A Comparison of Weldability, Structure, and Mechanical Properties of CM64 and Tribaloy T-800 Welds for Hard-Facing of Turbine Blades

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Mohsen K. Keshavarz ◽  
Alexandre Gontcharov ◽  
Paul Lowden ◽  
Mathieu Brochu
Keyword(s):  
Ambient Temperature ◽  
Fine Particles ◽  
Turbine Blades ◽  
Dendritic Structure ◽  
X Ray Diffraction ◽  
Turbine Engine ◽  
Haynes 230 ◽  
Gas Tungsten Arc ◽  
Distribution Of Elements ◽  
Engine Components

Abstract In this study, the weldability, microstructure, and tensile properties of CM64 and Tribaloy T-800 (T800) cobalt-based hard-facing materials were studied. Successful CM64 hard-facing could be achieved at ambient temperature using manual gas tungsten arc welding (GTAW-MA). It was shown that T800 welded at ambient temperature was prone to cold cracking due to a combination of low ductility with high welding stresses that limited the accommodation of residual stresses by plastic deformation within the weld beads. Sound T800 welds of various geometries and sizes were produced on cobalt- and nickel-based X-40 and Haynes 230 superalloys, respectively, using GTAW-MA when preheating above 900 °C was used. Microstructural analyses on the sound CM64 and T800 welds were performed using optical and electron microscopy and X-ray diffraction. The distribution of elements and phases in each alloy was evaluated and revealed the epitaxial dendritic structure with the Cr–W–Si-based phase in the interdendritic region in CM64 welds compared with petal-like and equiaxed hard Mo–Co–Si-based dendrites and fine particles in T800. Tensile testing from room temperature up to 1093 °C was performed on both alloys. T800 welds possessed lower ultimate tensile strengths and elongations in this temperature range when compared with the CM64 alloy. Recommendations for hard-facing of turbine engine components were provided.

Probabilistic High-Cycle Fretting Fatigue Assessment of Gas Turbine Engine Components

2011 ◽  
Author(s):  
Kwai S. Chan ◽  
Michael P. Enright ◽  
Patrick J. Golden ◽  
Samir Naboulsi ◽  
Ramesh Chandra ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Turbine Blades ◽  
Real Life ◽  
Fretting Fatigue ◽  
Gas Turbine Engine ◽  
Rotating Stall ◽  
Worst Case ◽  
Design Assessment ◽  
Turbine Engine ◽  
Engine Components

High-cycle fatigue (HCF) is arguably one of the costliest sources of in-service damage in military aircraft engines. HCF of turbine blades and disks can pose a significant engine risk because fatigue failure can result from resonant vibratory stresses sustained over a relatively short time. A common approach to mitigate HCF risk is to avoid dangerous resonant vibration modes (first bending and torsion modes, etc.) and instabilities (flutter and rotating stall) in the operating range. However, it might be impossible to avoid all the resonance for all flight conditions. In this paper, a methodology is presented to assess the influences of HCF loading on the fracture risk of gas turbine engine components subjected to fretting fatigue. The methodology is based on an integration of a global finite element analysis of the disk-blade assembly, numerical solution of the singular integral equations using the CAPRI (Contact Analysis for Profiles of Random Indenters) and Worst Case Fret methods, and risk assessment using the DARWIN (Design Assessment of Reliability with Inspection) probabilistic fracture mechanics code. The methodology is illustrated for an actual military engine disk under real life loading conditions.

scholarly journals The Influence of the Cooling Bores on the Dendritic Structure and Crystal Orientation in Single-Crystalline Cored CMSX-4 Turbine Blades

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3966
Author(s):  
Jacek Krawczyk ◽  
Włodzimierz Bogdanowicz
Keyword(s):  
Crystal Orientation ◽  
Turbine Blades ◽  
Dendritic Structure ◽  
X Ray Diffraction ◽  
Vertical Temperature ◽  
Single Crystalline ◽  
X Ray ◽  
Vertical Bridgman ◽  
The Relationship

