Method of manufacturing stay ring for water turbine and pump turbine

A method of manufacturing a stay ring for use in a water turbine and a pump turbine, the stay ring having an upper annular disc and a lower annular disc and a plurality of circumferentially spaced stay vanes each extending between the upper and the lower annular discs, comprising the steps of:

• providing upper and lower annular discs;
• forming openings in at least the upper annular disc of said upper and lower annular discs at each of the uniformly peripherally spaced locations where said stay vanes are to be positioned;
• locating said upper and lower annular discs in a spaced parallel relation to each other with a fixed distance therebetween;
• placing a plurality of molds, each having therein a space of a shape conforming to the shape of said stay vane, at fixed positions between said upper and lower annular discs, such that said spaces in the molds are put into communication with corresponding ones of said openings in said upper annular disc;
• thereafter effecting an electroslag welding in each of said spaces in the molds by passing a consumable electrode through associated openings in said upper annular disc and into corresponding mold spaces to first bond electroslag molten metal material to said lower annular disc, to second fill said space in the mold with electroslag molten metal material, and third to bond the electroslag molten metal material to said upper annular disc and at least fill a portion of a space defined by the associated opening in said upper annular disc with electroslag molten metal;
• thereafter cooling and solidifying said electroslag deposited molten metal filling said spaces in the molds to form said stay vanes and, at the same time, to permanently and rigidly connect said upper and lower annular discs through the thus formed stay vanes;
• and
• thereafter removing said molds from said stay vanes respectively by disassembling each mold into a plurality of pieces.