铝合金板翅式散热器真空钎焊工艺参数研究

采用真空钎焊方法钎焊铝合金板翅式散热器,通过对比钎缝处成分和组织,深入分析了铝合金板翅式散热器虚焊的原因.采用了数学上的统计试验方法以及专用的Minitab统计数据分析软件进行钎焊工艺试验,获得了优异的真空钎焊工艺参数和高质量钎缝,大幅度提高了铝合金板翅式散热器真空钎焊工艺的稳定性.     

6061铝合金与可伐合金钎焊接头残余应力分析

为探究钎焊接头中残余应力分布问题,选用Au80Sn20/Sn63Pb37两种共晶钎料分别钎焊6061铝合金/4J34可伐合金基板,形成钎焊接头进行试验。选取不同的钎焊工艺参数(钎焊温度、钎焊时间等),以研究钎焊工艺对钎缝残余应力分布的影响规律,并进一步对残余应力进行数值模拟和研究。结果表明,残余应力均为拉应力,且靠近可伐合金侧钎缝的残余应力更高,钎焊接头在可伐合金侧钎缝更容易出现断裂;对于Au80Sn20钎料,在相同钎焊温度下,随着钎焊时间的增加,铝合金侧钎缝处的残余应力会略有增大;对于Sn63Pb37钎料,不同的钎焊温度和钎焊时间对数值结果影响不大。X射线残余应力实测结果与计算值的一致性良好,证明了模拟计算结果的正确性,为研究电子产品中轻质合金钎焊接头的可靠性提供了一种有效方法。     

BNi6+9％ Cu复合钎料真空钎焊纯铁的组织分析

采用BNi6+9％Cu复合钎料真空钎焊纯Fe,研究了不同钎焊工艺对焊接接头组织的影响.通过金相试验、扫描电镜及能谱仪等设备观察了接头钎缝形貌,分析了组织成分.结果表明:BNi6+9％Cu钎料真空钎焊纯Fe,当钎焊温度较低时,由于钎料中添加熔点较高的Cu元素及母材Fe的溶解,钎料流动性下降.由于钎料外置,液态钎料填缝过程中与母材的动态冶金作用使不同钎缝处的成分不同,则对接头组织的有较大的影响.钎缝头部反应剧烈,扩散区中柯肯达尔孔洞较多,且在Ni-P金属间化合物中容易形成裂纹;而在钎缝尾部金属间化合物呈岛状,两侧孔洞明显减少,未发现裂纹.综合分析,BNi6+ 9％Cu复合钎料真空钎焊纯铁在钎焊温度950℃、钎焊间隙30μm的钎焊工艺下,能够得到流动性好、柯肯达尔孔洞和裂纹较少的钎焊接头.     

CuMnNiSi钎料钎焊不锈钢接头组织性能研究

采用新型的Cu-Mn-Ni-Si钎料真空钎焊2Cr13不锈钢,研究了钎焊温度和保温时间对接头组织和室温力学性能的影响.结果表明:钎焊接头组织由钎缝中心区Cu-Mn基固溶体和钎缝界面反应区的(Fe,Ni,Mn)- Si化合物组成.随着钎焊温度的增加,钎缝界面处化合物层厚度减小,Cu-Mn基固溶体相应增多,接头室温剪切强度随之增加,在钎焊时间15min、钎焊温度1050℃时达到321 MPa.在钎焊温度1000℃时,接头室温剪切强度随着钎焊保温时间的延长先增加后降低,在钎焊保温时间30min时取得最大值305 MPa.     

高硅铝合金的钎焊性能试验研究

本文针对高硅铝合金的物理性能,分别采用BA188SiMg、纯铜箔、纯锌片作为钎料对其进行炉中钎焊试验,观察分析钎缝的外观成形和金相显微组织。结果表明：高硅铝合金的钎焊性较好,在焊前仔细清除表面氧化膜后,所采用的三种钎料均能与其形成良好的接头;加热温度、保温时间以及钎料厚度对钎缝质量有显著影响。．     

Al-60Si合金低温超声波辅助钎焊接头微观组织与力学性能

采用SnAgCu钎料对Al-60Si合金进行了超声波辅助低温钎焊,发现Ag元素可以与Al元素结合形成一层Ag2Al,促进钎料对母材的润湿和溶解.研究了钎焊温度及超声波作用时间对接头力学性能与微观组织的影响.结果表明,随着钎焊温度的升高,钎缝中的硅颗粒平均质量分数随之增加,由焊接温度240℃时的1.11％提高至钎焊温度3...     

