Interactions between Superalloys and Mould Materials for Investment Casting of Turbine Blades

2010 ◽  
Vol 70 ◽  
pp. 130-135 ◽  
Author(s):  
Fabrizio Valenza ◽  
Rafal Nowak ◽  
Natalia Sobczak ◽  
Alberto Passerone ◽  
Michele Di Foggia ◽  
...  
Keyword(s):  
Investment Casting ◽  
Gas Turbines ◽  
Sessile Drop ◽  
Turbine Blades ◽  
Casting Process ◽  
Ceramic Materials ◽  
Processing Parameters ◽  
Industrial Gas Turbines ◽  
Materials Used ◽  
Manufacturing Technologies

The need of increased efficiency of industrial gas turbines comes also through the improvement of the composition of superalloys (addition of new solutes) and of the manufacturing technologies involved in the investment casting process of the turbine blades. Thus, the knowledge of the interactions between the ceramic materials used for casting and the molten superalloys must be deepened in order to minimize the formation of internal defects, to improve the casting surface and to optimize finishing and casting operations. In this work, a study of the wetting behaviour of some Ni- or Co -based superalloys, used for the fabrication of turbine blades, has been performed with reference to the interactions of these alloys in the molten state with the silica-aluminate based ceramic materials forming the shell or the core in the casting process. Wettability tests have been performed by means of the sessile drop method at 1500°C; the characterization of the interfaces between the molten drop and the substrates has been made on solidified sessile drop samples by SEM/EDS analysis to check the final characteristics of the interfaces. The results are discussed in terms of chemical interactions in relation to the processing parameters and as a function of the surface and interfacial energetic properties of the systems.

Optimization of Coating Materials Used on Expandable Polystyrene Pattern in Investment Casting Process

2013 ◽  
Vol 3 (2) ◽  
pp. 21-32 ◽  
Author(s):  
Girendra Bhati ◽  
◽  
Sudhir Kumar ◽  
Ajay Kumar ◽  
Daizy Rajput ◽  
...  
Keyword(s):  
Investment Casting ◽  
Casting Process ◽  
Coating Materials ◽  
Expandable Polystyrene ◽  
Investment Casting Process ◽  
Materials Used

Some Aspects of Operated Blades HCF Analysis: Rejuvenation and Life Estimation

2018 ◽  
Author(s):  
Sergey A. Ivanov ◽  
Maxim G. Guralnik ◽  
Alexander I. Rybnikov
Keyword(s):  
Shot Peening ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Life Extension ◽  
Ultrasonic Shot Peening ◽  
Industrial Gas Turbines ◽  
Hcf Strength ◽  
Blade Failure ◽  
Metal Properties ◽  
The Cost

The lifecycle of modern industrial gas turbines can reach hundred thousand hours and usually the turbine blades need to be replaced. The use of super alloys and application of advanced coatings makes the cost of turbine lifecycle rather high. The methods for blade rejuvenation and life extension are based on the analysis of the main defects which can considerably reduce blade strength. The effect of long operation and typical defects in turbine blades has been studied in correlation with HCF. The decrease of blades HCF under the effect of operation has been considered as the result of influence of mechanical and thermal factors. The influence of FOD on the blade HCF strength is studied. Some random defects in turbine blades which resulted in HCF decreasing and blade failure are considered. The rejuvenation heat treatment for the blades of ZhS6K and EI893 and its positive effect on metal properties is demonstrated. The ultrasonic shot peening for operated blades have been considered. It is demonstrated that HCF strength of blades after shot peening is about 25–30% higher. Relaxation of compressing stresses in operation is shown as not essential. The remaining life of operated blades can be estimated using the correlation of endurance limit and run time.

Optimization of investment casting parameters for reduction of shrinkage porosity in nickel-based superalloy castings by Taguchi method

2021 ◽  
pp. 2150136
Author(s):  
Peng Zhang ◽  
Guohuai Liu ◽  
Ye Wang ◽  
Shiping Wu ◽  
Zhaodong Wang
Keyword(s):  
Taguchi Method ◽  
Investment Casting ◽  
Signal To Noise Ratio ◽  
Casting Process ◽  
Processing Parameters ◽  
Shrinkage Porosity ◽  
Pouring Temperature ◽  
Nickel Based Superalloy ◽  
Preheating Temperature ◽  
Processing Optimization

In order to improve the castings quality of nickel-based superalloy in investment casting process, especially to reduce the shrinkage porosity, the processing parameters were optimized by numerical simulation and Taguchi method. The effects of processing parameters, such as pouring temperature, pouring time and mold shell preheating temperature, on the shrinkage porosity in the turbine nozzle investment castings prepared by K477 nickel-based superalloy were investigated. The results show that the effects of the mold shell preheating temperature, pouring temperature and pouring time are main influencing factors in turn, which are verified by the evaluation of signal-to-noise ratio and the analysis of variance. Further, based on the processing optimization, a K477 alloy turbine nozzle without shrinkage porosity was prepared with the optimized parameters: pouring temperature of 1450[Formula: see text]C, mold shell preheating temperature of 1050[Formula: see text]C and pouring time of 14 s, respectively.

