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目的 解决多拐曲轴镦挤复合成形过程中,轴向流动导致尺寸精度低的问题。方法 从坯料加热、成形过程、成形后冷却等全流程模拟出发,以建立镦挤成形装置运动学、成形过程热力学、曲轴材料本构模型、几何模型等为基础,建立有限元模型,分析产生轴向偏差的原因。结果 有限元模拟分析表明,坯料体积、飞边厚度是镦挤成形过程产生轴向流动的关键性因素,可以通过优化台阶轴毛坯几何形状,控制轴向异常流动。结论 试验表明,多拐曲轴的轴向流动得到有效控制,单拐轴向长度偏差控制在±1 mm,成品率提高至90%以上。 相似文献
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目的研究坯料形状对汽车空调压缩机双头活塞锻造成形质量的影响,以期提高材料利用率,获得成形质量良好的零件。方法基于有限元数值模拟及物理试验,对不同坯料形状的成形结果进行对比研究,分析坯料形状对成形过程中金属流动行为和成形质量的影响。结果模拟表明成形零件的A和B区域时,载荷缓慢上升,成形零件C区域时载荷急剧升高,圆柱成形载荷为230 t,异形坯成形载荷为180 t。异形坯向零件两端转移了更多的金属,使型腔A和B区域飞边槽内金属体积少于圆柱坯。物理试验表明异形坯成形结果良好。结论通过合理减小坯料长度和宽度、增加坯料高度,使材料利用率提高了7.91%,成形载荷降低了21.7%。 相似文献
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目的坯料的误差是影响冷拔成形精度的随机误差,研究在实际冷拔生产中坯料误差影响的控制方法。方法以冷拔45钢的传动轴为例,利用ANSYS对冷拔过程进行模拟仿真,分析坯料直径误差对冷拔成形精度的影响。结果即使在优化的冷拔预处理工艺和优化的模具结构参数等条件下,坯料的误差对冷拔精度影响较大,难以达到IT7以上的冷拔精度。结论针对这一问题,提出了使用可变径模具来控制冷拔成形尺寸,通过模拟分析比较,证明了调节冷拔模具的直径可以控制冷拔成形尺寸,从而提高冷拔成形精度。 相似文献
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根据某规格汽车轮毂轴管零件的形状尺寸特点,设计了预锻毛坯和2种终锻成形方案,并对所制定的2种终锻方案进行了工艺和模拟分析。2种方案的模拟结果显示,顺序成形过程稳定,变形只局限于端部;一次镦粗变形不局限于变形的端部,在变形结束时有少量金属流入杆部,这将会使端部缺料和杆部出现折叠和缩径缺陷。顺序成形可改善模具的受力状况,成形力有所降低,提高了模具寿命。根据力-行程曲线,应严格控制变形部位金属的体积,实现小飞边精密锻造,避免成形力在成形最后阶段急剧增大,以致损坏模具和设备。 相似文献
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为了提高航空锻件的综合性能,通过等温锻压工艺研究了航空接头锻件的成形过程,采用Deform3D有限元软件对高筋薄壁铝合金航空接头锻件的锻压成形工艺进行了仿真研究,在实验室油压机上开展了缩比(1∶5)锻件的成形工艺实验.研究结果表明:在坯料与模具温度均为450℃、成形速度为0.1 mm/s的等温模锻工艺下,材料变形抗力比常规热模锻降低70%,材料在模腔中的流动性提高,锻件充填完好,锻件变形均匀,应力集中降低;等温锻造工艺可使锻件获得流线顺畅、晶粒细小、力学性能优良的纤维组织,避免了热模锻易出现的涡流、折叠、穿流、充填不满等锻造缺陷;仿真与实验结果吻合,为航空接头锻件锻压成形工艺的制订提供了依据. 相似文献
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目的采用多步辗扩工艺模型虚拟生产异形环件,研究环件多步辗扩过程中环件的成形规律,为实际生产提供工艺参数。方法利用Gleeble-3500D热模拟实验机对Q345E钢进行单道次热压缩实验,建立环件用钢的流变应力模型,在Simufact中建立大型锻坯外凹槽内台阶环件多步辗扩三维数值稳定辗扩模型,对环件辗扩过程进行数值模拟。结果在双件辗扩内台阶环件和外凹槽环件的过程中,在与成形辊的接触部位应变场呈现较大值,环件的温度分布从心部到外逐渐降低,环件的应变与温度分布极为不均匀,辗扩过程需要对芯辊分级降速。结论通过所建立的多步辗扩模型,可以利用矩形锻坯虚拟生产异形环件。 相似文献
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The isothermal forging process of a typical aviation component with complex shape of high ribs and thin webs was simulated based on the finite-element method, aiming to obtain a set of optimal process parameters. According to the simulation results, the aviation component was successfully formed with a good surface quality by the isothermal forging process. Metallographic analysis shows that recrystallization took place all over the cross section of the forging. The grain size of different areas is basically the same. As indicated by the transmission electron microscope micrographs, dislocations at the surface of the forging have almost the same distribution as those at the core, whereas the dislocations at the surface of the billet by hot forging process are much denser than those at the core. Moreover, the precipitates in the forging by the isothermal forging process were basically of the same small size. On the contrary, larger precipitates were formed at the grain boundaries than in the matrix of the billet through the hot forging process. In one word, uniform grain size and homogeneous distribution of dislocations and precipitates were found in the aviation component by the isothermal precise forging process. 相似文献
