Development of Low Carbon Cold Rolled Steel Sheets for Enameling Application

The mechanical properties and microstructure of three grades of aluminum-killed low-carbon steel (A: 0.05 %C, B: 0.009 %C, 0.057% Ti; and C: 0.006 %C, 0.053 %Ti) after cold rolling and annealing at 600°C - 900°C for 6-12 hours have been studied. In general, the normal anisotropy (r) and degree of texture of the titanium-containing steels are higher than those of the plain carbon steel, with steel B (0.009 %C, 0.57 %Ti) being the highest. The one exception to this trend is steel B (0.009 %C, 0.57 %Ti) after annealing at 900°C, which may have been annealed in the two-phase ferrite + austenite phase region. There is a strong correlation between normal anisotropy and degree of texture and both increase with increasing annealing temperature. With the exception of steel B (0.009 %C, 0.57 %Ti) after annealing at 900°C, all steels have similar ultimate tensile strengths, but the yield strengths of the titanium-containing steels are much lower than those of the plain carbon steel. The cementite precipitates formed in the plain carbon steels are smaller than the Ti(C,N) particles formed in the titanium-containing steel, and the void sizes are similarly larger in the titanium-containing steels. The absence of fish scale defects in the enamel coatings on any of the steels, indicates that the voids are sufficient to accommodate evolved hydrogen.