Effect of Hydrogen Charging Current Density on Hydrogen Trapping Behavior in Cu6.01Ni2.7Mn Steel

Copper-containing steel is widely used in ship plates and other marine engineering fields due to its excellent mechanical properties and good weldability. However, in hydrogen-containing media environments, ship plate steel is prone to hydrogen embrittlement during service. Existing research primarily focuses on steel grades with copper content below 3 wt.%, while the diffusion and trapping behavior of hydrogen in ultra-high copper steel with copper content exceeding 3 wt.% remains unclear. Therefore, this study designed an ultra-high copper content steel with a copper content of 6.01%, and investigated the diffusion behavior of hydrogen in the test steel under different hydrogen charging current densities through microstructure characterization, slow strain rate tensile testing, electrochemical hydrogen permeation, and internal friction tests. The results indicate that with an increase in hydrogen charging current density, the anti hydrogen embrittlement performance of the test steel is significantly improved without deteriorating its mechanical properties. At the same time, the hydrogen trap density increased by 167%, with the irreversible hydrogen trap density increasing by 76.3%, and the reversible hydrogen trap density increased significantly by 537.9%. A large number of microstructures, such as phase boundaries, grain boundaries, and dislocations, have formed inside the material, which have reversible trapping effects on hydrogen, effectively suppressing the migration of hydrogen in the crystal structure and reducing the embrittlement phenomenon caused by hydrogen. This study expands the application potential of copper containing steel in the field of ocean engineering, providing important reference for the future development of high-strength hydrogen embrittlement resistant copper steel with ultra-high copper content.