The effect of manganese and chromium on surface oxidation products formed during batch annealing of low carbon steel strip

Authors

Paton Wilson, University of WollongongFollow
Zhixin Chen, University of WollongongFollow

RIS ID

15020

Publication Details

Wilson, P. R. & Chen, Z. (2007). The effect of manganese and chromium on surface oxidation products formed during batch annealing of low carbon steel strip. Corrosion Science, 49 (3), 1305-1320.

Abstract

Surface oxides formed at ferrite grain boundaries of low carbon steels annealed at 700 °C in 5% hydrogen 95% nitrogen atmosphere were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Two different oxides (Fe,Mn)O and MnCr₂O₄ are observed at the grain boundaries and the former is five-fold coarser than the latter. It was found at the annealing temperature of 700 °C that the mean particle size of the (Fe,Mn)O depends on the manganese content, and the mean particle size and distribution of the MnCr₂O₄ dependent on chromium, but independent of manganese. It is unlikely the coarse (Fe,Mn)O precipitates pose any potential risks to the electrolytic tin coating quality as they will be removed by the pickling operation prior to tinning. The potential risks posed by the MnCr₂O₄ to the quality of the electrolytic tin coating of tinplate products can be minimized by restricting the chromium content of the steel.