Effect of hydrogen on the properties and fracture characteristics of TRIP 800 steels

Sojka, Jaroslav; Vodárek, Vlastimil; Schindler, Ivo; Ly, Céline; Jérôme, M.; Váňová, Petra; Ruscassier, N.; Wenglorzová, Andrea

doi:10.1016/j.corsci.2011.04.015

Cited by 57 publications

(29 citation statements)

References 26 publications

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“…Thus the hydrogen absorption may contribute to the local toughness deterioration and final failure. Embrittlement of metallic materials including creep-resistant steels by the absorbed hydrogen is a wellknown phenomenon, commonly denoted as hydrogen embrittlement (HE) [6][7][8]. In the case of cooling-down of the power plants below 150 °C after their shutdowns, the hydrogen dissolved in steels may lead to the low threshold stress intensity for crack propagation at ambient temperature under tensile stress conditions.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Thermal Exposure and Hydrogen Charging on the Notch Tensile Properties and Fracture Behaviour of Dissimilar T91/TP316H Weldments

Blach

Falat

2013

High Temperature Materials and Processes

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The effects of ageing and hydrogen charging on the notch tensile properties and fracture behaviour of individual heat-affected zones (HAZ) and Ni-based weld metal (Ni WM) of T91/TP316H weldments were investigated. After the post-weld heat treatment at 750 °C for 1 h the weldments were annealed at 600 °C for 1000 h and 5000 h, respectively. All heat-treated states were studied in condition without as well as with hydrogen charging. Thermal expositions led to additional precipitation and microstructure coarsening but their influence on tensile strength was insignificant. In contrast, remarkable plasticity decrease and the fracture mode transition from ductile dimple tearing to transgranular cleavage were observed. The combined effects of thermal exposure and hydrogen charging were more complex. Whereas the regions of Ni WM and TP316H HAZ did not show any significant change in strength, the hydrogen effect caused the strength increase in T91 HAZ. Although the hydrogen embrittling effects were clearly manifested by decreasing plasticity, their significance was getting smaller with increasing annealing duration. The fracture behaviour of thermally exposed and hydrogen charged regions exhibited mixed fracture modes including transgranular cleavage, intergranular dimple fracture and intergranular decohesion.

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Section: Introductionmentioning

confidence: 99%

The Influence of Thermal Exposure and Hydrogen Charging on the Notch Tensile Properties and Fracture Behaviour of Dissimilar T91/TP316H Weldments

Blach

Falat

2013

High Temperature Materials and Processes

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“…According to specific morphological terminology for hydrogen embrittlement fracture features, described e.g. in [52][53][54], the typical "fish-eyes" and "crows-feet" marks are clearly distinguishable on fracture surfaces of T24 HAZ and T92 HAZ, respectively. It can reasonably be assumed that the aged HAZ regions contain a higher concentration of hydrogen than base mate- rials under the same cathodic charging conditions.…”

Section: Fracture Behaviourmentioning

confidence: 99%

Hydrogen pre-charging effects on the notch tensile properties and fracture behaviour of heat-affected zones of thermally aged welds between T24 and T92 creep-resistant steels

Falat¹,

Čiripová²,

Homolová³

et al. 2016

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The effects of thermal exposure at 600• C and subsequent electrolytic hydrogen charging at ambient temperature were studied in terms of their influence on notch-tensile properties and fracture behaviour of individual heat-affected zones (HAZ) of Ni-based transition weldments between T24 and T92 creep-resistant steels. The experimental welded joints were prepared by gas tungsten arc welding using "Inconel-type" filler metal Nirod 600. Post-weld heat treatment (PWHT) was carried out at 720• C for 2 h, followed by passive cooling within tempering furnace. Subsequent long-term ageing of two series of prepared T24/T92 dissimilar welds at 600• C for 1000 and 5000 h, respectively, led to gradual changes in both T24 and T92 HAZ microstructures, which were mainly related to their additional tempering accompanied by the coarsening of original precipitates as well as newly-formed secondary phases. The observed thermally-induced microstructural changes together with subsequently applied hydrogen charging effects resulted in complex variations in tensile properties and fracture behaviour of individual HAZ regions related to the pre-existing differences in their initial tempering grade due to the used PWHT procedure. K e y w o r d s : creep-resistant steels, dissimilar welding, isothermal ageing, hydrogen embrittlement, mechanical properties, fracture mechanisms

