6009铝合金光纤激光-MIG电弧复合焊和光纤激光焊工艺对比研究

采用光纤激光-MIG 复合焊和光纤激光焊分别对6009铝合金进行焊接,研究两种焊接方式下焊接接头的成型性、显微组织、拉伸性能、显微硬度、断口形貌的不同。研究表明：激光电弧复合焊的焊接速度是激光焊接的3倍;相比于激光焊,激光电弧复合焊焊缝中心显微组织更加细小;接头的抗拉强度达到母材的63%以上,而激光焊接的抗拉强度仅仅只有母材的38%;显微硬度试验表明：复合焊存在软化区,而激光焊接几乎没有软化区;断口分析表明：复合焊和激光焊的拉伸断口都是典型的韧窝状态,但是复合焊接的韧窝更加均匀。     

不锈钢/铝合金异种金属激光-MIG熔钎焊工艺研究

分别采用激光-MIG复合焊和单MIG焊,实现了2mm厚的304不锈钢和6061铝合金对接接头的熔钎焊,对比了不同焊接热源对接头显微组织、界面层化合物及力学性能的影响。结果表明,采用激光-MIG复合焊可以获得性能良好的不锈钢-铝对接接头。激光-MIG复合焊接头的界面层化合物为FeAl_2和Fe_4Al_(13),厚度约为5μm;而单MIG焊接头的界面层化合物厚度约为3μm,主要为Fe_4Al_(13)。激光-MIG复合焊接头的抗拉强度为105MPa,比单MIG焊接头提高了10.8MPa,达到铝合金母材的33.9%。接头试样拉伸断裂均起裂于钎焊界面处,并向余高处扩展,且由脆性断裂转变为韧性断裂。     

高速列车用铝合金型材激光-MIG复合焊工艺特性和接头性能

激光-MIG复合焊是实现高速列车铝合金车体优质、高效、低成本焊接制造的理想技术。针对高速列车铝合金车体用的3 mm厚6A01-T5铝合金型材，开展激光-MIG复合焊工艺试验，研究工艺参数对焊缝成形及气孔缺陷的影响规律，分析接头的组织特征、硬度分布、拉伸及疲劳性能。结果表明:在满足焊缝熔透条件下，较小的激光功率、较小的电弧电流或较低的焊接速度有益于减少气孔缺陷;接头组织从焊缝中心到母材依次是等轴晶区、柱状晶区、半熔化区、过时效区和母材区，相比电弧主要作用区，激光主要作用区的等轴晶尺寸更小且半熔化区宽度更窄。接头存在软化现象，焊缝区硬度最低，热影响区宽度约1.5 mm;接头的平均抗拉强度达197.5 MPa，为母材抗拉强度的80.6%，试样断裂于焊缝区，表现为明显的韧性断裂特征;接头的疲劳强度为93.5 MPa，裂纹萌生于焊缝表面的组织疏松处，裂纹扩展区断口呈现明显的韧性断裂和脆性断裂的混合断裂特征。     

AZ33M变形镁合金激光焊接接头的组织和性能研究

目的研究AZ33M变形镁合金激光焊接工艺及焊接接头的组织和性能。方法通过对2 mm厚AZ33M变形镁合金板材进行激光焊接,采用金相显微镜、扫描电子显微镜、X射线衍射仪、万能试验机等研究了焊接接头的微观组织、物相组成、元素分布、力学性能,并研究了焊后均匀化处理对接头组织及性能的影响。结果焊接接头的焊缝边缘晶粒形态以柱状晶为主;焊缝中含有α-Mg, Mg_(17)Al_(12), MgZn,MgZn_2,Mg_7Zn_3等5种物相。结论通过调整焊接功率、焊接速度和离焦量可以获得力学性能与母材基本一致的焊接接头;中等功率焊接的焊接接头抗拉强度均能达到母材的95%以上,该变形镁合金焊接性能较优异。     

