共查询到20条相似文献,搜索用时 31 毫秒
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水下湿法焊缝成形是影响水下焊接接头力学性能的重要因素.与空气中焊接相比,影响水下湿法焊缝成形的因素更复杂.在高压舱内进行不同水深湿法药芯焊丝焊接(FCAW)试验,通过响应曲面法(RSM)分别建立水下湿法焊缝的熔宽和余高与焊接参数之间的数学模型,分析了焊接电流、电弧电压和水深及其交互作用对水下湿法焊缝成形的影响.结果表明,水下湿法焊接时增大焊接电流和电弧电压都可以增大焊缝熔宽.熔宽随着水深的增大而减小,但随着水深的增大,水深对减小熔宽的作用逐渐减小.随着电流的增大,焊缝余高增大,且比电弧电压对余高的作用明显. 相似文献
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A. Kh. Akhunova E. V. Valitova V. A. Valitov S. V. Dmitriev 《Welding International》2017,31(11):879-882
Computer modelling is used to investigate the possibilities of increasing the quality of welded joints in pressure welding of dissimilar creep-resisting materials in the presence of a relief on one of the welded surfaces. It is shown that the quality of welded joints depends on the geometrical parameters of the welded specimen. 相似文献
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以Q345钢结构箱型柱为对象,研究了超声冲击工艺对焊接残余应力的影响。对电渣焊和埋弧焊两种焊缝进行了超声冲击试验,其中埋弧焊焊缝采用了全覆盖冲击和焊趾冲击两种冲击工艺。残余应力测量表明,采用冲击工艺,可以在焊缝表面一定深度(小于3mm)下产生压应力,最高测得-134MPa;焊趾冲击不但使焊趾表面产生压应力,也降低了焊缝的残余应力。对非熔透埋弧焊和熔透埋弧焊焊缝的测量结果显示,在盲孔法测量的深度范围内,超声冲击可降低焊缝最大主应力约34%~55%。 相似文献
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Using brazing alloys for controlling the quality of resistance spot-welded joints in titanium alloys
Investigations were carried out into the special features of the process of electron beam welding (EBW) with the supply of nitrogen into the weld pool. The effect of the gas medium on the focusing of the electron beam and the depth of penetration is described. The dependence of the chemical composition of weld metal and of the mechanical properties of the welded joint on the amount of supplied nitrogen is determined. It is assumed that it is sufficient to alloy the welded joints in austenitic creep-resisting steels with nitrogen during EBW in order to increase the hot cracking resistance of the weld metal. 相似文献
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Twin roll cast EN AW Al-Mn1Cu plates were butt welded with the friction stir welding process which employed a non-consumable tool, tilted by 1.5° and 3° with respect to the plate normal, rotated in a clockwise direction at 400 and 800 rpm, while traversing at a fixed rate of 80 mm/min along the weld line. Microstructural observations and microhardness tests were performed on sections perpendicular to the tool traverse direction. Tensile tests were carried out at room temperature on samples cut perpendicular to the weld line. The ultimate tensile strength of the welded EN AW Al-Mn1Cu plates improved with increasing tool rotation speed and decreasing tool tilt angle. This marked improvement in ultimate tensile strength is attributed to the increase in the heat input owing to an increased frictional heat generation. There appears to be a perfect correlation between the ultimate tensile strength and the size of the weld zone. The fracture surfaces of the base plate and the welded plates are distinctly different. The former is dominated by dimples typical of ductile fractures. A vast majority of the intermetallic particles inside the weld zones are too small to generate dimples during a tensile test. The fracture surface of the welded plates is thus characterized by occasional dimples that are elongated in the same direction suggesting a tensile tearing mechanism. 相似文献