Single-crystalline cored CMSX-4 blades obtained at a withdrawal rate of 3 mm/min by the vertical Bridgman method were analyzed. The dendritic structure and crystal orientation near the cooling bores of the blades were studied through Scanning Electron Microscopy, the X-ray diffraction measurements of α and β angular components of the primary crystal orientation, and the γ angular component of the secondary crystal orientation. Additionally, the primary arm spacing (PAS) was studied in areas near and far from the cooling bores. It was found that in the area approximately 3–4 mm wide around the cooling bores, changes occurred in the α, β, and γ angles, as well as in the PAS. The PAS determined for the transverse section of the root and the linear primary arm spacing (LPAS) determined for the longitudinal sections, as well as their relationship, have been defined for the areas located near the cooling bores and those at a distance from them. The vertical temperature gradient of 29.5 K/cm was estimated in the root areas located near the cooling bores based on the PAS values. The value of this gradient was significantly higher compared to the growth chamber operating gradient of 16 K/cm. The two-scale analysis applied in this study allowed for the determination of the relationship between the process of dendrite array creation proceeding on a millimeter scale, which is associated with the local changes in crystal orientation near the cooling bores, and that which proceeds on a scale of tens of millimeters, associated with the changes in crystal orientation in the whole blade cast.

Characterization of Single-Crystal Turbine Blades by X-Ray Diffraction Methods

2013 ◽  
Vol 203-204 ◽  
pp. 63-66 ◽  
Author(s):  
Włodzimierz Bogdanowicz ◽  
Robert Albrecht ◽  
Arkadiusz Onyszko ◽  
Jan Sieniawski
Keyword(s):  
Primary Dendrite ◽  
Turbine Blades ◽  
Dendritic Structure ◽  
Mapping Technique ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Structure Defects ◽  
X Ray

Characterization of structure defects in turbine blades is the basis for determination of the overall crystalline perfections. This work presents the possibilities of identifying casting defects by combining different X-ray diffraction techniques. The investigation was conducted on samples prepared from as-cast turbine blades airfoil and tips. It was found that X-ray topograms revealed dendritic structure and macro strain areas. The defects areas which have appeared on topograms were also investigated by X-ray diffraction mapping technique by EFG diffractometer. Additionally, the X-ray investigation was complemented by macro SEM images obtained by stitching several images of microstructure. The X-ray maps of misorientation angle and X-ray topograms revealed deviation between the γ’ direction and the blade axis and rotation of the primary dendrite arm around this axis.

Probabilistic High-Cycle Fretting Fatigue Assessment of Gas Turbine Engine Components

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Kwai S. Chan ◽  
Michael P. Enright ◽  
Patrick J. Golden ◽  
Samir Naboulsi ◽  
Ramesh Chandra ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Turbine Blades ◽  
Real Life ◽  
Fretting Fatigue ◽  
Gas Turbine Engine ◽  
Rotating Stall ◽  
Worst Case ◽  
Design Assessment ◽  
Turbine Engine ◽  
Engine Components

High-cycle fatigue (HCF) is arguably one of the costliest sources of in-service damage in military aircraft engines. HCF of turbine blades and disks can pose a significant engine risk because fatigue failure can result from resonant vibratory stresses sustained over a relatively short time. A common approach to mitigate HCF risk is to avoid dangerous resonant vibration modes (first bending and torsion modes, etc.) and instabilities (flutter and rotating stall) in the operating range. However, it might be impossible to avoid all the resonance for all flight conditions. In this paper, a methodology is presented to assess the influences of HCF loading on the fracture risk of gas turbine engine components subjected to fretting fatigue. The methodology is based on an integration of a global finite element analysis of the disk-blade assembly, numerical solution of the singular integral equations using the CAPRI (Contact Analysis for Profiles of Random Indenters) and Worst Case Fret methods, and risk assessment using the DARWIN (Design Assessment of Reliability with Inspection) probabilistic fracture mechanics code. The methodology is illustrated for an actual military engine disk under real life loading conditions.

