Patent ID: 9546413
Date: 2017-01-17
CPC Classifications: B32B,C21D,C22C,C23C

Claim:
1. A hot-rolled steel sheet being a steel sheet having a chemical composition, by mass %, of C: 0.02% to 0.5%, Si: 0.001% to 4.0%, Mn: 0.001% to 4.0%, Al: 0.001% to 4.0%, P: 0.15% or less, S: 0.03% or less, N: 0.01% or less, O: 0.01% or less, and the balance comprising Fe and unavoidable impurities, wherein a sum of a content of the Si and a content of the Al is 1.0% to 4.0% in the chemical composition of the steel sheet, an average pole density of an orientation group from {100}<011> to {223}<110>, which is a pole density expressed by an arithmetic average of pole densities of respective crystal orientations {100}<011>, {116}<110>, {114}<110>, {112}<110>, and {223}<110>, is 1.0 to 6.5, and a pole density of a crystal orientation {332}<113> is 1.0 to 5.0 in a sheet thickness central portion within a range of ⅝ to ⅜ of a sheet thickness, a microstructure of the steel sheet includes a plurality of grains, the microstructure of the steel sheet includes, by an area ratio, 2% to 30% of retained austenite, 20% to 50% of ferrite, 10% to 60% of bainite, 20% or less of pearlite, and 20% or less of martensite, and rC that is a Lankford value in a direction orthogonal to a rolling direction is 0.70 to 1.10, and r30 that is a Lankford value in a direction forming an angle of 30° with the rolling direction is 0.70 to 1.10.