Effect of grain size on the corrosion resistance of low carbon steel

Abstract

Systematic works on the effect of grain size on the corrosion resistance of low carbon steel are scant. In the present work, a spectrum of grain sizes was obtained by simple heat treatment routes in a typical low-carbon steel. It was revealed that two distinct stages for the dependency of corrosion current density (i corr ) on the grain size exist. Above a limiting average grain size of ∼22 μm, i corr decreased slowly with increasing grain size. However, below this limiting value, i corr increased rapidly, which was related to the increased density of grain boundaries as interpreted by theoretical calculation of number of grains per unit area. Conclusively, a grain size of ∼22 μm (ASTM grain-size number of 8) was considered to be an optimum value according to the mechanical and corrosion standpoints.

The effect of Al and Nb contents, cooling rate and rolling condition on the microstructure and corrosion behaviour of HSLA steel

“…The refinement of grain size is known to increase the corrosion rate due to the increased number of active sites in the grain boundaries [31]. However, Nb contributed to activate passivation, providing a protective film on the surface, that is rich in carbide, oxide and Nb, to enhance corrosion resistance (Table 4).…”

An overwiew on corrosion behavior of steels in factory

“…Materials with small particle size have some advantages like high resistance, high toughness and high fatigue life. Since the decrease in particle size increases resistance, it is possible to say that it will also increase corrosion resistance [21]. As seen from Figure 7, corrosion rate is high in samples S1 and S2, because protective layer did not form at the beginning.…”

Influence of the Boriding Process on the Properties and the Structure of the Steel S265 and the Steel X6CrNiTi18-10

“…However, its grain structure significantly coarsened during the boriding process. The coarsening of the grain structure further affects the rate at which the steel matrix corrodes [13][14][15]. Due to the coarsening of the structure of the material, the density of the grain boundaries in its surface layer is reduced.…”