HIGH AND INTERMEDIATE PRESSURE STEAM TURBINE

摘要

A high and intermediate pressure turbine, comprising: a high and intermediate pressure turbine rotor (10) which includes a first rotor member (30) and second rotor members (20, 40) that are joined to both ends of the first rotor member (30); an external casing (60); and an internal casing (70) disposed inside the external casing (60). The first rotor member (30) is formed of an Ni-based alloy material, and an average linear expansion coefficient thereof in a temperature range from room temperature to 700°C is from 12.4 × 10 -6 /°C to 14.5 ×10 -6 /°C, and the second rotor members are formed of high Cr-steel materials, and an average linear expansion coefficient thereof in a temperature range from room temperature to 700°C is from 11.2 × 10 -6 /°C to 12.4 ×10 -6 /°C. The turbine rotor (10) includes blade rows (12) in a high pressure turbine chamber (61A) and an intermediate pressure turbine chamber (61B). High pressure steam is configured to be supplied to a high pressure turbine chamber (61A) side of a partition wall (60b) in the external casing (60) separating into the high pressure turbine chamber (61A) from the intermediate pressure turbine chamber (61B), intermediate pressure steam is configured to be supplied to an intermediate pressure turbine chamber (61B) side of the partition wall (60b), and the stream is configured to flow into a high pressure turbine portion and an intermediate turbine portion.