Materials for Ultrasupercritical Coal Power Plants - Boiler Materials: Part II

Viswanathan, R.; Bakker, W.

doi:10.1361/105994901770345402

Cited by 130 publications

(63 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These have been used to date in relatively short term applications such as turbine engines in the aerospace industry. Forecasted requirements for USC applications have set the targets at minimum creep strength of 100 MPa at 100000 h of service [1][2][3][4][5][6][7]. Since the microstructure of most of the candidate nickel base alloys has not been investigated after such long exposure periods of time, modelling activity has proven to be helpful in predicting the material microstructural response under simulated service conditions [8].…”

Section: Introductionmentioning

confidence: 99%

Characterisation of microstructure and creep properties of alloy 617 for high-temperature applications

Martino

Faulkner

Hogg

et al. 2014

Materials Science and Engineering: A

View full text Add to dashboard Cite

Current energy drivers are pushing research in power generation materials towards improved efficiency and improved environmental impact. In the context of new generation ultra-supercritical (USC) power plant , this is represented by increased efficiency, service temperature reaching 750 o C, pressures in the range of 35 -37.5 MPa and associated carbon capture technology. Ni base alloys are primary candidate materials for long term high temperature applications such as boilers. The transition from their current applications, which have required lower exposure times and milder corrosive environments, requires the investigation of their microstructural evolution as a function of thermo-mechanical treatment and simulated service conditions, coupled with modelling activities that are able to forecast such microstructural changes. The lack of widespread microstructural data in this context for most nickel base alloys makes this type of investigation necessary and novel. Alloy INCONEL 617 is one of the Ni-base candidate materials. The microstructures of four specimens of this material crept at temperatures in the 650 o C-750 o C range for up to 20000 h have been characterised and quantified. Grain structure, precipitate type and location, precipitate volume fraction, size and inter-particle spacing have been determined. The data obtained are used both as input for and validation of a microstructurally-based CDM model for forecasting creep properties.

show abstract

Section: Introductionmentioning

confidence: 99%

Characterisation of microstructure and creep properties of alloy 617 for high-temperature applications

Martino

Faulkner

Hogg

et al. 2014

Materials Science and Engineering: A

View full text Add to dashboard Cite

show abstract

“…1) A recently developed 10% Cr steel with Co, W, Mo additives and increased B content is a new-generation of steels for use in components of steam turbines, such as rotors and blades, exhibiting improved creep properties compared to commercial P92 steel. 2,3) Superior creep strength of this steel is attributed to the high coarsening resistance of M 23 C 6 located at the lath/(sub)grain boundaries and uniformly distributed MX precipitates during long-term aging and under creep conditions. 3,4) This dispersion of secondary phase particles effectively stabilizes the tempered martensite lath structure (TMLS) under exploitation conditions.…”

Section: Introductionmentioning

confidence: 89%

Low Cycle Fatigue Behavior of a 10% Cr Martensitic Steel at 600°C

2015

View full text Add to dashboard Cite

“…As mentioned previously, the U.S. A-USC steam program will need to use Ni-base alloys in both the boiler tubing and steam turbine in order to meet the ~350 bar (5,000 psi) and 760°C operating goals [1,2]. Steam testing has been performed at a variety of temperatures and pressures to better understand the effect of steam on candidate materials [33].…”

Section: Oxidation In Steam and Effect Of Microstructurementioning

confidence: 99%

“…Figure 7 shows data collected for alloy 718 and 718Plus in 17bar steam at 800°C. Unlike the wet air environment, little free O 2 is available to form CrO 2 (OH) 2 . Thus, a mass gain was observed, unlike the mass loss observed in 1 bar wet air [27].…”

Section: Oxidation In Steam and Effect Of Microstructurementioning

confidence: 99%

“…However, one of the primary strategies for increasing efficiency is higher temperatures, which can cause decreased component lifetimes or trigger new degradation mechanisms, sometimes requiring new, more expensive material solutions. A good example is the potential transition to Ni-base alloys for advanced ultra-super-critical (A-USC) steam boilers [1,2]. New system requirements for reduced emissions, carbon capture, or use of biofuels or opportunity fuels also can create new operating environments, sometimes referred to as "extreme" environments.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Oxidation of Superalloys in Extreme Environments

Pint¹,

Unocic²,

Dryepondt³

2010

7th International Symposium on Superalloy 718 and Derivatives (2010)

View full text Add to dashboard Cite

With the current interest in increased efficiency and reduced emissions, materials in power generation systems are increasingly exposed to more aggressive environments and higher temperatures. It is important to understand how these environments can increase corrosion rates, possibly reducing performance and likely shortening component lifetimes. Superalloys like 718 and its derivatives primarily rely on the formation of an external Cr-rich oxide layer or scale for environmental protection at typical application temperatures (≤700°C). While many laboratory oxidation and creep experiments are conducted in ambient air, the application environment for these alloys often involves combustion products, such as H 2 O and CO-CO 2 . The effect of these environments is not completely understood, especially the impact of long-term exposures, typically required of superalloy components in turbines. Air and fuel impurities, especially S and Na, can result in accelerated degradation such as the well known hot corrosion attack. While the effect of environment on crack growth has been studied, less information is available on the effect of environment on creep and fatigue properties. Initial work is being conducted to better understand the role of environment on creep properties, eventually including in-situ testing. Examples are given from steam and wet air environments and comparisons of different superalloy compositions with cast versus wrought microstructures.

show abstract

Materials for Ultrasupercritical Coal Power Plants - Boiler Materials: Part II

Cited by 130 publications

References 0 publications

Characterisation of microstructure and creep properties of alloy 617 for high-temperature applications

Characterisation of microstructure and creep properties of alloy 617 for high-temperature applications

Low Cycle Fatigue Behavior of a 10% Cr Martensitic Steel at 600°C

Oxidation of Superalloys in Extreme Environments

Contact Info

Product

Resources

About