Corrosion Resistance of L120G13 Steel Castings Zone-Reinforced with Al2O3

Abstract

The aim of the study was to determine the effect of zone reinforcement of cast steel L120G13 with Al2O3 macro-particles on the corrosion resistance of the composite obtained in this way. The obtained results allow us to conclude that strengthening of cast steel with corundum, the aim of which was to significantly increase the abrasive wear resistance, did not significantly deteriorate corrosion resistance. SEM tests show that a permanent diffusion layer interface is formed at the boundary between cast steel and corundum. In this area, simple manganese segregation and reverse iron and chromium segregation were found. These elements pass from the liquid alloy to the surface layer of the corundum particles, causing the aluminium and oxygen to be pushed deep into the corundum grains. Corrosion tests indicate comparable corrosion resistance of cast steel L120G13 and the composite L120G13 + Al2O3. Moreover, no intergranular corrosion was found in the matrix of the composite and no signs of pitting corrosion were found in the areas of the interface between the phases of the composite. This information is extremely important from the point of view of the material’s service life. Observations of breakthrough of both materials obtained during fracture after potentiodynamic corrosion tests, immediately after freezing in liquid nitrogen, indicate cracking with plastic features and increased resistance to dynamic forces of cast steel L120G13 and the composite L120G13 + Al2O3.