【作者】 张力；

【导师】 毛建中； 韩志华；

【作者基本信息】 湖南大学 ， 机械工程（专业学位）， 2017， 硕士

【摘要】 管座制造技术是“压水堆燃料元件设计制造技术项目”技术国产化、自主化必须攻克的关键技术之一。现有压水堆燃料元件管座工艺采用机械加工与焊接的工艺方法,加工成本高且效率较低。本项目管座采用精密铸造(熔模铸造)再加工的工艺,精密铸造可以做到管座的流水孔道以及裙边内部结构直接铸造成型,应用机械加工对要求较高的外形以及所有孔系进行加工,使在管座加工中减少材料去除量、减少成型刀具种类、缩短加工时间,整体上有效的降低加工成本。具体开展了以下几方面的研究:(1)开展了压水堆核燃料组件管座精密铸造制蜡、制壳工艺技术研究,确定主要工艺流程及相关工序主要工艺参数。蜡模压制方面通过调整蜡液温度、射蜡压力、射蜡时间及保压时间等参数解决精密铸造蜡模易出现的表面质量问题,得到合格精密尺寸的蜡模产品;制壳工艺方面主要针对浆料配比、机器人动作、淋砂机调整、干燥温度及干燥时间等开展工艺探索与研究,确定了重要工艺参数。(2)开展了管座铸造后的检测研究,管座铸造后需要按照设计要求进行的X光、渗透、尺寸、化学成分、晶粒度、抗腐蚀性能、力学性能检测项目,通过试验建立了相应的检测方法。(3)开展了铸造后管座的加工工艺研究,采用数控加工中心设备对管座的外形、四周倒角、孔系、中心孔、定位孔等要求较高的尺寸进行加工,根据孔系中的特殊腰型槽结构设计制作了专用刀具实现孔内侧槽的加工,并达到设计要求精度;对中心孔的台阶孔及内部倒角,采用了设计制作专用台阶钻一体成型的加工方案,保证孔的同轴度,并且能够很有效的提高加工效率。通过本项目研究制出合格的上下管座产品,掌握了管座的精密铸造、加工、检测等技术,形成相关制造、检测工艺,具备管座精密铸造生产能力。将进一步推进管座精密铸造的产业化发展,为全面实现压水堆核电核燃料组件管座精密铸造的产业化提供理论支持和实现基础。更多还原

【Abstract】 Nozzles manufacturing is one of the key technologies of localization and autonomy which needs to overcome for realize PWR fuel assembly design and manufacturing.The process of machining and welding is used in existing PWR fuel assembly nozzles,high processing cost and low efficiency.This project adopts the precision casting tube(casting)process processing,the internal structure of the water hole and the skirt of the nozzle can be directly cast,the appearance and all holes with high requirements are machined,the amount of material removal,the cutter type,the conversion cost are reduced effectively and the producing time is shorten,Specific research is carried out in the following aspects:(1)The research of producing wax,shell making of PWR was carried out,the main process and parameters of related process was determined.the surface quality problems of wax mould are solved by adjusting the temperature of liquid wax,the pressure and the time of wax injection,and the pressure holding time,conformed wax products were produced;the research of the slurry ratio,robot motion,sand sprinkling machine,drying temperature and drying time of shell making were carried out,important process parameters were determined.(2)the inspection of nozzle after casting were carried out.The corresponding inspection method of the X ray,permeability,dimension,chemical composition,grain size,corrosion resistance,mechanical performance test which meet the design requirements were established by experimenting.(3)the process research of nozzle after casting is carried out,the nozzle shape,chamfer,holes,center hole,positioning holes and other high requirement dimensions is machined by the CNC machining center equipment,special tool is designed for manufacturing the inner groove of holes according to the special groove back structure to meet the design requirements and accuracy;the processing scheme design for step hole and internal chamfer of center hole of the step drill integrated was adopt,the coaxiality of holes are ensured,and the processing efficiency can be effectively improved.After this project is researched,conformed top and bottom nozzles were manufactured,the precision casting,manufacturing,inspection of nozzles weremastered,production capacity of procession casting is possessed.The industrial of the nozzle of precision casting will be further promoted,the theoretical support and basis of precision casting industry will be provided for the full realization of fuel assembly nozzle for PWR.更多还原