储罐倒装埋弧横焊自动对中装置的研制

设计研制了一种接触式埋弧横焊自动对中装置,用于大型立式储罐倒装法施工罐体横焊缝的焊接.该装置是专门为大型储罐自动焊接研制的,对中精度高,抗干扰能力强,成本低,实用性强,解决了以往储罐倒装自动焊装置人工对中调节不方便,经常出现跑偏等问题.该装置由位移传感器、信号处理器、自动调整机构和钢制柔性跟踪轨道等部分组成.     

大型储罐横焊技术的发展与应用

阐迷了当前我国大型储罐的发展状况,比较了大型储罐目前常用的横焊工艺;论迷了横焊焊接设备的发展和前景,重点阐述了当前应用较普遍的自动横焊机和正在重点研究的移动横焊机器人;论述焊接自动跟踪技术在横焊中的应用和发展,讨论了接触式、激光图像和激光测距传感器等几种常见焊接跟踪传感器.     

储罐倒装埋弧自动横焊机的改进研发

某公司在发展大型储罐倒装法施工技术的过程中遇到难题,由于储罐壁板内侧有顶升液压缸挡着,罐壁内环缝焊接无法使用传统的储罐倒装埋弧自动横焊机,只能进行半自动焊接,影响整体焊接工效和质量。另外,传统储罐倒装埋弧自动横焊机较高,为了保证焊机操作空间,储罐抗风圈、加强圈等结构件只能在第二层罐壁板高度位置安装,安装高度2.5～5 m,施工安全性差;储罐倒装埋弧自动横焊机焊接轨道固定在罐底部上,用手动摇柄机构调节焊枪上下操作困难。通过改进研发储罐倒装埋弧自动横焊机机架结构、焊剂收集送料系统和电动调节横梁装置等,解决了这些难题,有效提升了储罐的焊接质量和安装效率。     

大型构件横焊机器人的研制

针对船舶、储罐等大型构件的焊接,研制了用于大型构件横焊的机器人,该机器人由轮履式爬行小车、精密十字滑块、激光焊缝跟踪系统、控制系统组成.激光焊缝跟踪系统实时检测焊缝偏差,十字滑块快速调节焊枪位置消除偏差,控制系统根据十字滑块的位置变化情况,控制小车运动.     

利用脉冲技术改善埋弧焊的焊缝成形质量

简述了脉冲埋弧焊的工作原理和焊速提高时改善焊缝成形的机理。介绍了脉冲埋弧焊在锅炉膜式水冷壁焊接生产中的具体应用情况;结合脉冲技术在埋弧自动横焊中的试验情况分析了脉冲埋弧焊在储罐横焊施工中的应用前景。     

焊接机器人自动跟踪系统研究

研究开发了一种光纤式激光焊缝跟踪系统,介绍了该系统的结构组成及工作原理,对焊缝自动跟踪的系统定位、实时跟踪算法、抗弧光干扰等关键技术问题进行了深入探讨.该系统在管道预制焊接机器人的工艺试验表明,系统自动跟踪焊缝稳定性好、精度高,可满足焊接机器人全自动焊作业需求.     

大型储罐正装横缝焊机设计

为了满足当前正装储罐施工和焊接工艺需求,在分析储罐大型化、宽板幅、焊接工作量显著增加等基础上,研发了由车架、动力驱动系统、焊剂循环系统、控制系统及焊接辅助装置组成的新型正装横缝焊机。焊接试验结果表明,该焊机操作方便,焊接行走稳定,焊缝成形美观,效率较高,能够满足大型储罐建设的焊接需求。     

盾构机焊接/切割机器人的研制

针对盾构机盾体结构复杂、焊接耗时长这一问题,设计了全自动焊接/切割机器人.该机器人同时具备焊接/切割功能,能够进行多层多道自动焊接,并满足焊缝自动切割要求;焊接机器人控制系统具有横焊、平焊、立焊三种位置的焊接数据库,每个数据库中层数、道数可灵活设置;具有坡口规划和轨迹存储功能,实现不规则坡口的多层多道自动焊.利用所研发的焊接/切割机器人进行盾体自动焊接及切割试验,试验结果表明,该机器人能够满足盾构机盾体焊缝自动焊接及切割要求.     

盾构机焊接/切割机器人研制

针对盾构机盾体结构复杂、焊接耗时长这一问题,设计了全自动焊接/切割机器人。该机器人同时具备焊接/切割功能,能够进行多层多道自动焊接,并满足焊缝自动切割要求;焊接机器人控制系统具有横焊、平焊、立焊三种位置的焊接数据库,每个数据库中层数、道数可灵活设置;具有坡口规划和轨迹存储功能,实现不规则坡口的多层多道自动焊。利用所研发的焊接/切割机器人进行盾体自动焊接及切割试验,试验结果表明,该机器人能够满足盾构机盾体焊缝自动焊接及切割要求。     

大型储罐双面同步埋弧焊技术的研发及应用

为满足大型储罐快速、高效施工的要求,进行了大型储罐双面同步埋弧焊焊接技术研究。该技术与传统的单面埋弧焊技术相比,可实现横焊缝双面同步焊接,且根焊一次成形,无需清根,工效和焊接质量大为提高,焊材节约和节能效果明显。通过现场应用已经形成一套成熟的焊接工艺,具有良好的应用前景。     

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).     

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.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

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.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。