| 摘要 |
PROBLEM TO BE SOLVED: To provide steel excellent in laser weldability even without removing mill scales. SOLUTION: This steel is the one having a compsn. contg., by weight, 0.01 to 0.20% C, 0.01 to 1.5% Si, 0.2 to 2.0% Mn, <=0.02% P, <=0.02% S, 0.0005 to 1.0% Al, and the balance Fe with inevitable impurities, in which the thickness of mill scales is <=50 μm, and, moreover, 0.4<(0.88[%Al]+1.14[%Si])<1.5 is satisfied. It is preferable that the steel contains one or >=two kinds among Nb, V, Mo, Cu, Ni, Cr and B as well. |
