All the specimens were cut from industrial plates with the thickness
of 20 mm,which were processed by thermomechanical control process
(TMCP) technology. Table 1 shows the chemical compositions of the
two investigated steels. Results of optical microscopy observation of
the two steels are shown in Fig. 1, which indicate that the microstructures
of both these two steels are ferrite–pearlite. Thus the effects of
differentmicrostructures between the two steels on corrosion behavior
can be neglected.