Hydrogen embrittlement of constructional steels

Astaf'ev, A. A.

doi:10.1007/bf00707152

Cited by 4 publications

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“…~J = 6.7%, which is close to the initial level of the ductility of the steel. Thus, the described experiments and the results of our earlier investigations [7,12] indicate unambiguously that an electric-current treatment of hydrogen-charged steel increases its ductility due to the transformation of proton hydrogen into molecular hydrogen, which cannot interact with the dislocations.…”

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Some regular features of hydrogen embrittlement of structural steels

Astaf'ev

1997

Met Sci Heat Treat

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This paper is devoted to the effect of cold treatment on the ductility of hydrogen-charged steel 34KhN3M at room temperature and on the amount of diffusion-mobile hydrogen released when the steel is heated in vacuum. The effect of the joint action of low temperature and electric-current treatment on the ductility of hydrogen-charged steel is assessed.Hydrogen segregations are the cause of hydrogen embrittlement in steel [1 -3]. The embrittlement appears upon formation of Cottrell hydrogen clouds as a result of hydrogen segregation on dislocations and surfaces of shear lines [4,5] or as a result of the interaction between hydrogen protons and dislocations generated in the deformation process [6].In [7] we established the dependence of the dissolution of hydrogen in steel on the volume of voids. With increase in the volume of voids the amount of hydrogen dissolved in the metal decreases and its total content increases.Voids and considerable regions of discontinuities and collectors appear at contacts of grain boundaries and on phase boundaries. In accordance with modern concepts [8] that envisage an "island" model of grain boundaries, an ideal junction of crystal lattices over the entire grain perimeter does not exist. In addition to regions of favorable junction of ctystal lattices there are considerable "defective" zones of weak junction in which crystal regions are deformed and there are clusters of dislocations and voids. The length of such a "defective" zone on grain boundaries is considerable and can reach up to 100 crystal lattice constants. In our opinion, the volume of "defective" regions depends on the grain size in the steel and increases with its growth. In addition, "defective" regions are encountered on phase boundaries due to the difference in the parameters of the crystal lattices of the contacting phases.It has been established in [1 -3, 6] that hydrogen embrittlement develops in the case where hydrogen is carried to the dislocations by the diffusion mechanism or where the dislocations are displaced at a low speed. In this connection, at low temperatures, when the diffusion processes are decelerated or have no time to occur due to the high deformation rate, hydrogen embrittlement is absent [4,9]. However, by TsNIITMASh Research and Production Association, Russia. the data of some authors [6, 9, 10] some steels have a minimum ductility at a temperature ranging from -40 to -80~In the present work 2 we conducted a preliminary cold treatment of hydrogen-charged specimens and then determined the ductility (the reduction of area ~) at room temperature and the content of proton hydrogen by the method of vacuum heating. Tensile-test specimens of steel 34KhN3M (0.3 -0.4% C, 0.7-1.1% Cr, 2.75 -3.25% Ni, 0.25 -0.40% Mo) 6 mm in diameter with a design length l = 5d were subjected to air hardening from 850~ and to electrolytic hydrogen-charging in a 26% solution of sulfuric acid for 5 min at 20~ After a 1-h hold in air the specimens were cooled from 0 to -196~ and subjected to a 30-min hold. Then they were held...

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Some regular features of hydrogen embrittlement of structural steels

Astaf'ev

1997

Met Sci Heat Treat

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“…Syngas storage vessels thus need to be large, have high working pressures, or have these in combination. Although hydrogen is known to embrittle metals, the concentrations and partial pressures of hydrogen typically found in syngas do not appear to require any special preventative measures (18)(19)(20)(21)(22) for syngas storage options used in this analysis. An additional potential problem resulting from the hydrogen content of syngas is that atomic hydrogen can diffuse through most metals (23).…”

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Storing Syngas Lowers the Carbon Price for Profitable Coal Gasification

Newcomer

Apt

2007

Environ. Sci. Technol.

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Integrated gasification combined cycle (IGCC) electric power generation systems with carbon capture and sequestration have desirable environmental qualities but are not profitable when the carbon dioxide price is less than approximately $50 per metric ton. We examine whether an IGCC facility that operates its gasifier continuously but stores the syngas and produces electricity only when daily prices are high may be profitable at significantly lower CO 2 prices. Using a probabilistic analysis, we have calculated the plant-level return on investment (ROI) and the value of syngas storage for IGCC facilities located in the U.S. Midwest using a range of storage configurations. Adding a second turbine to use the stored syngas to generate electricity at peak hours and implementing 12 h of above-ground highpressure syngas storage significantly increases the ROI and net present value. Storage lowers the carbon price at which IGCC enters the U.S. generation mix by approximately 25%.

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An Engineering-Economic Analysis of Syngas Storage

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Newcomer²,

Lave³

et al. 2002

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Hydrogen embrittlement of constructional steels

Cited by 4 publications

References 1 publication

Some regular features of hydrogen embrittlement of structural steels

Some regular features of hydrogen embrittlement of structural steels

Storing Syngas Lowers the Carbon Price for Profitable Coal Gasification

An Engineering-Economic Analysis of Syngas Storage

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