Zinc-induced crack resistant steel plate and zinc fabrication method

摘要

Sheet steel resistant to cracks induced by zinc, the components of which are in percentages by weight: C: 0.05% -0.090% Si: = 0.20% Mn: 1.35% -1, 65% P: = 0.013% S: = 0.003% Cu: 0.10% -0.30% Ni: 0.20% -0.50% Mo: 0.05% -0, 20% Nb: 0.015% -0.035% Ti: 0.008% -0.018% N: = 0.0060% Ca: 0.0010% -0.0040% B: = 0.0002%, and the rest being Fe and unavoidable impurities; and at the same time the content of the aforementioned elements must satisfy the following relations: Mn / C = 15; [(% Mn) + 0.75 (% Mo)] x (% C) = 0.16; CEZ = 0.44%, where, CEZ = C + Si / 17 + Mn / 7.5 + Cu / 13 + Ni / 17 + Cr / 4.5 + Mo / 3 + V / 1.5 + Nb / 2 + Ti / 4.5 + 420B; Ni / Cu = 1.50; Nb / Ti = 1.8 and Ti / N is between 1.50 and 3.40; Ca / S is between 1.00 and 3.00, and (% Ca) x (% S) 0.28 = 1.0 x 10-3; a finished steel sheet has a mechanical strength at elongation = 460 MPa and a mechanical tensile strength = 550 MPa, the microstructure of the finished steel sheet are ferrite + bainite colonies that are very small and are distributed in a dispersed and homogeneous, with an average grain size controlled to no more than 10 μm, and the microstructure of a zone affected by welding heat is a very small and homogeneous amount of ferrite + a small amount of perlite.