12 mm厚TC4钛合金激光-MIG复合焊接头组织与性能研究

目的 探究TC4激光-MIG复合焊接头显微组织与基本力学性能之间的联系,分析接头不同区域的断裂行为。方法 利用激光-MIG复合焊制备TC4钛合金对接接头,采用光学显微镜和扫描电镜观察接头焊缝区、热影响区及母材的显微组织,在室温下进行了显微硬度测试、拉伸性能测试与断裂韧性测试,并对试样断口进行了观察分析。结果 接头的焊缝区组织为粗大的β相柱状晶,晶内纵横分布着αʹ针状马氏体和针状α相,靠近焊缝一侧的热影响区则由针状αʹ相、α集束与少量细小的块状α相构成。随着远离焊缝中心,母材侧热影响区组织转变为块状的α相、少量α集束及初生β相,并最终趋于与母材组织相似。热影响区的显微硬度值达到最大,这是因为该区域存在比焊缝区更为细小的针状αʹ相。接头的平均抗拉强度和断后伸长率分别为1 020.22 MPa和7.38%。接头在拉伸时主要在焊缝区发生断裂。焊缝区展现出比母材区和热影响区更优异的断裂韧性,平均值为87.14 MPa.m^1/2,焊缝区内纵横交错的网篮组织与集束是其断裂韧性较高的主要原因。结论 在TC4钛合金的激光-MIG复合焊过程中,针状α相和αʹ马氏体的存在会提高焊缝的显微硬度和断裂韧性,但相较于母材塑性没有提升,通过调控焊缝区显微组织结构,可以获得所需性能的接头。     

不锈钢激光-MAG复合焊接头微区性能研究

激光复合焊可用于不锈钢焊接,但激光复合焊接头热影响区小,组织变化梯度大.研究接头微区性能可以确定接头薄弱环节,为焊接接头的工艺评定和断裂分析提供理论依据.为此,本文对4 mm厚SUS301L-HT不锈钢进行激光-MAG复合焊接,采用维氏硬度、微型剪切和微拉伸等试验,研究了焊接接头焊缝、热影响区及母材的微区力学性能,并结合金相、断口扫描等分析了各微区力学性能的差异.结果表明：焊缝区域组织主要为柱状奥氏体树枝晶+少量的δ铁素体;母材的剪切强度和抗拉强度最高,分别为560和1 066 MPa,其次为复合焊接头热影响区,焊缝区域最差,接头硬度分布规律与各微区强度变化趋势一致;运用数学方法,得出了接头微拉伸强度与微型剪切强度、硬度之间关系的经验公式.接头各微区剪切断口和拉伸断口SEM分析呈现典型的韧性断裂特征.     

热等静压工艺对铝合金激光焊接T型接头组织及缺陷的影响

以3.3mm厚6A02铝合金板材为试验材料,对热等静压处理前后铝合金激光焊接T型接头的组织及气孔缺陷进行了分析。结果表明:热等静压前6A02铝合金板母材显微组织为Mg2Si等强化相固溶于α(Al)基体中,焊缝显微组织为树枝晶,存在明显的气孔缺陷;合理地选择热等静压工艺,可有效消除接头的焊后气孔缺陷,并提高母材的显微硬度,降低焊缝中心的显微硬度;而过高的热等静压压力和温度会使接头出现过烧组织,大幅度降低其显微硬度。     

镁/钢激光-电弧复合焊接接头的腐蚀行为

采用激光-电弧复合填丝对接焊方法获得了成形及力学性能良好的AZ31B镁合金/Q235钢板焊接接头;利用金相显微镜和电子探针观察焊接接头组织和元素分布状态,通过浸泡腐蚀试验和电化学试验研究了焊接接头不同区域(镁母材、焊缝、钢母材)的腐蚀行为。结果表明:AZ31B母材存在各向异性的腐蚀现象;焊缝与钢母材之间发生电偶腐蚀,邻近界面处的焊缝腐蚀严重,而界面处富集Al、Mn元素,腐蚀倾向较小;焊缝中存在较多钢飞溅,钢飞溅周围的区域比焊缝其他位置的腐蚀更为严重,焊接过程中产生的钢飞溅对焊缝的耐蚀性是不利的;焊缝中的β相一方面作为屏障层阻碍基体的腐蚀,另一方面作为电偶腐蚀中的阴极增加焊缝基体的腐蚀敏感性。     

