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在对钛合金激光穿透焊焊缝成形特征分析的基础上研究了激光焊主要工艺参数对焊缝成形的影响,同时对比研究了CO2激光和YAG激光穿透焊时焊缝成形的差异。研究结果表明,在穿透焊条件下,CO2激光和YAG激光焊接钛合金焊缝都具有钉形和近X形两种典型的截面形貌。焊缝成形与焊接热输入及激光功率密度有密切联系。随焊接热输入和激光功率密度的增大,焊缝截面由钉形向近X形转变。在采用同样工艺规范获得近X形焊缝成形时,YAG激光焊缝的对称度显著高于CO2激光焊缝。通过调整激光功率、焊接速度和离焦量等激光焊工艺参数,可以对焊缝成形进行有效控制,提高焊接接头质量。 相似文献
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在对钛合金激光穿透焊焊缝成形特征分析的基础上研究了激光焊主要工艺参数对焊缝成形的影响 ,同时对比研究了CO2 激光和YAG激光穿透焊时焊缝成形的差异。研究结果表明 ,在穿透焊条件下 ,CO2 激光和YAG激光焊接钛合金焊缝都具有钉形和近X形两种典型的截面形貌。焊缝成形与焊接热输入及激光功率密度有密切联系。随焊接热输入和激光功率密度的增大 ,焊缝截面由钉形向近X形转变。在采用同样工艺规范获得近X形焊缝成形时 ,YAG激光焊缝的对称度显著高于CO2 激光焊缝。通过调整激光功率、焊接速度和离焦量等激光焊工艺参数 ,可以对焊缝成形进行有效控制 ,提高焊接接头质量。 相似文献
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分区扫描策略对选区激光熔化成形件的表面质量有重要影响,而目前分区尺寸对成形件表面结构的影响规律尚不清晰。为进一步提高选区激光熔化成形带支撑悬垂结构的表面质量及尺寸精度,以带支撑方形悬垂结构为研究对象,结合数值模拟与成形试验从表面原始轮廓的形状误差、波纹度与表面粗糙度三个不同波距的表面结构进行研究。研究结果表明:随着分区尺寸的减小,成形件表面边缘的翘曲高度逐渐降低,但相邻分区之间的轮廓起伏程度逐渐增加,成形件截面轮廓的形状误差与表面粗糙度得到改善,波纹度呈现出增大趋势,使成形表面形貌呈先改善后降低趋势。形状误差、波纹度与表面粗糙度随分区尺寸的减小变化趋势并不一致,分区尺寸过小会导致热累积现象明显,波纹度增加。在减小分区尺寸的同时适当降低激光能量输入,能有效改善表面形貌。为提高SLM成形带支撑悬垂结构的尺寸精度和表面形貌提供了理论基础。 相似文献
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激光烧结金属陶瓷成形探讨 总被引:1,自引:0,他引:1
利用激光直接成形出高质量的金属、陶瓷及金属陶瓷复合材料零件是激光选择性烧结的最终目标。本文对激光烧结成形金属以及陶瓷材料进行了探讨与分析,对其中出现的问题作了初步的分析。 相似文献
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基于等离子弧焊的Ti-6Al-4V快速成形工艺参数研究 总被引:2,自引:0,他引:2
研究了基于等离子弧焊的钛合金零件直接金属快速成形方法。采用正交试验和成形温度对比测试的方法,研究了脉冲电流强度、占空比等6个重要工艺参数对成形轨迹截面宽高比的影响规律。结果表明:脉冲电流强度、占空比、送丝速度、工作台速度对宽高比的影响非常显著,等离子气流量对宽高比的影响显著,而脉冲频率的影响不显著。采用获得的优化参数制作了Ti-6Al-4V零件,并进行了抗拉强度和致密度测试,结果表明其抗拉强度和致密度与激光熔覆成形件的性能相当。 相似文献
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目的提高选区激光熔化成形316L不锈钢的成形表面质量,达到高质高效成形效果。方法采用380W功率的激光进行SLM成形,对比160μm大层厚和1000 mm/s以上高速率两种工艺组合,对表面及截面缺陷形成机理进行试验研究,检测其表面形貌、致密度、微观组织、力学性能等,探索316L高质高效打印成形的工艺方法。结果选区激光熔化成形316L不锈钢主要有球化、搭接、熔池间未熔合的表面缺陷,截面具有气孔、球化、熔池间未熔合的缺陷。曝光时间对于大层厚成形截面质量影响最大,增加曝光时间会提高成形致密度;而较小的曝光时间和点距以及线间距更有利于高速率成形。在1000 mm/s高速率试验条件下,即曝光时间、点距、线间距分别为30μs、30μm、90μm时,试件致密度达到99.99%。结论高速率成形的截面质量通过工艺优化组合可达到高致密度,且通过表面重熔工艺改善表面效果明显,整体性能最优。大层厚参数打印成形虽可达到高致密度,但在表面质量方面与高速率成形参数存在较大差距。综合比较,高速率成形在保证较好表面质量的前提下可以达到高致密度。 相似文献
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Direct Metal Laser Sintering (DMLS) is a rapid manufacturing technology that is starting to be used for the manufacturing of functional components. Therefore, properties of DMLS manufactured parts must be carefully analyzed to determine if they satisfy technical requirements under fatigue conditions. 相似文献
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分析了双组元金属粉末的激光直接快速成形金属零件的机理,阐述了烧结成形过程中的一些基本特征,主要包括翘曲变形、球化效应和裂纹.从理论上讨论了激光参数、工艺参数、材料特性、烧结气氛等对成形件质量的影响. 相似文献
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Roller levelling is a complex forming process to minimize flatness imperfections and residual stresses by repeated forming of a sheet.At the Institute for Metal Forming and Metal Forming Machine Tools at the University of Hanover an analytic forming model is being developed which analyses the levelling process with sufficient precision in a shorter time than is possible with the finite element method (FEM).With this analytic forming model, the states of multiple forming under bending conditions during the levelling process can be investigated. The residual stresses and the residual bend of the sheet metal are calculated. Additionally, the forces acting on the rollers during levelling are determined. The controlling system assures setting of rollers automatically. 相似文献