Rejuvenation Heat Treatments and Their Role in the Repair of IN738 Turbine Components

2002 ◽  
Author(s):  
Warren M. Miglietti ◽  
Rich Curtis ◽  
John Helm
Keyword(s):  
Mechanical Properties ◽  
Turbine Blades ◽  
Stress Rupture ◽  
Repair Process ◽  
Heat Treatments ◽  
Turbine Engine ◽  
Heat Treated ◽  
Before And After ◽  
Metal Microstructure ◽  
Engine Components

The thermal processing of turbine engine components is a critical step in the repair and rejuvenation of turbine section hardware to ensure optimal performance and reliability. In the repair process, the thermal process regime must meet the following requirements; improving the weldability of the alloy prior to the repair process (if necessary), returning the microstructure of the alloy to a solutioned state prior to precipitation hardening the alloy, and an aging cycle in order to achieve optimal mechanical properties for the alloy. This paper will focus on the criticality of each step and discuss the typical mechanical properties seen after engine service and the repair process. We will show the importance of these steps and how they will ultimately effect the repair of the hot section component. For almost three decades, gas turbine original equipment manufacturers (OEM’s) have cast high-pressure turbine blades/buckets from In738 Ni-base superalloys. Although significant turbine experience has been gained in the use of this material, little or no standardization of repair heat treatments has been established in the industry. Currently OEM’s and component repair shops utilize a variety of refurbishment heat treatments, all targeted at achieving maximum restoration of mechanical properties and base metal microstructure. This paper also summarizes the results of stress rupture testing of service-run material both before and after six different rejuvenation heat treatments. Microstructures in the service-run and heat-treated conditions are also characterized.

scholarly journals The Quality Assurance of Cast and Wrought Aero Jet Engine Components Made from Ni-base Superalloys with Using of Quantitative Metallography Methods and Alloys Lifetime Prediction

2019 ◽  
Vol 1 (1) ◽  
pp. 222-229
Author(s):  
Juraj Belan ◽  
Lenka Kuchariková ◽  
Magdalena Mazur ◽  
Eva Tillová ◽  
Patrícia Hanusová
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Quantitative Methods ◽  
Structural Characteristics ◽  
Turbine Blades ◽  
Dendritic Structure ◽  
Lifetime Prediction ◽  
Quantitative Metallography ◽  
Jet Engine ◽  
Engine Components

Abstract The Ni-base superalloys are used in the aircraft industry for the production of aero engine most stressed parts, turbine blades or turbine discs. Quality of aero jet engine components has a significant influence on the overall lifetime of a jet engine as itself as well as the whole airplane. From this reason a dendrite arm spacing, grain size, morphology, number and value of γ′-phase are very important structural characteristics for blade or discs lifetime prediction. The methods of quantitative metallography are very often used for evaluation of structural characteristics mentioned above. The high-temperature effect on structural characteristics and application of quantitative methods evaluation are presented in this paper. The two different groups of Ni-base alloys have been used as experimental material: cast alloys ZhS6K and IN713LC, which are used for small turbine blades production and wrought alloys EI 698VD and EI 929, which are used for turbine disc production. Selected alloys have been evaluated in the starting stage and after applied heat-treatment at 850°C for 24 hrs. This applied heat-treatment causes structural changes in all alloys groups. In cast alloy dendritic structure is degraded and gamma prime average size has grown what has a negative influence on turbine blade creep rupture life. Wrought alloys show partially grain boundary melting and grain size changed due to recrystallization what causes mechanical properties decreasing – ultimate tensile strength mainly.

scholarly journals Microstructure and microhardness of nickel-base heat-resistant alloys obtained by directional and equilibrium crystallization

2019 ◽  
Vol 5 (3-4) ◽  
pp. 33-38
Author(s):  
Andriy Trostianchyn ◽  
◽  
Serhii Shvachko ◽  
Volodymyr Kulyk ◽  
Eduard Pleshakov ◽  
...  
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
X Ray Diffraction ◽  
Turbine Engine ◽  
X Ray ◽  
Heat Resistant ◽  
Operational Life ◽  
Significant Difference ◽  
Nickel Base ◽  
Engine Components

In order to determine the safe operational life of the components of gas turbine engines (GTE), introductory tests of nickel-base heat-resistant alloys (NHRA) have been performed. X-ray fluorescence and X-ray diffraction analyzes, optical microscopy and Vickers hardness measurements provided data on the phase-structural state and mechanical properties of the pristine ZhS6K-VI and ZhS32-VI alloys obtained by equilibrium and high-speed directional crystallization, respectively. Almost complete compliance of the investigated materials with the certified alloys in chemical and phase composition has been found. A significant difference in the parameters of the fragments of the microstructure of the investigated alloys, which is naturally consistent with the conditions of equilibrium and high-speed directional crystallizations, was revealed. A slightly lower anisotropy of microhardness (2.8 %), measured in transverse and longitudinal sections, was found in the ZhS6K-VI alloy as compared to the anisotropy (5.1 %) in the ZhS32-VI alloy. The obtained results will be used to test a non-destructive method for determining the safe operational life of gas turbine engine components.