ZC71镁基复合材料激光焊接接头组织分析

前言:研究表明,镁基复合材料激光焊接接头的组织没有明显的热影响区,焊接接头狭窄,接头成形较好,焊接接头晶粒细小;Mg在焊接接头中蒸发,引起Zn含量的相对增加,但并不严重;运用扫描电镜观察了焊缝区以及母材区的金相组织,并进行对比,结果表明镁基复合材料的激光焊接接头微观组织与母材相     

压水堆一回路冷却剂中加锌对不锈钢焊接接头腐蚀行为的影响

为研究AP1000一回路冷却剂中加锌对安全端同材焊接区域的影响,采用金相显微镜、扫描电镜(SEM)、能谱仪以及X射线光电子能谱仪(XPS)等测试方法,分析了316LN/316L不锈钢焊接接头在模拟压水堆一回路冷却剂加锌环境下的氧化特性.结果表明:焊接接头母材区、热影响区和焊缝区的金相组织之间存在明显的熔合线,母材区与热影响区均为奥氏体,且热影响区晶粒稍显粗大,焊缝区则有少量铁素体析出;未加锌环境中母材区氧化膜呈黑色,焊缝区氧化膜呈暗红色,氧化膜表面与焊缝区无明显差异;加锌10 μg/L母材区与焊缝区氧化膜均呈现黑色,比未加锌时焊接接头氧化物的颗粒更小,未加锌焊缝区的氧化膜比母材区更薄;加锌溶液中各区域氧化膜厚度趋于一致,比未加锌的减小近45％.     

Hybrid laser-Metal Inert Gas welding of Al–Mg–Si alloy joints: Microstructure and mechanical properties

Hybrid fiber laser-Metal Inert Gas (MIG) welding is an advanced joining technology that is increasingly employed in the modern industry. In this paper, hybrid fiber laser-MIG welding was applied to join 5 mm thick AA6005-T5 alloy used in the carbody of high-speed railway vehicles. The mechanical properties of the hybrid welded joints were investigated. The results showed that the hybrid welded joints have more excellent mechanical properties than that of the MIG joints. However, there is still strength loss in the hybrid welded joins comparing with the base metal. The reason for the loss of the strength was studied from the aspects of microstructure and vaporization of strengthening elements.     

Study on arc and laser powers in the hybrid welding of AA5754 Al-alloy

In this paper a new generation of fiber laser assisted by a MIG source was used to weld AA5754-H111 aluminum alloy in 3 mm thick butt configuration. The effects of laser and arc powers on the weld geometry and properties were studied. Weld geometry and porosity were measured. The microstructure was investigated by optical microscope and Vickers micro-hardness was taken. The residual stress close to the heat affected zone was measured by the incremental hole-drilling method. Eventually, the tensile test was conducted in order to compare the mechanical properties of the weld with those of the parent metal.For the first time the sensitiveness of the hybrid welding of the 5754 aluminum alloy to the arc and laser powers was demonstrated. Higher laser power favored the stability of the process and provided good structural and geometrical properties of the weld. Further investigation can be performed in order to optimize the weld soundness and the energy efficiency of hybrid welding an aluminum alloy using a fiber laser.     

环境温湿度对铝合金焊缝气孔和力学性能的影响

对于高速轨道客车铝车身的生产制造,气孔是焊接中最常见的缺陷。采用X射线法研究了不同温度和湿度下铝合金6082和5083熔化极氩弧焊(MIG)焊缝的气孔情况。结果表明,在焊接过程中环境的绝对湿度(是温度和湿度的综合体现)对焊缝的气孔率有重要影响,铝合金6082焊缝的气孔敏感性要比铝合金5083高。在拉伸试验中铝合金6082接头的断裂位置一般在焊接热影响区(HAZ),随着绝对湿度的增加,接头的抗拉强度和断后伸长率几乎保持不变,但接头的正弯和背弯角度分别减小了74.4%和64.4%。铝合金5083接头的断裂位置一般出现在熔合区,随着绝对湿度的增加,接头的抗拉强度和断后伸长率分别减小了4.0%和15.7%,但是弯曲性能变化不大。     

An investigation of the microstructures and properties of metal inert gas and friction stir welds in aluminum alloy 5083

