Long-term service induced mechanical properties change of welding metals in a gas turbine rotor

2021 ◽  
pp. 142323
Author(s):  
Shao-Shi Rui ◽  
Qi-Nan Han ◽  
Xue Wang ◽  
Jia-Min Zhao ◽  
Zhipeng Cai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gas Turbine ◽  
Turbine Rotor

scholarly journals Effect of Long Term Exposure on Mechanical Properties and Precipitation Behaviors of Hastelloy X for Gas Turbine Combustor

1993 ◽  
Vol 79 (11) ◽  
pp. 1293-1298
Author(s):  
Yomei YOSHIOKA ◽  
Daizo SAITO ◽  
Kazunari FUJIYAMA ◽  
Nagatoshi OKABE ◽  
Shinichi NAKAMURA
Keyword(s):  
Mechanical Properties ◽  
Gas Turbine ◽  
Gas Turbine Combustor ◽  
Hastelloy X

Crack Initiation Behavior and its Estimation for a Gas Turbine Rotor Based on the EBSD Analysis

2012 ◽  
Author(s):  
Daisuke Kobayashi ◽  
Akihiro Ito ◽  
Masamichi Miyabe ◽  
Yukio Kagiya ◽  
Yomei Yoshioka
Keyword(s):  
Crack Initiation ◽  
Grain Boundary ◽  
Gas Turbine ◽  
Hold Time ◽  
High Stress ◽  
Turbine Rotor ◽  
Electron Back Scatter Diffraction ◽  
Mechanical Fracture ◽  
Turbine Rotors

Gas turbine rotors made of Ni-base superalloys were sometimes found to have cracks at the dovetail of the first and second stage wheel. In order to maintain the reliability of gas turbine rotors over the long term, in addition to the application of countermeasures such as the shot-peening process, it is essential to confirm the characteristics of crack initiation mechanisms and to predict the possibility of new cracking. In this paper, first, the case study of crack initiation concerning a wheel dovetail crack has been carried out. Second, to reveal the characteristics of the crack, comparative evaluation between the actual crack and various mechanical fracture samples were conducted by using a scanning electron microscope (SEM) and the electron back-scatter diffraction (EBSD) method which can analyze crystallographic misorientation. As a result, it was found that even in relatively low temperatures, Inconel® Alloy 706 is subjected to brittle grain boundary oxidation when under constant high stress, i.e. a similar phenomenon to stress accelerated grain boundary oxidation (SAGBO), so called hold-time cracking (HTC).

scholarly journals Effect of Long-term Service on Microstructure and Mechanical Properties of NiCrMoV Steel Welded Joint

2019 ◽  
Vol 269 ◽  
pp. 03012
Author(s):  
Manjie Fan ◽  
Peng Wang ◽  
Qixing Sun
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Welded Joint ◽  
Welding Process ◽  
Turbine Rotor ◽  
Optical Microscope ◽  
Turbine Plant ◽  
Nicrmov Steel ◽  
Service Conditions

The influences of prolonged service on microstructure evolution and mechanical properties of NiCrMoV steel welded joint in an ex-service welded steam turbine rotor were investigated. The welded rotor had been operated for 22 years since 1991. The specimens for the present study were taken from the location where the temperature was as high as 230°C. The optical microscope (OM) showed that even after long-term service, there were no obvious defects such as creep cavities, cracks found in the microstructure of the whole welded joint after such a long term service. The microstructure was uniform and no obvious grain coarsening was observed. However some black strip-shaped zones were found in base metal and heat affected zone (HAZ). The distribution of hardness across the welded joints showed no anomalies. The results of tensile strength and fracture toughness tests demonstrated that the welded joint still exhibited excellent. Mechanical performance after long-term service, indicating that the welding process of Shanghai Turbine Plant was reliable and stable. With the improvement of forging and welding qualities and improved heat treatment furnaces with more accurately controlled temperature, it is reasonable to assume that the current large low-pressure (LP) welded rotors are definitely safe to operate under similar service conditions for designed life.

Long Term Thermal Stability of Several Gas Turbine Alloys

2005 ◽  
Author(s):  
L. M. Pike ◽  
S. K. Srivastava
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Gas Turbine ◽  
Operating Costs ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Haynes 230 ◽  
One Year ◽  
Thermal Stability Of

Ever increasing demands for lower gas turbine operating costs have led to the need for longer lasting components. This in turn, requires the availability of alloys which are reliable to such long lifetimes. In the mill produced condition, most alloys have desirable microstructures and mechanical properties. However, after exposure to the harsh temperatures found in gas turbine engines, the microstructures of most alloys will begin to change. The effects on the mechanical properties of such microstructural changes can range from mild deterioration to significant degradation. In this paper, the effects of thermal exposures at temperatures from 1200 to 1600°F for durations up to one year on the mechanical properties of three wrought gas turbine alloys will be reported. The alloys will include HAYNES® 188 alloy (Co-Ni-Cr-W), HAYNES 230® alloy (Ni-Cr-W), and HAYNES HR-120® alloy (Fe-Ni-Cr-Nb-N).

Mechanical Properties of Some Si3N4 Automotive Gas Turbine Rotor Ceramics

1993 ◽  
Vol 89-91 ◽  
pp. 535-540 ◽  
Author(s):  
Ján Dusza ◽  
T. Lube ◽  
Robert Danzer ◽  
K.-L. Weisskopf
Keyword(s):  
Mechanical Properties ◽  
Gas Turbine ◽  
Turbine Rotor

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 Mechanical Properties of Cement-Treated Soil Mixed with Cellulose Nanofibre

2021 ◽  
Vol 11 (14) ◽  
pp. 6425
Author(s):  
Hidenori Takahashi ◽  
Shinya Omori ◽  
Hideyuki Asada ◽  
Hirofumi Fukawa ◽  
Yusuke Gotoh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Geotechnical Engineering ◽  
Strength Development ◽  
Soft Ground ◽  
Wood Cellulose ◽  
Treated Soil ◽  
Made In ◽  
Cement Treatment

Cellulose nanofibre (CNF), a material composed of ultrafine fibres of wood cellulose fibrillated to nano-order level, is expected to be widely used because of its excellent properties. However, in the field of geotechnical engineering, almost no progress has been made in the development of techniques for using CNFs. The authors have focused on the use of CNF as an additive in cement treatment for soft ground, where cement is added to solidify the ground, because CNF can reduce the problems associated with cement-treated soil. This paper presents the results of a study on the method of mixing CNF, the strength and its variation obtained by adding CNF, and the change in permeability. CNF had the effect of mixing the cement evenly and reducing the variation in the strength of the treated soil. The CNF mixture increased the strength at the initial age but reduced the strength development in the long term. The addition of CNF also increased the flexural strength, although it hardly changed the permeability.

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