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目的 分析Al/Cu双金属管在内旋压增量成形时应力、应变、剪切结合强度的分布情况,研究主要工艺参数对双金属管剪切结合强度的影响规律。方法 基于有限元模拟软件,对Al/Cu双金属管内旋压成形过程进行有限元数值模拟;研究了内旋压增量成形时工艺参数:内管减薄率ψ、两管之间的初始间隙c、旋轮进给比f对剪切结合强度的影响。结果 随着工艺参数内管减薄率ψ、两管之间的初始间隙c、旋轮进给比f的增大,剪切应力数值也随着增大;基管与衬管的高剪切应力值主要集中在旋压结束部分,衬管的长度被拉长,模拟与实验的剪切应力在旋压成形的末端数值明显增大。结论通过有限元数值模拟分析,得出不同的工艺参数对成形质量的影响规律,对实际成形有重要的作用。 相似文献
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为解决弹体旋压生产中参数难以选择的问题,基于弹塑性有限元基本理论,综合考虑旋压过程中金属在3个方向的流动以及摩擦等实际情况,建立了某导弹弹体某舱段旋压加工的三维弹塑性有限元力学数值模型,研究了几种关键工艺参数(包括旋轮圆角半径、进给速度、每道次减薄率等)对旋压成形结果的影响规律。 相似文献
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三旋轮缩旋时金属变形规律研究 总被引:2,自引:0,他引:2
利用三旋轮自动错距旋压机对管坯进行缩旋成形实验,分别研究了缩径量和旋压道次等工艺参数对缩旋成形的影响规律,并探讨了其变形机理,结果表明,三旋轮缩旋时变形区坯料的壁厚减薄,轴向长度增加,壁厚减薄量与总的缩径量成正比,在缩径量相同的条件下,旋压道次增多,坯料壁厚减薄的程度也增大。 相似文献
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目的研究工艺参数对高温合金Ω截面密封环旋压成形过程的影响规律,解决该类构件旋压成形难题。方法基于ABAQUS/Explicit平台建立了高温合金Ω截面密封环普旋三维有限元模型,通过该模型研究了旋压成形过程中的主要工艺参数对其等效应力、等效塑性应变、壁厚变化的影响规律,进而揭示了各参数对环件成形质量的影响。结果芯模转速增大,不均匀变形程度增大,等效应力峰值先增大后减小,壁厚减薄基本不变;增大旋轮进给率与旋轮圆角半径,均有利于降低不均匀变形程度和等效应力峰值,改善壁厚减薄。结论当芯模转速为10~15rad/s,旋轮进给率为0.8~1.0mm/r,旋轮圆角半径为1.5~2.0 mm时,可以获得成形质量较高的Ω截面密封环。 相似文献
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工艺参数对剪切旋压旋压力和壁厚差的影响 总被引:3,自引:0,他引:3
在锥形件剪切(变薄)旋压过程中,旋压力分析对于确定工艺参数及设备选型都具有重要意义,而壁厚差是衡量旋压件成形质量的关键指标之一.基于ABAQUS/Explicit平台建立了锥形件剪切旋压的三维有限元模型,进而获得了偏离率、旋轮圆角半径、旋轮进给量、芯模转速及旋轮直径对LY12M锥形件剪切旋压旋压力和壁厚差的影响规律.研究表明:旋压力随偏离率增加而减小,随旋轮圆角半径、旋轮进给量、芯模转速的增加均呈上升变化趋势;偏离正弦律的程度越大,壁厚差越大;旋轮圆角半径为毛坯厚度的1~2倍,壁厚差较小;较大的旋轮进给量和芯模转速有利于减小壁厚差.旋轮直径对旋压力和壁厚差的影响不显著. 相似文献
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Y型三通管内高压成形壁厚分布规律 总被引:1,自引:1,他引:0
为了解Y型三通管内高压成形时的壁厚分布及成形压力对壁厚的影响规律,通过数值模拟和实验对Y型三通管的内高压成形过程进行了研究,分析了3个不同成形阶段零件的壁厚分布规律和成形过程中零件典型点壁厚随内压的变化规律.研究表明,成形后零件左侧过渡区圆角处壁厚最大,右侧过渡区圆角处次之,枝管顶部壁厚最薄.利用数值模拟,研究了不同终成形压力对零件壁厚分布的影响,研究发现随着终成形压力的提高,零件的最大增厚率变化不明显,但零件的最大减薄率有显著的增加. 相似文献
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Goutam Mukhopadhyay Sandip Bhattacharyya 《Journal of Failure Analysis and Prevention》2013,13(4):474-482
The failure analysis on the premature wear of a “Laying Head Pipe” in a Wire Rod Mill has been presented. The hot-rolled wire rods subsequent to finish rolling pass through the “Laying Head Pipe” which rotates and lays the wire rods in the form of coils for air cooling to achieve the final properties. A worn-out pipe and a thermo-mechanically treated (TMT) re-bar have been analyzed. The material of the pipe is ASTM A335-P5 grade of seamless alloy steel pipe used for high temperature service. The microstructures of the wear groove of the alloy steel pipe show predominantly ferrite and globular cementite/carbide particles along with scales, while that away from the wear groove shows coarse tempered martensite matrix. EDS analysis confirms the presence of alloy carbides near the wear groove. Microhardness profile shows reduction in hardness toward the inner surface of pipe; hardness at the inner surface of the pipe becomes lower than the surface hardness of the TMT re-bar, exhibiting tempered martensite matrix. Softening at the inner surface of the pipe wall occurs due to a rise in temperature/ over-tempering in contact with the passing hot wire rods (900 °C) which causes transformation of martensite into ferrite and coarse globular cementite. 相似文献
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Metal sheet spinning is an advanced near-net forming technology for the manufacture of thin-walled ellipsoidal heads. The exact control of dimensional accuracy, however, is a considerable problem for spinning thinwalled parts with large diameter-to-thickness ratios. In this work, a marginal-restraint mandrel-free spinning process with two passes is proposed for the fabrication of thinwalled ellipsoidal heads without wrinkling. A finite element model is established and verified to study the influences of spinning parameters on the dimensional precision of thin-walled ellipsoidal heads. It is found that the spinning parameters considerably influence the deviations of wall thickness and contour characteristics. A small forming angle or small roller fillet radius during the first pass spinning, as well as the small angle between passes or high feed ratio during the second pass spinning, can improve the wall thickness precision. Meanwhile, as the forming angle or feed ratio is increased during the first pass spinning, the contour precision initially increases and then decreases. During the second pass spinning, the contour precision can be improved at a small angle between passes, whereas it deteriorates at a larger roller installation angle. The optimized spinning parameters are obtained and verified by experiments.The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-020-00296-0 相似文献