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目的 某型号不锈钢阀盖是一种典型的长肋条内空型零件,在模锻制造过程中,阀盖锻件容易出现不同程度的折叠和裂纹缺陷,亟需改进成形工艺以提升合格率.方法 采用有限元方法分析坯料在制坯/预锻/终锻全流程的金属流动规律和终锻件成形质量,得到最佳成形工艺方案.结果 方坯在后续成形时易产生横向流动,且局部充型不饱满;六边型坯在预成形和终成形时流动均匀、横向流动小,且有效抑制了充型不饱满缺陷;预制坯在过渡区长度过短,产生了折叠缺陷;采用六边形坯料和增加过渡区长度可以获得无缺陷阀体锻件.结论 采用新工艺制备的阀盖锻件合格率达到了100%,通过全流程工艺分析,能够得到金属流线规律,进而优化模锻成形方案,改善成形质量. 相似文献
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Yuli LIU He YANG Tao GAO Mei ZHAN 《材料科学技术学报》2006,22(4):473-477
Blade precision forging is a high temperature and large plastic deformation process. Process parameters have a great effect on temperature distribution in billet, so in this paper, by taking a Ti-6Al-4V alloy blade with a tenon as an object, the influence of process parameters on the temperature distribution in precision forging process was investigated using 3D coupled thermo-mechanical FEM (finite element method) code developed by the authors. The results obtained illustrate that: (1) the gradient of temperature distribution increases with increasing the deformation degree; (2) with increasing the initial temperature of the billet, the zones of high temperature become larger, and the gradient of temperature distribution hardly has any increase; (3) friction factors have little effect on the distribution of temperature field; (4) with increasing upper die velocity, temperature of the billet increases while the temperature gradient in billet decreases. The results are helpful to the design and optimization of the process parameters in precision forging process of Ti-alloy blade. 相似文献
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Effects of Process Parameters on the Temperature Field in Ti-6A1-4V Alloy Blade Precision Forging Process 总被引:1,自引:0,他引:1
Blade precision forging is a high temperature and large plastic deformation process. Process parameters have a great effect on temperature distribution in billet, so in this paper, by taking a Ti-6Al-4V alloy blade with a tenon as an object, the influence of process parameters on the temperature distribution in precision forging process was investigated using 3D coupled thermo-mechanical FEM (finite element method) code developed by the authors. The results obtained illustrate that: (1) the gradient of temperature distribution increases with increasing the deformation degree; (2) with increasing the initial temperature of the billet, the zones of high temperature become larger, and the gradient of temperature distribution hardly has any increase; (3)friction factors have little effect on the distribution of temperature field; (4) with increasing upper die velocity,temperature of the billet increases while the temperature gradient in billet decreases. The results are helpful to the design and optimization of the process parameters in precision forging process of Ti-alloy blade. 相似文献
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以丁字臂锻件为研究对象,分析其工艺性,基于DEFORM有限元数值模拟软件进行有限元仿真,找出丁字臂成形存在的问题,改进传统工艺方案,优化毛坯.由模拟结果知,只用平砧拔长杆部,拍扁大头部的方案不能得到满意的结果,而在平砧拔长拍扁后增加一道用胎膜拔长中间部分的工序可以获得很好的模拟结果. 相似文献