scholarly journals STRUCTURE AND MECHANICAL PROPERTIES OF 21HMF STEEL STEAM TURBINE ROTOR MATERIALS AFTER LONG-TERM OPERATION FOR A TIME SIGNIFICANTLY EXCEEDING THE DESIGN TIME

2021 ◽  
Vol 73 (2) ◽  
pp. 40-55
Author(s):  
Joanna FURMANEK ◽  
Janusz DOBRZAŃSKI
Keyword(s):  
Mechanical Properties ◽  
Steam Turbine ◽  
Functional Properties ◽  
Turbine Rotor ◽  
Working Time ◽  
Term Operation ◽  
Steam Turbine Rotor ◽  
Design Time ◽  
Turbine Rotors

The article presents the results of tests of materials for steam turbine rotors with various degrees of depletion in order to determine the suitability of these components for further operation after significantly exceeding the design working time on the basis of the assessment of the microstructure condition and a set of functional properties.

scholarly journals Investigation of bowing of steam turbine rotor during long term service.

1984 ◽  
Vol 24 (2) ◽  
pp. 107-112 ◽  
Author(s):  
Seishin KIRIHARA ◽  
Masao SHIGA ◽  
Mitsuo KURIYAMA ◽  
Ryoichi SASAKI ◽  
Katsukuni HISANO
Keyword(s):  
Steam Turbine ◽  
Turbine Rotor ◽  
Steam Turbine Rotor

Influence of Creep on Low-Cycle Fatigue Life Assessment of Ultra-Supercritical Steam Turbine Rotor

2014 ◽  
Author(s):  
W. Z. Wang ◽  
J. H. Zhang ◽  
H. F. Liu ◽  
Y. Z. Liu
Keyword(s):  
High Temperature ◽  
Steam Turbine ◽  
Fatigue Damage ◽  
Low Cycle Fatigue ◽  
Turbine Rotor ◽  
High Temperature Creep ◽  
Cycle Fatigue ◽  
Term Operation ◽  
Start Up

Linear damage method is widely used to calculate low-cycle fatigue damage of turbine rotor in the long-term operation without fully considering the interaction between creep and low cycle fatigue. However, with the increase of steam turbine pressure and temperature, the influence of high-temperature creep on the strain distribution of turbine rotor becomes significant. Accordingly, the strain for each start-up or shut-down process is different. In the present study, the stress and strain during 21 iterations of continuous start-up, running and shut-down processes was numerically investigated by using the finite element analysis. The influence of high-temperature creep on low cycle fatigue was analyzed in terms of equivalent strain, Mises stress and low cycle fatigue damage. The results demonstrated that the life consumption of turbine rotor due to low cycle fatigue in the long-term operation of startup, running and shutdown should be determined from the full-time coverage of the load of turbine rotor.

Evaluation of Fatigue Damage by X-Ray Diffraction Technique of Steam Turbine Rotor Steels at Elevated Temperatures

2009 ◽  
Author(s):  
Jaroslav Fiala ◽  
Vaclav Mentl ◽  
Vladislav Kolarik ◽  
Michal Chocholousek
Keyword(s):  
Mechanical Properties ◽  
Steam Turbine ◽  
Fatigue Damage ◽  
Elevated Temperatures ◽  
Turbine Rotor ◽  
Residual Lifetime ◽  
X Ray Diffraction ◽  
Time Service ◽  
X Ray ◽  
Steam Turbine Rotor

In many industrial applications materials are subjected to degradation of mechanical properties as a result of real service conditions. The assessment of the remaining lifetime of components and structures is commonly based on correlated procedures including numerous destructive, non-destructive and mathematical techniques that should guarantee reasonable precise assessment of the current damage extent of materials in question and the remnant lifetime assessment. The assessment of the remaining lifetime by X-ray diffraction technique is based on the fact that mechanical properties of the most materials depend strongly on crystallite size and orientation of ingredients, which are the crucial parameters for the determination of the ageing state and the prediction of residual lifetime of the components. X-ray diffraction technique proved to be useful as a tool for the assessment of material degradation extent after a long-time service. Framework 5 project “XPECTION” [1] was dealing with this task with respect to high temperature creep degradation of boiler tube steels. In this presentation, the X-ray diffraction technique was applied to reveal subtle details of the microstructural changes induced by fatigue. Several steam turbine rotor steels were fatigue tested at elevated temperatures up to 600°C at strain control regime. After the tests, the X-ray diffraction method was used to correlate the extent of fatigue damage with the X-Ray diffraction patterns to be able to assume the life-time exhaustion caused by fatigue loading in service.

Fault Analysis and Optimal Balancing of Bowing of Steam Turbine Rotor Under Long-Term Service

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Jingming Chen ◽  
Dongxiang Jiang ◽  
Chao Liu
Keyword(s):  
Steam Turbine ◽  
Traditional Approach ◽  
Turbine Rotor ◽  
Fault Analysis ◽  
Time Service ◽  
Steam Turbine Rotor ◽  
Start Up ◽  
Long Time

In recent years, bowing of steam turbine rotor under long time service occurs in several high-parameter units. Collected data show that the bending of the haywire rotor is increasing continuously, which results in excessive vibration in operation and even causes over-limit vibration during start-up. In order to suppress the vibration, balancing is utilized in field with the traditional approach that the balancing mass is placed in the section of the rotor close to the bearing. However, the balancing with the traditional approach could only reduce the vibration temporarily. In the long time scale, the bowing is still propagating or even gets worse after the balancing. To determine the cause of bowing and form optimal balancing approach, analysis is carried out in this work including: (i) fault cause and its treatment of bowing of steam turbine rotor under long time service is studied with elastic–plastic mechanics and creep mechanism taken in account; (ii) a case study was carried out, where the bowing process was simulated and validated with the field monitoring data; (iii) the phenomenon of the traditional balancing method was illustrated with rotordynamics analysis, where the influence of whirling is included. Based on the analysis, the cause of bowing is determined as uneven creep effect. And the balancing method would influence the whirling mode, which would worsen bowing in the traditional balancing method. Based on this conclusion, an optimized balancing method was developed to reduce the vibration and prevent bowing propagation simultaneously.

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