Study on Microstructure of 6061 Aluminum Alloy Brazed with Al-Si-Zn Filler Metals Bearing Sr and Ti

制备了Sr及Ti变质的Al-Si-Zn钎料,并将其应用于6061铝合金的钎焊,研究Sr及Ti对Al-Si-Zn钎料6061铝合金钎焊性能的影响。结果表明：锌的加入使得钎料熔点由铝硅共晶温度下降至520 ℃左右。添加少量改性元素Sr及细化晶粒元素Ti,极大优化了钎料中Al-Si共晶的形态与分布,同时也细化了钎料中的α-Al固溶体。向钎料中添加0.08%Ti元素,使得原来Al-Si-Zn-Sr-0.04Ti钎料钎缝中大块团簇状的铝硅共晶均匀分布于α-Al固溶体之间。在6061铝合金钎的焊界面处可以发现较为明显的过渡层,由于钎焊过程中母材元素发生了向钎料中扩散,母材中的锰元素与钎料中的铁杂质生成块状锰铁相避免了针状β-Fe的生成     

钛丝的钎焊对接

采用高频感应钎焊的方法,研究了Ag及AgCu28钎料对钛丝钎焊性能的影响.当钎焊保温时间大于1.0 s时,BAg与BAgCu28钎缝的抗拉强度分别达到了550 N与160 N.钎缝的金相及X射线衍射分析表明,钎缝中不存在Ti-Ag及Ti-Cu金属间化合物,快速感应钎焊过程可以抑制钎料组元和母材之间的化学反应及母材晶粒的长大,即使采用熔点较高的钎料,也可以获得高性能的钎焊接头.     

AZ31镁合金的钎焊试验研究

本文采用Al-Si-Mg钎料和Cu箔对AZ31镁合金进行真空炉中钎焊试验。试验结果表明：AZ31镁合金的炉中钎焊可以得到冶金结合的钎缝,但钎缝区外围会出现严重的氧化溶蚀沟槽,钎缝内会出现不同程度的孔洞缺陷,其中用Cu箔作中间层的接触反应钎焊效果较好一些。     

铜-低碳钢钎焊接头的耐蚀性评价

通过动态挂片腐蚀实验、宏观和金相组织观察、SEM 及能谱分析等方法对采用Cu-Zn钎料、Ag-Cu钎料、Cu-P钎料钎焊的无氧纯铜-低碳钢管钎焊 接头的耐蚀性能进行了评价分析.结果表明：采用Cu-P钎料时钢和钎缝间出现裂纹，接头遭 受腐蚀后铜管内壁普遍腐蚀，同时钎缝因腐蚀而开裂；Cu-Zn钎缝成型好，但钎缝 本身出现由于金相组织发生选择性腐蚀而引起的局部蚀坑，铜管对应处也出现明显减薄性腐 蚀；Ag-Cu钎料所焊接头成型好，接头各处腐蚀轻微.建议采用Ag-Cu钎料进行铜-低碳钢的 钎焊.     

高效铝合金涂层焊丝的应用与发展

在普通钢焊丝表面热浸涂铝合金涂层后，通过CO2气保焊、埋弧焊的试验研究，证明铝涂层焊丝具有表面不易锈蚀、高的熔敷率、改善导电性、提高合金元素过渡系数、减小气孔生成倾向等特点。在不同焊接方法中适当调整涂层与钢材成分、或配以相应的焊剂类型，可获得不同强度等级的焊缝性能。涂层中还可添加稀土合金和钛、硼等合金元素，以改善焊缝的冲击韧性．本文以冶金观点对“涂层”焊丝所具有的特点和性能的现状与发展进行分析和讨论。     

Fatigue properties of friction stir welds of treated Al to carbon fibre-reinforced plastic

The purpose of this paper is to establish the welding technology for dissimilar materials of carbon fibre-reinforced plastic. Therefore, this study focused on friction stir spot welding, which can be simply substituted for spot welding which is widely used for welding of automobile body. In this study, friction stir spot welding was used to weld joints of carbon fibre-reinforced plastic and aluminium alloy, and the effect of aluminium alloy surface treatments on the fatigue properties and the fracture mechanism of dissimilar material joints were investigated experimentally and statistically. As a result, it is possible to create welding joints with high fatigue durability by using the surface treatments on the aluminium alloy.     

铝/钢异种金属Nd:YAG激光-MIG复合热源熔-钎焊接工艺

铝与钢异种金属的优质高效焊接一直是焊接领域的一项技术难题.针对铝与钢焊接的技术困难和特点,提出了可实现铝与钢熔-钎连接的大光斑激光-电弧复合热源焊接方法,用该焊接方法实现了5A02铝合金板与镀锌钢板的优质高效连接.试验结果分析表明,接头钢母材未发生熔化,焊缝与钢母材为钎焊连接,拉伸试样的破坏位置发生在接头铝母材热影响区,接头的抗拉强度与铝合金电弧熔化焊接头强度相当.     

