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针对成形加强筋时产生起皱、翘曲、缩颈、裂纹的缺陷,进行成形加强筋的工艺分析计算,并在实际生产中进行试冲调试,经过批量生产后,总结了不同厚度、不同材料成形加强筋的最佳工艺参数。成形加强筋后,在零件不产生缩颈、裂纹的前提下,加强筋的高度h达到最大值,解决了提高零件刚度与产生裂纹的矛盾。利用成形设备油压机气垫力能够滞后于主缸压力的功能,改进模具结构,在模具结构上采用设备主缸压力压料、气垫反顶成形加强筋的新思路,解决了零件起皱、翘曲的缺陷,大大减少了校平的工作量,取得了较好的效果。 相似文献
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汽车前门铰链成形质量分析及实验研究 总被引:1,自引:1,他引:0
本文以汽车前门铰链加强件零件在成形过程中所产生的破裂、起皱问题为研究对象,通过板料成形分析软件DYNAFORM进行数值模拟.研究了不同的工艺补充和加强筋布置对零件冲压成形的影响.结果显示,采用合理工艺优化能有效地控制破裂、起皱缺陷,从而验证了新方案的合理性和可行性.通过进一步研究不同角度下的加强筋对起皱趋势的影响规律,获得了布置加强筋合理的角度值为10°,使其起皱部分的材料最小变薄率由-5.5%增为15.6%.最终按此优化的型面应用到实际冲压中,成功获得了合格产品. 相似文献
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以汽车后轮毂包零件在成形过程中所产生的起皱问题为研究对象,针对该零件采用传统矩形加强筋结构设计方法上存在的成形工艺缺陷,提出一种新的扇形加强筋结构。通过板料成形分析软件DYNAFORM对新结构方案进行数值模拟,结果显示采用扇形筋明显改善材料的流动方向,有效地控制起皱缺陷,从而验证了新结构方案的合理性和可行性。通过进一步研究不同高度和不同扇形角度下的扇形加强筋对起皱趋势的影响规律,获得了扇形筋合理的高度值5mm和扇形角45°,使其起皱部分的材料最小变薄率由-19.70%增为15.8%。最终按此在实际生产中获得了合格产品。 相似文献
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地板通道零件是乘用车车身骨架中形面复杂的代表性零件,零件冲压成形过程中极易产生回弹与起皱从而影响到零件质量。应用CAE分析软件-Autoform对地板通道零件的板料冲压成形过程中回弹与起皱特性进行分析,得到了最佳的冲压力、冲压速度、压边力及回弹补偿等参数,确定最优工艺参数为:冲压速度5000 mm·s-1,压边力1200 k N、模具拉延筋向外移动4 mm。采用最优工艺参数进行成形工艺试验,试验结果表明,成形零件回弹变形量可以控制在-0.626~0.937 mm之间,同时解决了零件起皱缺陷,获得了质量合格的地板通道零件。 相似文献
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根据7075铝合金变截面缘条零件的特征建立有限元仿真模型,研究变曲率型材成形过程中的各项工艺参数对零件拉弯成形时所产生的起皱和回弹等表面质量问题的影响。在等截面与变截面的不同条件下的拉弯仿真工艺参数的选择,会直接影响成形结果。加大拉紧力,可以有效解决拉弯后零件的起皱现象;在相同拉紧力下,减小型材宽度,可以避免型材断裂的问题。增加包覆角度,可以降低拉弯后零件的回弹量,也可以使零件卸载后的相对于模具的位移缩短。工艺仿真与工艺参数的优化可以解决拉弯后零件的起皱和回弹现象,并通过工艺试验对仿真后的结果进行工艺验证。 相似文献
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以某SUV车型侧围外板零件为例,采用Autoform数值模拟软件对侧围外板零件的结构特点和冲压成形工艺进行分析,重点论述了其流水槽区域、门框区域、后保搭接区域和尾灯区域的冲压成形;预测了可能出现的成形缺陷并制定了合理的冲压工艺方案。分析结果表明,侧围外板流水槽区域、门框的A柱部位、尾灯区域存在起皱现象,后门框的圆角部位和后保搭接区域存在开裂风险;采取加大开裂处的模具圆角、调整压边力和改变加强筋长度等措施,对成形工艺进行了优化。试制结果表明,采用优化后的冲压工艺可以有效预防侧围外板零件的起皱、开裂缺陷。 相似文献
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Deng-Kui Zhang Guo-Qing Wang Ai-Ping Wu Ji-Guo Shan Yue Zhao Tian-Yi Zhao Dan-Yang Meng Jian-Ling Song Zhong-Ping Zhang 《金属学报(英文版)》2019,32(6):684-694
In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone. 相似文献
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After nearly two years'tense construction the first phase of industrialized base of Shenyang Research Institute of Foundry 《中国铸造》2008,5(1):63-64
After nearly two years' tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry (SRIF), located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation. 相似文献
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Z. Sun S.L. Zheng Y. Zhang 《金属学报(英文版)》2007,20(3):187-192
Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process. 相似文献
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R. González-Martínez 《金属学报(英文版)》2007,20(4):235-240
The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke. 相似文献
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The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C). 相似文献
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The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel. 相似文献
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B.W. Zhang B.W. Li 《金属学报(英文版)》2007,20(2):129-138
On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes' collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process. 相似文献
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R.Z. Wu Z.K. Qu B.D. Sun D. Shu J. Wang 《金属学报(英文版)》2007,20(3):193-198
The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results. 相似文献
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This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before. 相似文献
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Chao Yang He-Fei Huang Massey de los Reyes Long Yan Xing-Tai Zhou Tian Xia De-Liang Zhang 《金属学报(英文版)》2015,28(7):809
Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties. 相似文献