基于现场总线技术的VPPA焊接电源网络控制

使用MSP430单片机和端子式总线系统开发变极性等离子焊接电源的DeviceNet现场总线接口,以IGM机器人作为现场总线主站,制定机器人与变极性等离子焊接电源通信的上下行数据协议,成功实现IGM焊接机器人系统通过现场总线对变极性等离子焊接电源的控制。     

DeviceNet现场总线技术在钢圈焊接专机中的应用

笔者研制的GQH-S-DN型钢圈环缝双焊枪自动焊接专机,采用DeviceNet现场总线技术,大幅提高了焊接专机的自动化程度。其不仅使钢圈焊接的双焊枪同时施焊得以实现,而且提高了时间控制精度,使钢圈分段焊接精确度得到保障,提高了工作效率和焊缝质量,该专机是具有较高科技水平的钢圈焊接专用设备。     

基于现场总线技术的变极性等离子弧焊接控制系统

以嵌入式PC和德国倍福E-bus模块组成硬件平台,构建了一套基于现场总线的变极性等离子弧自动化焊接控制系统.利用EtherCAT协议构建系统的运动控制平台,建立空间笛卡儿三维坐标系,采用G代码命令编程,实现对于焊接空间轨迹的示教功能,同时利用DeviceNet协议构建系统的焊接工艺控制平台,建立变极性等离子焊接电源、等...     

现场总线在焊接自动化中的应用

介绍了现场总线的概念和发展趋势,阐述了几种主要现场总线的体系结构和技术特点,分析了现场总线的网络通信与现场总线控制系统基本结构,提出了基本现场总线的焊接过程质量控制集成模型,为最终实现焊接生产单元制造的智能集成提供了技术基础.     

基于DeviceNet总线的双钨极堆焊系统设计及工艺性验证

依据某核电与石化产品堆焊的主要特点与工艺流程,设计了基于DeviceNet总线的高性能PLC控制核心,并配备DeviceNet总线焊接电源、双钨极焊枪、触摸屏、伺服定位系统、弧压处理系统、自动焊接三维滑架等单元构成的双钨极堆焊成套设备。经过焊接工艺试验,验证了整套系统的可靠性、自动化程度、抗干扰能力、扩展性。焊缝成型良好,堆焊效率较单钨极提高1倍,UT探伤、焊缝化学成分、铁素体含量、弯曲性能、晶间腐蚀、硬度等检测项均合格。     

基于CANopen现场总线的分布式控制及应用

基于STM32F103VET6微控制器设计了嵌入式CANopen现场总线设备的硬件。移植了Can Festival进行标准CANopen协议的开发。将研发的分布式焊接控制系统在脉动送气焊接工艺的气体配送中进行了验证,证明了基于CANopen现场总线分布式结构设计的控制系统在实际应用中的实时性和有效性。     

北京石油化工学院能源工程先进连接技术研究中心成果简介（2）——先进焊接自动化技术

文章第一部分介绍了能源工程先进连接技术研究中心水下连接技术成果,本文介绍该研究中心在焊接自动化方面的成果。双车双丝管道焊接工作站采用现场总线技术进行总体设计,焊接电源和焊接小车作为从站与主控单元主站连接,焊接过程可以通过网络接口由上层计算机进行监督。焊接小车采用紧凑式结构,尺寸小重量轻,适合于管道铺设现场应用。工作站采用双车双丝布置方式,结合窄坡口焊接工艺,实现了管道铺设的优质高效焊接,管道焊缝达到API STD1104--2005标准的要求,并成功地进行了海上试验。     

深水海底管道铺设焊接系统设计

为了满足南海深水油气田开发的需要,研制了以焊接工作站为核心的深水海底管道铺设焊接系统。焊接工作站配备2套独立的双炬焊接系统,焊接小车外形尺寸小、质量轻,特别适合于海管铺设工程应用。焊接工作站控制系统采用CANOpen现场总线和网络技术,不仅增加了系统柔性和可靠性,而且实现了现场焊接设备的远程监督。     

基于CAN总线的点焊多机质量控制系统研究

在重要零件的点焊过程中,实时采集焊接现场状态参数并进行质量模糊判别,能够对焊接质量提供进一步的保证.本系统利用数据库技术提供参考参数,利用模糊推理技术为焊后焊点提供焊后质量参考并分析产生不合格焊点的原因,利用现场总线(CAN总线)作为通信媒介,同时管理多台焊机,建立了电阻点焊多机在线质量管理监控系统.此系统不仅直观地提供焊后各台焊机的焊后质量状况,而且调整并存储不同环境下的实际焊接参数,方便技术人员利用历史数据进行分析.     

基于CAN总线的气压焊油泵控制系统

CAN总线,即控制域局域网,为两线制串行总线,具有可靠的错误处理机制,很好的实时性和较强的抗干扰能力,非常适合在恶劣的条件下使用。针对钢轨气压焊现场焊接出现的问题,提出了基于CAN总线解决气压焊油泵控制系统现场应用问题的方案。研制了基于AT89S52单片机、SJA1000、82C250的CAN总线控制器,采用周立功公司的ICAN系列工业模块采集焊接过程中的油压等各种参数,并且通过CAN总线将数据发回总线控制器。总线控制器根据检测回来的参数进行运算和判断,针对不同的运算结果发送相应的命令帧控制ICAN模块动作,从而实现了焊接过程中压力大小和油压方向的控制。     

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.     

Thermodynamics Study on the Decomposition of Chromite with KOH

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.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

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.     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

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.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

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.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

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.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

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.