| 摘要 |
PROBLEM TO BE SOLVED: To provide a hot-dip Zn-Al-Mg coated steel sheet causing no working crack due to liquid metal embrittlement in a weld heat-affected zone even if subjected to welding by regulating the components, chemical composition and structure of steel as a basis material. SOLUTION: A steel sheet as a basis material, having a composition which consists of, by mass, 0.03 to 0.30% C,≤0.5% Si, 0.05 to 2.0% Mn,≤0.1% P,≤0.03% S,≤0.05% N,≤0.1% sol.Al and the balance essentially Fe and further contains 0.0001 to 0.0080 mass% B if necessary and in which the total content of Ti, Nb, V and Zr is limited to≤0.02 mass% and also having a structure before welding regulated to a mixed structure consisting of 10 to 70% ferrite by area fraction and the balance bainite, pearlite or martensite, is subjected to hot-dip Zn-Al-Mg coating. As a hot-dip Zn-Al-Mg coating layer, that containing 4 to 22 mass% Al and 0.05 to 10 mass% Mg is preferred. COPYRIGHT: (C)2005,JPO&NCIPI
|
