| abstract |
The high-strength steel sheet of the present invention contains predetermined chemical components, and the metallographic structure is calculated as an area ratio, which is composed of ferrite: 20%-70%; retained austenite: 5%-40%; primary martensite: 0% %～30%; total of tempered martensite and bainite: 20% to 75%; and total of pearlite and cementite: 0% to 10%, 1/8 thickness to 3% from the surface In the range of /8 thickness, the ratio of the number of retained austenite with an aspect ratio of 2.0 or more to the number of all retained austenite is 50% or more, in a cross section parallel to the rolling direction and perpendicular to the surface At the 1/4 position of the plate thickness, the standard deviation of the area ratio of ferrite measured at 10 points every 50mm along the plate width direction is less than 10%, and the tensile strength is more than 780MPa. |