Effect of high temperature deformation on the microstructure, mechanical properties and hydrogen embrittlement of 2.25Cr–1Mo-0.25 V steel

Wang, Yafei; Cheng, Guangxu; Qin, Mu; Li, Qing; Zhang, Zaoxiao; Chen, Kang; Li, Yun; Hu, Haijun; Wu, Wei; Zhang, Jianxiao

doi:10.1016/j.ijhydene.2017.07.237

Cited by 31 publications

(12 citation statements)

References 67 publications

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“…This method has been previously used for the HE tests of various materials including the Cr–Mo steel [ 20 ]. Additionally, the immersion charging method possesses higher efficiency and more simplicity in comparison with the other hydrogen charging methods [ 21 ]. In this work, the specimens were first fatigue pre-cracked to achieve a/W ≈ 0.5 (a is the total length of the notch starter plus the fatigue crack, and W is the width of the specimen), where the maximum peak force was 4 kN, and the stress ratio (minimum peak force/maximum peak force) was set to 0.1.…”

Section: Methodsmentioning

confidence: 99%

Experimental Investigation of the Effect of Hydrogen on Fracture Toughness of 2.25Cr-1Mo-0.25V Steel and Welds after Annealing

Song

Chai

et al. 2018

Materials

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Hydrogen embrittlement (HE) is a critical issue that hinders the reliability of hydrogenation reactors. Hence, it is of great significance to investigate the effect of hydrogen on fracture toughness of 2.25Cr-1Mo-0.25V steel and weld. In this work, the fracture behavior of 2.25Cr-1Mo-0.25V steel and welds was studied by three-point bending tests under hydrogen-free and hydrogen-charged conditions. The immersion charging method was employed to pre-charge hydrogen inside specimen and the fracture toughness of these joints was evaluated quantitatively. The microstructure and grain size of the specimens were observed by scanning electron microscopy (SEM) and by metallurgical microscopy to investigate the HE mechanisms. It was found that fracture toughness for both the base metal (BM) and the weld zone (WZ) significantly decreased under hydrogen-charged conditions due to the coexistence of the hydrogen-enhanced decohesion (HEDE) and hydrogen-enhanced localized plasticity (HELP) mechanisms. Moreover, the formation and growth of primary voids were observed in the BM, leading to a superior fracture toughness. In addition, the BM compared to the WZ shows superior resistance to HE because the finer grain size in the BM leads to a larger grain boundary area, thus distributing more of the diffusive hydrogen trapped in the grain boundary and reducing the hydrogen content.

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Section: Methodsmentioning

confidence: 99%

Experimental Investigation of the Effect of Hydrogen on Fracture Toughness of 2.25Cr-1Mo-0.25V Steel and Welds after Annealing

Song

Chai

et al. 2018

Materials

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“…The NH 4 SCN immersion charging method has been proved to be simpler and more efficient compared to other hydrogen charging methods, such as the electrochemical charging method [ 11 ]. Moreover, it has also been previously employed for HE studies of several alloys involving the high strength Cr-Mo steels [ 11 , 12 ]. In the present investigation, specimens were initially pre-cracked under sinusoidal cyclic load to gain a 3 mm fatigue crack, wherein the maximum and minimum peak forces were 4 kN and 0.4 kN, respectively [ 13 ].…”

Section: Methodsmentioning

confidence: 99%

Investigation of the Influence of Pre-Charged Hydrogen on Fracture Toughness of As-Received 2.25Cr1Mo0.25V Steel and Weld

et al. 2018

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Fracture failure caused by hydrogen embrittlement (HE) is a major concern for the system reliability and safety of hydrogen storage vessels, which are generally made of 2.25Cr1Mo0.25V steel. Thus, study of the influence of pre-charged hydrogen on fracture toughness of as-received 2.25Cr1Mo0.25V steel and weld is of significant importance. In the current work, the influence of hydrogen on fracture toughness of as-received 2.25Cr1Mo0.25V steel and weld was systematically studied. Base metal (BM) and weld metal (WM) specimens under both hydrogen-free and hydrogen-charged conditions were tested using three-point bending tests. Hydrogen was pre-charged inside specimens by the immersion charging method. The J-integral values were calculated for quantitatively evaluating the fracture toughness. In order to investigate the HE mechanisms, optical microscopy (OM) and scanning electron microscopy (SEM) were used to characterize the microstructure of BM and WM specimens. The results revealed that the presence of pre-charged hydrogen caused a significant decrease of the fracture toughness for both BM and WM specimens. Moreover, the pre-charged hydrogen led to a remarkable transition of fracture mode from ductile to brittle pattern in 2.25Cr1Mo0.25V steel.

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“…The further propagation of fatigue cracks will cause serious failure of equipment once the crack size exceeds the critical size. In recent years, a large number of studies focused on the microstructures and mechanical properties [ 3 , 4 , 5 ], reheat cracking sensitivity [ 6 , 7 ], creep behavior [ 8 ] and hydrogen-induced damage [ 4 , 9 ] of 2.25Cr1Mo0.25V steel; however, the study of fatigue crack growth (FCG) behavior is limited. For instance, Peral et al [ 10 ] investigated the combined effects of the pre-charged hydrogen and loading frequency on FCG behavior of 2.25Cr1Mo and 2.25Cr1Mo0.25V steels.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Fatigue Crack Growth Behavior of the 2.25Cr1Mo0.25V Steel Welded Joint Used in Hydrogenation Reactors

2021

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In this work, the fatigue crack growth (FCG) behavior and fatigue damage mechanism of the 2.25Cr1Mo0.25V steel welded joint used in hydrogenation reactors were investigated. The multi-pass welding was carried out to manufacture the welded joint using the combined shielded metal arc welding (SMAW) and submerged automatic arc welding (SAAW) processes. The FCG behavior of different zones in the welded joint, including the base metal (BM), the heat-affected zone (HAZ) and the weld metal (WM), were studied by compact tension tests. Moreover, the acoustic emission (AE) technique was used to monitor AE signals generated from FCG process for further understanding FCG behavior and fatigue mechanisms. Additionally, the microstructures and fracture surfaces of different specimens were observed by optical microscopy (OM) and scanning electron microscopy (SEM). The results revealed that the microstructure of BM is fine granular bainite, while the WM shows coarser bainite grains. The HAZ exhibits the most significant inhomogeneity with large dispersion of grain size. FCG results showed that the HAZ exhibits much higher fatigue crack growth rate (FCGR) at low ΔK values, while the BM shows the most superior fatigue resistance. The AE technique is successful in monitoring and identifying damage evolutions during the FCG process. Moreover, an enhanced AE activity is observed in FCG of the WM specimen, which is attributed to the combined influence of the formation of numerous secondary cracks and coarse-grained microstructures.

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Effect of high temperature deformation on the microstructure, mechanical properties and hydrogen embrittlement of 2.25Cr–1Mo-0.25 V steel

Cited by 31 publications

References 67 publications

Experimental Investigation of the Effect of Hydrogen on Fracture Toughness of 2.25Cr-1Mo-0.25V Steel and Welds after Annealing

Experimental Investigation of the Effect of Hydrogen on Fracture Toughness of 2.25Cr-1Mo-0.25V Steel and Welds after Annealing

Investigation of the Influence of Pre-Charged Hydrogen on Fracture Toughness of As-Received 2.25Cr1Mo0.25V Steel and Weld

Experimental Investigation of Fatigue Crack Growth Behavior of the 2.25Cr1Mo0.25V Steel Welded Joint Used in Hydrogenation Reactors

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