Abstract:
Objective Hydrogen diffusion law and performance of Q345R(HIC), SA516 Gr70N+316L composite steel plate and 316L in wet H2S environment was studied by hydrogen osmosis technology.
Methods The atomic hydrogen concentration, effective diffusion coefficient, strength, toughness and fracture morphology of the materials under different pH conditions were compared by methods of electrochemical hydrogenation technique, tensile test, impact test and fracture analysis.
Results The results show that the concentration of atomic hydrogen C0 and the effective diffusion coefficient Deff of hydrogen in Q345R(HIC) increase with the decrease of solution pH value. When pH=3, the C0 and Deff in Q345R(HIC) materials can reach 17 moL/m3 and 2.22×10-10 m2/s. The infiltration of large number of hydrogen atoms make the materials produce dislocation pin effect. Hydrogen hardening occurred, and white spots of hydrogen damage appeared in the material. No hydrogen damage occurred in 316L.
Conclusion The 316L composite layer can effectively avoid the damage of the diffusion hydrogen on the substrate SA516 Gr70N or Q345R. For Q345R (HIC), with the decrease of solution pH value, the more atomic hydrogen infiltrate into the material, the greater the damage of the material performance is.