Electron backscattering diffraction analysis of secondary cleavage cracks in a reactor pressure vessel steel

Nohava, Jiří; Haušild, Petr; Karlı́k, Miroslav; Bompard, Philippe

doi:10.1016/s1044-5803(02)00360-1

Cited by 88 publications

(37 citation statements)

References 7 publications

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“…20) Figure 4(c) is {001} pole figure which shows the orientations of the lath within the prior austenite that corresponds to the area surround by the black solid square grid in the IPF map. According to references, 7,21,22) the concentrations near the ideal orientations based on the K-S orientation relationship are obvious, which confirms that the martensite and lower bainite in the T23 steel under investigation maintains the K-S orientation relationship. Though the orientation distribution is not discrete, it has a certain degree of scattering around the ideal orientations.…”

Section: Resultssupporting

confidence: 64%

Effect of Texture on the Cold Cracking in Weld Zone of T23 Steel

Jin

Lü

2015

ISIJ Int.

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Y-slit welded joints without preheating were used to prepare the cold cracks in T23 steel. Then the effect of texture on the cold cracking was studied from the views of macrotexture and microtexture. The results showed that the propagation path of the cold cracks was strongly affected by the macrotexture of the columnar grain structure after solidification. The fracture direction was changed at almost light-etched columnar grain but within each columnar grain an average fracture direction was maintained. The crack finally took the same initial direction before meeting another light-etched columnar grain. The strain distribution obtained by electron backscattered diffraction (EBSD) showed that different crystallography of the columnar grain induced large strain concentration, which led to the big angle transition of the main crack. In addition, transform texture, also named as microtexture in this study, had a large effect on the exact propagation paths of the cold cracks. The cold cracks propagated along lath boundaries which were almost parallel to {011}α plane.

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Section: Resultssupporting

confidence: 64%

Effect of Texture on the Cold Cracking in Weld Zone of T23 Steel

Jin

Lü

2015

ISIJ Int.

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“…Even though the bainitic packets are not always well defined, their size increases as both the austenitization temperature and time increase while, under the same austenitization conditions, it decreases as the austempering temperature decreases. According to [1,14], in fact, the bainitic packets develop inside the austenite grains and their size decreases as the prior austenitic grains decrease until, for very fine austenitic grains, each grain transforms into a packet. At low austempering temperatures the simultaneous presence of bainite and martensite packets, developing in the same austenite grains, magnifies the size reduction of the packet.…”

Section: Microstructurementioning

confidence: 99%

“…When a cleavage crack nucleates and propagates, the boundaries between the bainitic packets, or between the martensitic and bainitic packets can blunt the crack tip, stop crack propagation and/or change its propagating direction, thus increasing the energy needed for its growth [1,14]. The proportion of boundaries between the packet increases with the reduction in packet size, therefore the simultaneous presence of bainitic and martensitic packets that develop from austenite grains reduces their size and increases the impact toughness of the steel.…”

Section: Impact Testsmentioning

confidence: 99%

Effect of the Austempering Process on the Microstructure and Mechanical Properties of 27MnCrB5-2 Steel

Morri¹,

Ceschini²,

Pellizzari³

et al. 2017

Archives of Metallurgy and Materials

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The effect of austempering parameters on the microstructure and mechanical properties of 27MnCrB5-2 steel has been investigated by means of: dilatometric, microstructural and fractographic analyses; tensile and Charpy V-notch (CVN) impact tests at room temperature and a low temperature.Microstructural analyses showed that upper bainite developed at a higher austempering temperature, while a mixed bainiticmartensitic microstructure formed at lower temperatures, with a different amount of bainite and martensite and a different size of bainite sheaf depending on the temperature. Tensile tests highlighted superior yield and tensile strengths (≈30%) for the mixed microstructure, with respect to both fully bainitic and Q&T microstructures, with only a low reduction in elongation to failure (≈10%). Impact tests confirmed that mixed microstructures have higher impact properties, at both room temperature and a low temperature.

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“…Refs. [18][19][20][21][22]), it inherently assumes that the crack plane is perpendicular to the examined two-dimensional planar surface. A more precise identification of the crack planes requires three-dimensional analysis (by serial sectioning for example), however, this is beyond the scope of the present study.…”

Section: Experimental Methodsmentioning

confidence: 99%

Investigation of the effect of electrolytic hydrogen charging of X70 steel: II. Microstructural and crystallographic analyses of the formation of hydrogen induced cracks and blisters

Saleh

Hejazi

Gazder

et al. 2016

International Journal of Hydrogen Energy

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Pereloma, E. V. (2016). Investigation of the effect of electrolytic hydrogen charging of X70 steel: II. Microstructural and crystallographic analyses of the formation of hydrogen induced cracks and blisters. International Journal of Hydrogen Energy, 41 (28), 12424-12435. Investigation of the effect of electrolytic hydrogen charging of X70 steel: II. Microstructural and crystallographic analyses of the formation of hydrogen induced cracks and blisters AbstractHydrogen-induced cold cracking and blistering in hydrogen-charged X70 steel was found to be highly dependent on microstructure, with the banded ferrite-pearlite microstructure of hot rolled strip showing a higher susceptibility than other microstructures produced by different thermal-mechanical routes. Although crack initiation was particularly sensitive to microstructure, crack growth occurred largely parallel to the rolling plane, at least at a macroscopic level, for all of the microstructures investigated. The crack plane was associated with structural anisotropy arising from processing by rolling and was not found to be related to a preferred grain orientation. At a microstructural level, crack propagation was mostly transgranular and occurred dominantly along slip planes of the ferrite grains. Cracks were initiated at strong traps in the microstructure when the hydrogen and local stress concentrations reached critical levels for hydrogeninduced fracture. The main initiation sites were coarse inclusions, mainly oxides, and ferrite-pearlite interfaces. Keywords: X70 pipeline steel, electrolytic hydrogen charging, hydrogen-induced cold cracking (HICC), effect of microstructure, crystallography of cracking, effect of grain texture.

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Electron backscattering diffraction analysis of secondary cleavage cracks in a reactor pressure vessel steel

Cited by 88 publications

References 7 publications

Effect of Texture on the Cold Cracking in Weld Zone of T23 Steel

Effect of Texture on the Cold Cracking in Weld Zone of T23 Steel

Effect of the Austempering Process on the Microstructure and Mechanical Properties of 27MnCrB5-2 Steel

Investigation of the effect of electrolytic hydrogen charging of X70 steel: II. Microstructural and crystallographic analyses of the formation of hydrogen induced cracks and blisters

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