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Xin Wu 《Journal of Materials Engineering and Performance》2007,16(4):418-431
A steady-state creep equation is commonly used in the analysis of superplastic forming or other elevated temperature forming
processes. However, in Hot Metal Gas Forming of tubes, the effective stress increases as tube diameter expands and wall thickness
decreases, and a steady-state creep condition does not exist. Thus, non-steady-state creep behavior of materials becomes important.
This paper presents some experimental results on transient creep behavior of a magnesium alloy, and provides an analysis on
transient creep behavior and its application in tube forming mechanics. It is verified that non-steady-state creep plays important
role in the gas tube forming at elevated temperatures.
This article was presented at Materials Science & Technology 2006, Innovations in Metal Forming symposium held in Cincinnati,
OH, October 15-19, 2006. 相似文献
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Petra Kersting Daniel Gröbel Marion Merklein Peter Sieczkarek Sebastian Wernicke A. Erman Tekkaya Eugen Krebs Dennis Freiburg Dirk Biermann Tim Weikert Stephan Tremmel Dominic Stangier Wolfgang Tillmann Steffen Matthias Eduard Reithmeier Maria Löffler Florian Beyer Kai Willner 《Production Engineering》2016,10(1):37-50
Sheet-Bulk Metal Forming (SBMF) allows the manufacture of complex parts with integrated functional form elements, such as teeth and thickened areas. Therefore, bulk forming operations are applied to sheets with initial thicknesses of 2 or 3 mm. The design and functionality of the tools are as important as the process itself. Therefore, the working group “Tools” of the Transregional Collaborative Research Centre on Sheet-Bulk Metal Forming (CRC/TR73) focuses on the optimization of the technical tool design. By varying topographies or applying tailored coatings, the friction behavior is changed to achieve a better form filling and to reduce process forces during the forming operations. In this paper, the potential of different tailored surfaces is validated by simulations and experimental studies. The tribological behavior of 14 surface microstructures is evaluated using a half-space model in order to select structures suitable for application. Those were characterized experimentally by ring-compression and pin-extrusion tests. The determined friction factors were used in a forming simulation to predict the form filling of small cavities in a flow forming operation. Furthermore, special attention is paid to the utilization of the anisotropic behavior of specific structures. The results were validated by an incremental gear forming process. 相似文献