| 摘要 |
The present invention provides a high-strength plated steel sheet having excellent corrosion resistance in a welded portion, molten metal embrittlement cracking resistance, and bending workability, using a high-strength molten Zn-Al-Mg-based plated steel sheet for a welded structural member. The high-strength molten Zn-Al-Mg-based plated steel sheet has a steel composition containing, in percentage by mass, 0.050 to 0.150% of C, 0.001 to 1.00% of Si, 1.00 to 2.50% of Mn, 0.005 to 0.050% of P, 0.001 to 0.020% of S, and 0.005 to 0.100% of Al. The high-strength molten Zn-Al-Mg-based plated steel sheet includes a steel base material having a metallographic structure comprising a ferrite phase and a second phase, the second phase mainly including martensite having an average crystal grain diameter of 8 μm or less. The sheet thickness t (mm) and chemical composition of the steel base material are adjusted so that C/0.2+Si/5.0+Mn/1.3+Cr/1.0+Mo/1.2+0.4t-0.7(Cr+Mo)1/2 will be 2.9 or less. |
