Steam turbine

Abstract

The invention provides a steam turbine which comprises a high pressure inner cylinder and a high pressure outer cylinder, wherein the high pressure inner cylinder is made of martensite material; and a0.1-1mm of inner liner is arranged on the surface of the inner wall of the high pressure inner cylinder and is made of nickel base alloy. According to the stem turbine, through arranging the 0.1-1mmof inner liner made of nickel base alloy on the surface of the inner wall of the high pressure inner cylinder, the mechanical strength and the steam oxidation resisting capacity of the high pressure inner cylinder at high temperature are improved, and the using temperature of the steam turbine is raised.

Description

technical field [0001] The invention relates to the field of power equipment, in particular to a steam turbine. Background technique [0002] Existing large-scale steam turbines generally adopt a double-layer cylinder structure, including a high-pressure inner cylinder and a high-pressure outer cylinder. The inner wall of the inner cylinder directly contacts the high-temperature steam, and the outer wall of the outer cylinder contacts the environment. There is an interlayer between the inner cylinder and the outer cylinder. The steam with a slightly lower temperature and pressure is introduced, so that the inner cylinder only needs to withstand the differential pressure between the working steam and the interlayer steam, the wall thickness can be significantly reduced, and the temperature difference between the inner wall temperature and the outer wall (interlayer) temperature of the inner cylinder is reduced. Small, can also avoid a large internal stress. The outer cylinde...

AI Technical Summary

Problems solved by technology

The current high-pressure inner cylinder adopts CB2 steel and 9Cr–3W–3Co heat-resistant steel. The allowable temperature does not exceed 625°C. After the allowable temperature is exceeded, the material of the high-pressure inner cylinder cannot meet the anti-oxidation requirements of the steam side.