Turbine wicket gate double-refining casting technique

Abstract

The invention provides a hydraulic turbine guiding blade double refining casting process, which adopts an AOD or VOD refining method to prepare a raw material consumable electrode, and the weight percentages of chemical compositions of the prepared raw material consumable electrode are : less than or equal to 0.05 percent of C, less than or equal to 0.6 percent of Si, less than or equal to 0.58 percent of Mn, less than or equal to 0.03 percent of P, less than or equal to 0.03 percent of S, 11.5 to13.5 percent of Cr, 3.5 to 5.0 percent of Ni, 0.4 to 1.0 percent of Mo, less than or equal to 0.5 percent of Cu, less than or equal to 0.008 percent of N, less than or equal to 0.00035 percent of H and the balance Fe. Then a prepared consumable electrode is made into a hydraulic turbine stainless guiding blade component by electroslag smelting casting method; and the double refining casting process can refine and purify steel liquid completely and effectively so as to remove the gas and non-metallic inclusions in steel greatly. The crystal structure of the casting is uniform and compact, and has low sulfur and phosphorus content, less non-metallic inclusions, higher toughness, anti-fatigue performance and good welding performance.

Description

technical field [0001] The invention relates to a double-refining casting method for a water turbine guide vane, in particular to a manufacturing process for a high-performance water turbine movable guide vane. Background technique [0002] With the development of water turbines towards high efficiency and large scale, some large and medium-sized hydropower stations in my country have been developed and constructed one after another, and the quality requirements for the movable guide vanes, which are important parts of water turbines, are getting higher and higher. At the same time, due to the high sediment content of rivers in our country, the quality and performance requirements for guide vanes of large-scale unit flow components are higher. In addition to having high mechanical properties, it also needs to have anti-fatigue, anti-cavitation performance and certain corrosion resistance. The low-carbon martensitic stainless steel material with higher strength and toughness...

AI Technical Summary

Problems solved by technology

Although high-quality molten steel is provided for casting production through external refining technology (AOD or VOD), but "three-point smelting, seven-point casting", sand castings inevitably produce casting defects such as porosity, shrinkage cavities, and inclusions, which make the internal quality of the product Unstable, difficult to meet the requirements of high-performance indicators, directly affecting the operating life and economic benefits of the turbine

However, welding parts are prone to welding defects, and the process tooling involved is complicated and the cost is high

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