Hot-dip hot-dip steel sheet for press working with excellent low-temperature toughness and corrosion resistance and its manufacturing method

摘要

A hot-dip plated high-strength steel sheet for presswork having a tensile strength of 340 MPa or more and less than 540 MPa, a press formability capable of being applied to a fuel tank, excellent secondary work brittleness resistance and low-temperature toughness of a seam weld zone, and excellent corrosion resistance, is provided. It is characterized in that, in a high-strength steel sheet having a hot-dip plated layer on a surface of a cold-rolled steel sheet, the cold-rolled steel sheet contains, by mass %, C: 0.0005 to 0.0050%, Si: 0.30% or less, Mn: 0.70 to 3.00%, P: 0.05% or less, Ti: 0.01 to 0.05%, Nb: 0.01 to 0.04%, B: 0.0005 to 0.0030%, S: 0.01% or less, Al: 0.01 to 0.30%, N: 0.0005 to 0.010%, and a balance composed of Fe and inevitable impurities, and when the Ti content (%) is set to [Ti], the B content (%) is set to [B], and the P content (%) is set to [P], TB* defined by the following expression A is 0.03 to 0.06, and [B] and [P] satisfy the following expression B. TB*=(0.11[Ti])/(ln([B]×10000))A [P]10×[B]+0.03B