Influence of hydrogen on softened heat-affected zones during in-situ slow strain rate testing in advanced high-strength steel welds

Park, Hanji; Park, Cheol-Ho; Lee, Junghoon; Kang, Ning; Liu, Stephen V.

doi:10.1016/j.corsci.2020.109229

Cited by 18 publications

(11 citation statements)

References 51 publications

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“…This strain explains the dimple fracture observed in the HSC fractography (Figure 7b). To explain the effect of hydrogen on this phenomenon, a hydrogen-enhanced strain-induced void (HESIV) mechanism was suggested, which was observed in our previous study [17]. According to the HESIV theory, voids can be easily formed by the hydrogen at the intersections of hydrogen trapping sites such as carbide interfaces, lath boundaries, and dislocations [17,36,37].…”

Section: Effect Of Type-ii Boundary Microstructure On the Hsc Behaviour Of The Wjsmentioning

confidence: 95%

“…After polishing the gauge section up to #2400 grit SiC paper, hydrogen was electrochemically pre-charged with a current density of 50 A/m 2 for 48 h in 3% NaCl and 0.3% NH 4 SCN aqueous solution containing As 2 O 3 (0.5 g L −1 ) to prevent the recombination of hydrogen atoms at the specimen surface. On the basis of our previous study, we assumed that the time required for hydrogen to diffuse through the ferrite phase to the centre of the tensile specimen with a thickness of 2 mm would be approximately 5 h [17]. Therefore, considering the difference between the hydrogen charging conditions used in this study and those used in the previous study, pre-charging for 48 h was determined to be sufficient to reach the equilibrium distribution up to the ferrite phase and the interface of the ferrite and austenite phases within the gauge length.…”

Section: Mechanical Testing and In-situ Ssrtmentioning

confidence: 99%

“…The SSRT was conducted at a cross-head speed of 2.5 × 10 −5 mm s −1 (nominal strain rate = 10 −6 s −1 ). The schematic of the in situ SSRT is shown in the authors' previous study [17].…”

Section: Mechanical Testing and In-situ Ssrtmentioning

confidence: 99%

“…To evaluate the HSC sensitivity of the WJs, their ΔRoAs were measured instead of quantifying the decrease in their displacement. This is because the transverse WJs had a non-uniform microstructure distribution within the gauge section [17]. The ΔRoAs of the WJs with the DF and AF were almost the same (~65%), indicating that hydrogen caused rapid fracturing immediately after reaching the ultimate tensile stress (UTS) with little plastic deformation.…”

Section: Tensile Behaviour Of the Transverse Wjs With Respect To Hydrogen Chargingmentioning

confidence: 99%

“…Low carbon steel normally has good weldability, and the welding of high strength steels produces a softened zone where the strain is concentrated making it vulnerable to HSC initiation. Furthermore, the welding microstructures have high hardness, such as MA constituent and martensite, accelerate hydrogen embrittlement [16][17][18]. In the case of dissimilar-welded joints in DSS and carbon steel, the ferrite phase fraction is increased in the heat affected zone (HAZ) of the DSS and the softened HAZ of high-strength carbon steels.…”

Section: Introductionmentioning

confidence: 99%

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Hydrogen Stress Cracking Behaviour in Dissimilar Welded Joints of Duplex Stainless Steel and Carbon Steel

Park

Moon

et al. 2021

Metals

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As the need for duplex stainless steel (DSS) increases, it is necessary to evaluate hydrogen stress cracking (HSC) in dissimilar welded joints (WJs) of DSS and carbon steel. This study aims to investigate the effect of the weld microstructure on the HSC behaviour of dissimilar gas-tungsten arc welds of DSS and carbon steel. In situ slow-strain rate testing (SSRT) with hydrogen charging was conducted for transverse WJs, which fractured in the softened heat-affected zone of the carbon steel under hydrogen-free conditions. However, HSC occurred at the martensite band and the interface of the austenite and martensite bands in the type-II boundary. The band acted as an HSC initiation site because of the presence of a large amount of trapped hydrogen and a high strain concentration during the SSRT with hydrogen charging. Even though some weld microstructures such as the austenite and martensite bands in type-II boundaries were harmless under normal hydrogen-free conditions, they had a negative effect in a hydrogen atmosphere, resulting in the premature rupture of the weld. Eventually, a premature fracture occurred during the in situ SSRT in the type-II boundary because of the hydrogen-enhanced strain-induced void (HESIV) and hydrogen-enhanced localised plasticity (HELP) mechanisms.

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Section: Effect Of Type-ii Boundary Microstructure On the Hsc Behaviour Of The Wjsmentioning

confidence: 95%

Section: Mechanical Testing and In-situ Ssrtmentioning

confidence: 99%

Section: Mechanical Testing and In-situ Ssrtmentioning

confidence: 99%

Section: Tensile Behaviour Of the Transverse Wjs With Respect To Hydrogen Chargingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Hydrogen Stress Cracking Behaviour in Dissimilar Welded Joints of Duplex Stainless Steel and Carbon Steel

Park

Moon

et al. 2021

Metals

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Effects of Nb on Stress Corrosion Cracking of Various Heat-Affected Zone Microstructures of E690 Steel under Cathodic Potential

Fan

Zhao

Chen

et al. 2023

J. of Materi Eng and Perform

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Effect of Electrochemical Hydrogen Charging Time on Hydrogen Embrittlement of the Hot-Rolled and Accelerated Cooling Treated API X70 Steel

Baek

Nahm

2021

Met. Mater. Int.

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This study investigated the effect of the hydrogen charging time on the hydrogen embrittlement of hot-rolled and acceleratedcooling treated API X70 steel by using the electrochemical hydrogen charging method. Tensile and V-notch Charpy impact test were completed for the specimens of hydrogen charged for 0, 2, 4, and 10 h, and then microstructural observation were performed. The tensile and yield strength tended to decrease slightly and the total elongation started to decrease rapidly up to 2 h charging time and then these gradually decreased with the hydrogen charging time. The post-uniform elongation increased slightly after the holding time of 2 h due to the occurrence of two-step stress reduction phenomenon and its mechanism has suggested. The effect of the hydrogen embrittlement on impact absorption energy according to the hydrogen charging time were also investigated. The fracture surface of the hydrogen charged ones are generally composed of cleavage fracture surfaces. It was demonstrated that the external cracks were formed on the outside of tensile tested specimen and the external shape of the fracture portion was fractured without large elongation at hydrogen charged specimens.

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Influence of hydrogen on softened heat-affected zones during in-situ slow strain rate testing in advanced high-strength steel welds

Cited by 18 publications

References 51 publications

Hydrogen Stress Cracking Behaviour in Dissimilar Welded Joints of Duplex Stainless Steel and Carbon Steel

Hydrogen Stress Cracking Behaviour in Dissimilar Welded Joints of Duplex Stainless Steel and Carbon Steel

Effects of Nb on Stress Corrosion Cracking of Various Heat-Affected Zone Microstructures of E690 Steel under Cathodic Potential

Effect of Electrochemical Hydrogen Charging Time on Hydrogen Embrittlement of the Hot-Rolled and Accelerated Cooling Treated API X70 Steel

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