The method offers the advantage that very small samples removed from noncritical locations in the rotor would be sufficient to get the desired data Based on these correlations, a method for estimating K IC with greater accuracy, based on a knowledge of the steel chemistry alone, is proposed. In this work, FATT and K IC data reported for a number of retired CrMoV rotors were gathered and analyzed and correlations specific to CrMoV rotors were developed. The excess temperature vs the K IC correlation that is used to derive the K IC values from the FATT data is based on a variety of low alloy steels and is therefore characterized by a large scatter band, thus leading to considerable uncertainty in the estimated K IC. To determine the FATT of the material, large pieces of material have to be removed, machined into charpy specimens and tested this procedure is often time consuming and expensive and sometimes not feasible. Some problems arise in implementing both of these steps. Current procedures for estimating the K IC involve two steps as a first step, the fracture appearance transition temperature (FATT) at the critical location is determined the FATT value is then used to estimate the K IC, based on published correlations between the excess temperature (T-FATT) and K IC.
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The resulting crack growth equation can be used during integrity assessments for plant components containing cracks which are subject to thermal fatigueĪ method for nondestructive estimation of the fracture toughness of CrMoV rotor steelsĪssessment of the remaining life of steam turbine rotors in the presence of bore defects requires a knowledge of the fracture toughness (K IC ) of the rotors. This observation is compared with the behaviour of other steels and explained by quantitative metallography. Cyclic growth rates measured in the creep-fatigue tests were enhanced compared with pure fatigue rates. Measured growth rates were partitioned into cyclic and hold period contributions and these characterized by the relevant fracture mechanics parameters K and C. Maguire, J.Ĭrack growth rates under simultaneous creep-fatigue conditions have been quantified for a 1 CrMoV rotor steel. The creep-fatigue crack growth behaviour of a 1 CrMoV rotor steel After repair, the rotor was put back into service. The developing of specific in-situ welding repair process of the damaged 20.65 MW gas turbine rotor is described.
On the base of the rotors different failure causes and their mode of occurring, an evaluation of the weldability of the Cr-Mo-V steels and the classification of the common turbine rotors repair possibilities is presented. International Nuclear Information System (INIS)Īn analysis of typical steam turbine and gas turbine rotor failures is carried out. Welding repair of the steam and gas turbines rotors made of Cr-Mo-V steel Despues del proceso de reparacion, el rotor fue puesto nuevamente en servicio. Con base en los danos detectados en el rotor de una turbina de gas de 20.65 MW, se presenta el desarrollo de la tecnologia de reparacion por soldadura llevada a cabo en sitio.
Se lleva a cabo un analisis de la soldabilidad de los aceros al Cr-Mo-V y se presenta una clasificacion de los posibles tipos de reparaciones de los rotores de turbinas, partiendo de las causas y modos de presentacion de las fallas/deterioro del material de los rotores durante la operacion de la turbina. En este articulo se presenta un analisis de los danos tipicos en rotores de turbinas de vapor y de gas fabricados con aceros de baja aleacion al Cr-Mo-V. After the repair process, the rotor was put again in operation. With base on the damages detected in the rotor of a gas turbine of 20.65 MW, the development of the repairing technology carried out by weld in site is presented. An analysis of the weldability of the Cr-Mo-V steel is carried out and a classification of the possible types of repairs of the turbine rotors is presented, starting off from the causes and ways of presentation of the faults/deterioration of the rotor materials during the operation of the turbine. In this article an analysis is presented of the typical damages in steam and gas turbine rotors made of Cr-Mo-V low alloy steels. [Comision Federal de Electricidad (Mexico) Mazur C, Zdzislaw Hernandez R, Alejando [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico) Orozco S, Julian Banuelos P, Jose E. Repair by weld of steam and gas turbine rotors made of Cr-Mo-V steel Reparacion por soldadura de rotores de turbinas de vapor y de gas fabricados con aceros al Cr-Mo-VĮnergy Technology Data Exchange (ETDEWEB)
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