scholarly journals Advanced Austenitic Heat-Resistant Steels for Ultra-Super-Critical (USC) Fossil Power Plants

10.5772/28412 ◽  
2011 ◽  
Author(s):  
Chengyu Chi ◽  
Hongyao Yu ◽  
Xishan Xie
Keyword(s):  
Power Plants ◽  
Heat Resistant ◽  
Heat Resistant Steels

Small Punch Testing and Its Modeling for the Evaluation of Mechanical Properties of Heat-Resistant Steels

2009 ◽  
Author(s):  
Petr Dyma´cˇek ◽  
Karel Milicˇka
Keyword(s):  
Material Properties ◽  
Power Plants ◽  
Residual Life ◽  
Tensile Tests ◽  
Constant Load ◽  
Material Behavior ◽  
Small Punch ◽  
Heat Resistant ◽  
Wide Range ◽  
Heat Resistant Steels

Small punch tests on miniaturized thin discs (SPT) can be considered as one of the promising methods predominantly for an assessment of the residual life of parts in service of power plants and thermal facilities. These tests can be used for determining a number of material properties. Two variations of the test seem to have a good potential for use in wide range of temperatures. The CF test (constant force) is a test in which the puncher penetrates under constant load and the time dependence of the deflection is measured. This test is similar to a conventional creep test. The CDR test (with constant deflection rate conditions), in which the puncher penetrates through the disc at a given constant rate of deflection (i.e., central deflection measured in a direction perpendicular to the disc) and the necessary force is measured. This mode of the tests can serve similarly as conventional tensile tests for determining of the static material properties, the estimation of fracture toughness and transitions in material behavior. The article summarizes the capabilities of the small punch technique and presents results from testing of two heat resistant steels, i.e., CSN 15313 and P91 used in the Czech power industry. Experimental results are compared with finite element modeling.

Introduction of L12-Ordered Precipitation to Alumina-Forming Austenitic Heat-Resistant Steels With Low Ni Content

2017 ◽  
Author(s):  
Bingbing Zhao ◽  
Xianping Dong ◽  
Feng Sun ◽  
Lanting Zhang
Keyword(s):  
High Temperature ◽  
Power Plants ◽  
Tensile Tests ◽  
Atomic Ratio ◽  
Composition Analysis ◽  
Heat Resistant ◽  
Ni Content ◽  
The Matrix ◽  
Potential Applications ◽  
Heat Resistant Steels

Alumina-forming austenitic (AFA) heat-resistant steels have been reported as a promising new class of steels in recent years with potential applications in advanced ultra-supercritical power plants. It is well known that L12-ordered γ’ phase is the most important precipitate for high-temperature strengthening in Ni-based superalloys and it can be stabilized by increasing the Ni content in heat-resistant steels. In the current work, the evolution of L12-ordered precipitates were compared in the Cu-bearing AFA alloys with 20, 27 and 35 wt.% Ni. After slow tensile tests at 700°C (∼2 × 10−5 s−1), L12-ordered precipitates occurred in all the alloys. Alloy AFA27 displayed the most densely distributed L12-particles in the matrix, whose ultimate tensile strength was also the highest. However, the L12-ordered precipitates were only observed in alloy AFA27 after the slow tensile test at 750°C due to the thermodynamic and kinetic reasons. Flow curves of slow tensile tests indicated different precipitation behaviors at 700°C and 750°C. Chemical composition analysis and thermodynamic calculation revealed that the occurrence of L12-ordered Ni-Cu-Al phase depends on temperature, Ni content and the atomic ratio of Ni/Al. This opens up new opportunities to promote the formation of L12-ordered phase in Fe-based austenitic heat-resistant steels with low Ni content and benefits high-temperature strengthening.

