This utility model relates to the field of
steam turbine technology, specifically to a fir-tree type blade root structure, blades, and a
steam turbine. The fir-tree type blade root structure provided by this utility model includes a blade root with a first side and a second side arranged opposite to each other. The first side is located on the back arc side of the blade root, and the second side is located on the inner arc side of the blade root. The second side has a protruding structure, and the first side has grooves corresponding to the protruding structures. The blade roots of each pair of adjacent blades
interlock through the protruding and groove structures. The
interlocking of the blade roots between each pair of blades, through the protruding and groove structures, allows the blade roots to mutually restrain each other during operation, limiting the circumferential sway range of the blades, thereby solving the problem of blade swaying due to low
centrifugal force when the blades are lightweight or operate at low speeds.