共查询到20条相似文献,搜索用时 109 毫秒
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钛合金薄板激光和钨极氩弧焊残余应力测试研究 总被引:6,自引:1,他引:5
采用小孔释放法对钛合金薄板激光焊和钨极氩弧焊(TIG焊)的焊接残余应力进行了测试,并分析了焊接方法、焊接线能量和焊后热处理对残余应力分布规律的影响。研究结果表明:激光焊残余应力分布规律与普通熔焊方法相似,但其分布区域较窄;在热影响区内,激光焊残余拉应力值比TIG焊的约低100MPa;在焊缝及其熔合线附近,激光焊残余应力却比TIG焊的高。对于不同线能量激光焊接,线能量越大,焊缝越宽,热影响区的残余应力也越大。焊后真空热处理能降低残余应力90%。 相似文献
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Pulsed Nd-YAG Laser Welding of A SiC Particulate Reinforced Aluminium Alloy Composite 总被引:2,自引:0,他引:2
This paper examines the laser welding behaviour of a SiC particulate reinforced Al-alloy 2124 composite using a pulsed Nd-YAG laser. The influences of laser welding parameters of laser intensity, pulse duration and the beams focus position on the depth of weld penetration as well as the size of fusion zone were investigated. These investigations have led to an optimum welding condition proposed for pulsed laser welding of SiC particulate reinforced aluminium alloy composites with minimum defects. 相似文献
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目的 为了提高塑料焊接焊缝的剪切强度,满足实际生产要求.方法 采用环形光斑进行激光焊接试验,通过对激光功率、焊接速度、离焦量工艺参数进行三因素三水平正交试验,得到最佳工艺参数.结果 在最佳工艺参数条件下,即激光功率为50 W,焊接速度为150 mm/s,离焦量为5 mm时,PA66塑料焊缝最大剪切强度为21.6 MPa.焊缝切片分析结果表明,环形光斑激光焊缝的熔深均匀一致,内部无气孔产生.结论 正交试验的极差分析结果表明,对焊缝剪切强度的影响因素由主到次依次为离焦量、激光功率、焊接速度. 相似文献
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目的研究白车身顶盖与侧围激光钎焊装配尺寸控制方法,提高顶盖侧围激光钎焊焊缝装配精度,降低激光焊缺陷率。方法顶盖与侧围焊接配合形面由传统的面贴合设计更改为线贴合,降低对车身焊接合拼精度的要求;顶盖与侧围模具结构上采用整体整形及压料镶块提升零件的尺寸精度,避免因镶块交接造成的翻边面缺陷而影响激光钎焊质量;顶盖与侧围的成形焊夹具设计成y向浮动以及在激光焊夹具上设计z向夹紧功能,来实现侧围与顶盖装配间隙的调整。结果实际应用表明,侧围与顶盖激光钎焊装配尺寸得到了有效控制,满足激光钎焊的要求。结论顶盖与侧围产品的设计优化、冲压模具工艺和结构的创新和优化以及焊装焊接夹具的柔性化适配功能,可以有效保证白车身顶盖钎焊搭接部位尺寸精度。 相似文献
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Titanium materials exhibit a property profile that is just as versatile as that of steel materials. Titanium materials therefore have outstanding properties, such as excellent resistance to corrosion and high strength values at low densities, which makes them ideal for use in the chemical industry and as structural materials in lightweight construction. Due to the high affinity of titanium to atmospheric gases at increased temperatures above 500 °C, titanium components have to be welded in a sophisticated process under inert shielding gas by TIG welding or by an electron beam in a vacuum. A novel innovative laser beam welding process using a pulsed laser with free pulse shaping will be presented here with which oxidation‐free titanium weld seams with excellent mechanical and technological properties can be produced. For this low heat welding process, the otherwise commonly used inert gas covering can be substituted with a shielding gas nozzle. The process‐specific low heat input and the resulting low energy input per unit length both have a positive effect on the microstructure and thus on the mechanical properties. This welding process offers both technological and economical advantages over the processes used up until now, particularly for the machining of complex components and for series production. 相似文献
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为实现直径为0.1 mm微孔的良好封接,采用低功率脉冲激光对0.40 mm厚的工业纯钛(CP-Ti Grade 1)进行了封焊,采用扫描电镜、显微硬度计及光学显微镜,研究了激光功率对焊缝表面成形、焊接接头横截面形貌和显微硬度的影响规律,分析了接头的微观组织结构.结果表明:当激光功率不低于19.2 W时,微孔可以实现完全封接,且熔核直径随着激光功率的增大而增大,但随着激光功率增大,焊缝凹陷和烧蚀现象越加严重;当激光功率增大时,焊缝表面显微硬度呈上升趋势,激光功率为19.2 W时,焊缝成形良好,且最大显微硬度值可以达到290 HV;焊缝中心微观组织为针状α、锯齿状α以及板条状α晶,焊缝上边缘为锯齿状α晶,而焊缝下边缘为细小的锯齿状α和针状α晶. 相似文献