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A. R. Kohandehghan S. Serajzadeh 《Journal of Materials Engineering and Performance》2012,21(6):892-899
This study concentrates on the effects of weld sequence and welding fixtures on distribution and magnitude of induced arc welding residual stresses built up in butt-joint of Gas Tungsten Arc Welding (GTAW) AA5251 plates. Aluminum plates have been welded under different welding conditions and then, longitudinal and transverse residual stresses were measured in different points of the welded plates employing hole-drilling technique. The results indicate that welding sequence significantly alters the distributions of both longitudinal and transverse residual stresses while the changing in the weld sequence leads to 44% decrease in longitudinal residual stress. Besides, both the geometry of weld pool and distribution of residual stresses are affected by the welding fixtures while implementation of fixture causes about 21 and 76% reductions in the depth of weld pool and transverse residual stress, respectively, for the material and welding conditions used in this research. 相似文献
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分别以3种不同材质铝合金平板材料为试验对象,研究分析了复合超高频脉冲方波变极性钨极氩弧焊接(HPVP-GTAW)过程中电弧力的变化及其对焊缝成形特征和接头力学性能的影响.结果表明,与常规变极性氩弧焊工艺相比,脉冲方波电流的加入使得HPVP-GTAW电弧力显著增加,同时焊缝熔透率大幅提高,接头力学性能得到明显改善和提高;保持脉冲电流幅值和占空比基本不变,在10~80 kHz范围内,脉冲电流频率对焊接过程产生了重要影响,频率为40 kHz时,HPVP-GTAW电弧力和焊缝熔透率均达到最大,分别约为常规变极性焊接电弧的1.9倍和1.7倍. 相似文献
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为明确高熵合金焊接接头耐腐蚀行为,采用电子束方法对共晶双相AlCoCrFeNi2.1高熵合金进行焊接,并运用电化学腐蚀方法研究了接头耐蚀性.结果表明,焊缝区域(FZ)自腐蚀电位相比母材(BM)提高0.16 V左右,耐蚀性增强,自腐蚀电流减小了一个数量级,腐蚀速率明显降低.焊接接头母材区域腐蚀坑呈纵深扩展趋势,而焊缝区域腐蚀坑呈横向扩展,并表现出明显的相选择性腐蚀现象.焊缝区域的晶粒细化显著,硬度升高,两相分布呈现密集的“网络”状,元素分布更加均匀,大角度晶界增加,这都增强了焊接接头的耐点蚀穿孔的能力. 相似文献
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S S Volkov 《Welding International》2013,27(3):243-248
The design of permanent joints with fillet welds characterized by bevelling of the edges with the depth decreasing with an increase in the distance from the weld edge to the centre of the weld is proposed. The experimental results show that in producing permanent joints with the edge bevel of variable depth, the volume of the deposited metal is reduced by 35% with the corresponding reduction in the material requirement of the process without reducing the load-carrying capacity of the welded joint. 相似文献
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EffectsofstrengthmatchingandcrackdepthonthefractureparametersforweldedjointsTangWeiandShiYaowu(Xi'anJiaotongUniversity)Abstra... 相似文献
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研究了锅炉用钢20g厚板电子束焊接深比超过20:1时,焊接接头的组织特点及接头韧性,当焊缝深度比超过20:1时,热影响区将产生高碳马氏体组织,从而造成热影响区的脆化。 相似文献
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采用高功率CO2激光器对MB8镁合金进行一系列激光焊接工艺试验,并对焊缝成形的形成规律、接头的微观组织和力学性能进行研究.结果表明:焊缝熔深基本和激光功率呈正比关系,激光功率每增加1 kW,熔深约增加2 mm.焊缝熔合区组织主要由粗大的等轴晶组成,晶粒内有连续析出的条纹状β-Mn,晶粒尺寸约为60μm;热影响区组织为相对细小但大小不一的等轴晶,晶粒尺寸为15~40μm.在消除焊缝表面缺陷后,焊接接头抗拉强度能达到基材的90%左右.此外,熔合区内的粗大晶粒、晶粒内连续分布的第二相及焊缝内气孔缺陷是造成接头拉伸性能低于基材的主要原因. 相似文献
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研究了31CrMoV9钢电子束焊接接头在焊后去应力退火、焊后调质两种不同焊后热处理状态下的焊缝组织与性能,并与同等强度等级下的母材组织与性能进行了对比研究。结果表明,接头焊后组织为板条马氏体及少量残留奥氏体;焊缝经调质处理后,组织为相对均匀的回火索氏体,接头力学性能与母材相当,相比于焊后去应力退火处理,焊缝冲击性能大幅提高。两种类型的焊后热处理均未消除焊缝柱状枝晶等凝固组织形态,但焊后调质工艺可减轻焊缝柱状枝晶组织偏析,并使之细化,使得焊缝与母材的组织与硬度更加均匀;焊后经多次重复淬火,焊缝经检测均未见裂纹,说明焊后采用调质工艺可行,这为提高焊缝冲击性能提供了可行工艺路线。 相似文献
