| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high strength alloyed hot-dip galvanized hot-rolled steel sheet excellent in bendability and plating property and having a TS of ≥1,470 MPa, and to provide a method for producing the same. <P>SOLUTION: The high strength alloyed hot-dip galvanized hot-rolled steel sheet has a composition containing, by mass, 0.26-0.35% of C, ≤0.4% of Si, ≤1.0% of Mn, ≤0.03% of P, ≤0.01% of S, ≤0.07% of Al, ≤0.01% of N, ≤0.005% of Ti, and 1.2-1.8% of V, with the balance comprising Fe and inevitable impurities, and has a microstructure in which the area ratio of ferrite phase (F-phase) occupying in the whole matrix is ≥90%, and VC is precipitated in the F-phase, and further the ratio of the number of VCs each having a size less than 10 nm to the total number of VCs is ≥85%, and the amount of V dissolved as a solid solution in steel is ≤0.30 mass%, wherein the size of the VC is the average value of the sizes of VCs each represented by 2<SP POS="POST">1/2</SP>×L (L: length of one side of square plate), in the square plate-like VC observed from [001] orientation of the F-phase as the matrix with a TEM. <P>COPYRIGHT: (C)2012,JPO&INPIT |