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目的 针对汽车高强钢SG1000焊接接头恶化等问题,研究了SG1000激光复合焊接的力学性能。方法 选用等强匹配焊丝MG90-G对高强钢SG1000进行激光复合焊接,对焊接接头进行拉伸和低温冲击韧性试验,并结合扫描和硬度监测等手段对焊缝组织和断口形貌进行分析。结果 由于激光的预热作用,高强钢SG1000激光复合焊接成形件的焊缝美观,焊接过程稳定可靠,焊接熔池深度较大,有效改善了传统焊接的咬边、飞溅、气孔等缺陷。焊缝组织主要由板条马氏体和奥氏体晶粒组成,热影响区的过热区内部板条马氏体和奥氏体晶粒比较粗大,而焊接母材主要为细小的板条马氏体和奥氏体晶粒。焊接拉伸断口主要为细小且较浅的韧窝,且韧窝底部存在第二相粒子及夹杂物,焊接拉伸断口断裂于热影响区且微观形貌为韧性断裂;冲击微观形貌主要由准解理小平面及河流花样组成,且存在一定数量大小不一的韧窝交错分布,焊接冲击断口断裂于热影响区且微观形貌也为韧性断裂。结论 焊缝热影响区的晶粒比非热影响区的晶粒粗大,拉伸和冲击断裂均发生于热影响区;随着激光功率的增大,复合焊接接头的力学性能呈现逐渐增强的趋势;随着焊接速度的增大,复合焊接接头的力学性能呈现先增强后削弱的趋势。高强钢SG1000激光复合焊接最佳工艺参数如下:激光功率为9.5 kW,焊接速度为0.8 m/min,对应屈服强度为1 072 MPa,抗拉强度为1 175 MPa,断裂伸长率为13.5%,冲击断裂吸收的能量为30.8 J、焊缝中心显微硬度为342 HV。 相似文献
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With the wide application of aluminum alloys in automotive, aerospace, and other industries, laser welding has become a critical joining technique for aluminum alloys. In this review, the research and progress in laser welding of wrought aluminum alloys are critically discussed from different perspectives. The primary objective of the review is to understand the influence of welding processes on joint quality and to build up the science base of laser welding for the reliable production of aluminum alloy joints. Two main types of industrial lasers, carbon dioxide (CO2), and neodymium-doped yttrium aluminum garnet (Nd:YAG), are currently applied but special attention is paid to Nd:YAG laser welding of 5000 and 6000 series alloys in the keyhole (deep penetration) mode. In the preceding article of this review (part I), the laser welding processing parameters, including the laser-, process-, and material-related variables and their effects on welding quality, have been examined. In this part of the review, the metallurgical microstructures and main defects encountered in laser welding of aluminum alloys such as porosity, cracking, oxide inclusions, and loss of alloying elements are discussed from the point of view of mechanism of their formation, main influencing factors, and remedy measures. The main mechanical properties such as hardness, tensile and fatigue strength, and formability are also evaluated. 相似文献
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目的 研究火箭发动机关键部件过滤器壳体的改良加工方案,以替代传统的化学铣切、手工氩弧焊等工艺,提高产品尺寸精度和生产效率。方法 改良加工方案采用激光切割、激光焊接等技术,利用激光切割精度高、成形快的优点,实现镂空区域的一次成形,避免化铣周期长、易于产生飞边且打磨困难的问题;利用激光焊接热输入量低、焊接变形少的特点,使镂空状态下单边宽度3.5 mm的筋条焊接成为可能。结果 通过设置合理的工艺参数,可以有效保证产品尺寸精度并控制焊接变形,提高生产效率。结论 使用该工艺方法已成功制备了产品,并经过了发动机试车考核。 相似文献
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Research and Progress in Laser Welding of Wrought Aluminum Alloys. I. Laser Welding Processes 总被引:1,自引:0,他引:1
With the wide application of Al alloys in automotive, aerospace and other industries, laser welding has become a critical joining technique for aluminum alloys. In this review, the research and progress in laser welding of wrought Al alloys have been critically discussed from different perspectives. The primary objective of this review is to understand the influence of welding processes on joint quality and to build up the science base of laser welding for the reliable production of Al alloy joints. Two main types of industrial lasers, carbon dioxide (CO2) and neodymium-doped yttrium aluminum garnet (Nd:YAG), are currently applied but special attention is paid to Nd:YAG laser welding of 5000 and 6000 series alloys in the keyhole (deep penetration) mode. In this part of the review, the main laser welding processing parameters including the laser-, process-, and material-related variables and their effects on weld quality are examined. In part II of this article in this journal, the metallurgical microstructures and main defects encountered in laser welding of Al alloys such as porosity, cracking, oxide inclusions, and loss of alloying elements are discussed from the point of view of mechanism of their formation, main influencing factors, and remedy measures. In part II, the main mechanical properties such as hardness, tensile, and fatigue strength and formability are also discussed. 相似文献
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船舶用钛合金焊接接头要求具有较好的抗冲击性能和抗疲劳性能,针对较大壁厚结构件,一般的焊接技术效率低且焊接质量较难保证,真空电子束焊接技术在这方面具有优势。本文综述了钛合金电子束焊接的特点,对其在船舶应用的前景,尤其是在大厚板焊接、冲击性能和疲劳性能等方面的优异表现进行了介绍,船舶用钛合金厚板焊接的长服役寿命可靠性是采用电子束焊接结构制造的根本目的。 相似文献
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The paper presents bounded volume heat sources and the corresponding functional-analytical expressions for the temperature field. The power density distributions considered here are normal, exponential and parabolic. The sources model real heat sources like the welding arc, laser beam, electron beam, etc., the convection in the weld pool as well as the latent heat due to fusion and solidification. The parameters of the heat source models are unknown a priori and have to be evaluated by solving an inverse heat conduction problem. The functional-analytical technique for calculating 3D temperature fields in butt welding is developed. The proposed technique makes it possible to reduce considerably the total time for data input and solution. It is demonstrated with an example of laser beam welding of steel plates. 相似文献
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The pneumatic system conducts the pressurized hot air from the engine to the environmental systems of the aircrafts. In-service failures of arc-welded pneumatic parts have driven further developments of laser beam welding as an alternative method. Here, a fiber laser with 2 kW power had been employed to weld commercial purity titanium tubes with 0.5 mm wall thickness and 50 mm diameter. For comparison purposes, semiautomatic TIG welding was realized. The chosen parameters speed and laser power for laser welding were 200 W–2 m/min and 250 W–3 m/min. The laser welded tubes presented 1 mm wide weld beads composed by partially twinned α-Ti grains. The TIG welded tubes showed 5 mm wide beads composed by acicular α-grains. These observed differences had been associated with the cooling rates, which are ten times higher in the laser case. Both laser and TIG welded tubes were cycled 44,000 times in a pneumatic bench at 350 °C without failures or cracks that could release the internal pressure. After the pressurization tests, the tubes were tested for tensile and fatigue resistance. The yield stresses, tensile strengths and total elongation did not change comparing base material, TIG welded and laser welded cases. The condition 200 W–2 m/min presented superior fatigue resistance values compared to other welding conditions, and could be considered similar to the tubes in the unwelded condition. The microstructural and mechanical results had shown that the current laser technology can replace, with advantages, the arc welding for the joining of the titanium tubes. 相似文献