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The results of investigations of diffusion bonding of an alloy based on titanium nickelide are presented. The effect of the welding conditions on the strength of the joint in sheet semi-finished products is investigated. The experimental results show that the main reason for the reduction in the mechanical properties of the welded joint is the interaction of the weld surfaces with residual oxygen. This results in the formation of brittle intermetallic compounds enriched with titanium at the periphery of the weld zone. 相似文献
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使用光纤激光器对TC4钛合金进行了水下湿法激光焊接试验,通过在TC4表面预置焊接辅助剂实现了增加水下湿法焊接熔深的同时对焊缝进行保护的目的. 对焊缝的微观组织和力学性能进行了分析,结果表明,预置焊接辅助剂后,焊缝熔深增大,焊接阈值增加,焊缝中裂纹减少. 焊缝中心主要由初生α和马氏体组织α'相组成,在熔池底部还保留有粗大的β晶界,焊缝由于水的急冷作用出现了淬硬组织,显微硬度远高于TC4母材. 水下焊接拉伸试验试件均断裂在焊缝处,焊接接头平均抗拉强度值为439 MPa,呈现为脆性断裂. 相似文献
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Joung Soo Kim Chin-Man Chung Sung-Hoon Baik Sang-Bae Lee 《Metals and Materials International》2011,17(1):77-82
A laser-surface melting method was studied with the aim of increasing resistance to intergranular corrosion of welded SUS
304 stainless steel. An Nd:YAG laser beam at a laser beam size of about 1 mm and power of 170 Wm was employed and the laser
power density was varied to optimize the depth of the laser melted layers. The microstructures of TIG welded and laser-surface
melted regions were measured via optical, scanning electron, and transmission electron microscopy. In addition, a comparative
evaluation of the intergranular corrosion properties of as-TIG welded and as-LSM surfaces of the SUS 304 weld was carried
out using a doubleloop electrochemical potentiodynamic reactivation(DL-EPR) polarization method in a 1 L aqueous solution
of 0.5 M H2SO4 and 0.01 M KSCN. According to the test results, the maximum melted depth was obtained at a beam scan rate of 600 mm/min and
laser power density of 20 J/mm2. The laser-surface melted (LSM) region was observed to have a very fine, homogenous, and cellular microstructure compared
to that of the TIG welded region. Grain growth in the laser-surface melted region from the substrate occurred epitaxially.
The absence of Cr depletion along the grain boundary in the LSM region, which would result in increased resistance to intergranular
corrosion of the welded SUS 304, was confirmed using an energy dispersive X-ray spectroscope attached to the electron microscope. 相似文献
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Development of the active flux in superalloy laser welding and the effect on the weld formation
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In this study, adopting uniform design method established a mathematical model to prepare multi-element active flux.GH4169 superalloy plates were welded by the Nd: YAG laser equipment with the prepared active flux.The results show all kinds of fluxes increase the depth to width ratio and the multi-component systems are more significant.The largest increment of the weld depth to width ratio is 159%, obtained by using of the F12 series flux.It is proved that by using of the active flux to increase the depth to width ratio of micro laser welding is feasible. 相似文献