The Effect of Ultrafine-Grained Microstructure on Creep Behaviour of 9% Cr Steel

Král, Pétr; Dvořák, Jiří; Sklenička, V.; Masuda, Takahiro; Horita, Zenji; Kuchařová, K.; Kvapilová, Marie; Svobodová, Marie

doi:10.3390/ma11050787

Cited by 17 publications

(21 citation statements)

References 62 publications

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“…Figure 5 shows the detailed microstructure of the T92 region of the investigated weldment formed of homogenized and tempered martensite, typically consisting of tempered martensitic laths inside the blocks and packets structures within prior austenitic grains. In accordance with numerous research studies focused on normalized and tempered grade 92 steels (e.g., [6][7][8][9][10][11][23][24][25]), the phase composition of the T92 steel region of the investigated weldment in its initial QT PWHT condition consists of ferrite matrix and secondary phase precipitates, namely intergranular M 23 C 6 (M = Cr, Fe, . .…”

Section: Methodssupporting

confidence: 62%

Ageing Effects on Room-Temperature Tensile Properties and Fracture Behavior of Quenched and Tempered T92/TP316H Dissimilar Welded Joints with Ni-Based Weld Metal

Čiripová

Falat

Ševc

et al. 2018

Metals

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The present work is focused on the investigation of isothermal ageing effects on room-temperature tensile properties and the failure of quenched and tempered martensitic/austenitic weldments between T92 and TP316H heat-resistant steels. The dissimilar weldments were produced by gas tungsten arc welding technique using a Ni-based Thermanit Nicro 82 filler metal. The welded joints were subjected to unconventional post-welding heat treatment consisting of the welds solutionizing (1060 °C/30 min), followed by their water quenching and final stabilization tempering (760 °C/60 min). The treatment was completed by spontaneous air cooling within a tempering furnace. The welds in their initial quenched and tempered condition were subsequently aged at 620 °C for up to 2500 h. Apart from room-temperature tensile tests performed for all the welds material states, additional cross-weld hardness measurements were carried out on longitudinal sections of broken tensile specimens. The applied thermal exposure resulted in recognizable deterioration of plastic properties, whereas their effects on strength properties were rather small. The welds tensile straining and fracture evolution exhibited competitive behavior between the austenitic TP316H region and Ni-based weld metal. The observed failure locations showed significant hardness peaks due to intensive, necking-related strain hardening effects occurred during the tensile tests.

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Section: Methodssupporting

confidence: 62%

Ageing Effects on Room-Temperature Tensile Properties and Fracture Behavior of Quenched and Tempered T92/TP316H Dissimilar Welded Joints with Ni-Based Weld Metal

Čiripová

Falat

Ševc

et al. 2018

Metals

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“…. ) carbides and intragranular MX (M = V, Nb; X = C, N) carbo-nitrides [37][38][39][40][41]. The same phase composition is to be expected also in the currently studied T92/T92 weldments in both the conventionally tempered and renormalized-and-tempered PWHT conditions.…”

Section: Microstructuressupporting

confidence: 64%

“…The phase composition of normalized and tempered martensitic steels of T/P92 grade is generally known and consists of ferritic matrix and strengthening precipitates of intergranular M 23 C 6 (M = Cr, Fe…) carbides and intragranular MX (M = V, Nb; X = C, N) carbo-nitrides [ 37 , 38 , 39 , 40 , 41 ]. The same phase composition is to be expected also in the currently studied T92/T92 weldments in both the conventionally tempered and renormalized-and-tempered PWHT conditions.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Electrolytic Hydrogenation on Mechanical Properties of T92 Steel Weldments under Different PWHT Conditions

et al. 2020

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In the present work, the effects of electrolytic hydrogen charging of T92 steel weldments on their room-temperature tensile properties were investigated. Two circumferential weldments between the T92 grade tubes were produced by gas tungsten arc welding using the matching Thermanit MTS 616 filler material. The produced weldments were individually subjected to considerably differing post-welding heat treatment (PWHT) procedures. The first-produced weldment was conventionally tempered (i.e., short-term annealed below the Ac1 critical transformation temperature of the T92 steel), whereas the second one was subjected to its full renormalization (i.e., appropriate reaustenitization well above the T92 steel Ac3 critical transformation temperature and subsequent air cooling), followed by its conventional subcritical tempering. From both weldments, cylindrical tensile specimens of cross-weld configuration were machined. The room-temperature tensile tests were performed for the individual welds’ PWHT states in both hydrogen-free and electrolytically hydrogen-charged conditions. The results indicated higher hydrogen embrittlement susceptibility for the renormalized-and-tempered weldments, compared to the conventionally tempered ones. The obtained findings were correlated with performed microstructural and fractographic observations.

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“…The increase of Al content in the studied range from 0.3 wt.% to 5.5 wt.% enhances the recrystallization ability of the grades after thermo-mechanical treatment of high temperature rolling. A larger grain size with smaller portion of grain boundaries is favorable for creep properties of the alloy [4,44]. The influence of rolling temperature of thermo-mechanical treatment and of Al content between 4-11 wt.% is described in the separated study [45].…”

Section: Description Of the Microstructure Of As-annealed Ods Alloysmentioning

confidence: 99%

The Influence of Aluminum Content on Oxidation Resistance of New-Generation ODS Alloy at 1200 °C

Stratil

Horník

Dymáček

et al. 2020

Metals

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The aim of the paper is to evaluate the effect of aluminum content on the oxidation resistance of new-generation of oxide dispersion strengthened (ODS) alloy at 1200 °C. Three grades of the alloy of chemical composition Fe-15Cr-xAl-4Y2O3 with different Al contents x = 0.3 wt.%, 2.0 wt.% and 5.5 wt.% are prepared by mechanical alloying. The alloys are consolidated by high temperature rolling followed by heat treatment. To study the oxidation resistance the samples are isothermally aged in the air for 1 h, 4 h, 16 h and 64 h at 1200 °C. The oxidation kinetics, composition and formation mechanism of the oxide layers are analyzed. The weight gain of prepared steels is estimated. The kinetics of oxidation is studied on metallographic cross-sections of the exposed samples by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) analysis. The oxides on the surfaces are identified by X‑ray diffraction (XRD) analysis. The Al content significantly enhances the oxidation resistance of the alloy. For a sufficiently high Al content in the alloy a compact oxide layer of α‑Al2O3 on the surface is formed, which significantly suppresses further oxidation process.

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The Effect of Ultrafine-Grained Microstructure on Creep Behaviour of 9% Cr Steel

Cited by 17 publications

References 62 publications

Ageing Effects on Room-Temperature Tensile Properties and Fracture Behavior of Quenched and Tempered T92/TP316H Dissimilar Welded Joints with Ni-Based Weld Metal

Ageing Effects on Room-Temperature Tensile Properties and Fracture Behavior of Quenched and Tempered T92/TP316H Dissimilar Welded Joints with Ni-Based Weld Metal

The Effect of Electrolytic Hydrogenation on Mechanical Properties of T92 Steel Weldments under Different PWHT Conditions

The Influence of Aluminum Content on Oxidation Resistance of New-Generation ODS Alloy at 1200 °C

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