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在常温下对T2纯铜坯料进行了扭转挤压成形,运用Deform-3D有限元软件进行了扭转挤压的建模,并对成形过程进行了模拟。分析了不同扭转速度对挤压制品的等效应变和温度的影响。进行了扭转挤压试验,将试验结果和仿真数值进行了对比。结果表明,挤压速度一定(2 mm/s)时,扭转速度对坯料的变形量和挤压温度影响很大;随着扭转速度的增加,坯料的最大应变量变大,晶粒变细。当扭转速度超过2 rad/s和坯料的最大温度大于200℃时,本来细化的晶粒又会再结晶长大。在进行等速挤压且温度没有超过200℃时,可以较大程度地增大扭转速度以细化晶粒。 相似文献
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高温合金穿孔性能的试验研究 总被引:1,自引:1,他引:0
采用热扭转试验和锥形试验的方法对高温合金的穿孔性能进行了试验研究;分析了高温合金穿孔性能的特点,并对几种高温合金的穿孔性能进行了比较。 相似文献
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本文对纳达依(Nadai)表达式作了简单的证明,表明它具有严格性,并非是经验性近似表达式。纳达依表达式应用于圆柱形试样扭转试验测定其真实扭转应力。提出一种测定真实扭转应力的简单方法,即图解法。用铝合金、钢和钛合金进行了测定真实扭转应力试验,对用常规的方法测定的名义扭转应力与用基于纳达依表达式的方法测定的真实扭转应力进行了比较。结果表明,在部分塑性扭转状态下的名义扭转应力高于真实扭转应力。两者相差的数量随塑性扭转部分的扩大而增加。对于所试验的铝合金,其名义扭转应力τ_(p0·015)和τ_(p0·03), 相似文献
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对大规格线材进行扭转试验,通过对试验数据的统计分析,推荐大规格线材扭转试验试样标距采用L0=22d,转速采用2r/min。 相似文献
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针对车用扭杆端头在镦粗加工时,其始锻温度、锻造方式以及锻机进给速度等工艺参数对端头的表面质量影响较大的问题,采用有限元法,建立车用扭杆及端头的有限元模型,利用Deform-3D软件对扭杆及其端头进行网格划分以及边界条件设置,对其镦粗过程进行仿真,考虑了热交换模型,对不同的始锻温度和进给速度下,扭杆端头所产生的轴向应力、轴向应变以及表面损伤进行探究,得出了适用于车用扭杆端头镦粗工艺的相关规律。结果表明:始锻温度在1150~1200℃之间、锻机进给速度为1 mm·s-1时,车用扭杆端头的表面损伤最小,工件性能较好。 相似文献
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对AZ31镁合金挤压棒材在循环扭转变形过程中的力学性能和织构演化进行了研究。循环扭转变形分别在298,373,443,503和573 K下进行。镁合金循环变形的力学性能测试结果表明,循环扭转变形过程的应力应变滞回线呈现严格的对称性,意味着微观变形模式以滑移为主。变形过程的热效应使应力应变曲线中的峰值应力随着周期数的增加而降低。变形过程中柱面滑移系启动使晶粒取向发生改变,由变形前的{11■0}⊥ED织构转变为变形后的{10■0}⊥ED织构,变形过程中拉伸孪晶启动使晶粒取向产生两种变化。 相似文献
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The influence of torsion deformation on textures of cold drawing pearlitic steel wires was investigated by twisting the wires to different number of revolutions. Macro-texture(over the entire wire cross section) associated with torsion deformation was investigated by X-ray diffraction, while micro-texture(near the wire surface) was characterized by EBSD. The results show that the 110macro-texture increases at the beginning of torsion and then decreases with increasing of torsion strain, while the 110 micro-texture decreases linearly with increasing of torsion strain. The relationships between the 110 fiber texture and the microhardness of the wires are also discussed. 相似文献
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Xu Kong Yu-Min Wang Xu Zhang Qing Yang Guo-Xing Zhang Li-Na Yang Rui Yang 《金属学报(英文版)》2019,32(10):1244-1252
The damage behaviors of a titanium matrix composite shaft under torsion loading were monitored using the acoustic emission technique. The composite shaft with SiC fibers at ± 45° orientations was prepared by the solid-state fabrication process. Both the torsional rigidity and torsional strength of the TMC shaft were improved by SiC fibers. The acoustic emission responses during the loading–unloading–reloading, under quasi-static and cyclic torsion tests were investigated. Multiple acoustic emission signals were grouped as mechanical noise, matrix deformation, interface debonding and fiber fracture using amplitude, waveform shape and frequency centroid parameters. A substantial reduction of signals generated by matrix deformation was found in the reloading test. During the quasi-static torsion test, interface debonding and progressive breaks of SiC fibers occurred. According to different acoustic emission behaviors, the failure process in the torsion fatigue test can be divided into three stages: the initial stage, the fiber fracture stage and the fast fracture stage. 相似文献
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Byoung Ho Lee Sun Mi Kim Mohamed El Mehtedi Enrico Evangelista Chong Soo Lee 《Metals and Materials International》2010,16(2):197-203
The influence of stress state on the high temperature workability of rolled AZ31 Mg alloy was investigated on the basis of
a processing map. To construct the processing map, high temperature compression tests were carried out on samples oriented
parallel to the rolling direction at various temperatures (25 °C∼450 °C) and strain rates (10−3 s−1∼5s−1), and then the results were compared with those of a torsion test. The overall efficiency profiles of both the compression
and torsion processing maps were similar to each other, but the index of dissipation efficiency in the torsion was somewhat
lower than that in the compression. The microstructure of the compressed specimens revealed much finer grained structure than
that of the torsion specimens. Such microstructural differences were attributed to the different tendencies of twin formation
and texture evolution depending on the stress state. 相似文献
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针对行星轮系结构复杂,故障信号特征提取困难,提出使用扭振信号对行星齿轮箱故障进行诊断。通过对行星齿轮箱横向振动信号与扭振信号的频谱分析发现,扭振信号相对于往复振动信号更适合行星轮系的故障诊断。针对扭振信号微弱,冲击特性不明显,提出基于最大相关峭度反褶积处理扭振信号。首先对采集的行星齿轮扭振信号先进行零均值化预处理,然后使用MCKD方法增强扭振信号的冲击特性。以故障冲击特性的峭度值作为选择FIR滤波器长度的选择依据,最终使得行星齿轮箱扭振信号的故障冲击特征得到显著提升。该方法对于扭振信号的降噪与提高周期故障冲击特征有效,适用于行星齿轮箱扭振信号的故障诊断。 相似文献