A method for treating the deformation of the joint surface of the steam turbine cylinder

Abstract

The invention relates to a steam turbine cylinder joint surface deformation processing method. The method comprises following steps:1) sending a low-pressure inner upper cylinder to a steam turbine factory for machining and rubbing down; 2) polishing the lower cylinder joint surface of a low-pressure inner lower cylinder based on the machined inner upper half cylinder; 3) cleaning burrs on the machined cylinder surface and traces remained by the machining; 4) hoisting all carrier rings and separator plates in the lower cylinder; 5) cleaning the surface of the lower cylinder; 6) making analysis according to measured results and traces pressed on the lower cylinder joint surface; 7) employing a mechanical polishing tool to polish the lower cylinder joint surface from the thickest position to be polished and gradually and radially enlarging the polishing area, wherein the joint surface is repeatedly polished in the vertical and horizontal directions by a long flat ruler during each polishing process; 8) finely polishing the joint surface when a set scraping value of a depth mark is remained; and 9) repeating the step 8) until the joint surface gap value meets requirements. Compared with the prior art, the cylinder deformation can be completely eliminated through the method, and the maintenance is convenient and reliable.

Description

technical field [0001] The invention relates to a steam turbine maintenance technology, in particular to a method for treating the deformation of the joint surface of a steam turbine cylinder. Background technique [0002] After a certain operation period of the steam turbine, the cylinder block will be more or less deformed to a certain extent. The most intuitive manifestation is that the face of the cylinder will cause a large gap, and steam leakage on the cylinder surface and channeling between stages will occur during operation. The steam turbine operates safely and stably and reduces the thermal efficiency of the unit; at the same time, in the maintenance process, considerable manpower and material resources must be invested in order to eliminate the deformation, and it is technically difficult to guarantee the quality. [0003] There are many factors that cause the deformation of the cylinder, which are related to the design of the cylinder body; the quality of the mat...

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Problems solved by technology

[0002] After a certain operation period of the steam turbine, the cylinder block will be more or less deformed to a certain extent. The most intuitive manifestation is that the face of the cylinder will cause a large gap, and steam leakage on the cylinder surface and channeling between stages will occur during operation. The steam turbine operates safely and stably and reduces the thermal efficiency of the unit; at the same time, in the maintenance process, considerable manpower and material resources must be invested in order to eliminate the deformation, and it is technically difficult to guarantee the quality

[0003] There are many factors that cause the deformation of the cylinder, which are related to the design of the cylinder body; the quality of the material; the process of processing and handling; the operation and maintenance, etc. The permanent deformation of the cylinder due to the above reasons makes it difficult to eliminate the cylinder gap

[0004] After the cylinder is deformed, in order to eliminate the mid-section gap, the cylinder bolts are forced to be over-tightened, the bolt stress increases sharply, the service life of the bolts is shortened, and even fracture occurs; after the cylinder surface bolts are tightened, the deformation is eliminated and at the same time , forcing the steam and shaft seal gap (mainly refers to the radial direction) to be inconsistent with the free state, which increases the difficulty and work intensity for the judgment and adjustment of the steam and shaft seal gap. Accurate data when the measured value is cold every time

In addition, if the bearing seat and the cylinder are of an integral structure, it will also affect the measurement and adjustment of the shafting center between the half cylinder and the real cylinder.

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