Assembling method of stator blade ring segment, stator blade ring segment, coupling member, welding method

A coupling member for coupling a plurality of segment pieces to form a stator blade ring segment, a plurality of which are assembled to form a stator blade ring including a plurality of stator blades provided between an annular inner shroud and outer shroud, the plurality of segment pieces each including one of said stator blades provided between an inner shroud portion formed by circumferentially splitting said inner shroud and an outer shroud portion formed by circumferentially splitting said outer shroud,

• said coupling member has a band shape and is formed with protrusions on opposite side surfaces in a width direction so as to have a maximum width at an intermediate portion in a thickness direction, and
• when said coupling member is placed in a groove formed in at least either of said inner shroud portion and said outer shroud portion of said segment piece, a space is formed on the side of the bottom of said groove with respect to said protrusion and a welding groove having a substantially V-shaped section is formed on the side opposite to said bottom with respect to said protrusion between the side wall portion of said groove and said side surface of said coupling member.

A method of welding a first member formed with a groove or a recess to a second member placed in said groove or said recess at least at a part of an outer peripheral portion of said second member,

• wherein said groove or said recess has a side wall portion inclined so that an opening width of the groove or the recess gradually decreases toward a bottom, and said second member is formed with a protrusion on a side surface of the outer peripheral portion so as to have a maximum width at an intermediate portion in a thickness direction,
• when said second member is placed in said groove or said recess, a space is formed on the side of said bottom with respect to said protrusion and a welding groove having a substantially V-shaped section is formed on the side opposite to said bottom with respect to said protrusion between said side wall portion and the outer peripheral portion of said second member, and
• said welding groove is welded at least at a part of the outer peripheral portion of said second member to weld said first member to said second member.