过程和控制仿真的三维有限元模型以及临界摩擦系数确定的解析-数值方法;总结了冷辗扩3种塑性变形行为及多因素耦合对辗扩过程的影响;提出了率相关晶体塑性模型在有限元中实现的稳健算法,实现了冷辗扩宏观变形行为的细观响应描述。     

自行车辐条条母用超高强铝合金工艺研究

对超高强铝合金熔铸、挤压、热处理制度和冷变形量进行试验研究，选择较佳的工艺条件，生产出强度高和尺寸精度好的冷拉线材，满足了用户的使用要求。     

摩托车启动主动齿轮的精密成形

通过合理分配变形程度、控制金属流动，设计出精密成形工艺的合理中间预制坯，并采用温锻制坯与冷挤压相结合的复合成形工艺，成功地进行了启动主动齿轮精锻件的生产。精锻件不仅表面光洁、尺寸精度高、外表面的后续加工余量小，而且冷挤压成形的锯齿状内齿无需后续加工就可以装配使用。因此，精密成形具有显著的节能、节材效果，经济效益十分显著。     

铝及铝合金型材等温挤压关键技术研究进展

介绍了等温挤压工艺的原理及优点,分析了铝型材挤压过程中的热量变化,指出了挤压制品出口温度的影响因素,并以此为基础介绍了实现铝型材等温挤压工艺的几种方法,包括先进的铝型材挤压技术——温度和速度闭环控制的等温挤压原理及实现方法。