On the local evaluation of the hydrogen susceptibility of cold-formed and heat treated advanced high strength steel (AHSS) sheets

Drexler, Andreas; Bergmann, C.; Manke, Gregor; Kokotin, V.; Mraczek, Klemens; Pohl, M.; Ecker, Werner

doi:10.1016/j.msea.2020.140276

Cited by 27 publications

(17 citation statements)

References 49 publications

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“…Similar to the results of this study, the diffusible hydrogen concentration integrates the hydrogen, which diffuses during isothermal heat treatment at 300 • C [23]. Therefore, the diffusible hydrogen concentration is a semi-phenomenological quantity and strongly depends on the thermal activation of trap sites [23,24], such as the sample thickness and the metallic coating with the surface treatment of the specimen. Depending on these conditions, it has to be pointed out that the diffusible hydrogen concentration cannot represent the lattice hydrogen concentration.…”

Section: Hydrogen Trapping On Steel Grades During the Hot Stamping Processsupporting

confidence: 79%

Hydrogen Absorption and Desorption Behavior on Aluminum-Coated Hot-Stamped Boron Steel during Hot Press Forming and Automotive Manufacturing Processes

Kim

Jung

et al. 2021

Materials

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Our study mainly focused on diffusible hydrogen in aluminum–silicon-coated hot-stamped boron steel during a hot press forming process and in pre-treatment sequential lines of the automotive manufacturing process using a thermal desorption spectroscopy (TDS) technique. First, in the hot stamping procedure, as the soaking time increased in the heating furnace at a specific dew point when austenitizing, a high concentration of diffusible hydrogen was absorbed into the hot-stamped boron steel. Based on the TDS analysis of hydrogen absorbed from hot stamping, the activation energy value of hydrogen trapping in 1.8 GPa grade steel is lower than that of 1.5 GPa grade steel. This means that diffusible hydrogen can be more easily diffused into defective sites of the microstructure at a higher level of the tensile strength grade. Second, in sequential pre-treatment lines of the automotive manufacturing process, additional hydrogen did not flow into the surface, and an electro-deposition process, including a baking procedure, was effective in removing diffusible hydrogen, which was similar to the residual hydrogen of the as-received state (i.e., initial cold rolled blank). Based on these results, the hydrogen absorption was facilitated during hot press forming, but the hydrogen was sequentially desorbed during automotive sequential lines on aluminum-coated hot-stamped steel parts.

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Section: Hydrogen Trapping On Steel Grades During the Hot Stamping Processsupporting

confidence: 79%

Hydrogen Absorption and Desorption Behavior on Aluminum-Coated Hot-Stamped Boron Steel during Hot Press Forming and Automotive Manufacturing Processes

Kim

Jung

et al. 2021

Materials

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“…Fitting the predictions of the bulk diffusion model to the measured TDS spectrum enables determining the binding energy, the trap density and the migration energy [20,25,38,42,43]. For that purpose, the bulk diffusion as given in Eq.…”

Section: Bulk Diffusion Modellingmentioning

confidence: 99%

“…Critical hydrogen sources are present during materials processing as well as during service [12,13]. Hydrogen can be absorbed at the surface, resulting in an inhomogenous hydrogen distribution [14][15][16][17] in the steels, which is strongly influenced by plastic deformation [18], residual stresses and edge conditions [19][20][21][22]. Hydrogen desorption at room temperature is a crucial problem during testing of hydrogen embrittlement [23], which makes determining the hydrogen embrittlement threshold for a given hydrogen content difficult.…”

Section: Introductionmentioning

confidence: 99%

“…The slower the loading rate, the longer is the total test duration. Typical hydrogen embrittlement tests may run for days to weeks [13,20,21,25]. During this time, hydrogen is desorbing from the surface of charged samples, which causes hydrogen diffusion-related difficulties in experimental testing and evaluation of internal hydrogen embrittlement.…”

Section: Introductionmentioning

confidence: 99%

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The role of hydrogen diffusion, trapping and desorption in dual phase steels

et al. 2022

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Hydrogen embrittlement (HE) of advanced high-strength steels is a crucial problem in the automotive industry, which may cause time-delayed failure of car body components. Practical approaches for evaluating the HE risk are often partially and contradictive in nature, because of hydrogen desorption during testing and inhomogenous hydrogen distributions in, e.g., notched samples. Therefore, the present work aims to provide fully parametrized and validated bulk diffusion models for three dual phase steels to simulate long-range chemical diffusion, trapping and hydrogen desorption from the surface. With one constant set of parameters, the models are able to predict the temperature dependency of measured Choo-Lee plots as well as the concentration dependency of measured effective diffusion coefficients. Finally, the parametrized and validated bulk diffusion models are applied for studying the role of the current density on the permeation time and the role of coatings as effective diffusion barriers. Graphical abstract

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“…This inhibits the loss of hydrogen during the test to ensure a sufficient concentration even at lower strain rates. Lower strain rates have also been shown to increase HE susceptibility since they allow for more diffusion of hydrogen towards critical areas like crack tips [11,25,26]. Several studies that test in-situ in gaseous hydrogen use autoclaves as a containment volume for the high pressure hydrogen gas [3,[27][28][29].…”

Section: Introductionmentioning

confidence: 99%

In-Situ Hollow Sample Setup Design for Mechanical Characterisation of Gaseous Hydrogen Embrittlement of Pipeline Steels and Welds

Boot

Riemslag

Reinton

et al. 2021

Metals

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This work discusses the design and demonstration of an in-situ test setup for testing pipeline steels in a high pressure gaseous hydrogen (H2) environment. A miniature hollow pipe-like tensile specimen was designed that acts as the gas containment volume during the test. Specific areas of the specimen can be forced to fracture by selective notching, as performed on the weldment. The volume of H2 used was minimised so the test can be performed safely without the need of specialised equipment. The setup is shown to be capable of characterising Hydrogen Embrittlement (HE) in steels through testing an X60 pipeline steel and its weldment. The percentage elongation (%El) of the base metal was found to be reduced by 40% when tested in 100 barg H2. Reduction of cross-sectional area (%RA) was found to decrease by 28% and 11% in the base metal and weld metal, respectively, when tested in 100 barg H2. Benchmark test were performed at 100 barg N2 pressure. SEM fractography further indicated a shift from normal ductile fracture mechanisms to a brittle transgranular (TG) quasi-cleavage (QC) type fracture that is characteristic of HE.

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On the local evaluation of the hydrogen susceptibility of cold-formed and heat treated advanced high strength steel (AHSS) sheets

Cited by 27 publications

References 49 publications

Hydrogen Absorption and Desorption Behavior on Aluminum-Coated Hot-Stamped Boron Steel during Hot Press Forming and Automotive Manufacturing Processes

Hydrogen Absorption and Desorption Behavior on Aluminum-Coated Hot-Stamped Boron Steel during Hot Press Forming and Automotive Manufacturing Processes

The role of hydrogen diffusion, trapping and desorption in dual phase steels

In-Situ Hollow Sample Setup Design for Mechanical Characterisation of Gaseous Hydrogen Embrittlement of Pipeline Steels and Welds

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