A New Analytical Model for Interpreting the Wear Mechanisms of Abradable Seal Systems and Verification by Testing

1989 ◽  
Author(s):  
J. Soehngen
Keyword(s):  
Heat Flux ◽  
High Temperature ◽  
Analytical Model ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Ceramic Materials ◽  
Analytical Prediction ◽  
Material Loss ◽  
Blade Tip ◽  
Engine Components

In order to minimize the specific fuel consumption of gas turbines it is necessary to increase the gas temperatures and pressure ratios. Therefore, new high-temperature resistant abradable seal systems must be developed, especially for the hot section. Since the required operating temperatures are above 1050°C, the use of metallic materials as abradables is out of the question. A problem commonly encountered in the selection of new (ceramic) materials for seal systems is that of insufficient knowledge of the tribological process occurring when turbine blades rub against an abradable seal. The purpose of the investigation was to find a simplified analytical model to describe the tribological process occurring in the rubbing of the blades against the seal, in order to help in the preselection of materials for abradable seals. The model was verified by testing high-temperature resistant abradable seals under simulated engine conditions, followed by metallurgical examination. The results of the examination of two abradable seals on run engine components confirmed the analytical prediction and laboratory tests. The differences in material loss from the blade and the abradable seal can be correlated to the heat flux distribution in the sliding parts. Using different materials on the blade tip and stationary seal (e.g. ceramic blade tip and ceramic or metallic abradable seal), the heat flux can be directed in such a way that the wear takes place largely on the static part of the engine. By calculating their relative abradability, material combinations with optimum performance for each seal application can be found.

Development and Testing of Harsh Environment, Wireless Sensor Systems for Industrial Gas Turbines

2009 ◽  
Author(s):  
David Mitchell ◽  
Anand Kulkarni ◽  
Alex Lostetter ◽  
Marcelo Schupbach ◽  
John Fraley ◽  
...  
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Operating Conditions ◽  
Condition Based Maintenance ◽  
Harsh Environment ◽  
Sensor Systems ◽  
Wireless Telemetry ◽  
Industrial Gas Turbines

The potential for savings provided to worldwide operators of industrial gas turbines, by transitioning from the current standard of interval-based maintenance to condition-based maintenance may be in the hundreds of millions of dollars. In addition, the operational flexibility that may be obtained by knowing the historical and current condition of life-limiting components will enable more efficient use of industrial gas turbine resources, with less risk of unplanned outages as a result of off-parameter operations. To date, it has been impossible to apply true condition-based maintenance to industrial gas turbines because the extremely harsh operating conditions in the heart of a gas turbine preclude using the necessary advanced sensor systems to monitor the machine’s condition continuously. Siemens, Rove Technical Services, and Arkansas Power Electronics International are working together to develop a potentially industry-changing technology to build smart, self-aware engine components that incorporate embedded, harsh-environment-capable sensors and high temperature capable wireless telemetry systems for continuously monitoring component condition in the hot gas path turbine sections. The approach involves embedding sensors on complex shapes, such as turbine blades, embedding wireless telemetry systems in regions with temperatures that preclude the use of conventional silicon-based electronics, and successfully transmitting the sensor information from an environment very hostile to wireless signals. The results presented will include those from advanced, harsh environment sensor and wireless telemetry component development activities. In addition, results from laboratory and high temperature rig and spin testing will be discussed.

Collapsibility Studies of MJM Acrylate Patterns for Investment Casting

2013 ◽  
Vol 330 ◽  
pp. 839-842
Author(s):  
O.M.F. Marwah ◽  
S. Sharif ◽  
M. Ibrahim ◽  
M.H. Idris
Keyword(s):  
Investment Casting ◽  
Cost Reduction ◽  
Lead Time ◽  
Casting Process ◽  
Ash Content ◽  
Ceramic Mold ◽  
Significant Cost ◽  
Volume Production ◽  
Materials Used ◽  
Significant Cost Reduction

Direct rapid investment casting (IC) is among the favorable and economical casting process due to its flexibility in fabricating any geometrical part features within a shorter lead time. Polymer based materials used in rapid prototyping (RP) technologies are exhibiting significant cost reduction for low volume production and are potentially replacing conventional wax materials as sacrificial patterns in IC process. This paper reports on the collapsibility characteristics of acrylate patterns during the burnout process for IC molds. The acrylate based patterns were fabricated by a Multijet Modelling (MJM) process with hollow internal structure. The MJM patterns were then Slurry procedure were introduced for producing toughest ceramic mould to prevent cracking occurrence. Results showed that the acrylate patterns start to decomposed gradually from the ceramic mold at 350°C and at 600°C, a total clean burnout without any residues and ash content was attained. This study shows that acrylate patterns built from RP technologies are suitable for fabricating ceramic molds and are highly potential in substituting conventional wax for IC process.

