共查询到19条相似文献,搜索用时 390 毫秒
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在1 230~1 260 ℃温度范围内进行了T91钢管的加压瞬间液相连接,利用电子探针研究了焊接温度对接头组织、成分的影响.结果表明:随着连接温度的提高,合金元素在接头区扩散加剧,接头组织趋于均匀化,但在1 260℃的连接温度下,接头区出现孔洞.采用先加热到1 260℃短时保温再降至1 230℃长时保温的双温加热模式,不仅可减少焊缝区的缺陷,而且可消除连接界面,实现无缝连接.接头拉伸时在母材断裂,弯曲180°不断,性能达到母材水平.另外,与钎料压力焊接头相比,加压瞬间液相连接接头变形小,两连接管具有很好的同轴度. 相似文献
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采用BNi2和Fe78Si9B13非晶合金箔作为中间层,对SIMP钢管进行三温工艺瞬时液相(TLP)扩散焊接,研究了不同等温凝固工艺参数(温度1 230,1 240℃;时间180,240s;压力8,9MPa)下接头的显微组织和力学性能。结果表明:等温凝固温度的升高或时间的延长均可以促进降熔元素的扩散,减少焊缝组织中脆硬相的生成,从而提高接头的抗拉强度、降低焊缝的显微硬度;较佳的等温凝固工艺参数为温度1 240℃、时间240s、压力9MPa,采用该参数焊接后接头组织为均匀马氏体,焊缝组织与两侧母材组织的差异很小,抗拉强度最高,为794MPa,拉伸断裂方式为韧性断裂。 相似文献
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分别采用瞬时液相扩散焊双温及三温工艺对T91钢管进行了焊接,采用扫描电镜、能谱仪、电子万能力学试验机、摆锤冲击试验机及弯曲试验机等研究了接头的显微组织、元素分布、力学性能等。结果表明:2种工艺下T91钢接头的成形质量均较好;双温工艺下接头焊缝近似直线,接头有钎焊特征,焊缝处镍元素富集导致黑色脆性相的生成;三温连接接头焊缝呈曲线状,镍元素得到均匀化扩散,接头的组织、成分与母材的相似;三温工艺下接头的抗拉强度为660MPa,冲击功为25.7J,三点弯曲180°而不裂,力学性能比双温工艺下的有显著提高;双温工艺下接头的断裂形式为韧-脆性混合断裂,三温工艺下的为典型的韧性断裂。 相似文献
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本文对重庆钢铁公司研制的15MnNi钢进行了焊条选择、焊接、焊后热处理等试验。找出各种参数对15MnNi钢焊接接头性能(特别是低温韧性)的影响。结果表明,采用TH227焊条,以小的焊接热输入量施焊并经适当的SR处理,所获得的焊接接头能满足-40℃使用的要求。 相似文献
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B. Wang S. S. Jiang K. F. Zhang 《The International Journal of Advanced Manufacturing Technology》2013,65(9-12):1779-1784
Pulse current auxiliary transient liquid-phase (TLP) diffusion bonding of SiCp/2024Al composite sheet was investigated at 580 °C using mixed Al–Cu–Ti powder interlayer. The optimal process parameters were applied as follows: pulse current density of 1.15?×?102 A/mm2, pressure of 0.5 MPa, vacuum of 1.3 ×?10?3 Pa, and bonding time from 15 to 60 min. The bonding quality is evaluated by microstructure characterization and mechanical properties of the joints. The mechanism of pulse current auxiliary TLP diffusion bonding process is analyzed. The results indicated that the dense joints without cavity consisted of the Al-based solid solution, pure Ti, Al2Cu, and TiAl3 intermetallic phase. Microhardness of joints was obviously higher than Cu diffusion zone and substrate materials zone. The shear strength of the joints monotonically increased with bonding time. The maximum value exceeded 154.1 MPa in bonding time of 60 min. Pulse current generated Joule heat, high-temperature spark plasma, and electromigration, which guarantee the feasibility of bonding process and high-quality joint. 相似文献
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以管道感应加热瞬时液相扩散焊新工艺为引导,叙述了开放式管道感应加热瞬时液相扩散焊接工艺的特点及优势,对开放式瞬时液相扩散焊接机的组成、节能效果及本焊接设备的开发研制过程进行了描述,并对新型开放式瞬时液相扩散焊接工艺及设备的应用前景进行了分析。 相似文献
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Meng Hua Wei Guo Hang Wai Law John Kin Lim Ho 《The International Journal of Advanced Manufacturing Technology》2008,37(5-6):504-512
Aluminum matrix composite SiCp/A356 was welded by half-transient liquid Phase diffusion welding (HTLPDW) with a Cu interlayer. The effects of welding parameters
and interlayer thickness on the properties of the welded joint were investigated, and the optimal welding parameters were
subsequently put forward. The relationship between the tensile strength of the joint and the microstructure was studied by
analyzing the microstructure of joint using a scanning electron microscope (SEM) and an electron probe micro-analysis (EPMA).
