scholarly journals Up-Scaling of Thermomechanically Induced Laves Phase Precipitation in High Performance Ferritic (HiperFer) Stainless Steels

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1635
Author(s):  
Jana Pöpperlová ◽  
Xiuru Fan ◽  
Bernd Kuhn ◽  
Ulrich Krupp
Keyword(s):  
Stainless Steels ◽  
Power Plants ◽  
Thermal Power ◽  
Laves Phase ◽  
Laboratory Scale ◽  
Particle Analysis ◽  
Strengthening Effect ◽  
Sem Images ◽  
Thermomechanical Process ◽  
Up Scaling

Fully ferritic stainless steels, strengthened by Laves phase precipitates, were developed for high-temperature application in the next generation of ultra-super-critical thermal power plants. Based on the rapid occurrence of thermomechanically induced precipitation in strengthening Laves phase particles, a novel thermomechanical process route for this class of steels was developed. A controlled precipitation of particles, in a desired morphology and quantity, and an optimization of the corresponding forging parameters was achieved on a laboratory scale. This article outlines the very first up-scaling experiment with these optimized forging parameters from the laboratory scale to the industrial scale. The precipitation behavior was analyzed, utilizing digital particle analysis of scanning electron microscopy (SEM) images, to estimate and compare the phase fraction of the precipitated Laves phase, as well as the particle size and distribution. Due to the up-scaling in the forging process, the behavior of the precipitation changed and the precipitation strengthening effect was decreased, in comparison with the laboratory scale.

scholarly journals Impact of Tungsten on Thermomechanically Induced Precipitation of Laves Phase in High Performance Ferritic (HiperFer) Stainless Steels

2020 ◽  
Vol 10 (13) ◽  
pp. 4472 ◽  
Author(s):  
Jana Pöpperlová ◽  
Xiuru Fan ◽  
Bernd Kuhn ◽  
Wolfgang Bleck ◽  
Ulrich Krupp
Keyword(s):  
Particle Size ◽  
Stainless Steels ◽  
Power Plants ◽  
Volume Fraction ◽  
Laves Phase ◽  
Particle Analysis ◽  
Strengthening Effect ◽  
Tungsten Content ◽  
High Chromium ◽  
The Impact

High-chromium ferritic stainless steels strengthened by Laves phase precipitates were developed for a high-temperature application in steam power plants. The impact of tungsten content on the precipitation of the intermetallic Laves phase during the newly developed thermomechanical process route was investigated. Due to rapid thermomechanically induced precipitation, a considerable reduction in processing time in comparison to the conventional solely thermal two-step processing of high chromium ferritic steels was achieved. Nevertheless, comparable mechanical properties at room temperature, i.e., the ultimate tensile strength of 712 MPa and the yield strength of 434 MPa, were obtained. The microstructure was analyzed by scanning electron microscopy (SEM) in combination with digital particle analysis, to estimate the particle size and the phase fraction of the Laves phase. The mean particle size of 52 nm and the volume fraction of 4.11% were achieved. Due to the tungsten content, an increase in the volume fraction and particle size was observed, giving rise to the higher strengthening effect.

scholarly journals DETERMINING THE ROLE OF INDIVIDUAL FLY ASH PARTICLES IN INFLUENCING THE VARIATION IN THE OVERALL PHYSICAL, MORPHOLOGICAL, AND CHEMICAL PROPERTIES OF FLY ASH

2016 ◽  
Vol 56 (4) ◽  
pp. 265-282 ◽  
Author(s):  
Usman Haider ◽  
Zdenek Bittnar ◽  
Lubomír Kopecky ◽  
Vít Šmilauer ◽  
Jaroslav Pokorny ◽  
...  
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Thermal Power ◽  
Chemical Properties ◽  
Cementitious Materials ◽  
Individual Particle ◽  
Particle Analysis ◽  
Fly Ashes ◽  
Alumino Silicate ◽  
Individual Particles

