Phase quantification in low carbon Nb-Mo bearing steel by electron backscatter diffraction technique coupled with kernel average misorientation

Chen, Yu‐Wen; Tsai, Yu-Ting; Tung, Po‐Yen; Tsai, Shao-Pu; Chen, Chih-Yuan; Wang, Shing-Hao; Yang, Jer−Ren

doi:10.1016/j.matchar.2018.01.041

Cited by 71 publications

(8 citation statements)

References 32 publications

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“…Moreover, many martensite and austenite (M/A) islands (marked by red arrows in Figure 2 e) were observed at the BF boundaries. When the initial cooling temperature decreased to 770 °C, the longer relaxation process led to an increase in the volume fraction of PF (38%), and the pearlite phase was observed [ 22 , 23 ], as shown in Figure 2 c,f. The higher volume fraction of PF promotes the stability of the austenite, and the formation rich and poor carbon zones in austenite provides conditions for the formation of pearlite.…”

Section: Resultsmentioning

confidence: 99%

Enhancing Strain Capacity by the Introduction of Pearlite in Bainite and Polygonal Ferrite Dual-Phase Pipeline Steel

Ren²,

Shi

et al. 2021

Materials

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In this study the strain capacity and work-hardening behavior of bainite (B), bainite + polygonal ferrite (B + PF), and bainite + polygonal ferrite + pearlite (B + PF + P) microstructures are compared. The work hardening exponent (n), instantaneous work hardening value (ni), and differential Crussard-Jaoul (DC-J) analysis were used to analyze the deformation behavior. The best comprehensive mechanical properties were obtained by the introduction of the pearlite phase in B + PF dualphase with the tensile strength of 586 MPa and total elongation of 31.0%. The additional pearlite phase adjusted the strain distribution, which increased the initial work hardening exponent and then maintained the entire plastic deformation at a high level, thus delayed necking. The introduction of pearlite reduced the risk of micro-void initiation combined with the high frequency of high angle grain boundaries (HAGBs) in triple-phase steel, which led to a low crack propagation rate.

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Section: Resultsmentioning

confidence: 99%

Enhancing Strain Capacity by the Introduction of Pearlite in Bainite and Polygonal Ferrite Dual-Phase Pipeline Steel

Ren²,

Shi

et al. 2021

Materials

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“…To study the distribution of deformation at the cutting edge of the punched sample, the kernel average misorientation (KAM), which calculates the average misorientation between the chosen pixel and its neighbors [10], was applied to analyze the local grain misorientation for studying the distribution of geometrically necessary dislocations (GNDs). During the KAM analysis of this study, the first neighbor was chosen to define the kernel size of calculation, and the maximum misorientation (or exclusion angle) was selected as 5 • to ensure the intra-substructure analysis instead of inter-substructure analysis.…”

Section: Microstructure Analysismentioning

confidence: 99%

Mechanism of Blunt Punching Tools’ Influence on Deformation and Residual Stress Distribution

Wei

Fang

Wang

et al. 2021

Metals

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Punching is the main manufacturing process with high efficiency and machining accuracy used to produce the iron cores of motors. However, it usually introduces residual stress at the cutting edge and affects the magnetic properties of the iron core. Further studies show that the tensile residual stress (TRS) has a negligible effect on the magnetic properties, compared with the compressive stress. The blunt punch tools cause local TRS and the formation of local large plastic deformation (PD) at the cutting edge as the cost. The PD has a more serious effect on the magnetic properties of materials than TRS. Therefore, this study mainly focused on local deformation distribution and the associated microstructure evolution using EBSD (Electron Backscatter Diffraction) and finite element analysis; and the formation mechanism of tensile residual stress during the punching process at the cutting edge of a non-oriented silicon steel after punching with blunt tools, by using nanoindentation and a numerical simulation. The experimental results showed the existence of a specific bending area, a highly deformed area and a large burr at the cutting edge. These direct observations were confirmed with those obtained by the simulation model. Furthermore, the tensile residual stress on the surface was verified through nanoindentation tests and by a numerical simulation. The results indicate also that the formation of a tensile residual stress zone depends especially on the bending area formed during punching with blunt tools.

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“…Also, coincident site lattice (CSL) boundaries with HABs with low stored energy due to good atomic fit between neighboring crystals can act as crack arrester. KAM map indicates the local plastic strain variations measured between the central point and its nearest neighbors when the misorientation between them exceeds 5° in eliminating the effect of grain boundaries [44,45]. The high KAM angles appear cumulative build-up of misorientation inside the grain or the presence of sub-grain boundaries, Figures 6b and 7b.…”

Section: Crystallographic Texturementioning

confidence: 99%

Effect of Textures and Microstructures on the Occurrence of Delamination during and after Fracture Toughness Tests of API X80 Steel Plates

Conde¹,

Pinto²,

Masoumi³

et al. 2020

Strength of Materials

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The API 5 L X80 is a high strength microalloyed steel, widely used in the gas and oil industry to fabricate pipelines. This steel presents a combination of elevated strength and toughness. In the present investigation, the microstructural features, fracture toughness and delamination occurrence of two X80 grade steel plates with different processing routes and chemical composition were studied. The first steel depicted a homogenous bainitic matrix and the second steel exhibited a banded microstructure composed of elongated ferrite grains, with macrosegregation in the mid-plane of the plates. Fracture toughness tests were conducted for both steels on 7-mm and 15-mm thick samples. The orientation distribution functions analysis revealed crystallographic intensity distribution of the austenite to ferrite transformation texture, especially the alpha-fiber (< 011 > || rolling direction) which explained the anisotropy and delamination occurrences. Both processed plates of steel presented the alpha-fiber due to hot-rolling of plates. Delaminations occurrences were further investigated and attributed to a strong {100} <011> orientation presence despite microstructure homogeneity. A schematic model was proposed, showing the source of delamination and the reason for the lowest toughness for 45° to the rolling direction.

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Phase quantification in low carbon Nb-Mo bearing steel by electron backscatter diffraction technique coupled with kernel average misorientation

Cited by 71 publications

References 32 publications

Enhancing Strain Capacity by the Introduction of Pearlite in Bainite and Polygonal Ferrite Dual-Phase Pipeline Steel

Enhancing Strain Capacity by the Introduction of Pearlite in Bainite and Polygonal Ferrite Dual-Phase Pipeline Steel

Mechanism of Blunt Punching Tools’ Influence on Deformation and Residual Stress Distribution

Effect of Textures and Microstructures on the Occurrence of Delamination during and after Fracture Toughness Tests of API X80 Steel Plates

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