Effect of temper and hydrogen embrittlement on mechanical properties of 2,25Cr–1Mo steel grades – Application to Minimum Pressurizing Temperature (MPT) issues. Part II: Vintage reactors &amp; MPT determination

Pillot, Sylvain; Chauvy, Cédric; Corre, Stéphanie; Coudreuse, L.; Gingell, Andrew; Héritier, Déborah; Toussaint, P.

doi:10.1016/j.ijpvp.2013.04.018

Cited by 7 publications

(3 citation statements)

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“…In addition, it was also indicated that the electrochemical pre-charging method seems to be sufficiently conservative with respect to gaseous hydrogen exposure [ 9 ]. Pillot et al studied the effect of hydrogen on mechanical properties of 2.25Cr–1Mo steel grades and showed that, with increasing hydrogen content, the charpy fracture toughness of 2.25Cr–1Mo decreased [ 10 , 11 ].…”

Section: Introductionmentioning

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: Introductionmentioning

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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“…This promotes the formation of intergranular pores and weakens the cohesion of neighboring grains. As a result, the fracture of the structural elements is facilitated due to creep (especially in a hydrogenating medium [30][31][32]) and thermal cycling (in particular, due to frequent shutdowns of the technological process) [14,33,34].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Mechanical Properties of Welded Joint Metal from TPP Steam Piping after Its Operational Degradation and Hydrogenation

Hutsaylyuk,

Student,

Maruschak

et al. 2023

Materials

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In this paper, the mechanical properties of various zones of the welded joints of a heat-resistant steel 15Kh1M1F in different states (in the initial state, after an operation on the main steam piping of a thermal power plant (TPP) for 23 years) were determined, and the fracture surfaces were analyzed using scanning electron microscopy (SEM) images. The effect of hydrogen electrolytic charging on mechanical behavior and fracture mechanism was also studied. The long-term operation of welds resulted in a higher degradation degree of the weld metal compared to the base one, indicated by the deterioration of mechanical properties: decrease in hardness, strength characteristics, and reduction in area, which was accompanied by an atypical increase in elongation at fracture. All studied zones of the operated welded joints were characterized by higher hydrogen content, 2.5–3 times higher than that in the initial state. Additional hydrogen charging of the weld joint metal led to a decrease in the strength and ductility characteristics, more significantly for the operated weld compared with the non-operated one. This justified the possibility of using short-term tests of hydrogenated WM in the air to assess the degree of its damage during operation on a steam piping.

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“…This kind of TE is revisable and can be eliminated by applying a de-embrittlement at 600–650 °C heat treatment [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

Study on Temper Embrittlement and Hydrogen Embrittlement of a Hydrogenation Reactor by Small Punch Test

et al. 2017

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The study on temper embrittlement and hydrogen embrittlement of a test block from a 3Cr1Mo1/4V hydrogenation reactor after ten years of service was carried out by small punch test (SPT) at different temperatures. The SPT fracture energy Esp (derived from integrating the load-displacement curve) divided by the maximum load (Fm) of SPT was used to fit the Esp/Fm versus-temperature curve to determine the energy transition temperature (Tsp) which corresponded to the ductile-brittle transition temperature of the Charpy impact test. The results indicated that the ratio of Esp/Fm could better represent the energy of transition in SPT compared with Esp. The ductile-to-brittle transition temperature of the four different types of materials was measured using the hydrogen charging test by SPT. These four types of materials included the base metal and the weld metal in the as-received state, and the base metal and the weld metal in the de-embrittled state. The results showed that there was a degree of temper embrittlement in the base metal and the weld metal after ten years of service at 390 °C. The specimens became slightly more brittle but this was not obvious after hydrogen charging. Because the toughness of the material of the hydrogenation reactor was very good, the flat samples of SPT could not characterize the energy transition temperature within the liquid nitrogen temperature. Additionally, there was no synergetic effect of temper embrittlement and hydrogen embrittlement found in 3Cr1Mo1/4V steel.

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Effect of temper and hydrogen embrittlement on mechanical properties of 2,25Cr–1Mo steel grades – Application to Minimum Pressurizing Temperature (MPT) issues. Part II: Vintage reactors & MPT determination

Cited by 7 publications

References 0 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

Analysis of Mechanical Properties of Welded Joint Metal from TPP Steam Piping after Its Operational Degradation and Hydrogenation

Study on Temper Embrittlement and Hydrogen Embrittlement of a Hydrogenation Reactor by Small Punch Test

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