Hydrogen Content In Steel Research Articles

Electrochemical Properties of Steels in a Model Hydrogen Galvanic Couple

We study the effect of preliminary hydrogenation of carbon and low-alloy steels on their electrochemical behavior in a hydrogen galvanic couple “hydrogenated-nonhydrogenated steel.” The hydrogenation conditions being equal, the current of a hydrogen galvanic couple is determined not by its electromotive force but by the degree of polarization of the electrodes, which depends on the ratio between their areas. The polarization relations show that the electrochemical processes in a hydrogen galvanic couple obey the laws of electrochemical kinetics and have an activation nature. The current of a hydrogen galvanic couple is proportional to the concentration of absorbed hydrogen in steels, and, correspondingly, this dependence can serve as a basis of a new method for the nondestructive testing of hydrogen content in steel. As the hydrogen content in steels increases, their electrochemical properties approach the properties of a juvenile surface: the electrolytic potential becomes more negative, the polarization decreases, and the rate of anodic reactions grows sharply.

硫化物応力割れ特性からみた１３Ｃｒ鋼油井管の使用限界

Safety use limit of API-13Cr steel tubular in terms of Sulfide Stress Cracking (SSC) property is studied. Since SSC is a phenomenon of hydrogen embrittlement, the hydrogen content in steel is a key factor to determine SSC susceptibility. The hydrogen content entering into steel and the critical hydrogen content of steel below which no SSC occurs were experimentally determined as a function of environmental factors and yield strength. Comparison of both values of hydrogen contents enables to estimate critical environmental conditions and yield strength. Estimation results by this method coincides well with data in several literatures.

Fatigue Crack Propagation and Hydrogen Embrittlement of Ship Structural Steel Plates

Corrosion fatigue crack propagation of ship structural steel plates such as KA36 (TMCP) has been investigated from a viewpoint of hydrogen embrittlement. Hydrogen permeation coefficient was measured to be about 0.11 μA/cm in sour crude oil with H2S and H2O. It was simulated by cathodic hydrogen charging in some electrolytic solution.In this condition, the crack propagation rate of KA36 (TMCP) steel was accelerated as well as in sour crude oil. It increased with an increase in hydrogen permeation coefficient. It was well coincident with the spacing per cycle of brittle striation, which was observed in the accelerated crack propagation area in both conditions. The crack propagation rate, da/dN, increased with a decrease in the cycle of stress.Hydrogen content near the crack tip in the, ΔK of 37 MPa√m might be about one order of magnitude more than that in base material, which was estimated by both the observation of dislocation density in the plastic deformation region and the measurement of hydrogen diffusion coefficient of cold rolled steels. As the result, the hydrogen content in steel near the crack tip in high ΔK region might be approximately 0.1 mass ppm.Considering these results, it was concluded that the environmental enhancement of the crack propagation rate in sour crude oil was due to hydrogen embrittlement.

A study of the hydrogen-induced degradation of two steels differing in sulfur content

Two steels with different sulfur contents: 0.003 and 0.024 wt pct, were cathodically charged under three different conditions and brought to fracture in tension immediately after charging or after aging at room temperature. All hydrogen charged specimens showed embrittlement, with a little higher loss of ductility in the high sulfur steel. The hydrogen embrittlement was reversible in both steels when specimens were charged in arsenic-free sulfuric acid solution at room temperature but was irreversible when charged in arsenic-containing acid at the same temperature. After charging in molten salts at 200 °C, some of the low sulfur steel specimens exhibited irreversible hydrogen damage with the appearance of quasicleavage fractures, while all high sulfur steel specimens were restored to the uncharged ductility by aging at room temperature. These results are interpreted by assuming that an increased sulfur content in steel increases the density of trapping sites for hydrogen at the sulfide/matrix interfaces. These traps are inactive above 150 °C and become operative after cooling. Therefore, at the same hydrogen content in steel after cooling, the greater content of sulfur results in a decreased activity of the lattice dissolved hydrogen, hence in reduced embrittlement.

Nelson 線図から求めた鋼中の臨界水素量と温度の関係

Nelson 線図から求めた鋼中の臨界水素量と温度の関係

A Study of the Entry and Removal of Hydrogen during Coating and Thermal Treatment of Steel

Abstract High strength steel wires were charged with hydrogen, electroplated with nickel, and baked at 191 C for 3 hours to relieve hydrogen embrittlement. To follow the entry and removal of hydrogen and its effects, measurement of (1) hydrogen contents of the wire and the coating, and (2) cracking susceptibility of the wire were made during each step of these processes. The results show that hydrogen introduced into steel during processes such as preplate acid cleaning and electroplating is initially present in a mobile form that causes embrittlement. Although postplate baking can relieve embrittlement by simply driving mobile hydrogen out of the steel, this work clearly demonstrates that baking can also relieve embrittlement by an alternate mechanism believed to involve driving the mobile species into internal trap sites. Because steel can accommodate process hydrogen in this innocuous trapped state, the total hydrogen content of steel as determined by high temperature extraction does not provide a reli...

Anomalous Corrosion of Austenitic Stainless Steel Exposed to Hydrogen at High Temperature and Pressure

Abstract The effect of dissolved hydrogen on intergranular and general corrosion of austenitic stainless steels was investigated. Hydrogenation was carried out in 1 to 28 MPa hydrogen at 723 K for 16 hours. The corrosion rate of hydrogenated AISI 304 stainless steel, with precipitated carbides in grain boundaries or contained martensites, was markedly greater than that of hydrogen-free ones. This anomalous corrosion increased with the hydrogen content of steel. The current density of the anodic polarization curves of hydrogenated specimens was greater than that of hydrogen-free ones, which coincided with the corrosion data. This anomalous corrosion recovered with the short time heating at 923 K and above, but not with the heating at 873 K and below. These behaviors can be interpreted by the formation of internal microdefects, which are active sites, and impair the passivation characteristics, caused by hydrogen trapping.

鉄鋼材料中の水素溶解量の新しい電気化学測定法

鉄鋼材料中の水素溶解量の新しい電気化学測定法

343. Investigation of the hydrogen content in steel: I Tar and L Hedai, Csepeli Muszaki Kozgazdasagi Szemle, 7 (1), 1969, 21–33 ( in Hungarian)

343. Investigation of the hydrogen content in steel: I Tar and L Hedai, Csepeli Muszaki Kozgazdasagi Szemle, 7 (1), 1969, 21–33 ( in Hungarian)

1437. Effect of the method of degassing on the hydrogen content of steel: Z Kliseiwicz, Hutnik, 33 (9), 1966, 357–361 ( in Polish)

1437. Effect of the method of degassing on the hydrogen content of steel: Z Kliseiwicz, Hutnik, 33 (9), 1966, 357–361 ( in Polish)

645. Some considerations on the results of the determination of hydrogen content in steel: G. Timo and U. Lodi, Metallurgia Italiana, 55, (1963), 560

645. Some considerations on the results of the determination of hydrogen content in steel: G. Timo and U. Lodi, Metallurgia Italiana, 55, (1963), 560

The effect of surface abrasion on the hydrogen content of steel

AbstractAbrasion of mild and stainless steel on a 3 M Company 120‐grade silicon carbide paper has been shown to increase the hydrogen content by 0·0049 and 0·0034 ml. per sq. cm. of apparent abraded area, respectively.The application of the results to the determination of hydrogen in steel is discussed and, in the particular case of mild‐steel sheet where the surface area may be as high as 200 sq. cm. per 100 g., the magnitude of the error due to abrasion on the above silicon carbide paper is sufficiently high to invalidate the determination of internal hydrogen on such materials unless appropriate corrections are made.