| abstract |
Provided is a steel sheet of the strain aging hardening type which combines ordinary-temperature non-aging properties with baking hardenability and has excellent aging resistance after paint baking. The steel sheet of the strain aging hardening type, which has excellent aging resistance after paint baking, contains, in terms of mass%, 0.0010-0.010% C, 0.005-1.0% Si, 0.08-1.0% Mn, 0.003-0.10% P, 0.0005-0.020% S, 0.010-0.10% Al, 0.005-0.20% Cr, 0.005-0.20% Mo, 0.002-0.10% Ti, 0.002-0.10% Nb, and 0.001-0.005% N, with the remainder comprising Fe and incidental impurities, and has a ferrite content of 98% or higher, the ferrite having an average grain diameter of 5-30 μm. In the steel sheet, the part located at a depth of 1/2 the sheet thickness and the surface-layer part each has a minimum dislocation density of 51012 or more and have an average dislocation density in the range of 51012-11015 per m<SP>2</SP>. |