For those downvoting, this comment does have a nugget of truth: it holds if the materials are equivalent. Curved surfaces are a lot stiffer and deform less easi

For those downvoting, this comment does have a nugget of truth: it holds if the materials are equivalent. Curved surfaces are a lot stiffer and deform less easily than flat surfaces because they have some out-of-plane depth to their overall shape. If you formed curved sheets out of this steel, it'd be tougher again than it is with flat surfaces.