Research On Developing Aluminium Mould Of ESC Small Guide Vanes

Shenyang Research Institute of Foundry (SRIF) makes use of ESC to produce follow passage components for hydro turbine. SRIF developed this technology on her own and ESC guide vanes technology has been unique in the world. SRIF has provided more than 1,000 pieces guide vane castings for Harbin Electric Machinery Co., Ltd, Dongfang Electric Machinery Co., Ltd, Tianjin Alstom Electric Machinery Co., Ltd, General Electric Hydro Equipment Asia Co., Ltd etc. Both the manufacturing technology and quality of guide vanes have been up to the advanced level in the world. She has grappled key technology about research on developing mould that made SRIF achieve success on ESC.The mould is main component for electro-slag remelting furnace. Mould is as the melting room where remeltand refine metal. Otherwise the mould is regarded as casting mould where metal was forcible cooled and formed casting.Conventional ESC moulds were made of steel or mixed copper-steel. These conventional ESC moulds had different degree defect. Steel mould cost-efficient but its diathermanous submultiple is little which made casting's moulding was not good. These would make difficulty during clearing and repairing. If the cooling strength of rotative water wasn't met during remelting, steel mould would appear conglutination, distortion , leaking slag ,leaking water phenomena etc. which sesult in casting destroy or safeless. In addition, if steel mould appeared distortion,it would to be difficult to repair. So its life of steel mould is shorter. The submultiple of copper mould is larger. So the surface quality of guide vane is very good. But, the weldability between copper and steel is bad. Each other don't have suitable melting zone. So, it is difficult to make and repair mixed copper-steel mould. Only making use of measure of predigested mould-line when the cross section of guide vane changes biggishly and structure is complex. This measure makes maching allowance augment, using efficiency decrease and cost increase. So the application of mixed copper-steel mould is restricted.SRIF have done some groping tests in order to find one metal that is economical and fit for processing mould since 2003. Finally, SRIF fixed on Aluminium alloy. All performance targets of Aluminium alloy are lay between copper and steel. Its weldability is good and price is lower than that of copper. Otherwise its machining and castability are both good also.