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“…For instance, martensitic steels [1,2], dual-phase steels [3], transformation-induced plasticity (TRIP) steels [4,5], and twinning-induced plasticity (TWIP) steels [6][7][8] have been reported to show hydrogen-assisted cracking and its associated embrittlement.…”

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confidence: 99%

Positive and negative effects of hydrogen on tensile behavior in polycrystalline Fe–30Mn–(6 −x)Si–xAl austenitic alloys

et al. 2015

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We investigated the tensile properties of Fe-30Mn-(6 À x)Si-xAl (in wt.%, x = 0, 2, 3, 6) austenitic alloys precharged with hydrogen gas at 10 MPa. The Fe-30Mn-6Al alloy showed hydrogen-improved elongation through enhancement of work hardening capacity in the plastic instability condition, although the other alloys did not. This improvement in elongation is considered to be a result of a reduction in stacking fault energy because deformation twinning appeared only in the hydrogen-precharged condition.Hydrogen is recognized as a negative solute element that deteriorates mechanical properties of advanced high strength steels. For instance, martensitic steels [1,2], dual-phase steels [3], transformation-induced plasticity (TRIP) steels [4,5], and twinning-induced plasticity (TWIP) steels [6][7][8] have been reported to show hydrogen-assisted cracking and its associated embrittlement.Although hydrogen negatively affects mechanical properties in most cases, embrittlement is caused by various factors: enhancement of dislocation motion [9], reduction in surface energy and increase in interface energy [10], promotion of vacancy formation [11], reduction in stacking fault energy, etc. [12]. When hydrogen embrittlement occurs, all of these factors are noticed only as negative effects.However, a reduction in stacking fault energy of austenitic steels is generally known to enhance work hardening [13,14], which improves tensile elongation [13]. For instance, TWIP steels were recently designed by decreasing stacking fault energy to promote deformation twinning in austenitic steels [15,16], which have drawn attention as a new class of high strength steels with excellent workability. Therefore, the hydrogen effect decreasing the stacking fault energy is expected to enhance work hardening through promotion of deformation twinning or suppression of dislocation cross-slip. Furthermore, hydrogen would segregate to partials and stacking faults due to strain aging and Suzuki effect, enhancing the effect of hydrogen on work hardening. Accordingly, the tensile elongation is also expected to be improved by hydrogen.Astafurova et al. [17] reported that hydrogen could promote deformation twinning in a single-crystalline Hadfield steel, and accordingly, elongation and strength were improved. However, a similar strategy for positively utilizing hydrogen in polycrystalline austenitic steels has never been reported. In this paper, we report an example of positive effect of hydrogen on tensile elongation in terms of a reduction in stacking fault energy.Fe-30Mn-(6 À x)Si-xAl (x = 0, 2, 3, 6) austenitic alloys were prepared using vacuum induction melting with high-purity metals. Chemical compositions of the Fe-30Mn-(6 À x)Si-xAl (x = 0, 2, 3, 6) alloys are listed in Table 1. The Fe-30Mn-6Si alloy is known to be a shape memory alloy with deformation-induced e-martensitic transformation [18,19]. In this study, Si was substituted by Al to increase stacking fault energy [15]. The stacking fault energies of the Fe-30Mn-6Si, Fe-30Mn-4Si-2Al, Fe-30Mn-3S...

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Effect of hydrogen on the properties and fracture characteristics of TRIP 800 steels

Cited by 57 publications

References 26 publications

The Influence of Thermal Exposure and Hydrogen Charging on the Notch Tensile Properties and Fracture Behaviour of Dissimilar T91/TP316H Weldments

The Influence of Thermal Exposure and Hydrogen Charging on the Notch Tensile Properties and Fracture Behaviour of Dissimilar T91/TP316H Weldments

Hydrogen pre-charging effects on the notch tensile properties and fracture behaviour of heat-affected zones of thermally aged welds between T24 and T92 creep-resistant steels

Positive and negative effects of hydrogen on tensile behavior in polycrystalline Fe–30Mn–(6 −x)Si–xAl austenitic alloys

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