Turbine Tip Clearance Measurement System Evaluation on an Industrial Gas Turbine

1997 ◽  
Author(s):  
S. J. Gill ◽  
M. D. Ingallinera ◽  
A. G. Sheard
Keyword(s):  
Gas Turbine ◽  
Measurement System ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Tip Clearance ◽  
Real Time Measurement ◽  
Gap Measurement ◽  
Industrial Gas Turbines ◽  
Blade Tip ◽  
Industrial Gas Turbine

The continuing development of industrial gas turbines is resulting in machines of increasing power and efficiency. The need to continue this trend is focusing attention on minimizing all loss mechanisms within the machine, including those associated with turbine blade tip clearance. In order to study tip clearance in the turbine, real time measurement is required of clearance between turbine blades and the casing in which they run. This measurement is not routinely performed, due to the harsh nature of the turbine environment. On those occasions when turbine tip clearance is measured, it is typically in development vehicles, often using cooled probes that are somewhat unsuitable for use in production gas turbines. In this paper a program of work is reported that was undertaken with the purpose of identifying a promising turbine tip clearance measurement system that used the capacitive gap measurement technique. Issues surrounding the application of three systems to the turbine section of a GE MS6001FA gas turbine are identified and reported. Performance of the three evaluated systems is analyzed.

scholarly journals Effects of Alloy Composition on the Performance of Yttria Stabilized Zirconia–Thermal Barrier Coatings

1999 ◽  
Author(s):  
Josh Kimmel ◽  
Zaher Mutasim ◽  
William Brentnall
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Gas Turbines ◽  
Base Alloy ◽  
Critical Factor ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Turbine Component ◽  
Industrial Gas Turbines ◽  
Materials Used

Thermal barrier coatings (TBCs) provide an alloy surface temperature reduction when applied to turbine component surfaces. Thermal barrier coatings can be used as a tool for the designer to augment the power and/or enhance the efficiency of gas turbine engines. TBCs have been used successfully in the aerospace industry for many years, with only limited use for industrial gas turbine applications. Industrial gas turbines operate for substantially longer cycles and time between overhauls, and thus endurance becomes a critical factor. There are many factors that affect the life of a TBC including the composition and microstructure of the base alloy and bond coating. Alloys such as Mar-M 247, CMSX-4 and CMSX-10 are materials used for high temperature turbine environments, and usually require protective and/or thermal barrier coatings for increased performance. Elements such as hafnium, rhenium, and yttrium have shown considerable improvements in the strength of these alloys. However these elements may result in varying effects on the coatability and environmental performance of these alloys. This paper discusses the effects of these elements on the performance of thermal barrier coatings.

Investigation of the Effect of Solidification Velocity on the Quality of Single Crystal Turbine Blades

2013 ◽  
Vol 372 ◽  
pp. 54-61 ◽  
Author(s):  
Ekaterina Rzyankina ◽  
Dariusz Szeliga ◽  
Nawaz Mahomed ◽  
Andrzej Nowotnik
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
High Temperatures ◽  
Investment Casting ◽  
Gas Turbines ◽  
New Technologies ◽  
Solidification Rate ◽  
Turbine Blades ◽  
Solidification Velocity

The occurrence of high temperatures in combustion chambers of jet engines and gas turbines has led to the demand for new technologies and new materials for the manufacture of one of the most critical elements of these systems - the turbine blades. These elements have to withstand extreme temperatures for extended periods without loss of mechanical strength, conditions under which many alloys fail. Such failure is ascribed to the combination of high temperatures and high centrifugal forces, resulting in creep. This is especially prevalent in multi-crystalline structures in which grain boundaries present weaknesses in the structure. High temperature resistant alloys formed as single crystal (SX) structures offer the necessary material properties for safe performance under such extreme conditions. Modelling and simulation techniques were first used to study the directional solidification (DS) of crystal structures during vacuum investment casting. These models allowed the study of the dendritic growth rate, the formation of new grains ahead of the solid/liquid interface and the morphology of the dendritic microstructure. These studies indicated the opportunity to optimise the velocity of the solidification front (solidification rate) for single crystal structures. The aim of this study was therefore to investigate the effect of the solidification rate on the quality of SX castings. The investigations were carried out for nickel-based superalloy CMSX-4 turbine blade casts and rods using the Bridgman process for vacuum investment casting.

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