浅谈Q235普通碳素钢与16MnR低合金钢的焊接

根据Q235普通碳素钢与16MnR低合金钢焊接的实例分析和试验结果，阐述了Q235普通碳素钢与16MnR低合金钢焊接结构，在选择焊缝金属填材料时的方法。     

泡沫金属在单、双向载荷作用下的拉伸破坏行为初探

采用低载拉伸试验机对多孔体的单、双向拉伸进行了系列实验，通过分析该材料的单向拉伸破坏机制，发现开孔泡沫金属材料的宏观断裂特点既不同于最大拉应力准则的横向断裂，也不同于最大剪应力准则的塑性流动破坏，而是表现为介于它们之间的一种复杂断裂形式；拉伸断裂过程中多孔体的延伸率主要由三维网络中的金属丝体发生的塑性偏转所造成。通过其双向承载时断裂形态的观测分析，发现泡沫体十字型样品在双向等速拉伸载荷作用下的应力场分布与双向异速拉伸载荷作用下的类似，且其应力场的最大应力线为靠近样品中央载荷区边缘的四次对称曲边四边形。     

钎焊材料形态演变及其发展趋势

随着制造业高速发展,钎焊技术应用越来越广,并向绿色化、高效化、自动化和高可靠方向发展。钎焊材料形态对钎焊自动化和可靠性起着至关重要的作用。目前有关钎料的研究主要基于成分、性能、工艺性及应用领域等方面。对于钎料形态方面的系统研究还鲜有报道。在钎焊过程中,采用恰当形状的钎料,可以优化工艺和提高钎焊可靠性。本文以钎料几何形态为主线,系统总结了丝状/条状、棒状、粒状、箔带状、粉末状、膏状、药芯型、非晶态及预制成形等钎料的特点、应用范围、主要代表体系、制备方法及发展现状,重点阐述了粉末、药芯型和非晶态等钎料以及常用钎焊方法所适用的钎料形态。研究认为：未来钎焊材料形态发展方向是绿色、高效、低成本并适应新材料、自动化、数字化及智能化需求。     

REVIEW OF THE RESEARCHES ON MAGNETOSTRICTIVE MATERIALS

1.IntroductionThemagnetostrictivepropertyofthematterwasdiscoveredasearlyas1842byJoule[1].Butitseemsimpossibletousethisimportantpropertyuntil1972whentheteamofCI..k[18]reportedtheirdiscoveryaboutgiantmagnetostrictionatroomtemperature.Allmagnetostrictinnbeforethattimewasrestrictedtocryogenictemperature,forexample,theraresearthelementshavelargemagnetostrictiononlynearOK.After1972,theresearchesonmagnetostrictionbecomemoreandmoreactive.Thereasonmaybethatmoreandmorepeoplerealizetheewideuseofit[5--…     

新型环保药皮钎料环的研制及应用

简述了药皮钎料环研制的背景及意义,详细介绍了药皮成分选定原则和药皮制造技术,对比了药皮钎料环和实心钎焊焊条在节约环保、生产自动化等方面的优势,并阐述了其应用领域。研究结果表明:环保型药皮钎料环实现了钎料和钎剂定量、高效的添加,且不含有机粘结剂,有效减少了焊剂的使用量,节约环保;药皮钎料环在提高生产效率、保证产品钎焊质量、减少环境污染等方面发挥重要作用,这使得药皮钎料环有非常广阔的应用前景。     

Development in applications of porous metals

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钎料钎剂复合型绿色钎料研究进展

钎焊是制造业的关键基础技术之一,复合钎料是践行钎焊绿色化、自动化的重要手段,与传统钎料相比,复合钎料可实现钎剂定位—定温—定时—定量精准反应.综述了国内外钎料钎剂复合型钎料的分类和特点,分析了药芯钎料、药皮钎料、粉末合成钎料等的制备技术、成分设计和典型应用,指出了目前研究的不足,并对复合钎料未来的发展方向提出了建议:借...     

