成形加强筋工艺研究与模具设计

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。     

后侧门内板锁孔附近起皱缩颈开裂的解决方法

针对汽车后侧门内板在成形过程中锁孔附近产生起皱开裂的问题,分析了起皱开裂产生的原因,起皱区域需局部增加板料成形或减少板料流动,缩颈开裂区域需局部减少板料成形或增加板料流动。采用四象限分析法,采取增大R角或拔模角度、调整废料区刺破刀、加高法兰边工艺补充、提高模具零件表面粗糙度和硬度、控制板料油膜厚度、调整气垫压力、将凹模、凸模和压边圈镀铬等措施,使起皱和缩颈开裂缺陷得到有效控制,提高模具生产稳定性。     

汽车前门铰链成形质量分析及实验研究

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.     

扇形加强筋结构对汽车后轮毂包成形质量的影响

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。     

后门外板B柱区域冲压起皱分析及优化

对于主棱线圆角半径为2.5 mm且圆角两侧曲面夹角较小的汽车后门外板,采用传统冲压工艺时,后门外板B柱区域会产生严重的起皱缺陷,无法满足外观质量要求;通过数值模拟,对零件成形过程和缺陷区域的应力状态进行分析,阐明了缺陷产生的原因,并提出优化工艺方案,消除了零件成形时的缺陷;经生产验证,该工艺可有效解决后门外板B柱区域的起皱现象,为解决类似零件的冲压缺陷提供参考。     

侧围外板门洞起皱的解决措施

针对侧围外板门洞褶皱产生的原因进行分析,通过CAE软件模拟验证零件成形工艺更改方案并在模具上实施整改,最终消除缺陷,从零件、工艺、调试等方面总结了有关门洞起皱问题的解决措施。     

乘用车地板通道零件回弹及起皱特性分析

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。     

变截面型材拉弯成形工艺仿真与优化

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。     

不压边冲压球、锥面零件的成形极限

<正> 一、前言 在冲压生产中加工球面或锥面零件的工艺方法有两种形式:用带压边装置的模具成形和用不带压边装置的模具成形。采用不带压边装置的成形方法具有模具简单、加工方便、不要求使用复杂的双动压力机或带气垫的压力机、成本低等优点。选取冲模的型式,主要以毛坯在冲压过程中是否起皱为主     

基于冷冲拉模具设计的DYNAFORM模拟

基于有限元法建立的DYNAFORM用于模拟钣金成形工艺,对拉深、冲压模具的拉深过程进行数值模拟,通过观察零件图、FLD图、零件厚度变化图、零件应变图,预测成形过程中板料的裂纹、起皱、减薄、划痕、回弹、成形刚度和表面质量来获得在拉深过程中的可行性和模具设计的合理性,从而评估板料的成形性能和产生各种缺陷的原因,以及采用的预防措施,为板金成形工艺及模具设计提供技术支持。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

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.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

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.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

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).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

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.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.