| 摘要 |
A high strength galvanized steel sheet having a low yield stress and superior anti-aging property and bake hardenability and a method for manufacturing the same are provided, and even if a general heat treatment cycle in a CGl is performed, the high strength galvanized steel sheet can be obtained without using expensive Mo. The high strength galvanized steel sheet has a composition which contains, on a mass percent basis, 0.01% to less than 0.08% of C, 0.2% or less of Si, more than 1.0% to 1.8% of Mn, 0.10% or less of P, 0.03% or less of S, 0.1% or less of Al, 0.008% or less of N, more than 0.5% of Cr, and the balance being iron and inevitable impurities, in which 1.9‰¤Mn (mass percent)+1.3Cr (mass percent)‰¤2.8 holds. In addition, the microstructure includes a ferrite phase and 2% to 15% of martensite on an area ratio basis, and the total area ratio of perlite and/or bainite is 1.0% or less. In manufacturing the above high strength galvanized steel sheet, when annealing and galvanizing treatments are performed after cold rolling, the temperature and the cooling rate are controlled. |
