| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-strength hot-dip galvanized steel sheet which has high strength (tensile strength TS of 540 MPa or higher) and has excellent processability (high ductility and high hole-expansibility) and spot weldability, and to provide a method for producing the steel sheet. SOLUTION: The high-strength hot-dip galvanized steel sheet has a composition which contains, in terms of mass%, 0.04%-0.10% C, 0.7%-2.3% Si, 0.8%-2.0% Mn,≤0.03% P,≤0.003% S,≤0.1% Al, and≤0.008% N, and satisfies [C%]×[Si%]≤0.20 (wherein [C%] and [Si%] indicate the contents (mass%) of C and Si, respectively), with the remainder comprising iron and inevitable impurities. The galvanized steel sheet has a structure which comprises, in terms of areal proportion,≥75% ferrite phase,≥1% bainitic ferrite phase, and 1%-10% pearlite phase, has a martensite phase content of <5% in terms of areal proportion, and satisfies (areal proportion of martensite)/((areal proportion of bainitic ferrite)+(areal proportion of pearlite))≤0.6. COPYRIGHT: (C)2011,JPO&INPIT
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