Electroslag smelting casting method of fixed blades of water turbine

Abstract

The invention relates to an electroslag smelting casting method of fixed blades of a water turbine. Consumable electrodes are prepared by adopting a voltaic arc furnace refining method and the fixed blades are prepared by adopting an electroslag smelting casting process through a mould. The chemical components of the consumable electrodes are controlled as follows: C is 0.14-0.19 percent, Si is less than or equal to 0.6 percent, Mn is 1.5-1.9 percent, P is less than or equal to 0.035 percent, S is less than or equal to 0.035 percent, V is 0.02-0.15 percent, Nb is 0.015-0.06 percent, Ti is 0.15-0.25 percent, Al is more than or equal to 0.015 percent, O is less than or equal to 0.0040 percent, N is less than or equal to 0.0080 percent, H is less than or equal to 0.00035 percent, and the balance is Fe. The electroslag smelting casting system and the electroslag guide are controlled as follows: CaF2 is 60-80 percent, Al2O3 is 40-20 percent, or less MgO and CaO (the total is less than or equal to 20 percent); and the electroslag amount is usually 1.5-5 percent of the weight of a casting. The invention has less amount of oxide and sulfide, small size, even distribution, clean casting base body, high cooling speed, large crystallization temperature gradient at the front of solid and fluid, compact casting texture, high size precision and little distortion, and can greatly improve the product property of the refined casting.

Description

technical field [0001] The invention relates to an electroslag casting process for a fixed guide vane for a hydraulic generator, in particular to a manufacturing process for a large-scale, high-performance fixed guide vane for a hydraulic generator. Background technique [0002] With the successive development and construction of some large and medium-sized hydropower stations in my country, water turbines are developing in the direction of high efficiency and large-scale, and the quality requirements for important parts of water turbines are getting higher and higher. At the same time, due to the high sediment content in rivers in our country, the quality and performance requirements for large-scale unit flow components are very high. In addition to high mechanical properties, flow flow components also need to have fatigue resistance and certain corrosion resistance. [0003] At present, the production methods of fixed guide vanes for hydroelectric generators include sand c...

AI Technical Summary

Problems solved by technology

The quality of sand casting castings is closely related to the quality of molten steel. Although high-quality molten steel is provided for casting production through out-of-furnace refining technology (AOD or VOD), casting defects such as looseness, shrinkage cavities, and inclusions inevitably occur in sand castings, making the product The internal quality is unstable, and it is difficult to meet the requirements of high performance indicators, which directly affects the operating life of the turbine

The quality of rolled steel plate is high, but the material utilization rate is low, the process is complicated, and the cost is high

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