Effects of Compressor Fouling and Compressor Turbine Degradation on Engine Creep Life Consumption

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Ebigenibo Genuine Saturday ◽  
Thank-God Isaiah
Keyword(s):  
Gas Turbine ◽  
Turbine Blades ◽  
Creep Life ◽  
Turbine Engine ◽  
Engine Model ◽  
Capacity Degradation ◽  
Engine Components ◽  
Stress Models ◽  
Industrial Gas Turbine ◽  
Life Consumption

The effect of engine degradation in the form of compressor fouling and compressor turbine degradation on the creep life consumption of the high-pressure (HP) turbine blades of an LM2500+ industrial gas turbine engine is investigated in this work. The degradations are flow capacity degradation and isentropic efficiency degradation. An engine model was created in Cranfield gas turbine performance and diagnostics software, pythia. Blade thermal and stress models were developed together with the Larson–Miller parameter (LMP) method for creep life analysis. The percentage decreases in creep life due to each effect were examined. For the engine considered, compressor degradation has more impact on engine creep life toward peak power operation, while HP turbine degradation has more impact on creep life at lower power levels. The results of this work will give engine operators an idea of how engine components creep life is consumed and make reasonable decisions concerning operating at part loads.

Verifying Conceptual Design Gas Turbine Blade Life Predictions by Comparison With Fleet Data

1991 ◽  
Author(s):  
John C. Bentz ◽  
Scott M. Cote
Keyword(s):  
Turbine Blades ◽  
Computer Code ◽  
Turbine Engine ◽  
Failure Data ◽  
Engine Component ◽  
The Difference ◽  
Blade Failure ◽  
Engine Components ◽  
Life Predictions ◽  
Component Failures

The Navy Engine Life Executive Routine, LIFER, is a PC based computer code which is used to assess the life of turbine engine components. The code has been developed to ascertain life for the components which have the highest wear out failure rates. The code has been successfully employed in the evaluation of a number of life-related problems for Naval aircraft engines. However, prior to this study, LIFER estimations for engine component life have not been compared to the component life as determined by component failure data. This paper presents the results of a comparison between the analytical predictions of LIFER and fleet experience for engine component failures. The comparison was made for the high pressure turbine blades of the TF34-GE-400 engine and the low pressure turbine blades of the F404-GE-400 engine. The blade failure data were analyzed using the Weibull technique. The difference between the component life, as predicted by LIFER, and the component characteristic life, as determined by the Weibull method, was less than 7.5 percent.

Thermal Analysis & Studies on Low Pressure Gas Turbine Blades Coated with Yitria Stabilized Zirconia (YSZ)

2012 ◽  
Vol 622-623 ◽  
pp. 1596-1600
Author(s):  
N. Rajasekar ◽  
P.M. Shivraj ◽  
C.J. Thomas Renald ◽  
K. Karthick ◽  
M.P. Tamizhmani
Keyword(s):  
Gas Turbine ◽  
Turbine Blades ◽  
Thermal Barrier ◽  
Stabilized Zirconia ◽  
Turbine Engine ◽  
Gas Turbine Blades ◽  
Barrier Coating ◽  
Potential Applications ◽  
Plasma Sprayed ◽  
Engine Components

The thermal barrier coatings have many potential applications in the protection of gas turbine engine components, essentially the turbine blades.In this study micro analysis was carried out on Yitria Stabilized Zirconia(YSZ) coated turbine blades and the results are compared with the uncoated blades.We have used the atmosphere plasma sprayed thermal barrier coating with a thickness of 0.25mm to withstand the high temperature of about 2000 C.We observed that by increasing the thermal coating thickness of about 0.25mm cause to increase 50% of the surface temperature of the turbine blade,which in turn increased the aero engine thrust.

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