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

Chi, Chengyu; Yu, Hongying; Xie, Xiangyu

doi:10.5772/28412

Cited by 18 publications

(32 citation statements)

References 21 publications

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“…This steel was developed as a result of modification of the chemical composition of steel 310 by adding the niobium and nitrogen microadditions and by optimizing the nickel content, which resulted in the growth of high-temperature creep strength and creep resistance while maintaining very high heat resistance. High creep resistance and very good resistance to high-temperature corrosion and oxidation in steam make the HR3C steel the recommended material for the elements of supercritical power units, such as, but not limited to, boiler superheaters working at 650-660 • C [1,2].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Service on Microstructure and Mechanical Properties of HR3C Heat-Resistant Austenitic Stainless Steel

et al. 2020

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The physical metallurgical tests were performed on the test samples made of HR3C steel, taken from a section of a pipeline in the as-received condition and after approximately 26,000 h of service at 550 °C. In the as-received condition, the test material had austenitic microstructure with numerous large primary Z-phase precipitates inside the grains. The service of the test steel mainly contributed to the precipitation processes inside the grains and at the grain boundaries. After service, the following precipitates were identified in the microstructure of the test steel: Z-phase (NbCrN) and M23C6 carbides. The Z-phase precipitates were observed inside the grains, whereas M23C6 carbides - at the boundaries where they formed the so-called continuous grid. The service of the test steel contributed to the growth of the strength properties, determined both at room and elevated temperature (550, 600 °C), compared to the as-received condition. Moreover, the creep properties of HR3C steel after service were higher than those of the material in the as-received condition. The increase in the strength properties and creep resistance was connected with the growth of strengthening of the test steel by the precipitation of Z-phase and M23C6 carbides.

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Section: Introductionmentioning

confidence: 99%

The Effect of Service on Microstructure and Mechanical Properties of HR3C Heat-Resistant Austenitic Stainless Steel

et al. 2020

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“…Similarly to ferritic steels, the development of austenitic steels was mainly the result of the optimisation and modification of chemical composition of the currently used steels [1][2][3][4]. One of the new grades of creep-resisting austenitic steels that have been introduced into the energy sector is HR3C steel.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and mechanical properties of HR3C austenitic steel after service

Golański

Kolan

Zieliński

et al. 2016

Archives of Materials Science and Engineering

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Purpose: The purpose of the investigations was to determine changes in the microstructureand mechanical properties of HR3C creep resisting austenitic steel after service.Design/methodology/approach: The investigations were performed on test specimens takenfrom a part of the steam superheater tube. The range of the investigations included: microstructuralinvestigations - light and SEM microscope; analysis of precipitates - carbide isolates; investigationsof mechanical properties - hardness measurement, static tensile test, impact test.Findings: The precipitation processes at the grain boundaries lead to increase inintergranular corrosion of the HR3C steel resulting in loss of grains in the structure. Theimpact strength testing on test specimens with reduced width may result in overestimationof crack resistance of the material after service.Research limitations/implications: The comprehensive analysis of precipitationprocesses requires TEM examinations. Finding the correlation between the impact strengthdetermined on standard vs. non-standard test specimens with reduced width.Practical implications: The obtained results of investigations are used in industrialpractice for diagnosis of pressure parts of power boilers. Test procedures developed based oncomprehensive materials testing conducted under laboratory conditions are used in upgradingand design of pressure parts of steam boilers. The results of investigations are also the elementof database of the materials characteristics of steels and alloys as well as welded joints made ofthem working under creep conditions developed by the Institute for Ferrous Metallurgy.Originality/value: The results and analysis of the investigations of microstructure andmechanical properties of HR3C steel after service under actual boiler conditions are presented.

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“…In the middle of nineties, a return to the construction of supercritical blocks was made, which contributed to the works to be carried out on the application of new austenitic alloy steels and alloys. The Inconel 740H is a derivative of the Nimonic 263 alloy, which in its initial development led to the Inconel 740 alloy, followed by the modernization of the chemical composition (optimisation of the concentration between Nb, Ti, Al and Bi, Si reduction) to Inconel 740H [16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Long-Term Ageing on the Degradation of the Microstructure the Inconel 740h Alloy

et al. 2020

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The Inconel 740H alloy is used in the construction of pressure components of ultra-supercritical operating parameters. The paper presents the results of microstructure analysis after 1000 and 10 000 h ageing at 700 and 750 • C. Microstructure studies were made using scanning and transmission electron microscopy. Identification of precipitations was made using X-ray analysis of phase composition. The influence of ageing time on changes in microstructure and the precipitation process of the tested alloy were described. Presented research results are a material characteristic of new generation materials, which are used in the design of elements of pressure parts of boilers and diagnostics work during operation.

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

Cited by 18 publications

References 21 publications

The Effect of Service on Microstructure and Mechanical Properties of HR3C Heat-Resistant Austenitic Stainless Steel

The Effect of Service on Microstructure and Mechanical Properties of HR3C Heat-Resistant Austenitic Stainless Steel

Microstructure and mechanical properties of HR3C austenitic steel after service

The Effect of Long-Term Ageing on the Degradation of the Microstructure the Inconel 740h Alloy

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