Research Of Electroslag Casting Large Guide Vane Guide Vane

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.