The properties of fly ashes vary because of the differences in the properties of their individual particles, and the determination of variation in these properties is of interest to the industries which use pulverized raw fly ash in applications, such as in cementitious materials and in the recovery of certain rare elements from raw fly ash. To investigate the differences in individual particles, four pulverized raw fly ashes from thermal power plants of the Czech Republic were used in this research. It was observed from FE-SEM that all four fly ashes consist of glassy hollow spherical, solid spherical, porous spherical, bright spherical, porous slaggy and compact slaggy particles. Box and whisker diagrams were plotted from the data of EDX individual particle analyses, which showed that the data of percentages for the Si, Al, and Fe elements is more scattered as compared to other elements. It was further observed from ternary phase diagrams and pseudo coloured images, that nature of fly ash particles changes from alumino silicate glassy to alumino silicate calcite metallic to pure ferro-metallic,where glassy particles showed high percentages and pure calcite particles were absent in fly ashes. Furthermore, a comparison between the XRF, the EDX total area analyses, showed that the EDX individual particle analysis gives more realistic and reliable data with median, mean, and the standard deviation for percentages of each element present in the fly ashes.

Power Beam Processing of Stainless Steels

2013 ◽  
Vol 794 ◽  
pp. 332-339
Author(s):  
B. Shanmugarajan ◽  
G. Buvanashekaran
Keyword(s):  
Electron Beam ◽  
Stainless Steels ◽  
Power Plants ◽  
Thermal Power ◽  
Electron Beam Processing ◽  
Industrial Sectors ◽  
Input Processing ◽  
Processing Plants ◽  
Almost All ◽  
Keywords Laser

Stainless steels are one of the versatile materials available in five grades viz., austenitic, ferritic, martensitic, duplex stainless steels and precipitation hardenable variety, having applications in various industrial sectors covering thermal power plants, nuclear, fertilizer, urea processing plants, cryogenic industries, aerospace & defence, etc. Each grade of stainless steels has its own unique characteristics in terms of strength, corrosion resistance, hardening behavior etc. Power beam processing using lasers or electron beam can be effectively utilized to process almost all the grades of stainless steels to enhance the performance for intended application. The non-contact and autogenous nature of the process coupled with precise and low heat input processing offers greater benefits compared to processing with conventional processes. This paper describes the application and advantages of power beam processing of different grades of stainless steels. Keywords: laser processing, electron beam processing, stainless steels, welding, cladding, hardening.

Complexities of In-Service Failures in Dissimilar Metal Welds Between Grade 91 and Austenitic Stainless Steels

2016 ◽  
Author(s):  
John Siefert ◽  
Jonathan Parker ◽  
Terry Totemeier
Keyword(s):  
Stainless Steels ◽  
Power Plants ◽  
Thermal Power ◽  
Austenitic Stainless Steels ◽  
Steam Pressure ◽  
Enabling Technology ◽  
Service Failures ◽  
Dissimilar Metal ◽  
Higher Temperature ◽  
Grade 91

The efficiency of thermal power plants is related to operating steam pressure and temperature. The desire to maximize performance, while minimizing emissions, provides a large incentive to introduce new power generating plants with higher temperature and pressure. Improvements to design can offer important benefits, but, a key enabling technology to greater thermal efficiency is the development and acceptance of engineering materials with superior properties. Next generation heat recovery steam generators (HRSGs) are expected to require the use of thick-section dissimilar metal welds (DMWs) due a competitive market that is rapidly pushing increases in efficiency (and therefore an increase in steam temperature). There is an increasing concern that the current, “conventional practice” for fabricating DMWs is ill-established and not optimized for applications where the ferritic material is Grade 91 steel. To address the complexity of issues associated with the performance of DMWs, a series of research studies are underway with the Electric Power Research Institute. This paper reviews a number of in-service failures arising from DMWs between Grade 22 and austenitic stainless steels and Grade 91 and austenitic stainless steels.

