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采用等离子弧工艺,对槽形表面结构进行强化处理,研究工艺参数对镀层结构和性能的影响,并分析了其界面强化机理.结果表明,等离子弧强化热输入量对镀层质量有明显的影响,热输入量过小难以实现镀层与基体的冶金结合,过大则引起"过加热",使镀层附近晶粒长大严重,降低镀层附近硬度及强化质量.采用合理的阴线、阳线、倒转侧面制定合理的强化工艺规范,可取得最佳强化效果.等离子束处理镀层界面成分变化分析结果表明,镀层中的Cr与基体Fe发生相互扩散,界面基体组织发生马氏体相变,使镀层与基体之间形成相变硬化层,达到冶金结合,改善了基体微观组织结构. 相似文献
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以层流等离子弧作为热源对共析钢进行表面淬火,通过等离子表面淬火热传导的理论分析,对等离子弧扫描速度对硬化层最大硬化深度的影响进行研究。并利用电子扫描显微镜、显微硬度计等试验手段,研究了淬火硬化层的显微组织和力学性能。结果表明:层流等离子弧扫描速度越快,淬火硬化层最大硬化深度越小。得出等离子弧扫描速度与淬火硬化层最大硬化深度之间的关系,并且与实验结果相吻合。淬火硬化层组织为板条状马氏体和针状马氏体,淬火硬化层与基体的界面组织为珠光体和隐针马氏体,基体组织为珠光体。淬火硬化层硬度由共析钢基体的350 HV提高到900~1000 HV。 相似文献
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等离子弧焊接在中厚板焊接领域具有重要的应用前景.自主设计搭建了气流再压缩等离子弧焊接系统,开展了气流再压缩等离子弧焊接新工艺试验研究.通过焊接过程监测系统分析焊缝成形,温感扫描图可以比较准确的反映实际焊缝成形.针对8 mm厚的304不锈钢,焊接电流为150 A时,常规等离子弧焊接熔深为6.53 mm;气流再压缩等离子弧焊接可以完全熔透工件,且正面焊缝和背面焊缝成形良好.结果表明,相同电流条件下,与常规等离子弧焊接相比,气流再压缩等离子弧焊接电弧电压升高;气流再压缩等离子弧焊接可以提高焊接熔透能力. 相似文献
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焊接过程的准确检测是实现高效优质焊接的基础。实现等离子弧焊接过程的多信号检测对于指导等离子弧焊接工艺具有重要意义。文中搭建了基于多信号检测的等离子弧焊接平台,该等离子弧焊接平台包括等离子弧焊机和焊枪系统、机械运动机构、视觉检测系统、焊接过程监测系统、计算机控制系统等;通过视觉检测系统拍摄了等离子弧焊接电弧形态,测量出了喷嘴出口处的电弧直径与工件上表面电弧直径比值为0. 64,证实了等离子弧焊接电弧挺度高,发散程度小;通过焊接过程监测系统,拍摄了焊缝温感扫描图,在线实时监测了等离子弧焊接焊缝成形,结果表明温感扫描图可以比较准确地反映等离子弧焊接的实际焊缝成形。 相似文献
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X.M.Fan J.W.Huang K.H.Wang Q.Liu 《金属学报(英文版)》2005,18(3):289-294
The technology of plasma arc was used to modify the interface adhesion between chromium coating and steel substrate. The interface microstructure was studied as a function of plasma arc processing parameters. Microstructure analysis was performed by optical microscopy, scanning electron microscopy and electron probe. The microhardness distribution along the depth of a cross-section of the chromium coating and the substrate was measured. The results show the energy density of transferred plasma arc is obviously higher than plasma non-transferred arc. The molten interface wasbetween chromium coating and steel substrate obtained by plasma transferred arc. Interfaces between chromium coating and steel substrate can be divided by plasma non-transferred arc into three classes: non-molten, a little molten and molten. Good interface bonding was obtained by proper process parameters. The microhardness of chromium coating decreases with increasing energy density of plasma arc. 相似文献
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采用超音速等离子喷涂技术在45CrNiMoVA钢表面制备了MoW合金涂层,测试了涂层结合强度。利用电阻仪测试了涂层的导电性,用高压电弧装置对MoW涂层进行了大气环境不同放电电流的电弧烧蚀试验。通过场发射扫描显微镜(SEM)、电子能谱仪(EDS)分析了涂层组织,使用X射线衍射仪测试了涂层相组成。结果表明:MoW涂层与基体结合良好,导电率为6.12%IACS。W使涂层导电率有所降低;孔隙率是涂层导电性能较低的主要原因之一。随着放电电流增大,MoW涂层电弧烧蚀面积增大明显,呈现出两种烧蚀形貌;孔隙率越大、表面粗糙度越小,涂层耐电弧烧蚀性能越差。MoW喷涂层抗电弧烧蚀性能优于纯Mo喷涂层。 相似文献
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In this study, the effect of arc current on the corrosion behaviour of NiTi coating on stainless steel has been investigated. NiTi powder mixture was alloyed on surface austenitic AISI304 by using plasma transferred arc (PTA) method. Surface alloying process is turned out using 80, 90, 100 A current densities and Ar atmosphere which is plasma and protective. The corrosion resistance of the coatings was analyzed by measuring the potentiodynamic polarization scanning (PDS) technique. Results indicate that corrosion resistances of the coatings decrease with increasing the arc current. In addition, the localized corrosion on the surface of produced coating at 100A is more activated than other coatings and the most passive coating in view of corrosion was obtained at produced coating at 80A. 相似文献