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Marginal-restraint mandrel-free spinning is an advanced technology for manufacturing ellipsoidal heads with large diameter-thickness ratios. The effects of spinning parameters on the forming accuracy of ellipsoidal heads have been studied, and optimized spinning parameters have been obtained. The microstructure evolution of a workpiece is usually very complicated in the spinning process. In this work, the influence of spinning parameters on the microstructures of two-pass spun ellipsoidal heads is studied. It is found that the forming angle and feed rate of the first pass, angle between passes, and feed rate of the second pass significantly affect the microstructures. Meanwhile, the evolution rule of the microstructures near the inner and outer surfaces of the spun parts is almost consistent. A large forming angle, large angle between passes, or large feed rate of the second pass are beneficial to obtain uniform microstructures. A small or large feed rate of the first pass reduces the microstructure uniformity. To improve the microstructure uniformity between the inner and outer surfaces, the optimized spinning parameters are determined.The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-020-00322-1 相似文献
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The high-speed drawing of high carbon content steel wires is usually conducted at room temperature employing a number of passes or reductions through several dies. In the multipass drawing process, the temperature rise at each pass affects the mechanical properties of the final product (such as its bending and torsion properties, and its tensile strength). This temperature rise during deformation encourages delamination in the wire, which has a deleterious influence on the torsional properties and durability of the wire. In this study, we investigated the delamination of wires using torsion tests and evaluated the wire temperature during drawing. Our data shows that one of the main reasons for delamination was an excessive rise in wire temperature. Based on our experimental results, in order to prevent delamination due to an excessive rise in wire temperature, a new isothermal pass schedule that could control the wire temperature was designed. The pass redesign for the conventional high carbon (0.75 wt%C) steel cord wire drawing process with delamination was carried out by using the isothermal pass schedule to control the wire temperature. In order to verify the effectiveness of the proposed method, wire drawing and torsion test were conducted. From the results of experiments, it was possible to produce high carbon steel cord wire without delamination. 相似文献
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利用木材苯酚液化物合成纺丝液, 熔融纺丝制成新的炭纤维原丝, 研究了纺丝液合成因素对原丝性能的影响。试验结果表明: 增加合成纺丝液时液化原料中的苯酚/木材比(液固比), 则原丝的力学性能提高明显, 其中液固比由3增加至4时, 原丝拉伸强度增加了近9倍; 合成剂用量的增加却导致原丝力学性能的降低, 当合成剂用量为6%时, 原丝的拉伸强度和拉伸模量降幅较明显, 而断裂伸长率的最大降幅却出现在合成剂用量为4%时; 原丝的拉伸强度和拉伸模量随合成温度的升高而增加, 但增幅较小, 断裂伸长率随合成温度的升高却呈下降趋势, 且从110℃升高到115℃时断裂伸长率降幅较大; 原丝的力学性能随合成纺丝液升温时间的增加而先升高后降低, 升温时间为40min时制备的炭纤维原丝的力学性能最优。 相似文献
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In this study, an attempt is made to improve the energy and exergy performance of solar air heater by employing double pass with different absorber surface geometries (roughened, finned, and v-corrugated wire mesh) in the second pass, and also by mounting longitudinal fins in the back side of the absorber plate (first pass). The effect of varied mass flow rate and solar intensity on temperature rise of air, energy efficiency, exergy gain and pressure drop at steady state condition was determined for different types of solar air heaters utilizing an indoor solar simulator. The temperature rise of air, thermal efficiency and exergy gain depends on mass flow rate, surface geometries of absorber and solar intensity, whereas the pressure drop depends on mass flow rate and surface geometries of absorber. 相似文献