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Medium Mn steels have been considered as the next-generation materials for use in the automotive industry due to their excellent strength and ductility balance. To reduce the total weight and improve the safety of vehicles, medium Mn steels look forward to a highly promising future. However, hydrogen-induced delayed cracking is a concern for the us...
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Hydrogen embrittlement (HE) has arisen as one of main issues for developing high-strength lightweight steels. The precipitation of fine particles providing as stable H-trapping sites is preferred to overcome the intrinsic HE of high-strength steels. However, studies on HE in high-strength lightweight steels along with roles of B2 particles have not...
Citations
... Humid air at high temperatures inhibits heat transfer due to reduced evaporation of sweat from the body surface, resulting in overheating of the body, deterioration of appetite [20] and reduced productivity [26]. The indirect effect of humidity on animal organisms is determined by an increase in the accumulation of harmful gases [35], microorganisms in the air [4,37], a decrease in the heat-shielding properties of the external enclosures of the room [6], corrosion of metal equipment [16], deterioration of feed preservation, quality products [40]. A change in relative humidity from 70 to 95% leads to an increase in mortality in pigs from 0.05 to 17.5%. ...
The article investigated the influence of systems for creating a microclimate with uniform pressure and geothermal negative pressure in combination with liquid and dry feeding systems on the parameters of the microclimatic environment in the piglet rearing room and the intensity of their growth. For this purpose, four groups of 150 pigs each were formed, two of which were kept with a uniform pressure ventilation system and two with negative pressure geothermal ventilation. For each ventilation system, one group was fed dry granulated compound feed, and two groups were fed liquid mixtures based on the same compound feed with an addition of 2.7 liters of water per kilogram of feed. The pigs were kept under the same conditions and were fed a diet that was equivalent in composition and nutritional value. Group I included piglets that received dry feed and were raised in a room with uniform pressure ventilation. The animals in the group II were kept in the same room, but consumed liquid feeds. Pigs in the III and IV groups were kept in rooms with geothermal ventilation. Piglets in the III group were fed dry feed, while piglets in the IV group were fed liquid feed. The results of the study showed that the ventilation system has an influence of 76.48% on relative humidity, 76.96% on ammonia content, 65.77% on carbon dioxide content and 65.07% on hydrogen sulfide content. The feeding system only affects the hydrogen sulfide content with a strength of 5.79%. Better microclimate parameters were provided by uniform pressure ventilation. Higher average daily gains, higher feed consumption, better feed conversion and lower cost per 1 kg gain were found in groups of pigs fed liquid feed and kept with geothermal ventilation.
... Such a low hydrogen content was achieved after 9-day exposure under the conditions used in the current work. Liu et al. [64] exposed steel specimens from a medium-manganese steel with tensile strength of 1600 MPa to humid air without any chloride pre-deposition and reported 1.6 ppm of absorbed hydrogen after just 3-day exposure, while elongation and tensile strength decreased by 64% and 13%, respectively. In the current work, between 0 and 0.1 ppm hydrogen was detected after 3-day exposure of the specimens with pre-deposited chlorides and the reported drop of mechanical properties seems to be unlikely under these conditions. ...
Hydrogen absorption into steel during atmospheric corrosion has been of a strong concern during last decades. It is technically important to investigate if hydrogen absorbed under atmospheric exposure conditions can significantly affect mechanical properties of steels. The present work studies changes of mechanical properties of dual phase (DP) advanced high strength steel specimens with sodium chloride deposits during corrosion in humid air using Slow Strain Rate Test (SSRT). Additional annealed specimens were used as reference in order to separate the possible effect of absorbed hydrogen from that of corrosion deterioration. Hydrogen entry was monitored in parallel experiments using hydrogen electric resistance sensor (HERS) and thermal desorption mass spectrometry (TDMS). SSRT results showed a drop in elongation and tensile strength by 42% and 6%, respectively, in 27 days of atmospheric exposure. However, this decrease cannot be attributed to the effect of absorbed hydrogen despite the increase in hydrogen content with time of exposure. Cross-cut analysis revealed considerable pitting, which was suggested to be the main reason for the degradation of mechanical properties.
