from the conferences organized by TANGER Ltd. provisional website
The presented paper is devoted to the comparison of hydrogen diffusion characteristics in three different kinds of TRIP steels (with higher phosphorus content, higher aluminum content and higher silicon content). The steels were tested in as-received state after standard heat treatment including two step annealing – an intercritical annealing and an annealing in the range of bainitic transformation and in states after 5 % and 10 % tensile deformation. Steel microstructures were analyzed by light microscopy, scanning electron microscopy and X - ray diffraction. Hydrogen diffusion characteristics were electrochemically measured by Devanathan-Stachurski method with a double cell separated by steel in the form of a thin membrane. Exit sides of the steel membrane were palladium coated to prevent from hydrogen atom recombination during permeation experiments. Hydrogen diffusion coefficients were calculated using the „time lag“ method. The lowest values of hydrogen diffusion coefficients were recorded in the TRIP steel with higher aluminum content, while the highest values were observed in the TRIP with higher phosphorus content. Phosphorus probably enhances hydrogen diffusion in steel. Very high sub-surface hydrogen concentrations were observed also in the TRIP steel with higher phosphorus content.Keywords: TRIP steel, hydrogen diffusion characteristics, electrochemical permeation method
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