The Research Of Hydrogen Permeation Behaviors And Environment Sensitive Fracture Mechanism Of High Strength Steel 35CrMo In Marine Atmosphere

Marine atmospheric corrosion environment is one of the marine corrosion environment. Metal and its alloy can occur environment sensitive fracture in marine atmosphere. Hydrogen embrittlement(HE) is one of the important forms of the environment sensitive fracture and it is induced by the interaction of the extra hydrogen in the metal and the stress. It is confirmed that hydrogen permeation is one of the primary causations of the metal failure. Hydrogen embrittlement makes the material strength descend and brings the disastrous accident. It is necessary to research the embrittlement mechanism and the hydrogen permeation behaviors of the metals in marine atmosphere. The research works are listed in below:1. The hydrogen permeation behaviors and corrosion weight losses of 35CrMo specimens with no stress were researched by using Devanathan-Stachurski's hydrogen permeation technique. This research works were composed with two parts. (1) the wet– dry cycle experiments; (2) the simulated marine atmosphere experiments. Experimental results showed that obvious hydrogen permeation behaviors can be observed and differed with the experimental conditions. Cl- ions, H2S and SO2 promoted the hydrogen permeation obviously. There was a clear linear correlation between the amount of hydrogen permeated and the corrosion weight loss.2. The effect of hydrogen permeation to the environment sensitive fracture of 35CrMo in the marine atmosphere environment was researched by using slow strain rate tensile test(SSRT). Experimental results showed that hydrogen permeation can increase the degree of environment sensitive fracture of 35CrMo and made the maximum load, fracture time and the strain of the specimens descend.3. The effect of the stress to the hydrogen permeation behavior in marine atmospheric corrosion environment was researched by using Devanathan-Stachurski's hydrogen permeation technique and slow strain rate tensile test. Experimental results showed that, hydrogen permeation current increased with stress under elastic deformation range, the earlier period of the plastic deformation, while decreased with the onset of plastic deformation and then reached a critical point after which increased.