The Influence of Microstructural Variations on Hydrogen Absorbance and Tensile Properties at Elevated Hydrogen Levels for TRIP-Aided Bainitic Ferrite Steels

Bollinger, Andrea Lynn; Murakami, T.; Findley, Kip O.; Moor, Emmanuel De; Speer, John G.

doi:10.5006/3105

Cited by 7 publications

(6 citation statements)

References 15 publications

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“…However, the microstructure refined by low-temperature annealing can trap more hydrogen atoms at the interface (Yang et al , 2018). Ferrite has also been studied in dual-phase steels containing the ferrite phase (Bollinger et al , 2019; Garcia et al , 2015; Liu et al , 2018).…”

Section: Introductionmentioning

confidence: 99%

Ferrite effects on the hydrogen embrittlement of 17-4PH stainless steel

Zheng

Sun

Yan

et al. 2022

ACMM

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Purpose The purpose of this study is to investigate the effect of ferrite on hydrogen embrittlement (HE) of the 17-4PH stainless steels. Design/methodology/approach The effects of ferrite on HE of the 17-4PH stainless steels were investigated by observing microstructure and conducting slow-strain-rate tensile tests and hydrogen permeability tests. Findings The microstructure of the ferrite-bearing sample is lath martensite and banded ferrite, and the ferrite-free sample is lath martensite. After hydrogen charging, the plasticity of the two steels is significantly reduced, along with the tensile strength of the ferrite-free sample. The HE susceptibility of the ferrite-bearing sample is significantly lower than the ferrite-free steel, and the primary fracture modes gradually evolved from typical dimple to quasi-cleavage and intergranular cracking. After aging at 480°C for 4 h and hydrogen charging for 12 h, the 40.9% HE susceptibility of ferrite-bearing samples was the lowest. In addition, the hydrogen permeation tests show that ferrite is a fast diffusion channel for hydrogen, and the ferrite-bearing samples have higher effective hydrogen diffusivity and lower hydrogen concentration. Originality/value There are a few studies of the ferrite effect on the HE properties of martensitic precipitation hardening stainless steel.

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Section: Introductionmentioning

confidence: 99%

Ferrite effects on the hydrogen embrittlement of 17-4PH stainless steel

Zheng

Sun

Yan

et al. 2022

ACMM

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“…When austenite is enriched in carbon, its Ms (martensite start) temperature decreases, avoiding martensitic transformation during final cooling and giving the possibility of further bainitic transformation at lower temperatures [1,[13][14][15]. Bainitic microstructures with carbon enriched austenite are generally produced by isothermal treatments, after complete austenitisation, in the temperature range between Bs (bainite start) and Ms [16,17] or below Ms [18,19].…”

Section: Introductionmentioning

confidence: 99%

Effect of Multi-Step Austempering Treatment on the Microstructure and Mechanical Properties of a High Silicon Carbide-Free Bainitic Steel with Bimodal Bainite Distribution

Franceschi

Bettanini

Pezzato

et al. 2021

Metals

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The effect of multi-step austempering treatments on the microstructure and mechanical properties of a novel medium carbon high silicon carbide-free bainitic steel was studied. Five different isothermal treatment processes were selected, including single-step isothermal treatments above martensite start temperature (at 350 °C and 370 °C, respectively), and three kinds of two-step routes (370 °C + 300 °C, 370 °C + 250 °C, and 350 °C + 250 °C). In comparison with single-step austempering treatment adopting a two-step process, a microstructure with a bimodal-size distribution of bainitic ferrite and without martensite was obtained. Bainitic transformation was studied using dilatometry both for single-step and two-step routes and the specimens were completely characterised by electron microscopy (SEM and TEM), X-ray diffraction (XRD) and standard tensile tests. The mechanical response of the samples subjected to two-step routes was superior to those treated at a single temperature.

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“…The interface is susceptible to HE, possibly due to dislocations that accommodate the misfit between austenite and martensite [1]. Blocky austenite is a coarsened and equiaxed form of retained austenite (RA) in the microstructure and has shown a high sensitivity to HE [7].…”

Section: Introductionmentioning

confidence: 99%

“…This study utilized Q&P processing to explore the influence of RA on HE susceptibility at high strength levels and specifically investigated bar steel as opposed to previous research for sheet applications [3][4][5][6][7]. Q&P conditions were created using conventional furnace treatments and molten salt to stabilize austenite in a martensitic matrix before evaluating the mechanical properties via traditional tensile testing and slow strain rate tensile (SSRT) testing in a hydrogen environment created via cathodic pre-charging.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Embrittlement Resistance of High Strength 9260 Bar Steel Heat Treated by Quenching and Partitioning

Hoyt

Moor

Findley

2021

Heat Treating Conference

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The influence of microstructure on hydrogen embrittlement of high strength steels for fastener applications is explored in this study. Space limiting applications in areas such as the automotive or agricultural industries provide a need for higher strength fasteners. Albeit, hydrogen embrittlement susceptibility typically increases with strength. Using a 9260 steel alloy, the influence of retained austenite volume fraction in a martensitic matrix was evaluated with microstructures generated via quenching and partitioning. X-ray diffraction and scanning electron microscopy were used to assess the influence of retained austenite in the matrix with different quenching parameters. The quench temperatures varied from 160 °C up to 220 °C, and a constant partitioning temperature of 290 °C was employed for all quench and partitioned conditions. The target hardness for all testing conditions was 52-54 HRC. Slow strain rate tensile testing was conducted with cathodic hydrogen pre-charging that introduced a hydrogen concentration of 1.0-1.5 ppm to evaluate hydrogen embrittlement susceptibility of these various microstructures. The retained austenite volume fraction and carbon content varied with the initial quench temperature. Additionally, the lowest initial quench temperature employed, which had the highest austenite carbon content, had the greatest hydrogen embrittlement resistance for a hydrogen concentration level of 1.0-1.5 ppm.

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The Influence of Microstructural Variations on Hydrogen Absorbance and Tensile Properties at Elevated Hydrogen Levels for TRIP-Aided Bainitic Ferrite Steels

Cited by 7 publications

References 15 publications

Ferrite effects on the hydrogen embrittlement of 17-4PH stainless steel

Ferrite effects on the hydrogen embrittlement of 17-4PH stainless steel

Effect of Multi-Step Austempering Treatment on the Microstructure and Mechanical Properties of a High Silicon Carbide-Free Bainitic Steel with Bimodal Bainite Distribution

Hydrogen Embrittlement Resistance of High Strength 9260 Bar Steel Heat Treated by Quenching and Partitioning

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