| 摘要 |
PROBLEM TO BE SOLVED: To provide a retained austenite-containing high strength thin steel sheet excellent in formability under ordinary treating conditions in the existing hot dip galvanizing line and to provide a producing method therefor. SOLUTION: This hot dip galvanized high strength thin steel sheet excellent in formability has a composition containing, by mass, 0.05 to 0.2% C, 0.3 to 2.5% Si, 0.5 to 3.0% Mn, <=0.1% P, <=0.040% Al, 0.01 to 0.20% Mo, 0.0010 to 0.0100% N, and the balance Fe with inevitable impurities, in which Mn, Mo and Si satisfy, by mass%, 3.3-1.1 Si>Mn>2.3-1.1 Si and also 8.33×10-2-0.01 Mn-4.44×10-2×Si<Mo<0.303-0.05 Mn-4.44×10-2×Si, contains retained austenite containing carbon of >=0.9% by the average concentration in >=3% by volume and contains equi-axed ferrite of 0.5 to 3.0% by aspect ratio.
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