承受扭矩和剪切时开口多孔金属的孔棱失效

以高孔率的三维网状多孔金属(即开口多孔金属)为研究对象,建立其简化结构失效模型。分析多孔构件在扭转和剪切载荷形式作用下由于孔棱发生拉断、剪切和屈曲而引起的失效模式,系统地研究上述两种承载条件下这类多孔体构件受到载荷作用而导致孔棱失效时名义载荷与孔率的数理关系。在此基础上,进一步研究此类材料在不同载荷作用下发生各种孔棱失效模式的载荷条件。结果表明,这些失效模式与多孔金属的材质指标、孔率及承受的载荷大小等因素均有关系,这种关系也可以进行相应的具体数理表征。     

高纯金属铒的制备工艺研究

高纯金属铒是多种功能材料的原材料,其纯度对材料性能有较大影响,结合稀土金属制备工艺,系统研究高纯金属铒制备工艺,为工业生产提供依据。分析氟化铒等原料物像对还原过程的影响,确定最佳还原工艺条件:还原剂过量10%,1570℃保温10 min,金属收率大于95%,分析不同设备对金属纯度的影响,高真空和清洁蒸馏环境的钽片炉多次蒸馏可制备99.9904%(质量分数)的高纯金属铒。     

Adhesion between Nonreactive Liquid Metals and Transition Metal Carbides

On the basis of the experimental work of adhesion(W)data,the adhesion between transition metal car-bides and pure liquid metals which do not react with carbides is studied.In view of great scattering of the ex-perimental values of W,a critical analysis of these results is performed.The selected W values for 9copper/carbide systems and 6 metal/TiC systems are used to discuss the various suggestions concerning themechanism of adhesion and to evidence the role of the valence electrons of the both carbide and metal on theinteractions between metals and carbides.The interactions between a metal and a carbide are essentially metal-lic interactions,resulting from the overlapping of the valence electrons at the metal/carbide interface.     

功能梯度材料制备技术研究进展

航空航天、能源动力等领域高端装备对零部件在多元苛刻环境下的服役性能提出了极高要求,而功能梯度材料作为一种以功能、性能驱动为基础的先进材料,打破了原本耦合在一起的材料性能,允许其中一个或多个性能单独改善,并且使得关键零部件在不同部位具有不同功能与性能成为可能,目前已经展示出了极强的发展潜力。首先介绍了功能梯度材料的梯度特性以及优势,并概述了功能梯度材料的发展情况。其次探讨了目前常用的几种梯度制备技术,主要包括气相沉积、热喷涂、激光增材制造、粉末冶金以及离心铸造等,并针对目前研究热度较高的金属/金属、金属/陶瓷类梯度材料的研究进展进行了总结。最后指出了目前功能梯度材料制备中尚存的关键问题,并对功能梯度材料研究进行了展望。     

铝金属基复合材料表面稀土转化膜

介绍了铝金属基复合材料的发展情况及存在的腐蚀问题,详细评述了铝金属基复合材料表面稀土转化膜在国内外的研究进展及现状,对未来这一技术的发展提出了展望。     

Analysis of dynamic plasma behaviours in gas metal arc welding by imaging spectroscopy

For gas metal arc welding, the effect of CO₂ mixture in a shielding gas on a metal transfer process was investigated through the observation of the plasma characteristics and dynamic behaviour at the droplet’s growth-separation-transfer by the temperature measurement methods which were suitable, respectively, to the argon plasma region and the metal plasma region. At the present experimental conditions, the metal transfer process was a spray transfer type with 100%Ar shielding gas. On the other hand, with 85%Ar + 15%CO₂ shielding gas, the metal transfer process was a globular transfer type in which the arc length was shorter, the width was narrower and the time interval of the droplet separation was longer. For both shielding gases, the metal plasma region near the arc central axis exhibited 6500–7500 K, which was lower than the argon plasma region. With 85%Ar + 15%CO₂ shielding gas, when the metal droplet grew below the electrode wire, the region below the droplet has a high plasma temperature and a high concentration of iron vapour which surrounded the droplet. The region also exhibited a remarkably high electron number density. At the spray transfer process, the argon plasma region had an electron number density twice as high as the metal plasma region. Meanwhile, at the globular transfer process, the metal plasma region had a higher electron number density than the argon plasma region, which corresponded to a higher electrical conductivity near the arc axis. This means that the electric current goes through the arc axis easier than the spray transfer process. This condition increases the temperature below the droplet. The thermal expansion increases the force preventing the droplet from falling down. In consequence, the metal transfer takes the globular transfer type.     

