现代汽车板材的有铆钉塑性连接及其核心技术探讨

近些年,很多轻质材料如铝合金、镁合金等在现代汽车板材上得到了广泛应用。有铆钉塑性连接在轻质材料的连接上具有巨大优势。本文首先介绍了现代汽车板材有铆钉塑性连接方式及其机制,并对有铆钉塑性连接和点焊等连接方式进行了对比。分析了现代汽车板材有铆钉塑性连接的关键技术。有铆钉塑性连接的关键技术包括铆钉形状、塑性变形程度、板材表面状况、塑性变形速率和加热处理。     

多层板高性能冲铆连接及铆钉形状合理性探讨

简述了现代工业对轻量化板材需求的迫切性,分析了多层轻量化板材连接的传统工艺存在的不足,阐述了多层板材塑性变形连接方式中有铆钉和无铆钉两种工艺的原理和工艺过程、优缺点.主要论述了有铆钉的冲铆塑性连接工艺的发展历程、应用领域、塑性连接机理和材料塑性流动行为.重点研究了铆钉形状为杯型、软与硬圆柱型、腰鼓型、尖头螺钉刺穿型等的...     

对称腰鼓式铆钉实现两层板材锁铆塑性连接特性研究

本文简述了现代工业对轻量化板材需求的迫切性,分析了多层轻量化板材连接的传统工艺存在的不足,简要分析了采用杯形刺入式的铆钉实现两层板材塑性变形连接的工艺过程及其存在的不足。提出了对称腰鼓形的铆钉实现轻量化板材的连接的新方式。明确指出平底腰鼓式对称铆钉连接的主要优势是通过铆钉和压边圈模具几何参数的设计,避免成形板材的下表面凸起、铆钉穿透上板等缺点,与杯形刺入式的铆钉相比较,采用腰鼓式对称圆柱铆钉可以简化送钉系统,降低成本,论述了的铆钉实现两层板材塑性变形连接的工艺工程。平底腰鼓式对称铆钉连接主要技术参数包括铆钉侧面凹槽半径、铆钉侧面凹槽起始高度、铆钉侧面凹槽圆弧倒角、压边圈内径和压边圈倒角的角度。利用Simufact.Forming软件中的机械连接仿真模块,以连接接头的抗拉强度为指标,采用正交试验和有限元分析技术相结合的方法优化模具的几何参数,得到最佳其主要技术参数,仿真结果表明:压边圈内径对抗拉载荷的影响最大,接下来依次是凹槽起始高度、压边圈倒角的角度、凹槽半径和凹槽圆弧倒角,表明腰鼓型铆钉所形成的多层板之间的机械锁很鲜明,从而确保了连接的接头具备优良的抗拉与抗剪强度,接头的连接质量高。     

汽车车身轻量化材料无铆冲压连接技术的研究进展

随着汽车车身多种材料混合应用的发展,轻量化材料的连接面临新的挑战。无铆冲压连接技术以其独特的优势,在金属板材连接领域获得广阔的发展空间。本文介绍了无铆冲压连接技术的特点,分析了无铆冲压连接技术的影响因素和机理,阐述了无铆冲压连接技术的发展,并对无铆冲压连接技术的关键问题进行了重点探讨。最后,指出了无铆冲压连接技术的发展方向。     

自冲铆接头组织及性能分析

分析了有铆自冲铆接和压印连接的工艺特点,对比了两种不同连接方式的接头抗拉伸-抗剪强度;利用阳极化覆膜的方法制备接头金相试样,对接头机械自锁区材料的组织及流向进行观测.结果表明,有铆自冲铆接的抗拉伸-抗剪强度高于压印连接.机械连接导致的材料塑性变形,使晶粒由母材区的等轴状逐渐向纤维状过渡,依据晶粒分布特性,将有铆自冲铆接头截面划分为:母材未变形区、上板内锁区、下板内锁区、上板过渡区、下板过渡区、塑性影响区.在接头自锁区附近由于纤维组织的形成,使金属的性能产生各向异性,沿纤维方向的强度和塑性将高于垂直方向.     

塑性变形对钨铜板材显微结构及性能的影响

研究相对密度92%的熔渗烧结85W-Cu板坯冷轧变形行为.通过对板材中孔洞、钨颗粒变形行为的观测及XRD分析,得出85W-Cu板材的塑性变形机制.孔洞变形、弥合实现材料的致密化,钨颗粒经过纵向移动、横向移动、冷焊、变形过程,钨颗粒断裂贯穿整个塑性变形.材料的致密化和铜相、钨颗粒的变形产生的内应力导致材料显微硬度增加,最后材料失去塑性而失效.在800～930℃温区内对30%～40%变形量板材的退火能够改善材料的塑性.     

摩擦铆压用交流伺服塑性连接设备结构可靠性研究

为了提高低塑性轻量化板材接头的连接质量、降低成形力、避免连接过程中产生裂纹缺陷,提出了摩擦铆压塑性连接工艺,并设计了交流伺服塑性连接设备.利用ANSYS Workbench软件对设备的机身进行了静力学分析,校核了机身刚度和强度,并通过模态分析研究了设备振动响应特性.结果表明:该设备每个自由度的运动均由单独的交流伺服电机...     

轻质板材平底无铆连接成形模具的优化

相较于传统无铆连接,平底无铆连接的主要优势在于通过模具参数设计,避免接头在连接过程中形成凸起,保证接头一侧光滑平整,扩大其在汽车轻量化中的应用。平底无铆连接模具的几何参数主要包括冲头圆角、冲头拔模斜度、压边圈内半径、压边圈圆角和冲压速度。采用正交试验的方法优化了连接模具的几何参数,并通过试验连接板材Al5052对正交试验的结果进行验证。研究结果表明:冲头圆角对互锁值的影响最大,压边圈内半径次之,其次分别是冲头速度、拔模斜度和压边圈圆角半径。在优化的连接模具组合下,对有限元分析和试验结果进行了对比,互锁值的误差为6.1%,颈厚值的误差为8.2%,表明了利用正交试验得到的连接模具可以精确预测平底无铆连接成形过程。     

轻合金热态液力成形技术

铝合金和镁合金等轻合金在常温下变形能力差,但在加热到一定温度时塑性变形能力大幅提高.为了扩大此类轻合金在工业上,特别是在航空、航天以及汽车行业的应用,需要开发先进的温/热态成形技术.本文首先介绍了轻质合金的主要塑性成形方法,如超塑性成形,板材热冲压成形和气胀成形,然后重点讨论了铝合金及镁合金的热态液力成形技术的国内外研究现状,指出了开展此项研究的必要性和重要意义.     

新世纪中国塑性加工行业的发展与展望

进入新世纪以来,在航空、航天、汽车和装备制造等行业的国家重大需求的牵引下,中国塑性加工行业获得快速发展,取得举世瞩目的成绩。根据2000年以来塑性加工行业获得国家技术发明奖和科技进步奖的情况,讨论了汽车覆盖件成形、高性能轻量化构件成形和多工位挤压等塑性加工关键技术的创新与发展,介绍了中国研制的超大型液压成形机、超大型环轧机、360 MN垂直挤压机和120 MN铝合金板材拉伸机等"世界第一"的超大型装备,展望了新世纪塑性加工技术发展趋势,包括:超大尺寸复杂构件塑性成形技术、轻质耐高温材料高性能复杂构件塑性成形技术、非理想材料塑性本构模型与高精度数值模拟、智能化塑性加工装备及生产线。     

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.     

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.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.