【作者】 闫文涛；

【导师】 刘喜海；

【作者基本信息】 东北大学 ， 钢铁冶金， 2008， 硕士

【摘要】 为了提高水轮机机组的整体寿命,采用了电渣熔铸工艺生产机组的主要过流部件—导叶,导叶的材质采用超低碳马氏体不锈钢0Crl3Ni4Mo。由于传统的电渣产品都是形状简单的圆形铸件,而导叶的结构比较复杂,所以在电渣熔铸导叶生产设计过程中,遇到了一系列的问题。由于导叶与传统电渣铸件结构的不同,传统的经验公式不再适用,引入了等效圆和等效面积的概念,使经验公式适用于复杂的产品设计。还引入了换箱概念以解决没有电渣熔铸导叶所需要的足够的公用型腔的问题,我们将导叶结晶器设计为上下结构。将用电渣熔铸方法制造的大花导叶的试块与砂型铸造试块同炉热处理,对上述两试样进行化学成分、非金属夹杂物、机械性能、超声波汽蚀、金相组织等项目对比试验分析,可以看出采用电渣熔铸工艺生产的大花导叶有害元素S含量降低大约为30%以上,钢水纯净,组织致密,成份稳定。导叶内部无缩松、夹杂、气孔、裂纹等铸造缺陷,夹杂物分布均匀、细小,达到GB1056-89 1-2级水平,比以往砂型铸造导叶提高1个等级。在电渣熔铸导叶生产过程中,开发了异型件熔铸的生产工艺和异型结晶器的设计技术,掌握了电极的尺寸确定、以及生产过程中渣制度和电制度的控制技术。对水轮机过流部件进行喷丸处理,测量了喷丸影响层显微硬度、X射线衍射半高宽度和屈服强度等参量的沿层深分布、并计算了相应的晶块尺寸、微观应变和位错密度的等微观结构参量。结果表明,该影响层以显微硬度和屈服强度表征的组织强化效应显著、显微硬度和屈服强度提高是由于晶块细化、微观应变和位错密度增大造成的。喷丸影响层不同部位的显微硬度与条件屈服点之比约为3.37；研究成果生产的大花导叶化学成分、力学性能、无损探伤、夹杂物、高低倍检测等主要技术指标均达到或超过了用户技术协议的要求,大花导叶的生产实践表明,本课题的研究成果可以用于实际生产。更多还原

【Abstract】 In order to improve hydraulic turbine service life, we adopt ESC technology to produce the guide vane which is chief Tran flux part of the equipment. The guide vane is made of 0Cr13Ni4Mo. The traditional electroslag ingot has a simple round shape while vane has a complex profile; we encounter a lot of problems in the production process of the electroslag casting guide vane.The traditional empirical formulas can not be adopted because of the differences in the shape in guide vane and traditional ingots. This project presents the concepts of equivalent circle and equivalent area, so as to the empirical formulas can be used in the complex technological design of products. This project also introduces the concept of displace box for the sake of solving the lack of common cavity die of ESC guide vane and the upper and lower crystallizer is designed.Put the test sample of guide vane made of ESC and the one made of sand casting in the same furnace to heat them. Comparing the test samples in chemical composition, non-metallic inclusions, mechanical properties, ultrasonic wave cavitations erosion, and metallurgical structure and so on, we can know that the ESC guide vane is cleanliness, dense macrostructure and consistent composition. There are not casting flaws such as shrinkage cavities, inclusions, gases and crackle in the guide vane. The inclusion has a homogeneous distribution and small size, which can reach 1-2 level of GB1056-89. it elevates a grade in comparison with the process of sand mould.A low carbon martensite stainless steel 0Cr13Ni4Mo normalized at 1000℃and tempered at 600℃,used in the guide stream assemblies of water turbine,was treated with shot peening.The depth distributions of microhardness,half-width value of X-ray diffraction profiles and yield strength in the shot-peening affected layer were measured.Correspondingly,the depth distributions of microstructure parameters,such as subgrain size,microstrain and dislocation density,in this layer were calculated.The experimental results indicate that the structure strengthening charactered by microhardness and yield strength is prominent.The subgrain size decreases,and the microstain and dislocation density increase in the shot-peening affected layer,which results in the increase of the microhardness and yield strength.The ratios of microhardness to proof stress are all about 3.37 in different depth of the affeceted layer.In the process of producing guide vane, we master the production technology, crystallizer and electrode dimension design, and we know the control technology of slag and electricity.The chemical composition, mechanical properties and nondestructive evaluation of the guide vane in this project reach and even surpass the requests of the protocol. The productive practice in guide vane power station indicates that the research achievements of the project can be used in actual production.更多还原