PLC控制的焊接工艺对高强钢焊接性能的影响

以厚度为1 mm的冷轧低碳钢板为研究对象,通过PLC控制脉冲频率和占空比等工艺参数,研究了脉冲激光焊接和连续激光焊接条件下,焊接工艺对焊接接头组织和力学性能的影响。结果表明,低碳冷轧钢板适宜的脉冲频率为50 Hz,占空比为30%;连续激光焊接和脉冲激光焊接熔池深度相当的情况下,连续激光焊接的熔池宽度比脉冲激光焊接要宽。     

SiCW/6061Al铝基复合材料激光焊机理

采用脉扩光焊接方法对ＳｉＣＷ／６０６１Ａｌ复合材料进行焊接试验。研究了试件表面处理状态、保护气体、激光输出功率、焊接速度、激光脉冲频率等工艺参数对焊接质量的影响规律。试验结果表明,激光输出功率和焊接速度对焊缝的显微组织和焊接质量都有较大的影响,激光脉冲频率的变化对焊接质量有一定的影响,而试件表面的处理状态对焊接质量影响不大。同时发现,利用Ｎ气代替Ａｒ气也取得了较好的保护效果。利用扫描电镜和岸民镜对     

圆形摆动激光对5A06铝合金激光焊接熔池流动行为的影响分析

摆动激光焊接方法中,激光束对于熔池的搅拌作用将导致熔池流动行为有异于传统激光焊接,因此为了从理论上阐述摆动激光焊接过程中熔池流动行为,构建了5A06铝合金摆动激光焊接过程热—流耦合模型.系统分析了圆摆激光焊接过程中,摆动幅度和摆动频率对熔池热流场的影响规律.结果表明,增加摆动幅度会降低熔池深宽比,从而提高焊接稳定性,同时熔池流动行为更加复杂,增大了熔池内部物质交换范围.摆动频率的增加会抑制熔池流动,使其更加规律,有利于气泡的排出从而降低气孔率.     

动力电池壳体激光焊接工艺

针对动力电池壳、盖激光焊接试验,通过调整激光焊机脉宽、频率、峰值功率等工艺参数,验证不同参数对激光单点能量及焊接平均功率的影响,结合平均功率对焊缝熔深影响及不同熔深状态下与焊缝耐压强度的对应关系,进而优化激光焊接工艺参数,确保动力电池激光焊接过程的稳定性和焊接质量的一致性。     

镁合金脉冲激光焊接温度场的数值模拟

本文采用有限元分析软件Ansys对1．2mm厚度的AZ31镁合金脉冲激光焊接过程进行模拟,通过分别改变激光的脉冲、频率及焊接速度,比较了参数变化对熔池截面形状的影响,确认了该厚度AZ31镁合金板的理想规范参数。研究结果表明：接头熔深随激光脉冲宽度和频率的降低而减小,随焊接速度的减小而增大。激光参数变化对熔池宽度的影响不大。     

超薄紫铜激光焊接工艺研究

针对超薄紫铜片的激光焊接工艺进行研究,分析了激光工艺参数对超薄紫铜片焊接的影响.结果表明,在合适的工艺参数下,超薄紫铜片焊缝成形良好,焊接接头基本与母材等强.对于薄板激光焊接,脉冲工作电流和脉冲频率对焊接成形影响很大.     

超薄不锈钢片激光密封性焊接工艺研究

用波长为1.06μm的Nd:YAG激光器对厚度为0.08 mm的超薄不锈钢片进行激光密封焊接,通过调节脉冲激光的频率、脉宽、焊接速度、离焦量等工艺参数成功地对超薄不锈钢片进行了脉冲激光焊接。本文重点研究了焊接光斑重叠率对焊缝密封性的影响,并详细讨论了影响光斑重叠率的主要因素:脉冲频率、焊接速度、光斑大小之间的关系。     

铝合金中厚板高功率激光搅拌焊气孔缺陷工艺调控

高功率激光焊接为铝合金中厚板高质高效焊接提供了有效手段,然而面临焊缝气孔多发的问题. 文中开展了铝合金中厚板高功率激光搅拌焊接气孔缺陷的工艺调控研究,阐明了搅拌振幅和搅拌频率对接头气孔率的影响,并提出了工艺参数优化方法. 结果表明,搅拌振幅主要影响光束运动轨迹横向分布和小孔开口面积;搅拌频率主要影响激光光束运动速度和对后方熔池的搅拌次数;搅拌振幅和频率越大,气孔抑制效果越明显,但焊缝熔深难以满足应用要求;通过控制光束运动轨迹和能量密度,可以实现工艺参数的设计,获得大熔深、少气孔的最佳工艺区间,最终得到熔深高达6.4 mm的少气孔焊接接头.     

镁合金脉冲激光焊接温度场的数值模拟

采用有限元分析软件Ansys对1.2 mm厚度的AZ31镁合金脉冲激光焊接过程进行模拟,通过分别改变激光的脉冲、频率及焊接速度,比较了参数变化对熔池截面形状的影响,确认了该厚度AZ31镁合金板的理想规范参数.研究结果表明:接头熔深随激光脉冲宽度和频率的降低而减小,随焊接速度的减小而增大.激光参数变化对熔池宽度的影响不大.     

激光增强高压干法水下MIG焊熔滴过渡控制试验

为验证激光对高压干法水下MIG焊电弧稳定性和熔滴过渡控制的影响,搭建了位于高压焊试验舱内的激光增强MIG焊接试验系统,并进行了不同环境压力下激光增强前后的电弧稳定性和熔滴过渡状态对比分析.结果表明,一定功率密度脉冲激光的辅助作用可以克服水下环境压力对熔滴过渡和焊接过程稳定性的负面影响,可以通过脉冲激光控制熔滴尺寸,并且实现熔滴过渡频率与脉冲激光频率保持一致,稳定了焊接电弧,从而提高水下MIG焊过程的稳定性.     

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.