Final blade in low-pressure-stage group of high-flow air cooling steam turbine

The utility model discloses a final blade in a low-pressure-stage group of a high-flow air cooling steam turbine. The blade is a variable-cross-section twisted blade used for the high-flow air cooling steam turbine with steam discharge area of 3.6m , and comprises a blade body, a blade root and a shrouding band and a shrouding wire boss for enabling the blade to form a whole circle of self-locked state, wherein the relative blade height Ld of the blade body is monotonously increased to 100% from 0%; the ratio T/b of the pitch from the blade root section to the blade top section to chord length has the change rule that T/b is not less than 0.4 and not more than 1.0; the ratio T/B of the pitch from the blade root section to the blade top section to the axial width of the blade section has the change rule that T/B is not less than 0.4 and not more than 3.0; and the ratio T/Dmax of the pitch from the blade root section to the blade top section to the maximum thickness of the blade section has the change rule that T/Dmax is not less than 2.5 and not more than 22.5. The blade has operation performance in variable working condition and strength vibration performance, reasonable structure, convenience for assembly and wide market application prospects.