Results confirmed the success of welding aluminum matrix composite SiCp/A356 utilizing HTLPDW method with a Cu interlayer. Shorter welding time was a prominent characteristic of HTLPDW as compared
with conventional transient liquid phase (TLP) diffusion welding. Furthermore, its welded joints had a tensile strength almost
72% of its parent matrix composites, evidently signifying the suitable application of half-transient liquid phase diffusion
welding in welding composite engineering structures. 相似文献
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针对铁素体不锈钢焊接HAZ晶粒易长大的问题,提出采用小热输入的CMT焊接工艺。通过分析接头HAZ的显微组织、显微硬度和冲击性能,探讨了4003铁素体不锈钢焊接接头HAZ组织和性能,并与常规MIG焊焊接接头试样的组织、性能进行对比。试验结果表明:采用CMT焊接工艺获得的接头HAZ粗晶区宽度为460μm,明显窄于MIG焊接接头的粗晶区宽度545μm;CMT接头强度与MIG焊接接头显微硬度值相近,但CMT接头HAZ冲击韧性较MIG焊接接头试样提高了16.28%。 相似文献
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拉拔式摩擦塞补焊是一种固相连接技术,具有接头强度高,焊后残余应力和变形小等优点,在航天领域具有潜在的应用前景。研究轴向拉力对2A70铝合金拉拔式摩擦塞焊焊接成形及接头性能的影响,并分析焊接缺陷、微观组织及断口形貌特征。结果表明,轴向拉力在20~30 kN范围内能够得到良好的焊缝成形;轴向拉力为20 kN时,结合界面存在未焊合缺陷;轴向拉力提高至22 kN及以上,未焊合缺陷完全消除;轴向拉力提高至28~30 kN时,塞棒与母材形成完好的冶金结合,焊接接头的抗拉强度可达到376 MPa,接头系数为83.6%。当轴向拉力较低时(22~25 kN),结合界面上易出现弱结合缺陷,微观特征为沿结合界面断续分布的微孔,可导致接头抗拉强度和断后伸长率下降;焊接接头中,塞棒侧热影响区硬度值最低,分析表明该区域的晶粒形态和尺寸未发生明显变化,但θ'相部分溶解,θ相发生粗化,导致局部强度下降;断口形貌显示,在优化参数下断口呈现韧性特征。研究结果可为铝合金拉拔式摩擦塞补焊工艺及机理分析提供借鉴和参考价值。 相似文献
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采用硼酸铝晶须增强的Ag-18Cu复合钎料对氧化锆增韧氧化铝陶瓷进行钎焊,根据钎料润湿和铺展性能的变化得出合理的晶须加入量。通过扫描电镜进行钎焊接头组织形貌观察,并通过能谱仪进行元素分析,研究钎焊接头微观结构及晶须对接头的强化机理。在改变焊接温度、焊接时间等工艺参数的情况下,进行多次钎焊试验。通过微机控制电子万能试验机及专用夹具,对钎焊后的试验件进行抗剪强度测试。通过测试得到工艺参数对钎焊接头组织及力学性能的影响规律,进而得出最优的工艺参数。 相似文献
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Naci Kurgan 《The International Journal of Advanced Manufacturing Technology》2014,71(9-12):2115-2124
In the present study, diffusion bonding of aluminium alloy (AA7075) sheet materials which are used especially in the automobile and aerospace industry has been investigated at temperatures of 425 and 450 °C and pressures of 2 and 3 MPa for 180 min in argon atmosphere. The microstructural and mechanical properties of bonding have been characterized with different welding parameters such as bonding temperature and pressure. The microstructure was characterized by light optical microscope, scanning electron microscope and energy dispersive spectroscopy, while the mechanical properties were determined by tensile-shear tests and microhardness tests. The results obtained are discussed from both the microstructural and mechanical points of view. It was observed in the microstructural investigations that the interfacial oxide layer decreased with increasing of the bonding temperature and pressure. The maximum shear strength was found to be 131 MPa for the Al 7075 sample bonded at 450 °C and 3 MPa for 180 min. It is shown that in certain extent, the bonding temperature and bonding pressure have great effect on the joint shear strength. With the increasing of bonding temperature and pressure, the shear strength of the joints increases due to diffusion of atoms in the interface. The strength achieved after bonding were dependent on interface grain boundary migration and on grain growth during the bonding process. The maximum hardness value of the Al 7075 sample bonded at 450 °C, 3 MPa for 180 min is 92.5 HV0.2. Increasing hardness with increasing temperature can be attributed to the formation of metallic bond at high temperatures and pressures. 相似文献