Anisotropy of corrosion properties of carbon, low-alloy, and high-alloy steels

The Influence of Crystallographic Texture and Niobium Stabilisation on the Corrosion Resistance of Ferritic Stainless Steel

“…By relating these textures to the main characteristic of stainless steel, that is, the corrosion resistance, one realizes that a high packing density of the crystallographic planes and orientations provides a better resistance against chemical attack and an improved passivation resistance and repassivation characteristics 10 . Some early studies [11][12] analysed the influence of structural texture of carbon, low-alloyed and high alloyed steel rods in the anisotropy of corrosion resistance and showed a strong dependence by the orientation of metal fibres, and recent studies reinforce this fact: the influence of fibre orientations on corrosion 13,14 . More recently, it has been concluded that the orientations <111> and <110> show a better corrosion and pitting resistance because of their high atomic density, and conversely, one expects to find worse corrosion and pitting resistance associated with orientations showing a lower atomic density [10][11][12][13][14][15][16] .…”

“…The pitting potential increases at 3.6 mm and decreases at the centre of the sample (2 mm), i.e., the corrosion resistance is reduced at the centre. Figure 7 shows the influence of the crystallographic texture on the pitting potential, because the crystallographic texture changes throughout the thickness of steel in the same way as the pitting potential, and demonstrating that the pitting phenomenon has an slightly anisotropic behaviour [11][12][13][14][15] . This anisotropic behaviour occurs because carbon segregation 22 is more intense in the centre of the slab in non-stabilised steel.…”