铁道车辆用铝材的焊接特性

对高速列车用６０６３、６０６１、９１９（相当于７００５）铝合金母材及与之相匹配的焊丝（４０４３、５１８３、５３５６铝合金丝）施以ＭＩＧ焊接之后的焊区强度、硬度以及焊接接头的腐蚀倾向、残余应力水平和常见的焊接裂纹与气孔等缺陷进行了分析和研究。结果表明，由于产生了软化，焊缝及热影响区的强度和硬度均低于母材；从综合效果来看，以母材６０６１合金匹配４０４３焊丝为佳；从焊后强度和刚度看，中空型材的截面以斜筋截面为优；从焊接接头的可靠性看，以纵向ＭＩＧ自动焊接对接为最好     

基于视觉技术的铝合金TIG焊接过程自适应控制

将视觉传感技术与自适应控制技术相结合用于铝合金TIG焊接过程质量控制。分析了铝合金焊接过程的特点，将随机系统理论引入焊接过程，建立了焊接参数与熔池几何参数之间的随机系统模型，实现了对模型参数的在线辨识。设计了基于最小方差调节的自适应焊接电流调节器。试验结果表明，自适应控制方法可以实现对铝合金TIG焊缝成形的良好控制。     

Welding equipment for reinforcing the edges of corrugated walls of the casings of transformers of a new generation of TMG series

The application of aluminium alloy, which is a typical lightweight material, has been expected in the construction of transportation vehicles to achieve energy saving by reduction of weight. However, structures made of whole aluminium alloy have problems with low strength and high cost. Thus, hybrid structures made of Al alloy and steel are useful because of light weight and higher strength. To construct the hybrid structure, it is necessary to weld aluminium alloy and steel. However, conventional welding methods, like brazing and mechanical fastening, have problems such as low mechanical strength and low productivity. Also, it is difficult to weld Al alloy and steel by conventional fusion welding.

In this study, spot welding between aluminium alloy and low carbon steel by friction stirring was carried out. Especially, optimization in welding conditions was carried out. Moreover, the effect of welding conditions on the joint strength and weld interface was studied. As a result, relatively higher tensile shear strength of the weld, which was achieved at optimum welding conditions, was obtained. Temperature near weld interface measured by K-type thermocouple during welding was found to be lower than the melting point of A5052. From the observation results on microstructure of the weld interface, it was found that a Fe/Al intermetallic compound layer was formed.     

铝制船的焊接工艺及应用研究

某公司承建的一艘全铝制船,其船体材料主要采用5083H116/H321铝镁合金板材与6082-T6铝镁硅合金型材.全船焊接以自动及半自动MIG焊为主,TIG焊为辅(主要是管系焊接).介绍了全船的铝板/铝管焊接工艺评定特点,探讨了实际生产中影响焊接质量的主要因素,以及如何解决气孔超标等现场铝焊问题.研究表明,铝镁合金焊接的主要缺陷是气孔及裂纹,在实际生产中应控制焊接参数、焊接操作、焊丝、氩气、焊接设备等影响因素.在焊工培训中应将传统的理论、技能培训与产品现场的适应性培训相结合.     

T91/P91钢的焊接工艺

主要介绍了T91／P91材料的特点以及其在焊接过程中容易出现的焊缝性能和HAZ性能的劣化问题，分析了T91／P91材料的焊接性，介绍了T91／P91的焊接工艺、热处理工艺以及在实际焊接施工过程中经常遇到的问题以及预防方法。通过采取合适的预热温度、焊接工艺方法和焊后热处理工艺，可以解决T91／P91焊接过程中易出现的焊缝性能和HAZ性能的劣化问题，保证焊口的质量并使焊缝、熔合区及其热影响区能够获得较好的性能，满足其在火电厂中的高温运行要求。     

Fluxless laser beam joining of aluminium with zinc coated steel

Abstract

A laser welding–brazing (LWB) process to join zinc coated steel and aluminium sheets in two different flange geometries is reported. The deep drawing steel sheets are covered by a zinc layer of maximum thickness 10 μm, and a zinc based filler wire was used in the welding experiments with a Nd–YAG laser. Because of the differences in melting temperatures between iron (1808 K), aluminium (933 K), and zinc (693 K), it is possible to weld the aluminium alloy only. Owing to the zinc coating on the steel side, a Zn–Al alloy can be brazed onto the steel without any flux agent. The inevitable formation of a Fe–Al intermetallic phase at the bondline of the weld seam and the steel can be limited to a thickness of less than 5 μm and to a proportion of the contact area only. Mechanical as well as dynamic tests show results comparable to those obtained via other joining techniques. Salt chamber corrosion tests of varnished specimens display minor damage and no decline in tensile strength.     

Optimisation of friction stir welding process parameters to weld cast aluminium alloy A413 – an experimental approach

Abstract

A413 is a high strength eutectic aluminium silicon cast alloy used in the food, chemical, marine, electrical and automotive industries. Fusion welding of these cast alloys can lead to problems such as porosity, microfissuring and hot cracking, etc. However, friction stir welding can be used to weld these cast alloys effectively, without defects. In this investigation, an attempt was made to optimise the friction stir welding process parameters for joining the cast aluminium alloy A413. Joints were made using four levels each of tool rotation speed, welding speed and axial force. The quality of the weld zone was analysed using macrostructure and microstructure analysis. Tensile strength of the joints were evaluated and correlated with the weld zone hardness and microstructure. The joint fabricated using a tool rotation speed of 900 rev min^?1, a welding speed of 75 mm min^?1 and an axial force of 3 kN showed the best tensile strength.