Study on the hydrogen-induced delayed fracture behavior of Q-P980 and MS980

In this paper, the hydrogen diffusion behavior and hydrogen induced delayed fracture (HIDF) of Q-P980 (Q-P: Quenching and Partitioning) and MS980 (MS: Martensitic steel) steels were investigated using hydrogen penetration, slow strain rate tensile (SSRT) tests, thermal desorption spectroscopy (TDS) tests, fracture analysis, and microstructural examination in this paper. The austenite in Q-P980 is massive retained-austenite (RA) with low stability. The TRIP (Transformation Induced Plasticity) effect will occur in the process of strain and change into high carbon martensite. HIDF is caused by a substantial amount of surplus hydrogen being enriched at the border and flaws. The fracture has a broad cleavage surface and is a typical quasi-cleavage fracture. MS980 has been sufficiently tempered, resulting in a substantial quantity of distributed spherical cementite (150nm) precipitating around the lath martensite. This size and form of cementite may successfully trap hydrogen while maintaining the material's mechanical characteristics. And tempering can effectively reduce the local stress level of steel, so MS980 has a very low HE susceptibility. HIDF is related to local stress and hydrogen accumulation. We suppose that Z is a constant and ZC is a critical value which associated to σ and CH (the local stress and local hydrogen concentration), rising as σ and CH rises. The atomic bonds at the crack tip, lattice position and the phase interface will fracture when ZC reaches a particular value Z. Tempering to minimize local stress and carbide precipitation to capture hydrogen are two strategies for reducing hydrogen embrittlement (HE) susceptibility, particularly for dislocation strengthened steel. Microalloying elements can generate precipitates that function as hydrogen traps and obstruct the HELP (Hydrogen Enhanced Localized Plasticity) process, lowering local stress and hydrogen accumulation.

On Novel Aspects of Hydrogen Effects on Applied Stress - Coupled Micromagnetic Activity in a Mild Steel After Exposure to NaCl – Water Solution: A Combined Approach

Hydrogen produced after exposure of a low – carbon steel to corrosive NaCl – Water solution may affect various its tensile mechanical and magnetic microstructural behaviour in a complex manner. This was investigated by introducing a relevant micromagnetic specific emission (ME) - response of this ferromagnetic material, where related processes and parameters of micromagnetic activity and mechanical response were implemented. In this manner, it was demonstrated that an increase in the hydrogen accumulation with corrosion time leads to an associated increase in the embrittling effect expressed by a substantial loss in the ductility of material. The competive and opposing effects of cumulative hydrogen, applied stress and plastic strain – induced microstructural damage were related to the specific ME- response parameter by which an increased magnetic hardening tendency of material with corrosion time was possible to establish. In this fashion and by using a stress as well as strain mode of presentation- aided combined approach, the complex interplay between micromagnetic activity, hydrogen accumulation and applied stress-strain was better revieled and analysed. It was also shown that the embrittlement is a product of hydrogen accumulation introduced by two highly localized processes. As such, accumulation occurs in two characteristic parallel ways: one of a common lattice diffusion and one of hydrogen transport and redistribution by moving dislocation towards the affected sites. Concerning the highly localized effects the dominating role of hydrogen – induced damage in form void initiation and growth over the hydrogen – assisted stress relief was reasonably demonstrated by using a simple modelling approach. Based on a mechanism of moving dislocation – assisted interaction between commulative hydrogen and magnetic domain walls, a Portervin – Le Chatelier – type micromagnetic process of a cooperative-corelated domain wall transport was proposed to explain certain subtle, quasiperiodic behaviour of ME- response. In the frame of the above findings the superior sensivity of ME – response compared to the mechanical one in early detecting cumulative hydrogen – assisted microstructural damage changes can be d educed.

The results of direct-prospecting geophysical methods used for the detection and localization of zones of hydrogen accumulation and migration in the Earth and the Moon cross-sections

The results of experimental studies at the hydrogen production site, hydrogen degassing sites in various regions, as well as on the Moon are presented. Experiments using the direct-prospecting technology of frequency- resonance processing and interpretation of satellite images and photographs are carried out in order to study the features of the deep structure in the areas of hydrogen degassing. The results of instrumental measurements indicate that, in the areas of the basalt volcanoes location with roots at different depths, signals at hydrogen frequencies are almost always recorded. When scanning the cross-section, responses from hydrogen are recorded practically from the upper edges of basalt volcanoes to their roots. Therefore, it can be assumed that basaltic volcanoes are a kind of channels through which hydrogen migrates to the upper horizons of the crosssection and further into the atmosphere. Deep (living) water is synthesized within many basalt volcanoes at a depth of 68 km. Hydrogen-rich water is healing and can be used for wellness purposes. All previously surveyed longevity zones on the Earth are located within basalt volcanoes, in which water synthesized at a depth of 68 km migrates to the surface and is used for the water supply. Hydrogen deposits can be formed by basaltic volcanoes in adjacent sealed reservoirs. The Mali hydrogen production site is located outside the contour of the basalt volcano; hydrogen responses were recorded from marl at the well site. At local sites in the Carpathians, signals from hydrogen are obtained from dolomites and marls. Hydrogen deposits formed near basalt volcanoes in different types of reservoirs can be discovered and localized during areal exploration using the methods of frequency- resonance processing of satellite images and photographs. Direct-prospecting technology can also be used to study reservoirs in crystalline rocks (including basalts). The materials of the article, as well as the previously published results of experimental work in various regions, indicate the advisability of using direct-prospecting methods of frequency–resonance processing of satellite images and photographs to detect zones of hydrogen accumulation in areas, where basalt volcanoes are located, as well as in areas of hydrogen degassing. The use of the mobile low-cost technology will significantly speed up the exploration process for hydrogen, as well as reduce the financial costs for its implementation.