Two different types of welds, Metal Inert Gas (MIG) and Friction Stir Welding (FSW), have been used to weld aluminum alloy 5083. The microstructure of the welds, including the nugget zone and heat affected zone, has been compared in these two methods using optical microscopy. The mechanical properties of the weld have been also investigated using the hardness and tensile tests. The results show that both the methods could successfully be used to weld such alloy. The strength of the joints is comparable to the strength of the base metal in both cases. However, FSWed samples have shown higher strength in comparison to the MIG samples. The results also show that the extension of the heat affected zone is higher in the MIG method in comparison to the FSW method. The weld metal microstructure of MIG welded specimen contains equiaxed dendrites as a result of solidification process during MIG welding while FSWed samples have wrought microstructures.     

A comparative study of laser beam welding and laser-MIG hybrid welding of Ti-Al-Zr-Fe titanium alloy

Ti-Al-Zr-Fe titanium alloy sheets with thickness of 4 mm were welded using laser beam welding (LBW) and laser-MIG hybrid welding (LAMIG) methods. To investigate the influence of the methods difference on the joint properties, optical microscope observation, microhardness measurement and mechanical tests were conducted. Experimental results show that the sheets can be welded at a high speed of 1.8 m/min and power of 8 kW, with no defects such as, surface oxidation, porosity, cracks and lack of penetration in the welding seam. In addition, all tensile test specimens fractured at the parent metal. Compared with the LBW, the LAMIG welding method can produce joints with higher ductility, due to the improvement of seam formation and lower microhardness by employing a low strength TA-10 welding wire. It can be concluded that LAMIG is much more feasible for welding the Ti-Al-Zr-Fe titanium alloy sheets.     

Microstructure characteristics of thick aluminum alloy plate joints welded by fiber laser

It's difficult to weld high strength thick plate since the groove is huge when using traditional arc welding, and the weld tends to be softened and large deformation could occur after multi-layer welding. All of these can affect the industrial application of high strength thick plate wielding. In this case, developing advanced welding technology and welding material is necessary to optimize the microstructure and performance of the welds. Fiber laser has many advantages such as good monochrome and high quality laser beam. In order to decrease the heat damage to the base metal from the welding heat source, low heat input is employed for welding thick plate. Fiber laser is applied in the welding of 20 mm thick Al–Zn–Mg–Cu alloy with super narrow gap filler wire. The microstructure comparison of Al–Mg–Mn alloy and Al–Mg–Mn–Zr–Er alloy welded joints reveals that a huge amount of fine equiaxed grains is formed in the weld zone of Zr and Er micro-alloying Al–Mg–Mn alloy welding wire and a great number of precipitation strengthening phases are precipitated in the weld zone after the heat treatment of welded joints in the entirety.     

环境温湿度对铝合金焊缝气孔和力学性能的影响

对于高速轨道客车铝车身的生产制造,气孔是焊接中最常见的缺陷.采用X射线法研究了不同温度和湿度下铝合金6082和5083熔化极氩弧焊(MIG)焊缝的气孔情况.结果表明,在焊接过程中环境的绝对湿度(是温度和湿度的综合体现)对焊缝的气孔率有重要影响,铝合金6082焊缝的气孔敏感性要比铝合金5083高.在拉伸试验中铝合金6082接头的断裂位置一般在焊接热影响区(HAZ),随着绝对湿度的增加,接头的抗拉强度和断后伸长率几乎保持不变,但接头的正弯和背弯角度分别减小了74.4％和64.4％.铝合金5083接头的断裂位置一般出现在熔合区,随着绝对湿度的增加,接头的抗拉强度和断后伸长率分别减小了4.0％和15.7％,但是弯曲性能变化不大.     

等离子弧焊接铝及其复合材料研究进展

铝合金及铝基复合材料在船舶、汽车、电子电器、航空航天等许多行业中有着广阔的应用前景。而焊接技术是其广泛应用的技术关键。重点介绍了等离子弧焊技术在铝合金及铝基复合材料中的应用现状,综述了等离子弧焊接接头的微观组织性能、铝合金等离子弧焊数值模拟及新型等离子弧焊的应用,并总结了等离子弧焊接铝合金及铝基复合材料目前存在的主要问题,展望了其未来的发展趋势。