Patent ID: 10406780

Abstract:
Provided is a hot-dip galvannealed steel sheet for hot stamping use, in which a base steel sheet contains Si in an amount of 0.7% or more, and which has excellent joint strength at a spot-welded part and can exhibit excellent adhesion to a coating film after hot stamping and coating with requiring little restriction of a hot stamp step. In the hot-dip galvannealed steel sheet, a base steel sheet contains, in mass %, 0.10 to 0.5% of C, 0.7 to 2.5% of Si, 1.5 to 3% of Mn and 0.01 to 0.5% of Al. The hot-dip galvannealed steel sheet is characterized in that the Mn concentration in a plating layer is 0.20% or more, the plated amount is 75 g/m2 or less, and the oxygen concentration at the interface between the plating layer and the base steel sheet is 0.50% or less.