Effect of welding conditions on penetration in mechanized surfacing

The approach to determination of the theoretical dependence of the cross-sectional area of a parent metal in the form of an exponential function of the power (current) of the arc and the welding speed is proposed. The exponents of the required function can be determined on the basis of a small number of experiments. The efficiency of the approach and the possibility of deriving simple equations for the determination of the fraction of the parent metal in the weld metal are shown in the example of mechanized CO₂ surfacing. Shortcomings of conventional welding (surfacing) methods as regards the regulation of the chemical composition of the welded joint are indicated.     

进出口贵金属粉末中贵金属元素的直接测定

本文研究了贵金属含量较高的贵金属粉末中的贵金属元素的直接快速测定方法，研究了试样分解方法、测定介质的影响、元素间的光谱干扰。拟定了最佳工作条件，对进出口实际样品进行了分析，其结果与原子吸收光谱及光度法的测试结果一致性较好。     

高压干法GMAW熔滴排斥过渡形成机理

采用红外激光作为背光源,应用高速摄像系统对高压干法GMAW熔滴过渡进行了研究.以三种不同送丝速度,分别进行了0.1～2 MPa的氩气环境GMAW试验.结果表明,随着环境压力的增加,熔滴过渡形式均转变为排斥过渡.在排斥过渡熔滴长大过程中,始终伴随着电弧弧根沿一侧上爬至熔滴的近焊丝端现象,从而对熔滴产生了不对称的侧向力作用,加之高压环境中弧根面积减小导致熔滴所受的电磁力为熔滴过渡的阻力,两者共同作用最终形成了高压干法GMAW的排斥过渡.通过对比不同环境压力下的弧根位置照片发现,这种弧根上爬现象也同时存在于常压和环境压力较低时.并采用理论模型推导了电弧弧根上爬的条件及影响因素.     

Ultrasonic inspection of austenitic steel joints by coupled‐head scanning

This work covers short-circuit metal transfer in the MIG/MAG process, where the current is the direct regulation variable, in contrast with the conventional mode in which the direct regulation variable is the voltage. It sets out the general theory for this technique and describes a new system, not yet commercially offered, developed by LABSOLDA at UFSC. The control bases of the process are described, presenting oscillograph results and performance results in relation to root passes and production of splatter. In addition, some results from an existing commercial system are set out with the aim of making direct comparisons between the control strategies and the implications for the largest dependent factors, such as drop diameters, average current, arc efficiency and arc power. Questions are posed such as the criteria for monitoring the variables and the calculations for arc power, which are as important for these new technologies as they are in the case of conventional systems.     

保护气体成分对双丝旁路耦合电弧GMAW旁路熔滴过渡形式的影响

双丝旁路耦合电弧GMAW的旁路焊枪选择了正极性接法即焊丝接电源负极,旁路熔滴仅依靠重力向熔池过渡,旁路熔滴尺寸较大且过渡过程并不稳定.针对这一问题,采用已建立的双丝旁路耦合电弧焊接过程信号控制与高速摄像采集系统,采集了纯氩气保护时旁路熔滴过渡形式,并分析了旁路熔滴尺寸较大且过渡过程不稳定的原因.在此基础上,采用80% Ar+20% CO₂为保护气体进行了焊接试验.结果表明,焊接过程中,保护气体中的O元素在旁路熔滴表面形成了氧化膜,旁路电弧在旁路熔滴表面的氧化膜上稳定燃烧,从而使电磁收缩力重新作用在旁路熔滴上并促进旁路熔滴向熔池过渡,因此焊接过程中旁路熔滴尺寸明显减小,熔滴过渡过程更加稳定.     

金属焊接艺术初探

探讨了一种新兴的艺术形式——金属焊接艺术,它是在金属艺术创作中主要使用焊接(切割)技术,并且主要通过金属在焊接(切割)过程中发生的变化而形成的独特的艺术语言。详细介绍了焊接艺术的分类,并举例说明了焊接艺术作品的创作过程和创作方法,阐述了焊接艺术的独特艺术魅力和制作工艺。