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等离子喷涂AlSi-ployester封严涂层工艺优化研究 总被引:1,自引:0,他引:1
采用AlSi-ployester粉末和PARXAIR-3710等离子喷涂系统制备封严涂层.为使AlSi-ployester等离子喷涂涂层获得优良的涂层性能,选择涂层结合强度为判据,通过正交试验对AlSi-ployester等离子喷涂工艺进行了优化.利用扫描电镜,Axio lmager.A lm金相图像分析系统等手段对涂层形貌和孔隙率进行分析,同时对涂层的硬度、抗热震性能进行了测试.确定优化后的工艺参数为:电弧电流790A.主气流量62.7 L/min,辅气流量5 L/min,喷涂距离100mm.结果表明,电弧电流、主气流量、辅气流量、喷涂距离对AlSi-ployester涂层结合强度具有不同的影响,在优化的喷涂工艺参数条件下,AlSi-ployester涂层结合强度可达6.9MPa,具有较好的硬度和热震性能,可为今后等离子喷涂系统工艺参数的选定提供参考. 相似文献
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分析了机器人等离子熔射过程的神经网络模型的实现方法,基于多层人工神经网络(antificial neural network,ANN)建立了等离子熔射过程的智能化模型.基于该模型,系统研究了等离子弧电流、熔射距离、机器人扫描间距和速度对主要涂层性能参数-残余应力和孔隙率的影响规律,并通过试验数据库的学习对涂层性能参数进行预测.结果表明,模型预测结果与试验结果有着很好的吻合,解决了工艺试验结果中仅有离散数据且难以全面反映等离子熔射工艺参数一涂层性能之间复杂非线性关系的难题.Abstract: The implementation of multi-layer artificial neural networks (ANNs) in robotic plasma spraying was discussed and an intelligent process model was constructed to fully describe the relationships between process parameters and coating properties. Influences of plasma arc current, spray distance, robot scanning space and scanning velocity on coating properties, i.e. residual stress and porosity, were systematically studied based on the present model. Prediction can be effectively carried out after the learning of the experimental database. Theoretical analysis shows the prediction results agree well with the experiments. It is favorable to fully investigate the complex and nonlinear relationships between processing parameters and coating properties as well as to overcome the limited information indicated by the discrete variable in the processing results. 相似文献
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为实现在大口径环状工件内壁沉积金刚石涂层,研制一种能够产生旋转电弧的分体式等离子炬。利用活动阳极形成的伞状电弧帽,改变平行于轴且向下吹的工作气体旋转电离的方向,使其垂直吹向环状工件内壁。测试不同阳极直径下电弧的工作参数,并用相机拍摄相应的电弧形貌。进行金刚石涂层沉积试验,在内径为180?mm的硬质合金拉拔模具和内径为100?mm的石墨内表面沉积出高质量的金刚石涂层。利用拉曼光谱仪和扫描电镜对涂层的成分、表面形貌等进行测试分析。已沉积金刚石涂层的硬质合金模具成功应用于超高压电缆铝护套的拉拔设备中。 相似文献
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作为一种应用十分广泛的金属材料表面后处理工艺,氩弧重熔技术具有均匀金属材料的表层组织、减缓焊接接头的残余应力、改善金属基体与强化层之间的界面结合状态等优点,在一定程度上可以提高金属及表面强化层的性能.综述了氩弧重熔工艺的原理、特点及工艺参数(重熔电流、移动速度、氩气流量和电弧长度)对重熔效果的影响,着重介绍了氩弧重熔技术在金属表面(铸铁、钢和合金)及其表面强化层(涂层、热浸镀层、渗层和堆焊层)后处理过程中的应用进展.最后探讨了金属及表面强化层氩弧重熔工艺的发展方向:1)强化内在机理研究及界面反应状态研究;2)完善快速凝固理论和界面结构研究;3)提升强化层的结构设计与氩弧重熔工艺条件的契合度;4)加强相关的数值模拟研究. 相似文献
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CUI Cai-e MIAO Qiang PAN Jun-de ZHANG Ping-ze ZHANG Gao-hui Research Institute of Surface Engineering Taiyuan University of Technology Taiyuan China No. Research Institute of China Electronics Technology Group Corporation Taiyuan China 《材料热处理学报》2004,25(5)
MAGNESIUM is the8th most abundant element on theearth.Because of that it has some advantageousproperties such as high ratio of strength/weight with adensity that is only2/3that of aluminum and1/4that ofiron,high ratio of rigidity/mass,special characteristicsof electromagnetic shield and shock absorption,excellent cutting and polishing performances,magnesium alloys have been used widely by widely inmany manufacturing industries including aerospace,automobile,electronics and so on.But there i… 相似文献