Recent Developments in Niobium Containing Austenitic Stainless Steels for Thermal Power Plants

2015 ◽  
pp. 271-277
Author(s):  
Mariana Perez de Oliveira ◽  
Wei Zhang ◽  
Hongyao Yu ◽  
Hansheng Bao ◽  
Xishan Xie
Keyword(s):  
Stainless Steels ◽  
Power Plants ◽  
Thermal Power ◽  
Austenitic Stainless Steels ◽  
Thermal Power Plants ◽  
Recent Developments

Properties and Experience of High Cr Austenitic Stainless Steel for Boiler Tubes

2007 ◽  
Author(s):  
Yusuke Minami ◽  
Toshihiko Fukui
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Power Plants ◽  
Rupture Strength ◽  
Thermal Power ◽  
Austenitic Stainless Steels ◽  
Environmental Resistance ◽  
Higher Temperature

Recent boilers for thermal power generation are designed for higher temperature and pressure than in the past, and substantial efforts are being made worldwide to establish technology for ultra super critical power plants. Such boilers will require the use of steels having higher strength and better corrosion resistance than conventional 18-8 austenitic stainless steels. High chromium austenitic stainless steel (22Cr-15Ni-Nb-N) has been developed as a candidate material, and creep rupture strength is more than 50% higher than ASME SA-213 Grade TP347H at 700°C. The hot corrosion and steam oxidation resistance of this steel are also superior to 18-8 stainless steels due to higher Cr content. Thirteen years practical service as superheater tubing in a power plant characterized by high pressure (35MPa) and high temperature (615&°C) has revealed that the mechanical properties and environmental resistance of this steel are sufficient for high temperature boiler tube applications.

Recent Developments in Niobium Containing Austenitic Stainless Steels for Thermal Power Plants

2014 ◽  
pp. 271-277 ◽  
Author(s):  
Mariana Perez de Oliveira ◽  
Wei Zhang ◽  
Hongyao Yu ◽  
Hansheng Bao ◽  
Xishan Xie
Keyword(s):  
Stainless Steels ◽  
Power Plants ◽  
Thermal Power ◽  
Austenitic Stainless Steels ◽  
Thermal Power Plants ◽  
Recent Developments

A Review on Utilization of Fly- Ash and Pond-Ash as a Partial Replacement of Cement in Concrete Mix Design

2018 ◽  
pp. 413-418
Author(s):  
Harshkumar Patel ◽  
Yogesh Patel
Keyword(s):  
Fly Ash ◽  
Electricity Generation ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Thermal Power ◽  
Strength Test ◽  
Partial Replacement ◽  
Pond Ash ◽  
Research Activities ◽  
Ash Disposal

Now-a-days energy planners are aiming to increase the use of renewable energy sources and nuclear to meet the electricity generation. But till now coal-based power plants are the major source of electricity generation. Disadvantages of coal-based thermal power plants is disposal problem of fly ash and pond ash. It was earlier considered as a total waste and environmental hazard thus its use was limited, but now its useful properties have been known as raw material for various application in construction field. Fly ash from the thermal plants is available in large quantities in fine and coarse form. Fine fly ash is used in construction industry in some amount and coarse fly ash is subsequently disposed over land in slurry forms. In India around 180 MT fly is produced and only around 45% of that is being utilized in different sectors. Balance fly ash is being disposed over land. It needs one acre of land for ash disposal to produce 1MW electricity from coal. Fly ash and pond ash utilization helps to reduce the consumption of natural resources. The fly ash became available in coal based thermal power station in the year 1930 in USA. For its gainful utilization, scientist started research activities and in the year 1937, R.E. Davis and his associates at university of California published research details on use of fly ash in cement concrete. This research had laid foundation for its specification, testing & usages. This study reports the potential use of pond-ash and fly-ash as cement in concrete mixes. In this present study of concrete produced using fly ash, pond ash and OPC 53 grade will be carried. An attempt will be made to investigate characteristics of OPC concrete with combined fly ash and pond ash mixed concrete for Compressive Strength test, Split Tensile Strength test, Flexural Strength test and Durability tests. This paper deals with the review of literature for fly-ash and pond-ash as partial replacement of cement in concrete.

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