Probing True Microstructure-Hardening Relationship in Simulated Heat Affected Zone of P91B Steels

Ахтар, Модассир; Khajuria, Akhil

doi:10.1007/s13632-019-00573-w

Cited by 24 publications

(21 citation statements)

References 21 publications

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Section: Resultsmentioning

confidence: 99%

“…However, the method of revelation of true microstructure of Gleeble simulated samples was already reported in previous work. 10,19 Results and discussions…”

Section: Microstructure Characterizationmentioning

confidence: 99%

“…Since the creep behavior of subzones of HAZ in P91 steel is mainly dependent upon microstructural manifestations after welding and subsequent PWHT, it was essential to ensure that true microstructural replica after Gleeble HAZ simulation was produced as reported previously for different set of samples. 19 By intercept method, average prior austenite (PAG) size with standard deviation was measured as 18 6 8.9, 36 6 9.9, 13 6 6.1, and 16 6 3.4 mm for PM, CGHAZ, FGHAZ, and ICHAZ, respectively. While same was measured as 28 6 9.7, 26 6 6.5, 24 6 3.6, and 28 6 2.8 mm for B-PM, B-CGHAZ, B-FGHAZ, and B-ICHAZ, respectively.…”

Section: Morphological Characteristics Of Evolved Microstructurementioning

confidence: 99%

“…12,17 However, microstructural as well as creep mechanisms that mitigate type IV failure on additions of small concentration of boron to P91 steel are still being researched. 17–25 The gravity of this issue has been summarized in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

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A novel approach to envisage effects of boron in P91 steels through Gleeble weld-HAZ simulation and impression-creep

Khajuria

Ахтар

Bedi

2021

The Journal of Strain Analysis for Engineering Design

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This paper induced a novel methodology for the characterization of creep behavior of weld heat-affected zone (HAZ) for boron-free P91 (PM) and boron modified P91B (B-PM) steels. Gleeble-3800 thermo-mechanical simulator replicated specimens, representing coarse-grain HAZ (CGHAZ), fine-grained HAZ (FGHAZ), and inter-critical HAZ (ICHAZ). Short-term impression creep tests were conducted at 625°C/270-410MPa on PM/B-PM and their simulated HAZs after being subjected to post-weld heat treatment (PWHT) of 760°C/3 h. Microstructural characterization and local strain analyses were accomplished by electron back-scattered diffraction. Simulated microstructures of P91B-FG/ICHAZ after PWHT exhibited lath martensitic structure and large prior-austenite grain size as regards P91-FG/ICHAZ, correspondingly. Average values of local microstructural strain from local average misorientation were relatively high in B-PM and P91B-ICHAZ than PM and P91-ICHAZ, respectively. Similar observations were found for P91-CG/FGHAZ with their counterparts. Stress dependent steady-state creep-rate (SSCR) followed power-law for all specimens except PM. The minimum and maximum ranges of SSCR for P91B specimens were observed to be in a narrower range than P91 specimens. The value of stress exponent for all specimens was evaluated, and corresponding mechanisms were discussed. The analyses of microstructures and corresponding impression creep behavior of P91/P91B samples suggested that modification of 100 ppm boron to P91 steel improved creep-rupture ductility that delayed type IV failure at outer HAZ of P91 steel weldments.

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Section: Resultsmentioning

confidence: 99%

“…However, the method of revelation of true microstructure of Gleeble simulated samples was already reported in previous work. 10,19 Results and discussions…”

Section: Microstructure Characterizationmentioning

confidence: 99%

Section: Morphological Characteristics Of Evolved Microstructurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A novel approach to envisage effects of boron in P91 steels through Gleeble weld-HAZ simulation and impression-creep

Khajuria

Ахтар

Bedi

2021

The Journal of Strain Analysis for Engineering Design

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“…[17] Many studies have been conducted to investigate the microstructure, mechanical properties and heat treatment process of Cr-Mo steel. [18][19][20][21][22] In this study, the size effect of 18CrNiMo7-6 steel was investigated by rotating bending fatigue tests. The fracture surfaces of the specimens after the fatigue tests were observed by scanning electron microscopy (SEM), and the effects of the surface condition, stress gradient, residual stress, and crack propagation on the size effect and fatigue performance are discussed.…”

Section: Introductionmentioning

confidence: 99%

Size Effect on the Fatigue Performance of 18CrNiMo7‐6 Alloy Steel

Wang

Gao

Zhang

et al. 2021

steel research int.

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The size effect on the fatigue performance of 18CrNiMo7-6 alloy steel is investigated. From rotating bending fatigue tests at room temperature, the relationship between the stress amplitude and the number of cycles of specimens with different diameters is obtained. The surface topography, residual stress, and fracture surface of the specimen are measured. The results show that the fatigue strength increases with increasing diameter of the specimen. The fracture of the small specimens tends to be brittle fracture, whereas the fracture of the large specimens is inclined to be ductile fracture. The effects of the surface condition, relative stress gradient (RSG), residual stress, and fatigue crack propagation life on the fatigue performance of the alloy are discussed. The reasons for the size effect are interpreted in terms of the change in the RSG caused by residual stress, the trend of the RSG significantly changes with changing specimen size under different stress levels. The crack propagation life of the large specimens is longer than those of the small specimens.

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The Synergistic Effects of Boron and Impression Creep Testing during Paced Controlling of Temperature for P91 Steels

Ахтар

Khajuria

2023

Adv Eng Mater

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This article induces the quadruple knowledge on effects of 100 ppm (P91B) and 22 ppm (P91) boron in as‐received 9Cr steels in normalized and tempered conditions (NT) and impression crept conditions (ICC). Herein, impression creep testing is improved through paced temperature to fast evaluate creep performance. P91B performs the utmost by advancing activation energy and 30% better creep life, leading to same targeted creep life to 574 °C than P91 at 550 °C. Further, it incisively discusses variations in microstructure, precipitate size, geometrically necessary dislocations (GNDs), pseudo‐rocking curve, grain size (GS), several types of grain boundaries (GBs), effective GB energy, and elastic stiffness. Novel phenomenological mechanisms like GB hardening/softening; antithetical mechanisms; boron‐dependent mosaicity; grain refinement/fragmentation/coarsening/homogenization; interaction among various types of GBs, triggering re/degeneration of dislocations and Σ boundaries as Σ reactions; super‐continuous and geometric dynamic recrystallizations; enhanced creep immunity of like‐oriented GBs than unlike oriented GBs; primary/secondary recrystallization; specialness; boron/NT/ICC‐dependent stiffness; high stiffness is dependent on low GNDs and big GS, and vice versa are observed. The synergistic effects of [100 ppm boron in NT/ICC] and ICC in manifestation of 22/100 ppm boron are ascertained. However, dependency [proportionally and antithetically] and independency of GB character on creep‐microstructural reciprocity discourse and converse into the mathematical relationship.

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Probing True Microstructure-Hardening Relationship in Simulated Heat Affected Zone of P91B Steels

Cited by 24 publications

References 21 publications

A novel approach to envisage effects of boron in P91 steels through Gleeble weld-HAZ simulation and impression-creep

A novel approach to envisage effects of boron in P91 steels through Gleeble weld-HAZ simulation and impression-creep

Size Effect on the Fatigue Performance of 18CrNiMo7‐6 Alloy Steel

The Synergistic Effects of Boron and Impression Creep Testing during Paced Controlling of Temperature for P91 Steels

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