Unraveling the Effect of Martensite Volume Fraction on the Mechanical and Corrosion Properties of Low‐Carbon Dual‐Phase Steel

Abstract

The effect of martensite volume fraction on the mechanical and corrosion properties of low-carbon dual-phase steel is studied based on both step quenching (SQ) and intercritical annealing (IA) routes. For SQ samples, hardness and ultimate tensile strength decrease with increasing holding time at the intercritical temperature and reach a plateau, which is related to the decrease in the amount of martensite during annealing. Conversely, for the IA samples, hardness increases during holding at the intercritical temperature due to austenitization and reaches the same plateau. At a same martensite volume fraction, the work-hardening behavior of SQ samples is better than IA samples, which is related to both the finer grain size and smaller martensite islands in the former. At low martensite fractions, the corrosion properties are comparable with the asreceived ferritic-pearlitic sample. It is revealed that by decreasing the volume fraction of martensite in SQ samples, the corrosion current density (i corr ) decreases almost linearly, and at martensite content of zero, it reaches the i corr of the fully ferritic microstructure. The latter is found to be lower than the i corr of the as-received sample. Therefore, the real effect of martensite on corrosion properties is unraveled for the first time.

The effects of double intercritical annealing on microstructure and mechanical properties of 0.107C-2.39Mn-0.453Si dual phase steel

“…For the other conditions, a more homogeneous microstructure was observed with a less discrepancy of ferrite size between near surface and center areas. Overall, the martensite fraction increases with the increase of intercritical annealing temperature (Figure 6), which is similar to other studies [20][21][22]. For all temperature, DIA results in a lower martensite fraction than SIA and a significant decrease of martensite fraction was observed in the 730DIA and 780DIA.…”

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

“…It was generally seen in figure 3(b) that by grain refinement, i corr increases. This can be directly related to the effect of grain boundaries [7][8][9][10]. Due to the higher energy and chemical activity of grain boundaries, a high density of these boundaries increases the reactivity of the surface through increased electron activity and diffusion [5,6].…”

“…However, due to the higher energy and chemical activity of grain boundaries, a high density of these boundaries increases the reactivity of the surface through increased electron activity and diffusion [5,6], and hence, it can affect the corrosion resistance. Higher corrosion resistance performance results in longer service of the steel structures [7][8][9][10]. Therefore, studying the effect of grain size on the corrosion resistance of low carbon steel is an important subject.…”

Tempering kinetics and corrosion resistance of quenched and tempered AISI 4130 medium carbon steel

“…The obtained polarization curves are shown in Figure 3a. Based on these curves, i corr (corrosion current density) was obtained by the Tafel extrapolation method [38][39][40][41] and is listed in Table 1. Then, i corr was plotted versus hardness in Figure 3b.…”