Our Dished and Flared Aluminum tank head design is often times used for internal stiffening heads or surge baffles. Recently we have done some dished and flared stainless steel tank heads that are lids for vats. They utilize the flat flange area for the seal on the vat or vertical barrel. The flat flange area can vary anywhere from 1/4″ up to 3 or 4″. Just tell us what you need.