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研究了某喷管壳体对接环缝的真空电子束焊工艺,该工艺主要包括接头形式设计、工装夹具设计以及焊接工艺参数的确定。通过一系列工艺试验得出了喷管壳体对接环缝的电子束焊最优工艺参数为:加速电压50~60 k V,聚焦电流1.85 A,束流强度60 m A,焊接速度1 200 mm/min。 相似文献
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在铝合金与钢之间添加Ag中间层后进行电子束焊接实验。其他参数固定的情况下,对电子束作用位置不同时的焊缝成形、接头组织和力学性能进行分析。结果表明:随着电子束斑点从银-钢对接面向银侧偏移距离的增大,焊缝成形明显得到改善,接头中的气孔缺陷消失。在银-铝对接面形成由Ag2Al和Al共晶组成的过渡层,过渡层随着偏束距离的增大而变窄且不连续。当偏束距离过大时,在银-钢界面上形成FeAl和FeAl3两种化合物层。当电子束最佳偏束距离为0.2mm时,接头强度最高达193MPa,为铝母材的88.9%,此时断裂发生在银-钢界面上。 相似文献
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电子束焊已在机械行业、航空工业得到了广泛应用,尤其是航空重要承力件和传动件,均是电子束焊件,这些构件的母材均是合金结构钢,它们具有良好的工艺性能并可获得较高的强度,本文介绍几种典型牌号合金结构钢的电子束焊工艺。 相似文献
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采用电子束选区熔化技术制备Nb521合金,研究其致密化成形工艺。通过对成形试样的组织、物相、显微硬度、室温拉伸性能的检测与分析,探讨了电子束选区熔化成形Nb521合金的机理。结果表明,电子束选区熔化成形过程中,电子束熔化电流及速度的合理匹配,是得到表面质量及内部质量优异的成形样品的基础;电子束能量密度为340 J/mm3时,样品的密度达到8.78~8.79 g/cm3;Nb521合金显微组织沿沉积方向呈柱状晶,晶粒沿(200)晶面有较强的择优生长取向;成形样品中除Nb基体相外,还存在少量的Nb2C与ZrC碳化物析出;样品室温抗拉强度达到384 MPa,屈服强度为307 MPa,断后延伸率为16.5%;显微硬度处于1 500~1 700 MPa之间,无各向异性。 相似文献
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使用装备了可编程序控制器的电子束焊接设备,研究新型铝基复合材料TiB2/ZL101的焊接性。在合适的工艺参数和扫描频率下,通过电子束焊接方法可以得到无缺陷的焊缝,焊后增强相TiB2在焊缝中分布均匀,未出现偏析现象。对焊缝进行拉伸性能测试,均在母材处发生断裂,电子束焊接得到了较高的焊缝强度;通过对焊缝进行磨损测试,焊缝的抗磨损性能得到了显著的提升。研究表明,采用电子束焊接方法可以有效地完成新型铝及复合材料TiB2/ZL101的焊接。 相似文献
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对PDC钻头钎焊工艺存在的问题,提出用真空扩散焊接代替钎焊制造PDC钻头.采用正交试验法,通过极差分析和方差分析,研究了PDC钻头真空扩散焊接温度、焊接压力和焊接时间等工艺参数对焊接接头抗剪强度的影响,以得出其扩散焊接的最佳工艺参数.结果表明,当采用焊接温度700℃、焊接压力150 MPa和焊接时间6h的参数组合时,可获得高强度高致密性的焊接接头,其接头抗剪强度≥500MPa. 相似文献
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Ugur Ozsarac 《Journal of Materials Engineering and Performance》2012,21(5):748-755
In this study, the electric resistance spot welding process was applied to zinc-coated steel sheets used in automotive industry.
Spot welding parameters namely, electrode form, electrode material, and electrode force were stayed constant, and welding
current and welding time have been changed to detect the optimum welding parameters for maximum joint strength. Using 4, 5,
6, 7, and 8 kA welding currents and 5, 10, 15, 20, and 25 cycles welding times 1.0-1.0 mm sheets were spot welded to prepare
samples. These spot-welded joints were then exposed to uniaxial tensile test, and tensile-shear and tensile-peel forces prior
to breaking were determined. In addition, microstructures were detected by SEM and micro-hardness was measured from different
regions of resistance spot-welded samples and recommendations showing the optimum welding parameters were given to users. 相似文献
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对5mm厚的1050-H24铝合金板材进行了双面搅拌摩擦焊接(FSW),重点研究了接头的拉伸性能和断裂部位及其影响因素。研究结果表明,一次焊接参数、二次焊接参数和焊接方向对双面FSW接头的拉伸性能和断裂部位有不同程度的影响。一次焊接参数的影响较小,而二次焊接参数的影响显著并且存在最佳取值。同向焊接的接头强度较高且断在前进侧(AS)或后退侧(RS),而异向焊接的接头强度较低且只断在AS。在文中的试验条件下,1500r/min的旋转速度、400mm/min的二次焊速和同向焊接方式是最佳的工艺组合,接头最高强度达到母材强度的78%。 相似文献
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The electron beam welding-brazing being used to join 5A06 Al alloy to TC4 Ti alloy decreases the formation of brittle intermetallic compound. Experiments were carried out to study the influence of electron beam welding parameters on the tensile strength of welds, based on an orthogonal test and analysis method. The welding parameters include beam current, welding speed, scanning figure, scanning frequency, figure size, beam offset and focus current. The optimum parameters for 3 mm 5A06 Al alloy and 2 mm TC4 alloy were as follows: acceleration voltage was 60 kV, beam current was 11 mA, welding speed was 600 mm/min, focus current was 0 mA, scan figure was ○, scanning frequency was 1 000 Hz and beam offset was 0.5 mm. The results show that the joints were with good appearance and quality welded by the optimum parameters. The successful joints could be gained and the maximum tensile strength of Al/Ti dissimilar alloy joints could be up to 222.61 MPa using electron beam welding-brazing. 相似文献
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《Science & Technology of Welding & Joining》2013,18(4):362-368