Development of Ferritic Heat-Resistant Steels Based on New Materials Design Concept for Advanced High Efficiency Power Plants

2015 ◽  
pp. 123-128
Author(s):  
Yoshiaki Toda ◽  
Mitsunari Auchi ◽  
Masachika Shibuya ◽  
Kota Sawada ◽  
Hideaki Kushima ◽  
...  
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Materials Design ◽  
Design Concept ◽  
New Materials ◽  
Heat Resistant ◽  
Heat Resistant Steels

Development of Ferritic Heat-Resistant Steels Based on New Materials Design Concept for Advanced High Efficiency Power Plants

2014 ◽  
pp. 123-128
Author(s):  
Yoshiaki Toda ◽  
Mitsunari Auchi ◽  
Masachika Shibuya ◽  
Kota Sawada ◽  
Hideaki Kushima ◽  
...  
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Materials Design ◽  
Design Concept ◽  
New Materials ◽  
Heat Resistant ◽  
Heat Resistant Steels

Influence of Aging on Creep Rupture Properties of Heat Resistant Steels for Steam Turbine Rotors of Thermal Power Plants

2011 ◽  
Vol 291-294 ◽  
pp. 1122-1125 ◽  
Author(s):  
Li Bin Niu ◽  
Ippei Matsushima ◽  
Tetsuji Akiu
Keyword(s):  
Steam Turbine ◽  
Power Plants ◽  
Thermal Power ◽  
Creep Rupture ◽  
Thermal Power Plants ◽  
Microstructural Stability ◽  
Heat Resistant ◽  
Turbine Rotors ◽  
Heat Resistant Steels ◽  
Rupture Properties

Influences of aging on the creep rupture properties of super-clean 9%CrMoV steel and 1%CrMoV steel, the heat resistant steels for steam turbine rotors of thermal power plants, are investigated. Using the as-received and the aging-treated materials of the two steels, creep rupture tests are carried out at 566°C. Creep rupture lives, creep fracture modes as well as the microstructural changes of the specimens are examined. It is made clear that the creep strength and the microstructural stability of super-clean 9%CrMoV steel are superior to those of 1%CrMoV steel in long-term services.

Long-Term Stabilization of Creep-Resistant Ferritic Steels for Highly Efficient Ultra-Supercritical Power Plants

2010 ◽  
Vol 72 ◽  
pp. 12-21 ◽  
Author(s):  
Fujio Abe
Keyword(s):  
Creep Strength ◽  
Power Plants ◽  
High Strength ◽  
Highly Efficient ◽  
Heat Resistant ◽  
Nickel Base ◽  
Ar Gas ◽  
Term Creep ◽  
Heat Resistant Steels

Alloy-designing of high-strength ferritic heat resistant steels has been investigated for application to highly efficient, low emission ultra-supercritical power plant with maximum steam temperature of 700 oC. Ferritic heat resistant steels can be applied to the next highest temperature components and are strongly desired to expand their temperature range up to 650 oC in order to minimize the requirement of expensive nickel base superalloys. A dispersion of nanometer size MX nitrides along boundaries and the addition of boron significantly improve long-term creep strength. Newly alloy-designed 9Cr-3W-3Co-0.2V-0.05Nb steel with 160 ppm boron and 85 ppm nitrogen exhibits excellent creep strength of base metal and no degradation in welded joints at 650 oC. The protective Cr2O3-rich scale forms on the surface of 9Cr steel by pre-oxidation treatment in Ar gas, which significantly improves the oxidation resistance in steam at 650 oC.

Recent Developments of Martensitic Heat-Resistant Steels for Ultra-Supercritical Power Plants

2019 ◽  
Vol 950 ◽  
pp. 10-14
Author(s):  
Xun Qiao ◽  
Lin Lin Wang ◽  
Xu Feng Bai
Keyword(s):  
Power Plants ◽  
Elevated Temperatures ◽  
Strengthening Mechanisms ◽  
Heat Resistant ◽  
Recent Developments ◽  
Heat Resistant Steels ◽  
Thermal Stability Of ◽  
Martensite Matrix ◽  
High Creep Resistance ◽  
Made In

This paper provides a comprehensive review of developments and progress made in martensitic heat-resistant steels, especially, with the emphasis on strengthening mechanisms used in elevated temperatures. We desired to elucidate the correlation between high creep resistance at elevated temperatures and thermal stability of nano-sized particles precipitated from martensite matrix. Finally, future prospective strengthening methods for martensitic heat-resistant steels were discussed.

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