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The explosion of hydrogen gas storage cylinders on May 25, 1894, represents one of the most spectacular failure cases during the late industrialization period in Germany. With respect to modern applications to hydrogen storage as energy carrier, it has several times been referred to as precedent failure case for the whole industrial sector. The detailed investigation reports by Martens have thus gained interest in the last years, but also, because the publications in 1896 about his expertise already provided in September 1894 document one of the first and most comprehensive investigations which can be regarded as a nucleus for modern failure analysis.
After summarizing the newspaper reports in the introduction, the present contribution provides a review of Martens' reports targeted at the development of failure analyses and materials testing procedures as well as potential failure origins.
High temperature SSRT - ductility data from cathodic hydrogen charging of 10CrMo910 and 7CrMoVTiB1010 are implemented into a mathematical model of SCC at various operational conditions including temperatures, pH and dissolved hydrogen/oxygen contents as well as global stresses and material properties. The results show that, as a consequence of experimentally verified local acidification at initial anodic path corrosion, subsequent local hydrogen assisted cracking can be a controlling factor for SCC in high temperature water. As a particular effect at global stresses close to the yield point, operational temperatures around 270°C exhibit peak crack growth rates depending on dissolved hydrogen, oxygen, pH and global stress, which has been found to be consistent for both, experimental studies and mathematical modeling.
In the present work, the influence of deuterium on the microstructure of a duplex stainless steel type EN 1.4462 has been characterized by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) supported by scanning electron microscopy (SEM), focused ion beam (FIB), electron back scattered diffraction(EBSD) and energy dispersive x-ray (EDX) investigations. Characterization has been carried out before and after electrochemical charging with deuterium which has been used as a tracer, due to its similar behavior to hydrogen in the steel microstructure. In a first approach, the distribution of the deuterium occurring at temperatures above 58 °C has been visualized. Further it turned out that sub-surface micro blisters are formed in the ferrite-austenite interface, followed by the formation of needle shaped plates and subsequent cracking at the ferrite surface. In the austenite phase, parallel cracking alongside twins and hexagonal close packed (martensitic) regions has been observed. In both phases and even in the apparent interface, cracking has been associated with high deuterium concentrations, as compared to the surrounding undamaged microstructure. Sub-surface blistering in the ferrite has to be attributed to the accumulation and recombination of deuterium at the ferrite-austenite interface underneath the respective ferrite grains and after fast diffusing through this phase. Generally, the present application of chemometric imaging and structural analyses allows characterization of hydrogen assisted degradation at a sub-micron lateral resolution.
A seamless pipe made of AISI 321 stainless steel represented a part of a transportation Pipeline system for hydrogen-containing hot gas in a hydrocarbon cracking unit. After a service period of approximately 21 months, a segment of such pipe demonstrated the cracks, causing leakage and respective fire. For clarification of a failure root cause, various metallurgical investigations combined with numerical simulations have been applied. The results revealed that the rupture of seamless pipe was evidently influenced by hydrogen assisted cracking (HAC). An increased susceptibility of the alloy to HAC had to be attributed to its sensitive microstructure which was related to the occurrence of slip bands with a high quantity in austenite grains, particularly in the specific region underneath the outer wall surface. In addition, the intensity of restraint resulting from the T-joint weld configuration caused respectively higher triaxial stresses in the confined area on the outer wall surface where the crack started. The numerical simulations of hydrogen diffusion revealed that a uniform hydrogen concentration profile over the pipe wall thickness was reached when the service period was more than 20 months. This duration agreed well to the timeto-failure of the actual component. Considering additionally that the final stage of rupture by overload was preceded by severe HAC, as confirmed by the respective intergranular fracture topography.