AbstractPulsing of the welding current is one approach for refining the fusion zone microstructure in materials joined by fusion welding. The effect of current pulse frequency on weld bead microstructure, tensile strength, and hardness in joining of powder metallurgical steel preform sheets to wrought copper was studied. Considering weld strength as the quality characteristic in the selection of process parameters, the Taguchi method is used to analyse the effect of each process parameter individually and of their interaction on weld strength, and subsequently to determine the process parameters leading to optimum weld strength. The application of pulsed current causes iron dendrites to become more equiaxed and uniformly distributed owing to dendrite fragmentation. Further, there was an optimum frequency range over which the microstructural refinement was maximal. The same optimum frequency range corresponded to maximum tensile strength. Enhanced fluid flow and reduced thermal gradients are thought to be responsible for refining the solidification structure and the resulting stronger welds. 相似文献
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采用一种新型复合焊接工艺——电阻塞焊对1.5 mm等厚TRIP980高强钢/SPCC低碳钢板进行焊接,利用正交试验优化其焊接参数,随后增加焊前预热,分析对比无预热和焊前预热两种条件下较优焊接参数时接头的力学性能及组织、硬度特点.结果表明,各焊接参数对接头的拉剪载荷影响程度由大到小依次为焊接电流、填充物直径、焊接时间及电极力;在电极头端面直径为8 mm的条件下,填充物直径为5.5 mm时的接头力学性能优于其它直径;相同焊接参数时,焊前预热塞焊接头的拉剪载荷比无预热提高7%以上;两种条件下较优焊接参数时,焊前预热塞焊接头的熔核偏移量小于无预热,熔核和熔合区的硬度比无预热时有所下降,熔合区脆硬马氏体组织比无预热少;焊前预热塞焊接头断口为韧性断裂,无预热塞焊接头断口为脆性断裂;其主要机理是,预热减小了熔核区金属过热倾向,使熔核扩展均匀,熔合区脆硬组织减少,有利于接头强度的提高. 相似文献
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对10 mm厚7075铝合金板材进行脉冲变极性等离子弧焊,研究了焊接电流和离子气流量的变化对焊缝成形系数的影响规律,确定了较优的焊接参数并获得了成形良好的焊缝,对该焊接接头力学性能进行分析. 结果表明,焊缝成形系数随着焊接电流的增大先减小后增大,随着离子气流量增大逐渐减小,较佳的焊缝成形系数区间为1.1 ~ 1.3,焊接电流比离子气流量对焊缝成形的影响更大. 当脉冲焊接电流为250 A/290 A,离子气流量为2.0 L/min时焊缝形貌较佳,接头焊缝区为树枝状晶,焊缝处的抗拉强度为397.9 MPa,约为母材的67.5%,焊缝的性能较好. 相似文献
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在奥氏体不锈钢与铜合金异种材料摩擦焊接过程中,采用响应面方法优化摩擦焊接工艺参数,以获得抗拉强度最大和界面硬度最小的焊接接头。采用三因素、五水平中心复合正交矩阵来确定实验条件。得到20个焊接接头,测定了焊接接头的抗拉强度和界面硬度。采用方差分析(ANOVA)方法来确定起显著作用的、主要的及相互作用的参数,使用回归分析得到经验关系模型。用设计专家软件构造响应图和等高线图来优化摩擦焊接工艺参数。用得到的经验关系模型可以有效地预测焊接接头的抗拉强度和界面硬度,其置信水平达95%。从形成的等高线图可以得到所需的摩擦焊接的最佳条件。 相似文献
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《Science & Technology of Welding & Joining》2013,18(6):450-454
AbstractThe friction stir welding (FSW) of 1050 - H24 aluminium alloy was performed to investigate the mechanical properties of the joints and determine the optimum FSW parameters. The mechanical properties of the joints were evaluated via tensile tests. The experimental results showed that a distinct softened region located at the weld and heat affected zones occurred in the joints. The degree of softening and tensile properties of the joints are significantly affected by the welding process parameters, such as welding speed and rotation speed. The optimum FSW parameters can be determined from the relations between the tensile properties and the welding parameters, and the maximum tensile strength of the joints is equivalent to 80% of that of the base material. When the welding parameters deviate from the optimum values, a crack like defect or significant softening is produced in the joints, thus the tensile properties of the joints deteriorate and the fracture locations of the joints change. All these results can be explained by the hardness distributions and welding defects in the joints. 相似文献
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S. M. Darwish S. D. Al-Dekhial 《International Journal of Machine Tools and Manufacture》1999,39(10):1589
The present paper reports experimental investigations on the spot welding of commercial aluminium sheets. Experiments were carried out to study the influence of spot welding parameters (welding current, welding time, electrode force and sheet thickness) on the strength of spot welded aluminum sheets with commercial purity. Experiments were planned on the basis of response surface methodology (RSM) technique. The mathematical models (failure load and nugget area) correlating process parameters and their interactions with response parameters have been established. These models have been used in selecting the optimum process parameters for obtaining the desired spot welding quality at the least possible consumed power. 相似文献