无镀铜实心焊丝抗锈及工艺性能的研究现状

无镀铜焊丝是应用纳米和现代金属间化合物胶体涂层相结合的新型焊接材料,对焊丝表面进行特殊的涂层处理技术,因此其也被称为涂层焊丝或活性焊丝。文中主要阐述了无镀铜焊丝在抗锈性能、电弧稳定性、熔滴过渡形式、飞溅率及发尘量、导电嘴磨损等方面的国内外研究现状,并探讨了无镀铜焊丝未来研究的发展方向。     

《T/CWA 0001-2017无镀铜焊丝》团体标准荣获2017年度黑龙江省机械工业科学技术一等奖

由机械科学研究院哈尔滨焊接研究所李连胜、方乃文、马青军,中国焊接协会杜淼、李波、吴妍,哈尔滨现代焊接技术有限公司、黑龙江省焊接协会林晓辉等人参与制订的《T/CWA 0001—2017无镀铜焊丝》团体标准荣获黑龙江省机械工业科学技术一等奖。该标准为中国焊接行业发布的首个团体标准,根据无镀铜焊丝特点与实际生产应用情况对技术要求及试验方法进行了科学设置,体现出无镀铜焊丝对铜含量的特殊要求、规定了抗锈性能测试方法、飞溅率测试方法以     

CO_2焊丝表面状态对焊接工艺性能影响的试验分析

一、问题的提出: 在CO_2焊接施工中,发现相同牌号、相同直径的(HO8Mn2Si焊丝、φ0.8和φ1.0)焊丝,其焊接工艺性能完全不同。即1号焊丝,施焊时工艺性能良好,2号焊丝施焊中,送丝阻力大,声音爆,飞溅大,断弧,焊丝与导电嘴常发生不同程度粘连,且焊缝成形不良。尽管对盘丝机、送丝轮、送丝软管、导电嘴以及焊接规范进行了必要的改进与调整,都收效不大。     

无镀铜桶装焊丝在机器人焊接中的应用

采用烟尘测定装置检测了无镀铜桶装焊丝的发尘量,采用波形测定仪检测了无镀铜桶装焊丝的电弧稳定性和送丝性能,采用焊丝测力器检测了无镀铜桶装焊丝的送丝阻力。结果表明,无镀铜桶装焊丝在焊接时发尘量少,电弧稳定,送丝阻力小,焊接飞溅小,焊道成形美观。同时通过观察发现,无镀铜焊丝在机器人焊接中容易出现断弧、跳丝以及送丝不顺的现象,分析了产生这些问题的原因以及应对措施。     

C-MoS2-Fe2O3(Fe3O4)纳米润滑剂对无镀铜焊丝导电嘴磨损的影响

针对无镀铜实心焊丝在机器人自动焊接时导电嘴磨损问题,采用机械涂敷法在无镀铜实心焊丝表面制备了C-MoS₂-Fe₂O₃(Fe₃O₄)纳米复合润滑剂,研究了润滑剂配比对导电嘴磨损性能的影响. 结果表明,C-Fe₃O₄涂层的润滑性能优于C-Fe₂O₃涂层的润滑性能,随着涂层中纳米MoS₂含量的升高,导电嘴的抗磨性能增强. 纳米复合润滑剂在焊丝与导电嘴的摩擦界面发生摩擦化学反应形成了保护性的自修复膜,此膜主要由润滑性能优异的FeO,MoS₂,MoO₃组成,避免了焊丝与导电嘴内表面的直接接触,从而减少了导电嘴的磨损. 氧化磨损、磨粒磨损和电弧烧蚀是导电嘴磨损的主要机制.     

CO2焊焊丝表面镀铜层的质量分析

本文从CO_2焊丝表面镀铜层的质量分析入手,着重讨论了CO_2镀铜焊丝的表面质量与抗腐蚀性能和导电性能的关系.提出镀铜质量低劣的焊丝容易被腐蚀,生锈,在焊接时铜皮剥落,影响焊丝自动输送,同时亦影响焊接工艺的稳定性.镀铜焊丝的质量也直接影响焊丝的生产过程.     

GMAW无镀铜实心焊丝及其应用

详细分析了GMAW镀铜焊丝在生产中的环保问题、污染问题、焊丝本身的质量问题(铜层易剥落、焊接飞溅大、焊缝成型差、防锈不佳)等.为适应我国建筑钢结构技术的发展和节能减排的绿色制造理念,GMAW无镀铜焊丝应运而生.GMAW无镀铜焊丝生产工艺解决了镀铜焊丝生产和使用过程中的铜污染问题,无镀铜实心焊丝具有表面光洁、焊丝的送丝性能更加稳定、在使用过程中不会出现因铜层脱落等问题造成的送丝不穗的现象、焊丝表面更加光滑、并减少送丝阻力等优点.无镀铜焊丝在实际中得到了一定范围的推广应用,获得了好评.     

无缝药芯焊丝在船舶焊接中的研究与应用北大核心

随着药芯焊丝制造工艺的发展,药芯焊丝在船舶焊接材料中约占90%以上,目前使用的药芯焊丝均为有缝药芯焊丝,其焊接效率高、工艺性能好、适应性强,但在焊接时存在送丝较困难,焊丝外表面容易腐蚀、容易吸潮、不易储存和运输等问题。无缝药芯焊丝可以进行表面镀铜处理,焊丝保管过程中的防潮及焊接过程中的导电性均优于有缝药芯焊丝,针对SRSF501无缝药芯焊丝进行熔敷金属试验和工艺性能研究,并将该焊丝在13000 t重吊船上进行应用。结果表明,该无缝药芯焊丝能够满足船舶焊接的要求,并具有一定优异性,将对药芯焊丝的发展具有深远的意义。     

无缝药芯焊丝在船舶焊接中的研究与应用

随着药芯焊丝制造工艺的发展,药芯焊丝在船舶焊接材料中约占90%以上,目前使用的药芯焊丝均为有缝药芯焊丝,其焊接效率高、工艺性能好、适应性强,但在焊接时存在送丝较困难,焊丝外表面容易腐蚀、容易吸潮、不易储存和运输等问题。无缝药芯焊丝可以进行表面镀铜处理,焊丝保管过程中的防潮及焊接过程中的导电性均优于有缝药芯焊丝,针对SRSF501无缝药芯焊丝进行熔敷金属试验和工艺性能研究,并将该焊丝在13000 t重吊船上进行应用。结果表明,该无缝药芯焊丝能够满足船舶焊接的要求,并具有一定优异性,将对药芯焊丝的发展具有深远的意义。     

不锈钢药芯焊丝E308LT1-1对防飞溅剂的适应性改进

通过对不锈钢药芯焊丝E308LT1-1在使用防飞溅剂时,焊接后容易产生气孔进行分析,发现防飞溅剂污染焊接坡口后焊接时产生了大量的气体,导致不锈钢药芯焊丝E308LT1-1焊缝容易产生氢气孔。合理控制氟化物和氧化物的加入量能够提高不锈钢药芯焊丝对防飞溅剂的适应性,使焊缝不产生气孔;合理加入氧化铁和氧化铈不会对该药芯焊丝工艺性能和力学性能产生不良影响。     

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.     

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.     

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。