Statistical method of estimation of stability of parameters of rotor blades of steam turbines of thermal power plants during manufacturing and testing

The paper is devoted to relevant issue of raising the quality and reliability of rotor blades of steam turbines. This is due to the fact that the number of failures of rotor blades exceeds 60% of all failures of steam turbines, which are in operation. The developed method of control of stability of parameters and reliability of rotor blades during their manufacturing and testing is proposed to introduce in addition to the existing method of quality control of rotor blades of steam turbines. The methods of quality control of rotor blades during the process of their manufacturing and testing according to existing normative documentation are described in detail. The form 1 “List of defects, malfunctions and failures, which have been revealed during manufacturing and testing” and form 2 “Inspection chart of stability of parameters” have been developed in addition to normative documentation. The calculation equations for estimation of stability of parameters of technological processes and reliability level have been presented. A technique for determination of extreme deviation of parameters and regulation boundaries according to preset tolerance has been developed. An example of stability control of natural oscillation frequency has been presented. The presented technique has been implemented at special purpose enterprises. An internal certificate is drawn up for each set of rotor blades at the manufacturing plant with a view to gather statistical information. This certificate is developed by the manufacturer. Information about the material certificate, the results of control, which has been carried out during the process of manufacturing and testing, with indication of deviations from the draft, the technical specifications during the testing, the description of technological process of thermal treatment of stocks etc. are noted down in the internal certificate.

stability, parameters, blades, manufacturing, testing, inspection chart, tolerance, deviations, statistical information

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