| 摘要 |
Technical abstract The invention deals with a process for manufacturing a hot-dip galvannealed steel sheet having a TRIP microstructure, and comprising, by % by weight, 0.01 ‰¤ C ‰¤ 0.22%, 0.50 ‰¤ Mn ‰¤ 2.0%, 0.2 ‰¤ Si ‰¤ 2.0%, 0.005 ‰¤ Al ‰¤ 2.0%, Mo < 0.01 %, Cr ‰¤ 1.0%, P < 0.02%, Ti ‰¤ 0.20%, V ‰¤ 0.40%, Ni ‰¤ 1.0%, Nb ‰¤ 0.20%, the balance of the composition being iron and unavoidable impurities resulting from the smelting, said process comprising the steps consisting in:
- oxidizing said steel sheet in order to form a layer of iron oxide on the surface of the steel sheet, and to form an internal oxide of at least one type of oxide selected from the group consisting of Si oxide, Mn oxide, Al oxide, complex oxide comprising Si and Mn, complex oxide comprising Si and Al complex oxide comprising Al and Mn, and complex comprising Si, Mn and Al,
- reducing said oxidized steel sheet in order to reduce the layer of iron oxide,
- hot-dip galvanising said reduced steel sheet to form a zinc-based coated steel sheet, and
- subjecting said zinc-based coated steel sheet to an alloying treatment to form a galvannealed steel sheet. |
