Corrosion and Cavitation Resistances of Low Alloy Steel after Frictional-Mechanical Treatment

Abstract

Paper presents the results of the studies of wear, corrosion and cavitation resistances of the S355J2 low alloy medium carbon steel subjected to surface modification by friction-mechanical treatment, as tested in sea water simulated solution. To evaluate the effect of the surface treatment, the comparative studies of the corrosive properties of the steel before and after treatment have been considered. The treatment due to a severe plastic deformation enable forming nanocrystalline structure of steel with grain sizes in the range 20–50 nm and the favorable internal stress state within the treated layer. The research indicated as well that the applied surface treatment improved the steel resistance to the wear and erosion-corrosion but decreased the resistance to general corrosion and stress corrosion. The surface treated steel revealed the lower diffusivity and the lower transport of hydrogen into the material core. Hydrogen collecting within the surface layer did not proceed to the deeper layer of structural metal, and thus prevented it from the hydrogen cracking.

Keywords

• low alloyed medium carbon steel
• friction-mechanical treatment
• resistance to wear
• corrosion
• stress corrosion and cavitation
• hydrogen diffusion coefficient