高压钠灯用铌杯冲压工艺的研究

【作者】 谭望；

【导师】 汪明朴； 谢康德；

【作者基本信息】 中南大学 ， 材料科学与工程， 2003， 硕士

【摘要】 冲压是一种冷变形加工方法，是对金属进行塑性加工的主要方法之一。它借助于常规或专用的冲压设备的动力，使板料在模具里直接变形，从而获得一定形状，尺寸和性能的产品零件的生产技术。与塑性加工的其它方法相比，使用模具冲压加工有其独特的优点，特别是使用级进模加工。首先，其生产效率高，一般冲压设备的行程次数都比较高，而且每一次冲压行程就得到一个产品零件。其次，冲压产品的质量好，冲压产品的形状，精度和性能的稳定性由模具的精度得以有效的控制，且冷变形硬化效应提高了产品的强度。随着机械加工精度的提高，级进模加工在国民经济的各个领域的应用日益广泛。 传统的高压钠灯用铌合金封帽采用铌锆合金管加工而成。铌锆合金管加工工艺周期长，成材率低，质量难以保证。并且铌锆合金管的边角废料多，回收处理难度大。另一方面，通过夹扁铌锆合金管焊接加工铌合金封帽时，气密性能难以保证，易造成陶瓷灯管漏气而使成品率降低。 本文在市场需求的前提下，针对铌锆合金管焊接加工铌合金封帽中存在的一些问题，从改善铌合金封帽的气密性能，提高高压钠灯的成品率的角度出发，结合铌杯产品的要求，研究和开发了高压钠灯用铌杯的级进模冲压技术，对其主要工艺模具进行了分析与研究，阐明了其工艺原理。并针对铌锆合金的拉深变形特征，分析了铌锆合金在拉深过程中组织的变化，以及拉深变形后的应力分布和织构的变化，并作了相关的理论计算，并据此设计了铌杯冲压的级进模的结构。通过上述研究，确立了完整的拉深工艺，并生产出了合格的高压钠灯用铌杯产品。 针对用户对所需的铌杯产品的要求，对生产铌杯用铌锆合金板的塑性变形特征进行了分析和试验，确立了基本的冲压工艺路线。针对铌杯产品的壁薄，高径比大，对冲压工艺的精度要求高，冲压成型难度大等特点。对铌锆合金的级进模冲压过程进行了力学分析，结合级进模冲压变形的要求，构建了铌杯的拉深变形路线。通过对铌杯的级进模冲压的工艺计算，结合试验过程中的调整，进行了铌杯拉深的排样计算，通过拉深次数、拉深系数、各道 中南大学硕士学位论文次拉深的尺寸以及其他冲压工艺的研究，确立了银杯的级进模冲压工艺。 为了满足妮杯的拉深变形的要求，对级进模的模具工作过程进行了分析，以及凸、凹模的选择和导向方式和定位方式进行了研究，并对拉深凸模与凹模的结构形式，圆角半径及其工作间隙进行了分析，确立了模具的各主要工作尺寸。同时，对落料凸、凹模，以及切口凸、凹模和其他相关冲压工艺模具进行了分析，确保了拉深工艺的正常进行。 根据锯杯不同部位的拉深变形的特点，研究了拉深变形量对妮销合金的组织的影响。扫描电镜和金相组织分析表明，锯杯的不同部位，由于变形程度的不同，变形后的组织分别由等轴晶和纤维组织组成。随着拉深变形量的增大，组织纤维化逐步加剧。通过锯杯的X射线衍射分析，对拉深变形过程中的锐杯的径向压缩应力和残余应力进行了分析和计算，结果表明，随着变形量的增大，径向压缩应力和残余应力随着增大，晶格畸变也随之增大。织构分析表明，拉深前银铝合金板表现为 （ 00）和＊）织构，拉深后 （）织构明显减弱，但仍保持较强的取向，在拉深过程中还出现了新的（321）织构。 上述研究在高压钠灯用妮杯的生产方面已得到了应用，提高了产品质量和合格率，降低了生产成本，并大大提高了生产效率。更多还原

【Abstract】 Die stamping is a method of cold transformation processing, and it is one of main method of metals proceed plastic working.Compare with the other method of plastic working, using the die in the stamped processing have its special advantage and especially using the progressive die process.The first, the efficiency of manufacturing is very high. Generally the number of strokes of stamped equipments is large, and there is a product or parts in every stroke.The next, the quality of the stamped product is good, and the stamped product’s stability of shape, accuracy and performancce have been controled by the accuracy of dies validly, and the hardening effect of cold-forming increase the product’s strength.Along with the accuracy of the machining advancing, the application of the progressive die to process in the each realm of the national economy is increasingly extensive.Traditionally the sealed hat of niobium alloy using in the high pressure natrium lamp adopt the tube of niobium-zirconium alloy to process.But the cycle of technology is very long as the tube of niobium-zirconium alloy has been prosessed , the rate of finished products is low and the quanlity is difficult to guarantee.And it is difficult to reclaim while the tube of niobium-zirconium alloy make a lot of the waste of leftover bits and pieces. On the other hand, while we clip the tube of niobium-zirconium alloy to weld to the niobium sealed hat, the gas tightness is difficult to guarantee, so it easily result in the ceramic strip lamp to leak air and make the finished product rate lower.This paper aim at the problem exsiting in the process that the tube of niobium-zirconium alloy weld to the niobium sealed hat under the premise of market’need, in order to improve the niobium sealed hat’s performance of gas tightness and increase the finished product rate of the high pressure natrium lamp, research ang develop the stamped technique of progressive die of niobium-cup using in the high pressure natrium lamp,analyse and research the main craft die and explain its technological principle. And combine to the draw-transformed characteristicaim of the niobium-zirconium alloy , analyze the change of the niobium-zirconium alloy’s organization during the course of draw-transform, and the stree’s distribute after draw-transformed andthe alteration of texture, and make the related theories calculation. And on these grounds,I designed the progressive die’s construction of the stamped niobium-cup.Through the above research, establish the complete technology of draw, and have produced the qualified niobium-cup product use in the high pressure natrium lamp .According to the customer’s request for the niobium-cup, analyse and put to test niobium-zirconium alloy sheet’s the characteristic of plastic deformation for niobium-cup’s production, establish the basic stamped craft route.Due to the feature of the product of niobium-cup’s wall is very thin and the ratio of alititude to diameter is large, so the request for accurate stamped craft is very strict,the punch forming is difficult,the mechanical analysis has been made in the process of the stamp of progressive-die for niobium-zirconium alloy,combine to the request of punch deforming of progressive-die I set up the route of draw deforming for niobium-cup.Through technological calculation of the stamp of progressive-die for niobium-cup, combine the trial adjustment in the process, proceeds the calculation of stock-layout for niobium-cup’s draw, through research the number and the coefficient of draw, each time the size of draw and other stamped technology, establish niobium-cup’s stamped technology of progressive-die.In order to meet the request of niobium-cup’s draw deforming, analyse the work processof dies in the progressive-die. Base on the research of the selection between the male die and the female die and the system of guide and the system of allocation,and the analysis of radius of rounded corner and its working clearance, establish each main portion’s work size of the dieAt the same time, the m更多还原