Alloy Design of Martensitic 9Cr-Boron Steel for A-USC Boiler at 650 °C — Beyond Grades 91, 92 and 122

Abe, Fujio; Tabuchi, Masaaki; Tsukamoto, Shiro

doi:10.1007/978-3-319-48765-6_13

Cited by 10 publications

(7 citation statements)

References 10 publications

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“…Consequently, residual carbon during austenisation in P91B-ICHAZ should have formed fine M 23 C 6 carbides [34]. Henceforth, it also explains the distribution of fine M 23 C 6 carbides that stabilise martensitic lath structure and suppress type IV failure in boron modified 9Cr weldments [11,13,14].…”

Section: Evolution Of Microstructurementioning

confidence: 99%

“…It is claimed that kinetics of phase transformation is altered in HAZ during welding due to such minute concentration of boron [12]. Studies have also revealed stabilisation of lath martensitic structure and M 23 C 6 carbides in HAZ of weldments of boron modified P91-steel [13,14]. For understanding mechanisms related to improvements in microstructure at ICHAZ leading to enhanced creep performance on boron additions to P91-steel, attempts are still being given [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

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Microstructural investigations on simulated intercritical heat-affected zone of boron modified P91-steel

Khajuria

Ахтар

Bedi

et al. 2020

Materials Science and Technology

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Conventional P91 and boron modified P91-steels were considered in the present investigation. Using Gleeble, weld intercritical heat-affected zone (ICHAZ) was processed. Conventional microscopy was done along with electron back-scattered diffraction for both specimens. Lath boundary of martensite was more, and preferably oriented for P91B-ICHAZ than P91-ICHAZ. Lattice strain was high and lath mobility was low for P91B-ICHAZ in comparison to P91-ICHAZ. Large fraction of ferritic grain structure (39.1%) and small fraction of fresh martensitic grain structure (9.5%) in P91-ICHAZ, whereas small fraction of ferritic grain structure (10.7%) and large fraction of fresh martensitic grain structure (32.7%) in P91B-ICHAZ was observed. However, tempered martensite exhibited meager variation. These differences between ICHAZ simulations were attributed to the presence of 100ppm-boron in P91B-steel.

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Section: Evolution Of Microstructurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microstructural investigations on simulated intercritical heat-affected zone of boron modified P91-steel

Khajuria

Ахтар

Bedi

et al. 2020

Materials Science and Technology

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“…Creep testing results for weld 1 (MARBN heat 1) and weld 2 (MARBN heat 2) crosswelds tested at 650°C compared to corresponding MARBN base material heats and gradeP92 base material 36 and welded joints 37 …”

Section: Resultsmentioning

confidence: 99%

Creep and damage investigation of advanced martensitic chromium steel weldments for high temperature applications in thermal power plants

Schlacher

Béal

Sommitsch

et al. 2015

Science and Technology of Welding and Joining

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With the aim to increase base material creep strength and overcome the type IV cracking problem, a new design concept was developed. This so called martensitic boron-nitrogen strengthened steel (MARBN) combines boron strengthening through solid solution with precipitation strengthening by finely dispersed nitrides. In this work, uniaxial creep tests of the MARBN base material and welded joints have been carried out. The creep strength of the welded joints was analysed, and the evolution of creep damage was investigated. The creep tests of MARBN revealed increased strength of the base material of about z20% compared to the best commercially available 9Cr steel grade. At higher stress levels, the creep strength of crosswelds is between that of the MARBN base material and the conventional 9Cr base materials. Nevertheless, long term creep tests revealed a drop in creep strength of the MARBN welded joints. The underlying phenomena of crossweld creep behaviour are discussed in detail.

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“…BN particles reduce creep ductility that deteriorates creep strength at long times [64]. Abe et al established that the BN particles are responsible for the degradation in reduction of area (RA) at low stresses and long times by accelerating the formation of creep voids at interfaces between the BN particles and alloy matrix [65].…”

Section: The Boron/nitrogen Ratio In the Steelsmentioning

confidence: 99%

9–12% Cr Heat-Resistant Martensitic Steels with Increased Boron and Decreased Nitrogen Contents

Dudova

2022

Metals

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As a promising alloying approach, the modification of chemical composition by increasing the B content and decreasing the N content has been applied to improve the creep resistance of various 9–12% Cr heat-resistant martensitic steels. This paper presents an overview of the creep strength and related microstructural features of the 9% Cr and 10–12% Cr martensitic steels with high B and low N contents. The factors that determine the optimal B/N ratio in steels are considered. The creep properties are compared with those for similar steels with conventional B and N contents. The relationships between the stability of lath structure and precipitates of M23C6, Laves, and MX phases and the creep strength of steels are considered. Further perspectives of this modification of alloying by high boron and low nitrogen are outlined.

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Alloy Design of Martensitic 9Cr-Boron Steel for A-USC Boiler at 650 °C — Beyond Grades 91, 92 and 122

Cited by 10 publications

References 10 publications

Microstructural investigations on simulated intercritical heat-affected zone of boron modified P91-steel

Microstructural investigations on simulated intercritical heat-affected zone of boron modified P91-steel

Creep and damage investigation of advanced martensitic chromium steel weldments for high temperature applications in thermal power plants

9–12% Cr Heat-Resistant Martensitic Steels with Increased Boron and Decreased Nitrogen Contents

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