| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a Zn-Al-Mg based plated steel sheet which has a tensile strength of≥780 MPa and has both bendability and hot dip metal embrittlement resistance by finely adjusting steel components and structure.. <P>SOLUTION: The steel having a composition containing, by mass, 0.05 to 0.18% C, 0.1 to 0.8% Si, 1.5 to 2.3% Mn,≤0.05% P,≤0.01% S, 0.0005 to 0.005% B and 0.01 to 0.10% Ti, and having a metallic structure composed of ferrite as the main phase and martensite or martensite and bainite as the second phase, and in which the average grain size of the ferrite is≤8.0μm, the martensite has the average grain size of≤5.0μm and the average aspect ratio of≥0.7, and the area ratio of the martensite or the martensite and bainite is 15 to <45% is used as a base steel sheet. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
