Hydrogen Trap on the Microstructure of Cr-Mo Type Steels

Abstract

Microstructure influence on hydrogen trapping in a Cr-Mo type steels −2.25Cr 1Mo and 2.25Cr 1Mo 0.25V− was studied by means of electrochemical permeation test, thermal desorption spectrometry, scanning and transmission electron microscopy analysis. Both steels, used in hydrogenation reactors, in as received and artificial aged conditions exhibit a bainitic microstructure with CrxMoy and CrxMoyVz carbides finely dispersed. The hydrogen diffusivity for the 2.25Cr-1Mo-0.25V is lower than 2.25Cr-1Mo due to its higher carbide precipitation. At aged conditions TDS on samples cathodically charged with hydrogen showed an increase on the hydrogen trapping capacity for 2.25Cr-1Mo and a reduction for the vanadium modified steel, compared with the as-received state.

Hydrogen Diffusivity and Hydride Formation in Rich-Zirconium Alloys Used in Nuclear Reactors

“…The TDS technique was conducted in order to determine the hydrogen binding energy of different trap sites present in the microstructure of Zr alloys. The data acquisition system has already been described elsewhere [3]. The hydrided samples are placed in a quartz reactor under a continuous flow of high purity argon, used as a carrier gas.…”

Ab initio study of metal carbide hydrides in the 2.25Cr1Mo0.25V steel

“…Experimental results showed that the hydrogen diffusivity in 2.25Cr1Mo0.25V is lower than in 2.25Cr1Mo steel, however, the hydrogen solubility is higher. It has been reported that the hydrogen-induced cracking modes of these two alloys are completely different [10][11][12] . Studies have found that hydrogen can be trapped by carbides and dislocations in the vanadiummodified alloy, resulting in coarser carbide grains in 2.25Cr1Mo0.25V steel 13,14 .…”

Experimental investigation on the hydrogen embrittlement characteristics and mechanism of natural gas-hydrogen transportation pipeline steels

“…With the increase of hydrogen release time, the peak height of the curve of the low temperature peak gradually decreased. Lemus et al [21] investigated the microstructure influence on hydrogen trapping in a Cr-Mo type steels throuth electrochemical permeation test, TDS, SEM and TEM analysis. Their results demonstrated that there is an extra-peak below 200 °C , which was attributed to the hydrogen trapping of vanadium carbide.…”